FSH modulatory effect on human granulosa cells: a gene-protein candidate for gonadotrophin surge-attenuating factor.

Previous evidence indicates a homology of gonadotrophin surge-attenuating factor (GnSAF) to the carboxyl terminal of human serum albumin (HSA) and the ability of human granulosa cells to produce mRNA transcripts corresponding to this fragment, but the underlying mechanism is still unknown. This study investigated the role of FSH in vitro in the expression of the carboxyl terminal of HSA by human luteinized granulosa cells. Cells were cultured on poly-l-lysine-coated microscope slides in the absence or presence of 10 ng/ml FSH, followed by in-situ hybridization and immunocytochemistry. In the presence of FSH, mRNA transcripts corresponding to the carboxyl terminal of the HSA gene and corresponding protein could be detected in comparable intensity to that seen by hepatic HepG2 cells (positive control). Significantly lower expression was detected in granulosa cells cultured without FSH addition (P<0.01), but no expression was detected in HeLa cells. These results demonstrate for the first time that FSH stimulates the expression of the carboxyl terminal fragment of the HSA gene and corresponding protein in human luteinized granulosa cells. Therefore, the carboxyl terminal of HSA has a functional role in the ovary and this further supports the notion that this HSA fragment is a GnSAF-bioactive entity.

Aberrant methylation of c-myc and c-fos protooncogenes and p53 tumor suppressor gene in myelodysplastic syndromes and acute non-lymphocytic leukemia.

PURPOSE: Aberrant methylation, as an epigenetic phenomenon, may precede and regulate the expression of genes involved in transformation mechanisms that lead to leukemogenesis of hemopoietic cells. The genes involved mostly encode transcription factors and cell cycle specific inhibitors. The aim of this project was to study the DNA methylation pattern of c-myc, c-fos and p53 in myelodysplastic syndromes (MDS) and in acute non-lymphocytic leukemias (ANLL). PATIENTS AND METHODS: DNA was isolated from the monocyte cell layer harvested from bone marrow or peripheral blood samples of 44 patients suffering from MDS and ANLL. Genomic DNA was digested with methylation-specific enzymes, and was electrophoresed and hybridized with probes specific for human c-myc, c-fos and p53 genes. RESULTS: In MDS, the c-myc gene in exons 2 and 3 was regionally hypomethylated, whereas exon 2 in ANLL was hypermethylated and exon 3 hypomethylated. The c-fos gene was hypomethylated in ANLL type 4 and presented aberrant hypomethylation in the different types of MDS. The p53 anti-oncogene appeared extensively hypomethylated in MDS. CONCLUSION: Aberrant DNA methylation pattern of the c-myc, c-fos and p53 tumor suppressor gene seems to be a primary event in the transformation process from myelodysplasia to acute leukemia, affecting their expression, and, consequently, altering the proliferation, differentiation or apoptosis of hemopoietic precursor cells. The p53 hypomethylation predisposes to critical mutations that enhance the transformation process of myelodysplasia to leukemia. The recognition of altered methylation of these genes in myelodysplasia may have prognostic implications and may lead to novel therapeutic modalities.