Evaluation of cytotoxicity of propofol and its related mechanism in glioblastoma cells and astrocytes

Propofol Protects the Blood-Brain Barrier After Traumatic Brain Injury by Stabilizing the Extracellular Matrix via Prrx1: From Neuroglioma to Neurotrauma

The purpose of this study is to explore the shared molecular pathogenesis of traumatic brain injury (TBI) and high-grade glioma and investigate the mechanism of propofol (PF) as a potential protective agent. By analyzing the Chinese glioma genome atlas (CGGA) and The Cancer Genome Atlas (TCGA) databases, we compared the transcriptomic data of high-grade glioma and TBI patients to identify common pathological mechanisms. Through bioinformatics analysis, in vitro experiments and in vivo TBI model, we investigated the regulatory effect of PF on extracellular matrix (ECM)-related genes through Prrx1 under oxidative stress. The impact of PF on BBB integrity under oxidative stress was investigated using a dual-layer BBB model, and we explored the protective effect of PF on tight junction proteins and ECM-related genes in mice after TBI. The study found that high-grade glioma and TBI share ECM instability as an important molecular pathological mechanism. PF stabilizes the ECM and protects the BBB by directly binding to Prrx1 or indirectly regulating Prrx1 through miRNAs. In addition, PF reduces intracellular calcium ions and ROS levels under oxidative stress, thereby preserving BBB integrity. In a TBI mouse model, PF protected BBB integrity through up-regulated tight junction proteins and stabilized the expression of ECM-related genes. Our study reveals the shared molecular pathogenesis between TBI and glioblastoma and demonstrate the potential of PF as a protective agent of BBB. This provides new targets and approaches for the development of novel neurotrauma therapeutic drugs.

Metabolic Roles of HIF1, c-Myc, and p53 in Glioma Cells

The metabolic reprogramming that promotes tumorigenesis in glioblastoma is induced by dynamic alterations in the hypoxic tumor microenvironment, as well as in transcriptional and signaling networks, which result in changes in global genetic expression. The signaling pathways PI3K/AKT/mTOR and RAS/RAF/MEK/ERK stimulate cell metabolism, either directly or indirectly, by modulating the transcriptional factors p53, HIF1, and c-Myc. The overexpression of HIF1 and c-Myc, master regulators of cellular metabolism, is a key contributor to the synthesis of bioenergetic molecules that mediate glioma cell transformation, proliferation, survival, migration, and invasion by modifying the transcription levels of key gene groups involved in metabolism. Meanwhile, the tumor-suppressing protein p53, which negatively regulates HIF1 and c-Myc, is often lost in glioblastoma. Alterations in this triad of transcriptional factors induce a metabolic shift in glioma cells that allows them to adapt and survive changes such as mutations, hypoxia, acidosis, the presence of reactive oxygen species, and nutrient deprivation, by modulating the activity and expression of signaling molecules, enzymes, metabolites, transporters, and regulators involved in glycolysis and glutamine metabolism, the pentose phosphate cycle, the tricarboxylic acid cycle, and oxidative phosphorylation, as well as the synthesis and degradation of fatty acids and nucleic acids. This review summarizes our current knowledge on the role of HIF1, c-Myc, and p53 in the genic regulatory network for metabolism in glioma cells, as well as potential therapeutic inhibitors of these factors.

Differential Susceptibility to Propofol and Ketamine in Primary Cultures of Young and Senesced Astrocytes

The adverse effects of general anesthesia on the long-term cognition of young children and senior adults have become of concern in recent years. Previously, mechanistic and pathogenic investigations focused on neurons, and little is known about the effect of commonly used intravenous anesthetics such as propofol and ketamine on astrocytes. Recently, astrocyte dysfunction has been implicated in a wide range of age-related brain diseases. In this study, we examined the survival and viability of both young and senescent astrocytes in culture after adding propofol and ketamine to the media at varying strengths. Oxidative stimulus was applied to commercially available fetal cell lines of human astrocytes in vitro to induce morphological changes in cellular senescence. Our results indicate that propofol reduces the survival of young astrocytes as compared to controls, as well as to ketamine. These effects were seen in comparisons of total cell count and at both high and low dose concentrations. High doses of propofol also significantly reduced cell viability compared to those exposed to baseline controls and ketamine. Senescent astrocytes, on the other hand, demonstrated cell count reductions as compared to baseline controls and ketamine when exposed to either DMSO or propofol. The data show differential susceptibility of young astrocytes to propofol than to ketamine. The observed cell count reduction may be related to the adverse effects of propofol on mitochondrial function and free radical production, as described in previous studies. We speculate that ketamine may have a more favorable safety profile in infants and young children.

Propofol Inhibits Glioma Stem Cell Growth and Migration and Their Interaction with Microglia via BDNF-AS and Extracellular Vesicles

Glioblastoma (GBM) is the most common and aggressive primary brain tumor. GBM contains a small subpopulation of glioma stem cells (GSCs) that are implicated in treatment resistance, tumor infiltration, and recurrence, and are thereby considered important therapeutic targets. Recent clinical studies have suggested that the choice of general anesthetic (GA), particularly propofol, during tumor resection, affects subsequent tumor response to treatments and patient prognosis. In this study, we investigated the molecular mechanisms underlying propofol's anti-tumor effects on GSCs and their interaction with microglia cells. Propofol exerted a dose-dependent inhibitory effect on the self-renewal, expression of mesenchymal markers, and migration of GSCs and sensitized them to both temozolomide (TMZ) and radiation. At higher concentrations, propofol induced a large degree of cell death, as demonstrated using microfluid chip technology. Propofol increased the expression of the lncRNA BDNF-AS, which acts as a tumor suppressor in GBM, and silencing of this lncRNA partially abrogated propofol's effects. Propofol also inhibited the pro-tumorigenic GSC-microglia crosstalk via extracellular vesicles (EVs) and delivery of BDNF-AS. In conclusion, propofol exerted anti-tumor effects on GSCs, sensitized these cells to radiation and TMZ, and inhibited their pro-tumorigenic interactions with microglia via transfer of BDNF-AS by EVs.

Borax regulates iron chaperone- and autophagy-mediated ferroptosis pathway in glioblastoma cells

Glioblastoma (GBM) is classified as a stage-IV glioma. Unfortunately, there are currently no curative treatments for GBM. Poly(rC)-binding protein 1 (PCBP1) is a cytosolic iron chaperone with diverse functions. PCBP1 is also known to regulate autophagy, but the role of PCBP1 in ferroptosis, iron-dependent cell death pathway, remains unrevealed in GBM cells. Here, we investigated the effects of borax, a boron compound, on the ferroptosis signaling pathway mediated by PCBP1 and autophagy. The study analyzed cell viability, proliferation, and cell cycle on U87-MG and HMC3 cells to investigate the effects of borax. After determining the cytotoxic concentrations of borax, morphological analyzes and measurement of PCBP1, Beclin1, malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase 4 (GPx4) and acyl-CoA synthetase long chain family member 4 (ACSL4) levels were performed. Finally, expression levels of PCBP1, Beclin1, GPx4 and ACSL4, and caspase-3/7 activity were determined. We found that borax reduced U87-MG cell viability in a concentration- and time-dependent manner. Additionally, borax altered cell proliferation and remarkably reduced S phase in the U87-MG cells and exhibited selectivity by having an opposite effect on normal cells (HMC3). According to DAPI staining, borax caused nuclear deficits in U87-MG cells. The result showed that borax in U87-MG cells induced reduction of the PCBP1, GSH, and GPx4 and enhancement of Beclin1, MDA, and ACSL4. Furthermore, borax triggered apoptosis by activating caspase 3/7 in U87-MG cells. Our study indicated that the borax has potential as an anticancer treatment for GBM via regulating PCBP1/Beclin1/GPx4/ACSL4 signaling pathways.

Antrodia camphorata and coenzyme Q0 , a novel quinone derivative of Antrodia camphorata, impede HIF-1α and epithelial-mesenchymal transition/metastasis in human glioblastoma cells

Antrodia camphorata (AC) and Coenzyme Q₀ (CoQ₀ ), a novel quinone derivative of AC, exhibits antitumor activities. The present study evaluated EMT/metastasis inhibition and autophagy induction aspects of AC and CoQ₀ in human glioblastoma (GBM8401) cells. Our findings revealed that AC treatment (0-150 μg/mL) hindered tumor cell proliferation and migration/invasion in GBM8401 cells. Notably, AC treatment inhibited HIF-1α and EMT by upregulating epithelial marker protein E-cadherin while downregulating mesenchymal proteins Twist, Slug, Snail, and β-catenin. There was an appearance of the autophagy markers LC3-II and p62/SQSTM1, while ATG4B was downregulated by AC treatment. We also found that CoQ₀ (0-10 μM) could inhibit migration and invasion in GBM8401 cells. In particular, E-cadherin was elevated and N-cadherin, Vimentin, Twist, Slug, and Snail, were reduced upon CoQ₀ treatment. In addition, MMP-2/-9 expression and Wnt/β-catenin pathways were downregulated. Furthermore, autophagy inhibitors 3-MA or CQ reversed the CoQ₀ -elicited suppression of migration/invasion and metastasis-related proteins (Vimentin, Snail, and β-catenin). Results suggested autophagy-mediated antiEMT and antimetastasis upon CoQ₀ treatment. CoQ₀ inhibited HIF-1α and metastasis in GBM8401 cells under normoxia and hypoxia. HIF-1α knockdown using siRNA accelerated CoQ₀ -inhibited migration. Finally, CoQ₀ exhibited a prolonged survival rate in GBM8401-xenografted mice. Treatment with Antrodia camphorata/CoQ₀ inhibited HIF-1α and EMT/metastasis in glioblastoma.

Effect of anesthesia on the outcome of high-grade glioma patients undergoing supratentorial resection: study protocol for a pragmatic randomized controlled trial

BACKGROUND

High-grade glioma (HGG) is the most malignant brain tumor with poor outcomes. Whether anesthetic methods have an impact on the outcome of these patients is still unknown. Retrospective study has found no difference between intravenous and inhalation anesthesia on the overall survival (OS) of the HGG patients, however, intravenous anesthesia with propofol might be beneficial in a subgroup of patients with a Karnofsky Performance Status (KPS) Scale less than 80. Further prospective studies are needed to evaluate the results.

METHODS

This is a single-centered, randomized controlled, parallel-group trial. Three hundred forty-four patients with primary HGG for tumor resection will be randomly assigned to receive either intravenous anesthesia with propofol or inhalation anesthesia with sevoflurane. The primary outcome is the OS of the patients within 18 months. Secondary outcomes include progression-free survival (PFS), the numerical rating scale (NRS) of pain intensity and sleep quality, the postoperative encephaloedema volume, complications, and the length of hospital stay of the patients.

DISCUSSION

This is a randomized controlled trial to compare the effect of intravenous and inhalation anesthesia maintenance on the outcome of supratentorial HGG patients. The results will contribute to optimizing the anesthesia methods in these patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02756312. Registered on 29 April 2016 and last updated on 9 Sep 2020.

Propofol enhances the sensitivity of glioblastoma cells to temozolomide by inhibiting macrophage activation in tumor microenvironment to down-regulate HIF-1α expression

Temozolomide (TMZ) is the first-line drug for the clinical treatment of glioblastoma (GBM), but drug resistance limits its treatment benefits. This study was intended to investigate whether propofol could restrict the resistance of GBM cells to TMZ and uncover the underlying mechanisms. Human GBM cell line U251 and TMZ-resistant U251/TMZ cell line were transplanted into mice to construct GBM and TMZ-resistant GBM xenograft tumors. Tumor growth in mice was monitored, and the tumor tissues were collected for biochemical analysis. THP-1 cell differentiated into M0 subtype macrophage using phorbol 12-myristate 13-acetate (PMA). The culture medium of M0 macrophage was collected for treating U251 cells with the presence or absence of propofol or propofol + DMOG (HIF-1α activator). Results showed that propofol significantly enhanced the inhibitory effect of TMZ on tumor growth, macrophage infiltration and inflammation in TMZ-resistant GBM xenograft tumors in vivo. Compared with GBM xenograft tumors, higher expression of HIF-1α, O6-methylguanine-DNA methyltransferase (MGMT), p-p65 and cyclooxygenase 2 (Cox2) was observed in TMZ-resistant GBM xenograft tumors, but propofol co-treatment markedly reduced the expression of these proteins. In in vitro experiments, culture medium from M0 macrophage promoted U251 cell survival, inflammation and expression of HIF-1α, MGMT, p65 and Cox2, whereas inhibited cell apoptosis. However, propofol suppressed the PMA-induced THP-1 M0 macrophage activation, and propofol-treated culture medium from M0 macrophage blocked all the effects of M0 medium on U251 cells. Additionally, DMOG reversed the effect of propofol-treated M0 medium on U251 cells. In conclusion, Propofol restricted TMZ resistance via inhibiting macrophage activation and down-regulating HIF-1α expression in GBM.

The Effects of Anesthetics on Glioma Progression: A Narrative Review

There are many established factors that influence glioma progression, including patient age, grade of tumor, genetic mutations, extent of surgical resection, and chemoradiotherapy. Although the exposure time to anesthetics during glioma resection surgery is relatively brief, the hemodynamic changes involved and medications used, as well as the stress response throughout the perioperative period, may also influence postoperative outcomes in glioma patients. There are numerous studies that have demonstrated that choice of anesthesia influences non-brain cancer outcomes; of particular interest are those describing that the use of total intravenous anesthesia may yield superior outcomes compared with volatile agents in in vitro and human studies. Much remains to be discovered on the topic of anesthesia's effect on glioma progression.

Propofol-based total intravenous anesthesia is associated with better survival than desflurane anesthesia in glioblastoma surgery

Background

Previous research has shown that anesthetic techniques can influence patient outcomes following cancer surgery. However, the effects of anesthesia in patients undergoing glioblastoma surgery are still not known. We studied the relationship between the type of anesthesia and patient outcomes following elective glioblastoma surgery.

Methods

This was a retrospective cohort study of patients who underwent elective glioblastoma surgery between January 2008 and December 2018. Patients were grouped according to the anesthesia they received, desflurane or propofol. A Kaplan-Meier analysis was conducted, and survival curves were presented from the date of surgery to death. Univariable and multivariable Cox regression models were used to compare hazard ratios for death after propensity matching.

Results

A total of 50 patients (45 deaths, 90.0%) under desflurane anesthesia and 53 patients (38 deaths, 72.0%) under propofol anesthesia were included. Thirty-eight patients remained in each group after propensity matching. Propofol anesthesia was associated with improved survival (hazard ratio, 0.51; 95% confidence interval, 0.30–0.85; P = 0.011) in a matched analysis. Furthermore, patients under propofol anesthesia exhibited less postoperative recurrence than those under desflurane anesthesia (hazard ratio, 0.60; 95% confidence interval, 0.37–0.98; P = 0.040) in a matched analysis.

Conclusions

In this limited sample size, we observed that propofol anesthesia was associated with improved survival and less postoperative recurrence in glioblastoma surgery than desflurane anesthesia. Further investigations are needed to examine the influence of propofol anesthesia on patient outcomes following glioblastoma surgery.

Oxidative stress under general intravenous and inhalation anaesthesia

Oxidative stress occurs when reactive oxygen species (ROS) production overwhelms cell protection by antioxidants. This review is focused on general anaesthesia-induced oxidative stress because it increases the rate of complications and delays recovery after surgery. It is important to know what effects of anaesthetics to expect in terms of oxidative stress, particularly in surgical procedures with high ROS production, because their either additive or antagonistic effect may be pivotal for the outcome of surgery. In vitro and animal studies on this topic are numerous but show large variability. There are not many human studies and what we know has been learned from different surgical procedures measuring different endpoints in blood samples taken mostly before and after surgery. In these studies most intravenous anaesthetics have antioxidative properties, while volatile anaesthetics temporarily increase oxidative stress in longer surgical procedures.

Anesthesia and brain tumor surgery: technical considerations based on current research evidence

PURPOSE OF REVIEW

Anesthetics may influence cancer recurrence and metastasis following surgery by modulating the neuroendocrine stress response or by directly affecting cancer cell biology. This review summarizes the current evidence on whether commonly used anesthetics potentially affect postoperative outcomes following solid organ cancer surgery with particular focus on neurological malignancies.

RECENT FINDINGS

Despite significant improvement in diagnostic and therapeutic technology over the past decades, mortality rates after cancer surgery (including brain tumor resection) remains high. With regards to brain tumors, interaction between microglia/macrophages and tumor cells by multiple biological factors play an important role in tumor progression and metastasis. Preclinical studies have demonstrated an association between anesthetics and brain tumor cell biology, and a potential effect on tumor progression and metastasis has been revealed. However, in the clinical setting, the current evidence is inadequate to draw firm conclusions on the optimal anesthetic technique for brain tumor surgery.

SUMMARY

Further work at both the basic science and clinical level is urgently needed to evaluate the association between perioperative factors, including anesthetics/technique, and postoperative brain tumor outcomes.

Impact of Anesthetics, Analgesics, and Perioperative Blood Transfusion in Pediatric Cancer Patients: A Comprehensive Review of the Literature

Cancer is the leading cause of death by disease in developed countries. Children and adolescents with cancer need surgical interventions (ie, biopsy or major surgery) to diagnose, treat, or palliate their malignancies. Surgery is a period of high vulnerability because it stimulates the release of inflammatory mediators, catecholamines, and angiogenesis activators, which coincides with a period of immunosuppression. Thus, during and after surgery, dormant tumors or micrometastasis (ie, minimal residual disease) can grow and become clinically relevant metastasis. Anesthetics (ie, volatile agents, dexmedetomidine, and ketamine) and analgesics (ie, opioids) may also contribute to the growth of minimal residual disease or disease progression. For instance, volatile anesthetics have been implicated in immunosuppression and direct stimulation of cancer cell survival and proliferation. Contrarily, propofol has shown in vitro anticancer effects. In addition, perioperative blood transfusions are not uncommon in children undergoing cancer surgery. In adults, an association between perioperative blood transfusions and cancer progression has been described for some malignancies. Transfusion-related immunomodulation is one of the mechanisms by which blood transfusions can promote cancer progression. Other mechanisms include inflammation and the infusion of growth factors. In the present review, we discuss different aspects of tumorigenesis, metastasis, angiogenesis, the immune system, and the current studies about the impact of anesthetics, analgesics, and perioperative blood transfusions on pediatric cancer progression.

Propofol directly induces caspase-1-dependent macrophage pyroptosis through the NLRP3-ASC inflammasome

Propofol infusion syndrome (PRIS) is an uncommon life-threatening complication observed most often in patients receiving high-dose propofol. High-dose propofol treatment with a prolonged duration can damage the immune system. However, the associated molecular mechanisms remain unclear. An increasing number of clinical and experimental observations have demonstrated that tissue-resident macrophages play a critical role in immune regulation during anaesthesia and procedural sedation. Since the inflammatory response is essential for mediating propofol-induced cell death and proinflammatory reactions, we hypothesised that propofol overdose induces macrophage pyroptosis through inflammasomes. Using primary cultured bone marrow-derived macrophages, murine macrophage cell lines (RAW264.7, RAW-asc and J774) and a mouse model, we investigated the role of NLRP3 inflammasome activation and secondary pyroptosis in propofol-induced cell death. We found that high-dose propofol strongly cleaved caspase-1 but not caspase-11 and biosynthesis of downstream interleukin (IL)-1β and IL-18. Inhibition of caspase-1 activity blocks IL-1β production. Moreover, NLRP3 deletion moderately suppressed cleaved caspase-1 as well as the proportion of pyroptosis, while levels of AIM2 were increased, triggering a compensatory pathway to pyroptosis in NLRP3^-/- macrophages. Here, we show that propofol-induced mitochondrial reactive oxygen species (ROS) can trigger NLRP3 inflammasome activation. Furthermore, apoptosis-associated speck-like protein (ASC) was found to mediate NLRP3 and AIM2 signalling and contribute to propofol-induced macrophage pyroptosis. In addition, our work shows that propofol-induced apoptotic initiator caspase (caspase-9) subsequently cleaved effector caspases (caspase-3 and 7), indicating that both apoptotic and pyroptotic cellular death pathways are activated after propofol exposure. Our studies suggest, for the first time, that propofol-induced pyroptosis might be restricted to macrophage through an NLRP3/ASC/caspase-1 pathway, which provides potential targets for limiting adverse reactions during propofol application. These findings demonstrate that propofol overdose can trigger cell death through caspase-1 activation and offer new insights into the use of anaesthetic drugs.

Cadmium induces apoptotic program imbalance and cell cycle inhibitor expression in cultured human astrocytes

Cadmium is a highly neurotoxic heavy metal impairing neurogenesis and induces neurodegenerative disorders. Toxic concentrations of cadmium induce astrocytic apoptosis by depleting intracellular glutathione levels, elevating intracellular calcium levels, altering mitochondria membrane potentials, and activating JNK and PI3K/Akt signaling pathways. Cadmium suppresses cell proliferation in kidney epithelial cells, lung fibroblasts, and primary myelocytes; however, cadmium's effects on proteins regulating oxidative stress, apoptosis, and cell proliferation in astrocytes are less known. The present study hypothesized that cadmium alters levels of antioxidant enzymes, apoptotic regulator proteins, and cell cycle inhibitor proteins, resulting in apoptosis and cell cycle arrest. Concentrations ≥20 μM cadmium induced apoptosis and led to intracellular changes including DNA fragmentation, reduced mRNA expression of antioxidant enzymes (i.e., catalase and glutathione S transferase-A4), downregulation of B-cell lymphoma 2 (Bcl-2), and upregulation of Bcl-2-associated X protein (Bax). Moreover, cadmium suppressed astrocytic proliferation by inducing S and G2/M phase cell cycle arrest and promoting p53, p21, and p27 expression. In conclusion, this study provides mechanistic insight into cadmium-induced cytotoxicity of astrocytes and highlights potential targets for prevention of cadmium-induced apoptosis and cell cycle arrest.