Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy.
L-[methyl-11C]Methionine (11C-Met) is useful for estimating the therapeutic efficacy of particle radiotherapy at early stages of the treatment. Given the short half-life of 11C, the development of longer-lived 18F- and 123I-labeled probes that afford diagnostic information similar to 11C-Met, are be...
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doaj-537fd61a47a946f48a45913d69aa519a2020-11-24T20:41:27ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01122e017309610.1371/journal.pone.0173096Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy.Tomoya UeharaMariko WatanabeHiroyuki SuzukiYoshiya FurusawaYasushi AranoL-[methyl-11C]Methionine (11C-Met) is useful for estimating the therapeutic efficacy of particle radiotherapy at early stages of the treatment. Given the short half-life of 11C, the development of longer-lived 18F- and 123I-labeled probes that afford diagnostic information similar to 11C-Met, are being sought. Tumor uptake of 11C-Met is involved in many cellular functions such as amino acid transport System-L, protein synthesis, and transmethylation. Among these processes, since the energy-dependent intracellular functions involved with 11C-Met are more reflective of the radiotherapeutic effects, we evaluated the activity of the amino acid transport System-A as an another energy-dependent cellular function in order to estimate radiotherapeutic effects. In this study, using a carbon-ion beam as the radiation source, the activity of System-A was evaluated by a specific System-A substrate, alpha-[1-14C]-methyl-aminoisobutyric acid (14C-MeAIB). Cellular growth and the accumulation of 14C-MeAIB or 14C-Met were evaluated over time in vitro in cultured human salivary gland (HSG) tumor cells (3-Gy) or in vivo in murine xenografts of HSG tumors (6- or 25-Gy) before and after irradiation with the carbon-ion beam. Post 3-Gy irradiation, in vitro accumulation of 14C-Met and 14C-MeAIB decreased over a 5-day period. In xenografts of HSG tumors in mice, tumor re-growth was observed in vivo on day-10 after a 6-Gy irradiation dose, but no re-growth was detected after the 25-Gy irradiation dose. Consistent with the growth results, the in vivo tumor accumulation of 14C-MeAIB did not decrease after the 6-Gy irradiation dose, whereas a significant decrease was observed after the 25-Gy irradiation dose. These results indicate that the activity of energy dependent System-A transporter may reflect the therapeutic efficacy of carbon-ion radiotherapy and suggests that longer half-life radionuclide-labeled probes for System-A may also provide widely available probes to evaluate the effects of particle radiotherapy on tumors at early stage of the treatment.http://europepmc.org/articles/PMC5330493?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tomoya Uehara Mariko Watanabe Hiroyuki Suzuki Yoshiya Furusawa Yasushi Arano |
spellingShingle |
Tomoya Uehara Mariko Watanabe Hiroyuki Suzuki Yoshiya Furusawa Yasushi Arano Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. PLoS ONE |
author_facet |
Tomoya Uehara Mariko Watanabe Hiroyuki Suzuki Yoshiya Furusawa Yasushi Arano |
author_sort |
Tomoya Uehara |
title |
Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. |
title_short |
Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. |
title_full |
Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. |
title_fullStr |
Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. |
title_full_unstemmed |
Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy. |
title_sort |
amino acid transport system - a substrate predicts the therapeutic effects of particle radiotherapy. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2017-01-01 |
description |
L-[methyl-11C]Methionine (11C-Met) is useful for estimating the therapeutic efficacy of particle radiotherapy at early stages of the treatment. Given the short half-life of 11C, the development of longer-lived 18F- and 123I-labeled probes that afford diagnostic information similar to 11C-Met, are being sought. Tumor uptake of 11C-Met is involved in many cellular functions such as amino acid transport System-L, protein synthesis, and transmethylation. Among these processes, since the energy-dependent intracellular functions involved with 11C-Met are more reflective of the radiotherapeutic effects, we evaluated the activity of the amino acid transport System-A as an another energy-dependent cellular function in order to estimate radiotherapeutic effects. In this study, using a carbon-ion beam as the radiation source, the activity of System-A was evaluated by a specific System-A substrate, alpha-[1-14C]-methyl-aminoisobutyric acid (14C-MeAIB). Cellular growth and the accumulation of 14C-MeAIB or 14C-Met were evaluated over time in vitro in cultured human salivary gland (HSG) tumor cells (3-Gy) or in vivo in murine xenografts of HSG tumors (6- or 25-Gy) before and after irradiation with the carbon-ion beam. Post 3-Gy irradiation, in vitro accumulation of 14C-Met and 14C-MeAIB decreased over a 5-day period. In xenografts of HSG tumors in mice, tumor re-growth was observed in vivo on day-10 after a 6-Gy irradiation dose, but no re-growth was detected after the 25-Gy irradiation dose. Consistent with the growth results, the in vivo tumor accumulation of 14C-MeAIB did not decrease after the 6-Gy irradiation dose, whereas a significant decrease was observed after the 25-Gy irradiation dose. These results indicate that the activity of energy dependent System-A transporter may reflect the therapeutic efficacy of carbon-ion radiotherapy and suggests that longer half-life radionuclide-labeled probes for System-A may also provide widely available probes to evaluate the effects of particle radiotherapy on tumors at early stage of the treatment. |
url |
http://europepmc.org/articles/PMC5330493?pdf=render |
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