Novel (2E,4E,6Z)-7-(2-alkoxy-3,5-dialkylbenzene)-3-methylocta-2,4,6-trienoic acid retinoid X receptor modulators are active in models of type 2 diabetes

Previous data have shown that RXR-selective agonists (e.g., 3 and 4) are insulin sensitizers in rodent models of non-insulin-dependent diabetes mellitus (NIDDM). Unfortunately, they also produce dramatic increases in triglycerides and profound suppression of the thyroid hormone axis. Here we describe the design and synthesis of new RXR modulators that retain the insulin-sensitizing activity of RXR agonists but produce substantially reduced side effects. These molecules bind selectively and with high affinity to RXR and, unlike RXR agonists, do not activate RXR homodimers. To further evaluate the antidiabetic activity of these RXR modulators, we have designed a concise and systematic structure-activity relationship around the 2E,4E,6Z-7-aryl-3-methylocta-2,4,6-trienoic acid scaffold. Selected compounds have been evaluated using insulin-resistant rodents (db/db mice) to characterize effects on glucose homeostasis. Our studies demonstrate the effectiveness of RXR modulators in lowering plasma glucose in the db/db mouse model.

Antiangiogenic and antitumor effects of a protein kinase Cbeta inhibitor in murine lewis lung carcinoma and human Calu-6 non-small-cell lung carcinoma xenografts

In cell culture, the compound 317615.2HCl, a potent inhibitor of VEGF-stimulated HUVEC proliferation, was not very effective against Calu-6 non-small-cell lung carcinoma cells (IC50 26 microM). Exposure to combinations of paclitaxel or carboplatin and 317615.2HCl with Calu-6 cells in culture resulted in cell survival that reflected less-than-additivity to additivity of the two agents. Administration of 317615.2HCl orally twice daily to nude mice bearing subcutaneous Calu-6 tumors resulted in a decreased number of intratumoral vessels as determined by CD31 and CD105 staining to 50% of the number in control tumors. 317615.2HCl showed antitumor activity against the Lewis lung carcinoma and increased the tumor growth delay produced by paclitaxel by 5-fold, that produced by gemcitabine by 2-fold and that produced by carboplatin by 1.7-fold. There was a decrease in the number of lung metastases in the Lewis lung carcinoma that paralleled the increased response of the primary tumor with each treatment combination. Administration of 317615.2HCl also increased the tumor growth delay produced by fractionated radiation therapy in the Lewis lung tumor. Treatment with 317615.2HCl was an effective therapy in the Calu-6 non-small-cell lung carcinoma xenograft when the compound was administered early (days 4-18) or later (days 14-30). Combination treatment regimens in which 317615.2HCl was administered along with or sequentially with paclitaxel or carboplatin were much more effective than the chemotherapeutic agents administered alone. 317615.2HCl is in early clinical testing.

Antiangiogenic and antitumor effects of a protein kinase Cbeta inhibitor in human HT-29 colon carcinoma and human CaKi1 renal cell carcinoma xenografts

The compound 317615 x 2HCl, a selective protein kinase Cbeta inhibitor, was not very cytotoxic toward human CaKi1 renal cell carcinoma cells or human HT-29 colon carcinoma cells in monolayer culture. Isobologram analysis was used to determine additivity or synergy of the combination regimens. Exposure of CaKi1 cells to 317615 x 2HCl (10 or 100 mM) along with gemcitabine or 5-fluorouracil for 24 hours resulted in cytotoxicity that appeared to be less-than-additive to additive for the two agents. Exposure of HT-29 cells to gemcitabine along with 317615 x 2HCl (10 mM or 100 mM) resulted in a synergistic cytotoxicity while combinations with 5-fluorouracil resulted in additive to greater-than-additive cytotoxicity for the agents. After treatment of CaKi1 or HT-29 xenograft-bearing mice with 317615 x 2HCl, immunohistochemical staining for expression of endothelial specific markers, either CD31 or CD105, was used to quantify the number of intratumoral vessels in the samples. CaKi1 tumor angiogenesis was very responsive to treatment with 317615 x 2HCl such that the number of intratumoral vessels stained by CD31 or CD105 was decreased to 20% of the control. The HT-29 colon carcinoma angiogenesis was also responsive to 317615 x 2HCl, such that the number of intratumoral vessels stained by CD31 or CD105 was decreased to 40% to 50% of the controL 5-fluorouracil, cisplatin or fractionated radiation therapy was combined with treatment with 317615 x 2HCl in the simultaneous combination treatment regimen in animals bearing HT-29 colon carcinoma xenografts. The resulting tumor growth delays indicated that administration of 317615 x 2HCl increased the effects of the cytotoxic therapy. Both a simultaneous or an overlapping treatment regimen and a sequential treatment regimen were used to assess 317615 x 2HCl alone and along with fractionated radiation therapy or gemcitabine against the human CaKi1 renal cell carcinoma xenograft. The CaKi1 tumor was quite sensitive to fractionated radiation therapy and to gemcitabine and, although 317615 x 2HCl was an effective single agent in this tumor, the combination regimens did not reach additivity for the combination regimens in vivo. 317615 x 2HCl is in early clinical testing.

Synthesis of novel retinoid X receptor-selective retinoids

Retinoids 1-5 have been identified as potent RXR agonists for evaluation in the treatment of non-insulin-dependent (type II) diabetes mellitus (NIDDM). Highly convergent syntheses of 1-5 have been developed. The core tetrahydronaphthalene 7, employed in the synthesis of 1 and 2, was prepared in 98% yield using an AlCl(3)-catalyzed (0.03 equiv) Friedel-Crafts alkylation of toluene with 2,5-dichloro-2,5-dimethylhexane 6. A nitromethane-mediated Fridel-Crafts acylation of 7 with chloromethylnicotinate 9 was developed to prepare ketone 10 in 68% yield. Chelate-controlled addition of MeMgCl to 10 followed by dehydration afforded olefin 11 in 65% yield. Cyclopropanation of 11 with trimethylsulfoxonium ylide, followed by saponification, completed a five-step synthesis of 1 in 33% yield. FeCl(3)-catalyzed (0.05 equiv) Friedel-Crafts acylation of 7 with chloromethylterephthalate 14 afforded ketone 15 in 81% yield. Saponification of 15 and reaction with 50% aqueous NH(2)OH in AcOH afforded a 9:1 mixture of cis and trans oximes, from which the desired cis-oxime 2 was isolated in 43% yield. The core bromo-dihydronaphthalene 29 required for the synthesis of 3-5 was prepared by a Shapiro reaction. Transmetalation of 29 and reaction with Weinreb amides 30b or 36 afforded ketones 32 and 37, which were converted into 3-5 using chemistry comparable to the tetrahydronaphthylene series. Suzuki coupling of boronic acids 41 and 42 with vinyl triflate 43 provided an alternative approach to the synthesis of this class of compounds.

Design and synthesis of 2-methyl-2-[4-(2-[5-methyl-2-aryloxazol-4-yl]ethoxy)phenoxy]propionic acids: a new class of dual PPARalpha/gamma agonists

Propionic acid derivative 8, which was designed and synthesized based on putative pharmacophores of known PPARgamma- and PPARalpha-selective compounds, exhibits potent dual PPARalpha/gamma agonist activity as demonstrated by in vitro binding and dose overlap in the newly introduced EOB mouse model for glucose lowering and lipid/cholesterol homeostasis.

Antiangiogenic and antitumor effects of a protein kinase C beta inhibitor in human hepatocellular and gastric cancer xenografts

Hepatocellular carcinoma and gastric cancer are the most prevalent tumors worldwide. Hep3B hepatocellular carcinoma and HS746T gastric cancer were used as models for these diseases in culture and in vivo. The PKC beta inhibitor 317615.2HCl was not very cytotoxic toward HS746T or Hep3B cells in culture and was, in the main, additive in cytotoxicity with cisplatin, 5-fluorouracil and gemcitabine when cell in monolayer were exposed to these agents in combination with 317615.2HCl. Treatment of nude mice bearing HS746T or Hep3B xenografts with 317615.2HCl orally twice daily resulted in a small decreased in CD31-stainable intratumoral vessels in the HS746T tumors and 60% decrease in CD31-stainable vessels in the Hep3B tumors. Somewhat larger decreases were observed in the vessel stained with CD105. As a single agent 317615.2HCl produced tumor growth delays between 6.5 and 15 days in the HS746T xenograft and between 5 and 25 days in the Hep3B xenograft over the dosage range (3 to 30 mg/kg). Sequential and simultaneous combinations with 317615.2HCl and 5-fluorouracil and gemcitabine resulted in increases in tumor growth delay on both schedules. Gemcitabine produced a 15-day tumor growth delay of the HS746T gastric carcinoma that was increased to 40 days when combined simultaneously with 317615.2HCl and to 30 days with the sequential treatment regimen. 5-Fluorouracil produced a 9-day tumor growth delay of the Hep3B hepatocellular carcinoma that increased to 31 days by simultaneous treatment with 317615.2HCl and to 43 days with the sequential treatment regimen. Treatment with the protein kinase C beta inhibitor 317615.2HCl decreased HS746T and Hep3B angiogenesis and improved treatment outcome with 5-fluorouracil and gemcitabine.

Cyclization strategies for the synthesis of macrocyclic bisindolylmaleimides

Three new approaches to the synthesis of macrocyclic bisindolylmaleimides 1-4 have been identified. Two strategies afford 8, the penultimate intermediate for the synthesis of 1-4, in 73% and 32% yield by intramolecular cyclization of 31 and 40, respectively. The optimum synthesis of 1 was achieved in nine steps and 15% yield by intramolecular formation of the macrocycle and maleimide in one step by reaction of the sodium indolate of 12 with methyl indole-3-glyoxylate 47. The mechanism of this reaction has been elucidated, using the trityl-protected derivative, to involve initial formation of the tricarbonyl imide 48, followed by irreversible alkylation of the indole nitrogen to generate the 17-membered macrocycle 49. Cyclization of 49 to hydroxymaleimide 50 and subsequent dehydration afforded 8a. This approach eliminated the problem of dimerization observed in the intramolecular cyclization reactions.

Salt form selection and characterization of LY333531 mesylate monohydrate

LY333531 is a potent protein kinase C(beta) (PKC(beta)) inhibitor currently under development for the treatment of diabetic complications. Seven salts of LY333531 (hydrochloride, sulfate, mesylate, succinate, tartrate, acetate and phosphate) were evaluated during the early phase of development. Physical property screening techniques including microscopy, DSC, TGA, XRPD, hygroscopicity and solubility were utilized to narrow the selection to two salts: the mesylate and hydrochloride. Identification of the optimal salt form was based upon solubility, bioavailability, physical stability and purity. During the evaluation process three hydrated forms (anhydrate, monohydrate, and tetrahydrate) of the hydrochloride salt were identified. The mesylate salt was found to give only one, a monohydrate. Processing parameters (e.g. filtration rate, crystal form stability) demonstrated that the anhydrate was the preferred form of the hydrochloride salt. Bioavailability studies in dogs indicated that the C(max) and area under the plasma concentration vs. time curve (AUC) for LY333531 and its active metabolite, LY338522, following administration of the mesylate salt were approximately 2.6 times those obtained after the LY333531 HCl dose. This difference was presumed to be due primarily to the fact that the mesylate was five times more soluble than the hydrochloride salt in water. These factors led to selection and development of LY333531 mesylate monohydrate as the active pharmaceutical ingredient for clinical evaluation.

(S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16, 21-dimetheno-1H, 13H-dibenzo[e,k]pyrrolo[3,4-h][1,4,13]oxadiazacyclohexadecene-1,3(2H)-d ione (LY333531) and related analogues: isozyme selective inhibitors of protein kinase C beta

Protein kinase C (PKC) is a family of closely related serine and threonine kinases. Overactivation of some PKC isozymes has been postulated to occur in several diseases states, including diabetic complications. Selective inhibition of overactivated PKC isozymes may offer a unique therapeutic approach to disease states such as diabetic retinopathy. A novel series of 14-membered macrocycles containing a N-N'-bridged bisindolylmaleimide moiety is described. A panel of eight cloned human PKC isozymes (alpha, beta I, beta II, gamma, delta, epsilon, sigma, eta) was used to identify the series and optimize the structure and associated activity relationship. The dimethylamine analogue LY333531 (1), (S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16, 21-dimetheno-1H, 13H-dibenzo[e,k]pyrrolo[3,4-h][1,4,13]oxadiazacyclohexadecene++ +-1,3(2H)-dione, inhibits the PKC beta I (IC50 = 4.7 nM) and PKC beta II (IC50 = 5.9 nM) isozymes and was 76- and 61-fold selective for inhibition of PKC beta I and PKC beta II in comparison to PKC alpha, respectively. The additional analogues described in the series are also selective inhibitors of PKC beta. LY333531 (1) exhibits ATP dependent competitive inhibition of PKC beta I and is selective for PKC in comparison to other ATP dependent kinases (protein kinase A, calcium calmodulin, caesin kinase, src tyrosine kinase). The cellular activity of the series was assessed using bovine retinal capillary endothelial cells. Retinal endothelial cell dysfunction has been implicated in the development of diabetic retinopathy. Plasminogen activator activity stimulated by a phorbol ester (4 beta-phorbol 12,13-dibutyrate) in endothelial cells was inhibited by the compounds in the series with ED50 values ranging from 7.5 to 0.21 microM. A comparison of the PKC isozyme and related ATP dependent kinase inhibition profiles is provided for the series and compared to the profile for staurosporine, a nonselective PKC inhibitor. The cellular activity of the series is compared with that of the kinase inhibitor staurosporine.