Effects of CSF1R and C-KIT siRNA on MKPL-1 cells. (A) siRNA-induced silencing of CSF1R was assessed by immunoblot of whole-cell lysates 72 hours after siRNA transfection. Down-regulation of CSF1R resulted in decreased phosphorylation of STAT5 and ERK. NP and CSF1R stand for siControl nontargeting siRNA pool and CSF1R SMARTpool siRNA, respectively. * indicates a nonspecific band; →, a truncated form of CSF1R. (B) Electroporation with CSF1R siRNA into MKPL-1 cells resulted in a decrease of proliferation as measured. Mean value plus SD of experiments performed in duplicate is represented. (C) Induction of apoptosis. Percentage of total population is indicated. (D) siRNA-induced silencing of C-KIT was assessed by immunoblot of whole-cell lysates 72 hours after siRNA transfection. Down-regulation of C-KIT did not affect phosphorylation of STAT5. In addition, treatment of MKPL-1 cells with C-KIT siRNA did not affect its apoptosis, as assessed by total and cleaved PARP. NP and C-KIT indicate siControl nontargeting siRNA pool and C-KIT SMARTpool siRNA, respectively. (E) Electroporation with C-KIT siRNA into MKPL-1 cells did not affect proliferation of MKPL-1 cells. Mean value plus SD of experiments performed in duplicate is represented.