A negative-doughnut distal resection margin less than 5 mm does not affect prognosis in rectal cancer.

AIM: Many issues relating to the distal margin of anterior resection of the rectum still exist. We aimed to investigate whether negative distal resection margin (DRM) and positive DRM in the main specimen with negative doughnut has equivalent prognosis in patients with rectal cancer. METHODS: We included 287 patients with rectal cancer, including 69 cases with positive margins and 218 cases with negative margins, all of whom underwent regular follow-up. Survival rate was calculated using Kaplan-Meier survival analysis, while the log-rank test was used to determine statistical difference. Prognostic factors were found using the Cox regression model. RESULTS: There was no significant difference in clinicopathological features between the two groups with the exception of tumor location. Positive findings in the DRM with negative findings in the doughnut resection do not affect the overall survival, local recurrence, or distant metastasis. Factors relating to resection margin, such as the length of resection, negative, or positive findings, were not found to be prognostic. CONCLUSION: Given postoperative pathology results with positive DRM but negative findings in the doughnut resection, a second surgery was not necessary. Instead, adjuvant radiochemotherapy and close follow-up will suffice.

Very Early Colorectal Anastomotic Leakage within 5 Post-operative Days: a More Severe Subtype Needs Relaparatomy.

Early anastomotic leakage (AL), usually defined as leakage within 30 post-operative days, represents a severe entity. However, mounting evidence has indicated that majorities of leakage occur within one week after surgery, making late AL rarity. Here we analyzed 101 consecutive colorectal AL, all of which occurred within 30 post-operative days, during Jan 2013 and Dec 2015 in cancer hospital of Fudan University. AL occurring within 5 post-operative days was defined as very early AL (vE-AL). We evaluated risk factors of vE-AL compared with non-vEAL and correlated with post-leakage peritonitis and need of relaparatomy. We found that AL occurred at median time of 7 days after surgery. 23 cases were vE-AL. Reconstruction of post-peritoneum for mid-low rectal carcinoma significantly reduced incidence of vE-AL compared with non-vE-AL (p = 0.042). Patients with vE-AL was associated with presence of peritonitis (p = 0.031), the latter significantly correlated with increased re-operation rate (p = 6.8E-13). Besides, patients with vE-AL trended to correlate with increased re-operation rate after leakage (p = 0.088). In concludsion, vE-AL occurring within 5 post-operative days represents a severe subtype associated with general peritonitis and need of relaparatomy.

High expression of lncRNA MALAT1 suggests a biomarker of poor prognosis in colorectal cancer.

OBJECTIVE: This study sought to investigate the role of the long noncoding RNA MALAT1 in the prognosis of stage II/III colorectal cancer (CRC) patients. METHODS: The expression of MALAT1 was evaluated in cancer tissues from 146 stage II/III CRC patients undergoing radical resection and 23 paired normal colonic mucosa samples using quantitative real-time reverse transcriptase PCR. Differences in the expression of MALAT1 between 23 CRC and paired normal colonic mucosa samples were analysed with the Wilcoxon test. Relationships between the expression level of MALAT1, patient clinicopathological parameters and disease-free survival (DFS) and overall survival (OS) were analysed using the univariate Kaplan-Meier method and the multivariate COX regression model. RESULTS: The MALAT1 levels in cancerous tissues were 2.26 times higher than those measured in noncancerous tissues, and this difference was statistically significant (P = 0.0004). Based on their expression level of MALAT1, the patients were divided into a high MALAT1 expression group (n = 73) and a low expression group (n = 73). Patients with tumours harbouring higher expression of MALAT1 showed a significantly worse prognosis with a hazard ratio (HR) of 2.863 (95% CI, 1.659 to 4.943; P < 0.001) for DFS and 3.968 (95% CI, 1.665 to 9.456; P = 0.002) for OS. Furthermore, patients with perineural invasion demonstrated significantly worse DFS (HR = 3.459, 95% CI 2.008 to 5.957; P < 0.001) and OS (HR = 3.750, 95% CI 1.743 to 8.069; P = 0.001) than those without perineural invasion. Multivariate analyses indicated that MALAT1 expression and perineural invasion were two independent prognostic risk factors for patients with CRC. CONCLUSION: The expression of MALAT1 is upregulated in CRC tissues, and a higher expression level of MALAT1 might serve as a negative prognostic marker in stage II/III CRC patients.

Klotho suppresses growth and invasion of colon cancer cells through inhibition of IGF1R-mediated PI3K/AKT pathway.

Klotho (KL) was originally characterized as an aging suppressor gene, and has been identified as a tumor suppressor gene in a variety of cancers including colon cancer. However, the potential role and molecular events for KL in colon cancer remain unclear. The present study aimed to investigate the expression of KL in human colon cancer by immunohistochemistry, and to analyze the correlation between KL expression and clinicopathological characteristics of patients with colon cancer. Functional analysis after lentivirus-mediated gain of KL expression was used to assess the tumor growth and invasion in colon cancer cells in vitro and in vivo. The rate of KL expression was significantly decreased in cancer tissues compared with that in adjacent non-cancer tissues (ANCT) (60.3 vs.77.9%, P=0.022), and KL expression was negatively associated with Dukes staging (P=0.034) and depth of tumor invasion (P=0.008). Overexpression of KL in vitro inhibited cell proliferative activities and invasive potential in colon cancer cells, companied with decreased expression of p-IGF1R, p-PI3K, p-AKT, PCNA and MMP-2. In addition, the tumor volumes in the HT-29 subcutaneous tumor model treated with lentivirus­mediated KL vector (Lv-KL) was significantly smaller than those of the negative control (NC) group (P<0.01). Taken together, our findings indicate that the expression of KL is downregulated in human colon caner and correlates with tumor invasion and Dukes staging, while overexpression of KL suppresses growth and invasion through inhibition of IGF1R-mediated PI3K/AKT pathway in colon cancer cells, suggesting that KL may serve as a potential therapeutic target for the treatment of colon cancer.

RNA-seq reveals determinants for irinotecan sensitivity/resistance in colorectal cancer cell lines.

Irinotecan is a topoisomerase I inhibitor approved worldwide as a first- and second-line chemotherapy for advanced or recurrent colorectal cancer (CRC). Although irinotecan showed significant survival advantage for patients, a relatively low response rate and severe adverse effects demonstrated the urgent need for biomarkers searching to select the suitable patients who can benefit from irinotecan-based therapy and avoid the adverse effects. In present work, the irinotecan response (IC50 doses) of 20 CRC cell lines were correlated with the basal expression profiles investigated by RNA-seq to figure out genes responsible for irinotecan sensitivity/resistance. Genes negatively or positively correlated to irinotecan sensitivity were given after biocomputation, and 7 (CDC20, CTNNAL1, FZD7, CITED2, ABR, ARHGEF7, and RNMT) of them were validated in two CRC cell lines by quantitative real-time PCR, several of these 7 genes has been proposed to promote cancer cells proliferation and hence may confer CRC cells resistance to irinotecan. Our work might provide potential biomarkers and therapeutic targets for irinotecan sensitivity in CRC cells.

Silencing of CXCR7 gene represses growth and invasion and induces apoptosis in colorectal cancer through ERK and ß-arrestin pathways.

The CXC chemokine receptor 7 (CXCR7) has been reported to be involved in cell growth, metastasis and apoptosis in certain cancers. However, the function and molecular mechanisms of CXCR7 in human colorectal cancer (CRC) are still undefined. In the present study, sixty-eight cases of CRC tissues and corresponding adjacent non-cancer tissues (ANCT) were collected, and the expression of CXCR7 was assessed using immunohistochemistry (IHC) in biopsy samples. Furthermore, CXCR7 gene was silenced by small hairpin RNA-mediated lentiviral vector (Lv-shCXCR7), by transfection into human CRC cells (SW480 and HT-29). The levels of p-ERK, ß-arrestin, proliferating cell nuclear antigen (PCNA), matrix metallopeptidase-2 (MMP-2) and caspase-3 (CAS-3) were detected by western blotting. Cell proliferative activities and invasive capability were respectively measured by MTT and Transwell assays. Cell apoptosis was analyzed by flow cytometry. The results demonstrated that CXCR7 expression was significantly upregulated in CRC tissues compared with the ANCT (54.4 vs. 36.8%, P=0.041), and correlated with Dukes staging and depth of invasion (P=0.007; P=0.002). Silencing of CXCR7 gene suppressed cell proliferation and invasion, and induced cell apoptosis in CRC cells with decreased expression of p-ERK, ß-arrestin, PCNA and MMP-2 but increased expression of CAS-3. The tumor volumes in the SW480 subcutaneous tumor models treated with Lv-shCXCR7 were significantly smaller than those of the negative control (NC) and PBS groups (P<0.01). In conclusion, our findings indicate that upregulation of CXCR7 expression is associated with tumor invasion, and silencing of the CXCR7 gene represses the development of CRC cells through ERK and ß-arrestin pathways, suggesting that CXCR7 may serve as a potential therapeutic target for the treatment of CRC.

RNA-seq identifies determinants of oxaliplatin sensitivity in colorectal cancer cell lines.

Oxaliplatin-based chemotherapy, such as FOLFOX, is the first-line therapy for advanced colorectal cancer (CRC) or metastatic CRC patients. However, the partial response of patients to these regimes and the severe peripheral neuropathy toxicity induced by oxaliplatin makes it urgent to figure out biomarkers for oxaliplatin sensitivity to select suitable patients who benefit from these treatments. In present work, 21 CRC cell lines with different sensitivities to oxaliplatin were applied to RNA-seq. The basal expression profiles of these cell lines were correlated to their response to oxaliplatin. Bioinformatics analysis suggested that expression of 58 genes was correlated, negatively or positively, to oxaliplatin response across the 21 CRC cell lines. These 58 genes were mainly enriched in small molecules biochemistry, Wnt/ß-catenin signaling and EMT pathways. The latter two pathways were predicted to be activated in oxaliplatin-resistant CRC cell lines. Moreover, 15 genes were validated by qPCR that their expression levels were actually closely correlated to their response to oxaliplatin, in line with the biocomputation prediction. Taken together, our work might provide potential biomarkers for oxaliplatin sensitivity in CRC cell lines and therapeutic targets for combinational therapy with oxaliplatin.

Icariin-mediated inhibition of NF-κB activity enhances the in vitro and in vivo antitumour effect of 5-fluorouracil in colorectal cancer.

Colorectal cancer (CRC) is an aggressive malignancy that has a poor prognosis. 5-Fluorouracil (5-FU) is a first line chemotherapeutic medication used in the treatment of gallbladder cancer; however, the efficacy is below satisfactory. Icariin is a natural compound that is conventionally reported to have activity against a variety of cancers. This study was carried out to investigate the anti-cancer effect of icariin in CRC cells and to determine whether the compound can enhance the antitumour activity of 5-FU. Cell proliferation and apoptosis were measured using an MTT assay and flow cytometry, respectively. The activity of transcription factor NF-κB was determined by EMSA method. The expression of apoptosis- and proliferation-related proteins was determined by western blotting. The in vivo antitumour effect of combination treatment with icariin and 5-FU on CRC was also assessed using a murine model of CRC. Icariin sensitized the CRC cells to 5-FU both in vitro and in vivo. The antitumour activity of icariin and its potentiating effect on the antitumour activity of 5-FU implicated the suppression of NF-κB activity and consequent down-regulation of the gene products regulated by NF-κB. Our results showed that icariin, suppressed tumour growth and enhanced the antitumour activity of 5-FU in CRC by inhibiting NF-κB activity. Therefore, we suggest that combination of icariin with 5-FU might offer a therapeutic benefit to the patients with CRC; however, further studies are required to ascertain this proposition.