2-2-bis(hydroxymethyl)-1-azabicyclo(2-2-2-)octan-3-one and fludarabine

APR-246 belongs to a new generation of the compounds that restore normal p53 function in cells with mutated or wild type p53. The purpose of this study was to examine the effects of APR-246 alone and in combination with other drugs in acute myeloid leukemia (AML) cells.. Primary leukemic cells from patients with AML and AML cell lines were studied with respect to cytotoxic and apoptotic effects and mechanism of action of APR-246, alone and in combination with Ara-C, daunorubicin and fludarabine.. APR-246 showed dose-dependent cytotoxic and apoptotic effects in AML cell lines as well as in primary AML patient cells. Cells from patients with TP53 mutation and complex karyotype were more resistant to conventional drugs while these factors did not significantly affect the sensitivity to APR-246. APR-246 increased active caspase-3, upregulated p53 protein levels, and increased the bax/bcl-2 ratio independently of TP53 mutational status in patient cells sensitive to APR-246. AML cells with high p14(ARF) expression were significantly more sensitive to APR-246. APR-246 induced significant synergistic effects in combination with conventional chemotherapeutic agents. Pre-incubation with APR-246 induced more synergistic effects compared to other schedules. In patient cells, pronounced synergism was found when combining APR-246 with danuorubicin.. We conclude that APR-246 is effective in AML cells irrespectively of TP53 mutational status and that it has promising properties for combination studies in AML.

Topics: Antineoplastic Agents; Aza Compounds; Base Sequence; bcl-2-Associated X Protein; Bridged Bicyclo Compounds, Heterocyclic; Cytarabine; Daunorubicin; DNA Primers; Drug Resistance, Neoplasm; Drug Synergism; Female; Gene Expression; Genes, p53; Humans; Karyotyping; Leukemia, Myeloid, Acute; Male; Mutation; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Tumor Suppressor Protein p14ARF; Vidarabine

The tumour suppressor gene p53 is the most commonly mutated gene in solid tumours. Although less common in haematological malignancies, 10-15% of B-cell chronic lymphocytic leukaemia (B-CLL) cases carry a p53 mutation. Recently, the compound P53-dependent reactivation and induction of massive apoptosis (PRIMA-1) has been shown to induce cytotoxic effects and apoptosis in human tumour cells by restoration of the transcriptional activity of mutated p53. This is believed to be mediated by a change in the conformation of mutated p53 protein, restoring DNA binding and activation of p53 target genes. We studied the effects of PRIMA-1 and commonly used anti-leukaemic drugs on B-CLL cells from 14 patients with and without hemizygous p53 deletion. Cells obtained from peripheral blood or bone marrow were exposed to PRIMA-1 and fludarabine alone or in combination. PRIMA-1 showed cytotoxic effects on B-CLL cells from samples with and without hemizygous p53 deletion. Furthermore, conventional B-CLL drugs were less effective in cell samples with hemizygous p53 deletion and the response depended on the size of the p53 deleted clone. Finally, we found evidence for synergistic and additive effects of PRIMA-1 in combination with fludarabine.

Topics: Antineoplastic Agents; Apoptosis; Aza Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Drug Synergism; Gene Deletion; Genes, p53; Humans; In Situ Hybridization, Fluorescence; Leukemia, Lymphocytic, Chronic, B-Cell; Vidarabine