Yacoub Adly, Hamed Hossein, Emdad Luni, Dos Santos Wagner, Gupta Pankaj, Broaddus William C, Ramakrishnan Viswanathan, Sarkar Devanand, Shah Khalid, Curiel David T, Grant Steven, Fisher Paul B, Dent Paul
Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia 23298-0035, USA.
Cancer Biol Ther. 2008 Jun;7(6):917-33. doi: 10.4161/cbt.7.6.5928. Epub 2008 Mar 19.
Melanoma differentiation associated gene-7/interleukin 24 (mda-7/IL-24) is a cytokine displaying selective apoptosis-inducing activity in tumors, including glioblastoma (GBM), without damaging normal cells. The present studies focused on defining whether an adenovirus expressing MDA-7/IL-24, Ad.mda-7, infused into pre-formed invasive primary human GBM tumors growing in athymic mouse brains altered tumor cell growth and animal survival, and whether Ad.mda-7 radiosensitized GBM cells and enhanced the survival benefit of irradiation. Ad.mda-7 directly radiosensitized glioma cells in vitro in a JNK1-3- and caspase 9-dependent fashion and demonstrated bystander-effect killing and radiosensitization of GBM cells when primary human astrocytes were infected with Ad.mda-7. Infusion of Ad.mda-7 into pre-formed glioma tumors caused a rapid decrease in proliferation and blood vessel density and an increase in cell killing. Irradiation of Ad.mda-7 infected tumors enhanced cell death. Cell killing correlated with pro-caspase 3 cleavage, enhanced phosphorylation of JNK1-3 and reduced phosphorylation of ERK1/2. Ad.mda-7 enhanced the survival of animals implanted with GBM6 and GBM12 tumors, and significantly increased the survival benefit of irradiation in animals bearing GBM12 tumors. Ad.mda-7 toxicity was evident against CD133+ and CD133- GBM cells; upon tumor re-growth approximately 70-100 days after virus infusion, the relative CD133+ level within the tumor was profoundly reduced with lower Ki67 reactivity and increased beta-galactosidase staining. Infusion of Ad.mda-7 into an immune competent rat brain did not cause normal tissue toxicity 1-4 weeks after infusion using T1 and T2 weighted MRI and H&E staining. Our data demonstrate that Ad.mda-7 prolongs the survival of animals bearing GBM tumors and does so through multiple mechanisms including direct tumor cell killing and selection for surviving cells that are more differentiated and potentially displaying a putatively senescent phenotype.
黑色素瘤分化相关基因-7/白细胞介素24(mda-7/IL-24)是一种细胞因子,在包括胶质母细胞瘤(GBM)在内的肿瘤中具有选择性诱导凋亡的活性,且不损伤正常细胞。目前的研究集中于确定将表达MDA-7/IL-24的腺病毒Ad.mda-7注入无胸腺小鼠脑内预先形成的侵袭性原发性人GBM肿瘤中是否会改变肿瘤细胞生长和动物存活,以及Ad.mda-7是否会使GBM细胞对辐射敏感并增强放疗的生存获益。Ad.mda-7在体外以JNK1-3和半胱天冬酶9依赖性方式直接使胶质瘤细胞对辐射敏感,并且当原代人星形胶质细胞被Ad.mda-7感染时,显示出对GBM细胞的旁观者效应杀伤和辐射增敏作用。将Ad.mda-7注入预先形成的胶质瘤肿瘤中导致增殖和血管密度迅速降低以及细胞杀伤增加。对Ad.mda-7感染的肿瘤进行放疗可增强细胞死亡。细胞杀伤与前半胱天冬酶3的切割、JNK1-3磷酸化增强以及ERK1/2磷酸化降低相关。Ad.mda-7提高了植入GBM6和GBM12肿瘤动物的存活率,并显著增加了携带GBM12肿瘤动物放疗的生存获益。Ad.mda-7对CD133+和CD133- GBM细胞具有明显毒性;在病毒注入后约70 - 100天肿瘤重新生长时,肿瘤内相对CD133+水平显著降低,Ki67反应性降低,β-半乳糖苷酶染色增加。使用T1和T2加权MRI以及苏木精-伊红染色,在免疫功能正常的大鼠脑内注入Ad.mda-7后1 - 4周未引起正常组织毒性。我们的数据表明,Ad.mda-7可延长携带GBM肿瘤动物的存活时间,并且是通过多种机制实现的,包括直接杀伤肿瘤细胞以及选择更具分化性且可能呈现假定衰老表型的存活细胞。