Redistribution of β-catenin in response to EGF and lithium signalling in human oesophageal squamous carcinoma cell lines

Role of Cell-Cell Junctions in Oesophageal Squamous Cell Carcinoma

Cell-cell junctions comprise various structures, including adherens junctions, tight junctions, desmosomes, and gap junctions. They link cells to each other in tissues and regulate tissue homeostasis in critical cellular processes. Recent advances in cell-cell junction research have led to critical discoveries. Cell-cell adhesion components are important for the invasion and metastasis of tumour cells, which are not only related to cell-cell adhesion changes, but they are also involved in critical molecular signal pathways. They are of great significance, especially given that relevant molecular mechanisms are being discovered, there are an increasing number of emerging biomarkers, targeted therapies are becoming a future therapeutic concern, and there is an increased number of therapeutic agents undergoing clinical trials. Oesophageal squamous cell carcinoma (ESCC), the most common histological subtype of oesophageal cancer, is one of the most common cancers to affect epithelial tissue. ESCC progression is accompanied by the abnormal expression or localisation of components at cell-cell junctions. This review will discuss the recent scientific developments related to the molecules at cell-cell junctions and their role in ESCC to offer valuable insights for readers, provide a global view of the relationships between position, construction, and function, and give a reference for future mechanistic studies, diagnoses, and therapeutic developments.

Clinical significance of expression of Klotho and β-Catenin in esophageal squamous cell carcinoma

AIM: To investigate the clinical significance of expression of Klotho and β-Catenin in esophageal carcinoma.

METHODS: Tissue microarray technique and immunohistochemistry were used to examine Klotho and β-Catenin expression in 75 esophageal carcinoma tissue specimens and matched tumor-adjacent esophageal tissue. Correlations between Klotho and β-Catenin expression and clinical and pathological features were then analyzed.

RESULTS: The positive rate of Klotho expression was significantly lower in esophageal carcinoma tissue than in tumor-adjacent tissue (14.9% vs 63.4%, P < 0.05). The expression of Klotho was correlated with tumor invasion and clinical stage (both P < 0.05). The positive rate of β-Catenin expression was significantly higher in esophageal carcinoma tissue than in tumor-adjacent tissue (80.0% vs 16.4%, P < 0.05). The expression of Klotho was correlated with lymph node metastasis and tumor clinical stage (r = -0.276, P < 0.05).

CONCLUSION: The positive rates of Klotho and β-Catenin expression differed significantly between esophageal carcinoma and tumor-adjacent tissue. Klotho and β-Catenin may be used as important markers for esophageal carcinoma and are helpful for prognosis prediction in esophageal carcinoma.

BMP-2-Modulated Chondrogenic Differentiation In Vitro Involves Down-Regulation of Membrane-Bound Beta-Catenin

Bone morphogenetic proteins (BMPs) are important regulators of cellular differentiation and embryonic development. Beta catenin mediated nuclear signaling has been implicated in BMP-2-modulated chondrogenic differentiation in the pluripotential stem cell line C3H10T1/2. However, there is little information on the functional role of beta catenin in BMP-2-modulated differentiation of primary nontransformed mesenchymal cells. Here, we present evidence to show that BMP-2-induced chondrogenic differentiation in high-density primary mesenchymal culture is associated with a significant decrease in membrane-bound beta catenin by 72 hours compared to controls. Nuclear localization of beta catenin is not detectable by immunofluorescence and the TCF-responsive reporter vector TOPFLASH shows only background activity during chondrogenic differentiation. BMP-2-treated cultures show reduced cell-cell adhesion by 72 hours, which correlates with the changes in levels of membrane-bound beta catenin. Up-regulation of membrane-bound beta catenin blocks the effect of BMP-2 on both chondrogenic differentiation and cell-cell adhesiveness. These findings suggest that BMP-2 can modulate the adhesivity of adherens junctions through regulation of membrane bound beta catenin.

Photolon™, a chlorin e6 derivative, triggers ROS production and light-dependent cell death via necrosis

Photolon is a photosensitiser with demonstrated potential as an anti-tumour agent. In this study, an in vitro investigation was performed to determine the mechanism of Photolon-induced cell death. Cell killing was observed in a light-dependent manner and light-activated Photolon resulted in a significant production of reactive oxygen species (ROS), which could be blocked by type I ROS scavengers. Inhibition of ROS production using Trolox prevented Photolon-induced cell death. Light-activated Photolon caused no increase in caspase-3/7 activity, but a rapid increase in lactate dehydrogenase (LDH) release suggesting a loss of membrane integrity and subsequent cell death by necrosis. We conclude that the mechanism of Photolon-induced cell death involves the induction of ROS via a type I mechanism, which is ultimately responsible for cell killing by necrosis.