Abstract Sarcomas have limited systemic options beyond cytotoxic chemotherapy. VEGFR-directed multi-kinase inhibitors such as regorafenib provide modest benefit, but their broad RTK inhibition constrains the therapeutic margin. Because VEGFR2 and TIE2 are central regulators of tumor angiogenesis and vascular stability, we hypothesized that selective dual VEGFR2/TIE2 inhibition would improve potency while reducing off-target toxicity. We applied fragment recombination of validated RTK inhibitor scaffolds, combined with dual VEGFR2/TIE2 docking and phenotypic screening, to design candidate inhibitors with an improved potency-selectivity balance for sarcoma therapy. We computationally designed ∼300 dual VEGFR2/TIE2 candidates via fragment recombination and synthesized 15 prioritized by docking and binding-site analyses. Antiproliferative activity was evaluated by MTS assay at 24 and 48 h (2.5-10 µM) in human osteosarcoma lines (143B, MG63, KHOS/NP, U-2 OS) and murine macrophages (RAW264.7) to assess myeloid cell toxicity. Lead compounds were compared with pazopanib, regorafenib, and sorafenib. At 2.5 µM (48 h), pazopanib, regorafenib, and sorafenib maintained ≥100% viability across all sarcoma lines. At 10 µM, pazopanib and regorafenib showed ≥80% viability, while sorafenib reduced 143B viability to 55% but spared other lines (≥80%). Among synthesized candidates, SMC-101-008 and SMC-101-011 showed early activity at 2.5 µM, reducing 143B and MG63 viability to 57-65% (24 h) and 47-84% (48 h). However, at 10 µM (48 h), both compounds also ablated RAW264.7 (1% viability), indicating loss of selectivity at higher doses. In contrast, SMC-101-017 exhibited time- and dose-dependent sarcoma-selective activity. At 2.5 µM, minimal activity was observed at 24 h (≥88% viability), but by 48 h, KHOS/NP and 143B viability dropped to 39% and 19%, respectively, while RAW264.7 remained unaffected (100%). At 10 µM, SMC-101-017 showed moderate early suppression (66-72% viability across all lines at 24 h) but selectively eliminated KHOS/NP and 143B by 48 h (25% and 7%, respectively) while preserving RAW264.7 viability (100%) SMC-101-017 demonstrated potent, time-dependent cytotoxicity against osteosarcoma while sparing myeloid cells across a 4-fold dose range, distinguishing it from approved multi-kinase TKIs. These findings nominate SMC-101-017 for target validation and in vivo evaluation, and support fragment-based design for developing kinase inhibitors with improved therapeutic windows. Citation Format: Youngkeun Lee, Bo Kyoung Kim, Ji-yoon Choi, Min-jeong Kim, Sung Wook Seo, . Fragment-recombination design of a dual VEGFR2/TIE2 inhibitor with sarcoma-selective cytotoxicity abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5881.
Lee et al. (Fri,) studied this question.