Combination therapy of malignant glioma cells with 2-5A-antisense telomerase RNA and recombinant adenovirus p53.
Malignant gliomas of astrocytic origin have commonly expressed several features such as alterations in the tumor-suppressor gene p53 or p16 or the acquisition of telomerase activity, which are distinctive from astrocytes. Therefore, restoration of the tumor-suppressor gene or telomerase inhibition is expected to provide a cure for malignant gliomas. We have recently demonstrated that the treatment with a 19-mer antisense oligonucleotide against human telomerase RNA linked to a 2',5'-oligoadenylate (2-5A-anti-hTR) inhibited the growth of malignant glioma cells. From a therapeutic point of view, it is very important to investigate the antitumor efficacy of 2-5A-anti-hTR combined with the restoration of p53 or p16 gene. In this study, we evaluated the antitumor effect of 2-5A-anti-hTR in combination with recombinant adenoviruses bearing p53, its associated p21WAF1/CIP1, or p16CDKN2 gene (Ad5CMV-p53, Ad5CMV-p21, or Ad5CMV-p16) against malignant glioma cells in vitro and in vivo. Five malignant glioma cell lines expressing the mutant p53 gene (A172, GB-1, T98G, U251-MG and U373-MG) were more sensitive to the combination of 2-5A-anti-hTR and Ad5CMV-p53 than to other combinations. The additive effect of the combination therapy was due to induction of caspase-dependent apoptosis and cell growth arrest. Furthermore, the 2-5A-anti-hTR treatment when combined with Ad5CMV-p53 showed greater efficacy against subcutaneous U251-MG tumors in nude mice. In contrast, U87-MG cells expressing the wild-type p53 gene were insensitive to Ad5CMV-p53, although the treatment with 2-5A-anti-hTR was significantly effective. These results indicate that combining 2-5A-anti-hTR with Ad5CMV-p53 has the most therapeutic potential for malignant gliomas with mutant p53. For tumors exhibiting wild-type p53, it may be useful to treat with 2-5A-anti-hTR. Gene Therapy (2000) 7, 2071-2079.
The Center for Surgery Research, The Cleveland Clinic Foundation, Cleveland, OH, USA.
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Kondo
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Koga
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Chung
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D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D016543:Central Nervous System Neoplasms / Q000473:pathology / Q000628:therapy*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics; D005434:Flow Cytometry; D019942:Genes, p16; D016158:Genes, p53; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage; D005910:Glioma / Q000473:pathology / Q000628:therapy*; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000628:therapy; D016372:RNA, Antisense / Q000008:administration & dosage*; D019098:Telomerase / Q000235:genetics*; D014407:Tumor Cells, Cultured
C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016372:RNA, Antisense; D019098:Telomerase