Probenecid as a sensitizer of bisphosphonate-mediated effects in breast cancer cells

Molecular Cancer

Research

Tilman D Rachner¹  Lorenz C Hofbauer¹  Regina Ebert²  Birgit Mentrup²  Sabine Zeck²  Franz Jakob²  Stephanie Graser²  Jutta Meissner-Weigl²  Sofia Coimbra de Sousa³  Jorma Määttä³  Seppo Auriola³ 

[1] Division of Endocrinology, Diabetes and Bone Metabolism, Technical University of Dresden, Fetscherstrasse 74, 01307, Dresden, Germany;Orthopedic Center for Musculoskeletal Research, University of Würzburg, Brettreichstrasse 11, 97074, Würzburg, Germany;School of Pharmacy, University of Eastern Finland, POB 1627, Yliopistonranta 1C, 70211, Kuopio, Finland;

关键词: Bisphosphonates;    Caspase 3/7 activity;    Cell viability;    Probenecid;    Novobiocin;    Breast cancer cells;   

DOI  :  10.1186/1476-4598-13-265

 received in 2014-01-29, accepted in 2014-11-27,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundAnti-resorptive bisphosphonates (BP) are used for the treatment of osteoporosis and bone metastases. Clinical studies indicated a benefit in survival and tumor relapse in subpopulations of breast cancer patients receiving zoledronic acid, thus stimulating the debate about its anti-tumor activity. Amino-bisphosphonates in nM concentrations inhibit farnesyl pyrophosphate synthase leading to accumulation of isopentenyl pyrophosphate (IPP) and the ATP/pyrophosphate adduct ApppI, which induces apoptosis in osteoclasts. For anti-tumor effects μM concentrations are needed and a sensitizer for bisphosphonate effects would be beneficial in clinical anti-tumor applications. We hypothesized that enhancing intracellular pyrophosphate accumulation via inhibition of probenecid-sensitive channels and transporters would sensitize tumor cells for bisphosphonates anti-tumor efficacy.MethodMDA-MB-231, T47D and MCF-7 breast cancer cells were treated with BP (zoledronic acid, risedronate, ibandronate, alendronate) and the pyrophosphate channel inhibitors probenecid and novobiocin. We determined cell viability and caspase 3/7 activity (apoptosis), accumulation of IPP and ApppI, expression of ANKH, PANX1, ABCC1, SLC22A11, and the zoledronic acid target gene and tumor-suppressor KLF2.ResultsTreatment of MDA-MB-231 with BP induced caspase 3/7 activity, with zoledronic acid being the most effective. In MCF-7 and T47D either BP markedly suppressed cell viability with only minor effects on apoptosis. Co-treatment with probenecid enhanced BP effects on cell viability, IPP/ApppI accumulation as measurable in MCF-7 and T47D cells, caspase 3/7 activity and target gene expression. Novobiocin co-treatment of MDA-MB-231 yielded identical results on viability and apoptosis compared to probenecid, rendering SLC22A family members as candidate modulators of BP effects, whereas no such evidence was found for ANKH, ABCC1 and PANX1.ConclusionsIn summary, we demonstrate effects of various bisphosphonates on caspase 3/7 activity, cell viability and expression of tumor suppressor genes in breast cancer cells. Blocking probenecid and novobiocin-sensitive channels and transporters enhances BP anti-tumor effects and renders SLC22A family members as good candidates as BP modulators. Further studies will have to unravel if treatment with such BP-sensitizers translates into preclinical and clinical efficacy.

【 授权许可】

Unknown   
© Ebert et al.; licensee BioMed Central. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.