Maitra Radhashree, Seetharam Raviraja, Tesfa Lydia, Augustine Titto A, Klampfer Lidija, Coffey Matthew C, Mariadason John M, Goel Sanjay
Department of Oncology, Montefiore Medical Center, Bronx, NY.
Oncotarget. 2014 May 15;5(9):2807-19. doi: 10.18632/oncotarget.1921.
Reovirus is a double stranded RNA virus, with an intrinsic preference for replication in KRAS mutant cells. As 45% of human colorectal cancers (CRC) harbor KRAS mutations, we sought to investigate its efficacy in KRAS mutant CRC cells, and examine its impact in combination with the topoisimerase-1 inhibitor, irinotecan. Reovirus efficacy was examined in the KRAS mutant HCT116, and the isogenic KRAS WT Hke3 cell line, and in the non-malignant rat intestinal epithelial cell line. Apoptosis was determined by flow cytometry and TUNEL staining. Combination treatment with reovirus and irintoecan was investigated in 15 CRC cell lines, including the HCT116 p21 isogenic cell lines. Reovirus preferentially induced apoptosis in KRAS mutant HCT116 cells compared to its isogenic KRAS WT derivative, and in KRAS mutant IEC cells. Reovirus showed a greater degree of caspase 3 activation with PARP 1 cleavage, and preferential inhibition of p21 protein expression in KRAS mutant cells. Reovirus synergistically induced growth inhibition when combined with irinotecan. This synergy was lost upon p21 gene knock out. Reovirus preferentially induces apoptosis in KRAS mutant colon cancer cells. Reovirus and irinotecan combination therapy is synergistic, p21 mediated, and represents a novel potential treatment for patients with CRC.
呼肠孤病毒是一种双链RNA病毒，在KRAS突变细胞中具有内在的复制偏好。由于45%的人类结直肠癌（CRC）存在KRAS突变，我们试图研究其在KRAS突变的CRC细胞中的疗效，并研究其与拓扑异构酶-1抑制剂伊立替康联合使用时的影响。在KRAS突变的HCT116、同基因的KRAS野生型Hke3细胞系以及非恶性大鼠肠上皮细胞系中检测呼肠孤病毒的疗效。通过流式细胞术和TUNEL染色确定细胞凋亡。在15种CRC细胞系中研究了呼肠孤病毒与伊立替康的联合治疗，包括HCT116 p21同基因细胞系。与同基因的KRAS野生型衍生物相比，呼肠孤病毒优先诱导KRAS突变的HCT116细胞以及KRAS突变的IEC细胞发生凋亡。呼肠孤病毒在PARP 1裂解时显示出更高程度的半胱天冬酶3激活，并优先抑制KRAS突变细胞中p21蛋白的表达。当与伊立替康联合使用时，呼肠孤病毒协同诱导生长抑制。在p21基因敲除后，这种协同作用消失。呼肠孤病毒优先诱导KRAS突变的结肠癌细胞发生凋亡。呼肠孤病毒与伊立替康联合治疗具有协同作用，由p21介导，是CRC患者一种新的潜在治疗方法。
