Genetic variants as potential predictive biomarkers in advanced colorectal cancer patients treated with oxaliplatin-based chemotherapy

In silico analysis to identify miR-1271-5p/PLCB4 (phospholipase C Beta 4) axis mediated oxaliplatin resistance in metastatic colorectal cancer

Oxaliplatin (OXA) is the first-line chemotherapy drug for metastatic colorectal cancer (mCRC), and the emergence of drug resistance is a major clinical challenge. Although there have been numerous studies on OXA resistance, but its underlying molecular mechanisms are still unclear. This study aims to identify key regulatory genes and pathways associated with OXA resistance. The Gene Expression Omnibus (GEO) GSE42387 dataset containing gene expression profiles of parental and OXA-resistant LoVo cells was applied to explore potential targets. GEO2R, STRING, CytoNCA (a plug-in of Cytoscape), and DAVID were used to analyze differentially expressed genes (DEGs), protein-protein interactions (PPIs), hub genes in PPIs, and gene ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. R2 online platform was used to run a survival analysis of validated hub genes enriched in KEGG pathways. The ENCORI database predicted microRNAs for candidate genes. A survival analysis of those genes was performed, and validated using the OncoLnc database. In addition, the 'clusterProfiler' package in R was used to perform gene set enrichment analysis (GSEA). We identified 395 DEGs, among which 155 were upregulated and 240 were downregulated. In total, 95 DEGs were screened as hub genes after constructing the PPI networks. Twelve GO terms and three KEGG pathways (steroid hormone biosynthesis, malaria, and pathways in cancer) were identified as being significant in the enrichment analysis of hub genes. Twenty-one hub genes enriched in KEGG pathways were defined as key genes. Among them AKT3, phospholipase C Beta 4 (PLCB4), and TGFB1 were identified as OXA-resistance genes through the survival analysis. High expressions of AKT3 and TGFB1 were each associated with a poor prognosis, and lower expression of PLCB4 was correlated with worse survival. Further, high levels of hsa-miR-1271-5p, which potentially targets PLCB4, were associated with poor overall survival in patients with CRC. Finally, we found that PLCB4 low expression was associated with MAPK signaling pathway and VEGF signaling pathway in CRC. Our results demonstrated that hsa-miR-1271-5p/PLCB4 in the pathway in cancer could be a new potential therapeutic target for mCRC with OXA resistance.

Identification of KIF21B as a Biomarker for Colorectal Cancer and Associated with Poor Prognosis

OBJECTIVE

This study is aimed at exploring the function of KIF21B in colorectal cancer.

METHODS

The expression of KIF21B was analyzed by the UALCAN database, GEPIA site, and TIMER site. The survival rate was analyzed by Kaplan-Meier curves, and the prognosis was analyzed by ROC. Relevant signaling pathways and biological processes were analyzed by GO-KEGG enrichment analysis. The correlation between KIF21B and cancer immune infiltrates was analyzed by TIMER. The functional state of KIF21B in various types of cancers was conducted by single-cell RNA-sequencing. Furthermore, the expression of KIF21B was verified by real-time qPCR and Western blotting. The cell proliferation was measured by CCK8 assay. The cell apoptosis was analyzed by flow cytometry. Cell migration and invasion were determined by the transwell assay.

RESULTS

Combination analysis of bioinformatics methods revealed that KIF21B is high expression in CRC, associated with poor survival. KIF21B and associated genes were significantly enriched in covalent chromatin modification. The expression of KIF21B was positively correlated with infiltrating levels of CD4+ T cells and neutrophils, cell apoptosis, and metastasis. KIF21B was upregulated expression in CRC cell lines. KIF21B deficiency reduced cell proliferation, migration, and invasion.

CONCLUSIONS

Our study suggested that KIF21B may be a biomarker in CRC.

Circ_0082182 upregulates the NFIB level via sponging miR-326 to promote oxaliplatin resistance and malignant progression of colorectal cancer cells

Circular RNAs (circRNAs) are key regulators in tumor metastasis and drug resistance. This study was designed to investigate circ_0082182 function and mechanism in oxaliplatin (OXA) resistance and cancer progression of colorectal cancer (CRC). The circ_0082182, microRNA-326 (miR-326), and nuclear factor I B (NFIB) levels were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell sensitization was analyzed by Cell Counting Kit-8 assay. The proliferation ability was determined via EdU assay, and apoptosis was measured by flow cytometry. Transwell assay and wound healing assay were performed to assess cell invasion and migration. The protein level was examined through Western blot. The binding interaction was conducted via dual-luciferase reporter assay. Xenograft tumor assay was used to explore the circ_0082182 function in vivo. The circ_0082182 level was upregulated in OXA-resistant CRC samples and cells. Downregulation of circ_0082182 suppressed OXA resistance, proliferation, invasion, and migration but promoted apoptosis of OXA-resistant CRC cells. Circ_0082182 acted as a sponge for miR-326. The regulatory role of circ_0082182 was ascribed to the miR-326 sponging function. MiR-326 directly targeted NFIB to impede OXA resistance and cancer progression in CRC cells. NFIB level was regulated by circ_0082182 via sponging miR-326. Circ_0082182 promoted tumor growth in OXA-resistant xenograft tumor model through mediating the miR-326/NFIB axis. These data suggested that circ_0082182 elevated the NFIB expression to regulate OXA resistance and CRC progression by absorbing miR-326.

The dual role of microRNA-9 in gastrointestinal cancers: oncomiR or tumor suppressor?

microRNA are noncoding endogenous RNAs of ∼ 25-nucleotide, involved in RNA silencing and controlling of cell function. Recent evidence has highlighted the important role of various in the biology of human cancers. miR-9 is a highly conserved microRNA and abnormal regulation of miR-9 expression has various impacts on disease pathology. miR-9 may play a dual tumor-suppressive or oncomiR activity in several cancers. There have been conflicting reports concerning the role of miR-9 in gastrointestinal cancers. Several signaling pathways including PDK/AKT, Hippo, Wnt/β-catenin and PDGFRB axes are affected by miR-9 in suppressing proliferation, invasion and metastasis of tumor cells. Oncogenic miR-9 triggers migration, metastasis and clinic-pathological characteristics of patients with gastrointestinal malignancy by targeting various enzymes and transcription factors such as E-cadherin, HK2, LMX1A, and CDX2. On the other hand, long non-coding RNAs and circular RNAs can modulate miR-9 expression in human cancers. In this review, we aimed to summarize recent findings about the potential value of miR-9 in gastrointestinal tumors, that include: screening, prognostic and treatment.

Nanocarriers as a Tool for the Treatment of Colorectal Cancer

Nanotechnology is a promising tool for the treatment of cancer. In the past decades, major steps have been made to bring nanotechnology into the clinic in the form of nanoparticle-based drug delivery systems. The great hope of drug delivery systems is to reduce the side effects of chemotherapeutics while simultaneously increasing the efficiency of the therapy. An increased treatment efficiency would greatly benefit the quality of life as well as the life expectancy of cancer patients. However, besides its many advantages, nanomedicines have to face several challenges and hurdles before they can be used for the effective treatment of tumors. Here, we give an overview of the hallmarks of cancer, especially colorectal cancer, and discuss biological barriers as well as how drug delivery systems can be utilized for the effective treatment of tumors and metastases.

Exosomes: Emerging modulators of signal transduction in colorectal cancer from molecular understanding to clinical application

Exosomes are small cell derived membrane nano-vesicles that carry various components including lipids, proteins and nucleic acids. There is accumulating evidence that exosomes have a role in tumorigenesis, tumor invasiveness and metastasis. Furthermore, oncogene mutation may influence exosome release from tumor cells. Exosomes may induce colorectal cancer by altering signaling cascades such as the Wnt/β-catenin and KRAS pathways that are involved in cell proliferation, apoptosis, dissemination, angiogenesis, and drug resistance. The aim of this review was to overview recent findings evaluating the association between tumor cells-derived exosomes and their content in modulating signaling pathways in colorectal cancer.

Feng-Liao-Chang-Wei-Kang Combined with 5-Fluorouracil Synergistically Suppresses Colitis-Associated Colorectal Cancer via the IL-6/STAT3 Signalling Pathway

Background

Colitis-associated colorectal cancer (CAC) develops from active colonic inflammation, which is characterized by the production of proinflammatory cytokines that can induce mutations. IL-6 is produced by multiple cell types located within the tumor microenvironment including tumor-infiltrating immune cells, stromal cells, and the tumor cells themselves. The aim of our study was to explore the mechanism of Feng-Liao-Chang-Wei-Kang (FLCWK) and 5-fluorouracil (5-FU) in treating CAC.

Method

HCT116 cells were treated with 5-FU in the absence or presence of FLCWK. Cell proliferation was assayed by MTT assays. Apoptosis and the cell cycle phases were detected by flow cytometry. Western blotting and Q-PCR assays were used to detect the expression levels of proteins and genes related to the IL-6/STAT3 signalling pathway. A mouse model for CAC was established by treating animals with 12.5 mg/kg azoxymethane (AOM) followed by 3 cycles of 2.5% dextran sodium sulphate (DSS). The associated pathological changes were determined after haematoxylin and eosin (H&E) staining. The expression of related proteins and genes in various tissues was examined using immunofluorescence techniques.

Results

FLCWK enhanced the ability of 5-FU to promote apoptosis by inhibiting the proliferation of HCT116 cells and blocking the IL-6/STAT3 pathway. FLCWK combined with 5-FU reduced the number and size of colon tumors in mice with CAC and significantly increased their survival rate. In the CAC model, FLCWK synergized with 5-FU to inhibit the phosphorylation of STAT3, preventing IL-6/STAT3 signal transduction and thus further inducing apoptosis and inhibition of colon cancer cell proliferation.

Conclusion

FLCWK can inhibit the activation of STAT3 by reducing the production of IL-6, thereby increasing the occurrence of colitis-related colorectal cancer with 5-FU.

Asiaticoside suppresses cell proliferation by inhibiting the NF‑κB signaling pathway in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-associated mortality. Asiaticoside (AC) exhibits antitumor effects; however, to the best of our knowledge, the biological function of AC in CRC cells remains unclear. Therefore, the aim of the present study was to investigate the effect of AC on CRC cells. In the present study, CCK-8 and colony formation assays were performed to assess the effects of AV on human CRC cell lines (HCT116, SW480 and LoVo). Mitochondrial membrane potential was examined by JC-1 staining. Cell apoptosis and cell cycle were monitored by flow cytometry, and the expression of genes was evaluated using RT-qPCR and western blot analysis. Furthermore, the biological effect of AC in vivo was detected using a xenograft mouse model. The findings revealed that 2 µM AC suppressed the proliferation of CRC cells in a time- and dose-dependent manner, but had no adverse effects on normal human intestinal FHC cells at a range of concentrations. AC decreased the mitochondrial membrane potential and increased the apoptosis of CRC cells in a dose-dependent manner. Furthermore, AC induced cell cycle arrest at the G0/G1 phase. AC attenuated IκBα phosphorylation in a dose-dependent manner, thereby preventing P65 from entering the nucleus, and resulting in inhibition of the NF-κB signaling pathway. In addition, AC significantly reduced the expression of CDK4 and Cyclin D1 in a dose-dependent manner, significantly upregulated the activation of caspase-9 and caspase-3, and decreased the Bcl-2/Bax mRNA ratio. Furthermore, treatment with the NF-κB signaling pathway inhibitor JSH-23 significantly increased the cytotoxicity of AC in CRC cells. Findings of the xenograft mice model experiments revealed that AC significantly inhibited colorectal tumor growth in a dose-dependent manner. Overall, AC suppressed activation of the NF-κB signaling pathway by downregulating IκBα phosphorylation. This resulted in inhibition of CRC cell viability and an increase of cell apoptosis, which may form the basis of AC use in the treatment of patients with CRC.

A role of the 53BP1 protein in genome protection: structural and functional characteristics of 53BP1-dependent DNA repair

Nuclear architecture plays a significant role in DNA repair mechanisms. It is evident that proteins involved in DNA repair are compartmentalized in not only spontaneously occurring DNA lesions or ionizing radiation-induced foci (IRIF), but a specific clustering of these proteins can also be observed within the whole cell nucleus. For example, 53BP1-positive and BRCA1-positive DNA repair foci decorate chromocenters and can appear close to nuclear speckles. Both 53BP1 and BRCA1 are well-described factors that play an essential role in double-strand break (DSB) repair. These proteins are members of two protein complexes: 53BP1-RIF1-PTIP and BRCA1-CtIP, which make a “decision” determining whether canonical nonhomologous end joining (NHEJ) or homology-directed repair (HDR) is activated. It is generally accepted that 53BP1 mediates the NHEJ mechanism, while HDR is activated via a BRCA1-dependent signaling pathway. Interestingly, the 53BP1 protein appears relatively quickly at DSB sites, while BRCA1 is functional at later stages of DNA repair, as soon as the Mre11-Rad50-Nbs1 complex is recruited to the DNA lesions. A function of the 53BP1 protein is also linked to a specific histone signature, including phosphorylation of histone H2AX (γH2AX) or methylation of histone H4 at the lysine 20 position (H4K20me); therefore, we also discuss an epigenetic landscape of 53BP1-positive DNA lesions.

Oxaliplatin-DNA Adducts as Predictive Biomarkers of FOLFOX Response in Colorectal Cancer: A Potential Treatment Optimization Strategy

FOLFOX is one of the most effective treatments for advanced colorectal cancer. However, cumulative oxaliplatin neurotoxicity often results in halting the therapy. Oxaliplatin functions predominantly via the formation of toxic covalent drug-DNA adducts. We hypothesize that oxaliplatin-DNA adduct levels formed in vivo in peripheral blood mononuclear cells (PBMC) are proportional to tumor shrinkage caused by FOLFOX therapy. We further hypothesize that adducts induced by subtherapeutic "diagnostic microdoses" are proportional to those induced by therapeutic doses and are also predictive of response to FOLFOX therapy. These hypotheses were tested in colorectal cancer cell lines and a pilot clinical study. Four colorectal cancer cell lines were cultured with therapeutically relevant (100 μmol/L) or diagnostic microdose (1 μmol/L) concentrations of [14C]oxaliplatin. The C-14 label enabled quantification of oxaliplatin-DNA adduct level with accelerator mass spectrometry (AMS). Oxaliplatin-DNA adduct formation was correlated with oxaliplatin cytotoxicity for each cell line as measured by the MTT viability assay. Six colorectal cancer patients received by intravenous route a diagnostic microdose containing [14C]oxaliplatin prior to treatment, as well as a second [14C]oxaliplatin dose during FOLFOX chemotherapy, termed a "therapeutic dose." Oxaliplatin-DNA adduct levels from PBMC correlated significantly to mean tumor volume change of evaluable target lesions (5 of the 6 patients had measurable disease). Oxaliplatin-DNA adduct levels were linearly proportional between microdose and therapeutically relevant concentrations in cell culture experiments and patient samples, as was plasma pharmacokinetics, indicating potential utility of diagnostic microdosing.

Upregulated OCT3 has the potential to improve the survival of colorectal cancer patients treated with (m)FOLFOX6 adjuvant chemotherapy

PURPOSE

To investigate the influence of organic cation transporter 3 (OCT3) expression on the effect of the combination regimen of 5-fluorouracil, folinic acid and oxaliplatin ((m)FOLFOX6) in colorectal cancer (CRC) patients.

METHODS

This is a retrospective study conducted at a single centre (Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, China). Patients with stage IIb-IV resectable CRC who were being postoperatively treated with (m)FOLFOX6 as a first-line adjuvant chemotherapy regimen for at least 5 cycles and had resected primary tumour samples available were eligible for the study. Patients who preoperatively received chemotherapy and/or radiotherapy or were treated with targeted drugs or other anticancer drugs were excluded from the study. Immunohistochemical staining and digital image analysis were used to assess OCT3 expression in tumour samples. According to OCT3 expression level, the receiver operating characteristic curve (ROC curve) was used to divide the patients into two groups. Cox proportional risk regression was performed with the forward LR (forward stepwise regression based on maximum likelihood estimation) method using SPSS17.0 software. The primary endpoint was the 2-year progression-free survival.

RESULTS

In total, 57 patients were included between 2014 and 2016 according to the inclusion and exclusion criteria (22 had low OCT3 expression, and 35 had high OCT3 expression). The mean age was 55.7 (30-74) years, and 37 of the total patients were male. According to TNM stage, 5 patients had stage IV disease, 44 patients had stage III disease, and 8 patients had stage II disease. Through Cox regression analysis, we found that among patients receiving the (m)FOLFOX6 regimen, those with higher OCT3 expression had a higher two-year progression-free survival rate than those with lower OCT3 expression (P = 0.038). The hazard ratio of patients with high OCT3 expression compared with patients with low OCT3 expression was 0.247. Besides, it was found that the age of patients was negatively correlated with expression level of OCT3, which can explain why patients over 70 years do not benefit from oxaliplatin-containing chemotherapy.

CONCLUSIONS

High OCT3 expression in CRC tissues may be a protective factor for CRC patients treated with (m)FOLFOX6.

Addition of Platinum Derivatives to Fluoropyrimidine-Based Neoadjuvant Chemoradiotherapy for Stage II/III Rectal Cancer: Systematic Review and Meta-Analysis

BACKGROUND

Current guidelines recommend neoadjuvant therapy for patients with stage II or III rectal cancer. The addition of platinum derivatives to fluoropyrimidine-based chemoradiotherapy has been frequently investigated, but their role in this setting remains controversial.

METHODS

PubMed, Cochrane Library, and Web of Science were systematically searched for randomized trials comparing chemoradiotherapy with or without platinum agents in stage II or III rectal cancer. Main outcome parameters were overall and disease-free survival, additional outcomes included pathological complete response, isolated local recurrence, distant recurrence, toxicity, and perioperative morbidity. Time-to-event data were pooled as hazard ratios (HRs) by the inverse variance method and binary outcomes as odds ratios (ORs) by the Peto method with their respective 95% confidence interval (CI). All statistical tests were two-sided.

RESULTS

Ten randomized controlled trials with data on 5599 patients were included in the meta-analysis. Platinum derivatives did not statistically significantly improve overall survival (HR = 0.93, 95% CI = 0.82 to 1.05, P = .23), disease-free survival (HR = 0.91, 95% CI = 0.83 to 1.01, P = .07), or local recurrence (OR = 0.83, 95% CI = 0.66 to 1.05, P = .12). However, it led to a statistically significant increase of pathological complete response (OR = 1.31, 95% CI = 1.10 to 1.55, P = .002) and a statistically significant reduction of distant recurrence (OR = 0.78, 95% CI = 0.66 to 0.92, P = .004). Benefits were accompanied by higher rates of grade 3 or 4 toxicities.

CONCLUSIONS

Intensified neoadjuvant chemoradiotherapy with the addition of platinum derivatives cannot be recommended routinely because it did not improve overall or disease-free survival and was associated with increased toxicity. It needs to be elucidated whether the benefits in distant recurrence and pathological complete response may be advantageous for selected high-risk patients.

The identification of CRNDE, H19, UCA1 and HOTAIR as the key lncRNAs involved in oxaliplatin or irinotecan resistance in the chemotherapy of colorectal cancer based on integrative bioinformatics analysis

With the increasing rate of chemoresistance in colorectal cancer (CRC) patients with advanced tumor stages, it is a matter of urgent importance to delineate the factors involved in the drug resistance process. In this study, gene expression profiles were downloaded from the Gene Expression Omnibus database and an integrated analysis with the aim of detecting hub long non‑coding RNAs (lncRNAs) and their regulated, differentially expressed genes (DEGs) during treatment with oxaliplatin (OxPt) or irinotecan was conducted. A total of seven differentially expressed lncRNAs were correlated with OxPt resistance and 21 were correlated with resistance to SN‑38, the active metabolite of irinotecan. Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis confirmed that drug resistance was strongly associated with an imbalance between cell proliferation and apoptosis, cell energetic metabolism under hypoxic conditions, and angiogenesis. Moreover, a large number of lncRNA‑targeted DEGs were located in extracellular exosomes. Further analyses identified four hub lncRNAs involved in the process of drug resistance, including CRNDE, H19, UCA1 and HOTAIR, which are predictive factors for treatment sensitivity. Among them, HOTAIR stands out as a strong factor, the elevated expression of which is also associated with advanced tumor node and metastasis stage and poor CRC disease prognosis.

Prognostic value of high mobility group protein A2 (HMGA2) over-expression in cancer progression

The high mobility group A2 (HMGA2; also called HMGI-C) gene is an architectural transcription factor that belonging to the high mobility group AT-hook (HMGA) gene family. HMGA2 is aberrantly regulated in several human tumors. Over-expression of HMGA2 is correlated with a higher risk of metastasis and an unfavorable prognosis in patients with cancer. We performed a meta-analysis to determine the clinic-pathological and prognostic value of HMGA2 overexpression in different human tumors. A comprehensive literature search was performed using PubMed, Embase, Cochrane Library, Scopus, MEDLINE, Google Scholar and ISI Web of Science. Hazard ratios (HRs)/odds ratios (ORs) and their 95% confidence intervals (CIs) were used to assess the strength of the association between HMGA2 expression and overall survival (OS)/progression free survival (PFS)/disease free survival (DFS). A total of 5319 patients with 19 different types of cancer from 35 articles were evaluated. Pooled data analysis indicated that increased HMGA2 expression in cancer patients predicted a poor OS (HR = 1.70; 95% CI = 1.6-1.81; P < 0.001; fixed-effect model). In subgroup analyses, high HMGA2 expression was particularly associated with poor OS in individuals with gastrointestinal (GI) cancer (HR = 1.89, 95% CI: 1.83-1.96; fixed-effect model) and HNSCC cancer (HR-1.78, 95%CI: 1.44-2.21; fixed-effect model). Over-expression of HMGA2 was associated with vascular invasion (OR = 0.16, 95% CI = 0.05-0.49; P = 0.001) and lymphatic invasion (OR = 1.89, 95% CI = 1.06-3.38; P = 0.032). Further studies should be conducted to validate the prognostic value of HMGA2 for patients with GI cancers.

SMYD2-OE promotes oxaliplatin resistance in colon cancer through MDR1/P-glycoprotein via MEK/ERK/AP1 pathway

Background

SET and MYND domain-containing protein 2 (SMYD2-OE) plays an important role in cancer development through methylating histone and non-histone proteins. However, little is known about the relevance of SMYD2-OE in colon cancer. Moreover, oxaliplatin (L-OHP) is applied as first line for colon cancer chemotherapy, but drug resistance restricts its efficacy. Unexpectedly, the mechanism of L-OHP resistance in colon cancer remains unclear. In this study, we investigated the relationship of SMYD2-OE expression and L-OHP resistance in colon cancer and further explored the underlying mechanism linking SMYD2-OE, L-OHP resistance, and colon cancer.

Materials and methods

Expression levels of SMYD2-OE in colon cancer tissues of patients were tested. In vitro and in vivo assays were conducted to explore the function and mechanism of SMYD2-OE in colon cancer sensitivity to L-OHP.

Results

SMYD2-OE was overexpressed in colon cancer tissues compared with non-neoplastic tissues and associated with poor prognosis of patients with colon cancer after L-OHP-based chemotherapy. Knockdown of SMYD2-OE increased colon cancer sensitivity to L-OHP in vitro and in vivo. However, SMYD2-OE overexpression promoted L-OHP resistance in colon cancer cell in vitro. In addition, SMYD2-OE could upregulate MDR1/P-glycoprotein expression depending on MEK/ERK/AP-1 signaling pathway activity.

Conclusion

These results imply that SMYD2-OE promotes L-OHP resistance in colon cancer by regulating MDR1/P-glycoprotein through MEK/ERK/AP-1 signaling pathway, providing a potential strategy to sensitize chemotherapy by SMYD2-OE knockdown in colon cancer treatment.

Role of adenomatous polyposis coli (APC) gene mutations in the pathogenesis of colorectal cancer; current status and perspectives

Colorectal cancer (CRC) is one of the most common forms of solid tumors in the world with high rates of mortality and morbidity. Most cases of CRCs are initiated by inactivating mutations in a tumor suppressor gene, adenomatous polyposis coli (APC), leading to constitutive activation of the Wnt signaling pathway. This review summarizes the roles of somatic and germline mutations of the APC gene in hereditary as well as sporadic forms of CRC. We also discuss the diagnostic and prognostic value of the APC gene in the pathogenesis of CRC for a better understanding of CRC disease.

The 9p21 locus as a potential therapeutic target and prognostic marker in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related-death worldwide. Despite extensive efforts to identify valid biomarkers for the risk stratification of CRC patients, there are few of proven clinical utility. It is recognized that genetic factors play a major role in determining susceptibility to CRC. Recent genome-wide association studies have demonstrated common genetic variants in a region on chromosome 9p21 associated with an increased risk of CRC. Several genetic polymorphisms have been identified in this region that are associated with CRC. Three genes are located at this locus; CDKN2B(encoding-p15ink4b), CDKN2A (encoding-p16ink4a/p14ARF) and 3′ end of CDKN2BAS (termed-antisense-noncoding-RNA in the INK4-locus [ANRIL]). ANRIL has a post-transcriptional modulatory activity, which has been shown to perturb the expression of nearby genes. It also plays an important role in coordinating tissue remodeling through regulation of cell proliferation, apoptosis, aging, extra-cellular matrix remodeling and inflammatory response. However, the role of ANRIL is not well understood in CRC. Hypermethylation of the p14ARF and p16INK4a genes is often found in some tumors, including CRC. However, further studies are necessary to explore the clinical utility of these putative markers in risk stratification, and in the assessment of prognosis. In this review, we have summarized the prognostic and therapeutic potential of the p14ARF and p16INK4a genes in patients with colorectal cancer.

Toll like receptor signaling pathway as a potential therapeutic target in colorectal cancer

Toll like receptor (TLR) signaling is involved in activating innate and adaptive immune responses and plays a critical role in inflammation-induced diseases such as colorectal cancer (CRC). Dysregulation of this signaling pathway can result in disturbance of epithelial layer hemostasis, chronic inflammatory, excessive repair responses, and development of CRC. There is now substantial evidence for the benefit of targeting of this pathway in cancer treatment, and several agents have been approved, such as BCG (Bacillus Calmette Guérin), MPL (monophosphoryl lipid A) and imiquimod. This review summarizes the current knowledge about the different functions of TLRs on tumor cells and their application in cancer therapy with particular emphasis on recent preclinical and clinical research in treatment of CRC.