Patent ID: 8273722

Claim:
A method for producing a protein-containing product from CHO cells, the method comprising: culturing recombinant host CHO cells containing nucleic acid encoding at least a portion of the protein-containing product; contacting the recombinant host CHO cell with a synthetic, chemically modified siRNA having a delivery facilitating conjugate linked to a polynucleotide of the siRNA, said contacting being under conditions in which the synthetic siRNA passively transfects the recombinant host CHO cell in an amount sufficient to inhibit expression of a first protein, wherein the synthetic, chemically modified siRNA includes: a sense strand having: 2′-O-methyl modifications on the ultimate and penultimate nucleotides; 2′-O-methyl modifications on each pyrimidine nucleotide; and a cholesterol or cholesterol derivative conjugate coupled to the 3′ end of the sense strand through a linker having a 3-member to 8-member carbon chain; and an antisense strand having: 2′-fluorine modifications on each pyrimidine nucleotide a 5′ terminal phosphate; a U-U 3′ overhang that includes phosphorothioate internucleotide linkages; and one of an A-A mismatch, a U-U mismatch, a C-C mismatch, or a G-G mismatch between nucleotide 6 from the 5′ end of the sense strand and the opposite nucleotide on the antisense strand, wherein expression of the first protein decreases the production efficiency of the protein-containing product; incubating the recombinant host CHO cells with the synthetic siRNA under conditions that inhibit expression of the first protein; incubating the recombinant host CHO cells under conditions that express the protein-containing product; and recovering the protein-containing product.