CXCR4 is a novel target of cancer chemopreventative isothiocyanates in prostate cancer cells

Isothiocyanates (ITCs) derived from cruciferous vegetables, including phenethyl isothiocyanate (PEITC) and sulforaphane (SFN), exhibit in vivo activity against prostate cancer in a xenograft and transgenic mouse model, and thus are appealing for chemoprevention of this disease. Watercress constituent PEITC and SFN-rich broccoli sprout extract are under clinical investigations but the molecular mechanisms underlying their cancer chemopreventive effects are not fully understood. The present study demonstrates that chemokine receptor CXCR4 is a novel target of ITCs in prostate cancer cells. Exposure of prostate cancer cells (LNCaP, 22Rv1, C4-2, and PC-3) to pharmacologically applicable concentrations of PEITC, benzyl isothiocyanate (BITC), and SFN (2.5 and 5 μmol/L) resulted in downregulation of CXCR4 expression. None of the ITCs affected secretion of CXCR4 ligand (stromal-derived factor-1). In vivo inhibition of PC-3 xenograft growth upon PEITC treatment was associated with a significant decrease in CXCR4 protein level. A similar trend was discernible in the tumors from SFN-treated TRAMP mice compared with those of control mice, but the difference was not significant. Stable overexpression of CXCR4 in PC-3 cells conferred significant protection against wound healing, cell migration, and cell viability inhibition by ITCs. Inhibition of cell migration resulting from PEITC and BITC exposure was significantly augmented by RNAi of CXCR4. This study demonstrates, for the first time, that cancer chemopreventive ITCs suppress CXCR4 expression in prostate cancer cells in vitro as well as in vivo. These results suggest that CXCR4 downregulation may be an important pharmacodynamic biomarker of cancer chemopreventative ITCs in prostate adenocarcinoma.

The role of polycomb group protein Bmi-1 and Notch4 in breast cancer stem cell inhibition by benzyl isothiocyanate

We showed previously that garden cress constituent benzyl isothiocyanate (BITC) inhibits self-renewal of breast cancer stem cells (bCSC) in vitro and in vivo. The present study offers novel insights into the mechanism by which BITC inhibits bCSC. Flow cytometry and mammosphere assay were performed to quantify bCSC fraction. Protein expression was determined by western blotting. Apoptosis was assessed by flow cytometry using Annexin V-propidium iodide method. Cell migration was determined by Boyden chamber assay. BITC treatment resulted in a marked decrease in protein level of polycomb group protein B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) in cultured human breast cancer cells (MCF-7, SUM159, MDA-MB-231, and MDA-MB-361) and MDA-MB-231 xenografts in vivo. Overexpression (MCF-7) or knockdown (SUM159, and MDA-MB-231) of Bmi-1 protein had no meaningful impact on the BITC's ability to inhibit cell viability and cell migration and/or induce apoptosis. On the other hand, inhibition of bCSC markers (aldehyde dehydrogenase 1 activity and mammosphere frequency) resulting from BITC exposure was significantly altered by Bmi-1 overexpression and knockdown. BITC was previously shown to cause activation of Notch1, Notch2, and Notch4 in association with induction of γ-secretase complex component Nicastrin, which are also implicated in maintenance of cancer stemness. BITC-mediated inhibition of bCSC was augmented by knockdown of Notch4 and Nicastrin, but not by RNA interference of Notch1 or Notch2. The present study highlights important roles for Bmi-1 and Notch4 in BITC-mediated suppression of bCSC.

'Bio-load' and bio-type profiles of Mycobacterium avium subspecies paratuberculosis infection in the domestic livestock population endemic for Johne's disease: a survey of 28 years (1985-2013) in India

Bio-load and bio-profile of Mycobacterium avium subspecies paratuberculosis was studied in the domestic livestock population of the country. Of the 23,429 farm and farmer's animals screened, average bio-load was 23.3% (Period of study; 28 years for goats; 13 years for sheep, cattle and buffaloes). Species-wise, bio-load was 20.1, 32.7, 39.3 and 28.3% in goats, sheep, cattle and buffaloes, respectively. Bio-load was significantly lower in time period A (P < 0.001) and B (P < 0.03), compared with period C. Geographical zone-wise, bio-load of MAP was significantly higher (P < 0.05) in Central zone compared with South, West, East and North zones. Bio-load in 11 states ranged from 16.2 to 87.8%. Of 8450, 5643, 8185 and 1151 samples screened by microscopy, culture, indigenous ELISA and IS900 blood PCR, 20.0, 10.6, 35.1 and 26.6% samples were positive, respectively. Bio-load was 32.8 and 31.6% in farm and farmer's goats and sheep, respectively, and 62.1% in farmer's cattle. MAP bio-load was also monitored in four farm units (three goats and one sheep) for breed improvement and three farm goats units for experimental purposes at Central Institute for Research on Goats in Mathura district. Of the 8025 goats and 1525 sheep that died from 1988 to 2013, 10.9 and 3.0% deaths were due to JD, respectively. On the basis of JD and suspected JD, 10.0 and 28.4% goats and 2.2 and 40.9% sheep, respectively were culled from the farm units in 25 years. Microscopic examination of 214 tissues (mesenteric lymph nodes and intestines) of 107 animals, it was observed that bio-load of MAP was high (25.0-60.0%) in farm animals. 'Indian Bison Type' was the dominant biotype, irrespective of domestic livestock species and the geographical zone.

Abstract 228: Withaferin A downregulates tubulins and covalently binds β-tubulin at cysteine-303 in human breast cancer cells

We have shown previously that withaferin A (WA), a C5,C6-epoxy steroidal lactone derived from an Ayurvedic medicine plant (Withania somnifera), not only inhibits growth of human breast cancer cells in vitro and in vivo but also prevents mammary cancer development in a transgenic mouse model without any toxicity. However, the mechanisms underlying cancer preventive effect of WA are not fully understood. Herein, we report that tubulin is a novel target of WA in human breast cancer cells. WA treatment resulted in G2 and mitotic arrest in MCF-7 (estrogen-receptor positive), SK-BR-3 (estrogen-receptor negative), and SUM159 (triple-negative) cells in association with a marked decrease in protein level of β-tubulin. These effects were not observed with the naturally-occurring C6,C7-epoxy analogs of WA (withanone and withanolide A). In addition, a non-tumorigenic normal human mammary epithelial cell line (MCF-10A) was markedly more resistant to mitotic arrest and tubulin downregulation by WA treatment compared with breast cancer cells. Downregulation of tubulin protein in WA-treated cells was due to transcriptional repression as well as proteasomal degradation. Vehicle-treated control breast cancer cells exhibited a normal bi-polar spindle with chromosomes aligned along the metaphase plate. In contrast, WA treatment led to a severe disruption of the normal spindle morphology in breast cancer cells. Unlike breast cancer cells, WA-treated MCF-10A cells exhibited aggregation of tubulin around nucleus. NMR analyses revealed that the A-ring enone in WA, but not in withanone or withanolide A, was highly reactive with cysteamine and rapidly succumbed to irreversible nucleophilic addition. Mass spectrometry demonstrated direct covalent binding of WA at cysteine-303 of β-tubulin in MCF-7 cells. Molecular docking studies indicated that the WA-binding pocket was located on the surface of the β-tubulin and characterized by a hydrophobic floor, a hydrophobic wall, and a charge-balanced hydrophilic entrance. These results provide novel insights into the mechanism of anticancer effect of WA. This work was supported by the grants RO1 CA142604 and P30 CA047904 awarded by the National Cancer Institute.

Citation Format: Shivendra V. Singh, Marie Lue Antony, Joomin Lee, Eun-Ryeong Hahm, Su-Hyeong Kim, Guillermo Romero, Adam I. Marcus, Zhen Yang, Vandana Kumari, Xinhua Ji, Courtney L. Vowell, Peter Wipf, Guy T. Uechi, Nathan A. Yates. Withaferin A downregulates tubulins and covalently binds β-tubulin at cysteine-303 in human breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 228. doi:10.1158/1538-7445.AM2014-228

Abstract 227: Estrogen receptor-α and tumor initiating cells are novel targets of diallyl trisulfide in breast cancer cells

Epidemiological studies suggest a protective role for Allium vegetables, such as garlic, against breast and other cancers. Diallyl trisulfide (DATS) is a promising oil-soluble anticancer metabolite generated after cutting or chewing of Allium vegetables. We have shown previously that DATS inhibits viability of human breast cancer cells (MCF-7 and MDA-MB-231) and a cell line derived from spontaneously developed tumor of a mouse mammary tumor virus-neu mouse by causing apoptosis induction. We also found that a non-tumorigenic normal human mammary epithelial cell line (MCF-10A) is resistant to cell death induction by DATS. Studies by others have demonstrated in vivo efficacy of DATS against MCF-7 xenografts in nude mice. The present study builds upon these observations and identifies novel targets of DATS in breast cancer cells. MCF-7 and T47D cells exposed to DATS exhibited downregulation of estrogen receptor-α (ER-α) protein, which peaked between 12 and 24 h post-treatment. Diallyl sulfide and diallyl disulfide analogs were relatively less effective in suppressing protein level of ER-α compared with DATS. The 17β-estradiol (E2)-induced expression of pS2, an ER-α target gene product, was also decreased in the presence of DATS. Downregulation of ER-α protein expression resulting from DATS treatment was accompanied by a decrease in nuclear level of ER-α, suppression of ER-α mRNA, and inhibition of ERE2e1b-luciferase reporter activity. Moreover, apoptotic cell death induced by DATS was partially but statistically significantly attenuated in the presence of E2 in MCF-7 cells as well as by overexpression of ER-α in MDA-MB-231 cells. DATS treatment inhibited breast cancer stem cell (bCSC) population as evidenced by flow cytometric analysis of CD44high/CD24low/epithelial specific antigen positive population, aldehyde dehydrogenase 1 activity, and mammosphere frequency in MCF-7 and SUM159 cells. Inhibition of bCSC by treatment with DATS was associated with downregulation of EZH2 and Kruppel-like factor 4 proteins in both MCF-7 and SUM159 cells. In conclusion, the present study identifies ER-α and bCSC as novel targets of DATS in mammary cancer cells. This study was supported by the grant RO1 CA113363-09 awarded by the National Cancer Institute.

Citation Format: Eun-Ryeong Hahm, Su-Hyeong Kim, Shivendra V. Singh. Estrogen receptor-α and tumor initiating cells are novel targets of diallyl trisulfide in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 227. doi:10.1158/1538-7445.AM2014-227

Abstract 225: Overexpression of truncated Ron augments benzyl isothiocyanate-induced apoptosis in human breast cancer cells

Phytochemicals from edible plants remain attractive for prevention of breast cancer, which is a leading cause of cancer-related mortality in women worldwide. We have shown previously that benzyl isothiocyanate (BITC), a small-molecule found in edible cruciferous vegetables such as garden cress, confers significant protection against mammary cancer development in MMTV-neu transgenic mice. BITC-mediated prevention of mammary carcinogenesis in MMTV-neu mice in vivo is associated with tumor cell apoptosis induction and elimination of breast cancer stem cells (bCSC). In cultured human breast cancer cells, BITC-induced apoptosis is accompanied by activation of multidomain proapoptotic protein Bax whereas inhibition of bCSC self-renewal is significantly attenuated by overexpression of truncated Ron (recepteur d’origine nantais) tyrosine kinase. Ron expression is very low in normal human breast epithelium but its overexpression has been reported in about 50% of primary breast cancers. In addition, mammary-specific overexpression of wild-type Ron as well as its constitutively active form induces highly metastatic breast tumors in mice. The present study was undertaken to study the role of truncated Ron (sfRon) in BITC-induced apoptosis using MCF-7 and MDA-MB-361 human breast cancer cells. Overexpression of sfRon resulted in statistically significant augmentation of BITC-induced apoptotic cell death in both cell lines as judged by flow cytometry after staining with Annexin V and propidium iodide, analysis of histone associated DNA fragment release into the cytosol, and/or cell proliferation assay. On the other hand, sfRon overexpressing MCF-7 cells were resistant to BITC-mediated G2/M phase cell cycle arrest when compared with parental cells. Increased apoptosis following BITC treatment in sfRon overexpressing cells was due to enhanced activation of Bax and/or Bak. Taken together, these findings indicate that overexpression of sfRon sensitizes human breast cancer cells to BITC-induced apoptosis. This investigation was supported by the NCI grant CA129347-06.

Citation Format: Anuradha Sehrawat, Shivendra V. Singh. Overexpression of truncated Ron augments benzyl isothiocyanate-induced apoptosis in human breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 225. doi:10.1158/1538-7445.AM2014-225

Abstract 224: The role of Bmi-1 in benzyl isothiocyanate-mediated suppression of breast cancer stem cell self-renewal

We have shown previously that benzyl isothiocyanate (BITC), a nontoxic small-molecule constituent of edible cruciferous vegetables (eg, garden cress) inhibits breast cancer stem cells (bCSC) in vitro and in vivo but the underlying mechanisms are not fully understood. Bmi-1 is a member of the polycomb group family of proteins that function in the epigenetic silencing of genes governing self-renewal, differentiation, and proliferation. The present study was undertaken to investigate the role of Bmi-1 in BITC-mediated inhibition of bCSC. BITC treatment downregulated protein level of Bmi-1 in cultured human breast cancer cells (MCF-7, SUM159 and MDA-MB-231), and in MDA-MB-231 xenografts in vivo. Ectopic expression of Bmi-1 alone was sufficient to drive stemness in MCF-7 cells. In addition, Bmi-1 overexpression in MCF-7 cells conferred marked protection against BITC-mediated inhibition of bCSC as evidenced by mammosphere frequency and aldehyde dehydrogenase 1 (ALDH1) activity. Consistent with these observations, silencing of Bmi-1 in SUM159 cells remarkably reduced the portion of bCSC. Apoptosis induced by BITC was also partially attenuated by overexpression of Bmi-1 in MCF-7 cells but its silencing had no effect on BITC-induced apoptosis in SUM159 cells. Previous studies have shown that miRNA128 inhibits cell proliferation and self-renewal by direct regulation of Bmi-1. BITC treatment modestly but statistically significantly increased the expression of miRNA128 in both MCF-7 and SUM159 cells. Inhibition of miRNA128 increased the mammosphere formation in MCF-7 and SUM159 cells and partially attenuated BITC-mediated inhibition of mammosphere formation. These observations led us to conclude that Bmi-1 is a novel target of BITC-mediated inhibition of bCSC. This study was supported by the grant RO1 CA129347 awarded by the National Cancer Institute.

Citation Format: Su-Hyeong Kim, Shivendra V. Singh. The role of Bmi-1 in benzyl isothiocyanate-mediated suppression of breast cancer stem cell self-renewal. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 224. doi:10.1158/1538-7445.AM2014-224

Honokiol activates reactive oxygen species-mediated cytoprotective autophagy in human prostate cancer cells

BACKGROUND

Honokiol (HNK), derived from the bark of an oriental medicinal plant (Magnolia officinalis), is a promising anticancer agent with preclinical in vitro (PC-3 and LNCaP cells) and in vivo (PC-3 xenografts) efficacy against prostate cancer. However, the mechanisms affecting anticancer response to HNK are not fully understood.

METHODS

Human (androgen-independent PC-3 and androgen-responsive LNCaP) and murine (Myc-CaP) prostate cancer cells, and PC-3 tumor xenografts were used for various assays. Autophagy was assessed by transmission electron microscopy, immunofluorescence (LC3 puncta), and immunoblotting (LC3BII detection). Cell viability was determined by trypan blue assay. Apoptosis was quantitated by DNA fragmentation detection and Annexin V/propidium iodide assay. Reactive oxygen species (ROS) were detected by electron paramagnetic resonance spectrometry and flow cytometric/microscopic analysis of MitoSOX red fluorescence.

RESULTS

Exposure of PC-3, LNCaP, and Myc-CaP cells to pharmacologic doses of HNK resulted in autophagy induction. The PC-3 tumor xenografts from HNK-treated mice contained higher levels of LC3BII protein compared with control tumors. Cell viability inhibition and apoptosis induction resulting from HNK exposure were significantly augmented by pharmacological inhibition of autophagy using 3-methyladenine as well as RNA interference of autophagy regulator ATG5. HNK-mediated increase in levels of LC3BII protein was partially but markedly diminished in the presence of antioxidants, including N-acetylcysteine, polyethylene glycol-conjugated (PEG)-superoxide dismutase, and PEG-catalase. On the other hand, antioxidants had no impact on HNK-induced apoptosis.

CONCLUSIONS

In conclusion, the present study demonstrates, for the first time, that HNK induces ROS-mediated cytoprotective autophagy in prostate cancer cells.

Mammary cancer chemoprevention by withaferin A is accompanied by in vivo suppression of self-renewal of cancer stem cells

Current dogma favors elimination of therapy-resistant cancer stem cells for chemoprevention of breast cancer. We showed recently that mammary cancer development in a transgenic mouse model (mouse mammary tumor virus-neu; MMTV-neu) was inhibited significantly upon treatment with withaferin A (WA), a steroidal lactone derived from a medicinal plant. Herein, we demonstrate that the mammary cancer prevention by WA is accompanied by in vivo suppression of breast cancer stem cells (bCSC). In vitro mammosphere formation was dose-dependently inhibited by WA treatment in MCF-7 and SUM159 human breast cancer cells. Other markers of bCSC, including aldehyde dehydrogenase 1 (ALDH1) activity and CD44(high)/CD24(low)/epithelial-specific antigen-positive (ESA+) fraction, were also decreased significantly in the presence of plasma achievable doses of WA. However, WA exposure resulted in cell line-specific changes in Oct4, SOX-2, and Nanog mRNA expression. WA administration to MMTV-neu mice (0.1 mg/mouse, 3 times/week for 28 weeks) resulted in inhibition of mammosphere number and ALDH1 activity in vivo. Mechanistic studies revealed that although urokinase-type plasminogen activator receptor overexpression conferred partial protection against bCSC inhibition by WA, Notch4 was largely dispensable for this response. WA treatment also resulted in sustained (MCF-7) or transient (SUM159) downregulation of Bmi-1 (B-cell-specific Moloney murine leukemia virus insertion region-1) protein. Ectopic expression of Bmi-1 conferred partial but significant protection against ALDH1 activity inhibition by WA. Interestingly, WA treatment caused induction of Kruppel-like factor 4 (KLF4) and its knockdown augmented bCSC inhibition by WA. In conclusion, this study shows in vivo effectiveness of WA against bCSC.

Mechanistic elucidation of the antitumor properties of withaferin a in breast cancer

Withaferin A (WFA) is a steroidal lactone with antitumor effects manifested at multiple levels that are mechanistically obscure. Using a phospho-kinase screening array, we discovered that WFA activated phosphorylation of the S6 kinase RSK (ribosomal S6 kinase) in breast cancer cells. Pursuing this observation, we defined activation of extracellular signal-regulated kinase (ERK)-RSK and ETS-like transcription factor 1 (Elk1)-CHOP (C-EBP homologous protein) kinase pathways in upregulating transcription of the death receptor 5 (DR5). Through this route, WFA acted as an effective DR5 activator capable of potentiating the biologic effects of celecoxib, etoposide, and TRAIL. Accordingly, WFA treatment inhibited breast tumor formation in xenograft and mouse mammary tumor virus (MMTV)-neu mouse models in a manner associated with activation of the ERK/RSK axis, DR5 upregulation, and elevated nuclear accumulation of Elk1 and CHOP. Together, our results offer mechanistic insight into how WFA inhibits breast tumor growth.

Honokiol inhibits androgen receptor activity in prostate cancer cells

BACKGROUND

We have shown previously that honokiol (HNK), a bioactive component of the medicinal plant Magnolia officinalis, inhibits growth of human prostate cancer cells in vitro and in vivo. However, the effect of HNK on androgen receptor (AR) signaling has not been studied.

METHODS

LNCaP, C4-2, and TRAMP-C1 cells were used for various assays. Trypan blue dye exclusion assay or clonogenic assay was performed for determination of cell viability. The effects of HNK and/or its analogs on protein levels of AR and its target gene product prostate specific antigen (PSA) were determined by western blotting. RNA interference of p53 was achieved by transient transfection. Reverse transcription-polymerase chain reaction was performed for mRNA expression of AR. Nuclear level of AR was visualized by microscopy. Apoptosis was quantified by DNA fragmentation assay or flow cytometry after Annexin V-propidium iodide staining.

RESULTS

HNK and its dichloroacetate analog (HDCA) were relatively more effective in suppressing cell viability and AR protein level than honokiol epoxide or biseugenol. Nuclear translocation of AR stimulated by a synthetic androgen (R1881) was markedly suppressed in the presence of HNK. Downregulation of AR protein resulting from HNK exposure was attributable to transcriptional repression as well as proteasomal degradation. HNK-mediated suppression of AR protein was maintained in LNCaP cells after knockdown of p53 protein. HNK-induced apoptosis was not affected by R1881 treatment.

CONCLUSIONS

The present study demonstrates, for the first time, that HNK inhibits activity of AR in prostate cancer cells regardless of the p53 status.

Autophagy fails to alter withaferin A-mediated lethality in human breast cancer cells

We have shown previously that withaferin A (WA), which is a highly promising anticancer constituent of Ayurvedic medicine plant Withania somnifera, inhibits viability of cultured breast cancer cells in association with reactive oxygen species (ROS)-dependent apoptosis induction. Because ROS production is implicated in induction of autophagy, which is an evolutionary conserved process for bulk degradation of cellular components including organelles (e.g., mitochondria) and considered a valid cancer chemotherapeutic target, we questioned whether WA treatment resulted in autophagy induction. Indeed exposure of MDA-MB-231 and MCF-7 human breast cancer cells as well as a spontaneously immortalized and non-tumorigenic normal human mammary epithelial cell line (MCF-10A) to pharmacologic concentration of WA resulted in autophagy as evidenced by transmission electron microscopy, processing of microtubuleassociated protein 1 light chain 3 isoform B, and/or acridine orange staining. Inhibition of MDA-MB-231 xenograft growth in vivo by WA administration was also associated with a significant increase in level of LC3 protein in the tumor. However, WA-mediated inhibition of MDA-MB-231 and MCF-7 cell viability was not compromised either by pharmacological suppression of autophagy using 3-methyl adenine or genetic repression of autophagy by RNA interference of Atg5, a critical component of the autophagic machinery. Finally, Beclin1 was dispensable for WA-mediated autophagy as well as inhibition of MDA-MB-231 cell viability. Based on these observations we conclude that autophagy induction fails to have any meaningful impact on WA-mediated lethality in breast cancer cells, which may be a therapeutic advantage because autophagy serves to protect against apoptosis by several anticancer agents.

Diallyl trisulfide inhibits estrogen receptor-α activity in human breast cancer cells

Organosulfur compounds from garlic effectively inhibit growth of transplanted as well as spontaneous cancers in preclinical animal models without any adverse side effects. However, the mechanisms underlying anticancer effect of this class of compounds are not fully understood. This study reports, for the first time, that garlic organosulfide diallyl trisulfide (DATS) inhibits estrogen receptor-α (ER-α) activity in human breast cancer cells. Exposure of MCF-7 and T47D cells to DATS resulted in downregulation of ER-α protein, which peaked between 12- and 24-h post-treatment. DATS was relatively more effective in suppressing ER-α protein expression compared with its mono and disulfide analogs. The 17β-estradiol (E2)-induced expression of pS2 and cyclin D1, ER-α target gene products, was also decreased in the presence of DATS. Downregulation of ER-α protein expression resulting from DATS treatment was accompanied by a decrease in nuclear levels of ER-α protein, ER-α mRNA suppression, and inhibition of ERE2e1b-luciferase reporter activity. DATS-mediated inhibition of cell viability and apoptosis induction were not affected in the presence of E2. In agreement with these results, ectopic expression of ER-α in MDA-MB-231 cell line failed to confer any protection against cell proliferation inhibition or apoptosis induction resulting from DATS exposure. DATS treatment caused a decrease in protein levels of peptidyl-prolyl cis-trans isomerase (Pin1), and overexpression of Pin1 partially attenuated ER-α downregulation by DATS. DATS-induced apoptosis was modestly but significantly augmented by overexpression of Pin1. In conclusion, this study identifies ER-α as a novel target of DATS in mammary cancer cells.

In vitro and in vivo effects of phenethyl isothiocyanate treatment on vimentin protein expression in cancer cells

We have shown previously that cancer prevention by cruciferous vegetable constituent phenethyl isothiocyanate (PEITC) in a transgenic mouse model of prostate cancer is associated with induction of E-cadherin protein expression. Because suppression of E-cadherin protein concomitant with induction of mesenchymal markers (e.g., vimentin) is a biochemical hallmark of epithelial-mesenchymal transition, a process implicated in cancer metastasis, we hypothesized that PEITC treatment was likely to suppress vimentin protein expression. Contrary to this prediction, exposure of human breast (MDA-MB-231) and prostate cancer cells (PC-3 and DU145) to PEITC resulted in a dose-dependent increase in vimentin protein level, which was observed as early as 6 h posttreatment and persisted for the duration of the experiment (24 h). RNA interference of vimentin resulted in a modest augmentation of PEITC-mediated inhibition of MDA-MB-231 and PC-3 cell migration as well as cell viability. Furthermore, the PEITC-induced apoptosis was moderately increased upon siRNA knockdown of vimentin protein in MDA-MB-231 and PC-3 cells. To our surprise, PEITC treatment caused a marked decrease in vimentin protein expression in breast and prostate carcinoma in vivo in transgenic mouse models, although the difference was statistically significant only in the breast carcinomas. The present study highlights the importance of in vivo correlative studies for validation of the in vitro mechanistic observations.

Perception of stigma towards TB among patients on DOTS & patients attending general OPD in Delhi

BACKGROUND

In India, Tuberculosis (TB) continues to be a public health problem. One of the key reasons for it is the stigma associated with the disease which affects the treatment seeking behaviour and hence the outcome.

OBJECTIVES

To assess the perceived and enacted stigma among TB patients and perceptions of other patients related to TB in Central Delhi.

METHODS

A cross-sectional study conducted in urban field practice area of a medical college of Delhi, using a pre-designed questionnaire containing items for assessment of stigma being faced by a TB patient in family, social life and workplace. It also contained questions pertaining to reaction of patients from general OPD to a family member who develops TB.

RESULTS

A total of 100 patients on DOTS and 200 patients from general OPD were interviewed. There were 21 patients who reported to have delayed treatment seeking due to stigma. Nearly one third patients (n=34; 34%) noted negative changes in the behaviour of their family members towards them while 40% were isolated on being diagnosed with the disease. Out of the 36 employed TB patients, 65.5% (n=23) experienced negative change in the behaviour of their colleagues. In general OPD patients, significantly higher proportion of female patients said that they would not disclose the disease status of a family member suffering from TB to their neighbours (p<0.001).

CONCLUSIONS

Perception of stigmatizing effect of Tuberculosis was high both amongst TB and other patients. Behaviour Change Communication (BCC) strategies are needed to address the effects of stigma like delayed treatment seeking.

Expression profiles of different cytokine genes in peripheral blood mononuclear cells of goats infected experimentally with native strain of Mycobacterium avium subsp. paratuberculosis

Paratuberculosis (ParaTB), caused by Mycobacterium avium subspecies paratuberculosis (MAP) is a chronic enteritis of ruminants and may contribute to Crohn's disease in humans. Key features of host immunity to MAP infection include an early pro-inflammatory (Th1-like) response that eventually gives way to a predominant anti-inflammatory (Th2-like) response. Many studies have been conducted to understand the underlying mechanism of misdirected host immune response, however, these studies mainly focused on cattle. The present study is the first attempt to test the hypothesis of shift in Th1 to Th2 like responses during the progression of ParaTB in caprine species (small ruminant). Ten healthy male kids (<6 months old) of the same breed were selected for this study. Of the 10 kids, 6 were experimentally infected with native strain (S5) of MAP ("Indian Bison Type") and the remaining 4 kids were control. Kids were monitored for a period of 12 months post infection (MPI) and were tested for establishment of infection. Expression levels of IFNG, IL2, IL12, IL4, and IL10 genes were estimated before infection and at 4, 8, and 12 MPI in stimulated peripheral blood mononuclear cells (PBMCs) of infected and control kids. The study demonstrated the expression of IFNG and IL2 as classic Th1-like pro-inflammatory signatures; whereas, IL10 exhibited itself as classical Th2-like signature. The study also reports unexpected lowered expression of the IL12 gene simultaneously with increased expression of IFNG, lowered expression of the IL2 gene (compared to IFNG), and suppressed expression of the IL4.

Growth arrest by the antitumor steroidal lactone withaferin A in human breast cancer cells is associated with down-regulation and covalent binding at cysteine 303 of β-tubulin

Withaferin A (WA), a C5,C6-epoxy steroidal lactone derived from a medicinal plant (Withania somnifera), inhibits growth of human breast cancer cells in vitro and in vivo and prevents mammary cancer development in a transgenic mouse model. However, the mechanisms underlying the anticancer effect of WA are not fully understood. Herein, we report that tubulin is a novel target of WA-mediated growth arrest in human breast cancer cells. The G2 and mitotic arrest resulting from WA exposure in MCF-7, SUM159, and SK-BR-3 cells was associated with a marked decrease in protein levels of β-tubulin. These effects were not observed with the naturally occurring C6,C7-epoxy analogs of WA (withanone and withanolide A). A non-tumorigenic normal mammary epithelial cell line (MCF-10A) was markedly more resistant to mitotic arrest by WA compared with breast cancer cells. Vehicle-treated control cells exhibited a normal bipolar spindle with chromosomes aligned along the metaphase plate. In contrast, WA treatment led to a severe disruption of normal spindle morphology. NMR analyses revealed that the A-ring enone in WA, but not in withanone or withanolide A, was highly reactive with cysteamine and rapidly succumbed to irreversible nucleophilic addition. Mass spectrometry demonstrated direct covalent binding of WA to Cys(303) of β-tubulin in MCF-7 cells. Molecular docking indicated that the WA-binding pocket is located on the surface of β-tubulin and characterized by a hydrophobic floor, a hydrophobic wall, and a charge-balanced hydrophilic entrance. These results provide novel insights into the mechanism of growth arrest by WA in breast cancer cells.

Withaferin A inhibits experimental epithelial-mesenchymal transition in MCF-10A cells and suppresses vimentin protein level in vivo in breast tumors

We have shown previously that withaferin A (WA), a bioactive component of the medicinal plant Withania somnifera, inhibits growth of cultured and xenografted human breast cancer cells and prevents breast cancer development and pulmonary metastasis incidence in a transgenic mouse model. The present study was undertaken to determine if the anticancer effect of WA involved inhibition of epithelial-mesenchymal transition (EMT). Experimental EMT induced by exposure of MCF-10A cells to tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β) was partially reversed by treatment with WA but not by its structural analogs withanone or withanolide A. Combined TNF-α and TGF-β treatments conferred partial protection against MCF-10A cell migration inhibition by WA. Inhibition of TNF-α and TGF-β-induced MCF-10A cell migration by WA exposure was modestly attenuated by knockdown of E-cadherin protein. MCF-7 and MDA-MB-231 cells exposed to WA exhibited sustained (MCF-7) or transient (MDA-MB-231) induction of E-cadherin protein. On the other hand, the level of vimentin protein was increased markedly after 24 h treatment of MDA-MB-231 cells with WA. WA-induced apoptosis was not affected by vimentin protein knockdown in MDA-MB-231 cells. Protein level of vimentin was significantly lower in the MDA-MB-231 xenografts as well as in MMTV-neu tumors from WA-treated mice compared with controls. The major conclusions of the present study are that (a) WA treatment inhibits experimental EMT in MCF-10A cells, and (b) mammary cancer growth inhibition by WA administration is associated with suppression of vimentin protein expression in vivo.

Phenethyl isothiocyanate inhibits proliferation and induces apoptosis in pancreatic cancer cells in vitro and in a MIAPaca2 xenograft animal model

Pancreatic cancer is often diagnosed at an advanced stage and it has a poor prognosis that points to an increased need to develop effective chemoprevention strategies for this disease. We examined the ability of phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate found in cruciferous vegetables, to inhibit the growth of pancreatic cancer cells in vitro and in a MIAPaca2 xenograft animal model. Exposure to PEITC inhibited pancreatic cancer cell growth in a dose-dependent manner, with an IC50 of approximately 7 μmol/L. PEITC treatment induced G2/M phase cell cycle arrest, downregulated the antiapoptotic proteins Bcl-2 and Bcl-XL, upregulated the proapoptotic protein Bak, and suppressed Notch 1 and 2 levels. In addition, treatment with PEITC induced cleavage of poly-(ADP-ribose) polymerase and led to increased cytoplasmic histone-associated DNA fragmentation and subdiploid (apoptotic) fraction in pancreatic cancer cells. Oral administration of PEITC suppressed the growth of pancreatic cancer cells in a MIAPaca2 xenograft animal model. Our data show that PEITC exerts its inhibitory effect on pancreatic cancer cells through several mechanisms, including G2/M phase cell cycle arrest and induction of apoptosis, and supports further investigation of PEITC as a chemopreventive agent for pancreatic cancer.

Sodium butyrate induces DRP1-mediated mitochondrial fusion and apoptosis in human colorectal cancer cells

Sodium butyrate (NaBt) is the byproduct of anaerobic microbial fermentation inside the gastro-intestinal tract that could reach up to 20mM, and has been shown to inhibit the growth of various cancers. Herein, we evaluated its effect on mitochondrial fusion and associated induction of apoptosis in colorectal cancer cells (CRC). NaBt treatment at physiological (1-5mM) concentrations for 12 and 24h decreased the cell viability and induced G2-M phase cell cycle arrest in HCT116 (12h) and SW480 human CRC cells. This cell cycle arrest was associated with mitochondria-mediated apoptosis accompanied by a decrease in survivin and Bcl-2 expression, and generation of reactive oxygen species (ROS). Furthermore, NaBt treatment resulted in a significant decrease in the mitochondrial mass which is an indicator of mitochondrial fusion. Level of dynamin-related protein 1 (DRP1), a key regulator of mitochondrial fission and fusion where its up-regulation correlates with fission, was found to be decreased in CRC cells. Further, at early treatment time, DRP1 down-regulation was noticed in mitochondria which later became drastically reduced in both mitochondria as well as cytosol. DRP1 is activated by cyclin B1-CDK1 complex by its ser616 phosphorylation in which both cyclin B1-CDK1 complex and phospho-DRP1 (ser616) were strongly reduced by NaBt treatment. DRP1 was observed to be regulated by apoptosis as pan-caspase inhibitor showing rescue from NaBt-induced apoptosis also caused the reversal of DRP1 to the normal level as in control proliferating cells. Together, these findings suggest that NaBt can modulate mitochondrial fission and fusion by regulating the level of DRP1 and induce cell cycle arrest and apoptosis in human CRC cells.

Functional relevance of D,L-sulforaphane-mediated induction of vimentin and plasminogen activator inhibitor-1 in human prostate cancer cells

PURPOSE

D,L-Sulforaphane (SFN) is a promising chemopreventive agent with in vivo efficacy against prostate cancer in experimental rodents. This study was undertaken to determine the role of vimentin and plasminogen activator inhibitor-1 (PAI-1) in anticancer effects of SFN.

METHODS

Effect of SFN on levels of different proteins was determined by Western blotting or immunofluorescence microscopy. RNA interference of vimentin and PAI-1 was achieved by transient transfection. Apoptosis was quantified by flow cytometry. Transwell chambers were used to determine cell migration.

RESULTS

Exposure of PC-3 and DU145 human prostate cancer cells to SFN resulted in induction of vimentin protein, which was accompanied by down-regulation of E-cadherin protein expression. The SFN-mediated induction of vimentin was also observed in a normal human prostate epithelial cell line. RNA interference of vimentin did not have any appreciable effect on early or late apoptosis resulting from SFN exposure. On the other hand, SFN-mediated inhibition of PC-3 and DU145 cell migration was significantly augmented by knockdown of the vimentin protein. Knockdown of vimentin itself was inhibitory against cell migration. The SFN-treated cells also exhibited induction of PAI-1, which is an endogenous inhibitor of urokinase-type plasminogen activator system. Similar to vimentin, PAI-1 knockdown resulted in a modest augmentation of PC-3 cell migration inhibition by SFN. Tumors from SFN-treated transgenic adenocarcinoma of mouse prostate mice showed a 1.7-fold increase in vimentin protein level compared with control tumors.

CONCLUSION

The present study indicates that vimentin and PAI-1 inductions confer modest protection against SFN-mediated inhibition of prostate cancer cell migration.

Molecular targets and mechanisms of cancer prevention and treatment by withaferin a, a naturally occurring steroidal lactone

The plants used in Ayurvedic medicine, which has been practiced in India for thousands of years for the treatment of a variety of disorders, are rich in chemicals potentially useful for prevention and treatment of cancer. Withania somnifera (commonly known as Ashwagandha in Ayurvedic medicine) is one such medicinal plant whose anticancer value was realized over four decades ago after isolation of a crystalline steroidal compound (withaferin A) from the leaves of this shrub. The root and leaf extracts of W. somnifera are shown to confer protection against chemically-induced cancers in experimental rodents, and retard tumor xenograft growth in athymic mice. Anticancer effect of W. somnifera is generally attributable to steroidal lactones collectively referred to as withanolides. Withaferin A (WA) appears most active against cancer among structurally divergent withanolides isolated from the root or leaf of W. somnifera. Cancer-protective role for WA has now been established using chemically-induced and oncogene-driven rodent cancer models. This review summarizes the key in vivo preclinical studies demonstrating anticancer effects of WA. Molecular targets and mechanisms likely contributing to the anticancer effects of WA are also discussed. Finally, challenges in clinical development of WA for the prevention and treatment of cancer are highlighted.

Role of mitogen-activated protein kinases and Mcl-1 in apoptosis induction by withaferin A in human breast cancer cells

Withaferin A (WA), a bioactive constituent of Ayurvedic medicine plant Withania somnifera, is a potent apoptosis inducer in cancer cells but the mechanism of cell death induction is not fully characterized. The present study was undertaken to determine the role of mitogen-activated protein kinases (MAPK), including c-jun NH2 -terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 MAPK, and anti-apoptotic protein myeloid cell leukemia-1 (Mcl-1) in regulation of WA-induced apoptosis using human breast cancer cells. Exposure of MCF-7 (estrogen responsive) and SUM159 (triple negative) human breast cancer cells to WA resulted in increased phosphorylation of ERK, JNK, and p38 MAPK, but these effects were relatively more pronounced in the former cell line than in SUM159. Overexpression of manganese-superoxide dismutase conferred partial protection against WA-mediated hyperphosphorylation of ERK, but not JNK or p38 MAPK. Cell death resulting from WA treatment in MCF-7 cells was significantly augmented by pharmacological inhibition of ERK and p38 MAPK. Interestingly, the WA-induced apoptosis in MCF-7 cells was partially but significantly blocked in the presence of a JNK-specific inhibitor. Pharmacological inhibition of ERK or JNK had no effect on WA-induced apoptosis in SUM159 cells. The WA-treated cells exhibited induction of long and short forms of Mcl-1. RNA interference of Mcl-1 alone triggered apoptosis. Furthermore, the WA-induced cell death in MCF-7 cells was modestly but significantly augmented by knockdown of the Mcl-1 protein. These observations indicate that: MAPK have cell line-specific role in cell death by WA, and Mcl-1 induction confers modest protection against WA-induced apoptosis.

Cephalometric evaluation of mandibular advancement at different horizontal jaw positions in obstructive sleep apnoea patients: a pilot study

BACKGROUND

The aim of this study was to comparatively evaluate the efficacy of the mandibular advancement device (MAD) at 50% (P2) and 75% (P3) of maximum mandibular advancement, relative to maximum intercuspation (P1) subjectively and objectively.

METHODS

Eighteen subjects previously diagnosed with obstructive sleep apnoea (OSA) were selected for the study. ESS score, VAS score, soft palate angle, MP-H distance, S-H distance, a C4 -H distance, a Pu -p Pu distance and total pharyngeal area were calculated at P1, P2 and P3 positions with the help of an adjustable MAD. The results were statistically analysed.

RESULTS

ESS score, VAS score, soft palate angle, MP-H distance, S-H distance and radius of curvature of airway at P2 and P3 were significantly lower compared to P1, but there was no significant difference between P2 and P3.

CONCLUSIONS

The MAD produced significant improvement in objective signs and subjective symptoms at both 50% and 75% of the maximum mandibular protrusion positions at comparable comfort levels. Therefore, MAD may be given at 50% of maximum advancement in order to reduce dental or temporomandibular joint disturbances.