Upregulation of heat shock protein 27 confers resistance to actinomycin D‐induced apoptosis in cancer cells

Abstract

Actinomycin D (Act D) is a general transcriptional inhibitor that is approved for the treatment of sarcomas, and Wilms, germ cell and trophoblastic tumors. Little is known about the molecular mechanisms that dictate the sensitivity of cancer cells to Act D. In this study, we investigated the effects of Act D on heat shock proteins (HSPs) and the expression and roles of HSP27 in Act D-induced cancer cell apoptosis. We show that Act D upregulates HSP27 and HSP70 expression in cancer cells, whereas it inhibits HSP90 expression. The upregulation of HSP27 by Act D is not attributable to changes in HSP27 transcription or HSP27 synthesis. HSP27 knockdown leads to an increase in Act D-induced caspase 3 and caspase 7 cleavage, and sensitizes rhabdosarcoma cells and breast cancer cells to Act D-induced apoptosis. We conclude that upregulation of HSP27 represents an adaptive response that compromises the anticancer activity of Act D.

In Vitro Cell Death Discrimination and Screening Method by Simple and Cost-Effective Viability Analysis

“…Prior to treatment (24 hrs after seeding the cells), cells were washed once with 100 µl 0% FBS DMEM (further referred to as ‘DMEM’). As established apoptosis inducers, the following drugs or treatments were used: RO 31-8220 (bisindoylmaleimidine IX, pan-PKC inhibitor, Selleckchem, Munich, Germany [33]), TBB (casein kinase II inhibitor, Sigma-Aldrich [34]), actinomycin D (DNA-dependent inhibitor of RNA synthesis, Abcam Biochemicals, Cambridge, United Kingdom [35]), H 2 O 2 (Sigma-Aldrich [36]) and a PDT treatment (Foscan ® , BioLitec Pharma, Dublin, Ireland [37]). Cells were incubated with eleven different concentrations (serial 1+1 dilution) of RO 31-8220 (starting at 10 µM), TBB (40 µM), Act-D (20 µM), or H 2 O 2 (40 mM) in DMEM.…”

HSP27 is Commonly Expressed in Cervical Intraepithelial Lesions of Brazilian Women

“…to its protective role during heat shock and other forms of environmental and pathophysiological stress, reveals a wide spectrum of functions including regulation of cell growth and differentiation (Adly et al, 2006) and of cytoskeletal dynamics (Hirano et al, 2004), signal transduction and protection against apoptosis induced by different agents (Ma et al, 2013).…”

“…Hsp27 are abundantly expressed in malignant cells, and have been accused of participating in oncogenesis or chemotherapy resistence (Ma et al, 2013), presumably due to its capacity to disable apoptosis. In breast, gastric and endometrial cancer, the high expression of Hsp27 has been associated with metastasis, poor prognosis and resistance to chemotherapy or radiation (Ma et al, 2013;Svensson et al, 2013).…”

“…In breast, gastric and endometrial cancer, the high expression of Hsp27 has been associated with metastasis, poor prognosis and resistance to chemotherapy or radiation (Ma et al, 2013;Svensson et al, 2013).…”

Small Heat Shock Proteins and Fibrosis

“…sHSPs take part in several molecular mechanisms of cancerous cells, including proliferation (Hayashi et al 2012 ), invasion (Lemieux et al 1997 ), angiogenesis (Thuringer et al 2013 ) and metastasis formation (Pavan et al 2014 ;van de Schootbrugge et al 2013 ;Malin et al 2014 ). In several reports, sHSPs appeared benefi cial for cancerous cells and thereby deleterious for patients affected by a wide range of cancer types (Rappa et al 2012 ;Ma et al 2013 ;Ruan et al 2011 ;Ivanov et al 2008 ). sHSP inhibition thus appears to be of great interest in order to improve the effi ciency of chemotherapy and disease outcome (Jakubowicz-Gil et al 2013 ;Gibert et al 2013 ).…”