Inhibition of ornithine decarboxylase alters the roscovitine-induced mitochondrial-mediated apoptosis in MCF-7 breast cancer cells

Abstract

Abstract. Polyamines (PAs) are small aliphatic amines that play a major role in multicellular functions. The PA levels are controlled by ornithine decarboxylase (ODC), the rate limiting enzyme of PA biosynthesis. α-difluoromethylornithine (DFMO) is the ODC inhibitor, which has been shown to act as an antiproliferative agent in human cancer cells by irreversibly inhibiting ODC, which is overexpressed in breast cancer cells. Roscovitine (ROSC; CYC202), a selective cyclin-dependent kinase inhibitor, induces cell cycle arrest and concomitantly apoptosis in tumor cells. In this study, we aimed to investigate the possible role of PAs in ROSC-induced apoptosis in estrogen-dependent MCF-7 breast cancer cells. Cell viability was assessed following the exposure of MCF-7 cells to DFMO and/or ROSC by MTT cell viability assay. To evaluate the druginduced apoptotic events, DNA fragmentation by Cell Death ELISA assay and 4,6-diamidino-2-phenylindole staining, were utilized. The disruption of mitochondrial membrane potential, caspase-9 and PARP cleavage was also determined in order to investigate the role of mitochondrial-mediated apoptosis. The modulation of Bcl-2 family members was also evaluated using the immunoblotting technique. Drug-induced reactive oxygen species was determined by a fluorometer following 2' ,7'-dichlorofluorescein diacetate staining. We found that ROSC induced apoptosis in a dose-and caspase-dependent manner. The ODC specific inhibitor, DFMO, altered the apoptotic effects of ROSC by increasing the generation of reactive oxygen species, decreasing the PA intracellular pool and modulating pro-apoptotic and anti-apoptotic Bcl-2 family members. All these findings suggest that ODC may be a critical target for evaluating the PA metabolic pathway as a therapeutic target in ROSC-induced mitochondrial-mediated apoptotis in estrogendependent MCF-7 breast cancer cells.

Cyclin-dependent kinase inhibitor dinaciclib potently synergizes with cisplatin in preclinical models of ovarian cancer

“…In addition, several anti-oxidant agents including vitamin E are able to induce apoptosis in cancer cells [ 37 ]. Similar to other CDK inhibitors flavopiridol and roscovitine [ 38 , 39 ], dinaciclib also can enhance the intracellular ROS levels, and NAC pretreatment dramatically blocks ROS generation but partially rescues dinaciclib-induced apoptosis in the current study. Our results suggest that dinaciclib is able to prompt both ROS dependent and independent apoptosis in ovarian cancer cells.…”

Targeting ornithine decarboxylase (ODC) inhibits esophageal squamous cell carcinoma progression

“…Conversely, suppression of ODC expression is associated with decreased cell proliferation, increased apoptosis and decreased expression of genes affecting tumor invasion and metastasis. 27 , 28 Our data showed that when ODC expression in ESCC cells was knocked down, both proliferation and anchorage-independent growth of ESCC cells were significantly suppressed (Fig. 2c, d ).…”

Alpha-Difluoromethylornithine, an Irreversible Inhibitor of Polyamine Biosynthesis, as a Therapeutic Strategy against Hyperproliferative and Infectious Diseases

“…Studies showed that DFMO is effective in preventing pancreatic cancer in genetically engineered KRAS mice [ 110 ] and furthermore that the combination therapy of ODC and polyamine transport inhibition in pancreatic cancer cell lines and pancreatic cancer mouse models inhibited cancer cell survival and prolonged the survival of tumor bearing mice [ 106 , 108 ]. Other areas of prolific research include but are not limited to skin, endometrial, and breast cancer [ 111 , 112 , 113 , 114 , 115 , 116 ]. Clinical trials with DFMO are ongoing for prostate cancer, skin cancer and precancerous conditions, gastric cancer, bladder cancer, the rare brain cancer anaplastic astrocytoma, cervical cancer, and esophageal cancer ( ).…”