Comparative Study of Sonodynamic and Photoactivated Cancer Therapies with Re(I)-Tricarbonyl Complexes Comprising Phenanthroline Ligands

Herein, we have compared the effectivity of light-based
photoactivated
cancer therapy and ultrasound-based sonodynamic therapy with Re(I)-tricarbonyl
complexes (Re1–Re3) against cancer
cells. The observed photophysical and TD-DFT calculations indicated
the potential of Re1–Re3 to act as
good anticancer agents under visible light/ultrasound exposure. Re1 did not display any dark- or light- or ultrasound-triggered
anticancer activity. However, Re2 and Re3 displayed concentration-dependent anticancer activity upon light
and ultrasound exposure. Interestingly, Re3 produced 1O2 and OH• on light/ultrasound
exposure. Moreover, Re3 induced NADH photo-oxidation
in PBS and produced H2O2. To the best of our
knowledge, NADH photo-oxidation has been achieved here with the Re(I)
complex for the first time in PBS. Additionally, Re3 released
CO upon light/ultrasound exposure. The cell death mechanism revealed
that Re3 produced an apoptotic cell death response in
HeLa cells via ROS generation. Interestingly, Re3 showed
slightly better anticancer activity under light exposure compared
to ultrasound exposure.