Effect on liver tumor growth in rats of allopurinol and 5-fluorouracil in combination with hepatic artery ligation

Tumour S-phase activity, nucleotide profile and RNA levels after hepatic artery occlusion and reperfusion in an experimental model of secondary liver carcinoma

Rats with carcinoma of the colon implanted into the liver were subjected to hepatic arterial occlusion for 30-120 min. Regrowth of the tumour after reperfusion was evaluated by immunohistological determination of S-phase activity after injection of bromodeoxyuridine. Levels of RNA and nucleotides, and energy charge, were also examined. DNA synthesis was observed in the entire tumour except in necrotic areas of controls and after 30-min ischaemia with 2-h reflow. Almost all tumoral DNA synthesis was abolished by 2 h of ischaemia, except in a few cells in the tumour periphery, which after reperfusion for 22 and 40 h grew into a band-like concentric layer. Levels of energy charge, adenosine, uridine and guanosine 5'-triphosphates, and RNA were unchanged in liver tissue after hepatic arterial occlusion but decreased in the tumour. In conclusion 30 min of ischaemia did not damage the tumour cells substantially. Ischaemia for 2 h seemed able to kill the tumour cells except those in the periphery in areas nourished by the portal vein where tumour regrowth was seen. The liver tissue was not damaged.

Organ distribution and antitumor activity of free and liposomal doxorubicin injected into the hepatic artery

The plasma levels, organ distribution, and in vivo antitumor activity of free and liposomal doxorubicin injected into the hepatic artery of rats bearing W256 liver tumors were studied. The administration of liposomal doxorubicin resulted in liver-tumor and liver-parenchyma doxorubicin areas under the curve (AUCs) that were 4.7- and 3.8-fold, respectively, those obtained after the administration of free doxorubicin. Spleen and plasma AUCs were also increased by 2.8 and 2.5 times, respectively, following administration of the liposomal form. In contrast, liposomal doxorubicin did not affect heart AUCs; peak doxorubicin levels in heart tissue were three times lower in animals treated with liposomal doxorubicin. Following treatment with the liposomal form, the cumulative urinary excretion of doxorubicin at 8 h was 38 times lower. In good correlation with these findings, liposomal doxorubicin (2.35 mg/kg on day 7) was more effective than free doxorubicin against liver W256 tumors as measured by tumor-growth inhibition at 5 days after treatment (16% for liposomal doxorubicin versus -53.7% for free doxorubicin, P < 0.05) and increased life span (ILS; 108% for liposomal doxorubicin versus 27% for free doxorubicin, P < 0.05). These results demonstrate that as compared with free doxorubicin, the administration of liposomal doxorubicin into the hepatic artery results in higher drug levels in the liver tumor and enhanced antitumor activity while maintaining the cardioprotective effect of the liposome carrier as suggested by the decreased peak drug levels measured in the heart tissue.

Incorporation of 5-fluorouracil into rat liver tumor and normal tissues and the liver nucleotide profile after administration by the hepatic artery during portal venous branch ligation

A therapeutic dose of labelled 5-fluorouracil (5-FU) was infused via the hepatic artery during 30 min with or without ligation of the left portal venous branch in Wistar rats with a secondary liver cancer in the left lateral lobe. After another 60 min, the incorporation of 5-FU into the acid soluble fraction (ASF), ribonucleic acid (RNA) and deoxyribonucleic acid (DNA), was determined in tumor, ligated and unligated liver lobes, small intestine, kidney, and bone marrow. The liver nucleotide profile was examined with isotachophoresis. Portal venous branch ligation (PVBL) caused the following changes, compared with the unligated control group: in the tumor, the incorporation of 5-FU into RNA and DNA decreased and the ratio RNA/acid-soluble fraction labelling decreased. The incorporation increased in intestinal and bone marrow RNA. It was unchanged in liver and kidney. The ratio of tumor to peripheral normal-tissue (small intestine, bone marrow, and kidney) labelling of RNA and DNA decreased. Liver nucleotides (F)UTP, (F)UDP-glucuronic acid, (F)UDP-N-acetylhexosamine, and NAD were lower in the ligated than in the unligated liver lobe. ATP and energy charge did not decrease significantly. In conclusion, PVBL in conjunction with hepatic arterial administration of 5-FU increased systemic drug exposure and possibly decreased hepatic tumor anabolism. It has not been examined how this interferes with the therapeutic effect.