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MicroRNA-93 (miR-93) is involved in several carcinoma progressions. It has been reported that miR-93 acts as a promoter or suppressor in different tumors. However, till now, the role of miR-93 in colon cancer is unclear. Herein, we have found that expression of miR-93 was lower in human colon cancer tissue and colorectal carcinoma cell lines compared with normal colon mucosa. Forced expression of miR-93 in colon cancer cells inhibits colon cancer invasion, migration, and proliferation. Furthermore, miR-93 may downregulate the Wnt/β-catenin pathway, which was confirmed by measuring the expression level of the β-catenin, axin, c-Myc, and cyclin-D1 in this pathway. Mothers against decapentaplegic homolog 7 (Smad7), as an essential molecular protein for nuclear accumulation of β-catenin in the canonical Wnt signaling pathway, is predicted as a putative target gene of miR-93 by the silico method and demonstrated that it may be suppressed by targeting its 3'UTR. These findings showed that miR-93 suppresses colorectal cancer development via downregulating Wnt/β-catenin, at least in part, by targeting Smad7. This study revealed that miR-93 is an important negative regulator in colon cancer and suggested that miR-93 may serve as a novel therapeutic agent that offers benefits for colon cancer treatment.

Summary Hypoxia is serving crucial roles in cancers. This study aims to comprehensively analyze the molecular features and clinical relevance of a well-defined hypoxia-associated signature in pan-cancer using multi-omics data. Data were acquired from TCGA, CCLE, GDSC, and GEO. RNA expression pattern, copy number variation (CNV), methylation, and mutation of the signature were analyzed. The majority of the 15 genes were upregulated in cancer tissues compared with normal tissue, and RNA expression was negatively associated with methylation level. CNV occurred in almost all the cancers, whereas mutation frequency was low across different cancer types. The signature was also closely related to cancer hallmarks and cancer-related metabolism pathways. NDRG1 was upregulated in kidney cancer tissues as indicated by immunohistochemistry. Besides, most of the 15 genes were risk factors for patients' overall survival. Our results provide a valuable resource that will guide both mechanistic and therapeutic analyses of the hypoxia signature in cancers.

MicroRNAs (miRNAs) are deregulated in a number of cancers including colorectal cancer. MiR-30c belongs to miR-30 family, and is involved in a variety of malignant diseases. In this study, we detected the expression of miR-30c in colon cancer cell lines and clinical colon cancer specimens. MiR-30c was shown to be dramatically down-regulated both in cell lines and cancer tissues. Additionally, miR-30c could inhibit cancer cell growth, migration and invasion in vitro. Consistently, stable over-expression of miR-30c inhibited the growth and lung metastasis of colon cancer cell xenografts in vivo. Furthermore, bioinformatics algorithm and luciferase reporter assay indicated ADAM19 as a direct target of miR-30c. Of interest, further experiments demonstrated that inhibition of ADAM19 by miR-30c partially mediated the anti-tumor effect of miR-30c. Overall, our study provides the new insight that miR-30c inhibited colon cancer cells via targeting ADAM19. Thus, miR-30c might serve as a promising therapeutic strategy for colon cancer treatment.

d MicroRNAs (miRNAs) are dysregulated in many types of malignant diseases, including colorectal cancer. miRNA 30a (miR-30a) is a member of the miR-30 family and has been implicated in many types of cancers. In this study, we determined the expression of miR-30a in human colon cancer tissues and cell lines. miR-30a was found to be significantly downregulated in both the tissues and cell lines. Furthermore, overexpression of miR-30a inhibited, while silencing of miR-30a promoted, cell proliferation, migration, and invasion in vitro. Consistently, stable overexpression of miR-30a suppressed the growth of colon cancer cell xenografts in vivo. Moreover, bioinformatic algorithms and luciferase reporter assays revealed that insulin receptor substrate 2 (IRS2) is a direct target of miR-30a. Further functional studies suggested that repression of IRS2 by miR-30a partially mediated the tumor suppressor effect of miR-30a. In addition, miR-30a inhibited constitutive phosphorylation of Akt by targeting IRS2. Additionally, clinicopathological analysis indicated that miR-30a has an inverse correlation with the staging in patients with colon cancer. Taken together, our study provides the first evidence that miR-30a suppressed colon cancer cell growth through inhibition of IRS2. Thus, miR-30a might serve as a promising therapeutic strategy for colon cancer treatment. Colorectal cancer (CRC) is the third most common cancer in males and females, with an estimated 142,820 new cases and 50,830 deaths in the United States in 2013. The overall CRC incidence is 5% in the general population, and the 5-year survival rate ranges from 40% to 60% (1). Despite the improvement of currently available treatment strategies, including surgical resection, radiotherapy, and chemotherapy, the survival rate of patients with CRC has changed little over the past 10 years. Almost 50% of CRC patients will die of the disease, mainly due to metastasis to the liver. Thus, it is imperative to achieve earlier diagnosis and better tailoring of treatments to improve CRC outcomes.MicroRNAs (miRNAs) are a family of endogenous small noncoding RNAs that regulate gene expression via the sequence-specific base pairing on the 3= untranslated regions (3= UTRs) of target mRNAs, resulting in mRNA cleavage or translation inhibition (2). More than 30% of the protein-coding genes are controlled by miRNAs, as indicated by bioinformatics predictions. miRNAs are involved in a plethora of biological processes, such as proliferation, migration, invasion, and apoptosis (3, 4). In recent years, miRNAs have been recognized as critical regulators in development and progression of cancer, including CRC (5-8).miRNA 30a (miR-30a) is a member of the miR-30 family, which consists of six distinct mature miRNA sequences: miR-30a/ miR-30c-2, miR-30d/miR-30b, and miR-30e/miR-30c-1 (9). There is considerable evidence suggesting that the dysregulation of miR-30a is correlated with several types of malignant tumors, including breast cancer, lung cancer, thyroid cancer, gastric cancer, and leuke...

Colorectal cancer stem cells (Co-CSCs) are a small subpopulation of tumor cells which have been proposed to be tumor-initiating cells in colorectal cancer (CRC) and to be implicated in resistance to standard chemotherapy. Chemoresistance is a common problem in the clinic. However, the interrelation between Co-CSCs and chemoresistant cells has yet to be elucidated. The present study investigated the Co-CSC phenotype in colonospheres and chemoresistant CRC cell lines and aimed to identify targets for therapy. Colonospheres and chemoresistant CRC cells were found to be enriched with the CSC markers CD133 and CD44, and exhibited similar phenotypes. Furthermore, it was found that Notch signaling may simultaneously regulate Co-CSCs and chemoresistant cells and may represent a novel strategy for targeting this pathway in CRC.

To investigate the role of miR-450b-5p, a newly identified microRNA, located in the Xq26 region, in development of chemoresistance in colorectal cancer (CRC), and to explore the underlying mechanism by which miR-450b-5p regulates this process. In this study, we demonstrated that expression of miR-450b-5p was downregulated in recurrent CRC tissues. We found that expression of miR-450b-5p was significantly inhibited in response to 5-fluorouracil (5-FU) treatment in HT-29 cells and HCT-116 cells. Importantly, overexpression of miR-450b-5p in 5-FU-resistant HT-29 cells reduced cell viability, but elevated DNA fragmentation levels and caspase-3 activity were induced by treatment with 5-FU. Conversely, inhibition of miR-450b-5p enhanced resistance to 5-FU, and promoted cell viability in HCT-116 cells. Mechanistically, we found that miR-450b-5p directly targeted SOX2, an essential factor in stem cells. Expression of miR-450b-5p was negatively correlated to the expression of SOX2, the percentages of CD133(+) cells present, and sphere-forming capacity in CRC cells. Finally, depletion of SOX2 abolished the effects of suppression of miR-450b-5p on stemness and chemoresistance in HT29 cells. We have demonstrated that miR-450b-5p inhibits stemness and development of chemoresistance to 5-FU in CRC cells. These results indicate that miR-450b-5p may be a key determinant of 5-FU sensitivity, and may represent a novel therapeutic target to facilitate chemotherapy for CRC.