Method for producing recombinant oncolytic adenovirus with modified E1a cancer-specific promoter

A method for producing a recombinant oncolytic adenovirus comprising:

• (a) infecting an A549 host cell with the recombinant oncolytic adenovirus to produce an infected A549 host cell or introducing a nucleic acid comprising a nucleotide sequence encoding the recombinant oncolytic adenovirus into an A549 host cell;
• and
• (b) suspension culturing the A549 host cell in a serum-free medium, under conditions to permit production of the recombinant oncolytic adenovirus,
• wherein the recombinant oncolytic adenovirus comprises an E1a gene comprising an E1a protein coding region operably linked to a modified regulatory sequence comprising (i) deletion of a functional Pea3 binding site, (ii) deletion of a functional E2F binding site, (iii) deletion of a functional TATA box, (iv) deletion of a functional CAAT box, (v) deletion of the nucleotides corresponding to the nucleotides from 195-244 of the Ad5 genome (SEQ ID NO:
• 1), or (vi) has two, three, or four of (i), (ii), (iii), and (iv).