Identification of isatin-triazole-benzenesulfonamide hybrids as dual hCA IX/XII and c-met inhibitors with hypoxia-mediated chemo-sensitizing activity

One of the main factors contributing to treatment resistance and a poor prognosis in colorectal cancer is hypoxia. Eleven isatin-based hybrids comprising 1,2,3-triazole and benzenesulfonamide fragments (5a-f and 7a-e) were logically designed and synthesized in this study to investigate their dual inhibitory potential against carbonic anhydrases IX and XII (CA IX/XII) and receptor tyrosine kinase c-Met, two hypoxia-related targets. Strong nanomolar inhibition of CA IX/XII and sub-micromolar to low-micromolar inhibition of c-Met were shown by a number of drugs (5c, 5d, 5e, 5f, and 7e). Compound 5d had the highest activity (IC₅₀ = 1.57 μM under hypoxia vs. 9.57 μM under normoxia), according to a subsequent cytotoxicity assay in HCT-116 colorectal cancer cells, which showed improved potency of all lead compounds under hypoxic conditions. In the cell lines HT-29 and SW-620, the better profile of 5d was further validated. Mechanistic investigations revealed that 5d triggered apoptosis and caused G₂/M phase arrest, confirming its function in hypoxia-driven cytotoxicity. Additionally, in hypoxic conditions, 5d significantly increased the effectiveness of 5-fluorouracil (5-FU) and oxaliplatin (OXP), increasing its potency by more than 10 times. Positive pharmacokinetic and drug-like characteristics were validated through in silico ADME profiling. Molecular docking investigations revealed that 5d exhibited strong binding interactions within the c-Met and CA IX/XII active sites. Compound 5d could be a promising dual-targeting option for overcoming hypoxia-associated resistance in colorectal cancer, as indicated by these data.