Oncogenic signals contribute to enhanced glycolysis and mTORC1 activity, leading to rapid cell proliferation in cancer. Regulation of glycolysis and mTORC1 by PI3K/Akt signaling is well established, ...but how KRAS‐induced MEK signaling regulates these pathways remains poorly understood. Here, we report a role for MEK‐driven lactate production in mTORC1 activation in KRAS‐activated cells. KRAS/MEK‐induced upregulation of the chicken ovalbumin upstream promoter transcriptional factor II (COUP‐TFII) increases the expression of lactate dehydrogenase A (LDHA), resulting in lactate production and mTORC1 activation. Further, lactate inhibits the interaction of TSC2 and Rheb, leading to the cellular activation of mTORC1 irrespective of growth factor stimulation. These findings suggest that COUP‐TFII is a novel oncogenic mediator, connecting KRAS signaling and glycolysis, and leading to mTORC1 activation and cellular growth.
Synopsis
The orphan nuclear receptor COUP‐TFII transmits KRAS‐induced oncogenic signals to promote glycolysis in cancer. KRAS/MEK‐dependent upregulation of COUP‐TFII increases LDHA expression, resulting in lactate production and mTORC1 activation.
COUP‐TFII contributes to enhanced glycolysis in KRAS activated cancer cells.
COUP‐TFII increases lactate production, leading to mTORC1 activation and cellular growth.
Lactate activates mTORC1 by interrupting TSC2‐Rheb interactions, independent of growth factor signals.
The orphan nuclear receptor COUP‐TFII transmits KRAS‐induced oncogenic signals to promote glycolysis in cancer. KRAS/MEK‐dependent upregulation of COUP‐TFII increases LDHA expression, resulting in lactate production and mTORC1 activation.
Chrysanthemum zawadskii var. latilobum (CZ) has been used as a traditional medicine in Asian countries for the treatment of inflammatory diseases. Recently, CZ extract was shown to inhibit ...differentiation of osteoclasts and provide protection against rheumatoid arthritis. The aim of this study was to investigate the molecular mechanisms of BST106, the ethanol extract of CZ, for cartilage protection in monosodium iodoacetate (MIA)-induced osteoarthritis (OA), particularly focusing on apoptosis and autophagy. BST106 (50, 100, and 200 mg/kg) was orally administered once daily to MIA-induced OA rats. Swelling, limping, roentgenography, and histomorphological changes were assessed 28 d after MIA injection. Biochemical parameters for matrix metalloproteinase (MMP), apoptosis, and autophagy were also assessed. BST106 ameliorated the severity of swelling and limping after MIA injection. Roentgenographic and histomorphological examinations revealed that BST106 reduced MIA-induced cartilage damage. BST106 decreased MIA-induced increases in MMP-2 and MMP-13 mRNA levels. Increased levels of serum cartilage oligomeric matrix protein and glycosaminoglycan release were attenuated by BST106. Furthermore, BST106 suppressed the protein expression of proapoptotic molecules and increased the protein expression of autophagosome- and autolysosome-related molecules. These findings indicate that BST106 protects against OA-induced cartilage damage by inhibition of the apoptotic pathway and restoration of impaired autophagic flux.
Despite its outstanding clinical success, immune checkpoint blockade remains ineffective in many patients. Accordingly, combination therapy capable of achieving greater antitumor immunity is urgently ...required. Here, we report that limiting glutamine metabolism in cancer cells bolsters the effectiveness of anti-programmed death ligand-1 (PD-L1) antibody. Inhibition of glutamine utilization increased PD-L1 levels in cancer cells, thereby inactivating co-cultured T cells. Under glutamine-limited conditions, reduced cellular GSH levels caused an upregulation of PD-L1 expression by impairing SERCA activity, which activates the calcium/NF-κB signaling cascade. Consequently, in tumors grown in immunocompetent mice, inhibition of glutamine metabolism decreased the antitumor activity of T cells. In combination with anti-PD-L1, however, glutamine depletion strongly promoted the antitumor efficacy of T cells in vitro and in vivo due to simultaneous increases in Fas/CD95 levels. Our results demonstrate the relevance of cancer glutamine metabolism to antitumor immunity and suggest that co-targeting of glutamine metabolism and PD-L1 represents a promising therapeutic approach.
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•Inhibition of glutamine utilization increases both PD-L1 and Fas expression•Reduced GSH levels upregulate PD-L1 expression by decreasing SERCA activity•Limiting glutamine availability increases anti-PD-L1–mediated T cell cytotoxicity•Co-targeting glutamine utilization and PD-L1 has a synergistic antitumor effect
Byun et al. demonstrated that upregulation of PD-L1 expression in cancer cells in a glutamine-poor tumor microenvironment dampens the antitumor properties of T cells, even though Fas-induced apoptosis signaling is upregulated. However, combined treatment with an inhibitor of glutamine utilization and anti-PD-L1 antibody significantly increased T-cell-mediated cancer cell death.
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•Deactivation of CuSSZ13 by aging becomes more severe as the Cu/Al ratio increases.•Cu2+ ions are first exchanged on the sites on D6R (α) before those in the CHA cage (β).•The β/α ...ratio reveals a rising trend with increasing Cu/Al ratio.•Cu2+ ions on the CHA sites readily agglomerate leading to the formation of CuOx.•Collapse of SSZ13 due to CuOx is the primary cause for the hydrothermal deactivation.
The hydrothermal stability of CuSSZ13 catalysts with respect to their Cu/Al ratio has been investigated to understand the deactivation mechanism of their catalytic activity for NO reduction by NH3/SCR. The decline of the deNOx activity due to the hydrothermal aging became more severe as the Cu/Al ratio increased. Results of ESR, H2-TPR and DRIFT studies indicated that the D6R sites are occupied first by Cu2+ ions (α species) up to their accommodation capacity, followed by the occupation of the CHA sites (β species) with the increase in the Cu/Al ratio. The β species agglomerate more readily than α species due to their less stable nature, leading to the formation of CuOx. The CuOx may grow to destroy the zeolite cage and channel, resulting in the collapse of the SSZ13 structure, which is believed to be the primary cause for the hydrothermal deactivation of the CuSSZ13 catalyst.
Achieving satisfactory bone tissue regeneration in osteoporotic patients with ordinary biomaterials is challenging because of the decreased bone mineral density and aberrant bone microenvironment. In ...addressing this issue, a biomimetic scaffold (PMEH/SP), incorporating 4‐hexylresorcinol (4HR), and substance P (SP) into the poly(lactic‐go‐glycolic acid) (PLGA) scaffold with magnesium hydroxide (M) and extracellular matrix (E) is introduced, enabling the consecutive release of bioactive agents. 4HR and SP induced the phosphorylation of p38 MAPK and ERK in human umbilical vein endothelial cells (HUVECs), thereby upregulating VEGF expression level. The migration and tube‐forming ability of endothelial cells can be promoted by the scaffold, which accelerates the formation and maturation of the bone. Moreover, 4HR played a crucial role in the inhibition of osteoclastogenesis by interrupting the IκB/NF‐κB signaling pathway and exhibiting SP, thereby enhancing the migration and angiogenesis of HUVECs. Based on such a synergistic effect, osteoporosis can be suppressed, and bone regeneration can be achieved by inhibiting the RANKL pathway in vitro and in vivo, which is a commonly known mechanism of bone physiology. Therefore, the study presents a promising approach for developing a multifunctional regenerative material for sophisticated osteoporotic bone regeneration.
A novel biomimetic scaffold incorporating 4‐hexylresorcinol and substance p is prepared for osteoporotic bone regeneration. It controls the sequential release of bioactive agents. This promotes VEGF expressions and enhances cell migration, tube‐formation, and facilitating bone formation. Additionally, it inhibits osteoclastogenesis by interrupting the IκB/NF‐κB signaling pathway. The study demonstrates a promising multifunctional scaffold for sophisticated osteoporotic bone regeneration.
Background There is no standardization of the use of suction during puncturing of a target in pancreatic EUS-guided FNA (EUS-FNA). It is also debatable whether expressing aspirates from the needle by ...the traditional method of reinserting the stylet is more effective than by air flushing, which is easier and safer. Objective To optimize sampling techniques in pancreatic EUS-FNA. Design Prospective, comparative trial. Setting Tertiary-care referral center. Patients Eighty-one consecutive patients with solid pancreatic masses. Intervention Four punctures were performed for each mass in random order by a 2 × 2 factorial design. Sample quality and diagnostic yield were compared between samples with suction (S+) versus no suction (S-) and expressed by reinserting the stylet (RS) versus air flushing (AF). Main Outcome Measurements Sample quality by the number of diagnostic samples, cellularity, bloodiness, and air-drying artifact; diagnostic yield by accuracy, sensitivity, and specificity. Results The number of diagnostic samples (72.8% vs 58.6%; P = .001), cellularity (odds ratio OR 2.12; 95% confidence interval CI, 1.37-3.30; P < .001), bloodiness (OR 1.46; CI, 1.28-1.68; P < .001), accuracy (85.2% vs 75.9%; P = .004), and sensitivity (82.4% vs 72.1%; P = .005) were higher in S+ than in S-. Bloodiness was lower in AF than in RS (OR 1.16; CI, 1.03-1.30; P = .017). Limitations Single-center trial, 2 kinds of needle gauges, and no immediate cytopathology evaluation. Conclusion Puncturing with suction and expressing by air flushing may be used preferentially in pancreatic EUS-FNA because they were more effective and convenient techniques. (Clinical trial registration number: NCT01354795 .)
Macropinocytosis, an important nutrient-scavenging pathway in certain cancer cells, allows cells to compensate for intracellular amino acid deficiency under nutrient-poor conditions. Ferroptosis ...caused by cysteine depletion plays a pivotal role in sorafenib responses during hepatocellular carcinoma (HCC) therapy. However, it is not known whether macropinocytosis functions as an alternative pathway to acquire cysteine in sorafenib-treated HCC, and whether it subsequently mitigates sorafenib-induced ferroptosis. This study aimed to investigate whether sorafenib drives macropinocytosis induction, and how macropinocytosis confers ferroptosis resistance on HCC cells.
Macropinocytosis, both in HCC cells and HCC tissues, was evaluated by measuring TMR-dextran uptake or lysosomal degradation of DQ-BSA, and ferroptosis was evaluated via C11-BODIPY fluorescence and 4-HNE staining. Sorafenib-induced ferroptosis and macropinocytosis were validated in tumor tissues taken from HCC patients who underwent ultrasound-guided needle biopsy.
Sorafenib increased macropinocytosis in human HCC specimens and xenografted HCC tissues. Sorafenib-induced mitochondrial dysfunction was responsible for activation of PI3K-RAC1-PAK1 signaling, and amplified macropinocytosis in HCC. Importantly, macropinocytosis prevented sorafenib-induced ferroptosis by replenishing intracellular cysteine that was depleted by sorafenib treatment; this rendered HCC cells resistant to sorafenib. Finally, inhibition of macropinocytosis by amiloride markedly enhanced the anti-tumor effect of sorafenib, and sensitized resistant tumors to sorafenib.
In summary, sorafenib induced macropinocytosis, which conferred drug resistance by mitigating sorafenib-induced ferroptosis. Thus, targeting macropinocytosis is a promising therapeutic strategy to facilitate ferroptosis-based therapy for HCC.
Emerging new mutations after treatment can provide clues to acquired resistant mechanisms. Circulating tumor DNA (ctDNA) sequencing has enabled noninvasive repeated tumor mutational profiling. We ...aimed to investigate newly emerging mutations in ctDNA after disease progression in metastatic colorectal cancer (mCRC). Blood samples were prospectively collected from mCRC patients receiving palliative chemotherapy before treatment and at radiological evaluations. ctDNA from pretreatment and progressive disease (PD) samples were sequenced with a next‐generation sequencing panel targeting 106 genes. A total of 712 samples from 326 patients were analyzed, and 381 pretreatment and PD pairs (163 first‐line, 85 second‐line and 133 later‐line ≥third‐line) were compared. New mutations in PD samples (mean 2.75 mutations/sample) were observed in 49.6% (189/381) of treatments. ctDNA samples from later‐line had more baseline mutations (P = .002) and were more likely to have new PD mutations (adjusted odds ratio OR 2.27, 95% confidence interval CI: 1.40‐3.69) compared to first‐line. RAS/BRAF wild‐type tumors were more likely to develop PD mutations (adjusted OR 1.87, 95% CI: 1.22‐2.87), independent of cetuximab treatment. The majority of new PD mutations (68.5%) were minor clones, suggesting an increasing clonal heterogeneity after treatment. Pathways involved by PD mutations differed by the treatment received: MAPK cascade (Gene Ontology GO: 0000165) in cetuximab and regulation of kinase activity (GO: 0043549) in regorafenib. The number of mutations revealed by ctDNA sequencing increased during disease progression in mCRC. Clonal heterogeneity increased after chemotherapy progression, and pathways involved were affected by chemotherapy regimens.
What's new?
Mutations that arise during treatment for metastatic colorectal cancer (mCRC) can fuel the development of treatment‐resistant tumors. Tracking the mutational evolution of mCRC, however, is challenged by limitations in existing approaches. Here, the authors investigated newly emerging mutations by sequencing circulating tumor DNA (ctDNA) from progressive mCRC patients following conventional treatments. Mutations that emerged in association with treatment were identified in half of progressive disease samples. New mutations were dominantly subclonal variants and were more frequently observed in later‐line treatments and RAS/BRAF wild‐type tumors. The findings cast new light on relationships between emergent mutations and treatment in progressive mCRC.
The metabolism of glutamine and glucose is recognized as a promising therapeutic target for the treatment of cancer; however, targeted molecules that mediate glutamine and glucose metabolism in ...cancer cells have not been addressed. Here, we show that restricting the supply of glutamine in hepatoma cells, including HepG2 and Hep3B cells, markedly increased the expression of retinoic acid‐related orphan receptor alpha (RORα). Up‐regulation of RORα in glutamine‐deficient hepatoma cells resulted from an increase in the level of cellular reactive oxygen species and in the nicotinamide adenine dinucleotide phosphate/nicotinamide adenine dinucleotide phosphate reduced (NADP+/NADPH) ratio, which was consistent with a reduction in the glutathione/glutathione disulfide (GSH/GSSG) ratio. Adenovirus (Ad)‐mediated overexpression of RORα (Ad‐RORα) or treatment with the RORα activator, SR1078, reduced aerobic glycolysis and down‐regulated biosynthetic pathways in hepatoma cells. Ad‐RORα and SR1078 reduced the expression of pyruvate dehydrogenase kinase 2 (PDK2) and inhibited the phosphorylation of pyruvate dehydrogenase and subsequently shifted pyruvate to complete oxidation. The RORα‐mediated decrease in PDK2 levels was caused by up‐regulation of p21, rather than p53. Furthermore, RORα inhibited hepatoma growth both in vitro and in a xenograft model in vivo. We also found that suppression of PDK2 inhibited hepatoma growth in a xenograft model. These findings mimic the altered glucose utilization and hepatoma growth caused by glutamine deprivation. Finally, tumor tissue from 187 hepatocellular carcinoma patients expressed lower levels of RORα than adjacent nontumor tissue, supporting a potential beneficial effect of RORα activation in the treatment of liver cancer. Conclusion: RORα mediates reprogramming of glucose metabolism in hepatoma cells in response to glutamine deficiency. The relationships established here between glutamine metabolism, RORα expression and signaling, and aerobic glycolysis have implications for therapeutic targeting of liver cancer metabolism. (Hepatology 2015;61:953–964)
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