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- Li, Su-Chen, et al.
(författare)
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The Somatostatin Analogue Octreotide Inhibits Growth of Small Intestine Neuroendocrine Tumour Cells
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:10, s. e48411-
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Tidskriftsartikel (refereegranskat)abstract
- Octreotide is a widely used synthetic somatostatin analogue that significantly improves the management of neuroendocrine tumours (NETs). Octreotide acts through somatostatin receptors (SSTRs). However, the molecular mechanisms leading to successful disease control or symptom management, especially when SSTRs levels are low, are largely unknown. We provide novel insights into how octreotide controls NET cells. CNDT2.5 cells were treated from 1 day up to 16 months with octreotide and then were profiled using Affymetrix microarray analysis. Quantitative real-time PCR and western blot analyses were used to validate microarray profiling in silico data. WST-1 cell proliferation assay was applied to evaluate cell growth of CNDT2.5 cells in the presence or absence of 1 μM octreotide at different time points. Moreover, laser capture microdissected tumour cells and paraffin embedded tissue slides from SI-NETs at different stages of disease were used to identify transcriptional and translational expression. Microarrays analyses did not reveal relevant changes in SSTR expression levels. Unexpectedly, six novel genes were found to be upregulated by octreotide: annexin A1 (ANXA1), rho GTPase-activating protein 18 (ARHGAP18), epithelial membrane protein 1 (EMP1), growth/differentiation factor 15 (GDF15), TGF-beta type II receptor (TGFBR2) and tumour necrosis factor (ligand) superfamily member 15 (TNFSF15). Furthermore, these novel genes were expressed in tumour tissues at transcript and protein levels. We suggest that octreotide may use a potential novel framework to exert its beneficial effect as a drug and to convey its action on neuroendocrine cells. Thus, six novel genes may regulate cell growth and differentiation in normal and tumour neuroendocrine cells and have a role in a novel octreotide mechanism system.
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| 2. |
- Marina, Djordje, et al.
(författare)
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Truncated somatostatin receptor 5 may modulate therapy response to somatostatin analogues - Observations in two patients with acromegaly and severe headache
- 2015
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Ingår i: Growth Hormone & IGF Research. - : Elsevier BV. - 1096-6374 .- 1532-2238. ; 25:5, s. 262-267
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Tidskriftsartikel (refereegranskat)abstract
- Background: Somatotropinomas have unique "fingerprints" of somatostatin receptor (sst) expression, which are targets in treatment of acromegaly with somatostatin analogues (SSAs). However, a significant expression of sst is not always related to the biochemical response to SSAs. Headache is a common complaint in acromegaly and considered a clinical marker of disease activity. SSAs are reported to have an own analgesic effect, but the sst involved are unknown. Patients and methods: We investigated sst expression in two acromegalic patients with severe headache and no biochemical effects of octreotide, but a good response to pasireotide. We searched the literature for determinants of biochemical and analgesic effects of SSAs in somatotropinomas. Results: Case 1 had no biochemical or analgesic effects of octreotide, a semi-selective SSA, but a rapid and significant effect of pasireotide, a pan-SSA Case 2 demonstrated discordance between analgesic and biochemical effects of octreotide, in that headache disappeared, but without biochemical improvement. In contrast, pasireotide normalized insulin-like growth factor 1. Both adenomas were sparsely granulated and had strong membranous expressions of sst2a in 50-75% and sst5 in 75-100% of tumor cells. The truncated sst5 variant TMD4 (sst5TMD4) showed expression in 20-57% of tumor cells. Conclusions: A poor biochemical response to octreotide may be associated with tumor expression of a truncated sst5 variant, despite abundant sst2a expression, suggesting an influence from variant sst5 on common sst signaling pathways. Furthermore, unrelated analgesic and biochemical effects of SSAs supported a complex pathogenesis of acromegaly-associated headache. Finally, assessment of truncated sst5 in addition to full length sst could be important for a choice of postoperative SSA treatment in somatotropinomas.
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