Proceedings of the National Academy of Sciences, 2001
O 6 -methylguanine ( O 6 mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have... more O 6 -methylguanine ( O 6 mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have evolved with a DNA repair mechanism that largely ameliorates the deleterious effects of O 6 mG through a direct reversal mechanism by a protein termed O 6 -methylguanine-DNA methyltransferase (MGMT). However, the contribution of O 6 mG to carcinogenesis, in the absence of known exposure to agents that produce it, has not been defined. Nontransgenic C3HeB male mice have a high frequency of spontaneous liver tumors. Transgenic CeHeB/FeJ mice expressing human MGMT (hMGMT) were generated that had elevated hepatic MGMT activity. The spontaneous development of hepatocellular carcinoma was significantly reduced in those mice expressing hMGMT compared with nontransgenic C3HeB/FeJ male mice. No differences were detected in spontaneous mutant frequencies in lacI transgenes in mice carrying hMGMT compared with that without hMGMT but the proportion of GC to AT transition mutations was lower in the ...
There is growing evidence that chemokines and their receptors regulate the movement and in- terac... more There is growing evidence that chemokines and their receptors regulate the movement and in- teraction of antigen-presenting cells such as dendritic cells (DCs) and T cells. We tested the hy- pothesis that the CC chemokine receptor (CCR)2 and CCR5 and the chemokine macrophage inflammatory protein (MIP)-1 a , a ligand for CCR5, influence DC migration and localization. We found that deficiency of CCR2 but not CCR5 or MIP-1 a led to distinct defects in DC bi- ology. Langerhans cell (skin DC) density in CCR2-null mice was normal, and their ability to migrate into the dermis was intact; however, their migration to the draining lymph nodes was markedly impaired. CCR2-null mice had lower numbers of DCs in the spleen, and this was primarily due to a reduction in the CD8 a 1 T helper cell type 1 (Th1)-inducing subset of DCs. Additionally, there was a block in the Leishmania major infection-induced relocalization of splenic DCs from the marginal zone to the T cell areas. We propose that these ...
There is growing evidence that chemokines and their receptors regulate the movement and interacti... more There is growing evidence that chemokines and their receptors regulate the movement and interaction of antigen-presenting cells such as dendritic cells (DCs) and T cells. We tested the hypothesis that the CC chemokine receptor (CCR)2 and CCR5 and the chemokine macrophage inflammatory protein (MIP)-1α, a ligand for CCR5, influence DC migration and localization. We found that deficiency of CCR2 but not CCR5 or MIP-1α led to distinct defects in DC biology. Langerhans cell (skin DC) density in CCR2-null mice was normal, and their ability to migrate into the dermis was intact; however, their migration to the draining lymph nodes was markedly impaired. CCR2-null mice had lower numbers of DCs in the spleen, and this was primarily due to a reduction in the CD8α1 T helper cell type 1 (Th1)-inducing subset of DCs. Additionally, there was a block in the Leishmania major infection–induced relocalization of splenic DCs from the marginal zone to the T cell areas. We propose that these DC defects,...
We observed the repair process of the choriocapillaris after confluent argon laser retinal photoc... more We observed the repair process of the choriocapillaris after confluent argon laser retinal photocoagulation in the domestic cat with a plastic injection-corrosion technique coupled with scanning electron microscopy and transmission electron microscopy. Confluent photocoagulation was applied to the area of the retinal tapetum, creating two kinds of lesions: one consisted of five confluent burns and the other of 20 confluent burns. Specimens were prepared at 1, 30, and 60 days. Occlusion of the choriocapillaris was noted regardless of the length of time after photocoagulation. The only sign of repair was noted at 60 days when the choriocapillaris located at the edge of the lesion showed a uniform rearrangement. Transmission electron microscopy revealed severe damage to the endothelial cells, with lack of cell activation and permanent capillary closure in the vessels of the lesion proper.
Cancer prevention research (Philadelphia, Pa.), Jan 14, 2015
Hepatocellular carcinoma (HCC) is increasingly important in the United States as the incidence ra... more Hepatocellular carcinoma (HCC) is increasingly important in the United States as the incidence rate rose over the last 30 years. C3HeB/FeJ mice serve as a unique model to study HCC tumorigenesis because they mimic human HCC with delayed onset, male gender bias, a ~50% incidence, and susceptibility to tumorigenesis is mediated through multiple genetic loci. Because a human O6-methylguanine-DNA methyltransferase (hMGMT) transgene reduces spontaneous tumorigenesis in this model, we hypothesized that hMGMT would also protect from methylation-induced hepatocarcinogenesis. To test this hypothesis, wild type and hMGMT transgenic C3HeB/FeJ male mice were treated with two monofunctional alkylating agents: diethylnitrosamine (DEN) (0.025 µmol/g body weight) on day 12 of life with evaluation for glucose-6-phosphatase deficient (G6PD) foci at 16, 24, and 32 weeks or N-methyl-N-nitrosurea (MNU) (25 mg MNU/kg body weight) once monthly for 7 months starting at 3 months of age with evaluation for l...
Despite significant progress in developing effective strategies for management of localized prost... more Despite significant progress in developing effective strategies for management of localized prostate cancer, the 5-year survival for metastatic castrate-resistant disease is less than 30%. Previous studies from our own and other laboratories showed the anti-tumorigenic potential of 2-Methoxyestradiol (2-ME 2 ) in various tumor models. Although variety of mechanisms including anti-angiogenic, pro-apoptotic, cell cycle deregulation has been reported to contribute to 2-ME 2 -mediated biological effects, the precise mechanism is unclear. To explore the role of 2-ME 2 , we carried out gene expression array analysis and discovered Recepteur d’Origine Nantais (RON) as one of the most significantly down regulated gene in response to 2-ME 2 treatment. Subsequently, RON was found to be significantly upregulated in advanced-stage PCA cell lines, which do not express androgen receptor (AR); and high-grade human prostate tumors. Stable silencing of RON in androgen independent, PTEN -/- PC3 cells showed noticeable changes in cell morphology, actin filament organization, as well as markers of epithelial-to-mesenchymal transition (EMT). In PTEN wild type DU145 cells, RON knockdown caused an increase in AR expression and promoter activity but decreased the transcriptional activation and expression of AR target genes such as PSA. In contrast, RON overexpression in androgen-responsive LNCAP cells leads to a suppression of the transcriptional activation of both AR and its downstream targets, including PSA. Furthermore, we found that RON silencing decreases expression and promoter activity of the anti-apoptotic protein FLICE-like inhibitory protein (FLIP) that is accompanied by the induction of apoptosis. In addition, intervention with 2-ME 2 reduced tumor growth that is accompanied with decreased RON expression in the prostate in transgenic adenocarcinoma of mouse prostate (TRAMP) model. These observations implicate RON as a hijacker of AR signaling that contributes in part to PCA growth. Therefore, restoration of native AR signaling via RON targeting could possibly be exploited in combination with antiandrogenic therapy to prevent recurrence of castrate-resistant prostate cancer. Supported by CA135451 (APK). Citation Format: Izhar Singh Batth, Peng Meng, Roble Bedolla, Robert E. Reddick, Addanki Pratap Kumar. RON-mediated hijacking of AR signaling in androgen-independent prostate cancer. [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 3315. doi:10.1158/1538-7445.AM2014-3315
Journal of immunology (Baltimore, Md. : 1950), 1999
Infections with intracellular pathogens such as Leishmania donovani and Mycobacterium tuberculosi... more Infections with intracellular pathogens such as Leishmania donovani and Mycobacterium tuberculosis pose serious health problems worldwide. Effective vaccines for these pathogens are not available. Furthermore, despite optimal therapy, disease progression is often seen with several intracellular infections. For these reasons, we initiated studies to develop novel anti-infective vaccine and treatment strategies that couple the potent Ag-presenting capacity of dendritic cells (DC) with paracrine delivery of potent anti-infective cytokines such as IL-12 to local immune response sites. We tested this strategy in a murine model of visceral leishmaniasis. Adoptive transfer of DCs pulsed ex vivo with soluble L. donovani Ags (SLDA) to naive mice induced the Ag-specific production of IFN-gamma, and increased the percentage of activation markers on spleen lymphocytes. SLDA-pulsed DCs engineered by retroviral gene transfer techniques to secrete high levels of biologically active murine IL-12 au...
NADPH reductase NAD(P)H:quinone oxidoreductase 1 (NQO1) is needed to maintain a cellular pool of ... more NADPH reductase NAD(P)H:quinone oxidoreductase 1 (NQO1) is needed to maintain a cellular pool of antioxidants, and this enzyme may contribute to tumorigenesis on the basis of studies in NQO1-deficient mice. In this work, we sought deeper insights into how NQO1 contributes to prostate carcinogenesis, a setting in which oxidative stress and inflammation are established contributors to disease development and progression. In the TRAMP mouse model of prostate cancer, NQO1 was highly expressed in tumor cells. NQO1 silencing in prostate cancer cells increased levels of nuclear IKKα and NF-κB while decreasing the levels of p53, leading to interactions between NF-κB and p300 that reinforce survival signaling. Gene expression analysis revealed upregulation of a set of immune-associated transcripts associated with inflammation and tumorigenesis in cells in which NQO1 was attenuated, with IL8 confirmed functionally in cell culture as one key NQO1-supported cytokine. Notably, NQO1-silenced pros...
Proceedings of the National Academy of Sciences, 2001
O 6 -methylguanine ( O 6 mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have... more O 6 -methylguanine ( O 6 mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have evolved with a DNA repair mechanism that largely ameliorates the deleterious effects of O 6 mG through a direct reversal mechanism by a protein termed O 6 -methylguanine-DNA methyltransferase (MGMT). However, the contribution of O 6 mG to carcinogenesis, in the absence of known exposure to agents that produce it, has not been defined. Nontransgenic C3HeB male mice have a high frequency of spontaneous liver tumors. Transgenic CeHeB/FeJ mice expressing human MGMT (hMGMT) were generated that had elevated hepatic MGMT activity. The spontaneous development of hepatocellular carcinoma was significantly reduced in those mice expressing hMGMT compared with nontransgenic C3HeB/FeJ male mice. No differences were detected in spontaneous mutant frequencies in lacI transgenes in mice carrying hMGMT compared with that without hMGMT but the proportion of GC to AT transition mutations was lower in the ...
There is growing evidence that chemokines and their receptors regulate the movement and in- terac... more There is growing evidence that chemokines and their receptors regulate the movement and in- teraction of antigen-presenting cells such as dendritic cells (DCs) and T cells. We tested the hy- pothesis that the CC chemokine receptor (CCR)2 and CCR5 and the chemokine macrophage inflammatory protein (MIP)-1 a , a ligand for CCR5, influence DC migration and localization. We found that deficiency of CCR2 but not CCR5 or MIP-1 a led to distinct defects in DC bi- ology. Langerhans cell (skin DC) density in CCR2-null mice was normal, and their ability to migrate into the dermis was intact; however, their migration to the draining lymph nodes was markedly impaired. CCR2-null mice had lower numbers of DCs in the spleen, and this was primarily due to a reduction in the CD8 a 1 T helper cell type 1 (Th1)-inducing subset of DCs. Additionally, there was a block in the Leishmania major infection-induced relocalization of splenic DCs from the marginal zone to the T cell areas. We propose that these ...
There is growing evidence that chemokines and their receptors regulate the movement and interacti... more There is growing evidence that chemokines and their receptors regulate the movement and interaction of antigen-presenting cells such as dendritic cells (DCs) and T cells. We tested the hypothesis that the CC chemokine receptor (CCR)2 and CCR5 and the chemokine macrophage inflammatory protein (MIP)-1α, a ligand for CCR5, influence DC migration and localization. We found that deficiency of CCR2 but not CCR5 or MIP-1α led to distinct defects in DC biology. Langerhans cell (skin DC) density in CCR2-null mice was normal, and their ability to migrate into the dermis was intact; however, their migration to the draining lymph nodes was markedly impaired. CCR2-null mice had lower numbers of DCs in the spleen, and this was primarily due to a reduction in the CD8α1 T helper cell type 1 (Th1)-inducing subset of DCs. Additionally, there was a block in the Leishmania major infection–induced relocalization of splenic DCs from the marginal zone to the T cell areas. We propose that these DC defects,...
We observed the repair process of the choriocapillaris after confluent argon laser retinal photoc... more We observed the repair process of the choriocapillaris after confluent argon laser retinal photocoagulation in the domestic cat with a plastic injection-corrosion technique coupled with scanning electron microscopy and transmission electron microscopy. Confluent photocoagulation was applied to the area of the retinal tapetum, creating two kinds of lesions: one consisted of five confluent burns and the other of 20 confluent burns. Specimens were prepared at 1, 30, and 60 days. Occlusion of the choriocapillaris was noted regardless of the length of time after photocoagulation. The only sign of repair was noted at 60 days when the choriocapillaris located at the edge of the lesion showed a uniform rearrangement. Transmission electron microscopy revealed severe damage to the endothelial cells, with lack of cell activation and permanent capillary closure in the vessels of the lesion proper.
Cancer prevention research (Philadelphia, Pa.), Jan 14, 2015
Hepatocellular carcinoma (HCC) is increasingly important in the United States as the incidence ra... more Hepatocellular carcinoma (HCC) is increasingly important in the United States as the incidence rate rose over the last 30 years. C3HeB/FeJ mice serve as a unique model to study HCC tumorigenesis because they mimic human HCC with delayed onset, male gender bias, a ~50% incidence, and susceptibility to tumorigenesis is mediated through multiple genetic loci. Because a human O6-methylguanine-DNA methyltransferase (hMGMT) transgene reduces spontaneous tumorigenesis in this model, we hypothesized that hMGMT would also protect from methylation-induced hepatocarcinogenesis. To test this hypothesis, wild type and hMGMT transgenic C3HeB/FeJ male mice were treated with two monofunctional alkylating agents: diethylnitrosamine (DEN) (0.025 µmol/g body weight) on day 12 of life with evaluation for glucose-6-phosphatase deficient (G6PD) foci at 16, 24, and 32 weeks or N-methyl-N-nitrosurea (MNU) (25 mg MNU/kg body weight) once monthly for 7 months starting at 3 months of age with evaluation for l...
Despite significant progress in developing effective strategies for management of localized prost... more Despite significant progress in developing effective strategies for management of localized prostate cancer, the 5-year survival for metastatic castrate-resistant disease is less than 30%. Previous studies from our own and other laboratories showed the anti-tumorigenic potential of 2-Methoxyestradiol (2-ME 2 ) in various tumor models. Although variety of mechanisms including anti-angiogenic, pro-apoptotic, cell cycle deregulation has been reported to contribute to 2-ME 2 -mediated biological effects, the precise mechanism is unclear. To explore the role of 2-ME 2 , we carried out gene expression array analysis and discovered Recepteur d’Origine Nantais (RON) as one of the most significantly down regulated gene in response to 2-ME 2 treatment. Subsequently, RON was found to be significantly upregulated in advanced-stage PCA cell lines, which do not express androgen receptor (AR); and high-grade human prostate tumors. Stable silencing of RON in androgen independent, PTEN -/- PC3 cells showed noticeable changes in cell morphology, actin filament organization, as well as markers of epithelial-to-mesenchymal transition (EMT). In PTEN wild type DU145 cells, RON knockdown caused an increase in AR expression and promoter activity but decreased the transcriptional activation and expression of AR target genes such as PSA. In contrast, RON overexpression in androgen-responsive LNCAP cells leads to a suppression of the transcriptional activation of both AR and its downstream targets, including PSA. Furthermore, we found that RON silencing decreases expression and promoter activity of the anti-apoptotic protein FLICE-like inhibitory protein (FLIP) that is accompanied by the induction of apoptosis. In addition, intervention with 2-ME 2 reduced tumor growth that is accompanied with decreased RON expression in the prostate in transgenic adenocarcinoma of mouse prostate (TRAMP) model. These observations implicate RON as a hijacker of AR signaling that contributes in part to PCA growth. Therefore, restoration of native AR signaling via RON targeting could possibly be exploited in combination with antiandrogenic therapy to prevent recurrence of castrate-resistant prostate cancer. Supported by CA135451 (APK). Citation Format: Izhar Singh Batth, Peng Meng, Roble Bedolla, Robert E. Reddick, Addanki Pratap Kumar. RON-mediated hijacking of AR signaling in androgen-independent prostate cancer. [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 3315. doi:10.1158/1538-7445.AM2014-3315
Journal of immunology (Baltimore, Md. : 1950), 1999
Infections with intracellular pathogens such as Leishmania donovani and Mycobacterium tuberculosi... more Infections with intracellular pathogens such as Leishmania donovani and Mycobacterium tuberculosis pose serious health problems worldwide. Effective vaccines for these pathogens are not available. Furthermore, despite optimal therapy, disease progression is often seen with several intracellular infections. For these reasons, we initiated studies to develop novel anti-infective vaccine and treatment strategies that couple the potent Ag-presenting capacity of dendritic cells (DC) with paracrine delivery of potent anti-infective cytokines such as IL-12 to local immune response sites. We tested this strategy in a murine model of visceral leishmaniasis. Adoptive transfer of DCs pulsed ex vivo with soluble L. donovani Ags (SLDA) to naive mice induced the Ag-specific production of IFN-gamma, and increased the percentage of activation markers on spleen lymphocytes. SLDA-pulsed DCs engineered by retroviral gene transfer techniques to secrete high levels of biologically active murine IL-12 au...
NADPH reductase NAD(P)H:quinone oxidoreductase 1 (NQO1) is needed to maintain a cellular pool of ... more NADPH reductase NAD(P)H:quinone oxidoreductase 1 (NQO1) is needed to maintain a cellular pool of antioxidants, and this enzyme may contribute to tumorigenesis on the basis of studies in NQO1-deficient mice. In this work, we sought deeper insights into how NQO1 contributes to prostate carcinogenesis, a setting in which oxidative stress and inflammation are established contributors to disease development and progression. In the TRAMP mouse model of prostate cancer, NQO1 was highly expressed in tumor cells. NQO1 silencing in prostate cancer cells increased levels of nuclear IKKα and NF-κB while decreasing the levels of p53, leading to interactions between NF-κB and p300 that reinforce survival signaling. Gene expression analysis revealed upregulation of a set of immune-associated transcripts associated with inflammation and tumorigenesis in cells in which NQO1 was attenuated, with IL8 confirmed functionally in cell culture as one key NQO1-supported cytokine. Notably, NQO1-silenced pros...
Uploads
Papers by robert reddick