A novel tumor-anchored fluorescent probe for imaging HClO in cuproptosis and pyroptosis models

Compared to normal cells, nitroreductase (NTR) and hypochlorous acid (HClO) are both highly expressed in hypoxic tumors. Therefore, NTR and HClO can be used as tumor cell markers for the diagnosis and treatment of tumors. The tumor-anchored fluorescent probe by the reduction property of NTR for imaging HClO was then designed and synthesized. The probe was consisted of three components, fluorophore was based on 3-hydroxyphthalimide dye, N , N -dimethyl thiocarbamate was chosen as the recognition group for HClO, and 2-nitroimidazole was selected as the hypoxic tumor-anchored moiety by its reduction reaction with NTR. When detecting HClO, the probe showed a good linear response in the range of 0-10 μM, a low detection limit of 0.22 μM, high selectivity and sensitivity. Moreover, the probe could monitor exogenous and endogenous HClO in living cells. The probe successfully distinguished tumor cells from normal cells by its outstanding tumor-targeted ability. Furthermore, the probe was successfully employed for imaging HClO in cuproptosis and pyroptosis models. It was of significance for elucidating the physiological mechanisms involved in development of tumor cells during cuproptosis and pyroptosis. All these results proved that the probe was a useful analytical tool for detecting HClO in tumor image.