title: High-dose chemotherapeutics of intravesical chemotherapy rapidly induce mitochondrial dysfunction in bladder cancer-derived spheroids.
abstract: Non-muscle invasive bladder cancer is treated with intravesical chemotherapy (IVC) after transurethral resection (TUR) to reduce the probability of recurrence. Despite improvement, the recurrence rate remains high. Intravesical chemotherapeutics at high doses are expected to ablate unresected tumors and floating cancer cells after TUR, although the fate of bladder cancer cells exposed to high-dose chemotherapeutics remains unclear. In this study, we utilized cancer tissue-originated spheroids (CTOS) prepared from bladder cancers or patient-derived xenografts, which may recapitulate human tumors better than 2-D cultures of established cell lines. We exposed CTOS to 1 mg/mL of epirubicin (EPI) or mitomycin C (MMC) for 2 h. EPI was promptly and homogeneously distributed into cancer cells in the CTOS. Two hours after exposure to MMC, the mitochondrial membrane potential decreased and the mitochondria were fragmented, while plasma membrane integrity was maintained. ATP levels rapidly decreased in CTOS after exposure to EPI or MMC. Although activation of the apoptotic pathway was confirmed by the advent of cleaved poly (ADP-ribose) polymerase, fragmentation of DNA (a hallmark of apoptosis) was not observed in CTOS after exposure to EPI and MMC. In the CTOS prepared directly from 19 surgical specimens exposed to EPI and MMC, the decrease of ATP levels varied among patients. Further establishment of the test might help the drug selection and the prediction of recurrence for individual patients.
authors.affiliation: Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan; Department of Urology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okuyama
authors.forename: Masashi
authors.initials: M
authors.lastname: Nakayama
authors.forename: Hiroko
authors.initials: H
authors.lastname: Endo
authors.forename: Norio
authors.initials: N
authors.lastname: Nonomura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nishimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000283:Administration, Intravesical; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D053938:DNA Fragmentation; D015251:Epirubicin / Q000494:pharmacology; D006801:Humans; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D016685:Mitomycin / Q000494:pharmacology; D009368:Neoplasm Transplantation; D018874:Spheroids, Cellular / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000473:pathology*
chemical_list: D000970:Antineoplastic Agents; D015251:Epirubicin; D016685:Mitomycin
keywords: 3-D culture; bladder cancer; cell death; chemosensitivity; intravesical chemotherapy