Figure 6.

IFNγ suppresses colony formation and proliferation of primary 4102 tumor cells but not of the late stage variant. (A) Analysis of the effects of IFNγ on colony formation and proliferation of various 4102 lineage cells in vitro. (B) Analysis of the phosphorylation of STAT1 of various 4102 lineage cells. Cells were treated by IFNγ and lysed after 0, 45 and 75 min of treatment. Proteins were separated in two parallel gels and transferred onto PVDF membranes for detection of phosphorylated STAT1 (pSTAT1) and total STAT1 (STAT1). Actin was used as internal loading control. Data show that administration of IFNγ leads to Tyr701 phosphorylation of STAT1 in both PRIM2 and LatePRO, indicating intact IFNγR/Jak1 signaling system in both primary and late progressor tumors.