Expression, Purification and Functional Assessment of Smallest Isoform of Human Interleukin-24 in Escherichia coli

• Main Authors: Samira Valiyari, Reza Mahdian, Mona Salami, Mana Oloomi, Maryam Golshani, Mohammad Ali Shokrgozar, Saeid Bouzari
• Format: Article
• Language: English
• Published: Instituto de Tecnologia do Paraná (Tecpar) 2017-08-01
• Series: Brazilian Archives of Biology and Technology
• Subjects: Smallest isoform of IL-24; Thioredoxin; Recombinant production; Anti-cancer agent
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132017000100307&lng=en&tlng=en

ABSTRACT Interleukin-24 (IL-24) is a novel tumor-suppressor gene that has different alternative splice isoforms. It has been shown that new smallest isoform of human IL-24 gene, lacking three exons, induces higher levels of cytotoxicity than all the isoforms, indicating shortest isoform of IL-24 may be a new promising anti-cancer agent. In this study, we aimed to provide a reproducible method for recombinant production of the smallest isoform of IL-24 (sIL-24). The Structure of sIL-24 was analyzed using bioinformatics tools (I-TASSER, Prosa, RAMPAGE and SPDBV version 4.1). The DNA sequence encoding sIL-24 was chemically synthesized and sub-cloned into the pET-32a (+) vector for further protein expression in Escherichia coli BL21 (DE3) strain. Upon IPTG induction, sIL-24 peptide was expressed as a thioredoxin fusion protein. The recombinant sIL-24 was released from the fusion by TEV protease cleavage followed by nickel affinity chromatography. The yield of the purified sIL-24 was estimated about 380 μg/ml. MTT assay showed that sIL-24 peptide inhibited the proliferation of PC-3 cancer cells more effectively than full length IL-24 protein, while none affect the survival of MRC-5 normal cells. These results indicate that the presented expression system is an efficient system for the production of small functional recombinant sIL-24 peptide.This functional peptide may have cancer therapeutic application.