Guodong He

Silencing CDR1as inhibits colorectal cancer progression through regulating microRNA-7

An increasing number of studies have demonstrated that circular RNAs (circRNAs) can regulate gene expression through interacting with microRNAs. In this study, we analyzed the expression of antisense to CDR1as in colorectal cancer (CRC). CDR1as had a higher expression in CRC tissues compared to adjacent, normal mucosa and was positively associated with tumor size, T stage, lymph node metastasis, and poor overall survival (OS). Downregulation of CDR1as suppressed CRC cell proliferation and invasion and increased microRNA-7 (miR-7) expression. Intriguingly, ectopic expression of miR-7 in CRC cells consistently inhibited proliferation and invasion, and the miR-7 inhibitor was able to rescue the function of CDR1as knockdown. Mechanistic studies demonstrated that CDR1as silencing suppressed EGFR and IGF-1R expression, which could be partially blocked by the miR-7 inhibitor. Finally, positive correlations between CDR1as expression and EGFR and IGF-1R expression were observed in CRC samples. Thus, given the importance of CDR1as in blocking miR-7 and positively regulating EGFR and IGF-1R, dysregulated CDR1as expression may play an important role in CRC progression.

Immature Colon Carcinoma Transcript-1 (ICT1) Expression Correlates with Unfavorable Prognosis and Survival in Patients with Colorectal Cancer

BackgroundColorectal cancer (CRC) is the third leading cause of death from cancer worldwide. Immature colon carcinoma transcript-1 (ICT1) has been reported to be correlated with lung cancer; however, whether ICT1 is a functional gene in CRC, as well as the molecular mechanism underlying ICT1 mediation of colorectal-tumor formation, remains unknown.MethodsThe expression of ICT1 was firstly determined by using immunohistochemistry in 861 CRC specimens. The correlation of ICT1 expression with clinicopathological parameters and the survival rate was analyzed. Furthermore, we investigated the effect of ICT1 silencing on CRC cell proliferation and migration by MTT, colony formation, flow cytometry, and transwell in vitro.ResultsICT1 is highly expressed in a cohort of human CRCs, and that higher ICT1 expression may lead to reduced overall survival rate of CRC. Likewise, ICT1 silencing lowered the cell viability through cell-cycle arrest, inhibited cell migration, and induced apoptosis in CRC. We further revealed a novel mechanism in which ICT1 promoted CRC growth via the intracellular AMPK, SAPK/JNK, and PARP signaling pathways.ConclusionsOur data showed that ICT1 could be an important target for CRC diagnosis and treatment.

Ribosomal protein S15A promotes malignant transformation and predicts poor outcome in colorectal cancer through misregulation of p53 signaling pathway

Ribosomal protein S15A (RPS15A), which has been identified as a highly conserved 40S ribosomal protein, is essential for cell survival and proliferation. The present study evaluated the functional role of RPS15A in colorectal cancer (CRC), and our investigation found that RPS15A was highly expressed in a cohort of human CRC. High RPS15A expression was associated with older age (P=0.035), not receiving preoperative neoadjuvant treatment (P=0.048), higher primary pN stage (P=0.007) and slightly more synchronous distant metastases (P=0.058). The Cox univariate and multivariate hazard regression analysis revealed that higher expression of RPS15A led to a reduction of overall survival rate in CRC, indicating that enhanced RPS15A expression functions as an independent risk factor for the prognosis of CRC patients (P<0.001). Cell based analysis showed that RPS15A was widely expressed in human CRC cell lines. Knockdown of RPS15A significantly suppressed cell proliferation and colony formation in HCT116 and DLD-1 cells, and induced cell cycle arrest at G0/G1 phase. Genechip analysis suggested that knockdown of RPS15A might affect the p53 signaling pathway. Further study indicated that RPS15A knockdown upregulated p53 and p21 expression whereas downregulated CDK1 expression. In summary, the present study identified RPS15A as a novel univariate prognostic factor predicting a poor outcome in CRC patients. The RPS15A overexpression induced by malignant transformation of CRC might function through the p53 signaling pathway.

Silencing homeobox C6 inhibits colorectal cancer cell proliferation.

Homeobox C6 (HOXC6), a member of the homeobox family that encodes highly conserved transcription factors, plays a vital role in various carcinomas. In this study, we used a tissue microarray (TMA) consisting of 462 CRC samples to demonstrate that HOXC6 is more abundantly expressed in colorectal cancer (CRC) tissues than adjacent normal mucosa. Clinicopathological data indicated that higher HOXC6 expression correlated with poor overall survival and was associated with primary tumor location in the right colon, primary tumor (pT) stage 3/4 and primary node (pN) stage 1/2. Multivariate analysis showed that high HOXC6 expression was an independent risk factor for poor CRC patient prognosis. HOXC6 downregulation via lentivirus-mediated expression of HOXC6-targeting shRNA reduced HCT116 cell viability and colony formation in vitro, and reduced growth of subcutaneous xenografts in nude mouse. HOXC6 thus appears to promote CRC cell proliferation and tumorigenesis through autophagy inhibition and mTOR pathway activation.

Additional Biomarkers beyond RAS That Impact the Efficacy of Cetuximab plus Chemotherapy in mCRC: A Retrospective Biomarker Analysis

Purpose We aimed to identify new predictive biomarkers for cetuximab in first-line treatment for patients with RAS wild-type metastatic colorectal cancer (mCRC). Methods The study included patients with KRAS wild-type unresectable liver-limited mCRC treated with chemotherapy with or without cetuximab. Next-generation sequencing was done for single nucleotide polymorphism according to custom panel. Potential predictive biomarkers were identified and integrated into a predictive model within a training cohort. The model was validated in a validation cohort. Results Thirty-one of 247(12.6%) patients harbored RAS mutations. In training cohort (N=93), six potential predictive genes, namely, ATP6V1B1, CUL9, ERBB2, LY6G6D, PTCH1, and RBMXL3, were identified. According to predictive model, patients were divided into responsive group (n=66) or refractory group (n=27). In responsive group, efficacy outcomes were significantly improved by addition of cetuximab to chemotherapy. In refractory group, no benefit was observed. Interaction test was significant across all endpoints. In validation cohort (N=123), similar results were also observed. Conclusions In the first-line treatment of mCRC, the predictive model integrating six new predictive mutations divided patients well, indicating a promising approach to further refine patient selection for cetuximab on the basis of RAS mutations.

Low tumor infiltrating mast cell density confers prognostic benefit and reflects immunoactivation in colorectal cancer: Tumor infiltrating mast cell in colorectal cancer

The role of mast cells (MCs) in colorectal cancer (CRC) progression was controversial. Thus, our study was designed to evaluate the prognostic value of MCs as well as their correlation with immune microenvironment. A retrospective cohort of CRC patients of stages I–IV was enrolled in our study. Consecutive patients (854) were divided into training set (427 patients) and validation set (427 patients) randomly. The findings were further validated in a GEO cohort, GSE39582 (556 patients). The mast cell density (MCD) was measured by immunohistochemical staining of tryptase or by CIBERSORT algorithm. Low MCD predicted prolonged overall survival (OS) in training and validation set. Moreover, MCD was identified as an independent prognostic indicator in both sets. Better stratification for CRC prognosis can be achieved by building a MCD based nomogram. The prognostic role of MCD was further validated in GSE39582. In addition, MCD predicted improved survival in stages II and III CRC patients receiving adjuvant chemotherapy (ACT). Multiple immune pathways were enriched in low MCD group while cytokines/chemokines promoting anti‐tumor immunity were highly expressed in such group. Furthermore, MCD was negatively correlated with CD8+ T cells infiltration. In conclusion, MCD was identified as an independent prognostic factor, as well as a potential biomarker for ACT benefit in stages II and III CRC. Better stratification of CRC prognosis could be achieved by building a MCD based nomogram. Moreover, immunoactivation in low MCD tumors may contributed to improved prognosis.

Differences in clinical characteristics and mutational pattern between synchronous and metachronous colorectal liver metastases

Purpose To investigate differences in clinical characteristics and mutational patterns between synchronous and metachronous colorectal liver metastases (CLMs). Patients and methods From June 2008 to December 2014, patients with RAS wild-type CLMs treated at Zhongshan Hospital, Fudan University were included. DNA extracted from formalin-fixed paraffin-embedded tissue of primary tumors was sequenced with next-generation sequencing for single-nucleotide polymorphism of 96 genes according to custom panel. Mutations were compared between synchronous and metachronous liver metastases and correlated with clinical characteristics. Results A total of 161 patients were included: 93 patients with synchronous CLM and 68 patients with metachronous CLM. Patients with metachronous CLM were obviously elder. For pathology of primary tumors, synchronous CLMs were larger in size, poorly differentiated, and more frequently local advanced and lymph node positive. For evaluation of liver metastases, synchronous CLM had more and larger metastatic lesions. The median number of mutations in synchronous CLMs was significantly higher than in metachronous group (22 vs. 18, p<0.001). EGFR rs2227983 is the most prevalent mutation in both groups and only a part of prevalent mutations is shared in both groups. Prevalent mutations were correlated with many clinical characteristics. EGFR rs2227983, RBMXL3 rs12399211, and PTCH1 rs357564 were prognostic for latency of metachronous CLM. Conclusion Clinically, synchronous CLMs, compared with metachronous CLMs, were younger and showed heavier tumor burden for both primaries and liver metastases. Genetically, we identified different mutational patterns between synchronous and metachronous CLMs and several correlations between mutations and clinical characteristics. Further researches were needed to confirm these potential key mutations of CLMs.