Our results on eyelash morphology and growth characteristics demonstrated significant ethnic differences in Asian and Caucasian females that could provide basic information for future investigations.

We investigated the alterations of major fatty acid components in epidermis by natural aging and photoaging processes, and by acute ultraviolet (UV) irradiation in human skin. Interestingly, we found that 11,14,17-eicosatrienoic acid (ETA), which is one of the omega-3 polyunsaturated acids, was significantly increased in photoaged human epidermis in vivo and also in the acutely UV-irradiated human skin in vivo, while it was significantly decreased in intrinsically aged human epidermis. The increased ETA content in the epidermis of photoaged human skin and acute UV-irradiated human skin is associated with enhanced expression of human elongase 1 and calcium-independent phophodiesterase A2. We demonstrated that ETA inhibited matrix metalloproteinase (MMP)-1 expression after UV-irradiation, and that inhibition of ETA synthesis using EPTC and NA-TCA, which are elongase inhibitors, increased MMP-1 expression. Therefore, our results suggest that the UV increases the ETA levels, which may have a photoprotective effect in the human skin.

Selenium, an essential biological trace element, reduces the incidence of cancer. Our previous studies show that selenite inhibits tumor invasion by suppressing the expression of matrix metalloproteinases (MMP) -2 and -9. Methylseleninic acid (MSeA), an immediate precursor of methylselenol, inhibits tumor cell growth in vitro and mammary carcinogenesis in vivo. In this study, we demonstrate that MSeA suppresses pro-MMP-2 activation in a dose-dependent manner induced by 12-O-tetradecanoylphorbol-13-acetate (PMA), and further decreases the invasiveness of HT1080 tumor cells. Membrane type-1-MMP (MT1-MMP) is a crucial element in the process of pro-MMP-2 activation. Pro-MMP-2 binds MT1-MMP, using tissue inhibitor of metalloproteinase-2 (TIMP-2) as an adaptor, by forming a trimolecular complex on the cell surface. MSeA blocked MT1-MMP in a dose-dependent manner, but not TIMP-2 expression. MMP-9 and TIMP-1 levels were not affected by MSeA. Selenite induced a decrease in protein levels of both pro-MMPs -9 and -2, but not active forms of pro-MMP-2. MT1-MMP expression is regulated by NF-kappaB. Our data show that the effect of MSeA on MT1-MMP expression is mediated through suppression of NF-kappaB activity. Methylselenol generated by selenomethionine (SeMet) and methioninase (METase) inhibited pro-MMP-2 activation induced by PMA, confirming the effect of MSeA on pro-MMP-2 activity. Moreover, ROS production induced by PMA was partly decreased in the presence of MSeA. This suppression of ROS production may be related to diminished NF-kappaB activity. Thus, our results suggest that MSeA blocks tumor invasion in vitro via inhibiting pro-MMP-2 activation mediated by suppression of MT1-MMP expression, which is regulated by the NF-kappaB signal pathway.

Matrix Metalloproteinases (MMPs) are crucial enzymes for ultraviolet irradiation-induced photoaging in human skin. Ultraviolet B (UVB) stimulates dermal fibroblasts to increase MMP-1 and -3 expression and extracellular matrix (ECM) degradation in photoaging. We investigated whether phosphatase and tensin homolog (PTEN)/Akt pathway is involved in secretions of MMP-1 and -3 in human dermal fibroblasts. The increase in MMP-1 and -3 expression and secretion occurred along with the increase in PTEN and Akt phosphorylation by UVB irradiation in a dose- and time-dependent manner. However, treatment with a casein kinase 2 inhibitor, 5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole, inhibited their phosphorylations and MMP-1 and -3 secretions. Transfection of wild-type PTEN (Wt-PTEN) decreased basal and UVB-induced MMP-1 and -3 secretions, as well as activator protein-1 (AP-1) activity, while transfection of small interference RNA of PTEN (siRNA-PTEN), phosphatase-inactive PTEN (C124S-PTEN), or lipid phosphatase-inactive PTEN (G129E-PTEN) increased basal or UVB-induced MMP-1 and -3 secretions and AP-1 activity. Transfection of constitutively active Akt (Myr-Akt) also increased basal or UVB-induced MMP-1 and -3 secretions, as well as AP-1 activity. However, transfection of kinase-inactive Akt (K179M-Akt) decreased their secretions, but showed no significant change of AP-1 activity without UVB irradiation, and a significant increase of AP-1 activity with UVB irradiation. Treatment with the phosphatidylinositol 3-kinase inhibitors, LY294002 or wortmannin, downregulated basal and UVB-induced MMP-1 and -3 secretions. In conclusion, UVB irradiation increases PTEN and Akt phosphorylation in human dermal fibroblasts, and these inhibition of PTEN and activation of Akt by phosphorylation are involved in UVB-induced MMP-1 and -3 secretions partly through upregulation of AP-1 activity.