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Restoration of the tumor suppressor function of tumor-associated p53 mutants, including the Y220C substitution, has posed a significant challenge for therapeutic discovery. Here, we describe rezatapopt (PC14586), part of a series of compounds designed to reactivate the p53 Y220C mutant. These compounds restore p53 tumor suppressor function by correcting its conformation and enabling it to bind DNA and activate downstream target genes, thus inducing anti-proliferative changes in tumor cells. Our findings are supported by biochemical and structural analysis, in vitro and in vivo transcriptomics, and functional data, revealing the recovery of multiple aspects of the wild type p53 program. These compounds demonstrate potent anti-tumor activity in preclinical models as single agents and in combination with immunotherapy. Currently, rezatapopt is being evaluated in a registrational Phase 2 clinical trial for patients with advanced solid tumors harboring the TP53 Y220C mutation.

Cyclin D proteins are elevated in many cancer cells, and targeted deletion of cyclin D1 gene in the mammary tissues protects mice from breast cancer. Accordingly, there is an increasing awareness of this novel nonenzymatic target for cancer therapeutics. We have developed novel, nonalkylating styrylbenzylsulfones that induce cell death in wide variety of cancer cells without affecting the proliferation and survival of normal cells. The development of derivatized styrylbenzylsulfones followed logically from a tumor cell cytotoxicity screen performed in our laboratory that did not have an a priori target profile. Modifications of some of the precursor molecules led to lead optimization with regard to tumor cell cytotoxicity. In this report we describe the synthesis and structure-activity relationships of novel, nonalkylating (E)-styrylbenzylsulfones and the development of the novel anticancer agent sodium (E)-2-{2-methoxy-5-[(2',4',6'-trimethoxystyrylsulfonyl)methyl]phenylamino}acetate (ON 01910.Na), which is in phase III trials for myelodysplastic syndromes (MDS) associated with aberrant expression of cyclin D proteins.

A novel series of AKT inhibitors containing 2,3,5-trisubstituted pyridines with novel azaindazoles as hinge binding elements are described. Among these, the 4,7-diazaindazole compound 2c has improved drug-like properties and kinase selectivity than those of indazole 1, and displays greater than 80% inhibition of GSK3beta phosphorylation in a BT474 tumor xenograft model in mice., (Copyright 2009 Elsevier Ltd. All rights reserved.)

The synthesis and evaluation of tetrasubstituted aminopyridines, bearing novel azaindazole hinge binders, as potent AKT inhibitors are described. Compound 14c was identified as a potent AKT inhibitor that demonstrated reduced CYP450 inhibition and an improved developability profile compared to those of previously described trisubstituted pyridines. It also displayed dose-dependent inhibition of both phosphorylation of GSK3beta and tumor growth in a BT474 tumor xenograft model in mice., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Cell cycle progression is regulated by cyclins and cyclin-dependent kinases, which are formed at specific stages of the cell cycle and regulate the G1/S and G2/M phase transitions, employing a series of "checkpoints" governed by phosphorylation of their substrates. Tumor development is associated with the loss of these checkpoint controls, and this provides an approach for the development of therapeutic agents that can specifically target tumor cells. Here, we describe the synthesis and SAR of a novel group of cytotoxic molecules that selectively induce growth arrest of normal cells in the G1 phase while inducing a mitotic arrest of tumor cells resulting in selective killing of tumor cell populations with little or no effect on normal cell viability. The broad spectrum of antitumor activity in vitro and xenograft models, lack of in vivo toxicity, and drug resistance suggest potential for use of these agents in cancer therapy.

Imatinib, which is an inhibitor of the BCR-ABL tyrosine kinase, has been a remarkable success for the treatment of Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemias (CMLs). However, a significant proportion of patients chronically treated with imatinib develop resistance because of the acquisition of mutations in the kinase domain of BCR-ABL. Mutations occur at residues directly implicated in imatinib binding or, more commonly, at residues important for the ability of the kinase to adopt the specific closed (inactive) conformation to which imatinib binds. In our quest to develop new BCR-ABL inhibitors, we chose to target regions outside the ATP-binding site of this enzyme because these compounds offer the potential to be unaffected by mutations that make CML cells resistant to imatinib. Here we describe the activity of one compound, ON012380, that can specifically inhibit BCR-ABL and induce cell death of Ph+ CML cells at a concentration of <10 nM. Kinetic studies demonstrate that this compound is not ATP-competitive but is substrate-competitive and works synergistically with imatinib in wild-type BCR-ABL inhibition. More importantly, ON012380 was found to induce apoptosis of all of the known imatinib-resistant mutants at concentrations of <10 nM concentration in vitro and cause regression of leukemias induced by i.v. injection of 32Dcl3 cells expressing the imatinib-resistant BCR-ABL isoform T315I. Daily i.v. dosing for up to 3 weeks with a >100 mg/kg concentration of this agent is well tolerated in rodents, without any hematotoxicity.