[The effect of p53 gene on p-glycoprotein expression and chemotherapeutic cytotoxicity of hepatocellular carcinoma].
OBJECTIVE
To test the hypothesis that wild-type p53 regulates the expression of p-glycoprotein.


METHODS
Hep3B cells which lack the expression of both p53 and retinoblastoma tumor suppressor genes because of deletions, were transfected with a wild-type (wt) p53 cDNA and control vector by a liposome method.


RESULTS
After G418 selection, stable wt-p53 transformants and control vector transformants (pNeo) were obtained. Northern and Western blot analysis determined the expression of p53 mRNA and protein in wt-p53 transformants, respectively. In wt-p53 transformants, induction of transcriptionally active p53 was confirmed by the increase of P21(waf1/cip1) protein. Levels of P-gp reduced in the cells expressing wild-type p53 were linked to wt-p53 activity. Cytotoxicity assays revealed that the wt-p53 transfectants were more sensitive to doxorubicin and mitomycin compared with the pNeo transformants. Flow cytometry showed that the accumulation of doxorubicin in wt-p53 transfectants was as 13 times as that of the pNeo transformants.


CONCLUSIONS
Restoration of wt-p53 activity in Hep3B leads to sensitiveness to chemotherapeutic agents because of the decrease of p-glycoprotein expression.
Han
Y
Y
Department of Hepatobiliary Surgery, First Affiliated Hospital of Sun Yat-sen University of Medical Sciences. Guangzhou 510080, China.
Liang
L
L
Huang
J
J
Ming
W
W
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D004347:Drug Interactions; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000494:pharmacology*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin