Anti-inflammatory effect of caffeic acid methyl ester and its mode of action through the inhibition of prostaglandin E2, nitric oxide and tumor necrosis factor-alpha production

The anti-inflammatory effects of caffeic acid (CA), caffeic acid methyl ester (CM) and di-O-acetylcaffeic acid (DAC) were investigated in rats using the carrageenin-induced edema model and the antinociceptive effects of these compounds were also assessed in mice by means of the acetic acid-induced abdominal constriction test and hot plate test. CM (10mg/kg, p.o.) showed the most potent anti-inflammatory and antinociceptive effects in these animal models. To investigate the mechanism of the anti-inflammatory action, we examined the effects of these compounds on the lipopolysaccharide (LPS)-induced NO and PGE2 responses in the murine macrophage cell line, RAW 264.7. Our data indicate that CM is the most potent inhibitor of NO and PGE2 production and it also significantly decreased tumor necrosis factor-alpha (TNF-alpha) release. Consistent with these observations, the protein and mRNA expression levels of iNOS and COX-2 were found to be inhibited by CM in a dose-dependent manner. Furthermore, CM inhibited the nuclear factor-kappaB (NF-kappaB) activation induced by LPS, which was associated with the prevention of the degradation of the inhibitor kappaB, and subsequently with decreased p65 protein levels in the nucleus. Taken together, our data indicate that the anti-inflammatory properties of CM might result from the inhibition of iNOS, COX-2 and TNF-alpha expression through the down-regulation of NF-kappaB binding activity.     

U-shaped Dose Response in Vasomotor Tone: A Mixed Result of Heterogenic Response of Multiple Cells to Xenobiotics

U-shaped response has been frequently encountered in variousbiological areas including epidemiology, toxicology, and oncology.Despite its frequent observation, the theory of U-shaped responsehas been crippled by the lack of a robust mechanism underlyingand incomplete in vitro and in vivo correlation. In the presentstudy, a novel mechanism is provided for a U-shaped response,based on the findings of agonist-induced vasomotor tone changeaffected by menadione (MEN) (synthetic vitamin K₃), a reactiveoxygen species generator, and arsenic, an environmental pollutant,which showed typical U-shaped responses in both in vitro aorticcontractile response and in vivo blood pressure. U-shaped responsesby MEN and arsenic were a combined result from heterogenic susceptibilitiesand responses of multiple target cells composing blood vessels,that is, endothelium and smooth muscle. Notably, endothelium,a regulator of vasomotor tone, was primarily affected by low-dosestimuli, whereas smooth muscle, an effector of vascular contraction,was affected later by high-dose. The dysfunction of smooth musclewas produced by high-dose MEN-induced hydrogen peroxide, resultingin the attenuation of vascular contractile reactivity, whereaslow-dose MEN-induced superoxide led to the quenching of vasodilatorynitric oxide in endothelial cells, resulting in the enhancementof vasoconstriction. This mechanistic theory, the differencein susceptibilities and responses to a common stimulus betweenregulator and effector components of a system, could give anew insight into the explanation of various U-shaped responsesand provide a new evidence for the need of the risk assessmentof toxicants with a wider dose range.     

Berberine inhibits growth of the breast cancer cell lines MCF-7 and MDA-MB-231

The effects of berberine on the behavior of breast tumors have not yet been established. To determine whether this compound is useful in the treatment of breast cancer, we analyzed the impact of berberine on the human breast cancer cell lines MCF-7 and MDA-MB-231 cells. Berberine was added to proliferating MCF-7 and MDA-MB-231 cells in culture. Following treatment, changes in cell growth characteristics such as proliferation, cell cycle duration, and the degree of apoptosis were assayed. Following berberine treatment, a time-dependent reduction in proliferation was observed in both cell lines at differing concentrations: 20 microM for MCF-7 and 10 microM for MDA-MB-231 cells. Annexin V staining showed an increase in apoptosis in both cell lines of 31 % in MCF-7 and 12 % in MDA-MB-231 cells compared to their respective controls. In addition, 12 % of the MCF-7 cells were arrested at G0/G1, compared to 62 % of control cells. These results demonstrate that treatment with berberine inhibits growth in both MDA-MB-231 and MCF-7 cells. In addition, they show that this partly occurs through the induction of apoptosis in MDA-MB-231 cells, and through both cell cycle arrest and induction of apoptosis in MCF-7 cells. Thus, berberine may be a novel therapeutic drug for breast cancer.     

Loss of Rab25 promotes the development of skin squamous cell carcinoma through the dysregulation of integrin trafficking

Rab25 can function as both a tumor suppressor and a tumor promoter across different tissues. This study sought to clarify the role of Rab25 as a tumor suppressor in skin squamous cell carcinoma (SCC). Rab25 loss was closely associated with neoplastic transition in both humans and mice. Rab25 loss was well correlated with increased cell proliferation and poor differentiation in human SCC. While Rab25 knockout (KO) in mice did not induce spontaneous tumor formation, it did significantly accelerate tumor generation and promote malignant transformation in a mouse two-stage skin carcinogenesis model. Xenografting of a Rab25-deficient human keratinocyte cell line, HaCaT, also elicited neoplastic transformation. Notably, Rab25 deficiency led to dysregulation of integrins β1, β4, and α6, which matched well with increased epidermal proliferation and impaired desmosome–tight junction formation. Rab25 deficiency induced impairment of integrin recycling, leading to the improper expression of integrins. In line with this, significant attenuation of integrin β1, β4, and α6 expression was identified in human SCCs where Rab25 was deficient. Collectively, these results suggest that loss of Rab25 promotes the development and neoplastic transition of SCC through dysregulation of integrin trafficking. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.