Growth-inhibitory effects of combination chemotherapy for human pancreatic cancer cell lines

Sensitivities to anti-tumor drugs, mitomycin C (MMC), aclarubicin hydrochloride (ACR), doxorubicin hydrochloride (ADR), cisplatin, and 5-fluorouracil (5FU), were examined using PK-1, -8, -9, -12, -14, and -16 cell lines derived from human pancreatic cancer. These cell lines showed different sensitivities to each of the above anti-tumor drugs. The concentrations required for 50% growth-inhibition (IC50) after 2 hours of exposure were 0.096 to 0.35 micrograms/ml for MMC, 0.0074 to 0.0076 micrograms/ml for ACR, 0.033 to 0.23 micrograms/ml for ADR, 0.35 to 1.9 micrograms/ml for cisplatin, and 21 to 42 micrograms/ml for 5FU, IC50 of each anti-tumor drug decreased significantly after 48 hours of exposure. The combination of any two out of MMC, ACR, and 5FU showed synergistic inhibition of the growth of PK-1 and PK-8 cell lines. These results show that MMC, ACR, ADR, cisplatin, and 5FU have sufficient anti-tumor effect against six human pancreatic cancer cell lines even at clinically achievable concentrations and exposure times, and chemotherapy for pancreatic cancers requires naturally effective drug delivery into cancer tissues.