Mps one binder 2 (MOB2) regulates the NDR kinase family, however, whether and how it is implicated in cancer remain unknown. Here we show that MOB2 functions as a tumor suppressor in glioblastoma ...(GBM). Analysis of MOB2 expression in glioma patient specimens and bioinformatic analyses of public datasets revealed that MOB2 was downregulated at both mRNA and protein levels in GBM. Ectopic MOB2 expression suppressed, while depletion of MOB2 enhanced, the malignant phenotypes of GBM cells, such as clonogenic growth, anoikis resistance, and formation of focal adhesions, migration, and invasion. Moreover, depletion of MOB2 increased, while overexpression of MOB2 decreased, GBM cell metastasis in a chick chorioallantoic membrane model. Overexpression of MOB2-mediated antitumor effects were further confirmed in mouse xenograft models. Mechanistically, MOB2 negatively regulated the FAK/Akt pathway involving integrin. Notably, MOB2 interacted with and promoted PKA signaling in a cAMP-dependent manner. Furthermore, the cAMP activator Forskolin increased, while the PKA inhibitor H89 decreased, MOB2 expression in GBM cells. Functionally, MOB2 contributed to the cAMP/PKA signaling-regulated inactivation of FAK/Akt pathway and inhibition of GBM cell migration and invasion. Collectively, these findings suggest a role of MOB2 as a tumor suppressor in GBM via regulation of FAK/Akt signaling. Additionally, we uncover MOB2 as a novel regulator in cAMP/PKA signaling. Given that small compounds targeting FAK and cAMP pathway have been tested in clinical trials, we suggest that interference with MOB2 expression and function may support a theoretical and therapeutic basis for applications of these compounds.
Background/Aims: Diseases caused by atherosclerosis are the leading causes of death in postmenopausal women, owing to the loss of estradiol. Hormone replacement therapy (HRT) provides short-term ...beneficial effects in the treatment of cardiovascular disease for postmenopausal women but may increase the risk of stroke and gynecological cancer. Therefore, a substitute for HRT is urgently in needed. Methods: In this study, we examined the effectiveness of alpha-lipoic acid (ALA), a natural potent antioxidant, in preventing the development and progression of atherosclerosis in the low density lipoprotein receptor deficient (Ldlr-/-) mouse model, using western blot analysis, immunohistochemistry, Oil-red-O, elastin staining and TUNEL assay. We also examined the protective effect of ALA in human aortic endothelial cells (HAECs) against H2O2-induced oxidative injury, using western blotting, immunofluorescence staining, and monocyte adhesion assay. Results: We showed that ALA treatment significantly reduced the atherosclerosis induced by ovariectomy and high fat diet in the Ldlr-/- mouse model and restored expression of estrogen receptors (ERα and ERβ), which reduced the progression of atherosclerosis. Moreover, ALA treatment attenuated monocyte adhesion, suppressed cellular apoptosis, and eliminated excessive generation of intracellular reactive oxygen species (ROS) by reducing the protein levels of ROS-generating enzymes Nox4 and p22phox, as well as inhibiting NF-κB activation in HAECs stimulated by H2O2. Conclusions: ALA could provide a potential treatment for atherosclerosis in postmenopausal patients.
Significant advance has been made towards understanding glioblastoma metabolism through global metabolomic profiling. However, hitherto little is known about the role by which altered metabolism ...plays in driving the aggressive glioma phenotype. We have previously identified hypotaurine as one of the top-ranked metabolites for differentiating low- and high-grade tumors, and that there is also a strong association between the levels of intratumoral hypotaurine and expression of its biosynthetic enzyme, cysteamine (2-aminoethanethiol) dioxygenase (ADO). Using transcription profiling, we further uncovered that the ADO/hypotaurine axis targets CCL20 secretion through activating the NF-κB pathway to drive the self-renewal and maintenance of glioma 'cancer stem cells' or glioma cancer stem-like cells. Conversely, abrogating the ADO/hypotaurine axis using CRISPR/Cas9-mediated gene editing limited glioblastoma cell proliferation and self-renewal in vitro and tumor growth in vivo in an orthotopical mouse model, indicating that this metabolic pathway is a potential key therapeutic target. Collectively, our results unveil a targetable metabolic pathway, which contributes to the growth and progression of aggressive high-grade gliomas, as well as a novel predictive marker for glioblastoma diagnosis and therapy.
The efficacy of osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor, has been evaluated in glioblastoma (GBM) through preclinical and clinical trials. However, ...the underlying mechanism of osimertinib-induced GBM cell death and the underlying resistance mechanism to osimertinib remains unclear. Here, we demonstrate that Osimertinib induces paraptosis in GBM cells, as evidenced by the formation of cytoplasmic vacuoles, accumulation of ubiquitinated proteins, and upregulation of endoplasmic reticulum (ER) stress markers like CHOP. Additionally, neither apoptosis nor autophagy was involved in the osimertinib-induced cell death. RNAseq analysis revealed ER stress was the most significantly downregulated pathway upon exposure to osimertinib. Consistently, pharmacologically targeting the PERK-eIF2α axis impaired osimertinib-induced paraptosis. Notably, we show that the expression of thyroid receptor-interacting protein 13 (TRIP13), an AAA+ATPase, alleviated osimertinib-triggered paraptosis, thus conferring resistance. Intriguingly, MK-2206, an AKT inhibitor, downregulated TRIP13 levels and synergized with Osimertinib to suppress TRIP13-induced high GBM cell growth in vitro and in vivo. Together, our findings reveal a novel mechanism of action associated with the anti-GBM effects of osimertinib involving ER stress-regulated paraptosis. Furthermore, we identify a TRIP13-driven resistance mechanism against Osimertinib in GBM and offer a combination strategy using MK-2206 to overcome such resistance.
Ferroptosis is a new kind of regulated cell death that is characterized by highly iron-dependent lipid peroxidation. Cancer cells differ in their sensitivity to ferroptosis. Here we showed that the ...Suppressor of fused homolog (SUFU), a critical component in Hedgehog signaling, regulates ferroptosis sensitivity of breast cancer cells. Ectopic SUFU expression suppressed, whereas depletion of SUFU enhanced the sensitivity of breast cancer cells to RSL3-triggered ferroptosis through deregulation of ACSL4. Moreover, SUFU depletion promoted the activation of Yes-associated protein (YAP), thereby increasing the expression of ACSL4. Mechanistically, SUFU is associated with LATS1. Deletion of a region comprising residues 174–385 in SUFU disrupted SUFU binding to LATS1, thus abrogating SUFU-mediated downregulation of the YAP-ACSL4 axis and sensitivity to ferroptosis. Noteworthy, we showed that vincristine downregulated SUFU, thus increasing breast cancer cell sensitivity to RSL3 in vitro and in vivo. Together, our findings uncover SUFU as a novel regulator in ferroptosis sensitivity.
Display omitted
•SUFU regulates the sensitivity of breast cancer cells to ferroptosis•SUFU associates with LATS1 to downregulate the YAP-ACSL4 axis•Vincristine targets the SUFU-YAP-ACSL4 axis
Cell biology; Functional aspects of cell biology; Cancer
Background/Aims: Diseases caused by atherosclerosis are the leading causes of death in postmenopausal women, owing to the loss of estradiol. Hormone replacement therapy (HRT) provides short-term ...beneficial effects in the treatment of cardiovascular disease for postmenopausal women but may increase the risk of stroke and gynecological cancer. Therefore, a substitute for HRT is urgently in needed. Methods: In this study, we examined the effectiveness of alpha-lipoic acid (ALA), a natural potent antioxidant, in preventing the development and progression of atherosclerosis in the low density lipoprotein receptor deficient (Ldlr-/-) mouse model, using western blot analysis, immunohistochemistry, Oil-red-O, elastin staining and TUNEL assay. We also examined the protective effect of ALA in human aortic endothelial cells (HAECs) against H2O2-induced oxidative injury, using western blotting, immunofluorescence staining, and monocyte adhesion assay. Results: We showed that ALA treatment significantly reduced the atherosclerosis induced by ovariectomy and high fat diet in the Ldlr-/- mouse model and restored expression of estrogen receptors (ERα and ERβ), which reduced the progression of atherosclerosis. Moreover, ALA treatment attenuated monocyte adhesion, suppressed cellular apoptosis, and eliminated excessive generation of intracellular reactive oxygen species (ROS) by reducing the protein levels of ROS-generating enzymes Nox4 and p22phox, as well as inhibiting NF-κB activation in HAECs stimulated by H2O2. Conclusions: ALA could provide a potential treatment for atherosclerosis in postmenopausal patients.
The epithelial-mesenchymal transition (EMT) is an important factor in lung cancer metastasis, and targeting EMT is a potential therapeutic strategy. Fucosyltransferase IV (FUT4) and its synthetic ...cancer sugar antigen Lewis Y (LeY) was abnormally elevated in many cancers. In this study, a traditional Chinese medicine ginsenoside Rg3 was used to investigate whether its inhibition to EMT and invasion of lung cancer is by the glycobiology mechanism. We found that Rg3 treatment (25, 50, 100 μg/ml) inhibited cell migration and invasion by wound-healing and transwell assays. Rg3 could significantly alter EMT marker proteins with increased E-cadherin, but decreased Snail, N-cadherin and Vimentin expression. Rg3 also down-regulated FUT4 gene and protein expression in lung cancer cells by qPCR, Western blot and immunofluorescence. After FUT4 down-regulated with shFUT4, EMT was obviously inhibited. Furthermore, the activation of EGFR through decreased LeY biosynthesis was inhibited, which blocked the downstream MAPK and NF-κB signal pathways. In addition, Rg3 reduced tumor volume and weight in xenograft mouse model, and significantly decreased tumor metastasis nodules in lung tissues by tail vein injection. In conclusion, Rg3 inhibits EMT and invasion of lung cancer by down-regulating FUT4 mediated EGFR inactivation and blocking MAPK and NF-κB signal pathways. Rg3 may be a potentially effective agent for the treatment of lung cancer.
Epidermal growth factor receptor (EGFR) amplification and EGFRvIII mutation drive glioblastoma (GBM) pathogenesis, but their regulation remains elusive. Here we characterized the EGFR/EGFRvIII ...“interactome” in GBM and identified thyroid receptor-interacting protein 13 (TRIP13), an AAA + ATPase, as an EGFR/EGFRvIII-associated protein independent of its ATPase activity. Functionally, TRIP13 augmented EGFR pathway activation and contributed to EGFR/EGFRvIII-driven GBM growth in GBM spheroids and orthotopic GBM xenograft models. Mechanistically, TRIP13 enhanced EGFR protein abundance in part by preventing Cbl-mediated ubiquitination and proteasomal degradation. Reciprocally, TRIP13 was phosphorylated at tyrosine(Y) 56 by EGFRvIII and EGF-activated EGFR. Abrogating TRIP13 Y56 phosphorylation dramatically attenuated TRIP13 expression-enhanced EGFR signaling and GBM cell growth. Clinically, TRIP13 expression was upregulated in GBM specimens and associated with poor patient outcome. In GBM, TRIP13 localized to cell membrane and cytoplasma and exhibited oncogenic effects in vitro and in vivo, depending on EGFR signaling but not the TRIP13 ATPase activity. Collectively, our findings uncover that TRIP13 and EGFR form a feedforward loop to potentiate EGFR signaling in GBM growth and identify a previously unrecognized ATPase activity-independent mode of action of TRIP13 in GBM biology.
∙TRIP13 associates with EGFR and EGFRvIII∙TRIP13 enhances EGFR stability, activation and downstream signaling∙TRIP13 contributes to EGFR/EGFRvIII-driven GBM growth∙EGFRvIII and EGF-activated EGFR phosphorylate TRIP13∙TRIP13 is up-regulated in GBM tissues and is associated with poor prognosis
Ceramide synthases (CerSs) catalyze the formation of ceramides from sphingoid bases and acyl-CoA substrates. Increasing evidence suggests that cancer cells generally exhibit altered sphingolipid ...metabolism in the tumorigenesis of multiple cancers. However, there is no evidence that CerSs are associated with pancreatic ductal carcinoma (PDAC). In the present study, we examined CerS expression in clinical tissue and conducted data mining to investigate the clinical significance of CerSs in the TCGA-PAAD database. We found that high CerS6 expression positively correlated with progression and predicted worse prognosis in PDAC patients, establishing CerS6 as a potential biomarker for PDAC. Furthermore, CerS6 promoted cell proliferation, colony formation and invasion by producing C16-ceramide and was required for tumor formation. Mechanistically, AKT1 interacted with and phosphorylated FOXP3 at S418, which decreased the binding of FOXP3 to the CERS6 promoter and in turn induced CerS6 expression by reconstituting an activated state on the CERS6 promoter. The AKT1/FOXP3 axis mediated the CerS6 expression and promoted p53 mutant pancreatic tumorigenesis by producing excessive C16-ceramide, which induced the accumulation of mutant p53. Thus, our study explores the relationship between PI3K/AKT signaling and sphingolipid metabolism, revealing an oncogenic role for CerS6, which may represent a potential target for PDAC treatment.
•AKT phosphorylates FoxP3 at S418, which impairs FoxP3 transcriptional activity.•Phosphorylation of FoxP3 at S418 alleviates its ability of suppressing CerS6 expression.•CerS6 produces C16-ceramide, which binds and stabilizes WT or mutant p53, thus, presents opposite effect on tumor cells.
PDF
