ERBB2 gene expression silencing involved in ovarian cancer cell migration and invasion through mediating MAPK1/MAPK3 signaling pathway.

ABSTRACT

OBJECTIVE: To explore possible mechanism of ERBB2 gene expression silencing mediating mitogen-activated protein kinase 1/mitogen-activated protein kinase 3 (MAPK1/MAPK3) signaling pathway on proliferation, migration, and invasion of ovarian cancer cells. PATIENTS AND METHODS: A total of 240 cancer specimens were collected in patients with epithelial ovarian cancer intraoperatively in our hospital from January 2015 to January 2018. Expressions of ERBB2, MAPK1, and MAPK3 in tissues were detected by immunohistochemistry. Following the culture of ovarian cancer cell lines, target cell line with high expression of ERBB2 was screened by qRT-PCR. Cell grouping was performed with four groups after transfection, including Blank group, negative control (NC) group, ERBB2 shRNA group, and ERBB2 overexpression group (shorted as ERBB2 group). The expression levels of ERBB2, MAPK1, MAPK3, vascular endothelial growth factor (VEGF), metalloproteases-2 (MMP-2), and tissue inhibitor of metalloproteases-2 (TIMP-2) were detected by qRT-PCR in different transfection groups, followed by the detection of protein expressions with Western blot. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to test the proliferation activity of each group after transfection, while transwell assay and scratch test explored cell invasion and migration in each group, respectively. RESULTS: Immunohistochemistry showed that the positive rates of ERBB2, MAPK1, and MAPK3 in ovarian cancer tissues were significantly increased than those in adjacent normal epithelial tissues. In the cell experiment, ERBB2 gene was highly expressed in SKOV3 ovarian cancer cell line. There was no significant difference in each index between Blank group and NC group (p > 0.05). Compared with Blank group and NC group, the expression levels of ERBB2, MAPK1, MAPK3, VEGF, and MMP-2 in ERBB2 shRNA group decreased significantly, TIMP-2 increased markedly, and proliferation, invasion, and migration abilities of cells decreased markedly after transfection, showing statistically significant differences (All p < 0.05). By contrast, the expression levels of ERBB2, MAPK1, MAPK3, VEGF, and MMP-2 increased remarkably in ERBB2 group, while TIMP-2 decreased significantly, and cell proliferation, invasion, and migration ability increased evidently after transfection, with statistically significant differences (All p < 0.05). CONCLUSIONS: Silencing ERBB2 gene expression may inhibit the activation of MAPK1/MAPK3 signaling pathway and thus suppress the proliferation, invasion, and migration of ovarian cancer cells. Overexpression of ERBB2 gene can reverse those trends, which in turn support the role of ERBB2 gene expression silencing in molecular targeted therapy of ovarian cancer.