| 1. |
- AHLSTEDT, JONATAN, et al.
(författare)
-
Effect of Blockade of Indoleamine 2, 3-dioxygenase in Conjunction with Single Fraction Irradiation in Rat Glioma
- 2015
-
Ingår i: Jacobs journal of radiation oncology. - 2376-9424. ; 2:3
-
Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma (GBM), or WHO Astrocytoma grade IV, is the most common primary brain tumour in adults. GBM is shown to escape host immune surveillance through many paths, of which expression of indoleamine 2,3-dioxygenase (IDO), leading to induction and accumulation of regulatory T-cells in the tumour microenvironment, has been shown to be of importance. 1-Methyl tryptophan (1-MT) is an inhibitor of IDO that has been shown to have a positive effect on survival in experimental models of GBM. In this study, we evaluate the effect of combined single-fraction irradiation of 8 Gy with 1-MT treatment in Fischer rats carrying the RG2 glioma model. We also investigate expression of IDO in the RG2 model before and after irradiation. Thirty-three Fischer 344 rats received intracranial inoculations of RG2 tumour cells, and were treated with either intraperito-neal 1-MT, 8 Gy single-fraction radiotherapy, or a combination of the two. Survival in the combined treatment group (29 days ± 0.75) was significantly better than controls (20 ± 0.99, p=0.015) and radiation only (17 ± 2.75, p=0.014). Survival was also better with combined treatment compared to 1-MT only but the difference was non-significant (18 ± 0.28, p=0.215).Our results add to the growing base of evidence suggesting 1-methyl-tryptophan is an attractive candidate for clinical investi-gation in patients carrying highly malignant astrocytoma, especially in combination with radiation treatment, even in singular fraction settings.
|
|
| 2. |
- Ahlstedt, Jonatan, et al.
(författare)
-
Growth pattern of experimental glioblastoma
- 2020
-
Ingår i: Histology and Histopathology. - 1699-5848. ; 35:8, s. 871-886
-
Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma multiforme (GBM) is an aggressive primary brain malignancy with a very poor prognosis. Researchers employ animal models to develop potential therapies. It is important that these models have clinical relevance. This means that old models, propagated for decades in cultures, should be questioned. Parameters to be evaluated include whether animals are immune competent or not, the infiltrative growth pattern of the tumor, tumor volume resulting in symptoms and growth rate.We here describe the growth pattern of an experimental glioblastoma model in detail with GFP positive glioblastoma cells in fully immune competent animalsand study tumor growth rate and tumor mass as a function of time from inoculation.We were able to correlate findings made with classical immunohistochemistry and MR findings. The tumor growth rate was fitted by a Gompertz function. The model predicted the time until onset of symptoms for 5000 inoculated cells to 18.7±0.4 days, and the tumor mass at days 10 and 14, which are commonly used as the start of treatment in therapeutic studies, were 5.97±0.62 mg and 29.1±3.0 mg, respectively.We want to raise the question regarding the clinical relevance of the outline of glioblastoma experiments, where treatment is ofteninitiated at a very early stage. The approach presented here could potentially be modified to gain information also from other tumor models.
|
|
| 3. |
- Ahlstedt, Jonatan, et al.
(författare)
-
Increased effect of two-fraction radiotherapy in conjunction with IDO1 inhibition in experimental glioblastoma
- 2020
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:5
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of the study was to investigate therapeutic efficacy of single-or two-fraction radiotherapy in conjunction with IDO1-inhibition in a syngeneic rat glioblastoma model. IDO is known to cause immunosuppression through breakdown of tryptophan in the tumor microenvironment. Methods Gene expression analyses of IDO in glioblastoma were performed with data from publicly available datasets. Fractionation studies were done on animals to evaluate tumor size, immune cell infiltration of tumors and serum profile on day 18 after tumor inoculation. Survival analyses were done with animals carrying intracranial glioblastomas comparing twofraction radiotherapy+IDO1-inhibition to controls. IDO inhibition was achieved by administration of 1-methyl tryptophan (1-MT), and radiotherapy (RT) was delivered in doses of 8Gy. Results The expression of IDO1 was increased on gene level in glioblastoma stem cells. Tumor size was significantly reduced in animals treated with 1-MT+RTx 2 (both long and short intervals, i.e. 7 and 4 days between the treatments) as compared to control animals, animals treated with only 1-MT or animals treated with 1-MT+RTx1. Serum levels of IL-1A were significantly altered in all treated animals as compared to control animals. Survival was significantly increased in the animals treated with 1-MT+RTx2 (7-day interval) compared to control animals. Conclusions Addition of two-fraction RT to IDO1 inhibition with 1-MT significantly reduced tumor size in animals with glioblastoma. Survival was significantly increased in animals treated with twofractioned RT+1-MT as compared to untreated controls increased significantly. Advances in knowledge The currently used combination of only two fractions of radiotherapy and immune therapy is a promising area of research, increasing efficacy compared to single fraction irradiation, while potentially lowering radiation side effects compared to radiation in current clinical practice.
|
|
| 4. |
- Chakwizira, Arthur, et al.
(författare)
-
Mathematical modelling of the synergistic combination of radiotherapy and indoleamine-2,3-dioxygenase (IDO) inhibitory immunotherapy against glioblastoma
- 2018
-
Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 91:1087
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Recent research has shown that combining radiotherapy and immunotherapy can counteract the ability of cancer to evade and suppress the native immune system. To optimise the synergy of the combined therapies, factors such as radiation dose and fractionation must be considered, alongside numerous parameters resulting from the complexity of cancer-immune system interactions. It is instructive to use mathematical models to tackle this problem. Methods: In this work, we adapted a model primarily to describe the synergistic effect between single-fraction radiotherapy and immunotherapy (1-methyl tryptophan) observed in previous experiments with glioblastoma-carrying rats. We also showed how the model can be used to generate hypotheses on the outcome of other treatment fractionation schemes. Results: The model successfully reproduced the results of the experiments. Moreover, it provided support for the hypothesis that, for a given biologically effective dose, the efficacy of the combination therapy and the synergy between the two therapies are favoured by the administration of radiotherapy in a hypofractionated regime. Furthermore, for a double-fraction irradiation regimen, the synergy is favoured by a short time interval between the treatment fractions. Conclusion: It was concluded that the model could be fitted to reproduce the experimental data well within its uncertainties. It was also demonstrated that the fitted model can be used to form hypotheses to be validated by further pre-clinical experiments. Advances in knowledge: The results of this work support the hypothesis that the synergetic action of combined radiotherapy and immunotherapy is favoured by using a hypofractionated radiation treatment regimen, given over a short time interval.
|
|
| 5. |
|
|
