Kaliberova Lyudmila N, Della Manna Debbie L, Krendelchtchikova Valentina, Black Margaret E, Buchsbaum Donald J, Kaliberov Sergey A
Department of Radiation Oncology, University of Alabama at Birmingham, 1530 3rd Avenue South, WTI 674, Birmingham, AL 35294-6832, USA.
Mol Cancer Ther. 2008 Sep;7(9):2845-54. doi: 10.1158/1535-7163.MCT-08-0347.
The combination of molecular chemotherapy with radiation therapy has the potential to become a powerful approach for treatment of pancreatic cancer. We have developed an adenoviral vector (AdbCD-D314A) encoding a mutant bacterial cytosine deaminase (bCD) gene, which converts the prodrug 5-fluorocytosine (5-FC) into the active drug 5-fluorouracil. The aim of this study was to investigate AdbCD-D314A/5-FC-mediated cytotoxicity in vitro and therapeutic efficacy in vivo alone and in combination with radiation against human pancreatic cancer cells and xenografts. AdbCD-D314A/5-FC-mediated cytotoxicity alone and in combination with radiation was analyzed using crystal violet inclusion and clonogenic survival assays. CD enzyme activity was determined by measuring conversion of [3H]5-FC to [3H]5-fluorouracil after adenoviral infection of pancreatic cancer cells in vitro and pancreatic tumor xenografts by TLC. S.c. pancreatic tumor xenografts were used to evaluate the therapeutic efficacy of AdbCD-D314A/5-FC molecular chemotherapy in combination with radiation therapy. AdbCD-D314A infection resulted in increased 5-FC-mediated pancreatic cancer cell killing that correlated with significantly enhanced CD enzyme activity compared with AdbCDwt encoding wild-type of bCD. Animal studies showed significant inhibition of growth of human pancreatic tumors treated with AdbCD-D314A/5-FC in comparison with AdbCDwt/5-FC. Also, a significantly greater inhibition of growth of Panc2.03 and MIA PaCA-2 tumor xenografts was produced by the combination of AdbCD-D314A/5-FC with radiation compared with either agent alone. The results indicate that the combination of AdbCD-D314A/5-FC molecular chemotherapy with radiation therapy significantly enhanced cytotoxicity of pancreatic cancer cells in vitro and increased therapeutic efficacy against human pancreatic tumor xenografts.
分子化疗与放射治疗相结合有可能成为治疗胰腺癌的有效方法。我们构建了一种腺病毒载体（AdbCD-D314A），其编码一种突变型细菌胞嘧啶脱氨酶（bCD）基因，该基因可将前药5-氟胞嘧啶（5-FC）转化为活性药物5-氟尿嘧啶。本研究旨在探讨AdbCD-D314A/5-FC单独及与放疗联合应用时对人胰腺癌细胞及异种移植瘤的体外细胞毒性和体内治疗效果。采用结晶紫包被法和克隆形成存活试验分析AdbCD-D314A/5-FC单独及与放疗联合应用时的细胞毒性。通过薄层色谱法在体外对胰腺癌细胞和胰腺肿瘤异种移植瘤进行腺病毒感染后，通过测量[3H]5-FC向[3H]5-氟尿嘧啶的转化来测定CD酶活性。皮下接种的胰腺肿瘤异种移植瘤用于评估AdbCD-D314A/5-FC分子化疗联合放射治疗的疗效。与编码野生型bCD的AdbCDwt相比，AdbCD-D314A感染导致5-FC介导的胰腺癌细胞杀伤增加，且与显著增强的CD酶活性相关。动物研究表明，与AdbCDwt/5-FC相比，AdbCD-D314A/5-FC治疗的人胰腺肿瘤生长受到显著抑制。此外，与单独使用任何一种药物相比，AdbCD-D314A/5-FC与放疗联合应用对Panc2.03和MIA PaCA-2肿瘤异种移植瘤的生长抑制作用明显更强。结果表明，AdbCD-D314A/5-FC分子化疗与放射治疗相结合可显著增强体外胰腺癌细胞的细胞毒性，并提高对人胰腺肿瘤异种移植瘤的治疗效果。
