sf-1126 and Multiple-Myeloma

Multiple reports point to an important role for the phosphoinositide-3 kinase (PI3K) and AKT signaling pathways in tumor survival and chemoresistance in multiple myeloma (MM). The goals of our study were: (1) to generate the preclinical results necessary to justify a Phase I clinical trial of SF1126 in hematopoietic malignancies including MM and (2) to begin combining pan-PI3K inhibitors with other agents to augment antitumor activity of this class of agent in preparation for combination therapy in Phase I/II trials.. We determined the in vitro activity of SF1126 with 16 human MM cell lines. In vivo tumor growth suppression was determined with human myeloma (MM.1R) xenografts in athymic mice. In addition, we provide evidence that SF1126 has pharmacodynamic activity in the treatment of patients with MM.. SF1126 was cytotoxic to all tested MM lines, and potency was augmented by the addition of bortezomib. SF1126 affected MM.1R cell line signaling in vitro, inhibiting phospho-AKT, phospho-ERK, and the hypoxic stabilization of HIF1α. Tumor growth was 94 % inhibited, with a marked decrease in both cellular proliferation (PCNA immunostaining) and angiogenesis (tumor microvessel density via CD31 immunostaining). Our clinical results demonstrate pharmacodynamic knockdown of p-AKT in primary patient-derived MM tumor cells in vivo.. Our results establish three important points: (1) SF1126, a pan-PI3K inhibitor has potent antitumor activity against MM in vitro and in vivo, (2) SF1126 displays augmented antimyeloma activity when combined with proteasome inhibitor, bortezomib/Velcade(®), and (3) SF1126 blocks the IGF-1-induced activation of AKT in primary MM tumor cells isolated from SF1126-treated patients The results support the ongoing early Phase I clinical trial in MM and suggest a future Phase I trial in combination with bortezomib in hematopoietic malignancies.

Topics: Animals; Antineoplastic Agents; Caspases; Chromones; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Integrins; Mice; Multiple Myeloma; Oligopeptides; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Xenograft Model Antitumor Assays

Bromodomain-containing protein 4 (BRD4), an epigenetic reader of acetyl lysine, has emerged as a promising therapeutic target for many diseases including cancer, inflammation and heart failure. Our previous study reported that nitroxoline, an FDA approved antibiotic, showed potential BRD4 inhibitory activity and antiproliferation activity against leukemia cell lines. In this study, we further explored the structure-activity relationship (SAR) around nitroxoline and employed our previously developed machine learning based activity scoring function BRD4LGR for further analysis. To improve the cellular level activity, physico-chemical properties were optimized using computational approaches. Then the candidates were tested for their ADME/T profiles. Finally, based on this rational hit-to-lead optimization strategy, 3 drug-like BRD4 inhibitors were obtained, with different profiles on cell line selectivity for multiple myeloma, leukemia and triple negative breast cancer. Further mechanism study showed these compounds could down-regulate c-Myc to inhibit cancer cell growth. This work illustrates the application of multiple computer-aided drug design techniques in a hit-to-lead optimization scenario, and provides novel potent BRD4 inhibitors with different phenotype propensities for future cancer treatment.

Topics: Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Computer-Aided Design; Drug Design; Humans; Imidazoles; Leukemia; Multiple Myeloma; Nitroquinolines; Nuclear Proteins; Proto-Oncogene Proteins c-myc; Quinolines; Structure-Activity Relationship; Transcription Factors; Triple Negative Breast Neoplasms