A) SP cells and NSP cells were isolated from RENT4 cells. Verapamil treatment blocked the dye efflux and rendered the SP cells undetectable.
B) SP cells and NSP cells were incubated with MF medium for ten weeks. The growth rate was investigated. RSP cells grew faster than RNSP cells after seven weeks of culturing. Cell numbers are represented as the means ± SEM from three independent experiments. * p < 0.05 RSP cells and RNSP cells harboring mutant [12Val] versions of KRAS 4B (RSPK12V cells and RNSP-K12V cells) were established as described in Materials and Methods. Expression of [12Val] KRAS gene was confirmed by RT-PCR using the human KRAS cDNA specific primers.
