Asian Pacific Journal of Cancer Prevention, Vol 14, 2013 891 DOI:http://dx.doi.org/10.7314/APJCP.2013.14.2.891 Effect of Botulinum Toxin A on Proliferation and Apoptosis in T47D Breast Cancer Cells Asian Pacific J Cancer Prev, 14 (2), 891-894 Introduction Breast cancer in women is a major health problem worldwide, with approximately 1.3 million women was estimated to be diagnosed with breast cancer in 2008 (Smith et al., 2012; Bray et al., 2013). Breast cancer is a heterogeneous disease in terms of gene expression, morphology, clinical course, and response to treatment. Therapeutic options for this breast cancer include surgery, adjuvant chemotherapy, radiotherapy, hormonal therapy or targeted therapy (Kim et al., 2012; Lee et al., 2012; Sendur et al., 2012; Truin et al., 2012; Zhou et al., 2012; Edge, 2013). The most widely known action of botulinum toxin A (BtxA) is its relaxing effect on skeletal muscles. BtxA is therefore widely used for the symptomatic relief of spasticity, and other movement disorders. Recently there has been great interest in the use of botulinum toxin type A for prostate cancer. This interest stems from the fact that BtxA inhibits the growth of LNCaP human prostate cancer cells in vitro and in vivo and induces apoptosis in a dose-dependent manner (Mazo et al., 2008; Karsenty et al., 2009; Proietti et al., 2012). Moreover, BtxA has been shown for up-regulate 167 genes and down-regulate 60 genes relevant to focal adhesion, cell adhesion molecules, adherents and gap junction related pathways in carcinoma cell lines (Thirunavukkarasusx et al., 2011; Gorgal et al., 2012; Nam et al., 2012; Tegenge et al., 2012). The 1 Department of Research Support, Instituto Nacional de Rehabilitación, 3 Molecular Oncology and Oxidative Stress Laboratory, Escuela Superior de Medicina, Instituto Politécnico Nacional, México City, 2 Vice-rectory of Research and Postgraduate Studies, Benémerita Universidad Autónoma de Puebla, 4 Laboratory of Cellular Biology, Centro de Investigación Biomédica de Oriente, Instituto Mexicano del Seguro Social, Puebla, México *For correspondence: manaya19@yahoo.com.mx Abstract The present study was performed to assess the activity of the botulinum toxin A on breast cancer cells. The T47D cell line was exposed to diverse concentrations of the botulinum toxin A and cell viability and apoptosis were estimated using MTT and propidium iodine/annexin V methods, respectively. Botulinum toxin A exerted greater cytotoxic activity in T47D cells in comparison with MCF10A normal cells; this appeared to be via apoptotic processes caspase-3 and -7. In conclusion, botulinum toxin A induces caspase-3 and -7 dependent apoptotic processes in the T47D breast cancer cell line. Keywords: Breast cancer - botulinum toxin A - apoptosis - caspases RESEARCH ARTICLE Effect of Botulinum Toxin A on Proliferation and Apoptosis in the T47D Breast Cancer Cell Line Cindy Bandala 1 , Jose Luis Martin Perez-Santos 2 , Eleazar Lara-Padilla 3 , Ma. Guadalupe Delgado Lopez 4 *, Maricruz Anaya-Ruiz 4 * objective of this study was to test the activity of BtxA against breast cancer cell proliferation underlying this phenomenon as a trial for developing a novel functional anticancer drug. Thus, we investigated the effect of BtxA on cell proliferation and apoptosis using T47D human breast cancer cell line. The results showed that treatment allowed for equivalent loss of cell viability in cancerous cells when compared to a high dose of BtxA. Materials and Methods Cell culture MCF10A cells (CRL-10317, ATCC), a spontaneously immortalized but non-tumoral cell line, were cultured in DMEM/F-12 medium (PAA, Carlsbad, CA) supplemented with 10 µg/mL of human insulin, 20 ng/mL of epidermal growth factor, 0.5 µg/mL of hydrocortisone (Sigma, St. Louis, MO), 5% horse serum (Invitrogen), 100 U/mL of penicillin and 100 µg/mL of streptomycin (PAA). T47D cells (HTB-133, ATCC), a triple positive breast cancer cell line, were grown in RPMI-1640 medium (Sigma, St. Louis, MO), supplemented with 10% fetal bovine serum (FBS), 100 U/mL of penicillin, and 100 µg/mL of streptomycin. Botulinum toxin A Botox ® , injectable therapeutic agent, contains 4.8 ng of BtxA per vial of 100 units /Allergan, Inc., Markham,