Open access peer-reviewed chapter

Cytotoxicity and Apoptosis Induction by Coumarins in CLL

Written By

Omid Gholami

Submitted: June 20th, 2017 Reviewed: November 14th, 2017 Published: February 5th, 2018

DOI: 10.5772/intechopen.72446

Chapter metrics overview

1,200 Chapter Downloads

View Full Metrics


Chronic lymphocytic leukemia (CLL) is one of the leukemia types. Leukemia is cancer of the body's blood-forming cells. Cancer is a disease that is often characterized by too little apoptosis and uncontrolled duplicate of body cells. Apoptosis, or programmed cell death, is a normal component of the development and health of multicellular organisms. Cells die in response to a variety of stimuli during apoptosis. During cancer, pathophysiology apoptosis of the cancerous cells is disrupted, so one of the strategies for cancer chemotherapy is inducing apoptosis in cancerous cells. Myeloid cell leukemia type 1 (Mcl-1) is one of the antiapoptotic Bcl-2 family proteins. It has been shown that the expression of Mcl-1 in CLL is significantly associated with a failure to achieve complete remission following cytotoxic therapy, so regulation of Mcl-1 expression by coumarins could be one of the mechanisms of CLL chemotherapy. Coumarins consist of a large class of phenolic substances found in plants. Different pharmacologic effects of coumarins were reported. One of these effects is cytotoxicity and apoptosis induction in cancerous cells by coumarins. In this chapter, the cytotoxic activity of coumarins and their role in Mcl-1 regulation are discussed.


  • coumarins
  • apoptosis induction
  • Mcl-1 expression

1. Chronic lymphocytic leukemia

One of the most prevalent types of leukemia is chronic lymphocytic leukemia (CLL). Leukemia is a type of cancer. Cancer means too little apoptosis of body cells. In the case of cancer, cells have mutations that prevent them from undergoing apoptosis. It is a general belief that CLL is an indolent disease associated with a prolonged (i.e., 10–20 years) clinical course, and unrelated causes to CLL lead to death. But it is true only for less than 30% of cases [1]. By convention, the history of chronic lymphocytic leukemia begins in 1845, but it could be said to have started when the first white cells, “the globuli albicanates,” were noted by Joseph Lieutaud in 1749. During the intervening years, many events have aided in our understanding of the etiology and treatment of CLL. In his discussion of the history of CLL, Rai [2] found it informative to define three eras: (1) the recognition of CLL as a clinical entity, 1845–1924; (2) initial clinical investigations, 1924–1973; and (3) the modern era, 1973–2002.

Overexpression of Bcl-21 and Fas-inhibitory molecules such as TOSO is the principle mechanism of apoptosis resistance in CLL cells. CLL lymphocytes are clonal B-cells arrested in the B-cell differentiation pathway at some intermediate stage between the pre-B-cell and mature B-cell, perhaps in the “activated, antigen-experienced” B-cell subset. Phenotypic features of B-cell CLL (B-CLL) lymphocytes are [3, 4, 5] (1) extremely low levels of surface membrane immunoglobulin (often abbreviated as SmIg or sIg), (2) expression of one or more B-cell-associated antigens (like CD19, CD20, CD21, CD23, and CD24) [6, 7], and (3) expression of CD5, a T-cell-associated antigen.

Until the early 1980s, it was not possible to study chromosomal abnormalities in CLL because of the inadequate number of metaphases induced by available techniques. Certain genetic abnormalities have been associated with patient outcomes. Patients with complex genomic changes appear to have more aggressive disease [8]. The most frequently observed abnormalities were trisomy 12 and 14q+. The cytogenetic abnormalities appear to be restricted to B-cells in B-CLL [9]. In two studies of patients with CLL using fluorescence in situ hybridization (FISH) techniques, chromosomal abnormalities were noted in 69–82% of the patients, with abnormalities of chromosomes 11, 12, and 13 being most commonly seen.

1.1. Pathophysiology

Chronic lymphocytic leukemia is a monoclonal disease of mature-appearing lymphocytes that accumulate in blood, lymph nodes, spleen, liver, and bone marrow. Most cases (>95%) are characterized by monoclonal lymphocytes expressing normal B-cell surface proteins including immunoglobulin (Ig), CD19, and CD20 and aberrantly expressing CD5, a protein normally found on T-cells. A small minority (<5%) of cases are of T-cell origin, expressing T-cell surface markers such as CD3 and CD4 or CD8. These T-cell leukemias are not uncommon in individuals with ataxia telangiectasia. The molecular biology of T-cell lymphocytic leukemia is distinct from that of B-cell CLL [10].

Molecular and cellular mechanisms of CLL can be divided into two parts.

1.1.1. B-cell receptor-signaling pathways

B-cell receptor (BCR)-signaling pathways are triggered with or without antigen ligation in CLL. After antigenic BCR triggering downstream signaling of the BCR is dominated by the kinases lyn and syk, which transduce survival and antiapoptotic signals [11]. In CLL, the elevated expression of antiapoptotic Mcl-1, which leads to increased survival of malignant cells, occurred by prolonged activation of the MEK/ERK2 and Pi3K/AKT3 pathways and with AKT after BCR signaling (Figure 1) [12].

Figure 1.

The role of BCR signaling in the biology of CLL [15].

For establishment of BCR-signaling pathways independent of antigen ligation, CD19 is an important surface marker. It has an important role in regulation and amplification of signal transduction via lyn [13]. ZaP-70 is another tyrosine kinase that has important role in BCR signaling. When syk is not expressed, it can partially restore BCR signaling [14].

1.1.2. Aberrant apoptotic signaling pathway

Apoptosis is a kind of cell death. Extrinsic pathway of apoptosis triggers by death receptors. In CLL, they are CD95/Fas and trail (tumor-necrosis factor-related apoptosis-inducing ligand). After ligation by ligands (like CD40L), these receptors directly feed into a caspase cascade and lead to cell death [16]. The intrinsic pathway, or mitochondrial pathway, is regulated by the balance between antiapoptotic and proapoptotic members of the Bcl-2 family [15]. “BH3-only” proteins (e.g., Bim, Bid, Bmf, Puma, Bad, and noxa) are another class of Bcl-2 family proteins which can modify this balance (Figure 2).

Figure 2.

The interaction between Bcl-2 family member proteins [15].

Non-death-transmitted signals drive from developmental cues or sensor platforms. Developmental cues like Bim-dependent B-cell killing upon BCR cross-linking [17] and sensor platforms like the DNA damage sensor network involving the ATM (ataxia telangiectasia mutated) and p53 tumor suppressors, which prominently determine survival and treatment outcomes in CLL [15].

Currently, one of the therapeutic strategies that kill CLL cells is the DNA damage response via p53 that leads to a dominant cell-death signal via Puma [18, 19]. A major problem encountered with this strategy is that a number of patients with CLL harbor defects in the DNA damage machinery that leads to deactivation of the pathway. The challenge thus seems to be to bypass such resistance and produce p53-independent cell death [15].

Another therapeutic strategy is the exploitation of CD95 signaling. But it seems to be restricted, as systemic CD95 triggering leads to fulminant liver toxicity [20]. The role of trail receptor targeting is currently under development. CD40 signaling may also have a positive effect on conventional therapy. It has been shown that CD154 (CD40L) application was able to induce the p53-related transcription factor p73, leading to a sensitization of p53-deficient CLL cells to conventional therapeutics such as fludarabine [21].

A number of approaches have been taken to directly modulate the core components of the Bcl-2 cell-death machinery. The Bcl-2 antisense molecule oblimersen is the most advanced agent in clinical testing. “BH3-mimetics” and “pan-Bcl-2 family antagonists” can mimic the BH3 domain of BH3-only death-inducing proteins and are thought to liberate BH3-only proteins from the inhibition by antiapoptotic Bcl-2 proteins, thus making them effective killers.


2. Apoptosis

Apoptosis means cell suicide. It is a normal component of the development and health of multicellular organisms. Cells perform in a controlled, regulated fashion by apoptosis. Apoptosis is different from another form of cell death called necrosis [22]. Cancer is often characterized by too little apoptosis. In the case of cancer, damaged cells, which should undergo apoptosis, have mutations that prevent them from undergoing apoptosis [22]. Apoptotic cells can be recognized by stereotypical morphological changes (Figure 3).

Figure 3.

Hallmarks of the apoptotic and necrotic cell-death process. Modified from [23].

2.1. Pathways of apoptosis

Apoptosis consists of two major pathways: extrinsic pathway and intrinsic (mitochondrial) pathway.

2.1.1. Extrinsic pathway

“Death receptors” transmit apoptotic signals after ligation with specific ligands in extrinsic pathway. Death receptors belong to a superfamily, including TNFR-1, Fas/CD95, and the TRAIL receptors DR-4 and DR-5 [24]. Caspase-8 is the hallmark of this pathway. It is activated by a complex named death-inducing-signaling complex (DISC). Activated death receptor recruited adapter molecules like FADD (Fas-associated protein with death domain) or TRADD (tumor necrosis factor receptor type 1-associated DEATH domain). These adapter molecules form the DISC (Figure 4). Caspase-8 then cleave and activate other caspases resulting in cell death. These types of cells, which have the capacity to induce such direct and mainly caspase-dependent apoptosis pathways, were classified to type I cells [25].

Figure 4.

Receptor-mediated caspase activation at the DISC [26].

2.1.2. Intrinsic pathway

In this pathway, the signal does not come from death receptors. In this case, the signal amplified via mitochondria-dependent apoptotic pathways. Bcl-2 family member, Bid, is cleaved by caspase-8 (tBid) and translocates to the mitochondria. tBid in concert with the proapoptotic Bcl-2 family members Bax (Bcl-2-associated x) and Bak (Bcl-2 homologous antagonist/killer) induces the release of cytochrome C and other mitochondrial proapoptotic factors into the cytosol [27].

Cytosolic cytochrome C binds to monomeric Apaf-1 (apoptotic protease-activating factor 1) which then oligomerizes to assemble the apoptosome that triggers the activation of the initiator procaspase-9 [28]. Caspase-9 is the hallmark of intrinsic pathway. Activated caspase-9 ultimately results in cell death by subsequently initiating a caspase cascade involving downstream effector caspases such as caspase-3, caspase-7, and caspase-6 (Figure 5) [29].

Figure 5.

Intrinsic pathway of apoptosis [28].

2.2. Apoptotic pathway proteins

2.2.1. Caspases are central initiators and executioners of apoptosis

The term caspase is derived from cysteine-dependent aspartate-specific proteases. So far, seven different caspases have been identified in Drosophila, and 14 different members of the caspase-family have been described in mammals, with caspase-11 and caspase-12 only identified in the mouse [30, 31]. According to a unified nomenclature, the caspases are referred to in the order of their publication: caspase-1 is ICE (interleukin-1β-converting enzyme), the first mammalian caspase [32, 33]. There are many documents about the importance of caspases in apoptosis phenomenon. For example, it has been shown that caspase-1, -4, -5, -11, and -12 are involved in the maturation of pro-inflammatory cytokines such as pro-IL-1β and pro-IL-18 [31] or studies show that caspase-3 and -9 have a role in brain development [34, 35].

Caspases are synthesized as inactive zymogens, the so-called procaspases. Upon maturation, the procaspases are proteolytically processed. The proapoptotic caspases can be divided into the group of initiator caspases including procaspases-2, -8, -9, and -10, and into the group of executioner caspases including procaspases-3, -6, and -7 [26]. As mentioned earlier, in extrinsic apoptosis pathways procaspase-8 is the hallmark of this pathway. In return of caspase-8, caspase-9 is the hallmark of intrinsic pathway. Once the initiator caspases have been activated, they can proteolytically activate the effector procaspases-3, -6, and -7. Effector caspases subsequently cleave a specific set of protein substrates, resulting in the mediation and amplification of the death signal and eventually in the execution of cell death [36].

2.2.2. The Bcl-2 superfamily

Bcl-2 is an oncogene which was the first example of an oncogene that inhibits cell death rather than promoting proliferation. Bcl-2 family of proteins can be defined by the presence of conserved sequence motifs known as Bcl-2 homology domains (BH1 to BH4). Bcl-2 proteins divided to a group of prosurvival members and others to a group of proapoptotic members [37]. Prosurvival proteins include Bcl-2 itself, Bcl-XL, Bcl-w, A1, and Mcl-1, all of which possess the domains BH1, BH2, BH3, and BH4. The proapoptotic group of Bcl-2 members can be divided into two subgroups: the Bax-subfamily consists of Bax, Bak, and Bok, all of which possess the domains BH1, BH2, and BH3. There is another group of proteins named the BH3-only proteins (Bid, Bim, Bik, Bad, Bmf, Hrk, Noxa, Puma, Blk, BNIP3, and Spike) that have only the short BH3 motif, an interaction domain that is both necessary and sufficient for their killing action [38, 39].

Despite the existence of two hypotheses regarding how the Bcl-2 family controls apoptosis, it seems that the central function of mammalian Bcl-2 family members is to guard mitochondrial integrity and control the release of mitochondrial proteins into the cytoplasm [39]. Another hypothesis is that Bcl-2 members might directly control caspase activation [40]. The question is how mitochondrial integrity is affected by proapoptotic Bcl-2 family members? Central to this question are Bax and Bak. The double knockout of Bax and Bak resulted in dramatic impairment of apoptosis during development in many tissues with superfluous cells accumulating in the hematopoietic system and in the brain [26].

BH3-only members function upstream of Bax and Bak. It is shown that members of the BH3-only subfamily are required for the activation of proapoptotic Bax/Bak function. But it should be noted that prosurvival members Bcl-2 and Bcl-XL have a role in this way [41].

In summary, as it is shown in Figure 6, in a viable cell antiapoptotic proteins like Bcl-2 antagonize Bax/Bak. In response to an apoptotic stimulus, BH3-only proteins are activated. Activated BH3-only proteins prevent antiapoptotic Bcl-2 members from inhibiting proapoptotic members. Therefore, Bax/Bak are activated and form pores in the mitochondrial membrane. In consequence, cytochrome C and other proapoptotic factors are released from the inner mitochondrial membrane into the cytosol. They cause the formation of the apoptosome and the subsequent activation of the caspase cascade [26].

Figure 6.

Regulation of apoptosis by the Bcl-2 family [26].

2.3. Mcl-1 and CLL

Mcl-1 is one of the Bcl-2-related survival proteins but is somewhat structurally distinct and probably lacks a “classical” BH4 domain. It was first discovered in differentiating myeloid cells where Mcl-1 is thought to play a transient role in promoting cell survival, but it has been expressed in various malignant cells, like CLL. Overexpression of Mcl-1 in CLL cells associated with a failure to achieve complete remission following cytotoxic therapy [42].

Mcl-1 protein has a rapid turnover, and it has a short half-life (a few hours). Mcl-1 has a critical role in regulating apoptosis in response to rapidly changing environmental cues. During apoptosis, Mcl-1 is a very efficient substrate for caspases [43, 44, 45, 46]. While Mcl-1 is an antiapoptotic protein, its cleavage by caspases converts it into a cell-death-promoting molecule [43]. Therefore, Mcl-1 can act as a molecular bodyguard or assassin during apoptosis [47]. Saxena et al. showed that Mcl-1 can play an important role in CLL, by insertion of small sequences in its promoter [47]. They showed the presence of specific insertions in 29% patients with CLL and while in none of the controls. They found that these insertions were correlated with rapid disease progression, with a poor response to chemotherapy and shorter disease-specific survival. By founding of insertions in CD38-negative patients, they suggest that a poor prognostic marker [47] can be present.

Finally, since specific genetic targets are not defined in CLL, Mcl-1 seems to be an appropriate biomolecule to therapeutically manipulate. Mcl-1 protein production and maintenance are dependent on several pathways. At the apical level, the microenvironment provides factors that dramatically increase this protein in CLL cells [48]. Hence, a strategy that interferes with the interaction of microenvironment and CLL cells is a logical approach. Production of Mcl-1 through these signals is carried via increased transcription of the Mcl-1 gene. Transcription and polyadenylation inhibition, albeit not selective, is an approach that works because of AU-rich elements in the transcript of Mcl-1, which leads to its rapid turnover [49]. The N-terminal region of Mcl-1 protein contains 2PEST domains that are rich in proline, glutamic acid, serine, and threonine residues, resulting in a short half-life of the protein [49] and making translation inhibition and rapid degradation of endogenous Mcl-1 via proteasome pathway a viable option to reduce the protein level [50]. Mcl-1 is also essential during early lymphoid development [51] and is abundantly expressed in the germinal center B-cell compartment. Pim kinase and Akt-PI3-kinase pathways and downstream of BLyS have been identified to maintain the Mcl-1 levels in B-cells [52]. The roles of these pathways and consequence of their perturbations need to be investigated in malignant lymphocytes. Similarly, work is needed on posttranslational modification leading to increased or decreased half-life of Mcl-1 protein. Finally, and probably most intriguingly, small molecule antagonists of Mcl-1 protein that bind to the BH3 domain releasing proapoptotic proteins provide a new avenue of research and therapeutics.


3. Coumarins

Coumarins (2H-1-benzopyran-2-one) consist of a large class of phenolic substances found in plants and all of which consist of a benzene ring joined to a pyrone ring. More than 1300 coumarins have been identified as secondary metabolites from plants, bacteria, and fungi. The prototypical compound is known as 1,2 benzopyrone or, less commonly, as 𝑜-hydroxycinnamic acid and lactone. Coumarins were initially extracted in tonka bean (Dipteryx odorata Wild) and are reported in about 150 different species distributed over nearly 30 different families, of which a few important ones are Rutaceae, Umbelliferae (Apiaceae), Clusiaceae, Guttiferae, Caprifoliaceae, Oleaceae, and Nyctaginaceae [53]. They are found at high levels in some essential oils, particularly in cinnamon bark oil, cassia leaf oil, and lavender oil. Coumarin is also found in fruits (e.g., bilberry and cloudberry), green tea, and other foods such as chicory. The richest sources of most coumarins among the higher plants are Rutaceae and Umbelliferone. The coumarins occur at the highest levels in the fruits, followed by the roots, stems, and leaves although they are distributed throughout all parts of the plant. Environmental conditions and seasonal changes can influence the occurrence in diverse parts of the plant [54].

3.1. Classification

Based on the chemical structure of their compounds, natural coumarins are classified into six groups (Table 1).

Table 1.

Classification of natural coumarins based on their chemical structure.

Coumarin and its derivatives are principal oral anticoagulants. Coumarin is water insoluble; however, 4-hydroxy substitution confers weakly acidic properties to the molecule that makes it water soluble under slightly alkaline conditions (Figure 7) [54].

Figure 7.

4-hydroxy substitution of coumarin makes it water soluble in alkaline conditions.

The structure of coumarin nucleus (Figure 8) mimics A and B rings of the steroid hormone and binds to the aromatase-binding site with a superior affinity. Upon tactically extending the structure to the tricyclic system, it mimics the steroid hormones that act as SERM/SERD (selective estrogen receptor modulator/selective estrogen receptor downregulator) and thus enhancing the receptor interaction, leading to a development of a potent pharmacophore. 17b-HSD3 (17b-hydroxysteroid dehydrogenase type3), cell division cycle protein, and NF-kB inhibitory activity are potentiated by structural extension with sulfur linked at the C-4 position [55]. It has also been shown that the anticancer activity of coumarins is potentiated by the substitution of imidazole, 1,2,3-triazol, piperidine purine, benzothiazole, substituted phenyl ring, aryl acrylic acid, and chalcone at the fourth position of coumarin nucleus by a linker such as methylene and oxygen [55].

Figure 8.

Structure of simple coumarin.

3.2. Coumarins and leukemia

Induction of apoptosis in leukemic cell lines by coumarins and their derivatives is demonstrated in different in vitro studies. Coumarin compounds have antiproliferative and/or cytotoxic activity on cancer cells, depending on their substitution pattern [56, 57, 58]. It is shown that while long alkyl substitution at C7 position increased the cytotoxic activity against the leukemia cancer cell lines [59], the presence of two hydroxyl groups at C7 and C8 positions seems to improve the potency of methylcoumarins as cytotoxic agents. It is also shown that among 7,8-DHMC (dihydroxy-4-methylcoumarin) derivatives, the longer the C3 alkyl chain, the higher was the activity. This effect of the alkyl group on the cytotoxicity is presumably due to the enhanced lipophilicity of the longer alkyl chains that consequently enhances cell membrane penetration ability of the test compounds. Bromo groups substituted at C4 and C6 positions for DHMCs increased the cytotoxic activity in all the cell lines (Figure 9A) [60]. In another study, it was shown that 7-hydroxycoumarin analog containing carboxymethyl ester group on cinnamoyl moiety (Figure 9B) showed good antiproliferative activity against leukemic cell lines [61]. It is worth noting that the cinnamoyl moiety at C3 is more effective than alkyl chain moiety for increased cytotoxic effect against leukemic cell line K562 (IC50 = 4.4 μM vs. 40.8 μM).

Figure 9.

R2 is 4-(COOMe).

Moreover, studies showed that molecular hybridization of coumarins increased their cytotoxicity against leukemic cell lines. For example, the hybrids with ortho-dihydroxy groups or ortho-hydroxy-methoxy group on the aromatic A ring exhibit superior antiproliferative activity in comparison with those with such groups on the aromatic B ring. Specially, a new hybrid, 6-methoxy-7-hydroxy-3-(4`-hydroxyphenyl)coumarin, emerged as an important lead compound with excellent antiproliferative, apoptosis-inducing, and cell cycle arrest activities against HL-60 cell line (IC50 = 5.2 ± 0.6 μM) (Figure 10) [62].

Figure 10.

6-methoxy-7-hydroxy-3-(4` hydroxyphenyl)coumarin) as a new hybrid.

Paul et al. showed that the synthesis of new conjugated coumarin-benzimidazole hybrids displayed appreciable antileukemic activities in vitro. They showed that the introduction of ethanolamine at position 7 of coumarin-benzimidazole hybrid (Figure 11) shows higher selectivity against leukemia cancer cells (CCRF-CEM, HL-60(TB), K-562, and RPMI-8226) [63].

Figure 11.

NR1R2 is ethanolamine.

Other studies showed that hydrazide-hydrazone (─CO─NH─N═CH─) moiety and acrylohydrazide hybrid at position 3 could increase the cytotoxicity against leukemic cell lines (Figure 12) [64, 65].

Figure 12.

hydrazide-hydrazone moiety and acrylohydrazide hybrid of coumarin.

In other studies, it has been shown that the copper complexes with coumarin derivatives could increase the antileukemic effect of coumarin in vitro (Figure 13).

Figure 13.

Copper complexes with coumarin.

Specifically, in some studies, the significant inhibitory activity of certain coumarins on the proliferation of leukemic cell lines [58, 66, 67, 68] has been reported. In addition, it has been described that such inhibitory effects could be related to either differentiating [58, 66] or proapoptotic activities [67, 68] of the compounds, depending on the distribution of their substituents in the coumarin ring.

Kim and colleagues studied the antileukemic effects of decursin (a pyranocoumarin from Angelica gigas) and its derivatives (Figure 14) on K562 and U937 cell lines. They studied the ability of these compounds as a tumor-suppressing PKC activator and as an antagonist to phorbol 12-myristate 13-acetate (PMA), a tumor-promoting PKC activator. Based on their results, the structure-activity relationship of decursin and its derivatives is as follows: (i) the coumarin structure is required for antileukemic activity and (ii) the side chain is a determinant of PKC activation and the cytotoxic mechanism in leukemia cells [69].

Figure 14.

Structures of decursin (1) and its derivatives 2–12.

In another study, Ahn et al. showed the apoptosis induction by decursin in leukemic KBM-5 cells. They showed that decursin activates caspases 9 and 3 and PARP in KBM-5 cells. They also reported that decursin induced apoptosis via downregulation of COX-2-dependent survivin pathway in KBM-5 myeloid leukemia. In KBM-5 cells, it was reported that targeting survivin could overcome the resistance against imatinib [70].

Esculetin (Figure 15) is a simple coumarin found in some traditional medicines. Induction of apoptosis in various leukemic cell lines was shown in different studies. Chu and their colleagues are one of the first teams that reported the antileukemic effects of esculetin. They showed that esculetin inhibits the survival of human promyelocytic leukemia HL-60 cells in a concentration-dependent and time-dependent manner. Esculetin induced the release of cytochrome C from mitochondria into cytosol, reduced Bcl-2 protein expression, and increased caspase activation [71].

Figure 15.

Structure of esculetin.

Esculetin is a cell cycle-specific antineoplastic agent. It can inhibit the growth of HL-60 and U937 leukemic cells by G1 cell cycle arrest [72, 73]. It also leads to the release of cytochrome C, activation of caspases 3, 8, and 9, downregulation of Bcl-2 protein, and increased the phosphorylation of MEK/ERK and JNK [74, 75, 76, 77].

Tung et al. fractionated and chemically investigated the methanol extract of Mammea siamensis flower, an evergreen tree belonging to the family of Calophyllaceae, and distributed throughout Thailand, Myanmar, Laos, Cambodia, and Vietnam. They isolated and identified eight compounds. Among the isolated compounds, three structurally related coumarins kayeassamin A (Figure 16), surangin C, and theraphin B showed significant antiproliferative activity against human leukemia HL-60 cells. Activation of caspases 3 and 8 and sub-G1 arrest by kayeassamin A have been shown in this study and another one [78, 79].

Figure 16.

Structure of kayeassamin A.

Osthole (Figure 17) is another coumarin where its antileukemic effect has been investigated. It has been shown that osthole has the strongest cytotoxic activity among the coumarins extracted from Cnidii monnieri Fructus on HL-60 cell line. The structure-activity relationship established from the results indicated that the prenyl group has an important role in the cytotoxic effects and apoptosis induction [80].

Figure 17.

Structure of osthole (A) and imperatorin (B).

In another study, osthole could increase intracellular drug accumulation, decreased the expression of multidrug resistance gene 1 (MDR1), and could suppress P-gp expression by inhibiting the PI3K/Akt-signaling pathway in myelogenous leukemia K562/ADM cells [81].

Imperatorin, a biologically active furanocoumarin, is another coumarin that is extracted from Cnidii monnieri Fructus also showed cytotoxic effect against leukemic cell lines [82, 83, 84, 85].

Toddaculin (Figure 18) is another important coumarin where its antileukemic effect is revealed. Vazquez et al. found that toddaculin was the most potent cytotoxic agent among the series of six prenylated coumarins isolated from the stem bark of Toddalia asiatica (Rutaceae). They found that while toddaculin at 250 μM (IC50 = 51.38 ± 4.39) was able to induce apoptosis in U-937 cells, involving decreased phosphorylation levels of ERK and Akt, 50 μM toddaculin exerted differentiating effects [86].

Figure 18.

Structure of toddaculin.

Umbelliprenin (Figure 19) is a prenylated coumarin found in Ferula species. Its antileukemic effect was first reported by Gholami and his colleagues. They found that umbelliprenin has cytotoxic and proapoptotic effects on Jurkat and Raji cell lines. They showed that umbelliprenin activates intrinsic and extrinsic pathways of apoptosis by the activation of caspase-8 and -9, respectively. Inhibition of Bcl-2 was also shown [87, 88].

Figure 19.

Structure of umbelliprenin.

Auraptene (Figure 20) is another coumarin that has a structure close to that of umbelliprenin. The difference between the chemical structures of these compounds is that the length of the 7-prenyloxy chain of umbelliprenin is longer and contains 15 instead of 10 carbons. Apoptogenic activity of auraptene on jurkat cells was shown in detail. Apoptotic effect of auraptene on Jurkat T-cells was exerted by the ER stress-mediated activation of caspase-8 and the subsequent induction of mitochondria-dependent or -independent activation of caspase cascade, which could be suppressed by Bcl-xL [89].

Figure 20.

Structure of auraptene.

3.3. Mcl-1 and coumarins

Coumarins can regulate the expression of Mcl-1. Their regulation is time- and dose-dependent. The regulation of Mcl-1 expression by auraptene, umbelliprenin, imperatorin, galbanic acid, and gut-70 was studied.

Gholami et al. studied and compared the expression of Mcl-1 gene after the Jurkat cells were incubated by umbelliprenin and auraptene. They showed that umbelliprenin increased the expression of Mcl-1 mRNA from 1 to 3 h of incubation, but this increase has a scale-down pattern. Auraptene decreased the expression of Mcl-1 mRNA for the same incubation times [90, 91]. This pattern is similar for Mcl-1 protein expression [91, 92].

Another natural coumarin where its effect on Mcl-1 expression was studied is galbanic acid (Figure 21). Galbanic acid downregulates the Mcl-1 protein expression dose dependently [93]. Imperatorin (Figure 17B), another natural coumarin like galbanic acid, decreased Mcl-1 protein level in a dose-dependent manner [94].

Figure 21.

Galbanic acid.

GUT-70 (Figure 22), a tricyclic coumarin derived from Calophyllum brasiliense, causes Mcl-1 protein upregulation in mantle cell lymphoma (MCL) cell lines [95].

Figure 22.


The effect of synthetic coumarins (RKS262, 5,7-dihydroxy-4-methyl-6-(3-methylbutanoyl)-coumarin (DMAC), and 4-arylcoumarin analogs of combretastatin (Figure 23)) on Mcl-1 protein expression was studied. All of these compounds downregulate Mcl-1 protein dose- and time- dependently [96, 97, 98].

Figure 23.

(A) RKS262, (B) DMAC, and (C) 4-arylcoumarin analogs of combretastatin.


4. Conclusion

In conclusion, coumarins are one of the important cytotoxic agents. They could induce apoptosis and regulate Mcl-1 expression in CLL cell lines. We hope that they be one of the candidates for chemotherapy of CLL in the future.


  1. 1. Rai R, Stilgenbauer, S. Overview of the Treatment of Chronic Lymphocytic Leukemia. 2017. Available from:
  2. 2. Rai KR. Progress in chronic lymphocytic leukaemia: A historical perspective. Bailliere's Clinical Haematology. 1993 Dec;6(4):757-765. PubMed PMID: 8038488
  3. 3. Hallek M, Cheson BD, Catovsky D, Caligaris-Cappio F, Dighiero G, Dohner H, et al. Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines. Blood. 2008 Jun 15;111(12):5446-5456. PubMed PMID: 18216293. Pubmed Central PMCID: 2972576
  4. 4. Stevenson FK, Caligaris-Cappio F. Chronic lymphocytic leukemia: revelations from the B-cell receptor. Blood. 2004 Jun 15;103(12):4389-4395. PubMed PMID: 14962897
  5. 5. Cheson BD, Bennett JM, Grever M, Kay N, Keating MJ, O'Brien S, et al. National Cancer Institute-sponsored Working Group guidelines for chronic lymphocytic leukemia: Revised guidelines for diagnosis and treatment. Blood. 1996 Jun 15;87(12):4990-4997. PubMed PMID: 8652811
  6. 6. Fournier S, Delespesse G, Rubio M, Biron G, Sarfati M. CD23 antigen regulation and signaling in chronic lymphocytic leukemia. The Journal of Clinical Investigation. 1992 Apr;89(4):1312-1321. PubMed PMID: 1532590. Pubmed Central PMCID: 442993
  7. 7. Geisler CH, Larsen JK, Hansen NE, Hansen MM, Christensen BE, Lund B, et al. Prognostic importance of flow cytometric immunophenotyping of 540 consecutive patients with B-cell chronic lymphocytic leukemia. Blood. 1991 Oct 01;78(7):1795-1802. PubMed PMID: 1717071
  8. 8. Grubor V, Krasnitz A, Troge JE, Meth JL, Lakshmi B, Kendall JT, et al. Novel genomic alterations and clonal evolution in chronic lymphocytic leukemia revealed by representational oligonucleotide microarray analysis (ROMA). Blood. 2009 Feb 05;113(6):1294-1303. PubMed PMID: 18922857
  9. 9. Quesada V, Conde L, Villamor N, Ordonez GR, Jares P, Bassaganyas L, et al. Exome sequencing identifies recurrent mutations of the splicing factor SF3B1 gene in chronic lymphocytic leukemia. Nature Genetics. 2011 Dec 11;44(1):47-52. PubMed PMID: 22158541
  10. 10. Faguet GB. Chronic Lymphocytic Leukemia: Molecular Genetics, Biology, Diagnosis, and Management. New Jersey: Humana Press; 2004
  11. 11. Contri A, Brunati AM, Trentin L, Cabrelle A, Miorin M, Cesaro L, et al. Chronic lymphocytic leukemia B-cells contain anomalous Lyn tyrosine kinase, a putative contribution to defective apoptosis. The Journal of Clinical Investigation. 2005 Feb;115(2):369-378. PubMed PMID: 15650771. Pubmed Central PMCID: 544036
  12. 12. Longo PG, Laurenti L, Gobessi S, Sica S, Leone G, Efremov DG. The Akt/Mcl-1 pathway plays a prominent role in mediating antiapoptotic signals downstream of the B-cell receptor in chronic lymphocytic leukemia B cells. Blood. 2008 Jan 15;111(2):846-855. PubMed PMID: 17928528
  13. 13. Fujimoto M, Poe JC, Jansen PJ, Sato S, Tedder TF. CD19 amplifies B lymphocyte signal transduction by regulating Src-family protein tyrosine kinase activation. Journal of Immunology. 1999 Jun 15;162(12):7088-7094. PubMed PMID: 10358152
  14. 14. Gobessi S, Laurenti L, Longo PG, Sica S, Leone G, Efremov DG. ZAP-70 enhances B-cell-receptor signaling despite absent or inefficient tyrosine kinase activation in chronic lymphocytic leukemia and lymphoma B cells. Blood. 2007 Mar 01;109(5):2032-2039. PubMed PMID: 17038529
  15. 15. Pleyer L, Egle A, Hartmann TN, Greil R. Molecular and cellular mechanisms of CLL: Novel therapeutic approaches. Nature Reviews. Clinical Oncology. 2009 Jul;6(7):405-418. PubMed PMID: 19488076
  16. 16. Carlo-Stella C, Lavazza C, Locatelli A, Vigano L, Gianni AM, Gianni L. Targeting TRAIL agonistic receptors for cancer therapy. Clinical Cancer Research: An Official Journal of the American Association for Cancer Research. 2007 Apr 15;13(8):2313-2317. PubMed PMID: 17438088
  17. 17. Adams JM, Cory S. Bcl-2-regulated apoptosis: mechanism and therapeutic potential. Current Opinion in Immunology. 2007 Oct;19(5):488-496. PubMed PMID: 17629468. Pubmed Central PMCID: 2754308
  18. 18. Mackus WJ, Kater AP, Grummels A, Evers LM, Hooijbrink B, Kramer MH, et al. Chronic lymphocytic leukemia cells display p53-dependent drug-induced Puma upregulation. Leukemia. 2005 Mar;19(3):427-434. PubMed PMID: 15674362
  19. 19. Villunger A, Michalak EM, Coultas L, Mullauer F, Bock G, Ausserlechner MJ, et al. p53- and drug-induced apoptotic responses mediated by BH3-only proteins puma and noxa. Science. 2003 Nov 07;302(5647):1036-1038. PubMed PMID: 14500851
  20. 20. Yin XM, Wang K, Gross A, Zhao Y, Zinkel S, Klocke B, et al. Bid-deficient mice are resistant to Fas-induced hepatocellular apoptosis. Nature. 1999 Aug 26;400(6747):886-891. PubMed PMID: 10476969
  21. 21. Dicker F, Kater AP, Prada CE, Fukuda T, Castro JE, Sun G, et al. CD154 induces p73 to overcome the resistance to apoptosis of chronic lymphocytic leukemia cells lacking functional p53. Blood. 2006 Nov 15;108(10):3450-3457. PubMed PMID: 16741250. Pubmed Central PMCID: 1895435
  22. 22. Dash P. Apoptosis2001. pp. 1-6. Available from:
  23. 23. Van Cruchten S, Van Den Brook W. Morphological and biochemical aspects of apoptosis, oncosis and necrosis. Anat Histol Embryol. 2002;31(4):214-223
  24. 24. Ashkenazi A. Targeting death and decoy receptors of the tumour-necrosis factor superfamily. Nature Reviews Cancer. 2002 Jun;2(6):420-430. PubMed PMID: 12189384
  25. 25. Scaffidi C, Fulda S, Srinivasan A, Friesen C, Li F, Tomaselli KJ, et al. Two CD95 (APO-1/Fas) signaling pathways. The EMBO Journal. 1998 Mar 16;17(6):1675-1687. PubMed PMID: 9501089. Pubmed Central PMCID: 1170515
  26. 26. Gewies A. Introduction to Apoptosis2003. pp. 1-26. Available from:
  27. 27. Luo X, Budihardjo I, Zou H, Slaughter C, Wang X. Bid, a Bcl2 interacting protein, mediates cytochrome c release from mitochondria in response to activation of cell surface death receptors. Cell. 1998 Aug 21;94(4):481-490. PubMed PMID: 9727491
  28. 28. Acehan D, Jiang X, Morgan DG, Heuser JE, Wang X, Akey CW. Three-dimensional structure of the apoptosome: Implications for assembly, procaspase-9 binding, and activation. Molecular Cell. 2002 Feb;9(2):423-432. PubMed PMID: 11864614
  29. 29. Slee EA, Harte MT, Kluck RM, Wolf BB, Casiano CA, Newmeyer DD, et al. Ordering the cytochrome c-initiated caspase cascade: hierarchical activation of caspases-2, -3, -6, -7, -8, and -10 in a caspase-9-dependent manner. The Journal of Cell Biology. 1999 Jan 25;144(2):281-292. PubMed PMID: 9922454. Pubmed Central PMCID: 2132895
  30. 30. Richardson H, Kumar S. Death to flies: Drosophila as a model system to study programmed cell death. Journal of Immunological Methods. 2002 Jul 01;265(1-2):21-38. PubMed PMID: 12072176
  31. 31. Denault JB, Salvesen GS. Caspases: Keys in the ignition of cell death. Chemical Reviews. 2002 Dec;102(12):4489-4500. PubMed PMID: 12475198
  32. 32. Creagh EM, Martin SJ. Caspases: cellular demolition experts. Biochemical Society Transactions. 2001 Nov;29(Pt 6):696-702. PubMed PMID: 11709057
  33. 33. Miura M, Zhu H, Rotello R, Hartwieg EA, Yuan J. Induction of apoptosis in fibroblasts by IL-1 beta-converting enzyme, a mammalian homolog of the C. elegans cell death gene ced-3. Cell. 1993 Nov 19;75(4):653-660. PubMed PMID: 8242741
  34. 34. Kuida K, Haydar TF, Kuan CY, Gu Y, Taya C, Karasuyama H, et al. Reduced apoptosis and cytochrome c-mediated caspase activation in mice lacking caspase 9. Cell. 1998 Aug 07;94(3):325-337. PubMed PMID: 9708735
  35. 35. Kuida K, Zheng TS, Na S, Kuan C, Yang D, Karasuyama H, et al. Decreased apoptosis in the brain and premature lethality in CPP32-deficient mice. Nature. 1996 Nov 28;384(6607):368-372. PubMed PMID: 8934524
  36. 36. Earnshaw WC, Martins LM, Kaufmann SH. Mammalian caspases: structure, activation, substrates, and functions during apoptosis. Annual Review of Biochemistry. 1999;68:383-424. PubMed PMID: 10872455
  37. 37. Borner C. The Bcl-2 protein family: sensors and checkpoints for life-or-death decisions. Molecular Immunology. 2003 Jan;39(11):615-647. PubMed PMID: 12493639
  38. 38. Mund T, Gewies A, Schoenfeld N, Bauer MK, Grimm S. Spike, a novel BH3-only protein, regulates apoptosis at the endoplasmic reticulum. FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology. 2003 Apr;17(6):696-698. PubMed PMID: 12594175
  39. 39. Cory S, Adams JM. The Bcl2 family: Regulators of the cellular life-or-death switch. Nature Reviews Cancer. 2002 Sep;2(9):647-656. PubMed PMID: 12209154
  40. 40. Strasser A, O'Connor L, Dixit VM. Apoptosis signaling. Annual Review of Biochemistry. 2000;69:217-245. PubMed PMID: 10966458
  41. 41. Bouillet P, Strasser A. BH3-only proteins—Evolutionarily conserved proapoptotic Bcl-2 family members essential for initiating programmed cell death. Journal of Cell Science. 2002 Apr 15;115(Pt 8):1567-1574. PubMed PMID: 11950875
  42. 42. Saxena A, Viswanathan S, Moshynska O, Tandon P, Sankaran K, Sheridan DP. Mcl-1 and Bcl-2/Bax ratio are associated with treatment response but not with Rai stage in B-cell chronic lymphocytic leukemia. American Journal of Hematology. 2004 Jan;75(1):22-33. PubMed PMID: 14695629
  43. 43. Michels J, Johnson PW, Packham G. Mcl-1. The International Journal of Biochemistry & Cell Biology. 2005 Feb;37(2):267-271. PubMed PMID: 15474972
  44. 44. Clohessy JG, Zhuang J, Brady HJ. Characterisation of Mcl-1 cleavage during apoptosis of haematopoietic cells. British Journal of Haematology. 2004 Jun;125(5):655-665. PubMed PMID:15147382
  45. 45. Snowden RT, Sun XM, Dyer MJ, Cohen GM. Bisindolylmaleimide IX is a potent inducer of apoptosis in chronic lymphocytic leukaemic cells and activates cleavage of Mcl-1. Leukemia. 2003 Oct;17(10):1981-1989. PubMed PMID: 14513048
  46. 46. Herrant M, Luciano F, Loubat A, Auberger P. The protective effect of phorbol esters on Fas-mediated apoptosis in T cells. Transcriptional and posttranscriptional regulation. Oncogene. 2002 Jul 25;21(32):4957-4968. PubMed PMID: 12118374
  47. 47. Packham G, Stevenson FK. Bodyguards and assassins: Bcl-2 family proteins and apoptosis control in chronic lymphocytic leukaemia. Immunology. 2005 Apr;114(4):441-449. PubMed PMID: 15804279. Pubmed Central PMCID: 1782118
  48. 48. Burger JA, Kipps TJ. CXCR4: A key receptor in the crosstalk between tumor cells and their microenvironment. Blood. 2006 Mar 01;107(5):1761-1767. PubMed PMID:16269611
  49. 49. Chen R, Keating MJ, Gandhi V, Plunkett W. Transcription inhibition by flavopiridol: Mechanism of chronic lymphocytic leukemia cell death. Blood. 2005 Oct 01;106(7):2513-2519. PubMed PMID: 15972445. Pubmed Central PMCID: 1895272
  50. 50. Maurer U, Charvet C, Wagman AS, Dejardin E, Green DR. Glycogen synthase kinase-3 regulates mitochondrial outer membrane permeabilization and apoptosis by destabilization of MCL-1. Molecular Cell. 2006 Mar 17;21(6):749-760. PubMed PMID: 16543145
  51. 51. Opferman JT, Letai A, Beard C, Sorcinelli MD, Ong CC, Korsmeyer SJ. Development and maintenance of B and T lymphocytes requires antiapoptotic MCL-1. Nature. 2003 Dec 11;426(6967):671-676. PubMed PMID: 14668867
  52. 52. Woodland RT, Fox CJ, Schmidt MR, Hammerman PS, Opferman JT, Korsmeyer SJ, et al. Multiple signaling pathways promote B lymphocyte stimulator dependent B-cell growth and survival. Blood. 2008 Jan 15;111(2):750-760. PubMed PMID: 17942753. Pubmed Central PMCID: 2200845
  53. 53. Venugopala KN, Rashmi V, Odhav B. Review on natural coumarin lead compounds for their pharmacological activity. BioMed Research International. 2013;2013:963248. PubMed PMID: 23586066. Pubmed Central PMCID: 3622347
  54. 54. Jain PK, Joshi H. Coumarin: Chemical and pharmacological profile. Journal of Applied Pharmaceutical Science. 2012;02(06):236-240
  55. 55. Dandriyal J, Singla R, Kumar M, Jaitak V. Recent developments of C-4 substituted coumarin derivatives as anticancer agents. European Journal of Medicinal Chemistry. 2016 Aug 25;119:141-168. PubMed PMID: 27155469
  56. 56. Riveiro ME, De Kimpe N, Moglioni A, Vazquez R, Monczor F, Shayo C, et al. Coumarins: Old compounds with novel promising therapeutic perspectives. Current Medicinal Chemistry. 2010;17(13):1325-1338. PubMed PMID: 20166938
  57. 57. Murata T, Itoigawa M, Ito C, Nakao K, Tsuboi M, Kaneda N, et al. Induction of apoptosis in human leukaemia HL-60 cells by furanone-coumarins from Murraya siamensis. The Journal of Pharmacy and Pharmacology. 2008 Mar;60(3):385-389. PubMed PMID: 18284820
  58. 58. Riveiro ME, Shayo C, Monczor F, Fernandez N, Baldi A, De Kimpe N, et al. Induction of cell differentiation in human leukemia U-937 cells by 5-oxygenated-6,7-methylenedioxycoumarins from Pterocaulon polystachyum. Cancer Letters. 2004 Jul 16;210(2):179-188. PubMed PMID: 15183533
  59. 59. You CX, Yang K, Wang CF, Zhang WJ, Wang Y, Han J, et al. Cytotoxic compounds isolated from Murraya tetramera Huang. Molecules. 2014 Aug 27;19(9):13225-13234. PubMed PMID: 25165861
  60. 60. Miri R, Nejati M, Saso L, Khakdan F, Parshad B, Mathur D, et al. Structure-activity relationship studies of 4-methylcoumarin derivatives as anticancer agents. Pharmaceutical Biology. 2016;54(1):105-110. PubMed PMID: 26017566
  61. 61. Molaverdi F, Khoobi M, Emami S, Alipour M, Firuzi O, Foroumadi A, et al. Polyoxygenated cinnamoylcoumarins as conformationally constrained analogs of cytotoxic diarylpentanoids: Synthesis and biological activity. European Journal of Medicinal Chemistry. 2013 Oct;68:103-110. PubMed PMID: 23973822
  62. 62. Yang J, Liu GY, Dai F, Cao XY, Kang YF, Hu LM, et al. Synthesis and biological evaluation of hydroxylated 3-phenylcoumarins as antioxidants and antiproliferative agents. Bioorganic & Medicinal Chemistry Letters. 2011 Nov 01;21(21):6420-6425. PubMed PMID: 21920747
  63. 63. Paul K, Bindal S, Luxami V. Synthesis of new conjugated coumarin-benzimidazole hybrids and their anticancer activity. Bioorganic & Medicinal Chemistry Letters. 2013 Jun 15;23(12):3667-3672. PubMed PMID: 23642480
  64. 64. Elshemy HA, Zaki MA. Design and synthesis of new coumarin hybrids and insight into their mode of antiproliferative action. Bioorganic & Medicinal Chemistry. 2017 Feb 01;25(3):1066-1075. PubMed PMID: 28038941
  65. 65. Nasr T, Bondock S, Youns M. Anticancer activity of new coumarin substituted hydrazide-hydrazone derivatives. European Journal of Medicinal Chemistry. 2014 Apr 09;76:539-548. PubMed PMID: 24607878
  66. 66. Riveiro ME, Maes D, Vazquez R, Vermeulen M, Mangelinckx S, Jacobs J, et al. Toward establishing structure-activity relationships for oxygenated coumarins as differentiation inducers of promonocytic leukemic cells. Bioorganic & Medicinal Chemistry. 2009 Sep 15;17(18):6547-6559. PubMed PMID: 19716307
  67. 67. Riveiro ME, Vazquez R, Moglioni A, Gomez N, Baldi A, Davio C, et al. Biochemical mechanisms underlying the pro-apoptotic activity of 7,8-dihydroxy-4-methylcoumarin in human leukemic cells. Biochemical Pharmacology. 2008 Feb 01;75(3):725-736. PubMed PMID: 17996847
  68. 68. Riveiro ME, Moglioni A, Vazquez R, Gomez N, Facorro G, Piehl L, et al. Structural insights into hydroxycoumarin-induced apoptosis in U-937 cells. Bioorganic & Medicinal Chemistry. 2008 Mar 01;16(5):2665-2675. PubMed PMID: 18060791
  69. 69. Kim HH, Sik Bang S, Seok Choi J, Han H, Kim IH. Involvement of PKC and ROS in the cytotoxic mechanism of anti-leukemic decursin and its derivatives and their structure-activity relationship in human K562 erythroleukemia and U937 myeloleukemia cells. Cancer Letters. 2005 Jun 08;223(2):191-201. PubMed PMID: 15896453
  70. 70. Ahn Q, Jeong SJ, Lee HJ, Kwon HY, Han I, Kim HS, et al. Inhibition of cyclooxygenase-2-dependent survivin mediates decursin-induced apoptosis in human KBM-5 myeloid leukemia cells. Cancer Letters. 2010 Dec 08;298(2):212-221. PubMed PMID: 20673699. Pubmed Central PMCID: 3689030
  71. 71. Chu CY, Tsai YY, Wang CJ, Lin WL, Tseng TH. Induction of apoptosis by esculetin in human leukemia cells. European Journal of Pharmacology. 2001 Mar 23;416(1-2):25-32. PubMed PMID: 11282109
  72. 72. Lee SH, Park C, Jin CY, Kim GY, Moon SK, Hyun JW, et al. Involvement of extracellular signal-related kinase signaling in esculetin induced G1 arrest of human leukemia U937 cells. Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie. 2008 Dec;62(10):723-729. PubMed PMID: 18222060
  73. 73. Wang CJ, Hsieh YJ, Chu CY, Lin YL, Tseng TH. Inhibition of cell cycle progression in human leukemia HL-60 cells by esculetin. Cancer Letters. 2002 Sep 26;183(2):163-168. PubMed PMID: 12065091
  74. 74. Rubio V, Calvino E, Garcia-Perez A, Herraez A, Diez JC. Human acute promyelocytic leukemia NB4 cells are sensitive to esculetin through induction of an apoptotic mechanism. Chemico-Biological Interactions. 2014 Sep 05;220:129-139. PubMed PMID: 24995577
  75. 75. Park C, Jin CY, Kwon HJ, Hwang HJ, Kim GY, Choi IW, et al. Induction of apoptosis by esculetin in human leukemia U937 cells: Roles of Bcl-2 and extracellular-regulated kinase signaling. Toxicology In Vitro. 2010 Mar;24(2):486-494. PubMed PMID: 19786087
  76. 76. Lin TH, FJ L, Yin YF, Tseng TH. Enhancement of esculetin on arsenic trioxide-provoked apoptosis in human leukemia U937 cells. Chemico-Biological Interactions. 2009 Jun 15;180(1):61-68. PubMed PMID: 19428345
  77. 77. Park C, Jin CY, Kim GY, Choi IW, Kwon TK, Choi BT, et al. Induction of apoptosis by esculetin in human leukemia U937 cells through activation of JNK and ERK. Toxicology and Applied Pharmacology. 2008 Mar 01;227(2):219-228. PubMed PMID: 18031783
  78. 78. Uto T, Tung NH, Thongjankaew P, Lhieochaiphant S, Shoyama Y. Kayeassamin A isolated from the flower of Mammea siamensis triggers apoptosis by activating caspase-3/-8 in HL-60 human leukemia cells. Pharmacognosy Research. 2016 Oct-Dec;8(4):244-248. PubMed PMID: 27695262. Pubmed Central PMCID: 5004513
  79. 79. Tung NH, Uto T, Sakamoto A, Hayashida Y, Hidaka Y, Morinaga O, et al. Antiproliferative and apoptotic effects of compounds from the flower of Mammea siamensis (Miq.) T. Anders. on human cancer cell lines. Bioorganic & Medicinal Chemistry Letters. 2013 Jan 01;23(1):158-162. PubMed PMID: 23206866
  80. 80. Yang LL, Wang MC, Chen LG, Wang CC. Cytotoxic activity of coumarins from the fruits of Cnidium monnieri on leukemia cell lines. Planta Medica. 2003 Dec;69(12):1091-1095. PubMed PMID: 14750023
  81. 81. Wang H, Jia XH, Chen JR, Wang JY, Li YJ. Osthole shows the potential to overcome P-glycoproteinmediated multidrug resistance in human myelogenous leukemia K562/ADM cells by inhibiting the PI3K/Akt signaling pathway. Oncology Reports. 2016 Jun;35(6):3659-3668. PubMed PMID: 27109742
  82. 82. Bhatti R, Singh J, Saxena AK, Suri N, Ishar MP. Pharmacognostic standardisation and antiproliferative activity of Aegle marmelos (L.) Correa leaves in various human cancer cell lines. Indian Journal of Pharmaceutical Sciences. 2013 Nov;75(6):628-634. PubMed PMID: 24591736. Pubmed Central PMCID: 3928725
  83. 83. Appendino G, Bianchi F, Bader A, Campagnuolo C, Fattorusso E, Taglialatela-Scafati O, et al. Coumarins from Opopanax chironium. New dihydrofuranocoumarins and differential induction of apoptosis by imperatorin and heraclenin. Journal of Natural Products. 2004 Apr;67(4):532-536. PubMed PMID: 15104479
  84. 84. Pae HO, Oh H, Yun YG, Oh GS, Jang SI, Hwang KM, et al. Imperatorin, a furanocoumarin from Angelica dahurica (Umbelliferae), induces cytochrome c-dependent apoptosis in human promyelocytic leukaemia, HL-60 Cells. Pharmacology & Toxicology. 2002 Jul;91(1):40-48. PubMed PMID: 12193260
  85. 85. Kawaii S, Tomono Y, Katase E, Ogawa K, Yano M. Effect of coumarins on HL-60 cell differentiation. Anticancer Research. 2000 Jul-Aug;20(4):2505-2512. PubMed PMID: 10953319
  86. 86. Vazquez R, Riveiro ME, Vermeulen M, Mondillo C, Coombes PH, Crouch NR, et al. Toddaculin, a natural coumarin from Toddalia asiatica, induces differentiation and apoptosis in U-937 leukemic cells. Phytomedicine: International Journal of Phytotherapy and Phytopharmacology. 2012 Jun 15;19(8-9):737-746. PubMed PMID: 22537907
  87. 87. Gholami O, Jeddi-Tehrani M, Iranshahi M, Zarnani AH, Ziai SA. Umbelliprenin from Ferula szowitsiana Activates both Intrinsic and Extrinsic Pathways of Apoptosis in Jurkat T-CLL cell line. Iranian Journal of Pharmaceutical Research : IJPR. 2013 Summer;12(3):371-376. PubMed PMID: 24250644. Pubmed Central PMCID: 3813267
  88. 88. Ziai SA, Gholami O, Iranshahi M, Zamani AH, Jeddi-Tehrani M. Umbelliprenin induces apoptosis in CLL cell lines. Iranian Journal of Pharmaceutical Research: IJPR. 2012 Spring;11(2):653-659. PubMed PMID: 24250490. Pubmed Central PMCID: 3832171
  89. 89. Jun DY, Kim JS, Park HS, Han CR, Fang Z, Woo MH, et al. Apoptogenic activity of auraptene of Zanthoxylum schinifolium toward human acute leukemia Jurkat T cells is associated with ER stress-mediated caspase-8 activation that stimulates mitochondria-dependent or -independent caspase cascade. Carcinogenesis. 2007 Jun;28(6):1303-1313. PubMed PMID: 17301064
  90. 90. Motlagh FM, Gholami O. Comparison of umbelliprenin and auraptene in cytotoxic effects and myeloid cell leukaemia type-1 (Mcl-1) gene expression. Indian Journal of Pharmaceutical Sciences. 2016;78(6):827-833
  91. 91. Gholami O, Jeddi-Tehrani M, Iranshahi M, Zarnani AH, Ziai SA. Mcl-1 is up regulated by prenylated coumarin, umbelliprenin in jurkat cells. Iranian Journal of Pharmaceutical Research. 2014 Fall;13(4):1387-1392. PubMed PMID: 25587328. Pubmed Central PMCID: 4232805
  92. 92. Lee JC, Shin EA, Kim B, Kim BI, Chitsazian-Yazdi M, Iranshahi M, et al. Auraptene induces apoptosis via myeloid cell leukemia 1-mediated activation of caspases in PC3 and DU145 prostate cancer cells. Phytotherapy Research. 2017 Jun;31(6):891-898. PubMed PMID: 28383142
  93. 93. BS O, Shin EA, Jung JH, Jung DB, Kim B, Shim BS, et al. Apoptotic effect of galbanic acid via activation of caspases and inhibition of Mcl-1 in H460 non-small lung carcinoma cells. Phytotherapy Research. 2015 Jun;29(6):844-849. PubMed PMID:25753585
  94. 94. Li X, Zeng X, Sun J, Li H, Wu P, Fung KP, et al. Imperatorin induces Mcl-1 degradation to cooperatively trigger Bax translocation and Bak activation to suppress drug-resistant human hepatoma. Cancer Letters. 2014 Jun 28;348(1-2):146-155. PubMed PMID: 24680709
  95. 95. Jin L, Tabe Y, Kimura S, Zhou Y, Kuroda J, Asou H, et al. Antiproliferative and proapoptotic activity of GUT-70 mediated through potent inhibition of Hsp90 in mantle cell lymphoma. British Journal of Cancer. 2011 Jan 04;104(1):91-100. PubMed PMID: 21139584. Pubmed Central PMCID: 3039813
  96. 96. Lin MH, Cheng CH, Chen KC, Lee WT, Wang YF, Xiao CQ, et al. Induction of ROS-independent JNK-activation-mediated apoptosis by a novel coumarin-derivative, DMAC, in human colon cancer cells. Chemico-Biological Interactions. 2014 Jul 25;218:42-49. PubMed PMID: 24812029
  97. 97. Singh RK, Lange TS, Kim KK, Brard L. A coumarin derivative (RKS262) inhibits cell-cycle progression, causes pro-apoptotic signaling and cytotoxicity in ovarian cancer cells. Investigational New Drugs. 2011 Feb;29(1):63-72. PubMed PMID: 19865799. Pubmed Central PMCID: 4801487
  98. 98. Billard C, Menasria F, Quiney C, Faussat AM, Finet JP, Combes S, et al. 4-Arylcoumarin analogues of combretastatins stimulate apoptosis of leukemic cells from chronic lymphocytic leukemia patients. Experimental Hematology. 2008 Dec;36(12):1625-1633. PubMed PMID:18922614


  • B-cell CLL Lymphoma 2.
  • Mitogen-activated protein kinase/extracellular signal-regulated kinase.
  • Phosphatidylinositol-3-kinase and protein kinase B.

Written By

Omid Gholami

Submitted: June 20th, 2017 Reviewed: November 14th, 2017 Published: February 5th, 2018