Efficacy of p120 antisense-mediated therapy for pancreatic cancer.

p120 antisense oligodeoxynucleotides were used to determine whether they inhibited cell growth of MIA PaCa-2, a highly tumorigenic human pancreatic carcinoma cell line. Growth inhibition assays were determined in vitro by the ability of these oligomers to inhibit DNA synthesis and cell growth. For in vivo studies, nude mice were injected with cells and palpable tumors were found in 16 of 20 animals by day 14. Sixteen animals (8 in each group) were then treated daily (25 mg/kg intraperitoneally) for up to 40 days with nonsense control oligomers or p120 antisense oligomers. p120 Antisense oligomers inhibited the in vitro proliferation of MIA PaCa-2 cells in a dose-dependent manner, and optimal growth inhibition of greater than 90% was achieved at an antisense oligomer concentration of 100 micromol/L. The tumor volume was calculated for antisense- and nonsense-treated animals. Fifteen days after the beginning of treatment, control animals had a significantly greater (P=0.0035) tumor volume (425=244 mm3 above baseline) as compared to p120 antisense-treated animals (166+/-116 mm3). Seven of the eight control animals formed tumors that had a volume greater than 1200 mm3 45 days after treatment was begun, whereas only three of eight p120 antisense-treated animals had tumors that were this large. Two of the latter three animals had relatively large, palpable tumors (>150 mm3) prior to treatment. Twenty days after treatment was stopped (day 60), all animals had tumors larger than 1200 mm3. p120 Antisense oligomers were effective for inhibiting in vitro growth of the pancreatic cancer cell line MIA PaCa-2. In preliminary studies, p120 antisense oligomers appeared to inhibit the rate of growth in nude mice; however, no cures were achieved. The most effective response was seen in animals with initial low tumor burden.