Supplementary MaterialsSupplementary Figure 1: Resveratrol induces the formation of AVOs in breast cancer cells
March 8, 2021
Supplementary MaterialsSupplementary Figure 1: Resveratrol induces the formation of AVOs in breast cancer cells. investigations in breast cancer patients. However, the molecular mechanism of action of SAHA in breast cancer cells remains unclear. In this study, we found that SAHA is equally effective in targeting cells of different breast cancer subtypes and tamoxifen sensitivity. Importantly, we found that down-regulation of survivin plays an important role in SAHA-induced autophagy and cell viability reduction in human breast cancer cells. SAHA decreased survivin and XIAP gene transcription, induced survivin protein acetylation and early nuclear translocation in MCF7 and MDA-MB-231 breast cancer cells. It also reduced survivin and XIAP protein stability in part through modulating the expression and activation of the 26S proteasome and heat-shock proteins 90. Interestingly, targeting HDAC6 and HDAC3, but not additional HDAC isoforms, by siRNA/pharmacological Pomalidomide (CC-4047) inhibitors mimicked the consequences of SAHA in modulating the acetylation, manifestation, and nuclear translocation of survivin and induced autophagy in MCF7 and MDA-MB-231 cancer cells. Targeting HDAC3 also mimicked the effect of SAHA in up-regulating the expression and activity of proteasome, which might lead to the reduced protein stability of survivin in breast cancer cells. In conclusion, this study provides new insights into SAHA’s molecular mechanism of actions in breast cancer cells. Our findings emphasize the complexity of Pomalidomide (CC-4047) the regulatory roles in different HDAC isoforms and potentially assist in predicting the mechanism of novel HDAC inhibitors in targeted or combinational therapies in the future. identifier: “type”:”clinical-trial”,”attrs”:”text”:”NCT00416130″,”term_id”:”NCT00416130″NCT00416130, “type”:”clinical-trial”,”attrs”:”text”:”NCT00368875″,”term_id”:”NCT00368875″NCT00368875, “type”:”clinical-trial”,”attrs”:”text”:”NCT01720602″,”term_id”:”NCT01720602″NCT01720602) in male/female patients with breast cancer. Surprisingly, although several studies have shown that SAHA induces autophagy, apoptosis, and exhibits potent anti-proliferative activity in cancer cells, the exact mechanisms by which SAHA induces these effects have not been fully comprehended (Butler et al., 2002; Lee et al., 2012). Survivin is a well-known member of the inhibitor-of-apoptosis proteins (IAPs) family. It regulates mitosis and inhibits both caspase-dependent and -impartial apoptosis in cancer cells (Li et al., 1998; Tamm et al., 1998; Cheung et al., 2010; Coumar et al., 2013). Interestingly, our previous study revealed that even though survivin is an inhibitor of apoptosis, targeting survivin by small molecule inhibitor or by siRNA induces autophagy and autophagic cell death in breast cancer cells regardless of the endogenous expression of p53 and caspase-3 (Cheng et al., 2015). However, survivin is usually traditionally classified as an apoptosis inhibitor; therefore, the role of survivin in SAHA-induced autophagy and autophagic cell death in cancer cells has seldom been investigated. In Rabbit Polyclonal to PITX1 this study, we found that SAHA down-regulates survivin expression at both transcriptional and post-transcriptional levels in part through HDAC2, HDAC3, and HDAC6 inhibitions. In addition, we found Pomalidomide (CC-4047) that down-regulation of survivin plays an important role in regulating SAHA induced autophagy and cell viability reduction in breast cancer cells. Materials and methods Cell lines and cell culture conditions Human breast adenocarcinoma cell lines MCF7 (p53 wild-type), MDA-MB-231 (p53 mutant), and SK-BR-3 (p53 mutant) were originally obtained from ATCC (Table ?(Table1).1). Briefly, MCF7 cells were cultured in -MEM made up of 5% fetal bovine serum (FBS), penicillin/streptomycin/glutamine (PSG), and insulin transferrin selenium [ITS (Roche, cat# 11074547001)]. MDA-MB-231 cells were cultured in RPMI made up of 10% FBS and PSG. SK-BR-3 cells were cultured in DMEM made up of 10% FBS and PSG. All cell lines were incubated at 37C in a humidified incubator made up of 5% CO2 in air and were shown to be mycoplasma free. A series of MCF7-derived ER+/tamoxifen-resistant breast cancer cell lines (TamC3 and TamR8) were also used in this study. The cellular and molecular phenotypes of these tamoxifen-resistant breast malignancy cell lines have already been characterized in a previous study (Leung et al., 2010). TamR8 breast cancer cells were cultured in -MEM made up of 5% fetal.