Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0001486 (Adenovirus)
 3,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

p73 has been shown to transcriptionally activate genes positively responsive to wild-type p53. In order to undertake a comparative study of functions of p53 and p73 we have cloned the cDNA of p73 from MCF-7 cells. Adenovirus onco-protein E1A inhibits the transactivation by p73; a deletion mutant of E1A incapable of interacting with p300 and CREB-binding protein (CBP) fails to disrupt the transactivation. Furthermore, CBP increases the transactivation mediated by p73 suggesting that CBP may function as a co-activator and E1A inhibits p73-mediated transactivation by sequestering p300 or CBP. We show that p73 can transcriptionally inhibit a number of cellular and viral promoters. However, wild-type p53, p73 alpha and p73 beta differ in their ability to inhibit transcriptional activity of different promoters. While wild-type p53 inhibits the promoters of the human cytomegalovirus (CMV) immediate-early gene, the long terminal repeat of human immunodeficiency virus type 1 (HIV LTR), human cyclin A (cyc A) gene, and insulin-like growth factor receptor I (IGF-I-R), p73 alpha only inhibits the HIV LTR and cyc A promoters significantly; and p73 beta inhibits the CMV, HIV LTR and cyc A promoters. A mutant of p73 alpha having amino acid substitutions at positions 268 and 300 on the presumptive DNA-binding domain fails to transactivate the p21 promoter but represses the CMV and the HIV LTR promoter quite efficiently showing that the mechanisms of transactivation and repression by p73 are different. Interestingly, p73 alpha transactivates the IGF-I-R promoter, which is inhibited by wild-type p53; p73 beta has no significant effect on this promoter. This is a unique situation where p73 alpha differs from p73 beta as well as p53.
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PMID:Differential modulation of cellular and viral promoters by p73 and p53. 1117 10

The cancer stem cell hypothesis suggests that rare populations of tumor-initiating cells may be resistant to therapy, lead to tumor relapse and contribute to poor prognosis for cancer patients. We previously demonstrated the feasibility of p53 pathway restoration in p53-deficient tumor cell populations using small molecules including ellipticine or its derivatives. We now establish a single cell p53-regulated green fluorescent protein (EGFP)-reporter system in human DLD1 colon tumor cells expressing mutant p53 protein. We use these p53-EGFP reporter DLD1 cells to investigate the status of p53 transcriptional activity in putative colon cancer stem cell populations following exposure to p53 pathway-restoring drugs and/or classical chemotherapy. We demonstrate induction of p53-specific EGFP reporter fluorescence following overexpression of p53 family member p73 by an Adenovirus vector. We further show that p53-reporter activity is induced in DLD1 putative cancer stem cell side-populations analyzed by their Hoechst dye efflux properties following treatment with the p53 pathway restoring drug ellipticine. Combination of ellipticine with the cytotoxic agent 5-fluorouracil resulted in increased cytotoxicity as compared to either agent alone and this was associated with depletion of putative cancer stem cell populations as compared with 5-FU alone treatment. Our results support the feasibility of therapeutic targeting of mutant p53 in putative cancer stem cells as well as the potential to enhance cytotoxic chemotherapy.
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PMID:The combination of 5-fluorouracil plus p53 pathway restoration is associated with depletion of p53-deficient or mutant p53-expressing putative colon cancer stem cells. 1992 10