A naphthalimide-based peptide conjugate for concurrent imaging and apoptosis induction in cancer cells by utilizing endogenous hydrogen sulfide.

The excessive production of endogenous hydrogen sulfide (H 2 S) in cancer cells leads to enhanced tumor growth and metastasis. On the other hand, decreased endogenous H 2 S suppresses tumor growth. The reported approaches for inhibiting tumor growth are selective silencing of the tumor-promoting genes and pharmacological inhibition of these proteins. To enhance the antitumor efficacy of frontline chemotherapeutic agents, herein, we synthesized a highly sensitive endogenous H 2 S responsive fluorescent probe, i.e. , a hydrogen sulfide-sensing naphthalimide-based peptide conjugate (HSNPc), which showed selective inhibition of proliferation of cancer cells due to apoptosis induction. Furthermore, HSNPc suppressed the glycolytic reserve, a critical energy source for the proliferation of cancer cells. HSNPc also decreased the Young's modulus of HeLa cells compared to the control cells, which demonstrated a direct relation between cell apoptosis and cell stiffness. Taken together, we demonstrated the dual function of detection and killing of cancer cells by HSNPc that can be likened to a theranostic role.