MP04-16 EPITHELIAL TO MESENCHYMAL TRANSITION PROMOTES PD-L1 EXPRESSION IN RENAL CELL CARCINOMA

Abstract

You have accessJournal of UrologyCME1 Apr 2023MP04-16 EPITHELIAL TO MESENCHYMAL TRANSITION PROMOTES PD-L1 EXPRESSION IN RENAL CELL CARCINOMA Allison May, Jonathan Jiang, Tyler Robinson, and Evan Keller Allison MayAllison May More articles by this author , Jonathan JiangJonathan Jiang More articles by this author , Tyler RobinsonTyler Robinson More articles by this author , and Evan KellerEvan Keller More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003215.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Sarcomatoid dedifferentiation in renal cell carcinoma (RCC) is thought to occur when the parental cell type, such as clear cell RCC (ccRCC), undergoes an epithelial mesenchymal transition (EMT). The mesenchymal sarcomatoid cells have increased ability to invade and metastasize, and thus sarcomatoid RCC (sRCC) has a very poor prognosis. Interestingly however, there is encouraging evidence that sRCC responds at higher rates to PD-1/PD-L1 directed immunotherapy than ccRCC. We aim to test the hypothesis that EMT directly upregulates PD-L1 expression in sRCC and that PD-L1 may have positive feedback on induction of EMT. METHODS: Baseline expression of EMT markers, EMT transcription factors and PD-L1 were measured using Western Blot and qPCR in two clear cell RCC lines (Caki-1 and 786-O) and five sarcomatoid RCC lines (RCJ-41T1, RCJ-41T2, RCJ-41M, UOK-276, UOK-127). EMT was induced in the cells through treatment with multiple agents including TGFB, IFNg, HGF, SPP1, and CoCl2 and by over expression of Snail or Zeb1. Effect of EMT on PD-L1 expression was measured. To evaluate the role of PD-L1 on EMT, PD-L1 expression was decreased using siRNA and its effect on EMT related protein expression was measured using Western Blot. RESULTS: At baseline, sRCC cell lines generally had higher expression of EMT related markers and transcription factors than ccRCC lines. Baseline PD-L1 expression positively correlated with increasing EMT state in all cell lines. Treatment of cells with known EMT inducers, TGFB, IFNg, and hypoxia led to increased levels of mesenchymal marker N-cadherin, decreased epithelial marker E-cadherin, and increased levels of EMT transcription factors Zeb1, Snail, and Slug. Treatment of cells with HGF and SPP1, two molecules associated with sRCC based on our prior work, also induced EMT. Finally, over expression of known EMT transcription factors Snail and Zeb1 led to EMT as well. All methods of EMT induction concomitantly increased PD-L1 expression. Knockdown of PD-L1 was tested in UOK-276 and 786-O cells and led to decreased expression levels of EMT transcription factors and increased epithelial markers. CONCLUSIONS: These data support the theory that sRCC arises from EMT and that EMT directly leads to upregulation of PD-L1. Furthermore, these results suggest that PD-L1 maintains the mesenchymal state. These findings may help explain the enhanced response to PD-1/PD-L1 directed therapy in sRCC and suggest that markers of EMT state could represent a biomarker for immunotherapy response in RCC. Source of Funding: Clarke Family Fellowship for Kidney Cancer Research © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e39 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Allison May More articles by this author Jonathan Jiang More articles by this author Tyler Robinson More articles by this author Evan Keller More articles by this author Expand All Advertisement PDF downloadLoading ...