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  • 1
    In: Neuroendocrinology, S. Karger AG, Vol. 113, No. 5 ( 2023), p. 501-518
    Abstract: 〈 b 〉 〈 i 〉 Introduction: 〈 /i 〉 〈 /b 〉 Cancer-associated fibroblasts (CAF) have been identified as relevant contributors to cancer progression and drug resistance in many tumors. Although neuroendocrine tumors (NET) are often associated with a strong stromal reaction, no study has addressed whether CAF are involved in progression and therapeutic resistance in NET. The aim of this study was to characterize the role of CAF in NET. 〈 b 〉 〈 i 〉 Methods: 〈 /i 〉 〈 /b 〉 We established primary CAF cultures derived from NET liver metastases to study the effect on NET cell lines NT-3 and BON. Immunohistochemistry was performed on tissue sections of primary and metastatic NET tissue. 〈 b 〉 〈 i 〉 Results: 〈 /i 〉 〈 /b 〉 Immunohistochemistry identified CAF dispersed in between tumor cells and within fibrotic bands separating tumor cell clusters in NET. Stimulating NET cells with CAF decreased expression of SSTR2 and 〈 i 〉 chromogranin A 〈 /i 〉 and induced expression of 〈 i 〉 CXCR4 〈 /i 〉 . CAF induced a 2.3-fold increase in proliferation and completely reversed the response to everolimus in NT-3 cells. We identified STAT3 as the main signaling pathway induced by CAF. STAT3 targeting by small interfering RNA knockdown and inhibitors prevented CAF-induced proliferation and restored everolimus responsiveness. STAT3 activation in NET tissue was associated with decreased chromogranin A expression, increased Ki-67 index, and decreased 5-year overall and progression-free survival. CAF directly influence proliferation and therapeutic response in NET cells. 〈 b 〉 〈 i 〉 Conclusion: 〈 /i 〉 〈 /b 〉 Identifying STAT3 as the contributing pathway of this so far neglected tumor-stroma interaction has the potential to become a new therapeutic target to halt tumor growth and to restore therapeutic responsiveness in NET.
    Type of Medium: Online Resource
    ISSN: 0028-3835 , 1423-0194
    Language: English
    Publisher: S. Karger AG
    Publication Date: 2023
    detail.hit.zdb_id: 1483028-0
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  • 2
    In: Cellular Oncology, Springer Science and Business Media LLC, Vol. 45, No. 6 ( 2022-12), p. 1401-1419
    Abstract: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) form a rare and remarkably heterogeneous group of tumors. Therefore, establishing personalized therapies is eminently challenging. To achieve progress in preclinical drug development, there is an urgent need for relevant tumor models. Methods We successfully established three gastroenteropancreatic neuroendocrine tumor (GEP-NET) cell lines (NT-18P, NT-18LM, NT-36) and two gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) cell lines (NT-32 and NT-38). We performed a comprehensive characterization of morphology, NET differentiation, proliferation and intracellular signaling pathways of these five cell lines and, in addition, of the NT-3 GEP-NET cell line. Additionally, we conducted panel sequencing to identify genomic alterations suitable for mutation-based targeted therapy. Results We found that the GEP-NEN cell lines exhibit a stable neuroendocrine phenotype. Functional kinome profiling revealed a higher activity of serine/threonine kinases (STK) as well as protein tyrosine kinases (PTK) in the GEP-NET cell lines NT-3 and NT-18LM compared to the GEP-NEC cell lines NT-32 and NT-38. Panel sequencing revealed a mutation in Death Domain Associated Protein (DAXX), sensitizing NT-18LM to the Ataxia telangiectasia and Rad3 related (ATR) inhibitor Berzosertib, and a mutation in AT-Rich Interaction Domain 1A (ARID1A), sensitizing NT-38 to the Aurora kinase A inhibitor Alisertib. Small interfering RNA-mediated knock down of DAXX in the DAXX wild type cell line NT-3 sensitized these cells to Berzosertib. Conclusions The newly established GEP-NET and GEP-NEC cell lines represent comprehensive preclinical in vitro models suitable to decipher GEP-NEN biology and pathogenesis. Additionally, we present the first results of a GEP-NEN-specific mutation-based targeted therapy. These findings open up new potentialities for personalized therapies in GEP-NEN.
    Type of Medium: Online Resource
    ISSN: 2211-3428 , 2211-3436
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2595105-1
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  • 3
    In: Molecular Cancer Research, American Association for Cancer Research (AACR), Vol. 16, No. 3 ( 2018-03-01), p. 496-507
    Abstract: Clinical options for systemic therapy of neuroendocrine tumors (NET) are limited. Development of new drugs requires suitable representative in vitro and in vivo model systems. So far, the unavailability of a human model with a well-differentiated phenotype and typical growth characteristics has impaired preclinical research in NET. Herein, we establish and characterize a lymph node–derived cell line (NT-3) from a male patient with well-differentiated pancreatic NET. Neuroendocrine differentiation and tumor biology was compared with existing NET cell lines BON and QGP-1. In vivo growth was assessed in a xenograft mouse model. The neuroendocrine identity of NT-3 was verified by expression of multiple NET-specific markers, which were highly expressed in NT-3 compared with BON and QGP-1. In addition, NT-3 expressed and secreted insulin. Until now, this well-differentiated phenotype is stable since 58 passages. The proliferative labeling index, measured by Ki-67, of 14.6% ± 1.0% in NT-3 is akin to the original tumor (15%–20%), and was lower than in BON (80.6% ± 3.3%) and QGP-1 (82.6% ± 1.0%). NT-3 highly expressed somatostatin receptors (SSTRs: 1, 2, 3, and 5). Upon subcutaneous transplantation of NT-3 cells, recipient mice developed tumors with an efficient tumor take rate (94%) and growth rate (139% ± 13%) by 4 weeks. Importantly, morphology and neuroendocrine marker expression of xenograft tumors resembled the original human tumor. Implications: High expression of somatostatin receptors and a well-differentiated phenotype as well as a slow growth rate qualify the new cell line as a relevant model to study neuroendocrine tumor biology and to develop new tumor treatments. Mol Cancer Res; 16(3); 496–507. ©2018 AACR.
    Type of Medium: Online Resource
    ISSN: 1541-7786 , 1557-3125
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
    detail.hit.zdb_id: 2097884-4
    SSG: 12
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