Colorectal cancer in Chinese patients: current and emerging treatment options

Clinical presentation, treatment patterns, and outcomes of colorectal cancer patients at Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia: A prospective cohort study

BACKGROUND

Colorectal cancer (CRC) is the third most common cause of cancer death in both genders worldwide.

AIMS

This study aimed to evaluate the outcomes and prognostic factors of CRC patients at Tikur Anbessa Specialized Hospital in Ethiopia.

METHODS AND RESULTS

A prospective cohort study was conducted on 209 patients from January 2020 to September 2022. Kaplan-Meier curves and bivariate and multivariate Cox regression analyses were used to analyze overall and progression-free survival, with a significance value of P < .05. Results showed an overall mortality rate was 67.46% (95% confidence interval [CI]: 61.0-74.0), while the 1-year overall survival (OS) rate was 63.16% (95% CI: 56.23-69.29), with a median follow-up duration of 20 months. The median OS and progression-free survival times were 17 and 11 months, respectively. Age above 40 years (hazard ratio [HR] = 1.53, 1.02-2.29, p < .040), lower educational level (high school and below) (HR = 2.20, 1.24-3.90, p < .007), poor performance status (HR = 1.60, 1.03-2.48, p < .035), Hgb ≤12.5 g/dL (HR = 1.55, 1.03-2.08, p < .035), T-4 disease (HR = 6.05, 2.28-16.02, p < .000), and metastases at diagnosis (HR = 8.53, 3.77-19.25, p < .000) were all associated with poorer survival.

CONCLUSION

These findings suggest that poor survival of CRC patients in Ethiopia is largely due to advanced stage of the disease and lack of timely treatment, and highlight the urgent need for improved access to cancer treatment in the region.

Hypoxia-induced miR-653 enhances colorectal cancer progression by targeting circSETD3/KLF6 axis

The present work focused on exploring the role and underlying molecular mechanism of action of the non-coding RNA (miRNA/circRNA) in colorectal cancer (CRC). Here, we found that miR-653 was dramatically upregulated in CRC tissues and cells. CRC Patients with high miR-653 level possessed poor prognosis. miR-653 elevated proliferation, migration, and invasion, meanwhile suppressed apoptosis of CRC cells. Furthermore, circSETD3 directly sponged miR-653 and negatively regulate miR-653 to affect proliferation, migration, invasion, and apoptosis of CRC cells. Moreover, miR-653 served as carcinoma-promoting gene via targeting KLF6, and circSETD3 knockdown significantly reversed the inhibitory effect of KLF6 overexpression on CRC cells. In addition, hypoxia obviously increased expression of miR-653. Knockdown of miR-653 decreased the effects of hypoxia on CRC cell proliferation, migration and invasion. Taken together, these findings indicated that circSETD3/miR-653/KLF6 axis may be an effective therapeutic target for CRC patients.

Inhibition of CDK1 Reverses the Resistance of 5-Fu in Colorectal Cancer

Introduction

Although the survival rate of colorectal cancer (CRC) patients can be improved by surgery, radiotherapy, and chemotherapy, the resistance to 5-fluorouracil (5-Fu) affects the effect of chemotherapy and the prognosis of patients. An increasing number of studies showed that 5-Fu resistance was the main reason for the failure of colorectal cancer treatment. The poor prognosis of colorectal cancer greatly harms people’s health. This study aimed to clarify the correlation between cyclin-dependent kinase 1 (CDK1) and 5-Fu-induced tumor resistance.

Materials and Methods

Cell proliferation and invasion experiments showed that down-regulation of CDK1 inhibited fluorouracil-resistant CRC cell proliferation. The expression level of CDK1 was detected in 5-Fu-resistant CRC cells in vitro. Tumor growth was inhibited by down-regulation of CDK1 in tumor xenograft mouse models.

Results

We found that CDK1 was highly expressed in tumor tissues, especially in fluorouracil-resistant tissues. We also confirmed that the differential expression of 5-Fu in tumor tissues was related to tumor site, lymph node metastasis and stage. CDK1 promoted migration, invasion and inhibited apoptosis in 5-Fu-resistant CRC cells. Down-regulation of CDK1 inhibited fluorouracil-resistant CRC cell proliferation and tumorigenesis in vivo.

Conclusion

High expression of CDK1 may lead to poor clinical prognosis, and inhibition of CDK1 enhances 5-Fu sensitivity in CRC. Our research suggested that CDK1 may be used to predict 5-Fu efficacy and as a therapeutic target for CRC.

ERCC overexpression associated with a poor response of cT4b colorectal cancer with FOLFOX-based neoadjuvant concurrent chemoradiation

Colorectal cancer (CRC) of the clinical tumor stage T4b (cT4b) refers to advanced tumors with direct invasion of adjacent structures and the tumors are considered unresectable. Despite advancements in aggressive surgery and combination chemotherapy, the prognosis of cT4b CRC remains poor. Optimizing the therapeutic sequence administered to patients with cT4b CRC to improve clinical outcomes is crucial. In the present study, patients with unresectable cT4b and nodal stage N1-2 CRC were investigated at a single institution. A total of 20 consecutive patients were treated with pre-operative concurrent chemoradiation by using 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) since February 2015 and were regularly followed up until March 2020. Due to their poor response to concurrent chemoradiation (CCRT) with FOLFOX, the chemotherapy regimen was changed to irinotecan plus 5-fluorouracil/leucovorin (FOLFIRI) as the second-line neoadjuvant treatment. Genetic alterations, such as microsatellite instability (MSI), were documented, and the expression levels of excision repair cross-complementing group 1 (ERCC1) and ERCC2 were examined. Of the 20 patients, the tumors of 14 patients (70%) became resectable after FOLFIRI administration. The median duration between the last date of radiotherapy and surgery was 32.7 weeks (range, 10.1–59.3 weeks). Of note, 4 of the 14 patients with resectable tumors (28.6%) achieved a pathologic complete response. The median overall survival and progression-free survival were 27.5 months (range, 12–39 months) and 27.5 months (range, 8–39 months), respectively. The cancerous specimens of all of the patients (100%) exhibited ERCC2 overexpression and 18 specimens (90%) had ERCC1 overexpression. Only one tumor (5%) exhibited high MSI. The present study indicated that ERCC overexpression associated with the poor response of FOLFOX-based CCRT and FOLFIRI after FOLFOX-based CCRT failure may have a potential role in conversion to resectable tumors by neoadjuvant treatment in cT4b CRC. However, a further prospective study with more patients is required to improve the precision of the conclusions.

Paeonol exerts anti‑tumor activity against colorectal cancer cells by inducing G0/G1 phase arrest and cell apoptosis via inhibiting the Wnt/β‑catenin signaling pathway

Paeonol is a simple phenolic compound isolated from herbal root bark, which has been reported to possess numerous biological and pharmacological characteristics, including a desirable anti‑tumor effect. To date, the effect of paeonol against colorectal cancer (CRC) cells is yet to be fully elucidated. Therefore, the present study aimed to identify the underlying mechanism via which paeonol exerts its anti‑tumor activity on HCT116 cells. After incubation with various concentrations of paeonol (7.8125, 15.625, 31.25, 62.5, 125, 250 and 500 µg/ml), the inhibitory effect of paeonol on cell viability was assessed using a Cell Counting Kit‑8 assay. Cell apoptosis and cell cycle distribution were measured using flow cytometry. Moreover, caspase activity was measured using a colorimetric caspase assay. Luciferase assay was also used to determine the β‑catenin‑mediated transcriptional activity of T‑cell specific transcription factor/lymphoid‑enhancer binding factor (TCF/LEF), and western blotting analysis was performed to measure the related expression of proteins. The results indicated that paeonol exhibited a notable effect against HCT116 cells by inducing G0/G1‑phase arrest, as demonstrated by downregulation of the cell cycle regulators cyclin‑dependent kinase 4 and cyclin D1 and upregulation of p21Cip1 in a dose‑dependent manner. Furthermore, paeonol dose‑dependently induced cell apoptosis, accompanied by an increase in the Bax/Bcl‑2 ratio, release of cytochrome c and further activation of caspases. Paeonol also dose‑dependently blocked the activation of the Wnt/β‑catenin signaling pathway by suppressing the expression of β‑catenin, resulting in a decrease in β‑catenin‑mediated activity of TCF/LEF and downregulation of downstream target genes, including cyclin D1, survivin and c‑Myc. Therefore, the present results suggested that paeonol exerted its anti‑tumor effects on CRC cells, including the inhibition of cell proliferation, induction of cell cycle arrest and initiation of apoptosis, at least partly by suppressing the Wnt/β‑catenin pathway, which may offer a promising therapeutic strategy for CRC.

Meta-analysis of safety and efficacy of antiangiogenic drug aflibercept for metastatic colorectal cancer

BACKGROUND

Numerous studies have reported that the combination of arbacicept and FOLFOX4/FOLFIRI regimen can more effectively treat metastatic colon cancer (mCRC). In the preset study, we performed a meta-analysis to assess the efficacy and safety of arbacicept for mCRC to provide an evidence-based medicine related basis for the application of this drug.

AIM

To systematically assess the clinical efficacy and safety of aflibercept for patients with metastatic colorectal cancer (mCRC) by meta-analysis.

METHODS

Controlled trials that involved aflibercept with FOLFOX4/FOLFIRI regimen for treating mCRC from January 2009 to January 2019 were searched, covering China HowNet database, Weipu database, Wanfang database, China Biomedical Literature database, PubMed, as well as The Cochrane Library and EMBASE. The retrieved studies were evaluated according to the Cochrane Systematic Evaluation Manual. A meta-analysis was performed with RevMan5.3 software and 95% confidence interval (CI) estimation.

RESULTS

Five studies were included. The results of the meta-analysis showed that the 3-year overall survival rate and 3-year recurrence-free survival rate were significantly higher in the study group than in the control group (OR [odds ratio] = 0.52, 95%CI: 0.35-0.79, P = 0.002; OR = 0.63, 95%CI: 0.45-0.89, P = 0.008). Compared with the control group, the study group had fewer adverse events (OR = 0.58, 95%CI: 0.40-0.84, P = 0.004). Furthermore, the study group had a significantly lower incidence of diarrhea, leukopenia, loss of appetite, and nausea and vomiting than the control group (P < 0.05).

CONCLUSION

Aflibercept with FOLFOX4/FOLFIRI regimen has better efficacy and adverse event profile for treatment of refractory mCRC than FOLFOX4/FOLFIRI alone.

Knockdown Of TRIM31 Enhances Colorectal Cancer Radiosensitivity By Inducing DNA Damage And Activating Apoptosis

Purpose

Biomarkers that predict radiosensitivity are essential for personalized radiotherapy. We performed microarray analysis for rectal cancer patients between those with good response and poor response to preoperative radiotherapy and found that patients with lower expression of tripartite motif-containing protein 31 (TRIM31) showed a better response. In this study, we confirmed the effects of TRIM31 on radiosensitivity by knockdown of TRIM31 in colorectal cancer cells.

Methods and materials

Human colorectal cancer cell lines HT-29 and SW480, which are TRIM31 stably knocked-down, were used for analysis. We studied the level of DNA damage and the change of relative proteins after irradiation in TRIM31-knockdown cells. Flow cytometry was used to test for apoptosis, cell cycle stage, and reactive oxygen species (ROS) levels after irradiation. Cell survival was measured by cloning assay. Proteins related to DNA damage were evaluated by Western blotting.

Results

The percentage of apoptotic cells and the levels of ROS were elevated, and the survival fraction was reduced in TRIM31-knockdown cells. The expression levels of the DNA damage proteins phosphorylated ataxia-telangiectasia mutation (P-ATM), DNA protein kinases (DNA-PKs), and γ-H2AX were higher in TRIM31-knockdown cells.

Conclusion

Knockdown of TRIM31 increases DNA damage and radiosensitivity in colorectal cancer cells.

Ubiquitin-specific peptidase 22 promotes proliferation and metastasis in human colon cancer

Colon cancer is one of the most common malignant tumors in the world; however, the mechanism underlying the progression of colon cancer remains unclear. In the present study, the expression of ubiquitin-specific peptidase 22 (USP22) in paraffin sections of human colon cancer tissues and normal colon tissues were examined using immunohistochemistry. The human colon cancer cell lines HCT116 and HT29 were used for USP22 knockdown experiments, and functional assays were performed. The results demonstrated that compared with normal colon tissues, human colon cancer tissues exhibited upregulated expression of USP22 and this was associated with tumor lymph node metastasis and tumor stage in colon cancer tissues. In addition, upregulated expression of USP22 was significantly correlated with both lower relapse-free survival and lower overall survival rates in patients with colon cancer. When USP22 was silenced in colon cancer cell lines, this resulted in a decrease in cell proliferation and metastatic behaviors. Furthermore, Bmi-1 and Cyclin D2 were found to be positively regulated by USP22, which may have mediated the tumorigenic effects of USP22 in human colon cancer. The results of the present study may have significant implications for examining the underlying mechanisms of cancer development and the potential development of cancer therapeutics.

Molecularly annotation of mouse avatar models derived from patients with colorectal cancer liver metastasis

Background: Liver is the most common metastatic site in advanced colorectal cancer. Most patients with colorectal cancer liver metastasis (CRLM) do not benefit from current treatment. Patient-derived xenografts (PDXs) with defined molecular signatures are attractive models for preclinical studies. Methods: Successfully established PDXs were evaluated to elucidate their fidelity of patients' biologic characteristics (pathologic, genetic and protein properties, together with chemosensitivity). The genomic variations of PDXs were analyzed by next-generation sequencing to explore the underlying molecular mechanism of metastasis and potential therapeutic targets. Results: CRLM (N=73) showed a significantly higher successful PDX establishment rate than primary specimens (N=26; 76.7% vs. 57.7%). CRLM PDXs recapitulated the pathologic, genetic and protein properties of parental tumors, as well as chemosensitivity. Frequent altered genes in PDXs showed high consistency compared to patients' genomic alterations and were enriched in MAPK, ErbB, cell cycle, focal adhesion pathways for CRLM PDXs, whereas primary tumor-derived PDXs only exhibited genomic variations involving ErbB and cell cycle. The genetic alterations showed high concordance between paired PDXs from primary and metastatic tissues, except for recurrent gene mutations (ARID1A, CDK8, ETV1, STAT5B and WNK3) and common copy number gains in chromosomes 20q (e.g., SRC/AURKA). Several potential drug targets such as KRAS, HER2, and FGFR2 were validated using corresponding inhibitors. Additionally, PDX models could also be used in screening efficient regimens for patients with no druggable alterations. Conclusion: This study has successfully established and validated a large panel of molecularly annotated platforms from patients with CRLM for preclinical studies.

Clinical development of targeted and immune based anti-cancer therapies

Cancer is currently the second leading cause of death globally and is expected to be responsible for approximately 9.6 million deaths in 2018. With an unprecedented understanding of the molecular pathways that drive the development and progression of human cancers, novel targeted therapies have become an exciting new development for anti-cancer medicine. These targeted therapies, also known as biologic therapies, have become a major modality of medical treatment, by acting to block the growth of cancer cells by specifically targeting molecules required for cell growth and tumorigenesis. Due to their specificity, these new therapies are expected to have better efficacy and limited adverse side effects when compared with other treatment options, including hormonal and cytotoxic therapies. In this review, we explore the clinical development, successes and challenges facing targeted anti-cancer therapies, including both small molecule inhibitors and antibody targeted therapies. Herein, we introduce targeted therapies to epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), anaplastic lymphoma kinase (ALK), BRAF, and the inhibitors of the T-cell mediated immune response, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein-1 (PD-1)/ PD-1 ligand (PD-1 L).

PAR2 Inhibition Enhanced the Sensitivity of Colorectal Cancer Cells to 5-FU and Reduced EMT Signaling

The aim of this study was to investigate the underlying mechanisms that transforming growth factor-β (TGF-β)-mediated epithelial-to-mesenchymal transition (EMT) in tumor cells contributes to 5-FU resistance. A series of experiments involving cell viability and caspase activity analyses, siRNA transfection, RNA isolation, and quantitative-PCR (qPCR) assay, cell migration analysis, Western blotting analysis of total protein and membrane protein were performed in this study. Mouse xenograft model was used to determine the effect of the PAR2 inhibitor in vivo. In this study, we found that protease-activated receptor 2 (PAR2) induction in 5-FU therapy is correlated with TGF-β-mediated EMT and apoptosis resistance. PAR2 and TGF-β were both activated in response to 5-FU treatment in vivo and in vitro, and whereas TGF-β inhibition sensitized CRC cells to 5-FU and suppressed cell migration, PAR2 activation eliminated the effect of TGF-β inhibition. Conversely, siRNA-mediated PAR2 depletion or PAR2 inhibition with a specific inhibitor produced a similar phenotype as TGF-β signal inhibition: 5-FU sensitization and cell migration suppression. Moreover, the results of xenograft experiments indicated that the PAR2 inhibitor can enhance cell killing by 5-FU in vivo and suppress EMT signaling. Our results reveal that the TGF-β effects require the coordinating action of PAR2, suggesting that PAR2 inhibition could be a new therapeutic strategy to combat 5-FU resistance in CRC.

STK33/ERK2 signal pathway contribute the tumorigenesis of colorectal cancer HCT15 cells

Serine/threonine kinase 33 (STK33) is a serine/threonine kinase and participates in many apoptotic process. Herein, we found that the extracellular signal-regulated kinase 2 (ERK2) was a substrate of STK33. STK33 phosphorylated ERK2 and increased the activity of ERK2 and promote the tumorigenesis of colorectal cancer HCT15 cells. Clinical simple showed that STK33 was highly expression in colorectal cells and tissues. Ex vivo and in vivo studies demonstrated that STK33 accelerate tumorigenic properties in NCM460 cells and athymic nude rats. In vitro kinase assay results indicated that STK33 can phosphorylate ERK2. Ex vivo studies further showed that STK33 can bind with ERK2 and take part in the regulation of ERKs signaling pathway. In short, our results showed that STK33 is a novel upstream kinase of ERK2. It may provide a better prospect for STK33 based prevention and treatment for colorectal cancer patients.

MicroRNA-1296 Facilitates Proliferation, Migration And Invasion Of Colorectal Cancer Cells By Targeting SFPQ

MicroRNAs (miRNAs) are involved in cancer genesis and progression via acting as tumor suppressors or oncogenes. Previous studies report that miR-1296 shows upregulation in both colorectal cancer (CRC) tissues and plasma samples. However, the accurate clinical significance of miR-1296 and its role in CRC have not been well investigated. The aim of the present study was to disclose the aberrant expression, clinical significance, and the relevant biological function of miR-1296 in CRC. We found a marked upregulation of miR-1296 expression in CRC tissues compared to tumor-adjacent tissues. MiR-1296 overexpression was detected in five CRC cell lines (HCT116, Caco2, HT29, SW620 and SW480). High miR-1296 level was remarkably correlated with tumor size (>5cm), lymph node metastasis and TNM stage (III+IV). Notably. High miR-1296 expression was identified as a predictive factor for poor prognosis of CRC patients by survival analysis. MiR-1296 knockdown inhibited proliferation, migration, invasion capacities of HCT116 and SW480 cells in vitro. Moreover, miR-1296 silencing restrained the growth of CRC cells in vivo. Splicing factor proline and glutamine rich (SFPQ), a novel RNA binding protein, was identified as a direct target gene of miR-1296 in CRC. Downregulation of SFPQ expression was inversely associated with miR-1296 expression in CRC tissues. The Cancer Genome Atlas (TCGA) data revealed the prognostic value of dysregulated SFPQ in CRC patients. Interestingly, our findings established that the oncogenic role of miR-1296 was at least partially mediated by SFPQ in CRC cells. Collectively, these data indicate that miR-1296 accelerates CRC progression possibly by targeting SFPQ and may serve as a potential predictive factor and therapeutic target for CRC.

Overexpression of microRNA-15 increases the chemosensitivity of colon cancer cells to 5-fluorouracil and oxaliplatin by inhibiting the nuclear factor-κB signalling pathway and inducing apoptosis

Overcoming chemoresistance is a challenge in clinical treatment. It has been reported that microRNAs (miRNAs) are involved in regulating chemosensitivity. Therefore, the present study aimed to identify the effect and mechanism of miR-15 on colon cancer chemotherapy. Reverse transcription-quantitative polymerase chain reaction was performed to measure miR-15 level sin62-paired colon cancer and para-cancerous colon tissues. The overexpression of miR-15 in HCT116 cells was induced by transfection. The effect of miR-15 on the chemosensitivity of colon cancer cells to 5-fluorouracil (5-FU) and Oxaliplatin (OX) was determined using a luminescent cell viability assay. Flow cytometry, dual-luciferase assay and western blot analysis were used to determine the potential mechanism of miR-15. The results suggested that the expression of miR-15 was decreased in tumour tissues and that overexpression of miR-15 increased the chemosensitivity of colon cancer cells to 5-Fu and OX. miR-15 promoted apoptosis in colon cancer cells treated with 5-Fu and OX by inhibiting the expression of p50, which repressed the expression of B cell lymphoma-2 and B cell lymphoma-extra large; two direct target genes of nuclear factor-κB with anti-apoptotic functions. Thus, the current study demonstrated that miR-15 increased the chemosensitivity of colon cancer cells to 5-FU and OX by inhibiting the NF-κB signalling pathway and inducing apoptosis.

Role of serine/threonine kinase 33 methylation in colorectal cancer and its clinical significance

Serine/threonine kinase 33 (STK33) is a novel protein that has been the focus of an increasing number of studies in recent years; however, the role of STK33 in tumorigenesis remains controversial. Previous studies have demonstrated that STK33 is overexpressed in several human cancers and exerts a pro-tumorigenic effect through the promotion of cell proliferation. However, the role of STK33 in colorectal cancer (CRC), which is one of the most aggressive human malignancies, remains unclear. The aim of the current study was to investigate the methylation status of STK33 in CRC and to determine its clinical significance. The results demonstrated that STK33 was hypermethylated in CRC cell lines and promoted the proliferation of CRC cells. In addition, the methylation status and expression of STK33 in 94 pairs of cancer and noncancerous tissues obtained from patients with CRC was investigated. STK33 methylation was significantly increased in cancer tissues when compared with adjacent noncancerous tissues (P<0.001). STK33 methylation was associated with lymph node metastasis (P<0.05), tumor invasion (P<0.05), distant metastases (P<0.01) and tumor stage (P<0.01). Reduced STK33 mRNA and protein expression in CRC was associated with STK33 hypermethylation (P<0.001). In addition, patients with hypermethylated STK33 exhibited shorter overall survival rates when compared with those with unmethylated STK33 (P<0.01). In conclusion, the results of the current study suggest that STK33 hypermethylation may be a promising novel biomarker for the diagnosis, prognosis and suitable treatment of CRC.

Curcumin Suppresses the Colon Cancer Proliferation by Inhibiting Wnt/β-Catenin Pathways via miR-130a

Curcumin exhibits anti-tumor effects in several cancers, including colorectal carcinoma (CRC), but the detailed mechanisms are still unclear. Here we studied the mechanisms underlying the anti-tumor effect of curcumin in colon cancer cells. SW480 cells were injected into mice to establish the xenograft tumor model, followed by evaluation of survival rate with the treatment of curcumin. The expression levels of β-catenin, Axin and TCF4 were measured in the SW480 cells in the absence or presence of curcumin. Moreover, miRNAs related to the curcumin treatment were also detected in vitro. Curcumin could suppress the growth of colon cancer cells in the mouse model. This anti-tumor activity of curcumin was exerted by inhibiting cell proliferation rather than promoting cell apoptosis. Further study suggested that curcumin inhibited cell proliferation by suppressing the Wnt/β-catenin pathway. MiR-130a was down-regulated by curcumin treatment, and overexpressing miR-130a could abolish the anti-tumor activity of curcumin. Our study confirms that curcumin is able to inhibit colon cancer by suppressing the Wnt/β-catenin pathways via miR-130a. MiR-130a may serve as a new target of curcumin for CRC treatment.

The pattern of KRAS mutations in metastatic colorectal cancer: a retrospective audit from Sri Lanka

Objective

Activating mutations in the KRAS gene, found in approximately 53% of metastatic colorectal cancer (mCRC) cases, can render epidermal growth factor receptor (EGFR) inhibitors ineffective. Regional differences in these mutations have been reported. This is the first study which aims to describe the pattern of KRAS mutations in a Sri Lankan cohort of mCRC patients.

Results

The KRAS genotypes detected in mCRC patients which have been maintained in an anonymized database were retrospectively analyzed. Of the 108 colorectal tissue samples tested, 25 (23.0%) had KRAS mutations. Overall, there were 68 (63.0%) males and 40 (37.0%) females. Among the KRAS positive cases, there were 14 (56.0%) males and 11 (44.0%) females. Their age distribution ranged from 29 to 85 years with a median age of 61 years. There were 15 patients (60.0%) with point mutations in codon 12 while 10 (40.0%) had a single mutation in codon 13. The most common KRAS mutation identified was p.Gly13Asp (40.0%), followed by p.Gly12Val (24.0%). Other mutations included p.Gly12Cys (12.0%), p.Gly12Ser (12.0%), p.Gly12Asp (8.0%), and p.Gly12Arg (4.0%). The codon 13 mutation was a G>A transition (40.0%), while G>T transversions (32.0%), G>A transitions (24.0%), and G>C transversions (4.0%) were found in the codon 12 mutations. The frequency of KRAS mutations was similar to that reported for Asian patients. However, in contrast to several published studies, the G>A transition in codon 12 (c.35G>A; p.Gly12Asp), was not the most common mutation within codon 12 in our cohort. This may be a reflection of the genetic heterogeneity in the pattern of KRAS mutations in mCRC patients but valid conclusions cannot be drawn from these preliminary findings due to the small size of the study sample.

The role of MRP1 in the multidrug resistance of colorectal cancer

The role of multidrug resistance associated protein 1 (MRP1) in the multidrug resistance (MDR) of colorectal cancer (CRC) remains unclear. The present study aimed to investigate the effect of MRP1 in MDR CRC and its therapeutic potential for the treatment of patients with this disease. The human MDR CRC cell lines HCT-8 and Colo205 were established through stable exposure to 5-florouracil (5-FU) over a 5-month period. MRP1 was knocked-down in MDR CRC cells through the transfection of short hairpin RNA targeting MRP1 (shMRP1). Western blotting was performed to assess the efficiency of this silencing. MTT and apoptosis assays were conducted to detect cell viability and apoptosis, respectively. Compared with their parental cells, HCT-8/5-FU and Colo205/5-FU cells were 23.1 and 15.8 times more resistant to 5-FU, and 17.2 and 20.9 times more resistant oxaliplatin, respectively. The knockdown of MRP1 resulted in the attenuation of the MDR phenotype through the induction of apoptosis. The shMRP1-transfected Colo205/5-FU cells were injected subcutaneously into the right scapular region of BALB/c nude mice and tumor size was measured for 15 days post-injection. This in vivo experiment demonstrated that MRP1 knockdown inhibited tumor growth. On the 9, 12 and 15th day post-injection, tumor volume in the shMRP1-transfected Colo205/5-FU cell-injected group was significantly lower compared with that in the Colo205/5-FU cell-injected group (day 9, 2.1±0.8 vs. 6.9±1.9 mm³, P=0.009; day 12, 3.1±1.4 vs. 14.3±4.0 mm³, P=0.008; day 15, 4.8±2.7 vs. 21.3±3.4 mm³; all P<0.001). These results demonstrate that MRP1 serves a role in the MDR phenotype of CRC through inhibiting apoptosis and may serve as a potential therapeutic target for inhibition, which would increase the efficacy of other chemotherapeutic agents in the treatment of CRC.

Expression of inositol-requiring enzyme 1β is downregulated in colorectal cancer

The endoplasmic reticulum stress inositol-requiring enzyme (IRE) 1α/X-box binding protein (XBP) 1 signaling pathway is involved in the tumorigenesis of breast and prostate cancer. Mucin 2 (MUC2) protects colon tissues from the formation of tumors. In human colorectal cancer (CRC) the role of IRE1α, and its analogue, IRE1β, has yet to be elucidated. In the present study, the expression levels of IRE1α, IRE1β, un-spliced XBP1u, spliced XBP1s and MUC2 in surgically resected cancerous and adjacent non-cancerous tissues from patients with CRC were investigated. The IRE1α, IRE1β, XBP1u, XBP1s and MUC2 mRNA expression levels were determined using reverse transcription-quantitative polymerase chain reaction, and the protein expression levels were detected using immunohistochemistry and western blotting. The association between the expression levels of IRE1α, IRE1β and MUC2 and the clinicopathological features of patients with CRC was subsequently analyzed. The mRNA expression levels of IRE1β and MUC2 were decreased by ~2.1 and ~4.5-fold in CRC tissues, respectively, as compared with the adjacent normal tissues. The protein expression levels of IRE1β and MUC2 were decreased by ~8.0 and ~2.0-fold in the CRC tissues, respectively. IRE1β mRNA expression levels were positively correlated with MUC2 mRNA expression levels. IRE1β expression levels were revealed to be significantly associated with lymph node metastasis, tumor stage and histological differentiation. However, IRE1α, XBP1u and XBP1s mRNA and IRE1α protein expression levels were not observed to significantly differ between cancerous tissues and the adjacent normal tissues. The results indicated that the expression of IRE1β, but not IRE1α, may protect colon tissue from developing CRC by inducing MUC2 expression. Therefore, decreased IRE1β expression levels may be associated with the development of CRC through the inhibition of MUC2 expression.

Association between proto-oncogene mutations and clinicopathologic characteristics and overall survival in colorectal cancer in East Azerbaijan, Iran

Background

Colorectal cancer (CRC) is the third-most common cancer in Iran. The increasing incidence of CRC in the past three decades has made it a major public health burden in the country. This study aimed to determine any relationship of specific mutations in CRCs with clinicopathologic aspects and outcome of patients.

Materials and methods

This study was conducted on 100 CRC patients by the case-only method. Polymerase chain-reaction products were analyzed by Sanger sequencing, and sequence results were compared with the significant KRAS and BRAF gene mutations in the My Cancer Genome database. Logistic regression models were used to detect associations of clinicopathologic characteristics with each of the mutations. Kaplan–Meier and Cox regression models were constructed to estimate overall survival in patients.

Results

A total of 26 subjects (26%) had heterozygote-mutant KRAS, and mutations were not detected in the amplified exon of BRAF in both tumor and normal tissues of the 100 CRCs. Rectal tumors had 1.53-fold higher likelihood of KRAS mutations than colon tumors, and men had 1.37-fold higher odds than women. The presence of metastasis increased the likelihood of KRAS mutations 2.36-fold over those with nonmetastatic CRCs. Compared to patients with KRAS wild-type cancers, those with KRAS mutations had significantly higher mortality (hazard ratio 3.74, 95% confidence interval 1.44–9.68; log-rank P=0.003).

Conclusion

Better understanding of the causality of CRC can be established by combining epidemiology and research on molecular mechanisms of the disease.

EZH2 mediates lidamycin-induced cellular senescence through regulating p21 expression in human colon cancer cells

Lidamycin (LDM) is a novel member of the enediyne antibiotics identified in China with potent antitumor activity. However, it remains unclear whether LDM has potential molecular targets that may affect its antitumor activity. Enhancer of zeste homolog 2 (EZH2) functions as a histone lysine methyltransferase and mediates trimethylation on histone 3 lysine 27 (H3K27me3). High EZH2 level is found to be positively correlated with the aggressiveness, metastasis and poor prognosis of cancer. Here, we aim to study the role of EZH2 in LDM-induced senescence, as well as in the cytotoxicity of LDM in human colon cancer cells. LDM is found to be relatively more potent in inhibiting the colon cancer cells harboring high EZH2 level and induces irreversible cellular senescence at IC50 dose range, as evidenced by senescence-associated β-galactosidase staining, cell cycle arrest and molecular changes of senescence regulators including p21 in HCT116 and SW620 cells. More importantly, LDM is found to markedly inhibit EZH2 expression at both protein and mRNA levels upon the induction of p21 and cellular senescence. LDM also selectively inhibits EZH2 expression as compared with other histone lysine methyltransferases. Knockdown of p21 with siRNAs abolishes LDM-induced senescence, whereas EZH2 knockdown markedly increases p21 expression and causes senescent phenotype. Enrichment of both EZH2 and H3K27me3 levels in the p21 promoter region is reduced by LDM. Moreover, EZH2 overexpression reduces cellular senescence, p21 expression and DNA damage response upon LDM exposure. LDM also demonstrates potent antitumor efficacy in xenografted animal models. Collectively, our work provides first demonstration that EZH2 may mediate, at least partially, the senescence-inducing effects of LDM by regulating p21 expression and DNA damage effect. Thus, EZH2 may serve as a potential target and biomarker to indicate the clinical efficacy of the potent enediyne antitumor drug.

The clinical significance of forkhead box protein A1 and its role in colorectal cancer

Forkhead box protein A1 (FOXA1) is a transcription factor; recent studies have reported that FOXA1 has an oncogenic or tumor suppressive role in human malignancies, and its expression is associated with the prognosis of patients with cancer. However, further studies are required to determine the clinical significance of FOXA1 and its role in colorectal cancer (CRC). In the present study, FOXA1 expression was detected in 90 samples of CRC tissues and matched noncancerous tissues using immunohistochemistry. In these cases, FOXA1 expression was detected in 57.8% (52/90) of the CRC samples, whereas only 37.8% (34/90) of the noncancerous specimens exhibited a positive FOXA1 signal. In addition, the present study demonstrated that the mRNA expression levels of FOXA1 were significantly increased in CRC tissues compared with in matched tumor-adjacent tissues. Furthermore, the positive expression of FOXA1 was associated with poor clinicopathological characteristics of CRC, including poor tumor differentiation, large tumor size, lymph node metastases and advanced tumor-node-metastasis tumor stage. Notably, patients with CRC with positive FOXA1 expression exhibited a significantly reduced 5-year survival rate compared with those with negative FOXA1 expression. Multivariate Cox regression analysis revealed that FOXA1 expression was an independent prognostic indicator for patients with CRC. In addition, FOXA1 knockdown evidently inhibited cell proliferation and induced apoptosis in SW480 and HCT116 CRC cells. Notably, FOXA1 knockdown also prominently reduced the expression of yes-associated protein (YAP) in SW480 and HCT116 cells. In conclusion, the results of the present study indicated that FOXA1 may be considered a potential prognostic marker, and may promote tumor growth of CRC by upregulating YAP expression.

miR-517a is an independent prognostic marker and contributes to cell migration and invasion in human colorectal cancer

Colorectal cancer (CRC) is a highly invasive tumor that is frequently associated with distant metastasis, which is the primary cause of poor prognosis. However, the mechanisms of metastasis remain poorly understood. MicroRNAs (miRNAs/miRs) have been considered to be implicated in CRC progression. In particular, miR-517a is proposed as a novel tumor-associated miRNA and has a potential role in tumor metastasis. The expression of miR-517a in CRC specimens was detected by reverse transcription-quantitative polymerase chain reaction. Transwell assays were performed to determine the migration and invasion of CRC cells. The putative target genes of miR-517a were disclosed using publicly available databases and western blot analysis. The present study identified that the expression of miR-517a was significantly higher in CRC tissues as compared with adjacent non-tumor tissues. Clinical analysis indicated that increased expression of miR-517a was correlated with poor prognostic features and poor long-term survival of CRC patients. In vitro evidences demonstrated that downregulation of miR-517a inhibited cell migration and invasion in HCT-116 cells. By contrast, upregulation of miR-517a increased the number of migrated and invaded SW480 cells. Notably, miR-517a expression was inversely regulated by forkhead box J3 (FOXJ3) abundance in CRC cells. Furthermore, an inverse correlation between miR-517a and FOXJ3 expression was observed in CRC tissues. In conclusion, miR-517a appears to be an independent prognostic marker for predicting survival of CRC patients, and may promote cell migration and invasion by inhibiting FOXJ3.

Meta-analysis of efficacy and safety of capecitabine combined with radiotherapy in Chinese patients with advanced rectal cancer

AIM: To perform a systematic review of the clinical efficacy and safety of capecitabine combined with radiotherapy in advanced rectal cancer.

METHODS: MEDLINE, the China Biological Medicine Disc (CBM), the China National Knowledge Infrastructure (CNKI) and Wanfang databases were searched to retrieve studies evaluating the clinical efficacy and safety of capecitabine combined with radiotherapy in advanced rectal cancer. In accordance with evidence-based medicine (Cochrane) systematic overview methods, the quality of the included studies was assessed and valid data were extracted. Meta-analysis was performed using RevMan5.3 software.

RESULTS: Thirty-two trials involving 1876 patients were analyzed in this meta-analysis. The results of Meta-analysis showed that the experimental group had significantly higher overall response rate, radical resection rate, anus-saving rate, one- and two-year survival rates, as compared with the control group (P < 0.01). The anastomotic leakage rate and local recurrence (LR) rate after treatment in the experimental group were significantly lower than those in the control group (P < 0.01). Furthermore, the rates of adverse reactions were also higher in the experimental group than those in the control group. No difference in the remission rate of pain was found between the experimental and control groups (P > 0.01).

CONCLUSION: In Chinese patients with advanced rectal cancer, short-term efficacy and long-term survival rates associated with capecitabine combined with radiotherapy are significantly better than those with other therapies, but the combination therapy causes more adverse reactions. The remission rate of pain does not significantly differ in the two groups.

Inhibition of SALL4 suppresses carcinogenesis of colorectal cancer via regulating Gli1 expression

BACKGROUND

SALL4 is a novel oncogene mediating tumorigenesis in multiple carcinomas. However, its actual role and mechanisms participating in the development of colorectal cancer remains unclear.

METHODS

Immunohistochemical staining and Western blot were conducted to detect the expression of SALL4 and other molecules. siRNA of SALL4 was transfected to silence SALL4 expression in Caco-2 cell line. Flow cytometry was used for cell cycle and apoptosis analysis. Wound healing and transwell assay were used for invasion test. CCK-8 test was employed for cell proliferation and drug sensitivity assessment.

RESULTS

By inhibition of SALL4 expression, the proliferation, invasiveness and drug resistance were dramatically reduced while apoptosis rate was up-regulated. Gli1 was found to decrease its expression in SALL4 silencing cells. Moreover, the inhibition on tumorigenesis of Caco-2 by SALL4 silencing was antagonized by Gli1 up-regulation, suggesting Gli1 as a downstream target of SALL4 in cancer development.

CONCLUSION

SALL4 inhibition limited oncogenesis on colorectal cancer by reducing Gli1 expression.

DZNep inhibits the proliferation of colon cancer HCT116 cells by inducing senescence and apoptosis

EZH2 is over-expressed in human colon cancer and is closely associated with tumor proliferation, metastasis and poor prognosis. Targeting and inhibiting EZH2 may be an effective therapeutic strategy for colon cancer. 3-Deazaneplanocin A (DZNep), as an EZH2 inhibitor, can suppress cancer cell growth. However, the anti-cancer role of DZNep in colon cancer cells has been rarely studied. In this study, we demonstrate that DZNep can inhibit the growth and survival of colon cancer HCT116 cells by inducing cellular senescence and apoptosis. The study provides a novel view of anti-cancer mechanisms of DZNep in human colon cancer cells.