Kwangho Lee

Novel bis-ortho-alkoxy-para-piperazinesubstituted-2,4-dianilinopyrimidines (KRCA-0008) as potent and selective ALK inhibitors for anticancer treatment

The synthesis of bis-ortho-alkoxy-para-piperazinesubstituted-2,4-dianilinopyrimidines is described and their structure-activity-relationship to anaplastic lymphoma kinase (ALK) is presented. KRCA-0008 is selective and potent to ALK and Ack1, and displays drug-like properties without hERG liability. KRCA-0008 demonstrates in vivo efficacy comparable to Crizotinib in xenograft mice model.

Synthesis and structure–activity relationship of aminopyridines with substituted benzoxazoles as c-Met kinase inhibitors

A series of hydroxybenzoxazole derivatives was synthesized, and their c-Met kinase inhibitory activity was evaluated. Described herein is a potent c-Met inhibitor by structural modification of the parent benzoxazole scaffold, with particular focus on the hydroxyl substituent of the benzoxazole moiety.

Design and synthesis of 3-(4,5,6,7-tetrahydro-3H-imidazo[4,5-c]pyridin-2-yl)-1H-quinolin-2-ones as VEGFR-2 kinase inhibitors.

A series of 3-(4,5,6,7-tetrahydro-3H-imidazo[4,5-c]pyridin-2-yl)-1H-quinolin-2-ones have been identified as a new class of VEGFR-2 kinase inhibitors. A variety of (4,5,6,7-tetrahydro-imidazo[5,4-c]pyridin-2-yl)-acetic acid ethyl esters were synthesized, and their VEGFR-2 inhibitory activity was evaluated. Described herein are the preparation of the series and the effects of the compounds on VEGFR-2 kinase activity.

ALK inhibitors of bis- ortho -alkoxy- para -piperazinesubstituted-pyrimidines and -triazines for cancer treatment

Syntheses of various bis-ortho-alkoxy-para-piperazineanilino-pyrimidines and -triazines of KRCA-0008 analogs are described and their structure–activity-relationship to anaplastic lymphoma kinase (ALK) is discussed. 5-trifluoromethyl-2,4-pyrimidine analog (2) seems to be most potent in both biochemical and cellular assay in this study, however it shows inferior mice xenograft activity to Crizotinib presumably due to its sub-optimal PK parameters. 4,6-disubstituted pyrimidine and 2,4-disubstituted triazine derivatives of KRCA-0008 are less potent or inactive to ALK wt., and this observation is explained with their molecular modeling compared to KRCA-0008.

Novel 2,4-dianilino-5-fluoropyrimidine derivatives possessing ALK inhibitory activities

A new series of 2,4-dianilino-5-fluoropyrimidine derivatives were designed and synthesized and their anaplastic lymphoma kinase (ALK) inhibitory activities were evaluated by biochemical and cell-based assays in order to discover a new ALK inhibitor. Most compounds synthesized showed good inhibitory activities against ALK and good cytotoxic activities in H3122 cell line. The best compound 6f showed good activity against wild-type ALK along with crizotinib-resistant mutant ALK, and it showed 6 times better activity in cell-based assay than crizotinib. Some SAR studies were performed by the comparisons of the activities between 6 and the designed-synthesized compounds.

Discovery of novel [1,2,4]triazolo[4,3-a]quinoxaline aminophenyl derivatives as BET inhibitors for cancer treatment

Bromodomain and extra-terminal (BET) proteins, a class of epigenetic reader domains has emerged as a promising new target class for small molecule drug discovery for the treatment of cancer, inflammatory, and autoimmune diseases. Starting from in silico screening campaign, herein we report the discovery of novel BET inhibitors based on [1,2,4]triazolo[4,3-a]quinoxaline scaffold and their biological evaluation. The hit compound was optimized using the medicinal chemistry approach to the lead compound with excellent inhibitory activities against BRD4 in the binding assay. The substantial antiproliferative activities in human cancer cell lines, promising drug-like properties, and the selectivity for the BET family make the lead compound (13) as a novel BRD4 inhibitor motif for anti-cancer drug discovery.

Novel indazole-based small compounds enhance TRAIL-induced apoptosis by inhibiting the MKK7-TIPRL interaction in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most malignant tumors. Although various treatments, such as surgery and chemotherapy, have been developed, a novel alternative therapeutic approach for HCC therapy is urgently needed. Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a promising anti-cancer agent, but many cancer cells are resistant to TRAIL-induced apoptosis. To help overcome TRAIL resistance in HCC cancer cells, we have identified novel chemical compounds that act as TRAIL sensitizers. We first identified the hit compound, TRT-0002, from a chemical library of 6,000 compounds using a previously developed high-throughput enzyme-linked immunosorbent assay (ELISA) screening system, which was based on the interaction of mitogen-activated protein kinase kinase 7 (MKK7) and TOR signaling pathway regulator-like (TIPRL) proteins and a cell viability assay. To increase the efficacy of this TRAIL sensitizer, we synthesized 280 analogs of TRT-0002 and finally identified two lead compounds (TRT-0029 and TRT-0173). Co-treating cultured Huh7 cells with either TRT-0029 or TRT-0173 and TRAIL resulted in TRAIL-induced apoptosis due to the inhibition of the MKK7-TIPRL interaction and subsequent phosphorylation of MKK7 and c-Jun N-terminal kinase (JNK). In vivo, injection of these compounds and TRAIL into HCC xenograft tumors resulted in tumor regression. Taken together, our results suggest that the identified lead compounds serve as TRAIL sensitizers and represent a novel strategy to overcome TRAIL resistance in HCC.

Abstract A287: Discovery of c-Met kinase inhibitors for anticancer therapeutics.

c-Met recepter tyrosine kinase (RTK) and its ligand, hepatocyte growth factor (HGF), have been reported to be involved in tumorigenesis and metastatic progression. Also, aberrant c-Met signaling has been reported in a wide variety of cancers such as gastric, lung, colon, breast, bladder, head and neck, ovarian, prostate, thyroid, pancreatic, hematological malignancies, and central nervous system tumors. We have synthesized a series of triazolopyridazine derivatives and their c-Met (mesenchymal-epithelial transition factor) inhibitory activities have been evaluated. A potent c-Met kinase inhibitor by structural modification of the parent pyrimidine scaffold with particular focus on the aryl substituent on the triazolopyridazines will be discussed. Several triazolopyridazine derivatives were found to be potent as c-Met inhibitors in enzyme assays and cell-based assays (c-Met addicted cell lines). We found KRC-00831 is a highly potent and selective c-Met receptor tyrosine kinase inhibitor over other kinases (c-Met enzyme, IC50=3 nM) and exhibit excellent cellular activities in c-Met driven cell lines (Hs746T, GI50=0.1 nM; H1993, GI50=27 nM, MKN45, GI50=15 nM; SNU-5, GI50=8 nM). KRC-00831 is chemically and metabolically very stable and showed no CYP inhibition, hERG binding activity. KRC-00831 strongly suppressed the growth of c-Met over-expressed cancer cells, while not in c-Met absent cancer cell lines. In xenograft animal models, we observed not only dose dependent tumor growth inhibitions but complete tumor regressions. In summary, we suggest that KRC-00831 wil be a novel drug candidate with the therapeutic potential of targeting c-Met in human cancer. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A287. Citation Format: Chang-Soo Yun, Sung Yun Cho, Hyoung Rae Kim, Hee Jung Jung, Jae Du Ha, Kwangho Lee, Pilho Kim, Chi Hoon Park, Chong Ock Lee. Discovery of c-Met kinase inhibitors for anticancer therapeutics. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A287.

Abstract A284: Anaplastic lymphoma kinase (ALK) inhibitors for cancer treatment.

Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase, has been recently elucidated as a potential target for various cancers due to its implications of tumorigenesis by ALK gene mutations, overexpressions, and amplifications. ALK was first identified in 1994 as a part of nucleophosmin NPM-ALK fusion gene in 60% of anaplastic large-cell lymphoma (ALCL). In late 2007, EML4-ALK fusion gene was found in 3∼7% of non-small cell lung cancer (NSCLC), and a kind of ALK fusion genes are found one by one in various cancers such as DLBCL, inflammatory myofiblastic tumor (IMT), plasmacytoma, esophageal cancer, and ovarian cancer. More over mutated ALK is much implicated in neuroblastoma and thyroid carcinoma. Crizotinib (Xalkori) was the first small molecule inhibitor which was approved as a treatment of NSCLC including ALK fusion gene by FDA in 2011. Crizotinib, a potent inhibitor of both c-Met and ALK tyrosine kinases is a 3-benzyloxy-2-aminopyridine derivative derived from c-Met inhibitors and surprisingly its overall clinical benefit was 57 %. However, its clinical efficacy is limited by drug-resistance mutations, particularly the gatekeeper L1196M mutation. Unlike their aminopyridine-based core scaffold, a pyrimidine-based inhibitor has been identified for the ALK-related inhibition and shown a potent activity to EML4-ALK wild type and other mutants including EML4-ALK L1196M. In this paper, we designed and synthesized a new series of pyrimidine derivatives to discover a new ALK inhibitor which is well-matched with crizotinib and LDK378 in docking study. KRCA-0008 has been identified as a highly potent and selective ALK inhibitor with potency profiles (ALK wt, IC50=12 nM). It has excellent activities both ALK mutants (L1196M, C1156Y, F1174L, R1275Q) and BaF3 ALK L1196M cell line. PK profiles were excellent and KRCA-0008 was safe in Ames test, chromosomal aberration assay, micronucleus asssay, and acute toxicity. Also, we observed KRCA-0008 is chemically and metabolically very stable and no CYP and hERG inhibitions. In vivo xenograft mouse model (H3122 NSCLC) model study, KRCA-0008 shows moderate tumor growth inhibition without significant body weight change. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A284. Citation Format: Kwangho Lee, Hyoung Rae Kim, Sung Yun Cho, Hee Jung Jung, Jae Du Ha, Chang-Soo Yun, Pilho Kim, Chi Hoon Park, Chong Ock Lee. Anaplastic lymphoma kinase (ALK) inhibitors for cancer treatment. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A284.