BCL2-associated Transcription Factor Research Articles

CircZFR promotes colorectal cancer progression via stabilizing BCLAF1 and regulating the miR-3127-5p/RTKN2 axis.

Aberrant expression of circular RNAs (circRNAs) is frequently linked to colorectal cancer (CRC). Here, we identified circZFR as a promising biomarker for CRC diagnosis and prognosis. CircZFR was upregulated in CRC tissues and serum exosomes and its level was linked to cancer incidence, advanced-stages, and metastasis. In both in vitro and in vivo settings, circZFR promoted the growth and spread while suppressing apoptosis of CRC. Exosomes with circZFR overexpression promoted the proliferation and migration of cocultured CRC cells. Mechanistically, epithelial splicing regulatory protein 1 (ESRP1) in CRC cells may enhance the production of circZFR. BCL2-associated transcription factor 1 (BCLAF1) bound to circZFR, which prevented its ubiquitinated degradation. Additionally, circZFR sponged miR-3127-5p to boost rhotekin 2 (RTKN2) expression. Our TCP1-CD-QDs nanocarrier was able to carry and deliver circZFR siRNA (si-circZFR) to the vasculature of CRC tissues and cells, which inhibited the growth of tumors in patient-derived xenograft (PDX) models. Taken together, our results show that circZFR is an oncogenic circRNA, which promotes the development and spread of CRC in a BCLAF1 and miR-3127-5p-dependent manner. CircZFR is a possible serum biopsy marker for the diagnosis and a desirable target for further treatment of CRC.

Identification of SRSF10 as a promising prognostic biomarker with functional significance among SRSFs for glioma

AimsThe serine/arginine-rich splicing factor (SRSF) protein family members are essential mediators of the alternative splicing (AS) regulatory network, which is tightly implicated in cancer progression. However, the expression, clinical correlation, immune infiltration, and prognostic value of SRSFs in gliomas remain unclear. Materials and methodsGlioma samples were extracted from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) datasets. Several databases, such as HPA, DAVID, UALCAN were used to comprehensively explore the roles of SRSFs. In addition, experimental validation of SRSF10 was also conducted. Key findingsHere, we found the expression alterations of the SRSF family in glioma samples using data from the TCGA and CGGA_325 datasets. Among the 12 genes, most were found to be closely associated with glioma clinical features, which linked to poor prognosis in glioma patients. Interestingly, survival analysis identified only SRSF10 as a potential independent risk prognostic biomarker for glioma patients. Immune analysis indicated that glioma patients with high SRSF10 expression may respond well to immunotherapies targeting immune checkpoint (ICP) genes. Finally, knocking down SRSF10 reduced glioma cell viability, induced G1 cell cycle arrest, and induced the exclusion of bcl-2-associated transcription factor 1 (BCLAF1) exon 5a. SignificanceOverall, this study uncovers the oncogenic roles of most SRSF family members in glioma, with the exception of SRSF5, while highlighting SRSF10 as a potential novel independent prognostic biomarker for glioma.

BCLAF1-induced HIF-1α accumulation under normoxia enhances PD-L1 treatment resistances via BCLAF1-CUL3 complex

Bcl-2-associated transcription factor-1 (BCLAF1), an apoptosis-regulating protein of paramount significance, orchestrates the progression of various malignancies. This study reveals increased BCLAF1 expression in hepatocellular carcinoma (HCC) patients, in whom elevated BCLAF1 levels are linked to escalated tumor grades and diminished survival rates. Moreover, novel BCLAF1 expression is particularly increased in HCC patients who were not sensitive to the combined treatment of atezolizumab and bevacizumab, but not in patients who had tumors that responded to the combined regimen. Notably, overexpression of BCLAF1 increases HCC cell proliferation in vitro and in vivo, while the conditioned medium derived from cells overexpressing BCLAF1 strikingly enhances the tube-formation capacity of human umbilical vein endothelial cells. Furthermore, compelling evidence demonstrates that BCLAF1 attenuates the expression of prolyl hydroxylase domain protein 2 (PHD2) and governs the stability of hypoxia-inducible factor-1α (HIF-1α) under normoxic conditions without exerting any influence on transcription, as determined by Western blot and RT‒qPCR analyses. Subsequently, employing coimmunoprecipitation and immunofluorescence, we validated the reciprocal interaction between BCLAF1 and Cullin 3 (CUL3), through which BCLAF1 actively upregulates the ubiquitination and degradation of PHD2. The Western blot and RT‒qPCR results suggests that programmed death ligand-1 (PD-L1) is one of the downstream responders to HIF-1α in HCC. Thus, we reveal the pivotal role of BCLAF1 in promoting PD-L1 transcription and, through binding to CUL3, in promoting the accumulation of HIF-1α under normoxic conditions, thereby facilitating the ubiquitination and degradation of PHD2.

Ginsenoside compound K induces mitochondrial apoptosis in human hepatoma cells through Bclaf1-mediated modulation of ERK signaling

ABSTRACT Compound K (CK) is the metabolite and final active ingredient of diol-type ginsenosides. In this study, we investigated the effect of CK on mitochondrial apoptosis in SMMC-7721 and BEL-7404 cells and the regulatory mechanism through in vitro and in vivo experiments. The results demonstrated that CK inhibited Hepatocellular carcinoma (HCC) cells proliferation and arrested the cells in G0/G1 phase. CK induces mitochondrial apoptosis in HCC cells and inhibited p-ERK expression. Bcl-2 associated transcription factor 1 (Bclaf1) was distributed in the nucleus and cytoplasm, and CK inhibited its expression. Treatment of a nude mouse xenograft model bearing SMMC-7721 cells with CK decreased the expression of Bclaf1, p-ERK, and Bcl-2 but increased that of Bax. In summary, ginsenoside CK downregulated Bclaf1 expression, inhibited the activation of the ERK pathway, and triggered mitochondrial apoptosis in HCC. These findings uncovered a potential therapeutic strategy leveraging the anti-tumor effects of CK against HCC.

New insights from Whole Genome Sequencing: BCLAF1 deletion as a structural variant that predisposes cells towards cellular transformation.

Cancer arises from a multi‑step cellular transformation process where some mutations may be inherited, while others are acquired during the process of malignant transformation. Aberrations in the BCL2 associated transcription factor1 (BCLAF1) gene have previously been identified in patients with cancer and the aim of the present study was to identify structural variants(SVs) and the effects of BCLAF1 gene silencing on cell transformation. Whole‑genome sequencing was performed on DNA isolated from tumour biopsies with a histologically confirmed diagnosis of oesophageal squamous cell carcinoma(OSCC). Paired‑end sequencing was performed on the IlluminaHiSeq2000, with 300bp reads. Reads were aligned to the Homo sapiens reference genome (NCBI37) using ELAND andCASAVA software. SVs reported from the alignment were collated with gene loci, using the variant effect predictor of Ensembl. The affected genes were subsequently cross‑checked against the Genetic Association Database for disease and cancer associations. BCLAF1 deletion was identified as a noteworthy SV that could be associated with OSCC. Transient small interfering RNA‑mediated knockdown of BCLAF1 resulted in the altered expression of several downstream genes, including downregulation of the proapoptotic genes Caspase‑3 and BAX and the DNA damage repair genes exonuclease1, ATR‑interacting protein and transcription regulator protein BACH1. BCLAF1 deficiency also attenuated P53 gene expression. Inhibition of BCLAF1 expression also resulted in increased colony formation. These results provide evidence that the abrogation of BCLAF1 expression results in the dysregulation of several cancer signalling pathways and abnormal cell proliferation.

Bcl-2-associated transcription factor 1 Ser290 phosphorylation mediates DNA damage response and regulates radiosensitivity in gastric cancer

BackgroundDNA damage response plays critical roles in tumor pathogenesis and radiotherapy resistance. Protein phosphorylation is a critical mechanism in regulation of DNA damage response; however, the key mediators for radiosensitivity in gastric cancer still needs further exploration.MethodsA quick label-free phosphoproteomics using high-resolution mass spectrometry and an open search approach was applied to paired tumor and adjacent tissues from five patients with gastric cancer. The dysregulated phosphoproteins were identified and their associated-pathways analyzed using Gene Set Enrichment Analysis (GSEA). The mostly regulated phosphoproteins and their potential functions were validated by the specific antibodies against the phosphorylation sites. Specific protein phosphorylation was further analyzed by functional and clinical approaches.Results832 gastric cancer-associated unique phosphorylated sites were identified, among which 25 were up- and 52 down-regulated. Markedly, the dysregulated phosphoproteins were primarily enriched in DNA-damage-response-associated pathways. Particularly, the phosphorylation of Bcl-2-associated transcription factor 1 (BCLAF1) at Ser290 was significantly upregulated in tumor. The upregulation of BCLAF1 Ser290 phosphorylation (pBCLAF1 (Ser290)) in tumor was confirmed by tissue microarray studies and further indicated in association with poor prognosis of gastric cancer patients. Eliminating the phosphorylation of BCLAF1 at Ser290 suppressed gastric cancer (GC) cell proliferation. Upregulation of pBCLAF1 (Ser290) was found in association with irradiation-induced γ-H2AX expression in the nucleus, leading to an increased DNA damage repair response, and a marked inhibition of irradiation-induced cancer cell apoptosis.ConclusionsThe phosphorylation of BCLAF1 at Ser290 is involved in the regulation of DNA damage response, indicating an important target for the resistance of radiotherapy.

Role of BCLAF‐1 in PD‐L1 stabilization in response to ionizing irradiation

Programmed cell death ligand 1 (PD‐L1) is a major immunosuppressive checkpoint protein expressed by tumor cells to subvert anticancer immunity. Recent studies have shown that ionizing radiation (IR) upregulates the expression of PD‐L1 in tumor cells. However, whether an IR‐induced DNA damage response (DDR) directly regulates PD‐L1 expression and the functional significance of its upregulation are not fully understood. Here, we show that IR‐induced upregulation of PD‐L1 expression proceeds through both transcriptional and post‐translational mechanisms. Upregulated PD‐L1 was predominantly present on the cell membrane, resulting in T‐cell apoptosis in a co‐culture system. Using mass spectrometry, we identified PD‐L1 interacting proteins and found that BCLAF1 (Bcl2 associated transcription factor 1) is an important regulator of PD‐L1 in response to IR. BCLAF1 depletion decreased PD‐L1 expression by promoting the ubiquitination of PD‐L1. In addition, we show that CMTM6 is upregulated in response to IR and participates in BCLAF1‐dependent PD‐L1 upregulation. Finally, we demonstrated that the ATM/BCLAF1/PD‐L1 axis regulated PD‐L1 stabilization in response to IR. Together, our findings reveal a novel regulatory mechanism of PD‐L1 expression in the DDR.

A Spic/BCLAF1 Complex Suppresses Pre-B Cell Receptor Signaling in Response to RAG-Mediated DNA Breaks

B cell development is carefully orchestrated to generate a diverse antibody repertoire while preventing malignant transformation. At early developmental stages, the pre-B cell receptor (pre-BCR) is an essential regulator of B cell maturation, coordinating both clonal expansion and immunoglobulin light chain gene (Igl) assembly. Igl gene rearrangement proceeds through V(D)J recombination, which requires the generation of DNA double-stranded breaks (DSBs) and the subsequent joining of two distant DNA segments. The DSBs necessary for Igl gene rearrangements are generated by the RAG1 and RAG2 proteins, which form the RAG endonuclease. Once RAG DSBs are generated, cells must be prevented from re-entering cell cycle where DSBs can be aberrantly repaired as deleterious translocations. Thus, temporal segregation of pre-BCR driven proliferation and Igl gene assembly is essential for normal maturation and prevention of errors that could lead to leukemic transformation. The pre-BCR signals through the SYK tyrosine kinase to both drive proliferation and initiate Igl gene rearrangement. Unopposed activation of the pre-BCR, particularly increased SYK activity, blocks B cell development and supports leukemic transformation. Furthermore, pre-B leukemic blasts depend on SYK for proliferation and survival. Tight regulation of pre-BCR signaling is essential for enforcing normal maturation and suppressing leukemic transformation.We previously showed that pre-BCR signaling is inhibited by signals from RAG DSBs. Specifically, RAG DSBs trigger ATM-dependent induction of SPIC, an ETS family transcriptional repressor with significant homology to PU.1 and SPIB. SPIC inhibits expression of the SYK tyrosine kinase resulting in suppression of pre-BCR signaling, inhibition of pre-B cell proliferation, and limitation of additional RAG DSB generation. In order to determine the mechanism of SPIC-mediated gene regulation and to determine the role of SPIC in early B cell development, we compared SPIC and PU.1 binding throughout the genome in early B cells. Chromatin-immunoprecipitation followed by sequencing (ChIP-seq) identified shared binding sites for SPIC and PU.1 throughout the genome in pre-B cells suggesting that both transcription factors regulate a similar cohort of genes. Interestingly, binding of SPIC to the Syk promoter and the Igl(kappa) enhancer results in reduction of PU.1 binding at these sites and suppression of transcription of the respective genes. These results demonstrate that SPIC antagonizes PU.1 function to repress pre-BCR signaling in early B cells.SPIC shares a DNA binding domain motif with the other ETS-family transcription factors, PU.1 and SPIB, but has a unique transactivation domain, which could recruit transcriptional repressors to gene regulatory regions. To determine the unique binding partners of SPIC and PU.1, we generated pre-B cells expressing tetracycline-inducible FLAG-SPIC and FLAG-PU.1. The tagged proteins were purified from nuclei using tandem affinity purification. Mass spectrometry of the precipitated samples identified BCLAF1 (Bcl2 associated transcription factor 1) as a unique SPIC interactor. In contrast, IRF4 binds to PU.1 but not to SPIC. In pre-B cells, BCLAF1 binds to regulatory regions of a similar set of genes as SPIC. Consistent with this, BCLAF1 binds to the Syk promoter only in cells with RAG DSBs, which correlates with binding of SPIC and loss of PU.1 at this site. RNAi-mediated knockdown of BCLAF1 results in increased Syk mRNA expression. However, loss of BCLAF1 does not affect SPIC occupancy at the Syk promoter. Thus, SPIC binds DNA but only represses transcription if BCLAF1 is also recruited. Collectively, our findings reveal that, in response to RAG DSBs, SPIC and BCLAF1 cooperate to antagonize PU.1 function and regulate expression of a broad genetic program that modulates pre-BCR signaling to enforce normal B cell maturation. DisclosuresNo relevant conflicts of interest to declare.

The long noncoding RNA lncCIRBIL disrupts the nuclear translocation of Bclaf1 alleviating cardiac ischemia\u2013reperfusion injury

Cardiac ischemia–reperfusion (I/R) injury is a pathological process resulting in cardiomyocyte death. The present study aims to evaluate the role of the long noncoding RNA Cardiac Injury-Related Bclaf1-Inhibiting LncRNA (lncCIRBIL) on cardiac I/R injury and delineate its mechanism of action. The level of lncCIRBIL is reduced in I/R hearts. Cardiomyocyte-specific transgenic overexpression of lncCIRBIL reduces infarct area following I/R injury. Knockout of lncCIRBIL in mice exacerbates cardiac I/R injury. Qualitatively, the same results are observed in vitro. LncCIRBIL directly binds to BCL2-associated transcription factor 1 (Bclaf1), to inhibit its nuclear translocation. Cardiomyocyte-specific transgenic overexpression of Bclaf1 worsens, while partial knockout of Bclaf1 mitigates cardiac I/R injury. Meanwhile, partial knockout of Bclaf1 abrogates the detrimental effects of lncCIRBIL knockout on cardiac I/R injury. Collectively, the protective effect of lncCIRBIL on I/R injury is accomplished by inhibiting the nuclear translocation of Bclaf1. LncCIRBIL and Bclaf1 are potential therapeutic targets for ischemic cardiac disease.

BCLAF1 induces cisplatin resistance in lung cancer cells.

Treatment for non-small cell lung cancer (NSCLC) remains challenging due to frequent recurrence and the development of resistance to platinum-based chemotherapy. The mechanism underlying NSCLC chemoresistance remains unclear. The present study aimed to investigate the mechanism of cisplatin resistance in NSCLC cells and it found that the expression of Bcl-2-associated transcription factor 1 (BCLAF1) was higher in the A549 cell line with cisplatin resistance (A549/DDP) by western blotting and reverse-transcription quantitative PCR, suggesting that elevated BCLAF1 expression is associated with acquired cisplatin resistance in A549 cells. BCLAF1 was found to promote DNA damage repair in A549/DDP cells by regulating γH2A histone family member X foci formation by immunofluorescence and western blotting. BCLAF1 was also demonstrated to regulate ubiquitin-specific peptidase 22 mRNA expression in A549/DDP cells, in addition to regulating G1 phase arrest by targeting p21 expression. Taken together, these findings suggest that BCLAF1 mediates cisplatin resistance by regulating the repair of DNA damage and p21-mediated G1 phase arrest.

BCLAF1 promotes cell proliferation, invasion and drug-resistance though targeting lncRNA NEAT1 in hepatocellular carcinoma

AimsIn the present research, we aimed to investigate the effect of Bcl-2-associated transcription factor 1 (BCLAF1) on hepatocellular carcinoma and further explore the special molecular mechanism. Main methodsThe expression of BCLAF1 was analyzed in tumor tissues and different hepatocellular cancer cell lines by real-time RT-PCR and Western blot. Cell proliferation and invasion was explored using MTT and Transwell assay respectively. In addition, luciferase reporter assay was performed to determine the binding activity of BCLAF1 and Nuclear enrichment-rich transcription factor 1 (NEAT1) promoter. Finally, the IC50 for 5-Fluorouracil (5-Fu) was measured by MTT assay, and Western blot was used to determine the expression of P-glycoprotein (P-gp) and multidrug resistance protein1 (MRP1). Key findingThe result revealed that BCLAF1 was highly expressed in hepatocellular carcinoma tissues and cells. In addition, BCLAF1-siRNA inhibited the proliferation and invasion of hepatocellular carcinoma cells, and overexpression of BCLAF1 promoted proliferation and invasion. Furthermore, luciferase reporter assay demonstrated that BCLAF1 directly interact with lncNEAT1 promoter and improved NEAT1 expression, and BCLAF1 promoted proliferation and invasion through targeting lncRNA NEAT1. What's more, BCLAF1 promoted 5-Fu resistance and the expression of P-gp and MRP1 in hepatocellular carcinoma cells by targeting NEAT1. SignificanceThe results of the present study suggested that BCLAF1 might be a new gene related to proliferation and drug-resistance of hepatocellular carcinoma. In the future, the search for a deep and reasonable mechanism for the role of BCLAF1 will help us to understand its function more comprehensively, and finally find a new method for the treatment of human cancer.

Bclaf1 critically regulates the type I interferon response and is degraded by alphaherpesvirus US3.

Type I interferon response plays a prominent role against viral infection, which is frequently disrupted by viruses. Here, we report Bcl-2 associated transcription factor 1 (Bclaf1) is degraded during the alphaherpesvirus Pseudorabies virus (PRV) and Herpes simplex virus type 1 (HSV-1) infections through the viral protein US3. We further reveal that Bclaf1 functions critically in type I interferon signaling. Knockdown or knockout of Bclaf1 in cells significantly impairs interferon-α (IFNα) -mediated gene transcription and viral inhibition against US3 deficient PRV and HSV-1. Mechanistically, Bclaf1 maintains a mechanism allowing STAT1 and STAT2 to be efficiently phosphorylated in response to IFNα, and more importantly, facilitates IFN-stimulated gene factor 3 (ISGF3) binding with IFN-stimulated response elements (ISRE) for efficient gene transcription by directly interacting with ISRE and STAT2. Our studies establish the importance of Bclaf1 in IFNα-induced antiviral immunity and in the control of viral infections.

Tribbles Homolog 3 Involved in Radiation Response of Triple Negative Breast Cancer Cells by Regulating Notch1 Activation.

Breast cancer is the most common cancer for women in Taiwan and post-lumpectomy radiotherapy is one of the therapeutic strategies for this malignancy. Although the 10-year overall survival of breast cancer patients is greatly improved by radiotherapy, the locoregional recurrence is around 10% and triple negative breast cancers (TNBCs) are at a high risk for relapse. The aim of this paper is to understand the mechanisms of radioresistance in breast cancers which may facilitate the development of new treatments in sensitizing breast cancer toward radiation therapy. Tribbles homolog 3 (TRIB3) is a pseudokinase protein and known to function as a protein scaffold within cells. It has been reported that higher TRIB3 expression is a poor prognostic factor in breast cancer patients with radiotherapy. In this study, we investigate the involvement of TRIB3 in the radiation response of TNBC cells. We first found that the expression of TRIB3 and the activation of Notch1, as well as Notch1 target genes, increased in two radioresistant TNBC cells. Knockdown of TRIB3 in radioresistant MDA-MB-231 TNBC cells decreased Notch1 activation, as well as the CD24-CD44+ cancer stem cell population, and sensitized cells toward radiation treatment. The inhibitory effects of TRIB3 knockdown in self-renewal or radioresistance could be reversed by forced expression of the Notch intracellular domain. We also observed an inhibition in cell growth and accumulated cells in the G0/G1 phase in radioresistant MDA-MB-231 cells after knockdown of TRIB3. With immunoprecipitation and mass spectrometry analysis, we found that, BCL2-associated transcription factor 1 (BCLAF1), BCL2 interacting protein 1 (BNIP1), or DEAD-box helicase 5 (DDX5) were the possible TRIB3 interacting proteins and immunoprecipitation data also confirmed that these proteins interacted with TRIB3 in radioresistant MDA-MB-231 cells. In conclusion, the expression of TRIB3 in radioresistant TNBC cells participated in Notch1 activation and targeted TRIB3 expression may be a strategy to sensitize TNBC cells toward radiation therapy.

Bclaf1 Promotes Maintenance and Self-Renewal of Fetal Hematopoietic Stem Cells

Hematopoietic stem cells (HSC) persist throughout life by undergoing extensive self-renewal divisions while maintaining an undifferentiated state. The mechanisms that support HSC self-renewal change throughout the course of development as temporal changes in transcriptional regulators coordinate distinct genetic programs in fetal, post-natal and adult HSCs. These self-renewal programs are often ectopically activated in leukemia cells to drive neoplastic proliferation and high expression of HSC-associated genes predicts a poor prognosis in acute myelogenous leukemia (AML). In this regard, it was recently shown that expression of the transcriptional regulator BCLAF1 (Bcl2 associated transcription factor 1) is increased in AML blasts relative to normal precursor populations and suppression of BCLAF1 causes reduced proliferation and induction of differentiation to a dendritic cell fate. These findings raise the question of whether BCLAF1 may regulate normal as well as neoplastic self-renewal programs.We find that Bclaf1 is highly expressed in HSCs versus committed bone marrow populations consistent with a potential role for this gene in HSC functions. To test whether BCLAF1 regulates HSC development and hematopoiesis, we used germline loss of function mice. Bclaf1-/- mice succumb to pulmonary failure shortly after birth due to poor lung development, so we assessed prenatal hematopoiesis. Bclaf1-deficient mice had significantly reduced HSC and hematopoietic progenitor cell (HPC) frequencies and numbers despite normal fetal liver cellularity. To determine if Bclaf1 is required for HSC function during fetal development, we performed competitive reconstitution assays. Fetal liver cells from Bclaf1+/+ or Bclaf1-/- mice were transplanted along with wild-type competitor bone marrow cells into lethally irradiated recipient mice. Compared to recipients of Bclaf1+/+ fetal liver cells, recipients of Bclaf1-/- cells had a significantly lower percentage of donor-derived leukocytes at all time points after transplantation as well as reduced percentage of donor HSCs at 16 weeks post-transplant. Notably, all leukocyte populations (B cells, T cells, granulocytes and macrophages) from Bclaf1-/- donors were reduced consistent with an abnormality in HSC repopulating activity rather than a defect in a specific differentiation pathway. Consistent with these findings, Bclaf-deficient cells did not engraft in competitive transplants with limiting numbers of sorted fetal liver HSCs whereas sorted wild-type Bclaf1+/+ cells effectively reconstituted hematopoiesis in recipient mice. In addition, Vav-cre:Bclaf1flox/flox mice, which have selective deletion of Bclaf1 in hematopoietic cells, have reduced frequencies and numbers of fetal liver HSCs identical to the findings observed in germline Bclaf1-/- mice. These results show that loss of Bclaf1 leads to defective development and repopulating activity of fetal HSCs.Interestingly, when adult mice are successfully engrafted with Bclaf1-deficient HSCs, the donor HSCs suffer no additional functional impairment. Furthermore, in secondary transplant experiments Bclaf1-deficient HSCs maintain long-term repopulating activity. Thus, Bclaf1 may have distinct functions in fetal versus adult HSC self-renewal. Collectively, our findings reveal Bclaf1 is a novel regulator of fetal HSC function and suggest that it may have distinct functions in different developmental contexts. DisclosuresNo relevant conflicts of interest to declare.

Platelet-derived microparticles promote endothelial cell proliferation in hypertension via miR-142-3p.

Endothelial cells (ECs) are located at the interface between flowing blood and the vessel wall, and abnormal EC proliferation induced by pathologic environments plays an important role in vascular remodeling in hypertensive conditions. Exchanges of information between blood components and ECs are important for EC function. Hence, the present study sought to determine how platelets induce EC dysfunction under hypertensive conditions. EC proliferation was increased in renal hypertensive rats established by abdominal aortic coarctation compared with control rats and that elevated thrombin in plasma promoted platelet activation, which may induce the release of platelet-derived microparticles (PMPs). MicroRNA (MiR) array and qPCR revealed a higher level of miR-142-3p in platelets and PMPs. In vitro, PMPs delivered miR-142-3p into ECs and enhanced their proliferation via Bcl-2-associated transcription factor (BCLAF)1 and its downstream genes. These results indicate that PMPs deliver miR-142-3p from activated platelets into ECs and that miR-142-3p may play important roles in EC dysfunction in hypertensive conditions and may be a novel therapeutic target for maintaining EC homeostasis in hypertension.-Bao, H., Chen, Y.-X., Huang, K., Zhuang, F., Bao, M., Han, Y., Chen, X.-H., Shi, Q., Yao, Q.-P., Qi, Y.-X. Platelet-derived microparticles promote endothelial cell proliferation in hypertension via miR-142-3p.

The morphological changes and molecular biomarker responses in the liver of fluoride-exposed Bufo gargarizans larvae

The goal of the current study was to evaluate the negative influences of fluoride on liver of Bufo gargarizans larvae. B. gargarizans larvae were treated with 42.4mgF-/L for 0, 24, 48 and 72h at Gosner stage 37. The morphological changes and responses of molecular biomarkers involved in lipid metabolism, oxidative stress and apoptosis were examined in liver. Disappearance of cell boundaries, degeneration of hepatic parenchyma cells and significant increase in the number of melanomacrophage centres and the quantity of lipid droplets were found in the liver treated with 42.4mgF-/L for 72h. In addition, in the relative expression of acetyl CoA carboxylase 1 (ACC-1), fatty acid elongase 1 (FAE-1), sterol carrier protein 2 (SCP-2), and carnitine palmitoyltransferase-1 (CPT-1), decrease was observed after 24, 48 and 72h of 42.4mgF-/L exposure. Furthermore, the transcript levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were downregulated in tadpoles exposed for 24, 48 and 72h to 42.4mgF-/L, while the transcript level of heat shock protein 90 (HSP90) was upregulated at 42.4mgF-/L for 72h. Also, mRNA expression of Bcl-2-associated transcription factor 1(BCLAF1) and thyroid hormone receptors (TRα and TRβ) was significantly upregulated in tadpoles treated with 42.4mgF-/L for 72h. Therefore, our results suggested that the liver injury induced by fluoride might result from disruption of lipid metabolism, oxidative damage and apoptosis.

Alignment of Mitotic Chromosomes in Human Cells Involves SR-Like Splicing Factors Btf and TRAP150.

Serine-arginine-rich (SR) or SR-like splicing factors interact with exon junction complex proteins during pre-mRNA processing to promote mRNA packaging into mature messenger ribonucleoproteins (mRNPs) and to dictate mRNA stability, nuclear export, and translation. The SR protein family is complex, and while many classical SR proteins have well-defined mRNA processing functions, those of other SR-like proteins is unclear. Here, we show that depletion of the homologous non-classical serine-arginine-rich (SR) splicing factors Bcl2-associated transcription factor (Btf or BCLAF) and thyroid hormone receptor-associated protein of 150 kDa (TRAP150) causes mitotic defects. We hypothesized that the depletion of these SR-like factors affects mitosis indirectly through an altered expression of mitotic checkpoint regulator transcripts. We observed an altered abundance of transcripts that encode mitotic regulators and mitotic chromosome misalignment defects following Btf and/or TRAP150 depletion. We propose that, in addition to their previously reported roles in maintaining mRNA distribution, Btf and TRAP150 control the abundance of transcripts encoding mitotic regulators, thereby affecting mitotic progression in human cells.

MiR-194-5p/BCLAF1 deregulation in AML tumorigenesis

Deregulation of epigenetic mechanisms, including microRNA, contributes to leukemogenesis and drug resistance by interfering with cancer-specific molecular pathways. Here, we show that the balance between miR-194-5p and its newly discovered target BCL2-associated transcription factor 1 (BCLAF1) regulates differentiation and survival of normal hematopoietic progenitors. In acute myeloid leukemias this balance is perturbed, locking cells into an immature, potentially ‘immortal’ state. Enhanced expression of miR-194-5p by treatment with the histone deacetylase inhibitor SAHA or by exogenous miR-194-5p expression re-sensitizes cells to differentiation and apoptosis by inducing BCLAF1 to shuttle between nucleus and cytosol. miR-194-5p/BCLAF1 balance was found commonly deregulated in 60 primary acute myeloid leukemia patients and was largely restored by ex vivo SAHA treatment. Our findings link treatment responsiveness to re-instatement of miR-194-5p/BCLAF1 balance.

Upregulated SMYD3 promotes bladder cancer progression by targeting BCLAF1 and activating autophagy

The recent discovery of a large number of histone methyltransferases reveals important roles of these enzymes in regulating tumor development and progression. SMYD3, a histone methyltransferase, is associated with poor prognosis of patients with prostate and gastric cancer. In the study, we attempted to investigate its putative oncogenic role on bladder cancer. Here, we report that SMYD3 frequently amplified in bladder cancer is correlated with bladder cancer progression and poor prognosis. Overexpression of SMYD3 promotes bladder cancer cell proliferation and invasion, whereas SMYD3 knockdown inhibits cancer cell growth and invasion. Mechanically, SMYD3 positively regulates the expression of BCL2-associated transcription factor 1 (BCLAF1). SMYD3 physically interacts with the promoter of BCLAF1 and upregulates its expression by accumulating di- and trimethylation of H3K4 at the BCLAF1 locus. We further show that SMYD3 overexpression in bladder cancer cells promotes autophagy activation, whereas BCLAF1 depletion inhibits SMYD3-induced autophagy. Finally, we demonstrate that SMYD3 promotes bladder cancer progression, at least in part by increasing BCLAF1 expression and activating autophagy. Our results establish a function for SMYD3 in autophagy activation and bladder cancer progression and suggest its candidacy as a new prognostic biomarker and target for clinical management of bladder cancer.

The expression and prognostic significance of bcl-2-associated transcription factor 1 in rectal cancer following neoadjuvant therapy.

bcl-2-associated transcription factor 1 (BCLAF1) is a nuclear protein that binds to bcl-related proteins and can induce apoptosis and autophagy. The aim of this study was to investigate the expression of BCLAF1 in a series of rectal cancers following neoadjuvant therapy. Immunohistochemistry was performed on a post-neoadjuvant therapy rectal cancer tissue microarray. It contained rectal cancers (n = 248), lymph node metastases (n = 76), and non-neoplastic rectal mucosal samples (n = 73). A monoclonal antibody against BCLAF1 that we have developed was used. Non-neoplastic rectal epithelium showed nuclear localization of BCLAF1 in both crypt and surface epithelial cells, whereas rectal cancers showed both nuclear and cytoplasmic BCLAF1 expression. Most rectal cancers showed moderate or strong nuclear immunoreactivity, but showed weak cytoplasmic immunoreactivity. Cytoplasmic BCLAF1 expression was increased in primary rectal cancers as compared with non-neoplastic rectal mucosa (P = 0.008). Negative and weak nuclear BCLAF1 expression was associated with a poor prognosis [hazard ratio (HR) 0.502, 95% confidence interval (CI) 0.269-0.939, χ(2) = 4.876, P = 0.027]. Nuclear BCLAF1 expression was independently prognostic in a multivariate model (HR 0.431, 95% CI 0.221-0.840, P = 0.013). This study has shown that both cytoplasmic BCLAF1 expression and nuclear BCLAF1 expression are increased in post-neoadjuvant therapy rectal cancer, and that negative and weak nuclear BCLAF1 expression are independently associated with a poor prognosis.