title: MLN2238 synergizes BH3 mimetic ABT-263 in castration-resistant prostate cancer cells by induction of NOXA.
abstract: Patients undergoing androgen blockade therapy develop castration-resistant prostate cancer (CRPC), which is associated with Bcl-2 upregulation and results in disease progression and death. In recent years, promising therapeutic agents, such as the BH3-only mimetic ABT-263 and proteasome inhibitors, have been developed and widely evaluated against a broad spectrum of cancer types, including prostate cancer, alone or in combination with other chemotherapeutic agents. In this study, the antitumor efficacy of ABT-263 and MLN2238 were evaluated as single agents and in combination in four CRPC cell lines: PC3, C4-2B, C4-2, and DU145. The viability of the treated cells and markers of apoptosis were assayed. Protein-protein interactions were analyzed by co-immunoprecipitation in drug-treated cells. Lentivirus-mediated short hairpin RNA was used to knockdown Bax, Mcl-1, and NOXA expressions. We found that ABT-263 and MLN2238 alone exhibited a mild cytotoxicity, and in combination, they elicited a synergistic cytotoxic effect in CRPC cells. The cell apoptosis induced by the combination drug treatment was evidenced by enhanced caspase-3 and Poly (ADP-ribose) polymerase (PARP) cleavage, and annexin-V-positive staining was significantly depleted by Bax knockdown. MLN2238 treatment upregulated NOXA and Mcl-1 expression, leading NOXA/Mcl-1 complexes to disassociate Bak from its complexes with Mcl-1 and enhancing ABT263-triggered Bax activation. NOXA knockdown by short hairpin RNA significantly attenuated the cytotoxicity of ABT-263 and MLN2238 co-administration. In conclusion, MLN2238 and ABT-263 synergistically triggered apoptosis in CRPC cells by upregulating NOXA and activating Bax, indicating a promising therapeutic strategy for the treatment of CRPC.
authors.affiliation: Department of Urology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, 510180, China.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Wei
authors.forename: Ping
authors.initials: P
authors.lastname: Zhou
authors.forename: Xuanting
authors.initials: X
authors.lastname: Lin
authors.forename: Yurong
authors.initials: Y
authors.lastname: Lin
authors.forename: Sifeng
authors.initials: S
authors.lastname: Wu
authors.forename: Pengfei
authors.initials: P
authors.lastname: Diao
authors.forename: Haiqing
authors.initials: H
authors.lastname: Xie
authors.forename: Keji
authors.initials: K
authors.lastname: Xie
authors.forename: Ping
authors.initials: P
authors.lastname: Tang
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D051023:BH3 Interacting Domain Death Agonist Protein / Q000819:agonists; D001896:Boron Compounds / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008297:Male; D064129:Prostatic Neoplasms, Castration-Resistant / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D034741:RNA, Small Interfering; D013449:Sulfonamides / Q000494:pharmacology*; D014162:Transfection
chemical_list: D000814:Aniline Compounds; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D001896:Boron Compounds; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D013449:Sulfonamides; C548400:ixazomib; D005998:Glycine; C528561:navitoclax