Therapeutic Efficacy and Inhibitory Mechanism of Regorafenib Combined with Radiation in Colorectal Cancer

Abstract

Background: Although both chemotherapy and radiotherapy (RT) can sufficiently maintain tumor suppression of colorectal cancer (CRC), these treatments may trigger the expression of nuclear factor kappa B (NF-ĸB) and compromise patients’ survival. Regorafenib suppresses NF-ĸB activity in various tumor types. However, whether regorafenib may act as a suitable radiosensitizer to enhance therapeutic efficacy of RT remains unknown. Materials and Methods: Here, we established a CRC-bearing animal model to investigate the therapeutic efficacy of regorafenib in combination with RT, through measurement of tumor growth, body weight, whole-body computed tomography (CT) scan and immunohisto-chemistry staining. Results: Smallest tumor size and weight were found in the combination treatment group. In addition, RT-induced up-regulation of NF-ĸB and downstream proteins were diminished by regorafenib. Moreover, the body weight and liver pathology in the treated group were similar to those of the non-treated control group. Conclusion: Regorafenib may enhance the anti-CRC efficacy of RT.