The kinase activity of the Ser/Thr kinase BUB1 promotes TGF-β signaling

BUB1 regulates non-homologous end joining pathway to mediate radioresistance in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer subtype often treated with radiotherapy (RT). Due to its intrinsic heterogeneity and lack of effective targets, it is crucial to identify novel molecular targets that would increase RT efficacy. Here we demonstrate the role of BUB1 (cell cycle Ser/Thr kinase) in TNBC radioresistance and offer a novel strategy to improve TNBC treatment.

METHODS

Gene expression analysis was performed to look at genes upregulated in TNBC patient samples compared to other subtypes. Cell proliferation and clonogenic survivals assays determined the IC50 of BUB1 inhibitor (BAY1816032) and radiation enhancement ratio (rER) with pharmacologic and genomic BUB1 inhibition. Mammary fat pad xenografts experiments were performed in CB17/SCID. The mechanism through which BUB1 inhibitor sensitizes TNBC cells to radiotherapy was delineated by γ-H2AX foci assays, BLRR, Immunoblotting, qPCR, CHX chase, and cell fractionation assays.

RESULTS

BUB1 is overexpressed in BC and its expression is considerably elevated in TNBC with poor survival outcomes. Pharmacological or genomic ablation of BUB1 sensitized multiple TNBC cell lines to cell killing by radiation, although breast epithelial cells showed no radiosensitization with BUB1 inhibition. Kinase function of BUB1 is mainly accountable for this radiosensitization phenotype. BUB1 ablation also led to radiosensitization in TNBC tumor xenografts with significantly increased tumor growth delay and overall survival. Mechanistically, BUB1 ablation inhibited the repair of radiation-induced DNA double strand breaks (DSBs). BUB1 ablation stabilized phospho-DNAPKcs (S2056) following RT such that half-lives could not be estimated. In contrast, RT alone caused BUB1 stabilization, but pre-treatment with BUB1 inhibitor prevented stabilization (t1/2, ~8 h). Nuclear and chromatin-enriched fractionations illustrated an increase in recruitment of phospho- and total-DNAPK, and KAP1 to chromatin indicating that BUB1 is indispensable in the activation and recruitment of non-homologous end joining (NHEJ) proteins to DSBs. Additionally, BUB1 staining of TNBC tissue microarrays demonstrated significant correlation of BUB1 protein expression with tumor grade.

CONCLUSIONS

BUB1 ablation sensitizes TNBC cell lines and xenografts to RT and BUB1 mediated radiosensitization may occur through NHEJ. Together, these results highlight BUB1 as a novel molecular target for radiosensitization in women with TNBC.

BUB1 Inhibition Sensitizes TNBC Cell Lines to Chemotherapy and Radiotherapy

BUB1 is overexpressed in most human solid cancers, including breast cancer. Higher BUB1 levels are associated with a poor prognosis, especially in patients with triple-negative breast cancer (TNBC). Women with TNBC often develop resistance to chemotherapy and radiotherapy, which are still the mainstay of treatment for TNBC. Our previous studies demonstrated that a BUB1 kinase inhibitor (BAY1816032) reduced tumor cell proliferation and significantly enhanced radiotherapy efficacy in TNBC. In this study, we evaluated the effectiveness of BAY1816032 with a PARP inhibitor (olaparib), platinum agent (cisplatin), and microtubule poison (paclitaxel) alone or in combination with radiotherapy using cytotoxicity and clonogenic survival assays. BUB1 inhibitors sensitized BRCA1/2 wild-type SUM159 and MDA-MB-231 cells to olaparib, cisplatin, and paclitaxel synergistically (combination index; CI < 1). BAY1816032 significantly increased the radiation sensitization of SUM159 and MDA-MB-231 by olaparib, cisplatin, or paclitaxel at non-toxic concentrations (doses well below the IC50 concentrations). Importantly, the small molecular inhibitor of BUB1 synergistically (CI < 1) sensitized the BRCA mutant TNBC cell line HCC1937 to olaparib. Furthermore, the BUB1 inhibitor significantly increased the radiation enhancement ratio (rER) in HCC1937 cells (rER 1.34) compared to either agent alone (BUB1i rER 1.19; PARPi rER 1.04). The data presented here are significant as they provide proof that inhibition of BUB1 kinase activity sensitizes TNBC cell lines to a PARP inhibitor and radiation, irrespective of BRCA1/2 mutation status. Due to the ability of the BUB1 inhibitor to sensitize TNBC to different classes of drugs (platinum, PARPi, microtubule depolarization inhibitors), this work strongly supports the role of BUB1 as a novel molecular target to improve chemoradiation efficacy in TNBC and provides a rationale for the clinical evaluation of BAY1816032 as a chemosensitizer and chemoradiosensitizer in TNBC.

BUB1 regulates non-homologous end joining pathway to mediate radioresistance in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer subtype often treated with radiotherapy (RT). Due to its intrinsic heterogeneity and lack of effective targets, it is crucial to identify novel molecular targets that would increase RT efficacy. Here we demonstrate the role of BUB1 (cell cycle Ser/Thr kinase) in TNBC radioresistance and offer a novel strategy to improve TNBC treatment.

Methods

Gene expression analysis was performed to look at genes upregulated in TNBC patient samples compared to other subtypes. Cell proliferation and clonogenic survivals assays determined the IC 50 of BUB1 inhibitor (BAY1816032) and radiation enhancement ratio (rER) with pharmacologic and genomic BUB1 inhibition. Mammary fat pad xenografts experiments were performed in CB17/SCID. The mechanism through which BUB1 inhibitor sensitizes TNBC cells to radiotherapy was delineated by γ-H2AX foci assays, BLRR, Immunoblotting, qPCR, CHX chase, and cell fractionation assays.

Results

BUB1 is overexpressed in BC and its expression is considerably elevated in TNBC with poor survival outcomes. Pharmacological or genomic ablation of BUB1 sensitized multiple TNBC cell lines to cell killing by radiation, although breast epithelial cells showed no radiosensitization with BUB1 inhibition. Kinase function of BUB1 is mainly accountable for this radiosensitization phenotype. BUB1 ablation also led to radiosensitization in TNBC tumor xenografts with significantly increased tumor growth delay and overall survival. Mechanistically, BUB1 ablation inhibited the repair of radiation-induced DNA double strand breaks (DSBs). BUB1 ablation stabilized phospho-DNAPKcs (S2056) following RT such that half-lives could not be estimated. In contrast, RT alone caused BUB1 stabilization, but pre-treatment with BUB1 inhibitor prevented stabilization (t 1/2 , ∼8 h). Nuclear and chromatin-enriched fractionations illustrated an increase in recruitment of phospho- and total-DNAPK, and KAP1 to chromatin indicating that BUB1 is indispensable in the activation and recruitment of non-homologous end joining (NHEJ) proteins to DSBs. Additionally, BUB1 staining of TNBC tissue microarrays demonstrated significant correlation of BUB1 protein expression with tumor grade.

Conclusions

BUB1 ablation sensitizes TNBC cell lines and xenografts to RT and BUB1 mediated radiosensitization may occur through NHEJ. Together, these results highlight BUB1 as a novel molecular target for radiosensitization in women with TNBC.

BUB1 inhibition sensitizes lung cancer cell lines to radiotherapy and chemoradiotherapy

Background

Lung cancer is a major public health concern, with high incidence and mortality. Despite advances in targeted therapy and immunotherapy, microtubule stabilizers (paclitaxel, docetaxel), DNA intercalating platinum drugs (cisplatin) and radiation therapy continue to play a critical role in the management of locally advanced and metastatic lung cancer. Novel molecular targets would provide opportunities for improving the efficacies of radiotherapy and chemotherapy.

Hypothesis

We hypothesize that BUB1 (Ser/Thr kinase) is over-expressed in lung cancers and that its inhibition will sensitize lung cancers to chemoradiation.

Methods

BUB1 inhibitor (BAY1816032) was combined with platinum (cisplatin), microtubule poison (paclitaxel), a PARP inhibitor (olaparib) and radiation in cell proliferation and radiation sensitization assays. Biochemical and molecular assays were used to evaluate their impact on DNA damage signaling and cell death mechanisms.

Results

BUB1 expression assessed by immunostaining of lung tumor microarrays (TMAs) confirmed higher BUB1 expression in NSCLC and SCLC compared to that of normal tissues. BUB1 overexpression in lung cancer tissues correlated directly with expression of TP53 mutations in non-small cell lung cancer (NSCLC). Elevated BUB1 levels correlated with poorer overall survival in NSCLC and small cell lung cancer (SCLC) patients. A BUB1 inhibitor (BAY1816032) synergistically sensitized lung cancer cell lines to paclitaxel and olaparib. Additionally, BAY1816032 enhanced cell killing by radiation in both NSCLC and SCLC. Molecular changes following BUB1 inhibition suggest a shift towards pro-apoptotic and anti-proliferative states, indicated by altered expression of BAX, BCL2, PCNA, and Caspases 9 and 3.

Conclusion

A direct correlation between BUB1 protein expression and overall survival was shown. BUB1 inhibition sensitized both NSCLC and SCLC to various chemotherapies (cisplatin, paclitaxel) and targeted therapy (PARPi). Furthermore, we present the novel finding that BUB1 inhibition sensitized both NSCLC and SCLC to radiotherapy and chemoradiation. Our results demonstrate BUB1 inhibition as a promising strategy to sensitize lung cancers to radiation and chemoradiation therapies.

Bub1 suppresses inflammatory arthritis-associated bone loss in mice through inhibition of TNFα-mediated osteoclastogenesis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterized by synovitis, bone and cartilage destruction, and increased fracture risk with bone loss. Although disease-modifying antirheumatic drugs have dramatically improved clinical outcomes, these therapies are not universally effective in all patients because of the heterogeneity of RA pathogenesis. Therefore, it is necessary to elucidate the molecular mechanisms underlying RA pathogenesis, including associated bone loss, in order to identify novel therapeutic targets. In this study, we found that Budding uninhibited by benzimidazoles 1 (BUB1) was highly expressed in RA patients' synovium and murine ankle tissue with arthritis. As CD45+CD11b+ myeloid cells are a Bub1 highly expressing population among synovial cells in mice, myeloid cell-specific Bub1 conditional knockout (Bub1ΔLysM) mice were generated. Bub1ΔLysM mice exhibited reduced femoral bone mineral density when compared with control (Ctrl) mice under K/BxN serum-transfer arthritis, with no significant differences in joint inflammation or bone erosion based on a semi-quantitative erosion score and histological analysis. Bone histomorphometry revealed that femoral bone mass of Bub1ΔLysM under arthritis was reduced by increased osteoclastic bone resorption. RNA-seq and subsequent Gene Set Enrichment Analysis demonstrated a significantly enriched nuclear factor-kappa B pathway among upregulated genes in receptor activator of nuclear factor kappa B ligand (RANKL)-stimulated bone marrow-derived macrophages (BMMs) obtained from Bub1ΔLysM mice. Indeed, osteoclastogenesis using BMMs derived from Bub1ΔLysM was enhanced by RANKL and tumor necrosis factor-α or RANKL and IL-1β treatment compared with Ctrl. Finally, osteoclastogenesis was increased by Bub1 inhibitor BAY1816032 treatment in BMMs derived from wildtype mice. These data suggest that Bub1 expressed in macrophages plays a protective role against inflammatory arthritis-associated bone loss through inhibition of inflammation-mediated osteoclastogenesis.

Electric field induced the changes in structure and function of human transforming growth factor beta receptor type I: from molecular dynamics to docking

The transforming growth factor beta (TGF-β) signaling pathway is believed to play essential roles in several physiological activities, including cancer. TGF-β receptor type I (TBR-I) is a key membrane receptor protein in the TGF-β signaling pathway, which relates to many intracellular biological effects. In recent years, cold atmospheric plasma (CAP) has been found to have promising prospects in selective anticancer therapy and has confirmed its essential role in the TGF-β signaling pathway. However, the ambiguous effect of CAP-induced electric field (EF) on TBR-I still limits the application of CAP in clinical therapy. Molecular dynamics is applied to assess the effect of EF on the structure of the extracellular domain of TBR-I using a series of indicators and methods, and then we discuss the ligand binding ability of TBR-I. Results show that moderate EF intensities' structural restraints may contribute to the structural stability and ligand-binding ability of TBR-I, but an EF higher than 0.1 V/nm will be harmful. What's more, EF induces a change in the docking interface of TBR-I, showing the conformation and position of special sequences of residues decide the ligand binding surface. The relevant results suggest that CAP-induced EF plays a crucial role in receptor-receptor interaction and provides significant guidelines for EF-related anticancer therapy.Communicated by Ramaswamy H. Sarma.

KIF4A promotes epithelial-mesenchymal transition by activating the TGF-β/SMAD signaling pathway in glioma cells

Gliomas are the most prevalent type of primary brain tumor, with poor prognosis reported in patients with high-grade glioma. Kinesin family member 4 A (KIF4A) stimulates the proliferation, migration, and invasion of tumor cells. However, its function in gliomas has not been clearly established. Therefore, this study aimed to investigate the effects of KIF4A on the epithelial-mesenchymal transition and invasion of glioma cells. We searched The Cancer Genome Atlas and Chinese Glioma Genome Atlas databases to identify KIF4A-related signaling pathways and downstream genes. We further validated them using western blotting, transwell migration and invasion, wound-healing scratch, and dual-luciferase reporter assays in U251 and U87 human glioblastoma cells. Our analysis of the Cancer Genome Atlas and Chinese Glioma Genome Atlas data showed elevated KIF4A expression in patients with gliomas and was associated with clinical grade. Here, KIF4A overexpression promoted the migration, invasion, and proliferation of glioma cells, whereas KIF4A knockdown showed contrasting results. Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) analyses demonstrated that KIF4A positively controls TGF-β/SMAD signaling in glioma cells. Additionally, genetic correlation analysis revealed that KIF4A transcriptionally controls benzimidazoles-1 expression in glioma cells. KIF4A promotes the epithelial-mesenchymal transition by regulating the TGF-β/SMAD signaling pathway via benzimidazoles-1 in glioma cells.

Expression of the checkpoint kinase BUB1 is a predictor of response to cancer therapies

The identification of clinically-relevant biomarkers is of upmost importance for the management of cancer, from diagnosis to treatment choices. We performed a pan-cancer analysis of the mitotic checkpoint budding uninhibited by benzimidazole 1 gene BUB1, in the attempt to ascertain its diagnostic and prognostic values, specifically in the context of drug response. BUB1 was found to be overexpressed in the majority of cancers, and particularly elevated in clinically aggressive molecular subtypes. Its expression was correlated with clinico-phenotypic features, notably tumour staging, size, invasion, hypoxia, and stemness. In terms of prognostic value, the expression of BUB1 bore differential clinical outcomes depending on the treatment administered in TCGA cancer cohorts, suggesting sensitivity or resistance, depending on the expression levels. We also integrated in vitro drug sensitivity data from public projects based on correlation between drug efficacy and BUB1 expression to produce a list of candidate compounds with differential responses according to BUB1 levels. Gene Ontology enrichment analyses revealed that BUB1 overexpression in cancer is associated with biological processes related to mitosis and chromosome segregation machinery, reflecting the mechanisms of action of drugs with a differential effect based on BUB1 expression.

Uncovering lupus nephritis-specific genes and the potential of TNFRSF17-targeted immunotherapy: a high-throughput sequencing study

Introduction

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE). This study aimed to identify LN specific-genes and potential therapeutic targets.

Methods

We performed high-throughput transcriptome sequencing on peripheral blood mononuclear cells (PBMCs) from LN patients. Healthy individuals and SLE patients without LN were used as controls. To validate the sequencing results, qRT-PCR was performed for 5 upregulated and 5 downregulated genes. Furthermore, the effect of the TNFRSF17-targeting drug IBI379 on patient plasma cells and B cells was evaluated by flow cytometry.

Results

Our analysis identified 1493 and 205 differential genes in the LN group compared to the control and SLE without LN groups respectively, with 70 genes common to both sets, marking them as LN-specific. These LN-specific genes were significantly enriched in the 'regulation of biological quality' GO term and the cell cycle pathway. Notably, several genes including TNFRSF17 were significantly overexpressed in the kidneys of both LN patients and NZB/W mice. TNFRSF17 levels correlated positively with urinary protein levels, and negatively with complement C3 and C4 levels in LN patients. The TNFRSF17-targeting drug IBI379 effectively induced apoptosis in patient plasma cells without significantly affecting B cells.

Discussion

Our findings suggest that TNFRSF17 could serve as a potential therapeutic target for LN. Moreover, IBI379 is presented as a promising treatment option for LN.

Mutual regulation of TGFβ-induced oncogenic EMT, cell cycle progression and the DDR

TGFβ signaling and the DNA damage response (DDR) are two cellular toolboxes with a strong impact on cancer biology. While TGFβ as a pleiotropic cytokine affects essentially all hallmarks of cancer, the multifunctional DDR mostly orchestrates cell cycle progression, DNA repair, chromatin remodeling and cell death. One oncogenic effect of TGFβ is the partial activation of epithelial-to-mesenchymal transition (EMT), conferring invasiveness, cellular plasticity and resistance to various noxae. Several reports show that both individual networks as well as their interface affect chemo-/radiotherapies. However, the underlying mechanisms remain poorly resolved. EMT often correlates with TGFβ-induced slowing of proliferation, yet numerous studies demonstrate that particularly the co-activated EMT transcription factors counteract anti-proliferative signaling in a partially non-redundant manner. Collectively, evidence piled up over decades underscore a multifaceted, reciprocal inter-connection of TGFβ signaling / EMT with the DDR / cell cycle progression, which we will discuss here. Altogether, we conclude that full cell cycle arrest is barely compatible with the propagation of oncogenic EMT traits and further propose that 'EMT-linked DDR plasticity' is a crucial, yet intricate facet of malignancy, decisively affecting metastasis formation and therapy resistance.

Inhibition of the serine/threonine kinase BUB1 reverses taxane resistance in prostate cancer

Men with incurable castration resistant prostate cancer (CRPC) are typically treated with taxanes; however, drug resistance rapidly develops. We previously identified a clinically relevant seven gene network in aggressive CRPC, which includes the spindle assembly checkpoint (SAC) kinase BUB1. Since SAC is deregulated in taxane resistant PC, we evaluated BUB1 and found that it was over-expressed in advanced PC patient datasets and taxane resistant PC cells. Treatment with a specific BUB1 kinase inhibitor re-sensitized resistant CRPC cells, including cells expressing constitutively active androgen receptor (AR) variants, to clinically used taxanes. Consistent with a role of AR variants in taxane resistance, ectopically expressed AR-V7 increased BUB1 levels and reduced sensitivity to taxanes. This work shows that disruption of BUB1 kinase activity reverted resistance to taxanes, which is essential to advancing BUB1 as a potential therapeutic target for intractable chemotherapy resistant CRPC including AR variant driven CRPC, which lacks durable treatment options.

Budding uninhibited by benzimidazoles-1 (BUB1) regulates EGFR signaling by reducing EGFR internalization

EGFR signaling initiates upon ligand binding which leads to activation and internalization of the receptor-ligand complex. Here, we evaluated if BUB1 impacted EGFR signaling by regulating EGFR receptor internalization and activation. BUB1 was ablated genomically (siRNA) or biochemically (2OH-BNPP1) in cells. EGF ligand was used to initiate EGFR signaling while disuccinimidyl suberate (DSS) was used for cross linking cellular proteins. EGFR signaling was measured by western immunoblotting and receptor internalization was evaluated by fluorescent microscopy (pEGFR (pY1068) colocalization with early endosome marker EEA1). siRNA mediated BUB1 depletion led to an overall increase in total EGFR levels and more phospho-EGFR (Y845, Y1092, and Y1173) dimers while the amount of total EGFR (non-phospho) dimers remained unchanged. BUB1 inhibitor (BUB1i) decreased EGF mediated EGFR signaling including pEGFR Y845, pAKT S473 and pERK1/2 in a time dependent manner. Additionally, BUB1i also reduced EGF mediated pEGFR (Y845) dimers (asymmetric dimers) without affecting total EGFR dimers (symmetric dimers) indicating that dimerization of inactive EGFR is not affected by BUB1. Furthermore, BUB1i blocked EGF mediated EGFR degradation (increase in EGFR half-life) without impacting half-lives of HER2 or c-MET. BUB1i also reduced co-localization of pEGFR with EEA1 positive endosomes suggesting that BUB1 might modulate EGFR endocytosis. Our data provide evidence that BUB1 protein and its kinase activity may regulate EGFR activation, endocytosis, degradation, and downstream signaling without affecting other members of the receptor tyrosine kinase family.

Identification of immune-related gene signature for predicting prognosis in uterine corpus endometrial carcinoma

The objective of this study is to develop a gene signature related to the immune system that can be used to create personalized immunotherapy for Uterine Corpus Endometrial Carcinoma (UCEC). To classify the UCEC samples into different immune clusters, we utilized consensus clustering analysis. Additionally, immune correlation algorithms were employed to investigate the tumor immune microenvironment (TIME) in diverse clusters. To explore the biological function, we conducted GSEA analysis. Next, we developed a Nomogram by integrating a prognostic model with clinical features. Finally, we performed experimental validation in vitro to verify our prognostic risk model. In our study, we classified UCEC patients into three clusters using consensus clustering. We hypothesized that cluster C1 represents the immune inflammation type, cluster C2 represents the immune rejection type, and cluster C3 represents the immune desert type. The hub genes identified in the training cohort were primarily enriched in the MAPK signaling pathway, as well as the PD-L1 expression and PD-1 checkpoint pathway in cancer, all of which are immune-related pathways. Cluster C1 may be a more suitable for immunotherapy. The prognostic risk model showed a strong predictive ability. Our constructed risk model demonstrated a high level of accuracy in predicting the prognosis of UCEC, while also effectively reflecting the state of TIME.

Bub1 and Bub3 regulate metabolic adaptation via macrolipophagy in Drosophila

Lipophagy, the process of selective catabolism of lipid droplets (LDs) by autophagy, maintains lipid homeostasis and provides cellular energy under metabolic adaptation, yet its underlying mechanism remains largely ambiguous. Here, we show that the Bub1-Bub3 complex, the crucial regulator involved in the whole process of chromosome alignment and separation during mitosis, controls the fasting-induced lipid catabolism in the fat body (FB) of Drosophila. Bidirectional deviations of the Bub1 or Bub3 level affect the consumption of triacylglycerol (TAG) of fat bodies and the survival rate of adult flies under starving. Moreover, Bub1 and Bub3 work together to attenuate lipid degradation via macrolipophagy upon fasting. Thus, we uncover physiological roles of the Bub1-Bub3 complex on metabolic adaptation and lipid metabolism beyond their canonical mitotic functions, providing insights into the in vivo functions and molecular mechanisms of macrolipophagy during nutrient deprivation.

Downregulated miR-495-3p in colorectal cancer targets TGFβR1, TGFβR2, SMAD4 and BUB1 genes and induces cell cycle arrest

BACKGROUND

Hsa-miR-495 (miR-495) has been extensively investigated in cancer initiation and progression. On the other hand, our bioinformatics analysis suggested that miR-495 exerts its effects through targeting of TGFβ signaling components.

METHODS & RESULTS

In order to investigate such an effect, miR-495 precursor was overexpressed in HEK293T, SW480, and HCT116 cells, which was followed by downregulation of TGFβR1, TGFβR2, SMAD4, and BUB1 putative target genes, detected by RT-qPCR. Also, luciferase assay supported the direct interaction of miR-495 with 3'UTR sequences of TGFβR1, TGFβR2, SMAD4, and BUB1 genes. Furthermore, a negative correlation of expression between miR-495-3p and some of these target genes was deduced in a set of colorectal and breast cancer cell lines. Then, flow cytometry analysis showed that the overexpression of miR-495 in HCT116 and HEK293T resulted in an arrest at the G1 phase. Consistently, western blotting analysis showed a significant reduction of the Cyclin D1 protein in the cells overexpressing miR-495, pointing to downregulation of the TGFβ signaling pathway and cell cycle arrest. Finally, microarray data analysis showed that miR-495-3p is significantly downregulated in colorectal tumors, compared to the normal pairs.

CONCLUSIONS

Overall, the results of the current study introduced miR-495-3p as a cell cycle progression suppressor, which may negatively regulate TGFβR1, TGFβR2, SMAD4, and BUB1 genes. This finding suggests miR-495-3p as a tumor suppressor candidate for further evaluation.

Budding uninhibited by benzimidazoles 1 overexpression is associated with poor prognosis and malignant phenotype: A promising therapeutic target for lung adenocarcinoma

BACKGROUND

The budding uninhibited by benzimidazoles (BUB) family is involved in the cell cycle process as mitotic checkpoint components. Abnormal proliferation is a vital process in the development of lung adenocarcinoma (LUAD). Nevertheless, the roles of BUB1 in LUAD remain unclear. In this study, we evaluated the prognostic value and biological functions of BUB1 in LUAD using data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), clinical LUAD samples, and in vitro experiments.

METHODS

The expression, prognostic significance, functions, immune infiltration, and methylation of BUB1 in LUAD were comprehensively analyzed using TCGA, GEO, Gene Expression Profiling Interactive Analysis, Metascape, cBioPortal, MethSurv, and cancerSEA databases. Furthermore, we performed a battery of in vitro experiments and immunohistochemistry (IHC) to verify the bioinformatics results.

RESULTS

Multivariate analysis revealed that BUB1 overexpression was an independent prognostic factor (hazard ratio = 1.499, p = 0.013). Functional enrichment analysis showed that BUB1 was correlated with cell cycle, proliferation, DNA repair, DNA damage, and invasion (p < 0.05). Finally, in vitro experiments showed that downregulation of BUB1 inhibited the proliferation, migration, and invasion of LUAD cells and promoted LUAD cell apoptosis. IHC also showed that BUB1 was overexpressed in LUAD (p < 0.001) and was significantly associated with poor prognosis (p < 0.001).

CONCLUSIONS

Our bioinformatics and IHC analyses revealed that BUB1 overexpression was an adverse prognostic factor in LUAD. In vitro experiments demonstrated that BUB1 promoted tumor cell proliferation, migration, and invasion in LUAD. These results indicated that BUB1 was a promising biomarker and potential therapeutic target in LUAD.

Hypoxia promotes epithelial-mesenchymal transition in lung cancer cells via regulating the NRF2/miR‑27a/BUB1 pathway

PURPOSE

Lung cancer (LC) is the most common malignancy in the world. It is well that hypoxia is common in lung cancer, which contributes to lung cancer progression and metastasis [1]. miRNA-27a as a repressor factor is a lowly expression within non-small cell lung cancer (NSCLC). However, the molecular mechanism between miR-27a and hypoxia in lung cancer progression remains poorly understood. This study aims to explore hypoxia promotes epithelial-mesenchymal transition in lung cancer cells via regulating the NRF2/miR‑27a/BUB1 pathway.

METHODS

We detect the expression of miR-27a after exposure to hypoxia conditions in lung cancer cells via qPCR. Using MTT assay and colony assay to assess the ability of proliferation in lung cancer cells under hypoxia or transfect miR-27a mimics. The capability of migration and invasion was evaluated by wound healing assay and Boyden-chamber assay. The mRNA and protein expression of EMT markers was respectively detected by qPCR and western blot. We detected NRF2 occupancy at the miR-27a promoter by ChIP-Seq analysis. Meanwhile, the luciferase assay verified BUB1 as a direct target of miR-27a.

RESULTS

We found hypoxia promotes lung cancer cell proliferation, migration, invasion, and the epithelial-mesenchymal transition (EMT) process by inhibiting the miR-27a expression. miR-27a mimics significantly reduced the promotion effect of hypoxia on the invasion and proliferation of lung cancer cells. NRF2 as regulating the oxidation/anti-oxidation factor was activated under hypoxia conditions. The activation of NRF2 repressed miR-27a expression. On the contrary, the inhibitory effect of hypoxia on miR-27a was reversed when the NFE2L2 gene was silenced. Ectopic expression of NRF2 inhibited miR-27a expression under normoxia. We further validated BUB1 as a direct target of the miR-27a by luciferase assay.

CONCLUSION

Hypoxia promotes invasion and epithelial-mesenchymal transition of Lung cancer cells by regulating the NRF2/miR-27a/BUB1 axis.

Comprehensive analysis of roles of atrial-fibrillation-related genes in lung adenocarcinoma using bioinformatic methods

Atrial fibrillation (AF) is the most common tachyarrhythmia in the world. Lung cancer is the leading cause of cancer deaths in 93 countries. Previous studies demonstrated that the prevalence of AF was higher in patients with lung cancer. However, research on the associations between AF and lung cancer is still rare. In the present study, we first identified AF-related genes using weighted gene correlation network analysis. We then analyzed the expression profiles, prognosis, immune infiltration, and methylation characteristics of these genes in LUAD patients using bioinformatics analysis. We found several AF-related genes, including CBX3, BUB1, DSC2, P4HA1, and CYP4Z1, which differently expressed between tumor and normal tissues. Survival analysis demonstrated that CYP4Z1 was positively correlated with overall survival in LUAD patients, while CBX3, BUB1, DSC2, and P4HA1 were negatively correlated. Moreover, we found that the methylation level of DSC2 in normal lung tissues was significantly higher than that in tumor tissues, and six methylation sites in the DNA sequences of DSC2 were identified negatively correlated with its expression levels. Immune infiltration analysis suggested that levels of immune cell infiltration were related to gene expression levels in varying degrees. We identified AF-related genes and found these genes were correlated with prognosis, immune infiltration, and methylation levels in lung cancer patients. We also constructed a risk signature based on these genes in LUAD patients. We hoped that the current study could provide a novel insight into roles of AF-related genes in lung cancer patients.

A Morphomolecular Approach to Alveolar Capillary Dysplasia

Alveolar capillary dysplasia (ACD) is a rare lung developmental disorder leading to persistent pulmonary arterial hypertension and fatal outcomes in newborns. The current study analyzed the microvascular morphology and the underlying molecular background of ACD. One ACD group (n = 7), one pulmonary arterial hypertension group (n = 20), and one healthy con1trol group (n = 16) were generated. Samples of histologically confirmed ACD were examined by exome sequencing and array-based comparative genomic hybridization. Vascular morphology was analyzed using scanning electron microscopy of microvascular corrosion casts. Gene expression and biological pathways were analyzed using two panels on inflammation/kinase-specific genes and a comparison analysis tool. Compartment-specific protein expression was analyzed using immunostaining. In ACD, there was an altered capillary network, a high prevalence of intussusceptive angiogenesis, and increased activity of C-X-C motif chemokine receptor 4 (CXCR4), hypoxia-inducible factor 1α (HIF1A), and angiopoietin signaling pathways compared with pulmonary arterial hypertension/healthy controls. Histologically, there was a markedly increased prevalence of endothelial tyrosine kinase receptor (TEK/TIE2)⁺ macrophages in ACD, compared with the other groups, whereas the CXCR4 ligand CXCL12 and HIF1A showed high expression in all groups. ACD is characterized by dysfunctional capillaries and a high prevalence of intussusceptive angiogenesis. The results indicate that endothelial CXCR4, HIF1A, and angiopoietin signaling as well as TIE2⁺ macrophages are crucial for the induction of intussusceptive angiogenesis and vascular remodeling. Future studies should address the use of anti-angiogenic agents in ACD, where TIE2 appears as a promising target.

Identification and Validation of a Potential Stemness-Associated Biomarker in Hepatocellular Carcinoma

Background

Cancer stem cells (CSCs) are typically related to metastasis, recurrence, and drug resistance in malignant tumors. However, the biomarker and mechanism of CSCs need further exploration. This study is aimed at comprehensively depicting the stemness characteristics and identify a potential stemness-associated biomarker in hepatocellular carcinoma (HCC).

Methods

The data of HCC patients from The Cancer Genome Atlas (TCGA) were collected and divided based on the mRNA expression-based stemness index (mRNAsi) in this study. Weighted gene coexpression network analysis (WGCNA) and the protein-protein interaction (PPI) network were performed, and the genes were screened through the Cytoscape software. Then, we constructed a prognostic expression signature using the multivariable Cox analysis and verified using the GEO and ICGC databases. Even more importantly, we used the three-dimensional (3D) fibrin gel to enrich the tumor-repopulating cells (TRCs) to validate the expression of the signature in CSCs by quantitative RT-PCR.

Results

mRNAsi was significantly elevated in tumor and high-mRNAsi score was associated with poor overall survival in HCC. The positive stemness-associated (blue) module with 737 genes were screened based on WGCNA, and Budding uninhibited by benzimidazoles 1 (BUB1) was identified as the hub gene highly related to stemness in HCC. Then, the prognostic value and stemness characteristics were well validated in the ICGC and GSE14520 cohorts. Further analysis showed the expression of BUB1 was elevated in TRCs.

Conclusion

BUB1, as a potential stemness-associated biomarker, could serve as a therapeutic CSCs-target and predicted the clinical outcomes of patients with HCC.

BUB1 predicts poor prognosis and immune status in liver hepatocellular carcinoma

Accurate assessment of the tumour immune microenvironment promotes individualized immunotherapy regimens and screens dominant populations suitable for immunotherapy. Therefore, potential molecular markers were investigated to make an overall assessment of the immune microenvironment status of liver hepatocellular carcinoma (LIHC). In this study, a total of 121 differentially expressed genes (DEGs) were identified, and DEGs were enriched in the epithelial-mesenchymal transition, hypoxia, myogenesis, and p53 pathways. A total of 20 hub genes were selected and a strong correlation was identified between these hub genes and prognosis. The expression of budding uninhibited by benzimidazoles 1 (BUB1) was found to be upregulated in LIHC and was strongly related to immune cells and immune checkpoint molecule expression. Immunohistochemistry (IHC) indicated that BUB1 expression was higher in LIHC tissues than in normal liver tissues. BUB1 knockdown resulted in reduced proliferation and vertical migration ability of LIHC cells, and reduced the expression of phospho-SMAD family member 2 and phospho-SMAD family member 3 proteins. IHC showed that BUB1 expression was accompanied by immune cell infiltration into LIHC tissues. These results suggest that BUB1 may serve as a potential prognostic biomarker for LIHC and as an indicator of its immune status.

Biallelic BUB1 mutations cause microcephaly, developmental delay, and variable effects on cohesion and chromosome segregation

Budding uninhibited by benzimidazoles (BUB1) contributes to multiple mitotic processes. Here, we describe the first two patients with biallelic BUB1 germline mutations, who both display microcephaly, intellectual disability, and several patient-specific features. The identified mutations cause variable degrees of reduced total protein level and kinase activity, leading to distinct mitotic defects. Both patients’ cells show prolonged mitosis duration, chromosome segregation errors, and an overall functional spindle assembly checkpoint. However, while BUB1 levels mostly affect BUBR1 kinetochore recruitment, impaired kinase activity prohibits centromeric recruitment of Aurora B, SGO1, and TOP2A, correlating with anaphase bridges, aneuploidy, and defective sister chromatid cohesion. We do not observe accelerated cohesion fatigue. We hypothesize that unresolved DNA catenanes increase cohesion strength, with concomitant increase in anaphase bridges. In conclusion, BUB1 mutations cause a neurodevelopmental disorder, with clinical and cellular phenotypes that partially resemble previously described syndromes, including autosomal recessive primary microcephaly, mosaic variegated aneuploidy, and cohesinopathies.

Nuclear PD-L1 promotes cell cycle progression of BRAF-mutated colorectal cancer by inhibiting THRAP3

Colorectal cancers (CRCs) with the BRAF V600E mutation exhibit upregulation of programmed death ligand 1 (PD-L1) but fail to respond to immunotherapy targeting programmed cell death protein 1 (PD-1)/PD-L1. Recent studies have explored the intracellular functions of PD-L1. Here, we demonstrate that PD-L1 was highly expressed in both the cytoplasm and nucleus of BRAF-mutated CRC tumor cells and tissues. Nuclear PD-L1 (nPD-L1) promoted the growth of tumor cells both in vitro and in vivo. Mechanistic investigations revealed that PD-L1 translocation into the nucleus was facilitated by the binding of p-ERK. Further, nPD-L1 upregulated the expression of cell cycle regulator BUB1 via interactions with thyroid hormone receptor-associated protein 3 (THRAP3), thereby accelerating cell cycle progression and promoting cell proliferation. Moreover, BRAF V600E-mutated CRC cells exhibited upregulation of PD-L1 expression via the transcription factor LEF-1. These findings reveal a novel role of nPD-L1, which promotes cell cycle progression in an immune-independent manner in BRAF V600E-mutated CRC. Our study provides novel insight into the mechanisms underlying BRAF V600E-mutated CRC progression.

Inhibitors of the Bub1 spindle assembly checkpoint kinase: synthesis of BAY-320 and comparison with 2OH-BNPP1

Bub1 is a serine/threonine kinase proposed to function centrally in mitotic chromosome alignment and the spindle assembly checkpoint (SAC); however, its role remains controversial. Although it is well documented that Bub1 phosphorylation of Histone 2A at T120 (H2ApT120) recruits Sgo1/2 to kinetochores, the requirement of its kinase activity for chromosome alignment and the SAC is debated. As small-molecule inhibitors are invaluable tools for investigating kinase function, we evaluated two potential Bub1 inhibitors: 2OH-BNPPI and BAY-320. After confirming that both inhibit Bub1 in vitro, we developed a cell-based assay for Bub1 inhibition. We overexpressed a fusion of Histone 2B and Bub1 kinase region, tethering it in proximity to H2A to generate a strong ectopic H2ApT120 signal along chromosome arms. Ectopic signal was effectively inhibited by BAY-320, but not 2OH-BNPP1 at concentrations tested. In addition, only BAY-320 was able to inhibit endogenous Bub1-mediated Sgo1 localization. Preliminary experiments using BAY-320 suggest a minor role for Bub1 kinase activity in chromosome alignment and the SAC; however, BAY-320 may exhibit off-target effects at the concentration required. Thus, 2OH-BNPP1 may not be an effective Bub1 inhibitor in cellulo, and while BAY-320 can inhibit Bub1 in cells, off-target effects highlight the need for improved Bub1 inhibitors.

Key signaling networks are dysregulated in patients with the adipose tissue disorder, lipedema

Objectives

Lipedema, a poorly understood chronic disease of adipose hyper-deposition, is often mistaken for obesity and causes significant impairment to mobility and quality-of-life. To identify molecular mechanisms underpinning lipedema, we employed comprehensive omics-based comparative analyses of whole tissue, adipocyte precursors (adipose-derived stem cells (ADSCs)), and adipocytes from patients with or without lipedema.

Methods

We compared whole-tissues, ADSCs, and adipocytes from body mass index–matched lipedema (n = 14) and unaffected (n = 10) patients using comprehensive global lipidomic and metabolomic analyses, transcriptional profiling, and functional assays.

Results

Transcriptional profiling revealed >4400 significant differences in lipedema tissue, with altered levels of mRNAs involved in critical signaling and cell function-regulating pathways (e.g., lipid metabolism and cell-cycle/proliferation). Functional assays showed accelerated ADSC proliferation and differentiation in lipedema. Profiling lipedema adipocytes revealed >900 changes in lipid composition and >600 differentially altered metabolites. Transcriptional profiling of lipedema ADSCs and non-lipedema ADSCs revealed significant differential expression of >3400 genes including some involved in extracellular matrix and cell-cycle/proliferation signaling pathways. One upregulated gene in lipedema ADSCs, Bub1, encodes a cell-cycle regulator, central to the kinetochore complex, which regulates several histone proteins involved in cell proliferation. Downstream signaling analysis of lipedema ADSCs demonstrated enhanced activation of histone H2A, a key cell proliferation driver and Bub1 target. Critically, hyperproliferation exhibited by lipedema ADSCs was inhibited by the small molecule Bub1 inhibitor 2OH-BNPP1 and by CRISPR/Cas9-mediated Bub1 gene depletion.

Conclusion

We found significant differences in gene expression, and lipid and metabolite profiles, in tissue, ADSCs, and adipocytes from lipedema patients compared to non-affected controls. Functional assays demonstrated that dysregulated Bub1 signaling drives increased proliferation of lipedema ADSCs, suggesting a potential mechanism for enhanced adipogenesis in lipedema. Importantly, our characterization of signaling networks driving lipedema identifies potential molecular targets, including Bub1, for novel lipedema therapeutics.

Molecular docking of two cytotoxic compounds from Calotropis gigantea leaves against therapeutic molecular target of pancreatic cancer

The utilization of natural compounds as therapeutic agents to treat pancreatic cancer has recently focused on natural drug research. Calotropis gigantea has long been believed to be a medicinal plant that helps in treating various diseases. The bioactive compounds 9-metoxipinoresinol and isoliquiritigenin isolated from C. gigantea leaves are proven to act as therapeutic agents by inhibiting the cancer cell growth of Panc-1 cells. This study aimed to screen the potential molecular inhibition mechanisms of 9-metoxipinoresinol and isoliquiritigenin against pancreatic cancer development in-silico. We analyzed the activity of the aforementioned two compounds as inhibitors of several proteins that play a role in the growth of pancreatic cancer cells, such as GCNT3, GOT1, c-Met, PPARγ, BUB1, and NF-κβ, through molecular docking investigation. Our data suggested that 9-metoxipinoresinol and isoliquiritigenin were able to have well interaction with the target proteins, in which the predicted affinity energy ranged between -6.8 and 8.7 kcal/mol. The docking scores of 9-metoxipinoresinol and isoliquiritigenin were higher than the standard drug used (gemcitabine). Based on the binding affinity energy, GCNT3 and BUB1 are potentially to be used as target molecules for cancer therapy using 9-metoxipinoresinol and isoliquiritigenin, respectively.

Inhibition of BUB1 suppresses tumorigenesis of osteosarcoma via blocking of PI3K/Akt and ERK pathways

Osteosarcoma (OS) is a primary malignant bone tumour that mainly affects teenagers, with patients displaying poor prognosis. Budding uninhibited by benzimidazoles 1 (BUB1), a type of serine/threonine kinase that is linked to pro-tumorigenic phenomena, has not been well studied in OS. Hence, this study aimed to explore the role of BUB1 in OS. The expression of BUB1 in OS specimens and cell lines was assessed using immunohistochemistry and Western blot analysis. Univariate and multivariate analyses were applied to evaluate the impact of BUB1 on patient survival. Cell counting kit-8, wound-healing and Transwell assays, as well as flow cytometry, were used to investigate the influence of BUB1 inhibition on OS in vitro. Moreover, a tumour xenograft model was established to investigate the in vivo effect of BUB1 inhibition on OS tumour growth. Results showed that BUB1 was overexpressed in OS specimens and cell lines. Furthermore, BUB1 overexpression was closely associated with the poor clinical outcomes of patients with OS. Inhibition of BUB1 markedly suppressed cell proliferation and tumour growth, cell migration, invasion and induced cell apoptosis of OS by blocking the PI3K/Akt and ERK signalling pathways. Thus, our study suggested that overexpression of BUB1 protein contributed to poor survival of OS patients and that inhibition of BUB1 resulted in considerable anti-tumour activity associated with proliferation, migration, invasion and apoptosis of OS.

Bioinformatics study on genes related to a high-risk postoperative recurrence of lung adenocarcinoma

In this study, we aimed to screen out genes associated with a high risk of postoperative recurrence of lung adenocarcinoma and investigate the possible mechanisms of the involvement of these genes in the recurrence of lung adenocarcinoma. We identify Hub genes and verify the expression levels and prognostic roles of these genes. Datasets of GSE40791, GSE31210, and GSE30219 were obtained from the Gene Expression Omnibus database. Enrichment analysis of gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed for the screened candidate genes using the DAVID database. Then, we performed protein-protein interaction (PPI) network analysis through the database STRING. Hub genes were screened out using Cytoscape software, and their expression levels were determined by the GEPIA database. Finally, we assessed the relationships of Hub genes expression levels and the time of survival. Forty-five candidate genes related to a high-risk of lung adenocarcinoma recurrence were screened out. Gene ontology analysis showed that these genes were enriched in the mitotic spindle assembly checkpoint, mitotic sister chromosome segregation, G2/M-phase transition of the mitotic cell cycle, and ATP binding, etc. KEGG analysis showed that these genes were involved predominantly in the cell cycle, p53 signaling pathway, and oocyte meiosis. We screened out the top ten Hub genes related to high expression of lung adenocarcinoma from the PPI network. The high expression levels of eight genes (TOP2A, HMMR, MELK, MAD2L1, BUB1B, BUB1, RRM2, and CCNA2) were related to short recurrence-free survival and they can be used as biomarkers for high risk of lung adenocarcinoma recurrence. This study screened out eight genes associated with a high risk of lung adenocarcinoma recurrence, which might provide novel insights into researching the recurrence mechanisms of lung adenocarcinoma as well as into the selection of targets in the treatment of the disease.

Mitotic kinases as drivers of the epithelial-to-mesenchymal transition and as therapeutic targets against breast cancers

Biological therapies against breast cancer patients with tumors positive for the estrogen and progesterone hormone receptors and Her2 amplification have greatly improved their survival. However, to date, there are no effective biological therapies against breast cancers that lack these three receptors or triple-negative breast cancers (TNBC). TNBC correlates with poor survival, in part because they relapse following chemo- and radio-therapies. TNBC is intrinsically aggressive since they have high mitotic indexes and tend to metastasize to the central nervous system. TNBCs are more likely to display centrosome amplification, an abnormal phenotype that results in defective mitotic spindles and abnormal cytokinesis, which culminate in aneuploidy and chromosome instability (known causes of tumor initiation and chemo-resistance). Besides their known role in cell cycle control, mitotic kinases have been also studied in different types of cancer including breast, especially in the context of epithelial-to-mesenchymal transition (EMT). EMT is a cellular process characterized by the loss of cell polarity, reorganization of the cytoskeleton, and signaling reprogramming (upregulation of mesenchymal genes and downregulation of epithelial genes). Previously, we and others have shown the effects of mitotic kinases like Nek2 and Mps1 (TTK) on EMT. In this review, we focus on Aurora A, Aurora B, Bub1, and highly expressed in cancer (Hec1) as novel targets for therapeutic interventions in breast cancer and their effects on EMT. We highlight the established relationships and interactions of these and other mitotic kinases, clinical trial studies involving mitotic kinases, and the importance that represents to develop drugs against these proteins as potential targets in the primary care therapy for TNBC.

Bub1 kinase in the regulation of mitosis

Accurate chromosome segregation is required for cell survival and organismal development. During mitosis, the spindle assembly checkpoint acts as a safeguard to maintain the high fidelity of mitotic chromosome segregation by monitoring the attachment of kinetochores to the mitotic spindle. Bub1 is a conserved kinase critical for the spindle assembly checkpoint. Bub1 also facilitates chromosome alignment and contributes to the regulation of mitotic duration. Here, focusing on the spindle assembly checkpoint and on chromosome alignment, we summarize the primary literature on Bub1, discussing its structure and functional domains, as well its regulation and roles in mitosis. In addition, we discuss recent evidence for roles of Bub1 beyond mitosis regulation in TGFβ signaling and telomere replication. Finally, we discuss the involvement of Bub1 in human diseases, especially in cancer, and the potential of using Bub1 as a drug target for therapeutic applications.

Screening of hub genes associated with prognosis in non-small cell lung cancer by integrated bioinformatics analysis

Background

Lung cancer is an intractable disease and the second leading cause of cancer-related deaths and morbidity in the world. This study conducted a bioinformatics analysis to identify critical genes associated with poor prognosis in non-small cell lung cancer (NSCLC).

Methods

We downloaded three datasets (GSE33532, GSE27262, and GSE18842) from the gene expression omnibus (GEO), and used the GEO2R online tools to identify the differentially expressed genes (DEGs). We then used the Search Tool for Retrieval of Interacting Genes (STRING) database to establish a protein-protein interaction (PPI) network and used the Cytoscape software to perform a module analysis of the PPI network. A Kaplan-Meier plotter was used to perform the overall survival (OS) analysis, and the Gene Expression Profiling Interactive Analysis (GEPIA) database was used for expression level analysis of hub genes. Further, the UALCAN database was used to validate the relationship between the gene expression level of each hub gene and clinical characteristics.

Results

We identified 254 DEGs, which were composed of 66 up-regulated genes and 188 down-regulated genes. Out of these, five DEGs were identified as hub genes (CDC20, BUB1, CCNB2, CCNB1, UBE2C) by constructing a PPI network. The use of a Kaplan-Meier plotter to generate patient survival curves suggested a strong relationship between the five hub genes with worse OS. Validation of the above results using the GEPIA database showed that all the hub genes were highly expressed in NSCLC tissues. Using the UALACN data mining platform, we found that the five hub genes are correlated with tumor stage and the status of node metastasis in NSCLC patients.

Conclusions

We identified five hub DEGs that might provide perspectives in the explorations of pathogenesis and treatments for NSCLC.

Identification of drug targets and potential molecular mechanisms for Wantong Jingu Tablet extract in treatment of rheumatoid arthritis: bioinformatics analysis of fibroblast-like synoviocytes

Background

Rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLSs) play important roles in pathogenesis of rheumatoid arthritis (RA). Wantong Jingu Tablet (WJT), a mixture of traditional Chinese medicine, is a potentially effective therapy for RA, but its underlying mechanism is unclear. In this study, we explore the effects of WJT on human RA-FLSs and the underlying molecular mechanism.

Methods

The major components of WJT were determined using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS). Cell proliferative ability was evaluated by CCK-8, colony formation assay, and EdU incorporation assay. Cell apoptotic capacity was examined by caspase-3 and caspase-9 activity test. Protein levels of Bax and Bcl-2 were investigated by western blotting. High-throughput sequencing and bioinformatics analysis were conducted to screen and identify targeted genes, followed by identification by qRT-PCR and western blotting.

Results

In this study, we have identified 346 compounds in WJT. Our results showed that WJT inhibited the RA-FLSs proliferation, and promoted apoptosis in a dose- and time-dependent manner. More importantly, 184 differentially expressed genes (DEGs) has been screened after WJT treatment based on DEGSeq2 and 278 DEGs was identified by DEGSeq2 combined with WGCNA. Then, 10 hub genes were identified based on two different analyses, while the expression levels of only SMC3, THOC1, BUB1, and STAG2 were decreased after WJT treatment, which was identical to the sequencing profiles.

Conclusions

WJT exerted its anti-proliferation and pro-apoptosis effects possibly through suppressing the expression of SMC3, THOC1, BUB1, and STAG2 in RA-FLSs. Thus, therapeutics targeting these genes may be a promising strategy for rescuing RA.

Budding Uninhibited by Benzimidazole-1 Insufficiency Prevents Acute Renal Failure in Severe Sepsis by Maintaining Anticoagulant Functions of Vascular Endothelial Cells

Severe sepsis is critical to health and can result in acute renal failure (ARF). Tissue factor (TF) and thrombomodulin (TM) play key roles in vascular endothelial functions by helping maintain microcirculation in the kidney. Budding uninhibited by benzimidazole-1 (Bub1) plays a role in Akt and JNK signaling, which control TF and TM, respectively. We hypothesized that Bub1 could control vascular endothelial function in sepsis. The aim of this study was to determine the role of Bub1 in septic ARF. We used Mouse cecum ligation and puncture (CLP) using low Bub1 expressing (Bub1) and wild-type (Bub1) mice in vivo and lipopolysaccharide (LPS) stimulation of human aortic endothelial cell (HAEC) in vitro. Bub1 mice had a higher survival rate after CLP than Bub1. Bub1 mice had more severe ARF after CLP than Bub1 with blood biochemical and pathological analyses. TF expression in Bub1 mice and control HAEC (control) significantly increased in the septic model compared with Bub1 and Bub1 silenced HAEC (siBub1). TM expression in the control significantly decreased after LPS stimulation compared with siBub1. Akt and JNK phosphorylation of siBub1 were attenuated after LPS stimulation. Associations of Bub1 with Akt or JNK after LPS stimulation of HAEC were detected using immunoprecipitation, suggesting that Bub1 is involved in the phosphorylation of Akt and JNK after LPS stimulation. Bub1 insufficiency attenuates TF expression and reduces TM suppression by blocking Akt and JNK phosphorylation, respectively, thus leading to the prevention of ARF and death caused by sepsis.

TGFBR2 mediated phosphorylation of BUB1 at Ser-318 is required for transforming growth factor-β signaling

BUB1 (budding uninhibited by benzimidazoles-1) is required for efficient TGF-β signaling, through its role in stabilizing the TGFBR1 and TGFBR2 complex. Here we demonstrate that TGFBR2 phosphorylates BUB1 at Serine-318, which is conserved in primates. S318 phosphorylation abrogates the interaction of BUB1 with TGFBR1 and SMAD2. Using BUB1 truncation domains (1–241, 241–482 and 482–723), we demonstrate that multiple contact points exist between BUB1 and TGF-β signaling components and that these interactions are independent of the BUB1 tetratricopeptide repeat (TPR) domain. Moreover, substitutions in the middle domain (241–482) encompassing S318 reveals that efficient interaction with TGFBR2 occurs only in its dephosphorylated state (241–482 S318A). In contrast, the phospho-mimicking mutant (241–482 S318D) exhibits efficient binding with SMAD2 and its over-expression results in a decrease in TGFBR1-TGFBR2 and TGFBR1-SMAD2 interactions. These findings suggest that TGFBR2 mediated BUB1 phosphorylation at S318 may serve as a switch for the dissociation of the SMAD2-TGFBR complex, and therefore represents a regulatory event for TGF-β signaling. Finally, we provide evidence that the BUB1-TGF-β signaling axis may mediate aggressive phenotypes in a variety of cancers.

Attenuation of Angiotensin II-Induced Hypertension in BubR1 Low-Expression Mice Via Repression of Angiotensin II Receptor 1 Overexpression

Background Angiotensin II (Ang II) can cause hypertension and tissue impairment via AGTR1 (Ang II receptor type 1), particularly in renal proximal tubule cells, and can cause DNA damage in renal cells via nicotinamide adenine dinucleotide phosphate oxidase. BubR1 (budding uninhibited by benzimidazole-related 1) is a multifaceted kinase that functions as a mitotic checkpoint. BubR1 expression can be induced by Ang II in smooth muscle cells in vitro, but the relationship between systemic BubR1 expression and the Ang II response is unclear. Methods and Results Twenty 24-week-old male BubR1 low-expression mice (BubR1^L/L mice) and age-matched BubR1^+/+ mice were used in this study. We investigated how Ang II stimulation affects BubR1^L/L mice. The elevated systolic blood pressure caused by Ang II stimulation in BubR1^+/+ mice was significantly attenuated in BubR1^L/L mice. Additionally, an attenuated level of Ang II-induced perivascular fibrosis was observed in the kidneys of BubR1^L/L mice. Immunohistochemistry revealed that the overexpression of AGTR1 induced by Ang II stimulation was repressed in BubR1^L/L mice. We evaluated AGTR1 and Nox-4 (nicotinamide adenine dinucleotide phosphate oxidase-4) levels to determine the role of BubR1 in the Ang II response. Results from in vitro assays of renal proximal tubule cells suggest that treatment with small interfering RNA targeting BubR1 suppressed Ang II-induced overexpression of AGTR1. Similarly, the upregulation in Nox4 and Jun N-terminal kinase induced by Ang II administration was repressed by treatment with small interfering RNA targeting BubR1. Conclusions Ang II-induced hypertension is caused by AGTR1 overexpression in the kidneys via the upregulation of BubR1 and Nox4.

The expanding phenotypes of cohesinopathies: one ring to rule them all!

Preservation and development of life depend on the adequate segregation of sister chromatids during mitosis and meiosis. This process is ensured by the cohesin multi-subunit complex. Mutations in this complex have been associated with an increasing number of diseases, termed cohesinopathies. The best characterized cohesinopathy is Cornelia de Lange syndrome (CdLS), in which intellectual and growth retardations are the main phenotypic manifestations. Despite some overlap, the clinical manifestations of cohesinopathies vary considerably. Novel roles of the cohesin complex have emerged during the past decades, suggesting that important cell cycle regulators exert important biological effects through non-cohesion-related functions and broadening the potential pathomechanisms involved in cohesinopathies. This review focuses on non-cohesion-related functions of the cohesin complex, gene dosage effect, epigenetic regulation and TGF-β in cohesinopathy context, especially in comparison to Chronic Atrial and Intestinal Dysrhythmia (CAID) syndrome, a very distinct cohesinopathy caused by a homozygous Shugoshin-1 (SGO1) mutation (K23E) and characterized by pacemaker failure in both heart (sick sinus syndrome followed by atrial flutter) and gut (chronic intestinal pseudo-obstruction) with no intellectual or growth delay. We discuss the possible impact of SGO1 alterations in human pathologies and the potential impact of the SGO1 K23E mutation in the sinus node and gut development and functions. We suggest that the human phenotypes observed in CdLS, CAID syndrome and other cohesinopathies can inform future studies into the less well-known non-cohesion-related functions of cohesin complex genes. Abbreviations: AD: Alzheimer Disease; AFF4: AF4/FMR2 Family Member 4; ANKRD11: Ankyrin Repeat Domain 11; APC: Anaphase Promoter Complex; ASD: Atrial Septal Defect; ATRX: ATRX Chromatin Remodeler; ATRX: Alpha Thalassemia X-linked intellectual disability syndrome; BIRC5: Baculoviral IAP Repeat Containing 5; BMP: Bone Morphogenetic Protein; BRD4: Bromodomain Containing 4; BUB1: BUB1 Mitotic Checkpoint Serine/Threonine Kinase; CAID: Chronic Atrial and Intestinal Dysrhythmia; CDK1: Cyclin Dependent Kinase 1; CdLS: Cornelia de Lange Syndrome; CHD: Congenital Heart Disease; CHOPS: Cognitive impairment, coarse facies, Heart defects, Obesity, Pulmonary involvement, Short stature, and skeletal dysplasia; CIPO: Chronic Intestinal Pseudo-Obstruction; c-kit: KIT Proto-Oncogene Receptor Tyrosine Kinase; CoATs: Cohesin Acetyltransferases; CTCF: CCCTC-Binding Factor; DDX11: DEAD/H-Box Helicase 11; ERG: Transcriptional Regulator ERG; ESCO2: Establishment of Sister Chromatid Cohesion N-Acetyltransferase 2; GJC1: Gap Junction Protein Gamma 1; H2A: Histone H2A; H3K4: Histone H3 Lysine 4; H3K9: Histone H3 Lysine 9; HCN4: Hyperpolarization Activated Cyclic Nucleotide Gated Potassium and Sodium Channel 4;p HDAC8: Histone deacetylases 8; HP1: Heterochromatin Protein 1; ICC: Interstitial Cells of Cajal; ICC-MP: Myenteric Plexus Interstitial cells of Cajal; ICC-DMP: Deep Muscular Plexus Interstitial cells of Cajal; If: Pacemaker Funny Current; IP3: Inositol trisphosphate; JNK: C-Jun N-Terminal Kinase; LDS: Loeys-Dietz Syndrome; LOAD: Late-Onset Alzheimer Disease; MAPK: Mitogen-Activated Protein Kinase; MAU: MAU Sister Chromatid Cohesion Factor; MFS: Marfan Syndrome; NIPBL: NIPBL, Cohesin Loading Factor; OCT4: Octamer-Binding Protein 4; P38: P38 MAP Kinase; PDA: Patent Ductus Arteriosus; PDS5: PDS5 Cohesin Associated Factor; P-H3: Phospho Histone H3; PLK1: Polo Like Kinase 1; POPDC1: Popeye Domain Containing 1; POPDC2: Popeye Domain Containing 2; PP2A: Protein Phosphatase 2; RAD21: RAD21 Cohesin Complex Component; RBS: Roberts Syndrome; REC8: REC8 Meiotic Recombination Protein; RNAP2: RNA polymerase II; SAN: Sinoatrial node; SCN5A: Sodium Voltage-Gated Channel Alpha Subunit 5; SEC: Super Elongation Complex; SGO1: Shogoshin-1; SMAD: SMAD Family Member; SMC1A: Structural Maintenance of Chromosomes 1A; SMC3: Structural Maintenance of Chromosomes 3; SNV: Single Nucleotide Variant; SOX2: SRY-Box 2; SOX17: SRY-Box 17; SSS: Sick Sinus Syndrome; STAG2: Cohesin Subunit SA-2; TADs: Topology Associated Domains; TBX: T-box transcription factors; TGF-β: Transforming Growth Factor β; TGFBR: Transforming Growth Factor β receptor; TOF: Tetralogy of Fallot; TREK1: TREK-1 K(+) Channel Subunit; VSD: Ventricular Septal Defect; WABS: Warsaw Breakage Syndrome; WAPL: WAPL Cohesin Release Factor.

Repression of TGF-β Signaling in Breast Cancer Cells by miR-302/367 Cluster

Objective

Epigenetic alterations of the malignantly transformed cells have increasingly been regarded as an important event in the carcinogenic development. Induction of some miRNAs such as miR-302/367 cluster has been shown to induce reprogramming of breast cancer cells and exert a tumor suppressive role by induction of mesenchymal to epithelial transition, apoptosis and a lower proliferation rate. Here, we aimed to investigate the impact of miR-302/367 overexpression on transforming growth factor-beta (TGF-β) signaling and how this may contribute to tumor suppressive effects of miR-302/367 cluster.

Materials and Methods

In this experimental study, MDA-MB-231 and SK-BR-3 breast cancer cells were cultured and transfected with miR-302/367 expressing lentivector. The impact of miR-302/367 overexpression on several mediators of TGF-β signaling and cell cycle was assessed by quantitative real-time polymerase chain reaction (qPCR) and flow cytometry.

Results

Ectopic expression of miR-302/367 cluster downregulated expression of some downstream elements of TGF-β pathway in MDA-MB-231 and SK-BR-3 breast cancer cell lines. Overexpression of miR-302/367 cluster inhibited proliferation of the breast cancer cells by suppressing the S-phase of cell cycle which was in accordance with inhibition of TGF-β pathway.

Conclusion

TGF-β signaling is one of the key pathways in tumor progression and a general suppression of TGF-β mediators by the pleiotropically acting miR-302/367 cluster may be one of the important reasons for its anti-tumor effects in breast cancer cells.

Serine/threonine kinase BUB1 promotes proliferation and radio-resistance in glioblastoma

BUB1 (Budding uninhibited by benzimidazoles 1), a mitotic checkpoint serine/threonine kinase, has been linked in numerous cancers to pro-tumorigenic phenomena including elevation of cellular proliferation, tumor growth, metastatic potential, and poorer patient prognosis. However, the role of BUB1 in glioblastoma remains poorly investigated. In this study, clinical analyses determined significant enrichment of BUB1 in glioblastoma with direct correlation of elevated expression to poorer prognosis in glioma patients. Genetic inhibition of BUB1 in glioblastoma tumor cells via shRNA silencing diminished both proliferative ability and tumorigenicity in vitro and in vivo. Silencing of BUB1 was additionally determined to promote the cytotoxic effect of irradiation on glioblastoma tumor cells, and investigation of the underlying pathways revealed the roles of DNA mismatch repair, spliceosome and c-Myc pathways. Mechanistically, FOXM1 was determined to positively regulate transcription of BUB1 via direct promoter region binding. For validation, pharmacologic inhibition through administration of a BUB1 inhibitor demonstrated attenuated glioblastoma cellular proliferation in vitro as well as delayed tumor growth with prolonged survival in vivo. Collectively, this study demonstrates a novel therapeutic target for glioblastoma in the form of BUB1, which plays a pivotal role in GBM proliferative and radio-resistance capacities in a FOXM1-dependant manner.

Suppressive effect of exogenous miR-16 and miR-34a on tumorigenesis of breast cancer cells

Recent investigations have shown tumor-suppressive roles for miR-16 and miR-34a. They also share some features in regard to targeting cancer cell signaling pathways which they control. Therefore, in this study, we aimed to further scrutinize whether exogenous induction of mature miR-34a and miR-16 can collaborate in breast tumor suppression. MDA-MB-231 and SK-BR-3 human breast cancer cell lines were cultured and transfected twice with hsa-miR-16-5p and hsa-miR-34a-5p mimics individually or in combination. The cells were analyzed for apoptosis rate and cell cycle indices by flow cytometry. Also, the expression of several invasion and the epithelial-mesenchymal transition markers was evaluated at gene and protein levels by quantitative real-time polymerase chain reaction and western blot analysis, respectively. Assessment of invasiveness and migratory potential of the transfected cells was performed using three-dimensional spheroid formation and wound-healing assay, respectively. In both cell lines, miR-16 and miR-34a induced apoptosis and cell-cycle arrest and also suppressed invasion and migration. Some of these effects, like cell-cycle arrest and induction of apoptosis, were significantly higher when using both microRNAs than when using them individually for transfection of the cells. Our results are indicating that miR-16 and miR-34a can collaborate in breast tumor suppression.

The BUB3-BUB1 Complex Promotes Telomere DNA Replication

Telomeres and telomere-binding proteins form complex secondary nucleoprotein structures that are critical for genome integrity but can present serious challenges during telomere DNA replication. It remains unclear how telomere replication stress is resolved during S phase. Here, we show that the BUB3-BUB1 complex, a component in spindle assembly checkpoint, binds to telomeres during S phase and promotes telomere DNA replication. Loss of the BUB3-BUB1 complex results in telomere replication defects, including fragile and shortened telomeres. We also demonstrate that the telomere-binding ability of BUB3 and kinase activity of BUB1 are indispensable to BUB3-BUB1 function at telomeres. TRF2 targets BUB1-BUB3 to telomeres, and BUB1 can directly phosphorylate TRF1 and promote TRF1 recruitment of BLM helicase to overcome replication stress. Our findings have uncovered previously unknown roles for the BUB3-BUB1 complex in S phase and shed light on how proteins from diverse pathways function coordinately to ensure proper telomere replication and maintenance.

Inhibition of BUB1 Kinase by BAY 1816032 Sensitizes Tumor Cells toward Taxanes, ATR, and PARP Inhibitors In Vitro and In Vivo

PURPOSE

The catalytic function of BUB1 is required for chromosome arm resolution and positioning of the chromosomal passenger complex for resolution of spindle attachment errors and plays only a minor role in spindle assembly checkpoint activation. Here, we present the identification and preclinical pharmacologic profile of the first BUB1 kinase inhibitor with good bioavailability.

EXPERIMENTAL DESIGN

The Bayer compound library was screened for BUB1 kinase inhibitors and medicinal chemistry efforts to improve target affinity and physicochemical and pharmacokinetic parameters resulting in the identification of BAY 1816032 were performed. BAY 1816032 was characterized for kinase selectivity, inhibition of BUB1 signaling, and inhibition of tumor cell proliferation alone and in combination with taxanes, ATR, and PARP inhibitors. Effects on tumor growth in vivo were evaluated using human triple-negative breast xenograft models.

RESULTS

The highly selective compound BAY 1816032 showed long target residence time and induced chromosome mis-segregation upon combination with low concentrations of paclitaxel. It was synergistic or additive in combination with paclitaxel or docetaxel, as well as with ATR or PARP inhibitors in cellular assays. Tumor xenograft studies demonstrated a strong and statistically significant reduction of tumor size and excellent tolerability upon combination of BAY 1816032 with paclitaxel or olaparib as compared with the respective monotherapies.

CONCLUSIONS

Our findings suggest clinical proof-of-concept studies evaluating BAY 1816032 in combination with taxanes or PARP inhibitors to enhance their efficacy and potentially overcome resistance.

Molecular Signature of CAID Syndrome: Noncanonical Roles of SGO1 in Regulation of TGF-β Signaling and Epigenomics

BACKGROUND & AIMS

A generalized human pacemaking syndrome, chronic atrial and intestinal dysrhythmia (CAID) (OMIM 616201), is caused by a homozygous SGO1 mutation (K23E), leading to chronic intestinal pseudo-obstruction and arrhythmias. Because CAID patients do not show phenotypes consistent with perturbation of known roles of SGO1, we hypothesized that noncanonical roles of SGO1 drive the clinical manifestations observed.

METHODS

To identify a molecular signature for CAID syndrome, we achieved unbiased screens in cell lines and gut tissues from CAID patients vs wild-type controls. We performed RNA sequencing along with stable isotope labeling with amino acids in cell culture. In addition, we determined the genome-wide DNA methylation and chromatin accessibility signatures using reduced representative bisulfite sequencing and assay for transposase-accessible chromatin with high-throughput sequencing. Functional studies included patch-clamp, quantitation of transforming growth factor-β (TGF-β) signaling, and immunohistochemistry in CAID patient gut biopsy specimens.

RESULTS

Proteome and transcriptome studies converge on cell-cycle regulation, cardiac conduction, and smooth muscle regulation as drivers of CAID syndrome. Specifically, the inward rectifier current, an important regulator of cellular function, was disrupted. Immunohistochemistry confirmed overexpression of Budding Uninhibited By Benzimidazoles 1 (BUB1) in patients, implicating the TGF-β pathway in CAID pathogenesis. Canonical TGF-β signaling was up-regulated and uncoupled from noncanonical signaling in CAID patients. Reduced representative bisulfite sequencing and assay for transposase-accessible chromatin with high-throughput sequencing experiments showed significant changes of chromatin states in CAID, pointing to epigenetic regulation as a possible pathologic mechanism.

CONCLUSIONS

Our findings point to impaired inward rectifier potassium current, dysregulation of canonical TGF-β signaling, and epigenetic regulation as potential drivers of intestinal and cardiac manifestations of CAID syndrome. Transcript profiling and genomics data are as follows: repository URL: https://www.ncbi.nlm.nih.gov/geo; SuperSeries GSE110612 was composed of the following subseries: GSE110309, GSE110576, and GSE110601.

Bub1 Facilitates Virus Entry through Endocytosis in a Model of Drosophila Pathogenesis

In this work, we identify for the first time that the nuclear protein Bub1 (budding uninhibited by benzimidazoles 1), a highly conserved subunit of the kinetochore complex regulating chromosome congression, has a novel and important function on the cell membrane to facilitate the virus to enter host cells. Bub1 deficiency empowers the host to have the ability to resist viral infection in Drosophila and a human cell line. Bub1 is involved in the virus entry step through regulating endocytosis. The DCV capsid protein can recruit Bub1, and DCV infection can strengthen the interaction between Bub1 and a clathrin-dependent endocytosis component. The restricted entry of vesicular stomatitis virus (VSV) and Listeria monocytogenes in bub1-deficient flies and cell lines was also observed. Therefore, our data implicate a previously unknown function of Bub1 that can be hijacked by pathogens to facilitate their entry, and Bub1 may serve as a potential antiviral therapy target for limiting viral entry.

In order to establish productive infection and dissemination, viruses usually evolve a number of strategies to hijack and/or subvert the host defense systems. However, host factors utilized by the virus to facilitate infection remain poorly characterized. In this work, we found that Drosophila melanogaster deficient in budding uninhibited by benzimidazoles 1 (bub1), a highly conserved subunit of the kinetochore complex regulating chromosome congression (1), became resistant to Drosophila C virus (DCV) infection, evidenced in increased survival rates and reduced viral loads, compared to the wild-type control. Mechanistic analysis further showed that Bub1 also functioned in the cytoplasm and was essentially involved in clathrin-dependent endocytosis of DCV and other pathogens, thus limiting pathogen entry. DCV infection potentially had strengthened the interaction between Bub1 and the clathrin adaptor on the cell membrane. Furthermore, the conserved function of Bub1 was also verified in a mammalian cell line. Thus, our data demonstrated a previously unknown function of Bub1 that could be hijacked by pathogens to facilitate their infection and spread.

IMPORTANCE In this work, we identify for the first time that the nuclear protein Bub1 (budding uninhibited by benzimidazoles 1), a highly conserved subunit of the kinetochore complex regulating chromosome congression, has a novel and important function on the cell membrane to facilitate the virus to enter host cells. Bub1 deficiency empowers the host to have the ability to resist viral infection in Drosophila and a human cell line. Bub1 is involved in the virus entry step through regulating endocytosis. The DCV capsid protein can recruit Bub1, and DCV infection can strengthen the interaction between Bub1 and a clathrin-dependent endocytosis component. The restricted entry of vesicular stomatitis virus (VSV) and Listeria monocytogenes in bub1-deficient flies and cell lines was also observed. Therefore, our data implicate a previously unknown function of Bub1 that can be hijacked by pathogens to facilitate their entry, and Bub1 may serve as a potential antiviral therapy target for limiting viral entry.

Bioinformatics analysis of key differentially expressed genes in well and poorly differentiated endometrial carcinoma

Endometrial carcinoma (EC) is one of the most common gynecological malignancies. The malignant degree increases between grade (G)1 and G3, and EC of G3 usually presents a high recurrence rate and poor prognosis. Therefore, the present study aimed to examine the principal genes associated with the degree of differentiation in EC. The microarrays GSE17025, GSE24537 and GSE35784, representing data of Type I EC samples of G1 and G3, were downloaded from the Gene Expression Omnibus. The differentially expressed genes (DEGs) and differentially expressed micro (mi)RNAs (DEMs) were identified, followed by functional enrichment analyses and interaction network construction. In total, 83 upregulated and 130 downregulated DEGs with the same expression trends in two mRNA datasets were screened. The upregulated DEGs were primarily enriched in 'mitotic cell cycle process', 'cell cycle process' and 'mitotic cell cycle'; while the downregulated DEGs were enriched in 'cellular component assembly involved in morphogenesis', 'cell projection organization' and 'microtubule‑based movement'. From the protein‑protein interaction network, DNA topoisomerase IIα, kinesin family member 11, cyclin B1 and BUB1 mitotic checkpoint serine/threonine were identified as foremost hub genes. One module was extracted and involved in 'mitotic cell cycle process' and 'cell cycle process'. Based on the analysis of DEMs and the miRNA‑target regulatory network, miRNA‑9 may be the most important upregulated DEM, and the DEGs forkhead box P1 and cyclin E1 may serve vital roles in the differentiation of EC. In conclusion, principal genes were identified that may be determinants of the carcinogenesis of poorly differentiated EC, which may facilitate the examination of potential molecular mechanisms. These genes may additionally help identify candidate biomarkers and novel therapeutic targets for poorly differentiated EC.

A high-content EMT screen identifies multiple receptor tyrosine kinase inhibitors with activity on TGFβ receptor

An epithelial to mesenchymal transition (EMT) enables epithelial tumor cells to break out of the primary tumor mass and to metastasize. Understanding the molecular mechanisms driving EMT in more detail will provide important tools to interfere with the metastatic process. To identify pharmacological modulators and druggable targets of EMT, we have established a novel multi-parameter, high-content, microscopy-based assay and screened chemical compounds with activities against known targets. Out of 3423 compounds, we have identified 19 drugs that block transforming growth factor beta (TGFβ)-induced EMT in normal murine mammary gland epithelial cells (NMuMG). The active compounds include inhibitors against TGFβ receptors (TGFBR), Rho-associated protein kinases (ROCK), myosin II, SRC kinase and uridine analogues. Among the EMT-repressing compounds, we identified a group of inhibitors targeting multiple receptor tyrosine kinases, and biochemical profiling of these multi-kinase inhibitors reveals TGFBR as a thus far unknown target of their inhibitory spectrum. These findings demonstrate the feasibility of a multi-parameter, high-content microscopy screen to identify modulators and druggable targets of EMT. Moreover, the newly discovered "off-target" effects of several receptor tyrosine kinase inhibitors have important consequences for in vitro and in vivo studies and might beneficially contribute to the therapeutic effects observed in vivo.

Quantitative and Dynamic Imaging of ATM Kinase Activity by Bioluminescence Imaging

Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA damage response, including DNA double strand breaks (DSBs). ATM activation results in the initiation of a complex cascade of events facilitating DNA damage repair, cell cycle checkpoint control, and survival. Traditionally, protein kinases have been analyzed in vitro using biochemical methods (kinase assays using purified proteins or immunological assays) requiring a large number of cells and cell lysis. Genetically encoded biosensors based on optical molecular imaging such as fluorescence or bioluminescence have been developed to enable interrogation of kinase activities in live cells with a high signal to background. We have genetically engineered a hybrid protein whose bioluminescent activity is dependent on the ATM-mediated phosphorylation of a substrate. The engineered protein consists of the split luciferase-based protein complementation pair with a CHK2 (a substrate for ATM kinase activity) target sequence and a phospho-serine/threonine-binding domain, FHA2, derived from yeast Rad53. Phosphorylation of the serine residue within the target sequence by ATM would lead to its interaction with the phospho-serine-binding domain, thereby preventing complementation of the split luciferase pair and loss of reporter activity. Bioluminescence imaging of reporter-expressing cells in cultured plates or as mouse xenografts provides a quantitative surrogate for ATM kinase activity and therefore the cellular DNA damage response in a noninvasive, dynamic fashion.

MiR-490-5p Suppresses Cell Proliferation and Invasion by Targeting BUB1 in Hepatocellular Carcinoma Cells

OBJECTIVE

To verify that miR-490-5p could influence hepatocellular carcinoma (HCC) cells' proliferation, invasion, cycle, and apoptosis by targeting BUB1.

METHODS

Quantitative real time-PCR (QRT-PCR) was used to determine the miR-490-5p expression. Immunohistochemistry, qRT-PCR, and Western blot were employed to detect BUB1 and transforming growth factor-beta (TGFβ/Smad) signaling-related proteins expression in hepatic tissues and cells. The luciferase assay was used to confirm the targeting relationship between miR-490-5p and BUB1. The Cell Counting Kit-8, colony formation, Transwell invasion, scratch healing assays, and flow cytometry analysis were conducted to evaluate HCC cells proliferation, invasion, migration, and apoptosis alteration after transfection.

RESULTS

In HCC tissues and cells, lower expression of miR-490-5p was detected, while BUB1 was overexpressed than controls. The upregulation of miR-490-5p inhibited BUB1 expression and the overexpression of miR-490-5p or the under-expression of BUB1 inhibited HCC cells proliferation, migration, invasion, and increased the apoptosis rate.

CONCLUSION

MiR-490-5p could regulate TGFβ/Smad signaling pathways by inhibiting BUB1, which could then inhibit HCC cells proliferation, invasion, and migration as well as decrease cell viability and increase apoptosis.

Glioblastoma stem cells exploit the αvβ8 integrin-TGFβ1 signaling axis to drive tumor initiation and progression

Glioblastoma (GBM) is a primary brain cancer that contains populations of stem-like cancer cells (GSCs) that home to specialized perivascular niches. GSC interactions with their niche influence self-renewal, differentiation and drug resistance, although the pathways underlying these events remain largely unknown. Here, we report that the integrin αvβ8 and its latent transforming growth factor β1 (TGFβ1) protein ligand have central roles in promoting niche co-option and GBM initiation. αvβ8 integrin is highly expressed in GSCs and is essential for self-renewal and lineage commitment in vitro. Fractionation of β8^high cells from freshly resected human GBM samples also reveals a requirement for this integrin in tumorigenesis in vivo. Whole-transcriptome sequencing reveals that αvβ8 integrin regulates tumor development, in part, by driving TGFβ1-induced DNA replication and mitotic checkpoint progression. Collectively, these data identify the αvβ8 integrin-TGFβ1 signaling axis as crucial for exploitation of the perivascular niche and identify potential therapeutic targets for inhibiting tumor growth and progression in patients with GBM.

Impact of novel miR-145-3p regulatory networks on survival in patients with castration-resistant prostate cancer

BACKGROUND

Despite recent advancements, metastatic castration-resistant prostate cancer (CRPC) is not considered curative. Novel approaches for identification of therapeutic targets of CRPC are needed.

METHODS

Next-generation sequencing revealed 945-1248 miRNAs from each lethal mCRPC sample. We constructed miRNA expression signatures of CRPC by comparing the expression of miRNAs between CRPC and normal prostate tissue or hormone-sensitive prostate cancer (HSPC). Genome-wide gene expression studies and in silico analyses were carried out to predict miRNA regulation and investigate the functional significance and clinical utility of the novel oncogenic pathways regulated by these miRNAs in prostate cancer (PCa).

RESULTS

Based on the novel miRNA expression signature of CRPC, miR-145-5p and miR-145-3p were downregulated in CRPC. By focusing on miR-145-3p, which is a passenger strand and has not been well studied in previous reports, we showed that miR-145-3p targeted 4 key molecules, i.e., MELK, NCAPG, BUB1, and CDK1, in CPRC. These 4 genes significantly predicted survival in patients with PCa.

CONCLUSIONS

Small RNA sequencing for lethal CRPC and in silico analyses provided novel therapeutic targets for CRPC.

Omega-3 polyunsaturated fatty acids as a treatment strategy for nonalcoholic fatty liver disease

Obese and type 2 diabetic (T2DM) patients have a high prevalence of nonalcoholic fatty liver disease (NAFLD). NAFLD is a continuum of chronic liver diseases ranging from benign hepatosteatosis to nonalcoholic steatohepatitis (NASH), cirrhosis and primary hepatocellular cancer (HCC). Because of its strong association with the obesity epidemic, NAFLD is rapidly becoming a major public health concern worldwide. Surprisingly, there are no FDA approved NAFLD therapies; and current therapies focus on the co-morbidities associated with NAFLD, namely, obesity, hyperglycemia, dyslipidemia, and hypertension. The goal of this review is to provide background on the disease process, discuss human studies and preclinical models that have examined treatment options. We also provide an in-depth rationale for the use of dietary ω3 polyunsaturated fatty acid (ω3 PUFA) supplements as a treatment option for NAFLD. This focus is based on recent studies indicating that NASH patients and preclinical mouse models of NASH have low levels of hepatic C_20-22 ω3 PUFA. This decline in hepatic PUFA may account for the major phenotypic features associated with NASH, including steatosis, inflammation and fibrosis. Finally, our discussion will address the strengths and limitations of ω3 PUFA supplements use in NAFLD therapy.