Cytokeratin 15 is a novel and independent predictor of poor outcome in luminal B HER2-negative breast carcinomas.

Cytokeratin 15 (CK15) has been described as a stem cell marker in human organs and its expression is seen in breast tissue. CK15 expression is associated with aggressive features in endometrial and oesophageal cancers, but data on the breast are lacking. This study aims to investigate the clinicopathological associations and prognostic significance of CK15 in breast carcinomas. A multi-institute cohort of breast carcinomas were retrieved. Clinicopathological and outcome data were obtained and compared with immunohistochemical expression CK15 and a panel of biomarkers. In total, 1,476 cases were included, with an expression rate of 3.5%, preferentially expressed in luminal subtypes (p=0.024), with luminal B carcinomas being the highest (4.7%), as opposed to basal-like (1%) and HER2-overexpressed carcinomas (0%). Except for nodal stage (p=0.013) and nodal metastasis (p=0.048), oestrogen (p=0.035) and progesterone receptor (p=0.001) positivity, there were no associations with other clinicopathological parameters. A trend was observed with shorter breast cancer specific survival (BCSS) in CK15-positive luminal B carcinomas (p=0.062). On further subgroup multivariate analysis of luminal B HER2-negative carcinomas, CK15 expression exhibited robust correlation with shorter BCSS (HR=9.004, p=0.001) and disease-free survival (HR=7.085, p<0.001). Restricted to luminal breast carcinomas, specifically luminal B HER2-negative, CK15 is demonstrated to be a robust independent predictor of higher risk of recurrence and shorter survival, with potential as a clinical prognostic marker and an exclusive stem cell marker for this subgroup of carcinomas.

Upregulation of caveolae-associated structural proteins in the hair follicle bulge of lichen planopilaris and frontal fibrosing alopecia.

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary cicatricial alopecia that cause a major impact on quality of life due to irreversible hair loss and symptoms as itching, burning and pain. They are characterized by permanent loss of hair follicle stem cells (HFSCs) by pathomechanisms still poorly understood, resulting in poor efficacy of currently available treatments. Caveolae are flask-shaped lipid rafts invaginated within the plasma membrane of multiple cell types. Although their role in the HF physiology and pathophysiology is relatively unknown, we have previously demonstrated that the primary structural component of caveolae (caveolin-1 or Cav1) is upregulated in FFA. Thus, we propose to investigate the expression and localization of caveolae-associated structural proteins (Cav1, Cav2, and Cavin-1) and HFSCs (identified by K15) in both LPP and FFA. We analyzed 4 patients with LPP biopsied in affected and non-affected (NA) scalp, 4 patients with FFA biopsied in affected scalp and 4 healthy controls. Affected scalp of LPP and FFA demonstrated increased levels of Cav1 and Cavin-1 compared with HC and LPP-NA. Moreover, Cav1, Cav2 and Cavin1 all exhibit high colocalization with K15 and their expression appears to be negatively correlated, supporting the hypothesis that these proteins are important players in LPP/FFA and may serve as therapeutic targets in future treatments.

Following the p63/Keratin5 basal cells in the sensory and non-sensory epithelia of the vomeronasal organ.

The vomeronasal organ (VNO) is a part of the accessory olfactory system, which detects pheromones and chemical factors that trigger a spectrum of sexual and social behaviors. The vomeronasal epithelium (VNE) shares several features with the epithelium of the main olfactory epithelium (MOE). However, it is a distinct neuroepithelium populated by chemosensory neurons that differ from the olfactory sensory neurons in cellular structure, receptor expression, and connectivity. The vomeronasal organ of rodents comprises a sensory epithelium (SE) and a thin non-sensory epithelium (NSE) that morphologically resembles the respiratory epithelium. Sox2-positive cells have been previously identified as the stem cell population that gives rise to neuronal progenitors in MOE and VNE. In addition, the MOE also comprises p63 positive horizontal basal cells, a second pool of quiescent stem cells that become active in response to injury. Immunolabeling against the transcription factor p63, Keratin-5 (Krt5), Krt14, NrCAM, and Krt5Cre tracing experiments highlighted the existence of horizontal basal cells distributed along the basal lamina of SE of the VNO. Single cell sequencing and genetic lineage tracing suggest that the vomeronasal horizontal basal cells arise from basal progenitors at the boundary between the SE and NSE proximal to the marginal zones. Moreover, our experiments revealed that the NSE of rodents is, like the respiratory epithelium, a stratified epithelium where the p63/Krt5+ basal progenitor cells self-replicate and give rise to the apical columnar cells facing the lumen of the VNO.

High keratin 15 expression reflects favorable prognosis in early cervical cancer patients.

OBJECTIVE: Keratin 15 (KRT15) exhibits inconsistent prognostic roles in different cancers, and its prognostic value in early cervical cancer patients who receive tumor resection remains unknown. This study aimed to assess the relationship of KRT15 expression with prognosis in these patients. METHODS: Totally, 147 early cervical cancer patients who received tumor resection were reviewed in this retrospective study. KRT15 was detected in formalin-fixed paraffin-embedded tumor tissue by immunohistochemistry (IHC). KRT15 IHC scores were computed by multiplying the percentage of positively stained cells (scored as 0-4) and corresponding staining intensity (scored as 0-3), ranging from 0 to 12. RESULTS: Elevated KRT15 IHC score was linked with moderate to well differentiation (P = 0.005), tumor size ≤ 4 cm (P = 0.017), and International Federation of Gynecology and Obstetrics (FIGO) stage Ia/Ib (P < 0.001). KRT15 IHC score was inversely associated with adjuvant radiotherapy (P = 0.025) and adjuvant chemotherapy (P = 0.016). KRT15 IHC score ≥ 1 was linked with increased disease-free survival (DFS) (P = 0.003) and overall survival (OS) (P = 0.049). Meanwhile, KRT15 IHC score ≥ 1 independently predicted increased DFS (hazard ratio = 0.213, P = 0.017), but not OS (P > 0.05). KRT15 IHC score ≥ 3 and KRT15 IHC score ≥ 6 could not predict DFS or OS (all P > 0.05). By subgroup analyses, KRT15 IHC score ≥ 1 forecasted favorable DFS in patients with age > 45 years, human papillomavirus-positive, squamous carcinoma, and tumor size ≤ 4 cm (all P < 0.05). KRT15 IHC score ≥ 1 and KRT15 IHC score ≥ 3 predicted ascended DFS in patients without adjuvant radiotherapy or adjuvant chemotherapy (all P < 0.05). CONCLUSION: High KRT15 expression reflects favorable tumor features and longer survival in early cervical cancer patients who receive tumor resection.

Keratin 15 protects against cigarette smoke-induced epithelial mesenchymal transformation by MMP-9.

BACKGROUND: Chronic obstructive pulmonary disease (COPD), a chronic inflammatory lung disease, is a leading cause of morbidity and mortality worldwide. Prolonged cigarette smoking (CS) that causes irreversible airway remodeling and significantly reduces lung function is a major risk factor for COPD. Keratin15+ (Krt15+) cells with the potential of self-renewal and differentiation properties have been implicated in the maintenance, proliferation, and differentiation of airway basal cells; however, the role of Krt15 in COPD is not clear. METHODS: Krt15 knockout (Krt15-/-) and wild-type (WT) mice of C57BL/6 background were exposed to CS for six months to establish COPD models. Krt15-CrePGR;Rosa26-LSL-tdTomato mice were used to trace the fate of the Krt15+ cells. Hematoxylin and eosin (H&E) and Masson stainings were performed to assess histopathology and fibrosis, respectively. Furthermore, lentivirus-delivered short hairpin RNA (shRNA) was used to knock down KRT15 in human bronchial epithelial (HBE) cells stimulated with cigarette smoke extract (CSE). The protein expression was assessed using western blot, immunohistochemistry, and enzyme-linked immunosorbent assay. RESULTS: Krt15-/- CS mice developed severe inflammatory cell infiltration, airway remodeling, and emphysema. Moreover, Krt15 knockout aggravated CS-induced secretion of matrix metalloproteinase-9 (MMP-9) and epithelial-mesenchymal transformation (EMT), which was reversed by SB-3CT, an MMP-9 inhibitor. Consistent with this finding, KRT15 knockdown promoted MMP-9 expression and EMT progression in vitro. Furthermore, Krt15+ cells gradually increased in the bronchial epithelial cells and were transformed into alveolar type II (AT2) cells. CONCLUSION: Krt15 regulates the EMT process by promoting MMP-9 expression and protects the lung tissue from CS-induced injury, inflammatory infiltration, and apoptosis. Furthermore, Krt15+ cells transformed into AT2 cells to protect alveoli. These results suggest Krt15 as a potential therapeutic target for COPD.

Upregulated keratin 15 links to the occurrence of lymphovascular invasion, stromal cervical invasion as well as unfavorable survival profile in endometrial cancer patients.

Keratin 15 (KRT15) overexpression links with tumor initiation, metastasis, and poor survival in several solid carcinomas. While its clinical relevance is scarcely reported in endometrial cancer (EC). Therefore, the current study aimed to investigate the abnormal expression of KRT15 and its correlation with clinical characteristics, survival in EC patients. Totally, 135 surgical EC patients were enrolled. KRT15 protein expression in formalin-fixed and paraffin-embedded tumor and adjuvant tissues was detected by immunohistochemical staining; meanwhile, KRT15 mRNA expression in fresh-frozen tumor and adjacent tissues was detected by reverse transcription-quantitative polymerase chain reaction. KRT15 protein and mRNA expressions were higher in tumor tissue compared with adjacent tissue (both P < .001). Elevated KRT15 protein expression was correlated with the occurrence of lymphovascular invasion (P = .010) and more advanced International Federation of Gynecology and Obstetrics stage (P = .018); meanwhile, elevated KRT15 mRNA expression was linked with more advanced International Federation of Gynecology and Obstetrics stage (P = .038) and marginally associated with the occurrence of stromal cervical invasion (P = .052). Besides, KRT15 protein and mRNA expressions were not correlated with other clinical features (all P > .05). KRT15 protein high was marginally correlated with poor accumulating disease-free survival (DFS) (P = .091) and overall survival (OS) (P = .059); meanwhile, the correlation of KRT15 mRNA expression with accumulating DFS (P = .212) and OS (P = .092) was even weaker. However, multivariate Cox's regressions showed that tumor KRT15 protein (high vs low) was independently correlated with poor DFS (P = .045) and OS (P = .043). KRT15 is abnormally increased in EC tissue, meanwhile, its upregulation links to the occurrence of lymphovascular invasion, stromal cervical invasion, and poor prognosis in EC patients.

KRT15 promotes colorectal cancer cell migration and invasion through ß-catenin/MMP-7 signaling pathway.

KRT15 has been reported to act as an oncogene in colorectal cancer. However, whether KRT15 promotes colorectal cancer migration and invasion remain unclear. In this study, western blot and qRT-PCR assay were used to determine the expression of KRT15 in colorectal cancer cells. Wound-healing and transwell migration assay were performed to assess the migration of colorectal cancer cells. Matrigel transwell invasion assay was employed to examine the invasion of colorectal cancer cells. We found that KRT15 was highly expressed in colorectal cancer cells. Ectopic expression of KRT15 dramatically promoted colorectal cancer cell migration and invasion. Conversely, silencing KRT15 remarkably suppressed the migration and invasion of colorectal cancer cells. Importantly, we found that MMP-7 was crucial for KRT15-induced migration and invasion of colorectal cancer cells. Knockdown of MMP-7 significantly diminished the migration and invasion induced by KRT15; overexpression of MMP-7 almost completely rescued the inhibitory effects of KRT15 shRNAs on colorectal cancer cell migration and invasion. In addition, by gain- and loss-of function, we confirmed that ß-catenin was responsible for the increased expression of MMP-7 induced by KRT15 colorectal cancer cell lines. In conclusion, KRT15 promotes migration and invasion of colorectal cancer cell at least partly through ß-catenin/MMP7 signaling pathway, suggesting KRT15 is a potential therapeutic target for patients with metastatic colorectal cancer.

Local tissue interactions govern pLL patterning in medaka.

Vertebrate organs are arranged in a stereotypic, species-specific position along the animal body plan. Substantial morphological variation exists between related species, especially so in the vastly diversified teleost clade. It is still unclear how tissues, organs and systems can accommodate such diverse scaffolds. Here, we use the distinctive arrangement of neuromasts in the posterior lateral line (pLL) system of medaka fish to address the tissue-interactions defining a pattern. We show that patterning in this peripheral nervous system is established by autonomous organ precursors independent of neuronal wiring. In addition, we target the keratin 15 gene to generate stuck-in-the-midline (siml) mutants, which display epithelial lesions and a disrupted pLL patterning. By using siml/wt chimeras, we determine that the aberrant siml pLL pattern depends on the mutant epithelium, since a wild type epithelium can rescue the siml phenotype. Inducing epithelial lesions by 2-photon laser ablation during pLL morphogenesis phenocopies siml genetic mutants and reveals that epithelial integrity defines the final position of the embryonic pLL neuromasts. Our results using the medaka pLL disentangle intrinsic from extrinsic properties during the establishment of a sensory system. We speculate that intrinsic programs guarantee proper organ morphogenesis, while instructive interactions from surrounding tissues facilitates the accommodation of sensory organs to the diverse body plans found among teleosts.

Defining a Role for G-Protein Coupled Receptor/cAMP/CRE-Binding Protein Signaling in Hair Follicle Stem Cell Activation.

Manipulation of adrenergic signaling has been shown experimentally and clinically to affect hair follicle growth. In this study, we provide direct evidence that canonical cAMP/CRE-binding protein signaling through adrenergic receptors can regulate hair follicle stem cell (HFSC) activation and hair cycle. We found that CRE-binding protein activation is regulated through the hair cycle and coincides with HFSC activation. Both isoproterenol and procaterol, agonists of adrenergic receptors, show the capacity to activate the hair cycle in mice. Furthermore, deletion of ADRB2 receptor, which is thought to mediate sympathetic nervous system regulation of HFSCs, was sufficient to block HFSC activation. Downstream, stimulation of adenylyl cyclase with forskolin or inhibition of phosphodiesterase to increase cAMP accumulation or direct application of cAMP was each sufficient to promote HFSC activation and accelerate initiation of hair cycle. Genetic induction of a Designer Receptors Exclusively Activated by Designer Drug allele showed that G-protein coupled receptor/GαS stimulation, specifically in HFSCs, promoted the activation of the hair cycle. Finally, we provide evidence that G-protein coupled receptor/CRE-binding protein signaling can potentially act on HFSCs by promoting glycolytic metabolism, which was previously shown to stimulate HFSC activation. Together, these data provide mechanistic insights into the role of sympathetic innervation on HFSC function.

Accelerated complete human skin architecture restoration after wounding by nanogenerator-driven electrostimulation.

BACKGROUND: Electrostimulation (ES) therapy for wound healing is limited in clinical use due to barriers such as cumbersome equipment and intermittent delivery of therapy. METHODS: We adapted a human skin xenograft model that can be used to directly examine the nanogenerator-driven ES (NG-ES) effects on human skin in vivo-an essential translational step toward clinical application of the NG-ES technique for wound healing. RESULTS: We show that NG-ES leads to rapid wound closure with complete restoration of normal skin architecture within 7 days compared to more than 30 days in the literature. NG-ES accelerates the inflammatory phase of wound healing with more rapid resolution of neutrophils and macrophages and enhances wound bed perfusion with more robust neovascularization. CONCLUSION: Our results support the translational evaluation and optimization of the NG-ES technology to deliver convenient, efficient wound healing therapy for use in human wounds.

Fine-tuned repression of Drp1-driven mitochondrial fission primes a 'stem/progenitor-like state' to support neoplastic transformation.

Gene knockout of the master regulator of mitochondrial fission, Drp1, prevents neoplastic transformation. Also, mitochondrial fission and its opposing process of mitochondrial fusion are emerging as crucial regulators of stemness. Intriguingly, stem/progenitor cells maintaining repressed mitochondrial fission are primed for self-renewal and proliferation. Using our newly derived carcinogen transformed human cell model, we demonstrate that fine-tuned Drp1 repression primes a slow cycling 'stem/progenitor-like state', which is characterized by small networks of fused mitochondria and a gene-expression profile with elevated functional stem/progenitor markers (Krt15, Sox2 etc) and their regulators (Cyclin E). Fine tuning Drp1 protein by reducing its activating phosphorylation sustains the neoplastic stem/progenitor cell markers. Whereas, fine-tuned reduction of Drp1 protein maintains the characteristic mitochondrial shape and gene-expression of the primed 'stem/progenitor-like state' to accelerate neoplastic transformation, and more complete reduction of Drp1 protein prevents it. Therefore, our data highlights a 'goldilocks' level of Drp1 repression supporting stem/progenitor state dependent neoplastic transformation.

Conditional Deletion of AP-2ß in the Periocular Mesenchyme of Mice Alters Corneal Epithelial Cell Fate and Stratification.

The cornea is an anterior eye structure specialized for vision. The corneal endothelium and stroma are derived from the periocular mesenchyme (POM), which originates from neural crest cells (NCCs), while the stratified corneal epithelium develops from the surface ectoderm. Activating protein-2ß (AP-2ß) is highly expressed in the POM and important for anterior segment development. Using a mouse model in which AP-2ß is conditionally deleted in the NCCs (AP-2ß NCC KO), we investigated resulting corneal epithelial abnormalities. Through PAS and IHC staining, we observed structural and phenotypic changes to the epithelium associated with AP-2ß deletion. In addition to failure of the mutant epithelium to stratify, we also observed that Keratin-12, a marker of the differentiated epithelium, was absent, and Keratin-15, a limbal and conjunctival marker, was expanded across the central epithelium. Transcription factors PAX6 and P63 were not observed to be differentially expressed between WT and mutant. However, growth factor BMP4 was suppressed in the mutant epithelium. Given the non-NCC origin of the epithelium, we hypothesize that the abnormalities in the AP-2ß NCC KO mouse result from changes to regulatory signaling from the POM-derived stroma. Our findings suggest that stromal pathways such as Wnt/ß-Catenin signaling may regulate BMP4 expression, which influences cell fate and stratification.

Desmoplastic Trichoepithelioma With Pseudocarcinomatous Hyperplasia: A Folliculosebaceous Neoplasm in Young Persons.

ABSTRACT: Pseudocarcinomatous desmoplastic trichoepithelioma (PDTE) features verrucous squamous epidermal hyperplasia with a jagged undersurface overlying cords of follicular germinative cells in a fibrotic stroma. To date, only 5 cases have been reported. We identified 7 new PDTEs from 2 institutions and reviewed their clinical manifestations and immunohistochemical profile. The median age was 14 years (range 8-34 years). New findings included vacuolization of the basal layer of the pseudocarcinomatous surface epithelium, and the frequent presence of singly distributed sebocytes within the cords of basaloid cells. The immunohistochemical profile resembles desmoplastic trichoepithelioma, with expression of TDAG51, CK15, and Ber-Ep4. Colonizing CK20+ Merkel cells were present in all cases. PDTE needs to be differentiated from malignant neoplasms such as squamous cell carcinoma, morphoeic basal cell carcinoma, and microcystic adnexal carcinoma. Recognizing the features of this sclerosing folliculosebaceous neoplasm facilitates accurate diagnosis and avoids overtreatment.

Human gastrointestinal epithelia of the esophagus, stomach, and duodenum resolved at single-cell resolution.

The upper gastrointestinal tract, consisting of the esophagus, stomach, and duodenum, controls food transport, digestion, nutrient uptake, and hormone production. By single-cell analysis of healthy epithelia of these human organs, we molecularly define their distinct cell types. We identify a quiescent COL17A1high KRT15high stem/progenitor cell population in the most basal cell layer of the esophagus and detect substantial gene expression differences between identical cell types of the human and mouse stomach. Selective expression of BEST4, CFTR, guanylin, and uroguanylin identifies a rare duodenal cell type, referred to as BCHE cell, which likely mediates high-volume fluid secretion because of continual activation of the CFTR channel by guanylin/uroguanylin-mediated autocrine signaling. Serotonin-producing enterochromaffin cells in the antral stomach significantly differ in gene expression from duodenal enterochromaffin cells. We, furthermore, discover that the histamine-producing enterochromaffin-like cells in the oxyntic stomach express the luteinizing hormone, yet another member of the enteroendocrine hormone family.

Histopathological effect of pterostilbene as chemoprevention in N-nitroso-tri-chloroethylurea (NTCU)-induced lung squamous cell carcinoma (SCC) mouse model.

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths, and squamous cell carcinoma (SCC) is one of the most common types of lung cancer. Chemoprevention of lung cancer has gained increasing popularity as an alternative to treatment in reducing the burden of lung cancer. Pterostilbene (PS) may be developed as a chemopreventive agent due to its pharmacological activities, such as anti-proliferative, anti-inflammatory and antioxidant properties. This study aimed to investigate the effect of PS on the development of lung SCC in the mouse model. METHODS: A total of 24 seven-week-old female Balb/C mice were randomly categorised into four groups, including two control groups comprising the N-nitroso-trischloroethylurea (NTCU)-induced lung SCC and vehicle control (VC) groups and two treatment groups comprising the 10mg/kg PS (PS10) and 50mg/kg PS (PS50) groups. All lung organs were harvested at week 26 for histopathological analysis. RESULTS: All PS treatment groups showed chemopreventive activity by inhibiting the progression of lung SCC formation with PS10, resulting in mild hyperplasia, and PS50 was completely reversed in the normal bronchial epithelium layer compared with the VC group. PS treatment also reduced the expression of cytokeratin 5/6 in the bronchial epithelium layer. Both PS10 and PS50 significantly reduced the epithelium thickness compared to the NTCU group (p<0.05). PS is a potential chemopreventive agent against lung SCC growth by suppressing the progression of pre-malignant lesions and reducing the thickness of the bronchial epithelium. CONCLUSIONS: The underlying molecular mechanisms of PS in lung SCC should be further studied.

Deletion of p53 and Hyper-Activation of PIK3CA in Keratin-15+ Stem Cells Lead to the Development of Spontaneous Squamous Cell Carcinoma.

Squamous cell carcinoma (SCC) is the second commonest type of skin cancer, and SCCs make up about 90% of head and neck cancers (HNSCCs). HNSCCs harbor two frequent molecular alterations, namely, gain-of-function alterations of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and loss-of-function mutations of tumor protein p53 (TP53). However, it remains poorly understood whether HNSCCs harboring different genetic alterations exhibit differential immune tumor microenvironments (TME). It also remains unknown whether PIK3CA hyperactivation and TP53 deletion can lead to SCC development spontaneously. Here, we analyzed the Cancer Genome Atlas (TCGA) datasets of HNSCCs and found that patients with both PIK3CA and TP53 alterations exhibited worse survival, significantly lower CD8 tumor infiltrating lymphocytes (TILs) and higher M0 macrophages than other controls. To better model human tumorigenesis, we deleted TP53 and constitutively activated PIK3CA in mouse keratin-15-expressing stem cells, which leads to the spontaneous development of multilineage tumors including SCCs, termed Keratin-15-p53-PIK3CA (KPPA) tumors. KPPA tumors were heavily infiltrated with myeloid-derived suppressor cells (MDSCs), with a drastically increased ratio of polymorphonuclear-MDSC (PMN-MDSC) versus monocytic-MDSC (M-MDSC). CD8 TILs expressed more PD-1 and reduced their polyfunctionality. Overall, we established a genetic model to mimic human HNSCC pathogenesis, manifested with an immunosuppressive TME, which may help further elucidate immune evasion mechanisms and develop more effective immunotherapies for HNSCCs.

KRT 15 as a prognostic biomarker is highly expressed in esophageal carcinoma.

Aim: To investigate the expression and prognostic value of KRT 15 in esophageal carcinoma. Materials & methods: The expression levels of KRT 15 were measured in 128 cases of esophageal carcinoma and matched adjacent normal tissues by immunohistochemistry and Western blot assays. Results & conclusion: Western blot analysis shown the expression levels of KRT 15 in esophageal carcinoma were significantly higher compared with those in matched adjacent normal tissues (p < 0.001). immunohistochemistry result shown the high-expression rate of KRT 15 in esophageal carcinoma were 56.3%, which was significantly higher than those in normal tissues (35.9%; p = 0.002). KRT 15 high-expression correlated with T stage, lymph node metastasis, tumor node metastasis stage and prognosis (p < 0.05). These data indicate KRT 15 as a prognostic biomarker is highly expressed in esophageal carcinoma.