Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have designed in vitro assays to investigate the possible association between apoptosis and chemotherapeutic sensitivity in acute myeloid leukemias (AMLs). Consistent low levels of spontaneous apoptosis were observed in myeloid cells from normal bone marrow samples, while untreated cells collected from 56 de novo AML patients showed variable apoptosis. Control myeloid cells showed increased apoptosis after in vitro treatments with daunomycin (DNR), cytosine arabinoside (ARA-C), or gamma irradiation (RAD). Most AML samples showed less treatment-associated apoptosis, suggesting that apoptosis responses to therapeutic agents may be frequently attenuated in AML. Certain cytogenetic abnormalities common in AML may affect apoptosis, as acute promyelocytic leukemia (APL) samples with t(15;17) karyotypes showed consistently low levels of spontaneous and treatment-associated apoptosis. Apoptosis assays may provide unique functional subtyping of AMLs, as other common cytogenetic subsets showed variable apoptosis. Altered function of two well-characterized regulators of apoptosis, BCL-2 and p53, was not entirely responsible for this variability. A genomic p53 mutation was found in only one AML sample. All samples that demonstrated the highest BCL-2-positive cell fractions showed low apoptosis, but reduced apoptosis was seen in both the presence and absence of BCL-2 overexpression. Finally, data from matched diagnosis and relapse sample pairs suggest that neither further reduced apoptosis nor additional BCL-2 overexpression is necessarily associated with disease progression.
 ...
PMID:Measurement of spontaneous and therapeutic agent-induced apoptosis with BCL-2 protein expression in acute myeloid leukemia. 897 98

Biology of HIV-1 associated neoplasias is modulated by viral and host factors. In addition the development of tumors and their response to therapy may be further influenced by long-term treatment of HIV-1 patients with nucleoside analogs such as AZT (3'-azido-3'deoxythymidine), ddI (2',3'-dideoxyinosine), ddC (2',3'-dideoxycytidine), d4T (2',3'-didehydro-2'3'-dideoxythymidine), and 3TC [(-)-beta-L-2',3'-dideoxy-3'-thiacytidine] alone or in combination. As these compounds can trigger mechanisms involved in chemoresistance, we tested whether prolonged in vitro treatment of H9 cells (T-cell lymphoma) with AZT alters sensitivity of lymphoma cells to antitumor agents used for AIDS-associated malignancies. H9 cells grown for more than two years in medium containing 250 microM AZT developed resistance to the toxic effects of AZT while retaining sensitivity for other nucleoside analogs including ddC or cytosine arabinoside (ARA-C). These cells designated H9rAZT250 were 2 to 10-fold less sensitive to the toxic effects of antitumor agents, including cisplatin (CDDP), vincristine (VCR), doxorubicin (DOX) and etoposide (VP-16), when compared with parental H9 cells. The resistance of H9rAZT250 cells to antitumor agents was associated with inhibition of apoptosis as demonstrated by ultrastructural investigations and DNA-fragmentation assay (ELISA). The expression of the antiapoptotic gene bcl-2 was increased in H9rAZT250 cells while expression of other genes involved in the regulation of apoptosis such as c-myc, p53 and Fas was not changed. These results demonstrate that prolonged in vitro treatment of H9 lymphoma cells with AZT results in the development of resistance to antitumor agents in association with inhibition of apoptosis and increased expression of bcl-2. Therefore AZT long-term treatment of some HIV-1 patients with malignancies may have affected behavior of tumor cells including response to therapy.
 ...
PMID:Azidothymidine resistance of H9 human T-cell lymphoma cells is associated with decreased sensitivity to antitumor agents and inhibition of apoptosis. 985 Jul 37