A Longitudinal Study of BDNF Promoter Methylation and Depression in Breast Cancer

Epigenetic mechanisms of rapid-acting antidepressants

BACKGROUND

Rapid-acting antidepressants (RAADs), including dissociative anesthetics, psychedelics, and empathogens, elicit rapid and sustained therapeutic improvements in psychiatric disorders by purportedly modulating neuroplasticity, neurotransmission, and immunity. These outcomes may be mediated by, or result in, an acute and/or sustained entrainment of epigenetic processes, which remodel chromatin structure and alter DNA accessibility to regulate gene expression.

METHODS

In this perspective, we present an overview of the known mechanisms, knowledge gaps, and future directions surrounding the epigenetic effects of RAADs, with a focus on the regulation of stress-responsive DNA and brain regions, and on the comparison with conventional antidepressants.

MAIN BODY

Preliminary correlative evidence indicates that administration of RAADs is accompanied by epigenetic effects which are similar to those elicited by conventional antidepressants. These include changes in DNA methylation, post-translational modifications of histones, and differential regulation of non-coding RNAs in stress-responsive chromatin areas involved in neurotrophism, neurotransmission, and immunomodulation, in stress-responsive brain regions. Whether these epigenetic changes causally contribute to the therapeutic effects of RAADs, are a consequence thereof, or are unrelated, remains unknown. Moreover, the potential cell type-specificity and mechanisms involved are yet to be fully elucidated. Candidate mechanisms include neuronal activity- and serotonin and Tropomyosine Receptor Kinase B (TRKB) signaling-mediated epigenetic changes, and direct interaction with DNA, histones, or chromatin remodeling complexes.

CONCLUSION

Correlative evidence suggests that epigenetic changes induced by RAADs accompany therapeutic and side effects, although causation, mechanisms, and cell type-specificity remain largely unknown. Addressing these research gaps may lead to the development of novel neuroepigenetics-based precision therapeutics.

DNA Methylation Patterns in Relation to Acute Severity and Duration of Anxiety and Depression

Depression and anxiety are common mental disorders that often occur together. Stress is an important risk factor for both disorders, affecting pathophysiological processes through epigenetic changes that mediate gene-environment interactions. In this study, we explored two proposed models about the dynamic nature of DNA methylation in anxiety and depression: a stable change, in which DNA methylation accumulates over time as a function of the duration of clinical symptoms of anxiety and depression, or a flexible change, in which DNA methylation correlates with the acute severity of clinical symptoms. Symptom severity was assessed using clinical questionnaires for anxiety and depression (BDI-II, IDS-C, and HAM-A), and the current episode and the total lifetime symptom duration was obtained from patients' medical records. Peripheral blood DNA methylation levels were determined for the BDNF, COMT, and SLC6A4 genes. We found a significant negative correlation between COMT_1 amplicon methylation and acute symptom scores, with BDI-II (R(22) = 0.190, p = 0.033), IDS-C (R(22) = 0.199, p = 0.029), and HAM-A (R(22) = 0.231, p = 0.018) all showing a similar degree of correlation. Our results suggest that DNA methylation follows flexible dynamics, with methylation levels closely associated with acute clinical presentation rather than with the duration of anxiety and depression. These results provide important insights into the dynamic nature of DNA methylation in anxiety and affective disorders and contribute to our understanding of the complex interplay between stress, epigenetics, and individual phenotype.

The associations between DNA methylation and depression: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that epigenetic modification is vital in biological processes of depression. Findings from studies exploring the associations between DNA methylation and depression have been inconsistent.

METHODS

A systematical search of EMBASE, PubMed, Web of Science, and PsycINFO databases was conducted to include studies focusing on the associations between DNA methylation and depression (up to November 1st 2021) according to PRISMA guidelines with registration in PROSPERO (CRD42021288664).

RESULTS

A total of 47 studies met inclusion criteria and 31 studies were included in the meta-analysis. This meta-analysis found that genes hypermethylation, including BDNF (OR: 1.15, 95%CI: 1.01-1.32, I² = 90 %), and NR3C1 (OR: 1.43, 95%CI: 1.09-1.87, I² = 88 %) was associated with increased risk of depression. Significant association of SLC6A4 hypermethylation with depression was only found in the subgroup of using original data (OR: 1.09, 95%CI: 1.01-1.19, I² = 52 %). BDNF hypermethylation could increase the risk of depression only in the Asian population (OR: 1.18, 95%CI: 1.01-1.40, I² = 91 %), and significant associations of NR3C1 hypermethylation with depression were found in the group for depressive symptoms (OR: 1.34, 95%CI: 1.08-1.67, I² = 85 %), but not for depressive disorder (OR: 1.89, 95%CI: 0.54-6.55, I² = 94 %).

LIMITATIONS

More studies are needed to explore the factors that might influence the estimates owing to the contextual heterogeneity of the pooling of included studies.

CONCLUSIONS

It is noted that DNA hypermethylation, namely BDNF and NR3C1, is associated with increased risk of depression. The findings in this study could provide some material evidence for preventing and diagnosing of depression.

Brain-derived neurotrophic factor (BDNF) epigenomic modifications and brain-related phenotypes in humans: A systematic review

Epigenomic modifications of the brain-derived neurotrophic factor (BDNF) gene have been postulated to underlie the pathogenesis of neurodevelopmental, psychiatric, and neurological conditions. This systematic review summarizes current evidence investigating the association of BDNF epigenomic modifications (DNA methylation, non-coding RNA, histone modifications) with brain-related phenotypes in humans. A novel contribution is our creation of an open access web-based application, the BDNF DNA Methylation Map, to interactively visualize specific positions of CpG sites investigated across all studies for which relevant data were available. Our literature search of four databases through September 27, 2021 returned 1701 articles, of which 153 met inclusion criteria. Our review revealed exceptional heterogeneity in methodological approaches, hindering the identification of clear patterns of robust and/or replicated results. We summarize key findings and provide recommendations for future epigenomic research. The existing literature appears to remain in its infancy and requires additional rigorous research to fulfill its potential to explain BDNF-linked risk for brain-related conditions and improve our understanding of the molecular mechanisms underlying their pathogenesis.

Epigenetics in depression and gut-brain axis: A molecular crosstalk

Gut-brain axis is a dynamic, complex, and bidirectional communication network between the gut and brain. Changes in the microbiota-gut-brain axis are responsible for developing various metabolic, neurodegenerative, and neuropsychiatric disorders. According to clinical and preclinical findings, the gut microbiota is a significant regulator of the gut-brain axis. In addition to interacting with intestinal cells and the enteric nervous system, it has been discovered that microbes in the gut can modify the central nervous system through metabolic and neuroendocrine pathways. The metabolites of the gut microbiome can modulate a number of diseases by inducing epigenetic alteration through DNA methylation, histone modification, and non-coding RNA-associated gene silencing. Short-chain fatty acids, especially butyrate, are well-known histone deacetylases inhibitors. Similarly, other microbial metabolites such as folate, choline, and trimethylamine-N-oxide also regulate epigenetics mechanisms. Furthermore, various studies have revealed the potential role of microbiome dysbiosis and epigenetics in the pathophysiology of depression. Hence, in this review, we have highlighted the role of gut dysbiosis in epigenetic regulation, causal interaction between host epigenetic modification and the gut microbiome in depression and suggest microbiome and epigenome as a possible target for diagnosis, prevention, and treatment of depression.

BDNF and its signaling in cancer

PURPOSE

Brain-derived neurotrophic factor (BDNF) belongs to the family of neurotrophic factors that can potentially increase cancer cell growth, survival, proliferation, anoikis, and migration by tyrosine kinase receptors TrkB and the p75NTR death receptor. The activation of BDNF/TrkB pathways leads to several downstream signaling pathways, including PI3K/Akt, Jak/STAT, PLCγ, Ras-Raf-MEK-ERK, NF-kB, and transactivation of EGFR. The current review aimed to provide an overview of the role of BDNF and its signaling in cancer.

METHODS

We searched a major medical database, PubMed, to identify eligible studies for a narrative synthesis.

RESULTS

Pathological examinations demonstrate BDNF overexpression in human cancer, notably involving the prostate, lung, breast, and underlying tissues, associated with a higher death rate and poor prognosis. Therefore, measurement of BDNF, either for identifying the disease or predicting response to therapy, can be helpful in cancer patients. Expression profiling studies have recognized the role of microRNAs (miR) in modulating BDNF/TrkB pathways, such as miR-101, miR-107, miR-134, miR-147, miR-191, miR-200a/c, miR-204, miR-206, miR-210, miR-214, miR-382, miR-496, miR-497, miR-744, and miR-10a-5p, providing a potential biological mechanism by which targeted therapies may correlate with decreased BDNF expression in cancers. Clinical studies investigating the use of agents targeting BDNF receptors and related signaling pathways and interfering with the related oncogenic effect, including Entrectinib, Larotrectinib, Cabozantinib, Repotrectinib, Lestaurtinib, and Selitrectinib, are in progress.

CONCLUSION

The aberrant signaling of BDNF is implicated in various cancers. Well-designed clinical trials are needed to clarify the BDNF role in cancer progression and target it as a therapeutic method.

Acute Brain-Derived Neurotrophic Factor DNA Methylation Trajectories in Cerebrospinal Fluid and Associations With Outcomes Following Severe Traumatic Brain Injury in Adults

Background. Epigenetic biomarkers have the potential to explain outcome heterogeneity following traumatic brain injury (TBI) but are largely unexplored. Objective. This exploratory pilot study characterized brain-derived neurotrophic factor (BDNF) DNA methylation trajectories following severe TBI. Methods. Brain-derived neurotrophic factor DNA methylation trajectories in cerebrospinal fluid (CSF) over the first 5 days following severe TBI in 112 adults were examined in association with 3- and 12-month outcomes. Results. Group-based trajectory analysis revealed low and high DNA methylation groups at two BDNF cytosine-phosphate-guanine (CpG) targets that showed suggestive associations (P < .05) with outcomes. Membership in the high DNA methylation groups was associated with better outcomes after controlling for age, sex, and injury severity. Associations of age × trajectory group interactions with outcomes at a third CpG site revealed a pattern of the same or better outcomes with higher ages in the high DNA methylation group and worse outcomes with higher ages in the low DNA methylation group. Conclusions. Although no observed associations met the empirical significance threshold after correcting for multiple comparisons, suggestive associations of the main effect models were consistent in their direction of effect and were observed across two CpG sites and two outcome time points. Results suggest that higher acute CSF BDNF DNA methylation may promote recovery following severe TBI in adults, and this effect may be more robust with higher age. While the results require replication in larger and racially diverse independent samples, BDNF DNA methylation may serve as an early postinjury biomarker helping to explain outcome heterogeneity following TBI.

Structured Exercise in Cancer Survivors: Is it Enough for Neural, Mental Health and Well-being?

The purpose of this cross-sectional study was to explore physical activity, depression, fatigue, and quality of life (QOL), and their relationship to brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in cancer survivors enrolled in a structured exercise program. Participants were recruited into two groups: in-treatment (IT), currently receiving chemotherapy and/or radiotherapy, and out of treatment (OT), not undergoing therapy. Participants wore accelerometers for 7 days and completed cardiorespiratory fitness, muscular strength, and depression, fatigue, and QOL assessments. Circulating BDNF and NGF concentrations were obtained using enzyme-linked immunosorbent assays. Thirty-two participants (IT: n = 13, OT: n = 19) with an average age of 63 years and BMI of 27.5, spent 78% of their waking hours engaged in sedentary behavior outside of exercise training. Significant correlations were observed between light physical activity (LPA) outside of exercise training and QOL in IT (r = 0.626, p = 0.030), and fatigue in OT (r = 0.553, p = 0.021). Moderate to vigorous physical activity (MVPA) outside of exercise training significantly correlated with leg press strength (r = 0.700, p = 0.008) in IT, and cardiorespiratory fitness (r = 0.440, p = 0.013) when groups were combined. Concentrations of NGF did not differ between groups, and in IT, BDNF was positively related to LPA outside of training and was significantly lower (87 ± 28.5 pg/mL) than in OT (137 ± 54 pg/mL; p=0.010). While structured exercise programs should focus on improving cardiorespiratory fitness and muscular strength during exercise training, these programs should consider physical activity outside of training, if well-tolerated, to potentially further lower fatigue and improve QOL in cancer survivors.

The Importance of Epigenetics in Diagnostics and Treatment of Major Depressive Disorder

Recent studies imply that there is a tight association between epigenetics and a molecular mechanism of major depressive disorder (MDD). Epigenetic modifications, i.e., DNA methylation, post-translational histone modification and interference of microRNA (miRNA) or long non-coding RNA (lncRNA), are able to influence the severity of the disease and the outcome of the therapy. This article summarizes the most recent literature data on this topic, i.e., usage of histone deacetylases as therapeutic agents with an antidepressant effect and miRNAs or lncRNAs as markers of depression. Due to the noteworthy potential of the role of epigenetics in MDD diagnostics and therapy, we have gathered the most relevant data in this area.

New insights on brain-derived neurotrophic factor epigenetics: from depression to memory extinction

Advances in characterizing molecular profiles provide valuable insights and opportunities for deciphering the neuropathology of depression. Although abnormal brain-derived neurotrophic factor (BDNF) expression in depression has gained much support from preclinical and clinical research, how it mediates behavioral alterations in the depressed state remains largely obscure. Environmental factors contribute significantly to the onset of depression and produce robust epigenetic changes. Epigenetic regulation of BDNF, as one of the most characterized gene loci in epigenetics, has recently emerged as a target in research on memory and psychiatric disorders. Specifically, epigenetic alterations of BDNF exons are heavily involved in mediating memory functions and antidepressant effects. In this review, we discuss key research on stress-induced depression from both preclinical and clinical studies, which revealed that differential epigenetic regulation of specific BDNF exons is associated with depression pathophysiology. Considering that BDNF has a central role in depression, we argue that memory extinction, an adaptive response to fear exposure, is dependent on BDNF modulation and holds promise as a prospective target for alleviating or treating depression and anxiety disorders.

Methylation of WT1, CA10 in peripheral blood leukocyte is associated with breast cancer risk: a case-control study

Background

Studies have shown that abnormal changes of specific-gene DNA methylation in leukocytes may be associated with an elevated risk of cancer. However, associations between the methylation of the zinc-related genes, WT1 and CA10, and breast cancer risk remain unknown.

Methods

The methylation of WT1 and CA10 was analyzed by methylation-sensitive high-resolution-melting (MS-HRM) in a case-control study with female subjects (N = 959). Logistic regression was used to analyze the associations, and propensity score (PS) method was used to adjust confounders.

Results

The results showed that WT1 hypermethylation was associated with an increased risk of breast cancer, with an odds ratio (OR) of 3.07 [95% confidence interval (CI): 1.67–5.64, P < 0.01]. Subgroup analyses showed that WT1 hypermethylation was specifically associated with an elevated risk of luminal A subtype (OR = 2.62, 95% CI: 1.11–6.20, P = 0.03) and luminal B subtype (OR = 3.23, 95% CI: 1.34–7.80, P = 0.01). CA10 hypermethylation was associated with an increased risk of luminal B subtype (OR = 1.80, 95% CI: 1.09–2.98, P = 0.02).

Conclusion

The results of the present study suggest that the hypermethylation of WT1 methylation in leukocytes is significantly associated with an increased risk of breast cancer. The hypermethylation of WT1 is associated with an increased risk of luminal subtypes of breast cancer, and the hypermethylation of CA10 is associated with an increased risk of luminal B subtype of breast cancer.

MicroRNA-147 targets BDNF to inhibit cell proliferation, migration and invasion in non-small cell lung cancer

Lung cancer is one of the most common cancers that threaten human life and health. Recently, microRNAs (miRNAs) have been shown to play a unique role in many malignancies. Although the dysregulation of miR-147 has been detected in non-small cell lung cancer (NSCLC), the biological function of miR-147 is still unknown in NSCLC. The expression of miR-147 was observed by real-time quantitative polymerase chain reaction (RT-qPCR). Methyl thiazolyl tetrazolium (MTT) and Transwell assays were used to investigate the function of miR-147 in NSCLC. Target genes of miR-147 were verified using dual luciferase reporter assay. Western blot analysis was used to explore the PI3K/AKT pathway. The expression of miR-147 was decreased in NSCLC tissues, which was associated with poor prognosis in NSCLC patients. Furthermore, overexpression of miR-147 inhibited the viability and metastasis of NSCLC cells. In addition, miR-147 inhibited epithelial-mesenchymal transition (EMT) and inactivated the PI3K/AKT pathway in NSCLC. Furthermore, miR-147 directly targets brain-derived neurotrophic factor (BDNF) and negatively regulates BDNF expression in NSCLC. Upregulation of BDNF attenuated the inhibitory effect of miR-147 in NSCLC. In conclusion, miR-147 inhibits cell proliferation, migration and invasion in NSCLC through suppressing BDNF expression.

Interrelation Between Increased BDNF Gene Methylation and High Sociotropy, a Personality Vulnerability Factor in Cognitive Model of Depression

PURPOSE

It is suggested that increased methylation of the brain-derived neurotrophic factor (BDNF) gene is involved in the pathogenesis of depression, while sociotropy and autonomy are proposed as personality vulnerability factors in cognitive model of depression. We examined the interrelation between BDNF gene methylation and sociotropy or autonomy, with taking into account the previously reported deleterious effect of parental overprotection on sociotropy.

MATERIALS AND METHODS

The participants consisted of 90 healthy Japanese volunteers. Methylation levels of the BDNF gene in peripheral blood were quantified by bisulfite pyrosequencing. Sociotropy and autonomy were assessed by the Sociotropy-Autonomy Scale, and perceived parental protection was evaluated by the Parental Bonding Instrument.

RESULTS

In Pearson's correlation analysis, there was a positive correlation between methylation levels of the BDNF gene and sociotropy scores (p<0.05) but not autonomy scores, and a positive correlation between maternal protection scores and sociotropy scores (p<0.05). In structural equation modeling, two models were proposed; the first one is that hypermethylation of the BDNF gene and maternal overprotection independently contribute to high sociotropy, and the second one is that maternal overprotection contributes to high sociotropy which then leads to hypermethylation of the BDNF gene.

CONCLUSION

The present study suggests an interrelation between increased BDNF gene methylation and high sociotropy.

Predictors of Obesity among Gut Microbiota Biomarkers in African American Men with and without Diabetes

Gut microbiota and their biomarkers may be associated with obesity. This study evaluated associations of body mass index (BMI) with circulating microbiota biomarkers in African American men (AAM) (n = 75). The main outcomes included fecal microbial community structure (16S rRNA), gut permeability biomarkers (ELISA), and short-chain fatty acids (SCFAs, metabolome analysis). These outcomes were compared between obese and non-obese men, after adjusting for age. The results showed that lipopolysaccharide-binding protein (LBP), the ratio of LBP to CD14 (LBP/CD14), and SCFAs (propionic, butyric, isovaleric) were higher in obese (n = 41, age 58 years, BMI 36 kg/m²) versus non-obese (n = 34, age 55 years, BMI 26 kg/m²) men. BMI correlated positively with LBP, LBP/CD14 (p < 0.05 for both) and SCFAs (propionic, butyric, isovaleric, p < 0.01 for all). In the regression analysis, LBP, LBP/CD14, propionic and butyric acids were independent determinants of BMI. The study showed for the first time that selected microbiota biomarkers (LBP, LBP/CD14, propionic and butyric acids) together with several other relevant risks explained 39%–47% of BMI variability, emphasizing that factors other than microbiota-related biomarkers could be important. Further research is needed to provide clinical and mechanistic insight into microbiota biomarkers and their utility for diagnostic and therapeutic purposes.

Translational genomic research: the role of genetic polymorphisms in MBSR program among breast cancer survivors (MBSR[BC])

Genetic variations of breast cancer survivors (BCS) may contribute to level of residual symptoms, such as depression, stress, fatigue, and cognitive impairment. The objective of this study was to investigate whether particular single-nucleotide polymorphisms (SNPs) moderated symptom improvement resulting from the Mindfulness-Based Stress Reduction for Breast Cancer (MBSR[BC]) program. An overarching goal of personalized medicine is to identify individuals as risk for disease and tailor interventions based on genetic profiles of patients with diseases including cancer. BCS were recruited from Moffitt Cancer Center and University of South Florida's Breast Health Program and were randomized to either the 6-week MBSR(BC) program (n = 92) or Usual Care (n = 93). Measures of symptoms, demographic, and clinical history data were attained at baseline, 6 weeks, and 12 weeks. A total of 10 SNPs from eight genes known to be related to these symptoms were studied using genomic DNA extracted from blood. Our results were examined for effect sizes, consistency, and statistical significance (p < .05). Three SNPs (rs4680 in COMT, rs6314 in HTR2A, and rs429358 in APOE) emerged as having the strongest (though relatively weak) and most consistent effects in moderating the impact of the MBSR program on symptom outcomes. Although effects were generally weak, with only one effect withstanding multiple comparisons correction for statistical significance, this translational behavioral research may help start the identification of genetic profiles that moderate the impact of MBSR(BC). The ultimate goal of this study is the development of personalized treatment programs tailored to the genetic profile of each patient.

Abnormal Brain-Derived Neurotrophic Factor Exon IX Promoter Methylation, Protein, and mRNA Levels in Patients with Major Depressive Disorder

Brain-derived neurotrophic factor (BDNF) exon IX promoter methylation levels, serum BDNF protein levels, and serum mRNA levels were investigated in patients with major depressive disorder (MDD) and healthy controls. Over two years, 51 patients with MDD and 62 healthy controls were recruited. Peripheral blood was drawn from all participants to analyze the BDNF exon IX promoter methylation levels as well as serum BDNF protein and mRNA levels, at baseline and after four weeks of antidepressant treatment. Methylation sequential analysis showed that patients with MDD (n = 39) had a higher methylation level at CpG site 217 and lower methylation levels at CpG site 327 and CpG site 362. Drug responders (n = 25) had a higher methylation level at CpG site 24 and CpG site 324 than the non-responders (n = 11). Patients with MDD had a lower serum BDNF protein and mRNA levels than the healthy controls. In conclusion, these results showed that BDNF exon IX promoter methylation levels, serum BDNF protein level, and serum BDNF mRNA level could contribute to the pathophysiology of a major depressive disorder.

Is Brain-Derived Neurotrophic Factor: A Common Link Between Neurodegenerative Disorders and Cancer?

BACKGROUND

Cancer is a common disease caused by the excessive proliferation of cells, and neurodegenerative diseases are the disorders caused due to the degeneration of neurons. Both can be considered as diseases caused by the dysregulation of cell cycle events. A recent data suggests that there is a strong inverse association between cancer and neurodegenerative disorders. There is indirect evidence to postulate Brain-derived Neurotrophic Factor (BDNF) as a potential molecular link in this association.

DISCUSSION

The BDNF levels are found to be downregulated in many neurodegenerative disorders and are found to be upregulated in various kinds of cancers. The lower level of BDNF in Alzheimer's and Parkinson's disease has been found to be related to cognitive and other neuropsychological impairments, whereas, its higher levels are associated with the tumour growth and metastasis and poor survival rate in the cancer patients.

CONCLUSION

In this review, we propose that variance in BDNF levels is critical in determining the course of cellular pathophysiology and the development of cancer or neurodegenerative disorder. We further propose that an alternative therapeutic strategy that can modulate BDNF expression, can rescue or prevent above said pathophysiological course. Larger studies that examine this link through animal studies are imperative to understand the putative biochemical and molecular link to wellness and disease.

Mindfulness-Based Stress Reduction on breast cancer symptoms: systematic review and meta-analysis

Mindfulness-Based Stress Reduction practices increase the capacity for concentration and attention, and these practices are particularly effective for people with breast cancer. To analyze the effects of the application of Mindfulness-Based Stress Reduction on breast cancer symptoms. Systematic review and meta-analysis were carried out. To find suitable studies, the PubMed/ MEDLINE database was searched using the keywords "breast cancer" and "Mindfulness-Based Stress Reduction". Studies included were published between 2013 and 2017, written in English and showed methodological quality through the PEDro scale (score greater than 3). They also presented empirical evidence, had an experimental study design (randomized or non-randomized), and had full text available. For the meta-analysis, we used a random-effects model, with standardized mean differences and 95% confidence intervals. Seven studies were included, one non-randomized and containing only an intervention group of Mindfulness-Based Stress Reduction, and six randomized including samples of two or three groups. The non-randomized study showed 6 points on the PEDro scale, the randomized studies of two groups 6 to 7 points and studies with three groups showed 7 points. In the meta-analysis of the two randomized studies, the results, although not significant, revealed a moderate effect for Mindfulness-Based Stress Reduction on the outcome of fatigue, with a mean difference of -0.42 (95%CI -0.92- -0.07; p=0.09). Mindfulness-Based Stress Reduction seems to be a promising alternative for treatment of this disease's symptoms.

microRNA-107 inhibits gastric cancer cell proliferation and metastasis by targeting PI3K/AKT pathway

The present study was aimed to investigate the effect of miR-107 transfection on gastric cancer cell growth. Results from qRT-PCR revealed that level of miR-107 in SGC-7901 and MKN1 cell lines was down-regulated in comparison to the normal cells, GES-1. CCK-8 assay revealed a significant reduction in the proliferation of SGC-7901 cells on transfection with miR-107. The tumor growth was very slow in the mice implanted with SGC-7901/miR-107 compared to those bearing SGC-7901/miR-NC. In SGC-7901 cells metastasis potential after miR-107 transfection was examined using wound-healing and Transwell invasion assays. The migration as well as invasion potential of SGC-7901 cells was significantly lower on transfection with miR-107. The activity of luciferase was reduced markedly in SGC-7901 cells co-transfected with miR-107 mimic compared to miR-NC. However, miR-107 mimic co-transfection did not affect the luciferase activity in SGC-7901 cells bearing mutant-type BDNF 3'UTR. Western blot assay showed that miR-107 overexpression causes inhibition of BDNF mRNA and protein expression in SGC-7901 cells. The CCK8 assay showed that pBDNF transfection prevented miR-107 mediated inhibition of SGC-7901 cell proliferation. miR-107 mimic transfection inhibited expression of BDNF and activation of PI3K (p-PI3K) and AKT (p-AKT) in SGC-7901 cells. In order to confirm whether activation of PI3K and AKT by miR-107 mimic involves inhibition of BDNF, the cells were co-transfected with si-BDNF. The results revealed that si-BDNF transfection led to inhibition of BDNF expression and PI3K and AKT activation in SGC-7901 cells. In summary, the present study demonstrates that miR-107 expression inhibits proliferation and metastasis in gastric cancer cells. Therefore, miR-107 acts as tumor inhibitor for gastric cancer through targeting BDNF expression. Thus miR-107 can be used for treatment of gastric cancer.

Antidepressant-Like Effects of Acupuncture-Insights From DNA Methylation and Histone Modifications of Brain-Derived Neurotrophic Factor

Sensitive and stable biomarkers that facilitate depression detection and monitor the antidepressant efficiency are currently unavailable. Thus, the objective is to investigate the potential of DNA methylation and histone modifications of brain-derived neurotrophic factor (BDNF) in monitoring severity and antidepressive effects of acupuncture. The depression rat model was imitated by social isolation and chronic unpredicted mild stress (CUMS). The expression of serum BDNF was detected by enzyme-linked immunosorbent assay (ELISA), the hippocampal BDNF, acetylation levels in histone H3 lysine 9 (acH3K9), and HDAC2 by Western blot, the hippocampal mRNA of BDNF by RT-polymerase chain reaction (PCR). The DNA methylation patterns of the promoter I of BDNF was detected by MS-PCR. We investigated that the expression of BDNF in serum and hippocampus were significantly downregulated compared with controls. The same trend was found in mRNA of BDNF. Notably, acupuncture reversed the downregulation of BDNF in serum and hippocampus and mRNA of BDNF compared with model group. Acupuncture reversed the CUMS-induced downregulation of hippocampal acH3K9. On the contrary, the CUMS-induced upregulation of hippocampal HDAC2 in model group was significantly reversed by acupuncture. Collectively, the antidepressant effect of acupuncture might be mediated by regulating the DNA methylation and histone modifications of BDNF, which may represent novel biomaker for detection of depression and monitoring severity and antidepressive effects.

miR-613 inhibits gastric cancer progression through repressing brain derived neurotrophic factor

MicroRNA (miR)-613 has been reported to function as a tumor suppressor in several types of cancer. However, the biological function and underlying mechanism in gastric cancer (GC) has remained elusive. Therefore, the aim of the present study was to assess the expression and biological role of miR-613 in GC tissues and cell lines. miR-613 expression was found to be downregulated in 38 GC tissue samples compared to that in their adjacent non-cancerous tissues, and low expression of miR-613 was associated with lymph node metastasis and advanced tumor-nodes-metastasis stage. A gain-of-function assay demonstrated that miR-613 overexpression reduced tumor cell proliferation, migration and invasion of SGC-7901 cells, as determined by MTT and Transwell assays. Furthermore, brain-derived neutrophic factor (BDNF) was identified as a direct target of miR-613 in GC cells by a luciferase reporter assay. BDNF expression was upregulated and inversely correlated with miR-613 levels in GC tissues. In addition, knockdown of BDNF expression mimicked the tumor suppressive effect of miR-613 in GC cells. In conclusion, these findings demonstrated that miR-613 functions as a tumor suppressor in GC by targeting BDNF. Thus, miR-613 is a potential therapeutic target for GC.

Therapeutic Potentials of BDNF/TrkB in Breast Cancer; Current Status and Perspectives

Brain-derived neurotrophic factor (BDNF) is a potent neurotrophic factor that has been shown to stimulate breast cancer cell growth and metastasis via tyrosine kinase receptors TrkA, TrkB, and the p75^NTR death receptor. The aberrant activation of BDNF/TrkB pathways can modulate several signaling pathways, including Akt/PI3K, Jak/STAT, NF-kB, UPAR/UPA, Wnt/β-catenin, and VEGF pathways as well as the ER receptor. Several microRNAs have been identified that are involved in the modulation of BDNF/TrkB pathways. These include miR-206, miR-204, MiR-200a/c, MiR-210, MiR-134, and MiR-191; and these may be of value as prognostic and predictive biomarkers for detecting patients at high risk of developing breast cancer. It has been also been demonstrated that a high expression of genes involved in the BDNF pathway in breast cancer is associated with poor clinical outcome and reduced survival of patients. Several approaches have been developed for targeting this pathway, for example TKr inhibitors (AZD6918, CEP-701) and RNA interference. The aim of the current review was to provide an overview of the role of BDNF/TrkB pathways in the pathogenesis of breast cancer and its value as a potential therapeutic target. J. Cell. Biochem. 118: 2502-2515, 2017. © 2017 Wiley Periodicals, Inc.

"Gestaltomics": Systems Biology Schemes for the Study of Neuropsychiatric Diseases

The integration of different sources of biological information about what defines a behavioral phenotype is difficult to unify in an entity that reflects the arithmetic sum of its individual parts. In this sense, the challenge of Systems Biology for understanding the “psychiatric phenotype” is to provide an improved vision of the shape of the phenotype as it is visualized by “Gestalt” psychology, whose fundamental axiom is that the observed phenotype (behavior or mental disorder) will be the result of the integrative composition of every part. Therefore, we propose the term “Gestaltomics” as a term from Systems Biology to integrate data coming from different sources of information (such as the genome, transcriptome, proteome, epigenome, metabolome, phenome, and microbiome). In addition to this biological complexity, the mind is integrated through multiple brain functions that receive and process complex information through channels and perception networks (i.e., sight, ear, smell, memory, and attention) that in turn are programmed by genes and influenced by environmental processes (epigenetic). Today, the approach of medical research in human diseases is to isolate one disease for study; however, the presence of an additional disease (co-morbidity) or more than one disease (multimorbidity) adds complexity to the study of these conditions. This review will present the challenge of integrating psychiatric disorders at different levels of information (Gestaltomics). The implications of increasing the level of complexity, for example, studying the co-morbidity with another disease such as cancer, will also be discussed.

DNA Methylation in Major Depressive Disorder

Epigenetic mechanisms regulate gene expression, influencing protein levels and ultimately shaping phenotypes during life. However, both stochastic epigenetic variations and environmental reprogramming of the epigenome might influence neurodevelopment and ageing, and this may contribute to the origins of mental ill-health. Studying the role of epigenetic mechanisms is challenging, as genotype-, tissue- and cell type-dependent epigenetic changes have to be taken into account, while the nature of mental disorders also poses significant challenges for linking them with biological profiles. In this chapter, we summarise the current evidence suggesting the role of DNA methylation as a key epigenetic mechanism in major depressive disorder.

Epigenetic Research in Neuropsychiatric Disorders: the "Tissue Issue"

PURPOSE OF REVIEW

Evidence has linked neuropsychiatric disorders with epigenetic marks as either a biomarker of disease, biomarker of exposure, or mechanism of disease processes. Neuropsychiatric epidemiologic studies using either target brain tissue or surrogate blood tissue each have methodological challenges and distinct advantages.

RECENT FINDINGS

Brain tissue studies are challenged by small sample sizes of cases and controls, incomplete phenotyping, post-mortem timing, and cellular heterogeneity, but the use of a primary disease relevant tissue is critical. Blood-based studies have access to much larger sample sizes and more replication opportunities, as well as the potential for longitudinal measurements, both prior to onset and during the course of treatments. Yet, blood studies also are challenged by cell-type heterogeneity, and many question the validity of using peripheral tissues as a brain biomarker. Emerging evidence suggests that these limitations to blood-based epigenetic studies are surmountable, but confirmation in target tissue remains important.

SUMMARY

Epigenetic mechanisms have the potential to help elucidate biology connecting experiential risk factors with neuropsychiatric disease manifestation. Cross-tissue studies as well as advanced epidemiologic methods should be employed to more effectively conduct neuropsychiatric epigenetic research.

Hsp90-binding immunophilin FKBP51 forms complexes with hTERT enhancing telomerase activity

FK506-binding proteins are members of the immunophilin family of proteins. Those immunophilins associated to the 90-kDa-heat-shock protein, Hsp90, have been proposed as potential modulators of signalling cascade factors chaperoned by Hsp90. FKBP51 and FKBP52 are the best characterized Hsp90-bound immunophilins first described associated to steroid-receptors. The reverse transcriptase subunit of telomerase, hTERT, is also an Hsp90 client-protein and is highly expressed in cancer cells, where it is required to compensate the loss of telomeric DNA after each successive cell division. Because FKBP51 is also a highly expressed protein in cancer tissues, we analyzed its potential association with hTERT·Hsp90 complexes and its possible biological role. In this study it is demonstrated that both immunophilins, FKBP51 and FKBP52, co-immunoprecipitate with hTERT. The Hsp90 inhibitor radicicol disrupts the heterocomplex and favors the partial cytoplasmic relocalization of hTERT in similar manner as the overexpression of the TPR-domain peptide of the immunophilin. While confocal microscopy images show that FKBP51 is primarily localized in mitochondria and hTERT is totally nuclear, upon the onset of oxidative stress, FKBP51 (but not FKBP52) becomes mostly nuclear colocalizing with hTERT, and longer exposure times to peroxide favors hTERT export to mitochondria. Importantly, telomerase activity of hTERT is significantly enhanced by FKBP51. These observations support the emerging role assigned to FKBP51 as antiapoptotic factor in cancer development and progression, and describe for the first time the potential role of this immunophilin favoring the clonal expansion by enhancing telomerase activity.

MicroRNA-107 inhibits tumor growth and metastasis by targeting the BDNF-mediated PI3K/AKT pathway in human non-small lung cancer

Abnormal expression of microRNA-107 (miR-107) was found in non-small cell lung cancer (NSCLC). However, little is known about its role and molecular mechanism in NSCLC progression and metastasis. Therefore, the aims of this study were to clarify the potential role of miR-107 and molecular mechanism in NSCLC progression and metastasis. Quantitative real-time polymerase chain reaction assay showed that miR-107 expression levels were significantly decreased in NSCLC tissue and cell lines. Low miR-107 levels in tumor tissue correlated with advanced TNM stage and lymph node metastasis. Function assays showed that overexpression of miR-107 suppressed cell proliferation, migration and invasion in A549 cells in vitro, and inhibited NSCLC tumor growth in vivo. Further mechanism assays suggested the brain-derived neurotrophic factor (BDNF) was identified as a target gene of miR-107 in NSCLC cells. In addition, BDNF expression was upregulated, and inversely correlated with miR-107 in NSCLC tissues. Enforced overexpression of BDNF effectively reversed the tumor suppressive functions of miR-107 on NSCLC proliferation, migration and invasion. miR-107 overexpression or downregulation of BDNF was able to inhibit activation of PI3K/AKT signaling pathway. Taken together, our findings present the first evidence that miR-107 could suppress NSCLC metastasis by targeting BDNF and indirectly regulating PI3K/AKT signaling pathway, which might lead to a potential therapeutic strategy focusing on miR-107 and BDNF for human NSCLC.

BDNF DNA methylation changes as a biomarker of psychiatric disorders: literature review and open access database analysis

Brain-derived neurotrophic factor (BDNF) plays an important role in nervous system development and function and it is well established that BDNF is involved in the pathogenesis of a wide range of psychiatric disorders. Recently, numerous studies have associated the DNA methylation level of BDNF promoters with certain psychiatric phenotypes. In this review, we summarize data from current literature as well as from our own analysis with respect to the correlation of BDNF methylation changes with psychiatric disorders and address questions about whether DNA methylation related to the BDNF can be useful as biomarker for specific neuropsychiatric disorders.

Comorbidity of depression with physical disorders: research and clinical implications

Depression is prevalent in patients with physical disorders, particularly in those with severe disorders such as cancer, stroke, and acute coronary syndrome. Depression has an adverse impact on the courses of these diseases that includes poor quality of life, more functional impairments, and a higher mortality rate. Patients with physical disorders are at higher risk of depression. This is particularly true for patients with genetic and epigenetic predictors, environmental vulnerabilities such as past depression, higher disability, and stressful life events. Such patients should be monitored closely. To appropriately manage depression in these patients, comprehensive and integrative care that includes antidepressant treatment (with considerations for adverse effects and drug interactions), treatment of the physical disorder, and collaborative care that consists of disease education, cognitive reframing, and modification of coping style should be provided. The objective of the present review was to present and summarize the prevalence, risk factors, clinical correlates, current pathophysiological aspects including genetics, and treatments for depression comorbid with physical disorders. In particular, we tried to focus on severe physical disorders with high mortality rates, such as cancer, stroke, and acute coronary syndrome, which are highly comorbid with depression. This review will enhance our current understanding of the association between depression and serious medical conditions, which will allow clinicians to develop more advanced and personalized treatment options for these patients in routine clinical practice.