RKIP inhibits gastric cancer cell survival and invasion by regulating the expression of HMGA2 and OPN.

Abstract

The objective of this study was to explore the mechanism via which Raf kinase inhibitor protein (RKIP) suppresses the invasion of gastric cancer cells and promote apoptosis, with an attempt to provide evidences for the application of RKIP in treating gastric cancer. The recombinant plasmid pcDNA3.1-RKIP or RKIP-shRNA was transfected into the gastric cancer cell line SGC-7901 using liposome. Then, the messenger RNA (mRNA) and protein expressions of RKIP, HMGA2, and OPN were detected using qPCR and Western blotting. The effects of HMGA2 on the proliferation, apoptosis, and invasion of SGC-7901 cells were detected using flow cytometry and Transwell assay. To further explore the regulatory effect of PKIP on the biological activities of HMGA2, we over-expressed or knock down RKIP and HMGA2 simultaneously and detected its effects on the proliferation, apoptosis, and invasion of SGC-7901 cells. As shown by qPCR and Western blotting, after over-expression of RKIP in SGC-7901 cells, the mRNA and protein expressions of RKIP significantly increased (P < 0.01), whereas the mRNA and protein expressions of HMGA2 and OPN significantly decreased (P < 0.01). In contrast, the transfection of RKIP-shRNA in the SGC-7901 cells resulted in opposite results. After over-expression of HMGA2 in SGC-7901 cells, the protein expression of HMGA2 significantly increased (P < 0.01); however, it significantly decreased after the transfection of HMGA2-shRNA (P < 0.01). As shown by Transwell assay and flow cytometry, After the over-expression of HMGA2 in SGC-7901 cells, the (G2 + S) phase fraction significantly increased (P < 0.01); also, the percentage of the apoptotic cells significantly declined (P < 0.05) and the number of invasive cells significantly increased (P < 0.05). However, the interference of the expression of HMGA2 resulted in opposite results. The simultaneous over-expression of RKIP and HMGA2 in SGC-7901 cells or the simultaneous interference of RKIP and HMGA2 showed no significant difference with the control group in terms of (G2 + S) phase fraction, percentage of apoptotic cells, and number of invasive cells (P > 0.05). In conclusion, RKIP can inhibit the survival and invasion of gastric cancer cells and promote apoptosis, possibly by regulating the expression of HMGA2 or OPN.

• Authors: Hongyi Liu, Peng Li, Bing Li, Peng Sun, Jiajin Zhang, Baishi Wang, Baoqing Jia
• Journal: Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine (Tumour Biol) Vol. 35 Issue 12 Pg. 11949-58 (Dec 2014) ISSN: 1423-0380 [Electronic] Netherlands
• PMID: 25172097 (Publication Type: Journal Article)

Chemical References

• HMGA2 Protein
• Phosphatidylethanolamine Binding Protein
• Osteopontin

Topics

• Apoptosis (genetics)
• Cell Line, Tumor
• Cell Proliferation
• Cell Survival (genetics)
• Cells, Cultured
• Gene Expression Regulation, Neoplastic
• HMGA2 Protein (genetics)
• Humans
• Osteopontin (genetics)
• Phosphatidylethanolamine Binding Protein (genetics, metabolism)
• Stomach Neoplasms (genetics, metabolism, pathology)