Hydrogen-bubbled platinum-colloid suppresses human esophagus- or tongue-carcinoma cells with intracellular platinum-uptake and the diminished normal-cell mortality.

Carcinostatic effects of combined use of hydrogen nano-bubbles (nano-H) and platinum-povidone (PVP--Pt) were examined. Hydrogen-dissolved medium was prepared by hydrogen-gas bubbling with a microporous gas-emittance-terminal into a medium in the absence or presence of PVP-Pt (nano-H, nano-H/PVP-Pt). Human esophagus-derived carcinoma cells KYSE70 were repressed for cell proliferation with nano-H/PVP-Pt more markedly than with nano-H, indicating the hydrogen-intensification for PVP-Pt-alone-carcinostasis. However, the intensified carcinostasis required co-administration of nano-H and PVP-Pt, and no intensified carcinostasis was shown in two-step separate administration of nano-H and PVP-Pt. Furthermore, hydrogen bubbling into PVP-Pt-containing medium achieved more appreciable carcinostasis than mere addition of PVP-Pt into nano-H-containing medium, indicating the potent interaction of hydrogen and PVP-Pt. The nano-H/PVP-Pt-administered human tongue-derived carcinoma cells HSC-4 were repressed for cell proliferation more markedly than pre-malignant human tongue-derived epitheliocytes DOK, concurrently with more abundant intracellular Pt-intake into HSC-4 cells than DOK as analyzed by ICP-MS. Thus, PVP-Pt is able to adsorb hydrogen nano-bubbles on Pt and applicable for cancer therapy by diminishing the side-effects to normal cells.