LOXL1-AS1 communicating with TIAR modulates vasculogenic mimicry in glioma via regulation of the miR-374b-5p/MMP14 axis

Long non-coding RNA LOXL1-AS1: a potential biomarker and therapeutic target in human malignant tumors

Long non-coding RNAs (lncRNAs) are transcripts that contain more than 200 nucleotides. Despite their inability to code proteins, multiple studies have identified their important role in human cancer through different mechanisms. LncRNA lysyl oxidase like 1 antisense RNA 1 (LOXL1-AS1), a newly discovered lncRNA located on human chromosome 15q24.1, has recently been shown to be involved in the occurrence and progression of various malignancies, such as colorectal cancer, gastric cancer, hepatocellular carcinoma, prostate cancer, non-small cell lung cancer, ovarian cancer, cervical cancer, breast cancer, glioma, thymic carcinoma, pancreatic carcinoma. LOXL1-AS1 acts as competitive endogenous RNA (ceRNA) and via sponging various miRNAs, including miR-374b-5p, miR-21, miR-423-5p, miR-589-5p, miR-28-5p, miR-324-3p, miR-708-5p, miR-143-3p, miR-18b-5p, miR-761, miR-525-5p, miR-541-3p, miR-let-7a-5p, miR-3128, miR-3614-5p, miR-377-3p and miR-1224-5p to promote tumor cell proliferation, invasion, migration, apoptosis, cell cycle, and epithelial-mesenchymal transformation (EMT). In addition, LOXL1-AS1 is involved in the regulation of P13K/AKT and MAPK signaling pathways. This article reviews the current understanding of the biological function and clinical significance of LOXL1-AS1 in human cancers. These findings suggest that LOXL1-AS1 may be both a reliable biomarker and a potential therapeutic target for cancers.

Potential role of lncRNA LOXL1-AS1 in human cancer development: a narrative review

Background and Objective

Long non-coding RNAs (lncRNAs) are a group of non-coding RNAs consisting of more than 200 nucleotides that are widely involved in various physiological and pathobiological processes in the body. LncRNA plays a crucial role in tumorigenesis and development with its unique functions, such as playing a role in a variety of biological processes of malignant tumors as a cancer-promoting factor or a cancer-suppressor factor. Lysyl oxidase-like protein 1-antisense RNA1 (LOXL1-AS1) is a novel functional lncRNA recently reported. This article reviews the current findings on the role of LOXL1-AS1 in cancer, and discusses the potential clinical significance and application prospects, in order to provide a theoretical basis and reference for the clinical diagnosis, treatment and screening of prognostic markers for malignant tumors.

Methods

The PubMed and Embase databases were searched using the keywords "cancer" or "tumor" or "neoplasm" and "LOXL1-AS1" for publications from 2018 to the present. The English literature was searched, with a focus on relevant articles. These articles validated the role and mechanism of LOXL1-AS1 in different cancers.

Key Content and Findings

LOXL1-AS1 is a recently reported novel lncRNA, which is abnormally expressed and upregulated in more than ten cancers, and is positively correlated with adverse clinical features and poor prognosis in cancer patients. LOXL1-AS1 competently binds to a variety of microRNAs to regulate the expression of downstream target genes and regulate related signaling pathways, including proliferation, migration, invasion and inhibition of malignant biological behaviors such as apoptosis.

Conclusions

LOXL1-AS1 is expected to become a novel biomarker for cancer diagnosis and treatment, with great potential as an independent prognostic indicator.

LOXL1-AS1 inhibits JAK2 ubiquitination and promotes cholangiocarcinoma progression through JAK2/STAT3 signaling

This study thoroughly investigated the role of the long non-coding RNA LOXL1-AS1 in the pathogenesis of cholangiocarcinoma (CCA). Through bioinformatics analysis and tissue samples validation, the study found that LOXL1-AS1 was significantly elevated in CCA, with its high expression closely tied to clinical pathological features and prognosis. In vitro and in vivo experiments revealed that LOXL1-AS1 was crucial in regulating CCA cell apoptosis, proliferation, migration, and invasion. Further investigations using FISH, subcellular localization experiments, RNA pull down, and RIP uncovered that LOXL1-AS1 primarily resided in the cytoplasm and influenced CCA progression by modulating the JAK2/STAT3 signaling pathway. Notably, LOXL1-AS1 might regulate the activity of JAK2 through modulating its ubiquitination and degradation. YY1 had also been found to act as an upstream transcription factor of LOXL1-AS1 to impact CCA cell malignancy. These findings shed light on the pivotal role of LOXL1-AS1 in CCA and offered potential directions for novel therapeutic strategies, providing a fresh perspective on tumor pathogenesis.

METTL3-mediated HOTAIRM1 promotes vasculogenic mimicry icontributionsn glioma via regulating IGFBP2 expression

BACKGROUND

HOTAIRM1 is revealed to facilitate the malignant progression of glioma. Vasculogenic mimicry (VM) is critically involved in glioma progression. Nevertheless, the molecular mechanism of HOTAIRM1 in regulating glioma VM formation remains elusive. Thus, we attempted to clarify the role and mechanism of HOTAIRM1 in VM formation in glioma.

METHODS

qRT-PCR and western blot assays were used to evaluate the gene and protein expression levels of HOTAIRM1 in glioma patient tissue samples and cell lines. The role of HOTAIRM1 in glioma cell progression and VM formation was explored using a series of function gain-and-loss experiments. RNA-binding protein immunoprecipitation (RIP), RNA pull-down, and mechanism experiments were conducted to assess the interaction between HOTAIRM1/METTL3/IGFBP2 axis. Furthermore, rescue assays were conducted to explore the regulatory function of HOTAIRM1/METTL3/IGFBP2 in glioma cell cellular processes and VM formation.

RESULTS

We found that HOTAIRM1 presented up-regulation in glioma tissues and cells and overexpression of HOTAIRM1 facilitated glioma cell proliferation, migration, invasion, and VM formation. Furthermore, overexpression of HOTAIRM1 promoted glioma tumor growth and VM formation capacity in tumor xenograft mouse model. Moreover, HOTAIRM1 was demonstrated to interact with IGFBP2 and positively regulated IGFBP2 expression. IGFBP2 was found to promote glioma cell malignancy and VM formation. Mechanistically, METTL3 was highly expressed in glioma tissues and cells and was bound with HOTAIRM1 which stabilized HOTAIRM1 expression. Rescue assays demonstrated that METTL3 silencing counteracted the impact of HOTAIRM1 on glioma cell malignancy and VM formation capacity.

CONCLUSION

HOTAIRM1, post-transcriptionally stabilized by METTL3, promotes VM formation in glioma via up-regulating IGFBP2 expression, which provides a new direction for glioma therapy.

A novel peptide P1-121aa encoded by STK24P1 regulates vasculogenic mimicry via ELF2 phosphorylation in glioblastoma

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system. Vasculogenic mimicry (VM) is a hematological system composed of tumor cells that exert blood perfusion without relying on vascular endothelial cells. The current poor results of anti-vascular therapy for clinical GBM are associated with the presence of VM; therefore, it is important to investigate VM formation in GBM. Our results demonstrate that STK24P1 encodes P1-121aa with a kinase structural domain, and in vitro kinase assays demonstrated that P1-121aa mediates modification of ELF2 phosphorylation. ChIP and dual luciferase reporter gene assays demonstrated that the transcription factor ELF2 binds to VE-cadherin and the VEGFR2 promoter region, thereby promoting VM formation in glioma cells. P1-121aa, encoded by the pseudogene STK24P1, phosphorylates ELF2 at S107, increasing the stability of the ELF2 protein. ELF2 promotes VEGFR2 and VE-cadherin expression at the transcriptional level, which in turn promotes VM in GBM. This study demonstrates the important roles of STK24P1, P1-121aa, and ELF2 in regulating VM in GBM, which could provide potential targets for GBM treatment.

Tumor-expressed B7-H3 promotes vasculogenic mimicry formation rather than angiogenesis in non-small cell lung cancer

BACKGROUND

Vasculogenic mimicry (VM), an alternative microvascular circulation independent of angiogenesis, is formed by aggressive cancer cells. Tumor-expressed B7-H3 has been reported to promote VM formation in hepatocellular carcinoma and modulate angiogenesis in breast cancer and colorectal cancer. However, its effects on VM generation and angiogenesis in non-small cell Lung cancer (NSCLC) remained to be elucidated.

METHODS

CRISPR/Cas9-mediated B7-H3 knockout (KO) was conducted in NSCLC A549 and H3255 cells. The expression of VM-related proteins, including vascular endothelial (VE)-cadherin and matrix metalloproteinase 14 (MMP14), and the secretion of vascular endothelial growth factor (VEGF) were measured by western blotting and chemiluminescence assay in both B7-H3 KO and mock-edited A549 and H3255 cells. To examine VM formation, a three-dimensional (3D) culture model was used for B7-H3 KO and mock A549 and H3255 cells. For in vivo analysis, xenograft mice models were established using B7-H3 KO and mock-edited A549 cells, and immunohistochemical (CD31) and histochemical (periodic acid-Schiff, PAS) double staining were performed to identify VM and endothelial vessels in tumor tissues. Finally, specific signaling inhibitors were used to analyze B7-H3-induced signaling pathway responsible for VE-cadherin and MMP14 expression and VM generation.

RESULTS

Higher expression of B7-H3 was associated with a worse prognosis and more advanced T-category in NSCLC. CRISPR/Cas9-mediated B7-H3 KO in A549 and H3255 cells led to decreased expression of VE-cadherin and MMP14; however, the secretion of VEGF by the two cell lines remained unchanged. In the 3D cell culture model, both B7-H3 KO A549 and H3255 cells showed a significant reduction in the formation of capillary-like tubular structures compared to mock-edited cells. In the in vivo xenograft model, mock-edited A549 cells formed excessive PAS⁺ CD31^- VM channels, while B7-H3 KO restrained VM formation in the xenograft tumors. However, no significant differences were found in CD31⁺ endothelial vessels between xenografts formed by B7-H3 KO and mock-edited A549 cells. Finally, we analyzed the signaling pathway responsible for B7-H3-induced VM formation and found that selective inhibition of the phosphoinositide 3-kinase(PI3K)/protein kinase B (AKT) hyperactivation by LY294002 was associated with decreased expression of MMP14 and VE-cadherin, and in vitro VM formation by both A549 and H3255 cells.

CONCLUSIONS

Tumor-expressed B7-H3 acts via PI3K/AKT signaling pathway to promote VM formation by NSCLC cells while bears no effects on angiogenesis in NSCLC.

LncRNA LOXL1-AS1 expression in cancer prognosis: A meta-analysis

BACKGROUND

Several studies showed that LncRNA LOXL1 antisense RNA 1 (LOXL1-AS1) is overexpressed in a variety of cancers and plays a role as an oncogene in cancer. The present meta-analysis aims to elucidate the relationship between LOXL1-AS1 expression and prognosis and clinicopathological features among cancer patients.

METHODS

PubMed, Web of Science, Cochrane Library, and EMBASE database were comprehensively and systematically searched. Pooled odds ratios (ORs) and hazard ratios with a 95% confidence interval (CI) were employed to assess the relationship between LOXL1-AS1 expression and clinical outcomes and clinicopathological features in cancer patients.

RESULTS

The present study finally enrolled 8 studies which included 657 cancer patients. The combined results indicated that the overexpression of LOXL1-AS1 was significantly associated with shorter overall survival (pooled hazard ratio = 1.99, 95% CI 1.49-2.65, P < .00001). Meanwhile, regarding clinicopathology of cancer patients, the upregulation of LOXL1-AS1 expression was closely related to lymph node metastasis (yes vs no OR = 4.01, 95% CI: 2.02-7.96, P < .0001) and distant metastasis (yes vs no OR = 3.04, 95% CI: 1.82-5.06, P < .0001), respectively.

CONCLUSION

High expression of LOXL1-AS1 in some cancers predicts shorter overall survival, distant metastasis, and lymph node metastasis. LOXL1-AS1 shows great promise as a prognostic biomarker in cancer patients.

Identification of Prognostic Signature of Necroptosis-Related lncRNAs and Molecular Subtypes in Glioma

Background

In tumor progression and epigenetic regulation, long non-coding RNA (lncRNA) and necroptosis are crucial regulators. However, in glioma microenvironment, the role of necroptosis-related lncRNAs (NRLs) remains unknown.

Method

In this study, the RNA-seq and clinical annotation of glioma patients were analyzed using the Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases. To investigate prognosis and tumor microenvironment of NRLs in gliomas, we conducted a prediction model based on the training cohort. The accuracy of the model was verified in the verification cohort.

Results

A signature composed of 13 NRLs was identified, and all glioma patients were divided into two groups. We found that each group has unique survival outcomes, biological behaviors, and immune infiltrating status. The necroptosis-related lncRNA signature (NRLS) model was found to be an independent risk factor in multivariate Cox analysis. Immunosuppressive microenvironment was positively correlated with the high-risk group. Due to significantly different IC50 between risk groups, NRLS could be used as a guide for chemotherapeutic treatment. Further, the entire cohort was divided into two clusters depending on NRLs. Consensus clustering method and the risk scoring system were basically similar. Survival probability was higher in Cluster 2, while Cluster 1 has stronger immunologic infiltration.

Conclusion

The predictive signature could be a prognostic factor independently and serve to detect the role of NRLs in glioma immunotherapy response.

T-Cell Intracellular Antigen 1-Like Protein in Physiology and Pathology

T-cell intracellular antigen 1 (TIA1)-related/like (TIAR/TIAL1) protein is a multifunctional RNA-binding protein (RBP) involved in regulating many aspects of gene expression, independently or in combination with its paralog TIA1. TIAR was first described in 1992 by Paul Anderson’s lab in relation to the development of a cell death phenotype in immune system cells, as it possesses nucleolytic activity against cytotoxic lymphocyte target cells. Similar to TIA1, it is characterized by a subcellular nucleo-cytoplasmic localization and ubiquitous expression in the cells of different tissues of higher organisms. In this paper, we review the relevant structural and functional information available about TIAR from a triple perspective (molecular, cellular and pathophysiological), paying special attention to its expression and regulation in cellular events and processes linked to human pathophysiology.

Immunotherapeutic Targeting of NG2/CSPG4 in Solid Organ Cancers

Neuro-glia antigen 2/chondroitin sulfate proteoglycan 4 (NG2/CSPG4, also called MCSP, HMW-MAA, MSK16, MCSPG, MEL-CSPG, or gp240) is a large cell-surface antigen and an unusual cell membrane integral glycoprotein frequently expressed on undifferentiated precursor cells in multiple solid organ cancers, including cancers of the liver, pancreas, lungs, and kidneys. It is a valuable molecule involved in cancer cell adhesion, invasion, spreading, angiogenesis, complement inhibition, and signaling. Although the biological significance underlying NG2/CSPG4 proteoglycan involvement in cancer progression needs to be better defined, based on the current evidence, NG2/CSPG4⁺ cells, such as pericytes (PCs, NG2⁺/CD146⁺/PDGFR-β⁺) and cancer stem cells (CSCs), are closely associated with the liver malignancy, hepatocellular carcinoma (HCC), pancreatic malignancy, and pancreatic ductal adenocarcinoma (PDAC) as well as poor prognoses. Importantly, with a unique method, we successfully purified NG2/CSPG4-expressing cells from human HCC and PDAC vasculature tissue blocks (by core needle biopsy). The cells appeared to be spheres that stably expanded in cultures. As such, these cells have the potential to be used as sources of target antigens. Herein, we provide new information on the possibilities of frequently selecting NG2/CSPG4 as a solid organ cancer biomarker or exploiting expressing cells such as CSCs, or the PG/chondroitin sulfate chain of NG2/CSPG4 on the cell membrane as specific antigens for the development of antibody- and vaccine-based immunotherapeutic approaches to treat these cancers.