Our previous studies revealed that REIC/Dkk-3 was expressed various tissues, including skin keratinocytes. The aim of the present study was to identify the factors that regulate the expression of the dickkopf Wnt signaling pathway inhibitor 3 (REIC/Dkk‑3) tumor suppressor gene in normal human skin keratinocytes (NHKs). Several growth factors and cytokines that have previously been reported to be involved in the growth and differentiation of keratinocytes were screened as potential regulators. Western blot analysis was performed using protein from NHKs cultured with/without various factors including the epidermal growth factor, tumor necrosis factor‑α, transforming growth factor‑β, interleukin (IL)‑1F9, IL‑6, IL‑8 and Ca2+. The results indicated that only TNF‑α downregulated REIC/Dkk‑3 expression in NHKs. Subsequently, TNF‑α was confirmed to reduce the expression levels of REIC/Dkk‑3 in mouse skin tissue and hair culture models. TNF‑α‑mediated downregulation of REIC/Dkk‑3 expression in NHKs was abrogated by the addition of a TNF‑α‑specific antibody. In conclusion, the results indicate that TNF‑α downregulates REIC/Dkk‑3 expression in normal skin keratinocytes.
Reduced expression in immortalized cells (REIC)/Dickkopf-3 (Dkk-3) overexpression, induced using an adenovirus (Ad)-REIC, has been revealed to have a dramatic therapeutic effect on multiple types of cancer. To achieve an improved therapeutic effect from Ad-REIC on cancer, our group previously developed an enhanced gene expression system, the C-TSC cassette [cytomegalovirus (CMV)-RU5' located upstream (C); another promoter unit composed of triple tandem promoters, human telomerase reverse transcriptase (hTERT), simian virus 40 and CMV, located downstream of the cDNA (TSC); plus a polyadenylation (polyA) signal]. When applied to the conventional Ad-REIC, this novel system induced the development of an enhanced product, Ad-C-TSC-REIC, which exhibited a noticeable anticancer effect. However, there were difficulties in terms of Ad-C-TSC-REIC productivity in HEK293 cells, which are a widely used donor cell line for viral production. Productivity of Ad-C-TSC-REIC was significantly reduced compared with the conventional Ad-REIC, as the Ad-C-TSC-REIC had a significantly higher ability to induce apoptotic cell death of not only various types of cancer cell, but also HEK293 cells. The present study aimed to overcome this problem by modifying the C-TSC structure, resulting in an improved candidate: A C-T cassette (C: CMV-RU5' located upstream; T: another promoter unit composed of a single hTERT promoter, located downstream of the cDNA plus a polyA signal), which demonstrated gene expression comparable to that of the C-TSC system. The improved adenovirus REIC/Dkk-3 product with the C-T cassette, named Ad-C-T-REIC, exhibited a higher expression level of REIC/Dkk3, similar to that of Ad-C-TSC-REIC. Notably, the vector mitigated the cell death of donor HEK293 cells, resulting in a higher rate of production of its adenovirus. These results indicated that Ad-C-T-REIC has the potential to be a useful tool for application in cancer gene therapy.
Aldosterone (ALD) has been shown to stimulate cardiac collagen synthesis and fibroblast proliferation via activation of local mineralocorticoid receptors. In patients with acute myocardial infarction, we demonstrated that ALD was extracted through the infarct heart and extracting ALD-stimulated post-infarct left ventricular (LV) remodeling.To evaluate the effect of mineralocorticoid receptor antagonist (MRA) spironolactone on post-infarct LV remodeling, 134 patients with first anterior acute myocardial infarction were randomly divided into the MRA (n=65) or non-MRA (n=69) groups after revascularization. All patients were administered angiotensin-converting enzyme (ACE) inhibitor and study drug just after revascularization. Left ventriculography with contrast medium was performed at the acute stage and after 1 month to evaluate LV remodeling. ALD was measured at aortic root and coronary sinus. There was no difference in the baseline characteristics including infarct size and LV performance between the two groups. However, LV ejection fraction was significantly improved in the MRA group compared with that in the non-MRA group (46.0+/-0.6% to 53.2+/-0.8% versus 46.5+/-0.8% to 51.0+/-0.8%, Pinteraction=0.012). LV end-diastolic volume index was significantly suppressed in the MRA group compared with that in non-MRA group (86.5+/-1.0 to 90.6+/-2.4 versus 87.5+/-1.3 to 106.8+/-3.5 mL/m2, Pinteraction=0.002). Transcardiac extraction of ALD through the heart was significantly suppressed in the MRA group (Pinteraction=0.001), and plasma procollagen type III aminoterminal peptide level, a biochemical marker of fibrosis, was significant lower in the MRA group compared with the non-MRA group (Pinteraction=0.002).These findings indicate that MRA combined with ACE inhibitor can prevent post-infarct LV remodeling better than ACE inhibitor alone in association with the suppression of a marker of collagen synthesis.
The hair reconstitution assay is a useful system for studying cell–cell and epithelial–mesenchymal interaction. The current method consists of transplantation of both epidermal and dermal cells, using a silicone chamber placed on an athymic nude mouse. However, because of leakage and tilting of the grafted cells, the rate and area of hair growth vary depending on the chamber. We modified this method by using a collagen sponge as a scaffold and compared two types of collagen sponges, each having different tensile strengths. A conventional collagen sponge disturbed normal hair follicle formation; in contrast, a collagen sponge containing polyglycolic acid (PGA) fiber supported proper restructuring of skin and hair follicles. These data suggested the usefulness of PGA fiber-containing collagen sponges for hair reconstitution in research and clinical applications.
