Human mesenchymal stem cells （hMSCs） can home to tumor sites and inhibit the growth of tumor cells. Little is known about the underlying molecular mechanisms that link hMSCs to the targeted inhibition of tumor cells...Human mesenchymal stem cells （hMSCs） can home to tumor sites and inhibit the growth of tumor cells. Little is known about the underlying molecular mechanisms that link hMSCs to the targeted inhibition of tumor cells. In this study, we investigated the effects of hMSCs on two human hepatoma cell lines （H7402 and HepG2） using an animal transplantation model, a co-culture system and conditioned media from hMSCs. Animal transplantation studies showed that the latent time for tumor formation was prolonged and that the tumor size was smaller when SCID mice were injected with H7402 cells and an equal number of Z3 hMSCs. When co-cultured with Z3 cells, H7402 cell proliferation decreased, apoptosis increased, and the expression of Bcl-2, c-Myc, proliferating cell nuclear antigen （PCNA） and survivin was downregulated. After treatment with conditioned media derived from Z3 hMSC cultures, H4702 cells showed decreased colony-forming ability and decreased proliferation. Immunoblot analysis showed that β-catenin, Bcl-2, c-Myc, PCNA and survivin expression was downregulated in H7402 and HepG2 cells. Taken together, our findings demonstrate that hMSCs inhibit the malignant phenotypes of the H7402 and HepG2 human liver cancer cell lines, which include proliferation, colony-forming ability and oncogene expression both in vitro and in vivo. Furthermore, our studies provide evidence that the Wnt signaling pathway may have a role in hMSC-mediated targeting and tumor cell inhibition.展开更多
The primary Syrian hamster embryo(SHE) cells were used to study the oncogenic transformation by ￣(238)pu α particles or X-rays alone or in combination with a chemical promoter phorbol ester.Survival curves of SHE ce...The primary Syrian hamster embryo(SHE) cells were used to study the oncogenic transformation by ￣(238)pu α particles or X-rays alone or in combination with a chemical promoter phorbol ester.Survival curves of SHE cells following exposure to α-particles or X-rays were fitted to single-or multi-target models,respectively. Model parameters were: Do = 0. 55 Gy. n = 1 for α particles 4 Do = 1.44 Gy. Dq = 3.0 Gy. n=7.7 for X-rays.Incidence of α particles or X-rays induced cell transformation was dose-dependant.α particles were more efficient in inducing cell transformation than that of X-rays. The enhancement of SHE cell transformation by phorbol 12-myristate 13-acetate(PMA) following exposure to α particles of 0. 25-1. 00 Gy was observed.展开更多
AIM： To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model. METHODS： To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine （...AIM： To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model. METHODS： To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine （5-FC）, we generated a chimeric bifunctional SuperCD suicide gene, a fusion of the yeast cytosine deaminase （YCD） and the yeast uracil phosphoribosyltransferase （YUPRT） gene. RESULTS： In vitro stably transduced Morris rat hepatoma cells （MH） expressing the bifunctional SuperCD suicide gene （MH SuperCD） showed a clearly marked enhancement in cell killing when incubated with 5-FC as compared with MH cells stably expressing YCD solely （MH YCD） or the cytosine deaminase gene of bacterial origin （MH BCD）, respectively. In vivo, MH SuperCD tumors implanted both subcutaneously as well as orthotopically into the livers of syngeneic ACI rats demonstrated significant tumor regressions （P〈0.01） under both high dose as well as low dose systemic 5-FC application, whereas MH tumors without transgene expression （MH naive） showed rapid progression. For the first time, an order of in vivo suicide gene effectiveness （SuperCD〉〉 YCD〉〉BCD〉〉〉negative control） was defined as a result of a direct in vivo comparison of all three suicide genes. CONCLUSION： Bifunctional SuperCD suicide gene expression is highly effective in a rat hepatoma model, thereby significantly improving both the therapeutic index and the efficacy of hepatocellular carcinoma killing by fluorocytosine.展开更多
Boanmycin (bleomycin A6 . BM) . an antitumor antibiotic, was conjugated to monoclonal antibodies including R19, H 111 and CCT2. The immunoconjugates exhibited selective cytotoxicity to related target cells including c...Boanmycin (bleomycin A6 . BM) . an antitumor antibiotic, was conjugated to monoclonal antibodies including R19, H 111 and CCT2. The immunoconjugates exhibited selective cytotoxicity to related target cells including cecum cancer Hce-8693 cells, liver cancer BEL-7402 cells and leukemia CEM cells. They were highly effective against related human tumor xenografts in nude mice, and the inhibition rates by the conjugates were much higher than those by free BM. The inhibition rate by R19-BM conjugate against human cecum cancer xenografts reached 90%. BY immunoelectron microscopy, CCT2-BM conjugate showed specific binding and internalization in leukemia CEM cells. The results indicate that boanmycin-monoclonal antibody immunoconjugates are highly active both in vitro and in vivo.展开更多
The highly conserved domain （exon 5-8） of p53 gene in transformed rat tracheal epithelial （RTE） cells was analyzed by means of polymerase chain reaction and single strand con formation polymorphism （PCR-SSCP）. T...The highly conserved domain （exon 5-8） of p53 gene in transformed rat tracheal epithelial （RTE） cells was analyzed by means of polymerase chain reaction and single strand con formation polymorphism （PCR-SSCP）. The result showed that single strand of exon 8 gene had mobility shift in polyacrylamide nondenaturing gel. DNA sequencing proved the mutation was G→C transversion at condon 265.展开更多
Esophageal cancer has been reported as the ninth most common malignancy and ranks as the sixth most frequent cause of death worldwide. Esophageal cancer treatment involves surgery, chemotherapy, radiation therapy, or ...Esophageal cancer has been reported as the ninth most common malignancy and ranks as the sixth most frequent cause of death worldwide. Esophageal cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy. Novel strategies are needed to boost the oncologic outcome. Recent advances in the molecular biology of esophageal cancer have documented the role of genetic alterations in tumorigenesis. Oncogenes serve a pivotal function in tumorigenesis. Targeted therapies are directed at the unique molecular signature of cancer cells for enhanced efficacy with low toxicity. RNA interference(RNAi) technology is a powerful tool for silencing endogenous or exogenous genes in mammalian cells. Related results have shown that targeting oncogenes with siRNAs, specifically the mRNA, effectively reduces tumor cell proliferation and induces apoptotic cell death. This article will briefly review studies on silencing tumor enhancer genes related to the induction of esophageal cancer.展开更多
基金This work was supported by grants from the National Basic Research Program of China （973 Program, No. 2007CB914800 to Xiaodong Zhang）, National Natural Science Foundation of China （No. 30570698 to Xiaodong Zhang） and Tianjin Natural Scientific Foundation （No. 033801211 to Xiaodong Zhang）.
文摘Human mesenchymal stem cells （hMSCs） can home to tumor sites and inhibit the growth of tumor cells. Little is known about the underlying molecular mechanisms that link hMSCs to the targeted inhibition of tumor cells. In this study, we investigated the effects of hMSCs on two human hepatoma cell lines （H7402 and HepG2） using an animal transplantation model, a co-culture system and conditioned media from hMSCs. Animal transplantation studies showed that the latent time for tumor formation was prolonged and that the tumor size was smaller when SCID mice were injected with H7402 cells and an equal number of Z3 hMSCs. When co-cultured with Z3 cells, H7402 cell proliferation decreased, apoptosis increased, and the expression of Bcl-2, c-Myc, proliferating cell nuclear antigen （PCNA） and survivin was downregulated. After treatment with conditioned media derived from Z3 hMSC cultures, H4702 cells showed decreased colony-forming ability and decreased proliferation. Immunoblot analysis showed that β-catenin, Bcl-2, c-Myc, PCNA and survivin expression was downregulated in H7402 and HepG2 cells. Taken together, our findings demonstrate that hMSCs inhibit the malignant phenotypes of the H7402 and HepG2 human liver cancer cell lines, which include proliferation, colony-forming ability and oncogene expression both in vitro and in vivo. Furthermore, our studies provide evidence that the Wnt signaling pathway may have a role in hMSC-mediated targeting and tumor cell inhibition.
文摘The primary Syrian hamster embryo(SHE) cells were used to study the oncogenic transformation by ￣(238)pu α particles or X-rays alone or in combination with a chemical promoter phorbol ester.Survival curves of SHE cells following exposure to α-particles or X-rays were fitted to single-or multi-target models,respectively. Model parameters were: Do = 0. 55 Gy. n = 1 for α particles 4 Do = 1.44 Gy. Dq = 3.0 Gy. n=7.7 for X-rays.Incidence of α particles or X-rays induced cell transformation was dose-dependant.α particles were more efficient in inducing cell transformation than that of X-rays. The enhancement of SHE cell transformation by phorbol 12-myristate 13-acetate(PMA) following exposure to α particles of 0. 25-1. 00 Gy was observed.
基金Supported by grants from German Research Foundation (LA649-20-2)Federal Ministry of Education, Science, Research and Technology (Fo. 01KS9602, Fo. 01KV9532)Interdisciplinary Clinical Research Center (IZKF) Tubingen, and the fortune-program of the Medical Faculty of Eberhard-Karls-University Tubingen (F. 1281127)W.A.W. supported by a scholarship from Pinguin Foundation (Henkel KGaA)
文摘AIM： To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model. METHODS： To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine （5-FC）, we generated a chimeric bifunctional SuperCD suicide gene, a fusion of the yeast cytosine deaminase （YCD） and the yeast uracil phosphoribosyltransferase （YUPRT） gene. RESULTS： In vitro stably transduced Morris rat hepatoma cells （MH） expressing the bifunctional SuperCD suicide gene （MH SuperCD） showed a clearly marked enhancement in cell killing when incubated with 5-FC as compared with MH cells stably expressing YCD solely （MH YCD） or the cytosine deaminase gene of bacterial origin （MH BCD）, respectively. In vivo, MH SuperCD tumors implanted both subcutaneously as well as orthotopically into the livers of syngeneic ACI rats demonstrated significant tumor regressions （P〈0.01） under both high dose as well as low dose systemic 5-FC application, whereas MH tumors without transgene expression （MH naive） showed rapid progression. For the first time, an order of in vivo suicide gene effectiveness （SuperCD〉〉 YCD〉〉BCD〉〉〉negative control） was defined as a result of a direct in vivo comparison of all three suicide genes. CONCLUSION： Bifunctional SuperCD suicide gene expression is highly effective in a rat hepatoma model, thereby significantly improving both the therapeutic index and the efficacy of hepatocellular carcinoma killing by fluorocytosine.
文摘Boanmycin (bleomycin A6 . BM) . an antitumor antibiotic, was conjugated to monoclonal antibodies including R19, H 111 and CCT2. The immunoconjugates exhibited selective cytotoxicity to related target cells including cecum cancer Hce-8693 cells, liver cancer BEL-7402 cells and leukemia CEM cells. They were highly effective against related human tumor xenografts in nude mice, and the inhibition rates by the conjugates were much higher than those by free BM. The inhibition rate by R19-BM conjugate against human cecum cancer xenografts reached 90%. BY immunoelectron microscopy, CCT2-BM conjugate showed specific binding and internalization in leukemia CEM cells. The results indicate that boanmycin-monoclonal antibody immunoconjugates are highly active both in vitro and in vivo.
文摘The highly conserved domain （exon 5-8） of p53 gene in transformed rat tracheal epithelial （RTE） cells was analyzed by means of polymerase chain reaction and single strand con formation polymorphism （PCR-SSCP）. The result showed that single strand of exon 8 gene had mobility shift in polyacrylamide nondenaturing gel. DNA sequencing proved the mutation was G→C transversion at condon 265.
文摘Esophageal cancer has been reported as the ninth most common malignancy and ranks as the sixth most frequent cause of death worldwide. Esophageal cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy. Novel strategies are needed to boost the oncologic outcome. Recent advances in the molecular biology of esophageal cancer have documented the role of genetic alterations in tumorigenesis. Oncogenes serve a pivotal function in tumorigenesis. Targeted therapies are directed at the unique molecular signature of cancer cells for enhanced efficacy with low toxicity. RNA interference(RNAi) technology is a powerful tool for silencing endogenous or exogenous genes in mammalian cells. Related results have shown that targeting oncogenes with siRNAs, specifically the mRNA, effectively reduces tumor cell proliferation and induces apoptotic cell death. This article will briefly review studies on silencing tumor enhancer genes related to the induction of esophageal cancer.
