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Akt Cell Survival Pathway Gene Therapy Supplemented with Plant Sterol Diet for Prostate Cancer Treatment
CANCER-APOPTOSIS AND SUICIDE 934. Gene Therapy for Colon Cancer by AdenoAssociated Viral Vector-Mediated Transfer of Apolipoprotein(a) Kringles Kyuhyun Lee,1 Seong-Tae Yun,1 Hong-Kyu Lee,1 Eui-Cheol Jo.1 1 Gene Therapy Team, Biomolecular Engineering Division, MOGAM Biotechnology Research Institute, Yongin, Kyonggi-Do, Republic of Korea. We previously demonstrated the anti-angiogenic activities of apolipoprotein (a) (apo (a)) kringles LK68 and LK8 in vitro and in vivo. Gene transfer of these kringles mediated by adeno-associated viral vectors (AAV) further elucidated a potential anti-metastatic and anti-tumor activity of LK68 and LK8 in vivo. In the present study, we further evaluated the therapeutic potential of gene therapy with recombinant AAV carrying LK68 gene (rAAV-LK68) in the treatment of colon cancer. Intramuscular administration of rAAVLK68 (1 ×109 infectious units/mouse) appeared to extend the latent period of the tumors and reduced the rate of tumor growth, compared to the negative control groups. rAAV-produced LK68 inhibited tumor growth by more than 65% (P<0.0069 versus each negative control group) in immuno-deficient mice bearing subcutaneously transplanted human colon tumor cells. Furthermore, rAAV-LK68 administration reduced by 85% (P<0.0094 versus each negative control group) the number of tumor nodules metastasized to the liver, when evaluated in a murine hepatic metastasis model. Histological and immunohistochemical analyses of the tumor sections showed that rAAV-produced LK68 inhibited tumor angiogenesis by more than 60% (P<0.01 versus negative control group) and triggered threefold more tumor apoptosis, compared to the negative control. Therefore, anti-angiogenecity induced by rAAVLK68 administration was presumed to trigger suppression of tumor growth and metastasis. These results collectively suggest that rAAVLK68 is a potent agent to inhibit tumor growth and hepatic metastasis of human colon cancer. Eui-Cheol Jo is the principal investigator of the research funded by the MOCIE grant aforementioned.
935. Anti-PI3K/Akt Cell Survival Pathway Gene Therapy Supplemented with Plant Sterol Diet for Prostate Cancer Treatment Jun Zhang,1 Yi Lu.1 Medicine, University of Tennessee Health Science Center, Memphis, TN.
1
Prostate cancer is the most frequently diagnosed malignancy and the second leading cause of cancer deaths in American men today. The dietary animal and plant sterols appear to play critical roles in prostate cancer formation/progression, or prevention, respectively. Cholesterol, the animal sterol that is enriched in red meat and dietary fat, is implicated in promoting prostate cancer formation and progression. On the other hand, plant sterols (such as ß-sitosterol or ß-SIT) that are enriched in nuts, cereals and soy products, induce cancer cells to apoptosis and inhibit tumor formation and progression. To examine whether dietary sterols have effects on prostate cancer cell proliferation and migration, we treated human prostate cancer PC-3 and DU145 cells with cholesterol and ß-SIT for 4 days. We found that ß-SIT effectively inhibited cell proliferation of PC-3 and DU145 cells at 38.3% and 36.3%, respectively, when compared to untreated control cells, whereas cholesterol stimulated proliferation of PC-3 and DU145 cells, at 50% and 62.5%, respectively. Moreover, ß-SIT also inhibited migration of PC-3 and DU145 cells, at 80.9%
Molecular Therapy Volume 13, Supplement 1, May 2006 Copyright The American Society of Gene Therapy
and 18.0%, respectively, when compared to the control cells. In contrast, cholesterol stimulated migration of PC-3 and DU145 cells, at 33. 8% and 23.8%, respectively. In an animal study, mice fed with cholesterol-rich diet had a larger implanted xenograft C4-2B prostate tumor and increased tumor progression in terms of metastasis to the bone, by comparing with control mice fed with regular diet, whereas mice fed with plant sterol-rich diet had a smaller C4-2B xenograft tumor and decreased tumor progression. Activation of phosphoinositide 3 kinase (PI3K)/Akt pathway protects cancer cells from apoptosis induced by anticancer therapies and chemotherapeutic agents. Activity of PI3K/Akt kinases is often increased in prostate cancer and is associated with poor prognosis. To test whether blocking of PI3K/Akt cell survival pathway would sensitize prostate cancer cells to ß-SIT mediated apoptosis, a recombinant adenoviral viral vector, Ad-PI3K-DN, which expresses a PI3K dominant-negative mutant, was generated. In vitro assays demonstrated that Ad-PI3K-DN effectively inhibited PC-3 cell growth. To examine the combinative anti-tumor effects by Ad-PI3KDN and plant sterol diet, we treated mice with implanted C4-2B prostate tumor with both plant sterol diet and Ad-PI3K-DN. An additive inhibitory effect was observed in mouse group treated with both plant sterol diet and Ad-PI3K-DN. In summary, our results showed that plant sterols inhibit prostate cancer proliferation and migration in vitro and tumor progression in vivo. Gene therapy targeting PI3K/Akt cell survival pathway effectively inhibits prostate cancer growth. A novel approach is being investigated for effective treatment of prostate cancer by combining gene therapy in blocking cancer cell survival pathway and diet supplement in prevention of tumor progression. This research is supported by Cancer Research and Prevention Foundation.
936. Novel Oncolytic HSV-1 Mutant Expressing ICP 34.5 under the Transcriptional Control of Musashi1 Promoter for the Treatment of Gliomas Takahito Yazaki,1 Ryuichi Kanai,1 Hideyuki Okano,2 Takeshi Kawase.1 1 Department of Neurosurgery, School of Medicine, Keio University, Tokyo, Japan; 2Department of Physiology, School of Medicine, Keio University, Tokyo, Japan. Although HSV-1 mutants possessing deletions in both copies of the ICP134.5 gene have been proven safe through a number of animal experiments and clinical trials, their therapeutic efficacy was also markedly reduced. In order to overcome this situation, we concentrated on the use of tumor-specific promoter in this study, to express ICP34.5 selectively in malignant glioma cells. As a molecular marker for malignant glioma, we focused on the neural RNA binding protein, Musashi1. Based on the results of defective vector dvM345, as reported earlier, we created, via homologous recombination, a novel HSV-1 vector termed KeM34.5, which expresses ICP34.5 under the transcriptional control of Musashi1gene promoter (P/ musashi1). Cytotoxicity mediated by KeM34.5 was significantly enhanced in human glioma cell lines (U87MG, U87MG-E6, U251, and T98G), resulting in about 2 log increase of viral yield, compared to its parental vector G207. This virus showed a much higher therapeutic efficacy also in the in vivo glioma model, while maintaining the desirable neuroattenuated phenotype. These results suggest that the oncolytic HSV-1 expressing ICP34.5 under the transcriptional control of Musashi1 gene promoter can be a promising therapeutic agent for the treatment of malignant glioma.
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935. Anti-PI3K/Akt Cell Survival Pathway Gene Therapy Supplemented with Plant Sterol Diet for Prostate Cancer Treatment Jun Zhang,1 Yi Lu.1 Medicine, University of Tennessee Health Science Center, Memphis, TN.
1
Prostate cancer is the most frequently diagnosed malignancy and the second leading cause of cancer deaths in American men today. The dietary animal and plant sterols appear to play critical roles in prostate cancer formation/progression, or prevention, respectively. Cholesterol, the animal sterol that is enriched in red meat and dietary fat, is implicated in promoting prostate cancer formation and progression. On the other hand, plant sterols (such as ß-sitosterol or ß-SIT) that are enriched in nuts, cereals and soy products, induce cancer cells to apoptosis and inhibit tumor formation and progression. To examine whether dietary sterols have effects on prostate cancer cell proliferation and migration, we treated human prostate cancer PC-3 and DU145 cells with cholesterol and ß-SIT for 4 days. We found that ß-SIT effectively inhibited cell proliferation of PC-3 and DU145 cells at 38.3% and 36.3%, respectively, when compared to untreated control cells, whereas cholesterol stimulated proliferation of PC-3 and DU145 cells, at 50% and 62.5%, respectively. Moreover, ß-SIT also inhibited migration of PC-3 and DU145 cells, at 80.9%
Molecular Therapy Volume 13, Supplement 1, May 2006 Copyright The American Society of Gene Therapy
and 18.0%, respectively, when compared to the control cells. In contrast, cholesterol stimulated migration of PC-3 and DU145 cells, at 33. 8% and 23.8%, respectively. In an animal study, mice fed with cholesterol-rich diet had a larger implanted xenograft C4-2B prostate tumor and increased tumor progression in terms of metastasis to the bone, by comparing with control mice fed with regular diet, whereas mice fed with plant sterol-rich diet had a smaller C4-2B xenograft tumor and decreased tumor progression. Activation of phosphoinositide 3 kinase (PI3K)/Akt pathway protects cancer cells from apoptosis induced by anticancer therapies and chemotherapeutic agents. Activity of PI3K/Akt kinases is often increased in prostate cancer and is associated with poor prognosis. To test whether blocking of PI3K/Akt cell survival pathway would sensitize prostate cancer cells to ß-SIT mediated apoptosis, a recombinant adenoviral viral vector, Ad-PI3K-DN, which expresses a PI3K dominant-negative mutant, was generated. In vitro assays demonstrated that Ad-PI3K-DN effectively inhibited PC-3 cell growth. To examine the combinative anti-tumor effects by Ad-PI3KDN and plant sterol diet, we treated mice with implanted C4-2B prostate tumor with both plant sterol diet and Ad-PI3K-DN. An additive inhibitory effect was observed in mouse group treated with both plant sterol diet and Ad-PI3K-DN. In summary, our results showed that plant sterols inhibit prostate cancer proliferation and migration in vitro and tumor progression in vivo. Gene therapy targeting PI3K/Akt cell survival pathway effectively inhibits prostate cancer growth. A novel approach is being investigated for effective treatment of prostate cancer by combining gene therapy in blocking cancer cell survival pathway and diet supplement in prevention of tumor progression. This research is supported by Cancer Research and Prevention Foundation.
936. Novel Oncolytic HSV-1 Mutant Expressing ICP 34.5 under the Transcriptional Control of Musashi1 Promoter for the Treatment of Gliomas Takahito Yazaki,1 Ryuichi Kanai,1 Hideyuki Okano,2 Takeshi Kawase.1 1 Department of Neurosurgery, School of Medicine, Keio University, Tokyo, Japan; 2Department of Physiology, School of Medicine, Keio University, Tokyo, Japan. Although HSV-1 mutants possessing deletions in both copies of the ICP134.5 gene have been proven safe through a number of animal experiments and clinical trials, their therapeutic efficacy was also markedly reduced. In order to overcome this situation, we concentrated on the use of tumor-specific promoter in this study, to express ICP34.5 selectively in malignant glioma cells. As a molecular marker for malignant glioma, we focused on the neural RNA binding protein, Musashi1. Based on the results of defective vector dvM345, as reported earlier, we created, via homologous recombination, a novel HSV-1 vector termed KeM34.5, which expresses ICP34.5 under the transcriptional control of Musashi1gene promoter (P/ musashi1). Cytotoxicity mediated by KeM34.5 was significantly enhanced in human glioma cell lines (U87MG, U87MG-E6, U251, and T98G), resulting in about 2 log increase of viral yield, compared to its parental vector G207. This virus showed a much higher therapeutic efficacy also in the in vivo glioma model, while maintaining the desirable neuroattenuated phenotype. These results suggest that the oncolytic HSV-1 expressing ICP34.5 under the transcriptional control of Musashi1 gene promoter can be a promising therapeutic agent for the treatment of malignant glioma.
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