BACKGROUND & AIMS: Metastatic gastrointestinal neuroendocrine tumors (NETs) frequently are refractory to chemotherapy. Chemoresistance in various malignancies has been attributed to cancer stem cells (CSCs). We sought to identify gastrointestinal neuroendocrine CSCs (N-CSCs) in surgical specimens and a NET cell line and to characterize novel N-CSC therapeutic targets. METHODS: Human gastrointestinal NETs were evaluated for CSCs using the Aldefluor (Stemcell Technologies, Vancouver, Canada) assay. An in vitro, sphere-forming assay was performed on primary NET cells. CNDT2.5, a human midgut carcinoid cell line, was used for in vitro (sphere-formation) and in vivo (tumorigenicity assays) CSC studies. N-CSC protein expression was characterized using Western blotting. In vivo, systemic short interfering RNA administration targeted Src. RESULTS: By using the Aldefluor assay, aldehyde dehydrogenase-positive (ALDH+) cells comprised 5.8% ± 1.4% (mean ± standard error of the mean) of cells from 19 patient samples. Although many primary cell lines failed to grow, CNDT96 ALDH+ cells formed spheres in anchorage-independent conditions, whereas ALDH- cells did not. CNDT2.5 ALDH+ cells formed spheres, whereas ALDH- cells did not. In vivo, ALDH+ CNDT2.5 cells generated more tumors, with shorter latency than ALDH- or sham-sorted cells. Compared with non-CSCs, ALDH+ cells demonstrated increased expression of activated Src, Erk, Akt, and mammalian target of rapamycin (mTOR). In vivo, anti-Src short interfering RNA treatment of ALDH+ tumors reduced tumor mass by 91%. CONCLUSIONS: CSCs are present in NETs, as shown by in vitro sphere formation and in vivo tumorigenicity assays. Src was activated in N-CSCs and represents a potential therapeutic target in gastrointestinal NETs.
BACKGROUND & AIMS:Metastatic gastrointestinal neuroendocrine tumors (NETs) frequently are refractory to chemotherapy. Chemoresistance in various malignancies has been attributed to cancer stem cells (CSCs). We sought to identify gastrointestinal neuroendocrine CSCs (N-CSCs) in surgical specimens and a NET cell line and to characterize novel N-CSC therapeutic targets. METHODS:Human gastrointestinal NETs were evaluated for CSCs using the Aldefluor (Stemcell Technologies, Vancouver, Canada) assay. An in vitro, sphere-forming assay was performed on primary NET cells. CNDT2.5, a humanmidgut carcinoid cell line, was used for in vitro (sphere-formation) and in vivo (tumorigenicity assays) CSC studies. N-CSC protein expression was characterized using Western blotting. In vivo, systemic short interfering RNA administration targeted Src. RESULTS: By using the Aldefluor assay, aldehyde dehydrogenase-positive (ALDH+) cells comprised 5.8% ± 1.4% (mean ± standard error of the mean) of cells from 19 patient samples. Although many primary cell lines failed to grow, CNDT96 ALDH+ cells formed spheres in anchorage-independent conditions, whereas ALDH- cells did not. CNDT2.5 ALDH+ cells formed spheres, whereas ALDH- cells did not. In vivo, ALDH+ CNDT2.5 cells generated more tumors, with shorter latency than ALDH- or sham-sorted cells. Compared with non-CSCs, ALDH+ cells demonstrated increased expression of activated Src, Erk, Akt, and mammalian target of rapamycin (mTOR). In vivo, anti-Src short interfering RNA treatment of ALDH+ tumors reduced tumor mass by 91%. CONCLUSIONS: CSCs are present in NETs, as shown by in vitro sphere formation and in vivo tumorigenicity assays. Src was activated in N-CSCs and represents a potential therapeutic target in gastrointestinal NETs.
Authors: James C Yao; Catherine Lombard-Bohas; Eric Baudin; Larry K Kvols; Philippe Rougier; Philippe Ruszniewski; Sakina Hoosen; Jessica St Peter; Tomas Haas; David Lebwohl; Eric Van Cutsem; Matthew H Kulke; Timothy J Hobday; Thomas M O'Dorisio; Manisha H Shah; Guillaume Cadiot; Gabriele Luppi; James A Posey; Bertram Wiedenmann Journal: J Clin Oncol Date: 2009-11-23 Impact factor: 44.544
Authors: Michaela S Banck; Rahul Kanwar; Amit A Kulkarni; Ganesh K Boora; Franziska Metge; Benjamin R Kipp; Lizhi Zhang; Erik C Thorland; Kay T Minn; Ramesh Tentu; Bruce W Eckloff; Eric D Wieben; Yanhong Wu; Julie M Cunningham; David M Nagorney; Judith A Gilbert; Matthew M Ames; Andreas S Beutler Journal: J Clin Invest Date: 2013-05-15 Impact factor: 14.808
Authors: Geoffrey Wayne Krampitz; Benson M George; Stephen B Willingham; Jens-Peter Volkmer; Kipp Weiskopf; Nadine Jahchan; Aaron M Newman; Debashis Sahoo; Allison J Zemek; Rebecca L Yanovsky; Julia K Nguyen; Peter J Schnorr; Pawel K Mazur; Julien Sage; Teri A Longacre; Brendan C Visser; George A Poultsides; Jeffrey A Norton; Irving L Weissman Journal: Proc Natl Acad Sci U S A Date: 2016-03-31 Impact factor: 11.205
Authors: Gabriele Capurso; Volker Fendrich; Maria Rinzivillo; Francesco Panzuto; Detlef K Bartsch; Gianfranco Delle Fave Journal: Int J Mol Sci Date: 2012-12-20 Impact factor: 5.923