Abstract
Background: Breast and ovarian tumors with pathogenic variants in BRCA1 or BRCA2
genes are more sensitive to poly (ADP-ribose) polymerase inhibitors (PARPi) treatment than wildtype
tumors. Pathogenic variants in non-BRCA1/2 homologous recombination repair genes (HRR) also
concede sensitivity to PARPi treatment. RAD50 participates in the Mre11-RAD50-Nbn (MRN)
complex of the HRR pathway and plays an important role in DNA repair.
Objective: The objective of this study is to evaluate whether RAD50 protein deficiency modulates the
PARPi response in breast cancer cell lines.
Methods: T47D breast cancer cell line was modified using small interfering RNA and CRISPR/Cas9
technology, to knockout the RAD50 gene. PARPi response (niraparib, olaparib and rucaparib alone or
in combination with carboplatin), in T47D and T47D-edited clones, was evaluated by cell viability,
cell cycle, apoptosis and protein expression analyses.
Results: Treatment with niraparib and carboplatin exerted a synergistic effect on T47D-RAD50 deficient
cells and an antagonistic effect on T47D cells parental. Cell cycle analysis demonstrated an increase
in the G2/M population in cells treated with niraparib or rucaparib alone or in combination with
carboplatin. T47D-RAD50 deficient cells treated with rucaparib and carboplatin exhibited twofold
levels in late apoptosis, also showing differences in PARP activation. All T47D RAD50 deficient
clones treated with niraparib or rucaparib combined with carboplatin, or rucaparib alone showed increased
levels of H2AX phosphorylation.
Conclusions: T47D RAD50 deficient cells treated with PARP inhibitors alone or in combination with
carboplatin showed cell cycle arrest in the G2/M phase, leading to death by apoptosis. Thus, RAD50
deficiency may be a good biomarker for predicting PARPi response.
Keywords:
PARP inhibitors, synthetic lethality, DNA repair, homologous recombination, breast cancer, target therapy.
Graphical Abstract
[3]
Miki, Y.; Swensen, J.; Shattuck-Eidens, D.; Futreal, P.A.; Harshman, K.; Tavtigian, S.; Liu, Q.; Cochran, C.; Bennett, L.M.; Ding, W.; Bell, R.; Rosenthal, J.; Hussey, C.; Tran, T.; McClure, M.; Frye, C.; Hattier, T.; Phelps, R.; Haugen-Strano, A.; Katcher, H.; Yakumo, K.; Gholami, Z.; Shaffer, D.; Stone, S.; Bayer, S.; Wray, C.; Bogden, R.; Dayananth, P.; Ward, J.; Tonin, P.; Narod, S.; Bristow, P.K.; Norris, F.H.; Helvering, L.; Morrison, P.; Rosteck, P.; Lai, M.; Barrett, J.C.; Lewis, C.; Neuhausen, S.; Cannon-Albright, L.; Goldgar, D.; Wiseman, R.; Kamb, A.; Skolnick, M.H. A strong candidate for the breast and ovarian cancer susceptibility gene BRCA1.
Science, 1994,
266(5182), 66-71.
[
http://dx.doi.org/10.1126/science.7545954] [PMID:
7545954]
[5]
Tavtigian, S.V.; Simard, J.; Rommens, J.; Couch, F.; Shattuck-Eidens, D.; Neuhausen, S.; Merajver, S.; Thorlacius, S.; Offit, K.; Stoppa-Lyonnet, D.; Belanger, C.; Bell, R.; Berry, S.; Bogden, R.; Chen, Q.; Davis, T.; Dumont, M.; Frye, C.; Hattier, T.; Jammulapati, S.; Janecki, T.; Jiang, P.; Kehrer, R.; Leblanc, J.F.; Mitchell, J.T.; McArthur-Morrison, J.; Nguyen, K.; Peng, Y.; Samson, C.; Schroeder, M.; Snyder, S.C.; Steele, L.; Stringfellow, M.; Stroup, C.; Swedlund, B.; Swense, J.; Teng, D.; Thomas, A.; Tran, T.; Tranchant, M.; Weaver-Feldhaus, J.; Wong, A.K.C.; Shizuya, H.; Eyfjord, J.E.; Cannon-Albright, L.; Tranchant, M.; Labrie, F.; Skolnick, M.H.; Weber, B.; Kamb, A.; Goldgar, D.E. The complete BRCA2 gene and mutations in chromosome 13q-linked kindreds.
Nat. Genet., 1996,
12(3), 333-337.
[
http://dx.doi.org/10.1038/ng0396-333] [PMID:
8589730]
[6]
Kuchenbaecker, K.B.; Hopper, J.L.; Barnes, D.R.; Phillips, K.A.; Mooij, T.M.; Roos-Blom, M.J.; Jervis, S.; van Leeuwen, F.E.; Milne, R.L.; Andrieu, N.; Goldgar, D.E.; Terry, M.B.; Rookus, M.A.; Easton, D.F.; Antoniou, A.C.; McGuffog, L.; Evans, D.G.; Barrowdale, D.; Frost, D.; Adlard, J.; Ong, K.; Izatt, L.; Tischkowitz, M.; Eeles, R.; Davidson, R.; Hodgson, S.; Ellis, S.; Nogues, C.; Lasset, C.; Stoppa-Lyonnet, D.; Fricker, J.P.; Faivre, L.; Berthet, P.; Hooning, M.J.; van der Kolk, L.E.; Kets, C.M.; Adank, M.A.; John, E.M.; Chung, W.K.; Andrulis, I.L.; Southey, M.; Daly, M.B.; Buys, S.S.; Osorio, A.; Engel, C.; Kast, K.; Schmutzler, R.K.; Caldes, T.; Jakubowska, A.; Simard, J.; Friedlander, M.L.; McLachlan, S.A.; Machackova, E.; Foretova, L.; Tan, Y.Y.; Singer, C.F.; Olah, E.; Gerdes, A.M.; Arver, B.; Olsson, H. Risks of breast, ovarian, and contralateral breast cancer for BRCA1 and BRCA2 Mutation Carriers.
JAMA, 2017,
317(23), 2402-2416.
[
http://dx.doi.org/10.1001/jama.2017.7112] [PMID:
28632866]