F-curve of the second derivative, which Heat shock proteins represents the point of maximum curvature of the growth curve. CT and depending on the design cycle were used to interpret the results. Results and discussion Generation of NSCLC cells resistant model irreversibly towards an irreversible EGFRInhibitor To the development of resistance to EGFR kinase inhibitor in the treatment of NSCLC, we have the PC 9 NCSLC derived cell line. These cells contain a verst Rktes EGFR allele with a deletion in the kinase-Dom Ne, and they exhibit a pronounced Gte sensitivity to EGFR inhibitors. Clones resistant to PC 9 to mutation to create mechanisms, we evaluated cells exposed to PC 9 mutagen ethyl methane sulfonate, and then they grow permanently HKI 272, an irreversible inhibitor of EGFR kinase Dual / HER2 that is at present the clinical activity for t. The cells were in 0.2 amol / l HKI 272, the ann the concentration of pharmacological Kept hert. Although the vast majority of PC-9 cells were quickly get this treatment Tet, about 1 in 2,000 cells into colonies led to f4 to 6 weeks in the presence of drugs. Several individual colonies were expanded and they were all found to have an average increase compared to the resistance of HKI-272 F10 show times on parental PC 9 cells, as indicated by their IC 50 in a test for the survival of the cell measured. If, in the absence of drug for up to 6 weeks bred, kept all their clones HKI 272 Ph MPC-3100 958025-66-6 Phenotype, suggesting a stable mechanism of resistance. Although all resistant clones show hnlichen degrees of HKI 272 of resistance, other biochemical analyzes revealed two distinct classes of clones: those where the phosphorylated EGFR is effectively suppressed by drugs, and those that retain phosphorylated EGFR in the presence of drugs. For simplicity, we refer to clones with drug suppressed EGFR phosphorylation in the Class A and nonsuppressible phosphorylated EGFR with the class as a particular example is the suppression of phosphorylated EGFR by Class A drugs in clones no permanent Ph Genotype EGFR is activated when cells grown in the absence of the drug.
The absence of EGFR activity t in class A clones suggests that these cells can survive an alternative way addictive. It was reported that the MET gene amplification or activation of the IGF IR path m Possible mechanisms of acquired resistance to gefitinib in vitro. Therefore tested whether each of these pathways in Class A of the resistant clones were selected, but found that neither MET or IGF IR protein levels increased Hte phosphorylation in the 272 HKI-resistant clones from parental cells showed CP 9. We then found that all 272 HKI-resistant clones cross-resistant to both gefitinib and erlotinib, were suggesting that the acquired resistance is not specifically reflect a unique mechanism for irreversible inhibitors. In addition, the clones were sumatriptan significantly widerstandsf Higer to gefitinib and erlotinib than they were HKI 272nd Thus, these clones on average 10 times more resistance to HKI 272, but 100 times more resistance to gefitinib and erlotinib. In particular, parents PC 9 cells were somewhat more sensitive to gefitinib and erlotinib than they were HKI 272nd Ac.