miRNA-331-3p directly targets E2F1 and induces growth arrest in human gastric cancer
ABSTRACT Deregulation of E2F1 activity is characteristic of gastric tumorigenesis, which involves in complex molecular mechanisms. microRNA is one of the post-transcriptional regulators for gene expression. Here, we report a member of miR-331 family, miR-331-3p, which was decreased in some kinds of malignancies. However, the biological function of miR-331-3p on gastric cancer is largely unknown. In this study, we screened the expressing levels of miR-331-3p and E2F1 in gastric cancer cell lines. We transfected precursor or inhibitor of miR-331-3p into gastric cancer cells. As results, miR-331-3p is down-regulated in all gastric cancer cell lines by real-time PCR. Over-expression of miR-331-3p blocked G1/S transition on SGC-7901 and AGS cell lines. Introduction of miR-331-3p dramatically suppressed the ability of colony formation and cell growth in vitro by interfering E2F1 activity. Our data highlight an important role of miR-331-3p in cell cycle control by targeting 3'-UTR of cell cycle-related molecule E2F1. We concluded that miR-331-3p is a potential tumor suppressor in gastric cancer. Restoring miR-331-3p in gastric cancer cells revealed potential application in gastric cancer therapy.
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ABSTRACT: The lignan arctigenin (ARG) from the herb Arctium lappa L. possesses anti-cancer activity, however the mechanism of action of ARG has been found to vary among tissues and types of cancer cells. The current study aims to gain insight into the ARG mediated mechanism of action involved in inhibiting proliferation and inducing apoptosis in lung adenocarcinoma cells. This study also delineates the cancer cell specificity of ARG by comparison with its effects on various normal cell lines. ARG selectively arrested the proliferation of cancer cells at the G0/G1 phase through the down-regulation of NPAT protein expression. This down-regulation occurred via the suppression of either cyclin E/CDK2 or cyclin H/CDK7, while apoptosis was induced through the modulation of the Akt-1-related signaling pathway. Furthermore, a GSH synthase inhibitor specifically enhanced the cytotoxicity of ARG against cancer cells, suggesting that the intracellular GSH content was another factor influencing the susceptibility of cancer cells to ARG. These findings suggest that specific cytotoxicity of ARG against lung cancer cells was explained by its selective modulation of the expression of NPAT, which is involved in histone biosynthesis. The cytotoxicity of ARG appeared to be dependent on the intracellular GSH level.Phytomedicine: international journal of phytotherapy and phytopharmacology 09/2013; 21(1). DOI:10.1016/j.phymed.2013.08.003 · 2.88 Impact Factor
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ABSTRACT: Purpose: MicroRNAs (miRNAs) are small endogenous, non-coding, single-stranded RNAs (approximately 22 nt). Accumulating evidence has shown that aberrant miRNA expression is pronounced and correlated with gastric cancer genesis and progression. Materials and Methods: Expression levels of miR-181a-5p in GC tissues and cell lines were assessed by qRT-PCR and tested for correlation with clinical features. In addition, effects of miR-181a-5p on GC cell growth were investigated. Results: Our findings indicate that miR-181a-5p is upregulated in GC, in correlation with lymph node invasion, nerve invasion and vascular invasion (P<0.05). Enforced expression of miR-181a -5p promoted cell proliferation ability. Conclusions: This study suggested that increased miR-181a-5p is related to GC progression. MiR-181a-5p may represent a potential therapeutic target for GC.Asian Pacific journal of cancer prevention: APJCP 06/2013; 14(6):3871-5. DOI:10.7314/APJCP.2013.14.6.3871 · 2.51 Impact Factor
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ABSTRACT: Chemoresistance is one of the major hurdles to overcome for the successful treatment of breast cancer. At present, there are several mechanisms proposed to explain drug resistance to chemotherapeutic agents, including decreased intracellular drug concentrations, mediated by drug transporters and metabolic enzymes; impaired cellular responses that affect cell cycle arrest, apoptosis, and DNA repair; the induction of signaling pathways that promote the progression of cancer cell populations; perturbations in DNA methylation and histone modifications; and alterations in the availability of drug targets. Both genetic and epigenetic theories have been put forward to explain the mechanisms of drug resistance. Recently, a small non-coding class of RNAs, known as microRNAs, has been identified as master regulators of key genes implicated in mechanisms of chemoresistance. This article reviews the role of microRNAs in regulating chemoresistance and highlights potential therapeutic targets for reversing miRNA-mediated drug resistance. In the future, microRNA-based treatments, in combination with traditional chemotherapy, may be a new strategy for the clinical management of drug-resistant breast cancers.Clinical Epigenetics 08/2011; 2(2):171-185. DOI:10.1007/s13148-011-0040-8 · 6.22 Impact Factor