Myeloid-resident neuropilin-1 promotes choroidal neovascularization while mitigating inflammation.

Age-related macular degeneration (AMD) in its various forms is a leading cause of blindness in industrialized countries. Here, we provide evidence that ligands for neuropilin-1 (NRP1), such as Semaphorin 3A and VEGF-A, are elevated in the vitreous of patients with AMD at times of active choroidal neovascularization (CNV). We further demonstrate that NRP1-expressing myeloid cells promote and maintain CNV.

Identification of a Novel Series of Potent TrkA Receptor Tyrosine Kinase Inhibitors.

A novel series of N-(3-(6-substituted-aminopyridin-3-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting TrkA receptor tyrosine kinase was identified. SAR study of the series allowed us to design and synthesize compounds possessing inhibitory activity of TrkA kinase enzyme in the low nanomolar range with low residual activity against c-Met and with no significant activity against VEGFR2.

Identification of a novel series of potent RON receptor tyrosine kinase inhibitors.

A novel series of N-(3-fluoro-4-(2-substituted-thieno[3,2-b]pyridin-7-yloxy)phenyl)-1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxamides targeting RON receptor tyrosine kinase was designed and synthesized. SAR study of the series allowed us to identify compounds possessing either inhibitory activity of RON kinase enzyme in the low nanomolar range with low residual activity against the closely related c-Met or potent dual inhibitory activity against RON and c-Met, with no significant activity against VEGFR2 in both cases.

Identification of potent and selective VEGFR receptor tyrosine kinase inhibitors having new amide isostere headgroups.

A novel series of malonamide-type dual VEGFR2/c-Met inhibitors in which one of the amide bonds was replaced by an amide isostere-a trifluoroethylamine unit, was designed, synthesized, and evaluated for their enzymatic and cellular inhibition of VEGFR2 and c-Met enzymes. Optimization of these molecular entities resulted in identification of potent and selective inhibitors of VEGFR2 enzyme.

N3-arylmalonamides: a new series of thieno[3,2-b]pyridine based inhibitors of c-Met and VEGFR2 tyrosine kinases.

A family of thieno[3,2-b]pyridine based small molecule inhibitors of c-Met and VEGFR2 were designed based on lead structure 2. These compounds were shown to have IC(50) values in the low nanomolar range in vitro and were efficacious in human tumor xenograft models in mice in vivo.

N-(4-(6,7-Disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: a novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors.

A series of N-(4-(6,7-disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC(50) values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.

N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: a novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors.

A series of N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC(50) values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.

Discovery of a novel and potent series of thieno[3,2-b]pyridine-based inhibitors of c-Met and VEGFR2 tyrosine kinases.

A series of thieno[3,2-b]pyridine-based inhibitors of c-Met and VEGFR2 tyrosine kinases is described. The compounds demonstrated potency with IC(50) values in the low nanomolar range in vitro while the lead compound also showed in vivo activity against various human tumor xenograft models in mice. Further exploration of this class of compounds is underway.

Overcoming resistance to interferon-induced apoptosis of renal carcinoma and melanoma cells by DNA demethylation.

Epigenetic editing of gene expression by aberrant methylation of DNA may help tumor cells escape attack from the innate and acquired immune systems. Resistance to antiproliferative effects and apoptosis induction by interferons (IFNs) was postulated to result from silencing of IFN response genes by promoter hypermethylation. Treatment of human ACHN renal cell carcinoma (RCC) and A375 melanoma cells with the DNA demethylating nucleoside analog 5-AZA-2'-deoxycytidine (5-AZA-dC) synergistically augmented antiproliferative effects of IFN- alpha (alpha) 2 and IFN-beta (beta).

Expression of RASSF1A, an epigenetically silenced tumor suppressor, overcomes resistance to apoptosis induction by interferons.

Resistance of human renal cell carcinoma (RCC) and melanoma to the apoptosis-inducing effects of IFNs was postulated to result from epigenetic silencing of genes by DNA methylation, a common feature of human cancers. To reverse silencing, 5-AZA-deoxycytidine (5-AZA-dC) or selective depletion of DNA methyltransferase 1 (DNMT1) by phosphorothioate oligonucleotide antisense (DNMT1 AS) were employed in cells resistant (<5% terminal deoxynucleotidyl transferase-mediated nick-end labeling positive) to apoptosis induction by IFN-alpha2 and IFN-beta (ACHN, SK-RC-45, and A375). 5-AZA-dC and DNMT1 AS similarly depleted available DNMT1 protein and, at doses that did not cause apoptosis alone, resulted in apoptotic response to IFNs.

Release of methyl CpG binding proteins and histone deacetylase 1 from the Estrogen receptor alpha (ER) promoter upon reactivation in ER-negative human breast cancer cells.

Estrogen receptor alpha (ER) is an epigenetically regulated gene. Inhibitors of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) synergistically activate the methylated ER gene promoter in ER-negative MDA-MB-231 human breast cancer cells. Chromatin immunoprecipitation was used to examine the chromatin status and repressor complex associated with silenced ER and changes in the key regulatory factors during reactivation by inhibitors of DNMT (5-aza-2'-deoxycytidine) and HDAC (trichostatin A).

DNMT1 is required to maintain CpG methylation and aberrant gene silencing in human cancer cells.

Transcriptional silencing by CpG island methylation is a prevalent mechanism of tumor-suppressor gene suppression in cancers. Genetic experiments have defined the importance of the DNA methyltransferase Dnmt1 for the maintenance of methylation in mouse cells and its role in neoplasia. In human bladder cancer cells, selective depletion of DNMT1 with antisense inhibitors has been shown to induce demethylation and reactivation of the silenced tumor-suppressor gene CDKN2A.

An essential role for DNA methyltransferase DNMT3B in cancer cell survival.

Abnormal methylation and associated silencing of tumor suppressor genes is a common feature of many types of cancers. The observation of persistent methylation in human cancer cells lacking the maintenance methyltransferase DNMT1 suggests the involvement of other DNA methyltransferases in gene silencing in cancer. To test this hypothesis, we have evaluated methylation and gene expression in cancer cells specifically depleted of DNMT3A or DNMT3B, de novo methyltransferases that are expressed in adult tissues.