Therapy For Colorectal Carcinoma Research Articles

Abstract B012: Preclinical study of Kiatomab, a novel monoclonal antibody to the cancer stem cell surface marker KIAA1114, for anti-cancer therapy in colorectal carcinoma

Abstract Most targeted therapy drugs block the growth of cancer cells by targeting specific molecules needed for tumor growth. Among targeted therapy drugs, cetuximab, the monoclonal antibody which binds to epidermal growth factor receptor (EGFR) and inhibits downstream signaling of EGFR, has greatly improved the median survival of patients with metastatic colorectal cancer (CRC). Yet, cetuximab showed limited therapeutic effect in CRC patients who carry certain mutation in the KRAS, which emphasizes the necessity of developing new targeted therapy drugs for CRC. KIA1114 is a full-length protein of the trophinin gene and is localized on the cell surface. In our previous research, we identified the role of KIA1114 as a novel surface marker of tumor initiating cells of hepatocellular carcinoma (HCC) by developing Kiatomab, KIA1114-specific monoclonal antibody. Here, we show that KIA1114 is also highly expressed in various CRC cells with mouse or human origin. Kiatomab treatment inhibits tumor growth in a syngeneic graft CRC mouse model in antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) dependent manner. In the metastatic CRC model, Kiatomab therapy suppresses metastasis, with a significant increase of survival. Of note, the anticancer efficacy of Kiatomab is further improved by combinatorial treatment with the standard chemotherapeutic agent cyclophosphamide (CTX), in both metastatic and solid tumor models. In summary, our findings suggest that KIAA1114 is a new target for CRC and its monoclonal antibody Kiatomab might have a potential for anticancer therapy. Citation Format: Young Min Kim, Sae Won Kim, Seungwon Lee, Hyekang Kim, Ji-Hae Kim, Han Wook Park, Young Chul Sung, Seung-Woo Lee. Preclinical study of Kiatomab, a novel monoclonal antibody to the cancer stem cell surface marker KIAA1114, for anti-cancer therapy in colorectal carcinoma [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B012.

1088P - Comprehensive assessment of the feasibility of adoptive cell therapy in colorectal carcinoma

1088P - Comprehensive assessment of the feasibility of adoptive cell therapy in colorectal carcinoma

Expression of Wntless in colorectal carcinomas is associated with invasion, metastasis, and poor survival.

Wntless also known as WLS, GPR177, or Evi, is a key modulator of Wnt protein secretion. Its overexpression is found in certain types of human cancers such as malignant astrocytoma and breast cancers. We hypothesized that this protein may be aberrantly expressed in colorectal carcinoma which also possesses aberrant Wnt signaling. To investigate the association between the expression of Wnt and clinicopathological parameters in colorectal carcinomas, a set of colorectal carcinoma tissue samples was analyzed for the expression of WLS using an anti-GPR177 monoclonal antibody specific for the WLS protein. High expression of WLS protein was observed in most colorectal carcinoma samples compared with nontumor mucosa in the same patients (117/201, 58.2%). High expression of WLS was associated with sex (p = 0.005), age (p = 0.009), depth of invasion (p < 0.001), lymph node metastasis (p = 0.026), and tumor-node-metastasis (TNM) stage (p = 0.003). No significant relationship between the expression of WLS and tumor location, size, and differentiation was found. The survival analyses showed WLS was an independent prognostic marker and that patients whose carcinoma exhibited high expression of WLS had a poorer outcome (p = 0.033). Our results indicate that WLS may play a role in invasion and metastasis of colorectal carcinoma. The WLS protein expression level may be used as a potential prognostic marker in colorectal carcinoma. Furthermore, the WLS gene may provide a novel target for therapy of colorectal carcinoma.

MicroRNAs in colorectal carcinoma - from pathogenesis to therapy

BackgroundActing as inflammatory mediators, tumor oncogenes or suppressors, microRNAs are involved in cell survival, death, epithelial–mesenchymal transition and metastasis, etc. Investigating the communication between microRNAs and tumorigenesis is critical to our understanding of the pathogenesis of multiple disease states.Main bodyCurrently, colorectal carcinoma (CRC), one of the most common malignancies worldwide, has a poor prognosis due to lack of an effective therapeutic option. Increasing evidence has identified altered profiles and regulatory potential of microRNAs in conditions related to environmentally-caused colorectal inflammation and colitis-associated cancer. Many studies have shed light on a more thorough understanding of the function and distribution of microRNAs in CRC initiation and emergence. However, the molecular mechanisms by which microRNAs modulate cellular processes still need to be further elucidated and may offer a foundation for evaluating microRNA-based therapeutic potential for CRC in both animal models and clinical trials.ConclusionIn this review, the roles and mechanisms of microRNAs involved in CRC from pathogenesis to therapy are summarized and discussed, which may provide more useful hints for CRC prevention and therapy.

Epitelial-to-mesenchimal transition and invasion are upmodulated by tumor-expressed granzyme B and inhibited by docosahexaenoic acid in human colorectal cancer cells.

BackgroundGranzyme B (GrB) is a serine protease, traditionally known as expressed by cytotoxic lymphocytes to induce target cell apoptosis. However, it is emerging that GrB, being also produced by a variety of normal and neoplastic cells and potentially acting on multiple targets, might represent a powerful regulator of a wide range of fundamental biological processes. We have previously shown that GrB is expressed in urothelial carcinoma tissues and its expression is associated to both pathological tumor spreading and EMT. We have also shown that docosahexaenoic acid (DHA), a dietary ω-3 polyunsaturated fatty acid with anti-tumor activity, while inhibiting urothelial and pancreatic carcinoma cell invasion also inhibited their GrB expression in vitro. In this study, we characterized a panel of colorectal carcinoma (CRC) cells, with different invasive capabilities, for GrB expression and for the contribution of GrB to their EMT and invasive phenotype. In addition, we investigated the effect of DHA on CRC cell-associated GrB expression, EMT and invasion.MethodsThe expression levels of GrB and EMT-related markers were evaluated by Western blotting. GrB knockdown was performed by Stealth RNAi small interfering RNA silencing and ectopic GrB expression by transfection of human GrB vector. Cell invasion was determined by the BioCoat Matrigel invasion chamber test.ResultsGrB was produced in 57.1 % CRC cell lines and 100 % CRC-derived Cancer Stem Cells. Although GrB was constitutive expressed in both invasive and noninvasive CRC cells, GrB depletion in invasive CRC cells downmodulated their invasion in vitro, suggesting a contribution of GrB to CRC invasiveness. GrB loss or gain of function downmodulated or upmodulated EMT, respectively, according to the analysis of cancer cell expression of three EMT biomarkers (Snail1, E-cadherin, N-cadherin). Moreover, TGF-β1-driven EMT was associated to the enhancement of GrB expression in CRC cell lines, and GrB depletion led to downmodulation of TGF-β1-driven EMT. In addition, DHA inhibited GrB expression, EMT and invasion in CRC cells in vitro.ConclusionsThese findings present a novel role for GrB as upmodulator of EMT in CRC cells. Moreover, these results support the use of DHA, a dietary compound without toxic effects, as adjuvant in CRC therapy.

Modified mismatch polymerase chain reaction-restriction fragment length polymorphism detected mutations in codon 12 and 13 of exon 2 of K-ras gene in colorectal cancer patients and its association with liver metastases: Data from a South Asian country.

Mutations in K-ras codon 12 and 13 of exon 2 are known to affect prognosis and impart resistance to anti-epidermal growth factor monoclonal antibody therapy in colorectal carcinoma (CRC). Our aim was to investigate the utility value of modified mismatch polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay to detect mutation in K-ras codons of CRC patients and to relate the mutational status to liver metastasis. Mismatch PCR-RFLP was developed to detect K-ras mutations in DNA isolated from paraffinized tumor tissue of thirty CRC patients. All patients had 5 year follow-up data to detect liver metastasis. Cross-tabulations were generated between K-ras mutations and the metastatic status. The Chi-square test was used to indicate statistical significance of the association. Of the 30 CRC patients investigated, K-ras mutations of codons 12 and/or 13 of exon 2 were detected in 14 (46.6%). Meanwhile, 13 patients (43.3%) were observed to have developed liver metastases. There was a significant association between the presence of the K-ras mutation in codon 12 and the occurrence of liver metastasis (χ2 = 4.693, P = 0.030) on the contrary to the mutation in codon 13 to which such occurrence of liver metastases was not seen (χ2 = 1.884, P = 0.169). Codon 12 of exon 2 of K--ras gene detected by modified mismatch PCR-RFLP assay is significantly associated with liver metastasis in CRC patients during the first 5 years after surgery. Thus, modified mismatch PCR-RFLP protocol is a suitable method in this setting to detect K-ras gene mutations predicting liver metastasis in CRC patients.

Curcumol Inhibits Growth and Induces Apoptosis of Colorectal Cancer LoVo Cell Line via IGF-1R and p38 MAPK Pathway.

Curcumol, isolated from the traditional medical plant Rhizoma Curcumae, is the bioactive component of Zedoary oil, whose potential anti-tumor effect has attracted considerable attention in recent years. Though many researchers have reported curcumol and its bioactivity, the potential molecular mechanism for its anti-cancer effect in colorectal cancer LoVo cells still remains unclear. In the present study, we found that curcumol showed growth inhibition and induced apoptosis of LoVo cells in a dose- and time-dependent manner. The occurrence of its proliferation inhibition and apoptosis came with suppression of IGF-1R expression, and then increased the phosphorylation of p38 mitogen activated protein kinase (MAPK), which might result in a cascade response by inhibiting the CREB survival pathway and finally triggered Bax/Bcl-2 and poly(ADP-ribose) polymerase 1 (PARP-1) apoptosis signals. Moreover, curcumol inhibited colorectal cancer in xenograft models of nude mice. Immunohistochemical and Western blot analysis revealed that curcumol could decrease the expression of ki-67, Bcl-2 as well as CREB1, and increase the expression of Bax and the phosphorylation of p38, which were consistent with our in vitro study. Overall, our in vitro and in vivo data confirmed the anti-cancer activity of curcumol, which was related to a significant inhibition of IGF-1R and activation of p38 MAPKs, indicating that curcumol may be a potential anti-tumor agent for colorectal carcinoma therapy.

Autophagy-based survival prognosis in human colorectal carcinoma.

The role of autophagy in cancers is controversial. Here we aim to determine the prognostic significance of autophagy in colorectal carcinoma patients, thereby allowing more rational development of therapeutic strategies. Through transmission electron microscopy, our data first demonstrated high frequency of defective mitochondria was strongly associated with poor overall survival in colorectal carcinoma. Next immunohistochemical study showed the expressions of Beclin 1, LC3B and Bcl-xL in both the center of tumor and adjacent noncancerous mucosal region were also correlated with overall survivals. We developed an autophagy signature for prognosis based on these three major autophagic proteins, further analysis suggested it was an independent prognostic biomarker and had its value even within single clinical stage. Combined TNM stage and this signature could significantly improve the accuracy of survival prognosis. To validate these immunohistochemical results, an internal testing cohort and an independent population were also included. Our findings suggest that autophagy plays an important role in the clinical cancer progression. Therefore autophagic proteins may be valuable prognostic biomarkers in the therapy of colorectal carcinoma and possibly other types of cancers.

The surgical treatment of patients with colorectal cancer and liver metastases in the setting of the "liver first" approach.

A surgical resection is the only curative method in the therapy of colorectal carcinoma and liver metastases. Along with the development of interventional radiological techniques the indications for surgery widen. The number of metastases and patients age should not present a contraindication for surgical resection. However, there are still some doubts concerns what to resect first in cases of synchronous colorectal carcinoma and liver metastases and how to ensure the proper remnant liver volume in order to avoid postoperative liver failure and achieve the best results. Through this review the surgical therapy of colorectal carcinoma and liver metastases was revised in the setting of "liver-first" approach and the problem of ensuring of remnant liver volume.

Enhanced anti-colorectal cancer effects of carfilzomib combined with CPT-11 via downregulation of nuclear factor-κB in vitro and in vivo.

Upregulation of nuclear factor-κB (NF-κB) in colorectal carcinoma (CRC) accelerates tumor growth, whereas, irinotecan (CPT-11)-induced NF-κB activation reduces chemosensitivity and weakens the anti-colorectal cancer function itself, while proteasome inhibitors can inhibit NF-κB and improve the effect of chemotherapy. Carfilzomib (CFZ) is a novel proteasome inhibitor that has been recently approved by the FDA and is in clinical use for the treatment of multiple myeloma, but little is known about its activity against CRC. The aim of the present study was to explore whether CFZ alone or in combination with CPT-11 is effective in CRC treatment. We evaluated the novel therapeutic ability and mechanism of action of CFZ in CRC in vitro and in vivo. SW620 cells were incubated with CFZ alone or in combination with CPT-11. Cell proliferation was assessed by WST-1 and clonogenic assays, the cytotoxic interaction was assessed with a combination index (CI). Cell cycle progression was analysed with flow cytometry. Cell apoptosis was evaluated by detecting the Annexin V/propidium iodide (PI) ratio, caspase 3 and CD95 expression, and with TUNEL staining. Cell migration and invasion was determined with a wound-healing assay and a Transwell matrix penetration assay. A CRC xenograft model was established to monitor tumor growth. EMSA was used to analyse NF-κB activation and western blot analysis was used to detect the protein levels of related signaling factors. CFZ significantly inhibited the growth of SW620 cells, and had synergistic inhibitory effects with CPT-11 on survival and colony formation; possibly by inhibition of NF-κB activation, MEK/ERK and PI3K/AKT pathway factor dephosphorylation and survivin downregulation. Co-administration of CFZ and CPT-11 induced G2/M arrest, increased p21WAF1/CIP, and decreased mutant p53 and cdc25c expression. Induction of apoptosis was accompanied by marked increases in PARP cleavage, caspase 3 activation, an increase of CD95 and p-p38, and ATF3 activation. Combination treatment lowered the invasive and migration ability of SW620 cells, reduced MMP and increased TIMP protein expression. Finally, co-administration of CFZ and CPT-11 suppressed tumor growth and increased apoptosis compared with single-agent treatment in SW620 xenograft models correlated with NF-κB downregulation. Carfilzomib alone or in combination with CPT-11 is effective against colorectal cancer through inhibition of multiple mechanisms related to NF-κB, and could be a potential novel therapy for CRC.

IL-23 selectively promotes the metastasis of colorectal carcinoma cells with impaired Socs3 expression via the STAT5 pathway

Interleukin-23 (IL-23) is a conventional proinflammatory IL related to colorectal carcinoma (CRC). The signal transducer and activator of transcription (STAT) and suppressors of cytokine signaling (Socs) molecules, respectively, serve as agonists and antagonists of IL-23-associated inflammation. However, it remains unknown whether IL-23 directly affects CRC metastasis. In this study, we measured the metastasis of several human CRC cell lines stimulated by IL-23 in vitro and in vivo. Interestingly, the prometastasis effect of IL-23 was observed only in SW-620 cells. IL-23-associated migration and invasion was mediated by the phosphorylation of STAT5. The expression of Socs3 in SW-620 was impaired by IL-23 via DNA methylation and DNA methyltransferase-1 (DNMT-1)-dependent way. The DNMT-1-associated regulation was not observed in the other three cells. Socs3 was further confirmed to inhibit the prometastatic function of IL-23 both in vitro and in vivo. We analyzed the clinical correlation between the level of IL-23 in tumors and the metastasis of CRC and found that higher IL-23 levels along with lower Socs3 in CRC tissues accounted for more metastatic cases. In conclusion, it was demonstrated that IL-23, assisted by STAT5, might only promote the metastasis of CRC with deficient Socs3 expression in which IL-23-induced DNMT-1 was involved. It was elucidated that Socs3 seemed to be one of the important factors that mediate the selectivity of IL-23. Taken together, these discoveries give rise to new insights into the role of IL-23 in cancer biology and provide additional preclinical data regarding IL-23-associated therapy for CRC.

S100A6 stimulates proliferation and migration of colorectal carcinoma cells through activation of the MAPK pathways

The S100A6 protein, a member of the S100 protein family, is overexpressed in many tumors including colorectal carcinoma (CRC). Although recent studies showed that the elevated expression of S100A6 was associated with the stage and lymphatic permeation of CRC, little is known about whether and how S100A6 contributes to CRC development. Here we investigated the S100A6 expression in CRC tissues and cell lines, and explored the molecular mechanisms underlying the role of S100A6 in CRC development by examining cell proliferation and migration invitro, and tumorigenicity in nude mice. The results show that S100A6 expression was markedly increased in CRC tissues and cell lines compared to normal colon tissues and a normal colon mucosal epithelial cell line, respectively. Recombinant adenovirus-mediated overexpression of S100A6 or treatment with recombinant S100A6 protein in HCT116, a CRC cell line with relative low S100A6 expression, resulted in enhanced cell proliferation and migration, and the mitogen-activated protein kinase (MAPK) activation invitro, and tumor growth invivo. Conversely, RNAi-mediated knockdown of S100A6 in LoVo, a CRC cell line with relative high S100A6 expression, resulted in reduced cell proliferation, migration and MAPK activity. S100A6-induced proliferation was partially attenuated by an ERK inhibitor while migration was suppressed by a p38 inhibitor. Taken together, our results suggest that the cellular effects of S100A6 are mediated by the ERK and p38 MAPK pathways, and modulation of these pathways may be employed for CRC prevention and therapy.

Fibroblast Growth Factor Receptor-2 IIIc as a Novel Molecular Target in Colorectal Cancer

The prognosis of patients with colorectal carcinoma (CRC) is unfavorable once the disease has progressed to an unresectable stage. A high percentage of CRCs overexpress a number of growth factors and their receptors, including fibroblast growth factor receptor (FGFR). Expression of FGFR-2 IIIc, a splicing isoform of FGFR-2, correlated with distant metastasis and poor prognosis in CRC cases. FGFR-2 IIIc-transfected CRC cells showed increased cell growth, soft agar colony formation, migration, and invasion, as well as decreased adhesion to extracellular matrices. The administration of humanized anti-FGFR-2 IIIc monoclonal antibody inhibited CRC cell growth and migration. FGFR-2 IIIc might contribute to the aggressive growth of certain cancers, including CRC, and is a novel candidate for molecular targeted cancer therapies. In this article, we summarize the recent development of standardized treatments and molecular targeted therapies for CRC, with a focus on FGFR-2 IIIc.

Notch1-dependent regulation of p27 determines cell fate in colorectal cancer

Enhanced Notch signaling contributes to uncontrolled cell growth and cell death resistance in cancer. Here, we demonstrate that in colorectal carcinoma cells the Notch1-dependent activation of cell cycle and proliferation is mediated by repression of the cyclin-dependent kinase inhibitor (CDKI) p27. The half-life of p27 significantly increased after siRNA‑mediated knockdown of Notch1. Notch1 depletion altered the transcription of SKP2, KPC1 and KPC2, which are E3-ubiquitin ligase subunits targeting p27 for proteasomal degradation in the nucleus and the cytoplasm, respectively. As a consequence, the levels of p27 in both cellular fractions were elevated upon Notch1 knockdown. Importantly, the downregulation of Notch1 significantly sensitized colorectal cancer cells to chemotherapy and ionizing radiation. Our findings support an important role of p27 in Notch1-dependent oncogenic signaling and suggest that Notch1 is a promising target for an experimental therapy of colorectal carcinoma.

Synergistic and individual effects of umbelliferone with 5-fluorouracil on tumor markers and antioxidant status of rat treated with 1,2-dimethylhydrazine

PurposeColorectal cancer (CRC) is among the most common malignancies worldwide. Early diagnosis of the progressive tumor disease and control of the effect of therapy in colorectal carcinoma are most frequently performed. MethodsThe purpose of this present work was to evaluate the synergistic responses of a novel chemopreventive combination regimen namely 5-FU and natural coumarin family, UMB to assess the serum tumor markers CEA, CA 19-9 and CA 72-4 for colorectal carcinoma is described according to recently formulated guidelines, in addition of antioxidant and lipid peroxidation status in the serum of 1,2-dimethylhydrazine induced rat colon carcinogenesis. ResultsAdministration of DMH resulted in decreased serum levels of antioxidants such as GST, SOD, CAT, GPx, GR, GSH and lipid peroxidation end products such as TBARS, LOOH and CD with concomitant increase in the levels of colon cancer specific serum markers like CEA, CA 19-9 and CA 72-4 levels. Administration of UMB alone and combined forms of UMB with 5-FU to the colon cancer-bearing rats significantly attenuated these alterations which indicates the anticancer effect that was further confirmed by histopathological analysis. ConclusionsOverall, these findings substantiate the synergistic potential of UMB with 5-FU against chemically-induced colon cancer in rats.

Berberine inhibits the growth of human colorectal adenocarcinoma in vitro and in vivo

Berberine is an alkaloid isolated from the Chinese herbal medicine Huanglian, and has long been used as an antibiotic. Its antineoplastic properties were subsequently discovered in vitro. The purpose of this study was to investigate the effects of berberine on the growth of human colorectal carcinoma cells in vitro and in vivo. The results showed that berberine inhibited human colorectal adenocarcinoma (LoVo) cell growth in a time- and dose-dependent manner. A WST-1 assay showed that the IC50 value after 72 h was 40.79 ± 4.11 μM. Cell cycle analysis of 40 μM berberine-treated LoVo cells by flow cytometry showed accumulation of cells in the G2/M phase. The inhibition of LoVo cell growth by berberine was associated with the suppression of cyclin B1, cdc2, and cdc25c proteins. Berberine at a dose of 50 mg kg(-1) day(-1) showed inhibitory rates of 45.3% in a human colorectal adenocarcinoma xenograft in nude mice. The combination of berberine and 5-fluorouracil (5-FU) had a higher inhibitory rate (59.8%) than the berberine group (36.4%, P = 0.01), but no significant difference was observed between the 5-FU group (43.0%, P = 0.06) and the combination group. These results support the possibility that berberine may be useful as an alternative therapy for colorectal carcinoma.

Abstract 2293: KLF5 is essential for oncogenesis of intestinal tumors and control of intestinal stem cells.

Abstract Genetic changes in intestinal epithelial stem cells are more important for oncogenesis of intestinal tumors than such changes in non-stem cells. A large-scale sequencing analysis of human colorectal carcinoma (CRC) revealed that Wnt/β-catenin signal activation is the most frequent genomic changes (92-97%) in human colorectal carcinoma (CRC). However, fundamental significance of its signal activation of intestinal stem cells is still remains unsolved. Kruppel-like factor 5 (KLF5) is one of KLF zinc finger transcription factor with diverse biological functions. KLF5 has stronger expression in the bottom of intestinal crypts, where the stem cells reside, and weaker expression in villi as the epithelial cells differentiate into more mature cells, which is complementary pattern of KLF4. KLF5 is implicated in the renewal and maintenance of ES cells, and has the potential to induce iPS cells, although weaker than KLF4. In this study, we found that inducible deletion of KLF5, specifically in Lgr5+ intestinal epithelial stem cells, suppressed the proliferation and nuclear localization of β-catenin, and generated some apoptotic cells in the intestinal crypts of mice. Furthermore, we demonstrated that inducible deletion of KLF5 in all intestinal epithelia caused mislocalization of Paneth cells, which constitute the stem cell niche. These data indicate that KLF5, rather than KLF4, is required for the maintenance and differentiation of Lgr5+ intestinal stem cells. Moreover, we detected frequent genome amplification at the KLF5 locus in human colorectal cancers (CRCs), and enhanced expression of KLF5 in CRC samples. In mice, Lgr5+ stem cell-specific induction of an active β-catenin mutant generated severe lethal adenomas and carcinomas. By contrast, when the induction of active β-catenin was performed simultaneously with deletion of KLF5 in stem cells, oncogenesis was almost completely suppressed. The simultaneous deletion of KLF5 under the induction of the active mutant of β-catenin in the stem cells suppressed the transcription of HDAC1and Sphk1, which promotes CRCs, and upregulated the transcription of Aim2 and Foxo3, tumor suppressors in CRCs, in both the FACS sorted stem cells and the transit amplifying cells. These results indicate that oncogenesis of intestinal tumors induced by Wnt/β-catenin signal activation (92-97% in CRCs) in stem cells requires KLF5, as in the case of Myc, and that KLF5 is also an essential controlling factor for homeostatic turnover and maintenance, niche formation, and differentiation of the intestinal epithelial stem cells. These suggest that KLF5 is a promising target oncogene for CRC therapy directed at colon cancer stem cells. Citation Format: Takeo Nakaya, Masahiko Kuroda, Ryozo Nagai. KLF5 is essential for oncogenesis of intestinal tumors and control of intestinal stem cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2293. doi:10.1158/1538-7445.AM2013-2293

Exploiting monocarboxylate transporters as new molecular targets for colorectal carcinoma therapy

Background Tumour cells relies mostly on glycolysis to meet their energetic demands thus leading to an overload of lactic acid, which must be exported to the extracellular milieu, through the monocarboxylate transporters (MCTs). Due to their upregulation in cancer, MCTs are currently seen as promising therapeutic targets in cancer. Colorectal carcinoma (CRC) is the second most common type of cancer worldwide, being mainly a disease of industrialized countries. Among the chemotherapeutic agents used in the treatment of CRC, 5-fluorouracil (5-FU) is one of the most efficient, although resistance to 5-FU treatment has been reported. We aimed at understanding the role of MCTs in the glycolytic metabolism of CRC and exploring these transporters as putative therapeutic targets.

Research development of the relationship between thymidine phosphorylase expression and colorectal carcinoma.

Thymidine phosphorylase (TP) is a key enzyme that contributes to the composition and decomposition of pyrimidine nucleotides. TP seems homologous to platelet-derived endothelial cell growth factor, and its effects on inducing vascularization and anti-apoptosis are closely related to growth and metastasis of colorectal carcinoma. In addition, TP is a key enzyme that catalyzes the transformation from 5-fluorouracil (FU) prodrugs of 5′-deoxy-5-fluorouridine (5′-DFUR) to 5-FU. The activity of TP is closely related to the sensitivity of colorectal carcinoma cells to fluorouracil drugs and targeted therapy. Given the important functions of TP in growth, metastasis, tumor treatment, and prognosis, determining its expression mechanism is significant. This article summarizes the research development of TP expression in colorectal carcinoma, tumor neovascularization, cytotoxicity activation of 5′-DFUR, and colorectal carcinoma therapy.

Acetate-induced apoptosis in colorectal carcinoma cells involves lysosomal membrane permeabilization and cathepsin D release

Colorectal carcinoma (CRC) is one of the most common causes of cancer-related mortality. Short-chain fatty acids secreted by dietary propionibacteria from the intestine, such as acetate, induce apoptosis in CRC cells and may therefore be relevant in CRC prevention and therapy. We previously reported that acetic acid-induced apoptosis in Saccharomyces cerevisiae cells involves partial vacuole permeabilization and release of Pep4p, the yeast cathepsin D (CatD), which has a protective role in this process. In cancer cells, lysosomes have emerged as key players in apoptosis through selective lysosomal membrane permeabilization (LMP) and release of cathepsins. However, the role of CatD in CRC survival is controversial and has not been assessed in response to acetate. We aimed to ascertain whether LMP and CatD are involved in acetate-induced apoptosis in CRC cells. We showed that acetate per se inhibits proliferation and induces apoptosis. More importantly, we uncovered that acetate triggers LMP and CatD release to the cytosol. Pepstatin A (a CatD inhibitor) but not E64d (a cathepsin B and L inhibitor) increased acetate-induced apoptosis of CRC cells, suggesting that CatD has a protective role in this process. Our data indicate that acetate induces LMP and subsequent release of CatD in CRC cells undergoing apoptosis, and suggest exploiting novel strategies using acetate as a prevention/therapeutic agent in CRC, through simultaneous treatment with CatD inhibitors.