Association of mitochondrial DNA content in peripheral blood with cancer-related fatigue and chemotherapy-related cognitive impairment in early-stage breast cancer patients: a prospective cohort study

Mitochondria transcription and cancer

Mitochondria are major organelles involved in several processes related to energy supply, metabolism, and cell proliferation. The mitochondria function is transcriptionally regulated by mitochondria DNA (mtDNA), which encodes the key proteins in the electron transport chain that is indispensable for oxidative phosphorylation (OXPHOS). Mitochondrial transcriptional abnormalities are closely related to a variety of human diseases, such as cardiovascular diseases, and diabetes. The mitochondria transcription is regulated by the mtDNA, mitochondrial RNA polymerase (POLRMT), two transcription factors (TFAM and TF2BM), one transcription elongation (TEFM), and one known transcription termination factor (mTERFs). Dysregulation of these factors directly leads to altered expression of mtDNA in tumor cells, resulting in cellular metabolic reprogramming and mitochondrial dysfunction. This dysregulation plays a role in modulating tumor progression. Therefore, understanding the role of mitochondrial transcription in cancer can have implications for cancer diagnosis, prognosis, and treatment. Targeting mitochondrial transcription or related pathways may provide potential therapeutic strategies for cancer treatment. Additionally, assessing mitochondrial transcriptional profiles or biomarkers in cancer cells or patient samples may offer diagnostic or prognostic information.

Biological mechanisms of cancer-related fatigue in breast cancer survivors after treatment: a scoping review

PURPOSE

Cancer-related fatigue (CRF) is the most common symptom experienced by cancer survivors. It is a multidimensional symptom affecting physical, emotional, and/or cognitive spheres, different from other types of fatigue. Characteristically is not alleviated by sleep or rest. CRF could have specific features in breast cancer survivors (BCS), because of sex, hormones, and distinct treatments. On the other hand, more than 25% of BCS report persistent CRF for 10 years or more after the diagnosis. The present study aims to recapitulate the knowledge about the biological mechanisms that potentially drive CRF in BCS after treatment.

METHODS

To answer a broad question, a scoping review methodology was used. Data were collated from three bibliographic databases: PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL). Studies were selected if they had included more than 20 BCS, after finishing their treatment, fatigue was measured with a quantitative scale and biomarkers were analyzed.

RESULTS

The final database was composed of 1896 records. Sixty-four studies finally met the eligibility criteria. Inflammation (61%), hypothalamic-pituitary-adrenal (HPA) axis dysregulation (14%), autonomic nervous system (ANS) dysfunction (11%), and diet (9%) were the biological pathways most frequently studied. Unfortunately, results from studies about inflammation and HPA axis show many inconsistencies.

CONCLUSION

More research about the role of ANS dysfunction and diet on the pathogenesis of CRF would be warranted according to the results of the review. There are some fields such as endocannabinoid systems, mitochondrial dysfunction, gut microbiota, and oxidative stress that have been insufficiently explored.

IMPLICATIONS FOR CANCER SURVIVORS

To widen the scope of future research in the physiopathology of CRF, it is necessary to identify mechanisms that would be potentially involved and have been insufficiently explored. Because of the high prevalence of CRF in BCS and the tremendous impact that fatigue has in their quality of life, it is essential to improve the efficacy of the treatments through a good knowledge of the biological basis of CRF.

Cancer-related cognitive impairment in racial and ethnic minority groups: a scoping review

PURPOSE

Disparities in cognitive function among racial and ethnic groups have been reported in non-cancer conditions, but cancer-related cognitive impairment (CRCI) in racial and ethnic minority groups is poorly understood. We aimed to synthesize and characterize the available literature about CRCI in racial and ethnic minority populations.

METHODS

We conducted a scoping review in the PubMed, PsycInfo, and Cumulative Index to Nursing and Allied Health Literature databases. Articles were included if they were published in English or Spanish, reported cognitive functioning in adults diagnosed with cancer, and characterized the race or ethnicity of the participants. Literature reviews, commentaries, letters to the editor, and gray literature were excluded.

RESULTS

Seventy-four articles met the inclusion criteria, but only 33.8% differentiated the CRCI findings by racial or ethnic subgroups. There were associations between cognitive outcomes and the participants' race or ethnicity. Additionally, some studies found that Black and non-white individuals with cancer were more likely to experience CRCI than their white counterparts. Biological, sociocultural, and instrumentation factors were associated with CRCI differences between racial and ethnic groups.

CONCLUSIONS

Our findings indicate that racial and ethnic minoritized individuals  may be disparately affected by CRCI. Future research should use standardized guidelines for measuring and reporting the self-identified racial and ethnic composition of the sample; differentiate CRCI findings by racial and ethnic subgroups; consider the influence of structural racism in health outcomes; and develop strategies to promote the participation of members of racial and ethnic minority groups.

Blood-Based Biomarkers of Cancer-Related Cognitive Impairment in Non-Central Nervous System Cancer: A Scoping Review

This scoping review was designed to synthesize the extant literature on associations between subjective and/or objective measures of cancer-related cognitive impairment (CRCI) and blood-based biomarkers in adults with non-central nervous system cancers. The literature search was done for studies published from the start of each database searched (i.e., MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, grey literature) through to October 20, 2021. A total of 95 studies are included in this review. Of note, a wide variety of biomarkers were evaluated. Most studies evaluated patients with breast cancer. A variety of cognitive assessment measures were used. The most consistent significant findings were with various subjective and objective measures of CRCI and levels of interleukin-6 and tumor necrosis factor. Overall, biomarker research is in an exploratory phase. However, this review synthesizes findings and proposes directions for future research.

The Effects of a Mediterranean Diet Intervention on Cancer-Related Fatigue for Patients Undergoing Chemotherapy: A Pilot Randomized Controlled Trial

Cancer-related fatigue is a common, burdensome symptom of cancer and a side-effect of chemotherapy. While a Mediterranean Diet (MedDiet) promotes energy metabolism and overall health, its effects on cancer-related fatigue remain unknown. In a randomized controlled trial, we evaluated a rigorous MedDiet intervention for feasibility and safety as well as preliminary effects on cancer-related fatigue and metabolism compared to usual care. Participants had stage I−III cancer and at least six weeks of chemotherapy scheduled. After baseline assessments, randomization occurred 2:1, MedDiet:usual care. Measures were collected at baseline, week 4, and week 8 including MedDiet adherence (score 0−14), dietary intake, and blood-based metabolic measures. Mitochondrial respiration from freshly isolated T cells was measured at baseline and four weeks. Participants (n = 33) were 51.0 ± 14.6 years old, 94% were female, and 91% were being treated for breast cancer. The study was feasible, with 100% completing the study and >70% increasing their MedDiet adherence at four and eight weeks compared to baseline. Overall, the MedDiet intervention vs. usual care had a small-moderate effect on change in fatigue at weeks 4 and 8 (ES = 0.31, 0.25, respectively). For those with a baseline MedDiet score <5 (n = 21), the MedDiet intervention had a moderate-large effect of 0.67 and 0.48 at weeks 4 and 8, respectively. The MedDiet did not affect blood-based lipids, though it had a beneficial effect on fructosamine (ES = −0.55). Fatigue was associated with mitochondrial dysfunction including lower basal respiration, maximal respiration, and spare capacity (p < 0.05 for FACIT-F fatigue subscale and BFI, usual fatigue). In conclusion, the MedDiet was feasible and attenuated cancer-related fatigue among patients undergoing chemotherapy, especially those with lower MedDiet scores at baseline.

Exploratory Analysis of Associations Between Whole Blood Mitochondrial Gene Expression and Cancer-Related Fatigue Among Breast Cancer Survivors

BACKGROUND

Cancer-related fatigue is a prevalent, debilitating, and persistent condition. Mitochondrial dysfunction is a putative contributor to cancer-related fatigue, but relationships between mitochondrial function and cancer-related fatigue are not well understood.

OBJECTIVES

We investigated the relationships between mitochondrial DNA (mtDNA) gene expression and cancer-related fatigue, as well as the effects of fish and soybean oil supplementation on these relationships.

METHODS

A secondary analysis was performed on data from a randomized controlled trial of breast cancer survivors 4-36 months posttreatment with moderate-severe cancer-related fatigue. Participants were randomized to take 6 g fish oil, 6 g soybean oil, or 3 g each daily for 6 weeks. At pre- and postintervention, participants completed the Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire and provided whole blood for assessment of mtDNA gene expression. The expression of 12 protein-encoding genes was reduced to a single dimension using principal component analysis for use in regression analysis. Relationships between mtDNA expression and cancer-related fatigue were assessed using linear regression.

RESULTS

Among 68 participants, cancer-related fatigue improved and expression of all mtDNA genes decreased over 6 weeks with no effect of treatment group on either outcome. Participants with lower baseline mtDNA gene expression had greater improvements in cancer-related fatigue. No significant associations were observed between mtDNA gene expression and cancer-related fatigue at baseline or changes in mtDNA gene expression and changes in cancer-related fatigue.

DISCUSSION

Data from this exploratory study add to the growing literature that mitochondrial dysfunction may contribute to the etiology and pathophysiology of cancer-related fatigue.

Effect of Solution-Focused Therapy on Cancer-Related Fatigue in Patients With Colorectal Cancer Undergoing Chemotherapy: A Randomized Controlled Trial

BACKGROUND

Cancer-related fatigue (CRF) has gained increased attention in the past decade but remains difficult to treat. It is a predictor of patients' overall health and quality of life (QoL). Therefore, controlling fatigue is important for patients with cancer.

OBJECTIVE

The aim of this study was to test the effect of solution-focused therapy (SFT) in reducing CRF and improving QoL in patients with colorectal cancer (CRC) undergoing chemotherapy.

METHODS

A total of 124 patients with CRC undergoing chemotherapy were recruited and randomized to the SFT group or control group. Cancer-related fatigue was measured with the Cancer Fatigue Scale-Chinese version (CFS-C) at baseline, 3 months, and 6 months. Quality of life was measured with the Quality of Life Instruments for Colorectal Cancer Patients at baseline and 6 months.

RESULTS

Of 124 patients, 119 (95.9%) were evaluable. The SFT group showed significantly lower Cancer Fatigue Scale-Chinese version scores than the control group in all subscales and the total scores at 3 months (P < .001). At 6 months, the SFT group had significantly lower scores in cognitive fatigue (P < .001) and total fatigue (P = .005). The CRF of the SFT group decreased in the first 3 months (P = .012) but increased at 6 months (P < .001). The SFT group had significantly higher scores in the physical and psychological domains and overall QoL (P = .002, P <.001, and P = .02) than the control group at 6 months.

CONCLUSION

Solution-focused therapy may decrease the CRF and improve QoL during chemotherapy for patients with CRC.

IMPLICATION FOR PRACTICE

Solution-focused therapy can be implemented to relieve fatigue and improve QoL in patients with CRC.

Neurotoxicity prevention with a multimodal program (ATENTO) prior to cancer treatment versus throughout cancer treatment in women newly diagnosed for breast cancer: Protocol for a randomized clinical trial

A current challenge in breast cancer (BC) patients is how to reduce the side effects of cancer and cancer treatments and prevent a decrease in quality of life (QoL). Neurotoxic side effects, especially from chemotherapy, are present in up to 75% of women with BC, which implies a large impact on QoL. There is a special interest in the preventive possibilities of therapeutic exercise (TE) for these neurological sequelae, and the benefits of TE could be improved when it is combined with vagal activation techniques (VATs). This superiority randomized controlled trial aims to examine the feasibility and efficacy of an 8-week multimodal intervention (ATENTO) based on moderate-vigorous intensity and individualized TE (aerobic and strength exercises) and VAT (myofascial and breathing exercises), on neurotoxicity prevention in women with BC before starting adjuvant chemotherapy (ATENTO-B) versus throughout adjuvant chemotherapy (ATENTO-T). A sample of 56 women newly diagnosed with BC, as calculated with a power of 85%, will be randomly allocated into these two groups. This study could provide an impetus for the introduction of early multimodal intervention methods to prevent neurotoxicity and consequently avoid the QoL deterioration that BC patients presently suffer throughout their treatments.

A study protocol for HEalth-Related quality of life-intervention in survivors of Breast and other cancers experiencing cancer-related fatigue using TraditionAL Chinese Medicine: the HERBAL trial

BACKGROUND

Cancer-related fatigue (CRF) is a debilitating condition which commonly affects cancer survivors. The management of CRF remains a challenge due to the lack of effective pharmacological interventions. Traditional Chinese medicine (TCM) could be a potential therapeutic option for CRF. The modified Xiang Bei Yang Rong Tang (XBYRT) is a TCM herbal decoction, formulated to improve fatigue symptoms in cancer survivors. This clinical trial aims to evaluate the efficacy and safety of XBYRT in improving CRF and quality of life (QOL) of cancer survivors.

METHODS

This is a single centre, randomized, double-blind, placebo-controlled, parallel trial. Eighty cancer survivors will be recruited and randomized to receive the XBYRT or placebo decoction, in a ratio of 1:1. Participants will consume the XBYRT/placebo decoction daily for 8 weeks and undergo assessments at baseline and 4, 8 and 10 weeks after baseline. The participants will be assessed for patient-reported outcomes (PRO), blood biomarkers and adverse events at each time point. The primary outcome is the overall health and QOL status, at 8 weeks follow-up. The secondary outcomes are the effects of XBYRT on fatigue levels, cancer-related cognitive impairment and QOL, as assessed by PRO. The incidence of adverse events and the effects of the XBYRT decoction on blood biomarkers associated with CRF will also be evaluated.

DISCUSSION

Efficacy and safety outcomes from this trial will provide important clinical data to guide future large-scale randomized controlled trials, and the evaluation of the objective blood biomarkers can help to delineate the biological mechanisms of CRF.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT04104113 . Registered on 26 September 2019.

Association of mitochondrial DNA content and displacement loop region sequence variations with cancer-related fatigue in breast cancer survivors receiving chemotherapy

Cancer-related fatigue (CRF) is characterized by a lack of energy, and mitochondrial dysfunction is postulated to contribute to its etiology. This prospective cohort study assesses the self-reported fatigue levels of early-stage breast cancer patients using the validated Multi-Dimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) and blood samples drawn at three time points: before treatment, approximately 6 weeks, and 12 weeks after the initiation of chemotherapy. The aim of this study is to evaluate mitochondrial measures with CRF, over the course of chemotherapy using mitochondrial DNA (mtDNA content) and displacement loop (D-loop) region sequence variations at nucleotide positions 303, 489 and 514. The relative mtDNA copy number was determined via real-time quantitative polymerase chain reaction and compared between study time points and D-loop sequence variants. The association of mtDNA content with MFSI-SF total and sub-domain scores was analyzed in a sample of 155 patients (mean age ± SD: 51.7 ± 8.8 years). The median mtDNA content decreased over 12 weeks after the initiation of chemotherapy (p < 0.001). Baseline mtDNA content was lower for nucleotide position 303 in sequence variations than for the reference sequence (67.2 copies vs 79.1 copies, p = 0.03). Physical fatigue negatively correlated with mtDNA content in both unadjusted (β = -0.0075, p = 0.048) and adjusted models (β = -0.0062, p = 0.042), accounting for age, anxiety, insomnia, haemoglobin levels and body mass index. Our findings add to the literature indicating that mitochondrial function serves as an important target for mitigating CRF.

Systematic review of longitudinal studies on chemotherapy-associated subjective cognitive impairment in cancer patients

OBJECTIVES

This systematic review of longitudinal studies, assessing subjective cognitive impairment (SCI) reported by adult cancer patients, aimed to summarize evidence on the impact of chemotherapy on SCI, identify moderators of SCI, and evaluate methodological issues.

METHODS

Data accrued from Pubmed, EMBASE, CINAHL, PsychInfo, and the Cochrane library. Inclusion criteria were original studies, an exclusively adult sample, valid and reliable subjective cognitive measures, and at least one baseline data point prior to and another after the initiation of chemotherapy. Data were collected on the sample composition, data-collection time points, outcome measures, statistical analysis, and major findings (ie, longitudinal changes in prevalence, severity, and associated factors).

RESULTS

Forty articles published between 2004 and 2019 were retained: 21 examined chemotherapy-treated patients only, and 19 employed control groups. Findings were mixed, with slightly more studies supporting the impact of chemotherapy on SCI. SCI tended to be more prevalent and severe after initiating chemotherapy, compared with patients' own baseline and controls not treated with chemotherapy. Impact appeared to be acute and more likely limited to subsamples. Most studies examining non-breast-cancer samples reported the lack or limited impact of chemotherapy on SCI. The most consistent moderators were depression and fatigue. Methodological issues regarding sampling design, measurement, and statistical analysis were discussed.

CONCLUSION

More rigorously designed longitudinal studies would clarify direct and indirect effects of chemotherapy on SCI.

Cancer-related cognitive impairment: an update on state of the art, detection, and management strategies in cancer survivors

BACKGROUND

Advances in diagnostic and therapeutic strategies in oncology have significantly increased the chance of survival of cancer patients, even those with metastatic disease. However, cancer-related cognitive impairment (CRCI) is frequently reported in patients treated for non-central nervous system cancers, particularly during and after chemotherapy.

DESIGN

This review provides an update of the state of the art based on PubMed searches between 2012 and March 2019 on 'cognition', 'cancer', 'antineoplastic agents' or 'chemotherapy'. It includes the most recent clinical, imaging and pre-clinical data and reports management strategies of CRCI.

RESULTS

Evidence obtained primarily from studies on breast cancer patients highlight memory, processing speed, attention and executive functions as the most cognitive domains impaired post-chemotherapy. Recent investigations established that other cancer treatments, such as hormone therapies and targeted therapies, can also induce cognitive deficits. Knowledge regarding predisposing factors, biological markers or brain functions associated with CRCI has improved. Factors such as age and genetic polymorphisms of apolipoprotein E, catechol-O-methyltransferase and BDNF may predispose individuals to a higher risk of cognitive impairment. Poor performance on neuropsychological tests were associated with volume reduction in grey matter, less connectivity and activation after chemotherapy. In animals, hippocampus-based memory and executive functions, mediated by the frontal lobes, were shown to be particularly susceptible to the effects of chemotherapy. It involves altered neurogenesis, mitochondrial dysfunction or brain cytokine response. An important next step is to identify strategies for managing cognitive difficulties, with primary studies to assess cognitive training and physical exercise regimens.

CONCLUSIONS

CRCI is not limited to chemotherapy. A multidisciplinary approach has improved our knowledge of the complex mechanisms involved. Nowadays, studies evaluating cognitive rehabilitation programmes are encouraged to help patients cope with cognitive difficulties and improve quality of life during and after cancer.

The relationship between neutrophil-lymphocyte ratio and onset of lactation among postpartum women: A prospective observational cohort study

BACKGROUND

Delayed onset of lactation is a key factor in the low rate of exclusive breast-feeding in 6 months after caesarean section. The mechanism of delayed onset of lactation is not clear. Milk production depends largely on mitochondrial adenosine triphosphate synthesis, and the neutrophil-lymphocyte ratio is closely related to mitochondrial deoxyribonucleic acid copy number and adenosine triphosphate production. Presently, it is unclear whether a difference in the neutrophil-lymphocyte ratio exists between those undergoing vaginal delivery and those undergoing caesarean delivery and, if so, whether the difference correlates to the time of onset of lactation.

OBJECTIVES

To identify whether the neutrophil-lymphocyte ratio at 24 hours after delivery is different between mothers delivering by caesarean section and those giving birth vaginally and whether the neutrophil-lymphocyte ratio is related to the delayed onset of lactation.

DESIGN

The study adopted a prospective cohort study design.

SETTINGS

Maternity units of an Obstetrics & Gynecology Hospital.

PARTICIPANTS

327 mother-infant pairs who met inclusion/exclusion criteria and were followed up to the time of onset of lactation.

METHODS

Mother-infant pairs were allocated to the vaginal birth group or the caesarean section group according to birth method. The neutrophil-lymphocyte ratio was calculated as the absolute value of neutrophils divided by the absolute value of lymphocytes based on full blood counts. Before delivery, full blood counts were obtained from medical records. After delivery, blood samples were drawn 24 hours postpartum, and blood cells were classified and counted. The onset of lactation was confirmed by the maternal perception of breast fullness. The neutrophil-lymphocyte ratio and its relationship with lactation onset were analyzed by multivariable regression.

RESULTS

The neutrophil-lymphocyte ratios of both groups were elevated after delivery. Based on the covariance analysis, after adjusting for baseline full blood counts before delivery, the neutrophil-lymphocyte ratio in the caesarean group was higher than the ratio in the vaginal group after delivery (p = .000). In addition, after adjustment for confounding factors, multivariable regression analyses showed that an increased neutrophil-lymphocyte ratio was correlated with delayed onset of lactation (95% confidence interval 0.285-1.646).

CONCLUSIONS

The neutrophil-lymphocyte ratio in the caesarean section group was higher than that in the vaginal delivery group and was related to a delayed onset of lactation. Given the decreased mitochondrial copy number in the elevated neutrophil-lymphocyte ratio and therefore the associated reduction in adenosine triphosphate synthesis, these findings may elucidate the mechanism for delayed onset of lactation in caesarean section births.

The role of mitochondrial DNA in breast tumors

Somatic variation in mitochondrial DNA (mtDNA) has been described in primary breast tumors, including single-nucleotide variants and variation in the number of mtDNA molecules per cell (mtDNA content). However, there is currently a gap in the knowledge on the link between mitochondrial variation in breast cancer cells and their phenotypic behavior (i.e., tumorigenesis) or outcome. This review focuses on recent findings on mtDNA content and mtDNA somatic mutations in breast cancer and the potential biological impact and clinical relevance.

The role of neuro-immune interactions in cancer-related fatigue: Biobehavioral risk factors and mechanisms

Fatigue is a common and distressing symptom in both patients with cancer and cancer survivors. There is substantial variation in the severity and persistence of cancer-related fatigue that may be driven by individual differences in host factors, including characteristics that predate the cancer experience as well as responses to cancer and its treatment. This review examines biobehavioral risk factors linked to fatigue and the mechanisms through which they influence fatigue across the cancer continuum, with a focus on neuro-immune processes. Among psychosocial risk factors, childhood adversity is a strong and consistent predictor of cancer-related fatigue; other risk factors include history of depression, catastrophizing, lack of physical activity, and sleep disturbance, with compelling preliminary evidence for loneliness and trait anxiety. Among biologic systems, initial work suggests that alterations in immune, neuroendocrine, and neural processes are associated with fatigue. The identification of key risk factors and underlying mechanisms is critical for the development and deployment of targeted interventions to reduce the burden of fatigue in the growing population of cancer survivors. Given the multidimensional nature of fatigue, interventions that influence multiple systems may be most effective.