Autophagic cell death, polyploidy and senescence induced in breast tumor cells by the substituted pyrrole JG-03-14, a novel microtubule poison

Abstract

JG-03-14, a substituted pyrrole that inhibits microtubule polymerization, was screened against MCF-7 (p53 wild type), MDA-MB 231 (p53 mutant), MCF-7/caspase 3 and MCF-7/ADR (multidrug resistant) breast tumor cell lines. Cell viability and growth inhibition were assessed by the crystal violet dye assay. Apoptosis was evaluated by the TUNEL assay, cell cycle distribution by flow cytometry, autophagy by acridine orange staining of vesicle formation, and senescence based on β-galactosidase staining and cell morphology. Our studies indicate that exposure to JG-03-14, at a concentration of 500 nM, induces time dependent cell death in the MCF-7 and MDA-MB 231 cell lines. In MCF-7 cells, a residual surviving cell population was found to be senescent; in contrast, there was no surviving senescent population in treated MDA-MB 231 cells. No proliferative recovery was detected over a period of 15 days post-treatment in either cell line. Both the TUNEL assay and FLOW cytometry indicated a relatively limited degree of apoptosis (< 10%) in response to drug treatment in MCF-7 cells with more extensive apoptosis (but < 20%) in MDA-MB231 cells; acidic vacuole formation indicative of autophagic cell death was relatively extensive in both MCF-7 and MDA-MB231 cells. In addition, JG-03-14 induced the formation of a large hyperdiploid cell population in MDA-MB231 cells. JG-03-14 also demonstrated pronounced anti-proliferative activity in MCF-7/caspase 3 cells and in the MCF-7/ADR cell line. The observation that JG-03-14 promotes autophagic cell death and also retains activity in tumor cells expressing the multidrug resistance pump indicates that novel microtubule poisons of the substituted pyrroles class may hold promise in the treatment of breast cancer.

Sildenafil and Phosphofiesterase-5 Inhibitors to Reduce Cardiotoxicity and Enhance the Response of Breast Tumors to Doxrubicin

“…Adriamycin also has the capacity to promote senescence (7) in breast tumor cells and our current studies indicate that another mode of cell death, known as autophagy (8) (Figure 3) is also evident in breast tumor cells treated with adriamycin. Studies are currently in progress to determine the impact of sildenafil on both senescence and autophagic responses to adriamycin in the breast tumor cell.…”

Docking and hydropathic scoring of polysubstituted pyrrole compounds with antitubulin activity

“…Cellular studies with JG-03-14 further support the contention that these compounds function as microtubule poisons [18]. In addition, JG-03-14 was found to have the capacity to promote both autophagic and apoptotic cell death, albeit in different cell lines, while retaining activity in tumor cells expressing the multidrug resistant pump P-glycoprotein [18,24]. Because the development of additional synthetic or semi-synthetic pyrrole derivatives in this class is facilitated with their relatively facile syntheses, including modification of the molecule by adding and removing functional groups [19], we have both a rather extensive collection of molecules in-hand (Scheme 1) for building predictive molecular models and the potential for rational design and synthesis of many others.…”

“…Results from a number of assays have previously appeared regarding the antiproliferative and cytotoxic activities of the lead compound JG-03-14 [18,19,24]. However, most of the compounds in this series have not been examined in detail.…”

Cyclopentenyl Cytosine Induces Senescence in Breast Cancer Cells through the Nucleolar Stress Response and Activation of p53

“…Some anticancer agents induce a rapid, non-telomere-dependent form of senescence, often termed premature senescence, in cancer cells at concentrations that do not cause acute cell death in vitro or in vivo (Hornsby, 2007). These agents include phosphoinositide-3 kinase inhibitors (Collado et al, 2000), retinoic acid (Roninson and Dokmanovic, 2003), microtubule-stabilizing agents (Arthur et al, 2007), Sirt1 (Ota et al, 2006), and DNA topoisomerase inhibitors (Michishita et al, 1998), doxorubicin (Vigneron et al, 2005) and cisplatin (Varna et al, 2009). Induction of SA-␤-gal staining after chemotherapy has been observed in cells obtained from patients with breast cancer (te Poele et al, 2002), and senescence-like growth arrest has been proposed as a determinant of in vivo tumor response to both selective chemotherapeutic agents and ionizing radiation (Kahlem et al, 2004).…”