Expression And Functional Research Of CAPN2 In Renal Cell Carcinoma

Background: The calpain 2(CAPN2)is upregulated in various malignant carcinomas.Previous studies have declared that CAPN2 functioned as an oncogenic factor in human tumors.However,its clinical role and potential effect on cell metastasis and proliferation in renal cell carcinoma(RCC)remain unknown.Methods: In this study,we evaluated the m RNA and protein levels of CAPN2 in RCC cell lines and 30 human RCC specimens,adjacent normal specimens using quantitative Real-time PCR(RT-PCR)and Western Blot.Immunohistochemistry of 74 RCC tissues in a tissue microarrays(TMAs)and normal kidney tissues were performed.Kaplan-Meier survival curve analyses were conducted to measure the correlation between CAPN2 expression and patients' prognosis.Cell migrative,invasive ability and cell proliferation were measured by Transwell and Cell Counting Kit-8(CCK-8)assays.Results: CAPN2 exhibited a significant overexpression in human RCC tissues and cell lines compared with adjacent non-tumor tissues and normal human proximal tubule epithelial cell line HK-2.Strong staining of CAPN2 was associated with higher clinical stage and histological grade.In addition,downregulation of CAPN2 could signifcantly inhibit migration,invasion and proliferation of 769-P and Caki-1 cells.Conversely,increased cell biological behaviors were observed in CAPN2-OV(CAPN2-Overexpression)Caki-2 cells.In vivo,results revealed that the tumor sizes of sh-CAPN2 group were significantly smaller than the NC group(* P < 0.05).Remedial experiments showed that the addition of phosphorylation-Akt inhibitor MK2206 could inhibit the promoting role of CAPN2-OV in the biological behavior of renal cell carcinoma,while the level of phosphorylation-Akt(p-Akt)also decreased significantly.Moreover,subsequent mechanism investigation suggested that CAPN2 promoted RCC progression by activating Akt/m TOR signaling,enhancing epithelial mesenchymal transition(EMT)and MMP9 expression levels.Conclusion: Our results detected that CAPN2 exhibited a promoting role in RCC metastasis and proliferation via activiating Akt/m TOR signaling pathway.CAPN2 may act as a prominent indicator for RCC progression and a novel therapeutic target for RCC patients.