Novel Pan-Pim Kinase Inhibitors With Imidazopyridazine and Thiazolidinedione Structure Exert Potent Antitumor Activities.

Pim kinases are overexpressed in various types of hematological malignancies and solid carcinomas, and promote cell proliferation and survival. Here in this study, we investigated the preclinical profile of novel pan-Pim kinase inhibitors with imidazopyridazine and thiazolidinedione structure. Imidazopyridazine-thiazolidinediones inhibited activities of Pim kinases with IC50 values of tens to hundreds nanomolar. With YPC-21440 and/or YPC-21817, which exhibited especially high inhibitory activities against Pim kinases, we investigated in vitro and in vivo activities of imidazopyridazine-thiazolidinediones. In silico analysis of binding mode of YPC-21440 and Pim kinases revealed that it directly bound to ATP-binding pockets of Pim kinases. In the kinase panel tested, YPC-21440 and YPC-21817 were highly specific to Pim kinases. These compounds exerted antiproliferative activities against various cancer cell lines derived from hematological malignancies and solid carcinomas. Furthermore, they suppressed phosphorylation of Pim kinase substrates, arrested cell cycle at the G1 phase, and induced apoptosis in cultured cancer cells. In tumor xenograft models, YPC-21440 methanesulfonate and YPC-21817 methanesulfonate exerted antitumor activities. Furthermore, pharmacodynamic analysis with a xenograft model suggested that YPC-21817 methanesulfonate inhibited Pim kinases in tumors. In conclusion, our data revealed that imidazopyridazine-thiazolidinediones are novel Pim kinases inhibitors, effective on various types of cancer cell lines both in vitro and in vivo.

Rational Design of a Potent Pan-Pim Kinases Inhibitor with a Rhodanine-Benzoimidazole Structure.

BACKGROUND/AIM: The serine/threonine Pim kinases are overexpressed in various types of solid carcinomas and hematological malignancies, and contribute to regulating cell-cycle progression and cell survival. The aim of this study was to discover a novel pan-Pim kinases inhibitor with potent anti-proliferative activities against cancer cell lines. MATERIALS AND METHODS: We screened a panel of small molecule compounds for their ability to inhibit Pim-1 kinase activity, and the hit compound was optimized using the docking analysis to Pim-1. We evaluated kinase-inhibition activities of the rationally-designed compound against Pim-1, 2, 3 and another five kinases. Furthermore, in order to characterize the cellular activities, both solid and hematological cancer cell lines treated with the compound were subjected to anti-proliferative assay, western blotting, FACS and apoptosis assays. RESULTS: We discovered a pan-Pim kinases inhibitor, compound 1, with a rhodanine-benzylidene structure via Pim-1 inhibitor screening. Using docking analysis of compound 1 and Pim-1, we optimized it and found a potent- and selective-Pim kinases inhibitor, compound 2, with a rhodanine-benzoimidazole structure. Compound 2 inhibited Pim-1, 2, 3 with IC50 values of 16, 13, and 6.4 nM, respectively, and suppressed proliferation of solid and hematological cancer cell lines at submicromolar concentrations. In both types of cell lines, compound 2 inhibited phosphorylation of Pim signaling substrates and cell-cycle progression and induced apoptosis. CONCLUSION: We identified a pan-Pim kinases inhibitor, compound 2, with a rhodanine-benzoimidazole structure. Our data suggest that compound 2 can serve as a lead to novel anticancer agents, effective in the treatment of both solid carcinomas and hematological malignancies.

Palladium(II)-Catalyzed Intramolecular Aminocarbonylation of endo-Carbamates under Wacker-Type Conditions.

Pd(II)-catalyzed intramolecular aminocarbonylation of olefins bearing many types of nitrogen nucleophiles has been examined under two typical conditions: acidic conditions [conditions A, typically PdCl(2) (0.1 equiv) and CuCl(2) (3.0 equiv) under 1 atm of CO at room temperature in methanol] and buffered conditions [conditions B, typically PdCl(2) (0.1 equiv) and CuCl(2) (2.3 equiv) under 1 atm of CO at 30 degrees C in trimethyl orthoacetate]. Among nitrogen nucleophiles, endo-carbamates 7 display distinctive reactivity: endo-carbamates 7a-k smoothly undergo intramolecular aminocarbonylation under conditions B to furnish 4-[(methoxycarbonyl)methyl]-2-oxazolidinones 8a-k in good yields, while they would not undergo the expected reaction under conditions A. Other nitrogen nucleophiles (exo-ureas 1, endo-ureas 3, exo-carbamates 5, and exo-tosylamides 9), on the other hand, satisfactorily undergo aminocarbonylation only under conditions A to give rise to 2, 4, 6, and 10, respectively, in good yields. Under conditions B, they are unreactive and provide either the expected products in poor yields or intractable mixtures of products. On the basis of this contrasting reactivity between endo-carbamates and other nitrogen nucleophiles, the chemoselective aminocarbonylation of 7l-o has been achieved; aminocarbonylation takes place at the endo-carbamate moieties to furnish 8l-o exclusively under conditions B, and aminocarbonylation occurs at the exo-carbamate, exo-urea, and exo-tosylamide moieties to yield 13a-d exclusively under conditions A.