chandra prasad - Academia.edu (original) (raw)

Papers by chandra prasad

Research paper thumbnail of Dual mechanisms of action of the RNA-binding protein HuR explains its regulatory effect on melanoma cell migration

Translational Research, 2016

Research paper thumbnail of Potent growth suppressive activity of curcumin in human breast cancer cells: Modulation of Wnt/beta-catenin signaling

Chemico-biological interactions, Jan 7, 2009

Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta... more Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta-catenin driven downstream targets-c-Myc and cyclin D1 is associated with development of breast cancer. The objective of our study was to determine if curcumin could modulate the key elements of Wnt pathway in breast cancer cells; an effect that might underscore its usefulness for chemoprevention/treatment of this malignancy. Curcumin showed a cytotoxic effect on MCF-7 cells with 50% inhibitory concentration (IC(50)) of 35microM; while IC(50) for MDA-MB-231 cells was 30microM. Treatment with low cytostatic dose of 20microM curcumin showed G(2)/M arrest in both breast cancer cells. The effect of curcumin (20microM) treatment on expression of Wnt/beta-catenin pathway components in breast cancer cells (MCF-7 and MDA-MB-231) was analyzed by immunofluorescence and Western blotting. Curcumin was found to effectively inhibit the expression of several Wnt/beta-catenin pathway components-dishevel...

Research paper thumbnail of Bcl-2 and p53 expressions in Indian women with complete hydatidiform mole

Singapore medical journal, 2011

Hydatidiform moles have a high incidence rate in Asian countries like India. The molecular pathwa... more Hydatidiform moles have a high incidence rate in Asian countries like India. The molecular pathway leading to the pathogenesis and progression of hydatidiform moles is not yet understood. This study aimed to investigate the biological significance of Bcl-2 and p53 in complete hydatidiform moles (CHMs) as well as their influence on disease progression in the Indian population. Archival tissues from 35 patients with CHMs and 35 age-matched controls were examined for Bcl-2 and p53 expressions by immunohistochemistry. Bcl-2 was found to be immunolocalised in the cytoplasm of the syncytiotrophoblast, whereas p53 was observed in both the nucleus and cytoplasm of the syncytiotrophoblast and cytotrophoblasts. In CHMs, Bcl-2 was detected in 23 percent of patients and p53 nuclear expression, in 66 percent. A significant decrease in Bcl-2 expression was observed in CHMs (p-value is 0.015), and the down-regulation of Bcl-2 significantly correlated with higher nuclear expression of p53 (p-value ...

Research paper thumbnail of Interleukin-6 drives melanoma cell motility through p38α-MAPK-dependent up-regulation of WNT5A expression

Molecular oncology, 2014

Extensive research has demonstrated a tumor-promoting role of increased WNT5A expression in malig... more Extensive research has demonstrated a tumor-promoting role of increased WNT5A expression in malignant melanoma. However, very little light has been shed upon how WNT5A expression is up-regulated in melanoma. A potential regulator of WNT5A expression is the pro-inflammatory cytokine Interleukin (IL)-6, which shares the ability of WNT5A to increase melanoma cell invasion. Here, we investigate whether IL-6 can promote melanoma cell motility through an increased expression of WNT5A. We clearly demonstrate that the WNT5A-antagonistic peptide Box5 could inhibit IL-6-induced melanoma cell migration and invasion. Furthermore, IL-6 stimulation of the human melanoma cell lines HTB63 and A375 increased the expression of WNT5A in a dose-dependent manner. To identify the signaling mechanism responsible for this up-regulation, we explored the involvement of the three main signals induced by IL-6; STAT3, Akt and ERK 1/2. Of these, only STAT3 was activated by IL-6 in the melanoma cell lines tested....

Research paper thumbnail of Promoter hypermethylation of p16INK4A, p14ARF, CyclinD2 and Slit2 in serum and tumor DNA from breast cancer patients

Life Sciences, 2007

Epigenetic mechanisms such as DNA methylation play important role in cancer. Epigenetic alteratio... more Epigenetic mechanisms such as DNA methylation play important role in cancer. Epigenetic alterations involved in the onset and progression of breast cancer may serve as biomarkers for early detection and prediction of disease prognosis. Furthermore, using body fluids such as serum offers a non-invasive method to procure multiple samples for biomarker analyses. The aim of this study is to determine the correlation between methylation status of multiple cancer genes, p16(INK4A), p14(ARF), Cyclin D2 and Slit2 in invasive ductal carcinoma of the breast and paired serum DNA and clinicopathological parameters. Of the 36 breast cancer patients investigated, 31 (86%) tumors and 30 (83%) paired sera showed methylation of at least one of these 4 genes. Methylation frequencies varied from 27% for CyclinD2, 44% for p16(INK4A), 47% for p14(ARF) to 58% for Slit2. There was concordance between DNA methylation in tumor and paired serum DNA of each gene. This study underscores the potential utility of DNA methylation based screening of serum as a surrogate marker for tumor DNA methylation status of these genes in breast cancer. Further, expression profile of p16(INK4A) could be linked to epigenetic events, thus suggesting this pathway as a potential target for therapeutic strategies based on reversal of epigenetic silencing.

Research paper thumbnail of Wnt Signaling Pathway in Invasive Ductal Carcinoma of the Breast: Relationship between β-Catenin, Disheveled and Cyclin D1 Expression

Oncology, 2007

The Wnt/beta-catenin signaling cascade is an important signal transduction pathway in human cance... more The Wnt/beta-catenin signaling cascade is an important signal transduction pathway in human cancers. Overexpression of beta-catenin and its downstream effector, cyclin D1, is implicated in malignant transformation and acquisition of an invasive tumor phenotype. This study aimed to determine the clinical significance of Wnt/beta-catenin canonical pathway components in breast cancer. Expression of beta-catenin, dishevelled (Dvl) and cyclin D1 was examined in invasive ductal carcinomas (IDCs) of the breast by immunohistochemical analysis. Of the 98 IDCs analyzed, 30% of tumors displayed both nuclear and cytoplasmic staining of Dvl protein, while 52% showed nuclear localization. Loss of cell surface beta-catenin was observed in 66% of breast carcinomas, whereas nuclear expression was observed in 48% IDCs. Cyclin D1 overexpression was observed in 60% IDCs; 31/59 (53%) of these tumors showed nuclear expression of beta-catenin, suggesting upregulation of the canonical Wnt/beta-catenin pathway. Our study demonstrates a significant association between nuclear localization of Dvl and beta-catenin (p < 0.01, OR = 15.8). To our knowledge, this is the first study showing an association between nuclear localization of Dvl and beta-catenin in IDCs and suggests the upregulation of Wnt/beta-catenin pathway components, beta-catenin, Dvl and cyclin D1 in IDCs of the breast.

Research paper thumbnail of Clinical significance of promoter hypermethylation of RASSF1A, RARβ2, BRCA1 and HOXA5 in breast cancers of Indian patients

Research paper thumbnail of Promoter hypermethylation of TMS1, BRCA1, ERα and PRB in serum and tumor DNA of invasive ductal breast carcinoma patients

Life Sciences, 2007

Breast cancer is fast emerging as the leading cancer amongst females, especially in younger age g... more Breast cancer is fast emerging as the leading cancer amongst females, especially in younger age group in India; a large proportion of these tumors are often aggressive and ER and/or PR negative. Promoter methylation of genes involved in DNA repair and hormonal regulation may, in part, account for this behavior. To test this hypothesis methylation status of tumor suppressor genes

Research paper thumbnail of Epigenetic alterations of CDH1 and APC genes: Relationship with activation of Wnt/β-catenin Pathway in invasive ductal carcinoma of breast

Life Sciences, 2008

Activation of canonical Wnt/beta-catenin pathway in Invasive Ductal Carcinoma of Breast (IDCs) wa... more Activation of canonical Wnt/beta-catenin pathway in Invasive Ductal Carcinoma of Breast (IDCs) was recently reported from our laboratory. Herein, we analyzed promoter methylation status of CDH1 and Adenomatous polyposis coli (APC) genes in 50 IDCs and correlated with expression of E-cadherin (E-CD) and APC proteins and with activation of oncogenic Wnt/beta-catenin signaling pathway components, Dvl, beta-catenin and CyclinD1. Further, Wnt/beta-catenin driven epithelial mesenchymal transition (EMT) was investigated by correlating the expression of Dvl, beta-catenin and CyclinD1 with vimentin expression in these IDCs. Promoter hypermethylation was observed in 25/50 (50%) IDCs for CDH1 and in 11/50 (22%) tumors for APC, associated with loss of expression of E-CD and APC proteins; concordant hypermethylation of these genes was observed in paired patients' sera. Further, 57% of tumors harboring CDH1 methylation and 50% tumors harboring the methylated APC gene showed nuclear localization of beta-catenin, suggesting activation of the canonical Wnt/beta-catenin pathway. Our study demonstrates significant association between vimentin expression and nuclear beta-catenin (p=0.001; Odds ratio (OR)=25.6) and Dvl (p=0.023; OR=8.0), suggesting that EMT may be driven by Wnt/beta-catenin activation in IDCs. In conclusion, we demonstrate correlation of CDH1 and APC promoter methylation with loss of E-CD and APC proteins and with activation of Wnt/beta-catenin signaling pathway. Association of nuclear Dvl and beta-catenin with vimentin expression suggests the importance of Wnt/beta-catenin pathway driven EMT in IDCs. The concordance between CDH1 and APC methylation in IDCs and paired circulating DNA underscores the utility of serum DNA as a non-invasive tool for methylation analysis in IDC patients.

Research paper thumbnail of Potent growth suppressive activity of curcumin in human breast cancer cells: Modulation of Wnt/β-catenin signaling

Chemico-Biological Interactions, 2009

Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta... more Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta-catenin driven downstream targets-c-Myc and cyclin D1 is associated with development of breast cancer. The objective of our study was to determine if curcumin could modulate the key elements of Wnt pathway in breast cancer cells; an effect that might underscore its usefulness for chemoprevention/treatment of this malignancy. Curcumin showed a cytotoxic effect on MCF-7 cells with 50% inhibitory concentration (IC(50)) of 35microM; while IC(50) for MDA-MB-231 cells was 30microM. Treatment with low cytostatic dose of 20microM curcumin showed G(2)/M arrest in both breast cancer cells. The effect of curcumin (20microM) treatment on expression of Wnt/beta-catenin pathway components in breast cancer cells (MCF-7 and MDA-MB-231) was analyzed by immunofluorescence and Western blotting. Curcumin was found to effectively inhibit the expression of several Wnt/beta-catenin pathway components-disheveled, beta-catenin, cyclin D1 and slug in both MCF-7 and MDA-MB-231. Immunofluorescence analysis showed that curcumin markedly reduced the nuclear expression of disheveled and beta-catenin proteins. Further, the protein levels of the positively regulated beta-catenin targets-cyclin D1 and slug, were downregulated by curcumin treatment. The expression levels of two integral proteins of Wnt signaling, GSK3beta and E-cadherin were also altered by curcumin treatment. In conclusion, our data demonstrated that the efficacy of curcumin in inhibition of cell proliferation and induction of apoptosis might occur through modulation of beta-catenin pathway in human breast cancer cells.

Research paper thumbnail of Expression analysis of maspin in invasive ductal carcinoma of breast and modulation of its expression by curcumin in breast cancer cell lines

Chemico-Biological Interactions, 2010

In breast cancer, maspin, a serine protease inhibitor, can suppress tumor growth and metastasis i... more In breast cancer, maspin, a serine protease inhibitor, can suppress tumor growth and metastasis in vivo and tumor cell motility and invasion in vitro. The clinical significance of maspin expression in breast cancer, especially in the sequence of ductal carcinoma in situ (DCIS)-invasive cancer-lymph node metastasis is well known in the Western countries, but its status in the rapidly increasing breast cancers in India remains unknown. The present study was designed to determine the clinical significance of maspin expression in invasive ductal carcinomas of breast (IDCs) in North Indian population and modulation of its expression by curcumin. Immunohistochemical analysis of maspin showed loss or reduced cytoplasmic expression in 36 of 59 (61%) tumors. Furthermore, breast cancer cells (MCF-7 (wild type p53) and MDA-MB-231 (mutant p53)) were treated with curcumin and the effect on expression of maspin gene at transcription and translation levels was analyzed by RT-PCR, immunofluorescence and Western blotting. Maspin expression was also correlated with p53 and Bcl-2 levels. Curcumin inhibited cell growth, induced apoptosis and upregulated maspin gene expression in MCF-7 cells and these findings were further correlated with the upregulation of p53 protein and downregulation of Bcl-2, suggesting maspin mediated apoptosis in MCF-7 cells. To our knowledge this is the first report showing the upregulation of maspin expression by curcumin in breast cancer cells and taken together with the clinical data suggests a potential therapeutic role for curcumin in inducing maspin mediated inhibition of invasion of breast carcinoma cells.

Research paper thumbnail of Frequent loss of Dab2 protein and infrequent promoter hypermethylation in breast cancer

Breast Cancer Research and Treatment, 2007

Disabled-2 (Dab2), a putative tumor suppressor protein, is lost in 80-90% ovarian tumors and ovar... more Disabled-2 (Dab2), a putative tumor suppressor protein, is lost in 80-90% ovarian tumors and ovarian/breast cancer cell lines. The clinical significance of Dab2 protein in breast cancer remains yet unknown. Immunohistochemical analysis of Dab2 protein showed no detectable expression in 67/91 (74%) breast tumors, while all 10 normal tissues showed presence of Dab2 protein. We hypothesized that epigenetic silencing of Dab2 may account for loss of protein in breast cancer. Methylation of Dab2 exon 1, a putative promoter, was analyzed in six breast cancer cell lines and in 54 primary breast tumors by methylation specific PCR. Methylation was observed in MDA-MB-231 and MDA-MB-157 cells and in 6 of 54 (11%) primary breast tumors that also showed loss of Dab2 protein. Expression of Dab2 transcripts was detected in all cell lines except MDA-MB-157. However, none of these six cell lines showed detectable levels of Dab2 protein by western blotting, while non-malignant mammary epithelial cell line MCF 10A showed Dab2 protein expression. To our knowledge this is the first report showing low frequency of Dab2 (putative) promoter methylation (11%) in primary breast tumors. Frequent loss of Dab2 protein (74%) suggest that hypermethylation of Dab2 promoter may only be one of the mechanisms accounting for its loss in breast cancer. Further, in silico analysis of Dab2 3'-UTR revealed existence of miRNA complimentary to this region of the gene, suggesting microRNA mediated targeting of Dab2 mRNA might account for loss of the protein in breast cancer.

Research paper thumbnail of Therapy for BRAFi-Resistant Melanomas: Is WNT5A the Answer

Research paper thumbnail of Dual mechanisms of action of the RNA-binding protein HuR explains its regulatory effect on melanoma cell migration

Translational Research, 2016

Research paper thumbnail of Potent growth suppressive activity of curcumin in human breast cancer cells: Modulation of Wnt/beta-catenin signaling

Chemico-biological interactions, Jan 7, 2009

Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta... more Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta-catenin driven downstream targets-c-Myc and cyclin D1 is associated with development of breast cancer. The objective of our study was to determine if curcumin could modulate the key elements of Wnt pathway in breast cancer cells; an effect that might underscore its usefulness for chemoprevention/treatment of this malignancy. Curcumin showed a cytotoxic effect on MCF-7 cells with 50% inhibitory concentration (IC(50)) of 35microM; while IC(50) for MDA-MB-231 cells was 30microM. Treatment with low cytostatic dose of 20microM curcumin showed G(2)/M arrest in both breast cancer cells. The effect of curcumin (20microM) treatment on expression of Wnt/beta-catenin pathway components in breast cancer cells (MCF-7 and MDA-MB-231) was analyzed by immunofluorescence and Western blotting. Curcumin was found to effectively inhibit the expression of several Wnt/beta-catenin pathway components-dishevel...

Research paper thumbnail of Bcl-2 and p53 expressions in Indian women with complete hydatidiform mole

Singapore medical journal, 2011

Hydatidiform moles have a high incidence rate in Asian countries like India. The molecular pathwa... more Hydatidiform moles have a high incidence rate in Asian countries like India. The molecular pathway leading to the pathogenesis and progression of hydatidiform moles is not yet understood. This study aimed to investigate the biological significance of Bcl-2 and p53 in complete hydatidiform moles (CHMs) as well as their influence on disease progression in the Indian population. Archival tissues from 35 patients with CHMs and 35 age-matched controls were examined for Bcl-2 and p53 expressions by immunohistochemistry. Bcl-2 was found to be immunolocalised in the cytoplasm of the syncytiotrophoblast, whereas p53 was observed in both the nucleus and cytoplasm of the syncytiotrophoblast and cytotrophoblasts. In CHMs, Bcl-2 was detected in 23 percent of patients and p53 nuclear expression, in 66 percent. A significant decrease in Bcl-2 expression was observed in CHMs (p-value is 0.015), and the down-regulation of Bcl-2 significantly correlated with higher nuclear expression of p53 (p-value ...

Research paper thumbnail of Interleukin-6 drives melanoma cell motility through p38α-MAPK-dependent up-regulation of WNT5A expression

Molecular oncology, 2014

Extensive research has demonstrated a tumor-promoting role of increased WNT5A expression in malig... more Extensive research has demonstrated a tumor-promoting role of increased WNT5A expression in malignant melanoma. However, very little light has been shed upon how WNT5A expression is up-regulated in melanoma. A potential regulator of WNT5A expression is the pro-inflammatory cytokine Interleukin (IL)-6, which shares the ability of WNT5A to increase melanoma cell invasion. Here, we investigate whether IL-6 can promote melanoma cell motility through an increased expression of WNT5A. We clearly demonstrate that the WNT5A-antagonistic peptide Box5 could inhibit IL-6-induced melanoma cell migration and invasion. Furthermore, IL-6 stimulation of the human melanoma cell lines HTB63 and A375 increased the expression of WNT5A in a dose-dependent manner. To identify the signaling mechanism responsible for this up-regulation, we explored the involvement of the three main signals induced by IL-6; STAT3, Akt and ERK 1/2. Of these, only STAT3 was activated by IL-6 in the melanoma cell lines tested....

Research paper thumbnail of Promoter hypermethylation of p16INK4A, p14ARF, CyclinD2 and Slit2 in serum and tumor DNA from breast cancer patients

Life Sciences, 2007

Epigenetic mechanisms such as DNA methylation play important role in cancer. Epigenetic alteratio... more Epigenetic mechanisms such as DNA methylation play important role in cancer. Epigenetic alterations involved in the onset and progression of breast cancer may serve as biomarkers for early detection and prediction of disease prognosis. Furthermore, using body fluids such as serum offers a non-invasive method to procure multiple samples for biomarker analyses. The aim of this study is to determine the correlation between methylation status of multiple cancer genes, p16(INK4A), p14(ARF), Cyclin D2 and Slit2 in invasive ductal carcinoma of the breast and paired serum DNA and clinicopathological parameters. Of the 36 breast cancer patients investigated, 31 (86%) tumors and 30 (83%) paired sera showed methylation of at least one of these 4 genes. Methylation frequencies varied from 27% for CyclinD2, 44% for p16(INK4A), 47% for p14(ARF) to 58% for Slit2. There was concordance between DNA methylation in tumor and paired serum DNA of each gene. This study underscores the potential utility of DNA methylation based screening of serum as a surrogate marker for tumor DNA methylation status of these genes in breast cancer. Further, expression profile of p16(INK4A) could be linked to epigenetic events, thus suggesting this pathway as a potential target for therapeutic strategies based on reversal of epigenetic silencing.

Research paper thumbnail of Wnt Signaling Pathway in Invasive Ductal Carcinoma of the Breast: Relationship between β-Catenin, Disheveled and Cyclin D1 Expression

Oncology, 2007

The Wnt/beta-catenin signaling cascade is an important signal transduction pathway in human cance... more The Wnt/beta-catenin signaling cascade is an important signal transduction pathway in human cancers. Overexpression of beta-catenin and its downstream effector, cyclin D1, is implicated in malignant transformation and acquisition of an invasive tumor phenotype. This study aimed to determine the clinical significance of Wnt/beta-catenin canonical pathway components in breast cancer. Expression of beta-catenin, dishevelled (Dvl) and cyclin D1 was examined in invasive ductal carcinomas (IDCs) of the breast by immunohistochemical analysis. Of the 98 IDCs analyzed, 30% of tumors displayed both nuclear and cytoplasmic staining of Dvl protein, while 52% showed nuclear localization. Loss of cell surface beta-catenin was observed in 66% of breast carcinomas, whereas nuclear expression was observed in 48% IDCs. Cyclin D1 overexpression was observed in 60% IDCs; 31/59 (53%) of these tumors showed nuclear expression of beta-catenin, suggesting upregulation of the canonical Wnt/beta-catenin pathway. Our study demonstrates a significant association between nuclear localization of Dvl and beta-catenin (p < 0.01, OR = 15.8). To our knowledge, this is the first study showing an association between nuclear localization of Dvl and beta-catenin in IDCs and suggests the upregulation of Wnt/beta-catenin pathway components, beta-catenin, Dvl and cyclin D1 in IDCs of the breast.

Research paper thumbnail of Clinical significance of promoter hypermethylation of RASSF1A, RARβ2, BRCA1 and HOXA5 in breast cancers of Indian patients

Research paper thumbnail of Promoter hypermethylation of TMS1, BRCA1, ERα and PRB in serum and tumor DNA of invasive ductal breast carcinoma patients

Life Sciences, 2007

Breast cancer is fast emerging as the leading cancer amongst females, especially in younger age g... more Breast cancer is fast emerging as the leading cancer amongst females, especially in younger age group in India; a large proportion of these tumors are often aggressive and ER and/or PR negative. Promoter methylation of genes involved in DNA repair and hormonal regulation may, in part, account for this behavior. To test this hypothesis methylation status of tumor suppressor genes

Research paper thumbnail of Epigenetic alterations of CDH1 and APC genes: Relationship with activation of Wnt/β-catenin Pathway in invasive ductal carcinoma of breast

Life Sciences, 2008

Activation of canonical Wnt/beta-catenin pathway in Invasive Ductal Carcinoma of Breast (IDCs) wa... more Activation of canonical Wnt/beta-catenin pathway in Invasive Ductal Carcinoma of Breast (IDCs) was recently reported from our laboratory. Herein, we analyzed promoter methylation status of CDH1 and Adenomatous polyposis coli (APC) genes in 50 IDCs and correlated with expression of E-cadherin (E-CD) and APC proteins and with activation of oncogenic Wnt/beta-catenin signaling pathway components, Dvl, beta-catenin and CyclinD1. Further, Wnt/beta-catenin driven epithelial mesenchymal transition (EMT) was investigated by correlating the expression of Dvl, beta-catenin and CyclinD1 with vimentin expression in these IDCs. Promoter hypermethylation was observed in 25/50 (50%) IDCs for CDH1 and in 11/50 (22%) tumors for APC, associated with loss of expression of E-CD and APC proteins; concordant hypermethylation of these genes was observed in paired patients' sera. Further, 57% of tumors harboring CDH1 methylation and 50% tumors harboring the methylated APC gene showed nuclear localization of beta-catenin, suggesting activation of the canonical Wnt/beta-catenin pathway. Our study demonstrates significant association between vimentin expression and nuclear beta-catenin (p=0.001; Odds ratio (OR)=25.6) and Dvl (p=0.023; OR=8.0), suggesting that EMT may be driven by Wnt/beta-catenin activation in IDCs. In conclusion, we demonstrate correlation of CDH1 and APC promoter methylation with loss of E-CD and APC proteins and with activation of Wnt/beta-catenin signaling pathway. Association of nuclear Dvl and beta-catenin with vimentin expression suggests the importance of Wnt/beta-catenin pathway driven EMT in IDCs. The concordance between CDH1 and APC methylation in IDCs and paired circulating DNA underscores the utility of serum DNA as a non-invasive tool for methylation analysis in IDC patients.

Research paper thumbnail of Potent growth suppressive activity of curcumin in human breast cancer cells: Modulation of Wnt/β-catenin signaling

Chemico-Biological Interactions, 2009

Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta... more Abnormal activation of the Wnt/beta-catenin signaling pathway and subsequent upregulation of beta-catenin driven downstream targets-c-Myc and cyclin D1 is associated with development of breast cancer. The objective of our study was to determine if curcumin could modulate the key elements of Wnt pathway in breast cancer cells; an effect that might underscore its usefulness for chemoprevention/treatment of this malignancy. Curcumin showed a cytotoxic effect on MCF-7 cells with 50% inhibitory concentration (IC(50)) of 35microM; while IC(50) for MDA-MB-231 cells was 30microM. Treatment with low cytostatic dose of 20microM curcumin showed G(2)/M arrest in both breast cancer cells. The effect of curcumin (20microM) treatment on expression of Wnt/beta-catenin pathway components in breast cancer cells (MCF-7 and MDA-MB-231) was analyzed by immunofluorescence and Western blotting. Curcumin was found to effectively inhibit the expression of several Wnt/beta-catenin pathway components-disheveled, beta-catenin, cyclin D1 and slug in both MCF-7 and MDA-MB-231. Immunofluorescence analysis showed that curcumin markedly reduced the nuclear expression of disheveled and beta-catenin proteins. Further, the protein levels of the positively regulated beta-catenin targets-cyclin D1 and slug, were downregulated by curcumin treatment. The expression levels of two integral proteins of Wnt signaling, GSK3beta and E-cadherin were also altered by curcumin treatment. In conclusion, our data demonstrated that the efficacy of curcumin in inhibition of cell proliferation and induction of apoptosis might occur through modulation of beta-catenin pathway in human breast cancer cells.

Research paper thumbnail of Expression analysis of maspin in invasive ductal carcinoma of breast and modulation of its expression by curcumin in breast cancer cell lines

Chemico-Biological Interactions, 2010

In breast cancer, maspin, a serine protease inhibitor, can suppress tumor growth and metastasis i... more In breast cancer, maspin, a serine protease inhibitor, can suppress tumor growth and metastasis in vivo and tumor cell motility and invasion in vitro. The clinical significance of maspin expression in breast cancer, especially in the sequence of ductal carcinoma in situ (DCIS)-invasive cancer-lymph node metastasis is well known in the Western countries, but its status in the rapidly increasing breast cancers in India remains unknown. The present study was designed to determine the clinical significance of maspin expression in invasive ductal carcinomas of breast (IDCs) in North Indian population and modulation of its expression by curcumin. Immunohistochemical analysis of maspin showed loss or reduced cytoplasmic expression in 36 of 59 (61%) tumors. Furthermore, breast cancer cells (MCF-7 (wild type p53) and MDA-MB-231 (mutant p53)) were treated with curcumin and the effect on expression of maspin gene at transcription and translation levels was analyzed by RT-PCR, immunofluorescence and Western blotting. Maspin expression was also correlated with p53 and Bcl-2 levels. Curcumin inhibited cell growth, induced apoptosis and upregulated maspin gene expression in MCF-7 cells and these findings were further correlated with the upregulation of p53 protein and downregulation of Bcl-2, suggesting maspin mediated apoptosis in MCF-7 cells. To our knowledge this is the first report showing the upregulation of maspin expression by curcumin in breast cancer cells and taken together with the clinical data suggests a potential therapeutic role for curcumin in inducing maspin mediated inhibition of invasion of breast carcinoma cells.

Research paper thumbnail of Frequent loss of Dab2 protein and infrequent promoter hypermethylation in breast cancer

Breast Cancer Research and Treatment, 2007

Disabled-2 (Dab2), a putative tumor suppressor protein, is lost in 80-90% ovarian tumors and ovar... more Disabled-2 (Dab2), a putative tumor suppressor protein, is lost in 80-90% ovarian tumors and ovarian/breast cancer cell lines. The clinical significance of Dab2 protein in breast cancer remains yet unknown. Immunohistochemical analysis of Dab2 protein showed no detectable expression in 67/91 (74%) breast tumors, while all 10 normal tissues showed presence of Dab2 protein. We hypothesized that epigenetic silencing of Dab2 may account for loss of protein in breast cancer. Methylation of Dab2 exon 1, a putative promoter, was analyzed in six breast cancer cell lines and in 54 primary breast tumors by methylation specific PCR. Methylation was observed in MDA-MB-231 and MDA-MB-157 cells and in 6 of 54 (11%) primary breast tumors that also showed loss of Dab2 protein. Expression of Dab2 transcripts was detected in all cell lines except MDA-MB-157. However, none of these six cell lines showed detectable levels of Dab2 protein by western blotting, while non-malignant mammary epithelial cell line MCF 10A showed Dab2 protein expression. To our knowledge this is the first report showing low frequency of Dab2 (putative) promoter methylation (11%) in primary breast tumors. Frequent loss of Dab2 protein (74%) suggest that hypermethylation of Dab2 promoter may only be one of the mechanisms accounting for its loss in breast cancer. Further, in silico analysis of Dab2 3'-UTR revealed existence of miRNA complimentary to this region of the gene, suggesting microRNA mediated targeting of Dab2 mRNA might account for loss of the protein in breast cancer.

Research paper thumbnail of Therapy for BRAFi-Resistant Melanomas: Is WNT5A the Answer