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- Arvidsson, Yvonne, 1960, et al.
(författare)
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Hypoxia stimulates CXCR4 signalling in ileal carcinoids.
- 2010
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Ingår i: Endocrine-related cancer. - 1479-6821. ; 17:2, s. 303-316
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Tidskriftsartikel (refereegranskat)abstract
- Tumour hypoxia is associated with increased metastatic potential and resistance to radiotherapy and chemotherapy. Ileal carcinoids are usually metastatic at the time of diagnosis and respond poorly to chemotherapy. The aim of this study was to investigate the extent of hypoxia in ileal carcinoids and the response of tumour cells to induced hypoxia. VEGF, CA-IX, HIF-1alpha and HIF-2alpha were studied by immunohistochemistry in biopsies from 24 patients with ileal carcinoids. All hypoxic markers were shown to be highly expressed in localized areas of the tumours irrespective of tumour location or stage. However, HIF-2alpha expression was significantly higher in distant metastases compared to primary tumours in the same patient. Global gene expression profiling of GOT1 carcinoid cells revealed a marked response to hypoxia. Expression of genes related to epithelial-to-mesenchymal transition (EMT) and development was altered including increased expression of the chemokine receptor CXCR4, an important regulator of invasive growth and metastasis formation. High expression of CXCR4 was confirmed by immunohistochemistry in tumour biopsies. Stimulation of GOT1 cells by the CXCR4 ligand CXCL12 (SDF-1) activated the MAPK p42/44 signalling pathway and increased tumour cell migration. We conclude that ileal carcinoids contain hypoxic areas expressing HIF-1alpha, and HIF-2alpha and CXCR4. Signalling through the CXCL12-CXCR4 axis may contribute to the metastatic potential of ileal carcinoids. Targeting of HIFs and/or the CXCR4 signalling pathway may offer new therapeutic strategies for this carcinoid tumour disease.
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| 2. |
- Arne, Gabriella, et al.
(författare)
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Gastrointestinal stromal tumors (GISTs) express somatostatin receptors and bind radiolabeled somatostatin analogs.
- 2013
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Ingår i: Acta oncologica (Stockholm, Sweden). - 1651-226X .- 0284-186X. ; 52:4, s. 783-792
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Tidskriftsartikel (refereegranskat)abstract
- Background. Gastrointestinal stromal tumors (GISTs) can be effectively treated with tyrosine kinase inhibitors (TKIs). However, some patients with GIST develop drug resistance, and alternative treatment strategies are therefore needed. The aim of this study was to analyze the expression of somatostatin receptors (SSTR) in GIST as a target for peptide receptor-mediated radiotherapy (PRRT). Material and methods. Expression profiling of SSTR1-5 was performed on biopsies from 34 GISTs (16 gastric tumors, 15 small intestinal tumors, and three rectal tumors). SSTR scintigraphy ((111)In-octreotide) and measurement of (111)In activity in tumor specimens was performed in seven patients. Uptake and internalization of (177)Lu- octreotate was studied in primary cell cultures from two patients. Results. Quantitative PCR analysis showed expression of SSTR1 and SSTR2 in the majority of tumors, while SSTR3-5 were expressed at low levels. Immunohistochemical analysis confirmed the presence of SSTR1 and SSTR2 proteins in all GISTs, and SSTR3-5 in a subset of tumors. Diagnostic imaging by SSTR scintigraphy, using (111)In-octreotide, demonstrated tumor uptake of (111)In in three of six GIST patients. Measurement of (111)In activity in excised tumor specimens from five patients gave tumor-to-blood (T/B) activity ratios of between eight and 96. Tumor cells in primary culture (gastric and small intestinal GIST) specifically bound and internalized (177)Lu when incubated with the therapeutic compound (177)Lu-octreotate for 4-48 hours (p < 0.05). Conclusion. Peptide receptor-mediated radiotherapy via SSTR may provide a novel treatment strategy in carefully selected GIST patients with TKI-resistant tumors.
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| 5. |
- Nilsson, Ola, 1957, et al.
(författare)
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New medical strategies for midgut carcinoids.
- 2010
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Ingår i: Anti-cancer agents in medicinal chemistry. - 1875-5992. ; 10:3, s. 250-269
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Forskningsöversikt (refereegranskat)abstract
- Patients with well-differentiated neuroendocrine tumours of the gastrointestinal tract often present with metastases and hormonal symptoms. These patients can be palliated by interventional tumour reduction and medical treatment with somatostatin analogues; no effective chemotherapy is available. Radionuclide therapy via somatostatin receptors is one new therapeutic alternative. The recognition that neuroendocrine tumours express specific receptors for growth factors and chemokines, which are of importance for tumour growth, vascularization, and spread, may open the way for new therapeutic approaches. The signalling pathways in carcinoid tumours are incompletely explored. This review summarizes potential new treatment strategies from clinical and experimental studies, e.g. inhibition of angiogenesis, targeting of growth factors or their receptors by tyrosine kinase inhibitors, interference with specific cellular pathways (mTOR, PI3K, RAS/RAF, Notch), and also inhibition of the proteasome and histone deacetylation. Combining targeted therapy with chemotherapy, or using drugs to sensitize for radionuclide therapy, may enhance the treatment outcome.
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