Expression and Purification of Human Stem Cell Factor and Its Effect on the Growth of A549 Cells

Stem cell factor (SCF) is a type of hematopoietic cytokine that functions in early hematopoietic stem cells. SCF, together with its cognate receptor c-kit, plays crucial roles in cell survival, proliferation, and differentiation. A dysregulated SCF/c-kit system is reportedly, associated strongly with various kinds of cancer in humans. However, the function and mechanism of SCF in non-small cell lung cancer (NSCLC) remains to be elucidated to date. In this context, the present study attempted to purify two different sizes of human SCF proteins and then investigate the effect of these exogenous SCFs in A549 cells. First, the homo sapiens Kit ligand (KITG) transcript variants a and b were amplified, and recombinant pET-30a vectors were constructed. Soluble His-SCF and His-SCF-2 were then expressed and purified using 0.1 mM isopropyl-β-D-1-tiogalactopiranoside (IPTG) at 25 °C and 0.3 mM IPTG at 25 °C, respectively. MTT assay was conducted next, which revealed that the purified proteins significantly promoted A549 cell activity and increased the phosphorylation of P65. Further, NF-κB pathway blockade was achieved through treatment with BAY11-7082, and it was observed to decrease the A549 cell activity promoted by the purified proteins. These findings provided insights into the biological role of SCF in the development of NSCLC.