These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: High levels of constitutive WAF1/Cip1 protein are associated with chemoresistance in acute myelogenous leukemia.
    Author: Zhang W, Kornblau SM, Kobayashi T, Gambel A, Claxton D, Deisseroth AB.
    Journal: Clin Cancer Res; 1995 Sep; 1(9):1051-7. PubMed ID: 9816079.
    Abstract:
    The WAF1/Cip1 gene product is an important regulator at the G1 checkpoint in the cell cycle. WAF1/Cip1 expression can be activated through p53-dependent and p53-independent pathways. The WAF1/Cip1 protein binds to cyclin-dependent kinase complexes and inhibits the kinase activity that is required for cell cycle progression. In this preliminary study, we analyzed with Western blot assays the steady-state levels of the WAF1/Cip1 protein in the leukemia cells of 100 untreated acute myelogenous leukemia (AML) patients. Normal bone marrow cells from six donors were used as a control. The results of these analyses showed that the levels of the WAF1/Cip1 protein were very low in normal marrow cells and in the leukemia cells of 83 AML patients. High levels of WAF1/Cip1 were detected in 17 patients; these patients with high WAF1/Cip1 levels were significantly less likely to achieve complete remission (41% versus 69%, P = 0.03) and were four times as likely to be resistant to therapy (47% versus 12%, P = 0.003) as patients with very low levels of WAF1/Cip1. Median survival was 38 weeks for patients having very low expression levels versus 11 weeks for patients having high expression levels (P = 0.04). The WAF1/Cip1 level was an independent predictor for response but not survival in a stepwise multivariate regression analysis. Southern blotting analyses did not detect deletion of the WAF1/Cip1 gene in the 12 negative WAF1/Cip1 AML samples tested. Also, the level of WAF1/Cip1 protein expression was not correlated with overexpression of cyclin D1, cyclin E, proliferating cell nuclear antigen, cyclin-dependent kinase 4, or p53 in the leukemia cells. However, the levels of cyclin D1, cyclin E, and cyclin-dependent kinase 4 were elevated in most of the AML samples compared with that in normal marrow. We hypothesize that high-level constitutively expressed WAF1/Cip1 in tumor cells may result in an indolent state that is refractory to chemotherapy drugs. We conclude that the WAF1/Cip1 expression level may be an important prognostic factor for response to therapy and survival in AML patients.
    [Abstract] [Full Text] [Related] [New Search]