The intermolecular interaction between naringin (NAR) and bovine serum albumin (BSA) was studied by fluorescence spectrum and microcalorimetry. The theoretical model of the interaction between NAR and BSA was established. Δ H, Δ S and Δ G were obtained by using the isothermal titration microcalorimetric technique and Gibbs-Helmholtz equation. The Fōrster equation was used to analyze the critical distance between NAR and BSA in the UV-fluorescence spectra. Based on spectroscopy- and microcalorimetry-assisted analysis, the theoretical model of the interaction between NAR and BSA was established. The critical distance between NAR and BSA was 2.06 nm, which indicated that the interaction between NAR and BSA was short-range intermolecular interaction. The results showed that the thermodynamic parameters Δ H <0, Δ S> 0 and Δ G <0 between NAR and BSA molecules have been successfully established by microcalorimetry. These microcalorimetry results showed that the interaction between NAR and BSA was spontaneous exothermic molecule interaction. According to the Ross theory analysis of NAR and BSA, intermolecular forces are mainly hydrophobic and electrostatic forces. Based on the analysis of UV-fluorescence spectra to obtain the binding distance, the intermolecular interactions between NAR and BSA were short-range. The theoretical model results showed that the intermolecular interaction of NAR and BSA occurred mainly in the domain IIA region of BSA. The NAR and BSA intermolecular forces are mainly electrostatic forces. Both van der Waals force and the presence of hydrogen bonds and the intermolecular interaction between BSA and NAR were a spontaneous process. The experimental results are basically consistent with the theoretical modeling results. These data can provide a useful reference for a comprehensive understanding of the intermolecular interactions between biological macromolecules and flavonoids and the study of microscopic pharmacological mechanisms.
Ubiquitin-conjugating enzyme E2C (UBE2C) is closely related to the proliferation of various tumor cells, but its relationship with the occurrence and development of lung cancer is not clear. The roles of UBE2C in cellular proliferation, cell senescence and migration of A549 lung cancer cells were elucidated by RT-PCR, Western blotting, immunofluorescence, SA-β-Gal cell senescence staining, cell scratch and Trans-well assays. Transient over-expression or targeted silencing of UBE2C by gene modification technique was used. The results showed that the expression of UBE2C in lung cancer cells was significantly higher than that in normal cells. The levels of UBE2C mRNA and protein were significantly increased by 3.5-fold or decreased by 0.5-fold in A549 cells after transient over-expression or silence of UBE2C, leading to significant promotion or inhibition of cell proliferation, thereby reducing or increasing the rate of apoptosis. In addition, over-expression of UBE2C significantly inhibited cell senescence, whereas silence of UBE2C promoted cell senescence. Moreover, UBE2C significantly affected the mRNA and protein expression of metastasis related genes E-cadherin and vimentin, and further modulated cell migration. This study provided information for the roles of UBE2C in the development and progression of lung cancer.