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This file contains Supplemental figures, tables, and legends that accompany the main figures, as indicated in each legend. There are 3 supplemental tables and 6 supplemental figures. Table S1. List of potential target of the GNS compounds that were profiled in Figure 1 of the main text. Table S2. Half-maximal inhibitor concentration of the EGFR inhibitors tested. Table S3. Blood-brain-barrier penetration of the GNS compounds as assessed by the indicated pharmacokinetic measurements. Figure S1. Structural modeling studies show the binding characteristics of the indicated EGFR inhibitors. Figure S2. The effects of each EGFR inhibitor in the cell lines expressing mutant or wild type EGFR. Figure S3. In vivo effects of the GNS compounds. Figure S4. In vivo anti-tumor effects of the GNS compounds. Figure S5. In vivo anti-tumor effects of the GNS compounds in intracranial EGFR-mutant lung cancer. Figure S6. In vivo anti-tumor effects of the indicated EGFR inhibitors in intracranial EGFR-mutant lung cancer.

Supplementary Figure legend

The clinical utility of approved EGFR small-molecule kinase inhibitors is plagued both by toxicity against wild-type EGFR and by metastatic progression in the central nervous system, a disease sanctuary site. Here, we report the discovery and preclinical efficacy of GNS-1486 and GNS-1481, two novel small-molecule EGFR kinase inhibitors that are selective for T790M-mutant isoforms of EGFR. Both agents were effective in multiple mouse xenograft models of human lung adenocarcinoma (T790M-positive or -negative), exhibiting less activity against wild-type EGFR than existing approved EGFR kinase inhibitors (including osimertinib). In addition, GNS-1486 showed superior potency against intracranial metastasis of EGFR-mutant lung adenocarcinoma. Our results offer a preclinical proof of concept for new EGFR kinase inhibitors with the potential to improve therapeutic index and efficacy against brain metastases in patients. Cancer Res; 77(5); 1200–11. ©2017 AACR.

Supplementary Figure S1,S2,and S3

Purpose: Given that osimertinib is the only approved third-generation EGFR-TKI against EGFR activating and resistant T790M mutated non–small cell lung cancer (NSCLC), additional mutant-selective inhibitors with a higher efficacy, especially for brain metastases, with favorable toxicity profile are still needed. In this study, we investigated the antitumor efficacy of YH25448, an oral, mutant-selective, irreversible third-generation EGFR-TKI in preclinical models. Experimental Design: Antitumor activity of YH25448 was investigated in vitro using mutant EGFR-expressing Ba/F3 cells and various lung cancer cell lines. In vivo antitumor efficacy, ability to penetrate the blood–brain barrier (BBB), and skin toxicity of YH25448 were examined and compared with those of osimertinib using cell lines and PDX model. Results: Compared with osimertinib, YH25448 showed a higher selectivity and potency in kinase assay and mutant EGFR-expressing Ba/F3 cells. In various cell line models harboring EGFR activating and T790M mutation, YH25448 effectively inhibited EGFR downstream signaling pathways, leading to cellular apoptosis. When compared in vivo at equimolar concentrations, YH25448 produced significantly better tumor regression than osimertinib. Importantly, YH25448 induced profound tumor regression in brain metastasis model with excellent brain/plasma and tumor/brain area under the concentration–time curve value. YH25448 rarely suppressed the levels of p-EGFR in hair follicles, leading to less keratosis than osimertinib in animal model. The potent systemic and intracranial activity of YH25448 has been shown in an ongoing phase I/II clinical trial for advanced EGFR T790M mutated NSCLC (NCT03046992). Conclusions: Our findings suggest that YH25448 is a promising third-generation EGFR inhibitor, which may be more effective and better tolerated than the currently approved osimertinib.

Spleen tyrosine kinase (SYK) is a cytosolic non-receptor protein tyrosine kinase that mediates key signal transduction pathways following the activation of immune cell receptors. SYK regulates cellular events induced by the B cell receptor and Fc receptors with high intrinsic activity. Furthermore, SYK has been regarded as an attractive target for the treatment of autoimmune diseases and cancers. Here, we report the crystal structures of SYK in complex with seven newly developed inhibitors (G206, G207, O178, O194, O259, O272, and O282) to provide structural insights into which substituents of the inhibitors and binding regions of SYK are essential for lead compound optimization. Our kinase inhibitors exhibited high inhibitory activities against SYK, with half-maximal inhibitory concentrations (IC50) of approximately 0.7–33 nM, but they showed dissimilar inhibitory activities against KDR, RET, JAK2, JAK3, and FLT3. Among the seven SYK inhibitors, O272 and O282 exhibited highly specific inhibitions against SYK, whereas O194 exhibited strong inhibition of both SYK and FLT3. Three inhibitors (G206, G207, and O178) more efficiently inhibited FLT3 while still substantially inhibiting SYK activity. The binding mode analysis suggested that a highly selective SYK inhibitor can be developed by optimizing the functional groups that facilitate direct interactions with Asn499. This article is protected by copyright. All rights reserved.

Spleen tyrosine kinase (SYK) is a cytosolic non-receptor protein tyrosine kinase. Because SYK mediates key receptor signaling pathways involving the B cell receptor and Fc receptors, SYK is an attractive target for autoimmune disease and cancer treatments. To date, representative oral SYK inhibitors, including fostamatinib (R406 or R788), entospletinib (GS-9973), cerdulatinib (PRT062070), and TAK-659, have been assessed in clinical trials. Here, we report the crystal structures of SYK in complex with two newly developed inhibitors possessing 4-aminopyrido[4,3-D]pyrimidine moieties (SKI-G-618 and SKI-O-85). One SYK inhibitor (SKI-G-618) exhibited moderate inhibitory activity against SYK, whereas the other inhibitor (SKI-O-85) exhibited a low inhibitory profile against SYK. Binding mode analysis indicates that a highly potent SYK inhibitor might be developed by modifying and optimizing the functional groups that interact with Leu377, Gly378, and Val385 in the G-loop and the nearby region in SYK. In agreement with our structural analysis, one of our SYK inhibitor (SKI-G-618) shows strong inhibitory activities on the β-hexosaminidase release and phosphorylation of SYK/Vav in RBL-2H3 cells. Taken together, our findings have important implications for the design of high affinity SYK inhibitors.

The clinical utility of approved EGFR small-molecule kinase inhibitors is plagued both by toxicity against wild-type EGFR and by metastatic progression in the central nervous system, a disease sanctuary site. Here, we report the discovery and preclinical efficacy of GNS-1486 and GNS-1481, two novel small-molecule EGFR kinase inhibitors that are selective for T790M-mutant isoforms of EGFR. Both agents were effective in multiple mouse xenograft models of human lung adenocarcinoma (T790M-positive or -negative), exhibiting less activity against wild-type EGFR than existing approved EGFR kinase inhibitors (including osimertinib). In addition, GNS-1486 showed superior potency against intracranial metastasis of EGFR-mutant lung adenocarcinoma. Our results offer a preclinical proof of concept for new EGFR kinase inhibitors with the potential to improve therapeutic index and efficacy against brain metastases in patients. Cancer Res; 77(5); 1200–11. ©2017 AACR.

Introduction: Aberrant AXL expression plays a critical role in cancer cell migration, metastasis and drug resistance. Researchers have revealed that AXL signaling is also over expressed on cells associated with tumor microenvironment. These findings highlight AXL as an attractive drug candidate for targeting tumor evasion and metastasis. Here we present SKI-G-801, a small molecule inhibitor that targets phosphorylation of AXL (IC50 = 20 nM) and its downstream signals. Methods: Inhibitory effects of SKI-G-801 on cancer viability (MTT and colony formation assay), invasion and migration (trans-well invasion assay) were examined in AXL high-expressing lung cancer cells in vitro. LLC2 lung and 4T1 breast cancer bearing mouse models were established. in addition, C57BL/6 mice were injected intravenously with B16F10 melanoma cells to establish lung metastasis model. Mice were administrated with 30 mg/kg of SKI-G-801 orally before (metastasis model) or after (syngeneic model) tumor injection. To elucidate the involvement of AXL inhibitor on tumor microenvironment, the population of T cells and myeloid cells was analyzed by flow cytometry from the LLC2 tumor. Results: Treatment of SKI-G-801 showed strong inhibition of cancer migration and invasion, when its direct killing effect on cancer cells was modest. These results were reproduced in vivo test that pretreatment of SKI-G-801 significantly reduced metastatic burden in B16F10 model (p < 0.05). LLC2 and 4T1 tumors were decreased in SKI-G-801 treatment group (p < 0.05), but not in anthemic nude mice. CD3+CD8+ T cell population and memory Tc cells were increased in SKI- G-801 treatment group (p < 0.05). Especially, granzyme B+ Tc and gp70+ tumor specific Tc were increased (p < 0.05). SKI-G-801 increase the helper T cell population; CD3+CD4+ (p < 0.05), and CD44+ memory Th cells (p < 0.01). Conclusion: SKI-G-801 demonstrates great potential in anti-cancer activity though immune responses. The anti-cancer effects lead to a reversal of the metastatic phenotype in animal model. Our results suggest that SKI-G-801 is a promising drug for prevention against metastatic cancer. Citation Format: Chun-Feng Xin, Sung Eun Kim, Kyoung-Ho Pyo, Ha Ni Jo, Jae Seok Cho, Jae Hwan Kim, Wongeun Lee, Hee Kyu Lee, Jung-Ho Kim, Ho-Juhn Song, Jong Sung Koh, Byoung Chul Cho. SKI-G-801, an AXL kinase inhibitor, blocks metastasis and induces anti-tumor immune responses in various syngeneic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2010.

The fruitless (fru) gene in Drosophila melanogaster is a multifunctional gene that has sex-specific functions in the regulation of male sexual behavior and sex-nonspecific functions affecting adult viability and external morphology. While much attention has focused on fru's sex-specific roles, less is known about its sex-nonspecific functions. We have examined fru's sex-nonspecific role in embryonic neural development. fru transcripts from sex-nonspecific promoters are expressed beginning at the earliest stages of neurogenesis, and Fru proteins are present in both neurons and glia. In embryos that lack most or all fru function, FasII- and BP102-positive axons have defasciculation defects and grow along abnormal pathways in the CNS. These defects in axonal projections in fru mutants were rescued by the expression of specific UAS-fru transgenes under the control of a pan-neuronal scabrous-GAL4 driver. Our results suggest that one of fru's sex-nonspecific roles is to regulate the pathfinding ability of axons in the embryonic CNS.

EGFR mutated lung cancer shows approximately 10-15% of non-small cell lung cancer (NSCLC). Although the best therapeutic EGFR tyrosine kinase inhibitors (TKIs) targeting mutant EGFR, such as gefitinib and erlotinib, are used in the first line treatment of patients with advanced EGFR mutated NSCLC, the acquired resistance to the drugs usually appears in 10-12 months of therapy by the occurrence of a second EGFR mutation T790M. YH25448, a highly mutant-selective and irreversible 3rd generation EGFR TKI potently penetrating blood-brain barrier (BBB) penetration, targets both activating EGFR mutations Del19, L858R and T790M mutation while sparing wild type. In NSCLC cell lines and primary cancer cells from patients harboring EGFR mutations, YH25448 showed more potent inhibition of cancer cell growth and significantly increased tumor cell apoptosis compared to osimertinibs, which is one of 3rd generation EGFR TKIs. In vivo mouse model implanted with H1975 cells, YH25448 treatment at the once-daily showed a dramatic dose-dependent tumor regression in both subcutaneous and intracranial lesions with no abnormal signs such as skin keratosis shown in osimertinib-treated mice. Plasma half life of YH25448 was 5.9-6.8 hr and tumor to plasma AUC0-last ratio was 3.0-5.1 in tumor bearing mice. YH25448 also showed excellent penetration of the BBB, achieving CSF concentrations exceeding the IC50 value for pEGFR inhibition in the tumor-bearing mice. Taken together, these findings suggest important role for the further development of YH25448 as a novel therapeutic for the treatment of EGFR mutant-positive NSCLC patients with brain metastases. Citation Format: Jiyeon Yun, Min Hee Hong, Seok-Young Kim, Chae Won Park, So-Young Kim, Mi Ran Yun, Han Na Kang, Kyoung-Ho Pyo, Jong Sung Koh, Ho-Juhn Song, Young- Sung Lee, Se-Woong Oh, Soongyu Choi, Byoung-Chul Cho. YH25448, an irreversible 3rd generation EGFR TKI, exhibits superior anticancer effects with potent brain BBB penetration in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4790.

A multibranched hierarchy of regulatory genes controls all aspects of somatic sexual development in Drosophila melanogaster. One branch of this hierarchy is headed by the fruitless (fru) gene and functions in the central nervous system, where it is necessary for male courtship behavior as well as the differentiation of a male-specific abdominal structure, the muscle of Lawrence (MOL). A preliminary investigation of several of the mutations described here showed that the fru gene also has a sex-nonspecific vital function. The fru gene produces a complex set of transcripts through the use of four promoters and alternative splicing. Only the primary transcripts produced from the most distal (P1) promoter are sex-specifically spliced under direction of the sex-determination hierarchy. We have analyzed eight new fru mutations, created by X-ray mutagenesis and P-element excision, to try to gain insight into the relationship of specific transcript classes to specific fru functions. Males that lack the P1-derived fru transcripts show a complete absence of sexual behavior, but no other defects besides the loss of the MOL. Both males and females that have reduced levels of transcripts from the P3 promoter develop into adults but frequently die after failing to eclose. Analysis of the morphology and behavior of adult escapers showed that P3-encoded functions are required for the proper differentiation and eversion of imaginal discs. Furthermore, the reduction in the size of the neuromuscular junctions on abdominal muscles in these animals suggests that one of fru's sex-nonspecific functions involves general aspects of neuronal differentiation. In mutants that lack all fru transcripts as well as a small number of adjacent genes, animals die at an early pupal stage, indicating that fru's function is required only during late development. Thus, fru functions both in the sex-determination regulatory hierarchy to control male sexual behavior through sex-specific transcripts and sex-nonspecifically to control the development of imaginal discs and motorneuronal synapses during adult development through sex-nonspecific transcript classes.

Aberrant activations of Fms-like tyrosine receptor kinase (FLT) 3 are implicated in the pathogenesis of 20% to 30% of patients with acute myeloid leukemia (AML). G-749 is a novel FLT3 inhibitor that showed potent and sustained inhibition of the FLT3 wild type and mutants including FLT3-ITD, FLT3-D835Y, FLT3-ITD/N676D, and FLT3-ITD/F691L in cellular assays. G-749 retained its inhibitory potency in various drug-resistance milieus such as patient plasma, FLT3 ligand surge, and stromal protection. Furthermore, it displayed potent antileukemic activity in bone marrow blasts from AML patients regardless of FLT3 mutation status, including those with little or only minor responses to AC220 or PKC412. Oral administration of G-749 yielded complete tumor regression and increased life span in animal models. Thus, G-749 appears to be a promising next-generation drug candidate for the treatment of relapsed and refractory AML patients with various FLT3-ITD/FLT3-TKD mutants and further shows the ability to overcome drug resistance.

Human Pim1 kinase is a serine/threonine protein kinase that plays important biological roles in cell survival, apoptosis, proliferation, and differentiation. Moreover, Pim1 is up-regulated in various hematopoietic malignancies and solid tumors. Thus, Pim1 is an attractive target for cancer therapeutics, and there has been growing interest in developing small molecule inhibitors for Pim1. Here, we describe the crystal structure of Pim1 in complex with a newly developed pyrido[4,3-d]pyrimidine-derivative inhibitor (SKI-O-068). Our inhibitor exhibits a half maximum inhibitory concentration (IC50) of 123 (+/- 14) nM and has an unusual binding mode in complex with Pim1 kinase. The interactions between SKI-O-068 and the Pim1 active site pocket residue are different from those of other scaffold inhibitor-bound structures. The binding mode analysis suggests that the SKI-O-068 inhibitor can be improved by introducing functional groups that facilitate direct interaction with Lys67, which aid in the design of an optimized inhibitor.

Sustained increases in life expectancy have underscored the importance of managing diseases with a high incidence in late life, such as various neurodegenerative conditions. Alzheimer's disease (AD) is the most common among these, and consequently significant research effort is spent on studying it. Although a lot is known about the pathology of AD and the role of β-amyloid (Aβ) peptides, the complete network of interactions regulating Aβ metabolism and toxicity still eludes us. To address this, we have conducted genetic interaction screens using transgenic Drosophila expressing Aβ and we have identified mutations that affect Aβ metabolism and toxicity. These analyses highlight the involvement of various biochemical processes such as secretion, cholesterol homeostasis, and regulation of chromatin structure and function, among others, in mediating toxic Aβ effects. Several of the mutations that we identified have not been linked to Aβ toxicity before and thus constitute novel potential targets for AD intervention. We additionally tested these mutations for interactions with tau and expanded-polyglutamine overexpression and found a few candidate mutations that may mediate common mechanisms of neurodegeneration. Our data offer insight into the toxicity of Aβ and open new areas for further study into AD pathogenesis

Acute myeloid leukemia (AML) is an aggressive cancer, representing 90% of all adult acute leukemias, with an estimated incidence of 200,000 cases each year worldwide. Noticeably malignant cells, in the majority of AML patients, possess aberrantly expressed FLT3. The corresponding tumor-cell genotyping indicates that 25–30% of the AML blasts carry FLT3 mutations. The molecular characterization of these FLT3 mutations has revealed that they contain either internal tandem duplications (FLT3-ITD) in the juxtamembrane region (17–34%) or point mutations at the kinase domain (7%). Therefore, FLT3 has emerged as a promising target in therapy of AML. The first and second generation of the FLT3 inhibitors such as CEP-701, MLN-518, PKC-412, Sunitinib, Sorafenib, and AC220 are under clinical trial for AML treatment. However, their clinical responses have been below expectation likely due to the influence of plasma inhibitory activity, lack of strong inhibition of downstream effectors involved in aberrant activation of growth pathway, and lack of substantial and sustained inhibition of FLT3 activity, consequently resulting in drug resistance. To address and overcome the key issues leading to several known drug resistances, we have developed a series of novel and highly selective FLT3 inhibitors possessing extreme potency against clinically known FLT3-mutants. One of our leads, SKI-G-801 (G-801), showed IC50 of 0.3 nM for FLT3 and IC50 of 2.1 nM in MV4–11 cells. Furthermore, it also showed IC50 of 3.1 nM in model cell line BaF3 expressing FLT3 D835Y whereas AC220 and PKC412 showed IC50s of 52.4 nM and 11.4 nM in the BaF3 cells, respectively. The tight binding property and the high potency of our lead candidates led to a strong inhibitory activity in the cell model in the presence of human plasma; FLT3 phosphorylation was inhibited by G-801 with IC50 of 9.9nM, while by PKC412 with IC50 of >1000 nM in the human plasma. In addition, a significant tumor regression of 85–100% was observed in a mouse xenograft model using MV4–11 cells by G-801 via oral administration for 28 days. Moreover, a synergistic effect of our lead compounds with AraC was more significant in RS4–11 cells than the known FLT3 inhibitors with AraC. These desirable characteristics of our lead candidates would ostensibly overcome the documented drug resistance confronted by previous FLT3 targeted inhibitors such as AC220, PKC-412, and CEP701. One of our lead candidates is expected to enter preclinical study soon. Therefore, we are confident that our lead candidate will be a promising acute myeloid leukemia drug. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C196.