Synthesis, Cytotoxic Properties and Effects on Early and Late Gene Induction of a Chimeric Diphtheria Toxin‐Leukemia‐Inhibitory Factor Protein

Abstract

Leukemia-inhibitory factor (LIF) is a neuropoietin able to regulate the differentiation and the survival of many cell types, which include some neuronal populations. The present study describes the genetic construction, expression, purification and properties of a diphtheria-toxin-related LIF gene fusion in which the native receptor-binding domain of diphtheria toxin was replaced with a gene encoding human LIE The fusion protein expressed from the chimeric tox gene was designated DT-(1-389)-LIF-(2-184)-peptide. This fusion protein has a deduced molecular mass of 65980 Da and is formed by fusion of the first 389 amino acids of diphtheria toxin to amino acids 2-184 of mature human LIF, using a linker of 34 amino acids that includes six consecutive histidine residues. The latter span allows for single-step purification of the fusion protein by Ni2+-resin affinity chromatography. This linker provides a high degree of flexibility between the diphtheria toxin and LIF domains, thereby permitting aggregation-free refolding of the chimeric protein while bound to the affinity column. Both LIF and DT-(1-389)-LIF-

Recombinant toxins in haematologic malignancies and solid tumours

“…In the same family as CNTF is leukaemia inhibitory factor (also known as cholinergic differentiation factor), and LIF fused to truncated DT was also cytotoxic toward LIF-receptor bearing neuroblastoma cells [240]. Gastrin releasing peptide (GRP), a bombesin-like peptide, was fused to DAB 389 to target small cell lung cancer (SCLC) cells.…”