•Twenty-four indolin-2-one derivatives were synthesized.•All the compounds were screened for in vitro PAK4 inhibition assay.•Three of the compounds (11b, 12d, 12g) displayed promising enzymatic activity.•Compound 12g: Inducing apoptosis, G2/M phase arrest, Migration and Invasion inhibition by regulating PAK4-LIMK1-cofilin signalling pathway.•Docking and ADME profiling of 12g are reported.Utilizing a pharmacophore hybridization approach, a novel series of substituted indolin-2-one derivatives were designed, synthesized and evaluated for their in vitro biological activities against p21-activated kinase 4. Compounds 11b, 12d and 12g exhibited the most potent inhibitory activity against PAK4 (IC50 = 22 nM, 16 nM and 27 nM, respectively). Among them, compound 12g showed the highest antiproliferative activity against A549 cells (IC50 = 0.83 μM). Apoptosis analysis in A549 cells suggested that compound 12g delayed cell cycle progression by arresting cells in the G2/M phase of the cell cycle, retarding cell growth. Further investigation demonstrated that compound 12g strongly inhibited migration and invasion of A549 cells. Western blot analysis indicated that compound 12g potently inhibited the PAK4/LIMK1/cofilin signalling pathways. Finally, the binding mode between compound 12g with PAK4 was proposed by molecular docking. A preliminary ADME profile of the compound 12g was also drawn on the basis of QikProp predictions.Download high-res image (99KB)Download full-size image

A new series of novel 1-phenanthryl-tetrahydroisoquinoline derivatives were designed, synthesized and biologically evaluated for their PAK4 inhibitory activities and anti-proliferative effects against three cancer cell lines A549, MCF-7 and HT-1080. Among them, compound 12a exhibited the most potent inhibitory activity against PAK4 with an IC50 value of 0.42 μM. Moreover, this compound inhibited the invasion of A549 tumor cells by regulating the PAK4–LIMK1–cofilin signaling pathway in vitro, and exhibited anti-tumor activity in vivo in the A549 tumor xenograft model. To further evaluate the binding mode of 12a with PAK4, the biotinylated 12a derivative has been synthesized and it was used for immunoprecipitation assay. Intriguingly, our observations suggest that 12a interacts with both the N- and C-termini of PAK4.

Functional versatility and elevated expression in cancers have promoted p21-activated kinase 4 (PAK4) as one of the first-in-class anti-cancer drug targets. In this study, a series of novel 1-phenanthryl-tetrahydroisoquinoline analogues have been designed and synthesized as a novel class of small-molecule PAK4 inhibitors to fit into the cavity of PAK4. All of the target compounds were evaluated for their in vitro PAK4 inhibitory activities and antiproliferative activities. Lead optimization identified all the derivatives with more potency than the lead compound, especially compound 21a. Moreover, compound 21a significantly induced the cell cycle in the G1/S phase, and inhibited migration and invasion of MCF-7 cells via the regulation of the PAK4-LIMK1-cofilin signaling pathway. A molecular modeling study showed possible novel binding modes between 21a and PAK4 and provided a structural basis for further structure-guided design of PAK4 inhibitors.

To develop new CYP26A1 inhibitors, a three-cycle virtual screening was carried out based on the constructed homology model of human CYP26A1 using Dock, Fred, Gold and AutoDock. Twenty-two compounds exhibited high scores and reasonable binding modes in molecular docking were purchased from Specs Company. Eighteen compounds were tested their abilities to enhance ATRA-induced differentiation in human acute promyelocytic leukemia NB4 cells. Eight of them enhanced the ability of ATRA to induce differentiation at concentrations of 0.5 and 1 μM. Among these compounds, 2-(2-methylfuran-3-carboxamido)-3-phenylpropanoic acid (S8) is of most effective in blocking ATRA breaking down in NB4 cells based on the LC–MS/MS assay.

•Using KY04031 as a starting compound, a library of 2, 4-diaminoquinazoline derivatives were designed and synthesized.•The compounds potently suppressed the enzymatic activities of PAK4 with IC50 values in the 10−6-10−8 M range.•The most potent compound, 9d, inhibited PAK4 kinase activity with an IC50 value of 0.033 μM.•Compound 9d inhibited the PAK4-driven cell proliferation in a dose-dependent manner.•Compound 9d potently suppressed cancer cell migration and invasion by regulating PAK4- LIMK1 signalling pathway.Upon analysis of the reported crystal structure of PAK4 inhibitor KY04031 (PAK4 IC50 = 0.790 μM) in the active site of PAK4, we investigated the possibility of changing the triazine core of KY04031 to a quinazoline. Using KY04031 as a starting compound, a library of 2, 4-diaminoquinazoline derivatives were designed and synthesized. These compounds were evaluated for PAK4 inhibition, leading to the identification of compound 9d (PAK4 IC50 = 0.033 μM). Compound 9d significantly induced the cell cycle in the G1/S phase and inhibited migration and invasion of A549 cells that over-express PAK4 via regulation of the PAK4-LIMK1 signalling pathway. A docking study of compound 9d was performed to elucidate its possible binding modes and to provide a structural basis for further structure-guided design of PAK4 inhibitors. Compound 9d may serve as a lead compound for anticancer drug discovery and as a valuable research probe for further biological investigation of PAK4.In this work, based on a cyclization strategy and structure-guided SAR design, a series of 2,4-diaminoquinazoline derivatives were developed as a new class of PAK4 inhibitors.

Functional versatility and elevated expression in cancers have promoted p21-activated kinase 4 (PAK4) as one of the first-in-class anti-cancer drug targets. In this study, a series of novel 1-phenanthryl-tetrahydroisoquinoline analogues have been designed and synthesized as a novel class of small-molecule PAK4 inhibitors to fit into the cavity of PAK4. All of the target compounds were evaluated for their in vitro PAK4 inhibitory activities and antiproliferative activities. Lead optimization identified all the derivatives with more potency than the lead compound, especially compound 21a. Moreover, compound 21a significantly induced the cell cycle in the G1/S phase, and inhibited migration and invasion of MCF-7 cells via the regulation of the PAK4-LIMK1-cofilin signaling pathway. A molecular modeling study showed possible novel binding modes between 21a and PAK4 and provided a structural basis for further structure-guided design of PAK4 inhibitors.

A new series of novel 1-phenanthryl-tetrahydroisoquinoline derivatives were designed, synthesized and biologically evaluated for their PAK4 inhibitory activities and anti-proliferative effects against three cancer cell lines A549, MCF-7 and HT-1080. Among them, compound 12a exhibited the most potent inhibitory activity against PAK4 with an IC50 value of 0.42 μM. Moreover, this compound inhibited the invasion of A549 tumor cells by regulating the PAK4–LIMK1–cofilin signaling pathway in vitro, and exhibited anti-tumor activity in vivo in the A549 tumor xenograft model. To further evaluate the binding mode of 12a with PAK4, the biotinylated 12a derivative has been synthesized and it was used for immunoprecipitation assay. Intriguingly, our observations suggest that 12a interacts with both the N- and C-termini of PAK4.