Bladder cancer cell-intrinsic PD-L1 signals promote mTOR and autophagy activation that can be inhibited to improve cytotoxic chemotherapy

Deyi Zhang, Ryan M. Reyes, Erica Osta, Suresh Kari, Harshita B. Gupta, Alvaro S. Padron, Anand V.R. Kornepati, Aravind Kancharla, Xiujie Sun, Yilun Deng, Bogang Wu, Ratna Vadlamudi, Rong Li, Robert S. Svatek, Tyler J. Curiel

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Tumor cell-intrinsic programmed death-ligand 1 (PD-L1) signals mediate immunopathologic effects in breast, colon, and ovarian cancers and in melanomas, but bladder cancer (BC) effects are unreported. We show here that BC cell-intrinsic PD-L1 signals in mouse MB49 and human RT4, UM-UC3, and UM-UC-14 BC cells regulate important pathologic pathways and processes, including effects not reported in other cancers. α-PD-L1 antibodies reduced BC cell proliferation in vitro, demonstrating direct signaling effects. BC cell-intrinsic PD-L1 promoted mammalian target of rapamycin complex 1 (mTORC1) signals in vitro and augmented in vivo immune-independent cell growth and metastatic cancer spread, similar to effects we reported in melanoma and ovarian cancer. BC cell-intrinsic PD-L1 signals also promoted basal and stress-induced autophagy, whereas these signals inhibited autophagy in melanoma and ovarian cancer cells. BC cell-intrinsic PD-L1 also mediated chemotherapy resistance to the commonly used BC chemotherapy agents cis-platinum and gemcitabine and to the mTORC1 inhibitor, rapamycin. Thus, BC cell-intrinsic PD-L1 signals regulate important virulence and treatment resistance pathways that suggest novel, actionable treatment targets meriting additional studies. As a proof-of-concept, we showed that the autophagy inhibitor chloroquine improved cis-platinum treatment efficacy in vivo, with greater efficacy in PD-L1 null versus PD-L1-replete BC.

Original languageEnglish (US)
Pages (from-to)2137-2152
Number of pages16
JournalCancer Medicine
Volume10
Issue number6
DOIs
StatePublished - Mar 2021

Keywords

  • PD-L1
  • autophagy
  • bladder cancer
  • chemotherapy
  • mTOR

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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