p21WAF1/CIP1 is more effective than p53 in growth suppression of mouse renal carcinoma cell line Renca in vitro and in vivo.
OBJECTIVE
Although there are many controversial reports about the effect of p53 and p21(WAF1/CIP1) overexpression in different human tumor cells, the p53 gene is shown to be a more effective candidate for cancer gene therapy because of its more pronounced ability to induce apoptosis. In the present study, we present the effect of p53 and p21(WAF1/CIP1) overexpression on mouse renal carcinoma cells in vitro and in vivo.


METHODS
p53 and p21(WAF1/CIP1) genes were introduced into Renca cells using adenoviral vectors (Ad5CMV-p53 and Ad5CMV-p21). The induction of apoptosis was measured using Annexin V assay and DNA fragmentation analysis. The expression of proteins was examined using immunocytochemistry and Western blot methods. The ability of adenoviral vectors to inhibit tumorigenicity of Renca cells, as well as the growth of pre-established tumors was measured.


RESULTS
In vitro growth assays revealed higher growth suppression after Ad5CMV-p21 infection. Although both vectors induced apoptosis, Ad5CMV-p53 was slightly more efficient. In vivo studies in Balb/c mice, demonstrated that tumorigenicity was completely suppressed by Ad5CMV-p21. Besides this, Ad5CMV-p21 significantly inhibited the growth of established tumors, while Ad5CMV-p53 did not.


CONCLUSIONS
These data suggest that p21(WAF1/CIP1) is a more potent growth suppressor than p53 of mouse tumor cells Renca. The divergent responses of tumor cells to p21(WAF1/CIP1) overexpression could be due to various networks that differ between species.
Kralj
Marijeta
M
Division of Molecular Medicine, Rudjer Bosković Institute, Bijenicka c. 54, P.O.Box 180, 10002, Zagreb, Croatia. mhorvat@rudjer.irb.hr
Pavelić
Jasminka
J
D000256:Adenoviridae; D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002292:Carcinoma, Renal Cell / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005822:Genetic Vectors; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007680:Kidney Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D051379:Mice; D013997:Time Factors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000494:pharmacology; D015854:Up-Regulation
D017304:Annexin A5; D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D016159:Tumor Suppressor Protein p53