title: APR-246 overcomes resistance to cisplatin and doxorubicin in ovarian cancer cells.
abstract: Two main causes of platinum resistance are mutation in the tumor suppressor gene TP53 and drug-induced increase in intracellular glutathione concentration. Mutations in TP53 occur in about 50% of human tumors. APR-246 (PRIMA-1(MET)) is the first clinical-stage compound that reactivates mutant p53 and induces apoptosis. APR-246 is a prodrug that is converted to the active compound methylene quinuclidinone (MQ), a Michael acceptor that binds to cysteine residues in mutant p53 and restores its wild-type conformation. Here, we show that MQ also binds to cysteine in glutathione, thus decreasing intracellular free glutathione concentration. We also show that treatment with APR-246 completely restores the cisplatin and doxorubicin sensitivity to p53-mutant drug-resistant ovarian cancer cells. We propose that this unique ability of APR-246/MQ to bind to cysteines in both mutant p53 and glutathione has a key role in the resensitization as well as in the outstanding synergistic effects observed with APR-246 in combination with platinum compounds in ovarian cancer cell lines and primary cancer cells. However, MQ binding to cysteines in other targets, for example, thioredoxin reductase, may contribute as well. Strong synergy was also observed with the DNA-damaging drugs doxorubicin and gemcitabine, while additive effects were found with the taxane docetaxel. Our results provide a strong rationale for the ongoing clinical study with APR-246 in combination with platinum-based therapy in patients with p53-mutant recurrent high-grade serous (HGS) ovarian cancer. More than 96% of these patients carry TP53 mutations. Combined treatment with APR-246 and platinum or other DNA-damaging drugs could allow dramatically improved therapy of a wide range of therapy refractory p53 mutant tumors.
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Mohell
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Alfredsson
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: Å
authors.initials: Å
authors.lastname: Fransson
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Uustalu
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Byström
authors.affiliation: 1] Clinical Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden [2] Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Gullbo
authors.affiliation: Department of Medicinal Chemistry, BMC, Uppsala University, Uppsala Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Hallberg
authors.affiliation: Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm, Sweden.
authors.forename: V J N
authors.initials: VJ
authors.lastname: Bykov
authors.affiliation: Aprea AB, Solna, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Björklund
authors.affiliation: Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm, Sweden.
authors.forename: K G
authors.initials: KG
authors.lastname: Wiman
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D002945:Cisplatin / Q000494:pharmacology*; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D000077143:Docetaxel; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000188:drug therapy; D017510:Protein Folding / Q000187:drug effects; D011812:Quinuclidines / Q000494:pharmacology*; D011897:Random Allocation; D043823:Taxoids / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
chemical_list: D000970:Antineoplastic Agents; D011812:Quinuclidines; D043823:Taxoids; D016159:Tumor Suppressor Protein p53; D003841:Deoxycytidine; D000077143:Docetaxel; D004317:Doxorubicin; D005978:Glutathione; D002945:Cisplatin; C533410:eprenetapopt; D000093542:Gemcitabine