====== TSP-1 ======
The pathogenesis of [[Cushing's disease]], which is caused by pituitary corticotroph adenoma, remains to be studied. Secreted angioinhibitory factor [[thrombospondin]]-1 (TSP-1) is an adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions and is associated with platelet aggregation, angiogenesis and tumorigenesis. 

Ren et al., found that the expression of TSP-1 is significantly lower in human pituitary corticotroph tumours compared with normal adenohypophysis. 

A study aimed to elucidate the role of TSP-1 in regulating the tumour function of pituitary adenomas. Forced overexpression of TSP-1 in a murine AtT20 pituitary corticotroph tumour cell line decreased corticotroph precursor hormone proopiomelanocortin (POMC) transcription and adrenocorticotropic hormone (ACTH) secretion. Functional studies showed that TSP-1 overexpression in pituitary adenoma cells suppressed proliferation, migration and invasion. We have demonstrated that TSP-1 is a direct target of miR-449c. Further study showed that miR-449c activity enhanced tumorigenesis by directly inhibiting TSP-1 expression. Low expression of lncTHBS1, along with low expression of TSP-1, was associated with the high expression of miR-449c in Cushing's disease patients. Furthermore, RNA-immunoprecipitation associates miR-449c with lncTHBS1 suggesting that lncTHBS1 might be a negative regulator of miR-449c. Taken together, this study has demonstrated that lncTHBS1 might function as competing endogenous RNA for miR-449c, which could suppress the development of Cushing's disease
((Ren J, Gu C, Yang Y, Xue J, Sun Y, Jian F, Chen D, Bian L, Sun Q. TSP-1 is
downregulated and inversely correlates with miR-449c expression in Cushing's
disease. J Cell Mol Med. 2019 Apr 23. doi: 10.1111/jcmm.14297. [Epub ahead of
print] PubMed PMID: 31016850.
)).