[Inhibition of cell proliferation and C-myc cancer protein expression in human colon adenocarcinoma cell line HT29 with VIP-131I-ASON].

A 15-mer phosphorothioate antisense oligonucleotide (ASON) complementary to the translation start region of the C-myc oncogene mRNA was labeled with 131I or 125I and the labelled compound was linked to the vasoactive intestinal peptide (VIP) to be bound covalently to a polylysine chain so as to deliver oligonucleotide into tumor cells. The effect of the VIP as carrier on cell uptake of ASON in tissue culture was evaluated in a human colon adenocarcinoma HT29 cell line. The efficacy of VIP-131-ASON on cell growth was evaluated using the MTT assay. Expression of c-myc-encoded protein was measured by flow cytometry. Sense and nosense control Oligonucleotides with VIP carrier were used as control. The results showed that VIP competed effectively with VIP-125I-ASON to bind the HT29 cells. Cell uptake was increased 3-4 fold using the VIP carrier compared to the same dosage of naked DNA. HT29 cells treated with VIP-131I-ASON complexes exhibited 4-fold lower proliferation than those treated with 13I-ASON and 6-fold lower proliferation than those treated with radioiodinated Sense and nosense DNA. Cancer protein expression of HT29 cells treated with VIP-131I-ASON was decreased 2-fold compare with that in 131I-ASON treated cell. The use of a VIP carrier greatly increased 131I-ASON cellular uptake and inhibition of cell proliferation and C-myc cancer protein expressing in HT29 cell by radioiodinated antisense Oligonucleotides.