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Gene/Protein
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Target Concepts:
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Query: UNIPROT:P42345 (
mTOR
)
26,049
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Thyroid cancer incidence is rapidly increasing.
Papillary Thyroid Carcinoma
(
PTC
), the most frequent hystotype, usually displays good prognosis, but no effective therapeutic options are available for the fraction of progressive
PTC
patients. BRAF and RET/
PTC
are the most frequent driving genetic lesions identified in
PTC
. We developed two complementary in vitro models based on RET/PTC1 oncogene, starting from the hypothesis that miRNAs modulated by a driving
PTC
-oncogene are likely to have a role in thyroid neoplastic processes. Through this strategy, we identified a panel of deregulated miRNAs. Among these we focused on miR-199a-3p and showed its under-expression in
PTC
specimens and cell lines. We demonstrated that miR-199a-3p restoration in
PTC
cells reduces MET and
mTOR
protein levels, impairs migration and proliferation and, more interesting, induces lethality through an unusual form of cell death similar to methuosis, caused by macropinocytosis dysregulation. Silencing MET or
mTOR
, both involved in survival pathways, does not recapitulate miR-199a-3p-induced cell lethality, thus suggesting that the cooperative regulation of multiple gene targets is necessary. Integrated analysis of miR-199a-3p targets unveils interesting networks including HGF and macropinocytosis pathways. Overall our results indicate miR-199a-3p as a tumor suppressor miRNA in
PTC
.
...
PMID:miR-199a-3p displays tumor suppressor functions in papillary thyroid carcinoma. 2481 Mar 36
Papillary Thyroid Carcinoma
(
PTC
) is the most frequent thyroid cancer. Although several
PTC
-specific miRNA profiles have been reported, only few upregulated miRNAs are broadly recognized, while less consistent data are available about downregulated miRNAs. In this study we investigated miRNA deregulation in
PTC
by miRNA microarray, analysis of a public dataset from The Cancer Genome Atlas (TCGA), literature review and meta-analysis based on a univocal miRNA identifier derived from miRBase v21. A list of 18 miRNAs differentially expressed between
PTC
and normal thyroid was identified and validated in the TCGA dataset. Furthermore, we compared our signature with miRNA profiles derived from 15 studies selected from literature. Then, to select possibly functionally relevant miRNA, we integrated our miRNA signature with those from two in vitro cell models based on the
PTC
-driving oncogene RET/PTC1. Through this strategy, we identified commonly deregulated miRNAs, including miR-451a, which emerged also by our meta-analysis as the most frequently reported downregulated miRNA. We showed that lower expression of miR-451a correlates with aggressive clinical-pathological features of
PTC
as tall cell variant, advanced stage and extrathyroid extension. In addition, we demonstrated that ectopic expression of miR-451a impairs proliferation and migration of two
PTC
-derived cell lines, reduces the protein levels of its recognized targets MIF, c-MYC and AKT1 and attenuates AKT/
mTOR
pathway activation.Overall, our study provide both an updated overview of miRNA deregulation in
PTC
and the first functional evidence that miR-451a exerts tumor suppressor functions in this neoplasia.
...
PMID:miR-451a is underexpressed and targets AKT/mTOR pathway in papillary thyroid carcinoma. 2955 31