apr-246 and Neoplasms

Dysfunction of the TP53 (p53) gene occurs in most if not all human malignancies. Two principal mechanisms are responsible for this dysfunction; mutation and downregulation of wild-type p53 mediated by MDM2/MDM4. Because of its almost universal inactivation in malignancy, p53 is a highly attractive target for the development of new anticancer drugs. Although multiple strategies have been investigated for targeting dysfunctional p53 for cancer treatment, only 2 of these have so far yielded compounds for testing in clinical trials. These strategies include the identification of compounds for reactivating the mutant form of p53 back to its wild-type form and compounds for inhibiting the interaction between wild-type p53 and MDM2/MDM4. Currently, multiple p53-MDM2/MDM4 antagonists are undergoing clinical trials, the most advanced being idasanutlin which is currently undergoing testing in a phase III clinical trial in patients with relapsed or refractory acute myeloid leukemia. Two mutant p53-reactivating compounds have progressed to clinical trials, i.e., APR-246 and COTI-2. Although promising data has emerged from the testing of both MDM2/MDM4 inhibitors and mutant p53 reactivating compounds in preclinical models, it is still unclear if these agents have clinical efficacy. However, should any of the compounds currently being evaluated in clinical trials be shown to have efficacy, it is likely to usher in a new era in cancer treatment, especially as p53 dysfunction is so prevalent in human cancers.

Topics: Aminoquinolines; Antineoplastic Agents; Cell Cycle Proteins; Humans; Neoplasms; para-Aminobenzoates; Protein Isoforms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-mdm2; Pyrrolidines; Quinuclidines; Thiosemicarbazones; Tumor Suppressor Protein p53

p53 is the most mutated protein in cancer and the reactivation of its inactive mutated form represents one possibility for antitumor therapy. Reactivation leads to the initiation of apoptosis followed by the suppression of the malignant phenotype. Prima-1 and its methylated form Prima-1Met (also called APR-246) are compounds capable of reactivating mutated p53. Both are low-molecular substances that have been tested in a number of tumor cell lines and tumors bearing mutated p53.. This article summarizes what is currently known about both compounds, describes the possibilities of their use in anti-tumor therapy, and outlines the results of currently undergoing clinical trials of APR-246.. The results show that the mechanism of action of both compounds is still not clear. The mechanism is only known clearly in the case of Prima-1, and APR-246 is only known to induce apoptosis. The specificity of both substances for mutated p53 differs considerably and depends mainly on the cell model employed and the type of mutation. In addition to p53 reactivation itself, these compounds likely influence other mechanisms that also affect cytotoxic activity. Key words: Prima-1Met - APR-246 - Prima-1 - reactivation of p53 - apoptosis NPU I - LO1413. This work was supported by the project MEYS - NPS I - LO1413. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Accepted: 16. 07. 2018.

Topics: Apoptosis; Aza Compounds; Bridged Bicyclo Compounds, Heterocyclic; Humans; Neoplasms; Quinuclidines; Tumor Suppressor Protein p53

TP53 (p53) is the single most frequently altered gene in human cancers, with mutations being present in approximately 50% of all invasive tumours. However, in some of the most difficult-to-treat cancers such as high-grade serous ovarian cancers, triple-negative breast cancers, oesophageal cancers, small-cell lung cancers and squamous cell lung cancers, p53 is mutated in at least 80% of samples. Clearly, therefore, mutant p53 protein is an important candidate target against which new anticancer treatments could be developed. Although traditionally regarded as undruggable, several compounds such as p53 reactivation and induction of massive apoptosis-1 (PRIMA-1), a methylated derivative and structural analogue of PRIMA-1, i.e. APR-246, 2-sulfonylpyrimidines such as PK11007, pyrazoles such as PK7088, zinc metallochaperone-1 (ZMC1), a third generation thiosemicarbazone developed by Critical Outcome Techonologies Inc. (COTI-2) as well as specific peptides have recently been reported to reactive mutant p53 protein by converting it to a form exhibiting wild-type properties. Consistent with the reactivation of mutant p53, these compounds have been shown to exhibit anticancer activity in preclinical models expressing mutant p53. To date, two of these compounds, i.e. APR-246 and COTI-2 have progressed to clinical trials. A phase I/IIa clinical trial with APR-246 reported no major adverse effect. Currently, APR-246 is undergoing a phase Ib/II trial in patients with advanced serous ovarian cancer, while COTI-2 is being evaluated in a phase I trial in patients with advanced gynaecological cancers. It remains to be shown however, whether any mutant p53 reactivating compound has efficacy for the treatment of human cancer.

Topics: Antineoplastic Agents; Cell Line, Tumor; Genes, p53; Genetic Therapy; Humans; Molecular Targeted Therapy; Mutation; Neoplasms; Quinuclidines; Tumor Suppressor Protein p53

Topics: Antineoplastic Agents; Disease-Free Survival; Female; Humans; Male; Molecular Targeted Therapy; Mutation; Neoplasms; Patient Safety; Quinuclidines; Risk Assessment; Sensitivity and Specificity; Signal Transduction; Survival Analysis; Treatment Outcome; Tumor Suppressor Protein p53

We conducted a phase I, multicenter, open-label, dose-finding, and expansion study to determine the safety and preliminary efficacy of eprenetapopt (APR-246) combined with pembrolizumab in patients with advanced/metastatic solid tumors (ClinicalTrials.gov NCT04383938).. For dose-finding, requirements were non-central nervous system primary solid tumor, intolerant to/progressed after ≥1 line of treatment, and eligible for pembrolizumab; for expansion: (i) gastric/gastroesophageal junction tumor, intolerant to/progressed after first-line treatment, and no prior anti-programmed cell death receptor-1 (PD-1)/programmed death-ligand 1 (PD-L1) therapy; (ii) bladder/urothelial tumor, intolerant to/progressed after first-line cisplatin-based chemotherapy, and no prior anti-PD-1/PD-L1 therapy; (iii) non-small-cell lung cancer (NSCLC) with previous anti-PD-1/PD-L1 therapy. Patients received eprenetapopt 4.5 g/day intravenously (IV) on days 1-4 with pembrolizumab 200 mg IV on day 3 in each 21-day cycle. Primary endpoints were dose-limiting toxicity (DLT), adverse events (AEs), and recommended phase II dose (RP2D) of eprenetapopt.. Forty patients were enrolled (median age 66 years; range 27-85) and 37 received eprenetapopt plus pembrolizumab. No DLTs were reported and the RP2D for eprenetapopt in combination was 4.5 g/day IV on days 1-4. The most common eprenetapopt-related AEs were dizziness (35.1%), nausea (32.4%), and vomiting (29.7%). AEs leading to eprenetapopt discontinuation occurred in 2/37 patients (5.4%). In efficacy-assessable patients (n = 29), one achieved complete response (urothelial cancer), two achieved partial responses (NSCLC, urothelial cancer), and six patients had stable disease.. The eprenetapopt plus pembrolizumab combination was well tolerated with an acceptable safety profile and showed clinical activity in patients with solid tumors.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Humans; Middle Aged; Neoplasms; Quinuclidines

p53 mutants contribute to the chronic inflammatory tumour microenvironment (TME). In this study, we address the mechanism of how p53 mutants lead to chronic inflammation in tumours and how to transform it to restore cancer immune surveillance.. Our analysis of RNA-seq data from The Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) project revealed that mutant p53 (mtp53) cancers correlated with chronic inflammation. We used cell-based assays and a mouse model to discover a novel gain of function of mtp53 and the effect of the mtp53 reactivating compound APR-246 on the anti-tumour immune response.. We found that tumour samples from patients with breast carcinoma carrying mtp53 showed elevated Interferon (IFN) signalling, Tumour Inflammation Signature (TIS) score and infiltration of CD8+ T cells compared to wild type p53 (wtp53) tumours. We showed that the expression of IFN and immune checkpoints were elevated in tumour cells in a mtp53-dependent manner, suggesting a novel gain of function. Restoration of wt function to mtp53 by APR-246 induced the expression of endogenous retroviruses, IFN signalling and repressed immune checkpoints. Moreover, APR-246 promoted CD4+ T cells infiltration and IFN signalling and prevented CD8+ T cells exhaustion within the TME in vivo.. Breast carcinomas with mtp53 displayed enhanced inflammation. APR-246 boosted the interferon response or represses immune checkpoints in p53 mutant tumour cells, and restores cancer immune surveillance in vivo.

Topics: Animals; Gain of Function Mutation; Inflammation; Interferons; Mice; Neoplasms; Tumor Microenvironment; Tumor Suppressor Protein p53

In response to genotoxic stress, the tumor suppressor p53 acts as a transcription factor by regulating the expression of genes critical for cancer prevention. Mutations in the gene encoding p53 are associated with cancer development. PRIMA-1 and eprenetapopt (APR-246/PRIMA-1

Topics: Antineoplastic Agents; Aza Compounds; Bridged Bicyclo Compounds, Heterocyclic; Crystallography, X-Ray; Humans; Loss of Function Mutation; Neoplasms; Protein Domains; Quinuclidines; Recombinant Proteins; Tumor Suppressor Protein p53

The tumor suppressor gene TP53 is the most frequently mutated gene in cancer. The compound APR-246 (PRIMA-1Met/Eprenetapopt) is converted to methylene quinuclidinone (MQ) that targets mutant p53 protein and perturbs cellular antioxidant balance. APR-246 is currently tested in a phase III clinical trial in myelodysplastic syndrome (MDS). By in vitro, ex vivo, and in vivo models, we show that combined treatment with APR-246 and inhibitors of efflux pump MRP1/ABCC1 results in synergistic tumor cell death, which is more pronounced in TP53 mutant cells. This is associated with altered cellular thiol status and increased intracellular glutathione-conjugated MQ (GS-MQ). Due to the reversibility of MQ conjugation, GS-MQ forms an intracellular drug reservoir that increases availability of MQ for targeting mutant p53. Our study shows that redox homeostasis is a critical determinant of the response to mutant p53-targeted cancer therapy.

Topics: Cell Death; Cell Line, Tumor; Humans; Mutation; Neoplasms; Pharmaceutical Preparations; Quinuclidines; Sulfhydryl Compounds; Tumor Suppressor Protein p53

Topics: Alkylation; Aminoquinolines; Antineoplastic Agents; Apoptosis; Clinical Trials as Topic; Ellipticines; Humans; Mutation; Neoplasms; Protein Binding; Protein Interaction Domains and Motifs; Pyrazoles; Pyrroles; Quinuclidines; Structure-Activity Relationship; Thiosemicarbazones; Tumor Suppressor Protein p53