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Sijtsema ND, Lauwers I, Verduijn GM, Hoogeman MS, Poot DH, Hernandez-Tamames JA, van der Lugt A, Capala ME, Petit SF. Relating pre-treatment non-Gaussian intravoxel incoherent motion diffusion-weighted imaging to human papillomavirus status and response in oropharyngeal carcinoma. Phys Imaging Radiat Oncol 2024; 30:100574. [PMID: 38633282 PMCID: PMC11021835 DOI: 10.1016/j.phro.2024.100574] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/29/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024] Open
Abstract
Background and purpose Diffusion-weighted imaging (DWI) is a promising technique for response assessment in head-and-neck cancer. Recently, we optimized Non-Gaussian Intravoxel Incoherent Motion Imaging (NG-IVIM), an extension of the conventional apparent diffusion coefficient (ADC) model, for the head and neck. In the current study, we describe the first application in a group of patients with human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinoma. The aim of this study was to relate ADC and NG-IVIM DWI parameters to HPV status and clinical treatment response. Materials and methods Thirty-six patients (18 HPV-positive, 18 HPV-negative) were prospectively included. Presence of progressive disease was scored within one year. The mean pre-treatment ADC and NG-IVIM parameters in the gross tumor volume were compared between HPV-positive and HPV-negative patients. In HPV-negative patients, ADC and NG-IVIM parameters were compared between patients with and without progressive disease. Results ADC, the NG-IVIM diffusion coefficient D, and perfusion fraction f were significantly higher, while pseudo-diffusion coefficient D* and kurtosis K were significantly lower in the HPV-negative compared to HPV-positive patients. In the HPV-negative group, a significantly lower D was found for patients with progressive disease compared to complete responders. No relation with ADC was observed. Conclusion The results of our single-center study suggest that ADC is related to HPV status, but not an independent response predictor. The NG-IVIM parameter D, however, was independently associated to response in the HPV-negative group. Noteworthy in the opposite direction as previously thought based on ADC.
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Affiliation(s)
- Nienke D. Sijtsema
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Iris Lauwers
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Gerda M. Verduijn
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Mischa S. Hoogeman
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Medical Physics and Informatics, HollandPTC, Delft, the Netherlands
| | - Dirk H.J. Poot
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Juan A. Hernandez-Tamames
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Marta E. Capala
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Steven F. Petit
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, the Netherlands
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Verduijn GM, Sijtsema ND, van Norden Y, Heemsbergen WD, Mast H, Sewnaik A, Chin D, Baker S, Capala ME, van der Lugt A, van Meerten E, Hoogeman MS, Petit SF. Response to the letter-to-the-editor "Comments on: Accounting for fractionation and heterogeneous dose distributions in the modelling of osteoradionecrosis in oropharyngeal carcinoma treatment". Radiother Oncol 2024; 190:110036. [PMID: 38040122 DOI: 10.1016/j.radonc.2023.110036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 12/03/2023]
Affiliation(s)
- Gerda M Verduijn
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands.
| | - Nienke D Sijtsema
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands; Radiology and Nuclear Medicine, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Yvette van Norden
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Wilma D Heemsbergen
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Hetty Mast
- Oral and Maxillofacial Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Aniel Sewnaik
- Otorhinolaryngology and Head and Neck Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Denzel Chin
- Oral and Maxillofacial Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Sarah Baker
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Marta E Capala
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Aad van der Lugt
- Radiology and Nuclear Medicine, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Esther van Meerten
- Medical Oncology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Mischa S Hoogeman
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
| | - Steven F Petit
- Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, the Netherlands
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Verduijn GM, Sijtsema ND, van Norden Y, Heemsbergen WD, Mast H, Sewnaik A, Chin D, Baker S, Capala ME, van der Lugt A, van Meerten E, Hoogeman MS, Petit SF. Accounting for fractionation and heterogeneous dose distributions in the modelling of osteoradionecrosis in oropharyngeal carcinoma treatment. Radiother Oncol 2023; 188:109889. [PMID: 37659662 DOI: 10.1016/j.radonc.2023.109889] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/22/2023] [Accepted: 08/26/2023] [Indexed: 09/04/2023]
Abstract
BACKGROUND AND PURPOSE Osteoradionecrosis (ORN) of the mandible is a severe complication following radiotherapy (RT). With a renewed interest in hypofractionation for head and neck radiotherapy, more information concerning ORN development after high fraction doses is important. The aim of this explorative study was to develop a model for ORN risk prediction applicable across different fractionation schemes using Equivalent Uniform Doses (EUD). MATERIAL AND METHODS We performed a retrospective cohort study in 334 oropharyngeal squamous cell carcinoma (OPSCC) patients treated with either a hypofractionated Stereotactic Body Radiation Therapy (HF-SBRT) boost or conventional Intensity Modulated Radiation Therapy (IMRT). ORN was scored with the CTCAE v5.0. HF-SBRT and IMRT dose distributions were converted into equivalent dose in 2 Gy fractions (α/β = 0.85 Gy) and analyzed using EUD. The parameter a that led to an EUD that best discriminated patients with and without grade ≥ 2 ORN was selected. Patient and treatment-related risk factors of ORN were analyzed with uni- and multivariable regression analysis. RESULTS A total of 32 patients (9.6%) developed ORN grade ≥ 2. An EUD(a = 8) best discriminated between ORN and non-ORN (AUC = 0.71). In multivariable regression, pre-RT extractions (SHR = 2.34; p = 0.012), mandibular volume (SHR = 1.04; p = 0.003), and the EUD(a = 8) (SHR = 1.14; p < 0.001) were significantly associated with ORN. CONCLUSION Risk models for ORN based on conventional DVH parameters cannot be directly applied to HF-SBRT fractionation schemes and dose distributions. However, after correcting for fractionation and non-uniform dose distributions using EUD, a single model can distinguish between ORN and non-ORN after conventionally fractionated radiotherapy and hypofractionated boost treatments.
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Affiliation(s)
- Gerda M Verduijn
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands.
| | - Nienke D Sijtsema
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands; Departments of Radiology and Nuclear Medicine, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Yvette van Norden
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Wilma D Heemsbergen
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Hetty Mast
- Departments of Oral and Maxillofacial Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Aniel Sewnaik
- Departments of Otorhinolaryngology and Head and Neck Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Denzel Chin
- Departments of Oral and Maxillofacial Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Sarah Baker
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Marta E Capala
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Aad van der Lugt
- Departments of Radiology and Nuclear Medicine, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Esther van Meerten
- Departments of Medical Oncology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Mischa S Hoogeman
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
| | - Steven F Petit
- Departments of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, The Netherlands
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Ghuijs W, Kemps PG, Capala ME, Verdijk RM, van Halteren AGS, van der Wal RJP, van Laar JAM. Aggressive unifocal bone Langerhans cell histiocytosis with soft tissue extension both responsive to radiotherapy: a case report. Radiat Oncol 2022; 17:137. [PMID: 35915468 PMCID: PMC9344655 DOI: 10.1186/s13014-022-02108-0] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Langerhans cell histiocytosis (LCH) is a rare haematological neoplasm characterized by the accumulation of CD1a+, CD207/Langerin+ histiocytes within inflammatory lesions. LCH can involve any organ, but osteolytic bone lesions are most often encountered. Unifocal bone lesions may regress spontaneously after a thick needle biopsy has been taken. CASE PRESENTATION In this case report, we describe the initial presentation of a single BRAFV600E mutated osteolytic LCH lesion in the left proximal humerus of a 46-year-old previously healthy woman. Despite multiple surgical interventions, she unexpectedly experienced progressive disease manifestation with significant soft tissue extension to the surrounding musculature, subcutis and epidermis. Because the disease manifestation remained loco-regional, radiotherapy (RT) (total dose of 20 Gy in 10 fractions) was initiated. CONCLUSION The patient achieved a complete remission without any side effects. This case highlights that RT is a rational and relative mild local treatment option for patients with aggressive LCH affecting the bone and surrounding soft tissue.
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Affiliation(s)
- Wilmar Ghuijs
- Department of Internal Medicine and Immunology, Erasmus MC University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Paul G Kemps
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marta E Capala
- Department of Radiotherapy, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Robert M Verdijk
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Pathology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Astrid G S van Halteren
- Department of Internal Medicine and Immunology, Erasmus MC University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.,Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.,Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | | | - Jan A M van Laar
- Department of Internal Medicine and Immunology, Erasmus MC University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
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Paczona VR, Capala ME, Deák-Karancsi B, Borzási E, Együd Z, Végváry Z, Kelemen G, Kószó R, Ruskó L, Ferenczi L, Verduijn GM, Petit SF, Oláh J, Cserháti A, Wiesinger F, Hideghéty K. Magnetic Resonance Imaging-Based Delineation of Organs at Risk in the Head and Neck Region. Adv Radiat Oncol 2022; 8:101042. [PMID: 36636382 PMCID: PMC9830100 DOI: 10.1016/j.adro.2022.101042] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/24/2022] [Indexed: 01/16/2023] Open
Abstract
Purpose The aim of this article is to establish a comprehensive contouring guideline for treatment planning using only magnetic resonance images through an up-to-date set of organs at risk (OARs), recommended organ boundaries, and relevant suggestions for the magnetic resonance imaging (MRI)-based delineation of OARs in the head and neck (H&N) region. Methods and Materials After a detailed review of the literature, MRI data were collected from the H&N region of healthy volunteers. OARs were delineated in the axial, coronal, and sagittal planes on T2-weighted sequences. Every contour defined was revised by 4 radiation oncologists and subsequently by 2 independent senior experts (H&N radiation oncologist and radiologist). After revision, the final structures were presented to the consortium partners. Results A definitive consensus was reached after multi-institutional review. On that basis, we provided a detailed anatomic and functional description and specific MRI characteristics of the OARs. Conclusions In the era of precision radiation therapy, the need for well-built, straightforward contouring guidelines is on the rise. Precise, uniform, delineation-based, automated OAR segmentation on MRI may lead to increased accuracy in terms of organ boundaries and analysis of dose-dependent sequelae for an adequate definition of normal tissue complication probability.
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Affiliation(s)
- Viktor R. Paczona
- Department of Oncotherapy, University of Szeged, Szeged, Hungary,Corresponding author: Viktor R. Paczona, MD
| | | | | | - Emőke Borzási
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | - Zsófia Együd
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | - Zoltán Végváry
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | - Gyöngyi Kelemen
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | - Renáta Kószó
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | | | | | | | | | - Judit Oláh
- Department of Oncotherapy, University of Szeged, Szeged, Hungary
| | | | | | - Katalin Hideghéty
- Department of Oncotherapy, University of Szeged, Szeged, Hungary,ELI-HU Non-Profit Ltd, Szeged, Hungary
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Verduijn GM, Capala ME, Sijtsema ND, Lauwers I, Hernandez Tamames JA, Heemsbergen WD, Sewnaik A, Hardillo JA, Mast H, van Norden Y, Jansen MPHM, van der Lugt A, van Gent DC, Hoogeman MS, Mostert B, Petit SF. The COMPLETE trial: HolistiC early respOnse assessMent for oroPharyngeaL cancEr paTiEnts; Protocol for an observational study. BMJ Open 2022; 12:e059345. [PMID: 35584883 PMCID: PMC9119182 DOI: 10.1136/bmjopen-2021-059345] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION The locoregional failure (LRF) rate in human papilloma virus (HPV)-negative oropharyngeal squamous cell carcinoma (OPSCC) remains disappointingly high and toxicity is substantial. Response prediction prior to or early during treatment would provide opportunities for personalised treatment. Currently, there are no accurate predictive models available for correct OPSCC patient selection. Apparently, the pivotal driving forces that determine how a OPSCC responds to treatment, have yet to be elucidated. Therefore, the holistiC early respOnse assessMent for oroPharyngeaL cancer paTiEnts study focuses on a holistic approach to gain insight in novel potential prognostic biomarkers, acquired before and early during treatment, to predict response to treatment in HPV-negative patients with OPSCC. METHODS AND ANALYSIS This single-centre prospective observational study investigates 60 HPV-negative patients with OPSCC scheduled for primary radiotherapy (RT) with cisplatin or cetuximab, according to current clinical practice. A holistic approach will be used that aims to map the macroscopic (with Intra Voxel Incoherent Motion Diffusion Kurtosis Imaging (IVIM-DKI); before, during, and 3 months after RT), microscopic (with biopsies of the primary tumour acquired before treatment and irradiated ex vivo to assess radiosensitivity), and molecular landscape (with circulating tumour DNA (ctDNA) analysed before, during and 3 months after treatment). The main end point is locoregional control (LRC) 2 years after treatment. The primary objective is to determine whether a relative change in the mean of the diffusion coefficient D (an IVIM-DKI parameter) in the primary tumour early during treatment, improves the performance of a predictive model consisting of tumour volume only, for 2 years LRC after treatment. The secondary objectives investigate the potential of other IVIM-DKI parameters, ex vivo sensitivity characteristics, ctDNA, and combinations thereof as potential novel prognostic markers. ETHICS AND DISSEMINATION The study was approved by the Medical Ethical Committee of Erasmus Medical Center. The main results of the trial will be presented in international meetings and medical journals. TRIAL REGISTRATION NUMBER NL8458.
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Affiliation(s)
- Gerda M Verduijn
- Radiotherapy, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marta E Capala
- Radiotherapy, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Nienke D Sijtsema
- Radiotherapy, Erasmus Medical Center, Rotterdam, The Netherlands
- Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Iris Lauwers
- Radiotherapy, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | | | - Aniel Sewnaik
- Otorhinolaryngology and Head and Neck surgery, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jose A Hardillo
- Otorhinolaryngology and Head and Neck surgery, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Hetty Mast
- Oral and Maxillofacial surgery, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | | | - Aad van der Lugt
- Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dik C van Gent
- Molecular Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Bianca Mostert
- Medical Oncology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Steven F Petit
- Radiotherapy, Erasmus Medical Center, Rotterdam, The Netherlands
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Capala ME, Pruis M, Vellenga E, Schuringa JJ. Depletion of SAM50 Specifically Targets BCR-ABL-Expressing Leukemic Stem and Progenitor Cells by Interfering with Mitochondrial Functions. Stem Cells Dev 2016; 25:427-37. [PMID: 26855047 DOI: 10.1089/scd.2015.0151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A high proliferation rate of malignant cells requires an increased energy production, both by anaerobic glucose metabolism and mitochondrial respiration. Moreover, increased levels of mitochondria-produced reactive oxygen species (ROS) promote survival of transformed cells and contribute to the disease progression both in solid tumors and leukemia. Consequently, interfering with mitochondrial metabolism has been used as a strategy to specifically target leukemic cells. SAM50 is a mitochondrial outer membrane protein involved in the formation of mitochondrial intermembrane space bridging (MIB) complex. Although the importance of SAM50 in maintaining MIB integrity and in the assembly of mitochondrial respiratory chain complexes has been described, its specific role in the normal and leukemic hematopoietic cells remains unknown. We observed that human leukemic cells display a specific dependency on SAM50 expression, as downregulation of SAM50 in BCR-ABL-expressing, but not normal CD34(+) human hematopoietic stem and progenitor cells (HSPCs) caused a significant decrease in growth, colony formation, and replating capacity. Mitochondrial functions of BCR-ABL-expressing HSPCs were compromised, as seen by a decreased mitochondrial membrane potential and respiration. This effect of SAM50 downregulation was recapitulated in normal HSPCs exposed to cytokine-rich culture conditions that stimulate proliferation. Both oncogene-transduced and cytokine-stimulated HSPCs showed increased mitochondrial membrane potential and increased ROS levels compared to their normal counterparts. Therefore, we postulate that human leukemic HSPCs are highly dependent on the proper functioning of mitochondria and that disruption of mitochondrial integrity may aid in targeting leukemic cells.
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Affiliation(s)
- Marta E Capala
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Maurien Pruis
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Edo Vellenga
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
| | - Jan Jacob Schuringa
- Department of Experimental Hematology, Cancer Research Center Groningen (CRCG), University Medical Center Groningen, University of Groningen , Groningen, The Netherlands
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Capala ME, Maat H, Bonardi F, van den Boom V, Kuipers J, Vellenga E, Giepmans BNG, Schuringa JJ. Mitochondrial Dysfunction in Human Leukemic Stem/Progenitor Cells upon Loss of RAC2. PLoS One 2015; 10:e0128585. [PMID: 26016997 PMCID: PMC4446344 DOI: 10.1371/journal.pone.0128585] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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: 01/29/2015] [Accepted: 04/28/2015] [Indexed: 11/18/2022] Open
Abstract
Leukemic stem cells (LSCs) reside within bone marrow niches that maintain their relatively quiescent state and convey resistance to conventional treatment. Many of the microenvironmental signals converge on RAC GTPases. Although it has become clear that RAC proteins fulfill important roles in the hematopoietic compartment, little has been revealed about the downstream effectors and molecular mechanisms. We observed that in BCR-ABL-transduced human hematopoietic stem/progenitor cells (HSPCs) depletion of RAC2 but not RAC1 induced a marked and immediate decrease in proliferation, progenitor frequency, cobblestone formation and replating capacity, indicative for reduced self-renewal. Cell cycle analyses showed reduced cell cycle activity in RAC2-depleted BCR-ABL leukemic cobblestones coinciding with an increased apoptosis. Moreover, a decrease in mitochondrial membrane potential was observed upon RAC2 downregulation, paralleled by severe mitochondrial ultrastructural malformations as determined by automated electron microscopy. Proteome analysis revealed that RAC2 specifically interacted with a set of mitochondrial proteins including mitochondrial transport proteins SAM50 and Metaxin 1, and interactions were confirmed in independent co-immunoprecipitation studies. Downregulation of SAM50 also impaired the proliferation and replating capacity of BCR-ABL-expressing cells, again associated with a decreased mitochondrial membrane potential. Taken together, these data suggest an important role for RAC2 in maintaining mitochondrial integrity.
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Affiliation(s)
- Marta E. Capala
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Henny Maat
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Francesco Bonardi
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Vincent van den Boom
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Jeroen Kuipers
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Edo Vellenga
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Ben N. G. Giepmans
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
| | - Jan Jacob Schuringa
- Department of Experimental Hematology, Cancer Research Center Groningen, Groningen, the Netherlands
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