Synthesis of vitamin–selenium complex and its effects on proteins and tumor cells

A selenium–vitamin P complex (SEVP) was synthesized and its structure was determined by IR, LC–MS and 1H NMR. Its biological effects on bovine serum albumin (BSA) and human colon carcinoma tumor cells were studied by molecular spectra, MTT and flow cytometry. The interaction of SEVP and BSA was discussed by fluorescence quenching method and Förster non-radiation energy transfer theory. The thermodynamic parameters ΔHθ, ΔGθ, ΔSθ at different temperatures were calculated and the results indicate the interaction is an exothermic as well as entropy-driven process. Hydrogen bond and electrostatic force played major role in the reaction. The binding geometry and conformation changes of BSA were investigated by fluorescence probe technique and circular dichroism (CD) spectra. The effects of SEVP on human colon carcinoma tumor cells HT29 were tested by MTT method and flow cytometry (FCM). The MTT results show the proliferation of HT29 tumor cells were inhibited by SEVP and the inhibition was associated with dose and time. The FCM analysis disclosed SEVP interrupted the DNA synthesis of tumor cells at S phase.

Graphical abstractThe circular dichroism results exhibited a decrease of α-helical structures from 62.3% to 53.9% at molar ratio of 10:1 (SEVP/BSA), which indicated that the synthesized Se complex can bound with the amino acid residues on the main polypeptide chain and thus can be carried by serum albumin in human body.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A selenium–vitamin P complex (SEVP) was synthesized and characterized. ► The binding details and energy transfer between SEVP and BSA were investigated. ► The proliferation of HT29 tumor cells is inhibited by SEVP. ► SEVP can interrupt the DNA synthesis of tumor cells at S phase.