Expression of blood group H antigen type 2 chain by oral carcinoma cells after radiotherapy

The H2B ubiquitin-protein ligase RNF40 is required for somatic cell reprogramming

Direct reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) requires a resetting of the epigenome in order to facilitate a cell fate transition. Previous studies have shown that epigenetic modifying enzymes play a central role in controlling induced pluripotency and the generation of iPSC. Here we show that RNF40, a histone H2B lysine 120 E3 ubiquitin-protein ligase, is specifically required for early reprogramming during induced pluripotency. Loss of RNF40-mediated H2B monoubiquitination (H2Bub1) impaired early gene activation in reprogramming. We further show that RNF40 contributes to tissue-specific gene suppression via indirect effects by controlling the expression of the polycomb repressive complex-2 histone methyltransferase component EZH2, as well as through more direct effects by promoting the resolution of H3K4me3/H3K27me3 bivalency on H2Bub1-occupied pluripotency genes. Thus, we identify RNF40 as a central epigenetic mediator of cell state transition with distinct functions in resetting somatic cell state to pluripotency.

Expression of mucin type carbohydrates may supplement histologic diagnosis in oral premalignant lesions

Recent studies have shown that changes within membrane bound carbohydrates may be essential for cellular differentiation and malignant transformation. We have therefore, by means of immunohistochemistry, studied the expression of T/Tn related (Thomsen-Friedenrich) carbohydrates in 13 oral lesions with squamous cell dysplasia. The epithelial grade of dysplasia was graded as mild, moderate or severe. The following carbohydrate structures were studied: Tn, T, mucintype 3 chain H, and the sialylated derivates, sialosyl-Tn and sialosyl-T. In general, short structures were detected on the basal cells and longer structures on the more mature spinous cells. In many cases, this sequential expression was more disturbed with increasing grade of epithelial dysplasia. However, our results also showed that some lesions with the same grade of epithelial dysplasia showed different carbohydrate expression. These findings indicate that expression of carbohydrates may supplement histologic diagnosis in the evaluation of the prognosis of premalignant lesions.

Loss of expression of blood group antigen H is associated with cellular invasion and spread of oral squamous cell carcinomas

Membrane-bound carbohydrates may influence the metastatic behavior of cancer cells. Forty-two squamous cell carcinomas (SCC) of the buccal and maxillary alveolar mucosa were studied retrospectively using a monoclonal antibody (BE2) that reacts with blood group H (type 2 chain) structure. H-antigen staining within the entire tumor did not correlate with the stage of the tumor, i.e., spread of the tumors. However, loss of staining within the most invasive sites of the tumors correlated significantly with the stage of tumor development and histologic grade of malignancy. These findings support the view that features relating to the cells of deeper parts of the carcinomas are very important for the clinical behavior of the tumors, and that loss of H-antigen expression is related to the stage of tumor and invasion of carcinoma cells.

Loss of expression of blood group antigen H is associated with cellular invasion and spread of oral squamous cell carcinomas

Membrane-bound carbohydrates may influence the metastatic behavior of cancer cells. Forty-two squamous cell carcinomas (SCC) of the buccal and maxillary alveolar mucosa were studied retrospectively using a monoclonal antibody (BE2) that reacts with blood group H (type 2 chain) structure and an immunoperoxidase (avidin-biotin peroxidase complex) staining technique. H-antigen staining within the entire tumor did not correlate with the stage of the tumor, i.e., tumor spread. However, loss of staining within the most invasive sites of the tumors correlated significantly with the stage of tumor development and histologic grade of malignancy. These findings support the view that features regarding the cells of deeper parts of the carcinomas are very important for the clinical behavior of the tumors and that loss of H-antigen expression is related to the stage of the tumor and invasion of carcinoma cells.

Differential lectin-bindings in normal and precancerous epithelium and squamous cell carcinoma of the oral mucosa

In order to establish a useful and objective marker of malignancy of oral mucosa, the binding sites for Ulex europaeus agglutinin I (UEA-I). Bandeiraea simplicifolia agglutinin I (BSA-I) and peanut agglutinin (PNA) were comparatively examined in the surgical materials from the normal, dysplastic and cancerous epithelium of the oral mucosa by a novel lectin-antilectin immunoperoxidase method. Based on the staining patterns of the normal keratinized epithelium, UEA-I was regarded as the marker for the prickle cells, BSA-I for the cells in the upper prickle to the horny layers, and PNA for those in the basal layer. As the degree of dysplasia advanced, all layers of epithelium came to react with UEA-I and PNA, whereas the BSA-I binding was negative. Positive reactions for UEA-I and PNA were seen in most carcinoma cells other than the keratinizing foci stained by BSA-I. The results indicate that a UEA-I-positive reaction in the basal cells, a PNA-positive in the prickle cells and loss of receptor for BSA-I occur in the course of malignant transformation of oral mucosa, and that these lectins may be regarded as useful markers of oral epithelial cytoplasmic differentiation.