TSL2109 is an orally active and selective inhibitor of DYRK2 and CDK4/6, with an IC50 value of 22 nM for DYRK2 and over 93% kinase selectivity. In vitro, TSL2109 induces cell cycle arrest and promotes apoptosis (apoptosis). It effectively overcomes Enzalutamide resistance by inhibiting tumor growth both in vivo and in vitro. Additionally, TSL2109 demonstrates resistance to cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. It shows good safety and is applicable for research in prostate and breast cancer [1][2].

TSL2109 exhibits potent antiproliferative activity in DU145 prostate cancer cells, with an IC50 of 0.933 μM, and inhibits cell growth in a dose-dependent manner after treatment for 72 hours to 5 days. It induces G1 cell cycle arrest and apoptosis after 24-hour exposure in DU145 cells. Additionally, TSL2109 significantly suppresses proliferation and induces G1 cell cycle arrest and apoptosis in 22Rv1 cells. It effectively inhibits E2F target gene pathways and G2/M checkpoint pathways in both DU145 and 22Rv1 cells, while also upregulating apoptotic and P53 pathways in DU145 cells. In Enzalutamide-resistant prostate cancer organoid models (PDOs) (PR6513B), TSL2109 demonstrates strong growth inhibitory effects after 7 days of treatment at 50 or 100 μM. Furthermore, it markedly inhibits the proliferation of androgen receptor (AR) inhibitor-resistant prostate cancer cells and organoids. TSL2109 reduces the expression of phosphorylated retinoblastoma protein (p-RB), phosphorylated 4E binding protein 1 (p-4E-BP1), and B-cell lymphoma 2 (BCL2), and significantly suppresses E2F signaling and G2/M phase-related signaling pathways.

TSL2109, when administered orally via gavage at doses of 100-200 mg/kg daily for 45 days, demonstrated favorable safety in a DU145 mouse xenograft tumor model. At a higher dose of 1000 mg/kg as a single oral gavage, TSL2109 exhibited excellent tolerance and safety without adverse behavioral effects in the same model. Furthermore, TSL2109 at 75 mg/kg administered daily for 21 days showed potential to overcome Enzalutamide resistance and potentially enhance its efficacy. In a mouse PDX model resistant to Enzalutamide, daily administration of TSL2109 at 100 mg/kg for 30 days demonstrated its potential to counteract Enzalutamide resistance. Additionally, TSL2109 effectively inhibited tumor growth in a prostate cancer PDX model resistant to AR inhibitorsand exhibited strong activity in a breast cancer model resistant to CDK4/6 inhibitors.