Clinicopathological-genetic features of congenital myasthenic syndrome from a Chinese neuromuscular centre.

Congenital myasthenic syndrome (CMS) encompasses a heterogeneous group of inherited disorders affecting nerve transmission across the neuromuscular junction. The aim of this study was to characterize the clinical, physiological, pathohistological and genetic features of nine unrelated Chinese patients with CMS from a single neuromuscular centre. A total of nine patients aged from neonates to 34 years were enrolled who exhibited initial symptoms. Physical examinations revealed that all patients exhibited muscle weakness. Muscle biopsies demonstrated multiple myopathological changes, including increased fibre size variation, myofibrillar network disarray, necrosis, myofiber grouping, regeneration, fibre atrophy and angular fibres. Genetic testing revealed six different mutated genes, including AGRN (2/9), CHRNE (1/9), GFPT1 (1/9), GMPPB (1/9), PLEC (3/9) and SCN4A (1/9). In addition, patients exhibited differential responses to pharmacological treatment. Prompt utilization of genetic testing will identify novel variants and expand our understanding of the phenotype of this rare syndrome. Our findings contribute to the clinical, pathohistological and genetic spectrum of congenital myasthenic syndrome in China.

Montelukast, cysteinyl leukotriene receptor 1 antagonist, inhibits cardiac fibrosis by activating APJ.

Montelukast, cysteinyl leukotriene receptor 1 (CysLT1R) antagonist, is used clinically for patients with asthma, chronic obstructive pulmonary diseases (COPD), and allergic rhinitis. It has been reported that CysLT1R antagonists could reduce the risks of cardiovascular diseases in animal studies. Cardiac fibrosis is one of the major causes of heart failure. But little is known about the role of Montelukast in cardiac fibrosis and its underlying mechanism. In transverse aortic constriction (TAC) mice, Montelukast improved cardiac pumping function and inhibited cardiac fibrosis by down-regulation of the proteins related to the fibrosis, such as connective tissue growth factor (CTGF), Transforming Growth Factor ß (TGF-ß), and Alpha-smooth muscle actin (α-SMA). Montelukast reduced cell proliferation and collagen production in neonatal cardiac fibroblasts (CFs) with the pretreatment of 20% serum, while down-regulating the expression of TGF-ß, CTGF and α-SMA. Molecules docking methods estimated a high affinity of Montelukast to Apelin receptor (APJ) and an effective chemical structure for Montelukast binding APJ. In Chinese hamster ovary (CHO) cells with stable overexpressing APJ, Montelukast inhibited forskolin (1 µM)-mediated cyclic adenosine monophosphate (cAMP) production and extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation, while these effects were reversed by pertussis toxin (PTX) pretreatment. APJ silence disrupted the effects of Montelukast in CFs pretreatment by serum 20%. So we concluded that Montelukast inhibited cardiac fibrosis due presumably to the coupling to the APJ-mediated Gi signaling pathway, which may be a promising therapeutic target for cardiac fibrosis.

Findings of limb-girdle muscular dystrophy R7 telethonin-related patients from a Chinese neuromuscular center.

Limb-girdle muscular dystrophy (LGMD) is a group of clinically and genetically heterogeneous neuromuscular disorders. LGMD-R7, which is caused by telethonin gene (TCAP) mutations, is one of the rarest forms of LGMD, and only a small number of LGMD-R7 cases have been described and mostly include patients from Brazil. A total of two LGMD-R7 patients were enrolled at a Chinese neuromuscular center. Demographic and clinical data were collected. Laboratory investigations and electromyography were performed. Routine and immunohistochemistry staining of muscle specimens was performed, and a next-generation sequencing panel array for genes associated with hereditary neuromuscular disorders was used for analysis. The patients exhibited predominant muscle weakness. Electromyography revealed myopathic changes. The muscle biopsy showed myopathic features, such as increased fiber size variation, muscle fiber atrophy and regeneration, slight hyperplasia of the connective tissue, and disarray of the myofibrillar network. Two patients were confirmed to have mutations in the open reading frame of TCAP by next-generation sequencing. One patient had compound heterozygous mutations, and the other patient harbored a novel homozygous mutation. Western blotting analysis of the skeletal muscle lysate confirmed the absence of telethonin in the patients. We described two LGMD-R7 patients presenting a classical LGMD phenotype and a novel homozygous TCAP mutation. Our research expands the spectrum of LGMD-R7 due to TCAP mutations based on patients from a Chinese neuromuscular center.

Accurate identification and surgical correction of type IIb uterine malformation using synchronized hysteroscopy and laparoscopy.

OBJECTIVE: To introduce an effective approach for accurate identification and treatment of type IIb uterine malformation using synchronized hysteroscopy and laparoscopy. DESIGN: Step-by-step video explanation of the surgical procedure with still pictures and surgical video clips to demonstrate the detailed technique. The patient provided written informed consent for video and data collection for research purposes. The study was approved by the local ethics committee of Shengjing Hospital of China Medical University. SETTING: Academic medical center. PATIENT(S): A 32-year-old young woman diagnosed with a right unicornuate uterus with a left rudimentary horn, with a 2-year history of dysmenorrhea. INTERVENTION(S): First, the patient was diagnosed with a unicornuate uterus with a rudimentary horn using ultrasonography and magnetic resonance imaging before the surgery. During surgery, synchronized hysteroscopy and laparoscopy coupled with a light test was performed to make a definite identification of the type IIb uterine malformation. During treatment of the type IIb uterine malformation, there were two key steps: resected the rudimentary horn and reserved more myometrial tissue to reduce the risk of uterine rupture in a subsequent pregnancy; and corrected the uterus to prevent future uterine prolapse. For the suture technique, suturing during resection was performed instead of suturing after complete resection to reduce the intraoperative bleeding as much as possible. Furthermore, tubal catheterization and hydrotubation under hysteroscopy monitoring were performed. MAIN OUTCOME MEASURE(S): Value and feasibility of synchronized hysteroscopic and laparoscopic identification and treatment of the type IIb uterine malformation. RESULT(S): The total operation time was 89 minutes. The postoperative pathological findings revealed that the endometrium was found in the rudimentary horn. No dysmenorrhea was found during follow-up. At 26 months after the operation, the patient became pregnant naturally. Cesarean section was performed at 36 weeks + 2 days owing to premature rupture of the membranes. CONCLUSION(S): For the accurate identification and management of a type IIb uterine malformation, synchronized hysteroscopy and laparoscopy is an effective and feasible method.

A Systematic Review and Meta-Analysis of the Prevalence of Congenital Myopathy.

Background: Congenital myopathy constitutes a heterogeneous group of orphan diseases that are mainly classified on the basis of muscle biopsy findings. This study aims to estimate the prevalence of congenital myopathy through a systematic review and meta-analysis of the literature. Methods: The PubMed, MEDLINE, Web of Science, and Cochrane Library databases were searched for original research articles published in English prior to July 30, 2021. The quality of the included studies was assessed by a checklist adapted from STrengthening the Reporting of OBservational studies in Epidemiology (STROBE). To derive the pooled epidemiological prevalence estimates, a meta-analysis was performed using the random effects model. Heterogeneity was assessed using the Cochrane Q statistic as well as the I 2 statistic. Results: A total of 11 studies were included in the systematic review and meta-analysis. Of the 11 studies included, 10 (90.9%) were considered medium-quality, one (9.1%) was considered low-quality, and no study was assessed as having a high overall quality. The pooled prevalence of congenital myopathy in the all-age population was 1.50 (95% CI, 0.93-2.06) per 100,000, while the prevalence in the child population was 2.73 (95% CI, 1.34-4.12) per 100,000. In the pediatric population, the prevalence among males was 2.92 (95% CI, -1.70 to 7.55) per 100,000, while the prevalence among females was 2.47 (95% CI, -1.67 to 6.61) per 100,000. The prevalence estimates of the all-age population per 100,000 were 0.20 (95% CI 0.10-0.35) for nemaline myopathy, 0.37 (95% CI 0.21-0.53) for core myopathy, 0.08 (95% CI -0.01 to 0.18) for centronuclear myopathy, 0.23 (95% CI 0.04-0.42) for congenital fiber-type disproportion myopathy, and 0.34 (95% CI, 0.24-0.44) for unspecified congenital myopathies. In addition, the prevalence estimates of the pediatric population per 100,000 were 0.22 (95% CI 0.03-0.40) for nemaline myopathy, 0.46 (95% CI 0.03-0.90) for core myopathy, 0.44 (95% CI 0.03-0.84) for centronuclear myopathy, 0.25 (95% CI -0.05 to 0.54) for congenital fiber-type disproportion myopathy, and 2.63 (95% CI 1.64-3.62) for unspecified congenital myopathies. Conclusions: Accurate estimates of the prevalence of congenital myopathy are fundamental to supporting public health decision-making. The high heterogeneity and the lack of high-quality studies highlight the need to conduct higher-quality studies on orphan diseases.

Expanding the clinicopathological-genetic spectrum of GNE myopathy by a Chinese neuromuscular centre.

GNE myopathy is a heterogeneous group of ultrarare neuromuscular disorders caused by mutations in the GNE gene. An estimated prevalence of 1~21/1,000,000 leads to a deficiency of data and a lack of availability of samples to conduct clinical research on this neuromuscular disorder. Although GNE, which is the mutated gene responsible for the disease, is well known as the key enzyme in the biosynthesis pathway of sialic acid, the clinicopathological-genetic spectrum of GNE mutant patients is still unclear and expanding. This study presents ten unrelated patients with GNE myopathy, discovering five novel missense mutations. Clinical, electrophysiological, imaging, pathological and genetic data are presented in a retrospective manner. Interestingly, several patients in the cohort were found to have peripheral neuropathy and inflammatory cell infiltration in muscle biopsies, which have seldom been reported. This study, conducted by a neuromuscular centre in China, is the first attempt to highlight these abnormal clinicopathological features and associate them with genetic mutations in GNE myopathy.

Clinicopathological features of titinopathy from a Chinese neuromuscular center.

Titin, one of the largest proteins in humans, is a major component of muscle sarcomeres. Pathogenic variants in the titin gene (TTN) have been reported to cause a range of skeletal muscle diseases, collectively known as titinopathy. Titinopathy is a heterogeneous group of disabling diseases characterized by muscle weakness. In our study, we aimed to establish the clinicopathological-genetic spectrum of titinopathy from a single neuromuscular center. Three patients were diagnosed as having definite titinopathy, and additional three patients were diagnosed as having possible titinopathy according to the diagnostic criteria. All the patients showed initial symptoms from age one to 40 years. Physical examination revealed that five patients had muscle weakness, and that one patient experienced behavioral changes. Muscle biopsy specimens obtained from all six patients demonstrated multiple myopathological changes, including increased fiber size variation, muscle fiber hypertrophy or atrophy, formation of centralized cell nuclei, necklace cytoplasmic bodies, and formation of rimmed vacuoles and cores. Genetic testing revealed 11 different TTN alterations, including missense (6/11), nonsense (2/11), frameshift (2/11), and splicing (1/11) mutations. Our study provides further evidence that TTN mutations are more likely to be responsible for an increasing proportion of various myopathies, such as hereditary myopathy with early respiratory failure (HMERF), core myopathy, and distal myopathy with rimmed vacuoles, than currently recognized mutations. Our findings expand the clinical, pathohistological and genetic spectrum of titinopathy.

Hippocampal LASP1 ameliorates chronic stress-mediated behavioral responses in a mouse model of unpredictable chronic mild stress.

Substantial evidence has revealed that abnormalities in synaptic plasticity play important roles during the process of depression. LASP1 (LIM and SH3 domain protein 1), a member of actin-binding proteins, has been shown to be associated with the regulation of synaptic plasticity. However, the role of LASP1 in the regulation of mood is still unclear. Here, using an unpredictable chronic mild stress (UCMS) paradigm, we found that the mRNA and protein levels of LASP1 were decreased in the hippocampus of stressed mice and that UCMS-induced down-regulation of LASP1 was abolished by chronic administration of fluoxetine. Adenosine-associated virus-mediated hippocampal LASP1 overexpression alleviated the UCMS-induced behavioral results of forced swimming test and sucrose preference test in stressed mice. It also restored the dendritic spine density, elevated the levels of AKT (a serine/threonine protein kinase), phosphorylated-AKT, insulin-like growth factor 2, and postsynaptic density protein 95. These findings suggest that LASP1 alleviates UCMS-provoked behavioral defects, which may be mediated by an enhanced dendritic spine density and more activated AKT-dependent LASP1 signaling, pointing to the antidepressant role of LASP1.

BRCA1 affects the resistance and stemness of SKOV3-derived ovarian cancer stem cells by regulating autophagy.

Breast cancer 1 (BRCA1) and autophagy both play a significant role in drug resistance. However, little is known about the dynamic cross talk between BRCA1 and autophagy in the regulation of drug sensitivity. Here, we investigated the drug resistance-associated regulation of BRCA1 in epithelial ovarian cancer stem cells (EOCSCs). The results indicated that BRCA1 could regulate drug resistance in EOCSCs. Autophagy played a significant role in the stemness maintenance and was a key mechanism underlying the survival against chemotherapy in EOCSCs. Further investigation found that BRCA1 could regulate drug resistance of EOCSCs through autophagy. Meanwhile, changes in the level of autophagy provided feedback regarding the expression of BRCA1. Inhibition of autophagy activity could effectively reduce the resistance of EOCSCs caused by BRCA1. In addition, BRCA1 was able to regulate cellular apoptosis and cell cycle progression under the action of cisplatin through autophagy, indirectly affecting the drug sensitivity of EOCSCs. The present results highlight a novel relationship between BRCA1 and autophagy, which may provide insight into the etiology of BRCA1-associated ovarian cancer, and improve our understanding of resistance mechanisms in ovarian cancer.

Next-generation sequencing unravels extensive genetic alteration in recurrent ovarian cancer and unique genetic changes in drug-resistant recurrent ovarian cancer.

BACKGROUND: By using a high-throughput sequencing technique, we sought to delineate genetic alterations in recurrent ovarian cancer patients and further compare genetic changes in drug-resistant and -sensitive recurrent ovarian cancer patients. We also sought to study the specificity, sensitivity, and consistency of DNA biomarkers in liquid biopsy specimens and ovarian cancer tissue DNA. METHODS: Tumor tissue specimens and blood samples were obtained from pathologically proven recurrent ovarian cancer patients. Genomic DNA was extracted from tumor tissues, blood cells, ascites, and urine samples. The DNA Library was constructed and sequencing was performed using the Illumina HiSeq 4000 high-throughput sequencing platform. Bioinformatic analysis was done using the Torrent Suite software. RESULTS: Ten patients with pathologically proven drug-resistant recurrent ovarian cancer and 11 patients with sensitive recurrent ovarian cancer were included. The 5-year OS for drug-resistant recurrent ovarian cancer patients (44 ± 11.07 months, 95% CI: 231.24-53.66 months) was significantly lower than that of drug-sensitive recurrent ovarian cancer patients (58 ± 3.97 months; 95% CI: 50.05-65.59 months; p = 0.024) TP53 was the most frequently mutated gene in both drug-resistant (9/10, 90%) and drug-sensitive recurrent ovarian cancers (10/11, 91%). MYC and RB1 had the highest frequency of copy number variations (6/21, 29%) in recurrent ovarian cancers, followed by PIK3CA (3/21, 14%). BRCA2 N372H polymorphism was found in 40% (4/10) of drug-resistant recurrent ovarian cancer patients. The specificity, sensitivity, and consistency of TP53 and BRCA1 in circulating tumor-free DNA and tumor tissue DNA were 100%, 73.7%, 76.2% and 100%, 75%, 95.24%, respectively. CONCLUSION: We uncovered extensive genetic alterations in recurrent ovarian cancer and drug-resistant recurrent ovarian cancer exhibited unique genetic changes compared with recurrent ovarian cancer and drug-sensitive recurrent ovarian cancer. We further showed that high-throughput sequencing using liquid biopsy specimens could provide an effective, specific, and sensitive approach for detecting genetic alterations in ovarian cancer.

Autophagy is activated in the ovarian tissue of polycystic ovary syndrome.

The importance of autophagy in polycystic ovary syndrome (PCOS)-related metabolic disorders is increasingly being recognized, but few studies have investigated the role of autophagy in PCOS. Here, transmission electron microscopy demonstrated that autophagy was enhanced in the ovarian tissue from both humans and rats with PCOS. Consistent with this, ovarian granulosa cells from PCOS rats showed increases in the autophagy marker protein light chain 3B (LC3B), whereas levels of the autophagy substrate SQSTM1/p62 were decreased. In addition, the ratio of LC3-II/LC3-I was markedly elevated in human PCOS ovarian tissue compared with normal ovarian tissue. Real-time PCR arrays indicated that 7 and 34 autophagy-related genes were down- and up-regulated in human PCOS , Signal-Net, and regression analysis suggested that there are a wide range of interactions among these 41 genes, and a potential network based on EGFR, ERBB2, FOXO1, MAPK1, NFKB1, IGF1,TP53 and MAPK9 may be responsible for autophagy activation in PCOS. Systematic functional analysis of 41 differential autophagy-related genes indicated that these genes are highly involved in specific cellular processes such as response to stress and stimulus, and are linked to four significant pathways, including the insulin, ERBB, mTOR signaling pathways and protein processing in the endoplasmic reticulum. This study provides evidence for a potential role of autophagy disorders in PCOS in which autophagy may be an important molecular event in the pathogenesis of PCOS.

Comparative immunoprofiling of polymyositis and dermatomyositis muscles.

The morphological, immunohistochemical, and immunopathological analyses of muscle biopsy are essential for the diagnosis of idiopathic inflammatory myopathies (IIMs). However, they are also one of the most common causes of misdiagnosis. Although several diagnostic criteria have been proposed for the diagnosis of IIMs, misdiagnosis still remains common in clinical practice. The present study aims to characterize the inflammatory profile of IIMs, including the expression of MHC-I, MHC-II, MAC and infiltrating cells. We also investigated the sensitivity and specificity of MHC-I and MHC-II immunostaining for the diagnosis of IIMs. We found that the expression of MHC-I and MHC-II was both higher in IIMs than in non-inflammatory myopathies (NIMs). The distribution of MHC-I in IIMs is different from that of MHC-II. MHC-I is mainly located in the sarcoplasms, while MHC-II is located mostly on the sarcolemmas. Moreover, our findings suggest that MAC may be a potential marker to diagnose DM, and the combination of MHC-I and MHC-II immunostaining results in a higher sensitivity and specificity for IIM diagnosis, especially for DM. In addition, infiltrating cells in PM were mainly CD8+ cells, but we found in DM and NIMs they were primarily CD4+ cells, which is consistent with previous studies. Lastly, glucocorticoid treatment and disease duration have little effect on the MHC-I and MHC-II expression pattern. Our findings indicate that the immunostaining of inflammatory markers such as MHC-I, MHC-II, CD4, CD8, CD303 and MAC are of diagnostic value for IIMs regardless of the immunosuppression regime and disease duration.

Effect of the BRCA1-SIRT1-EGFR axis on cisplatin sensitivity in ovarian cancer.

There is accumulating evidence that breast cancer 1 (BRCA1), sirtuin 1 (SIRT1), and epidermal growth factor receptor (EGFR) help to modulate cisplatin cytotoxicity. The role of dynamic crosstalk among BRCA1, SIRT1, and EGFR in cisplatin sensitivity remains largely unknown. We found that BRCA1, SIRT1, and EGFR levels were increased in cisplatin-resistant ovarian cancers compared with those in cisplatin-sensitive ovarian cancers. Hypomethylation in the BRCA1 promoter was associated with BRCA1 activation, significantly elevated SIRT1 levels, decreased nicotinamide adenine dinucleotide (NAD)-mediated SIRT1 activity, and decreased EGFR levels. Treatment with 5 and 10 µg/ml cisplatin induced a gradual increase in BRCA1 and SIRT1 levels and a gradual decrease in NAD levels and NAD-mediated SIRT1 activity, whereas EGFR levels were increased or decreased by treatment with 5 or 10 µg/ml cisplatin, respectively. The overexpression of SIRT1 or the enhancement of SIRT1 activity synergistically enhanced the BRCA1-mediated effects on EGFR transcription. In contrast, the knockdown of SIRT1 or the inhibition of SIRT1 activity inhibited the BRCA1-mediated effects on EGFR transcription. BRCA1 regulates EGFR through a BRCA1-mediated balance between SIRT1 expression and activity. Those results improve our understanding of the basic molecular mechanism underlying BRCA1-related cisplatin resistance in ovarian cancer.

Incidence and clinical characteristics of unexpected uterine sarcoma after hysterectomy and myomectomy for uterine fibroids: a retrospective study of 10,248 cases.

BACKGROUND: Uterine fibroids often require a hysterectomy or myomectomy via laparotomy or laparoscopy. Morcellation is often necessary to perform a laparoscopic surgery. The objective of this study is to determine the incidence of unexpected uterine sarcomas (UUSs) after hysterectomy and myomectomy for uterine fibroids and to reduce the occurrence and avoid the morcellation of UUSs by analyzing their characteristics. METHODS: Women who had a hysterectomy or myomectomy for uterine fibroids in Shengjing Hospital of China Medical University between November 2008 and November 2014 were selected for the study, and their clinical characteristics were analyzed. RESULTS: During the period, 48 UUSs were found in 10,248 cases, and the overall incidence was 0.47%. There was no statistical difference (P=0.449) regarding the incidence (0.50% vs 0.33%) between 42 UUSs in 8,456 cases undergoing laparotomy and six UUSs in 1,792 cases undergoing laparoscopy. Most of the UUSs were stage I (89.58%), which occurred more commonly (56.25%) in women aged 40-49. Abnormal uterine bleeding (39.58%) was the main clinical manifestation. Rapidly growing pelvic masses (12.5%), rich blood flow signals (18.75%), and degeneration of uterine fibroids (18.75%) prompted by ultrasonography may suggest the possibility of UUSs. The margins of most UUSs (93.75%) were regular, which may cause UUSs to be misdiagnosed as uterine fibroids. Fifteen cases underwent magnetic resonance imaging examinations. Approximately 73.33% showed heterogeneous and hypointense signal intensity on T1-weighted images, and 80% showed intermediate-to-high signal intensity on T2-weighted images, with necrosis and hemorrhage in 40% of cases. After contrast administration, 80% presented early heterogeneous enhancement. CONCLUSION: The incidence of UUSs after hysterectomy and myomectomy for uterine fibroids was low, and their clinical characteristics are atypical. It is necessary and very critical to make a complete and cautious preoperative evaluation to reduce the occurrence and avoid the morcellation of UUSs.

Nicotinamide adenine dinucleotide (NAD) may affect DNA methyltransferase 1 through regulation of BRCA1 in ovarian cancer.

Nicotinamide adenine dinucleotide (NAD) is a crucial molecule of energy production and signal transduction processes that have been linked to ovarian cancer development. Notably, emerging evidence has led to considerable interest in the role of DNA methyltransferase 1 (DNMT1) in the initiation and progression of ovarian cancer. However, dynamic crosstalk between NAD and DNMT1 is poorly understood. Here, we show that DNMT1 levels are upregulated, along with increased NAD levels in non-BRCA1-mutated ovarian cancer cells. In contrast, DNMT1 levels are not affected by increasing NAD levels in BRCA1-mutated ovarian cancer cells. Mechanistically, BRCA1 inactivity-mediated loss of H3K9ac enrichment around the core promoter inhibits DNMT1 transcription. Consistent with this, BRCA1 levels correlate with DNMT1 levels (R = 0.534, R < 0.001) in human ovarian cancer specimens. Therefore, these results highlight a novel regulatory effect of NAD on DNMT1, and further correlate the physiological properties of NAD metabolism with DNMT1-mediated biological processes. All of this may improve our understanding of the basic molecular mechanism underlying NAD- and DNMT1-related ovarian cancer progression.

A novel crosstalk between BRCA1 and poly (ADP-ribose) polymerase 1 in breast cancer.

BRCA mutations are the main known hereditary factor for breast cancer. Notably, poly (ADP-ribose) polymerase 1 (PARP1) expression status plays a critical role in breast cancer progression and the clinical development of PARP1 inhibitors to treat BRCA-mutated breast cancer has advanced rapidly. However, dynamic crosstalk between BRCA1 and PARP1 remains largely unknown. Here, we showed that: (i) BRCA1 inactivation events (mutation, promoter methylation, or knockdown) were accompanied by increased PARP1 and nicotinamide adenine dinucleotide (NAD) levels, and a subsequent increase in NAD-dependent PARP1 activity in MDA-MB-231 and primary breast cancer cells; (ii) the overexpression of BRCA1 resulted in decreased PARP1 and NAD levels, and a subsequent impairment in NAD-dependent PARP1 activity in MDA-MB-231 and primary breast cancer cells; and (iii) intracellular NAD levels were largely responsible for regulating PARP1 activity in breast cancer cells, and NAD levels were positively correlated with PARP1 activity in human breast cancer specimens (R = 0.647, P < 0.001). Interestingly, the high efficiency of PARP1 triggered by BRCA1 inactivation may further inhibit BRCA1 transcription by NAD depletion. These results highlight a novel interaction between BRCA1 and PARP1, which may be beneficial for the dynamic balance between BRCA1 and PARP1-related biologic processes, especially for maintaining stable DNA repair ability. All of this may improve our understanding of the basic molecular mechanism underlying BRCA1- and PARP1-related breast cancer progression.

A novel crosstalk between BRCA1 and sirtuin 1 in ovarian cancer.

BRCA mutations are the main known hereditary factors for ovarian cancer. Notably, emerging evidence has led to considerable interest in the role of sirtuin 1 (SIRT1) in ovarian cancer development. However, dynamic crosstalk between BRCA1 and SIRT1 is poorly understood. Here, we showed that: (i) BRCA1 inactivation events (mutation, promoter methylation, or knockdown) were accompanied by decreased SIRT1 levels and increased nicotinamide adenine dinucleotide (NAD) levels and a subsequent increase in SIRT1 activity; (ii) overexpression of BRCA1 resulted in increased SIRT1 levels, an impairment in NAD synthesis, and a subsequent inhibition of SIRT1 activity; and (iii) intracellular NAD levels were largely responsible for regulating SIRT1 activity, and BRCA1 expression patterns correlated with SIRT1 levels and NAD levels correlated with SIRT1 activity in human ovarian cancer specimens. Interestingly, although BRCA1 inactivation events inhibited SIRT1 expression, they led to a substantial increase in NAD levels that enhanced NAD-related SIRT1 activity. This is a special BRCA1-mediated compensatory mechanism for the maintenance of SIRT1 function. Therefore, these results highlight a novel interaction between BRCA1 and SIRT1, which may be beneficial for the dynamic balance between BRCA1-related biologic processes and SIRT1-related energy metabolism and stress response.

Epigenetic repression of phosphatidylethanolamine N-methyltransferase (PEMT) in BRCA1-mutated breast cancer.

Phosphatidylethanolamine N-methyltransferase (PEMT) plays a critical role in breast cancer progression. However, the epigenetic mechanism regulating PEMT transcription remains largely unknown. Here, we show that the first promoter-specific transcript 1 is the major PEMT mRNA species, and methylation of the -132 site is a key regulatory element for the PEMT gene in BRCA1-mutated breast cancer. Mechanistically, hypermethylated -132 site-mediated loss of active histone marks H3K9ac and increase of repressive histone marks H3K9me enrichment synergistically inhibited PEMT transcription. Clinicopathological data indicated that a hypermethylated -132 site was associated with histological grade (P = 0.031) and estrogen receptor status (P = 0.004); univariate survival and multivariate analyses demonstrated that lymph node metastasis was an independent and reliable prognostic factor for BRCA1-mutated breast cancer patients. Our findings imply that genetic (e.g., BRCA1 mutation) and epigenetic mechanisms (e.g., DNA methylation and histone modifications) are jointly involved in the malignant progression of PEMT-related breast cancer.

Regulation of DNA methyltransferase 1 transcription in BRCA1-mutated breast cancer: a novel crosstalk between E2F1 motif hypermethylation and loss of histone H3 lysine 9 acetylation.

BACKGROUND: DNA methyltransferase 1 (DNMT1) plays a critical role in breast cancer progression. However, the epigenetic mechanism regulating DNMT1 expression remains largely unknown. METHODS: Epigenetic regulation of DNMT1 was assessed in 85 invasive ductal carcinomas from BRCA1 mutation carriers. Association between clinicopathological features and DNMT1 promoter methylation was determined using Fisher's exact test. Univariate analysis of survival was performed using the Kaplan-Meier method. Multivariate Cox regression analysis was performed to identify the independent prognostic factors for overall survival. RESULTS: Hypermethylated E2F transcription factor 1 (E2F1) motif is a key regulatory element for the DNMT1 gene in BRCA1-mutated breast cancer. Mechanistically, the abnormal E2F1 motif methylation-mediated loss of active histone H3 lysine 9 acetylation (H3K9ac) and transcription factor E2F1 enrichment synergistically inhibited the transcription of DNMT1. Clinicopathological data indicated that the hypermethylated E2F1 motif was associated with histological grade, lymph node, Ki67 and E-cadherin status; univariate survival and multivariate analyses demonstrated that lymph node metastasis was an independent and reliable prognostic factor for BRCA1-mutated breast cancer patients. CONCLUSIONS: Our findings imply that genetic (such as BRCA1 mutation) and epigenetic mechanisms (such as DNA methylation, histone modification, transcription factor binding) are jointly involved in the malignant progression of DNMT1-related breast cancer.

Poly (ADP-ribose) polymerase 1 transcriptional regulation: a novel crosstalk between histone modification H3K9ac and ETS1 motif hypomethylation in BRCA1-mutated ovarian cancer.

Poly (ADP-ribose) polymerase 1 (PARP1) plays a critical role in ovarian cancer progression. However, the epigenetic mechanism regulating PARP1 transcription remains largely unknown. Here, we show that the hypomethylated ETS1 motif is a key regulatory element for the PARP1 gene in BRCA1-mutated ovarian cancer. Mechanistically, the ETS1 motif hypomethylation-mediated increase of active histone marker H3K9ac and transcription factor ETS1 enrichment synergistically activates PARP1 transcription. Clinicopathological data indicate that a hypomethylated ETS1 motif was associated with high-grade tumors (P = 0.026) and pN1 (P = 0.002). Univariate survival analysis demonstrated an association between the hypomethylated ETS1 motif and an increased risk of death in BRCA1-mutated ovarian cancer patients. Our findings imply that the genetic (such as BRCA1 mutation) and epigenetic mechanisms (such as hypomethylated ETS1 motif, and histone modification H3K9ac and transcription factor ETS1 binding) are jointly involved in the malignant progression of PARP1-related ovarian cancer.