Malignant pleural effusion is a common complication in metastatic breast cancer (MBC); however, changes in the pleural microenvironment are poorly characterized, especially with respect to estrogen ...receptor status. Histologically, MBC presents with increased microvessels beneath the parietal and visceral pleura, indicating generalized angiogenic activity. Breast cancer‐associated pleural fluid (BAPF) was collected and cultured with HUVECs to recapitulate the molecular changes in subpleural endothelial cells. The clinical progression of triple‐negative breast cancer (TNBC) is much more aggressive than that of hormone receptor‐positive breast cancer (HPBC). However, BAPF from HPBC (BAPF‐HP) and TNBC (BAPF‐TN) homogeneously induced endothelial proliferation, migration, and angiogenesis. In addition, BAPF elicited negligible changes in the protein marker of endothelial‐mesenchymal transition. Both BAPF‐HP and BAPF‐TN exclusively upregulated JNK signaling among all MAPKs in HUVECs. By contrast, the response to the JNK inhibitor was insignificant in Transwell and tube formation assays of the HUVECs cultured with BAPF‐TN. The distinct contribution of p‐JNK to endothelial angiogenesis was consequently thought to be induced by BAPF‐HP and BAPF‐TN. Due to increased angiogenic factors in HUVECs cultured with BAPF, vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor was applied accordingly. Responses to VEGFR2 blockade were observed in both BAPF‐HP and BAPF‐TN concerning endothelial migration and angiogenesis. In conclusion, the above results revealed microvessel formation in the pleura of MBC and the underlying activation of p‐JNK/VEGFR2 signaling. Distinct responses to blocking p‐JNK and VEGFR2 in HUVECs cultured with BAPF‐HP or BAPF‐TN could lay the groundwork for future investigations in treating MBC based on hormone receptor status.
Current study evaluated the angiogenic response of HUVECs cultured with breast cancer‐associated pleural fluid (BAPF) obtained from hormone positive (HP) and triple negative (TN) breast cancer, respectively. Both BAPF‐HP and BAPF‐TN stimulated endothelial angiogenesis with upregulation of vascular endothelial growth factor receptor 2 (VEGFR2) and p‐JNK expressions. In contrast, application of p‐JNK inhibitor only showed efficacy in HUVECs cultured with BAPF‐HP, but not BAPF‐TN. Blockade of VEGFR2 signaling revealed potent inhibition on endothelial motility and angiogenesis induced by BAPF‐HP and BAPF‐TN.
'Autophagy' refers to an evolutionarily conserved process through which cellular contents, such as damaged organelles and protein aggregates, are delivered to lysosomes for degradation. Different ...forms of autophagy have been described on the basis of the nature of the cargoes and the means used to deliver them to lysosomes. At present, the prevailing categories of autophagy in mammalian cells are macroautophagy, microautophagy and chaperone-mediated autophagy. The molecular mechanisms and biological functions of macroautophagy and chaperone-mediated autophagy have been extensively studied, but microautophagy has received much less attention. In recent years, there has been a growth in research on microautophagy, first in yeast and then in mammalian cells. Here we review this form of autophagy, focusing on selective forms of microautophagy. We also discuss the upstream regulatory mechanisms, the crosstalk between macroautophagy and microautophagy, and the functional implications of microautophagy in diseases such as cancer and neurodegenerative disorders in humans. Future research into microautophagy will provide opportunities to develop novel interventional strategies for autophagy- and lysosome-related diseases.
Background and Purpose
Cancer cells exhibit more dependence on iron and enhanced sensitivity to iron‐dependent, programmed cell death (ferroptosis) than normal cells. Quercetin exerts anti‐cancer ...effects, but the underlying molecular mechanism is largely unknown. In this study, we aimed to investigate the involvement of lysosome function and ferroptosis in the anti‐cancer potential of quercetin.
Experimental Approach
We used MTT assays and DNA content analysis to evaluate the cytotoxicity, colony formation assay to investigate cell proliferation, and flow cytometry and confocal microscopy to detect lysosomal acidification and protease enzyme activity. Western blotting, cell subfractionation, RT‐PCR and siRNA transfection were used to establish molecular mechanisms of action.
Key Results
Quercetin is known to promote p53‐independent cell death in various cancer cell lines. Although quercetin induces autophagy, genetic silencing of Atg7 fails to affect quercetin‐induced cell death. In contrast, both lysosome inhibitors and knockdown of the transcription factor EB can prevent quercetin‐induced cell death, suggesting the involvement of lysosome. Next, quercetin is found to induce lysosomal activation sequentially through nuclear translocation of EB and transcriptional activation of lysosomal genes. Notably, quercetin promoted lysosome‐dependent ferritin degradation and free iron release. This action and quercetin‐induced ROS generation synergistically resulted in lipid peroxidation and ferroptosis. Furthermore, Bid may link ferroptosis with apoptosis to cause cell death.
Conclusion and Implications
Quercetin induced EB‐mediated lysosome activation and increased ferritin degradation leading to ferroptosis and Bid‐involved apoptosis. Results from this study may expand our current knowledge about the mechanism of quercetin as an anti‐cancer agent.
Based on hourly geostationary satellite temperature‐of‐black‐body data, 9,754 mesoscale convective systems (MCSs) are found to form over the Tibetan Plateau (TP) during 16 warm seasons. In the whole ...study period, neither the occurrence numbers of these MCSs nor their other key characteristics are found to have a significant trend of increasing/decreasing. The MCSs can form anywhere over the TP, and ~6.6% of them can move eastward and vacate the TP (defined as the eastward‐moving type EMT). The EMTs' mean occurrence frequency and lifespan are ~0.3 per day and ~12.0 hr, respectively. Compared to the MCSs that do not vacate the TP, the EMTs usually have stronger intensity, longer lifespan, and develop more rapidly but generate in a drier environment. The vacating stage of an EMT usually begins in the latter half of its lifespan, and an EMT tends to reach its maximum cloud area when it is about to vacate the TP. After vacating the TP, an EMT usually weakens at first and then enhances again. Vorticity budget indicates that the convergence‐related horizontal shrinking and the convection‐related vertical vorticity transport govern the cyclonic‐vorticity increase/maintenance associated with the longer‐lived EMTs. Of all the EMTs, only ~8% are associated with southwest vortices (SWVs), and the precipitation related to these EMTs contributes ~20% to the local hourly heavy precipitation. Compared to the EMTs that are not related to SWVs, those that are generally vacate the TP sooner, last longer having vacated the TP, and have longer whole lifespans.
A total of 9,754 mesoscale convective systems (MCSs) are found to form over the Tibetan Plateau (TP) during 16 warm seasons, with ~6.6% of them moving eastward and vacating the TP (the eastward‐moving type EMT). Compared to the MCSs that do not vacate the TP, the EMTs usually have stronger intensity, longer lifespan, and develop more rapidly but generate in a drier environment. The convergence‐related horizontal shrinking and convection‐related vertical vorticity transport govern the cyclonic‐vorticity increase/maintenance associated with the longer‐lived EMTs.
The coincidence and superposition of flood processes from different rivers and regions tend to form compound flood events, determined by spatial relationship between diverse flood processes that ...cannot be accurately depicted and evaluated by existing dependence analysis methods. A framework, integrating multi‐dimensional vine copula model and dependence evaluation system, was developed with a testing‐oriented application to explore underlying dependence between two kinds of extreme runoff series (peak discharge and flood volume) extracted from the identified compound flood events in the upper reaches of the Yangtze River. Multi‐dimensional regular vine (R‐vine) copula models were established to depict the complex and diverse dependence, and corresponding vine structure was specified by the vine structure array that can reflect the sequence of tributaries flowing into the main stream and the spatial locations of different hydrometric stations. Dependence magnitude and association status were calculated and compared according to the optimal R‐vine copula models and information theory. Comparison with existing methods demonstrated that dependence evaluation system could reflect nonlinear and local dependence characteristics and eliminate the effect of extreme runoff series from other hydrometric station on the dependence. The association status between different extreme runoff series of the upper Yangtze River and its tributaries were diverse in view of the impact of tributary flood inflow. The proposed framework can be regarded as an effective way for dependence modeling and evaluation of compound floods, thus providing a scientific reference for the risk analysis of water resources systems.
Key Points
Vine structure is specified by the sequence of tributaries flowing into main stream and spatial locations of hydrological stations
Dependence evaluation system determines dependence magnitude and association status through R‐statistic and interaction gain
Extreme runoff series of the same hydrometric station show distinct association status
Abstract
P2‐type layered oxide material Na
2/3
Ni
1/3
Mn
2/3
O
2
is a competitive candidate for sodium‐ion batteries (SIBs). Nevertheless, it suffers from the strong P2–O2 phase transition during ...charging to the high voltage regime, rendering drastic volume variations and poor cycling performance. Here, a Quasi‐zero strain P2‐Na
0.75
Li
0.15
Mg
0.05
Ni
0.1
Mn
0.7
O
2
cathode is synthesized, which reflects the vanishing P2–O2 transition with a volume change as low as 0.49%, thus resulting in the material an excellent cycling performance (83.9% capacity retention after 500 cycles at 5 C). The low‐volume strain can be attributed to two aspects: (1) the Mg
2+
riveted in the Na layer can act as a “pillar” to stabilize the crystal structure under the condition of sodium removal, thus restricting the structural changes under high voltage. (2) The entry of Li
+
into the transition metal (TM) layer can mitigate the electron localization in the highly desodiation state and can effectively immobilize the coordination oxygen atoms, thus suppressing the slip of P2–O2 transition. This study not only provides a new insight of Li and Mg synergetic substitution effect on the structural stability of P2‐type cathode, but also an efficient avenue for developing cathode materials of SIBs with ultralow bulk strain.
Mitophagy refers to the process of selective removal of damaged or superfluous mitochondria via the autophagy/lysosome pathway. In the past decade the molecular mechanisms underlying mitophagy have ...been extensively studied. It is now well established that the key mitophagy machinery undergoes extensive post-translational modifications (PTMs) such as phosphorylation/dephosphorylation, ubiquitination/deubiquitination, and acetylation/deacetylation that involve an array of enzymes including protein kinases/phosphatases, E3 ligases/deubiquitinases, acetyltransferases/deacetylases. In this review we provide a systematic summary of these key PTMs, and discuss the effectors and the functional implications of such PTMs in mitophagy-related diseases. Understanding PTM of the mitophagy machinery offers a unique window of opportunity for the discovery of novel mitophagy interventional strategies and for the control of mitophagy-related diseases.
Five main PTMs (phosphorylation, ubiquitination, acetylation, glycosylation, SUMOylation) as well as their respective reverse processes are involved in the regulation of mitophagy.Three kinases (PINK1, TBK1, and ULK1) mediate three amplification loops in the control of mitophagy.Crosstalk among the different forms of PTM determines the course of mitophagy.Targeting the PTMs of key mitophagy effectors offers opportunities for the development of novel interventional strategies for mitophagy and related diseases.
The cGAS‐STING pathway plays an important role in host defense by sensing pathogen DNA, inducing type I IFNs, and initiating autophagy. However, the molecular mechanism of autophagosome formation in ...cGAS‐STING pathway‐induced autophagy is still unclear. Here, we report that STING directly interacts with WIPI2, which is the key protein for LC3 lipidation in autophagy. Binding to WIPI2 is necessary for STING‐induced autophagosome formation but does not affect STING activation and intracellular trafficking. In addition, the specific interaction between STING and the PI3P‐binding motif of WIPI2 leads to the competition of WIPI2 binding between STING and PI3P, and mutual inhibition between STING‐induced autophagy and canonical PI3P‐dependent autophagy. Furthermore, we show that the STING‐WIPI2 interaction is required for the clearance of cytoplasmic DNA and the attenuation of cGAS‐STING signaling. Thus, the direct interaction between STING and WIPI2 enables STING to bypass the canonical upstream machinery to induce LC3 lipidation and autophagosome formation.
Synopsis
STING‐induced autophagy does not depend on ULK1 complex and PIK3C3 complex. Here, we report that STING directly interacts with WIPI2 and brings WIPI2 to STING‐positive vesicles. Our results reveal a mechanism by which WIPI2 is recruited to phagophore for LC3 lipidation and phagophore expansion during STING‐induced autophagosome formation.
STING brings WIPI2 to STING‐positive vesicles for autophagosome formation during STING‐induced autophagy.
STING and PI3P competitively bind to WIPI2, which leads to mutual inhibition between STING‐induced autophagy and PI3P‐dependent autophagy.
STING‐WIPI2 interaction is required for autophagy‐dependent clearance of cytoplasmic DNA and the attenuation of cGAS‐STING signaling.
STING interacts with the autophagy protein WIPI2 to promote autophagy‐dependent clearance of cytoplasmic DNA and the attenuation of cGAS‐STING signaling.
Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in sunscreens, food additives, pigments, rubber manufacture, and electronic materials. Several studies have shown that ZnO-NPs inhibit cell ...growth and induce apoptosis by the production of oxidative stress in a variety of human cancer cells. However, the anti-cancer property and molecular mechanism of ZnO-NPs in human gingival squamous cell carcinoma (GSCC) are not fully understood. In this study, we found that ZnO-NPs induced growth inhibition of GSCC (Ca9-22 and OECM-1 cells), but no damage in human normal keratinocytes (HaCaT cells) and gingival fibroblasts (HGF-1 cells). ZnO-NPs caused apoptotic cell death of GSCC in a concentration-dependent manner by the quantitative assessment of oligonucleosomal DNA fragmentation. Flow cytometric analysis of cell cycle progression revealed that sub-G1 phase accumulation was dramatically induced by ZnO-NPs. In addition, ZnO-NPs increased the intracellular reactive oxygen species and specifically superoxide levels, and also decreased the mitochondrial membrane potential. ZnO-NPs further activated apoptotic cell death via the caspase cascades. Importantly, anti-oxidant and caspase inhibitor clearly prevented ZnO-NP-induced cell death, indicating the fact that superoxide-induced mitochondrial dysfunction is associated with the ZnO-NP-mediated caspase-dependent apoptosis in human GSCC. Moreover, ZnO-NPs significantly inhibited the phosphorylation of ribosomal protein S6 kinase (p70S6K kinase). In a corollary in vivo study, our results demonstrated that ZnO-NPs possessed an anti-cancer effect in a zebrafish xenograft model. Collectively, these results suggest that ZnO-NPs induce apoptosis through the mitochondrial oxidative damage and p70S6K signaling pathway in human GSCC. The present study may provide an experimental basis for ZnO-NPs to be considered as a promising novel anti‑tumor agent for the treatment of gingival cancer.
Microwave-assisted extraction of flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja leaves, its chemical composition and antioxidant activity were investigated in this study. The influences of ...parameters including temperature, extraction time, ratio of material to solvent and solvents on the yield of flavonoids were studied. The optimal conditions were determined and the quadratic response surfaces were drawn from the mathematical models. The maximum extraction yield of 15.64 mg/g was achieved at temperature of 76.8 °C, extraction time of 15 min, alcohol concentration of 63.2% and ratio of solvent to material of 21.4:1. Five main constituents in the extract including quercetin-3-O-β-D-glucuronide, quercetin, kaempferol-3-O-β-D-glucuronide, kaempferol-7-O-α-L-rhamnoside and kaempferol were identified by LC-MS. In vitro antioxidant assays showed that the extract exhibited a strong DPPH radical-scavenging ability with IC50 value of 0.146 mg/mL. Results indicated that MAE was a suitable approach for the selective extraction of flavonoids from C. paliurus (Batal.) Iljinskaja leaves.
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