ECE2013 Poster Presentations Endocrine tumours and neoplasia (66 abstracts)
1Molecular Biology Laboratory, IRCCS Policlinico san Donato, San Donato Milanese (MI), Italy; 2Department of Obstetrics and Gynecology, DMSD San Paolo, University of Milan, Milan, Italy; 3Medical Genetics, IRCCS Hospital Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy; 4Endocrine Unit, IRCCS Hospital Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy; 5Endocrine Unit, Department of Biomedical Sciences for Health, University of Milan, IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy; 6Endocrine Surgery, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico-Milano, Milan, Italy; 7Surgery 1, IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy; 8Endocrine Unit, Department of Clinical Sciences and Community, University of Milan, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy; 9Human Pathology, DMSD San Paolo, San Paolo Hospital Medical School, University of Milan, Milan, Italy.
Tumour-associated fibroblasts (TAFs) are important players in tumour formation, growth, enhancement and metastasis. We firstly investigated the TAFs component in human parathyroid neoplasia from patients with primary hyperparathyroidism. Alpha-smooth muscle actin (alpha-SMA) has been used to identify activated TAFs (myofibroblasts). Culturing explants from parathyroid adenomas (PA, n=5), large spindle-shaped alpha-SMA+ cells outgrew from explants and the expression of activated fibroblasts markers such as vimentin, stromal derived factor-1 (SDF-1/CXCL12) and fibroblast activated protein were detected. Immunohistochemistry showed alpha-SMA+ cells highly represented in normal parathyroid glands (n=3) where they lined the acinar structures. In typical PAs (n=5) alpha-SMA+ cells were variably reduced, though they surrounded new microvessels suggesting a role in neoangiogenesis. Interestingly, in human fetal parathyroids (1924 weeks of gestation), myofibroblasts were exclusively found lining blood vessels. In atypical adenomas (n=3) and carcinomas (n=3), the chief cells proliferating in sheets were not sustained by myofibroblasts, which were highly represented in the fibrous bands and capsula stroma, suggesting a role of alpha-SMA+ cells in invasiveness. Coculture of human bone-marrow mesenchymal stem cells (hBM-MSCs) with PA-derived explants (n=3) induced significant increases of VEGFa mRNA expression levels in hBM-MSCs. Immunofluorescence (IF) and FACS (n=5) identified 3263% of PA-derived cells expressing CXCR4, the SDF-1 receptor, whose 4790% coexpressing PTH and CXCR4. Treatment of cocultures with the CXCR4 antagonist AMD3100 reduced the coculture-stimulated VEGFa mRNA expression in hBM-MSCs, suggesting that the proangiogenic effect might be regulated through the CXCR4/SDF-1 pathway. A subset of alpha-SMA+ cells were shown by IF to co-express the haematopoietic marker CD34 suggesting they might be perivascular adipose-tissue derived mesenchymal progenitors. A subset of alpha-SMA+ cells also co-expressed the parathyroid marker GCM2, and the endodermic transcription factor TBX1, suggesting they might derived from chief cells through epithelial-to-mesenchymal transition. In conclusions, we identified in parathyroid neoplasia cells showing features of activated TAFs that might be involved in tumoral neoangiogenesis and invasiveness.