Butyric acid, a short-chain fatty acid physiologically present in human large gut, is derived from bacterial fermentation of complex carbohydrates. It has been shown to reduce the growth and motility of colon cancer cell lines and to induce cell differentiation and apoptosis. Apoptosis is considered a result of normal colonocyte terminal differentiation in vivo. The aim of this study was to characterize the cellular mechanisms regulating differentiation of colon cancer cells stimulated with sodium butyrate (NaB). The two human colon cancer cell lines Caco-2 and HT-29 were treated with NaB at physiologically relevant concentrations. Alkaline phosphatase (ALP) activity, a marker of colonocyte differentiation, was increased 48 hr after treatment with 1 mM NaB. Higher doses of NaB (5 and 10 mM) induced apoptosis of the cells and failed to stimulate the colonocyte differentiation. Therefore, we assumed that butyrate augments cell differentiation and induces apoptosis, acting via various intracellular mechanisms, and butyrate-mediated programmed cell death cannot be considered a consequence of colonocyte terminal differentiation. The effect of NaB on ALP activity was significantly attenuated in the presence of inhibitors of protein kinase C and JNK. Inhibition of MEK-ERK signal transduction pathways augmented the impact of butyrate on colonocyte differentiation. These results suggest that butyrate could influence the colonocyte differentiation via modulation of the activity of cellular protein kinases and signal transduction.

The free radical scavenging ability of an ethanolic extract of propolis (EEP) was demonstrated by electron spin resonance spectroscopy, when 2,2-diphenyl-1-picrylhydrazyl (DPPH) was treated with increasing concentrations of EEP. It was shown that the DPPH signal intensity was inversely related to the EEP concentration and to the reaction time. It is assumed that the ability of components in EEP to donate a hydrogen atom is responsible for the lowering of the DPPH-EEP signal, and reflect the anti-oxidative nature of EEP.

Infectious DNA from the tumor-inducing polyoma virus and pneumococcal-transforming DNA can be recovered from the blood of mice in biologically active form after intraperitoneal injection. Polyoma DNA appeared to undergo less inactivation than did transforming DNA. In light of these observations, the metastatic spread of cancer may possibly be favored by circulation of tumorigenic DNA in the blood stream.

Bradykinin is a mediator of inflammation, responsible for pain, vasodilation, and capillary permeability. Bradykinin receptor 1 (B1R) and bradykinin receptor 2 (B2R) are G protein-coupled receptors that mediate kinin effects. The latter is constitutive and rapidly desensitized; the former is induced by inflammatory cytokines and resistant to densensitization. The distribution of bradykinin receptors in human intestinal tissue was studied in patients with inflammatory bowel disease (IBD), namely ulcerative colitis (UC) and Crohn's disease (CD). Both B2R and B1R proteins are expressed in the epithelial cells of normal and IBD intestines. B1R protein is visualized in macrophages at the center of granulomas in CD. B2R protein is normally present in the apexes of enterocytes in the basal area and intracellularly in inflammatory tissue. In contrast, B1R protein is found in the basal area of enterocytes in normal intestine but in the apical portion of enterocytes in inflamed tissue. B1R protein is significantly increased in both active UC and CD intestines compared with controls. In patients with active UC, B1R mRNA is significantly higher than B2R mRNA. However, in inactive UC patients, the B1R and B2R mRNA did not differ significantly. Thus bradykinin receptors in IBD may reflect intestinal inflammation. Increased B1R gene and protein expression in active IBD provides a structural basis of the important role of bradykinin in chronic inflammation.

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