A) Cells were isolated from RSP-K12V-tumors and RNSP-K12V-tumors and cultured on collagen-plates with DMEM containing 10% FBS. The primary cultured RSP-K12V-tumor cells exhibited long-term proliferating capacity in vitro. In contrast, the primary cultured RNSP-K12V-tumor cells failed to grow and died within two weeks.
B) A senescence associated β-gal (SA-β-gal) staining was performed. SA-β-gal activity was detected in RNSP-K12V tumor cells, but not in RSP-K12Vtumor
cells.
C) RSP-K12V-tumor cells and RNSP-K12V-tumor cells were transplanted into the subcutaneous tissue of nude mice. RSP-K12V-tumor cells produced tumors. In contrast, RNSP-K12V-tumor cells did not form tumors.
D) Expression of K-ras in each type of primary cultured cells was confirmed by RT-PCR.
