The Arabian camel, Camelus dromedarius interferon epsilon: Functional expression, in vitro refolding, purification and cytotoxicity on breast cancer cell lines

Abstract

The current study highlights, for the first time, cloning, overexpression and purification of the novel interferon epsilon (IFNƐ), from the Arabian camel Camelus dromedaries. The study then assesses the cytotoxicity of IFNε against two human breast cancer cell lines MDA-MB-231 and MCF-7. Full-length cDNA encoding interferon epsilon (IFNε) was isolated and cloned from the liver of the Arabian camel, C . dromedarius using reverse transcription-polymerase chain reaction. The sequence analysis of the camel IFNε cDNA showed a 582-bp open reading frame encoding a protein of 193 amino acids with an estimated molecular weight of 21.230 kDa. A BLAST search analysis revealed that the C . dromedarius IFNε shared high sequence identity with the IFN genes of other species, such as Camelus ferus , Vicugna pacos , and Homo sapiens . Expression of the camel IFNε cDNA in Escherichia coli gave a fusion protein band of 24.97 kDa after induction with either isopropyl β-D-1-thiogalactopyranoside or lactose for 5 h. Recombinant IFNε protein was overexpressed in the form of inclusion bodies that were easily solubilized and refolded using SDS and KCl. The solubilized inclusion bodies were purified to apparent homogeneity using nickel affinity chromatography. We examined the effect of IFNε on two breast cancer cell lines MDA-MB-231 and MCF-7. In both cell lines, IFNε inhibited cell survival in a dose dependent manner as observed by MTT assay, morphological changes and apoptosis assay. Caspase-3 expression level was found to be increased in MDA-MB-231 treated cells as compared to untreated cells.

Recent Advances in Camel Immunology

“…The camel displays a similar broad spectrum of IFN alpha family members as cattle ( 142 ) and humans ( 143 ). For instance, eleven IFN-α subtypes ( 144 ) and one member of the IFN epsilon family were identified ( 145 ). The functional properties of type I interferons appear similar to other mammalian species, including the antiviral effect, the induction of interferon-responsive genes, and the tumor cell cytotoxicity ( 144 , 145 ).…”

“…For instance, eleven IFN-α subtypes ( 144 ) and one member of the IFN epsilon family were identified ( 145 ). The functional properties of type I interferons appear similar to other mammalian species, including the antiviral effect, the induction of interferon-responsive genes, and the tumor cell cytotoxicity ( 144 , 145 ). Studies describing other immune-modulatory effects of type I interferons are still lacking ( 145 ).…”

Isolation and characterization of the mink interferon-epsilon gene and its antiviral activity

“…Recombinant human IFNε can induce the production of an antiviral protein, MxA, to exhibit antiviral effects and inhibit human immunodeficiency virus replication (20). Recombinant IFN-ε from cattle, camels, dogs, and sheep has also shown significant antiviral activity (21)(22)(23)(24). Although IFN-α and IFN-β preparations have good antiviral effects, their long-term use may lead to side effects such as mental anxiety and depression.…”