DNA Damage-Induced Apoptosis Suppressor Triggers Progression and Stemness of Glioma by Enhancing Lymphoid Enhancer-Binding Factor 1 Expression.

Background: DNA damage-induced apoptosis suppressor (DDIAS) has recently been discovered to induce cancer progression, but its functions and mechanisms in glioma have not been well studied. Methods: DDIAS expression in glioma tissues was analyzed by the Gene Expression Profiling Interactive Analysis server (GEPIA) and the Gene Expression database of Normal and Tumor tissue 2 (GENT2) databases. The role of DDIAS in glioma progression was studied by short hairpin RNA (shRNA) targeting DDIAS. The effects of DDIAS on glioma cell viability, cell proliferation, invasion, migration, and tumor sphere formation were determined by cell counting kit-8 (CCK-8), EdU, Transwell, tumor spheroid formation, extreme limiting dilution analysis assays in vitro and xenograft model construction in vivo. In addition, RNA sequencing and further functional experiments were used to analyze the DDIAS regulatory mechanism in glioma. Results: We found that DDIAS was highly expressed in glioma and that upregulated DDIAS indicated poor prognosis. Functionally, DDIAS knockdown inhibited glioma cell viability, cell proliferation, invasion and migration in vitro and tumor growth in vivo. In addition, lymphoid enhancer-binding factor 1 (LEF1) was identified as the downstream effector of DDIAS by RNA sequencing. DDIAS downregulation inhibited LEF1 mRNA and protein expression. The expression of DDIAS and LEF1 was positively correlated, and LEF1 overexpression rescued the inhibitory phenotype induced by DDIAS downregulation. We further showed that DDIAS downregulation inhibited cyclin A1, vimentin and the stemness-related factor CD133 and decreased the sphere formation capability, but these features were rescued by upregulation of LEF1. Conclusion: Taken together, these findings suggest that DDIAS promotes glioma progression and stemness by inducing LEF1 expression, proving that DDIAS may be a potential target for the treatment of glioma.

Gamabufotalin induces a negative feedback loop connecting ATP1A3 expression and the AQP4 pathway to promote temozolomide sensitivity in glioblastoma cells by targeting the amino acid Thr794.

OBJECTIVES: Temozolomide (TMZ) is one of the most commonly used clinical drugs for glioblastoma (GBM) treatment, but its drug sensitivity needs to be improved. Gamabufotalin (CS-6), the primary component of the traditional Chinese medicine "ChanSu," was shown to have strong anti-cancer activity. However, more efforts should be directed towards reducing its toxicity or effective treatment doses. METHODS: Target fishing experiment, Western blotting, PCR, confocal immunofluorescence and molecular cloning techniques were performed to search for possible downstream signalling pathways. In addition, GBM xenografts were used to further determine the potential molecular mechanisms of the synergistic effects of CS-6 and TMZ in vivo. RESULTS: Mechanistic research revealed a negative feedback loop between ATP1A3 and AQP4 through which CS-6 inhibited GBM growth and mediated the synergistic treatment effect of CS-6 and TMZ. In addition, by mutating potential amino acid residues of ATP1A3, which were predicted by modelling and docking to interact with CS-6, we demonstrated that abrogating hydrogen bonding of the amino acid Thr794 interferes with the activation of ATP1A3 by CS-6 and that the Thr794Ala mutation directly affects the synergistic treatment efficacy of CS-6 and TMZ. CONCLUSIONS: As the main potential target of CS-6, ATP1A3 activation critically depends on the hydrogen bonding of Thr794 with CS-6. The combination of CS-6 and TMZ could significantly reduce the therapeutic doses and promote the anti-cancer efficacy of CS-6/TMZ monotherapy.

A research update on the anticancer effects of bufalin and its derivatives.

Bufalin (BF) is a cardiotonic steroid that has recently been found to have substantial anticancer activity; however, more efforts should be directed toward clarifying the detailed molecular mechanisms underlying this activity. BF could exert its anticancer effect by inducing apoptosis in various human cancer cells and thus triggering autophagic cancer cell death. The anti-inflammatory activities of BF are potentially important for its anticancer functions. Notably, some promising synthetic BF derivatives, including poly (ethylene glycol)-based polymeric prodrug of BF and BF211, have shown potent anticancer activity. Additionally, clinical trials regarding the use of BF-related agents in patients have supported the positive effect of BF as an anticancer treatment. Currently, large-scale randomized, double-blind, placebo or positive drug parallel controlled studies are required to confirm the anticancer potential of BF in various cancer types in the clinical setting. The present review will evaluate the potential mechanisms mediated by BF in intracellular signaling events in cancer cells and various promising BF derivatives that may have greater anticancer activity, thereby clarifying BF-mediated anticancer effects. The experimental and clinical results reviewed strongly emphasize the importance of this topic in future investigations.

Isoalantolactone inhibits IKKß kinase activity to interrupt the NF-κB/COX-2-mediated signaling cascade and induces apoptosis regulated by the mitochondrial translocation of cofilin in glioblastoma.

Isoalantolactone (IATL), a sesquiterpene lactone compound, possesses many pharmacological and biological activities, but its role in glioblastoma (GBM) treatment is still unknown. The aim of the current study was to investigate the antiglioma effects of IATL and to explore the underlying molecular mechanisms. In the current study, the biological functions of IATL were examined by MTT, cell migration, colony formation, and cell apoptosis assays. Confocal immunofluorescence techniques, chromatin immunoprecipitation, and pull-down assays were used to explore the precise underlying molecular mechanisms. To examine IATL activity and the molecular mechanisms by which it inhibits glioma growth in vivo, we used a xenograft tumor mouse model. Furthermore, Western blotting was used to confirm the changes in protein expression after IATL treatment. According to the results, IATL inhibited IKKß phosphorylation, thus inhibiting both the binding of NF-κB to the cyclooxygenase 2 (COX-2) promoter and the recruitment of p300 and eventually inhibiting COX-2 expression. In addition, IATL induced glioma cell apoptosis by promoting the conversion of F-actin to G-actin, which in turn activates the cytochrome c (Cyt c) and caspase-dependent apoptotic pathways. In the animal experiments, IATL reduced the size and weight of glioma tumors in xenograft mice and inhibited the expression of COX-2 and phosphorylated NF-κB p65 in the transplanted tumors. In conclusion, the current study indicated that IATL inhibited the expression of COX-2 through the NF-κB signaling pathway and induced the apoptosis of glioma cells by increasing actin transformation. These results suggested that IATL could be greatly effective in GBM treatment.

Bazedoxifene protects cerebral autoregulation after traumatic brain injury and attenuates impairments in blood-brain barrier damage: involvement of anti-inflammatory pathways by blocking MAPK signaling.

OBJECTIVE: Traumatic brain injury (TBI) is a significant cause of death and long-term deficits in motor and cognitive functions for which there are currently no effective chemotherapeutic drugs. Bazedoxifene (BZA) is a third-generation selective estrogen receptor modulator (SERM) and has been investigated as a treatment for postmenopausal osteoporosis. It is generally safe and well tolerated, with favorable endometrial and breast safety profiles. Recent findings have shown that SERMs may have therapeutic benefits; however, the role of BZA in the treatment of TBI and its molecular and cellular mechanisms remain poorly understood. The aim of the present study was to examine the neuroprotective effects of BZA on early TBI in rats and to explore the underlying mechanisms of these effects. MATERIALS AND METHODS: TBI was induced using a modified weight-drop method. Neurological deficits were evaluated according to the neurological severity score (NSS). Morris water maze and open-field behavioral tests were used to test cognitive functions. Brain edema was measured by brain water content, and impairments in the blood-brain barrier (BBB) were evaluated by expression analysis of tight junction-associated proteins, such as occludin and zonula occludens-1 (ZO-1). Neuronal injury was assessed by hematoxylin and eosin (H&E) staining. LC-MS/MS analysis was performed to determine the ability of BZA to cross the BBB. RESULTS: Our results indicated that BZA attenuated the impaired cognitive functions and the increased BBB permeability of rats subjected to TBI through activation of inflammatory cascades. In vivo experiments further revealed that BZA provided this neuroprotection by suppressing TBI-induced activation of the MAPK/NF-κB signaling pathway. Thus, mechanically, the anti-inflammatory effects of BZA in TBI may be partially mediated by blocking the MAPK signaling pathway. CONCLUSIONS: These findings suggest that BZA might attenuate neurological deficits and BBB damage to protect against TBI by blocking the MAPK/NF-κB signaling pathway.

The sodium pump α1 subunit regulates bufalin sensitivity of human glioblastoma cells through the p53 signaling pathway.

Bufalin is the primary component of the traditional Chinese medicine "Chan Su," which has been widely used for cancer treatment at oncology clinics in certain countries. Evidence suggests that this compound possesses potent antitumor activities, although the exact molecular mechanism(s) require further elucidation. Therefore, this study aimed to further clarify the in vitro and in vivo antiglioma effects of bufalin and the molecular mechanism underlying the regulation of drug sensitivity. The anticancer effects of bufalin were determined by colony formation assays, apoptosis assays, and cellular redox state tests of glioma cells. Confocal microscopy was performed to determine the expression changes of the DNA damage biomarker γ-H2AX and the nuclear translocation of p53 in glioma cells. Western blotting and RT-PCR were used to detect the protein and gene expression levels, respectively. Here, we report that bufalin induced glioblastoma cell apoptosis and oxidative stress and triggered DNA damage. The critical roles of the sodium pump α1 subunit (ATP1A1) in mediating the XPO1-targeted anticancer effect of bufalin in human glioma were further confirmed. Mechanistic studies confirmed the important roles of Src and p53 signaling in mediating bufalin-induced apoptosis. Importantly, bufalin also inhibited the growth of glioma xenografts. In conclusion, our study indicated that therapies targeting the ATP1A1 and p53 signaling-mediated mitochondrial apoptotic pathways regulated by bufalin might be potential treatments for human glioma, and these findings will provide molecular bases for developing bufalin into a drug candidate for the treatment of malignant glioma.

Bufalin inhibits glioblastoma growth by promoting proteasomal degradation of the Na+/K+-ATPase α1 subunit.

Chansu is a traditional Chinese medicine that is generally recognized as a specific inhibitor of Na+/K+-ATPase. Bufalin, an active component of Chansu, is an endogenous steroid hormone with great potential as a cancer treatment. However, the mechanism by which it exerts its antitumor activity requires further research. Currently, the α1 subunit of Na+/K+-ATPase (ATP1A1) is known to exert important roles in tumorigenesis, and the precise mechanisms underlying the effect of Bufalin on the Na+/K+-ATPase α1 subunit was therefore investigated in this study to determine its role in glioblastoma treatments. The effect of ATP1A1 on the sensitivity of glioblastoma cells to Bufalin was investigated using MTT assays, RT-PCR and siRNA. Western blot was also used to explore the important roles of the ubiquitin-proteasome pathway in the Bufalin-mediated inhibition of ATP1A1. Xenografted mice were used to examine the anti-tumor activity of Bufalin in vivo. LC-MS/MS analysis was performed to determine the ability of Bufalin to traverse the blood-brain barrier (BBB). The results indicated that Bufalin inhibited the expression of ATP1A1 in glioblastoma by promoting the activation of proteasomes and the subsequent protein degradation of ATP1A1, while Bufalin had no effect on ATP1A1 protein synthesis. Bufalin also inhibited the expression of ATP1A1 in xenografted mice and significantly suppressed tumor growth. These data should contribute to future basic and clinical investigations of Bufalin. In conclusion, Bufalin significantly inhibited the expression of ATP1A1 in glioblastoma cells by activating the ubiquitin-proteasome signaling pathway. Bufalin may therefore have the potential to be an effective anti-glioma drug for human glioblastoma in the future.

Alantolactone plays neuroprotective roles in traumatic brain injury in rats via anti-inflammatory, anti-oxidative and anti-apoptosis pathways.

Traumatic brain injury (TBI) is a common disease associated with a high rate of morbidity and mortality. Secondary brain injury following TBI triggers pathological, physiological, and biological reactions that lead to neurological dysfunctions. Alantolactone (ATL) is a well-known Chinese medicine that possesses strong anti-inflammatory properties, but its role in TBI remains poorly understood. The objective of this study was to evaluate the protective effect of ATL in a rat model of controlled cortical impact (CCI). We observed the neurological scores, brain water content, oxidative stress, neuroinflammation and apoptosis by performing an enzyme-linked immunosorbent assay, western blotting, quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), immunohistochemical (IHC) staining and other methods after CCI. The neurological scores, brain water content, levels of oxidative stress and inflammatory cytokines, and apoptosis index were markedly decreased following the ATL treatment in rats after TBI. Moreover, the antioxidant and anti-inflammatory effects of ATL in TBI may be partially mediated by inhibition of the NF-κB pathway and suppression of Cyclooxygenase 2 (COX-2). In addition, ATL attenuated TBI-induced neuronal apoptosis by suppressing the cytochrome c/caspase-dependent apoptotic pathway. Thus, ATL could exert neuroprotection in rats in a TBI model. Importantly, ATL has great potential in the clinical treatment of TBI.

Marinobufagenin inhibits glioma growth through sodium pump α1 subunit and ERK signaling-mediated mitochondrial apoptotic pathway.

Malignant glioma is one of the most challenging central nervous system diseases to treat and has high rates of recurrence and mortality. Current therapies often fail to control tumor progression or improve patient survival. Marinobufagenin (MBG) is an endogenous mammalian cardiotonic steroid involved in sodium pump inhibition. Currently, various studies have indicated the potential of MBG in cancer treatments; however, the precise mechanisms are poorly understood. The functions of MBG were examined using colony formation, migration, cell cycle, and apoptosis assays in glioma cells. A mitochondrial membrane potential assay was performed to determine the mitochondrial transmembrane potential change, and cytochrome c release from mitochondria was assayed by fluorescence microscopy. An immunofluorescence assay was performed, and the nuclear translocation of NF-κB in glioma cells was confirmed by confocal microscopy. Western blotting and RT-qPCR were used to detect the protein and gene expression levels, respectively. In addition, transfection experiment of ATP1A1-siRNA was further carried out to confirm the role of sodium pump α1 subunit in the anticancer effect of MBG in human glioma. The apoptosis-promoting and anti-inflammatory effects of MBG were further investigated, and the sodium pump α1 subunit and the ERK signaling pathway were found to be involved in the anticancer effect of MBG. The in vivo anticancer efficacy of MBG was also tested in xenografts in nude mice. Thus, therapies targeting the ERK signaling-mediated mitochondrial apoptotic pathways regulated by MBG might represent potential treatments for human glioma, and this study could accelerate the finding of newer therapeutic approaches for malignant glioma treatment.

Update on the effect of exogenous hormone use on glioma risk in women: a meta-analysis of case-control and cohort studies.

Various studies have confirmed the important roles of endogenous hormones in the development of gliomas, while the roles of exogenous hormones remain controversial. Based on case-control studies and cohort studies, a meta-analysis was exerted to explore the effect of two exogenous hormones use (HRT: hormone replacement therapy; OC: oral contraceptives) on glioma risk. 16 eligible studies, including 11 case-control studies and 5 cohort studies, containing 8055027 women, were included in our study. All included studies have reported the relative risks (RRs) or odds ratios (ORs), and 95% confidence intervals (CIs). We use the fixed-effects model to calculate the estimated overall risk. In case-control studies, the risk of glioma was lower in women who had ever been treated with an exogenous hormone than in the control group (HRT: OR 0.91, 95% CI 0.84-0.99; OC: OR 0.99, 95% CI 0.91-1.07). In research of cohort studies, similar results have been obtained (HRT: RR 0.95, 95% CI 0.83-1.08; OC: RR 0.75, 95% CI 0.66-0.84). Our study further confirmed that the use of exogenous hormones has an important impact on the risk of glioma in women. However, more prospective studies are needed to further confirm this conclusion.

Anti-cancer effects of dopamine in human glioma: involvement of mitochondrial apoptotic and anti-inflammatory pathways.

Despite the emergence of innovative cancer treatment strategies, the global burden imposed by malignant glioma is expected to increase; thus, new approaches for treating the disease are urgently required. Dopamine, a monoamine catecholamine neurotransmitter, is currently regarded as an important endogenous regulator of tumor growth. Dopamine may play an important role in glioma treatment; however, the mechanism underlying the anti-tumor activity of dopamine remains poorly understood. Here, we explored the potential roles of dopamine in glioma and highlight the importance of endogenous regulators of tumor growth. We report that dopamine inhibited glioma cell proliferation. We investigated the biological functions of dopamine via migration, colony formation and apoptosis assays in glioma cells. We also evaluated cytochrome c release from the mitochondria and p50 and p65 subcellular localization by fluorescence microscopy. We performed western blotting and real-time quantitative polymerase chain reaction to detect apoptosis and inflammatory marker protein and gene expression levels, respectively. NF-κB p50/p65 nuclear localization was analyzed after U87MG and U251 cells were treated with dopamine. The in vivo anti-tumor efficacy of dopamine was also analyzed in xenograft mice. Taken together, our results indicated that dopamine induced apoptosis by activating the cytochrome c and caspase-dependent apoptotic pathway. Moreover, dopamine markedly down-regulated inflammation-related protein expression levels and p50/p65 NF-κB nuclear localization in tumor cells, thereby inhibiting increases in tumor weight and size in xenograft mice. Thus, therapies targeting the mitochondrial apoptotic and anti-inflammatory signaling pathways regulated by dopamine may represent promising treatments for human glioma.

Update on the therapeutic significance of estrogen receptor beta in malignant gliomas.

Malignant glioma is the most fatal of the astrocytic lineage tumors despite therapeutic advances. Men have a higher glioma incidence than women, indicating that estrogen level differences between men and women may influence glioma pathogenesis. However, the mechanism underlying the anticancer effects of estrogen has not been fully clarified and is complicated by the presence of several distinct estrogen receptor types and the identification of a growing number of estrogen receptor splice variants. Specifically, it is generally accepted that estrogen receptor alpha (ERα) functions as a tumor promoter, while estrogen receptor beta (ERß) functions as a tumor suppressor, and the role and therapeutic significance of ERß signaling in gliomas remains elusive. Thus, a deeper analysis of ERß could elucidate the role of estrogens in gender-related cancer incidence. ERß has been found to be involved in complex interactions with malignant gliomas. In addition, the prognostic value of ERß expression in glioma patients should not be ignored when considering translating experimental findings to clinical practice. More importantly, several potential drugs consisting of selective ERß agonists have exhibited anti-glioma activities and could further extend the therapeutic potential of ERß-selective agonists. Here, we review the literature to clarify the anti-glioma effect of ERß. To clarify ERß-mediated treatment effects in malignant gliomas, this review focuses on the potential mechanisms mediated by ERß in the intracellular signaling events in glioma cells, the prognostic value of ERß expression in glioma patients, and various ERß agonists that could be potential drugs with anti-glioma activities.

Solasonine inhibits glioma growth through anti-inflammatory pathways.

The global burden of malignant glioma is expected to increase and new therapy approaches are urgently required. Solasonine is a natural glycoalkaloid compound that has been used in cancer treatment for many years; however the precise mechanisms are poorly understood. Here we seek to explore the potential roles of solasonine in glioma that could add to the development of newer therapeutic approaches for the treatment of malignant glioma. Cell proliferation of glioma cells was determined by MTT assay, and the biological functions of solasonine were investigated by migration, colony formation, apoptosis assays and cell cycle analysis in glioma cells. Western blotting and RT-qPCR were used to detect the protein and gene expression levels respectively. The nuclear localization of NF-κB p50/p65 was analyzed after treatment with solasonine. The roles of MAPKs in the anticancer effect of solasonine were then examined. The in vivo anti-tumor efficacy of dopamine was also analyzed in xenografts nude mice. We report that solasonine could inhibit cell proliferation, migration and colony formation of glioma cells. Treatment of solasonine induced apoptosis via modulating cytochrome c and caspase signaling. Besides, solasonine decreased the expression of proinflammatory mediators and nuclear translocalization of NF-κB p50/p65. Mechanistic investigation further revealed that solasonine may target anti-inflammatory signaling pathway, and more specifically p-p38 and p-JNK MAPKs. All these indicated that solasonine could inhibit glioma growth via inhibiting inflammatory signaling pathway.

The potential roles of dopamine in malignant glioma.

Despite the numerous promising discoveries in contemporary cancer research and the emerging innovative cancer treatment strategies, the global burden of malignant glioma is expected to increase, partially due to its poor prognosis and human aging. Dopamine, a monoamine catecholamine neurotransmitter, is currently regarded as an important endogenous regulator of tumor growth. Dopamine may be an important treatment for brain tumors and could impact the pathogenesis of glioma by regulating tumor angiogenesis and vasculogenesis. Additionally, dopamine might exert an anti-glioma, cytotoxic effect by modulating apoptosis and autophagy. Dopamine and its receptors are also known to influence the immune system, as it is related to the pathogenesis of glioma. Dopamine may also increase the efficacy of anti-cancer drugs. Here, we review the potential roles of dopamine in malignant glioma and further identify the previously unknown function of dopamine as a potent regulator in the pathogenesis of glioma. Currently, the precise mechanisms regarding the protective effect of dopamine on glioma are poorly understood. However, our experimental results strongly emphasize the importance of this topic in future investigations.