Molecular characterization of irinotecan (SN-38) resistant human breast cancer cell lines

TY - JOUR

T1 - Molecular characterization of irinotecan (SN-38) resistant human breast cancer cell lines

AU - Jandu, Haatisha

AU - Aluzaité, Kristina

AU - Fogh, Louise

AU - Thrane, Sebastian Wingaard

AU - Noer, Julie B

AU - Proszek, Joanna

AU - Nguyen Do, Khoa

AU - Hansen, Stine Ninel

AU - Damsgaard-Hansen, Britt

AU - Nielsen, Signe Lykke

AU - Stougaard, Magnus

AU - Knudsen, Birgitta R.

AU - Moreira, José

AU - Hamerlik, Petra

AU - Gajjar, Madhavsai

AU - Smid, Marcel

AU - Martens, John

AU - Foekens, John

AU - Pommier, Yves

AU - Brünner, Nils

AU - Rasmussen, Anne-Sofie Schrohl

AU - Stenvang, Jan

PY - 2016/1/22

Y1 - 2016/1/22

N2 - BACKGROUND: Studies in taxane and/or anthracycline refractory metastatic breast cancer (mBC) patients have shown approximately 30 % response rates to irinotecan. Hence, a significant number of patients will experience irinotecan-induced side effects without obtaining any benefit. The aim of this study was to lay the groundwork for development of predictive biomarkers for irinotecan treatment in BC.METHODS: We established BC cell lines with acquired or de novo resistance to SN-38, by exposing the human BC cell lines MCF-7 and MDA-MB-231 to either stepwise increasing concentrations over 6 months or an initial high dose of SN-38 (the active metabolite of irinotecan), respectively. The resistant cell lines were analyzed for cross-resistance to other anti-cancer drugs, global gene expression, growth rates, TOP1 and TOP2A gene copy numbers and protein expression, and inhibition of the breast cancer resistance protein (ABCG2/BCRP) drug efflux pump.RESULTS: We found that the resistant cell lines showed 7-100 fold increased resistance to SN-38 but remained sensitive to docetaxel and the non-camptothecin Top1 inhibitor LMP400. The resistant cell lines were characterized by Top1 down-regulation, changed isoelectric points of Top1 and reduced growth rates. The gene and protein expression of ABCG2/BCRP was up-regulated in the resistant sub-lines and functional assays revealed BCRP as a key mediator of SN-38 resistance.CONCLUSIONS: Based on our preclinical results, we suggest analyzing the predictive value of the BCRP in breast cancer patients scheduled for irinotecan treatment. Moreover, LMP400 should be tested in a clinical setting in breast cancer patients with resistance to irinotecan.

AB - BACKGROUND: Studies in taxane and/or anthracycline refractory metastatic breast cancer (mBC) patients have shown approximately 30 % response rates to irinotecan. Hence, a significant number of patients will experience irinotecan-induced side effects without obtaining any benefit. The aim of this study was to lay the groundwork for development of predictive biomarkers for irinotecan treatment in BC.METHODS: We established BC cell lines with acquired or de novo resistance to SN-38, by exposing the human BC cell lines MCF-7 and MDA-MB-231 to either stepwise increasing concentrations over 6 months or an initial high dose of SN-38 (the active metabolite of irinotecan), respectively. The resistant cell lines were analyzed for cross-resistance to other anti-cancer drugs, global gene expression, growth rates, TOP1 and TOP2A gene copy numbers and protein expression, and inhibition of the breast cancer resistance protein (ABCG2/BCRP) drug efflux pump.RESULTS: We found that the resistant cell lines showed 7-100 fold increased resistance to SN-38 but remained sensitive to docetaxel and the non-camptothecin Top1 inhibitor LMP400. The resistant cell lines were characterized by Top1 down-regulation, changed isoelectric points of Top1 and reduced growth rates. The gene and protein expression of ABCG2/BCRP was up-regulated in the resistant sub-lines and functional assays revealed BCRP as a key mediator of SN-38 resistance.CONCLUSIONS: Based on our preclinical results, we suggest analyzing the predictive value of the BCRP in breast cancer patients scheduled for irinotecan treatment. Moreover, LMP400 should be tested in a clinical setting in breast cancer patients with resistance to irinotecan.

KW - Faculty of Social Sciences

KW - Breast cancer

KW - Topoisomerase I

KW - Irinotecan

KW - SN-38

KW - Resistance

KW - ABCG2/BCRP

U2 - 10.1186/s12885-016-2071-1

DO - 10.1186/s12885-016-2071-1

M3 - Journal article

C2 - 26801902

SN - 1471-2407

VL - 16

JO - B M C Cancer

JF - B M C Cancer

M1 - 34

ER -