Discovery of LY2457546: a multi-targeted anti-angiogenic kinase inhibitor with a novel spectrum of activity and exquisite potency in the acute myelogenous leukemia-Flt-3-internal tandem duplication mutant human tumor xenograft model.

LY2457546 is a potent and orally bioavailable inhibitor of multiple receptor tyrosine kinases involved in angiogenic and tumorigenic signalling. In biochemical and cellular assays, LY2457546 demonstrates potent activity against targets that include VEGFR2 (KDR), PDGFRß, FLT-3, Tie-2 and members of the Eph family of receptors. With activities against both Tie2 and Eph receptors, LY2457546 possesses an activity profile that distinguishes it from multikinase inhibitors. When compared head to head with sunitinib, LY2457546 was more potent for inhibition of endothelial tube formation in an in vitro angiogenesis co-culture model with an intermittent treatment design. In vivo, LY2457546 inhibited VEGF-driven autophosphorylation of lung KDR in the mouse and rat in a dose and concentration dependent manner. LY2457546 was well tolerated and exhibited efficacy in a 13762 syngeneic rat mammary tumor model in both once and twice daily continuous dosing schedules and in mouse human tumor xenograft models of lung, colon, and prostate origin. Additionally, LY2457546 caused complete regression of well-established tumors in an acute myelogenous leukemia (AML) FLT3-ITD mutant xenograft tumor model. The observed efficacy that was displayed by LY2457546 in the AML FLT3-ITD mutant tumor model was superior to sunitinib when both were evaluated using equivalent doses normalized to in vivo inhibition of pKDR in mouse lung. LY2457546 was well tolerated in non-clinical toxicology studies conducted in rats and dogs. The majority of the toxicities observed were similar to those observed with other multi-targeted anti-angiogenic kinase inhibitors (MAKs) and included bone marrow hypocellularity, hair and skin depigmentation, cartilage dysplasia and lymphoid organ degeneration and necrosis. Thus, the unique spectrum of target activity, potent in vivo anti-tumor efficacy in a variety of rodent and human solid tumor models, exquisite potency against a clinically relevant model of AML, and non-clinical safety profile justify the advancement of LY2457546 into clinical testing.

Acyl sulfonamide anti-proliferatives. Part 2: activity of heterocyclic sulfonamide derivatives.

The anti-proliferative activity of acylated heterocyclic sulfonamides is described in Vascular Endothelial Growth Factor-dependent Human Umbilical Vascular Endothelial Cells (VEGF-HUVEC) and in HCT116 tumor cells in a soft agar diffusion assay.

Acyl sulfonamide anti-proliferatives: benzene substituent structure-activity relationships for a novel class of antitumor agents.

Two closely related diaryl acylsulfonamides were recently reported as potent antitumor agents against a broad spectrum of human tumor xenografts (colon, lung, breast, ovary, and prostate) in nude mice. Especially intriguing was their activity against colorectal cancer xenografts. In this paper, rapid parallel synthesis along with traditional medicinal chemistry techniques were used to quickly delineate the structure-activity relationships of the substitution patterns in both phenyl rings of the acylsufonamide anti-proliferative scaffold. Although the molecular target of the compounds remains unclear, we determined that the vascular endothelial growth factor-dependent human umbilical vein endothelial cells assay in combination with a soft agar disk diffusion assay allowed for optimization of potency in the series. The pharmacokinetic properties and in vivo activity in an HCT116 xenograft model are reported for representative compounds.

Preparation of novel aza-1,7-annulated indoles and their conversion to potent indolocarbazole kinase inhibitors.

The synthesis of novel aza-1,7-annulated indoles was achieved and these were converted to indolocarbazoles that proved to be potent kinase inhibitors. These compounds were also evaluated in a human colon carcinoma cell line and proved to be good antiproliferative agents.

Synthesis of 1,7-annulated indoles and their applications in the studies of cyclin dependent kinase inhibitors.

The synthesis of a novel series of 1,7-annulated indolocarbazoles 2 and 16 is described. These compounds were found to be potent cyclin dependent kinase inhibitors with good antiproliferative activity against two human carcinoma cell lines. These inhibitors also arrested tumor cells at the G1 phase and inhibited pRb phosphorylation.

1,7-annulated indolocarbazoles as cyclin-dependent kinase inhibitors.

The synthesis and kinase inhibitory activity of a series of novel 1,7-annulated indolocarbazoles 6 and 16 is described. These compounds exhibited potent inhibitory activity against cyclin-dependent kinase 4 and good antiproliferative activity in a human colon carcinoma cell line.

Properties of bisphosphonates in the 13762 rat mammary carcinoma model of tumor-induced bone resorption.

Bone metastasis from primary tumors is a clinically important complication of neoplastic progression. The role of parathyroid hormone-related protein (PTHrP) and transforming growth factor (TGF)-beta1 in this process has been clearly established. The current study describes an in vivo model of 13762 rat mammary carcinoma tumor cell-induced osteolysis in which PTHrP and TGF-beta1 expression is observed. Exposure of in vitro-cultured 13762 cells to doxorubicin, cis-platinum, carboplatin, methotrexate, 5-fluorouracil, paclitaxel, alendronate, risedronate, or pamidronate for 72 h resulted in varying effects on cell proliferation (IC(50) values of 0.005, 0.4, 1.9, >40, 17.9, 0.003, >40, >40, and 33.6 micro M, respectively). Tumor cells were implanted into the intramedullary space of the proximal tibia of rats, and the time course of tumor progression was evaluated using radiographic and microcomputed tomography scanning techniques. Trabecular bone mineral density, cortical bone mineral density, and whole bone mineral density were measured (in mg/cm(3)). In untreated animals, radiographic evidence of osteolysis was evident 7 days after implantation. Trabecular bone mineral density and whole bone mineral density were significantly decreased by 21 days after implantation (48% and 26%, respectively). Bisphosphonates showed broad protective activity against tumor-driven osteolysis, Immunohistochemical evaluation of s.c. and intratibially implanted cells demonstrated the expression of PTHrP and TGF-beta1. The results of this study demonstrate the ability of 13762 rat mammary carcinoma cells to elicit a measurable osteolysis and that bisphosphonates inhibit the tumor-induced bone resorption in this model.

Aryl[a]pyrrolo[3,4-c]carbazoles as selective cyclin D1-CDK4 inhibitors.

The synthesis of new analogues of Arcyriaflavin A in which one indole ring is replaced by an aryl or heteroaryl ring is described. These new series of aryl[a]pyrrolo[3,4-c]carbazoles were evaluated as inhibitors of Cyclin D1-CDK4. A potent and selective D1-CDK4 inhibitor, 7a (D1-CDK4 IC(50)=45 nM), has been identified. The potency, selectivity profile against other kinases, and structure-activity relationship (SAR) trends of this class of compounds are discussed.

Studies on cyclin-dependent kinase inhibitors: indolo-[2,3-a]pyrrolo[3,4-c]carbazoles versus bis-indolylmaleimides.

A series of indolo[2,3-a]pyrrolo[3,4-c]carbazoles and their bis-indolylmaleimides precursors have been prepared in order to compare their activity as D1-CDK4 inhibitors. Both enzymatic and antiproliferative assays have shown that the structurally more constrained indolo[2,3-a]pyrrolo[3,4-c]carbazoles are consistently more active (8-42-fold) in head-to-head comparison with their bis-indolylmaleimides counterparts. Cell-cycle analysis using flow cytometry have also shown that the indolocarbazoles are selective G1 blockers while the bis-indolylmaleimides arrest cells in the G2/M phase.

Novel, potent and selective cyclin D1/CDK4 inhibitors: indolo[6,7-a]pyrrolo[3,4-c]carbazoles.

The synthesis and CDK inhibitory properties of a series of indolo[6,7-a]pyrrolo[3,4-c]carbazoles is reported. In addition to their potent CDK activity, the compounds display antiproliferative activity against two human cancer cell lines. These inhibitors also effect strong G1 arrest in these cell lines and inhibit Rb phosphorylation at Ser780 consistent with inhibition of cyclin D1/CDK4.

Synthesis, structure-activity relationship, and biological studies of indolocarbazoles as potent cyclin D1-CDK4 inhibitors.

Novel substituted indolocarbazoles were synthesized, and their kinase inhibitory capability was evaluated in vitro. 6-Substituted indolocarbazoles 4 were found to be potent and selective D1/CDK4 inhibitors. 4d and 4h exhibited potent and ATP-competitive D1/CDK4 activities with IC50 values of 76 and 42 nM, respectively. Both compounds had high selectivity against the other kinases. These D1/CDK4 inhibitors inhibited tumor cell growth, arrested tumor cells at the G1 phase, and inhibited pRb phosphorylation.

Synthesis of quinolinyl/isoquinolinyl[a]pyrrolo [3,4-c] carbazoles as cyclin D1/CDK4 inhibitors.

A novel series of pyrrolo[3,4-c] carbazoles fused with a quinolinyl/isoquinolinyl moiety were synthesized and their D1/CDK4 inhibitory and antiproliferative activity were evaluated. Compound 8H, 14H-isoquinolinyl[6,5-a]-pyrrolo[3,4-c]carbazole-7,9-dione (1d) was found to be a highly potent D1/CDK4 inhibitor with an IC(50) of 69 nM. Compound 1d also inhibited tumor cell growth, arrested tumor cells in G1 phase and inhibited pRb phosphorylation.

Antiangiogenic effects of a protein kinase Cbeta-selective small molecule.

BACKGROUND: Protein kinase C frequently plays a central role in the intracellular signal transduction of growth factors and cytokines. METHODS: The acyclic bisindolylmaleimide 317615 x 2HCl was identified as a potent selective inhibitor of protein kinase Cbeta. The compound 317615 x 2HCl was tested in culture and in vivo in the rat corneal micropocket and in the SW2 small-cell lung carcinoma human tumor xenograft. RESULTS: In cell culture, 317615 x 2HCl was a more potent inhibitor of VEGF-stimulated HUVEC proliferation (IC50 150 nM, 72 h) than of human SW2 small-cell lung carcinoma cell proliferation (IC50 3.5 microM, 72 h). When administered orally twice daily for 10 days, the compound 317615 x 2HCl markedly decreased the neoangiogenesis induced by VEGF or bFGF in the rat corneal micropocket assay. To assess antitumor efficacy, 317615 x 2HCl was administered orally twice daily to nude mice bearing SW2 xenograft tumors on days 14 through 30 after tumor implantation. The number of countable intratumoral vessels was decreased in a dose-dependent manner reaching as low as one-quarter the number in the control tumors. The decrease in intratumoral vessels was paralleled by increases in tumor growth delay. Treatment of the tumor-bearing animals with paclitaxel or carboplatin followed by treatment with 317615 x 2HCl resulted in a 2.5- to 3.0-fold increase in tumor growth delay compared with the standard chemotherapeutic agents alone. CONCLUSIONS: 317615 x 2HCl represents a new approach to antiangiogenic therapy in cancer-blocking multiple growth factor signaling pathways in endothelial cells with a single agent. 317615 x HCl is in early clinical testing.