Ting Peng

Discovery and SAR of Thiazolidine-2,4-dione Analogues as Insulin-like Growth Factor-1 Receptor (IGF-1R) Inhibitors via Hierarchical Virtual Screening

Insulin-like growth factor-1 receptor (IGF-1R) is a growth factor receptor tyrosine kinase acting as a critical mediator of cell proliferation and survival. Novel 5-benzylidenethiazolidine-2,4-dione (5) and 5-(furan-2-ylmethylene)thiazolidine-2,4-dione (6) compounds were identified as potent and selective IGF-1R inhibitors via hierarchical virtual screening. Initial SAR and biological activity of the analogues of 5 and 6 with thiazolidine-2,4-dione template are presented, and several inhibitors with low nanomolar potency are reported.

Design, synthesis and biological evaluation of novel 6-alkenylamides substituted of 4-anilinothieno[2,3-d]pyrimidines as irreversible epidermal growth factor receptor inhibitors

A novel series of 6-alkenylamides of 4-anilinothieno[2,3-d]pyrimidine derivatives was designed, synthesized and evaluated as irreversible inhibitors of the epidermal growth factor receptor (EGFR). Most of the compounds exhibited good potency against EGFR wild type (EGFR wt) and EGFR T790M/L858R. Among these, the half-maximal inhibitory concentration (IC50) values of 17 compounds against EGFR wt were less than 0.020μM, and those of 12 compounds were less than 0.010μM. The IC50 values of 10 compounds against EGFR T790M/L858R were less than 0.005μM. Compounds 8l, 9n, 9o, 9q and 9v almost completely blocked the phosphorylation of EGFR in the A431 cell line at 1μM. Compounds 8l, 9n, 9o, 9q and 9v blocked the autophosphorylation of EGFR in NCI-H1975 cells at high concentration (1μM), and compound 8l was confirmed to be an irreversible inhibitor through the dilution method.

Topoisomerase II inhibitors from the roots of Stellera chamaejasme L.

Three new compounds, including one daphnane diterpene (1), one sesquiterpene (6), and one lignan (7) have been isolated from the Stellera chamaejasme L., together with five other known compounds, including four daphnane diterpenenoids (2-5) and one lignan (8). The structures of the new compounds were elucidated by spectroscopic analysis. The cytotoxicities of compounds 1-8 towards human lung adenocarcinoma cells (A549 cells) were evaluated using a sulforhodamine B assay. All of the compounds displayed significant cytotoxicity, with IC₅₀ values in the ranging of 0.2 nM to 2.0 μM. Mechanistic studies revealed that the antitumor activities of compounds 1-3 and 7 were derived from their inhibition of topoisomerase II (Topo II). Furthermore, as a Topo II inhibitor, compound 1 was found to effectively induced G2-M phase cell cycle arrest and apoptosis in cancer cells.

C5-substituted pyrido[2,3-d]pyrimidin-7-ones as highly specific kinase inhibitors targeting the clinical resistance-related EGFRT790M mutant

The development of specific kinase inhibitors has been a long-standing challenge in chemical biology and drug discovery. We have successfully discovered a series of C5-substituted pyrido[2,3-d]pyrimidin-7-ones as highly specific inhibitors against the clinical resistance-related EGFRT790M mutant. One of the most promising compounds, 9f, tightly binds to the EGFRT790M mutant and strongly inhibits its enzymatic function with an IC50 value of 0.80 nM, and displays an extraordinary target specificity with S(35) and S(10) selectivity scores of 0.005 and 0.000, respectively, in a kinase selectivity profiling study against 456 different kinases at 100 nM. The compound also selectively suppresses the proliferation of EGFRT790M mutated H1975 NSCLC cells with an IC50 value of 2.80 nM, but is significantly less toxic to cells with wild-type EGFR. Compound 9f may serve as a promising lead compound for drug discovery overcoming the acquired resistance of NSCLC patients without adverse toxicities.

Naphthalimides exhibit in vitro antiproliferative and antiangiogenic activities by inhibiting both topoisomerase II (topo II) and receptor tyrosine kinases (RTKs)

Novel naphthalimide derivatives were designed and synthesized to modulate both topoisomerase II (topo II) and receptor tyrosine kinases (RTKs). Most target compounds exhibited effective and selective antiproliferative activities against three cancer cell lines by inhibiting topo II. The IC50 values ranged from 1.5 to 19.1 μM. Moreover, compounds 8d and 12d moderately inhibited various angiogenesis-related RTKs, including FGFR1, VEGFR2 and PDGFRα. The representative compound 8d was then proved to possess antiangiogenic activity, which was evidenced by the inhibition of migration and tube formation activities of HMEC-1 cells. To our knowledge, it is the first time naphthalimides were identified as tyrosine kinases inhibitors (TKIs) besides their conventional cytotoxicity.

Design, synthesis and biological evaluation of novel 4-anilinoquinazolines with C-6 urea-linked side chains as inhibitors of the epidermal growth factor receptor

A novel series of anilinoquinazoline compounds with C-6 urea-linked side chains was designed and synthesized as reversible inhibitors of epidermal growth factor receptor (EGFR) based on the structure-activity relationships (SARs) of anilinoquinazoline inhibitors. All compounds demonstrated good inhibition of EGFR wild type (EGFR wt) (IC50=0.024-1.715 μM) and inhibited proliferation of A431cell line (IC50=0.116-22.008 μM). The binding mode of compounds 8a, 8d, 8k and 8o was consistent with the biological results. Moreover, compounds 8k and 8l almost completely blocked the phosphorylation of EGFR in A431 cell line at 0.01 μM. Interestingly, all of the compounds also demonstrated moderate inhibition of EGFR/T790M/L858R (IC50=0.049-5.578 μM). In addition, compounds 8f and 8h blocked the autophosphorylation of EGFR in NCI-H1975 cells at high concentration (10 μM), and compound 8f was confirmed to be an irreversible inhibitor through the dilution method. Importantly, the compounds with C-6 urea-linked side chains which did not contain Michael acceptors demonstrated moderate to strong irreversible EGFR inhibition.

Identification of DW532 as a novel anti-tumor agent targeting both kinases and tubulin

Aim:7,8-Dihydroxy-4-(3-hydroxy-4-methoxyphenyl)-2H-chromen-2-one (DW532) is one of simplified analogues of hematoxylin that has shown broad-spectrum inhibition on tyrosine kinases and in vitro anti-cancer activities. The aim of this study was to identify DW532 as a agent targeting both kinases and tubulin, and to investigate its anti-cancer and anti-angiogenesis activities.Methods:In vitro tyrosine kinases activity was examined with ELISA, and tyrosine kinases activity in cells was evaluated with Western blot analysis. Tubulin turbidity assay, surface plasmon resonance and immunofluorescence technique were used to characterize the tubulin inhibitory activity. Cell proliferation was examined with SRB assay, and cell apoptosis and cell cycle distribution were analyzed with Annexin-V/PI staining and flow cytometry. Tube formation, aortic ring and chick chorioallantoic membrane assays were used to evaluate the anti-angiogenesis efficacy.Results:DW532 inhibited EGFR and VEGFR2 in vitro kinase activity (the IC50 values were 4.9 and 5.5 μmol/L, respectively), and suppressed their downstream signaling. DW532 dose-dependently inhibited tubulin polymerization via direct binding to tubulin, thus disrupting the mitotic spindle assembly and leading to abnormal cell division. In a panel of human cancer cells, DW532 (1 and 10 μmol/L) induced G2/M phase arrest and cell apoptosis, which subsequently resulted in cytotoxicity. Knockdown of BubR1 or Mps1, the two core proteins of the spindle assembly checkpoint dramatically decreased DW532-induced cell cycle arrest in MDA-MB-468 cells. Moreover, treatment with DW532 potently and dose-dependently suppressed angiogenesis in vitro and in vivo.Conclusion:DW532 is a dual inhibitor against tubulin and tyrosine kinases, and deserves further development as a novel anti-cancer agent.

Discovery of a New Series of Naphthamides as Potent VEGFR-2 Kinase Inhibitors

Inhibition of VEGFR-2 signaling pathway has already become one of the most promising approaches for the treatment of cancer. In this study, we describe the design, synthesis, and biological evaluation of a new series of naphthamides as potent inhibitors of VEGFR-2. Among these compounds, 14c exhibited high VEGFR-2 inhibitory potency in both enzymatic and HUVEC cellular proliferation assays, with IC50 values of 1.5 and 0.9 nM, respectively. Kinase selectivity profiling revealed that 14c was a multitargeted inhibitor, and it also exhibited good potency against VEGFR-1, PDGFR-β, and RET. Furthermore, 14c effectively blocked tube formation of HUVEC at nanomolar level. Overall, 14c might be a promising candidate for the treatment of cancer.

DW10075, a novel selective and small-molecule inhibitor of VEGFR, exhibits antitumor activities both in vitro and in vivo

Aim:Targeting the VEGF/VEGF receptor (VEGFR) pathway has proved to be an effective antiangiogenic approach for cancer treatment. Here, we identified 6-((2-((3-acetamidophenyl)amino)pyrimidin-4-yl)oxy)-N-phenyl-1-naphthamide (designated herein as DW10075) as a novel and highly selective inhibitor of VEGFRs.Methods:In vitro tyrosine kinase activity was measured using ELISA, and intracellular signaling pathway proteins were detected by Western blot analysis. Endothelial cell proliferation was examined with CCK-8 assays, and tumor cell proliferation was determined with SRB assays. Cell migration, tube formation and rat aortic ring assays were used to detect antiangiogenic activity. Antitumor efficacy was further evaluated in U87-MG human glioblastoma xenograft tumors in nude mice receiving DW10075 (500 mg·kg−1·d−1, po) for two weeks.Results:Among a panel of 21 kinases tested, DW10075 selectively inhibited VEGFR-1, VEGFR-2 and VEGFR-3 (the IC50 values were 6.4, 0.69 and 5.5 nmol/L, respectively), but did not affect 18 other kinases including FGFR and PDGFR at 10 μmol/L. DW10075 significantly blocked VEGF-induced activation of VEGFR and its downstream signaling transduction in primary human umbilical vein endothelial cells (HUVECs), thus inhibited VEGF-induced HUVEC proliferation. DW10075 (1–100 nmol/L) dose-dependently inhibited VEGF-induced HUVEC migration and tube formation and suppressed angiogenesis in both the rat aortic ring model and the chicken chorioallantoic membrane model. Furthermore, DW10075 exhibited anti-proliferative activity against 22 different human cancer cell lines with IC50 values ranging from 2.2 μmol/L (for U87-MG human glioblastoma cells) to 22.2 μmol/L (for A375 melanoma cells). In U87-MG xenograft tumors in nude mice, oral administration of DW10075 significantly suppressed tumor growth, and reduced the expression of CD31 and Ki67 in the tumor tissues.Conclusion:DW10075 is a potent and highly selective inhibitor of VEGFR that deserves further development.

Establishment of platform for screening insulin-like growth factor-1 receptor inhibitors and evaluation of novel inhibitors

Aim:The insulin-like growth factor-1 receptor (IGF1R) is over-expressed in a wide variety of tumors and contributes to tumor cell proliferation, metastasis and drug resistance. The aim of this study was to establish a sensitive screening platform to identify novel IGF1R inhibitors.Methods:The catalytic domain of IGF1R was expressed using the Bac-to-Bac baculovirus expression system. The screening platform for IGF1R inhibitors was established based on ELISA. The binding profile of IGF1R with the inhibitors was predicted with molecular docking and then subjected to the surface plasmon resonance (SPR) approach. The growth inhibition of cancer cells by the inhibitors was assessed with MTT assay. Apoptosis was analyzed using flow cytometry and Western blotting.Results:A naturally occurring small molecule compound hematoxylin was identified as the most potent inhibitor (IC50 value=1.8±0.1 μmol/L) within a library of more than 200 compounds tested. Molecular simulation predicted the possible binding mode of hematoxylin with IGF1R. An SPR assay further confirmed that hematoxylin bound directly to IGF1R with high binding affinity (Kd=4.2×10-6 mol/L). In HL-60 cancer cells, hematoxylin inactivated the phosphorylation of IGF1R and downstream signaling and therefore suppressed cell proliferation. Mechanistic studies revealed that hematoxylin induced apoptosis in HL-60 cells via both extrinsic and intrinsic pathways.Conclusion:A simple, sensitive ELISA-based screening platform for identifying IGF1R inhibitors was established. Hematoxylin was identified as a promising IGF1R inhibitor with effective antitumor activity that deserves further investigation.