Abstract
1443
Objectives: Cotransfection of multi-drug resistance (MDR) reversing siRNA and other therapeutic gene might be used to treat cancers with MDR expression. MDR expressing cancer can be effectively treated by selective short hairpin RNA (shRNA) for mdr1 gene and therapeutic sodium iodide symporter (NIS) gene transfection. In this study, we constructed vector expressing shRNA and NIS and transfected the vector to colon cancer cell line and investigated a change of 99mTc-MIBI and I-125 uptakes in the transfected cell. Methods: We produced adenovirus for each shMDR (Ad-shMDR) and NIS (Ad-NIS) gene expression. Ad-shMDR and Ad-NIS were cotransfected into HCT15 cell. HCT15 cell lines were infected with 300 MOI of Ad-shMDR with or without 10 MOI of Ad-NIS. In the transfected cell degree of mdr1 mRNA expression was measured by RT-PCR and P-gp expression was measured by western blot analysis. Forty-eight hours after infection, inhibition of P-gp function by shMDR was analyzed a change of 99mTc-MIBI uptake, and functional activity of induced NIS expression was assessed a change of I-125 uptake. Doxorubicin cytotoxicity also measured in Ad-shMDR transfected or non-transfected cell lines. Results: Ad-shMDR and Ad-NIS cotransfected colon cancer cell revealed down regulation of mdr1 mRNA and P-gp compared to those of non-transfected cell. After infection of 300 MOI of ad-shMDR with or without 10 MOI of Ad-NIS, uptake of 99mTc-MIBI increased up to ~1.5-fold than non-infected cells. The 10 MOI of Ad-NIS infected HCT15 cells showed approximately 25-fold higher I-125 uptake compared to non-infected cell. Ad-shMDR and Ad-NIS cotransfected HCT15 cell showed enhanced cytotoxicity by doxorubicin compared to that of non-infected cells. Conclusions: Suppression of mdr1 gene expression, retention of 99mTc-MIBI and enhanced doxorubicin cytotoxicity can be achieved by shMDR transfection in MDR expressing cancer and iodine uptake can be increased by NIS gene transfection. Dual therapy with doxorubicin and radioiodide followed by cotransfected with shMDR and NIS gene can be effectively used in MDR expressing cancer cell.
- Society of Nuclear Medicine, Inc.