Chen Tu

microRNA-216b inhibits cell proliferation and migration in human melanoma by targeting FOXM1 in vitro and in vivo†

MicroRNAs (miRNAs) play an increasingly important role in cancer growth by coordinately suppressing genes that control cell migration, proliferation, and invasion. The above results can be achieved through the regulation of gene expression by miRNAs by suppressing translation or the direct sequence‐specific degradation of the targeted mRNA. In the present study, we indicate that the expression of miR‐216b could be effectively repressed both in human melanoma tissues through a comparison with primary melanoma and in human melanoma cell lines through a comparison with a normal human keratinocyte line. Moreover, miR‐216b induced a clear decrease in melanoma cell proliferation and migration in vitro. Forkhead box M1 (FOXM1) was confirmed as a target gene of miR‐216b, and the overexpression of miR‐216b markedly repressed the luciferase activity of reporter plasmids containing the FOXM1 3′‐UTR (untranslated region). Furthermore, miR‐216b suppressed melanoma cell growth in nude mice in vivo, with the effects of miR‐216b overexpression on melanoma cell growth and proliferation reversed by FOXM1 overexpression. The results demonstrated that miR‐216b is a tumor suppressor in melanoma, identified the FOXM1 signaling pathway as a target of miR‐216b action, and suggested a potential therapeutic role for miR‐216b in melanoma.

Wnt/β-Catenin and Wnt5a/Ca Pathways Regulate Proliferation and Apoptosis of Keratinocytes in Psoriasis Lesions.

Background/Aims: Wnt5a is overexpressed in psoriasis lesions, however the mechanism by which Wnt5a is involved in the pathogenesis of psoriasis is not clear. To address this, the expression of Wnt5a in psoriatic lesions and its effect on keratinocyte cell proliferation and apoptosis was examined in vitro. Methods: The expression levels of WNT5A, and genes encoding its receptors frizzled2 (FZD2) and frizzled5 (FZD5) were examined in samples obtained from individuals with psoriasis and healthy controls. Knockdown of Wnt5a with short interfering (si)RNAs was performed in cultured HaCaT keratinocytes and normal human keratinocytes (NHK), and the expression of Wnt5a, protein kinase C (PKC), and β-catenin were determined, and cell cycle activity, proliferation and apoptosis were assessed. Results: The expression of WNT5A, FZD2 and FZD5 mRNA and protein were increased in psoriatic lesions. Wnt5a knockdown suppressed proliferation and induced apoptosis in HaCaT and NHK cells. Additionally, expression of PCNA, MKI67, CCND1, BCL2, CTNNB1, and genes encoding PKC and survivin were downregulated, whereas CASP3 was upregulated. The mRNA levels of the Wnt pathway inhibitors DKK1 and SFRP1 were upregulated, Western blotting analyses demonstrated reduction in β-catenin and PKC protein levels. Conclusion: Knockdown of Wnt5a suppresses the proliferation of keratinocytes and induces apoptosis by inhibiting the Wnt/β-catenin or Wnt5a/Ca2+ pathways.

Wnt5a is involved in the pathogenesis of cutaneous lichen planus.

Cutaneous lichen planus (CLP) is a chronic inflammatory and immune‐mediated disease. Wnt5a is one of the most extensively studied Wnt proteins, and has important functions in stimulating inflammation, cell proliferation, cell fate determination and cell differentiation. Wnt5a expression in CLP has not been comprehensively studied to date.

Failure of rapamycin in the treatment of multiple haemangiomas associated with Maffucci syndrome.

Maffucci syndrome is a rare, nonhereditary, congenital, mesodermal dysplasia presenting as multiple enchondromas and haemangiomas, which was first described in 1881. Cartilaginous and vascular lesions are exclusively or predominantly unilateral, and may progress to malignancy. Mutant isocitrate dehydrogenase (IDH)1 or IDH2 pathways can substantially contribute to tumourigenesis. There is currently no effective medical treatment for the vascular lesions associated with Maffucci syndrome, although Riou et al. reported a case with spindle-cell haemangioma in 2012, which was successfully treated with low doses of rapamycin. We present a case of Maffucci syndrome with vascular lesions presenting as exclusively cavernous haemangioma, which was not responsive to rapamycin treatment.

Hailey–Hailey disease: investigation of a possible compensatory SERCA2 up-regulation and analysis of SPCA1, p63, and IRF6 expression

Hailey–Hailey disease (HHD) is caused by heterozygous mutations in the ATP2C1 gene, encoding the secretory pathway Ca2+ ATPase1 (SPCA1). SPCA1 and sarco/endoplasmic reticulum Ca2+ ATPase2 (SERCA2) encoded by ATP2A2 are two essential calcium pumps needed for Ca2+ homeostasis maintenance in keratinocytes. ATP2A2 mutations cause another hereditary skin disorder, Darier’s disease (DD). Previously, the compensatory expression of SPCA1 for SERCA2 insufficiency in DD was demonstrated, but it is not known whether a similar compensatory mechanism exists in HHD. Additionally, little is known about the role of p63 and interferon regulatory factor 6 (IRF6), two important regulatory factors involved in keratinocyte proliferation and differentiation, in HHD. Here, we used the skin biopsy samples from patients with HHD and human primary keratinocytes transfected with ATP2C1 siRNA to search for potential pathogenic mechanisms in HHD. We observed normal SERCA2 levels, but reduced p63, and increased IRF6 levels in HHD epidermal tissues and SPCA1-deficient keratinocytes. This suggests that there is no compensatory mechanism by SERCA2 for the SPCA1 deficiency in HHD. Moreover, the abnormal expression of p63 and IRF6 appears to be related to SPCA1 haploinsufficiency, with down-regulation of p63 probably resulting from IRF6 overexpression in HHD. We speculate that a novel pathogenic mechanism involving SPCA1, p63, and IRF6 may play a role in the skin lesions occurring in HHD.

Lipopolysaccharide induces TREM-1-dependent HIF-1α expression in human keratinocyte cell line.

Bacterial infection is an important factor that can trigger and exacerbate psoriasis. The protein triggering receptor expressed on myeloid cells type‐1 (TREM‐1) is overexpressed in psoriasis and decreased after a successful treatment. Hypoxia inducible factor‐1α (HIF‐1α), subunit of the transcription factor HIF‐1, has participated in angiogenesis and inflammation in psoriasis. Increased expressions of TREM‐1 and HIF‐1α are associated with the infection of microbial pathogens. However, the association between TREM‐1 and HIF‐1α still needs to be elucidated. Results of immunofluorescence showed an overexpression of TREM‐1 and HIF‐1α in HaCaT keratinocytes exposed to 1 µg/mL of lipopolysaccharide (LPS). Particularly, silencing of TREM‐1 expression by siRNA suppressed the inducible effect of LPS on phosphoinositide 3‐kinase (PI3 K)/Akt, the critical transduction mediator, and HIF‐1α. Furthermore, the PI3 K inhibitor wortmannin effectively blocked the increased level of HIF‐1α induced by LPS. However, there was no significant change in LPS‐induced expression of TREM‐1. Expressions of TREM‐1, HIF‐1α, and phosphorylated Akt proteins were further examined by real‐time PCR and Western blot, respectively. Our data suggest that TREM‐1 and HIF‐1α are expressed on keratinocytes and could be upregulated by bacterial infection. Moreover, LPS‐induced TREM‐1 has an ability to mediate the expression of HIF‐1α in HaCaT cells through the PI3 K/Akt pathway. Our study provides new insights into the possible mechanism of TREM‐1 and HIF‐1α in psoriasis.

Expression of Skin Barrier Protein Filaggrin in Skin Diseases without Atopic Dermatitis

The epidermis represents an essential barrier versus a broad range of exogenous stimuli. To form a functional epidermis, keratinocytes express filaggrin which plays a vital role in atopic dermatitis. However the relationship between filaggrin and other skin diseases remains unknown. In our study we chose 5 different common skin diseases and analyzed the expression of filaggrin in the skin using immunohistochemistry. Imiquimod (IMQ)-induced mouse model was used for detecting the filaggrin level and barrier function. The results indicated that the expression of filaggrin is reduced in psoriasis compared to the other skin diseases. Furthermore in vivo study showed that the skin barrier is defected with a decreased expression of filaggrin in IMQ-induced psoriasis mouse model, which is accompanied with an increased level of IL-17/IL-23. In conclusion, the defective skin barrier is involved in the development of psoriasis in human and mice with a reduced expression of filaggrin which may be regulated by the increased level of IL-17/IL-23 in the skin.

MicroRNA-378 regulates epithelial-mesenchymal transition and metastasis of melanoma by inhibiting FOXN3 expression through the Wnt/β-catenin pathway: miR-378 regulates EMT of melanoma

MicroRNAs (miRNAs) participate in the development and progression of melanoma. However, while dysregulation of microRNA‐378 (miR‐378) has been seen in various cancer types, its clinical importance and function in melanoma are poorly elucidated. In this work, miR‐378 expression in melanoma and in adjacent non‐cancerous tissue was evaluated with a quantitative real‐time polymerase chain reaction. A series of assays (wound healing, Transwell, and nude mouse subcutaneous tumor model) were used to investigate the implications of abnormal miR‐378 regulation on melanoma cell migration and invasion in vitro, and on tumorigenicity in vivo. Prediction and conformation of the miR‐378 target gene was undertaken using bioinformatic analysis and luciferase reporter system. Expression of miR‐378 was often increased in melanoma, and shown to potentiate its migration, invasion, and tumorigenicity. miR‐378 acted, at least partially, through inhibition of the potential target FOXN3 and via Wnt/β‐catenin pathway activation. The findings indicate that miR‐378 triggers melanoma development and progression. This miRNA could be a novel diagnostic and prognostic biological marker and provide utility for targeted treatment of melanoma.

Atrichia with Papular Lesions in a Chinese Family Caused by Novel Compound Heterozygous Mutations and Literature Review

Background: Congenital atrichia with papular lesions (APL) is characterized by complete absence of body hair shortly after birth, along with papules, and caused by mutations in the hairless gene (HR). Objective: To investigate whether APL with HR mutations might also be found among patients in non-consanguineous Chinese families and to discuss the phenotypic variations with the same mutations. Methods: DNA sequencing of the HR was performed in the Chinese pedigree and in 100 controls. Results: A nonsense mutation c.T2265A in the patient and his father as well as a 2bp deletion (3482delCT) in the patient and his mother were detected. Conclusion: Our study identified the first mutation in exon 10 in HR as well as the second novel compound heterozygous mutations in a Chinese family, also adding new variants to the knowledge of HR mutations in APL. Phenotypic heterogeneity in congenital atrichia might be subject to the founder genes or modifier genes.