Removing a Cystein Group On Interferon Alpha 2b at Position 2 and 99 does Not Diminish Antitumor Activity of the Protein, Even Better.

Interferon alpha 2b is the only standard therapeutic protein for hepatitis virus infections. Further study demonstrated that this protein also posseses antitumor activity in several cancerous organs. One main pathway of this antitumor activity is mediated through antiproliferation as well as proapoptotic effects. Previously, we have successfully developed recombinant human interferon alpha 2b (rhIFNα2b) by using a synthetic gene. In addition, two mutein forms of rhIFNα2b were generated to improve the characteristics of this protein. Two point mutations showed better pharmacokinetic profiles than one point mutation as well as the native form. In the present study, this mutein form was studied for ist antitumor effect in vitro using HepG2 cells. As a comparison, the native form as well as a commercial rIFNα2b were used. Several parameters were investigated including the MTT assay, cell viability test, cell cycle using flow cytometric analysis, and the genes and protein expressions involved in cell growth. The latest was observed to study the mechanism of rhIFNα2b. There was no significant difference in the MTT assay and cell viability after cells were treated with both forms of rhIFNα2b. However, the mutein rhIFNα2b tended to show better proapoptotic activity reflected by flow cytometric data, protein expression of pSTAT1, and DNA expression of caspase 3.