Anil K. Balapure

Pharmacological inhibition of gut-derived serotonin synthesis is a potential bone anabolic treatment for osteoporosis

Osteoporosis is a disease of low bone mass most often caused by an increase in bone resorption that is not sufficiently compensated for by a corresponding increase in bone formation. As gut-derived serotonin (GDS) inhibits bone formation, we asked whether hampering its biosynthesis could treat osteoporosis through an anabolic mechanism (that is, by increasing bone formation). We synthesized and used LP533401, a small molecule inhibitor of tryptophan hydroxylase-1 (Tph-1), the initial enzyme in GDS biosynthesis. Oral administration of this small molecule once daily for up to six weeks acts prophylactically or therapeutically, in a dose-dependent manner, to treat osteoporosis in ovariectomized rodents because of an isolated increase in bone formation. These results provide a proof of principle that inhibiting GDS biosynthesis could become a new anabolic treatment for osteoporosis.Osteoporosis is a disease of low bone mass most often caused by an increase in bone resorption that is not sufficiently compensated for by a corresponding increase in bone formation. As gut-derived serotonin (GDS) inhibits bone formation, we asked whether hampering its biosynthesis could treat osteoporosis through an anabolic mechanism (that is, by increasing bone formation). We synthesized and used LP533401, a small molecule inhibitor of tryptophan hydroxylase-1 (Tph-1), the initial enzyme in GDS biosynthesis. Oral administration of this small molecule once daily for up to six weeks acts prophylactically or therapeutically, in a dose–dependent manner, to treat osteoporosis in ovariectomized rodents because of an isolated increase in bone formation. These results provide a proof of principle that inhibiting GDS biosynthesis could become a new anabolic treatment for osteoporosis.

Molecular iodine induces caspase-independent apoptosis in human breast carcinoma cells involving the mitochondria-mediated pathway.

Molecular iodine (I2) is known to inhibit the induction and promotion of N-methyl-n-nitrosourea-induced mammary carcinogenesis, to regress 7,12-dimethylbenz(a)anthracene-induced breast tumors in rat, and has also been shown to have beneficial effects in fibrocystic human breast disease. Cytotoxicity of iodine on cultured human breast cancer cell lines, namely MCF-7, MDA-MB-231, MDA-MB-453, ZR-75-1, and T-47D, is reported in this communication. Iodine induced apoptosis in all of the cell lines tested, except MDA-MB-231, shown by sub-G1 peak analysis using flow cytometry. Iodine inhibited proliferation of normal human peripheral blood mononuclear cells; however, it did not induce apoptosis in these cells. The iodine-induced apoptotic mechanism was studied in MCF-7 cells. DNA fragmentation analysis confirmed internucleosomal DNA degradation. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling established that iodine induced apoptosis in a time- and dose-dependent manner in MCF-7 cells. Iodine-induced apoptosis was independent of caspases. Iodine dissipated mitochondrial membrane potential, exhibited antioxidant activity, and caused depletion in total cellular thiol content. Western blot results showed a decrease in Bcl-2 and up-regulation of Bax. Immunofluorescence studies confirmed the activation and mitochondrial membrane localization of Bax. Ectopic Bcl-2 overexpression did not rescue iodine-induced cell death. Iodine treatment induces the translocation of apoptosis-inducing factor from mitochondria to the nucleus, and treatment of N-acetyl-l-cysteine prior to iodine exposure restored basal thiol content, ROS levels, and completely inhibited nuclear translocation of apoptosis-inducing factor and subsequently cell death, indicating that thiol depletion may play an important role in iodine-induced cell death. These results demonstrate that iodine treatment activates a caspase-independent and mitochondria-mediated apoptotic pathway.

Centchroman induces G0/G1 arrest and caspase-dependent apoptosis involving mitochondrial membrane depolarization in MCF-7 and MDA MB-231 human breast cancer cells.

Studies with Centchroman (CC) as a candidate anti-breast cancer agent are into phase III multicentric clinical trial in stage III/IV breast cancer. We have previously demonstrated its anti-neoplastic activity in Estrogen Receptor positive (ER+ve) MCF-7 Human Breast Cancer Cells (HBCCs). We now present the basis for anti-neoplastic activity of CC, mediated through apoptosis in both ER+ve/-ve MCF-7 and MDA MB-231 HBCCs respectively, compared to Tamoxifen (TAM) as a positive control. All the experiments were performed with 48 h estrogen-deprived cells exposed to CC/TAM for the subsequent 48 h. Cytotoxic potential of CC was assessed through SRB assay. Cell-cycle analysis, Time-dependent cytotoxicity, Reactive Oxygen Species (ROS) and Mitochondrial Membrane Permeability were investigated by Flow Cytometry. Early-stage apoptosis was detected by Annexin-PI staining. Caspases were assayed colorimetrically whereas nuclear derangements were assessed morphologically through PI staining and finally by DNA fragmentation analysis. Cell viability studies confirmed the IC50 of CC in MCF-7 and MDA MB-231 cells to be 10 and 20 microM (P < 0.001) respectively, suggesting enhanced susceptibility of the former cell type to CC. FACS data reveals CC mediated G0/G1 arrest (P < 0.01) along with the presence of prominent sub-G0/G1 peak (P < 0.001) in both the cell types suggesting ongoing apoptosis. Phosphatidylserine externalization, mitochondrial events, caspase evaluation and nuclear morphology changes reveal initiation/progression of caspase-dependent apoptosis even at a dose of 1 microM which eventually leads to DNA fragmentation in both the cell types. Results demonstrate that CC induces caspase-dependent apoptosis in MCF-7 and MDA MB-231 cells irrespective of ER status similar to TAM in terms of anti-neoplastic activity.

Resveratrol as an adjunct therapy in cyclophosphamide-treated MCF-7 cells and breast tumor explants

Cyclophosphamide (CPA) has efficacy as a breast cancer therapy. However, toxicity to CPA limits its clinical applications. Hence there is a need to develop compounds that may be combined with it to improve the efficacy and overcome toxicity. We showed previously that Resveratrol (RES), a chemopreventive agent, increased the growth inhibitory effect of CPA‐treated MCF‐7 cells. Here we have explored the molecular basis of 5 mM CPA and 50 μM RES as a combination on cell‐cycle progression, apoptosis and oxidative stress in MCF‐7 breast cancer cells. Efficacy of the combination was also evaluated in a serum‐free tumor explant culture model. The combination elicited enhanced anti‐proliferative action coupled with differential expression of cell‐cycle, apoptosis and stress factors. Furthermore, co‐treatment superiority in histologically validated ER positive breast cancer explants suggests that this combination may be a worthy future clinical anti‐neoplastic regimen. (Cancer Sci 2011; 102: 1059–1067)

Differential action of iodine on mitochondria from human tumoral- and extra-tumoral tissue in inducing the release of apoptogenic proteins

Iodide is actively concentrated in the thyroid gland for thyroid hormone biosynthesis. Excess iodine has been observed to induce apoptosis in thyrocytes and mammary cells. The mechanism of iodine induced apoptosis is poorly understood. Among various cell organelles, mitochondria is known to provide conducive environment for the organification of iodine, i.e. iodination of different proteins. Mitochondria also play a central role in execution of apoptosis. To study the role of mitochondria in iodine induced apoptosis, we investigated the direct interaction of iodine and human breast mitochondria vis-a-vis its role in the initiation of apoptosis in vitro. We observed that mitochondria isolated from the tumor (TT) and extra-tumoral tissue (ET) of human breast display significant uptake of iodine. Mitochondrial proteins were observed to be predominantly iodinated in ET but not in TT mitochondria. Treatment with iodine showed an increase in mitochondrial permeability transition of TT and decrease in ET. Iodine induced released factor(s) other than cytochrome c from tumor mitochondria initiate(s) apoptosis in vitro, while those from ET mitochondria were non-apoptogenic in nature. To our knowledge, this is first report demonstrating that iodine acts differentially on mitochondria of tumor and extratumoral origin to release apoptogenic proteins from TT and has a protective effect on ET.

Stimulatory effect of Ceriops tagal on hexose uptake in L6 muscle cells in culture

The ethanolic extracts of a mangrove plant Ceriops tagal (Family Rhizophoraceae) and its sequential fractions thereof were studied for their effect on 3H-2-deoxyglucose uptake by L6 rat muscle cells cultured to the myotube stage. Among these, the n-hexane soluble fraction of ethanolic extract of the leaves of C. tagal enhanced 3H-2-deoxyglucose uptake even at 2 µg mL−1 concentration with half maximum activity at 10 µg mL−1, comparable with insulin (1 µM) and metformin (400 µM). This enhancement in glucose uptake was found to be insulin independent and in contrast to insulin, its effect was also prevalent in undifferentiated myoblasts. It may be concluded from the results that n-hexane soluble fraction of ethanolic extract of C. tagal have the property to stimulate the glucose uptake, which might be a useful source for the isolation of new antihyperglycemic compounds.

Histological and ultrastructural regulation in rabbit endometrial explants by estrogen in serum-free culture

SummaryA repertoire of hormonal signals including estrogen regulate the growth, differentiation, and functioning of diverse target tissues, including the ovary, the mammary gland, and skeletal tissue. A serum-free culture system derived from rabbit endometrium explants has been devised and is reported here to explore estrogen action in vitro. The system involves aseptically harvesting the uterus from a virgin rabbit, dissecting the endometrium, explanting it into 1- to 2-mm3 pieces weighing approximately 1–2 mg each, and incubating these pieces in serum-free Medium-199. The culture is carried out for a period of 4 d in a humidified CO2 incubator at 37°C with 5% CO2. The effect of extraneously added estrogen (1 μg/ml) was investigated by histological and ultrastructural procedures. It was observed that estrogen could induce specific changes, such as abundant mitochondria, rough endoplasmic reticulum, golgi complex, and intracellular collagen deposition, in both the epithelial and the fibroblast cell components of the explanted tissue. The study, therefore, indicates that the proposed system is an ideal tool for exploring and demonstrating estrogen responsiveness under in vitro conditions.

Centchroman regulates breast cancer angiogenesis via inhibition of HIF-1α/VEGFR2 signalling axis

Aims: Angiogenesis is a recognized hallmark of cancer which promotes cancer cell progression and metastasis. Inhibition of angiogenesis to attenuate cancer growth is becoming desirable strategy for breast cancer management. The present study is aimed to investigate the antiangiogenic efficacy of a novel selective estrogen receptor modulator Centchroman (CC) on human breast cancer cells. Main methods: Effect of CC on cell viability was evaluated using Sulforhodamine B assay. Endothelial cell proliferation, wound healing, Boyden chamber cell invasion, tube formation and chorioallantoic membrane (CAM) assays were performed to assess the effect of CC on migration, invasion and angiogenesis. Apoptosis, reactive oxygen species generation, caspase‐3/7 and intracellular calcium ion level were measured through flow cytometry. Expression levels of HIF‐1&agr;, VEGF, VEGFR2, AKT and ERK were assessed by western blot analysis. Key findings: CC selectively induces apoptosis in human breast cancer cells without affecting non‐tumorigenic breast epithelial cells MCF‐10A. Moreover, it inhibits migratory, invasive and mammosphere forming potential of breast cancer. Furthermore, CC also inhibited VEGF‐induced migration, invasion and tube formation of HUVECs in vitro. CC effectively inhibited neovasculature formation in chicken CAM. Western blot analysis demonstrated that CC inhibited expression of HIF‐1&agr; and its downstream target VEGF. Interestingly, CC also suppressed VEGFR2 phosphorylation and consequently attenuated AKT and ERK phosphorylation. Significance: Our findings suggest that CC downregulates VEGF‐induced angiogenesis by modulating HIF‐1&agr;/VEGFR2 pathway and recommend it (CC) as a potential therapeutic drug for breast cancer treatment. Graphical abstract: Figure. No Caption available. Highlights:Centchroman (CC) exerts antiangiogenic response in human breast cancer.CC prevents neovasculature formation in chicken CAM.CC stops invasion and migration in HUVEC and breast cancer cells.CC supresses hypoxia induced HIF‐1&agr; and VEGF signalling pathways in endothelial and breast cancer cells.

Insulin catalyzes the curcumin-induced wound healing: An in vitro model for gingival repair

Objectives: Human gingival fibroblasts (hGFs) play a major role in the maintenance and repair of gingival connective tissue. The mitogen insulin with IGFs etc. synergizes in facilitating wound repair. Although curcumin (CUR) and insulin regulate apoptosis, their impact as a combination on hGF in wound repair remains unknown. Our study consists of: 1) analysis of insulin-mediated mitogenesis on CUR-treated hGF cells, and 2) development of an in vitro model of wound healing. Materials and Methods: Apoptotic rate in CUR-treated hGF cells with and without insulin was observed by AnnexinV/PI staining, nuclear morphological analysis, FACS and DNA fragmentation studies. Using hGF confluent cultures, wounds were mechanically created in vitro and incubated with the ligands for 48 h in 0.2% fetal bovine serum DMEM. Results: CUR alone showed dose-dependent (1–50 μM) effects on hGF. Insulin (1 μg/ml) supplementation substantially enhanced cell survival through up-regulation of mitogenesis/anti-apoptotic elements. Conclusions: The in vitro model for gingival wound healing establishes that insulin significantly enhanced wound filling faster than CUR-treated hGF cells over 48 h. This reinforces the pivotal role of insulin in supporting CUR-mediated wound repair. The findings have significant bearing in metabolic dysfunctions, e.g. diabetes, atherosclerosis, etc., especially under Indian situations.

In vitro Maintenance of Olfactory Mucosa with Enriched Olfactory Ensheathing Cells

Human Olfactory Mucosa (OM) regulates olfaction through axonal regeneration and myelination mediated by stem cells and Olfactory Ensheathing Cells (OECs) resident in the niche. Purified OECs/olfactory biopsies have been utilized for functional recovery in different Spinal Cord Injury (SCI) models. However, recent reports find this debatable where we propose primary culture of OM, basal cells of olfactory epithelium and olfactory ecto-mesenchymal stem cells. Our defined culture conditions improve the life span of OM with enrichment of OECs providing a strategy for employment for SCI/cochlear damage repair. Briefly, OM post-collection, was non-enzymatically sliced, cultured for 6 weeks and cells characterized morphologically, immuno-cytochemically and western blotting. By day 21, ~70% GFAP and p75NTR stained, spindle shaped astrocyte-like and flattened sheet-like OECs displayed axonal remyelination. By day 30, caspase 3, 8, 9 (gene-product and activity), phospho-p53 negative; GFAP and p75NTR positive dense, overlapping mass of cells was found. This was accompanied with degenerative changes by 6 weeks through GFAP staining. Conversely, trypsination on day 21 resulted in >95% OECs with flattened morphology, GFAP and p75NTR positivity. The human derived OECs were compared with the 2-day SD rat Olfactory Bulb Cells cultured for 2 weeks in F12 media (GFAP and p75NTR positive). Hence, cultured olfactory mucosa displaying axonal regeneration with OECs in culture provides a vehicle for SCI/cochlear damage repair studies.