C-Met Inhibitor MK-8003 Radiosensitizes c-Met-Expressing Non-Small-Cell Lung Cancer Cells With Radiation-Induced c-Met-Expression
Menée sur des lignées cellulaires de cancer du poumon non à petites cellules, cette étude montre qu'un inhibiteur de l'expression de c-Met, un récepteur à activité tyrosine kinase, sensibilise aux rayonnements ionisants les cellules tumorales exprimant ce récepteur
Introduction: The radiation doses used to treat unresectable lung cancer are often limited by the proximity of normal tissues. Overexpression of c-Met, a receptor tyrosine kinase occurs in about half of non-small-cell lung cancers (NSCLCs) and has been associated with resistance to radiation therapy and poor patient survival. We hypothesized that inhibiting c-Met would increase the sensitivity of NSCLC cells to radiation, enhancing the therapeutic ratio, which may potentially translate into improved local control. Methods: We tested the radiosensitivity of two high-c-Met-expressing NSCLC lines, EBC-1 and H1993, and two low-c-Met-expressing lines, A549 and H460, with and without the small-molecule c-Met inhibitor MK-8033. Proliferation and protein expression were measured with clonogenic survival assays and Western blotting, respectively. [gamma]-H2AX levels were evaluated by immunofluorescence staining. Results: MK-8033 radiosensitized the high-c-Met-expressing EBC-1 and H1993 cells but not the low-c-Met-expressing cell lines A549 and H460. However, irradiation of A549 and H460 cells increased the expression of c-Met protein at 30 minutes after the irradiation. Subsequent targeting of this up-regulated c-Met by using MK-8033 followed by a second radiation dose reduced the clonogenic survival of both A549 and H460 cells. MK-8033 reduced the levels of radiation-induced phosphorylated (activated) c-Met in A549 cells. Conclusions: These results suggest that inhibition of c-Met could be an effective strategy to radiosensitize NSCLC tumors with high basal c-Met expression or tumors that acquired resistance to radiation because of up-regulation of c-Met. (C) 2012International Association for the Study of Lung Cancer