title: Suppressed miR-424 expression via upregulation of target gene Chk1 contributes to the progression of cervical cancer.
abstract: MicroRNAs (miRNAs) act as important gene regulators in human genomes and their aberrant expression links to many malignancies. We previously identified a different characteristic miRNA expression profile in cervical cancer from that in cervical normal tissues, including the downregulated miR-424. However, the role and mechanism of miR-424 in cervical cancer still remain unknown. Here, we focused on identifying the tumor-suppressive function and clinical significance of miR-424 and exploring the mechanistic relevance by characterizing its target. We showed a significantly decreased expression of miR-424 in 147 cervical cancer tissues versus 74 cervical normal tissues by performing quantitative RT-PCR. In 147 cervical cancer tissue samples, low-level expression of miR-424 was positively correlated with poor tumor differentiation, advanced clinical stage, lymph node metastasis and other poor prognostic clinicopathological parameters. Further in vitro observations showed that enforced expression of miR-424 inhibited cell growth by both enhancing apoptosis and blocking G1/S transition, and suppressed cell migration and invasion in two human cervical cancer cell lines, SiHa and CaSki, implying that miR-424 functions as a tumor suppressor in the progression of cervical cancer. Interestingly, overexpression of miR-424 inhibited the expression of protein checkpoint kinase 1 (Chk1) and phosphorylated Chk1 (p-Chk1) at residues Ser345 and decreased the activity of luciferase-reporter containing the 3'-untranslated region (UTR) of Chk1 with predicted miR-424-binding site. Moreover, miR-424 expression levels were inversely correlated with Chk1 and p-Chk1 protein levels in both cervical cancer and normal tissues. Furthermore, RNAi-mediated knockdown of Chk1 decreased matrix metalloproteinase 9 expression and phenocopied the tumor suppressive effects of miR-424 in cell models. Taken together, our results identify a crucial tumor suppressive role of miR-424 in the progression of cervical cancer at least partly via upreglating the expression of Chk1 and p-Chk1, and suggest that miR-424 might be a candidate of prognostic predictor or an anticancer therapeutic target for cervical cancer patients.
authors.affiliation: Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: Cheng
authors.forename: F
authors.initials: F
authors.lastname: Ye
authors.forename: X
authors.initials: X
authors.lastname: Xie
authors.forename: C
authors.initials: C
authors.lastname: Zhou
authors.forename: W
authors.initials: W
authors.lastname: Lu
mesh_terms: D020413:3' Untranslated Regions; D017209:Apoptosis / Q000235:genetics; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D000071877:Checkpoint Kinase 1; D018450:Disease Progression; D015536:Down-Regulation; D005260:Female; D016193:G1 Phase / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation; D011494:Protein Kinases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D014162:Transfection; D015854:Up-Regulation; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*
chemical_list: D020413:3' Untranslated Regions; C554214:MIRN424 microrna, human; D035683:MicroRNAs; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D020780:Matrix Metalloproteinase 9