Galina Chipitsyna - Academia.edu (original) (raw)

Papers by Galina Chipitsyna

Research paper thumbnail of Thymoquinone Promotes Pancreatic Cancer Cell Death and Reduction of Tumor Size Through Combined Inhibition of Histone Deacetylation and Induction of Histone Acetylation

Journal of Surgical Research, 2012

Research paper thumbnail of Regulation of Ran GTPase By Cigarette Smoke in the Pancreas and in Pancreatic Ductal Adenocarcinoma Cells

Journal of Surgical Research, 2012

Research paper thumbnail of 812 Circadian Genes in Pancreatic Ductal Adenocarcinoma: Alterations and Clinical Correlations

Research paper thumbnail of Angiotensin II Type 2 Receptor: A Novel Modulator of Inflammation in Pancreatic Ductal Adenocarcinoma Through Regulation of NF-KappaB Activity

Journal of Surgical Research, 2012

Research paper thumbnail of c-Fos oncogene regulator Elk-1 interacts with BRCA1 splice variants BRCA1a/1b and enhances BRCA1a/1b-mediated growth suppression in breast cancer cells

Oncogene, Apr 1, 2001

Elk-1, a c-Fos protooncogene regulator, which belongs to the ETS-domain family of transcriptional... more Elk-1, a c-Fos protooncogene regulator, which belongs to the ETS-domain family of transcriptional factors, plays an important role in the induction of immediate early gene expression in response to a variety of extracellular signals. In this study, we demonstrate for the ®rst time the in vitro and in vivo interaction of Elk-1 with BRCA1 splice variants BRCA1a and BRCA1b using GST-pull down assays, co-imunoprecipitations/Western blot analysis of cell extracts from breast cancer cells and mammalian two-hybrid assays. We have localized the BRCA1 interaction domain of Elk-1 protein to the conserved ETS domain, a motif involved in DNA binding and protein ± protein interactions. We also observed binding of BRCA1 proteins to other ETS-domain transcription factors SAP1, ETS-1, ERG-2 and Fli-1 but not to Elk-1 splice variant DElk-1 and c-Fos protooncogene. Both BRCA1a and BRCA1b splice variants function as growth suppressors of human breast cancer cells. Interestingly, our studies reveal that although both Elk-1 and SAP-1 are highly homologous members of a subfamily of ETS domain proteins called ternary complex factors, it is only Elk-1 but not SAP-1 that can augment the growth suppressive function of BRCA1a/1b proteins in breast cancer cells. Thus Elk-1 could be a potential downstream target of BRCA1 in its growth control pathway. Furthermore, we have observed inhibition of c-Fos promoter activity in BRCA1a transfected stable breast cancer cells and over expression of BRCA1a/1b attenuates MEK-induced SRE activation in vivo. These results demonstrate for the ®rst time a link between the growth suppressive function of BRCA1a/1b proteins and signal transduction pathway involving Elk-1 protein. All these results taken together suggest that one of the mechanisms by which BRCA1a/1b proteins function as growth/tumor suppressors is through inhibition of the expression of Elk-1 target genes like c-Fos.

Research paper thumbnail of Conserved Metabolic Changes in Nondiabetic and Type 2 Diabetic Bariatric Surgery Patients: Global Metabolomic Pilot Study

Journal of Diabetes Research, 2016

The goal of this study was to provide insight into the mechanism by which bariatric surgical proc... more The goal of this study was to provide insight into the mechanism by which bariatric surgical procedures led to weight loss and improvement or resolution of diabetes. Global biochemical profiling was used to evaluate changes occurring in nondiabetic and type 2 diabetic (T2D) patients experiencing either less extreme sleeve gastrectomy or a full gastric bypass. We were able to identify changes in metabolism that were affected by standard preoperation liquid weight loss diet as well as by bariatric surgery itself. Preoperation weight-loss diet was associated with a strong lipid metabolism signature largely related to the consumption of adipose reserves for energy production. Glucose usage shift away from glycolytic pyruvate production toward pentose phosphate pathway, via glucose-6-phosphate, appeared to be shared across all patients regardless of T2D status or bariatric surgery procedure. Our results suggested that bariatric surgery might promote antioxidant defense and insulin sensitivity through both increased heme synthesis and HO activity or expression. Changes in histidine and its metabolites following surgery might be an indication of altered gut microbiome ecology or liver function. This initial study provided broad understanding of how metabolism changed globally in morbidly obese nondiabetic and T2D patients following weight-loss surgery.

Research paper thumbnail of RAN GTPase and Osteopontin in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis among cancers, mainly due to the h... more Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis among cancers, mainly due to the high incidence of early metastases. RAN small GTPase (RAN) is a protein that plays physiological roles in the regulation of nuclear transport and microtubule spindle assembly. RAN was recently shown to mediate the invasive functions of the prometastatic protein osteopontin (OPN) in breast cancer cells. We and others have shown previously that high levels of OPN are present in PDA. In this study, we analyzed the expression and correlation of RAN with OPN in human pancreatic lesions, and explored their regulation in PDA cell lines. Real time PCR was used to analyze RAN and OPN mRNA levels in PDA, adjacent non-malignant, and benign pancreatic tissues. Expression levels were correlated with survival and different clinicopathological parameters using different statistical methods. Transient transfection studies using OPN and RAN plasmids, and knockdown experiments using siRNA were used to examine their mutual regulation. OPN and RAN levels highly correlated with each other (p<0.0001). OPN or RAN levels did not correlate with venous lymphatic invasion, diabetes, obesity, T stage, BMI, or survival. However, we found a significant association between RAN levels and perineural invasion (HR=0.79, 95% CI 0.59, 1.07; p=0.0378.). OPN and RAN colocalized in PDA tissues and cell lines. Increasing RAN expression in PDA cells induced OPN transcription and RAN silencing reduced total OPN levels. OPN did not have any significant effect on RAN transcription. The high levels of RAN in PDA and its correlation with OPN and with perineural invasion suggest that RAN may contribute to PDA metastasis and progression through the induction of OPN. RAN's role in the regulation of OPN in PDA is unique and could provide potential novel therapeutic strategies to combat PDA aggressiveness.

Research paper thumbnail of Expression and regulation of nicotine receptor and osteopontin isoforms in human pancreatic ductal adenocarcinoma

Histology and Histopathology Cellular and Molecular Biology, Jul 1, 2011

Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotyp... more Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotype. We have recently shown that nicotine, a risk factor in pancreatic ductal adenocarcinoma (PDA), induces an alpha7-nicotine acetylcholine receptor (α7-nAChR)-mediated increase of OPN in PDA cells. In this study, we tested nicotine's effect on the expression of OPN splice variants (OPNa, b, c) in PDA cells. We also analyzed the correlation between patients' smoking history with OPN and α7-nAChR levels. RT-PCR and UV-light-illumination of ethidium-bromide staining were used to examine the mRNA expression in tissue and PDA cells treated with or without nicotine (3-300 nM). Localization of total OPN, OPNc and α7-nAChR was analyzed by immunohistochemistry, and their mRNA tissue expression levels were correlated with the patients' smoking history. PDA cells expressed varying levels of OPNa, OPNb, and α7-nAChR. Nicotine treatment selectively induced denovo expression of OPNc and increased α7-nAChR expression levels. In PDA tissue, OPNc was found in 87% of lesions, of which 73% were smokers. OPNc and total OPN levels were correlated in the tissue from patients with invasive PDA. Nicotine receptor was expressed in the invasive and premalignant lesions without clear correlation with smoking history. We show here for the first time that α7-nAChR is expressed in PDA cells and tissues and is regulated by nicotine in PDA cells. This, together with our previous findings that α7-nAChR mediates the metastatic effects of nicotine in PDA, suggest that combined targeting of α7-nAChR and OPNc could be a valid novel therapeutic strategy for invasive PDA, especially in the smoking population.

Research paper thumbnail of Expression and regulation of osteopontin in type 1 diabetes

Http Dx Doi Org 10 4161 Isl 1 1 8629, Jul 1, 2009

Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and i... more Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and immune-modulating disorders. We previously demonstrated that OPN is a novel islet protein and a pro survival factor that may serve as an intrinsic feedback regulator of nitric oxide signaling in β-cells. Here, we investigated the endogenous expression of pancreatic OPN in non obese diabetic (NOD) mice and explored its regulation in the islets and b-cells. High levels of pancreatic OPN mRNA and protein were seen in the prediabetic NOD mice pancreata. The temporal pattern of OPN expression inversely correlated with progression of insulitis and β-cell destruction. Immunostaining of pancreatic serial sections showed co localization of OPN with most of the islet hormones. Next we investigated the regulation of OPN in the islets and β-cells. Naturally occurring early upregulation of OPN transcription was seen after exposure of native normoglycemic NOD islets and β-cells to a high-dose combination of IL-1β, TNF-α and IFN-γ. To distinguish between the effect of cytokines and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with cytokines or glucose. Cytokines induced upregulation of OPN promoter activity within one hour, while glucose induced a dose-dependent upregulation of OPN promoter activity after 24 hrs. Long-term exposures to cytokines or glucose reduced OPN expression and promoter activity. Our data provide the first observations into the presence of a positive intrinsic mechanism that regulates pancreatic OPN expression. Based upon previous studies that support a protective role of OPN in the islets, our data suggest that exhaustion of this local OPN system is implicated in the associated loss of endogenous islet protection and progression of the destructive insulitis and diabetes severity in the NOD mouse model.

Research paper thumbnail of 918 Overexpressing TNF-Alpha in Pancreatic Ductal Adenocarcinoma Cells and Fibroblasts Modifies Cell Survival and Reduces Fatty Acid Synthesis via Downregulation of Sterol Regulatory Element Binding Protein-1 and Activation of Acetyl CoA Carboxylase

Research paper thumbnail of Osteopontin Splice Variant as a Potential Marker for Metastatic Disease in Pancreatic Cancer

Research paper thumbnail of 199 Clinical Significance of Serum Col6a3 Isoforms in Pancreatic Ductal Adenocarcinoma

Research paper thumbnail of Involvement of osteopontin in the matrix-degrading and proangiogenic changes mediated by nicotine in pancreatic cancer cells

Journal of Gastrointestinal Surgery

Substantial evidence indicates that exposure to cigarette smoke is associated with an elevated ri... more Substantial evidence indicates that exposure to cigarette smoke is associated with an elevated risk of pancreatic ductal adenocarcinoma (PDA). However, the mechanisms underlying the effects of nicotine on the development or progression of PDA remain to be investigated. Previously, we showed that nicotine promotes the expression of osteopontin c (OPNc), an isoform of OPN protein that confers on cancer cells a migratory phenotype. In this study, we explored the potential prometastatic role of nicotine in PDA through studying its effect on the expression of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) and evaluated the role of OPN in mediating these effects. MMP-9 and VEGF mRNA and protein were analyzed in PDA cells treated with or without nicotine (3-300 nM). Transient transfection and luciferase-labeled promoter studies evaluated the effects of OPNc and OPN protein on the transcription and translation of MMP-9 and VEGF. Real-time PCR and immunohist...

Research paper thumbnail of Mo1839 Osteopontin (Opn) Isoforms, Diabetes, Obesity, and Cancer; What's One Got to Do With the Other? A New Role for Opn

Research paper thumbnail of Sa1997 Osteopontin Splice Variant As a Potential Prognostic Marker for Pancreatic Adenocarcinoma

Research paper thumbnail of Antihypertensives as novel antineoplastics: angiotensin-I-converting enzyme inhibitors and angiotensin II type 1 receptor blockers in pancreatic ductal adenocarcinoma

Journal of the American College of Surgeons, 2007

Vascular endothelial growth factor (VEGF) is a crucial proangiogenic component in pancreatic duct... more Vascular endothelial growth factor (VEGF) is a crucial proangiogenic component in pancreatic ductal adenocarcinoma (PDA), and its high expression levels have been correlated with poor prognosis and early postoperative recurrence. Angiotensin II (AngII), which has been shown to increase VEGF production in a variety of cancers, is actively generated in the pancreas. We hypothesized that AngII plays a crucial role in PDA-associated angiogenesis. We analyzed the expression and localization of AngI converting enzyme (ACE) and AngII type 1 receptor (AT1R) in relation to VEGF in matched invasive human PDA (n=25) and surrounding nonmalignant tissues using real-time polymerase chain reaction, Western immunoblotting, and immunohistochemistry. VEGF levels in conditioned media of HS766T and PK9 PDA cells treated with or without AngII (10(-7) mol/L) were measured by ELISA. The effects of an AT1R blocker (losartan) and an ACE inhibitor (captopril) on VEGF production and cellular proliferation wer...

Research paper thumbnail of Induction of monocyte chemoattractant protein-1 expression by angiotensin II in the pancreatic islets and beta-cells

Endocrinology, 2007

Angiotensin II (AngII), the principal hormone of the renin-angiotensin system, is actively genera... more Angiotensin II (AngII), the principal hormone of the renin-angiotensin system, is actively generated in the pancreas and has been suggested as a key mediator of inflammation. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays an important role in the recruitment of mononuclear cells into the pancreatic islets. In this study, we investigated the potential molecular basis for the role of AngII in islet inflammation through studying its effect on MCP-1. AngII significantly increased the expression of MCP-1 mRNA and protein in the RINm5F beta-cell line and activated MCP-1 promoter. AngII-MCP-1 mRNA induction was inhibited by an AngII type 1 receptor antagonist but was unchanged by an AngII type 2 receptor antagonist. AngII-MCP-1 induction was inhibited by the tyrosine kinase inhibitor genistein, suggesting a MAPK signaling mechanism. AngII activated the phosphorylation of ERK1/2 but not p38 or c-Jun NH(2)-terminal MAPKs. Inhibition of ERK1/2 activation reduced the AngI...

Research paper thumbnail of Expression and regulation of osteopontin in type 1 diabetes

Islets, 2009

Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and i... more Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and immune-modulating disorders. We previously demonstrated that OPN is a novel islet protein and a pro survival factor that may serve as an intrinsic feedback regulator of nitric oxide signaling in β-cells. Here, we investigated the endogenous expression of pancreatic OPN in non obese diabetic (NOD) mice and explored its regulation in the islets and b-cells. High levels of pancreatic OPN mRNA and protein were seen in the prediabetic NOD mice pancreata. The temporal pattern of OPN expression inversely correlated with progression of insulitis and β-cell destruction. Immunostaining of pancreatic serial sections showed co localization of OPN with most of the islet hormones. Next we investigated the regulation of OPN in the islets and β-cells. Naturally occurring early upregulation of OPN transcription was seen after exposure of native normoglycemic NOD islets and β-cells to a high-dose combination of IL-1β, TNF-α and IFN-γ. To distinguish between the effect of cytokines and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with cytokines or glucose. Cytokines induced upregulation of OPN promoter activity within one hour, while glucose induced a dose-dependent upregulation of OPN promoter activity after 24 hrs. Long-term exposures to cytokines or glucose reduced OPN expression and promoter activity. Our data provide the first observations into the presence of a positive intrinsic mechanism that regulates pancreatic OPN expression. Based upon previous studies that support a protective role of OPN in the islets, our data suggest that exhaustion of this local OPN system is implicated in the associated loss of endogenous islet protection and progression of the destructive insulitis and diabetes severity in the NOD mouse model.

Research paper thumbnail of 589 Involvement of Osteopontin in the Matrix Degrading and Proangiogenic Changes Mediated by Nicotine in Pancreatic Cancer Cells

Bile duct cysts are an uncommon condition that may cause significant morbidity and are considered... more Bile duct cysts are an uncommon condition that may cause significant morbidity and are considered a risk factor for hepatobiliary malignancy. Standard treatment is resection and has traditionally been performed using an "open" laparotomy incision. Laparoscopic resection and reconstruction is feasible and safe as reported in the existing literature in small series. A minimally invasive approach requires experience in both hepatobiliary surgery and advanced laparoscopic skills. This video presents a 43 year-old female who presented with a symptomatic Type IV bile duct cyst and demonstrates the key technical aspects of extrahepatic bile duct resection with Roux-en-Y reconstruction.

Research paper thumbnail of Expression and regulation of nicotine receptor and osteopontin isoforms in human pancreatic ductal adenocarcinoma

Histology and histopathology, 2011

Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotyp... more Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotype. We have recently shown that nicotine, a risk factor in pancreatic ductal adenocarcinoma (PDA), induces an alpha7-nicotine acetylcholine receptor (α7-nAChR)-mediated increase of OPN in PDA cells. In this study, we tested nicotine's effect on the expression of OPN splice variants (OPNa, b, c) in PDA cells. We also analyzed the correlation between patients' smoking history with OPN and α7-nAChR levels. RT-PCR and UV-light-illumination of ethidium-bromide staining were used to examine the mRNA expression in tissue and PDA cells treated with or without nicotine (3-300 nM). Localization of total OPN, OPNc and α7-nAChR was analyzed by immunohistochemistry, and their mRNA tissue expression levels were correlated with the patients' smoking history. PDA cells expressed varying levels of OPNa, OPNb, and α7-nAChR. Nicotine treatment selectively induced denovo expression of OPNc and in...

Research paper thumbnail of Thymoquinone Promotes Pancreatic Cancer Cell Death and Reduction of Tumor Size Through Combined Inhibition of Histone Deacetylation and Induction of Histone Acetylation

Journal of Surgical Research, 2012

Research paper thumbnail of Regulation of Ran GTPase By Cigarette Smoke in the Pancreas and in Pancreatic Ductal Adenocarcinoma Cells

Journal of Surgical Research, 2012

Research paper thumbnail of 812 Circadian Genes in Pancreatic Ductal Adenocarcinoma: Alterations and Clinical Correlations

Research paper thumbnail of Angiotensin II Type 2 Receptor: A Novel Modulator of Inflammation in Pancreatic Ductal Adenocarcinoma Through Regulation of NF-KappaB Activity

Journal of Surgical Research, 2012

Research paper thumbnail of c-Fos oncogene regulator Elk-1 interacts with BRCA1 splice variants BRCA1a/1b and enhances BRCA1a/1b-mediated growth suppression in breast cancer cells

Oncogene, Apr 1, 2001

Elk-1, a c-Fos protooncogene regulator, which belongs to the ETS-domain family of transcriptional... more Elk-1, a c-Fos protooncogene regulator, which belongs to the ETS-domain family of transcriptional factors, plays an important role in the induction of immediate early gene expression in response to a variety of extracellular signals. In this study, we demonstrate for the ®rst time the in vitro and in vivo interaction of Elk-1 with BRCA1 splice variants BRCA1a and BRCA1b using GST-pull down assays, co-imunoprecipitations/Western blot analysis of cell extracts from breast cancer cells and mammalian two-hybrid assays. We have localized the BRCA1 interaction domain of Elk-1 protein to the conserved ETS domain, a motif involved in DNA binding and protein ± protein interactions. We also observed binding of BRCA1 proteins to other ETS-domain transcription factors SAP1, ETS-1, ERG-2 and Fli-1 but not to Elk-1 splice variant DElk-1 and c-Fos protooncogene. Both BRCA1a and BRCA1b splice variants function as growth suppressors of human breast cancer cells. Interestingly, our studies reveal that although both Elk-1 and SAP-1 are highly homologous members of a subfamily of ETS domain proteins called ternary complex factors, it is only Elk-1 but not SAP-1 that can augment the growth suppressive function of BRCA1a/1b proteins in breast cancer cells. Thus Elk-1 could be a potential downstream target of BRCA1 in its growth control pathway. Furthermore, we have observed inhibition of c-Fos promoter activity in BRCA1a transfected stable breast cancer cells and over expression of BRCA1a/1b attenuates MEK-induced SRE activation in vivo. These results demonstrate for the ®rst time a link between the growth suppressive function of BRCA1a/1b proteins and signal transduction pathway involving Elk-1 protein. All these results taken together suggest that one of the mechanisms by which BRCA1a/1b proteins function as growth/tumor suppressors is through inhibition of the expression of Elk-1 target genes like c-Fos.

Research paper thumbnail of Conserved Metabolic Changes in Nondiabetic and Type 2 Diabetic Bariatric Surgery Patients: Global Metabolomic Pilot Study

Journal of Diabetes Research, 2016

The goal of this study was to provide insight into the mechanism by which bariatric surgical proc... more The goal of this study was to provide insight into the mechanism by which bariatric surgical procedures led to weight loss and improvement or resolution of diabetes. Global biochemical profiling was used to evaluate changes occurring in nondiabetic and type 2 diabetic (T2D) patients experiencing either less extreme sleeve gastrectomy or a full gastric bypass. We were able to identify changes in metabolism that were affected by standard preoperation liquid weight loss diet as well as by bariatric surgery itself. Preoperation weight-loss diet was associated with a strong lipid metabolism signature largely related to the consumption of adipose reserves for energy production. Glucose usage shift away from glycolytic pyruvate production toward pentose phosphate pathway, via glucose-6-phosphate, appeared to be shared across all patients regardless of T2D status or bariatric surgery procedure. Our results suggested that bariatric surgery might promote antioxidant defense and insulin sensitivity through both increased heme synthesis and HO activity or expression. Changes in histidine and its metabolites following surgery might be an indication of altered gut microbiome ecology or liver function. This initial study provided broad understanding of how metabolism changed globally in morbidly obese nondiabetic and T2D patients following weight-loss surgery.

Research paper thumbnail of RAN GTPase and Osteopontin in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis among cancers, mainly due to the h... more Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis among cancers, mainly due to the high incidence of early metastases. RAN small GTPase (RAN) is a protein that plays physiological roles in the regulation of nuclear transport and microtubule spindle assembly. RAN was recently shown to mediate the invasive functions of the prometastatic protein osteopontin (OPN) in breast cancer cells. We and others have shown previously that high levels of OPN are present in PDA. In this study, we analyzed the expression and correlation of RAN with OPN in human pancreatic lesions, and explored their regulation in PDA cell lines. Real time PCR was used to analyze RAN and OPN mRNA levels in PDA, adjacent non-malignant, and benign pancreatic tissues. Expression levels were correlated with survival and different clinicopathological parameters using different statistical methods. Transient transfection studies using OPN and RAN plasmids, and knockdown experiments using siRNA were used to examine their mutual regulation. OPN and RAN levels highly correlated with each other (p<0.0001). OPN or RAN levels did not correlate with venous lymphatic invasion, diabetes, obesity, T stage, BMI, or survival. However, we found a significant association between RAN levels and perineural invasion (HR=0.79, 95% CI 0.59, 1.07; p=0.0378.). OPN and RAN colocalized in PDA tissues and cell lines. Increasing RAN expression in PDA cells induced OPN transcription and RAN silencing reduced total OPN levels. OPN did not have any significant effect on RAN transcription. The high levels of RAN in PDA and its correlation with OPN and with perineural invasion suggest that RAN may contribute to PDA metastasis and progression through the induction of OPN. RAN's role in the regulation of OPN in PDA is unique and could provide potential novel therapeutic strategies to combat PDA aggressiveness.

Research paper thumbnail of Expression and regulation of nicotine receptor and osteopontin isoforms in human pancreatic ductal adenocarcinoma

Histology and Histopathology Cellular and Molecular Biology, Jul 1, 2011

Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotyp... more Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotype. We have recently shown that nicotine, a risk factor in pancreatic ductal adenocarcinoma (PDA), induces an alpha7-nicotine acetylcholine receptor (α7-nAChR)-mediated increase of OPN in PDA cells. In this study, we tested nicotine's effect on the expression of OPN splice variants (OPNa, b, c) in PDA cells. We also analyzed the correlation between patients' smoking history with OPN and α7-nAChR levels. RT-PCR and UV-light-illumination of ethidium-bromide staining were used to examine the mRNA expression in tissue and PDA cells treated with or without nicotine (3-300 nM). Localization of total OPN, OPNc and α7-nAChR was analyzed by immunohistochemistry, and their mRNA tissue expression levels were correlated with the patients' smoking history. PDA cells expressed varying levels of OPNa, OPNb, and α7-nAChR. Nicotine treatment selectively induced denovo expression of OPNc and increased α7-nAChR expression levels. In PDA tissue, OPNc was found in 87% of lesions, of which 73% were smokers. OPNc and total OPN levels were correlated in the tissue from patients with invasive PDA. Nicotine receptor was expressed in the invasive and premalignant lesions without clear correlation with smoking history. We show here for the first time that α7-nAChR is expressed in PDA cells and tissues and is regulated by nicotine in PDA cells. This, together with our previous findings that α7-nAChR mediates the metastatic effects of nicotine in PDA, suggest that combined targeting of α7-nAChR and OPNc could be a valid novel therapeutic strategy for invasive PDA, especially in the smoking population.

Research paper thumbnail of Expression and regulation of osteopontin in type 1 diabetes

Http Dx Doi Org 10 4161 Isl 1 1 8629, Jul 1, 2009

Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and i... more Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and immune-modulating disorders. We previously demonstrated that OPN is a novel islet protein and a pro survival factor that may serve as an intrinsic feedback regulator of nitric oxide signaling in β-cells. Here, we investigated the endogenous expression of pancreatic OPN in non obese diabetic (NOD) mice and explored its regulation in the islets and b-cells. High levels of pancreatic OPN mRNA and protein were seen in the prediabetic NOD mice pancreata. The temporal pattern of OPN expression inversely correlated with progression of insulitis and β-cell destruction. Immunostaining of pancreatic serial sections showed co localization of OPN with most of the islet hormones. Next we investigated the regulation of OPN in the islets and β-cells. Naturally occurring early upregulation of OPN transcription was seen after exposure of native normoglycemic NOD islets and β-cells to a high-dose combination of IL-1β, TNF-α and IFN-γ. To distinguish between the effect of cytokines and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with cytokines or glucose. Cytokines induced upregulation of OPN promoter activity within one hour, while glucose induced a dose-dependent upregulation of OPN promoter activity after 24 hrs. Long-term exposures to cytokines or glucose reduced OPN expression and promoter activity. Our data provide the first observations into the presence of a positive intrinsic mechanism that regulates pancreatic OPN expression. Based upon previous studies that support a protective role of OPN in the islets, our data suggest that exhaustion of this local OPN system is implicated in the associated loss of endogenous islet protection and progression of the destructive insulitis and diabetes severity in the NOD mouse model.

Research paper thumbnail of 918 Overexpressing TNF-Alpha in Pancreatic Ductal Adenocarcinoma Cells and Fibroblasts Modifies Cell Survival and Reduces Fatty Acid Synthesis via Downregulation of Sterol Regulatory Element Binding Protein-1 and Activation of Acetyl CoA Carboxylase

Research paper thumbnail of Osteopontin Splice Variant as a Potential Marker for Metastatic Disease in Pancreatic Cancer

Research paper thumbnail of 199 Clinical Significance of Serum Col6a3 Isoforms in Pancreatic Ductal Adenocarcinoma

Research paper thumbnail of Involvement of osteopontin in the matrix-degrading and proangiogenic changes mediated by nicotine in pancreatic cancer cells

Journal of Gastrointestinal Surgery

Substantial evidence indicates that exposure to cigarette smoke is associated with an elevated ri... more Substantial evidence indicates that exposure to cigarette smoke is associated with an elevated risk of pancreatic ductal adenocarcinoma (PDA). However, the mechanisms underlying the effects of nicotine on the development or progression of PDA remain to be investigated. Previously, we showed that nicotine promotes the expression of osteopontin c (OPNc), an isoform of OPN protein that confers on cancer cells a migratory phenotype. In this study, we explored the potential prometastatic role of nicotine in PDA through studying its effect on the expression of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) and evaluated the role of OPN in mediating these effects. MMP-9 and VEGF mRNA and protein were analyzed in PDA cells treated with or without nicotine (3-300 nM). Transient transfection and luciferase-labeled promoter studies evaluated the effects of OPNc and OPN protein on the transcription and translation of MMP-9 and VEGF. Real-time PCR and immunohist...

Research paper thumbnail of Mo1839 Osteopontin (Opn) Isoforms, Diabetes, Obesity, and Cancer; What's One Got to Do With the Other? A New Role for Opn

Research paper thumbnail of Sa1997 Osteopontin Splice Variant As a Potential Prognostic Marker for Pancreatic Adenocarcinoma

Research paper thumbnail of Antihypertensives as novel antineoplastics: angiotensin-I-converting enzyme inhibitors and angiotensin II type 1 receptor blockers in pancreatic ductal adenocarcinoma

Journal of the American College of Surgeons, 2007

Vascular endothelial growth factor (VEGF) is a crucial proangiogenic component in pancreatic duct... more Vascular endothelial growth factor (VEGF) is a crucial proangiogenic component in pancreatic ductal adenocarcinoma (PDA), and its high expression levels have been correlated with poor prognosis and early postoperative recurrence. Angiotensin II (AngII), which has been shown to increase VEGF production in a variety of cancers, is actively generated in the pancreas. We hypothesized that AngII plays a crucial role in PDA-associated angiogenesis. We analyzed the expression and localization of AngI converting enzyme (ACE) and AngII type 1 receptor (AT1R) in relation to VEGF in matched invasive human PDA (n=25) and surrounding nonmalignant tissues using real-time polymerase chain reaction, Western immunoblotting, and immunohistochemistry. VEGF levels in conditioned media of HS766T and PK9 PDA cells treated with or without AngII (10(-7) mol/L) were measured by ELISA. The effects of an AT1R blocker (losartan) and an ACE inhibitor (captopril) on VEGF production and cellular proliferation wer...

Research paper thumbnail of Induction of monocyte chemoattractant protein-1 expression by angiotensin II in the pancreatic islets and beta-cells

Endocrinology, 2007

Angiotensin II (AngII), the principal hormone of the renin-angiotensin system, is actively genera... more Angiotensin II (AngII), the principal hormone of the renin-angiotensin system, is actively generated in the pancreas and has been suggested as a key mediator of inflammation. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays an important role in the recruitment of mononuclear cells into the pancreatic islets. In this study, we investigated the potential molecular basis for the role of AngII in islet inflammation through studying its effect on MCP-1. AngII significantly increased the expression of MCP-1 mRNA and protein in the RINm5F beta-cell line and activated MCP-1 promoter. AngII-MCP-1 mRNA induction was inhibited by an AngII type 1 receptor antagonist but was unchanged by an AngII type 2 receptor antagonist. AngII-MCP-1 induction was inhibited by the tyrosine kinase inhibitor genistein, suggesting a MAPK signaling mechanism. AngII activated the phosphorylation of ERK1/2 but not p38 or c-Jun NH(2)-terminal MAPKs. Inhibition of ERK1/2 activation reduced the AngI...

Research paper thumbnail of Expression and regulation of osteopontin in type 1 diabetes

Islets, 2009

Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and i... more Osteopontin (OPN) is a secreted acidic phosphoprotein that is involved in many inflammatory and immune-modulating disorders. We previously demonstrated that OPN is a novel islet protein and a pro survival factor that may serve as an intrinsic feedback regulator of nitric oxide signaling in β-cells. Here, we investigated the endogenous expression of pancreatic OPN in non obese diabetic (NOD) mice and explored its regulation in the islets and b-cells. High levels of pancreatic OPN mRNA and protein were seen in the prediabetic NOD mice pancreata. The temporal pattern of OPN expression inversely correlated with progression of insulitis and β-cell destruction. Immunostaining of pancreatic serial sections showed co localization of OPN with most of the islet hormones. Next we investigated the regulation of OPN in the islets and β-cells. Naturally occurring early upregulation of OPN transcription was seen after exposure of native normoglycemic NOD islets and β-cells to a high-dose combination of IL-1β, TNF-α and IFN-γ. To distinguish between the effect of cytokines and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with cytokines or glucose. Cytokines induced upregulation of OPN promoter activity within one hour, while glucose induced a dose-dependent upregulation of OPN promoter activity after 24 hrs. Long-term exposures to cytokines or glucose reduced OPN expression and promoter activity. Our data provide the first observations into the presence of a positive intrinsic mechanism that regulates pancreatic OPN expression. Based upon previous studies that support a protective role of OPN in the islets, our data suggest that exhaustion of this local OPN system is implicated in the associated loss of endogenous islet protection and progression of the destructive insulitis and diabetes severity in the NOD mouse model.

Research paper thumbnail of 589 Involvement of Osteopontin in the Matrix Degrading and Proangiogenic Changes Mediated by Nicotine in Pancreatic Cancer Cells

Bile duct cysts are an uncommon condition that may cause significant morbidity and are considered... more Bile duct cysts are an uncommon condition that may cause significant morbidity and are considered a risk factor for hepatobiliary malignancy. Standard treatment is resection and has traditionally been performed using an "open" laparotomy incision. Laparoscopic resection and reconstruction is feasible and safe as reported in the existing literature in small series. A minimally invasive approach requires experience in both hepatobiliary surgery and advanced laparoscopic skills. This video presents a 43 year-old female who presented with a symptomatic Type IV bile duct cyst and demonstrates the key technical aspects of extrahepatic bile duct resection with Roux-en-Y reconstruction.

Research paper thumbnail of Expression and regulation of nicotine receptor and osteopontin isoforms in human pancreatic ductal adenocarcinoma

Histology and histopathology, 2011

Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotyp... more Osteopontin (OPN) is a secreted phospho-protein that confers on cancer cells a migratory phenotype. We have recently shown that nicotine, a risk factor in pancreatic ductal adenocarcinoma (PDA), induces an alpha7-nicotine acetylcholine receptor (α7-nAChR)-mediated increase of OPN in PDA cells. In this study, we tested nicotine's effect on the expression of OPN splice variants (OPNa, b, c) in PDA cells. We also analyzed the correlation between patients' smoking history with OPN and α7-nAChR levels. RT-PCR and UV-light-illumination of ethidium-bromide staining were used to examine the mRNA expression in tissue and PDA cells treated with or without nicotine (3-300 nM). Localization of total OPN, OPNc and α7-nAChR was analyzed by immunohistochemistry, and their mRNA tissue expression levels were correlated with the patients' smoking history. PDA cells expressed varying levels of OPNa, OPNb, and α7-nAChR. Nicotine treatment selectively induced denovo expression of OPNc and in...