Project description:Gene-expression profiles of rat liver cirrhosis induced by diethylnitrosamine and the effect of erlotinib on liver fibrogenesis and liver cancer development Hepatocellular carcinoma (HCC) is the sixth most common solid tumor worldwide and the third leading cause of cancer-related death. Given the lack of successful treatment options, chemoprevention in high-risk patients has been proposed as an alternative strategy. Mounting evidence supports a role for epidermal growth factor (EGF) during chronic liver disease and hepatocellular transformation. We address the hypothesis that blocking the EGF-EGF receptor (EGFR) pathway may be an effective strategy for inhibiting fibrogenesis and hepatocarcinogenesis. A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the effects of erlotinib on underlying chronic liver disease and HCC formation. The DEN-induced rat model closely resembles disease progression in humans both pathologically and molecularly. Erlotinib significantly prevented the development of HCC tumor nodules in a dose-dependent fashion. Further, erlotinib inhibited the activation of hepatic stellate cells and prevented fibrogenesis. Erlotinib also reduced hepatotoxicity and improved liver function. Finally, a gene expression signature predictive of poor survival in human cirrhosis patients was reversed in response to erlotinib. Our data demonstrate for the first time that EGFR inhibition prevents liver fibrogenesis. Further, our results suggest that erlotinib is a potentially effective HCC chemoprevention strategy through inhibition of cirrhosis progression which can be monitored at the molecular level. Keywords: Cirrhotic liver, Expression array, Illumina, Signatures, Outcome prediction Animals received humane care according to the criteria outlined in the M-bM-^@M-^\Guide for the Care and Use of Laboratory AnimalsM-bM-^@M-^] of the National Academy of Sciences. All animals were maintained in accordance with the institutional guidelines of the Massachusetts General Hospital Subcommittee on Research Animal Care. Male Wistar rats received weekly IP injections of diethylnitrosamine (DEN) at 50 mg/kg, 100mg/kg, or vehicle control (PBS) for 18 weeks. A subset of rats received either daily (5X a week) IP injections of 2 mg/kg erlotinib or vehicle control during weeks 13 - 18. In a separate study, the erlotinib dose was lowered to 0.5 mg/kg. The vehicle groups from the two studies were not significantly different so they were combined together for analysis. Rats were weighed at the end of each week. Animals were sacrificed at 9, 13 and 19 weeks after a one-week washout period to eliminate acute effects of DEN. At the time of sacrifice, the non-tumor liver tissues were collected in RNase-free tubes and snap-frozen in liquid nitrogen. Frozen tissues were stored at -80M-BM-0C until RNA extraction.

Project description:Gene-expression profiles of rat hepatocellular carcinoma induced by diethylnitrosamine (DEN) and the effect of erlotinib Hepatocellular carcinoma (HCC) is the sixth most common solid tumor worldwide and the third leading cause of cancer-related death. Given the lack of successful treatment options, chemoprevention in high-risk patients has been proposed as an alternative strategy. Mounting evidence supports a role for epidermal growth factor (EGF) during chronic liver disease and hepatocellular transformation. We address the hypothesis that blocking the EGF-EGF receptor (EGFR) pathway may be an effective strategy for inhibiting fibrogenesis and hepatocarcinogenesis. A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the effects of erlotinib on underlying chronic liver disease and HCC formation. The DEN-induced rat model closely resembles disease progression in humans both pathologically and molecularly. Erlotinib significantly prevented the development of HCC tumor nodules in a dose-dependent fashion. Further, erlotinib inhibited the activation of hepatic stellate cells and prevented fibrogenesis. Erlotinib also reduced hepatotoxicity and improved liver function. Finally, a gene expression signature predictive of poor survival in human cirrhosis patients was reversed in response to erlotinib. Our data demonstrate for the first time that EGFR inhibition prevents liver fibrogenesis. Further, our results suggest that erlotinib is a potentially effective HCC chemoprevention strategy through inhibition of cirrhosis progression which can be monitored at the molecular level. Animals received humane care according to the criteria outlined in the M-bM-^@M-^\Guide for the Care and Use of Laboratory AnimalsM-bM-^@M-^] of the National Academy of Sciences. All animals were maintained in accordance with the institutional guidelines of the Massachusetts General Hospital Subcommittee on Research Animal Care. Male Wistar rats received weekly IP injections of diethylnitrosamine (DEN) at 50 mg/kg, 100mg/kg, or vehicle control (PBS) for 18 weeks. A subset of rats received either daily (5X a week) IP injections of 2 mg/kg erlotinib or vehicle control during weeks 13 - 18. In a separate study, the erlotinib dose was lowered to 0.5 mg/kg. The vehicle groups from the two studies were not significantly different so they were combined together for analysis. Rats were weighed at the end of each week. Animals were sacrificed at 9, 13 and 19 weeks after a one-week washout period to eliminate acute effects of DEN. At the time of sacrifice, the non-tumor liver tissues were collected in RNase-free tubes and snap-frozen in liquid nitrogen. Frozen tissues were stored at -80M-BM-0C until RNA extraction.

Project description:Gene-expression profiles of liver tissue of cabon tetrachloride (CCl4)-treated mouse and the effect of erlotinib Hepatocellular carcinoma (HCC) is the sixth most common solid tumor worldwide and the third leading cause of cancer-related death. Given the lack of successful treatment options, chemoprevention in high-risk patients has been proposed as an alternative strategy. Mounting evidence supports a role for epidermal growth factor (EGF) during chronic liver disease and hepatocellular transformation. We address the hypothesis that blocking the EGF-EGF receptor (EGFR) pathway may be an effective strategy for inhibiting fibrogenesis and hepatocarcinogenesis. A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the effects of erlotinib on underlying chronic liver disease and HCC formation. The DEN-induced rat model closely resembles disease progression in humans both pathologically and molecularly. Erlotinib significantly prevented the development of HCC tumor nodules in a dose-dependent fashion. Further, erlotinib inhibited the activation of hepatic stellate cells and prevented fibrogenesis. Erlotinib also reduced hepatotoxicity and improved liver function. Finally, a gene expression signature predictive of poor survival in human cirrhosis patients was reversed in response to erlotinib. Our data demonstrate for the first time that EGFR inhibition prevents liver fibrogenesis. Further, our results suggest that erlotinib is a potentially effective HCC chemoprevention strategy through inhibition of cirrhosis progression which can be monitored at the molecular level. Animals received humane care according to the criteria outlined in the M-bM-^@M-^\Guide for the Care and Use of Laboratory AnimalsM-bM-^@M-^] of the National Academy of Sciences. All animals were maintained in accordance with the institutional guidelines of the Massachusetts General Hospital Subcommittee on Research Animal Care. Strain A/J male mice (Jackson Laboratory, Bar Harbor, ME) were treated three times a week for 18 weeks with either 0.1cc of a 40 percent solution of CCl4 (Sigma) in olive oil or with vehicle control by oral gavage. Mice were sacrificed at 19 weeks after a one-week washout to eliminate acute effects of CCl4. The liver was sectioned and fixed in phosphate-buffered 10% formaldehyde for histological analysis. The remaining portions of the liver were collected in RNase-free tubes and snap-frozen in liquid nitrogen. Frozen tissues were stored at -80M-BM-0C until use.

Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone. Hepatic stellate cells were isolated from liver of beta-PDGFR-wild-type or knockout mice, and treated with beta-PDGF ligand or vehicle control.

Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone.

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Gene expression profile of liver tissue in low-dose, repeated diethylnitrosamine (DEN)-treated rat treated with epigallocatechin gallate (EGCG)

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