ANTITUMOR-ACTIVITY OF SYNTHETIC OLIGONUCLEOTIDES WITH SEQUENCES FROM CDNA-ENCODING PROTEINS OF MYCOBACTERIUM-BOVIS BCG

Thirteen kinds of 45-mer or 30-mer synthetic oligonucleotides with seq uences randomly selected from the cDNA encoding three kinds of protein of Mycobacterium bovis BCG were tested for their antitumor activity i n a murine tumor system. Six out of the 13 single-stranded oligonucleo tides which contained one or more hexameric palindromic sequences show ed strong antitumor activity while the others without palindromic stru cture did not. Namely, repeated intralesional injections of 100-mu-g o f the 6 oligonucleotides caused regression of the established tumor bu t the other 7 were ineffective. When tumor cells were mixed with 100-m u-g of an effective oligonucleotide and injected into mice, tumor grow th was markedly suppressed. These results suggested that palindromic s tructure is essential for the antitumor activity of the synthetic olig onucleotides.