Carbon nanoparticles-Fe(II) complex for efficient theranostics of xenografted colonic tumor

Abstract Background Overwhelming Fe accumulation in tumor arouses strong oxidative stress. To benefit the cancer patients, Fe(II) delivered by carbon nanoparticles-Fe(II) complex (CNSI-Fe) should be visualized to ensure the successful intratumoral injection and the antitumor mechanisms should be investigated at molecular level. Results Intracellular Fe accumulations associating with the uptakes of CNSI-Fe were observed both in vitro and in vivo. The retention of Fe(II) in tumor over 72 h was visualized by magnetic resonance imaging. CNSI-Fe inhibited the tumor growth and expanded the lifespan of colonic tumor-bearing mice. The antitumor activity of CNSI-Fe was attributed to the increases of OH radicals and the oxidative stress in tumor cells, which resulted in cell apoptosis and ferroptosis. The transcriptome analyses confirmed the changes of ferroptosis and inflammation signaling pathways by CNSI-Fe treatment. The low toxicity of CNSI-Fe was indicated by the serum biochemistry, hematology, and histopathology. Conclusion CNSI-Fe induced the efficient apoptosis and ferroptosis of colonic tumor for cancer therapy. Our results would benefit the clinical applications of CNSI-Fe and stimulate great interest in the nanomedicine.