Expression and characterization of recombinant human epidermal growth factor receptor antigene (HER-2) as an indicator of breast cancer in yeast fermented systems

Immunotherapy has been practiced for more than two decades in the treatment of cancer. In this method, monoclonal antibodies bind to tumor specific antigens and inhibit their function. Therefore, scientists are looking for special targets on cancer cells that can be differentiate cancer cells from normal cells. In some cancers, including breast cancer human epidermal growth factor receptor-2 (HER-2) is significantly higher than the normal level. The goal for this project was to obtain expression with high quality of HER-2 with high activity in yeast expression system and its use in future studies.
In order to express the extracellular domain of the HER-2 receptor we have used pPICZα and Pichia pastoris wild type X33 as a sequence vector and host cell respectively. Expression of HER-2 was analyzed using Sodium Dodecyl Sulfate Poly Acrylamide Gel Electrophoresis 7% and accuracy of expression was confirmed by ELISA.
The expression of Her-2 antigen was evaluated by 7% SDS-PAGE with 185 KDa protein ladder. The results indicated that the expression of Her-2 antigen has been increased by IPTG induction. Moreover, the activity of Her-2 antigen was studied by ELISA technique using commercial anti Her-2 monoclonal antibody (Herceptin) and Her-2 antigen has shown high affinity to Herceptin.
In this study, we have produced the Her-2 antigen in yeast expression system. With regards to yeast expression system advantages including secretory expression, protein folding, protein glycosylation, and activity of expressed protein in a wide range of pH, the Her-2 antigen which expressed in yeast host has great quality and will be used in future studies