Expression of SCF by various murine and human tumor cell lines from multiple tissue origins and establishment of SCF-silenced tumor clones. (A) SCF expression in various murine tumor cell lines (colon cancer: MCA26, MC38; breast cancer: JC, 4T1; melanoma: B16). (B) SCF expression in various human tumor cell lines (colon cancer: HCT15, SW620, DLD-1, Colo205; breast cancer: MDA-MB435). Total RNAs were prepared from the murine and human tumor cell lines and SCF mRNA expressions were analyzed by RT-PCR. (C) SCF expression in SCF-silenced MCA26 clone and in control mock-transfected clone. Multiple stable SCF knockdown and mock-transfected control MCA26 clones were established as described in “Methods.” RNAs were prepared from representative clones and SCF expressions were analyzed by RT-PCR. (D) The protein expression of SCF in mock-transfected control and SCF-silenced MCA26 clones. Cell lysates were prepared and SCF concentration was measured by ELISA.