There is increasing evidence that tumor-associated macrophages promote the malignancy of some cancers. Colonystimulating factor-1 (CSF-1) is expressed by many tumors and is a growth factor for macrophages and mediates osteoclast differentiation. Herein, we report the efficacy of a novel orally active CSF-1 receptor (CSF-1R) kinase inhibitor, JNJ-28312141, in proof of concept studies of solid tumor growth and tumor-induced bone erosion. H460 lung adenocarcinoma cells did not express CSF-1R and were not growth inhibited by JNJ-28312141 in vitro. Nevertheless, daily p.o. administration of JNJ-28312141 caused dose-dependent suppression of H460 tumor growth in nude mice that correlated with marked reductions in F4/ 80 + tumor-associated macrophages and with increased plasma CSF-1, a possible biomarker of CSF-1R inhibition. Furthermore, the tumor microvasculature was reduced in JNJ-28312141-treated mice, consistent with a role for macrophages in tumor angiogenesis. In separate studies, JNJ-28312141 was compared with zoledronate in a model in which MRMT-1 mammary carcinoma cells inoculated into the tibias of rats led to severe cortical and trabecular bone lesions. Both agents reduced tumor growth and preserved bone. However, JNJ-28312141 reduced the number of tumor-associated osteoclasts superior to zoledronate. JNJ-28312141 exhibited additional activity against FMS-related receptor tyrosine kinase-3 (FLT3). To more fully define the therapeutic potential of this new agent, JNJ-28312141 was evaluated in a FLT3-dependent acute myeloid leukemia tumor xenograft model and caused tumor regression. In summary, this novel CSF-1R/FLT3 inhibitor represents a new agent with potential therapeutic activity in acute myeloid leukemia and in settings where CSF-1-dependent macrophages and osteoclasts contribute to tumor growth and skeletal events.
We have developed a novel series of potent and selective factor Xa inhibitors that employ a key 7-fluoroindazolyl moiety. The 7-fluoro group on the indazole scaffold replaces the carbonyl group of an amide that is found in previously reported factor Xa inhibitors. The structure of a factor Xa cocrystal containing 7-fluoroindazole 51a showed the 7-fluoro atom hydrogen-bonding with the N-H of Gly216 (2.9 A) in the peptide backbone. Thus, the 7-fluoroindazolyl moiety not only occupied the same space as the carbonyl group of an amide found in prior factor Xa inhibitors but also maintained a hydrogen bond interaction with the protein's beta-sheet domain. The structure-activity relationship for this series was consistent with this finding, as the factor Xa inhibitory potencies were about 60-fold greater (DeltaDelta G approximately 2.4 kcal/mol) for the 7-fluoroindazoles 25a and 25c versus the corresponding indazoles 25b and 25d. Highly convergent synthesis of these factor Xa inhibitors is also described.
A novel series of potent and selective alpha(v)beta(3)/alpha(v)beta(5) dual( )()inhibitors was designed, synthesized, and evaluated against several integrins. These compounds were synthesized through a Mitsunobu reaction between the guanidinium mimetics and the corresponding central templates. Guanidinium mimetics with enhaced rigidity (i.e., (2-pyridylamino)propoxy versus the 2-(6-methylamino-2-pyridyl)ethoxy) led to improved activity toward alpha(v)beta(3). Exemplary oral bioavailability in mice was achieved using the indole central scaffold. Although, oral bioavailability was maintained when the indole molecular core was replace with the bioisosteric benzofuran or benzothiophene ring systems, it was found to not significantly impact the integrin activity or selectivity. However, the indole series displayed the best in vivo pharmacokinetic properties. Thus, the indole series was selected for further structure-activity relationships to obtain more potent alpha(v)beta(3)/alpha(v)beta(5) dual antagonist with improved oral bioavailability.
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