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mTOR kinase inhibition reduces tissue factor expression and growth of pancreatic neuroendocrine tumors
Author(s) -
Lewis C. S.,
Elnakat Thomas H.,
OrrAsman M. A.,
Green L. C.,
Boody R. E.,
Matiash K.,
Karve A.,
Hisada Y. M.,
Davis H. W.,
Qi X.,
Mercer C. A.,
Lucas F. V.,
Aronow B. J.,
Mackman N.,
Versteeg H. H.,
Bogdanov V. Y.
Publication year - 2019
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.14342
Subject(s) - mtorc1 , pi3k/akt/mtor pathway , cancer research , tissue factor , biology , growth factor , gene knockdown , cell growth , cell culture , microbiology and biotechnology , signal transduction , medicine , receptor , biochemistry , genetics , coagulation
Essentials Tissue factor (TF) isoforms are expressed in pancreatic neuroendocrine tumors (pNET). TF knockdown inhibits proliferation of human pNET cells in vitro . mTOR kinase inhibitor sapanisertib/MLN0128 suppresses TF expression in human pNET cells. Sapanisertib suppresses TF expression and activity and reduces the growth of pNET tumors in vivo .Summary Background Full‐length tissue factor (fl TF ) and alternatively spliced TF (as TF ) contribute to growth and spread of pancreatic ductal adenocarcinoma. It is unknown, however, if fl TF and/or as TF contribute to the pathobiology of pancreatic neuroendocrine tumors ( pNETs ). Objective To assess TF expression in pNETs and the effects of mTOR complex 1/2 ( mTORC 1/2) inhibition on pNET growth. Methods Human pNET specimens were immunostained for TF . Human pNET cell lines QGP 1 and BON were evaluated for TF expression and responsiveness to mTOR inhibition. sh RNA were used to knock down TF in BON . TF cofactor activity was assessed using a two‐step FX a generation assay. TF promoter activity was assessed using transient transfection of human TF promoter‐driven reporter constructs into cells. Mice bearing orthotopic BON tumors were treated with the mTORC 1/2 ATP site competitive inhibitor sapanisertib/ MLN 0128 (3 mg kg −1 , oral gavage) for 34 days. Results Immunostaining of pNET tissue revealed fl TF and as TF expression. BON and QGP 1 expressed both TF isoforms, with BON exhibiting higher levels. sh RNA directed against TF suppressed BON proliferation in vitro . Treatment of BON with sapanisertib inhibited mTOR signaling and suppressed TF levels. BON tumors grown in mice treated with sapanisertib had significantly less TF protein and cofactor activity, and were smaller compared with tumors grown in control mice. Conclusions TF isoforms are expressed in pNET s. Sapanisertib suppresses TF mRNA and protein expression as well as TF cofactor activity in vitro and in vivo . Thus, further studies are warranted to evaluate the clinical utility of TF ‐suppressing mTORC 1/2 inhibitor sapanisertib in pNET management.