Figure 4

Effects on MTX sensitivity of treatment with siRNAs against DKK1, UGT1A s or EEF1A1. (a-f) Treatment with siDKK1 was performed in HT29 cells (a, d), siUGT1A was transfected in MDA-MB-468 cells (b, e) and the effects of siEEF1A1 were determined in MIA PaCa-2 cells (c, f). Treatments were performed as described in Methods, and MTX was added after 48 h. Cell viability was determined 3 days after MTX treatment (d-f). (d-f) A siRNA against dhfr was transfected in each of the three cell lines, and its effects on cell viability are presented. For determination of mRNA levels, real-time RT-PCR was performed with 500 ng of total RNA extracted 48 h after siRNA transfection (a-c). All results are expressed as percentages relative to the non-related negative control siRNA (NR-siRNA). Values are the mean of three independent experiments ± SE. *P < 0.05, **P < 0.01 and ***P < 0.001.