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Fu J, Yang Z, Melemenidis S, Viswanathan V, Dutt S, Manjappa R, Lau B, Soto LA, Ashraf MR, Skinner L, Yu SJ, Surucu M, Casey KM, Rankin EB, Graves E, Lu W, Loo BW, Gu X. Exploring Deep Learning for Estimating the Isoeffective Dose of FLASH Irradiation From Mouse Intestinal Histological Images. Int J Radiat Oncol Biol Phys 2024:S0360-3016(23)08306-2. [PMID: 38171387 DOI: 10.1016/j.ijrobp.2023.12.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 12/09/2023] [Accepted: 12/23/2023] [Indexed: 01/05/2024]
Abstract
PURPOSE Ultrahigh-dose-rate (FLASH) irradiation has been reported to reduce normal tissue damage compared with conventional dose rate (CONV) irradiation without compromising tumor control. This proof-of-concept study aims to develop a deep learning (DL) approach to quantify the FLASH isoeffective dose (dose of CONV that would be required to produce the same effect as the given physical FLASH dose) with postirradiation mouse intestinal histology images. METHODS AND MATERIALS Eighty-four healthy C57BL/6J female mice underwent 16 MeV electron CONV (0.12 Gy/s; n = 41) or FLASH (200 Gy/s; n = 43) single fraction whole abdominal irradiation. Physical dose ranged from 12 to 16 Gy for FLASH and 11 to 15 Gy for CONV in 1 Gy increments. Four days after irradiation, 9 jejunum cross-sections from each mouse were hematoxylin and eosin stained and digitized for histological analysis. CONV data set was randomly split into training (n = 33) and testing (n = 8) data sets. ResNet101-based DL models were retrained using the CONV training data set to estimate the dose based on histological features. The classical manual crypt counting (CC) approach was implemented for model comparison. Cross-section-wise mean squared error was computed to evaluate the dose estimation accuracy of both approaches. The validated DL model was applied to the FLASH data set to map the physical FLASH dose into the isoeffective dose. RESULTS The DL model achieved a cross-section-wise mean squared error of 0.20 Gy2 on the CONV testing data set compared with 0.40 Gy2 of the CC approach. Isoeffective doses estimated by the DL model for FLASH doses of 12, 13, 14, 15, and 16 Gy were 12.19 ± 0.46, 12.54 ± 0.37, 12.69 ± 0.26, 12.84 ± 0.26, and 13.03 ± 0.28 Gy, respectively. CONCLUSIONS Our proposed DL model achieved accurate CONV dose estimation. The DL model results indicate that in the physical dose range of 13 to 16 Gy, the biologic dose response of small intestinal tissue to FLASH irradiation is represented by a lower isoeffective dose compared with the physical dose. Our DL approach can be a tool for studying isoeffective doses of other radiation dose modifying interventions.
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Affiliation(s)
- Jie Fu
- Department of Radiation Oncology, University of Washington, Seattle, Washington; Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Zi Yang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Suparna Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Luis A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - M Ramish Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Shu-Jung Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Kerriann M Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California
| | - Erinn B Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Edward Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Weiguo Lu
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
| | - Xuejun Gu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
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Barghouth PG, Melemenidis S, Montay-Gruel P, Ollivier J, Viswanathan V, Jorge PG, Soto LA, Lau BC, Sadeghi C, Edlabadkar A, Zhang R, Ru N, Baulch JE, Manjappa R, Wang J, Le Bouteiller M, Surucu M, Yu A, Bush K, Skinner L, Maxim PG, Loo BW, Limoli CL, Vozenin MC, Frock RL. FLASH-RT does not affect chromosome translocations and junction structures beyond that of CONV-RT dose-rates. Radiother Oncol 2023; 188:109906. [PMID: 37690668 PMCID: PMC10591966 DOI: 10.1016/j.radonc.2023.109906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND AND PURPOSE The impact of radiotherapy (RT) at ultra high vs conventional dose rate (FLASH vs CONV) on the generation and repair of DNA double strand breaks (DSBs) is an important question that remains to be investigated. Here, we tested the hypothesis as to whether FLASH-RT generates decreased chromosomal translocations compared to CONV-RT. MATERIALS AND METHODS We used two FLASH validated electron beams and high-throughput rejoin and genome-wide translocation sequencing (HTGTS-JoinT-seq), employing S. aureus and S. pyogenes Cas9 "bait" DNA double strand breaks (DSBs) in HEK239T cells, to measure differences in bait-proximal repair and their genome-wide translocations to "prey" DSBs generated after various irradiation doses, dose rates and oxygen tensions (normoxic, 21% O2; physiological, 4% O2; hypoxic, 2% and 0.5% O2). Electron irradiation was delivered using a FLASH capable Varian Trilogy and the eRT6/Oriatron at CONV (0.08-0.13 Gy/s) and FLASH (1x102-5x106 Gy/s) dose rates. Related experiments using clonogenic survival and γH2AX foci in the 293T and the U87 glioblastoma lines were also performed to discern FLASH-RT vs CONV-RT DSB effects. RESULTS Normoxic and physioxic irradiation of HEK293T cells increased translocations at the cost of decreasing bait-proximal repair but were indistinguishable between CONV-RT and FLASH-RT. Although no apparent increase in chromosome translocations was observed with hypoxia-induced apoptosis, the combined decrease in oxygen tension with IR dose-rate modulation did not reveal significant differences in the level of translocations nor in their junction structures. Furthermore, RT dose rate modality on U87 cells did not change γH2AX foci numbers at 1- and 24-hours post-irradiation nor did this affect 293T clonogenic survival. CONCLUSION Irrespective of oxygen tension, FLASH-RT produces translocations and junction structures at levels and proportions that are indistinguishable from CONV-RT.
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Affiliation(s)
- Paul G Barghouth
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Pierre Montay-Gruel
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland; Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Jonathan Ollivier
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrik G Jorge
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Luis A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Brianna C Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cheyenne Sadeghi
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anushka Edlabadkar
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Richard Zhang
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinghui Wang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marie Le Bouteiller
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amy Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karl Bush
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peter G Maxim
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Richard L Frock
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Jiang H, Fu J, Melemenidis S, Viswanathan V, Dutt S, Lau B, Soto LA, Manjappa R, Skinner L, Yu SJ, Surucu M, Graves EE, Casey K, Rankin E, Lu W, Loo BW, Gu X. An Online AI-Powered Interactive Histological Image Annotation Platform for Analyzing Intestinal Regenerating Crypts in Post-Irradiated Mice. Int J Radiat Oncol Biol Phys 2023; 117:e676. [PMID: 37785993 DOI: 10.1016/j.ijrobp.2023.06.2130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) The goal of this project is to build an online AI-powered interactive annotation platform to accurately and efficiently annotate intestinal regenerating crypts in histological images of mice after abdominal irradiation. MATERIALS/METHODS The proposed platform is developed by the seamless integration of a front-end web client and a back-end server. Such client/server design allows the users to access the platform without software installation on local computers. Our front-end client is developed with SvelteJS + WebGL technology stack, allowing access from any common web browsers and enabling user interaction, such as image importing/visualization, interactive crypt annotating, and annotation saving/deleting. The back-end server is responsible for executing the tasks requested from the web client, for instance, image pre-processing, AI-based crypts automatic identification, and database management. The image preprocessing is designed to extract a single cross section image using morphological operations because multiple hematoxylin and eosin (H&E) stained jejunum cross sections from post-irradiated mice are scanned within one slide. The auto-crypt identification is powered by a trained and validated AI engine U-Net, classifying image grid tiles into two groups with and without regenerating crypts. The database is implemented with the self-contained SQLite to support recording and indexing the annotated grid tiles with regenerating crypts. The workflow for crypt analysis on this interactive platform has 5 steps: 1) manually import a whole H&E slide image; 2) auto-preprocess the slide by extracting single cross-section images; 3) auto-identify regenerating crypts with an AI engine; 4) interactively annotate (add, delete, modify) auto-identified crypt markers; 5) save and/or output the annotation to the database or the local drive. RESULTS The performance of the developed interactive crypt analysis platform was evaluated in aspects of accuracy and efficiency. The AI-powered crypt auto-identification accuracy was assessed by computing the mean absolute error (MAE) on crypt number per cross section between manual and auto annotation using a testing dataset containing 80 cross sections. It achieved an MAE of 3.5±4.8 crypts per cross section, and 81.25% of the cross sections have no more than 5 crypts difference. The efficiency was assessed under two conditions with the server on the cloud and a local computer. It took about 2-3 minutes to finish the entire workflow on the cloud, while 1-2 minutes on the local by saving ∼1 minute on image uploading. CONCLUSION The developed web client/server platform enables online automatic identification and interactive annotation of mice crypts in minutes. It is a convenient tool that allows accurate and efficient crypt analysis and can be extended for other histologic image analyses.
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Affiliation(s)
| | - J Fu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - V Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - B Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - R Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S J Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - M Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - E E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - K Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, CA
| | - E Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - W Lu
- University of Texas Southwestern Department of Radiation Oncology, Dallas, TX
| | - B W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - X Gu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
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Fu J, Jiang H, Melemenidis S, Viswanathan V, Dutt S, Lau B, Soto LA, Manjappa R, Skinner L, Yu SJ, Surucu M, Graves EE, Casey K, Rankin E, Lu W, Loo BW, Gu X. Deep Learning-Based Pipeline for Automatic Identification of Intestinal Regenerating Crypts in Mouse Histological Images. Int J Radiat Oncol Biol Phys 2023; 117:S117-S118. [PMID: 37784305 DOI: 10.1016/j.ijrobp.2023.06.451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) A classical approach for evaluating normal tissue radiation response is to count the number of intestinal regenerating crypts in mouse histological images acquired after abdominal radiation. However, manual counting is time-consuming and subject to inter-observer variations. The goal of this study is to build a deep learning-based pipeline for automatically identifying intestinal regenerating crypts to facilitate high-throughput studies. MATERIALS/METHODS Sixty-six healthy C57BL/6 female mice underwent 16 MeV whole abdominal electron irradiation. The small bowel was collected from each mouse 4 days post-irradiation, and 9 jejunal cross-sections from each were processed together in a single slide. The slides were stained with hematoxylin and eosin (H&E) and subsequently scanned (x20), providing one electronic histological image per mouse. Regenerating crypts, consisting of more than 10 basophilic crypt epithelial cells, were manually identified using point annotations in histological images. The pipeline was built to take the input of the image containing 9 cross sections and automatically identify the regenerating crypts on each cross section. It mainly consists of two components, cross section segmentation using intensity thresholding and morphological operations and crypt identification using a UNet. The dataset was randomly split into 46, 10, and 10 slide images for UNet training, validation, and testing. Each slide image was split into grid tiles with a voxel size of 200 × 200, and 40 × 40 square masks were placed with centers at manual point annotations on tiles with regenerating crypts. 5203/5198 tiles (w/wo crypt mask) were extracted to train UNet by minimizing dice loss. The mask probability map generated by the UNet was post-processed to identify the crypt position. Postprocessing hyperparameters were tuned using the validation dataset. The model accuracy was evaluated using the testing dataset by computing the mean absolute error (MAE) of the crypt number averaged across all cross sections. RESULTS The number of regenerating crypts on testing cross sections ranges from 1 to 63. The testing cross-section-wise MAE achieved by the platform is 3.5±4.8 crypts. 81.25% of testing cross sections have absolute number differences less than or equal to 5 crypts. CONCLUSION Our established deep learning-based pipeline can accurately count the number of regenerating crypts in mouse intestinal histological images. We have integrated it into an online platform that enables automatic crypt identification and allows users to interactively modify auto-identified crypt annotations. The acquired annotations from the platform will be used to finetune the deep learning model to achieve better identification performance.
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Affiliation(s)
- J Fu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | | | - S Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - V Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - B Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - R Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S J Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - M Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - E E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - K Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, CA
| | - E Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - W Lu
- University of Texas Southwestern Department of Radiation Oncology, Dallas, TX
| | - B W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - X Gu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
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Yang Z, Fu J, Melemenidis S, Viswanathan V, Dutt S, Lau B, Soto LA, Manjappa R, Skinner L, Yu SJ, Surucu M, Casey K, Rankin E, Lu W, Jr BWL, Gu X. Equivalent Dose Estimation in FLASH Irradiation with a Deep Learning Approach. Int J Radiat Oncol Biol Phys 2023; 117:e272. [PMID: 37785029 DOI: 10.1016/j.ijrobp.2023.06.1241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Ultra-high dose rate (FLASH) irradiation has been reported to provide decreased normal tissue toxicity without compromising tumor control compared with conventional (CONV) irradiation. However, a comprehensive understanding of the FLASH biological effect requires precise quantification of radiobiology. The study is to explore whether deep learning (DL) can tackle the task. As a proof of concept, we investigate a DL model for estimating FLASH dose to its equivalent CONV dose. MATERIALS/METHODS Healthy C57Bl/6 female mice underwent FLASH (200Gy/s; n = 43) or CONV (0.12Gy/s; n = 41) whole abdominal irradiation using ∼16 MeV electron beams with a dose escalation scheme of 5 groups (n = 8 or 9) at 1Gy increments: 12-16Gy FLASH, 11-15Gy CONV. 4 days post-irradiation, 9 jejunum cross-sections per mouse were H&E stained for histological analysis. Each cross-section image was processed to remove lumen background and oversampled into multiple large-scale and small-scale patches along jejunal circumference. In CONV dataset, we randomly selected the data of 32 mice (80%) for model training and the rest (20%) for model validation. A ResNet101-based DL model, pre-trained with an unsupervised contrastive learning scheme, was retrained with only CONV training set to estimate corresponding CONV dose. For comparison, a crypt counting (CC) approach was implemented by manually counting the number of regenerating crypts on each cross-section image. An exponential function of dose vs crypt number was fitted with the CONV training set and used for dose estimation on the testing set. Mean squared error (MSE) was used to assess the accuracy of DL and CC approaches in estimating dose levels in CONV irradiation. The validated DL model was applied to the FLASH set to project FLASH dose into corresponding CONV dose that results in equivalent biological response. RESULTS The CONV dose estimated by DL and CC approaches and DL-estimated FLASH equivalent dose were summarized in Table 1. The DL model achieved an MSE of 0.21 Gy2 on CONV testing set compared with 0.32 Gy2 of the CC approach. FLASH equivalent dose estimated by DL model for 12, 13, 14, 15 and 16Gy were 12.16±0.40, 12.53±0.32, 12.72±0.24, 12.85±0.20 and 13.04±0.27 Sv, respectively. CONCLUSION Our proposed DL model can accurately estimate the CONV dose based on histological images. The DL predictions of FLASH dataset demonstrate that FLASH may reduce normal tissue toxicity with a lower equivalent dose, especially at high irradiated dose levels. Our study indicates that deep learning can be potentially used to assess the equivalent dose of FLASH irradiation to normal tissue.
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Affiliation(s)
- Z Yang
- Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX
| | - J Fu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - V Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - B Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - R Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S J Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - M Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - K Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, CA
| | - E Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - W Lu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX
| | - B W Loo Jr
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - X Gu
- Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX; Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
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Ashraf MR, Melemenidis S, Liu K, Velasquez BD, Manjappa R, Soto LA, Dutt S, Skinner L, Yu SJ, Surucu M, Graves EE, Maxim PG, Schueler E, Loo BW. Anatomically Realistic 3D Printed Mouse Phantom for Multi-Institutional Benchmarking of FLASH and CONV Irradiation. Int J Radiat Oncol Biol Phys 2023; 117:e697. [PMID: 37786044 DOI: 10.1016/j.ijrobp.2023.06.2178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) It is reported that about US$28B/year is spent on pre-clinical studies that are not reproducible. FLASH studies may suffer from the same reproducibility crisis due to the non-standard nature of the FLASH beamlines and the lack of dosimeters that can function at ultra-high dose-rates. There have been reports of different outcomes with regard to the FLASH effect across different institutions, even though similar beamlines, temporal structure, and nominal dose levels were used. This brings up the question of the accuracy of dosimetry under FLASH conditions for a fair comparison between FLASH and CONV. To answer this question, we develop and characterize an anatomically realistic 3D-printed mouse phantom to be used in a multi-institutional dosimetric benchmarking effort. MATERIALS/METHODS Mesh files for bony anatomy, lungs, and soft tissue derived from a CT scan of a mouse were converted to an editable 3D model. The 3D model was cut along the coronal plane and modified to allow the inclusion of radiographic film. A multi-material approach was employed to print the phantom. A dual-nozzle 3D printer was used, where one of the nozzles used Acrylonitrile butadiene styrene (ABS) to mimic soft tissue and the other nozzle used Polyactic acid (PLA) to mimic bone density. The two materials were used together in a single print. Lungs were approximated by lightweight PLA and were printed separately and inserted into corresponding cavities in the phantom. Hounsfield Units (HU) and print-to-print stability were verified. Radiographic films were laser cut for different anatomical sites. Two institutes took part in this study with data pending from 3 more institutions. The institutes were instructed to deliver 10 Gy to the plane of the film for the whole abdomen, whole lung, and brain irradiations. 2D dose maps were compared between FLASH and CONV, and the deviation from the prescribed dose was also measured. RESULTS The 3D-printed soft tissue, bone, and lung densities were measured to be ∼ 1.01 g/cc, 1.22 g/cc, and 0.44 g/cc, respectively. For soft tissue and bone, the Hounsfield unit (HU) difference from one print to another was < 10 HU. The greatest variation was within the lungs (54 HU), but this had a minimal effect on the dose distribution (<1%). For the two institutions that completed the survey, the maximum average difference between FLASH and CONV for all irradiations was 0.75 Gy (7.48%). The maximum average difference from the prescribed dose for all irradiations was 0.7 Gy (7.20%) across both institutions. The largest discrepancy was generally observed to be for lung irradiation, indicating that lack of treatment planning systems limits our ability to prescribe accurately in areas of inhomogeneities. CONCLUSION A 3D printed anatomically realistic mouse phantom was developed, characterized, and used in a multi-institutional dosimetric benchmarking effort. Such a study is paramount for the clinical translation of FLASH as it facilitates reduced variability from one institution to another.
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Affiliation(s)
- M R Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, CA
| | - S Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - K Liu
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - B D Velasquez
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | | | - L A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S J Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - M Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - E E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - P G Maxim
- University of California, Irvine, Irvine, CA
| | | | - B W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
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7
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Melemenidis S, Viswanathan V, Dutt S, Manjappa R, Ashraf MR, Soto LA, Skinner L, Yu SJ, Surucu M, Graves EE, Loo B, Dirbas FM. Comparison of Tumor Control between FLASH and CONV in an Orthotopic Breast Cancer Model. Int J Radiat Oncol Biol Phys 2023; 117:e251-e252. [PMID: 37784977 DOI: 10.1016/j.ijrobp.2023.06.1194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Post-lumpectomy radiotherapy (RT) reduces in-breast tumor recurrence by eradicating residual, occult breast cancer (BC) that may be in the mm size scale. The ability of FLASH-RT to eradicate BC relative to conventional dose rate (CONV) RT is unknown. ∼ 20Gy RT is currently used clinically for single-fraction breast IORT. Determine the effectiveness of FLASH compared to CONV in eradicating small tumors in an orthotopic, syngeneic model of BC using single-fraction 20 or 30Gy RT. MATERIALS/METHODS Radiation sensitive, mammary tumor cell line Py117 from the transgenic model of the mouse mammary tumor virus promoter driving the polyoma middle T antigen (MMTV- PyMT) efficiently forms non-metastatic, orthotopic tumors in C57BL/6 mice. 106 Py117 cells were injected orthotopically into the left 4th mammary fat pad of C57Bl/6J mice. Radiotherapy was performed with a custom jig that allows for fixed positioning of the target volume (2x2cm radiation field) with 5mm of margin into surrounding tissue. Tumors were irradiated at ∼30mm3 volume or, for comparison, at a range of greater volumes (200-800mm3) with 20 or 30Gy FLASH or CONV with 16-17 MeV electrons. RESULTS Small 30mm3 tumors regressed until ∼ day 15 after 20Gy single fraction RT then regrew for both FLASH and CONV. 30mm3 tumors were eradicated with both FLASH and CONV at 30Gy with no regrowth up to day 35 post-RT. Larger tumors irradiated with 30Gy regressed until ∼ day 12 post-RT then regrew for both FLASH and CONV. There was no significant difference in growth delay or tumor eradication between FLASH and CONV in any cohort. CONCLUSION FLASH was as effective as CONV in controlling growth and eradicating murine BC. Based on other preclinical studies, single-fraction doses between 20 and 30Gy, as well as hypofractioned RT schedules, may identify FLASH doses that achieve comparable tumor control with less toxicity than CONV. Such findings would encourage clinical trials of FLASH in human BC.
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Affiliation(s)
- S Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - V Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - R Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA; Stanford University, Stanford
| | - M R Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, CA
| | - L A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - L Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - S J Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - M Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - E E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
| | - B Loo
- TibaRay, Inc., STANFORD, CA
| | - F M Dirbas
- Stanford University, Stanford, CA, United States
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8
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Barghouth PG, Melemenidis S, Montay-Gruel P, Ollivier J, Viswanathan V, Jorge PG, Soto LA, Lau BC, Sadeghi C, Edlabadkar A, Manjappa R, Wang J, Le Bouteiller M, Surucu M, Yu A, Bush K, Skinner L, Maxim PG, Loo BW, Limoli CL, Vozenin MC, Frock RL. FLASH-RT does not affect chromosome translocations and junction structures beyond that of CONV-RT dose-rates. bioRxiv 2023:2023.03.27.534408. [PMID: 37034651 PMCID: PMC10081175 DOI: 10.1101/2023.03.27.534408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The molecular and cellular mechanisms driving the enhanced therapeutic ratio of ultra-high dose-rate radiotherapy (FLASH-RT) over slower conventional (CONV-RT) radiotherapy dose-rate remain to be elucidated. However, attenuated DNA damage and transient oxygen depletion are among several proposed models. Here, we tested whether FLASH-RT under physioxic (4% O 2 ) and hypoxic conditions (≤2% O 2 ) reduces genome-wide translocations relative to CONV-RT and whether any differences identified revert under normoxic (21% O 2 ) conditions. We employed high-throughput rejoin and genome-wide translocation sequencing ( HTGTS-JoinT-seq ), using S. aureus and S. pyogenes Cas9 "bait" DNA double strand breaks (DSBs), to measure differences in bait-proximal repair and their genome-wide translocations to "prey" DSBs generated by electron beam CONV-RT (0.08-0.13Gy/s) and FLASH-RT (1×10 2 -5×10 6 Gy/s), under varying ionizing radiation (IR) doses and oxygen tensions. Normoxic and physioxic irradiation of HEK293T cells increased translocations at the cost of decreasing bait-proximal repair but were indistinguishable between CONV-RT and FLASH-RT. Although no apparent increase in chromosome translocations was observed with hypoxia-induced apoptosis, the combined decrease in oxygen tension with IR dose-rate modulation did not reveal significant differences in the level of translocations nor in their junction structures. Thus, Irrespective of oxygen tension, FLASH-RT produces translocations and junction structures at levels and proportions that are indistinguishable from CONV-RT.
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Affiliation(s)
- Paul G. Barghouth
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Pierre Montay-Gruel
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Jonathan Ollivier
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrik G. Jorge
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Luis A. Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Brianna C. Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cheyenne Sadeghi
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anushka Edlabadkar
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinghui Wang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marie Le Bouteiller
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amy Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karl Bush
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peter G. Maxim
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Billy W. Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland
| | - Richard L. Frock
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
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9
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Soto LA, Casey KM, Wang J, Blaney A, Manjappa R, Breitkreutz D, Skinner L, Dutt S, Ko RB, Bush K, Yu AS, Melemenidis S, Strober S, Englemann E, Maxim PG, Graves EE, Loo BW. FLASH Irradiation Results in Reduced Severe Skin Toxicity Compared to Conventional-Dose-Rate Irradiation. Radiat Res 2021; 194:618-624. [PMID: 32853385 DOI: 10.1667/rade-20-00090] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023]
Abstract
Radiation therapy, along with surgery and chemotherapy, is one of the main treatments for cancer. While radiotherapy is highly effective in the treatment of localized tumors, its main limitation is its toxicity to normal tissue. Previous preclinical studies have reported that ultra-high dose-rate (FLASH) irradiation results in reduced toxicity to normal tissues while controlling tumor growth to a similar extent relative to conventional-dose-rate (CONV) irradiation. To our knowledge this is the first report of a dose-response study in mice comparing the effect of FLASH irradiation vs. CONV irradiation on skin toxicity. We found that FLASH irradiation results in both a lower incidence and lower severity of skin ulceration than CONV irradiation 8 weeks after single-fraction hemithoracic irradiation at high doses (30 and 40 Gy). Survival was also higher after FLASH hemithoracic irradiation (median survival >180 days at doses of 30 and 40 Gy) compared to CONV irradiation (median survival 100 and 52 days at 30 and 40 Gy, respectively). No ulceration was observed at doses 20 Gy or below in either FLASH or CONV. These results suggest a shifting of the dose-response curve for radiation-induced skin ulceration to the right for FLASH, compared to CONV irradiation, suggesting the potential for an enhanced therapeutic index for radiation therapy of cancer.
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Affiliation(s)
- Luis A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305.,Cancer Biology Program, Stanford University School of Medicine, Stanford, California 94305
| | - Kerriann M Casey
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California 94305
| | - Jinghui Wang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Alexandra Blaney
- Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California 94305
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Dylan Breitkreutz
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Suparna Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305.,Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, California 94305
| | - Ryan B Ko
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Karl Bush
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Amy S Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305
| | - Samuel Strober
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, California 94305.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California 94305
| | - Edgar Englemann
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, California 94305.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California 94305.,Department of Pathology, Stanford University School of Medicine, Stanford, California 94305
| | - Peter G Maxim
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California 94305.,Department of Pathology, Stanford University School of Medicine, Stanford, California 94305
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California 94305.,Department of Pathology, Stanford University School of Medicine, Stanford, California 94305
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10
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Ko RB, Soto LA, von Eyben R, Melemenidis S, Rankin EB, Maxim PG, Graves EE, Loo BW. Evaluating the Reproducibility of Mouse Anatomy under Rotation in a Custom Immobilization Device for Conformal FLASH Radiotherapy. Radiat Res 2021; 194:600-606. [PMID: 32857849 DOI: 10.1667/rade-20-00095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/18/2020] [Indexed: 11/03/2022]
Abstract
The observation of an enhanced therapeutic index for FLASH radiotherapy in mice has created interest in practical laboratory-based FLASH irradiators. To date, systems capable of 3D conformal FLASH irradiation in mice have been lacking. We are developing such a system, incorporating a high-current linear accelerator to produce a collimated X-ray beam in a stationary beamline design, rotating the mouse about a longitudinal axis to achieve conformal irradiation from multiple beam directions. The purpose of this work was to evaluate the reproducibility of mouse anatomy under rotation at speeds compatible with conformal FLASH delivery. Three short-hair mice and two hairless mice were immobilized under anesthesia in body weight-specific contoured plastic molds, and subjected to three rotational (up to 3 revolutions/s) and two non-rotational movement interventions. MicroCT images were acquired before and after each intervention. The displacements of 11 anatomic landmarks were measured on the image pairs. The displacement of the anatomical landmarks with any of the interventions was 0.5 mm or less for 92.4% of measurements, with a single measurement out of 275 (11 landmarks × 5 interventions × 5 mice) reaching 1 mm. There was no significant difference in the displacements associated with rotation compared to those associated with moving the immobilized mouse in and out of a scanner or with leaving the mouse in place for 5 min with no motion. There were no significant differences in displacements between mice with or without hair, although the analysis is limited by small numbers, or between different anatomic landmarks. These results show that anatomic reproducibility under rotation speed corresponding to FLASH irradiation times appears to be compatible with conformal/stereotactic irradiation in mice.
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Affiliation(s)
- Ryan B Ko
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Luis A Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Rie von Eyben
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Erinn B Rankin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.,Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, California.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
| | - Peter G Maxim
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.,Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
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11
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Zheng X, Cui L, Chen M, Soto LA, Graves EE, Rao J. A Near-Infrared Phosphorescent Nanoprobe Enables Quantitative, Longitudinal Imaging of Tumor Hypoxia Dynamics during Radiotherapy. Cancer Res 2019; 79:4787-4797. [PMID: 31311808 DOI: 10.1158/0008-5472.can-19-0530] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/21/2019] [Accepted: 07/11/2019] [Indexed: 12/17/2022]
Abstract
Hypoxia plays a key role in tumor resistance to radiotherapy. It is important to study hypoxia dynamics during radiotherapy to improve treatment planning and prognosis. Here, we describe a luminescent nanoprobe, composed of a fluorescent semiconducting polymer and palladium complex, for quantitative longitudinal imaging of tumor hypoxia dynamics during radiotherapy. The nanoprobe was designed to provide high sensitivity and reversible response for the subtle change in hypoxia over a narrow range (0-30 mmHg O2), which spans the oxygen range where tumors have limited radiosensitivity. Following intravenous administration, the nanoprobe efficiently accumulated in and distributed across the tumor, including the hypoxic region. The ratio between emissions at 700 and 800 nm provided quantitative mapping of hypoxia across the entire tumor. The nanoprobe was used to image tumor hypoxia dynamics over 7 days during fractionated radiotherapy and revealed that high fractional dose (10 Gy) was more effective in improving tumor reoxygenation than low dose (2 Gy), and the effect tended to persist longer in smaller or more radiosensitive tumors. Our results also indicated the importance of the reoxygenation efficiency of the first fraction in the prediction of the radiation treatment outcome. In summary, this work has established a new nanoprobe for highly sensitive, quantitative, and longitudinal imaging of tumor hypoxia dynamics following radiotherapy, and demonstrated its value for assessing the efficacy of radiotherapy and radiation treatment planning. SIGNIFICANCE: This study presents a novel nanoagent for the visualization and quantification of tumor hypoxia.
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Affiliation(s)
- Xianchuang Zheng
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Liyang Cui
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Min Chen
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Luis A Soto
- Department of Radiation Oncology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Edward E Graves
- Department of Radiation Oncology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Jianghong Rao
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California.
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12
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Escobar-Chicho M, Soto LA, Vanegas-Pérez C, Estradas-Romero A. Heavy Metal Bioaccumulation in the Anemone Paraphelliactis pabista Dunn, 1982 (Actiniaria: Hormathiidae) from the Hydrothermal System of Guaymas Basin, Gulf of California. Bull Environ Contam Toxicol 2019; 102:486-491. [PMID: 30953087 DOI: 10.1007/s00128-019-02588-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 03/06/2019] [Indexed: 06/09/2023]
Abstract
A single specimen of the anemone Paraphelliactis pabista was recovered from the Southern Trough of Guaymas Basin during the deep-sea expedition Extreme 2008 conducted onboard the R/V Atlantis/DSRV-2 ALVIN. We studied the bioaccumulation capacity of heavy metals in various tissues of the anemone (oral disk-columella-pedal disk), and retention or adhesion of mineral particles in the epidermis, mesoglea, and gastrodermis. The digested tissues were analyzed for As, Ba, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, Sb, Sr, Ti, V, and Zn by inductively coupled plasma mass spectrometry. This analysis revealed the capacity of P. pabista for accumulating heavy metals. The predominant mineral particles identified in tissue samples was barite followed by Fe, aluminum-silicates, Sr, and with less presence Cr, Ti, and pyrite. Of the three body compartments analyzed of this anemone, the oral and pedal disks show a greater capacity of bioaccumulation of heavy metals than the columella.
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Affiliation(s)
- M Escobar-Chicho
- Instituto de Ciencias del Mar y Limnología, Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - L A Soto
- Instituto de Ciencias del Mar y Limnología, Ciudad Universitaria, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Coyoacán, 04510, Mexico City, Mexico.
| | - C Vanegas-Pérez
- Facultad de Ciencias, Ciudad Universitaria, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Coyoacán, 04510, Mexico City, Mexico
| | - A Estradas-Romero
- Facultad de Ciencias, Ciudad Universitaria, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Coyoacán, 04510, Mexico City, Mexico
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13
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Zubillaga A, Soto LA, Salcedo DL, Botello AV. Presence of Oil Mineral Aggregates (OMAs) in Surface Sediments from Mexico's Exclusive Economic Zone, NW Gulf of Mexico. Bull Environ Contam Toxicol 2018; 101:173-177. [PMID: 29995168 DOI: 10.1007/s00128-018-2396-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 07/06/2018] [Indexed: 06/08/2023]
Abstract
We assessed the presence and distribution of oil mineral aggregates (OMAs) in surficial sediments of Mexican waters in the NW Gulf of Mexico, their potential sources and their correlation with polycyclic aromatic hydrocarbons (PAH). In summer of 2010, OMAs were detected in three shallow sites. In winter of 2011, OMAs were observed in ten sites, two of them in the northernmost area at > 1500 m depth. These particles were possibly advected from the north Gulf and Mississippi area following the deep-water currents of the zone. The OMAs from shallower sites may reflect local pollution sources. PAHs displayed low concentrations in both surveys (from 0.01 to 0.7 µg g-1 in summer, and from 0.01 to 0.51 µg g-1 in winter), and showed rather a local origin. The expansion of the oil and port industry in the region is accountable for most of the OMAs detected.
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Affiliation(s)
- Alfredo Zubillaga
- Facultad de Ciencias, Lic. Ciencias de la Tierra, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis A Soto
- Instituto de Ciencias del Mar y Limnología, Ciudad Universitaria, Circuito Exterior s/n, Coyoacán, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Diana L Salcedo
- Instituto de Ciencias del Mar y Limnología, Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
| | - Alfonso V Botello
- Instituto de Ciencias del Mar y Limnología, Ciudad Universitaria, Circuito Exterior s/n, Coyoacán, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
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14
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Rafat M, Aguilera TA, Vilalta M, Bronsart LL, Soto LA, von Eyben R, Golla MA, Ahrari Y, Melemenidis S, Afghahi A, Jenkins MJ, Kurian AW, Horst KC, Giaccia AJ, Graves EE. Macrophages Promote Circulating Tumor Cell-Mediated Local Recurrence following Radiotherapy in Immunosuppressed Patients. Cancer Res 2018; 78:4241-4252. [PMID: 29880480 PMCID: PMC6072588 DOI: 10.1158/0008-5472.can-17-3623] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/09/2018] [Accepted: 05/25/2018] [Indexed: 01/07/2023]
Abstract
Although radiotherapy (RT) decreases the incidence of locoregional recurrence in breast cancer, patients with triple-negative breast cancer (TNBC) have increased risk of local recurrence following breast-conserving therapy. The relationship between RT and local recurrence is unknown. Here, we tested the hypothesis that recurrence in some instances is due to the attraction of circulating tumor cells to irradiated tissues. To evaluate the effect of absolute lymphocyte count on local recurrence after RT in patients with TNBC, we analyzed radiation effects on tumor and immune cell recruitment to tissues in an orthotopic breast cancer model. Recurrent patients exhibited a prolonged low absolute lymphocyte count when compared with nonrecurrent patients following RT. Recruitment of tumor cells to irradiated normal tissues was enhanced in the absence of CD8+ T cells. Macrophages (CD11b+F480+) preceded tumor cell infiltration and were recruited to tissues following RT. Tumor cell recruitment was mitigated by inhibiting macrophage infiltration using maraviroc, an FDA-approved CCR5 receptor antagonist. Our work poses the intriguing possibility that excessive macrophage infiltration in the absence of lymphocytes promotes local recurrence after RT. This combination thus defines a high-risk group of patients with TNBC.Significance: This study establishes the importance of macrophages in driving tumor cell recruitment to sites of local radiation therapy and suggests that this mechanism contributes to local recurrence in women with TNBC that are also immunosuppressed.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/15/4241/F1.large.jpg Cancer Res; 78(15); 4241-52. ©2018 AACR.
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Affiliation(s)
- Marjan Rafat
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Todd A Aguilera
- Department of Radiation Oncology, Harold C. Simmons Comprehensive Cancer Center, U.T. Southwestern Medical Center, Dallas, Texas
| | - Marta Vilalta
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Laura L Bronsart
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Luis A Soto
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Rie von Eyben
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Meghana A Golla
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Yasaman Ahrari
- Department of Radiation Oncology, Stanford University, Stanford, California
| | | | - Anosheh Afghahi
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Melissa J Jenkins
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Allison W Kurian
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Kathleen C Horst
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Amato J Giaccia
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University, Stanford, California.
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15
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Raz-Guzmán A, Soto LA. Updated checklist and zoogeographic remarks of benthic amphipods (Crustacea: Peracarida: Amphipoda) of two coastal lagoons in the western Gulf of Mexico. REV MEX BIODIVERS 2017. [DOI: 10.1016/j.rmb.2017.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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16
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Goffredi SK, Johnson S, Tunnicliffe V, Caress D, Clague D, Escobar E, Lundsten L, Paduan JB, Rouse G, Salcedo DL, Soto LA, Spelz-Madero R, Zierenberg R, Vrijenhoek R. Hydrothermal vent fields discovered in the southern Gulf of California clarify role of habitat in augmenting regional diversity. Proc Biol Sci 2017; 284:20170817. [PMID: 28724734 PMCID: PMC5543219 DOI: 10.1098/rspb.2017.0817] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/16/2017] [Indexed: 11/12/2022] Open
Abstract
Hydrothermal vent communities are distributed along mid-ocean spreading ridges as isolated patches. While distance is a key factor influencing connectivity among sites, habitat characteristics are also critical. The Pescadero Basin (PB) and Alarcón Rise (AR) vent fields, recently discovered in the southern Gulf of California, are bounded by previously known vent localities (e.g. Guaymas Basin and 21° N East Pacific Rise); yet, the newly discovered vents differ markedly in substrata and vent fluid attributes. Out of 116 macrofaunal species observed or collected, only three species are shared among all four vent fields, while 73 occur at only one locality. Foundation species at basalt-hosted sulfide chimneys on the AR differ from the functional equivalents inhabiting sediment-hosted carbonate chimneys in the PB, only 75 km away. The dominant species of symbiont-hosting tubeworms and clams, and peripheral suspension-feeding taxa, differ between the sites. Notably, the PB vents host a limited and specialized fauna in which 17 of 26 species are unknown at other regional vents and many are new species. Rare sightings and captured larvae of the 'missing' species revealed that dispersal limitation is not responsible for differences in community composition at the neighbouring vent localities. Instead, larval recruitment-limiting habitat suitability probably favours species differentially. As scenarios develop to design conservation strategies around mining of seafloor sulfide deposits, these results illustrate that models encompassing habitat characteristics are needed to predict metacommunity structure.
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Affiliation(s)
- Shana K Goffredi
- Department of Biology, Occidental College, Los Angeles, CA, USA
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Shannon Johnson
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Verena Tunnicliffe
- School of Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - David Caress
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - David Clague
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Elva Escobar
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Lonny Lundsten
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | | | - Greg Rouse
- Scripps Institution of Oceanography, La Jolla, CA, USA
| | - Diana L Salcedo
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis A Soto
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ronald Spelz-Madero
- Department of Geology, Universidad Autónoma de Baja California, Mexico City, Mexico
| | - Robert Zierenberg
- Earth and Planetary Sciences, University of California, Davis, Davis, CA, USA
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Abstract
The Joint Commission provides accreditation standards for staging hospital waste, but there are no federal lifting safety standards for linen bags. We evaluated hospital laundry bag lifting using the Revised National Institute for Occupational Safety and Health (NIOSH) Lifting Equation. We hypothesized that the permitted 32-gallon linen container capacity might allow filling to weights above our calculated Recommended Weight Limit (RWL) for some lifting positions and contents. We found that 30- and 40-gallon bags filled with loose dry linen had predicted weights within estimated RWLs only for lifts close to the body. Thirty- and 40-gallon bags filled more than halfway with dry compact linen had predicted weights above estimated RWLs for all lifting positions. Thirty- and 40-gallon bags filled with wet compact linen exceeded estimated RWLs for all positions when less than one-quarter full. Bag volume and filling controls may be considered to ensure linen bags are not excessively heavy.
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Affiliation(s)
- Erin Teeple
- 1 Department of Work Environment, University of Massachusetts, Lowell, MA, USA.,2 Liberty Mutual Research Institute for Safety, Hopkinton, MA, USA
| | - Jack T Dennerlein
- 3 Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,4 Department of Physical Therapy, Movement and Rehabilitation Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Dean Hashimoto
- 3 Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,5 Harvard Medical School, Boston, MA, USA.,6 Boston College Law School, Newton, MA, USA
| | | | - Elena Losina
- 5 Harvard Medical School, Boston, MA, USA.,7 Department of Orthopedic Surgery, Orthopaedic and Arthritis Center for Outcomes Research, Brigham and Women's Hospital, Boston, MA, USA.,8 Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.,9 Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Jeffrey N Katz
- 3 Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,5 Harvard Medical School, Boston, MA, USA.,7 Department of Orthopedic Surgery, Orthopaedic and Arthritis Center for Outcomes Research, Brigham and Women's Hospital, Boston, MA, USA.,8 Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.,10 Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA
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Salcedo DL, Soto LA, Estradas-Romero A, Botello AV. Interannual variability of soft-bottom macrobenthic communities of the NW Gulf of Mexico in relationship to the Deepwater Horizon oil spill. Mar Pollut Bull 2017; 114:987-994. [PMID: 27876372 DOI: 10.1016/j.marpolbul.2016.11.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 08/21/2016] [Accepted: 11/14/2016] [Indexed: 06/06/2023]
Abstract
A 3-year research program was undertaken to assess potential environmental disturbance caused by the Deepwater Horizon oil spill to the soft-bottom macrobenthic communities within Mexican waters of the northwestern Gulf of Mexico. Community properties and temporal/spatial variability were analyzed besides toxicant parameters such as hydrocarbons and trace-metals. Overall infaunal density increased, taxa proportion changed, and small-size opportunistic organisms prevailed throughout the study. Annual abundance-biomass comparison (ABC) curves revealed progressive stress scenarios from moderate to severe. Concentrations of vanadium, nickel, cobalt, PAHs and AHs increased gradually over time. However, low correlations between benthic density and biogeochemical variables were determined. Initially, sedimentary properties were the main drivers of benthic community structure; subsequently, nickel, vanadium and PAHs, indicative of anthropogenic effect, were highlighted. Interannual variability in the macroinfauna was attributed to the synergy of several environmental factors. Undoubtedly, compounds derived from fossil fuels had a significant disturbance role, but their source remains uncertain.
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Affiliation(s)
- Diana L Salcedo
- Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Circuito Ciudad Universitaria s/n, 04510 México, D.F., Mexico
| | - Luis A Soto
- Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Circuito Ciudad Universitaria s/n, 04510 México, D.F., Mexico.
| | - Alejandro Estradas-Romero
- Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Circuito Ciudad Universitaria s/n, 04510 México, D.F., Mexico
| | - Alfonso V Botello
- Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Circuito Ciudad Universitaria s/n, 04510 México, D.F., Mexico
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Soto LA, Rafat M, Vilalta Colomer M, Giaccia A, Graves E. Abstract 1645: Tumor-associated macrophages enhance DNA damage repair and improve survival of murine breast cancers after irradiation. Cancer Res 2016. [DOI: 10.1158/1538-7445.am2016-1645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Tumor-associated macrophages (TAMs) are known to promote physiological processes that drive tumor progression and survival, including angiogenesis, immunosuppression, and invasion. While most studies on TAMs have focused on the molecular mechanisms by which TAMs drive these processes, less focus has been given to direct effects that TAMs may exert on tumor cells. It is known that monocytes are recruited to tumor sites after radiotherapy and support tumor regrowth. In this study we sought to determine if TAMs are able to exert a direct, protective effect on tumor cells against radiotherapy in vitro. We used murine 4T1 cells, a well-characterized animal model for breast cancer, and murine RAW264.7 macrophages to carry out co-culture experiments. Co-culture of 4T1 cells with RAW264.7 macrophages resulted in increased 4T1 cell survival rates post-irradiation compared to 4T1 cells cultured alone. We further determined that this effect is not contact-dependent but mediated through macrophage secreted factors. Next, we tested whether co-culturing RAW264.7 macrophages with 4T1 cells induced macrophage polarization to an M2/TAM phenotype. Using antibodies against M2 markers and FACS, we found that co-culture of RAW macrophages with 4T1 cells polarizes these macrophages toward an M2 phenotype. We hypothesized that the increased 4T1 cell survival rates were mediated by an enhanced DNA damage repair mechanism induced by TAMs. We tested this via a combination of immunofluorescence against phosphorylated histone H2AX and comet assays. We show that co-culture of 4T1 cells with TAMs after irradiation results in lower 4T1 cell levels of DNA damage and a faster decrease in DNA damage over time compared to 4T1 cells alone. Future work will focus on characterizing the molecular mechanism through which TAMs induce this enhanced DNA damage repair response in 4T1 cells after irradiation and we will test whether such response occurs in vivo after radiotherapy. In conclusion, we show that TAMs confer resistance against ionizing radiation to tumor cells in vitro and that this resistance is driven by an enhanced DNA damage repair mechanism in tumor cells induced by TAM secreted factors.
Citation Format: Luis A. Soto, Marjan Rafat, Marta Vilalta Colomer, Amato Giaccia, Edward Graves. Tumor-associated macrophages enhance DNA damage repair and improve survival of murine breast cancers after irradiation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1645.
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de la Lanza Espino G, Soto LA. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba. PLoS One 2015; 10:e0125562. [PMID: 26110791 PMCID: PMC4482514 DOI: 10.1371/journal.pone.0125562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 03/25/2015] [Indexed: 11/18/2022] Open
Abstract
The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC), nitrogen (TN), phosphorus (TP), elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm) displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g-1). Sites near the island’s lower slope had lower TOC average concentrations (158-333 µmol g-1) than those closer to the channel axis (averaging 341-516 µmol g-1; p <0.05). The TN concentrations near the lower slope attained 0.11% (80 µmol g-1), whereas, towards the channel axis, they decreased to 0.07% (55 µmol g-1; p<0.05). The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4) indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol g-1; 0.12% to 0.16%) than those near the channel axis (50.0 to 66 µmol g-1; 0.15 to 0.21%). C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP). We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.
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Affiliation(s)
| | - Luis A. Soto
- Instituto de Ciencias del Mar y Limnología, UNAM México D.F., México
- * E-mail: (LAS)
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Turra A, Cróquer A, Carranza A, Mansilla A, Areces AJ, Werlinger C, Martínez-Bayón C, Nassar CAG, Plastino E, Schwindt E, Scarabino F, Chow F, Figueroa FL, Berchez F, Hall-Spencer JM, Soto LA, Buckeridge MS, Copertino MS, de Széchy MTM, Ghilardi-Lopes NP, Horta P, Coutinho R, Fraschetti S, Leão ZMDAN. Global environmental changes: setting priorities for Latin American coastal habitats. Glob Chang Biol 2013; 19:1965-1969. [PMID: 23504820 DOI: 10.1111/gcb.12186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 02/13/2013] [Indexed: 06/01/2023]
Abstract
As the effects of the Global Climate Changes on the costal regions of Central and South Americas advance, there is proportionally little research being made to understand such impacts. This commentary puts forward a series of propositions of strategies to improve performance of Central and South American science and policy making in order to cope with the future impacts of the Global Climate Changes in their coastal habitats.
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Affiliation(s)
- Alexander Turra
- Departamento de Oceanografia Biológica, Universiade de São Paulo, Cidade Universitária, Praça do Oceanográfico, Sao Paulo, Brazil
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Corona A, Soto LA, Sánchez AJ. Epibenthic amphipod abundance and predation efficiency of the pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) in habitats with different physical complexity in a tropical estuarine system. J Exp Mar Biol Ecol 2000; 253:33-48. [PMID: 11018235 DOI: 10.1016/s0022-0981(00)00236-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Amphipod abundance and biomass were determined in soft-bottom substrates (SBS), monospecific Thalassia testudinum patches and T. testudinum with attached macroalgae (SAV) from Términos Lagoon. Amphipods were absent in SBS, and their density and biomass were higher in SAV (3351 individualsm(-2), 1718 mg AFDWm(-2)) than in T. testudinum (1220 indm(-2), 625 mg AFDWm(-2)). Although macroalgae and seagrasses are recognised as an alternative refuge against predation for amphipods, the high abundance of amphipods in SAV suggests that macroalgae represent a habitat that provides greater food availability. Pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) consumption rate (Mo) of epibenthic amphipods was experimentally evaluated. Mo intensifies as prey density increases and varied from 0.39 to 2.39 mg AFDWh(-1). Predation efficiency of F. duorarum on epibenthic amphipods was also evaluated in four artificial habitats with different physical complexity: soft-bottom substrates (SBS), small woody debris (SWD), seagrasses with densities of 300 and 1200 shootsm(-2) (S300 and S1200, respectively), macroalgae (MA), and at two prey densities (962 and 2406 indm(-2)). Amphipod consumption rate by F. duorarum varied from 1.20 to 2.07 indh(-1) in S1200 and MA, respectively. Habitat complexity had a significant effect on consumption rate, but prey density did not. Habitat physical complexity and predation efficiency maintained an inverse and a non-linear relationship. Presumably, the decrease in predation efficiency in association with the habitat complexity is due to the differential refuge value of these habitats. However, predation efficiency may also be influenced by either the microhabitat use by amphipods, the shrimp's dependence on seagrasses, or by differences in habitat value caused by the diel behavioural distribution pattern of amphipods and shrimp. Both field and experimental results highlight the importance of evaluating the relative value of tropical estuarine habitats through the study of the relationship between habitat physical complexity and predator-prey interactions. They also emphasise that inherent biological and ethological factors of the predator and prey involved, coupled to spatial and temporal variations in the habitat, should also be considered.
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Affiliation(s)
- A Corona
- Laboratorio de Ecología del Bentos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Circuito exterior s/n, A.P. 70-305, 04510, D.F., Mexico, Mexico
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