Our goal was to develop a practical protocol to evaluate mitochondrial dysfunction associated with fatigue in cancer patients. This innovative protocol is optimized for clinical use involving only standard phlebotomy and basic laboratory procedures.
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Method Article
Evaluating the Role of Mitochondrial Function in Cancer-related Fatigue
In This Article
Summary
Abstract
Fatigue is a common and debilitating condition that affects most cancer patients. To date, fatigue remains poorly characterized with no diagnostic test to objectively measure the severity of this condition. Here we describe an optimized method for assessing mitochondrial function of PBMCs collected from fatigued cancer patients. Using a compact extracellular flux system and sequential injection of respiratory inhibitors, we examined PBMC mitochondrial functional status by measuring basal mitochondrial respiration, spare respiratory capacity, and energy phenotype, which describes the preferred energy pathway to respond to stress. Fresh PBMCs are readily available in the clinical setting using standard phlebotomy. The entire assay described in this protocol can be completed in less than 4 hours without the involvement of complex biochemical techniques. Additionally, we describe a normalization method that is necessary for obtaining reproducible data. The simple procedure and normalization methods presented allow for repeated sample collection from the same patient and generation of reproducible data that can be compared between time points to evaluate potential treatment effects.
Introduction
Fatigue is a prevalent and distressing condition that has a negative impact on the quality of life of cancer patients1. To this date, cancer fatigue remains poorly defined and relies only on subjective reporting by patients2. Therefore, there is an urgent need to identify an easily adaptable diagnostic laboratory test to objectively characterize fatigue in the clinical setting3,4.
Multiple underlying mechanisms, including mitochondria dysfunction, have been proposed to cause fatigue5. Mitochondria are the powerh....
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Protocol
The current study (NCT00852111) was approved by the Institutional Review Board (IRB) of the National Institutes of Health (NIH), Bethesda, Maryland. Participants enrolled in this study were euthymic men, 18 years of age or older, who were diagnosed with non-metastatic prostate cancer with or without prior prostatectomy and were scheduled to receive external beam radiation therapy (EBRT). Potential participants were excluded if they had a progressive disease that could cause significant fatigue, had psychiatric disease within the past five years, had uncorrected hypothyroidism or anemia, or had a second malignancy. Individuals who used sedatives, steroids, or non-stero....
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Results
The Mito Stress Test relies on measuring oxygen consumption rate (OCR) after sequential injection of various respiratory inhibitors to map a complete mitochondrial profile. OCR measurements after each drug injection can be used to calculate the following parameters related to mitochondrial health: Basal OCR is first measured before any drug injection to assess oxygen consumption needed to meet resting level ATP demand. Basal respiration is calculated by subtracting non-mi.......
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Discussion
Fatigue in cancer patients is a debilitating condition that is not well defined or characterized1. Diagnosis of fatigue entirely relies on subjective reporting and there is no current diagnostic standard or treatment for this condition, largely due to a lack of understanding in its pathobiology2. Of the proposed mechanisms underlying fatigue in cancer patients, impairment in mitochondrial function is one of the most therapeutically targetable pathways. Therefore, we develop.......
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Disclosures
The authors have nothing to disclose.
Acknowledgements
This study is fully supported by the Division of Intramural Research of the National Institute of Nursing Research of the NIH, Bethesda, Maryland.
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| CPT Mononuclear Cells Preparation Tube | BD Biosciences | 362761 | For isolating PBMCs following phlebotomy |
| RPMI-1640 | Corning | 10-040 | For making growth media for PBMCs |
| Fetal bovine serum (FBS) | Corning | 35-010-CV | For making growth media for PBMCs |
| Penicillin/Streptomycin | ThermoFisher | 15140122 | For making growth media for PBMCs |
| Cell-Tak | Corning | 354240 | Cell and Tissue adhesive solution; allows suspension cells to adhere to the surface |
| Seahorse XF Calibrant Solution | Agilent | 103059-000 | For hydrating cartridges |
| XFp Fluxpak (miniplates and sensor cartridges) | Agilent | 103022-100 | Contains XFp cell culture miniplates and sensor cartridges |
| XF base media | Agilent | 103335-100 | For making XF assay media |
| 45% cell culture D-(+)-Glucose solution | Corning | 25-037-CI | For making XF assay media |
| Sodium pyruvate solution | Corning | 25-000-CI | For making XF assay media |
| L-glutamine solution | ThermoFisher | 25030081 | For making XF assay media |
| Seahorse XFp Mito Stress Test Kit | Agilent | 103010-100 | Contains oligomycin, FCCP, antimycin A/rotenone |
| CyQUANT Direct Cell Proliferation Assay | ThermoFisher | C35011 | For quantification of live cells and data normalization |
| Seahorse XFp Analyzer | Agilent | S7802AEA | For measuring mitochondrial function in live cells |
| Cytation 5 Cell Imaging Multi-Mode Reader (or any instrument that can quantify fluorescent cells in a plate) | BioTek | BTCYT5PV | For quantification of live cells and data normalization |
References
- Berger, A. M., et al. Cancer-Related Fatigue, Version 2.2015. Journal of the National Comprehensive Cancer Network. 13 (8), 1012-1039 (2015).
- Feng, L. R., Dickinson, K., Kline, N., Saligan, L. N. Different phenotyping approaches lead to dissimilar biologic profiles in men with chronic fatigue following radiation therapy. Journal of Pain and Symptom Management. 52 (6), 832-840 (2016).
- Feng, L. R., et al.
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