ABSTRACT
【Objective】 To explore the expressions of PBRM1 and PD-L1 in renal cell carcinoma (RCC), and the molecular mechanism of PBRM1 regulating PD-L1, in order to provide experimental results for clinical immunotherapy. 【Methods】 The protein expressions of PBRM1 and PD-L1 were detected with immunohistochemistry, and their mRNA expressions were determined by analyzing TCGA database. Meanwhile, the relationship between overall survival and mRNA expressions of PBRM1 and PD-L1 were analyzed in TCGA database. The exosomes were extracted with exoEasy Maxi Kit. Expressions of exosomal biomarkers CD63 and CD9 were detected with Western blotting, and their morphology was observed with transmission electron microscope. PD-L1 expression after IFN-γ, IL-6 and TNF-α treatment was detected with Western blotting. 【Results】 The expression of PBRM1 was significantly lower in canver tissue than in paracancerous tissue (P<0.001). The loss rate of PBRM1 was up to 76.4%. PBRM1 expression was not correlated with PD-L1 expression. PBRM1 deletion activated TNF-α/exosome signaling pathway, leading to increase of PD-L1 secretion in exosomes, which was then transported to the outside of cells. 【Conclusion】 There is no relationship between PBRM1 and PD-L1 protein expressions in RCC. However, PBRM1 mutation can lead to inflammatory signaling pathway activation, inducing PD-L1 secretion, which is encapsulated in exosomes and transported to the outside of cells, and affects the response of immunotherapy.
ABSTRACT
Abstract Objectives The pathological mechanisms of patients with Renal Cell Carcinoma (RCC) remain defined. This study aimed to evaluate relationships between the landscape of gene mutations and their clinical significance in RCC patients. Methods Tissue and peripheral blood samples of 42 patients with RCC were collected and performed for the Next Generation Sequencing (NGS) with Geneseeq PrimeTM 425-gene panel probes. Their landscapes of gene mutation were analyzed. We also carried out an evaluation of Tumor-Node-Metastasis (TNM) staging, RENAL nephelometry score, surgery, and targeted drug treatment of patients. Then we compared the correlations of landscape in gene mutations and the prognosis. Results The most common gene alternations, including BAP1, PBRM1, SETD2, CSF1R, NPM1, EGFR, POLE, RB1, and VHL genes, were identified in tissue and blood samples of 75% of patients. EGFR, POLE, and RB1 gene mutations frequently occurred in relapsed and metastatic patients. BAP1, CCND2, KRAS, PTPN11, ERBB2/3, JAK2, and POLE were presented in the patients with > 9 RENAL nephelometry score. Univariable analysis indicated that SETD2, BAP1, and PBRM1 genes were key factors for Disease-Free Survival (DFS). Multivariable analysis confirmed that mutated SETD1, NPM1, and CSF1R were critical factors for the Progression Free Survival (PFS) of RCC patients with target therapy. Conclusions Wild-type PBRM1 and mutated BAP1 in patients with RCC were strongly associated with the outcomes of the patient. The PFS of the patients with SETD2, NPM1, and CSF1R mutations were significantly shorter than those patients without variants.