Department of Pathology, Cancer Research Institute, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, South Korea.
Mol Cancer. 2011 Aug 16;10:98. doi: 10.1186/1476-4598-10-98.
Gemcitabine is used to treat several cancers including lung cancer. However, tumor cells often escape gemcitabine-induced cell death via various mechanisms, which include modulating bcl-2 family members and NF-κB activation. We previously reported that the C-terminal region of Bfl-1 fused with GFP (BC) is sufficient to induce apoptosis in 293T cells. In the present study, we investigated the anti-tumor effect of combined BC gene therapy and gemcitabine chemotherapy in vitro and in vivo using non-small cell lung cancer cell lines and a xenograft model. Cell lines were resistant to low dose gemcitabine (4-40 ng/ml), which induced NF-κB activation and concomitant up-regulation of Bfl-1 (an NF-κB-regulated anti-apoptotic protein). BC induced the apoptosis of A549 and H157 cells with caspase-3 activation. Furthermore, co-treatment with BC and low dose gemcitabine synergistically and efficiently induced mitochondria-mediated apoptosis in these cells. When administered alone or with low dose gemcitabine, BC suppressed NF-κB activity, inhibited the nuclear translocation of p65/relA, and down-regulated Bfl-1 expression. Furthermore, direct suppression of Bfl-1 by RNA interference sensitized cells to gemcitabine-induced cell death, suggesting that Bfl-1 importantly regulates lung cancer cell sensitivity to gemcitabine. BC and gemcitabine co-treatment also showed a strong anti-tumor effect in a nude mouse/A549 xenograft model. These results suggest that lung cancer cells become resistant to gemcitabine via NF-κB activation and the subsequent overexpression of Bfl-1, and that BC, which has both pro-apoptotic and NF-κB inhibitory effects, could be harnessed as a gene therapy to complement gemcitabine chemotherapy in non-small cell lung cancer.
吉西他滨用于治疗多种癌症，包括肺癌。然而，肿瘤细胞通常通过多种机制逃避吉西他滨诱导的细胞死亡，包括调节 bcl-2 家族成员和 NF-κB 激活。我们之前报道过 Bfl-1 的 C 端与 GFP 融合（BC）足以在 293T 细胞中诱导凋亡。在本研究中，我们使用非小细胞肺癌细胞系和异种移植模型，在体外和体内研究了联合 BC 基因治疗和吉西他滨化疗对肿瘤的治疗作用。细胞系对低剂量吉西他滨（4-40ng/ml）有耐药性，该药物诱导 NF-κB 激活并伴随 Bfl-1（NF-κB 调节的抗凋亡蛋白）上调。BC 诱导 A549 和 H157 细胞凋亡，伴有 caspase-3 激活。此外，BC 与低剂量吉西他滨联合治疗可协同有效地诱导这些细胞中线粒体介导的凋亡。BC 单独或与低剂量吉西他滨联合使用时，均可抑制 NF-κB 活性，抑制 p65/relA 的核转位，并下调 Bfl-1 的表达。此外，RNA 干扰直接抑制 Bfl-1 可使细胞对吉西他滨诱导的细胞死亡敏感，表明 Bfl-1 对肺癌细胞对吉西他滨的敏感性具有重要调节作用。BC 和吉西他滨联合治疗在裸鼠/A549 异种移植模型中也表现出很强的抗肿瘤作用。这些结果表明，肺癌细胞通过 NF-κB 激活和随后 Bfl-1 的过度表达对吉西他滨产生耐药性，而具有促凋亡和 NF-κB 抑制作用的 BC 可被用作基因治疗，与吉西他滨化疗互补，用于非小细胞肺癌。
