title: miR-129 promotes apoptosis and enhances chemosensitivity to 5-fluorouracil in colorectal cancer.
abstract: Resistance to fluoropyrimidine-based chemotherapy is the major reason for the failure of advanced colorectal cancer (CRC) treatment. The lack of ability of tumor cells to undergo apoptosis after genotoxic stress is the key contributor to this intrinsic mechanism. Mounting evidence has demonstrated that non-coding microRNAs (miRNAs) are crucial regulators of gene expression, in particular, under acute genotoxic stress. However, there is still limited knowledge about the role of miRNAs in apoptosis. In this study, we discovered a novel mechanism mediated by microRNA-129 (miR-129) to trigger apoptosis by suppressing a key anti-apoptotic protein, B-cell lymphoma 2 (BCL2). Ectopic expression of miR-129 promoted apoptosis, inhibited cell proliferation and caused cell-cycle arrest in CRC cells. The intrinsic apoptotic pathway triggered by miR-129 was activated by cleavage of caspase-9 and caspase-3. The expression of miR-129 was significantly downregulated in CRC tissue specimens compared with the paired normal control samples. More importantly, we demonstrated that miR-129 enhanced the cytotoxic effect of 5-fluorouracil both in vitro and in vivo. These results suggest that miR-129 has a unique potential as a tumor suppressor and a novel candidate for developing miR-129-based therapeutic strategies in CRC.
authors.affiliation: Translational Research Laboratory, Department of Pathology, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: M
authors.initials: M
authors.lastname: Karaayvaz
authors.forename: H
authors.initials: H
authors.lastname: Zhai
authors.forename: J
authors.initials: J
authors.lastname: Ju
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis; D001483:Base Sequence; D001665:Binding Sites; D059447:Cell Cycle Checkpoints; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D050699:E2F3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005472:Fluorouracil / Q000494:pharmacology*; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D034622:RNA Interference; D023041:Xenograft Model Antitumor Assays
chemical_list: D020413:3' Untranslated Regions; D000964:Antimetabolites, Antineoplastic; D050699:E2F3 Transcription Factor; C098319:E2F3 protein, human; D035683:MicroRNAs; C541915:Mirn129 microRNA, human; D019253:Proto-Oncogene Proteins c-bcl-2; D005472:Fluorouracil