Open access peer-reviewed chapter

Infection by Salmonella enterica Promotes or Demotes Tumor Development

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Marco A. Hernández-Luna, Paola Muñóz-López, Carlos A. Aguilar- González and Rosendo Luria-Pérez

Submitted: 01 November 2017 Reviewed: 15 February 2018 Published: 18 July 2018

DOI: 10.5772/intechopen.75481

From the Edited Volume

Salmonella - A Re-emerging Pathogen

Edited by Maria Teresa Mascellino

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Abstract

Cancer is a disease that claims the lives of millions of people every year around the world. To date, multiple risk factors that may contribute to its development have been described. In recent years, a factor that has been associated to cancer development is the presence of bacterial infections that could contribute to its occurrence not only by favoring the inflammatory process, but also through the release of proteins that trigger tumorigenesis. One of the bacterial species that have recently generated interest due to its possible role in cancer development is Salmonella enterica. Nevertheless, for more than a decade, attenuated strains of Salmonella enterica have been proposed as a treatment for different neoplasms due to its bacterium tropism for the tumor microenvironment, its oncolytic activity and its ability to activate the innate and adaptive immune responses of the host. These two facets of Salmonella enterica are addressed in detail in this chapter, allowing us to understand its possible role in cancer development and its well-documented antitumor activity.

Keywords

  • Salmonella
  • cancer
  • live-attenuated bacterial vector
  • tumor selectivity
  • immunotherapy

1. Introduction

In recent years, cancer has become a worldwide public health problem, and millions of people die of this disease every year in the world [1]. Despite the efforts made to understand the mechanisms involved in carcinogenesis to better develop new therapeutic strategies, the cure for cancer remains unsolved. Among the causes that have been associated with cancer origin and development, it is found physical and chemical agents as well as biological processes such as inflammation [2], this inflammation has been associated with the presence of infectious biologic agents; these may be viral like human papilloma virus associated to cervical cancer [3], or bacterial like Helicobacter pylori in the development of gastric cancer [4], or Escherichia coli (E. coli) in the development of colon cancer [5]. In this context, Salmonella enterica has also been associated with the development of neoplasms that affecting the gastrointestinal tract such as gallbladder cancer [6] and colon cancer [7]. On the other hand, since more than a decade, attenuated strains of Salmonella enterica have been evaluated as adjuvants in the treatment of different neoplasms [8], including colon cancer [9] due to its great affinity for tumor tissue [10, 11], its oncolytic activity and the induction of the innate and adaptive immune response against the tumor [12].

The role of Salmonella enterica in cancer is a provocative issue to debate, for that reason, in this chapter, we document these two facets of Salmonella enterica as a promoter of the development of gastrointestinal tract neoplasms and as a bacterium with antitumor activity and with potential use in cancer treatment.

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2. Infection by Salmonella enterica and colon cancer

Salmonella enterica genus comprises a wide range of bacteria, including species such as Salmonella typhi and Salmonella paratyphi, for which natural host is human and Salmonella typhimurium, which has mouse as its natural host [13]. The fact that S. typhimurium causes the same type of infection in the mouse than in the human has allowed us to understand in great detail the pathogenicity and immunogenicity of these bacteria [14]. Nevertheless, the infection by Salmonella enterica has recently begun to be associated with the development of neoplasia of the gastrointestinal tract such as colon cancer [7] and gallbladder cancer [6].

The role of Salmonella enterica infection in cancer development is currently under investigation. Salmonella enterica capacity to modulate host’s inflammatory response [15], contributing to neoplasm development has been documented, showing that chronic inflammation induced by bacterial infection causes DNA damage and increases cell proliferation and migration, factors associated with cancer development [16]. Likewise, it has been suggested that at least two proteins of Salmonella enterica could trigger the development of colon cancer; the first one, the typhoid toxin, a cyclomoduline similar to E. coli CDT protein [17]; which increases cell survival and is capable of favoring dysbiosis [18], a process known as a risk factor for developing inflammatory bowel disease and colon cancer [19]; the second protein of Salmonella enterica is the effector protein AvrA, secreted via the type 3 secretion system [20], and that has been detected in stool samples obtained from patients with colon cancer [21].

AvrA is a multifunctional protein. On the one hand, AvrA is responsible for decreasing the inflammatory response by inhibiting signaling pathways such as the one induced by NF-κB [22] or suppressing the secretion of cytokines such as IL-12, IFN-γ and TNF-α [23] as well as inhibiting IL-6 transcription and increasing IL-20 transcription [24]. On the other hand, AvrA would favor tumor formation in the intestinal epithelium by activating cell proliferation pathways such as Wnt/β catenin pathway [25], associated with colon cancer [26], through two post-translational modifications, β catenin phosphorylation (activation) and deubiquitination of it (decreasing degradation) [7]. Also, AvrA activates Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway [27], which also plays an important role in carcinogenesis because it is involved in apoptosis regulation, cell proliferation and differentiation as well as on the inflammatory response [28]. In addition, AvrA has acetyl transferase activity and one of its targets is p53 [29]; when it is acetylated, it causes cell cycle arrest and apoptosis inhibition by decreasing proapoptotic proteins such as Bax [30]. AvrA mechanisms are summarized in Figure 1.

Figure 1.

Oncogenic activity of the Salmonella enterica. Once AvrA is released and internalized via the type 3 secretion system of Salmonella enterica, it exerts its oncogenic effect by modulating the following signaling pathways (1) phosphorylation and deubiquitination of β catenin, promoting cellular proliferation [7, 25], (2) STAT3 phosphorylation, fostering cell proliferation and differentiation as well as decreasing apoptosis [27] and (3) acetylation of the p53 transcription factor that decreases apoptosis by transcriptional downregulation of proapoptotic proteins such as Bax [29].

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3. Infection by Salmonella enterica and gallbladder cancer

Gallbladder cancer is the main type of neoplasm that affects the bile ducts. Even though the incidences of this neoplasm is low worldwide compared to other types of cancer that affect the gastrointestinal tract, the high incidence in some geographic regions like South America [31, 32] and Southeast Asia [33, 34] have generated a particular interest on studying the causes that contribute to the development of this type of neoplasm on these population.

The main risk factor for developing gallbladder cancer is cholelithiasis, gallstone formation (GSD), which favors the inflammatory process and damage to the epithelium [35]. Likewise, a second risk factor that has begun to be associated with the development of this neoplasia is the infection with Salmonella enterica [33], which enters the gallbladder directly from the bloodstream or through the bile [36]. Interestingly, a high incidence of Salmonella enterica has been reported in geographic regions where there is a higher number of gallbladder cancer cases [6], and several studies have shown its presence in biopsies of patients with gallbladder cancer [32, 37, 38, 39], where different serotypes of Salmonella enterica such as S. typhi, S. paratyphi, S. typhimurium and S. choleraesuis have been found [37].

To date, there is a little information about how an infection with Salmonella enterica would participate in the development of gallbladder cancer. One of the main proposed mechanisms is the induction of chronic inflammation in the gallbladder [40], which is recurring in patients with cholelithiasis [39]. Since Salmonella enterica can go unnoticed for years, and it has the ability to form biofilm on gallstones constituted by cholesterol [38]; the inflammation would increase immune cell recruitment, including activated macrophages expressing COX-2 [41], which is an enzyme that plays a role in the development of tumors in the gastrointestinal tract [42, 43]. In addition, the inflammatory process causes alterations in the TP53 gene, increasing the risk to develop gallbladder cancer [44]. Lastly, in another study, it was shown that infection with S. typhimurium in cell lines and gallbladder organoids produces malignant transformations, by activating the MAPK and AKT pathways, which were associated with the development of gallbladder tumors in a murine model [6].

According to the data presented earlier, infection with Salmonella enterica could be a factor associated with the development of neoplasms in the gastrointestinal tract, where the chronic inflammatory process induced by the bacteria, as well as some of its effector proteins would be responsible for triggering the tumor process. However, more studies are needed in order to better understand the role of Salmonella enterica in carcinogenesis.

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4. Antitumor activity of Salmonella enterica

Contrary to carcinogenesis induction, infection by bacteria such as Salmonella enterica facilitates the elimination of tumor cells [11]. The use of bacteria and their derivatives to treat cancer was first documented by William Coley over a century ago, using “Coley’s Toxin,” a compound of Streptococcus pyogenes and Serratia marcescens extract intended for the treatment of patients with sarcoma, carcinoma, lymphoma, melanoma and myeloma [45]. Since 1976, subsequent studies led to the use of the attenuated strain of Mycobacterium bovis (Bacillus de Calmette-Guérin, BCG) administered intravesically as immunotherapy against superficial transitional cell bladder carcinoma [46].

To date, Salmonella enterica is one of the most studied bacteria in the fight against cancer [11]. Results of a phase I clinical trial with S. typhimurium strain VNP20009 showed that the bacterium does not lead to severe adverse effects and it is well tolerated by patients with metastatic melanoma, metastatic renal carcinoma, carcinoma of the head and neck and esophageal adenocarcinoma [47, 48, 49]. The mechanisms implicated in the ability of Salmonella enterica to eliminate tumors remain under scrutiny, but its tropism for the tumor microenvironment, its oncolytic activity and its ability to activate the innate and adaptive immune responses of the host have been documented (Figure 2).

Figure 2.

Salmonella enterica selectivity for the tumor, oncolytic activity and induction of immune response. Once Salmonella enterica reaches the tumor tissue, attracted by molecules such as aspartate, serine, ribose/galactose [50, 51] and ethanolamine [53], it induces its antitumor oncolytic activity promoting cell death via nitric oxide production [74], decreased angiogenesis [78], autophagy activation [79, 80], activation of immunogenic death [81] and activation of the innate and adaptive antitumor immune responses [74, 87, 89, 90, 91].

4.1. Tumor selectivity of Salmonella enterica

For over a decade, the use of live-attenuated strains of Salmonella enterica as a therapeutic alternative against cancer [8, 11] has been favored by this bacterium’s ability to effectively and selectively colonize the tumor microenvironment [8, 12]. Several studies have described how Salmonella enterica infects and replicates within tumors in murine models in a 1:1000 ratio compared to normal tissue [10]. Although the mechanisms of tumor selectivity are still controversial, in vitro studies mimicking the tumor microenvironment have shown that Salmonella enterica migrates to the tumor tissue due to attraction by certain molecules such as amino acids and carbohydrates that allow the bacteria to arrive and penetrate the tumor tissue and then direct to the necrotic area [50, 51]. In addition, ethanolamine, a molecule found in elevated concentrations in different types of neoplasia [52], has also been found to act as a chemotactic agent because the deletion of the eutC gene (part of the operon encoding the enzyme ethanolamine-ammonia-lyase (EAL) which metabolizes ethanolamine [53]) in Salmonella enterica, decreased its colonization in a murine model of breast cancer [54].

Other studies have referred that Salmonella enterica migration involves motility proteins such as the CheA/CheY system [50, 51, 55], proteins fliA, fliC and flgE [56] and the motAB gene, the flagellar motor of the bacteria [54]. The Salmonella enterica metabolic pathways of aromatic amino acids (aroA) and purines (purA) are also relevant since mutations in these metabolic pathways lead to decreased recruitment in tumor tissue [56, 57].

On the other hand, the microenvironment in the tumor characterized by (1) hypoxia [58], (2) acidity [59] and (3) necrosis contributes to bacterial proliferation [11]. The permanence of Salmonella enterica in tumor tissue may be fostered by low macrophage and neutrophil activity [60], suppression of the immune response mediated by cytokines such as TGF-β, and the difficult access of anti-Salmonella antibodies and factors of the complement pathway due to the irregular growth of blood vessels in the tumor [61].

4.2. Oncolytic activity of Salmonella enterica

Several studies have documented the antitumor activity of Salmonella enterica in murine cancer models, including lung cancer [62], carcinoma of the colon [57, 63], prostate cancer [64], T-cell metastatic lymphoma [65] and B-cell lymphoma [66], among others. In these studies, Salmonella enterica inhibited tumor growth and its metastases, while also increasing the lifespan of the mice. These results are consistent with reports in murine models of xenotransplants of breast cancer [67] and prostate cancer [68, 69], using auxotrophic strains of S. typhimurium such as the A1 strain (deficient in leucine and arginine synthesis) and the A1-R strain (deficient in leucine and arginine synthesis but with a greater capacity to eliminate tumor cells); these do not cause any injuries in the host because the bacterium has greater affinity for the tumor tissue [67]. Other studies have shown that the A1-R strain inhibits the formation of metastases in bone of murine breast cancer models [70] as well as metastases from osteosarcoma [71], pancreatic cancer [72] and dorsal spinal cord gliomas [73].

Although the mechanisms through which Salmonella enterica induces tumor cell death are still under study, some proposed mechanisms involve: (1) apoptosis induction via nitric oxide (NO) production [74]: NO, the product of nitrate and nitrite degradation (generated by the hypoxic tumor microenvironment) [75] via Salmonella enterica nitrate reductase (NirB) [76], could induce the intrinsic apoptotic pathway [77]. (2) Decreased angiogenesis: Salmonella enterica inhibits the expression of the transcription factor HIF-1α and thus, the decrease in vascular endothelial growth factor (VEGF) [78]. (3) Autophagy activation through the AKT/mTOR pathway: the presence of Salmonella enterica in the tumor decreases phosphorylation of the proteins AKT and mTOR and increases the expression of Beclin-1 and LC3 (microtubule-associated protein 1A/1B-light chain 3) [79, 80], thus promoting autophagy. (4) Induction of immunogenic cell death (ICD): this type of cell death could be caused by calreticulin (CRT) [81], a protein in the endoplasmic reticulum, when secreted by the cell participating in ICD [82], which increases due to the presence of Salmonella enterica in tumor tissue. Other mechanisms involved in tumor cell elimination and fostered by Salmonella enterica include the induction of the innate and adaptive immune response, as described later.

4.3. Activation of the innate antitumor response by Salmonella enterica

The immune response generated against Salmonella enterica once it has entered the host [83, 84] plays an important role in tumor recognition due to the recruitment of immune response cells in the tumor and its metastases [85, 86]. In the tumor microenvironment, Salmonella enterica induces the reversal of the suppressor environment by facilitating the expression of soluble mediators such as inducible nitric oxide synthase (iNOS) and interferon-γ (IFN-γ), molecules that promote antitumor activity and inhibit the expression of immunosuppressive factors such as arginase-1, interleukin-4 (IL-4), transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) [8, 87]; also, Salmonella enterica decreases the activity of myeloid-derived suppressor cells (MDSCs) [88] and promotes the recruitment of natural killer (NK) cells [89], neutrophils [74], macrophages [87] and T [90] and B lymphocytes [91]. The first studies describing the immunotherapeutic antitumor properties of Salmonella enterica were reported by Kurashige S. et al.; whereby with the use of mini cells (vesicles with no genomic DNA) obtained from S. typhimurium and administered to a murine sarcoma model [92] and T-cell lymphoma [93], and macrophage activity was restored in the tumor microenvironment and helped eliminate the tumor.

Some studies have documented the ability of Salmonella enterica to induce the activation of the inflammasome during the early stages of bacterial colonization, via type NOD receptors (NLR) [94], favoring interleukin-1β (IL-1β) and TNF-α activation [95], and increasing the levels of proinflammatory cytokines and decreasing those of anti-inflammatory cytokines [86] in the tumor microenvironment. The antitumor efficacy of Salmonella enterica is further promoted by the induction of the immune response via TLR-MYD88 signaling, thus establishing that cytokine production and modulation may result from the activation of toll-like receptors (TLRs) in the tumor tissue [96].

It is known that bacterial components of Salmonella enterica, such as lipopolysaccharide (LPS), flagellin and the CpG sites are recognized by the TLRs, and lead to activation of the signaling pathways inducing the innate and adaptive immune responses. In this context, the interaction of the LPS from Salmonella enterica with TLR4 has been shown to contribute to decreased tumor growth and to the recruitment of neutrophils and macrophages [97]. Likewise, the interaction of Salmonella enterica flagellin with TLR5 prevented the development of metastases in a murine melanoma model [98]. These results were consistent with the use of a TLR5 agonist used in a murine lymphoma model in which the antitumor effect was associated to the activation of CD8+ lymphocytes and NK cells [99]. Subsequent studies using TLR4 and TLR5 knockout (KO) mice have confirmed their role in the antitumor response mediated by Salmonella enterica [100].

The antitumor effects, to which TLRs have been associated, are the recruitment of cells such as macrophages, NK cells, T and B lymphocytes, resulting from increased TNF-α level due to TLR4 activation by LPS [95, 101]. The increased TNF-α would therefore promote bleeding from the blood vessels of the tumor and allow the infiltration by immune response cells [102] that would eliminate the tumor cells. Further, the presence of Salmonella enterica in tumor tissue increases the amount of immune response cells in the spleen [81], which subsequently migrate to the tumor and contribute to its eradication.

4.4. Induction of the antitumor adaptive immune response by Salmonella enterica

Some studies have described that the adaptive immune response induced against Salmonella enterica antigens is one of the mechanisms eliminating tumor cells. Tumor cells infected with Salmonella enterica and that present these antigens of the bacteria are eliminated by cytotoxic T lymphocytes; this has been documented in the elimination of solid and non-solid tumors [85, 89].

Salmonella enterica contributes to the reversal of tumor immune tolerance by decreasing the number of Treg lymphocytes (CD4+ CD25+) in tumor tissue [103] due to the effects of LPS and the Braun lipoprotein (Lpp) of Salmonella enterica [104], and the decreased levels of indoleamine 2, 3 dioxygenase 1 (IDO1) (enzyme participating in tryptophan metabolism and associated with the development of immune tolerance by T lymphocytes) [105, 106], precluding the formation of kynurenine and thus favoring the proliferation of T lymphocytes capable of recognizing and eliminating the tumor [79]. Aside from reversing immune tolerance and promoting the recruitment of immune response cells in the tumor microenvironment, Salmonella enterica also induces the activation and maturation of T lymphocytes [107], probably as a result of the induced overexpression of gap junction proteins such as connexin 43 (Cx43) [108]; this protein plays a role in B and T lymphocyte activation [109] as well as in antigen presentation to DC [110], thus allowing the transfer of tumor cell preprocessed antigens to DC for their adequate presentation by MHC class I [108], thus generating a specific antitumor response.

Studies conducted by Shilling et al. [111] showed that the in vitro activation of DC purified from mice, with cytoplasmic fractions of S. typhimurium and with heat shock proteins from tumor cells, prevented tumor formation after regrafting. Further, they showed that activated dendritic cells tended to preferentially localize in the tumor. These studies were consistent with the reports published by Avogadri F et al., which observed that the intravenous administration of Salmonella enterica favored cross-presentation of tumor antigens to DC, inducing the activation of CD8+ lymphocytes capable of recognizing the tumor [86]. Studies conducted by Grille et al. demonstrated that the administration of Salmonella enterica to a murine B-cell lymphoma model induced a local and systemic antitumor response, with the recruitment of CD8+ and CD4+ lymphocytes in the tumor and the presence of specific antibodies directed against the tumor cells [89].

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5. Conclusion

The aforementioned data document the duality of the infection caused by Salmonella enterica, in which the chronic inflammation promoted by this bacterium induces DNA injury, and some proteins of the bacterium increase cellular proliferation and migration and decrease the cell death, all these factors are associated with the development of cancer. On the other hand, infection with attenuated strains of Salmonella enterica promotes the elimination of tumor cells via intrinsic mechanisms that induce an oncolytic effect on the tumor cell while simultaneously promoting antitumor innate and adaptive immune responses; it appears to be an excellent candidate as a therapeutic alternative against cancer [8].

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Acknowledgments

R.L.P. acknowledges the support from CONACYT (CB-2013-01-222446, INFR-2015-01-255341, PN-2015-01-1537), and Fondos Federales (HIM-2016-114 SSA 1333).

M.A.H.L. acknowledges the support from PRODEP (UGTO-PTC-537) and SICES (IJS/CON/102/2017UG).

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Conflict of interest

The authors have no conflict of interest to declare.

References

  1. 1. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA: A Cancer Journal for Clinicians. 2011;61(2):69-90
  2. 2. Elinav E, Nowarski R, Thaiss CA, Hu B, Jin C, Flavell RA. Inflammation-induced cancer: Crosstalk between tumours, immune cells and microorganisms. Nature Reviews. Cancer. 2013;13(11):759-771
  3. 3. Mangino G, Chiantore MV, Iuliano M, Fiorucci G, Romeo G. Inflammatory microenvironment and human papillomavirus-induced carcinogenesis. Cytokine & Growth Factor Reviews. 2016;30:103-111
  4. 4. Polk DB, Peek RM, Jr.: Helicobacter pylori: Gastric cancer and beyond. Nature Reviews. Cancer 2010, 10(6):403-414
  5. 5. Hernández-Luna MA, Lagunes-Servin HE, Lopez-Briones S. The role of Escherichia coli in the development and progression of cancer. ARC Journal of Cancer Science. 2016;3(1):1-11
  6. 6. Scanu T, Spaapen RM, Bakker JM, Pratap CB, Wu LE, Hofland I, Broeks A, Shukla VK, Kumar M, Janssen H, et al. Salmonella manipulation of host signaling pathways provokes cellular transformation associated with gallbladder carcinoma. Cell Host & Microbe. 2015;17(6):763-774
  7. 7. Lu R, Wu S, Zhang YG, Xia Y, Liu X, Zheng Y, Chen H, Schaefer KL, Zhou Z, Bissonnette M, et al. Enteric bacterial protein AvrA promotes colonic tumorigenesis and activates colonic beta-catenin signaling pathway. Oncogene. 2014;3:e105
  8. 8. Chavez-Navarro H, Hernández-Cueto DD, Vilchis-Estrada A, Bermúdez-Pulido DC, Antonio-Andrés G, Luria-Pérez R. Salmonella enterica: An ally in the therapy of cancer. Boletín Médico del Hospital Infantil de México. 2015;72(1):15-25
  9. 9. Liu X, Jiang S, Piao L, Yuan F. Radiotherapy combined with an engineered Salmonella typhimurium inhibits tumor growth in a mouse model of colon cancer. Experimental Animals. 2016;65(4):413-418
  10. 10. Pawelek JM, Low KB, Bermudes D. Tumor-targeted salmonella as a novel anticancer vector. Cancer Research. 1997;57(20):4537-4544
  11. 11. Forbes NS. Engineering the perfect (bacterial) cancer therapy. Nature Reviews. Cancer. 2010;10(11):785-794
  12. 12. Hernandez-Luna MA, Luria-Perez R, Huerta-Yepez S. Therapeutic intervention alternatives in cancer, using attenuated live bacterial vectors: Salmonella enterica as a carrier of heterologous molecules. Revista de Investigación Clínica. 2013;65(1):65-73
  13. 13. Spano S. Mechanisms of Salmonella Typhi host restriction. Advances in Experimental Medicine and Biology. 2016;915:283-294
  14. 14. Kurtz JR, Goggins JA, McLachlan JB. Salmonella infection: Interplay between the bacteria and host immune system. Immunology Letters. 2017;190:42-50
  15. 15. LaRock DL, Chaudhary A, Miller SI. Salmonellae interactions with host processes. Nature Reviews. Microbiology. 2015;13(4):191-205
  16. 16. Kuper H, Adami HO, Trichopoulos D. Infections as a major preventable cause of human cancer. Journal of Internal Medicine. 2000;248(3):171-183
  17. 17. Grasso F, Frisan T. Bacterial Genotoxins: Merging the DNA damage response into infection biology. Biomolecules. 2015;5(3):1762-1782
  18. 18. Del Bel Belluz L, Guidi R, Pateras IS, Levi L, Mihaljevic B, Rouf SF, Wrande M, Candela M, Turroni S, Nastasi C, et al. The typhoid toxin promotes host survival and the establishment of a persistent asymptomatic infection. PLoS Pathogens. 2016;12(4):e1005528
  19. 19. Kang M, Martin A. Microbiome and colorectal cancer: Unraveling host-microbiota interactions in colitis-associated colorectal cancer development. Seminars in Immunology. 2017;32:3-13
  20. 20. Ye Z, Petrof EO, Boone D, Claud EC, Sun J. Salmonella effector AvrA regulation of colonic epithelial cell inflammation by deubiquitination. The American Journal of Pathology. 2007;171(3):882-892
  21. 21. Lu R, Bosland M, Xia Y, Zhang YG, Kato I, Sun J. Presence of Salmonella AvrA in colorectal tumor and its precursor lesions in mouse intestine and human specimens. Oncotarget. 2017;8(33):55104-55115
  22. 22. Liu X, Lu R, Xia Y, Wu S, Sun J. Eukaryotic signaling pathways targeted by Salmonella effector protein AvrA in intestinal infection in vivo. BMC Microbiology. 2010;10:326
  23. 23. Lu R, Wu S, Liu X, Xia Y, Zhang YG, Sun J. Chronic effects of a Salmonella type III secretion effector protein AvrA in vivo. PLoS One. 2010;5(5):e10505
  24. 24. Lu R, Liu X, Wu S, Xia Y, Zhang YG, Petrof EO, Claud EC, Sun J. Consistent activation of the beta-catenin pathway by Salmonella type-three secretion effector protein AvrA in chronically infected intestine. American Journal of Physiology. Gastrointestinal and Liver Physiology. 2012;303(10):G1113-G1125
  25. 25. Liu X, Lu R, Wu S, Sun J. Salmonella regulation of intestinal stem cells through the Wnt/beta-catenin pathway. FEBS Letters. 2010;584(5):911-916
  26. 26. Wang Z, Vogelstein B, Kinzler KW. Phosphorylation of beta-catenin at S33, S37, or T41 can occur in the absence of phosphorylation at T45 in colon cancer cells. Cancer Research. 2003;63(17):5234-5235
  27. 27. Lu R, Wu S, Zhang YG, Xia Y, Zhou Z, Kato I, Dong H, Bissonnette M, Sun J. Salmonella protein AvrA activates the STAT3 signaling pathway in colon cancer. Neoplasia. 2016;18(5):307-316
  28. 28. Lu R, Zhang YG, Sun J. STAT3 activation in infection and infection-associated cancer. Molecular and Cellular Endocrinology. 2017;451:80-87
  29. 29. Wu S, Ye Z, Liu X, Zhao Y, Xia Y, Steiner A, Petrof EO, Claud EC, Sun J. Salmonella typhimurium infection increases p53 acetylation in intestinal epithelial cells. American Journal of Physiology. Gastrointestinal and Liver Physiology. 2010;298(5):G784-G794
  30. 30. Yamaguchi H, Woods NT, Piluso LG, Lee HH, Chen J, Bhalla KN, Monteiro A, Liu X, Hung MC, Wang HG. p53 acetylation is crucial for its transcription-independent proapoptotic functions. The Journal of Biological Chemistry. 2009;284(17):11171-11183
  31. 31. Lazcano-Ponce EC, Miquel JF, Munoz N, Herrero R, Ferrecio C, Wistuba II, Alonso de Ruiz P, Aristi Urista G, Nervi F. Epidemiology and molecular pathology of gallbladder cancer. CA: A Cancer Journal for Clinicians. 2001;51(6):349-364
  32. 32. Koshiol J, Wozniak A, Cook P, Adaniel C, Acevedo J, Azocar L, Hsing AW, Roa JC, Pasetti MF, Miquel JF, et al. Salmonella enterica serovar Typhi and gallbladder cancer: A case-control study and meta-analysis. Cancer Medicine. 2016;5(11):3310-3235
  33. 33. Nagaraja V, Eslick GD. Systematic review with meta-analysis: The relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Alimentary Pharmacology & Therapeutics. 2014;39(8):745-750
  34. 34. Randi G, Franceschi S, La Vecchia C. Gallbladder cancer worldwide: Geographical distribution and risk factors. International Journal of Cancer. 2006;118(7):1591-1602
  35. 35. Pilgrim CH, Groeschl RT, Christians KK, Gamblin TC. Modern perspectives on factors predisposing to the development of gallbladder cancer. HPB: The Official Journal of the International Hepato Pancreato Biliary Association. 2013;15(11):839-844
  36. 36. Parry CM, Hien TT, Dougan G, White NJ, Farrar JJ. Typhoid fever. The New England Journal of Medicine. 2002;347(22):1770-1782
  37. 37. Iyer P, Barreto SG, Sahoo B, Chandrani P, Ramadwar MR, Shrikhande SV, Dutt A. Non-typhoidal Salmonella DNA traces in gallbladder cancer. Infectious Agents and Cancer. 2016;11:12
  38. 38. Dongol S, Thompson CN, Clare S, Nga TV, Duy PT, Karkey A, Arjyal A, Koirala S, Khatri NS, Maskey P, et al. The microbiological and clinical characteristics of invasive Salmonella in gallbladders from cholecystectomy patients in Kathmandu, Nepal. PLoS One. 2012;7(10):e47342
  39. 39. Walawalkar YD, Gaind R, Nayak V. Study on Salmonella Typhi occurrence in gallbladder of patients suffering from chronic cholelithiasis-a predisposing factor for carcinoma of gallbladder. Diagnostic Microbiology and Infectious Disease. 2013;77(1):69-73
  40. 40. Menendez A, Arena ET, Guttman JA, Thorson L, Vallance BA, Vogl W, Finlay BB. Salmonella infection of gallbladder epithelial cells drives local inflammation and injury in a model of acute typhoid fever. The Journal of Infectious Diseases. 2009;200(11):1703-1713
  41. 41. Carotti S, Guarino MP, Cicala M, Perrone G, Alloni R, Segreto F, Rabitti C, Morini S. Effect of ursodeoxycholic acid on inflammatory infiltrate in gallbladder muscle of cholesterol gallstone patients. Neurogastroenterology and Motility. 2010;22(8):866-873, e232
  42. 42. Ye Y, Liu M, Yuan H, Ning S, Wang Y, Chen Z, Ji R, Guo Q, Li Q, Zhou Y. COX-2 regulates snail expression in gastric cancer via the Notch1 signaling pathway. International Journal of Molecular Medicine. 2017;40(2):512-522
  43. 43. Sorski L, Melamed R, Matzner P, Lavon H, Shaashua L, Rosenne E, Ben-Eliyahu S. Reducing liver metastases of colon cancer in the context of extensive and minor surgeries through beta-adrenoceptors blockade and COX2 inhibition. Brain, Behavior, and Immunity. 2016;58:91-98
  44. 44. Espinoza JA, Bizama C, Garcia P, Ferreccio C, Javle M, Miquel JF, Koshiol J, Roa JC. The inflammatory inception of gallbladder cancer. Biochimica et Biophysica Acta. 2016;1865(2):245-254
  45. 45. Coley WB. The treatment of inoperable sarcoma by bacterial toxins (the mixed toxins of the streptococcus erysipelas and the Bacillus prodigiosus). Proceedings of the Royal Society of Medicine. 1910;3(Surg Sect):1-48
  46. 46. Kamat AM, Lamm DL. Immunotherapy for bladder cancer. Current Urology Reports. 2001;2(1):62-69
  47. 47. Toso JF, Gill VJ, Hwu P, Marincola FM, Restifo NP, Schwartzentruber DJ, Sherry RM, Topalian SL, Yang JC, Stock F, et al. Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma. Journal of Clinical Oncology. 2002;20(1):142-152
  48. 48. Nemunaitis J, Cunningham C, Senzer N, Kuhn J, Cramm J, Litz C, Cavagnolo R, Cahill A, Clairmont C, Sznol M. Pilot trial of genetically modified, attenuated Salmonella expressing the E. coli cytosine deaminase gene in refractory cancer patients. Cancer Gene Therapy. 2003;10(10):737-744
  49. 49. Heimann DM, Rosenberg SA. Continuous intravenous administration of live genetically modified Salmonella typhimurium in patients with metastatic melanoma. Journal of Immunotherapy. 2003;26(2):179-180
  50. 50. Kasinskas RW, Forbes NS. Salmonella typhimurium specifically chemotax and proliferate in heterogeneous tumor tissue in vitro. Biotechnology and Bioengineering. 2006;94(4):710-721
  51. 51. Kasinskas RW, Forbes NS. Salmonella typhimurium lacking ribose chemoreceptors localize in tumor quiescence and induce apoptosis. Cancer Research. 2007;67(7):3201-3209
  52. 52. Cheng M, Bhujwalla ZM, Glunde K. Targeting phospholipid metabolism in cancer. Frontiers in Oncology. 2016;6:266
  53. 53. Bovell AM, Warncke K. The structural model of Salmonella typhimurium ethanolamine ammonia-lyase directs a rational approach to the assembly of the functional [(EutB-EutC)(2)](3) oligomer from isolated subunits. Biochemistry. 2013;52(8):1419-1428
  54. 54. Silva-Valenzuela CA, Desai PT, Molina-Quiroz RC, Pezoa D, Zhang Y, Porwollik S, Zhao M, Hoffman RM, Contreras I, Santiviago CA, et al. Solid tumors provide niche-specific conditions that lead to preferential growth of Salmonella. Oncotarget. 2016;7(23):35169-35180
  55. 55. Mariconda S, Wang Q, Harshey RM. A mechanical role for the chemotaxis system in swarming motility. Molecular Microbiology. 2006;60(6):1590-1602
  56. 56. Stritzker J, Weibel S, Seubert C, Gotz A, Tresch A, van Rooijen N, Oelschlaeger TA, Hill PJ, Gentschev I, Szalay AA. Enterobacterial tumor colonization in mice depends on bacterial metabolism and macrophages but is independent of chemotaxis and motility. International Journal of Medical Microbiology. 2010;300(7):449-456
  57. 57. Crull K, Bumann D, Weiss S. Influence of infection route and virulence factors on colonization of solid tumors by Salmonella enterica serovar Typhimurium. FEMS Immunology and Medical Microbiology. 2011;62(1):75-83
  58. 58. Wei MQ, Ellem KA, Dunn P, West MJ, Bai CX, Vogelstein B. Facultative or obligate anaerobic bacteria have the potential for multimodality therapy of solid tumours. European Journal of Cancer. 2007;43(3):490-496
  59. 59. Martinez-Outschoorn UE, Peiris-Pages M, Pestell RG, Sotgia F, Lisanti MP. Cancer metabolism: A therapeutic perspective. Nature Reviews. Clinical Oncology. 2017;14(1):11-31
  60. 60. Westphal K, Leschner S, Jablonska J, Loessner H, Weiss S. Containment of tumor-colonizing bacteria by host neutrophils. Cancer Research. 2008;68(8):2952-2960
  61. 61. Loeffler M, Le'Negrate G, Krajewska M, Reed JC. Salmonella typhimurium engineered to produce CCL21 inhibit tumor growth. Cancer Immunology, Immunotherapy. 2009;58(5):769-775
  62. 62. Chen G, Wei DP, Jia LJ, Tang B, Shu L, Zhang K, Xu Y, Gao J, Huang XF, Jiang WH, et al. Oral delivery of tumor-targeting Salmonella exhibits promising therapeutic efficacy and low toxicity. Cancer Science. 2009;100(12):2437-2443
  63. 63. Yun M, Pan S, Jiang SN, Nguyen VH, Park SH, Jung CH, Kim HS, Min JJ, Choy HE, Hong Y. Effect of Salmonella treatment on an implanted tumor (CT26) in a mouse model. Journal of Microbiology. 2012;50(3):502-510
  64. 64. Choe E, Kazmierczak RA, Eisenstark A. Phenotypic evolution of therapeutic Salmonella enterica serovar Typhimurium after invasion of TRAMP mouse prostate tumor. MBio. 2014;5(4):e01182-01114
  65. 65. Vendrell A, Gravisaco MJ, Goin JC, Pasetti MF, Herschllik L, De Toro J, Rodriguez C, Larotonda G, Mongini C, Waldner CI. Therapeutic effects of Salmonella typhi in a mouse model of T-cell lymphoma. Journal of Immunotherapy. 2013;36(3):171-180
  66. 66. Grille S, Moreno M, Brugnini A, Lens D, Chabalgoity JA. A therapeutic vaccine using Salmonella-modified tumor cells combined with interleukin-2 induces enhanced antitumor immunity in B-cell lymphoma. Leukemia Research. 2013;37(3):341-348
  67. 67. Zhao M, Yang M, Ma H, Li X, Tan X, Li S, Yang Z, Hoffman RM. Targeted therapy with a Salmonella typhimurium leucine-arginine auxotroph cures orthotopic human breast tumors in nude mice. Cancer Research. 2006;66(15):7647-7652
  68. 68. Zhao M, Yang M, Li XM, Jiang P, Baranov E, Li S, Xu M, Penman S, Hoffman RM. Tumor-targeting bacterial therapy with amino acid auxotrophs of GFP-expressing Salmonella typhimurium. Proceedings of the National Academy of Sciences of the United States of America. 2005;102(3):755-760
  69. 69. Zhao M, Geller J, Ma H, Yang M, Penman S, Hoffman RM. Monotherapy with a tumor-targeting mutant of Salmonella typhimurium cures orthotopic metastatic mouse models of human prostate cancer. Proceedings of the National Academy of Sciences of the United States of America. 2007;104(24):10170-10174
  70. 70. Miwa S, Yano S, Zhang Y, Matsumoto Y, Uehara F, Yamamoto M, Hiroshima Y, Kimura H, Hayashi K, Yamamoto N, et al. Tumor-targeting Salmonella typhimurium A1-R prevents experimental human breast cancer bone metastasis in nude mice. Oncotarget. 2014;5(16):7119-7125
  71. 71. Hayashi K, Zhao M, Yamauchi K, Yamamoto N, Tsuchiya H, Tomita K, Kishimoto H, Bouvet M, Hoffman RM. Systemic targeting of primary bone tumor and lung metastasis of high-grade osteosarcoma in nude mice with a tumor-selective strain of Salmonella typhimurium. Cell Cycle. 2009;8(6):870-875
  72. 72. Nagakura C, Hayashi K, Zhao M, Yamauchi K, Yamamoto N, Tsuchiya H, Tomita K, Bouvet M, Hoffman RM. Efficacy of a genetically-modified Salmonella typhimurium in an orthotopic human pancreatic cancer in nude mice. Anticancer Research. 2009;29(6):1873-1878
  73. 73. Kimura H, Zhang L, Zhao M, Hayashi K, Tsuchiya H, Tomita K, Bouvet M, Wessels J, Hoffman RM. Targeted therapy of spinal cord glioma with a genetically modified Salmonella typhimurium. Cell Proliferation. 2010;43(1):41-48
  74. 74. Barak Y, Schreiber F, Thorne SH, Contag CH, Debeer D, Matin A. Role of nitric oxide in Salmonella typhimurium-mediated cancer cell killing. BMC Cancer. 2010;10:146
  75. 75. Brown JM, Wilson WR. Exploiting tumour hypoxia in cancer treatment. Nature Reviews. Cancer. 2004;4(6):437-447
  76. 76. Spector MP, Garcia del Portillo F, Bearson SM, Mahmud A, Magut M, Finlay BB, Dougan G, Foster JW, Pallen MJ. The rpoS-dependent starvation-stress response locus stiA encodes a nitrate reductase (narZYWV) required for carbon-starvation-inducible thermotolerance and acid tolerance in Salmonella typhimurium. Microbiology. 1999;145(Pt 11):3035-3045
  77. 77. McLaughlin LM, Demple B. Nitric oxide-induced apoptosis in lymphoblastoid and fibroblast cells dependent on the phosphorylation and activation of p53. Cancer Research. 2005;65(14):6097-6104
  78. 78. Tu DG, Chang WW, Lin ST, Kuo CY, Tsao YT, Lee CH. Salmonella inhibits tumor angiogenesis by downregulation of vascular endothelial growth factor. Oncotarget. 2016;7(25):37513-37523
  79. 79. Kuan YD, Lee CH. Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression. Oncotarget. 2016;7(1):374-385
  80. 80. Lee CH, Lin ST, Liu JJ, Chang WW, Hsieh JL, Wang WK. Salmonella induce autophagy in melanoma by the downregulation of AKT/mTOR pathway. Gene Therapy. 2014;21(3):309-316
  81. 81. Chirullo B, Ammendola S, Leonardi L, Falcini R, Petrucci P, Pistoia C, Vendetti S, Battistoni A, Pasquali P. Attenuated mutant strain of Salmonella Typhimurium lacking the ZnuABC transporter contrasts tumor growth promoting anti-cancer immune response. Oncotarget. 2015;6(19):17648-17660
  82. 82. Eggleton P, Bremer E, Dudek E, Michalak M. Calreticulin, a therapeutic target? Expert Opinion on Therapeutic Targets. 2016;20(9):1137-1147
  83. 83. Broz P, Ohlson MB, Monack DM. Innate immune response to Salmonella typhimurium, a model enteric pathogen. Gut Microbes. 2012;3(2):62-70
  84. 84. Pham OH, McSorley SJ. Protective host immune responses to Salmonella infection. Future Microbiology. 2015;10(1):101-110
  85. 85. Avogadri F, Martinoli C, Petrovska L, Chiodoni C, Transidico P, Bronte V, Longhi R, Colombo MP, Dougan G, Rescigno M. Cancer immunotherapy based on killing of Salmonella-infected tumor cells. Cancer Research. 2005;65(9):3920-3927
  86. 86. Avogadri F, Mittal D, Saccheri F, Sarrafiore M, Ciocca M, Larghi P, Orecchia R, Rescigno M. Intra-tumoral Salmonella typhimurium induces a systemic anti-tumor immune response that is directed by low-dose radiation to treat distal disease. European Journal of Immunology. 2008;38(7):1937-1947
  87. 87. Kaimala S, Mohamed YA, Nader N, Issac J, Elkord E, Chouaib S, Fernandez-Cabezudo MJ, Al-Ramadi BK. Salmonella-mediated tumor regression involves targeting of tumor myeloid suppressor cells causing a shift to M1-like phenotype and reduction in suppressive capacity. Cancer Immunology, Immunotherapy. 2014;63(6):587-599
  88. 88. Tam JW, Kullas AL, Mena P, Bliska JB, van der Velden AW: CD11b+ Ly6Chi Ly6G- immature myeloid cells recruited in response to Salmonella enterica serovar Typhimurium infection exhibit protective and immunosuppressive properties. Infection and Immunity 2014, 82(6):2606-2614.
  89. 89. Grille S, Moreno M, Bascuas T, Marques JM, Munoz N, Lens D, Chabalgoity JA. Salmonella enterica serovar Typhimurium immunotherapy for B-cell lymphoma induces broad anti-tumour immunity with therapeutic effect. Immunology. 2014;143(3):428-437
  90. 90. Lee CH, Hsieh JL, Wu CL, Hsu PY, Shiau AL. T cell augments the antitumor activity of tumor-targeting Salmonella. Applied Microbiology and Biotechnology. 2011;90(4):1381-1388
  91. 91. Lee CH, Hsieh JL, Wu CL, Hsu HC, Shiau AL. B cells are required for tumor-targeting Salmonella in host. Applied Microbiology and Biotechnology. 2011;92(6):1251-1260
  92. 92. Kurashige S. S M: Enhancing effects of mini-cells prepared from Salmonella typhimurium on anti-tumor immunity in sarcoma 180-bearing mice. Cancer Immunology, Immunotherapy. 1982;14(1):1-3
  93. 93. Kurashige S, Akuzawa Y. S M: Synergistic anti-suppressor effect of mini cells prepared from Salmonella typhimurium and mitomycin C in EL 4-bearing mice. Cancer Immunology, Immunotherapy CII. 1985;19(2):127-129
  94. 94. Phan TX, Nguyen VH, Duong MT, Hong Y, Choy HE, Min JJ. Activation of inflammasome by attenuated Salmonella typhimurium in bacteria-mediated cancer therapy. Microbiology and Immunology. 2015;59(11):664-675
  95. 95. Kim JE, Phan TX, Nguyen VH, Dinh-Vu HV, Zheng JH, Yun M, Park SG, Hong Y, Choy HE, Szardenings M, et al. Salmonella typhimurium suppresses tumor growth via the pro-inflammatory cytokine interleukin-1beta. Theranostics. 2015;5(12):1328-1342
  96. 96. Chang W-W, Lee C-H. Salmonella as an innovative therapeutic antitumor agent. International Journal of Molecular Sciences. 2014;15(8):14546-14554
  97. 97. Lee CH, Wu CL, Shiau AL. Toll-like receptor 4 mediates an antitumor host response induced by Salmonella choleraesuis. Clinical Cancer Research. 2008;14(6):1905-1912
  98. 98. de Melo FM, Braga CJ, Pereira FV, Maricato JT, Origassa CS, Souza MF, Melo AC, Silva P, Tomaz SL, KP G. Anti-metastatic immunotherapy based on mucosal administration of flagellin and immunomodulatory P10. Immunology and Cell Biology. 2015;93(1):86-98
  99. 99. Leigh ND, Bian G, Ding X, Liu H, Aygun-Sunar S, Burdelya LG, Gudkov AV. X C: A flagellin-derived toll-like receptor 5 agonist stimulates cytotoxic lymphocyte-mediated tumor immunity. PLoS One. 2014;9(1):e85587
  100. 100. Zheng JH, Nguyen VH, Jiang SN, Park SH, Tan W, Hong SH, Shin MG, Chung IJ, Hong Y, HS B. Two-step enhanced cancer immunotherapy with engineered Salmonella typhimurium secreting heterologous flagellin. Science Translational Medicine. 2017;9(376):1-10
  101. 101. Kocijancic D, Leschner S, Felgner S, Komoll RM, Frahm M, Pawar V, Weiss S. Therapeutic benefit of Salmonella attributed to LPS and TNF-alpha is exhaustible and dictated by tumor susceptibility. Oncotarget. 2017;8(22):36492-36508
  102. 102. Leschner S, Westphal K, Dietrich N, Viegas N, Jablonska J, Lyszkiewicz M, Lienenklaus S, Falk W, Gekara N. H L: Tumor invasion of Salmonella enterica serovar Typhimurium is accompanied by strong hemorrhage promoted by TNF-alpha. PLoS One. 2009;4(8):e6692
  103. 103. Senbanjo LT, Chellaiah MA. CD44: A multifunctional cell surface adhesion receptor is a regulator of progression and metastasis of cancer cells. Frontiers in Cell and Development Biology. 2017;5:18
  104. 104. Liu T, Chopra AK. An enteric pathogen Salmonella enterica serovar Typhimurium suppresses tumor growth by downregulating CD44high and CD4T regulatory (Treg) cell expression in mice: The critical role of lipopolysaccharide and Braun lipoprotein in modulating tumor growth. Cancer Gene Therapy. 2010;17(2):97-108
  105. 105. Fallarino F, Grohmann U, Puccetti P. Indoleamine 2,3-dioxygenase: From catalyst to signaling function. European Journal of Immunology. 2012;42(8):1932-1937
  106. 106. Munn DH. Indoleamine 2,3-dioxygenase, tumor-induced tolerance and counter-regulation. Current Opinion in Immunology. 2006;18(2):220-225
  107. 107. O'Donnell H, McSorley SJ. Salmonella as a model for non-cognate Th1 cell stimulation. Frontiers in Immunology. 2014;5:621
  108. 108. Saccheri F, Pozzi C, Avogadri F, Barozzi S, Faretta M, Fusi P, Rescigno M. Bacteria-induced gap junctions in tumors favor antigen cross-presentation and antitumor immunity. Science Translational Medicine. 2010;2(44):44ra57
  109. 109. Oviedo-Orta E, HE W. Gap junctions and connexin-mediated communication in the immune system. Biochimica et Biophysica Acta. 2004;1662(1-2):102-112
  110. 110. Matsue H, Yao J, Matsue K, Nagasaka A, Sugiyama H, Aoki R, Kitamura M. S S: Gap junction-mediated intercellular communication between dendritic cells (DCs) is required for effective activation of DCs. Journal of Immunology. 2006;176(1):181-190
  111. 111. Shilling DA, Smith MJ, Tyther R, Sheehan D, England K, Kavanagh EG, Redmond HP, Shanahan F, O'Mahony L. Salmonella typhimurium stimulation combined with tumour-derived heat shock proteins induces potent dendritic cell anti-tumour responses in a murine model. Clinical and Experimental Immunology. 2007;149(1):109-116

Written By

Marco A. Hernández-Luna, Paola Muñóz-López, Carlos A. Aguilar- González and Rosendo Luria-Pérez

Submitted: 01 November 2017 Reviewed: 15 February 2018 Published: 18 July 2018