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- Spetz, Johan, et al.
(författare)
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Effects of internal irradiation from 177Lu-octreotate on transcriptional expression in GOT1 midgut carcinoid in nude mice
- 2014
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Ingår i: SweRays Workshop, Malmö, Sweden, Aug 20-22.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Neuroendocrine (NE) tumors expressing somatostatin receptors (SSTR) are often treated with 177Lu-octreotate. The treatment is highly successful in animal models, but low cure rates in clinical studies suggests optimization of treatment protocol is needed. Little is known about which cellular responses play a crucial role in neuroendocrine tumors after irradiation. It is therefore important to identify the effects of 177Lu-octreotate on biological functions for future optimization of treatment parameters and the identification of biomarkers predicting treatment response. The aim of this study was to investigate the transcriptional response of GOT1 midgut carcinoid in nude mice following 177Lu-octreotate treatment. Methods: GOT1 bearing BALB/c nude mice were i.v. injected with 15 MBq 177Lu-octreotate and tumor size was measured twice a week using calipers. Animals were killed after 1, 3, 7 or 41 days and tumor samples excised and snap frozen in liquid nitrogen. Total RNA was extracted from tumor samples and subjected to Illumina microarray expression analysis. Differential transcriptional profiles were identified by comparing treated and untreated tumor samples using Nexus Expression 3.0 software. Associated biological functions and biological pathways (according to Gene Ontology terms) were compared using Nexus Expression 3.0 and Ingenuity IPA. Results: The mean tumor volume was clearly reduced after 177Lu-octreotate treatment. Microarray analysis showed clear difference in regulation pattern between the time points. The analysis of associated biological functions revealed clear effect on cell death and survival, and cell cycle after 1, 3, and 7 days, while cellular movement and cellular development were clearly influenced after 41 days. Cellular growth and proliferation was also affected after 1 day but not at the other time points studied. Conclusions: : Analysis of the transcriptional regulation in GOT1 tumors in nude mice following 177Lu-octreotate treatment revealed responses in different cellular functions that were distinct for each time point. These findings indicate potential venues for increasing clinical effectiveness of midgut carcinoid therapy with 177Lu-octreotate.
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| 4. |
- Spetz, Johan, et al.
(författare)
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Transcriptional effects of Lu-177-octreotate therapy using a priming treatment schedule on GOT1 tumor in nude mice
- 2019
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Ingår i: Ejnmmi Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background(177)Lu-octreotate is used for therapy of somatostatin receptor expressing neuroendocrine tumors with promising results, although complete tumor remission is rarely seen. Previous studies on nude mice bearing the human small intestine neuroendocrine tumor, GOT1, have shown that a priming injection of Lu-177-octreotate 24h before the main injection of Lu-177-octreotate resulted in higher Lu-177 concentration in tumor, resulting in increased absorbed dose, volume reduction, and time to regrowth. To our knowledge, the cellular effects of a priming treatment schedule have not yet been studied. The aim of this study was to identify transcriptional changes contributing to the enhanced therapeutic response of GOT1 tumors in nude mice to Lu-177-octreotate therapy with priming, compared with non-curative monotherapy.ResultsRNA microarray analysis was performed on tumor samples from GOT1-bearing BALB/c nude mice treated with a 5MBq priming injection of Lu-177-octreotate followed by a second injection of 10MBq of Lu-177-octreotate after 24h and killed after 1, 3, 7, and 41days after the last injection. Administered activity amounts were chosen to be non-curative, in order to facilitate the study of tumor regression and regrowth. Differentially regulated transcripts (RNA samples from treated vs. untreated animals) were identified (change 1.5-fold; adjusted p value <0.01) using Nexus Expression 3.0. Analysis of the biological effects of transcriptional regulation was performed using the Gene Ontology database and Ingenuity Pathway Analysis. Transcriptional analysis of the tumors revealed two stages of pathway regulation for the priming schedule (up to 1week and around 1month) which differed distinctly from cellular responses observed after monotherapy. Induction of cell cycle arrest and apoptotic pathways (intrinsic and extrinsic) was found at early time points after treatment start, while downregulation of pro-proliferative genes were found at a late time point.ConclusionsThe present study indicates increased cellular stress responses in the tumors treated with a priming treatment schedule compared with those seen after conventional Lu-177-octreotate monotherapy, resulting in a more profound initiation of cell cycle arrest followed by apoptosis, as well as effects on PI3K/AKT-signaling and unfolded protein response.
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| 5. |
- Langen, Britta, et al.
(författare)
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Microarray Studies on 211At Administration in BALB/c Nude Mice Indicate Systemic Effects on Transcriptional Regulation in Non-Thyroid Tissues
- 2017
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 58:2, s. 346-353
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Targeted α-therapy is a promising treatment option for various types of malignant tumors. Radiolabeled cancer-seeking agents, however, undergo degradation resulting in a certain percentage of free radionuclide in the body. The radiohalogen 211At accumulates in various tissues with specifically high uptake in the thyroid. When normal thyroid function is disturbed due to ionizing radiation (IR) exposure, deleterious effects can occur in tissues that depend on thyroid hormone (TH) regulation for normal physiological function. However, knowledge of systemic effects is still rudimentary. We previously reported similarities in transcriptomic regulation between the thyroid and other tissues despite large differences in absorbed dose from 211At (Langen et al. JNM, 2013). Here, we present supportive evidence on systemic effects after 211At administration. Methods: Expression microarray data from kidney cortex and medulla, liver, lungs, and spleen were used from previous studies where mice were i.v. injected with 0.064–42 kBq 211At and killed after 24 h, or injected with 1.7 kBq 211At and killed after 1, 6, or 168 h. Controls were mock-treated and killed after 24 h. Literature-based gene signatures were used to evaluate the relative impact from IR- or TH-induced regulation. Thyroid- and TH-associated upstream regulators as well as thyroid-related diseases and functions were generated using functional analysis software. Results: Responses in IR- or TH-associated gene signatures were tissue-specific, varied over time, and the relative impact of each gene signature differed between the investigated tissues. The liver showed a clear dominance of TH-responding genes. In the kidney cortex, kidney medulla, and lungs, the TH-associated signature was detected to at least similar extent as the IR-associated signature. The spleen was the single tissue showing regulation of only IR-associated signature genes. Various thyroid-associated diseases and functions were inferred from the data: L-triiodothyronine, TH, TH receptor, and triiodothyronine (reverse) were inferred as upstream-regulators with differences in incidence and strength of regulation depending on tissue type. Conclusion: These findings indicate that transcriptional regulation in various non-thyroid tissues was–in part–induced by thyroid (hormone)-dependent signaling. Consideration of the systemic context between tissues could contribute to normal tissue risk assessment and planning of remedial measures.
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- Langen, Britta, et al.
(författare)
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Transcriptional response in normal mouse tissues after i.v. 211At administration - response related to absorbed dose, dose rate, and time
- 2015
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Ingår i: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X .- 2191-219X. ; 5:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Background In cancer radiotherapy, knowledge of normal tissue responses and toxicity risks is essential in order to deliver the highest possible absorbed dose to the tumor while maintaining normal tissue exposure at non-critical levels. However, few studies have investigated normal tissue responses in vivo after 211At administration. In order to identify molecular biomarkers of ionizing radiation exposure, we investigated genome-wide transcriptional responses to (very) low mean absorbed doses from 211At in normal mouse tissues. Methods Female BALB/c nude mice were intravenously injected with 1.7 kBq 211At and killed after 1 h, 6 h, or 7 days or injected with 105 or 7.5 kBq and killed after 1 and 6 h, respectively. Controls were mock-treated. Total RNA was extracted from tissue samples of kidney cortex and medulla, liver, lungs, and spleen and subjected to microarray analysis. Enriched biological processes were categorized after cellular function based on Gene Ontology terms. Results Responses were tissue-specific with regard to the number of significantly regulated transcripts and associated cellular function. Dose rate effects on transcript regulation were observed with both direct and inverse trends. In several tissues, Angptl4, Per1 and Per2, and Tsc22d3 showed consistent transcript regulation at all exposure conditions. Conclusions This study demonstrated tissue-specific transcriptional responses and distinct dose rate effects after 211At administration. Transcript regulation of individual genes, as well as cellular responses inferred from enriched transcript data, may serve as biomarkers in vivo. These findings expand the knowledge base on normal tissue responses and may help to evaluate and limit side effects of radionuclide therapy. Keywords: Astatine-211; Ionizing radiation; Normal tissue response; Radionuclide therapy; Biomarke
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| 10. |
- Spetz, Johan, et al.
(författare)
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Fractionated 177Lu-octreotate therapy of human GOT1 tumors in nude mice increases treatment efficacy, possibly via SSTR up-regulation
- 2014
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Ingår i: 3rd Swedish Cancer Research Meeting, Stockholm, Sweden, September 2-3, 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: The radiolabelled somatostatin analogue 177Lu-octreotate is a promising treatment option for malignant neuroendocrine tumors that overexpress somatostatin receptors. The human midgut carcinoid GOT1 cell line has shown promising treatment response to 177Lu-octreotate in xenografted mice. In clinical studies, however, only low cure rates have been achieved to date. In vitro and preclinical in vivo studies have shown that irradiation can up-regulate the expression of somatostatin receptors and thereby give an increased uptake of 177Lu-octreotate. The cellular processes that underlie positive treatment response to 177Lu-octreotate are otherwise largely unknown. Genome-wide analysis of tumor cell responses in this successful mouse model offers a venue to identify critical treatment parameters and to optimize clinical effectiveness of 177Lu-octreotate therapy. Aim: To investigate the genome-wide transcriptional response of xenografted GOT1 midgut carcinoid after fractionated treatment giving a priming administration before the main administration of 177Lu-octreotate. Methods: GOT1 bearing BALB/c nude mice were i.v. injected with 5, 10, 15 or 30 MBq 177Lu-octreotate. The groups receiving 5 and 10 MBq 177Lu-octreotate were given an additional 10 or 5 MBq 177Lu-octreotate 24 h after the first injection, respectively. Control animals were injected with NaCl. Animals were killed after 1, 3, 7 or 41 days for the 5+10, 10+5 and 15 MBq treatments and controls and after 41 days for the 30 MBq treatment. Tumor samples were excised and snap frozen in liquid nitrogen, followed by total RNA extraction. Microarray analysis was performed on samples from treated animals and untreated controls (Illumina HumanHT-12 Beadchips) and differentially regulated transcripts were identified (change, ≥1.5-fold; P-adjusted < 0.05). Associated biological functions and affected biological pathways (according to Gene Ontology terms, P-adjusted < 0.05) were analyzed using Nexus Expression and Ingenuity IPA. Results: The mean tumor volume was clearly reduced after 177Lu-octreotate treatment in all groups. The mean absorbed dose to the tumor tissue was almost 110 % higher for the 5+10 MBq than for the 15 MBq group. The best overall therapeutic effects were obtained in the 5+10 MBq group. Microarray analysis showed clear differences in transcriptional response between treated groups and time points. Affected associated biological processes were e.g. cell death and survival, and cell cycle regulation after 1, 3, and 7 days; cellular movement and cellular development were influenced after 41 days. Cellular growth and proliferation was affected after 1 day but not at later time points. Conclusions: Microarray analysis of 177Lu-octreotate-induced effects in xenografted GOT1 tumors showed distinct differences in transcriptional responses and associated cellular functions, both with regard to treatment fractionation and time-of-response. The use of priming activity offers a new venue for increasing clinical effectiveness of 177Lu-octreotate therapy of midgut carcinoid tumors, probably due to increased somatostatin receptor expression.
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