Cisplatin-induced downregulation of miR-199a-5p increases drug resistance by activating autophagy in HCC cell.

Department of Transplantation and Hepatic Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, 1630 Dongfang Road, Shanghai 200127, People's Republic of China.
Biochemical and Biophysical Research Communications (Impact Factor: 2.28). 06/2012; 423(4):826-31. DOI: 10.1016/j.bbrc.2012.06.048
Source: PubMed

ABSTRACT Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Systemic chemotherapy plays an important role in the treatment of patients with advanced liver cancer. However, chemoresistance to cisplatin is a major limitation of cisplatin-based chemotherapy in the clinic, and the underlying mechanism of such resistance is not fully understood. In the study, we found that miR-199a-5p levels were significantly reduced in HCC patients treated with cisplatin-based chemotherapy. Cisplatin treatment also resulted in decreased miR-199a-5p levels in human HCC cell lines. Forced expression of miR-199a-5p promoted cisplatin-induced inhibition of cell proliferation. Cisplatin treatment activated autophagy in Huh7 and HepG2 cells, which increased cell proliferation. We further demonstrated that downregulated miR-199a-5p enhanced autophagy activation by targeting autophagy-associated gene 7 (ATG7). More important, autophagy inhibition abrogated miR-199a-5p downregulation-induced cell proliferation. These data demonstrated that miR-199a-5p/autophagy signaling represents a novel pathway regulating chemoresistance, thus offering a new target for chemotherapy of HCC.

  • [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs are regulatory factors that play important roles in tumor development, invasion and metastasis. Previously, we showed that miR-199a is abnormally expressed in clinical melanoma specimens and expression was closely associated with clinical features of metastasis. However, the exact molecular mechanisms by which miR-199a-5p influences melanoma invasion and metastasis remains unclear. In this study, we investigated gene expression changes of metastasis-associated genes in B16F10 melanoma cells following targeted silencing or overexpression of miR-199a-5p, using mouse tumor metastasis PCR arrays. Comparison of gene expression changes in miR-199a-5p-silenced versus overexpressing cells identified a set of upregulated genes (> 2-fold) including Cd44, Cdh1, Cxcr4, Etv4, Fxyd5, Rpsa, Mmp3, Myc, Rb1, Tcf20, Hprt1, Actb1 and downregulated genes (> 2-fold) including Ctsk, Itga7 and Tnfsf10. Regulation of a subset of these genes (Myc, Tnfsf10 and Cd44) following miR-199a-5p silencing or overexpression was validated by reverse transcription-polymerase chain reaction (RT-PCR) and western blot. In conclusion, our study demonstrates that miR-199a-5p regulates melanoma metastasis-related genes, and may provide a basis for the development of novel, molecularly targeted drugs.
    International journal of clinical and experimental pathology. 01/2014; 7(10):7182-90.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: First discovered in 1993, microRNAs (miRNAs) have been one of the hottest research areas over the past two decades. Oftentimes, miRNAs levels are found to be dysregulated in cancer patients. The potential use of miRNAs in cancer therapies is an emerging and promising field, with research finding miRNAs to play a role in cancer initiation, tumor growth, and metastasis. Therefore, miRNAs could become an integral part from cancer diagnosis to treatment in future. This review aims to examine current novel research work on the potential roles of miRNAs in cancer therapies, while also discussing several current challenges and needed future research.
    BioMed Research International 01/2014; 2014:959461. · 2.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: miRNAs are short, noncoding RNAs that regulate expression of target genes at post-transcriptional levels and function in many important cellular processes, including differentiation, proliferation, etc. In this study, we observed down-regulation of miR-199a-5p during monocyte/macrophage differentiation of HL-60 and THP-1 cells, as well as human CD34(+) HSPCs. This down-regulation of miR-199a-5p resulted from the up-regulation of PU.1 that was demonstrated to regulate transcription of the miR-199a-2 gene negatively. Overexpression of miR-199a-5p by miR-199a-5p mimic transfection or lentivirus-mediated gene transfer significantly inhibited monocyte/macrophage differentiation of the cell lines or HSPCs. The mRNA encoding an ACVR1B was identified as a direct target of miR-199a-5p. Gradually increased ACVR1B expression level was detected during monocyte/macrophage differentiation of the leukemic cell lines and HSPCs, and knockdown of ACVR1B resulted in inhibition of monocyte/macrophage differentiation of HL-60 and THP-1 cells, which suggested that ACVR1B functions as a positive regulator of monocyte/macrophage differentiation. We demonstrated that miR-199a-5p overexpression or ACVR1B knockdown promoted proliferation of THP-1 cells through increasing phosphorylation of Rb. We also demonstrated that the down-regulation of ACVR1B reduced p-Smad2/3, which resulted in decreased expression of C/EBPα, a key regulator of monocyte/macrophage differentiation, and finally, inhibited monocyte/macrophage differentiation.
    Journal of Leukocyte Biology 09/2014; · 4.30 Impact Factor