Abstract
Purpose: :
To identify agents for the treatment of glaucoma, a collection of 6-aminoisoquinoline amides was screened against trabecular meshwork (TM) cell lines for the ability to induce reversible cell shape changes characteristic of compounds known to enhance TM outflow in vivo. The Structure-Activity Relationship (SAR) generated was used to synthesize compounds that are potent, reversible and resistant to amidase hydrolysis.
Methods: :
Porcine and human-derived trabecular meshwork cells were plated on fibronectin-coated multiwell plates 24 hours before testing. Cells were incubated with compounds for 6 hours, then fixed, stained and imaged on an InCell 1000. Compounds were also screened for a panel of kinase activities and the relationship between cells’ shape change and inhibition of kinases was profiled. To improve in vivo stability, an assay for resistance to amidase was developed. Compounds which met all success criteria in vitro were selected for further study.
Results: :
From the initial amides, AR-11236 (100 nM in the PTM assay) was found but it lacked appreciable solubility in PBS and was inactive in vivo. SAR analysis indicated 4 molecular regions that could be optimized. Moving or removing the adjacent aromatic ring from the amine improved water solubility, but decreased potency. Molecules in the AR-11771 series were soluble but not potent (1.7 mmHg decrease at 1%). Finally, moving the aliphatic or aromatic ring of AR-12080 to the alpha position resulted in molecules that were both soluble and potent. Hydrolytic stability of the initial leads was also poor. The stability of these compounds was enhanced by adding alkyl groups to the amine, as exemplified by AR-12162. The clinical candidate, AR-12286, possesses the optimized elements described above, as well as a superior in vivo profile.
Conclusions: :
A series of potent and hydrolytically-stable molecules was developed that reversibly alter cell shape in PTM and HTM cell lines and are nanomolar inhibitors of Rho kinase. AR-12286 was chosen as a clinical candidate for the treatment of glaucoma.
Keywords: signal transduction: pharmacology/physiology • intraocular pressure • outflow: trabecular meshwork