Adenovirus-mediated expression of PML suppresses growth and tumorigenicity of prostate cancer cells.
Our previous studies demonstrated that the promyelocytic leukemia gene, PML, encodes a growth and transformation suppressor. Overexpression of PML inhibits cancer cell growth in vitro and in vivo. In this study, we further explored the possibility of applying PML as a potential agent for developing prostate cancer gene therapy using an adenovirus delivery system. We have constructed and produced the recombinant PML-adenovirus, Ad-PML, in which the full-length PML cDNA is driven by the strong cytomegalovirus promoter. In LNCaP, DU145, and PC-3 prostate cancer cell lines, an infection efficiency of 90% can be achieved at a concentration of 2, 10, and 100 multiplicity of infection (MOI), respectively. Western blotting and immunofluorescence staining demonstrated that the AD-PML-infected cells expressed a high level of PML protein. The protein expression peaked at days 3-4 postinfection, and a detectable level of PML was found at day 18 after viral infection. To test the effect of Ad-PML on the growth of prostate cancer cells, the DU145 and LNCaP cells were infected with 10 and 2 MOI of Ad-PML. We found that the growth rate of the Ad-PML-infected DU145 and LNCaP cells were significantly inhibited. A tumorigenicity test in nude mice showed that the Ad-PML-treated DU145 cells failed to form tumors. Most importantly, direct injection of Ad-PML into DU145-induced tumors was able to repress tumor growth in nude mice by 64%. Taken together, these data indicate that PML is a tumor growth suppressor in prostate cancer and that Ad-PML may be a potential candidate for human prostate cancer therapy.
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Division of Laboratory Medicine, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
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D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002455:Cell Division / Q000502:physiology; D005455:Fluorescent Antibody Technique; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C513293:Pml protein, mouse; D000071156:Promyelocytic Leukemia Protein; D011994:Recombinant Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human