MP01-07 MITOMYCIN C SENSITIVE TUMOR CELLS GENERATE AN INFLAMMATORY SECRETOME CAPABLE OF INDUCING ANTI-TUMOR IMMUNE RESPONSES

Abstract

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology I (MP01)1 Apr 2020MP01-07 MITOMYCIN C SENSITIVE TUMOR CELLS GENERATE AN INFLAMMATORY SECRETOME CAPABLE OF INDUCING ANTI-TUMOR IMMUNE RESPONSES Bianca Oresta*, Chiara Pozzi, Daniele Braga, Rodolfo Hurle, Massimo Lazzeri, Nicola Frego, Cristina Faccani, Paolo Casale, Giorgio Guazzoni, Maria Rescigno, and Bianca Oresta Bianca Oresta*Bianca Oresta* More articles by this author , Chiara PozziChiara Pozzi More articles by this author , Daniele BragaDaniele Braga More articles by this author , Rodolfo HurleRodolfo Hurle More articles by this author , Massimo LazzeriMassimo Lazzeri More articles by this author , Nicola FregoNicola Frego More articles by this author , Cristina FaccaniCristina Faccani More articles by this author , Paolo CasalePaolo Casale More articles by this author , Giorgio GuazzoniGiorgio Guazzoni More articles by this author , Maria RescignoMaria Rescigno More articles by this author , and Bianca OrestaBianca Oresta More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000815.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Despite preventing recurrence of non-muscle invasive bladder cancer (BC), the chemotherapeutic drug Mitomycin C (MMC) is effective only in a proportion of patients. We speculated that treatment success might not only rely on MMC cytotoxic potential, but also on its ability to trigger immunogenic cell death (ICD). In this study, we assessed MMC-induced ICD in a panel of BC cell lines and we investigated the molecular differences between ICD-responsive and ICD-resistant resistant BC cells to identify potential underlying mechanisms of MMC efficacy. METHODS: Human BC cell lines were treated or not with MMC and expression of ICD markers was then assessed by flow cytometry and enzyme-linked immunosorbent assay. The ability of dendritic cells (DCs) to phagocytose tumor cells and undergo maturation was analyzed after 2h or 24h coculture by flow cytometry. Illumina mRNA sequencing was used to screen for differentially expressed genes between ICD-responsive and not responsive BC cell lines. RESULTS: Treatment with MMC fostered ICD in some BC cells by inducing endoplasmic reticulum stress response, increased secretion of the damage signal high-mobility-group box 1 (HMGB1), and augmented DC-mediated phagocytic clearance of treated tumor cells compared to untreated cells. However, some tumor cells did not undergo ICD upon treatment with MMC. RNA sequencing analysis of ICD-responsive and ICD-resistant tumor cells showed that responsive cells were characterized by the expression of a specific signature characterized by the upregulation of genes involved in immune functions, including: response to cytokines, inflammation and regulation of innate and adaptive immune response. Among the most upregulated genes in the ICD signature we found proinflammatory cytokines, chemotactic molecules that control the migration and adhesion of monocytes, neutrophils, and lymphocytes. Moreover, we observed that pathways related to the regulation of cell cycle, spindle formation, sister chromatid segregation, and protein processing were specifically downregulated in ICD-responsive cells, indicating that MMC treatment in these cells induced an early block in the replication machinery, stopped in cell cycle progression, leading to cytotoxicity. On the contrary, ICD-resistant cells did not upregulate the expression of inflammatory mediators and showed fewer changes in gene expression upon MMC treatment compared to all the ICD responsive cell lines. We found that only ICD-responsive BC cell lines secreted IL-1β, IL-6 and IL-8 upon treatment with MMC, which induced DC maturation, a crucial step for proper priming of adaptive immunity. CONCLUSIONS: Overall, we showed a novel immune-related mechanism of action of MMC that may be exploited to optimize bladder cancer management and identify ICD-related biomarkers. Source of Funding: Ricerca FinalizzataMinistero della Salute-Italy © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e4-e4 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Bianca Oresta* More articles by this author Chiara Pozzi More articles by this author Daniele Braga More articles by this author Rodolfo Hurle More articles by this author Massimo Lazzeri More articles by this author Nicola Frego More articles by this author Cristina Faccani More articles by this author Paolo Casale More articles by this author Giorgio Guazzoni More articles by this author Maria Rescigno More articles by this author Bianca Oresta More articles by this author Expand All Advertisement PDF downloadLoading ...