Bioprocess optimization of interferon beta-1-a in Pichia pastoris and its improved inhibitory effect against hepatocellular carcinoma cells

Abstract

Interferon-beta-1a (INF-beta-1a) has gained significant attention due to its emerging applications in the treatment of different human diseases. Therefore, many researchers have attempted to produce it in large quantities and also in a biologically active form using different expression systems. In the present study, we aimed to improve the expression level of INF-beta-1a by Pichia pastoris using optimization of culture onditions. The codon-optimized INF-beta-1a gene was cloned into pPICZ alpha A plasmid under the control of alcohol oxidase I (AOX1) promoter. The protein expression was induced using different concentrations of methanol at different pHs and temperatures. The biological activity of produced protein was evaluated by anti-proliferative assay. The ideal culture conditions for the expression of INF-beta-1a by P. pastoris were found to be induction with 2 methanol at pH 7.0 culture medium at 30 C which yielded a concentration of 15.5 mg/L INF-beta-1a in a shake flask. Our results indicate that differences in glycosylation pattern could result in different biological activities as INF alpha-1a produced by P. pastoris could significantly more reduce the cell viability of HepG-2 cells, a hepatocellular carcinoma cell line, than a commercially available form of this protein produced by CHO.