Development of dihydropyrrolopyridinone-based PKN2/PRK2 chemical tools to enable drug discovery

The Protein Kinase N proteins (PKN1, PKN2 and PKN3) are Rho GTPase effectors. They are involved in several biological processes such as cytoskeleton organization, cell mobility, adhesion, and cell cycle. Recently PKNs have been reported as essential for survival in several tumor cell lines, including prostate and breast cancer. Here, we report the development of dihydropyrrolopyridinone-based inhibitors for PKN2 and its closest homologue, PKN1, and their associated structure–activity relationship (SAR). Our studies identified a range of molecules with high potency exemplified by compound 8 with Ki = 8 nM for PKN2 and 14x selectivity over PKN1. Membrane permeability and target engagement for PKN2 were assessed by a NanoBRET cellular assay. Importantly, good selectivity across the wider human kinome and other kinase family members was achieved. These compounds provide strong starting points for lead optimization to PKN1/2 development compounds

Development of pyridine-based inhibitors for the human vaccinia-related kinases 1 and 2

Vaccinia-related kinases 1 and 2 (VRK1 and VRK2) are human Ser/Thr protein kinases associated with increased cell division and neurological disorders. Nevertheless, the cellular functions of these proteins are not fully understood. Despite their therapeutic potential, there are no potent and specific inhibitors available for VRK1 or VRK2. We report here the discovery and elaboration of an aminopyridine scaffold as a basis for VRK1 and VRK2 inhibitors. The most potent compound for VRK1 (26) displayed an IC50 value of 150 nM and was fairly selective in a panel of 48 human kinases (selectivity score S(50%) of 0.04). Differences in compound binding mode and substituent preferences between the two VRKs were identified by the structure-activity relationship combined with the crystallographic analysis of key compounds. We expect our results to serve as a starting point for the design of more specific and potent inhibitors against each of the two VRKs10912661271CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP465651/2014-3; 400906/2014-788887.146077/2017-00; 88887.136342/2017-002013/50724-5; 2014/5087-0; 2016/25320-6; 2018/09475-5; 2018/03359-3This work was supported by the Brazilian agencies FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) (2013/50724-5 and 2014/5087-0), Embrapii (Empresa Brasileira de Pesquisa e Inovação Industrial), and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) (465651/2014-3 and 400906/2014-7). The SGC is a registered charity (number 1097737) that receives funds from AbbVie, Bayer Pharma AG, Boehringer Ingelheim, Canada Foundation for Innovation, Eshelman Institute for Innovation, Genome Canada, Innovative Medicines Initiative (EU/EFPIA) [ULTRA-DD grant no. 115766], Janssen, Merck KGaA Darmstadt Germany, MSD, Novartis Pharma AG, Ontario Ministry of Economic Development and Innovation, Pfizer, Takeda, and Wellcome [106169/ZZ14/Z]. R.A.M.S., S.N.S.V. and F.D.P. received FAPESP fellowships (2016/25320-6, 2018/09475-5 and 2018/03359-3 respectively). C.V.R. and A.S.S. received CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) postdoctoral fellowships (88887.146077/2017-00 and 88887.136342/2017-00, respectively