TY - JOUR
T1 - RAD50 targeting impairs DNA damage response and sensitizes human breast cancer cells to cisplatin therapy
AU - Flores-Pérez, Ali
AU - Rafaelli, Lourdes E.
AU - Ramírez-Torres, Nayeli
AU - Aréchaga-Ocampo, Elena
AU - Frías, Sara
AU - Sánchez, Silvia
AU - Marchat, Laurence A.
AU - Hidalgo-Miranda, Alfredo
AU - Quintanar-Jurado, Valeria
AU - Rodríguez-Cuevas, Sergio
AU - Bautista-Piña, Verónica
AU - Carlos-Reyes, Ángeles
AU - López-Camarillo, César
N1 - Funding Information:
This work was supported by CONACyT FONSEC SALUD 112454 and 115306 grants. We also acknowledge the Instituto de Ciencia y Tecnología del Distrito Federal, Mexico (ICyTDF/328/2011 and ICYTDF/179/2011). A.F.P. was supported by ICyTDF (SRI/PB/64/2011) fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
PY - 2014/6
Y1 - 2014/6
N2 - In tumor cells the effectiveness of anti-neoplastic agents that cause cell death by induction of DNA damage is influenced by DNA repair activity. RAD50 protein plays key roles in DNA double strand breaks repair (DSBs), which is crucial to safeguard genome integrity and sustain tumor suppression. However, its role as a potential therapeutic target has not been addressed in breast cancer. Our aim in the present study was to analyze the expression of RAD50 protein in breast tumors, and evaluate the effects of RAD50-targeted inhibition on the cytotoxicity exerted by cisplatin and anthracycline and taxane-based therapies in breast cancer cells. Immunohistochemistry assays on tissue microarrays indicate that the strong staining intensity of RAD50 was reduced in 14% of breast carcinomas in comparison with normal tissues. Remarkably, RAD50 silencing by RNA interference significantly enhanced the cytotoxicity of cisplatin. Combinations of cisplatin with doxorubicin and paclitaxel drugs induced synergistic effects in early cell death of RAD50-deficient MCF-7, SKBR3, and T47D breast cancer cells. Furthermore, we found an increase in the number of DSBs, and delayed phosphorylation of histone H2AX after cisplatin treatment in RAD50-silenced cells. These cellular events were associated to a dramatical increase in the frequency of chromosomal aberrations and a decrease of cell number in metaphase. In conclusion, our data showed that RAD50 abrogation impairs DNA damage response and sensitizes breast cancer cells to cisplatin-combined therapies. We propose that the development and use of inhibitors to manipulate RAD50 levels might represent a promising strategy to sensitize breast cancer cells to DNA damaging agents.
AB - In tumor cells the effectiveness of anti-neoplastic agents that cause cell death by induction of DNA damage is influenced by DNA repair activity. RAD50 protein plays key roles in DNA double strand breaks repair (DSBs), which is crucial to safeguard genome integrity and sustain tumor suppression. However, its role as a potential therapeutic target has not been addressed in breast cancer. Our aim in the present study was to analyze the expression of RAD50 protein in breast tumors, and evaluate the effects of RAD50-targeted inhibition on the cytotoxicity exerted by cisplatin and anthracycline and taxane-based therapies in breast cancer cells. Immunohistochemistry assays on tissue microarrays indicate that the strong staining intensity of RAD50 was reduced in 14% of breast carcinomas in comparison with normal tissues. Remarkably, RAD50 silencing by RNA interference significantly enhanced the cytotoxicity of cisplatin. Combinations of cisplatin with doxorubicin and paclitaxel drugs induced synergistic effects in early cell death of RAD50-deficient MCF-7, SKBR3, and T47D breast cancer cells. Furthermore, we found an increase in the number of DSBs, and delayed phosphorylation of histone H2AX after cisplatin treatment in RAD50-silenced cells. These cellular events were associated to a dramatical increase in the frequency of chromosomal aberrations and a decrease of cell number in metaphase. In conclusion, our data showed that RAD50 abrogation impairs DNA damage response and sensitizes breast cancer cells to cisplatin-combined therapies. We propose that the development and use of inhibitors to manipulate RAD50 levels might represent a promising strategy to sensitize breast cancer cells to DNA damaging agents.
KW - Breast cancer
KW - Chemosensitization
KW - Chromosomal aberrations
KW - Cisplatin
KW - DNA damage
KW - Doxorubicin
KW - Histone H2AX
KW - Paclitaxel
KW - RAD50 targeting
UR - http://www.scopus.com/inward/record.url?scp=84901719361&partnerID=8YFLogxK
U2 - 10.4161/cbt.28551
DO - 10.4161/cbt.28551
M3 - Artículo
C2 - 24642965
SN - 1538-4047
VL - 15
SP - 777
EP - 788
JO - Cancer Biology and Therapy
JF - Cancer Biology and Therapy
IS - 6
ER -