Capillary morphogenesis protein 2 is a novel prognostic biomarker and plays oncogenic roles in glioma

Cancer-Associated Fibroblast Signature Can Predict Prognosis and Therapeutic Responses in Skin Cutaneous Melanoma

Skin cutaneous melanoma (SKCM) is a lethal skin cancer with a poor prognosis and limited response to immunotherapy. Cancer-associated fibroblasts (CAFs) are key contributors to tumor progression, therapy resistance, and immunosuppression. In this study, mRNA sequencing and clinical data from SKCM samples were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to evaluate the prognostic significance, therapeutic implications, and potential for enhancing immunotherapy through targeting CAFs in SKCM. A CAF-related risk model comprising nine genes was developed, revealing that patients classified as low-risk exhibited superior survival outcomes and increased sensitivity to immunotherapy. Spearman correlation analysis identified significant associations between the risk score and the sensitivity to 40 drugs, as well as resistance to 17 drugs. Additionally, CAFs were categorized into three distinct subgroups in SKCM, with antigen-presenting CAFs (apCAFs) notably suppressing the infiltration of anti-tumor immune cells and strongly correlating with poor prognosis. In summary, the CAF-related risk model offers a robust prognostic tool for SKCM, capable of predicting both survival outcomes and therapeutic sensitivity. Moreover, the pivotal role of apCAFs within the immune microenvironment suggests that targeting these cells may enhance the efficacy of immunotherapy.

Cancer-cell-derived GABA promotes β-catenin-mediated tumour growth and immunosuppression

Many cancers have an unusual dependence on glutamine. However, most previous studies have focused on the contribution of glutamine to metabolic building blocks and the energy supply. Here, we report that cancer cells with aberrant expression of glutamate decarboxylase 1 (GAD1) rewire glutamine metabolism for the synthesis of γ-aminobutyric acid (GABA)-a prominent neurotransmitter-in non-nervous tissues. An analysis of clinical samples reveals that increased GABA levels predict poor prognosis. Mechanistically, we identify a cancer-intrinsic pathway through which GABA activates the GABAB receptor to inhibit GSK-3β activity, leading to enhanced β-catenin signalling. This GABA-mediated β-catenin activation both stimulates tumour cell proliferation and suppresses CD8+ T cell intratumoural infiltration, such that targeting GAD1 or GABABR in mouse models overcomes resistance to anti-PD-1 immune checkpoint blockade therapy. Our findings uncover a signalling role for tumour-derived GABA beyond its classic function as a neurotransmitter that can be targeted pharmacologically to reverse immunosuppression.

Comprehensive omics analyses profile genesets related with tumor heterogeneity of multifocal glioblastomas and reveal LIF/CCL2 as biomarkers for mesenchymal subtype

Rationale: Around 10%-20% patients with glioblastoma (GBM) are diagnosed with more than one tumor lesions or multifocal GBM (mGBM). However, the understanding on genetic, DNA methylomic, and transcriptomic characteristics of mGBM is still limited.

Methods: In this study, we collected nine tumor foci from three mGBM patients followed by whole genome sequencing, whole genome bisulfite sequencing, RNA sequencing, and immunohistochemistry. The data were further examined using public GBM databases and GBM cell line.

Results: Analysis on genetic data confirmed common features of GBM, including gain of chr.7 and loss of chr.10, loss of critical tumor suppressors, high frequency of PDGFA and EGFR amplification. Through profiling DNA methylome of individual tumor foci, we found that promoter methylation status of genes involved in detection of chemical stimulus, immune response, and Hippo/YAP1 pathway was significantly changed in mGBM. Although both CNV and promoter methylation alteration were involved in heterogeneity of different tumor foci from same patients, more CNV events than promoter hypomethylation events were shared by different tumor foci, implying CNV were relatively earlier than promoter methylation alteration during evolution of different tumor foci from same mGBM. Moreover, different tumor foci from same mGBM assumed different molecular subtypes and mesenchymal subtype was prevalent in mGBM, which might explain the worse prognosis of mGBM than single GBM. Interestingly, we noticed that LIF and CCL2 was tightly correlated with mesenchymal subtype tumor focus in mGBM and predicted poor survival of GBM patients. Treatment with LIF and CCL2 produced mesenchymal-like transcriptome in GBM cells.

Conclusions: Together, our work herein comprehensively profiled multi-omics features of mGBM and emphasized that components of extracellular microenvironment, such as LIF and CCL2, contributed to the evolution and prognosis of tumor foci in mGBM patients.

Genetic deletion of CMG2 exacerbates systemic-to-pulmonary shunt-induced pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) secondary to congenital heart disease (CHD-PAH) with systemic-to-pulmonary shunt (SPS) is characterized by proliferative vascular remodeling. Capillary morphogenesis gene-2 (CMG2) plays a key role in cell proliferation and apoptosis. This study aimed to determine the role of CMG2 in the pathogenesis of SPS-induced PAH. CMG2 levels were significantly downregulated in pulmonary arterioles from patients with Eisenmenger syndrome and rats with SPS-induced PAH. CMG2 was highly expressed in several cells including human pulmonary arterial smooth muscle cells (HPASMCs). CMG2^-/- rats exhibited more severe PAH and pulmonary vascular remodeling than wild-type rats when exposed to SPS for 8 weeks. Overexpression of CMG2 significantly inhibited proliferation and promoted apoptosis of HPASMCs, while knockdown of CMG2 promoted cell proliferation and inhibited cell apoptosis. Next-generation sequencing and subsequent validation results suggested that PI3K-AKT was the most prominent signaling pathway regulated by differentially expressed genes (DEGs) in CMG2^-/- rat lungs. Our work identified a novel role for CMG2 in SPS-induced PAH based on the findings that CMG2 deficiency exacerbates SPS-induced vascular remodeling in the development of PAH, indicating that CMG2 might act as a potential target for the treatment of CHD-PAH.

Proteomic profiling of MIN6 cell-derived exosomes

Exosomes have been widely used in research on the early clinical diagnosis, prognosis and treatment of various cancers due to their features of small size (30-120 nm), non-immunogenicity and ability to cross biological barriers. However, few studies have investigated exosomes involved in metabolic diseases. Early studies have found that adipose tissue can be a source of exosomes regulating metabolism, but the related functions of exosomes secreted by other tissues in the regulation of metabolic diseases have not been determined. In addition, islets were found to be able to secrete miRNA via exosomes, suggesting that islet exosomes may be among the sources of exosomes involved in the regulation of metabolic diseases and that the relevant protein profiles have not been characterized to date. Therefore, identifying the protein contents of pancreatic β cell-derived exosomes would benefit further research investigating the protein functions and mechanisms associated with diabetes-related metabolic diseases. SIGNIFICANCE: Exosomes are emerging tools for investigating metabolic diseases in recent years, but little research has been done. In our work, functional identification of MIN6 cell-derived exosomal proteins and comparative analysis of islet β cell exosomal protein data from different cell lines or from different species revealed that exosomes secreted by islet β cells may be involved in the regulation of glucose metabolism. These results may suggest that intercellular communication induced by exosome transfer among tissues may account for the major reason of diabetic metabolic disorder. In addition, these results may provide a theoretical basis for the study of the physiological and pathological functions of islet β cell exosomes for the future studies.

EGFR-PKM2 signaling promotes the metastatic potential of nasopharyngeal carcinoma through induction of FOSL1 and ANTXR2

Nasopharyngeal carcinoma (NPC) is notorious for its aggressiveness and high metastatic potential. NPC patients with distant metastasis have a particularly poor prognosis; however, evaluating metastatic potential by expression profiles of primary tumors is challenging. This study aimed to investigate the association between activation of epidermal growth factor receptor (EGFR) signaling and NPC metastasis and the underlying mechanisms. We found an association between EGFR protein overexpression and intense EGFR immunostaining in NPC samples with advanced tumor node metastasis stage, clinical stage, and distant metastasis in NPC patients. Exogenous EGF stimulates NPC mobility and invasiveness in vitro. Activation of EGFR signaling prompted PKM2 translocation to the nucleus. Silencing either EGFR or PKM2 attenuates NPC cell aggressiveness in vitro and in vivo. Blocking EGFR signaling with cetuximab suppressed NPC cell invasiveness in vitro and metastatic potential in vivo. Comprehensive analyses of transcriptome profiles indicated that the EGFR-PKM2 axis activates a number of novel metastasis promoters, including F3, FOSL1, EPHA2, ANTXR2, and AKR1C2. Finally, we found that the metastasis-promoting function of the EGFR-PKM2 axis is dependent on nuclear PKM2 regulation of the transcription of metastasis-related genes, including FOSL1 and ANTXR2. Our study indicates that EGFR-PKM2 signaling promotes NPC cell invasion and metastasis through induction of FOSL1 and ANTXR2 and identifies EGFR as a promising biomarker for predicting the risk of distant metastasis.

Zyxin (ZYX) promotes invasion and acts as a biomarker for aggressive phenotypes of human glioblastoma multiforme

Glioblastoma multiforme (GBM) is characterized by highly invasive growth, which leads to extensive infiltration and makes complete tumor excision difficult. Since cytoskeleton proteins are related to leading processes and cell motility, and through analysis of public GBM databases, we determined that an actin-interacting protein, zyxin (ZYX), may involved in GBM invasion. Our own glioma cohort as well as the cancer genome atlas (TCGA), Rembrandt, and Gravendeel databases consistently showed that increased ZYX expression was related to tumor progression and poor prognosis of glioma patients. In vitro and in vivo experiments further confirmed the oncogenic roles of ZYX and demonstrated the role of ZYX in GBM invasive growth. Moreover, RNA-seq and mass-spectrum data from GBM cells with or without ZYX revealed that stathmin 1 (STMN1) was a potential target of ZYX. Subsequently, we found that both mRNA and protein levels of STMN1 were positively regulated by ZYX. Functionally, STMN1 not only promoted invasion of GBM cells but also rescued the invasion repression caused by ZYX loss. Taken together, our results indicate that high ZYX expression was associated with worse prognosis and highlighted that the ZYX-STMN1 axis might be a potential therapeutic target for GBM.

CCL8 secreted by tumor-associated macrophages promotes invasion and stemness of glioblastoma cells via ERK1/2 signaling

Tumor-associated macrophages (TAMs) constitute a large population of glioblastoma and facilitate tumor growth and invasion of tumor cells, but the underlying mechanism remains undefined. In this study, we demonstrate that chemokine (C-C motif) ligand 8 (CCL8) is highly expressed by TAMs and contributes to pseudopodia formation by GBM cells. The presence of CCL8 in the glioma microenvironment promotes progression of tumor cells. Moreover, CCL8 induces invasion and stem-like traits of GBM cells, and CCR1 and CCR5 are the main receptors that mediate CCL8-induced biological behavior. Finally, CCL8 dramatically activates ERK1/2 phosphorylation in GBM cells, and blocking TAM-secreted CCL8 by neutralized antibody significantly decreases invasion of glioma cells. Taken together, our data reveal that CCL8 is a TAM-associated factor to mediate invasion and stemness of GBM, and targeting CCL8 may provide an insight strategy for GBM treatment.

Novel sphingomyelin biomarkers for brain glioma and associated regulation research on the PI3K/Akt signaling pathway

Glioma is one of the most common malignant tumor types of the central nervous system. It is necessary to identify biomarkers and novel therapeutic targets for glioma. The purpose of the present study was to distinguish lipid biomarkers with differential expression patterns in glioma tissues and normal brain tissues by matrix assisted laser desorption/ionization (MALDI)-imaging and MALDI-time of flight (TOF)-mass spectrometry (MS). Additionally, identification of lipid biomarkers was performed to describe novel therapeutic targets for glioma treatment. A total of six tissues from three patients with glioma and three control patients with traumatic brain injury were analyzed using UltrafleXtreme MALDI-TOF/TOF. The expression levels of 15 lipid peaks were higher in the TBT samples compared with in the GBT samples. The expression levels of another 16 lipid peaks were higher in the GBT samples compared with in the TBT samples. 14 peaks were identified as sphingomyelins using MS/MS. Additional results were also obtained from experiments using the glioma cell line U373-MG. These results indicated that treatment with the drug desipramine (Desi) inhibited the accumulation of ceramide on the cell membranes of glioma U373-MG cells. Treatment with Desi inhibited the activation of insulin-like growth factor-1 receptor and inhibited the activation of proteins in the PI3K/Akt signaling pathway.

Converging physiological roles of the anthrax toxin receptors

The anthrax toxin receptors-capillary morphogenesis gene 2 (CMG2) and tumor endothelial marker 8 (TEM8)-were identified almost 20 years ago, although few studies have moved beyond their roles as receptors for the anthrax toxins to address their physiological functions. In the last few years, insight into their endogenous roles has come from two rare diseases: hyaline fibromatosis syndrome, caused by mutations in CMG2, and growth retardation, alopecia, pseudo-anodontia, and optic atrophy (GAPO) syndrome, caused by loss-of-function mutations in TEM8. Although CMG2 and TEM8 are highly homologous at the protein level, the difference in disease symptoms points to variations in the physiological roles of the two anthrax receptors. Here, we focus on the similarities between these receptors in their ability to regulate extracellular matrix homeostasis, angiogenesis, cell migration, and skin elasticity. In this way, we shed light on how mutations in these two related proteins cause such seemingly different diseases and we highlight the existing knowledge gaps that could form the focus of future studies.

Increased Soluble CMG2 Serum Protein Concentration is Associated with the Progression of Prostate Carcinoma

Prostate carcinoma (PCa) is one of the leading causes of cancer-related death in males, but biomarkers for the prognosis are rare. Capillary morphogenesis gene 2 (CMG2) is a modulator of extracellular matrix remodeling during angiogenesis. Four isoforms of CMG2 have been described so far, one secreted in the serum as soluble CMG2 (sCMG2). The aim of this study was to evaluate the sCMG2 serum concentrations in 179 PCa patients and 163 age-matched control subjects by ELISA and correlate it to clinical and demographic parameters. We observed that sCMG2 concentration is increased in the serum of PCa patients with metastases, while no significant differences in the concentrations were detected between the control subjects and patients with localized PCa. Furthermore, elevated sCMG2 concentrations were significantly associated with the highest T stage. Increased sCMG2 serum concentrations tended to be associated with a worsened overall and disease-specific survival of the PCa patients. In conclusion, sCMG2 may be an interesting additive biomarker for the prediction of the progression of PCa and the patients' outcome.

Targeting Anthrax Toxin Receptor 2 Ameliorates Endometriosis Progression

Rationale: Endometriosis is a highly prevalent gynecological disease in women of reproductive age that markedly reduces life quality and fertility. Unfortunately, there is no cure for this disease, which highlights that more efforts are needed to investigate the underlying mechanism for designing novel therapeutic regimens. This study aims to investigate druggable membrane receptors distinctively expressed in endometriotic cells. Methods: Bioinformatic analysis of public databases was employed to identify potential druggable candidates. Normal endometrial tissues and ectopic endometriotic lesions were obtained for the determination of target genes. Primary endometrial and endometriotic stromal cells as well as two different mouse models of endometriosis were used to characterize molecular mechanisms and therapeutic outcomes of endometriosis, respectively. Results: Anthrax toxin receptor 2 (ANTXR2) mRNA and protein are upregulated in the endometriotic specimens. Elevation of ANTXR2 promotes endometriotic cell adhesion, proliferation, and angiogenesis. Furthermore, hypoxia is the driving force for ANTXR2 upregulation via altering histone modification of ANTXR2 promoter by reducing the repressive mark, histone H3 lysine 27 (H3K27) trimethylation, and increasing the active mark, H3K4 trimethylation. Activation of ANTXR2 signaling leads to increased Yes-associated protein 1 (YAP1) nuclear translocation and transcriptional activity, which contributes to numerous pathological processes of endometriosis. Pharmacological blocking of ANTXR2 signaling not only prevents endometriotic lesion development but also causes the regression of established lesion. Conclusion: Taken together, we have identified a novel target that contributes to the disease pathogenesis of endometriosis and provided a potential therapeutic regimen to treat it.