Correspondingly, up-regulation of PAX3 was observed in various human gastric cancer cell lines, especially invasive HDAC inhibitor cell lines (MKN28-M,
SGC7901-M). Silencing of PAX3 in MKN28-M and SGC7901-M cells down-regulated MET receptor expression and attenuated cell invasion in vitro and in vivo; in contrast, ectopic expression of PAX3 generated opposite effects. Furthermore, PAX3 and MET expression exhibited a significant positive correlation in GC tissues. Conclusion: These findings suggested that PAX3 might be an intrinsic regulator of progression in GC cells and it might serve as a novel prognostic factor for patients with gastric carcinoma. Key Word(s): 1. The paired box 3 ; 2. gastric cancer; 3. MET; 4. Metastasis; Presenting
Author: YU CHEN Additional Authors: LU WANG, LINA CUI, YONGQUAN SHI, YING HAN, KAICHUN WU, DAIMING FAN Corresponding Author: YING HAN, KAICHUN WU Affiliations: Xijing Hospital of Digestive Diseases Objective: Cancer changes biological processes in the liver at multiple levels, including potently modulation of gene expression posttranscriptionally through microRNAs and RNA binding proteins. RhoA, as one of Rho GTPases, is well known to regulate cell motility through activation of a variety of downstream effector proteins, including enzymes, adaptor proteins and actin nucleators. However, its posttranscriptional regulation remains unclear. Recent study in our lab showed that RhoA is highly expressed in hepatocarcinoma, and its expression level could be significantly repressed by miR-195. HuR, a central RNA-binding protein regulating cell dedifferentiation, VX-765 nmr proliferation, and survival, Reverse transcriptase is also highly expressed in HCC. Based
on computationally predicted HuR and miR-195 associations with the RhoA mRNA, this study tests the hypothesis that HuR and miR-195 jointly regulate RhoA expression in HCC and therefore the HCC metastasis. Methods: The expression of miR-195, RhoA and HuR in clinical samples were measured by q-PCR, western and immunohistochemistry respectively. The interaction of HuR and RhoA mRNA was detected by biotin pull-down and RNP-IP assays. The miR-195 binding to RhoA transcript was examined by RNA pull-down assay using biotin-labeled miR-195. RhoA translation was examined by using the chimeric luciferase (Luc)- RhoA coding region (CR) and 3′-untranslated region (UTR) reporter gene assays and newly protein synthesis. HuR and miR-195 functions were investigated by siRNA silencing and ectopic gene overexpression. Cell metastasis ability was measured by wounding assay, transwell assay and nude mice transplant assay. Results: RhoA mRNA is a target of HuR and miR-195. Both HuR and miR-195 directly bound to the RhoA 3′-UTR. Mapping experiments and studies using heterologous reporter constructs revealed that there were significant overlaps between HuR- and miR-195-binding sites on the RhoA 3′-UTR.