IP6 + Ins in the Treatment of Colon Cancer Patients during Chemotherapy: Observational Clinical Study

Abstract

Although multiple health-beneficial effects have been related to inositol hexaphosphate (IP6), the most striking is its anticancer effect. This natural, highly phosphorylated carbohydrate and its parent compound, myo-inositol (Ins), are abundantly present in plants, but also in mammalian cells, where they regulate important cellular functions. IP6 reduces proliferation and induces apoptosis and differentiation of malignant cells, enhances immunity, and affects several critical molecular targets. The best results were obtained from the combination of IP6 + Ins. Available as a dietary supplement, IP6 + Ins can enhance the anticancer effect of conventional chemotherapy, and improve quality of life in cancer patients, reducing burden of chemotherapy. Here we present the first, but encouraging, clinical observational study with IP6 and Ins in colon cancer patients during chemotherapy. These results were the basis for several randomized controlled trials organized later. We hope that more clinical trials and mechanistic studies would follow to clarify these intriguing findings.

1. Introduction

Cancer is still rapidly growing, representing one of the major global health problems. Today we know that more than one-half of cancer cases and deaths are potentially preventable by modifications of major risk factors, such as smoking, unhealthy diet, consumption of alcohol, physical inactivity, and overweight and obesity [1]. By increasing vegetable intake, maintaining the optimum body weight and regular physical activity, it has been shown that 30–40% of cancers could be prevented [2, 3], even more, if we can apply the knowledge about cancer prevention, the obstacles are socio-economic reasons.

Globally, colorectal cancer (CRC) is the third most common cancer [4]. It also represents the second leading cause of death related to cancer [4]. It was projected that over 1.9 million new CRC cases and 930,000 deaths will happen in 2020. Estimated to GLOBOCAN, by 2040 there will be 3.2 million new cases of CRC and 1.6 million deaths [4].

However, interestingly, this highly frequent cancer worldwide is largely preventable through changes in modifiable risk factors. Since diet has an important role in the etiology of CRC [4, 5], the use of natural products, that are well tolerated, have been suggested for the prevention and treatment of CRC.

IP6 (myo-inositol hexaphosphate, InsP₆, known also as phytic acid) and its parent compound myo-inositol (Ins) are both found in plants [6, 7, 8]. Because of its unique structure, IP6 is known and accepted as a strong antioxidant [9]. However, not only in plants, but almost all mammalian cells contain IP6 and lower inositol phosphates. These molecules have essential roles in regulating vital cellular functions and activities, energy metabolism, and signal transduction [10, 11, 12].

Here we give a brief overview of the anticancer potential of IP6, and then present the first data in a clinical setting, in patients with colon cancer during chemotherapy. This observational study provided a great basis for later clinical trials.

2. Anticancer potential of IP6

2.1 Cancer preventive and therapeutic activities

The first preclinical studies showing anticancer potential of IP6 in colon cancer were conducted by Shamsuddin et al. [13, 14, 15]. IP6 was given in drinking water to experimental animals and was able to prevent colon cancer using different animal models (rats and mice) and even when using different carcinogens (1,2-dimethylhydrazine and azoxymethane) [13, 14, 15, 16, 17, 18, 19, 20, 21]. IP6 was potent and effective in inhibiting colon cancer in a dose-dependent manner given either before or after carcinogen administration. However, extremely exciting was the finding that IP6 was able to reduce the development of large intestinal cancer even when given after carcinogen administration. This ability of IP6 to significantly lower tumor number and size even 5 months after administration, had suggested its potential use of IP6 as a therapeutic agent [15]. Furthermore, in these first experimental studies with IP6 in colon cancer, other investigators (Drs. Pretlow and Reddy) demonstrated a decreased incidence of aberrant crypts, the parameter that has been often utilized as an intermediate biomarker for colon cancer at that time [18, 19]. A broad-spectrum anticancer activity was shown against cancers of different cells and different tissue systems, where IP6 inhibited growth of malignant cells, induced differentiation in K-562 hematopoietic cells [22], HT-29 cells human colon carcinoma [23, 24], prostate, breast, and rhabdomyosarcoma cancer cells [25] in vitro. Additionally, in vivo experiments showed cancer preventive and protective effects of IP6 in breast cancer [25], skin cancer [26, 27], and prostate cancer [28].

The therapeutic properties of IP6 were shown in the FSA-1 mouse model of transplantable and metastatic fibrosarcoma [29], in human rhabdomyosarcoma [30], and experimental hepatoma model [31]. In a human rhabdomyosarcoma (RD) animal model, RD cells were transplanted in nude mice [30], and the efficacy of IP6 was tested on the tumor-forming capacity of RD cells during the peritumoral treatment with IP6, initiated 2 days after subcutaneous injection of RD cells. In this model, IP6 was able to suppress tumor growth by 25–49-fold [30]. Furthermore, IP6 was also potent to inhibit experimental hepatoma [31, 32], when the efficacy of IP6 was tested on tumorigenicity and on tumor regression. While a single treatment of HepG2 cells in vitro by IP6 resulted in a complete loss of their ability to form tumors when inoculated subcutaneously in nude mice [31], a dramatic regression of liver cancers was demonstrated when tumors were treated directly with IP6 [31].

2.2 Possible mechanisms

It has been hypothesized and then shown in many experimental models that Ins potentiates both the antiproliferative and antineoplastic effects of IP6 in vivo in colon, mammary cancer, and in metastatic lung cancer model [25]. In a series of preclinical experiments Dr. Song Yang was studying colon cancer and its metastasis to the liver [33, 34, 35], also demonstrating that Ins potentiates the anticancer effect of IP6. They showed that when combining IP6 and Ins, the survival of experimental animals was improved, while the tumor mass and liver metastasis were decreased. Because metastasis is a primary cause of death in colon cancer patients, and the liver is the most common site, the work of Dr. Song Yang and his group is very important [33, 34, 35].

Today we better understand the role of IP6, Ins and inositol phosphates, and their involvement in multiple biochemical pathways and cellular interactions. We know that almost all animal cells contain inositol phosphates that affect and regulate multiple cell functions, signal transduction, and energy metabolism. The specific role of IP6 among these multiple signaling pathways is very complex and still needs to be studied in the future. Briefly, IP6 can modulate cellular response at the level of receptor binding, can affect few critical molecular targets in the cell cycle (p27, pRB phosphorylation), signal transduction (PI3K, PKC/RAS/ERK, Akt, ERK), and inflammation (NF-κB). Several broad and extensive reviews of the anticancer activity of IP6 and Ins have been published [25, 36, 37, 38, 39]. In this report, we mentioned briefly some of the most important cellular mechanisms and molecular interaction of IP6 and would like to focus on those important in colon cancer science and clinical applications.

2.3 IP6 in colon cancer

Regarding the anticancer effect of IP6 in colon cancer, a wide range of results starting from the initial aberrant crypt foci, an early biomarker of colon carcinogenesis [25] to the novel regulation of microRNA-155 and its related gene expression [40] have been shown. Very novel are mechanisms related to the anti-metastatic effects of IP6 and Ins in a liver metastasis model of colorectal cancer in BALB/c mice, that involve the changing expression of the extracellular matrix proteins collagen IV, fibronectin, and laminin, the adhesion factor receptor integrin-β1, the proteolytic enzyme matrix metalloproteinase 9, and the angiogenic factors vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor beta in the tumor metastasis microenvironment [33]. Trying to better understand the mechanism of inhibiting tumor progression and liver metastasis of colorectal cancer, Dr. Song’s team utilized an orthotopic transplantation model of colorectal cancer [34] and monitored the expression of genes related to the Wnt/β-catenin in this model. Their results of real-time PCR and Western blot indicated that mRNA and protein expressions of β-catenin, Wnt10b, Tcf7, and c-Myc were significantly lower in IP6 + Ins group [34].

In addition to its role and effects on tumor, IP6 can act on host’s immune system. It was shown that IP6 can boost natural killer cell (NK) activity [41, 42]. Interestingly, the inverse relationship between NK activity and tumor incidence was shown. An increase in cancer incidence is associated with a decreased NK cell activity, while increased NK activity, induced by IP6 is related to decreased tumor incidence.

Furthermore, the sensitivity and selectivity of IP6 were shown, with ability to target malignant cells without affecting normal cells and tissues [25]. Also, IP6 was able to acts synergistically with standard chemotherapeutics and to overcome the acquired drug resistance [25].

3. IP6 + Ins in the treatment of colon cancer patients during chemotherapy: observational clinical study

IP6 + Ins has been available as a supplement for over 20 years. Both IP6 and Ins met specifications of the FDA, and both have been given GRAS (Generally Recognized As Safe) status. As a part of regular diet, both IP6 and Ins have very low toxicity and therefore can be used to enhance the anticancer effect of conventional chemotherapy with almost no, or very few side effects. Here we present observational clinical study of colon cancer patients who were taking IP6 + Ins supplement during chemotherapy. This study has never been published but served as a basis for several, organized clinical studies.

3.1 Methods

In the period from 2000 to 2004, 22 patients with colon cancer stage Dukes B and higher, treated at the University Hospital Split, Croatia were included in the study. All patients were treated with postoperative chemotherapy. Data from preoperative and postoperative evaluation, which included abdominal CT and ultrasound, lung X-ray, complete blood count with differentials, biochemical laboratory tests, tumor markers: CEA, CA 19–9, and pathohistological findings were included in this study. Chemotherapy was administered according to the “Mayo Clinic” protocol, 5 days/6 weeks, with 5-FU 425 mg/m², and Leucovorine 20 mg/m². Radiotherapy was administered in 25 cycles of 2 Gy. IP6 + Ins regimen during chemotherapy was 4 capsules (2040 mg) thrice daily, 30 minutes before meals. Following chemotherapy, the IP6 + Ins regimen was 2 capsules (1020 mg), thrice daily, before meals. Chemotherapy-related side-effects were monitored in all patients, namely: drop in leukocyte and platelet counts, nausea, vomiting, stomatitis, fever, diarrhea, alopecia, and neurological disorders (paraesthesia).

Statistical analysis was performed using t-test, Friedman’s test for finding differences in treatments across multiple attempts, and repeated measures ANOVA. p-value <0.05 was considered significant.

3.2 Results

Out of 22 participants, 16 were males. The average age for male participants was 64 years (41–71), and for females 66 years (54–70). Colon cancer was classified as Dukes B in 8, Dukes C in 10, and Dukes D in 4 participants. The right hemicolectomy was performed in 3 patients, sub-total colectomy in 3, anterior resection of rectum in 12, and amputation of rectum in 4 patients. Laboratory results and their comparison during chemotherapy, at the middle and the end of chemotherapy are shown in Table 1. There were no significant changes in these values during chemotherapy in patients who were receiving IP6 + Ins (t-test).

	Middle of the chemotherapy	End of the chemotherapy	p-value
Hematocrit (L/L)	0.33	0.33	0.15
Platelets (× 10^9/L)	240	231	0.37
AST (U/L)	17.9	19.6	0.47
Creatinine (μmol/L)	94.1	95.5	0.50
BUN (mmol/L)	5.9	6.0	0.68
Glucose (mmol/L)	5.6	5.7	0.58
CEA (ng/mL)	7.3	7.5	0.84
CA 19–9 (U/mL)	16.8	19.4	0.16

Table 1.

Comparison of the laboratory results during chemotherapy and IP6 + Ins.

Table 2 shows comparison of the mean blood counts (erythrocytes, leukocytes, platelets) at the beginning of chemotherapy, during, and at the end of chemotherapy, evaluated by the Friedman’s test. It is known that chemotherapy can damage bone marrow and produce low counts of erythrocytes, leukocytes, and platelets, causing anemia, septicemia, and bleeding. Therefore, if the blood cell levels are too low, the next treatment might be put off until these levels recover: this is known as “chemo break”. Although there were changes in blood counts during chemotherapy, these levels were never so low that threatened patients’ lives, and chemotherapy was never interrupted (no need for “chemo break”).

Erythrocytes (E) (× 10^12/L)				Leukocytes (L) (× 10^9/L)				Platelets (P) (× 10^9/L)
E0	E1	E2	p-value	L0	L1	L2	p-value	P0	P1	P3	p-value
4.3	4.0	3.9	0.0007	7.3	5.5	4.7	0.000	281	240	230	0.00008

Table 2.

Changes in blood count values in patients on chemotherapy and IP6 + Ins.

0 = beginning of chemotherapy; 1 = middle of chemotherapy; 2 = end of chemotherapy.

Thrombocytopenia and neutropenia are usual side effects of chemotherapy. However, Figures 1 and 2 demonstrate that in two patients (Cases 1 and 2), as representatives of the group, during chemotherapy white blood cell counts (leukocytes) and platelet counts did not drop when IP6 + Ins were given to the patients, as also shown in Table 2.

Figure 1.

Leucocytes and platelet counts shown during chemotherapy (Case 1).

Figure 2.

Leucocytes and platelet counts shown during chemotherapy (Case 2).

Metastases in colorectal cancer are most commonly found in the liver and lungs. Figure 3 shows CT scan of lung metastases in a Duke’s D colon cancer patient in 2 years, indicating very slow progression of the existing and the absence of any new metastatic lesions.

Figure 3.

Lung metastases in a Duke’s D colon cancer patient, showing CT scan in 2001 (left) and in 2003 (right).

In the observed period, 3 patients died. All other patients received full dose of chemotherapy and radiotherapy, without breaks (“chemo break”).

3.3 Discussion

Because preclinical and encouraging clinical data suggest that IP6 and Ins are promising in prevention of cancer and as adjuvant therapy, more controlled clinical trials are needed and encouraged. Particularly, because the rising incidence and mortality for some cancers are of concern, and CRC is on the rise in USA among young people, despite the decrease in overall cancer frequency and death rate, that overall are encouraging. Currently, CRC is the fourth most common cancer in the United States. It was predicted that in 2023, approximately 153,020 individuals will be diagnosed with CRC and 52,550 will die from the disease [4]. However, among these, about 20,000 cases and 3750 deaths are expected in individuals younger than 50 years, which is concerning and alarming [4].

During chemotherapy, in most patients, some anomalies in their complete blood count, primarily in the number of leukocytes and platelets are happening. Studies also have associated chemotherapy with the increased risk of gastrointestinal, hematologic, and cardiac toxicities in patients with colon cancer, with the most common hematological adverse effect being agranulocytosis [43]. However, when IP6 + Ins was given in combination with chemotherapy, side effects of chemotherapy were reduced and patients were able to perform their daily activities [44, 45]. In a case study of lung cancer, the long-term survival of a patient with advanced non-small cell lung cancer treated with IP₆ + Ins treatment combined with chemo-radiotherapy was reported [46]. In a phase I clinical study with Ins, it was shown that Ins was safe and well tolerated [47]. When IP6 was combined with beta-(1,3)/(1,6) D-glucan, the favorable and beneficial effect on hematopoiesis in the treatment of patients with advanced malignancies receiving chemotherapy was demonstrated [48]. The combination of IP6 and Ins diminished the negative side effects of chemotherapy and preserved quality of life in breast cancer patients in a small prospective, randomized, pilot clinical study [44]. In a double-blind, randomized controlled trial (RCT) in women with ductal breast cancer, topical IP6 treatment was effective and safe in preventing and/or mitigating chemotherapy-induced side effects and was able to preserve quality of life [49]. To further identify the clinical evidence of the effectiveness of IP6 and Ins on the quality of life in cancer patients, and to demonstrate that IP6 and Ins were able to improve the quality of life in patients undergoing chemotherapy due to breast cancer, a literature search was conducted to identify clinical evidence of the effectiveness of IP6 and Ins on the quality of life in cancer patient and indeed demonstrated that IP6 and Ins were effective in improving quality of life of patients receiving chemotherapy due to breast cancer [50]. In a cohort of breast cancer patients, a combined oral-local treatment with IP6 and Ins was conducted, with oral myo-inositol + IP6 local application. This combined treatment with IP6 and Ins was also able to improve local symptoms and quality-of-life-related symptoms [51].

A remarkable case report on melanoma was presented by Khurana et al. [52]. The patient was with metastatic melanoma and declined traditional therapy. Instead, he decided to try the IP6 + Ins supplement only. To their surprise, the patient achieved a complete remission and remains in remission 3 years later. This might indicate a new pathway for IP6 in clinical practice - immunotherapy, a potential for immune-stimulating effects of IP6 and Ins in patients with metastatic melanoma could be explored.

In this pilot clinical observational study, a group of patients with multiple liver and lung metastases, IP6 + Ins was given as an adjuvant to chemotherapy according to Mayo protocol. Our results showed that no patient had to discontinue chemotherapy due to abnormality of hematological and/or biochemical parameters. Three patients died during the observed period. The first patient died 11 months after operation due to myocardial infarction, other two patients died 30 and 33 months after the surgery, respectively, due to dissemination of colorectal cancer. All deceased patients had colorectal cancer classified as Dukes D.

This study indicated that IP6 and Ins contributed to the anticancer effect of chemotherapy and improved the quality of life. This was a non-randomized clinical trial, which did not allow us to compare the outcome with patients without IP6 and Ins treatment. Side-effects were monitored by clinical observation, while standardized questionnaires were not used. However, based on this initial clinical observational study, a first prospective, randomized, pilot clinical study with IP6 + Ins was organized and conducted [44].

4. Conclusion

Available as dietary supplements, both with a GRAS status, IP6 and Ins have been in clinical practice for over 20 years. From many case reports, some anecdotal evidence, and few small clinical studies, the enhanced antitumor activity with improved quality of life by IP6, Ins, and their combination with reduced tumor growth rate and in some cases, even a regression of primary lesions, was reported.

Judged by multiple experimental and clinical data, it has been shown that IP6 + Ins can be a new option for cancer prevention, but also for cancer treatment, and always with ability to reduce the chemotherapy-induced side-effects. However, still more experimental data and a more controlled clinical study are needed to evaluate the antitumoral effect of IP6 + Inositol in cancer prevention and treatment and to better understand the mode of its action.

Conflicts of interest

All authors declare that there is no conflict of interest regarding the publication of this manuscript and that we have no financial interests in any commercial sources of inositol, IP6, or other inositol phosphates.