ABSTRACT
Natural products represent the source or the inspiration for the majority of the active ingredients of medicines because of their structural diversity and a wide range of biological effects. Our aims in this study were (i) to synthesize enzymatically salidroside (SAL), the most effective phenylethanoid glycoside in Rhodiola species; (ii) to examine its antioxidant capacity using cell-free assays (reducing power, DPPH radicals scavenging and Fe2+ -chelating assays); (iii) to assess its DNA-protective potential on plasmid DNA (DNA topology assay) and in HepG2 cells (comet assay) damaged by Fe2+ ions and hydrogen peroxide, respectively; and (iv) to investigate the effects of SAL, cisplatin (CDDP) and combined treatments of SAL + CDDP on cell viability (MTT test), level of DNA damage (comet assay), proliferation, cell cycle (flow cytometry) and the expression of signalling molecules associated with cell growth and apoptotic pathways (Western immunoblotting). We found out that SAL manifested low antioxidant and DNA-protective capacity in all assays used. In both parental A2780 and CDDP-resistant A2780/CP human ovarian carcinoma cells, SAL itself exerted in fact no impact on the viability, while in combination with CDDP it showed antagonistic effect supporting the chemopreventive activity on the CDDP-induced cell damage. These results were confirmed by the partial reversal of the cell cycle alterations and the DNA damage level, as well as with partial restoration of cell survival/signalling pathways, when the expression of these molecules partially returned to their proper levels.
Subject(s)
Anticarcinogenic Agents/pharmacology , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Cisplatin/pharmacology , Glucosides/pharmacology , Hepatocytes/drug effects , Ovarian Neoplasms/drug therapy , Phenols/pharmacology , Antineoplastic Agents/adverse effects , Antineoplastic Agents/chemistry , Antioxidants/pharmacology , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Cisplatin/adverse effects , Cisplatin/agonists , Cisplatin/antagonists & inhibitors , Comet Assay , DNA Damage/drug effects , Drug Antagonism , Drug Synergism , Female , Hep G2 Cells , Hepatocytes/cytology , Humans , Ovarian Neoplasms/pathology , Protective Agents/pharmacology , Reproducibility of Results , Signal Transduction/drug effectsABSTRACT
Cisplatin resistance is one of the major obstacles in the treatment of ovarian cancer. In an effort to look for new possibilities of how to overcome this difficulty, we studied the mechanisms of the interactions between sulforaphane (SFN) and cisplatin (cisPt) in combined treatment of human ovarian carcinoma A2780 and SKOV3 cell lines. Synergy (A2780) and antagonism (SKOV3) found in MTT assay was confirmed by apoptosis. While SFN significantly potentiated cisPt-induced DNA damage in A2780 cells, it protected SKOV3 cells against cisPt-crosslinking. We revealed a less efficient Nrf-2 pathway inducibility by SFN in A2780 compared to SKOV3 cells, when activation of the Nrf-2 pathway incites its protectivity against cisPt. Thus, different activation of the Nrf-2 pathway may explain the dual effects of SFN.
Subject(s)
Antineoplastic Agents/pharmacology , Cisplatin/pharmacology , Drug Resistance, Neoplasm , Isothiocyanates/pharmacology , Ovarian Neoplasms/metabolism , Antineoplastic Combined Chemotherapy Protocols , Apoptosis/drug effects , Cell Line, Tumor , Comet Assay , DNA Damage/drug effects , Female , Gene Expression Regulation, Neoplastic , Humans , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Ovarian Neoplasms/drug therapy , Signal Transduction , SulfoxidesABSTRACT
Dendritic cells (DCs) and natural killer (NK) cells are central components of innate immunity for controlling tumor growth. The therapeutic effects of certain anti-myeloma drugs are partially mediated by targeting the innate immune response. In addition, novel types of natural compounds have been developed that efficiently modulate the activity of both the cellular and humoral compartments of immunity. MGN-3 is known as an activator of natural killer cells, inducer of apoptosis and cytokine production, and modulator of dendritic cell maturation and differentiation in vitro. We have performed a randomized, placebo-controlled study to examine the effects of MGN-3 on innate immune system parameters in 48 multiple myeloma patients. We performed immunophenotypic analysis of peripheral blood samples, determined NK cell activity, and assessed the cytokine profiles of plasma before and during 3 months of treatment. The results demonstrate a clear increase in NK activity in MGN-3-treated patients compared to the placebo group, an increased level of myeloid DCs in peripheral blood, and augmented concentrations of T helper cell type 1-related cytokines. The present study suggests that MGN-3 may represent an immunologically relevant product for activating innate immunity in multiple myeloma patients and warrants further testing to demonstrate clinical efficacy.
Subject(s)
Dendritic Cells/immunology , Immunity, Innate/drug effects , Killer Cells, Natural/immunology , Multiple Myeloma/immunology , Xylans/pharmacology , Aged , Aged, 80 and over , Cytokines/metabolism , Dendritic Cells/drug effects , Female , Humans , Killer Cells, Natural/drug effects , Male , Middle Aged , Multiple Myeloma/drug therapy , Oryza/chemistryABSTRACT
BACKGROUND: Multidrug resistance (MDR) modulator PSC 833 has been shown to modulate multidrug resistance in Pg-p-positive human ovarian carcinoma cells A2780/ADR. Co-treatment of A2780/ADR cells with paclitaxel (PTX) and PSC 833 resulted in the restoration of PTX-sensitivity comparable to that in parental A2780 cells. RESULTS: The flow cytometry experiments presented here showed PTX-(A2780) and PTX plus PSC 833 (A2780/ADR)-induced cell accumulation in the G2/M-phase of the cell cycle with concomitant appearance of apoptotic cells with sub-G0 (hypodiploid) DNA content. Furthermore, these events were accompanied by the appearance of poly(ADP-ribose) polymerase (PARP) cleavage, up-regulation of Bax, p53 and p21WAF1/CIP1 proteins and internucleosomal DNA fragmentation. Interestingly, we did not detect any significant alterations in Bcl-xL, CD95/Fas and Fas-L protein levels. CONCLUSION: These results demonstrate the PSC 833 reduced the Pg-p-mediated multidrug resistance in human ovarian carcinoma cells to PTX-induced apoptosis in vitro.
