Non-Muscle-Invasive Bladder Carcinoma with Respect to Basal Versus Luminal Keratin Expression

Non-muscle-invasive bladder cancer (NMIBC) consists of transcriptional subtypes that are distinguishable from those of muscle-invasive cancer. We aimed to identify genetic signatures of NMIBC related to basal (K5/6) and luminal (K20) keratin expression. Based on immunohistochemical staining, papillary high-grade NMIBC was classified into K5/6-only (K5/6High-K20Low), K20-only (K5/6Low-K20High), double-high (K5/6High-K20High), and double-low (K5/6Low-K20Low) groups (n = 4 per group). Differentially expressed genes identified between each group using RNA sequencing were subjected to functional enrichment analyses. A public dataset was used for validation. Machine learning algorithms were implemented to predict our samples against UROMOL subtypes. Transcriptional investigation demonstrated that the K20-only group was enriched in the cell cycle, proliferation, and progression gene sets, and this result was also observed in the public dataset. The K5/6-only group was closely regulated by basal-type gene sets and showed activated invasive or adhesive functions. The double-high group was enriched in cell cycle arrest, macromolecule biosynthesis, and FGFR3 signaling. The double-low group moderately expressed genes related to cell cycle and macromolecule biosynthesis. All K20-only group tumors were classified as UROMOL “class 2” by the machine learning algorithms. K5/6 and K20 expression levels indicate the transcriptional subtypes of NMIBC. The K5/6Low-K20High expression is a marker of high-risk NMIBC.

Aggregatibacter actinomycetemcomitans Biofilm Reduces Gingival Epithelial Cell Keratin Expression in an Organotypic Gingival Tissue Culture Model

Epithelial cells express keratins, which are essential for the structural integrity and mechanical strength of the cells. In the junctional epithelium (JE) of the tooth, keratins such as K16, K18, and K19, are expressed, which is typical for non-differentiated and rapidly dividing cells. The expression of K17, K4, and K13 keratins can be induced by injury, bacterial irritation, smoking, and inflammation. In addition, these keratins can be found in the sulcular epithelium and in the JE. Our aim was to estimate the changes in K4, K13, K17, and K19 expression in gingival epithelial cells exposed to Aggregatibacter actinomycetemcomitans. An organotypic gingival mucosa and biofilm co-culture was used as a model system. The effect of the biofilm after 24 h was assessed using immunohistochemistry. The structure of the epithelium was also studied with transmission electron microscopy (TEM). The expression of K17 and K19, as well as total keratin expression, decreased in the suprabasal layers of epithelium, which were in close contact with the A. actinomycetemcomitans biofilm. The effect on keratin expression was biofilm specific. The expression of K4 and K13 was low in all of the tested conditions. When stimulated with the A. actinomycetemcomitans biofilm, the epithelial contact site displayed a thick necrotic layer on the top of the epithelium. The A. actinomycetemcomitans biofilm released vesicles, which were found in close contact with the epithelium. After A. actinomycetemcomitans irritation, gingival epithelial cells may lose their resistance and become more vulnerable to bacterial infection.