Transcription factor YY1 mediates self-renewal of glioblastoma stem cells through regulation of the SENP1/METTL3/MYC axis.

Glioma is a primary brain tumor with limited treatment approaches and glioblastoma stem cells (GSCs) are manifested with the self-renewal capability and high tumorigenic capacity. This study was performed to investigate the regulatory effect of the SUMO-specific protease 1 (SENP1)/methyltransferase-like 3 (METTL3)/MYC axis on the self-renewal of GSCs mediated by transcription factor Yin Yang 1 (YY1). Following bioinformatics analysis and clinical and cellular experiments, we found that YY1 was highly expressed in GBM tissues and cells, while silencing its expression reduced the self-renewal ability of GSCs. Functionally, YY1 promoted the transcriptional expression of SENP1 by binding to the promoter region of SENP1, while the deSUMOase SENP1 facilitated the methylase activity of m6A through deSUMOylation of the methylase METTL3, thereby promoting the m6A modification of MYC mRNA via METL3 and promoting the expression of MYC. A nude mouse xenograft model of GBM was also constructed to examine the tumorigenicity of GSCs. The obtained findings demonstrated that YY1 promoted tumorigenicity of GSCs by promoting the expression of MYC in vivo. Conclusively, YY1 can transcriptionally upregulate the SUMOylase SENP1 and enhance the methylase activity of METTL3, resulting in the increased m6A modification level of MYC mRNA, thereby promoting the self-renewal of GSCs.

Reduced PTCH2 expression is associated with glioma development through its regulation of the PTEN/AKT signaling pathway.

Mutations in the human protein patched homolog (PTCH) gene have been demonstrated to be associated with cancer development in several types of malignancy. However, the underlying mechanism of PTCH-associated cancer development remains poorly understood, to the best of our knowledge. In the present study, the expression of PTCH2 in glioma tumor tissues from The Cancer Genome Atlas (TCGA) database and clinical patients with glioma were measured. Reduced expression levels of PTCH2 were observed in patients with glioma with poor prognose. In vitro, overexpression of PTCH2 significantly suppressed the proliferation and invasion of the glioma cell lines, LN229 and U87-MG. Mechanistically, PTCH2 upregulated the expression of tumor suppressor PTEN, thereby leading to the suppression of pro-survival AKT signals in glioma. Reduced expression of PTEN and enhanced expression of AKT promoted glioma development in vitro and in vivo. Blockade of PTCH2/AKT signals efficiently strengthened the anticancer effects of chemotherapy and prolonged the survival time in tumor-bearing mice, which provided a novel insight into potential treatment strategies for glioma in the clinic.

HOXA-AS2 contributes to regulatory T cell proliferation and immune tolerance in glioma through the miR-302a/KDM2A/JAG1 axis.

Long non-coding RNAs (lncRNAs) have been manifested to manipulate diverse biological processes, including tumor-induced immune tolerance. Thus, we aimed in this study to identify the expression pattern of lncRNA homeobox A cluster antisense RNA 2 (HOXA-AS2) in glioma and decipher its role in immune tolerance and glioma progression. We found aberrant upregulation of lncRNA HOXA-AS2, lysine demethylase 2A (KDM2A), and jagged 1 (JAG1) and a downregulation of microRNA-302a (miR-302a) in glioma specimens. Next, RNA immunoprecipitation, chromatin immunoprecipitation, and dual-luciferase reporter gene assay demonstrated that lncRNA HOXA-AS2 upregulated KDM2A expression by preventing miR-302a from binding to its 3'untranslated region. The functional experiments suggested that lncRNA HOXA-AS2 could promote regulatory T (Treg) cell proliferation and immune tolerance, which might be achieved through inhibition of miR-302a and activation of KDM2A/JAG1 axis. These findings were validated in a tumor xenograft mouse model. To conclude, lncRNA HOXA-AS2 facilitates KDM2A/JAG1 expression to promote Treg cell proliferation and immune tolerance in glioma by binding to miR-302a. These findings may aid in the development of novel antitumor targets.

Histone demethylase JMJD1C promotes the polarization of M1 macrophages to prevent glioma by upregulating miR-302a.

Glioma is regarded as an aggressive lethal primary brain tumor. Jumonji domain containing 1C (JMJD1C) is a H3K9 demethylase which participates in the progression of various tumors, but its specific function and underlying mechanism in glioma development remain undefined, which is the purpose of our work. We initially assessed JMJD1C expression in glioma tissues and cells using the assays of RT-qPCR and immunohistochemistry. Meanwhile, the H3K9 level at the microRNA (miR)-302a promoter region was measured by chromatin immunoprecipitation assay, while luciferase-based reporter assay was performed for validation of the binding affinity between miR-302a and methyltransferase-like 3 (METTL3). The effect of METTL3 on suppressor of cytokine signaling 2 (SOCS2) was subsequently analyzed by MeRIP-RT-qPCR. Finally, a xenograft tumor model was established in nude mice, followed by measurement of tumor-associated macrophages using flow cytometry. JMJD1C was poorly expressed in glioma tissues. Furthermore, JMJD1C increased miR-302a expression through promoting H3K9me1 demethylation at the miR-302a promoter region. miR-302a was identified to target METTL3, which could inhibit SOCS2 expression via m6A modification. JMJD1C promoted M1 macrophage polarization and suppressed the growth of glioma xenografts through the miR-302a/METTL3/SOCS2 axis both in vivo and in vitro. In conclusion, JMJD1C could enhance M1 macrophage polarization to inhibit the onset of glioma, bringing a new insight into the contribution of JMJD1C to the pathobiology of glioma, with possible implications for targeted therapeutic method.

Matrix stiffness promotes glioma cell stemness by activating BCL9L/Wnt/ß-catenin signaling.

Matrix stiffness is a key physical characteristic of the tumor microenvironment and correlates tightly with tumor progression. Here, we explored the association between matrix stiffness and glioma development. Using atomic force microscopy, we observed higher matrix stiffness in highly malignant glioma tissues than in low-grade/innocent tissues. In vitro and in vivo analyses revealed that culturing glioma cells on stiff polyacrylamide hydrogels enhanced their proliferation, tumorigenesis and CD133 expression. Greater matrix stiffness could obviously up-regulated the expression of BCL9L, thereby promoting the activation of Wnt/ß-catenin signaling and ultimately increasing the stemness of glioma cells. Inhibiting Wnt/ß-catenin signaling using gigantol consistently improved the anticancer effects of chemotherapy and radiotherapy in mice with subcutaneous glioma tumors. These findings demonstrate that a stiffer matrix increases the stemness of glioma cells by activating BCL9L/Wnt/ß-catenin signaling. Moreover, we have provided a potential strategy for clinical glioma treatment by demonstrating that gigantol can improve the effectiveness of traditional chemotherapy/radiotherapy by suppressing Wnt/ß-catenin signaling.

Remodeling cancer stemness by collagen/fibronectin via the AKT and CDC42 signaling pathway crosstalk in glioma.

Cancer development is a complex set of proliferative progression, which arises in most cases via multistep pathways associated with various factors, including the tumor microenvironment and extracellular matrix. However, the underlying mechanisms of cancer development remain unclear and this study aimed to explore the role of extracellular matrix in glioma progression. Methods: The expression of type I collagen and fibronectin in tumor tissues from glioma patients was examined by immunofluorescence staining. The correlations between collagen/fibronectin and glioma progression were then analyzed. A 3D collagen/fibronectin cultured system was established for tumor cells culture in vitro. Quantitative, real-time PCR and western blot were used to detect PI3K/ATK and CDC42 signals associated proteins expression in glioma. We used in vitro Cell Counting Kit-8, colony formation, and tumorigenesis assays to investigate the function of PI3K/AKT and CDC42 signals associated proteins. A xenograft glioma mice model was also used to study the anticancer effects of integrin inhibitor in vivo. Results: Our study demonstrated that type I collagen and fibronectin collaborate to regulate glioma cell stemness and tumor growth. In a 3D collagen/fibronectin culture model, glioma cells acquired tumorigenic potential and revealed strengthened proliferative characteristics. More significantly, collagen/fibronectin could facilitate the activation of PI3K/AKT/SOX2 and CDC42/YAP-1/NUPR1/Nestin signaling pathways via integrin αvß3, eliciting sustained tumor growth and cancer relapse. Combination of the integrin signaling pathway inhibitor and the chemotherapeutic agent efficiently suppressed glioma cell proliferation and tumorigenic ability. Conclusion: We demonstrated that type I collagen and fibronectin could collaborate to promote glioma progression through PI3K/AKT/SOX2 and CDC42/YAP-1/NUPR1/Nestin signaling pathways. Blockade of the upstream molecular integrin αvß3 revealed improved outcome in glioma therapy, which provide new insights for eradicating tumors and reducing glioma cancer relapse.

B7-H3 Regulates Glioma Growth and Cell Invasion Through a JAK2/STAT3/Slug-Dependent Signaling Pathway.

PURPOSE: The aim of this study was to explore the potential role of B7-H3 in malignant glioma progression and identify an innovative approach in clinical glioma therapy. METHODS: The protein expression of B7-H3 in high- and low-grade tumor tissues from glioma patients was assessed by immunohistochemistry. The proliferative and invasive ability of B7-H3-overexpressing or knockout glioma cells was analyzed in vitro and in vivo by CCK-8 assay and an orthotopic mouse glioma model, respectively. Activation of the JAK2/STAT3/Slug signaling pathway and epithelial-mesenchymal transition (EMT) was examined by Western blotting and immunofluorescence. The anticancer effects of napabucasin (NAP) and temozolomide (TMZ) were analyzed in an orthotopic mouse glioma model. RESULTS: The expression of B7-H3 was higher in high-grade than in low-grade tumor tissues from glioma patients. In line with this, overexpression of B7-H3 enhanced glioma cell proliferation, induced sustained glioma growth, and promoted glioma cell invasion in vitro and in vivo. Moreover, these effects were mediated through the activation of the JAK2/STAT3/Slug signaling pathway in B7-H3 overexpression glioma cells. We also found that B7-H3 induced EMT processes through downregulation of E-cadherin and upregulation of MMP-2/-9 expression, resulting in enhanced invasion of glioma cells. Finally, we show that the combination of NAP and TMZ significantly suppressed glioma growth and glioma cell invasion, both in vitro and in vivo. CONCLUSION: B7-H3 overexpression facilitated sustained glioma growth and promoted glioma cell invasion through a JAK2/STAT3/Slug-dependent signaling pathway. Application of the STAT3 inhibitor NAP significantly suppressed glioma growth and invasion, and has potential as a therapeutic strategy for the treatment of glioma.

Multi-syphilitic gummas in pituitary and cerebellopontine angle in a patient.

PURPOSE: Multi-syphilitic gummas in pituitary and cerebellopontine angle (CPA) are extremely rare and easily misdiagnosed especially in patients with antibiotic abuse. We write this paper for clinicians to better understanding of cerebral gumma. METHODS: We report a patient with syphilitic gummas in pituitary and left CPA. The definite diagnosis is made by histopathology after surgery. RESULTS: A 49-years-old woman suffered from headaches with tinnitus and hypoacusis in left ear. She was diagnosed with syphilis but untreated. There were no chancre and rashes in the course of disease. Syphilis serological tests were positive. Brain MRI found two masses located in the left CPA and hypophysial fossa. The two masses were removed successively. We found a large number of Treponemapallidum in paraffin-embedded specimens by immunohistochemical staining. CONCLUSIONS: Syphilitic gummas in pituitary and CPA are similar to benign or malignant brain tumors, easily leading to misdiagnosis. Gumma should be considered in differential diagnosis when a patient has unexplained nervous system symptoms or signs and imaging findings suggest intracranial mass in syphilis seropositive patients.

LIM and SH3 protein 1 induces glioma growth and invasion through PI3K/AKT signaling and epithelial-mesenchymal transition.

PURPOSE: This study investigated the underlying mechanism of LIM and SH3 protein 1 (LASP1)-induced malignant glioma growth and invasion. MATERIALS AND METHODS: We compared the expression of LASP1 in malignant glioma tumor tissues and low-grade glioma tissues by immunohistochemistry. We also compared LASP1 overexpression and LASP1 knockout glioma cell proliferation and invasion in vitro and in vivo. We detected activation of the PI3K/AKT signaling pathway and epithelial-mesenchymal transition (EMT) process in tumor cells by western blotting or immunofluorescence. Glioma-bearing mice were used to investigate the anticancer effects of PI3K/AKT inhibitors in combination with temozolomide. RESULTS: We observed the enhanced expression of LASP1 in malignant glioma tumor tissues compared to low-grade glioma tissues, and LASP1 overexpression in glioma cells revealed an elevated capability of proliferation and invasion in vitro and in vivo. LASP1 overexpression also facilitated PI3K/AKT signaling and the EMT process through the downstream transcription factor Snail, which resulted in the intensive invasion of cancer cells. We combined PI3K/AKT inhibitors and temozolomide to block the LASP1/PI3K/AKT/Snail signaling pathway, which dramatically enhanced tumor suppression and provides an innovative approach for clinical glioma treatment. CONCLUSION: LASP1 is upregulated in malignant glioma and facilitates glioma cell proliferation and invasion by activation the PI3K/AKT/Snail signaling pathway. Blockade of the PI3K/AKT signal efficiently enhanced the anticancer effects of chemotherapeutic agents, which provides an innovative target in glioma treatment.

LIM and SH3 protein 1 regulates cell growth and chemosensitivity of human glioblastoma via the PI3K/AKT pathway.

BACKGROUND: LIM and SH3 protein 1 (LASP1) is upregulated in several types of human cancer and implicated in cancer progression. However, the expression and intrinsic function of LASP1 in glioblastoma (GBM) remains unclear. METHOD: Oncomine and The Cancer Genome Atlas (TCGA) database was analyzed for the expression and clinical significance of LASP1 in GBM. LASP1 mRNA and protein level were measured by qRT-PCR and western blotting. The effect of LASP1 on GBM proliferation was examined by MTT assay and colony formation assay, the effect of LASP1 on sensitivity of Temozolomide was measured by flow cytometry and subcutaneous tumor model. The association between LASP1 and PI3K/AKT signaling was assessed by western blotting. RESULTS: Oncomine GBM dataset analysis indicated LASP1 is significantly upregulated in GBM tissues compared to normal tissues. GBM dataset from The Cancer Genome Atlas (TCGA) revealed that high LASP1 expression is related to poor overall survival. LASP1 mRNA and protein in clinical specimens and tumor cell lines are frequently overexpressed. LASP1 knockdown dramatically suppressed U87 and U251 cell proliferation. Silencing LASP1 potentiated cell chemosensitivity to temozolomide in vitro, LASP1 knockdown inhibited tumor growth and enhanced the therapeutic effect of temozolomide in vivo. TCGA dataset analysis indicated LASP1 was correlated with PI3K/AKT signaling pathway, and LASP1 deletion inhibited this pathway. Combination treatment with PI3K/AKT pathway inhibitor LY294002 dramatically accelerated the suppression effect of temozolomide. CONCLUSION: LASP1 may function as an oncogene in GBM and regulate cell proliferation and chemosensitivity in a PI3K/AKT-dependent mechanism. Thus, the LASP1/PI3K/AKT axis is a promising target and therapeutic strategy for GBM treatment.

Laminoplasty using the Posterior Midline Approach in the Treatment of C1-2 Spinal Tumors.

AIM: This study aimed to investigate the method and efficacy of vertebral reconstruction using the posterior midline approach (PMA) in the treatment of C1-2 spinal tumors. MATERIAL AND METHODS: Twenty-seven patients with C1-2 spinal tumors from the Affiliated Hospital of Luzhou Medical College, who underwent microsurgical tumor resection through an occipitocervical PMA and spinal reset-reconstruction from January 2007 to December 2013, were enrolled in the study. The clinical data and results of these patients were analyzed and summarized. RESULTS: All patients underwent a successful complete tumor resection, with no operative deaths. The postoperative pathological diagnoses were schwannoma, neurofibroma, and meningioma in 21, 1, and 5 cases, respectively. The follow-up period was 4-48 months. Postoperatively, 1 patient was independent in daily activities, and 26 patients were able to live and work normally. No significant change was found between preoperative and postoperative MRI sequences of the cervical spine, and no cervical instability and tumor recurrence had occurred. CONCLUSION: PMA is suitable as the preferred approach for resection of C1-2 spinal tumors, and the vertebral reconstruction maintains spinal stability.