KHS-101

Radiotherapy plays an increasingly crucial role in the treatment of hepatocellular carcinoma (HCC). However, resistance to radiotherapy remains a significant obstacle to achieving optimal treatment outcomes. Our objective is to elucidate the mechanisms underlying radiotherapy resistance. Through proteomic sequencing of radiotherapy-resistant cell lines and patient-derived xenograft tissues from HCC patients, we identified that Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) is upregulated in both radiotherapy-resistant cell lines and tissues. After radiotherapy treatment, DNAPK phosphorylates TACC3 at 315 threonine, leading to enhanced protein stability of TACC3. TACC3 facilitated the proliferative capacity and radiotherapy resistance of HCC cells by promoting the interaction between XRCC5 and XRCC6 through specific residues within its coiled-coil domain, namely ILE736, ASN742 and GLU773. This interaction facilitates DNA damage repair via the non-homologous end joining pathway in response to radiation, thereby contributing to the radiotherapy resistance in HCC cells. Furthermore, TACC3 increases the production of IL-4 and IL-10 within HCC cells, inducing the differentiation of M0 macrophages to M2 macrophages within the immune microenvironment, leading to the suppression of CD8⁺T cell cytotoxic functions and creating an immunosuppressive microenvironment in HCC. Targeting TACC3 with inhibitor KHS101 significantly inhibit the proliferation of HCC and improve the immune microenvironment of HCC.

Transforming acidic coiled coil containing protein 3 (TACC3) is emerging as an attractive anticancer target in recent years, however, few TACC3 small-molecular inhibitors have been reported up to now. In this study, fifteen compounds were designed and synthesized based on the lead compound KHS101 to find more potent TACC3 inhibitors. Among them, the most potent compound 7g exhibited about 10-folds more potent antiproliferative activities than KHS101 in various cancer cell lines. Two different protein-drug binding assays including DARTS, and CETSA revealed TACC3 as a biologically relevant target of compound 7g. In addition, compound 7g induced cell cycle arrest at the G2/M phase and induced cell apoptosis. Furthermore, compound 7g depolarized the MMP and induced ROS generation in a dose-dependent manner in U87 cells. More importantly, 7g reduced tumor weight by 72.7% in U87 xenograft model at a dose of 20 mg/kg/day without obvious toxicity. Altogether, compound 7g deserved further investigations as a novel, safe and efficacious TACC3 inhibitor for the treatment of GBM.