The prognosis for patients with metastasized prostate cancer is still poor, despite conventional aggressive therapeutic modalities. Several in vitro studies together with animal models and epidemiological studies have indicated that phytochemicals can be antitumorigenic and may be protective against human cancers. However, the potential antitumor effects of genistein isoflavone, a widely studied nutrient phytochemical, have been equivocal. In this study, we investigated the effects of genistein-selenium (Gn-Se) combination on chemosensitivity and matrix metalloproteinase-2 (MMP-2) expression levels in PC3 (hormone-independent) and LNCaP (hormone-dependent) prostate cancer cells. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium staining and ATP bioassay showed that genistein, selenium, and Gn-Se combination significantly inhibited growth of LNCaP and PC3 cells in a dose- and time-dependent manner, independent of hormonal status, and with no significant differences in chemosensitivity between LNCaP and PC3. Gn-Se combination induced significantly the greatest growth inhibition in both cell lines. Growth inhibition was through apoptosis induction. The treatment-induced apoptotic cascades are caspase-dependent, with evidence of an alternative non-caspase pathway(s). Treatment also induced a dose- and time-dependent decrease in MMP-2 expression levels in PC3 and LNCaP with no significant differences between the two cells. Gn-Se combination induced the greatest depression in MMP-2. Overall, none of the treatment modalities had any significant inhibitory effect in normal prostate epithelial cells. The data obtained from the present study indicate that Gn-Se combination may have chemopreventive value and/or may be adjuvant to standard therapy for prostate tumors independent of hormonal status. MMP-2 expression in cancer cells has been associated with active invasion and metastasis.

We investigated the expression of matrix metalloproteinase (MMP)-2 in human LNCaP and PC3 prostate cancer cell lines in response to genistein exposure. Initially we studied the phytosensitivity of the cells to genistein using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay to determine percentage cell viability/inhibition and the terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick end-labeling apoptosis assay to assess the type of cell death. The results revealed that genistein inhibited growth and proliferation in both PC3 (hormone-dependent) and LNCaP (hormone-independent) prostate cancer cell lines, that there was no significant difference in sensitivity to genistein between PC3 and LNCaP cells, and that the effect of genistein on the cells was dose- and time-dependent. The results also revealed that inhibition of cell growth in both PC3 and LNCaP cells was predominantly due to apoptotic cell death. These results were consistent with data in previous studies. This was followed by determination of the MMP-2 profile in response to genistein treatment. The results indicated a significant dose- and time-dependent inhibition of MMP-2 expression levels in both cells, with a highly significant negative correlation between MMP-2 levels and concentration of genistein. This is of phytotherapeutic significance in view of the pivotal role of MMP-2 expression in the pathogenesis of prostate cancer. Increasing expression of MMPs has been identified in many human cancers, including prostate cancer. Our findings indicate that genistein could be a potent therapeutic inhibitor of MMP-2 in line with current concepts of targeted treatment.

BackgroundCancer is one of the devastating neovascular diseases that incapacitate so many people the world over. Recent reports from the National Cancer Institute indicate some significant gain therapy and cancer management as seen in the increase in the 5-year survival rate over the past two decades. Although near-perfect cure rate have been reported in the early-stage disease, these data reveal high recurrence rate and serious side effects including second malignancies and fatalities. Most of the currently used anticancer agents are only effective against proliferating cancer cells. Thus attention has been focused on potential anti-cancer agents capable of killing cancer cells independent of the cell cycle state, to ensure effective elimination of most cancer cells. The objective of this study was to test the chemosensitivity and potential mechanism of action of a novel cancer drug, CytoregR, in a panel of human cancer cells.Methodsthe study was performed using a series of bioassays including Trypan blue exclusion, MTS Growth inhibition, LDH-cytotoxicity, TUNEL-Terminal DNA fragmentation Apoptosis Assay, and the Caspase protease CPP32 activity assays.ResultsCytoregR induced significant dose- and time-dependent inhibition of growth in all the cells; with significant differences in chemosensitivity (P < 0.05) between the target cells becoming more apparent at 48 hr exposure. CytoregR showed no significant effect on normal cells relative to the tumor cells. Growth inhibition in all the cells was due to induction of apoptosis at lower concentrations of cytoregR (> 1:300). CytoregR-induced caspase protease-3 (CPP32) activation significantly and positively correlated with apoptosis induction and growth inhibition; thus implicating CPP32 as the principal death pathway in cytoregR-induced apoptosis.ConclusionCytoregR exerted a dose-and time-dependent growth inhibitory effect in all the target cells through induction of apoptosis via the CPP32 death pathway, independent of hormonal sensitivity of the cells. The present data indicate that not only could CPP32 provide a potential target for regulation of cytoregR-induced apoptosis but also that cytoregR could play a significant role in chemotherapeutic regimen in many human malignant tumors.

Abstract:Background: Prostate cancer is the most common form of non-dermatologic cancer and the second leading cause of cancer deaths in the United States. Survival rate for the advanced disease still remains low, so current research is aimed at alternative or adjuvant treatments that will target components of the signal pathways in the progression of carcinogenesis with little or no cytotoxicity. In this study we investigated the effect of genistein on expression levels of genes involved in the immune response pathways. The mechanism of genistein-induced cell death was also investigated. The chemosensitivity of the LNCaP prostate cancer cells to genistein was investigated using ATP and MTS assays, and a caspase binding assay was used to determine apoptosis induction. Several molecular targets/genes were determined using cDNA microarray and RT-PCR analysis. Results:The overall data revealed that genistein induces cell death in a time-and dose-dependent manner, and regulates expression levels of several genes involved in carcinogenesis and immunity including MHC genes that are involved in immune recognition of cells and the DefB1 and the HLA membrane receptor genes involved in immunogenicity. Conclusion:The results of the study indicate that genistein inhibits carcinogenesis of LNCaP prostate cancer growth via regulation of the identified specific targets/pathways in immunogenicity/immune response. The results thus provide significant insight into the roles that genistein could play in immune response to prostate cancer proliferation and potential role in immunotherapy and/or adjuvant therapeutic regimen.

Background: In spite the heavy investments in therapeutic research breast cancer still impacts the lives of women globally. The projected incidence of new cases of in situ breast cancer in the USA for 2011 is 57,650, with estimated 39,520 deaths. The phytoestrogen, genistein and the synthetic compound, Cytoreg® have been shown to inhibit growth and proliferation in many cancer cell lines. Purpose of the Study: In this study, we investigated the therapeutic efficacy of Cytoreg®-genistein combination on growth inhibition in the MCF-7 human breast cancer cells. Method: MCF-7 cells were treated with genistein and Cytoreg® single and combination treatments for 24-48hrs; and post treatment chemosensitivity assessed, using: Trypan Blue exclusion and MTT assays for cell viability, Ethidium bromide/Acridine orange to assess apoptosis induction, and FAM Poly-Caspase binding assay for mechanism of action. Results: The overall data indicated dose- and time-dependent cell death in the MCF-cells and apoptosis as the major means of treatment-induced growth inhibition with all the treatment regimens. Conclusion: Comparatively, the genistein-Cytoreg® combination treatment was significantly more efficacious in growth inhibition in the MCF cells than either genistein or Cytoreg® alone. Genistein seems to act additively with Cytoreg® in combination treatment-induced apoptosis in MCF-7 cells. The normal human breast epithelial cells were not significantly inhibited by either single or the combination treatments.Key words: Cytoreg®, Genistein, Combination treatment, MCF- cancer cells, apoptosis