Targeting Bcl-2 Protein to Enhance Chemosensitivity of Hormone Refractory Prostate Cancer Cell Line, DU-145 by a Synergistic Combination of Docetaxel and Gossypol

WOS: 000296212300016Objective: Docetaxel has become the standard of care for hormone-refractory prostate cancer (HRPC), however drug resistance and toxicity are still challenging in daily cancer practice. The anti-apoptotic pathway centered around the Bcl-2 protein might be one of the responsible pathways. Adding a second drug to docetaxel treatment is one of the most common approaches to solve this problem. Gossypol was reported to have potent anticancer activities in prostate cancer. In this study, we searched for the possible synergistic cytotoxic/apoptotic effects of this combination treatment in hormone- and drug resistant prostate cancer cell line, DU-145 via inhibition of Bcl-2 protein. Material and Methods: XTT cell viability assay was used to assess cytotoxicity of the drugs alone and in combination. For verifying apoptosis, Cell Death Detection Elisa Plus Kit and Caspase-Glo 3/7 assay were used. Western Blot analysis for Bcl-2 protein was carried out. Results: A novel drug combination of docetaxel and gossypol resulted in a significant synergistic cytotoxic activity and apoptosis as compared to any single agent alone, in a dose- and time dependent manner, and also significantly reduced Bcl-2 protein levels in DU-145, in doses that can be used clinically. Condusion: Adding gossypol to docetaxel as a combination treatment in HRPC patients might be a solution for taxane resistant patients. Inhibition of Bcl-2 might be one of the underlying routes of activity for this combination

Effects of Thymus serpyllum Extract on Cell Proliferation, Apoptosis and Epigenetic Events in Human Breast Cancer Cells

WOS: 000311457700015PubMed ID: 23163852Thymus (T.) serpyllum (wild thyme) is an aromatic medicinal plant due to its several biological properties, including anticancer activity. Breast cancer is one of the most common malignancies and increasing evidence supports that it is not only a genetic but also an epigenetic disease. Epigenetics investigates changes in gene expression caused by mechanisms that do not involve alterations in DNA sequence. DNA methylation and histone acetylation are the most widely studied epigenetic changes in cancer cells. This study evaluated the effects of T. serpyllum on apoptosis and epigenetic events in breast cancer cells. XTT cell viability assay was used to determine cytotoxicity. DNA fragmentation and caspase 3/7 activity assays were used in the assesment of apoptosis. DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities were evaluated by ELISA and verified by qRT-PCR. T. serpyllum extract induced significant cytotoxicity in breast cancer cells (MCF-7 and MDA-MB-231) but not in normal cells. It also induced apoptosis and inhibited the DNMT and HDAC activities in MDA-MB-231 cells. In the present study, the first preliminary data on the effects of the methanolic extract of T. serpyllum in normal and breast cancer cells were obtained and suggest that T. serpyllum may be a promising candidate in the development of novel therapeutic drugs for breast cancer treatment.Medical Oncology ClinicsThis research was done at Medical Oncology Research Laboratories, School of Medicine, Tulay Aktas Oncology Hospital, Ege University. We thank Naturin Natural Products Ltd. (Izmir, Turkey) for supplying the plant material (T. serpyllum) and also thank Ruchan Uslu, M.D., who funded this research as the chairman of Medical Oncology Clinics

Comparison of XTT and Alamar blue assays in the assessment of the viability of various human cancer cell lines by AT-101 (-/- gossypol)

WOS: 000283315700008PubMed ID: 20843265This study compared the two different commercially available in vitro viability assays: XTT and Alamar blue (AB), to detect anti-proliferative effects of AT-101, a cotton plant extract, on six different human carcinoma cell lines including: prostate (PC-3 and DU-145), breast (MCF-7 and MDA-MB-231), and ovary (OVCAR-3 and MDAH 2774) in a time- and dose-dependent manner. Cells were exposed to AT-101 in the concentration range of 2.5-40 mu M for 24, 48, and 72 h. The AB assay was slightly more sensitive than the XTT assay in the evaluation of AT-101 at 24 h, suggesting that the AB assay might be used for detecting early changes in cell viability as compared to the XTT assay. Moreover, the AB assay showed less intra-assay variability as compared to the XTT. The non-toxic, non-radioactive AB metabolism assay allows rapid assessment of large numbers of samples, with simple equipment and at reduced cost for continuous monitoring of cancer cell viability, and, thus, should be accepted as a suitable alternative viability method

Enhancing cytotoxic and apoptotic effect in OVCAR-3 and MDAH-2774 cells with all-trans retinoic acid and zoledronic acid: a paradigm of synergistic molecular targeting treatment for ovarian cancer

WOS: 000282344200001PubMed ID: 20673323Background: Ovarian cancer is the most fatal gynecologic malignancies in the world. Although, platinum based treatments are widely used, the disease becomes treatment refractory within two years, and novel treatment options should be searched. All-trans retinoic acid (ATRA) induces growth arrest, differentiation and cell death in some types of cancer cells and its combination with various anticancer agents results in enhanced cytotoxicity. Zoledronic acid is a common bisphosphonate known for its anticancer effects beyond its current use in the treatment of cancer-induced bone disease. We aimed to investigate the possible additive/synergistic effect of both agents in OVCAR-3 and MDAH-2774 ovarian cancer cell lines, since both agents show superiority to conventional cytotoxics in terms of adverse events. Methods: XTT cell proliferation assay was used for showing cytotoxicity. For verifying apoptosis, both DNA Fragmentation by ELISA assay and caspase 3/7 activity measurement were used. OligoGeArray (R) which consists of 112 apoptosis related genes was used to elucidate the genetic changes within cancer cells. To validate our oligoarray results, quantitative real-time PCR was performed on four selected genes that were maximally effected by the combination treatment: lymphotoxin beta receptor (LTBR), myeloid cell leukemia-1 (MCL-1), tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), TNFRSF1A-associated death domain protein (TRADD). Results: We demonstrated that a novel combination of ATRA and zoledronic acid is a strong inducer of apoptotic related cell death in both ovarian cancer cells. While the combination therapy significantly induced proapoptotic genes such as tumor necrosis factor receptor superfamily (TNFRSF), TRADD and caspase 4, some of the antiapoptotic genes such as members of MCL-1, LTBR, BAG3 and Bcl-2 family members were inhibited. Conclusions: These are the preliminary molecular results of a novel combination treatment of ATRA and zoledronic acid, with fewer side effects as compared to conventional cytotoxic agents. With additional experimental analysis, it may serve as a good option for the treatment of refractory and elderly ovarian cancer patients, for whom there exists very limited choice of treatment