Identification of stemness-related glycosylation changes in head and neck squamous cell carcinoma.

BACKGROUND: Altered glycosylation is a hallmark of cancer associated with therapy resistance and tumor behavior. In this study, we investigated the glycosylation profile of stemness-related proteins OCT4, CIP2A, MET, and LIMA1 in HNSCC tumors. METHODS: Tumor, adjacent normal tissue, and blood samples of 25 patients were collected together with clinical details. After tissue processing, lectin-based glycovariant screens were performed. RESULTS: Strong correlation between glycosylation profiles of all four stemness-related proteins was observed in tumor tissue, whereas glycosylation in tumor tissue, adjacent normal tissue, and serum was differential. CONCLUSIONS: A mannose- and galactose-rich glycosylation niche associated with stemness-related proteins was identified.

Expression of green fluorescent protein under beta-actin promoter in living spermatogenic cells of the mouse: stage-specific regulation by FSH.

Spermatogenic cells from a mouse strain expressing enhanced green fluorescent protein (EGFP) under chicken beta-actin promoter were studied under living conditions to analyse stage- and cell-specific expression and hormonal regulation of the transgene. The isolated seminiferous tubules were examined by transillumination and the live cell squashes by phase contrast and fluorescence microscopy. FSH effects were measured in whole seminiferous tubules comparing stages I-VI, VII-VIII and IX-XII of the cycle. Beta-actin was highly expressed in spermatogonia, but almost no expression was found at early meiosis (leptotene spermatocytes). A gradual increase in translation of beta-actin was found during later stages of meiosis and early spermiogenesis, with a maximum in elongating spermatids. FSH increased the translation of beta-actin after 4 h and 24 h of incubation at stages I-VI, after 24 h at stages VII-VIII but not at stages IX-XII of the cycle. The results support the view that beta-actin plays a role in the nuclear elongation of spermatids and that its expression is regulated by FSH in a stage-specific fashion. Techniques used in this study give us new insight to study temporal and hormonal regulation of gene products in living spermatogenic cells.

Regulation of acrosome formation in mice expressing green fluorescent protein as a marker.

Transgenic mice expressing enhanced green fluorescent protein under acrosin promoter were used to study the role of the Golgi complex and of the cytoskeleton during early development of the acrosomic system in exactly defined stages of the seminiferous epithelial cycle during in vitro differentiation. First acrosin expression was found uniformly in the cytoplasm of stage IV pachytene spermatocytes. The steady-state level increased up to stage X pachytene spermatocytes, and in diakinetic primary spermatocytes, acrosin started to accumulate into the Golgi complex. During step 2 of spermiogenesis, several small fluorescent proacrosomic granules were seen in various parts of the Golgi complex, and they fused to a solid acrosomic system at step 3. In cultured stage I-III seminiferous tubule segments, nocodazole slowed down acrosin incorporation and increased the distance of the acrosomic system from the nucleus. Follicle stimulating hormone had an opposite effect by increasing density of the acrosomic system together with activation of the surrounding microtubule network. The observations suggest that microtubules have an important function during the early differentiation of the acrosomic system.