ABSTRACT
In inflammation-associated carcinogenesis, COX-2 is markedly overexpressed, resulting in accumulation of various prostaglandins. 15-deoxy-Δ 12,14 -prostaglandin J 2 (15d-PGJ2 ) is one of the terminal products of COX-2-catalyzed arachidonic acid catabolism with oncogenic potential. Epithelial-to-mesenchymal transition (EMT) is a process by which epithelial cells lose their polarity and adhesiveness, and thereby gain migratory and invasive properties. Treatment of human breast cancer MCF-7 cells with 15d-PGJ2 induced EMT as evidenced by increased expression of Snail and ZEB1, with concurrent down-regulation of E-cadherin. Nuclear extract from 15d-PGJ2 -treated MCF-7 cells showed the binding of Snail and ZEB1 to E-box sequences present in the E-cadherin promoter, which accounts for repression of E-catherin expression. Unlike 15d-PGJ2 , its non-electrophilic analogue 9,10-dihydro-15d-PGJ2 failed to induce EMT, suggesting that the α,β-unsaturated carbonyl group located in the cyclopentenone ring of 15d-PGJ2 is essential for its oncogenic function. Notably, the mRNA level of interleukin-8 (IL-8)/CXCL8 was highly elevated in 15d-PGJ 2 -stimulated MCF-7 cells. 15d-PGJ2 -induced up-regulation of IL-8/CXCL8 expression was abrogated by silencing of Snail short interfering RNA. Treatment of normal fibroblast with conditioned medium obtained from cultures of MCF-7 cells undergoingEMT induced the expression of activated fibroblast marker proteins, α-smooth muscle actin and fibroblasts activation protein-α.Co-culture of normal fibroblasts with 15d-PGJ2 -stimulated MCF-7 cells also activated normal fibroblast cells to cancer associated fibroblasts. Taken together, above findings suggest that 15d-PGJ2 induces EMT through up-regulation of Snail expression and subsequent production of CXCL8 as a putative activator of fibroblasts, which may contribute to tumor-stroma interaction in inflammatory breast cancer microenvironment.
ABSTRACT
Purpose@#The purpose of this study is to compare the shear bond strength of 3D printing denture base resin according to surface treatment of artificial teeth. @*Materials and methods@#3D printing denture base resin was fabricated as specimens using 3D printer. The experimental group divided the surface treatment of artificial teeth into five groups according to the application of sandblasting and primer (n=10). Shear bond strengths between denture base and artificial teeth were measured by universal testing machine. All measurements were analyzed by one-way ANOVA and Turkey test (α=.05). Fracture mode of each specimen was analyzed. Microscopic evaluation was conducted by using a scanning electron microscope. @*Results@#Unsurfaced treated group represented the lowest value. The primer groups had significantly higher result values (P<.05). Most specimens of the primer groups had cohesive failure. @*Conclusion@#In 3D printing denture base resin group, mechanical and chemical surface treatment of artificial teeth has increased the shear bond strength. Therefore, if dentures are produced using 3D printing, proper mechanical and chemical treatment of artificial teeth is necessary for adhesion of dentures and artificial teeth.