Pleiotrophin enhances PDGFB-induced gliomagenesis through increased proliferation of neural progenitor cells

Expression of Anaplastic Lymphoma Kinase (ALK) in glioma and possible clinical correlations. A retrospective institutional study

BACKGROUND

Glioblastoma is considered the most aggressive primary brain tumor. Recurrence after treatment is a significant problem with a failed response to optimal treatment. The recurrence of GBM is linked to different cellular and molecular pathways. Nationwide, in Egypt, astrocytic tumors are the most commonly diagnosed CNS tumor. Anaplastic Lymphoma Kinase (ALK CD246) is an enzymatic protein (RTK) belonging to the insulin receptors superfamily.

METHODS

This is a retrospective study including sixty cases of astrocytic tumors (males = 40, mean age = 31.5), (females = 20, mean age = 37.77) obtained through collecting archived paraffin blocks of astrocytic tumor from the Pathology Department, Cairo University Faculty of Medicine during the period from January 2015 till January 2019. All cases were evaluated for ALK expression trying to find any clinical correlations with the clinical data.

RESULTS

Correlations were made using a scatterplot matrix correlogram. There was a significant correlation between tumor recurrence and ALK expression (r = 0.8, P < 0.01), and incidence of postoperative seizures (r = 0.8, P < 0.05), and between mean age and score tumor (r = 0.8, P < 0.05).

CONCLUSION

Expression of ALK was found to be abundant among high-grade gliomas and tumor recurrence rate was higher in ALK-positive patients. Further studies are needed to evaluate the potential use of ALK as a prognostic marker in cases of GBM.

A systematic review and meta-analysis on the differentiation of glioma grade and mutational status by use of perfusion-based magnetic resonance imaging

Background

Molecular characterization plays a crucial role in glioma classification which impacts treatment strategy and patient outcome. Dynamic susceptibility contrast (DSC) and dynamic contrast enhanced (DCE) perfusion imaging have been suggested as methods to help characterize glioma in a non-invasive fashion. This study set out to review and meta-analyze the evidence on the accuracy of DSC and/or DCE perfusion MRI in predicting IDH genotype and 1p/19q integrity status.

Methods

After systematic literature search on Medline, EMBASE, Web of Science and the Cochrane Library, a qualitative meta-synthesis and quantitative meta-analysis were conducted. Meta-analysis was carried out on aggregated AUC data for different perfusion metrics.

Results

Of 680 papers, twelve were included for the qualitative meta-synthesis, totaling 1384 patients. It was observed that CBV, ktrans, Ve and Vp values were, in general, significantly higher in IDH wildtype compared to IDH mutated glioma. Meta-analysis comprising of five papers (totaling 316 patients) showed that the AUC of CBV, ktrans, Ve and Vp were 0.85 (95%-CI 0.75–0.93), 0.81 (95%-CI 0.74–0.89), 0.84 (95%-CI 0.71–0.97) and 0.76 (95%-CI 0.61–0.90), respectively. No conclusive data on the prediction of 1p/19q integrity was available from these studies.

Conclusions

Future research should aim to predict 1p/19q integrity based on perfusion MRI data. Additionally, correlations with other clinically relevant outcomes should be further investigated, including patient stratification for treatment and overall survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-022-01230-7.

Pleiotrophin Expression and Actions in Pancreatic β-Cells

Pleiotrophin (PTN) is a heparin-binding cytokine that is widely expressed during early development and increases in maternal circulation during pregnancy.Aged PTN-deficient mice exhibit insulin resistance, suggesting a role in metabolic control. The objectives of this study were to determine if PTN is expressed in mouse pancreatic β-cells in young vs. adult animals, and its effects on DNA synthesis, β-cell gene expression and glucose-stimulated insulin secretion (GSIS). The Ptn gene was expressed in isolated fractions of young mouse β-cells, especially within immature β-cells with low glucose transporter 2 expression. Expression was retained in the adult pancreas but did not significantly change during pregnancy. PTN and its receptor, phosphotyrosine phosphatase-β/ζ, were also expressed in the proliferative INS1E β-cell line. Fluorescence immunohistochemistry showed that PTN peptide was present in islets of Langerhans in adult mice, associated predominantly with β-cells. The percentage of β-cells staining for PTN did not alter during mouse pregnancy, but intense staining was seen during β-cell regeneration in young mice following depletion of β-cells with streptozotocin. Incubation of INS1E cells with PTN resulted in an increased DNA synthesis as measured by Ki67 localization and increased expression of Pdx1 and insulin. However, both DNA synthesis and GSIS were not altered by PTN in isolated adult mouse islets. The findings show that Ptn is expressed in mouse β-cells in young and adult life and could potentially contribute to adaptive increases in β-cell mass during early life or pregnancy.

Uncovering a Key Role of ETS1 on Vascular Abnormality in Glioblastoma

Glioblastoma (GBM) is the most aggressive type of brain tumor. Microvascular proliferation and abnormal vasculature are the hallmarks of the GBM, aggravating disease progression and increasing patient morbidity. Here, we uncovered a key role of ETS1 on vascular abnormality in glioblastoma. ETS1 was upregulated in endothelial cells from human tumors compared to endothelial cells from paired control brain tissue. Knockdown of Ets1 in mouse brain endothelial cells inhibited cell migration and proliferation, and suppressed expression of genes associated with vascular abnormality in GBM. ETS1 upregulation in tumor ECs was dependent on TGFβ signaling, and targeting TGFβ signaling by inhibitor decreased tumor angiogenesis and vascular abnormality in CT-2A glioma model. Our results identified ETS1 as a key factor regulating tumor angiogenesis, and suggested that TGFβ inhibition may suppress the vascular abnormality driven by ETS1.

Advances in understanding the role of P-gp in doxorubicin resistance: Molecular pathways, therapeutic strategies, and prospects

P-glycoprotein (P-gp) is a drug efflux transporter that triggers doxorubicin (DOX) resistance. In this review, we highlight the molecular avenues regulating P-gp, such as Nrf2, HIF-1α, miRNAs, and long noncoding (lnc)RNAs, to reveal their participation in DOX resistance. These antitumor compounds and genetic tools synergistically reduce P-gp expression. Furthermore, ATP depletion impairs P-gp activity to enhance the antitumor activity of DOX. Nanoarchitectures, including liposomes, micelles, polymeric nanoparticles (NPs), and solid lipid nanocarriers, have been developed for the co-delivery of DOX with anticancer compounds and genes enhancing DOX cytotoxicity. Surface modification of nanocarriers, for instance with hyaluronic acid (HA), can promote selectivity toward cancer cells. We discuss these aspects with a focus on P-gp expression and activity.

Neural G0: a quiescent-like state found in neuroepithelial-derived cells and glioma

Single‐cell RNA sequencing has emerged as a powerful tool for resolving cellular states associated with normal and maligned developmental processes. Here, we used scRNA‐seq to examine the cell cycle states of expanding human neural stem cells (hNSCs). From these data, we constructed a cell cycle classifier that identifies traditional cell cycle phases and a putative quiescent‐like state in neuroepithelial‐derived cell types during mammalian neurogenesis and in gliomas. The Neural G0 markers are enriched with quiescent NSC genes and other neurodevelopmental markers found in non‐dividing neural progenitors. Putative glioblastoma stem‐like cells were significantly enriched in the Neural G0 cell population. Neural G0 cell populations and gene expression are significantly associated with less aggressive tumors and extended patient survival for gliomas. Genetic screens to identify modulators of Neural G0 revealed that knockout of genes associated with the Hippo/Yap and p53 pathways diminished Neural G0 in vitro, resulting in faster G1 transit, down‐regulation of quiescence‐associated markers, and loss of Neural G0 gene expression. Thus, Neural G0 represents a dynamic quiescent‐like state found in neuroepithelial‐derived cells and gliomas.

1p/19q co-deletion status is associated with distinct tumor-associated macrophage infiltration in IDH mutated lower-grade gliomas

BACKGROUND

Tumor-associated macrophages (TAM)s are critical regulators of glioma progression. As yet, however, TAMs in isocitrate dehydrogenase (IDH) mutated lower-grade gliomas (LGGs) have not been thoroughly investigated. The aim of this study was to determine whether 1p/19q co-deletion status affects the TAM phenotype or its prevalence in IDH mutated LGGs.

METHODS

TAMs in IDH mutated LGGs were analyzed using transcriptome data from 230 samples in the TCGA database in combination with transcriptome data from single-cell RNA sequencing of IDH-mutated LGGs. Proteins potentially involved in TAM regulation were examined by immuno-staining in primary LGG samples harboring IDH mutations. Essential signaling pathways regulating TAM phenotypes were investigated in a glioma mouse model using small molecule inhibitors.

RESULTS

Most of the TAMs in IDH-mutated LGGs expressed the M1 activation markers CD86 and TNF, whereas a subset of individual TAMs co-expressed both M1 and M2-related markers. Bioinformatics analysis in combination with immuno-staining of IDH-mutated patient samples revealed higher amounts of TAMs expressing M2-related markers in 1p/19q non-codeletion IDH-mutated LGGs compared to 1p/19q codeletion LGGs. The levels of transforming growth factor beta 1 (TGFβ1) and macrophage colony-stimulating factor (M-CSF) were significantly higher in 1p/19q non-codeletion LGGs than in 1p/19q codeletion LGGs. M-CSF and TGFβ1 signal inhibition decreased tumor growth and modulated the TAM phenotype in a glioma mouse model.

CONCLUSIONS

Our data indicate that 1p/19q co-deletion status relates to distinct TAM infiltration in gliomas, which is likely mediated by M-CSF and TGFβ1 signaling. M-CSF and TGFβ1 signaling may play a pivotal role in regulating the TAM phenotype in glioma.

Assessment of PDGFRβ promoter methylation in canine osteosarcoma using methylation-sensitive high-resolution melting analysis

Platelet-derived growth factor signalling pathways play a fundamental role in inducing and sustaining the proliferative and prosurvival stimuli in canine osteosarcomas (cOSAs). The increased expression of platelet-derived growth factor receptors (PDGFRs) α and β, and their cognate ligands, were almost invariably observed in cOSAs and OSA-derived cell lines. In particular, overexpression of PDGFRβ-mediated signalling pathways was found in both the tumour microenvironment, where it drives stromal cell recruitment, and in neoangiogenesis, such as in tumour cells where it triggers aberrant proliferation, migration and local invasion. The majority of the pathological consequences of PDGFRβ signalling are because of aberrant expression. In fact, epigenetic dysregulation of oncogenes throughout demethylation of their promoter has emerged as a pivotal mechanism driving oncogenesis. The aim of this study was to assess the methylation status of the PDGFRβ promoter and to clarify its role in modulating the expression of the tyrosine kinase receptor in canine osteosarcoma. The CpG island of the PDGFRβ promoter was identified using a mixed in silico and experimental approach, and a method based upon the methylation-sensitive high-resolution melting assay for quantitatively and precisely assessing the methylation status of the promoter was then set up. The method herein described was then exploited to assess the methylation status of the promoter in a case series of cOSAa. COSAs consistently but variably expressed PDGFRβ. However, the promoter was almost completely demethylated, and its methylation status did not correlate with the expression levels. This finding supported the hypothesis that post-transcriptional regulatory mechanisms may act in cOSAs.

IDH mutation status is associated with distinct vascular gene expression signatures in lower-grade gliomas

Background

Vascular gene expression patterns in lower-grade gliomas (LGGs; diffuse World Health Organization [WHO] grades II–III gliomas) have not been thoroughly investigated. The aim of this study was to molecularly characterize LGG vessels and determine if tumor isocitrate dehydrogenase (IDH) mutation status affects vascular phenotype.

Methods

Gene expression was analyzed using an in-house dataset derived from microdissected vessels and total tumor samples from human glioma in combination with expression data from 289 LGG samples available in the database of The Cancer Genome Atlas. Vascular protein expression was examined by immunohistochemistry in human brain tumor tissue microarrays (TMAs) representing WHO grades II–IV gliomas and nonmalignant brain samples. Regulation of gene expression was examined in primary endothelial cells in vitro.

Results

Gene expression analysis of WHO grade II glioma indicated an intermediate stage of vascular abnormality, less severe than that of glioblastoma vessels but distinct from normal vessels. Enhanced expression of laminin subunit alpha 4 (LAMA4) and angiopoietin 2 (ANGPT2) in WHO grade II glioma was confirmed by staining of human TMAs. IDH wild-type LGGs displayed a specific angiogenic gene expression signature, including upregulation of ANGPT2 and serpin family H (SERPINH1), connected to enhanced endothelial cell migration and matrix remodeling. Transcription factor analysis indicated increased transforming growth factor beta (TGFβ) and hypoxia signaling in IDH wild-type LGGs. A subset of genes specifically induced in IDH wild-type LGG vessels was upregulated by stimulation of endothelial cells with TGFβ2, vascular endothelial growth factor, or cobalt chloride in vitro.

Conclusion

IDH wild-type LGG vessels are molecularly distinct from the vasculature of IDH-mutated LGGs. TGFβ and hypoxia-related signaling pathways may be potential targets for anti-angiogenic therapy of IDH wild-type LGG.

The role of PDGF-B/PDGFR-BETA axis in the normal development and carcinogenesis of the breast

PDGFs/PDGFRs axis is documented as an important tumor-promoting agent and potential therapeutic target for several human carcinomas, including breast cancer. However, little is known about the role played by the PDGF family members in the normal development of the breast tissue, breast carcinogenesis and tumor-microenvironment dynamics Despite its potent pro-lymphangiogenic effects, PDGF-B/PDGFR-beta axis remains controversial and incompletely elucidated in the field of breast cancer, with emphasis to its differential implications in breast cancer molecular subtypes. Although some data are available concerning this aspect, little or no information is found regarding the role of the PDGF-B/PDGFR-beta axis in rare and aggressive types of breast cancers, such as triple negative breast cancers (TNBCs) and its associated subtypes This review attempted to gather as many data as possible concerning PDGFs family members in the normal breast tissue and in breast carcinogenesis with special focus on their role in diagnosis and therapeutic approach.

Ptn functions downstream of C/EBPβ to mediate the effects of cAMP on uterine stromal cell differentiation through targeting Hand2 in response to progesterone

Ptn is a pleiotropic growth factor involving in the regulation of cellular proliferation and differentiation, but its biological function in uterine decidualization remains unknown. Here, we showed that Ptn was highly expressed in the decidual cells, and could induce the proliferation of uterine stromal cells and expression of Prl8a2 and Prl3c1 which were two well-established differentiation markers for decidualization, suggesting an important role of Ptn in decidualization. In the uterine stromal cells, progesterone stimulated the expression of Ptn accompanied with an accumulation of intracellular cAMP level. Silencing of Ptn impeded the induction of progesterone and cAMP on the differentiation of uterine stromal cells. Administration of PKA inhibitor H89 resulted in a blockage of progesterone on Ptn expression. Further analysis evidenced that regulation of progesterone and cAMP on Ptn was mediated by C/EBPβ. During in vitro decidualization, knockdown of Ptn could weaken the up-regulation of Prl8a2 and Prl3c1 elicited by C/EBPβ overexpression, while constitutive activation of Ptn reversed the repressive effects of C/EBPβ siRNA on the expression of Prl8a2 and Prl3c1. Meanwhile, Ptn might mediate the regulation of C/EBPβ on Hand2 which was a downstream target of Ptn in the differentiation of uterine stromal cells. Attenuation of Ptn or C/EBPβ by specific siRNA blocked the stimulation of Hand2 by progesterone and cAMP. Collectively, Ptn may play a vital role in the progesterone-induced decidualization pathway.

Pleiotrophin promotes chemoresistance to doxorubicin in osteosarcoma by upregulating P-glycoprotein

Chemoresistance is a major hindrance to successful treatment of osteosarcoma (OS). Pleiotrophin (PTN), a neurotrophic growth factor, has been linked to the malignant characteristics of various cancer types. We retrospectively examined the correlation between PTN expression and chemoresistance in OS in a cohort of 133 OS patients. Immunohistochemistry revealed that PTN expression correlated with the necrosis rate and local OS recurrence. In a prognostic analysis, high PTN expression was associated with poor overall and disease-free survival, and was an independent adverse prognostic factor for disease-free survival. In doxorubicin-treated OS cells, PTN knockdown enhanced cellular chemosensitivity, increased the apoptosis rate and inhibited clone formation, while PTN overexpression had the opposite effects. In a xenograft model, PTN knockdown and overexpression respectively enhanced and reduced cellular sensitivity to doxorubicin. PTN upregulated anaplastic lymphoma kinase (ALK), p-Glycogen Synthase Kinase (GSK)3β, β-catenin and multidrug resistance protein 1/P-glycoprotein (MDR1/P-gp). In rescue assays with the β-catenin inhibitor XAV939 and the MDR1/P-gp inhibitor verapamil, PTN promoted chemoresistance to doxorubicin in OS cells by activating ALK/GSK3β/β-catenin signaling, thereby upregulating MDR1/P-gp. Therefore, PTN could be used as a biomarker predicting chemotherapeutic responses, and downregulating PTN could be a promising therapeutic strategy to prevent chemoresistance in OS patients.