ABSTRACT
DAXX and or ATRX loss occur in 40% of pancreatic neuroendocrine tumors (PanNETs). PanNETs negative for DAXX or ATRX show an increased risk of relapse. The tumor-associated pathways activated upon DAXX or ATRX loss and how this event may induce chromosomal instability (CIN) and alternative lengthening telomeres (ALT) are still unknown. Both DAXX and ATRX are involved in DNA methylation regulation. DNA methylation of heterochromatin and of non-coding sequences is extremely important for the maintenance of genomic stability. We analyzed the association of DAXX and/or ATRX loss and CIN with global DNA methylation in human PanNET samples and the effect of DAXX knock-down on methylation and cell proliferation. We assessed LINE1 as well as global DNA methylation in 167 PanNETs, and we found that DAXX and or ATRX-negative tumors and tumors with CIN were hypomethylated. DAXX knock-down in PanNET cell lines blocked cells in G1/G0 phase and seemed to increase CIN in QGP-1 cells. However, no direct changes in DNA methylation were observed after DAXX knock-down in vitro In conclusion, our data indicate that epigenetic changes are crucial steps in the progression of PanNETs loss and suggest that DNA methylation is the mechanism via which CIN is induced, allowing clonal expansion and selection.
Subject(s)
Chromosomal Instability/genetics , DNA Methylation , Neuroendocrine Tumors/genetics , Pancreatic Neoplasms/genetics , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Cell Line, Tumor , Cell Survival , Co-Repressor Proteins , Female , Humans , Male , Middle Aged , Molecular Chaperones , Neuroendocrine Tumors/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Pancreatic Neoplasms/metabolism , X-linked Nuclear Protein/genetics , X-linked Nuclear Protein/metabolismABSTRACT
AIMS: The aim of this study is to evaluate the pathological features, serum hormone levels and ex vivo cultures of pituitary adenomas that occur in rats affected by MENX syndrome. MENX is multiple endocrine neoplasia syndrome caused by a germline mutation in the cell cycle inhibitor p27. Characterization of MENX adenomas is a prerequisite to exploit this animal model for molecular and translational studies of pituitary adenomas. METHODS: We investigated MENX pituitary adenomas with immunohistochemistry, double immunofluorescence, electron microscopy, reverse transcription polymerase chain reaction (RT-PCR), measurement of serum hormone levels and ex vivo cultures. RESULTS: Adenomas in MENX rats belong to the gonadotroph lineage. They start from 4 months of age as multiple neoplastic nodules and progress to become large lesions that efface the gland. Adenomas are composed of chromophobic cells predominantly expressing the glycoprotein alpha-subunit (αGSU). They show mitotic activity and high Ki67 labelling. A few neoplastic cells co-express gonadotropins and the transcription factor steroidogenic factor 1, together with growth hormone or prolactin and Pit-1, suggesting that they are not fully committed to one cell lineage. Ex vivo cultures show features similar to the primary tumour. CONCLUSIONS: Our results suggest that p27 function is critical to regulate gonadotroph cells growth. The MENX syndrome represents a unique model to elucidate the physiological and molecular mechanisms mediating the pathogenesis of gonadotroph adenomas.
Subject(s)
Adenoma/pathology , Cyclin-Dependent Kinase Inhibitor p27/genetics , Multiple Endocrine Neoplasia/pathology , Pituitary Neoplasms/pathology , Adenoma/genetics , Adenoma/metabolism , Animals , Cyclin-Dependent Kinase Inhibitor p27/metabolism , Disease Models, Animal , Fluorescent Antibody Technique , Gonadotropins/genetics , Immunohistochemistry , Multiple Endocrine Neoplasia/genetics , Multiple Endocrine Neoplasia/metabolism , Pituitary Neoplasms/genetics , Pituitary Neoplasms/metabolism , Rats , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
A study was performed on the B lymphocyte membrane markers in patients with osteosarcoma. The findings obtained would indicated apparently normal cell function conditions (intracytoplasmic membrane immunofluorescence, PWM lymphocyte blastogenesis) and a marked cytotoxic lymphocyte drop ("killer" lymphocytes: EA rosettes).
Subject(s)
B-Lymphocytes/immunology , Bone Neoplasms/immunology , Osteosarcoma/immunology , Antibody Formation , Antigens, Neoplasm/isolation & purification , Cell Membrane/immunology , Fluorescent Antibody Technique , Humans , Immune Adherence Reaction , Lymphocyte ActivationABSTRACT
Some parameters of the T-lymphocyte dependent system have been studied in 20 patients with osteosarcoma. The functional condition of T lymphocytes, stimulated with mitogens (PHA and Con-A) has been investigated by evaluating DNA neosynthesis by means of the incorporation of the tritiated thymidine in lymphocyte cultures. The percentage of rosette-forming T l-mphocytes with sheep erythrocytes has been assessed. The findings would indicate a constant inhibition of DNA biosynthesis in patients with osteosarcoma, only in correspondence of PHA stimulation. This finding would agree with E rosette pattern. In this case also neoplastic patients do show, in comparison with the controls, a constant drop of the number of T lymphocytes forming rosettes with sheep erythrocytes.
Subject(s)
Bone Neoplasms/immunology , Osteosarcoma/immunology , T-Lymphocytes/immunology , Animals , Antibody Formation , Humans , Immune Adherence Reaction , Lymphocyte Activation , SheepABSTRACT
The acetylsalicylic acid, like other drugs with analogous properties, is an anti-inflammatory drug, whose mechanism of action is still unknown. Lymphocyte release, on stimulation, phlogogenic substances (lymphokines) which are responsible for some phlogistic processes, above all chronic. Acetylsalicylic acid inhibits some lymphocyte functions, therfore its mechanism of action may be possibly accounted for by this activity. This paper dealt with the effect observed that acetylsalicylic acid on mitogen-induced lymphocyte blastization. In vitro it was observed that acetylsalicylic acid inhibits blastization only when it is present in the incubation medium and that the inhibitor effect is dose dependent. In vivo, in the rat, it was observed that acetylsalicylic acid inhibits blastization only when administered some hours before lymphocyte withdrawal. The Authors believe that this effect may be accounted for by a metabolite of the drug itself.
Subject(s)
Aspirin/pharmacology , Lymphocyte Activation/drug effects , Animals , Antibody Formation/drug effects , Dose-Response Relationship, Drug , Lymphocytes/immunology , Mitogens/pharmacology , RatsABSTRACT
The sensitization of the patients submitted to arthroplasty has been pointed out with increasing frequency. This paper attempted to establish the occurrence rate and the importance of this sensitization in patients submitted to arthroplasty of metallic or plastic type, by means of the patch-test, blastization and macrophage inhibition test. The highest positivity incidence was observed towards chromium (9.7%) and cobalt (6.4%) in the patients submitted to arthroplasty of metallic type, while that of plastic type showed a 1% positivity to methylacrylate. These data stress the importance of the adoption of the patch-test in all patients, before being submitted to any type of prosthesis, and of the preferential use of those prostheses which turned out less sensitizing.
Subject(s)
Arthroplasty/adverse effects , Joint Prosthesis/adverse effects , Metals/adverse effects , Chromium/adverse effects , Cobalt/adverse effects , Dermatitis, Contact/etiology , Humans , Methacrylates/adverse effects , Nickel/adverse effectsABSTRACT
Some technical details are given with regard to making up the E.D.F. corrective corset used by the authors, who have wide experience in the bloodless treatment of infantile and youthful evolutive scoliosis, with a view to a wider spread of prophylaxis and treatment appliances by the Higher Health Boards today in operation.