involucrin and calcipotriene

The active vitamin D3 regulates proliferation and differentiation of epidermal keratinocytes. Recently topical vitamin D3, tacalcitol, calcipotriol, and maxacalcitol are widely used for psoriasis.. To examine the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on cultured normal keratinocytes (NHK) and compared its effect with those of various vitamin D3 analogues.. Cell proliferation of NHK cells was analyzed by MTS, BrdU and 3H-thymidine incorporation. The expression of involucrin, transglutaminase 1, keratin 5 and keratin 1 was investigated by western blot and PCR amplification and quantitative assay. Furthermore, we performed cornified cell envelope (CE) formation assay.. 1,25(OH)2D3, tacalcitol, calcipotriol, and maxacalcitol decreased NHK cell proliferation in a concentration-dependent manner and the maximal effect was observed at 10(-7) M. There was no significant difference in the anti-proliferative effect among the active vitamin D3 analogues. The expression of involucrin and transglutaminase 1 were induced by 1,25(OH)2D3 and its analogues in mRNA and protein levels. CE formation was also induced by 1,25(OH)2D3 and its analogues. There was no significant difference in the potency among these chemicals. Keratin 5 and 1 expression was not altered by these active vitamin D3 analogues.. The present study demonstrated that active vitamin D3 analogues, tacalcitol, calcipotriol, and maxacalcitol, suppress keratinocyte proliferation and induce differentiation with similar potency.

Topics: Calcitriol; Cell Differentiation; Cell Division; Cells, Cultured; Dermatologic Agents; Dihydroxycholecalciferols; Humans; Keratinocytes; Protein Precursors; Transglutaminases

We report in this study that proliferation inhibition of SCC13 cells by calcipotriol was possibly mediated by its inhibitory effect on autocrine activation of EGF receptor. Based on MTT assay, PCNA staining, DAPI staining, and involucrin immunocytochemical staining, we showed that calcipotriol inhibited cell growth and stimulated differentiation but did not induce apoptosis. Western blot analysis of concanavalin-A-bound fraction demonstrated that calcipotriol specifically dephosphorylated 170- and 66-kDa polypeptides from 8 h posttreatment and complete dephosphorylation was observed at 12 h posttreatment. The 170- and 66-kDa polypeptides were confirmed as EGF receptor and Shc, respectively. Calcipotriol-mediated EGF receptor dephosphorylation required the presence of extracellular calcium. Similar kinetics of the dephosphorylation was also observed in HaCaT cells cultured in medium of high calcium concentration. By BrdU labeling, we also showed calcium dependency of calcipotriol for the inhibition of cell proliferation. Therefore, EGF receptor deactivation by calcipotriol might be a mechanism of action for the inhibition of cell proliferation and the stimulation of differentiation in SCC13 cell and HaCaT cells.

Topics: Adaptor Proteins, Signal Transducing; Adaptor Proteins, Vesicular Transport; Antineoplastic Agents; Apoptosis; Autocrine Communication; Blotting, Western; Bromodeoxyuridine; Calcitriol; Calcium; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Cell Line; ErbB Receptors; Fluorescent Dyes; Humans; Keratinocytes; Phosphorylation; Proliferating Cell Nuclear Antigen; Protein Precursors; Proteins; Shc Signaling Adaptor Proteins; Signal Transduction; Src Homology 2 Domain-Containing, Transforming Protein 1; Tetrazolium Salts; Thiazoles

The biologically active vitamin D analog calcipotriol is effective and safe in the topical treatment of psoriasis, but its exact mechanism of action is unknown.. We investigated expression of 1,25-dihydroxyvitamin D3 receptors, markers for inflammation (CD1a, CD4, CD8, CD11b, CD15; NAP-1/interleukin-8; 55 kd tumor necrosis factor-receptor; intercellular adhesion molecule-1; HLA-DR), proliferation (proliferating cell nuclear antigen, Ki-67), and differentiation (transglutaminase K; involucrin; cytokeratin 16) in psoriatic skin during topical calcipotriol treatment.. For immunohistochemical staining we used the labeled avidin-biotin technique on cryostat-cut sections.. We found a significant increase of 1,25-dihydroxyvitamin D3 receptor expression in epidermal basal keratinocytes of lesional psoriatic skin during calcipotriol treatment. In all patients analyzed, effects on proliferation and differentiation of epidermal keratinocytes were stronger than effects on dermal inflammation. Effects on inflammation were more pronounced in the epidermal than in the dermal compartment.. Our findings indicate that analogs of 1,25-dihydroxyvitamin D3 upregulate their corresponding receptor in human keratinocytes in vivo. This mechanism may be important in the therapeutic efficacy of vitamin D analogs in psoriasis. The differential therapeutic effects in the epidermal and dermal skin compartments may be due to a reduced bioavailability of calcipotriol in the dermal compartment.

Topics: Administration, Cutaneous; Antigens, CD; Antigens, CD1; Biological Availability; Calcitriol; CD11 Antigens; CD4 Antigens; CD8 Antigens; Cell Differentiation; Cell Division; Dermatologic Agents; Epidermis; Gene Expression Regulation; HLA-DR Antigens; Humans; Immunoenzyme Techniques; Immunohistochemistry; Intercellular Adhesion Molecule-1; Interleukin-8; Keratinocytes; Keratins; Lewis X Antigen; Male; Proliferating Cell Nuclear Antigen; Protein Precursors; Psoriasis; Receptors, Calcitriol; Receptors, Interleukin; Receptors, Interleukin-8A; Receptors, Tumor Necrosis Factor; Skin; Transglutaminases; Tumor Necrosis Factor-alpha; Up-Regulation