Biomedical effect of 125I-AFPasON in HCC evaluated with Raman spectra

Objectives To explore the interference effect of the AFP gene with the antisense oligonucleotide (asON) labeled with radioiodine-125 (125I-AFP asON) in hepatic cellular carcinoma (HCC) using the laser Raman spectra technique.

Methods The 125I-AFP asON-Chitosan nanoparticles were prepared simply by mixing the radio labeled asON and Chitosan phosphonate. The nanoparticle complexes with 74 or 296kBq/μl 125I-AFP asON were transfected into the HepG2 cell for 24 hours, then the damage of DNA and protein in cells was determined using the confocal Raman scattering microscope and the expression of the AFP gene and protein was observed also.

Results The transfect efficiency of the 125I-AFPasON mediated by the chitosan nanoparticles in HepG2 cells is 52.5%, which is twice of naked AFPasONs. After the Chitosan nanoparticles with 125I-AFPasON were transfered into the HepG2 cell for 24 hours. The characteristic Raman spectra indicated the discrimination of the structure and conformation of the AFP DNA after the different radiation of 125I-AFPasON (Fig.1). On the other hand, the characteristic Raman spectra of the protein damage were detected in the HepG2 cell, and it is interesting that the Raman spectra of the damaged ascorbic acid were also observed, which might be related to the harm of the target protein. The results of AFP PCR and western blotting showed that the AFP gene expression was depressed down by the 125I-AFPasON than that of the naked AFPasON, and the AFP protein was also decreased in HepG2 cells.

Conclusions The technique of Raman spectra is a valuable to detect the biomedical effect in cell radiated by radioactive iodine-125, and the nanoparticle-mediated 125I-AFPasON may enhance the interference efficient of the AFP gene depression