To determine the silencing efficiency of CD44 siRNA at the protein level, MDA-MB-231 cells were transfected with 60 nM CD44 siRNA at 1:6:0 and 1:6:1 siRNA:PEI-LA:HA w/w/w ratios. After 72 hrs, cells were washed with HBSS and incubated with PE-labeled anti-human control IgG and antihuman CD44 antibodies for 1 hr at room temperature. Cells were trypsinized and fixed with 3.7% formaldehyde. The surface binding of control IgG and CD44 antibodies were then quantified using BD Accuri™ C6 Plus Flow Cytometer (BD Biosciences).
The silencing efficiency of CD44 specific siRNA at the transcript level was determined by the Reverse Transcription -quantitative PCR (RT-qPCR). MDA-MB-231 cells were transfected with 60 nM CD44 siRNA at 1:6:0 and 1:6:1 siRNA:PEI-LA:HA w/w/w ratios. After 48 hrs, RT-qPCR was performed as described in RT-qPCR section below (Section 2.11).