apr-246 and Bone-Neoplasms

Though p53 mutations are rare in ES, there is a strong indication that p53 mutant tumours form a particularly bad prognostic group. As such, novel treatment strategies are warranted that would specifically target and eradicate tumour cells containing mutant p53 in this subset of ES patients.. PRIMA-1(Met), also known as APR-246, is a small organic molecule that has been shown to restore tumour-suppressor function primarily to mutant p53 and also to induce cell death in various cancer types. In this study, we interrogated the ability of APR-246 to induce apoptosis and inhibit tumour growth in ES cells with different p53 mutations.. APR-246 variably induced apoptosis, associated with Noxa, Puma or p21(WAF1) upregulation, in both mutant and wild-type p53 harbouring cells. The apoptosis-inducing capability of APR-246 was markedly reduced in ES cell lines transfected with p53 siRNA. Three ES cell lines established from the same patient at different stages of the disease and two cell lines of different patients with identical p53 mutations all exhibited different sensitivities to APR-246, indicating cellular context dependency. Comparative transcriptome analysis on the three cell lines established from the same patient identified differential expression levels of several TP53 and apoptosis-associated genes such as APOL6, PENK, PCDH7 and MST4 in the APR-246-sensitive cell line relative to the less APR-246-sensitive cell lines.. This is the first study reporting the biological response of Ewing sarcoma cells to APR-246 exposure and shows gross variability in responses. Our study also proposes candidate genes whose expression might be associated with ES cells' sensitivity to APR-246. With APR-246 currently in early-phase clinical trials, our findings call for caution in considering it as a potential adjuvant to conventional ES-specific chemotherapeutics.

Topics: Antineoplastic Agents; Apoptosis; Bone Neoplasms; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Microarray Analysis; Mutation; Quinuclidines; RNA, Small Interfering; Sarcoma, Ewing; Transcriptome; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Mutant p53-carrying tumors are often more resistant to chemotherapeutical drugs. We demonstrate here that the mutant p53-reactivating compound PRIMA-1(MET) acts synergistically with several chemotherapeutic drugs to inhibit tumor cell growth. Combined treatment with cisplatin and PRIMA-1(MET) resulted in a synergistic induction of tumor cell apoptosis and inhibition of human tumor xenograft growth in vivo in SCID mice. The induction of mutant p53 levels by chemotherapeutic drugs is likely to increase the sensitivity of tumor cells to PRIMA-1(MET). Thus, the combination of PRIMA-1(MET) with currently used chemotherapeutic drugs may represent a novel and more efficient therapeutic strategy for treatment of mutant p53-carrying tumors.

Topics: Adenocarcinoma; Animals; Apoptosis; Aza Compounds; Bone Neoplasms; Bridged Bicyclo Compounds, Heterocyclic; Carcinoma, Non-Small-Cell Lung; Cisplatin; Drug Interactions; Drug Resistance, Neoplasm; Genes, p53; Humans; Lung Neoplasms; Mice; Mice, SCID; Mutation; Osteosarcoma; Quinuclidines; Transplantation, Heterologous; Tumor Cells, Cultured