Presentation Authors: yu zeng*, zi yu, shui fu, gejun zhang, Chengcheng Lv, Qingzhuo Dong, Chuize Kong, Cheng Fu, Shenyang, China, People's Republic of
Introduction: Renal cell carcinoma (RCC) is the most common type of kidney cancer word widely. Although target therapy and checkpoint immunotherapy improve the survival of metastatic RCC, a large number of patients are still incurable.
Methods: The raw RNA-sequencing data of RCC were download from the Cancer Genome Atlas (TCGA) database and exported by using R-project. A high-content cell viability assay was used to screen genes those are potentially regulating cell proliferation after downregulating the mRNA expressions of each gene by shRNA. RT-PCR was conducted to detect the mRNA expression of pleckstrin homology domain containing O1 (PLEKHO1) gene in 30 paired localized tumor and para-tumor kidney tissue samples. The effects of lowering the expression of PLEKHO1 were assessed by CCK-8 assay, Celigo assay, flow cytometry and transwell assay, separately. Additionally, xenograft tumor models were established in nude mice to investigate the function of PLEKHO1 in vivo. Gene expression microarray and co-expression analysis followed by Western blot were further conducted to explore the involvement of PLEKHO1 in signalling pathways.
Results: Sixteen genes were identified to be consistently highly expressed in ccRCC tissue compared with the matched para-tumor tissue in TCGA data set, while downregulation of only two of those significantly inhibited the viability of RCC cells. Among two genes, PLEKHO1 was unknown in its relevance to RCC and its expression level was shown to be associated with prognosis of RCC in the TCGA data set. Next, upregulation of PLEKHO1 mRNA was confirmed in RCC tissue samples. Reducing the expression of PLEKHO1 by specific siRNAs significantly inhibited cell viability and cell migration, and facilitated apoptosis in 786-0 and Caki-1 cells. In addition, knocking-down the expression of PLEKHO1 greatly impeded xenografted tumorâ€™s growth in nude mice. Finally, signalling pathways exploring by microarray analysis indicated that PLEKHO1-knockdown decreased the expressions of TAZ and CTGF, which are two key factors in HIPPO signalling pathway, and simultaneously reduced the expressions of p-JNK and c-Jun, which are two key factors in the JNK signalling pathway, in 786-O cells.
Conclusions: These results suggest that the aberrant expression of PLEKHO1 in RCC may contribute to tumor growth, and therefore the potential of PLEKHO1 as a therapeutic target needs to be further studied.
Source of Funding: National Natural Science Foundation of China (grant nos. 81372766 and 81572532), and the Liaoning â€œClimbingâ€ scholarship.