Triple-negative breast cancer (TNBC) is usually a highly aggressive phenotype that is resistant to standard therapy. resistant to conventional treatment. Introduction Of all cancers, breast malignancy has the highest incidence and mortality rate in Europe according to data from 2012 [1]. Approximately 15C20% of breast cancer cases are diagnosed as triple-negative breast cancer (TNBC), a highly aggressive clinical phenotype characterized by a lack of human epidermal growth factor receptor-2 (HER-2) overexpression, as well as a lack of estrogen and progesterone receptor expression [2, 3]. The overall survival rate of TNBC is usually less than 30% at five years after diagnosis due to its unique histological and molecular features, as well as the ineffectiveness of treatments and adjuvant hormone therapies [4]. TNBC represents a hostile histological subtype of breast malignancy with limited medication options; therefore the development of option targeted therapies is important to improve the overall survival rates of TNBC patients [5]. The p53 gene, i.e. the rebel angel according to Walerych Rabbit polyclonal to ZNF346 [6], is the most frequently mutated gene in the pathology of breast malignancy tumors [7]. Mutant p53 has an oncogenic role in tumorigenesis and metastasis [6]. The p53 protein is usually overexpressed in TNBC and is involved in the cellular stress response, repair and survival of damaged cells, and cell cycle arrest, [8], as well as resistance to apoptosis and inhibition of autophagy [6, 9, 10]. Increasing evidence shows that the p53 mutation is related to the activation of invasion and metastasis, as well as to inhibition of angiogenesis [6, 11], suggesting therapies involving p53 siRNA may target multiple molecular mechanisms as well as apoptosis [12]. Epigallocatechingallate (EGCG) is the most abundant compound found in green tea, and many research studies, in the last decade, have focused on its biological activities and mechanisms of action in cancer. EGCG inhibits several critical proteins that are involved in malignancy cell progression [13], migration [14], and induction of apoptosis through the production of reactive oxygen species, induction of cell cycle progression, and inhibition of the NF-B cell-signaling pathway [15]. To identify the physiological responsiveness of EGCG in tumor breast malignancy cells, elucidating the molecular mechanisms and the molecular targets that trigger or inhibit a specific signaling pathway is essential [16]. In the present study, we investigated the response of breast malignancy cells to multiple therapeutic targets by silencing mutant p53 through RNA interference mechanisms and investigating the inhibitory effect of EGCG on tumor cell survival, growth, and migration, and thereby the mechanism of treatment resistance using dual targeted therapy. Materials and Methods Cell culture We purchased the TNBC cell line Hs578T, which expresses a mutant p53 gene, from the American Type Culture Collection for all those experiments. Cells were maintained in high-glucose DMEM made up of 10% fetal bovine serum, 2 mM L-glutamine, and 2 mM penicillin-streptomycin (all from Sigma-Aldrich, Germany) supplemented with 0.1% insulin. Cells were incubated in 5% CO2 incubator at 37C. siRNA transfection For mRNA analysis, cells were plated in 6-well plates at a seeding density of 5 105 cells and simultaneously transfected, alone or in LY2228820 combination LY2228820 with 40 nmol p53-siRNA (Ambion, TX, USA) and EGCG (Sigma-Aldrich, St. Louis, MO, USA). The siPORT NeoFX Transfection Agent (Invitrogenby Life Technologies) being used for siRNA delivery, and cells were cultured in Opti-MEM I (Gibco-Invitrogen, Paisley, UK) reduced serum medium. Cells were harvested in LY2228820 TriReagent (Sigma-Aldrich, St. Louis, MO, USA) 24 hours after transfection and prepared for total RNA extraction. For autophagy and angiogenesis assays, we used 96-well plates and reduced the reagent volumes by one-tenth. All experiments being performed in triplicate. RNA extraction, qRT-PCR array and data.