A novel tropomyosin-related kinase A inhibitor, KK5101 to treat pancreatic cancer.

Tropomyosin-related kinase A (TrkA) plays important roles in tumor cell growth and survival signaling and contributes to chemo-resistance in pancreatic cancer. Therefore, we developed KK5101, a novel TrkA target inhibitor and assessed its anti-cancer effects and investigated underlying mechanism of action in pancreatic cancer. KK5101 was characterized to inhibit TrkA selectively and potently by protein binding assay. It effectively inhibited the growth and proliferation of pancreatic cancer cells. Also, KK5101 increased apoptosis with loss of mitochondrial membrane potential, as evidenced by increases of cytochrome c releases. It increased numbers of TUNEL-positive apoptotic cells, and cell death including early and late apoptosis by Annexin V assay. In addition, activation of the TrkA signaling cascades including p-AKT, p-MEK, and p-STAT3 were inhibited by KK5101 treatment in vitro, as well as ex vivo tumor spheroid models, resulting in potent induction of apoptosis. Importantly, KK5101 also significantly attenuated tumor growth of in vivo pancreatic cancer models. These findings indicate that KK5101 may exert antitumor effects by directly affecting cancer cell growth or survival via inhibition of TrkA signaling pathway. We therefore suggest that KK5101 is a novel therapeutic candidate for treating pancreatic cancer.

Design and synthesis of new 2-anilinoquinolines bearing N-methylpicolinamide moiety as potential antiproliferative agents.

A series of new 2-anilinoquinolines 6a-o possessing the substantial N-methylpicolinamide motif at C5 has been designed and synthesized as sorafenib analogs. The antiproliferative activities of the target compounds were preliminarily appraised against a panel of three human cancer cell lines (MCF-7, SK-BR3, and HCT116), and a selected array was further tested over a panel of approximately 60 cancer cell lines at NCI at 10 µM concentration. Interestingly, compounds 6c, 6d, 6j, 6k, and 6l showed promising selective anticancer activities (growth inhibition >80%) toward certain cancer cells at 10 µM testing dose. Compounds 6d and 6j were advanced to five-dose testing mode to determine their GI50 values and compared with our previously reported ureidoquinoline B and sorafenib as reference compounds. The 4-chloro-3-trifluoromethylaniline derivative 6j manifested superior potency than both compound B and sorafenib over eleven and eight cell lines, respectively. It showed GI50 values of 0.36, 0.66, 0.68, and 0.60 µM against the breast MDA-MB-468, renal A498, and melanoma SK-MEL-5 and UACC-62 cell lines, respectively. Moreover, both 6d and 6j exerted low cytotoxic effects against HFF-1 normal cell line. Furthermore, compounds 6d and 6j were tested against both B-RafV600E and C-Raf kinases and displayed modest inhibitory activities, which were justified by molecular docking study. Compound 6j could serve as a promising candidate for further development of potent anticancer chemotherapeutics.

Discovery of a Nanomolar Multikinase Inhibitor (KST016366): A New Benzothiazole Derivative with Remarkable Broad-Spectrum Antiproliferative Activity.

Herein we report the discovery of compound 6 [KST016366; 4-((2-(3-(4-((4-ethylpiperazin-1-yl)methyl)-3-(trifluoromethyl)phenyl)ureido)benzo[d]thiazol-6-yl)oxy)picolinamide] as a new potent multikinase inhibitor through minor structural modification of our previously reported RAF kinase inhibitor A. In vitro anticancer evaluation of 6 showed substantial broad-spectrum antiproliferative activity against 60 human cancer cell lines. In particular, it showed GI50 values of 51.4 and 19 nm against leukemia K-562 and colon carcinoma KM12 cell lines, respectively. Kinase screening of compound 6 revealed its nanomolar-level inhibitory activity of certain oncogenic kinases implicated in both tumorigenesis and angiogenesis. Interestingly, 6 displays IC50 values of 0.82, 3.81, and 53 nm toward Tie2, TrkA, and ABL-1 (wild-type and T315I mutant) kinases, respectively. Moreover, 6 is orally bioavailable with a favorable in vivo pharmacokinetic profile. Compound 6 may serve as a promising candidate for further development of potent anticancer chemotherapeutics.

Novel 5-substituted-2-anilinoquinolines with 3-(morpholino or 4-methylpiperazin-1-yl)propoxy moiety as broad spectrum antiproliferative agents: Synthesis, cell based assays and kinase screening.

A series of new 2-anilinoquinolines possessing 3-(morpholino or 4-methylpiperazin-1-yl)propoxy moiety at C5 of quinoline has been designed and synthesized as potential anticancer agents. Their antiproliferative activities were evaluated against a panel of 60 cancer cell lines at NCI and compared with gefitinib as a reference compound. Most of the tested compounds displayed potent and broad spectrum antiproliferative activities. Compounds 7d, 7f and 7g showed strong inhibitory and lethal effects at 10µM concentration. Moreover, they manifested superior potencies and efficacies than gefitinib across the most tested cell lines. Compound 7d, with 4-chloro-3-trifluoromethylphenyl group, proved to be the most potent and efficacious derivative in this series, with mean GI50 and TGI values of 1.62µM and 3.47µM, respectively. Kinase screening of 7d against a panel of 47 oncogenic kinases revealed its selective inhibitory effect (96% inhibition) towards TrkA kinase. Furthermore, the most potent compounds showed low cytotoxic effects against HFF-1 normal cell line.

Design and synthesis of new potent anticancer benzothiazole amides and ureas featuring pyridylamide moiety and possessing dual B-Raf(V600E) and C-Raf kinase inhibitory activities.

A new series of benzothiazole amide and urea derivatives tethered with the privileged pyridylamide moiety by ether linkage at the 6-position of benzothiazole (22 final compounds) has been designed and synthesized as potent anticancer sorafenib analogs. A selected group of twelve derivatives was appraised for its antiproliferative activity over a panel of 60 human cancer cell lines at a single dose concentration of 10 µM at National Cancer Institute (NCI, USA). Compounds 4b, 5a, 5b and 5d exhibited promising growth inhibitions and thus were further tested in advanced 5-dose testing assay to determine their GI50 values. The cellular based assay results revealed that 3,5-bis-trifluoromethylphenyl (5b) urea member is the best derivative with superior potency and efficacy compared to sorafenib as well as notable extended spectrum activity covering 57 human cancer cell lines. Kinase screening of compound 5b showed its kinase inhibitory effect against both B-Raf(V600E) and C-Raf. Moreover, the most potent derivatives in cells were investigated for their RAF inhibitory activities, and the results were rationalized with the molecular docking study. Profiling of CYP450 and hERG channel inhibitory effects for the active compounds revealed their low possibilities to exhibit undesirable drug-drug interactions and cardiac side effects.

Design, synthesis, in-vitro antiproliferative activity and kinase profile of new picolinamide based 2-amido and ureido quinoline derivatives.

New 2-amido and ureido quinoline derivatives substituted with 2-N-methylamido-pyridin-4-yloxy group at the 5-position of quinoline (18 final compounds) have been designed and synthesized as anticancer sorafenib congeners. Among the synthesized derivatives, fourteen compounds were selected for evaluation of their antiproliferative activity over a panel of 60 cancer cell lines at a single dose concentration of 10 µM at National Cancer Institute (NCI, USA). Four compounds, 9b-d and 9f showed promising mean growth inhibitions and thus were further tested at five-dose testing mode to determine their IC50 values. The data revealed that 2,4-difluorophenyl (9b) and 4-chloro-3-trifluoromethylphenyl (9d) urea compounds are the most active derivatives with significant efficacies and superior potencies than sorafenib in 36 and 12 cancer cell lines, respectively, belonging particularly to renal carcinoma cell (RCC), ovarian, and non small cell lung cancer (NSCL). Compound 9b and 9d were found to be six and two times more potent than sorafenib against A498 RCC line, with IC50 values of 0.42 µM and 1.36 µM, respectively. Accordingly, compound 9d was screened over a panel of 41 oncogenic kinases at a single dose concentration of 10 µM to profile its kinase inhibitory activity. Interestingly, the compound showed highly selective inhibitory activities ( 81.8% and 96.3%) against BRAF(V600E) and C-RAF kinases with IC50 values of 316 nM and 61 nM, respectively. In addition, molecular docking, cell cycle analysis, compliance to Lipinski's rule of five, and in silico toxicity assessment have been reported.

ABL kinase inhibitory and antiproliferative activity of novel picolinamide based benzothiazoles.

A series of novel picolinamide based benzothiazoles (17 final compounds), targeting both wild-type and the most resistant T315I mutant of Bcr-Abl kinase, has been designed and synthesized. Moreover, a selected array (8 compounds) was evaluated for its antiproliferative activity over a panel of 60 cancer cell lines. Compound 5l was the most potent derivative against both native and T315I mutant ABL with IC50 values of 18.2 and 39.9nM, respectively, and showed highly selective inhibitory activity (89.8%) towards the Bcr-Abl dependent leukemia cell (K-562) at 10µM concentration. Significance of C6-oxypicolinamide moiety and SAR study for the C2 aliphatic side chain of benzothiazole are discussed in detail.