Cervical cancer is a female-specific disease with a high incidence and mortality. MicroRNAs (miRNAs) are implicated in posttranscriptional regulation of gene expression and in the pathogenic mechanisms of cancer, suggesting their importance in diagnosis and treatment. miRNAs may have roles in the pathogenesis of cervical cancer based on the increases or decreases in several specific miRNAs found in patients with this disease. The miRNAs implicated in cervical cancer are miR-21, miR-126, and miR-143, and clinical application of these miRNAs for diagnosis and treatment is under investigation. Methods for diagnosis of cervical cancer include analysis of changes in the levels of specific miRNAs in serum and determination of aberrant hypermethylation of miRNAs. Supplementation of miR-143 or inhibition of miR-21 activity in vivo may be therapeutic strategy for cervical cancer. Previous approaches to development of siRNA as a drug have provided information for establishment of therapy based on these approaches, and an anti-miR-21 inhibitor has been developed. miRNAs also have effects on drug resistance and may be useful in combination therapy with other drugs.
The antimicrobial peptides magainin 2 and PGLa, isolated from the skin of the African clawed frog Xenopus laevis, show marked synergism [Westerhoff, H. V., Zasloff, M., Rosner, J. L., Hendler, R. W., de Waal, A., Vaz Gomes, A., Jongsma, A. P. M., Riethorst, A., and Juretic, D. (1995) Eur. J. Biochem. 228, 257-264]. We suggested previously that these peptides form a potent heterodimer composed of either parallel or antiparallel helices in membranes [Matsuzaki, K., Mitani, Y., Akada, K., Murase, O., Yoneyama, S., Zasloff, M., and Miyajima, K. (1998) Biochemistry 37, 15144-15153]. To detect the putative heterodimer by chemical cross-linking, analogues of magainin 2 and PGLa with a Cys residue at either terminus were synthesized. These cross-linking experiments suggested that both peptides form a parallel heterodimer in membranes composed of phosphatidylglycerol/phosphatidylcholine but not in either buffer or a helix-promoting 2,2,2-trifluoroethanol/buffer mixture. The isolated parallel heterodimers exhibited an order of magnitude higher membrane permeabilization activity compared with the monomeric species, indicating that the observed synergism is due to heterodimer formation.
To investigate in vivo interactions between antioxidant vitamins C and E, sparing effects of vitamin C on vitamin E as well as those of vitamin E on vitamin C were evaluated using inherently scorbutic [Osteogenic Disorder Shionogi (ODS)] rats. Rats were divided into four groups (control, vitamin E-deficient, vitamin C-deficient and simultaneously vitamins C and E-deficient). The levels of vitamins C and E in tissues were determined at 0, 14 and 21 d of deficiency. On d 14, the vitamin E concentration in plasma, liver, brain and lung of the vitamin C-deficient group was significantly lower than that of the control, in agreement with the literature concerning the sparing of vitamin E by ascorbate. The vitamin E concentration of the vitamin C-deficient group also was significantly lower in plasma, heart, liver, lung and kidney than that of the control group on d 21. On the basis of two-way ANOVA, significant interactions between vitamins C and E were observed on d 21 for vitamin E concentration in these tissues. The ascorbate level in plasma, heart, liver, muscle and kidney of the vitamin E-deficient group was significantly lower than that of the corresponding control group on d 21. Significant interactions between vitamins C and E were observed on d 21 for vitamin C concentration in these tissues. These results suggest a sparing effect of vitamin E on vitamin C, an effect that was observed for the first time in this study. These results suggest that the interaction between vitamins C and E exists in vivo and that the extent of the interaction depends on the tissue. Thiobarbituric acid reactive substances (TBARS) in plasma and liver of the vitamin C-deficient rats were significantly higher than those of the control and the vitamin E-deficient groups on d 21, suggesting that the deficiency of vitamin C caused a larger increase in oxidative stress than the deficiency of vitamin E. TBARS of the liver in rats deficient in both vitamins C and E were significantly higher than those in all other groups, suggesting an additive effect of the deficiencies of vitamins C and E on hepatic TBARS. These data suggest that in vivo, vitamins E and C interact, and each can exert sparing effects in the absence of the other.
After 12 h of thioacetamide (500 mg/kg body weight) administration to rats, the activity of caspase-3-like protease in the liver increased significantly compared to that in the control group. In plasma, the activity of caspase-3 was barely detectable in the control rat, but had increased significantly after 24 h of drug administration along with a dramatic increase in GOT. These results indicate that thioacetamide causes apoptosis in the liver by activating caspase-3, which is released to plasma by successive necrosis. At 24 h, the concentration of liver lipid hydroperoxides, a mediator of radical reaction, was 2.2 times as high as that of control rats. After 12 and 24 h of thioacetamide administration, the liver concentrations of vitamins C and E decreased significantly. The decrease of antioxidants and formation of lipid hydroperoxides 24 h after thioacetamide administration support the view that extensive radical reactions occur in the liver during the necrotic process.
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