The expression of keratin 6 is regulated by the activation of the ERK1/2 pathway in arsenite transformed human urothelial cells

CEP55 3'-UTR promotes epithelial-mesenchymal transition and enhances tumorigenicity of bladder cancer cells by acting as a ceRNA regulating miR-497-5p

BACKGROUND

Centrosomal protein 55 (CEP55) is implicated in the tumorigenesis of bladder cancer (BC) but the detailed molecular mechanisms are unknown. We aim to develop a potential competing endogenous RNA (ceRNA) network related with CEP55 in BC.

METHODS

We first extracted the expression profiles of RNAs from The Cancer Genome Atlas (TCGA) database and used bioinformatic analysis to establish ceRNAs in BC. Real-time quantity PCR (RT-qPCR) and immunohistochemical analysis were performed to measure CEP55 expression in different bladder cell lines and different grades of cancer. Bioinformatics analysis and luciferase assays were conducted to predict potential binding sites among miR-497-5p, CEP55, parathyroid hormone like hormone (PTHLH) and high mobility group A2 (HMGA2). Tumor xenograft model was used to show the effect of CEP55 3'-UTR on cisplatin therapy. Bioinformatics analysis, luciferase assays, and 5' rapid amplification of cDNA ends (5'RACE) were to explore the function of CEP55 3'-untranslated region (3'-UTR) on targeting miR-497-5p. Western blot and immunofluorescence assays were to detect the epithelial-mesenchymal transition (EMT) induction of CEP55 3'-UTR.

RESULTS

CEP55 expression as well as the expression levels of the oncogenic proteins PTHLH and HMGA2 were upregulated in BC cells while miR-497-5p was downregulated. Low miR-497-5p expression and high CEP55 and HMGA2 expression levels were associated with more advanced tumor clinical stage and pathological grade. Overexpression of the CEP55 3'-UTR promoted the proliferation, migration, and invasion of the EJ cell line in vitro and accelerated EJ-derived tumor growth in nude mice, while inhibition of the CEP55 3'-UTR suppressed all of these oncogenic processes. In addition, CEP55 3'-UTR upregulation reduced the cisplatin sensitivity of BC cell lines and xenograft tumors. Bioinformatics analysis, luciferase assays, and 5'RACE suggested that the CEP55 3'-UTR functions as a ceRNA targeting miR-497-5p, leading to miR-497-5p downregulation and disinhibition of PTHLH and HMGA2 expression. Further, CEP55 downregulated miR-497-5p transcription by promoting NF-[Formula: see text]B signaling. In turn, CEP55 3'-UTR ultimately promotes EMT and tumorigenesis by activating P38MAPK and ERK 1/2 pathways.

CONCLUSIONS

These results suggest that a ceRNA regulatory network involving CEP55 upregulates PTHLH and HMGA2 expression by suppressing endogenous miR-497-5p. We unveiled a novel mechanism of BC metastasis, and could become novel therapeutics targets in BC.

Identification of Critical Pathways and Potential Key Genes in Poorly Differentiated Pancreatic Adenocarcinoma

Introduction

The poorly differentiated pancreatic adenocarcinoma (PDAC) is an extremely lethal neoplasm without effective biomarkers for early detection and prognosis prediction, which is characteristically unresponsive to chemotherapeutic regimens. This study aims at searching for key genes which could be applied as novel prognostic biomarkers and therapeutic targets in PDAC.

Methods

Clinical samples were collected and a comprehensive differential analysis of seven PDAC samples by integrating RNA-seq data of tumor tissues and matched normal tissues from both our cohort and gene expression profiling interactive analysis (GEPIA) were performed to discover potential prognostic genes in PDAC. Pathway enrichment analysis was carried out to determine the biological function of PDAC differentially expressed genes (DEGs), and protein-protein interaction (PPI) network was constructed for functional modules analysis. Real-time PCR was performed to validate expression of hub genes.

Results

A total of 126 PDAC-specific expressed genes identified from seven PDAC samples were predominantly enriched in cell adhesion, integral component of membrane, signal transduction and chemical carcinogenesis, IL-17 signaling pathway, indicating that obtained genes might play a unique role in PDAC tumorigenesis. Furthermore, survival analysis revealed that five genes (CEACAM5, KRT6A, KRT6B, KRT7, KRT17) which exhibited high expression levels in tumor tissues were obviously correlated with the prognosis of PDAC patients and KRT7 was positively correlated with KRT6A, KRT6B, KRT17 expression. In addition, real-time PCR demonstrated that the expression level of the hub genes was consistent with RNA-seq analysis.

Discussion

The current study suggested that CEACAM5, KRT6A, KRT6B, KRT7, and KRT17 may represent novel prognostic biomarkers as well as novel therapeutic targets for poorly differentiated PDAC.

Sunitinib decreases the expression of KRT6A and SERPINB1 in 3D human epidermal models

Hand-foot skin reaction (HFSR) is a common side effect caused by several tyrosine kinase inhibitors, including sunitinib. However, the nature of the cornifying factors related to the molecular biological mechanisms underlying HFSR remains poorly understood. We used human keratinocyte models to investigate the key cornifying factors for dermatological and biological abnormalities induced by sunitinib. On the basis of the results of microarray analysis using the three-dimensional (3D) human epidermal model, keratin (KRT)6A, serine protease inhibitor (SERPIN)B1, KRT5, and SERPIN Kazal-type 6 were selected as candidate genes related to HFSR. Sunitinib treatment significantly decreased the expression of SERPINB1 and KRT6A in the immunohistochemical staining of the 3D epidermal model. In PSVK1 cells, but not in normal human epidermal keratinocyte cells, both of which are human normal keratinocyte cell lines, sunitinib decreased the expression of KRT6A with a concomitant decrease in levels of phosphorylated extracellular signal-regulated kinases (ERK)1/2 and phosphorylated p38 mitogen-activated protein kinase (MAPK). Inhibitors of the ERK and p38 MAPK signal pathways also significantly decreased KRT6A expression. Sunitinib-induced decrease in KRT6A expression was suppressed by the inhibition of glycogen synthase kinase-3β by enhancing ERK1/2 and p38 MAPK phosphorylation. Thus, sunitinib reduces the expression of KRT6A and SERPINB1 by inhibiting the ERK1/2 and p38 MAPK signalling pathways in the skin model. These changes in expression contribute to the pathology of HFSR.

Colon cancer combined with obesity indicates improved survival- research on relevant mechanism

Obesity contributes to the incidence of various tumors, including colon cancer. However, the impact of obesity on patients’ survival and related mechanisms remains unclear. Multi-omics data of 227 cases of colon cancer patients combined with clinical characteristics data were acquired from The Cancer Genome Atlas (TCGA) database. We confirmed obesity as an independent prognostic factor for improved overall survival of colon cancer patients. We demonstrated that hypoxia pathways were repressed in obese patients by regulating miR-210. Immune checkpoints PD-1 and LAG3 were also downregulated in obese patients, which indicated enhanced immune surveillance. The frequency of PIK3CA and KRAS mutations was decreased in obese patients. The sites and types of TP53 mutation were alternated in obesity patients. In conclusion, our research demonstrated the potential mechanisms of prolonged survival in colon cancer patients combined with obesity, which may provide potential value for improving the prognosis of colon cancer.

High expression of keratin 6C is associated with poor prognosis and accelerates cancer proliferation and migration by modulating epithelial-mesenchymal transition in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is a more frequent subtype of lung cancer and most cases are discovered in the late stages. The proliferation and metastasis of LUAD are pivotal for disease progression. Despite unremitting deeper understanding of LUAD biology, the mechanisms involved in the proliferation and metastasis of LUAD remain unclear. The objective of our article was to inquiry the expression and the function of keratin 6C (KRT6C) in LUAD cells.

METHODS

First, the expression level and prognostic value of KRT6C in LUAD tissues were analyzed on the basis of the data acquired from TCGA database. Through qRT-PCR, the expression level of KRT6C on LUAD cell lines (A549, H1299, PC-9) and human normal lung cell line MRC-5 was tested. After that, CCK8 and colony formation assays was utilized to detect cell proliferation. In addition, to explore the influence of KRT6C on LUAD migration and invasion ability, scratch wound healing and transwell assays were utilized. Through western blotting, the protein expression levels of KRT6C, PCNA, E-cadherin, N-cadherin, Snail and Vimentin were detected.

RESULTS

The outcomes revealed that KRT6C was highly expressed in LUAD tissues and cell lines. Besides, elevated level of KRT6C was related to worse prognosis in LUAD patients. Ablation of KRT6C restrained proliferation, migration and invasion of A549 cells. KRT6C deficiency augmented the expression of E-cadherin as well as reduced the expression of N-cadherin, Snail and Vimentin.

CONCLUSION

Above all, these consequences indicated that depletion of KRT6C suppressed A549 cell proliferation, migration and invasion, which might be achieved by regulating EMT. In general, KRT6C is identified as a potential therapeutic target for LUAD.

The urothelial cell line UROtsa transformed by arsenite and cadmium display basal characteristics associated with muscle invasive urothelial cancers

Muscle invasive urothelial carcinomas are divided into various molecular subtypes with basal and luminal subtypes being the prominent ones. The basal muscle-invasive urothelial carcinomas are generally more aggressive at presentation and significantly enriched with squamous features. Our laboratory has developed an in-vitro model of urothelial cancer by transforming the immortalized cell line UROtsa with arsenite (As³⁺) and cadmium (Cd²⁺). In this study, we characterized the tumors formed by these transformed cell lines as more basal-like based on their gene expression patterns with increased expression of KRT1, KRT5, KRT6, KRT14, KRT16, KRT17 and CD44. In addition, histological examination of these tumor transplants showed squamous features enriched in basal muscle invasive urothelial carcinomas. The expression of these genes increased in the transformed cell lines as well as in the urospheres, which are putative cancer initiating cells/stem cells derived from the cell lines. There was also increased expression of these genes in the urospheres derived from the parent UROtsa cell line. Thus, our data shows that the As³⁺ and Cd²⁺-transformed cell lines and their derived tumor transplants have gene expression profiles similar to the basal subtype of muscle invasive bladder carcinomas with tumors having enriched squamous features. The increased expression of basal markers in the urospheres suggests that stem cells may be involved in the development of squamous differentiation seen in some of the muscle invasive bladder carcinomas.

Epidermal growth factor receptor function in the human urothelium

PURPOSE

Epidermal growth factor receptor (EGFr)-targeted therapy may be used in subgroups of patients with urinary bladder cancer. Here we assessed the role of EGFr in urothelial proliferation and migration in a two- and three-dimensional cell culture system.

METHODS

UROtsa cells derived from normal urothelium and malignant T24 cells were cultured in a Type I collagen gel. Proliferation and migration of urothelial cells, in the absence and presence of the EGFr inhibitor cetuximab, were assessed with a proliferation test (ATCC) and with the Axioplan 2 imaging microscope with a motorized stage (Carl Zeiss), respectively. The expressions of cytokeratin (CK) 17, CK20, EGFr, pEGFr, laminin, occludin and zonula occludens 1 (ZO-1) were assessed with immunohistochemistry and/or western blot.

RESULTS

UROtsa spheroids were formed after 7 days in culture, while T24 cells did not form spheroids. UROtsa expressed CK20 but not laminin or CK17 and consequently resembled umbrella cells. In UROtsa and T24, cetuximab inhibited urothelial proliferation, induced cleavage of EGFr and/or pEGFR but did not affect urothelial migration. The tight junction protein occludin was cleaved, and the formation of cellular spheroids was inhibited in UROtsa by the presence of cetuximab.

CONCLUSIONS

EGFr modulates urothelial proliferation and the formation of the three-dimensional structure of the urothelium possibly by interfering with occludin. The present data also show a cell culture technique enabling phenotypically normal urothelial cells to form epithelial structures in contrast to malignant urothelial cells.

HER2 and Src co-regulate proliferation, migration and transformation by downstream signaling pathways in arsenite-treated human uroepithelial cells

HER2 mediate proliferation, migration and transformation by multiple downstream signaling pathways in arsenite-treated human uroepithelial cells.

The tumor suppressor phosphatase and tensin homolog protein (PTEN) is negatively regulated by NF-κb p50 homodimers and involves histone 3 methylation/deacetylation in UROtsa cells chronically exposed to monomethylarsonous acid

UROtsa cells have been accepted as a model to study carcinogenicity mechanisms of arsenic-associated human bladder cancer. In vitro continuous exposure to monomethylarsonous acid (MMA^III), leads UROtsa cells to commit to malignant transformation. In this process, NF-κβ-associated inflammatory response seems to play an important role since this transcription factor activates some minutes after cells are exposed in vitro to MMA^III and keeps activated during the cellular malignant transformation. It is known that a slight decrease in the protein phosphatase and tensin homologue (PTEN) gene expression is enough for some cells to become malignantly transformed. Interestingly, this tumor suppressor has been proven to be negatively regulated by NF-κβ through binding to its gene promoter. Based on these observations we propose that NF-κβ may be involved in arsenic associated carcinogenesis through the negative regulation of PTEN gene expression. Changes in PTEN expression and the binding of p50 NF-κβ subunit to PTEN promoter were evaluated in UROtsa cells exposed for 4, 12, 20, or 24 wk to 50nM MMA^III. Results showed that MMA^III induced a significant decrease in PTEN expression around 20 wk exposure to MMA^III,which correlated with increased binding of p50 subunit to the PTEN promoter. Consistent with these results, ChIP assays also showed a significant decrease in H3 acetylation (H3ac) but an increase in the repression marks H3k9me3 and H327me3 in PTEN promoter when compared with not treated cells. These results suggest that the activation of NF-κβ by MMA^III may participate in UROtsa cells malignant transformation through the negative regulation of PTEN expression involving p50 homodimers-mediated chromatin remodeling around the PTEN promoter.