Loss of endothelial programmed cell death 10 activates glioblastoma cells and promotes tumor growth

Shear stress and pathophysiological PI3K involvement in vascular malformations

Molecular characterization of vascular anomalies has revealed that affected endothelial cells (ECs) harbor gain-of-function (GOF) mutations in the gene encoding the catalytic α subunit of PI3Kα (PIK3CA). These PIK3CA mutations are known to cause solid cancers when occurring in other tissues. PIK3CA-related vascular anomalies, or "PIKopathies," range from simple, i.e., restricted to a particular form of malformation, to complex, i.e., presenting with a range of hyperplasia phenotypes, including the PIK3CA-related overgrowth spectrum. Interestingly, development of PIKopathies is affected by fluid shear stress (FSS), a physiological stimulus caused by blood or lymph flow. These findings implicate PI3K in mediating physiological EC responses to FSS conditions characteristic of lymphatic and capillary vessel beds. Consistent with this hypothesis, increased PI3K signaling also contributes to cerebral cavernous malformations, a vascular disorder that affects low-perfused brain venous capillaries. Because the GOF activity of PI3K and its signaling partners are excellent drug targets, understanding PIK3CA's role in the development of vascular anomalies may inform therapeutic strategies to normalize EC responses in the diseased state. This Review focuses on PIK3CA's role in mediating EC responses to FSS and discusses current understanding of PIK3CA dysregulation in a range of vascular anomalies that particularly affect low-perfused regions of the vasculature. We also discuss recent surprising findings linking increased PI3K signaling to fast-flow arteriovenous malformations in hereditary hemorrhagic telangiectasias.

Longitudinal Evaluation of DCE-MRI as an Early Indicator of Progression after Standard Therapy in Glioblastoma

Background and Purpose: Distinguishing treatment-induced imaging changes from progressive disease has important implications for avoiding inappropriate discontinuation of a treatment. Our goal in this study is to evaluate the utility of dynamic contrast-enhanced (DCE) perfusion MRI as a biomarker for the early detection of progression. We hypothesize that DCE-MRI may have the potential as an early predictor for the progression of disease in GBM patients when compared to the current standard of conventional MRI. Methods: We identified 26 patients from 2011 to 2023 with newly diagnosed primary glioblastoma by histopathology and gross or subtotal resection of the tumor. Then, we classified them into two groups: patients with progression of disease (POD) confirmed by pathology or change in chemotherapy and patients with stable disease without evidence of progression or need for therapy change. Finally, at least three DCE-MRI scans were performed prior to POD for the progression cohort, and three consecutive DCE-MRI scans were performed for those with stable disease. The volume of interest (VOI) was delineated by a neuroradiologist to measure the maximum values for Ktrans and plasma volume (Vp). A Friedman test was conducted to evaluate the statistical significance of the parameter changes between scans. Results: The mean interval between subsequent scans was 57.94 days, with POD-1 representing the first scan prior to POD and POD-3 representing the third scan. The normalized maximum Vp values for POD-3, POD-2, and POD-1 are 1.40, 1.86, and 3.24, respectively (FS = 18.00, p = 0.0001). It demonstrates that Vp max values are progressively increasing in the three scans prior to POD when measured by routine MRI scans. The normalized maximum Ktrans values for POD-1, POD-2, and POD-3 are 0.51, 0.09, and 0.51, respectively (FS = 1.13, p < 0.57). Conclusions: Our analysis of the longitudinal scans leading up to POD significantly correlated with increasing plasma volume (Vp). A longitudinal study for tumor perfusion change demonstrated that DCE perfusion could be utilized as an early predictor of tumor progression.

Novel Function of Cancer Stem Cell Marker ALDH1A3 in Glioblastoma: Pro-Angiogenesis through Paracrine PAI-1 and IL-8

Hyper-angiogenesis is a typical feature of glioblastoma (GBM), the most aggressive brain tumor. We have reported the expression of aldehyde dehydrogenase 1A3 (ALDH1A3) in proliferating vasculature in GBM patients. We hypothesized that ALDH1A3 may act as an angiogenesis promoter in GBM. Two GBM cell lines were lentivirally transduced with either ALDH1A3 (ox) or an empty vector (ev). The angiogenesis phenotype was studied in indirect and direct co-culture of endothelial cells (ECs) with oxGBM cells (oxGBMs) and in an angiogenesis model in vivo. Angiogenesis array was performed in oxGBMs. RT2-PCR, Western blot, and double-immunofluorescence staining were performed to confirm the expression of targets identified from the array. A significantly activated angiogenesis phenotype was observed in ECs indirectly and directly co-cultured with oxGBMs and in vivo. Overexpression of ALDH1A3 (oxALDH1A3) led to a marked upregulation of PAI-1 and IL-8 mRNA and protein and a consequential increased release of both proteins. Moreover, oxALDH1A3-induced angiogenesis was abolished by the treatment of the specific inhibitors, respectively, of PAI-1 and IL-8 receptors, CXCR1/2. This study defined ALDH1A3 as a novel angiogenesis promoter. oxALDH1A3 in GBM cells stimulated EC angiogenesis via paracrine upregulation of PAI-1 and IL-8, suggesting ALDH1A3-PAI-1/IL-8 as a novel signaling for future anti-angiogenesis therapy in GBM.

Exosomal miR-30a-5p promoted intrahepatic cholangiocarcinoma progression by increasing angiogenesis and vascular permeability in PDCD10 dependent manner

Tumor-associated angiogenesis positively associates with malignant metastasis of intrahepatic cholangiocarcinoma (ICCA). Cancer cell-derived exosomes carrying microRNAs involves in tumor microenvironment (TME) regulation. We aimed to evaluate exosomal miR-30a-5p in ICCA development. Our data showed that increased miR-30a-5p level was correlated with higher microvascular density (MVD) and worse prognosis. Augmented miR-30a-5p expression was induced by hypoxia induced factor 1α (HIF-1α) in ICCA cell. Further exploration revealed that ICCA-derived miR-30a-5p could be transferred to endothelial and increased endothelial cells recruitment and proliferation, induced angiogenesis and vascular permeability in exosome dependent manner. In addition, circulating exosomal miR-30a-5p was higher in ICCA patients, and correlated with ICCA tissues-expressing miR-30a-5p. Hypoxic stress enhanced the effects of exosomal miR-30a-5p on endothelial-associated phenotypes. Rescued experiments showed that exosomal miR-30a-5p modulated endothelial-associated phenotypes in a way relied on programmed cell death 10 (PDCD10). Moreover, we revealed that the packing of miR-30a-5p into ICCA cells-derived exosomes was mediated by eukaryotic translation initiation factor 4B (EIF4B). More importantly, the combined application of targeting miR-30a-5p and apatinib could synergistically improve antiangiogenic efficacy in ICCA. Combined, ICCA-derived exosomal miR-30a-5p could be an excellent therapeutic and monitoring indicator for ICCA patients.

Programmed cell death 10 increased blood-brain barrier permeability through HMGB1/TLR4 mediated downregulation of endothelial ZO-1 in glioblastoma

Dysfunction of blood brain barrier (BBB) contributes to the development of peritumoral edema (PTE) and GBM progression. Programmed cell death 10 (PDCD10) exerts various influence on cancers, especially in glioblastoma (GBM). We previously found that PDCD10 expression was positively correlated with PTE extent in GBM. Thus, the present study aims to investigate the emerging role of PDCD10 in regulating BBB permeability in GBM. Here we found that in vitro indirect co-culture of ECs with Pdcd10-overexpressed GL261 cells resulted in a significant increase of FITC-Dextran (MW, 4000) leakage by reducing endothelial zonula occluden-1 (ZO-1) and Claudin-5 expression in ECs respectively. Overexpression of Pdcd10 in GBM cells (GL261) triggered an increase of soluble high mobility group box 1 (HMGB1) release, which in turn activated endothelial toll like receptor 4 (TLR4) and downstream NF-κB, Erk1/2 and Akt signaling in ECs through a paracrine manner. Moreover, Pdcd10-overexpressed GL261 cells facilitated a formation of abnormal vasculature and increased the BBB permeability in vivo. Our present study demonstrates that upregulation of PDCD10 in GBM triggered HMGB1/TLR4 signaling in ECs and significantly decreased endothelial ZO-1 expression, which in turn dominantly increased BBB permeability and contributed to tumor progression in GBM.

A necroptosis-related lncRNA signature was identified to predict the prognosis and immune microenvironment of IDH-wild-type GBM

Introduction

Necroptosis-related genes are essential for the advancement of IDH-wild-type GBM. However, the putative effects of necroptosis-related lncRNAs (nrlncRNAs) in IDH-wild-type GBM remain unknown.

Methods

By using the TCGA and GTEx databases, a nrlncRNA prognostic signature was created using LASSO Cox regression. The median risk score was used to categorize the patients into low and high-risk groups. To confirm the validity, univariate, multivariate Cox regression and ROC curves were used. Furthermore, by enrichment analysis, immune correlation analysis, and drug sensitivity analysis, the targeted lncRNAs were selected for further verification. As the highest upregulated expression in tumor than peritumor specimens, RP11-131L12.4 was selected for phenotype and functional experiments in primary GBM cells.

Results

Six lncRNAs were proved to be closely related to necroptosis in IDH-1-wild-type GBM, which were used to create a new signature. For 1-, 2-, and 3-year OS, the AUCs were 0.709, 0.645 and 0.694, respectively. Patients in the low-risk group had a better prognosis, stronger immune function activity, and more immune cell infiltration. In contrast, enrichment analysis revealed that the malignant phenotype was more prevalent in the high-risk group. In vitro experiments indicated that RP11-131L12.4 increased the tumor proliferation, migration and invasion, but decreased the necroptosis. Moreover, this nrlncRNA was also proved to be negatively associated with patient prognosis.

Conclusion

The signature of nrlncRNAs may aid in the formulation of tailored and precise treatment for individuals with IDH-wild-type GBM. RP11-131L12.4 may play indispensable role in necroptosis suppression.

The Dual Role of PDCD10 in Cancers: A Promising Therapeutic Target

Programmed cell death 10 (PDCD10) was initially considered as a protein associated with apoptosis. However, recent studies showed that PDCD10 is actually an adaptor protein. By interacting with multiple molecules, PDCD10 participates in various physiological processes, such as cell survival, migration, cell differentiation, vesicle trafficking, cellular senescence, neurovascular development, and gonadogenesis. Moreover, over the past few decades, accumulating evidence has demonstrated that the aberrant expression or mutation of PDCD10 is extremely common in various pathological processes, especially in cancers. The dysfunction of PDCD10 has been strongly implicated in oncogenesis and tumor progression. However, the updated data seem to indicate that PDCD10 has a dual role (either pro- or anti-tumor effects) in various cancer types, depending on cell/tissue specificity with different cellular interactors. In this review, we aimed to summarize the knowledge of the dual role of PDCD10 in cancers with a special focus on its cellular function and potential molecular mechanism. With these efforts, we hoped to provide new insight into the future development and application of PDCD10 as a clinical therapeutic target in cancers.

Pan-Cancer Analysis on the Oncogenic Role of Programmed Cell Death 10

Purpose

Programmed cell death factor 10 (PDCD10) is associated with intercellular junction, cytoskeleton organization, cell proliferation, apoptosis, exocytosis, and angiogenesis. However, the role of PDCD10 in human cancer is unclear. This study aims to explore the role of PDCD10 in various tumors and its possible mechanism through bioinformatics analysis.

Methods

We verified the expression of the PDCD10 gene based on data from the ONCOMINE, TIMER2.0, and TISDB databases. The correlation of PDCD10 with prognosis of patients with different tumors was analyzed using data from the GEPIA2 database. Proteins bound to PDCD10 were analyzed from the STRING database. PDCD10, PDCD10-binding proteins, and associated candidate genes were analyzed in DAVID for functional and pathway analyses. We also evaluated the immunological, clinical, and genetic aspects of distinct cancers by using TIMER2.0 and the connection between PDCD10 expression and tumor immune subtypes by using TISDB. Single-cell sequencing data from the CancerSEA database were used to characterize cancer cell functional states and generate heat maps.

Results

PDCD10 overexpression is linked to certain molecular subtypes of human cancer. Low PDCD10 expression in patients with bladder urothelial carcinoma (BLCA), lung adenocarcinoma (LUAD), liver hepatocellular carcinoma (LIHC), adrenocortical carcinoma (ACC), head and neck squamous cell carcinoma (HNSC), kidney chromophobe carcinoma (KICH), brain lower grade glioma (LGG), pancreatic adenocarcinoma (PAAD), uterine corpus endometrial carcinoma (UCEC), oral squamous cell carcinoma (OSCC), and esophageal adenocarcinoma (ESAD) was correlated with favorable OS, whereas high PDCD10 expression in patients with LUSC, KIRC, READ, SKCM, and THYM was correlated with good prognosis. STRING network prediction results showed that 20 proteins, namely, paxillin (PXN), CCM2 scaffold protein (CCM2), TRAF3 interacting protein 3 (TRAF3IP3), FGFR1 oncogene partner 2 (FGFR1OP2), chromosome 4 open reading frame 19 (C4orf19), suppressor of IKBKE 1 (SIKE1), serine/threonine kinase 25 (STK25), striatin (STRN), protein phosphatase 2 catalytic subunit alpha (PPP2CA), mammalian sterile-20-like kinase 4 (MST4), MOB family member 4 (MOB4), protein phosphatase 2 scaffold subunit Abeta (PPP2R1B), sarcolemma-associated protein (SLMAP), serine/threonine kinase 24 (STK24), striatin 4 (STRN4), STRN3, protein phosphatase 2 scaffold subunit A alpha (PPP2R1A), striatin interacting protein 1 (STRIP1), CTTNBP2 N-terminal like (CTTNBP2NL), and cortactin binding protein 2 (CTTNBP2), can bind to PDCD10. Gene enrichment analysis suggested that PDCD10 is involved in the occurrence of different tumors through the Hippo signalling pathway, RNA transport, mRNA monitoring pathway, endocytosis, and T cell receptor signalling pathway. An inverse relationship was found between PDCD10 expression and cancer-associated fibroblasts in LUSC and TGCT, and PDCD10 expression was strongly connected with immunological subtypes, such as C1 (wound healing), C2 (interferon-gamma dominant), C3 (inflammation), C4 (lymphocyte depletion), C5 (immune silenced), and C6 (TGF-beta dominant). Finally, analysis of single-cell sequencing data revealed that PDCD10 expression is linked to epigenetic reprogramming, DNA repair, cell cycle progression, cell differentiation, inflammation, cell proliferation, cell differentiation, cell invasion, and angiogenesis.

Conclusion

The results of our investigation demonstrate that PDCD10 has an oncogenic function in many cancer types. This study provides a reference for future research on antitumor therapeutic targets.

Small Extracellular Vesicles and Their Involvement in Cancer Resistance: An Up-to-Date Review

In recent years, tremendous progress has been made in understanding the roles of extracellular vesicles (EVs) in cancer. Thanks to advancements in molecular biology, it has been found that the fraction of EVs called exosomes or small EVs (sEVs) modulates the sensitivity of cancer cells to chemotherapeutic agents by delivering molecularly active non-coding RNAs (ncRNAs). An in-depth analysis shows that two main molecular mechanisms are involved in exosomal modified chemoresistance: (1) translational repression of anti-oncogenes by exosomal microRNAs (miRs) and (2) lack of translational repression of oncogenes by sponging of miRs through long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). At the cellular level, these processes increase the proliferation and survival of cancer cells and improve their ability to metastasize and resist apoptosis. In addition, studies in animal models have shown enhancing tumor size under the influence of exosomal ncRNAs. Ultimately, exosomal ncRNAs are responsible for clinically significant chemotherapy failures in patients with different types of cancer. Preliminary data have also revealed that exosomal ncRNAs can overcome chemotherapeutic agent resistance, but the results are thoroughly fragmented. This review presents how exosomes modulate the response of cancer cells to chemotherapeutic agents. Understanding how exosomes interfere with chemoresistance may become a milestone in developing new therapeutic options, but more data are still required.

PDCD10 promotes proliferation, migration, and invasion of osteosarcoma by inhibiting apoptosis and activating EMT pathway

BACKGROUND

Osteosarcoma, a common primary malignant tumor, occurs in children and adolescents with a poor prognosis. The current treatment methods are various, while the five-year survival rate of patients has not been significantly improved. As a member of the programmed death factor (PDCD) family, programmed death factor 10 (PDCD10) plays a role in regulating cell apoptosis. Several studies of PDCD10 in CCM and cancers have been reported before. However, there are no relevant research reports on the effects of PDCD10 on osteosarcoma.

METHODS

We used bioinformatics analysis, IHC, and clinical data to confirm the expression of PDCD10 and its correlation with prognosis in osteosarcoma. Then, we used shRNAs and cDNA to knock down or overexpress PDCD10 in U2OS and MG63 cell lines. A series of function assays such as CCK8, Wound healing test, Plate cloning formation assay, and Transwell were done to confirm how PDCD10 affects osteosarcoma. Animal assays were done to confirm the conclusions in cell lines. At last, WB was used to measure the protein expression levels of apoptosis and the EMT pathway.

RESULTS

PDCD10 was highly expressed in patients with osteosarcoma and correlated with prognosis; PDCD10 knockdown inhibited osteosarcoma growth, proliferation, migration, and invasion; PDCD10 overexpression promoted osteosarcoma growth, proliferation, migration, and invasion. In vivo experiments confirmed the conclusions in cell lines; PDCD10 inhibited apoptosis and activated the EMT pathway.

CONCLUSIONS

In this study, it was found that PDCD10 was highly expressed in patients with osteosarcoma, and it was closely related to patient prognosis. PDCD10 inhibited tumor cell apoptosis and promoted tumor progression by activating the EMT pathway. These findings may provide a potential target for gene therapy of osteosarcoma.

Discovery of putative tumor suppressors from CRISPR screens reveals rewired lipid metabolism in acute myeloid leukemia cells

CRISPR knockout fitness screens in cancer cell lines reveal many genes whose loss of function causes cell death or loss of fitness or, more rarely, the opposite phenotype of faster proliferation. Here we demonstrate a systematic approach to identify these proliferation suppressors, which are highly enriched for tumor suppressor genes, and define a network of 145 such genes in 22 modules. One module contains several elements of the glycerolipid biosynthesis pathway and operates exclusively in a subset of acute myeloid leukemia cell lines. The proliferation suppressor activity of genes involved in the synthesis of saturated fatty acids, coupled with a more severe loss of fitness phenotype for genes in the desaturation pathway, suggests that these cells operate at the limit of their carrying capacity for saturated fatty acids, which we confirm biochemically. Overexpression of this module is associated with a survival advantage in juvenile leukemias, suggesting a clinically relevant subtype.

CRISPR-based knockout screens in cancer cells have suggested the existence of proliferation suppressor genes (PSG). Here, the authors develop an approach to systematically identify them, and reveal a PSG module involved in fatty acid synthesis and tumour suppression in acute myeloid leukemia cell lines.

The multifaceted PDCD10/CCM3 gene

The programmed cell death 10 (PDCD10) gene was originally identified as an apoptosis-related gene, although it is now usually known as CCM3, as the third causative gene of cerebral cavernous malformation (CCM). CCM is a neurovascular disease that is characterized by vascular malformations and is associated with headaches, seizures, focal neurological deficits, and cerebral hemorrhage. The PDCD10/CCM3 protein has multiple subcellular localizations and interacts with several multi-protein complexes and signaling pathways. Thus PDCD10/CCM3 governs many cellular functions, which include cell-to-cell junctions and cytoskeleton organization, cell proliferation and apoptosis, and exocytosis and angiogenesis. Given its central role in the maintenance of homeostasis of the cell, dysregulation of PDCD10/CCM3 can result in a wide range of altered cell functions. This can lead to severe diseases, including CCM, cognitive disability, and several types of cancers. Here, we review the multifaceted roles of PDCD10/CCM3 in physiology and pathology, with a focus on its functions beyond CCM.

Programmed cell death 10 promotes metastasis and epithelial-mesenchymal transition of hepatocellular carcinoma via PP2Ac-mediated YAP activation

Tumour metastasis is the main cause of postoperative tumour recurrence and mortality in patients with hepatocellular carcinoma (HCC), but the underlying mechanism remains unclear. Accumulating evidence has demonstrated that programmed cell death 10 (PDCD10) plays an important role in many biological processes. However, the role of PDCD10 in HCC progression is still elusive. In this study, we aimed to explore the clinical significance and molecular function of PDCD10 in HCC. PDCD10 is significantly upregulated in HCC, which also correlates with aggressive clinicopathological characteristics and predicts poor prognosis of HCC patients after liver resection. High PDCD10 expression promotes HCC cell proliferation, migration, and invasion in vitro and tumour growth, metastasis in vivo. In addition, PDCD10 could facilitate epithelial-to-mesenchymal transition (EMT) of HCC cells. In terms of the mechanism, PDCD10 directly binds to the catalytic subunit of protein phosphatase 2A (PP2Ac) and increases its enzymatic activity, leading to the interaction of YAP and dephosphorylation of the YAP protein. This interaction contributes to YAP nuclear translocation and transcriptional activation. PP2Ac is necessary for PDCD10-mediated HCC progression. Knocking down PP2Ac abolished the tumour-promoting role of PDCD10 in the migration, invasion and EMT of HCC. Moreover, a PP2Ac inhibitor (LB100) could restrict tumour growth and metastasis of HCC with high PDCD10 expression. Collectively, PDCD10 promotes EMT and the progression of HCC by interacting with PP2Ac to promote YAP activation, which provides new insight into the mechanism of cancer metastasis. PDCD10 may be a potential prognostic biomarker and therapeutic target for HCC.

Role of exosomal miRNA in chemotherapy resistance of Colorectal cancer: A systematic review

The third most common malignancy has been identified as Colorectal cancer (CRC) that conducive to death in most cases. Chemoresistance is a common obstacle to CRC treatment. Circulating exosomal microRNAs (miRNAs) have been shown to reverse chemo-resistance and are promising biomarkers for CRC. The capacity of engineered exosomes to cross biological barriers and deliver functional miRNAs could be used to achieve these proposes. The object of this review is the investigation of the role of exosomal miRNA in the chemo-resistance, diagnosis, and prognosis of CRC. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, electronic databases, PubMed, EMBASE, Web of Science, Scopus were searched from January 1990 to November 2020. Ultimately, eight articles included five in vitro (16 cell lines) and three in vivo examinations. Three studies demonstrated that increasing or decreasing mRNA expression was associated with increasing and decreasing cell proliferation in vitro. The presence of miRNA in two studies increased the sensitivity of the drug and exhibited a considerable growth inhibitory effect on cancer cell proliferation. The apoptotic rate was significantly increased in four studies by increased mRNA expression and reduced mrna expression. Tumor volume of xenograft models in three studies suppressed by antitumor miRNA activity. In contrast, anti-miRNA activity in one study decreased the tumor volume. Exosomal miRNAs can be regulators of chemo-resistance and predict adverse outcomes in CRC patients. In sum, exosomes containing miRNAs can be a promising biomarker for the prognosis and diagnosis of CRC. Subsequent research should be a focus on delineating the function of exosomal miRNA before clinical use.

Screening and identification of angiogenesis-related genes as potential novel prognostic biomarkers of hepatocellular carcinoma through bioinformatics analysis

Hepatocellular carcinoma (HCC) is a malignant tumor with high morbidity and mortality, which makes the prognostic prediction challenging. Angiogenesis appears to be of critical importance in the progression and metastasis of HCC. Some of the angiogenesis-related genes promote this process, while other anti-angiogenesis genes suppress tumor growth and metastasis. Therefore, the comprehensive prognostic value of multiple angiogenesis-related genes in HCC needs to be further clarified. In this study, the mRNA expression profile of HCC patients and the corresponding clinical data were acquired from multiple public databases. Univariate Cox regression analysis was utilized to screen out differentially expressed angiogenesis-related genes with prognostic value. A multigene signature was established with the least absolute shrinkage and selection operator Cox regression in the Cancer Genome Atlas cohort, and validated through an independent cohort. The results suggested that a total of 16 differentially expressed genes (DEGs) were associated with overall survival (OS) and a 7-gene signature was constructed. The risk score of each patient was calculated using this signature, the median value of which was used to divide these patients into a high-risk group and a low-risk group. Compared with the low-risk group, the patients in the high-risk group had a poor prognosis. The risk score was an independent predictor for OS through multivariate Cox regression analysis. Then, unsupervised learning was used to verify the validity of this 7-gene signature. A nomogram by further integrating clinical information and the prognostic signature was utilized to predict prognostic risk and individual OS. Functional enrichment analyses demonstrated that these DEGs were enriched in the pathways of cell proliferation and mitosis, and the immune cell infiltration was significantly different between the two risk groups. In summary, a novel angiogenesis-related genes signature could be used to predict the prognosis of HCC and for targeted therapy.

CCM3 is a gatekeeper in focal adhesions regulating mechanotransduction and YAP/TAZ signalling

The YAP/TAZ transcriptional programme is not only a well-established driver of cancer progression and metastasis but also an important stimulator of tissue regeneration. Here we identified Cerebral cavernous malformations 3 (CCM3) as a regulator of mechanical cue-driven YAP/TAZ signalling, controlling both tumour progression and stem cell differentiation. We demonstrate that CCM3 localizes to focal adhesion sites in cancer-associated fibroblasts, where it regulates mechanotransduction and YAP/TAZ activation. Mechanistically, CCM3 and focal adhesion kinase (FAK) mutually compete for binding to paxillin to fine-tune FAK/Src/paxillin-driven mechanotransduction and YAP/TAZ activation. In mouse models of breast cancer, specific loss of CCM3 in cancer-associated fibroblasts leads to exacerbated tissue remodelling and force transmission to the matrix, resulting in reciprocal YAP/TAZ activation in the neighbouring tumour cells and dissemination of metastasis to distant organs. Similarly, CCM3 regulates the differentiation of mesenchymal stromal/stem cells. In conclusion, CCM3 is a gatekeeper in focal adhesions that controls mechanotransduction and YAP/TAZ signalling.

Programmed Cell Death 10 Mediated CXCL2-CXCR2 Signaling in Regulating Tumor-Associated Microglia/Macrophages Recruitment in Glioblastoma

Background

Programmed cell death 10 (PDCD10) plays a crucial role in regulating tumor phenotyping, especially in glioblastoma (GBM). Glioma-associated microglia/macrophages (GAMs) in tumor pathological microenvironment contribute to GBM progression. We previously found that the infiltration of GAMs was associated with PDCD10 expression in GBM patients. The present study aims to further explore the regulation of PDCD10 on GAMs in GBM.

Methods

Overexpression of PDCD10 in human- and murine-GBM cells was established by lentiviral transduction. Cell behaviors and polarization of primary microglia, microglia- and macrophage-like cells were investigated through indirect co-culture with GBM cells in vitro respectively. The PDCD10-induced release of chemokines was identified by a chemokine protein array. The cross-talk between GBM and microglia as well as macrophages was further studied using selective antagonist SB225002. Finally, an orthotopic homograft mouse model was employed to verify the results of in vitro experiments.

Results

Indirect co-culture with PDCD10-overexpressed GBM cells promoted proliferation and migration of microglia- and macrophage-like cells, and stimulated pro-tumorigenic polarization of primary microglia, microglia- and macrophage-like cells. Pdcd10-upregulated GBM cells triggered a nearly 6-fold increase of CXC motif chemokine ligand 2 (CXCL2) release, which in turn activated CXC chemokine receptor 2 (CXCR2) and downstream Erk1/2 and Akt signaling in primary microglia, microglia- and macrophage-like cells. The blockage of CXCR2 signaling with specific inhibitor (SB225002) abolished microglia- and macrophage-like cell migration induced by PDCD10-upregulated GBM cells. Moreover, Pdcd10-upregulated GL261 cells promoted GAMs recruitment and tumor growth in vivo.

Conclusion

Our study demonstrates that overexpression of PDCD10 in GBM recruits and activates microglia/macrophages, which in turn promotes tumor progression. CXCL2-CXCR2 signaling mediated by PDCD10 is potentially involved in the crosstalk between GBM cells and GAMs.

PDCD10-Deficiency Promotes Malignant Behaviors and Tumor Growth via Triggering EphB4 Kinase Activity in Glioblastoma

We previously reported an angiogenic and tumor-suppressor-like function of programmed cell death 10 (PDCD10) in glioblastoma (GBM). However, the underlying mechanism remains to be elucidated. We hypothesized that loss of PDCD10 activates GBM cells and tumor progression via EphB4. To this end, PDCD10 was knocked down in U87 and T98g by lentiviral mediated shRNA transduction (shPDCD10). GBM cell phenotype in vitro and tumor growth in a mouse xenograft model were investigated in presence or absence of the treatment with a specific EphB4 kinase inhibitor NVP-BHG712 (NVP). We demonstrated that knockdown of PDCD10 in GBM cells significantly upregulated the mRNA and protein expression of EphB4 accompanied by the activation of Erk1/2. EphB4 kinase activity, reflected by phospho-EphB4, significantly increased in shPDCD10 GBM cells, and in tumors derived from shPDCD10 GBM xenografts, which was abolished by the treatment with NVP. Furthermore, NVP treatment significantly suppressed PDCD10-knockdown mediated aggressive GBM cell phenotype in vitro and extensive tumor cell proliferation, the tumor neo-angiogenesis, and a quick progression of tumor formation in vivo. In summary, loss of PDCD10 activates GBM cells and promotes tumor growth via triggering EphB4. Targeting EphB4 might be an effective strategy particularly for the personalized therapy in GBM patients with PDCD10-deficiency.

Emerging roles of CCM genes during tumorigenesis with potential application as novel biomarkers across major types of cancers

Cerebral cavernous malformations (CCMs) are microvascular anomalies in the brain that result in increased susceptibility to stroke. Three genes have been identified as causes of CCMs: cerebral cavernous malformations 1 [(CCM1) also termed Krev interaction trapped 1 (KRIT1)], cerebral cavernous malformation 2 [(CCM2) also termed MGC4607] and cerebral cavernous malformation 3 [(CCM3) also termed programmed cell death 10 (PDCD10)]. It has been demonstrated that both CCM1 and CCM3 bind to CCM2 to form a CCM signaling complex (CSC) with which to modulate multiple signaling cascades. CCM proteins have been reported to play major roles in microvascular angiogenesis in human and animal models. However, CCM proteins are ubiquitously expressed in all major tissues, suggesting an unseen broader role of the CSC in biogenesis. Recent evidence suggests the possible involvement of the CSC complex during tumorigenesis; however, studies concerning this aspect are limited. This is the first report to systematically investigate the expression patterns of CCM proteins in major human tumors using real‑time quantitative PCR, RNA‑fluorescence in situ hybridization, immunohistochemistry and multicolor immunofluorescence imaging. Our data demonstrated that differential expression patterns of the CSC complex are correlated with certain types and grades of major human cancers, indicating the potential application of CCM genes as molecular biomarkers for clinical oncology. Our data strongly suggest that more efforts are needed to elucidate the role of the CSC complex in tumorigenesis, which may have enormous clinical potential for cancer diagnostic, prognostic and therapeutic applications.

Endothelial cell clonal expansion in the development of cerebral cavernous malformations

Cerebral cavernous malformation (CCM) is a neurovascular familial or sporadic disease that is characterised by capillary-venous cavernomas, and is due to loss-of-function mutations to any one of three CCM genes. Familial CCM follows a two-hit mechanism similar to that of tumour suppressor genes, while in sporadic cavernomas only a small fraction of endothelial cells shows mutated CCM genes. We reported that in mouse models and in human patients, endothelial cells lining the lesions have different features from the surrounding endothelium, as they express mesenchymal/stem-cell markers. Here we show that cavernomas originate from clonal expansion of few Ccm3-null endothelial cells that express mesenchymal/stem-cell markers. These cells then attract surrounding wild-type endothelial cells, inducing them to express mesenchymal/stem-cell markers and to contribute to cavernoma growth. These characteristics of Ccm3-null cells are reminiscent of the tumour-initiating cells that are responsible for tumour growth. Our data support the concept that CCM has benign tumour characteristics.

Cerebral cavernous malformation is a vascular disease characterized by capillary-venous cavernomas in the central nervous system. Here the authors show that cavernomas display benign tumor characteristics and originate from the clonal expansion of mutated endothelial progenitors which can attract surrounding wild-type cells, inducing their mesenchymal transition and leading to growth of the cavernoma.

Lentiviral Vectors as Tools for the Study and Treatment of Glioblastoma

Glioblastoma (GBM) has the worst prognosis among brain tumors, hence basic biology, preclinical, and clinical studies are necessary to design effective strategies to defeat this disease. Gene transfer vectors derived from the most-studied lentivirus-the Human Immunodeficiency Virus type 1-have wide application in dissecting GBM specific features to identify potential therapeutic targets. Last-generation lentiviruses (LV), highly improved in safety profile and gene transfer capacity, are also largely employed as delivery systems of therapeutic molecules to be employed in gene therapy (GT) approaches. LV were initially used in GT protocols aimed at the expression of suicide factors to induce GBM cell death. Subsequently, LV were adopted to either express small noncoding RNAs to affect different aspects of GBM biology or to overcome the resistance to both chemo- and radiotherapy that easily develop in this tumor after initial therapy. Newer frontiers include adoption of LV for engineering T cells to express chimeric antigen receptors recognizing specific GBM antigens, or for transducing specific cell types that, due to their biological properties, can function as carriers of therapeutic molecules to the cancer mass. Finally, LV allow the setting up of improved animal models crucial for the validation of GBM specific therapies.

First case of neutropenia and thrombocytopenia in the setting of cerebral cavernous malformation 3

Cerebral cavernous malformation 3 (CCM3) is a vascular malformation disorder causing brain slow-flow vascular parenchymal lesions. These lesions are the result of variants in the Programmed Cell Death Protein 10 (PDCD10) gene, located on 3q26.1. We report an 8-month-old patient who was presented with seizures and intracranial abscesses and was found to have a variant of PDCD10 on whole exome sequencing, representing, to our knowledge, the youngest case of CCM3 described in the literature. Her clinical course was complicated by the development of neutropenia, requiring granulocyte colony-stimulating factor, and thrombocytopenia, requiring intermittent platelet transfusions, with later development of B acute lymphoblastic leukemia 2 years after initial presentation. This case represents the first description in the literature of hematologic complications in the setting of CCM3. We hypothesize that these hematological manifestations are the result of alterations in the actin and microtubule cytoskeleton, affecting the process of hematopoiesis in a similar fashion to the documented effect of the PDCD10 variant on neuronal migration.

C18H17NO6 and Its Combination with Scutellarin Suppress the Proliferation and Induce the Apoptosis of Human Glioma Cells via Upregulation of Fas-Associated Factor 1 Expression

Background

Glioma is the most common malignant brain tumor and the patients are prone to poor prognosis. Due to limited treatments, new drug exploration has become a general trend. Therefore, the objective of this study is to investigate the effect of the new drugs C₁₈H₁₇NO₆ and its combination with Scutellarin on glioma cells and the underlying mechanism.

Method

U251 and LN229 cells were administrated with C₁₈H₁₇NO₆ and its combination with Scutellarin. The proliferation ability of glioma cells was determined by cell counting kit-8, plate clone formation assay, and EdU incorporation assay. The cell cycle and apoptosis detection were detected by flow cytometry. Moreover, TUNEL assay was also used for cell apoptosis analysis. Then, the transfer ability of cells was achieved through wound healing assay. Furthermore, polymerase chain reaction (PCR) test and western bolt analysis were used to detect the mRNA expression and protein expression, respectively. Lastly, immunofluorescence was for the purity identification of astrocyte.

Result

The results showed that, with the increasing dose of C₁₈H₁₇NO₆, the cell inhibition rate, the cells in G1 phase, and the apoptosis rate were gradually increased, but the clone number, proliferation rate, and the cells in G2 and S phases were gradually decreased in comparison with control group. However, with the increase of C₁₈H₁₇NO₆, the transferred rate of U251 and LN229 was not significantly augmented, expect that on U251 in C₁₈H₁₇NO₆ 5 μM group. In addition, Scutellarin 200 μM has little effect on proliferation, with the inhibition rate 10-20% and proliferation rate except U251 in Scutellarin 200 μM group similar to that in control group. Moreover, compared to control group, Scutellarin 300 μM increased the U251 cells in G2 and S phases and the apoptosis rate of LN229 but decreased the LN229 cells in G2 and S phases. Besides, in Scutellarin 200 μM group, the transfer ability of LN229 was inhibited, but not in U251. Furthermore, if C₁₈H₁₇NO₆ was combined with Scutellarin 200/300μM, the proliferation and transferred ability were suppressed and the apoptosis was elevated in LN229 cell in comparison with C₁₈H₁₇NO₆ alone. Dramatically, the combined effect on U251 was the exact opposite. Importantly, there was little toxicity on astrocyte under the dose of C₁₈H₁₇NO₆ and Scutellarin in the study. In molecular level, the mRNA and protein expression of Fas-associated factor 1 (FAF1) expression in U251 and LN229 were upregulated by C₁₈H₁₇NO₆ and its combination with Scutellarin, especially the protein expression.

Conclusion

C₁₈H₁₇NO₆ could efficiently suppress cell proliferation and induce cell apoptosis in glioma cells, and its combination with Scutellarin had a promoting effect, in which the underlying mechanism referred to the upregulation of Fas-associated factor 1.

Loss of programmed cell death 10 activates tumor cells and leads to temozolomide-resistance in glioblastoma

PURPOSE

Glioblastoma (GBM) is one of the most aggressive and incurable primary brain tumors. Identification of novel therapeutic targets is an urgent priority. Programmed cell death 10 (PDCD10), a ubiquitously expressed apoptotic protein, has shown a dual function in different types of cancers and in chemo-resistance. Recently, we reported that PDCD10 was downregulated in human GBM. The aim of this study was to explore the function of PDCD10 in GBM cells.

METHODS

PDCD10 was knocked down in three GBM cell lines (U87, T98g and LN229) by lentiviral-mediated shRNA transduction. U87 and T98g transduced cells were used for phenotype study and LN229 and T98g cells were used for apoptosis study. The role of PDCD10 in apoptosis and chemo-resistance was investigated after treatment with staurosporine and temozolomide. A GBM xenograft mouse model was used to confirm the function of PDCD10 in vivo. A protein array was performed in PDCD10-knockdown and control GBM cells.

RESULTS

Knockdown of PDCD10 in GBM cells promoted cell proliferation, adhesion, migration, invasion, and inhibited apoptosis and caspase-3 activation. PDCD10-knockdown accelerated tumor growth and increased tumor mass by 2.1-fold and led to a chemo-resistance of mice treated with temozolomide. Immunostaining revealed extensive Ki67-positive cells and less activation of caspase-3 in PDCD10-knockdown tumors. The protein array demonstrated an increased release of multiple growth factors from PDCD10-knockdown GBM cells.

CONCLUSIONS

Loss of programmed cell death 10 activates tumor cells and leads to temozolomide-resistance in GBM, suggesting PDCD10 as a potential target for GBM therapy.

EphB4 forward signalling mediates angiogenesis caused by CCM3/PDCD10-ablation

CCM3, also named as PDCD10, is a ubiquitous protein expressed in nearly all tissues and in various types of cells. It is essential for vascular development and post-natal vessel maturation. Loss-of-function mutation of CCM3 predisposes for the familial form of cerebral cavernous malformation (CCM). We have previously shown that knock-down of CCM3 stimulated endothelial angiogenesis via impairing DLL4-Notch signalling; moreover, loss of endothelial CCM3 stimulated tumour angiogenesis and promoted tumour growth. The present study was designed to further elucidate the inside signalling pathway involved in CCM3-ablation-mediated angiogenesis. Here we report for the first time that silencing endothelial CCM3 led to a significant up-regulation of EphB4 mRNA and protein expression and to an increased kinase activity of EphB4, concomitantly accompanied by an activation of Erk1/2, which was reversed by treatment with the specific EphB4 kinase inhibitor NVP-BHG712 (NVP), indicating that silencing CCM3 activates EphB4 kinase forward signalling. Furthermore, treatment with NVP rescued the hyper-angiogenic phenotype induced by knock-down of endothelial CCM3 in vitro and in vivo. Additional study demonstrated that the activation of EphB4 forward signalling in endothelial cells under basal condition and after CCM3-silence was modulated by DLL4/Notch signalling, relying EphB4 at downstream of DLL4/Notch signalling. We conclude that angiogenesis induced by CCM3-silence is mediated by the activation of EphB4 forward signalling. The identified endothelial signalling pathway of CCM3-DLL4/Notch-EphB4-Erk1/2 may provide an insight into mechanism of CCM3-ablation-mediated angiogenesis and could potentially contribute to novel therapeutic concepts for disrupting aberrant angiogenesis in CCM and in hyper-vascularized tumours.

Introduction to cerebral cavernous malformation: a brief review

The disease known as cerebral cavernous malformations mostly occurs in the central nervous system, and their typical histological presentations are multiple lumen formation and vascular leakage at the brain capillary level, resulting in disruption of the blood-brain barrier. These abnormalities result in severe neurological symptoms such as seizures, focal neurological deficits and hemorrhagic strokes. CCM research has identified ‘loss of function’ mutations of three ccm genes responsible for the disease and also complex regulation of multiple signaling pathways including the WNT/β-catenin pathway, TGF-β and Notch signaling by the ccm genes. Although CCM research is a relatively new and small scientific field, as CCM research has the potential to regulate systemic blood vessel permeability and angiogenesis including that of the blood-brain barrier, this field is growing rapidly. In this review, I will provide a brief overview of CCM pathogenesis and function of ccm genes based on recent progress in CCM research. [BMB Reports 2016; 49(5): 255-262]

Study of angiogenic signaling pathways in hemangioblastoma

Hemangioblastoma (HB) is mainly located in the brain and the spinal cord. The tumor is composed of two major components, namely neoplastic stromal cells and abundant microvessels. Thus, hyper-vascularization is the hallmark of this tumor. Despite the identification of germline and/or epigenetic mutations of Von Hippel Lindau (VHL) gene as an important pathogenic mechanism of HB, little is known about the molecular signaling involved in this highly vascularized tumor. The present study investigated the key players of multiple angiogenic signaling pathways including VEGF/VEGFR2, EphB4/EphrinB2, SDF1α/CXCR4 and Notch/Dll4 pathways in surgical specimens of 22 HB. The expression of key angiogenic factors was detected by RT² -PCR and Western blot. Immunofluorescent staining revealed the cellular localization of these proteins. We demonstrated a massive upregulation of mRNA levels of VEGF and VEGFR2, CXCR4 and SDF1α, EphB4 and EphrinB2, as well as the main components of Dll4-Notch signaling in HB. An increase in the protein expression of VEGF, CXCR4 and the core-components of Dll4-Notch signaling was associated with an activation of Akt and Erk1/2 and accompanied by an elevated expression of PCNA. Immuofluorescent staining revealed the expression of VEGF and CXCR4 in endothelial cells as well as in tumor cells. Dll4 protein was predominantly found in tumor cells, whereas EphB4 immunoreactivity was exclusively detected in endothelial cells. We conclude that multiple key angiogenic pathways were activated in HB, which may synergistically contribute to the abundant vascularization in this tumor. Identification of these aberrant pathways provides potential targets for a possible future application of anti-angiogenic therapy for this tumor, particularly when a total surgical resection becomes difficult due to the localization or multiplicity of the tumor.