AD80, a multikinase inhibitor, targets RET, RAF, SRC, and S6K with significantly reduced activity on mTOR.

RET (V804L):0.6 nM, RET (V804M):0.4 nM

AD80 and AD81 effectively inhibit key signaling molecules (RET, RAF, SRC, S6K) with significantly diminished mTOR activity compared to AD57 and AD58. Specifically, AD80 stands out for its proficient inhibition of the Ras–Erk pathway, showcasing a well-balanced polypharmacological profile that targets Ret, Raf, Src, Tor, and S6K, yielding high efficacy with minimal toxicity. Furthermore, AD80 demonstrates potent anti-proliferative effects on MZ-CRC-1 and TT thyroid cancer cells in vitro, likely mediated by triggering apoptosis. Additionally, AD80 uniquely suppresses S6K1 in conjunction with inhibiting the TAM family tyrosine kinase AXL, preventing S6K1 phosphorylation and its association with mTOR. This leads to a sustained inhibition of S6K1-driven signaling and protein synthesis, underscoring its therapeutic potential.

AD80 significantly improves survival rates, rescuing 50% of mice transplanted with PTEN-deficient leukemia cells. When administered orally, both AD80 and AD81 remarkably allow 70-90% of Drosophila ptc>dRetMEN2B model animals to reach adulthood, surpassing the effectiveness of AD57. Furthermore, AD80 demonstrates superior tumor growth inhibition and minimizes body-weight fluctuations compared to vandetanib in a mouse xenograft model.

MZ-CRC-1 (MEN2B) and TT (MEN2A) cells are treated with AD80 (0.2 nM to 20 μM) for 7 days and cell viability is quantitated by MTT assay.

Mice showing established growing tumors are separated into vehicle or drug treatment groups. A similar range of tumor sizes is selected for each experiment (vehicle vs AD57; vehicle vs AD80 vs Vandetanib). Vehicle, AD57 (20 mg/kg), AD80 (30 mg/kg), or Vandetanib (50 mg/kg) are administered by oral gavage (PO; per os or by mouth) once daily, five times a week. Tumor and body weight measurements are performed 3 times a week.