Despite an increase in the number of molecular epidemiological studies conducted in recent years to evaluate the association between human papillomavirus (HPV) and the risk of breast carcinoma, these studies remain inconclusive. Here we aim to detect HPV DNA in various tissues from patients with breast carcinoma using the method of HPV capture combined with massive paralleled sequencing (MPS). To validate the confidence of our methods, 15 cervical cancer samples were tested by PCR and the new method. Results showed that there was 100% consistence between the two methods.DNA from peripheral blood, tumor tissue, adjacent lymph nodes and adjacent normal tissue were collected from seven malignant breast cancer patients, and HPV type 16 (HPV16) was detected in 1/7, 1/7, 1/7 and 1/7 of patients respectively. Peripheral blood, tumor tissue and adjacent normal tissue were also collected from two patients with benign breast tumor, and 1/2, 2/2 and 2/2 was detected to have HPV16 DNA respectively. MPS metrics including mapping ratio, coverage, depth and SNVs were provided to characterize HPV in samples. The average coverage was 69% and 61.2% for malignant and benign samples respectively. 126 SNVs were identified in all 9 samples. The maximum number of SNVs was located in the gene of E2 and E4 among all samples. Our study not only provided an efficient method to capture HPV DNA, but detected the SNVS, coverage, SNV type and depth. The finding has provided further clue of association between HPV16 and breast cancer.

LSH, a SNF2 family DNA helicase, is a key regulator of DNA methylation in mammals. How LSH facilitates DNA methylation is not well defined. While previous studies with mouse embryonic stem cells (mESc) and fibroblasts (MEFs) derived from Lsh knockout mice have revealed a role of Lsh in de novo DNA methylation by Dnmt3a/3b, here we report that LSH contributes to DNA methylation in various cell lines primarily by promoting DNA methylation by DNMT1. We show that loss of LSH has a much bigger effect in DNA methylation than loss of DNMT3A and DNMT3B. Mechanistically, we demonstrate that LSH interacts with UHRF1 but not DNMT1 and facilitates UHRF1 chromatin association and UHRF1-catalyzed histone H3 ubiquitination in an ATPase activity-dependent manner, which in turn promotes DNMT1 recruitment to replication fork and DNA methylation. Notably, UHRF1 also enhances LSH association with the replication fork. Thus, our study identifies LSH as an essential factor for DNA methylation by DNMT1 and provides novel insight into how a feed-forward loop between LSH and UHRF1 facilitates DNMT1-mediated maintenance of DNA methylation in chromatin.

Global DNA hypomethylation is a most common epigenetic alteration in cancer, but the mechanism remains elusive. Previous studies demonstrate that UHRF1 but not UHRF2 is required for mediating DNA maintenance methylation by DNMT1. Here we report unexpectedly a conserved function for UHRF1 and UHRF2: inhibiting de novo DNA methylation by functioning as E3 ligases promoting DNMT3A degradation. UHRF1/2 are frequently overexpressed in cancers and we present evidence that UHRF1/2 overexpression downregulates DNMT3A proteins and consequently leads to DNA hypomethylation. Abrogating this negative regulation on DNMT3A or overexpression of DNMT3A leads to increased DNA methylation and impaired tumor growth. We propose a working model that UHRF1/2 safeguards the fidelity of DNA methylation and suggests that UHRF1/2 overexpression is likely a causal factor for widespread DNA hypomethylation in cancer via suppressing DNMT3A.

In mammals it is unclear if UHRF1-mediated DNA maintenance methylation by DNMT1 is strictly dependent on histone H3K9 methylation. Here we have generated an Uhrf1 knockin (KI) mouse model that specifically abolishes the H3K9me2/3-binding activity of Uhrf1. The homozygous Uhrf1 KI mice are viable and fertile, and exhibit ∼10% reduction of DNA methylation in various tissues. The reduced DNA methylation occurs globally in the genome and does not restrict only to the H3K9me2/3 enriched repetitive sequences. In vitro UHRF1 binds with higher affinity to reconstituted nucleosome with hemi-methylated CpGs than that with H3K9me2/3, although it binds cooperatively to nucleosome with both modifications. We also show that the nucleosome positioning affects the binding of methylated DNA by UHRF1. Thus, while our study supports a role for H3K9 methylation in promoting DNA methylation, it demonstrates for the first time that DNA maintenance methylation in mammals is largely independent of H3K9 methylation.

Previous studies have implicated an essential role for UHRF1-mediated histone H3 ubiquitination in recruiting DNMT1 to replication sites for DNA maintenance methylation during S phase of the cell cycle. However, the regulatory mechanism on UHRF1-mediated histone ubiquitination is not clear. Here we present evidence that UHRF1 and USP7 oppositely control ubiquitination of histones H3 and H2B in S phase of the cell cycle and that DNMT1 binds both ubiquitinated H3 and H2B. USP7 knockout markedly increased the levels of ubiquitinated H3 and H2B in S phase, the association of DNMT1 with replication sites and importantly, led to a progressive increase of global DNA methylation shown with increased cell passages. Using DNMT3A/DNMT3B/USP7 triple knockout cells and various DNA methylation analyses, we demonstrated that USP7 knockout led to an overall elevation of DNA methylation levels. Mechanistic study demonstrated that USP7 suppresses DNMT1 recruitment and DNA methylation through its deubiquitinase activity and the interaction with DNMT1. Altogether our study provides evidence that USP7 is a negative regulator of global DNA methylation and that USP7 protects the genome from excessive DNA methylation by attenuating histone ubiquitination-dependent DNMT1 recruitment.

We evaluated the association between plasma levels of mac-2 binding protein (M2BP) with the risk of in-stent restenosis (ISR) after percutaneous coronary intervention (PCI).

Sepsis is a condition that is associated with high rates of mortality. It is characterized by serious systemic inflammatory responses induced by pathogenic invasion. Although microRNA-150 (miR-150) has been previously reported to be involved in the modulation of sepsis, the underlying molecular mechanism in sepsis remains poorly understood. In the present study, the human monocytic cell line THP-1 was treated with LPS to mimic sepsis in vitro, following which miR-150 and STAT1 expression were measured using reverse transcription-quantitative PCR or western blotting. Secretion of inflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) into the medium were measured by ELISA. The potential relationship between STAT1 and miR-150 was determined using dual-luciferase reporter and RNA immunoprecipitation assays. miR-150 expression was found to be was downregulated by LPS treatment in THP-1 cells in both dose- and time-dependent manners. LPS treatment also induced IL-1β, IL-6 and TNF-α secretion in a manner that could be inhibited by miR-150 overexpression and enhanced by transfection with the miR-150 inhibitor. miR-150 was revealed to directly target STAT1 by negatively regulating its expression. In addition, STAT1 expression was demonstrated to be upregulated by LPS treatment. STAT1 overexpression reversed the inhibitory effects of miR-150 overexpression on IL-1β, IL-6 and TNF-α secretion whilst STAT1 knockdown attenuated IL-1β, IL-6 and TNF-α secretion induced by miR-150 inhibitor transfection. In conclusion, the present study suggested that miR-150 regulates the inflammatory response in macrophages following LPS challenge by regulating the expression of STAT1.

Some research has suggested that miRNA-10a (miR-10a-5p) had an inhibitory function in proliferation and invasion of cancers. Whereas the role of miR-10a-5p in melanoma has not been fully explored. This study aims to confirm LIN28B as the targeted gene of miR-10a-5p which was explored in melanoma cells. In addition, upstream regulatory molecule of miR-10a-5p was also investigated in melanoma cells.

Circular RNAs (circRNAs) have been reported to exert critical functions in tumorigenesis and development. However, the underlying mechanism by which circRNAs regulate melanoma progression remain to be elucidated.