Hello ,
Actually ,three months ago I tried to knockdown cyp26B1 and CYP26A1 in HUVEC and HOSMC cells .I used Lipofectamin 2000 but I could not get any significant .Do anyone have experience with siRNA transfection.
Elmabsout.

If the cell line could be transfect by Lipofectamine 2000 and you have already used QRT-PCR or western to determine the knock down efficiency. One possible reason is the transfection efficiency is not high enough. You can try to determine the transfection efficiency by transfecting fluorescence tagged siRNA.

Thanks a lot, I used to RT-PCR to quantification mRNA ,and I have another problem with HUVEC ,the cells started die 4 hr post-tranfection ,if I transfected in Optimum.
Ela