Norepinephrine promotes glioma cell migration through up-regulating the expression of Twist1

PL-hMSC and CH-hMSC derived soluble factors inhibit proliferation but improve hGBM cell migration by activating TGF-β and inhibiting Wnt signaling

Glioblastoma multiforme (GBM) is one of the most common and aggressive brain tumors. GBM resists most chemotherapeutic agents, resulting in a high mortality rate in patients. Human mesenchymal stem cells (hMSCs), which are parts of the cancer stroma, have been shown to be involved in the development and progression of GBM. However, different sources of hMSCs might affect GBM cells differently. In the present study, we established hMSCs from placenta (PL-hMSC) and chorion (CH-hMSC) to study the effects of their released soluble factors on the proliferation, migration, invasion, gene expression, and survival of human GBM cells, U251. We found that the soluble factors derived from CH-hMSCs and PL-hMSCs suppressed the proliferation of U251 cells in a dose-dependent manner. In contrast, soluble factors derived from both hMSC sources increased U251 migration without affecting their invasive property. The soluble factors derived from these hMSCs decreased the expression levels of CyclinD1, E2Fs and MYC genes that promote GBM cell proliferation but increased the expression level of TWIST gene, which promotes EMT and GBM cell migration. The functional study suggests that both hMSCs might exert their effects, at least in part, by activating TGF-β and suppressing Wnt/β-catenin signaling in U251 cells. Our study provides a better understanding of the interaction between GBM cells and gestational tissue-derived hMSCs. This knowledge might be used to develop safer and more effective stem cell therapy that improves the survival and quality of life of patients with GBM by manipulating the interaction between hMSCs and GBM cells.

GLUT1-mediated microglial proinflammatory activation contributes to the development of stress-induced spatial learning and memory dysfunction in mice

BACKGROUND

Stress is a recognized risk factor for cognitive decline, which triggers neuroinflammation involving microglial activation. However, the specific mechanism for microglial activation under stress and affects learning and memory remains unclear.

METHODS

The chronic stress mouse model was utilized to explore the relationship between microglial activation and spatial memory impairment. The effect of hippocampal hyperglycemia on microglial activation was evaluated through hippocampal glucose-infusion and the incubation of BV2 cells with high glucose. The gain-and loss-of-function experiments were conducted to investigate the role of GLUT1 in microglial proinflammatory activation. An adeno-associated virus (AAV) was employed to specifically knockdown of GLUT1 in hippocampal microglia to assess its impact on stressed-mice.

RESULTS

Herein, we found that chronic stress induced remarkable hippocampal microglial proinflammatory activation and neuroinflammation, which were involved in the development of stress-related spatial learning and memory impairment. Mechanistically, elevated hippocampal glucose level post-stress was revealed to be a key regulator of proinflammatory microglial activation via specifically increasing the expression of microglial GLUT1. GLUT1 overexpression promoted microglial proinflammatory phenotype while inhibiting GLUT1 function mitigated this effect under high glucose. Furthermore, specific downregulation of hippocampal microglial GLUT1 in stressed-mice relieved microglial proinflammatory activation, neuroinflammation, and spatial learning and memory injury. Finally, the NF-κB signaling pathway was demonstrated to be involved in the regulatory effect of GLUT1 on microglia.

CONCLUSIONS

We demonstrate that elevated glucose and GLUT1 expression induce microglia proinflammatory activation, contributing to stress-associated spatial memory dysfunction. These findings highlight significant interplay between metabolism and inflammation, presenting a possible therapeutic target for stress-related cognitive disorders.

Chronic stress as an emerging risk factor for the development and progression of glioma

ABSTRACT

Gliomas tend to have a poor prognosis and are the most common primary malignant tumors of the central nervous system. Compared with patients with other cancers, glioma patients often suffer from increased levels of psychological stress, such as anxiety and fear. Chronic stress (CS) is thought to impact glioma profoundly. However, because of the complex mechanisms underlying CS and variability in individual tolerance, the role of CS in glioma remains unclear. This review suggests a new proposal to redivide the stress system into two parts. Neuronal activity is dominant upstream. Stress-signaling molecules produced by the neuroendocrine system are dominant downstream. We discuss the underlying molecular mechanisms by which CS impacts glioma. Potential pharmacological treatments are also summarized from the therapeutic perspective of CS.

β‑adrenergic receptor activation promotes the proliferation of HepG2 cells via the ERK1/2/CREB pathways

Primary liver cancer is one of the most frequently diagnosed malignant tumors seen in clinics, and typically exhibits aggressive invasive behaviors, a poor prognosis, and is associated with high mortality rates. Long-term stress exposure causes norepinephrine (NE) release and activates the β-Adrenergic receptor (β-AR), which in turn exacerbates the occurrence and development of different types of cancers; however, the molecular mechanisms of β-AR in liver cancer are not fully understood. In the present study, reverse transcription (RT)-PCR and RT-quantitative PCR showed that β-AR expression was upregulated in human liver cancer cells (HepG2) compared with normal liver cells (LO2). Moreover, NE treatment promoted the growth of HepG2 cells, which could be blocked by propranolol, a β-AR antagonist. Notably, NE had no significant effect on the migration and epithelial-mesenchymal transition in HepG2 cells. Further experiments revealed that NE increased the phosphorylation levels of the extracellular signal-regulated kinase 1/2 (ERK1/2) and cyclic adenosine monophosphate response element-binding protein (CREB), while inhibition of ERK1/2 and CREB activation significantly blocked NE-induced cell proliferation. In summary, the findings of the present study suggested that β-adrenergic receptor activation promoted the proliferation of HepG2 cells through ERK1/2/CREB signaling pathways.

Norepinephrine promotes neuronal apoptosis of hippocampal HT22 cells by up-regulating the expression of long non-coding RNA MALAT1

Stress is ever present in our modern, performance-oriented and demanding society, which causes adverse stress reactions of the body and affects health seriously. Chronic stress has been recognized as a significant risk factor leading to cognitive impairment, but the underlying mechanism is far from fully understood. Norepinephrine (NE), a pivotal stress-induced hormone, has been found to induce cell apoptosis. However, the function and the key downstream mediator of NE on the regulation of hippocampal neurons still need further exploration. In this study, we explored the role of NE in neuronal apoptosis and its association with MALAT1. Flow cytometry assay and automated western bot assay were carried out to evaluate the cell apoptosis. The data showed that the rate of apoptosis rate and the levels of apoptotic proteins (cleaved-Caspase3 and cleaved-PARP) were significantly increased in HT22 cells after a high dose of NE treatment, suggesting a facilitative role of NE on hippocampal neuronal apoptosis. Besides, a high level of NE up-regulated the expression of MALAT1 in HT22 cells. Then, a lentivirus expressing MALAT1 shRNA was constructed to investigate the role of MALAT1 in cell apoptosis and the results revealed that MALAT1 depletion decreased the cell apoptosis. Moreover, the knockdown of MALAT1 abolished the discrepancy in apoptosis between NE-treated cells and control cells. In conclusion, a high level of the stress-induced hormone NE promoted apoptosis of hippocampal neurons by elevating the expression of MALAT1. Our findings provide new experimental data supporting the epigenetic mechanisms in the regulation of stress response and may provide a potential therapeutic target for stress-related cognition dysfunction.

An overview of Twist1 in glioma progression and recurrence

Glioma cells are characterized by high migration ability, resulting in the aggressive growth of the tumors and poor prognosis of patients. Epithelial-to-mesenchymal transition (EMT) is one of the most important steps for tumor migration and metastasis and be elevated during glioma progression and recurrence. Twist1 is a basic helix-loop-helix transcription factor and a key transcription factor involved in the process of EMT. Twist1 is related to glioma mesenchymal change, invasion, heterogeneity, self-renewal of tumor stem cells, angiogenesis, etc., and may be used as a prognostic indicator and therapeutic target for glioma patients. This paper mainly reviews the structural characteristics, regulatory mechanisms, and apparent regulation of Twist1, as well as the roles of Twist1 during glioma progression and recurrence, providing new revelations for its use as a potential drug target and glioma treatment research.

Insights about circadian clock in glioma: From molecular pathways to therapeutic drugs

Glioma is characterized as the most aggressive brain tumor that occurred in the central nervous system. The circadian rhythm is an essential cyclic change system generated by the endogenous circadian clock. Current studies found that the circadian clock affects glioma pathophysiology. It is still controversial whether the circadian rhythm disruption is a cause or an effect of tumorigenesis. This review discussed the association between cell cycle and circadian clock and provided a prominent molecular theoretical basis for tumor therapy. We illustrated the external factors affecting the circadian clock including thermodynamics, hypoxia, post-translation, and microRNA, while the internal characteristics concerning the circadian clock in glioma involve stemness, metabolism, radiotherapy sensitivity, and chemotherapy sensitivity. We also summarized the molecular pathways and the therapeutic drugs involved in the glioma circadian rhythm. There are still many questions in this field waiting for further investigation. The results of glioma chronotherapy in sensitizing radiation therapy and chemotherapy have shown great therapeutic potential in improving clinical outcomes. These findings will help us further understand the characteristics of glioma pathophysiology.

PTBP3 promotes tumorigenesis of glioblastoma by stabilizing Twist1

•

PTBP3 is upregulated in GBM and predicts poor prognosis.

•

PTBP3 promotes proliferation, EMT, migration, and invasion of GBM.

•

PTBP3 stabilizes Twist1 by decreasing its ubiquitination and degradation.

Objective

Glioblastoma (GBM) is the most common malignancy tumor of central nervous system. PTBP3 was closely associated with the development of tumor. However, the function and molecular mechanism of PTBP3 in GBM is little known.

Methods

qPCR and immunoblotting were used to detect PTBP3 expression levels in glioma tissues and cells. CCK8, Edu, flow cytometry, wound healing, and transwell assays were used to examined the function of PTBP3 in GBM. qPCR, Immunoblotting, and ubiquitination assays were performed to identify the mechanism of PTBP3.

Results

We found that PTBP3 was upregulated in GBM, and high expression of PTBP3 correlated with the poor survival of GBM patients. PTBP3 knockdown reduced proliferation, invasion, and migration of GBM. Conversely, overexpressing PTBP3 has an opposite effect. Moreover, PTBP3 had an effect on the EMT of GBM. More importantly, we found that PTBP3 stabilized Twist1 by decreasing its ubiquitination and degradation. Furthermore, orthotopic xenograft models were used to demonstrate the PTBP3 on the development of GBM in vivo.

Conclusion

This study proved that PTBP3 promoted tumorigenesis of GBM by stabilizing Twist1, which provided a new therapeutic target for GBM.

TWIST1 methylation by SETD6 selectively antagonizes LINC-PINT expression in glioma

Gliomas are one of the most common and lethal brain tumors among adults. One process that contributes to glioma progression and recurrence is the epithelial to mesenchymal transition (EMT). EMT is regulated by a set of defined transcription factors which tightly regulate this process, among them is the basic helix-loop-helix family member, TWIST1. Here we show that TWIST1 is methylated on lysine-33 at chromatin by SETD6, a methyltransferase with expression levels correlating with poor survival in glioma patients. RNA-seq analysis in U251 glioma cells suggested that both SETD6 and TWIST1 regulate cell adhesion and migration processes. We further show that TWIST1 methylation attenuates the expression of the long-non-coding RNA, LINC-PINT, thereby promoting EMT in glioma. Mechanistically, TWIST1 methylation represses the transcription of LINC-PINT by increasing the occupancy of EZH2 and the catalysis of the repressive H3K27me3 mark at the LINC-PINT locus. Under un-methylated conditions, TWIST1 dissociates from the LINC-PINT locus, allowing the expression of LINC-PINT which leads to increased cell adhesion and decreased cell migration. Together, our findings unravel a new mechanistic dimension for selective expression of LINC-PINT mediated by TWIST1 methylation.