Effects on cultured human colon cancer cells of combination of transfection with cationic multilamellar liposome-entrapped plasmids containing cDNA of human interferon-β (hIFN-β) or interferon-γ (hIFN-γ) (RN-hIFN-γ or RN-hIFN-γ) and an anti-cancer drug (5-fluorouracil or cisplatin) were examined. At 16h after the addition of liposome-entrapped RN-hIFN-β or RN-hIFN-γ, the medium was exchanged for the fresh medium containing anti-cancer drug, of which effect of growth inhibition was strengthened synergistically, and the efficacy increased corresponding to the dose of the drug.
The asialoglycoprotein receptor-mediated gene transfer system is a useful method for targeted gene transfer to liver cells. This system is based on the finding that hepatocytes have a specific receptor for asialoglycoprotein. The efficiency of this system, however, is very low. To enhance the efficiency of this system, we examined the effect of a fusogenic peptide from influenza virus on asialoglycoprotein receptor-mediated gene transfer. It is known that this peptide disrupts the endosomal membrane at acidic pH, and allows DNA to escape from the endosome into the cytosol before attack by lysosomes. A recombinant plasmid DNA carrying a reporter gene was complexed with a poly-L-lysine-conjugated 23-residue peptide derived from influenza virus hemagglutinin HA2 N-terminal peptide and galactose-poly-L-lysine conjugate, and added to the culture of HepG2 cells. When the fusogenic peptide was incorporated into the DNA complex with the galactose-poly-L-lysine conjugate, the luciferase activity in the HepG2 cells was more than 500-fold higher than that of cells transfecred with the DNA complex without the peptide. An antibody against the asialoglycoprotein receptor blocked the transfer of the DNA complex, indicating that the DNA complex was specifically transferred into the HepG2 cells by asialoglycoprotein receptor-mediated endocytosis. Our results suggest that the asialoglycoprotein receptor-mediated gene delivery system using this fusogenic peptide may be useful for the development of gene therapy targeting the liver.
The effect of non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac and naproxen on xenobiotic-metabolizing enzymes was studied in male Swiss mice given the drugs in their diet. Diclofenac at levels of 25, 75, and 375ppm, and naproxen at 150, 500, and 1, 500ppm, were given for a period of 4 weeks. Control animals consumed a similar diet deprived of the test NSAIDs. Feeding of NSAIDs did not affect the activity of arylhydrocarbon hydroxylase, whereas the level of cytochrome P-450 (P-450) was significantly decreased in liver and lungs of the animals. The maximum decline in content of the enzyme was found at the largest dose of NSAIDs. On the other hand, the activity of glutathione-S-transferase (GST) was significantly increased in the two organs by both drugs. However, hepatic activity of the enzyme after induction by 375ppm diclofenac was almost 1.37 fold greater in comparison to that after induction by 1, 500ppm naproxen. In lungs, this ratio was found to be 1.76. Like GST, reduced glutathione (GSH) levels in the liver and lungs of the animals were also significantly increased. The maximum increase in GSH in lungs elicited by the two NSAIDs was similar. The results of this study indicate that diclofenac might prove to be a better chemopreventive agent against xenobiotics because of the higher induction of GST activity by it.
We examined the life span and blood biochemical data of Sprague-Dawley rats after left renal artery ligation (RAL). The survival rate of rats with a single kidney was 50% at the 66th week, 50% survival of control (sham-operated) rats was at the 92nd week. The RAL group showed an average life span of 68 weeks, as compared with 96 weeks for the control rats. When the RAL group was divided into three subgroups depending on the life span, we found that the body weight in the subgroup with the shortest life span was increased significantly for 25 weeks after the operation, whereas that in the subgroup with the longest life span increased more slowly. Moreover, even 10 weeks before death, the body weight in the subgroup with the shortest life span was found to be heavier than that in either of the other two subgroups. The blood urea nitrogen and creatinine levels already showed high values in the RAL group by the 4th week after the operation, and they were more than two-fold the values in the control rats by the 48th week. These results suggest that unilateral ligation of the renal artery causes abnormal metabolism of proteins and anemia due to malfunction of the remaining kidney and may be a factor in shortening the life span.
The therapy of insulin-dependent diabetes mellitus (IDDM) is achieved only by daily subcutaneous injections of insulin, and compounds that can replace insulin or insulin-mimetics for oral administration need to be developed. Vanadate ion, vanadyl ion and their complexes have been reported to possess insulin-mimetic activities in both in vitro and in vivo experiments. On the basis of our recent preliminary finding that a bis(picolinato)oxovanadium (VO-PA) complex has a possible hypoglycemic activity when given by oral administration to streptozotocin-induced diabetic rats (STZ-rats), we synthesized several analogs of the VO-PA complex and examined the relationship between their structures and insulin-mimetic activity. Bis(methylpicolinato)oxovanadium (VO-MPA) complex, which has a relatively high partition coefficient among the prepared complexes, was found to be effective to inhibit in vitro release of free fatty acid from isolated rat adipocytes, similar to VO-PA. VO-MPA complex was thus given to STZ-rats by intraperitoneal injection or oral administration, and was found to normalize the serum glucose levels without the body weight loss. Especially, on oral administration of the complex, the normal serum glucose level was maintained for 80 days after the cessation of the complex administration. The long-acting character of the complex was suggested by the fact that vanadium is incorporated in bone as well as in kidney or other organs. Based on these observations, VO-MPA was proposed to be an useful agent not only to treat IDDM in experimental animals but to analyze the mechanism for the insulin mimetic activity of vanadium compounds.
The effects of fructooligosaccharides added to guar gum on plasma lipids and cecal short-chain fatty acids (SCFAs) in mice were studied. Male Crj:CD-1 (ICR) mice were fed an MF diet for 34 weeks, and then the MF diet was replaced with a semisynthetic diet supplemented with 5% guar gum or 5% guar gum plus 3% fructooligosaccharides. The mice fed the guar gum or guar gum-fructooligosaccharide diet for 3 weeks. There was no significant difference in cecal bacterial counts or cecal content between the two diet groups. There was, however, a significant difference in their plasma triglyceride concentrations. The plasma triglyceride concentration was significantly lower in the mice fed the guar gum diet than in those fed the guar gum-fructooligosaccharide diet. However, no significant difference in plasma total cholesterol concentration was noted between the two diet groups. The butyric acid concentration in the guar gum group was significantly higher than that in the guar gum-fructooligosaccharide group. No significant difference in propionic acid or acetic acid concentration was noted between the groups. The difference in the plasma triglyceride concentration between the guar gum and guar gum plus fructooligosaccharide groups might be related to a difference in floral metabolism, floral composition, or both.