Hollow mesoporous organosilica nanotheranostics incorporating formimidoyltransferase cyclodeaminase (FTCD) plasmids for magnetic resonance imaging and tetrahydrofolate metabolism fission on hepatocellular carcinoma

The formimidoyltransferase cyclodeaminase (FTCD) gene encodes an enzyme required for the catabolism of histidine and tetrahydrofolate (THF). Previous studies showed that FTCD plays a role as a tumour suppressor gene in hepatocellular carcinoma (HCC). It is unknown whether the restoration of functional FTCD may exhibit an anti-tumour effect on HCC. This study constructed a delivery system based on hollow mesoporous organosilica nanotheranostics (HMON) capable of efficiently loading Mn ions and FTCD plasmids. This study showed that the Mn-doped and FTCD-loaded nanoparticles (HMON@Mn-PEI@FTCD) could efficiently induce the expression of FTCD and achieve enhanced magnetic resonance imaging. In vitro results demonstrated that the upregulation of FTCD induced by HMON@Mn-PEI@FTCD nanoparticles dramatically reduced intracellular THF levels, inhibited of NADPH/NADP+ and GSH/GSSG ratios, and induced reactive oxygen species generation and mitochondrial oxidative stress. As a result, cytochrome c release increased with the opening of the mitochondrial permeability transition pore, which finally activated the caspase-dependent cell apoptosis pathway. Therefore, our designed HMON@Mn-PEI@FTCD could induce apoptosis by activating the mitochondria-mediated apoptosis signalling pathway, and finally significantly suppressed the proliferation of HCC both in vitro and in vivo, which provides an effective strategy for the treatment of HCC.