Functional restoration of BRCA2 protein by secondary BRCA2 mutations in BRCA2-mutated ovarian carcinoma.
Acquired platinum resistance is a serious problem in the treatment of ovarian carcinomas. However, the mechanism of the drug resistance has not been elucidated. Here, we show functional significance of restoration of BRCA2 protein by secondary BRCA2 mutations in acquired drug resistance of BRCA2-mutated ovarian carcinoma. Three ovarian cancer cell lines (PEO1, PEO4, and PEO6) were derived from a BRCA2 mutation [5193C>G (Y1655X)] carrier with ovarian carcinoma with acquired cisplatin resistance and a secondary BRCA2 mutation [5193C>T (Y1655Y)] that canceled the inherited mutation. PEO1 was BRCA2 deficient and sensitive to cisplatin and a poly(ADP-ribose) polymerase inhibitor, AG14361, whereas PEO4 was resistant. PEO4 and PEO6, derived from ascites at the time of relapse with cisplatin resistance, had the secondary mutation and were BRCA2 proficient. In vitro cisplatin/AG14361 selection of PEO1 led to restoration of BRCA2 due to another secondary BRCA2 mutation. BRCA2 depletion sensitized BRCA2-restored PEO1 clones and PEO4 to cisplatin/AG14361. Thus, restoration of BRCA2 due to secondary BRCA2 mutation is involved in acquired drug resistance of BRCA2-mutated ovarian carcinoma.
Sakai
Wataru
W
Division of Human Biology, Fred Hutchinson Cancer Research Center, Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington 98109-1024, USA.
Swisher
Elizabeth M
EM
Jacquemont
Céline
C
Chandramohan
Kurapaty Venkatapoorna
KV
Couch
Fergus J
FJ
Langdon
Simon P
SP
Wurz
Kaitlyn
K
Higgins
Jake
J
Villegas
Emily
E
Taniguchi
Toshiyasu
T
D051017:Apoptosis Regulatory Proteins; D024682:BRCA2 Protein / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002945:Cisplatin / Q000494:pharmacology / Q000627:therapeutic use; D004252:DNA Mutational Analysis; D019008:Drug Resistance, Neoplasm / Q000235:genetics* / Q000502:physiology; D005260:Female; D006801:Humans; D009154:Mutation / Q000502:physiology; D016366:Open Reading Frames / Q000187:drug effects / Q000235:genetics; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D051017:Apoptosis Regulatory Proteins; C118024:BLID protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D034741:RNA, Small Interfering; D002945:Cisplatin