Sesamol Induces Apoptosis by Altering Expression of Bcl-2 and Bax Proteins and Modifies Skin Tumor Development in Balb/c Mice.

BACKGROUND: Chemoprevention using natural agents has emerged as a new and promising strategy for reducing cancer burden. Sesamol, a water soluble lignin, is a potent antioxidant with potential anticancer activities. Its small size (molecular weight: 138.34g) coupled with easy permeability (log P: 1.29) results in its excessive systemic loss therefore, compromising local bioavailability. Furthermore, irritant nature of sesamol limits its application on skin per se. OBJECTIVE: Present study aims to evaluate chemopreventive efficacy of free and encapsulated (SLNs) sesamol, at gross and molecular level, in DMBA induced skin cancer animal model. METHODS: Evaluation is done in terms of tumor burden quantification, histological evaluation of skin, determination of oxidative stress, and quantification of apoptotic proteins, bcl-2 and bax, using both western blot analysis and immunofluorescence studies. RESULTS: Sesamol administration (both in free and encapsulated form) significantly decreased the tumor burden and lipid peroxidation level and increased anti-oxidant levels, thereby hampering the development and promotion of skin tumors. Further, downregulation of bcl-2 and stimulation of bax protein expression on treatment with both free and encapsulated sesamol was responsible for the induction of apoptosis in tumor cells. Encapsulating sesamol into SLNs not only reduced its irritant nature which limits its direct topical application but also improved its local targeting to skin. CONCLUSION: Both free and encapsulated sesamol demonstrated the inhibition of tumor progression by inducing skin cell apoptosis via bcl-2/bax mediated pathway.

Transfection and structural properties of phytanyl substituted gemini surfactant-based vectors for gene delivery.

In this study, the transfection ability and cytotoxicity of a series of phytanyl substituted gemini surfactants, rationally designed and synthesized in an attempt to create cationic surfactants that will improve transfection efficiencies of non-viral vectors was evaluated in OVCAR-3 cells at the charge ratios (N(+)/P(-)) of 2:1, 5:1, and 10:1. Particle sizes, zeta potentials, and small angle X-ray scattering (SAXS) profiles were also determined. For each gemini surfactant complex, the transfection efficiency and cytotoxicity are observed to go through a more or less well-evidenced maximum, occurring at different values of the charge ratio (N(+)/P(-)), depending on the surfactant structure. Considering both results of in vitro transfection efficiency and cytotoxicity, the optimal charge ratio to formulate the complexes containing phy-3-m was found to be 5:1. The particle size decreased, while zeta potential increased with increasing N(+)/P(-). Comparing particle size and zeta potential with transfection efficiency, no correlation between size/zeta potential and transfection ability was observed. Analysis of SAXS profiles indicates that the ability of phy-3-m delivery system to adopt multiple phases correlated well with their higher transfection efficiency in OVCAR-3 cells.

ParAB-mediated intermolecular association of plasmid P1 parS sites.

The P1 plasmid partition system depends on ParA-ParB proteins acting on centromere-like parS sites for a faithful plasmid segregation during the Escherichia coli cell cycle. In vivo we placed parS into host E. coli chromosome and on a Sop(+) F plasmid and found that the stability of a P1 plasmid deleted for parA-parB could be partially restored when parB was expressed in trans. In vitro, parS, conjugated to magnetic beads could capture free parS DNA fragment in presence of ParB. In vitro, ParA stimulated ParB-mediated association of intermolecular parS sites in an ATP-dependent manner. However, in the presence of ADP, ParA reduced ParB-mediated pairing to levels below that seen by ParB alone. ParB of P1 pairs the parS sites of plasmids in vivo and fragments in vitro. Our findings support a model whereby ParB complexes P1 plasmids, ParA-ATP stimulates this interaction and ParA-ADP inhibits ParB pairing activity in a parS-independent manner.

Thermodynamic investigation of the binding of dissymmetric pyrenyl-gemini surfactants to DNA.

Gemini surfactants have demonstrated significant potential for use in constructing non-viral transfection vectors for the delivery of genes into cells to induce protein expression. Previously, two asymmetric gemini surfactants containing pyrenyl groups in one of the alkyl tails of the surfactants were synthesized as fluorescence probes for use in mechanistic studies of the transfection process. Here we present the results of a thermodynamic investigation of the binding interaction(s) between the pyrenyl-modified surfactants and DNA. The thermodynamics of the interactions have been examined using isothermal titration calorimetry, light scattering, zeta potential, and circular dichroism measurements. Distinct differences are observed between the interaction of 12-s-12 vs. the pyrene modified py-s-12 surfactants with DNA; an intercalated binding is found for the py-s-12 surfactants that disrupts the typical interactions observed between DNA and gemini surfactants.

Pathophysiological conditions in cholelithiasis formation in North Indian population: spectroscopic, biophysical, and biochemical study.

Knowledge of the chemical, structural, and elemental composition of gallstones is essential for etiopathogenesis of gallstone disease. To identify the predisposing factors for gallstone formation, X-ray diffraction powder analysis, atomic absorption spectroscopy, and various biochemical estimations were carried out. In the present study, trace elemental analysis revealed calcium as the major constituent element in addition to the iron, magnesium, and zinc in the majority of the gallstones. Patients with gallstones exhibited increased serum total bilirubin and conjugated bilirubin levels and liver function parameters (serum glutamic pyruvic transaminase, serum glutamic oxaloacetic transaminase, and alkaline phosphatase). In patients with gallstones, higher concentrations of malondialdehyde, significantly higher glutathione disulfide/glutathione (GSH) ratio, reduced total GSH levels, and significantly decreased antioxidant enzymes activities (superoxide dismutase, catalase, and glutathione peroxidase) were found than in patients without gallstones. Further studies are needed to establish whether the observed differences are a cause or an effect of gallstone formation. Such studies could ultimately result in the development of new strategies for the treatment of gallstones and might provide clues for prevention of gallstones formation.

Addressing the challenge: current and future directions in ovarian cancer therapy.

Numerous ovarian gene therapy strategies are in clinical phases based on concepts of replacement/ knock out of deregulated gene, suicide gene strategies, strengthening of the immune response against a tumor, inhibition of tumor angiogenesis and growth factors. Non-viral delivery systems have potential advantages over currently widely used viral vectors and other classical vectors for delivering therapeutic gene of interest. The present review provides a comprehensive overview of potential of various delivery systems currently in use. Non-viral formulations used in ovarian gene therapy include injecting naked DNA, liposomes, polyplexes, lipopolyplexes, nanoparticles, gene gun and ultrasound/microbubble mediated gene delivery. In addition to improving vector delivery, the DNA constructs need to be optimised for both efficient and long-term transgene expression. Minicircles using minimal immunological defined gene expression (MIDGE) technology, are a promising future alternative to plasmid for use in non-viral ovarian gene therapy in terms of biosafety, improved gene transfer, potential bioavailability, minimal size and little immune reaction. The review explores the best route of administration for ovarian cancer gene therapy given its peritoneal dissemination which poses a major challenge in treating ovarian cancer patients. Enhancement of therapeutic index can be further achieved by overcoming barriers both at cellular and nuclear levels. Selective tumor targeting with minimal toxicity using folate modified, incorporating nuclear localization signal and PEGylated stealth liposome's represents a popular approach and needs to be exploited in ovarian gene therapy.

Interplay between oncoproteins and antioxidant enzymes in esophageal carcinoma treated without and with chemoradiotherapy: a prospective study.

PURPOSE: To analyze p53, bcl-2, c-myc, and cyclooxygenase-2 protein expression changes and examine their relationship with various antioxidant enzymes in esophageal carcinoma patients. METHODS AND MATERIALS: Patients in Group 1 underwent transhiatal esophagectomy and those in Group 2 were administered chemoradiotherapy followed by surgery after 4 weeks of neoadjuvant therapy. RESULTS: The relationship analysis among the various protein markers and antioxidant enzymes showed an inverse correlation between bcl-2 and superoxide dismutase/catalase in tumor tissues, irrespective of the treatment arm followed. An important positive association was observed between bcl-2 and reduced glutathione levels in the tumor tissue of patients receiving neoadjuvant therapy. Another apoptosis-modulating marker, c-myc, in the tumor tissue of Group 2 patients showed similar pattern levels (high and low) as that of superoxide dismutase/catalase. The association of cyclooxygenase-2 and p53 with various antioxidant enzymes showed a significant positive correlation between cyclooxygenase-2 expression and catalase activity and an inverse trend between p53 expression and superoxide dismutase and catalase activity in the tumor tissue of patients given neoadjuvant therapy. In addition, patients with overexpressed p53 protein levels had lower glutathione peroxidase enzyme levels and vice versa in the tumor tissue of patients who had undergone surgery as their main mode of treatment. CONCLUSION: The results of this study broaden the insight into the relationships shared among oncoproteins and the antioxidant defense system, and this could be helpful in the clinical management of esophageal carcinoma.

Effects of green tea extract on learning, memory, behavior and acetylcholinesterase activity in young and old male rats.

OBJECTIVE: To study the effects of green tea extract administration on age-related cognition in young and old male Wistar rats. METHODS: Young and old rats were orally administered 0.5% green tea extract for a period of eight weeks and were evaluated by passive avoidance, elevated maze plus paradigm and changes in acetylcholinesterase activity. RESULTS: Treatment of young and old rats with the extract resulted in no significant difference in performance on the rota rod treadmill test/righting reflex time. Green tea extract significantly improved learning and memory in older rats, with increased retention latency to enter difference in passive avoidance test. In the elevated maze test, green tea treatment resulted in significantly more number of entries in the enclosed arm by the young and old rats. Decline in acetylcholinesterase activity was observed in the cerebrum of green tea treated old rats in comparison to the green tea treated young rats. CONCLUSION: Green tea extract administration is effective in enhancing learning and memory in aged rats, and hence, may serve useful in reversing age-related deficits.

Growth characteristics and selenium status changes of yeast cells with inorganic and organic selenium supplementation: selenium, a chemopreventive agent.

We attempted to determine the level and form of selenium (Se) that yielded the maximum Se status of yeast cells, for their evaluation as a source of Se for chemopreventive action. The influence of various Se concentrations from organic (selenomethionine) and inorganic (sodium selenite) Se compounds on growth pattern and cell viability and the alterations in the antioxidant enzyme system of yeast were evaluated. A continuous decrease in cell and colony-forming units counts was observed with increasing concentrations of Se from either source. Increasing Se status of yeast cells was found with increasing concentrations of Se with both forms, with much greater uptake for organic Se at maximum Se concentrations. A continuous increase in glutathione peroxidase (GSH-Px) activity with increasing Se concentrations in both forms revealed an active Se response in terms of antioxidant activity, with a more pronounced percentage increase with selenomethionine. A highly significant increase in total glutathione was observed with selenomethionine supplementation, compared with sodium selenite. A decreasing trend in reduced glutathione was observed with increasing organic or inorganic Se concentrations. An increasing trend in glutathione-S-transferase activity was observed with increasing Se concentrations for both forms. Significantly higher values of glutathione-S-transferase were associated with the organic form at higher Se concentrations. There was normal activity of Se in mammalian cells. The results showed that an organic Se source more greatly enhances the Se status of yeast cells and hence could help in chemoprevention if consumed by the population.