Project/Area Number |
08671054
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Radiation science
|
Research Institution | Jikei University school of Medicine |
Principal Investigator |
KAMADA Minori Jikei University school of Medicine Department of Microbiology Assistant, 医学部・微生物学講座第1, 助手 (90189259)
|
Project Period (FY) |
1996 – 1997
|
Project Status |
Completed (Fiscal Year 1997)
|
Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1996: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
Keywords | gene therapy / cancer / ionizing radiation / radioisotopes / Ga-67-citrate / EGR-1 promoter / human pancreatic tumor cell / Tc-99m / human glioblastoma cells / ganciclovir |
Research Abstract |
In investigation new methods for the tratment of malignant cancer, we have explored the possibility of using a combination of radiation and gene therapies. We demonstrate that the early growth response gene 1 promoter (Egr-1) is sufficient to confer selective expression of the luciferase gene (Lec) a human glioblastoma cells and human pancreatic tumor cell line (AsPc-1) when exposed to ionizing radiation. The Egr-1 promoter directed the radioindecible expression of luciferase, and yielded higher levels of Luc activity than that in non irradiated lines. The results also demonstrate than cells modified ton contain the herpes simplex virus-thymidin kinase (HSV-tk) gene under control of the EGR-1 promoter become sensitive to treatment with the anti-viral agent ganciclovir (GCV).whereas non irradiated cells and nontransfected cells were unaffected by this agent. The radioisotopes Tc-99m, I-131, and Ga-67-citrate were selected as Egr-1 activators for their potential to accumulate in tumors specifically. We studied Ga-67-citrate.a radioisotope employed in tumor scintigraphy, for its suit-ability for selective gene induction. The plasmid vector pEgr-1-Luc was transfected into AsPc-1 cells and then exposed to radioisotopes. Luciferase activity increased by 100-300 times over control. We also inserted the herpes simplex virus-thymidin kinase gene downstream of Egr-1 and teansfected this construct into AsPc-1 cells. Ca-67-citrate and ganciclovir were added to the cells and cell survival was assessed by MTT assay. The growth of AsPc-1 cells transfected with the pEgr-1-tk construct was suppressed 2 days after exposure of the cells to Ga-67-citrate. The results indicate that the EGR-1 promoter can be used to induce exogenous gene selectively in radiation fields and radioisotopes used for the treatment of malignant tumors.
|