RESUMO
Dysregulation of SUMO-specific protease 1 (SENP1) expression has been reported in several kinds of cancer, including human colorectal and prostate cancers, proposing SENP1 as an oncogene with a critical role in cancer progression. miR-133a-3p has been reported as a tumor suppressor in several malignant neoplasias. However, the precise molecular mechanisms underlying its role in colorectal cancer remain largely unknown. The aim of this work was to investigate the relationship between miR-133a-3p and SENP1 in colorectal cancer cells. We found that miR-133a-3p expression was downregulated in colorectal cancer tissues. In silico analyses indicated that SENP1 is one of the target genes of miR-133a-3p. Overexpression of miR-133a-3p mimics was able to inhibit cell growth with G1 arrest of colorectal cancer cells. Overexpression of miR-133a-3p antisense promoted cell growth of colorectal cancer cells. The luciferase reporter experiments showed that miR-133a-3p regulated the expression of SENP1 by combining with its 3'-UTR and resulted in downregulation of SENP1 and upregulation of CDK inhibitors such as p16, p19, p21, and p27. These results suggest that the miR-133a-3p-SENP1 axis might play a role in cell proliferation and cell cycle regulation of colorectal cancer cells.
Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Cisteína Endopeptidases/biossíntese , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/genética , Ciclo Celular/genética , Proliferação de Células/genética , Cisteína Endopeptidases/genética , HumanosRESUMO
Epigenetic changes have been recently recognized as important in many human cancers. Enhancer of zeste homologue 2 (EZH2)gene has shown overexpression in various human cancers, consistent with a straightforward role of EZH2 as an oncogene, but its function in carcinogenesis is partly contradictory. The role of EZH2 in development of human colorectal cancer (CRC) has not yet been clarified. In present study, we observed up-regulation of EZH2 expression in tumor tissues from CRC patients [corrected]. The expression of EZH2 in CRC cell lines is consistent with the trend in cancer tissues using RT-PCR. We showed that TNM stage and lymph node metastasis in CRC patients are significantly correlated with EZH2 expression levels [corrected]. EZH2 level of transcription and protein was inhibited by small interfering RNA (siRNA). More importantly, EZH2-siRNA inhibited the proliferation and migration of SW620 cells while promoting their apoptosis, and inducing G0/G1 cell cycle arrest of CRC cells. Collectively, our results suggest that upregulated EZH2 expression may contribute to the progression of the patients with CRC. A comprehensive study of epigenetic mechanisms and the relevance of EZH2 in CRC is important for fully understanding this disease and as a basis for developing new treatment options in patients with CRC [corrected].