Elevated Kallistatin promotes the occurrence and progression of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and the development of non-alcoholic steatohepatitis (NASH) might cause irreversible hepatic damage. Hyperlipidemia (HLP) is the leading risk factor for NAFLD. This study aims to illuminate the causative contributor and potential mechanism of Kallistatin (KAL) mediating HLP to NAFLD. 221 healthy control and 253 HLP subjects, 62 healthy control and 44 NAFLD subjects were enrolled. The plasma KAL was significantly elevated in HLP subjects, especially in hypertriglyceridemia (HTG) subjects, and positively correlated with liver injury. Further, KAL levels of NAFLD patients were significantly up-regulated. KAL transgenic mice induced hepatic steatosis, inflammation, and fibrosis with time and accelerated inflammation development in high-fat diet (HFD) mice. In contrast, KAL knockout ameliorated steatosis and inflammation in high-fructose diet (HFruD) and methionine and choline-deficient (MCD) diet-induced NAFLD rats. Mechanistically, KAL induced hepatic steatosis and NASH by down-regulating adipose triglyceride lipase (ATGL) and comparative gene identification 58 (CGI-58) by LRP6/Gɑs/PKA/GSK3ß pathway through down-regulating peroxisome proliferator-activated receptor γ (PPARγ) and up-regulating kruppel-like factor four (KLF4), respectively. CGI-58 is bound to NF-κB p65 in the cytoplasm, and diminishing CGI-58 facilitated p65 nuclear translocation and TNFα induction. Meanwhile, hepatic CGI-58-overexpress reverses NASH in KAL transgenic mice. Further, free fatty acids up-regulated KAL against thyroid hormone in hepatocytes. Moreover, Fenofibrate, one triglyceride-lowering drug, could reverse hepatic steatosis by down-regulating KAL. These results demonstrate that elevated KAL plays a crucial role in the development of HLP to NAFLD and may be served as a potential preventive and therapeutic target.

Kallistatin leads to cognition impairment via downregulating glutamine synthetase.

In many neurodegenerative disorders, such as Alzheimer's disease (AD), glutamate-mediated neuronal excitotoxicity is considered the basis for cognitive impairment. The mRNA and protein expression of SERPINA4(Kallistatin) are higher in patients with AD. However, whether Kallistatin plays a regulatory role in glutamate-glutamine cycle homeostasis remains unclear. In this study, we identified impaired cognitive function in Kallistatin transgenic (KAL-TG) mice. Baseline glutamate levels were elevated and miniature excitatory postsynaptic current (mEPSC) frequency was increased in the hippocampus, suggesting the impairment of glutamate homeostasis in KAL-TG mice. Mechanistically, we demonstrated that Kallistatin promoted lysine acetylation and ubiquitination of glutamine synthetase (GS) and facilitated its degradation via the proteasome pathway, thereby downregulating GS. Fenofibrate improved cognitive memory in KAL-TG mice by downregulating serum Kallistatin. Collectively, our study findings provide insights the mechanism by which Kallistatin regulates cognitive impairment, and suggest the potential of fenofibrate to prevente and treat of AD patients with high levels of Kallistatin.

Macrophages Promote Subtype Conversion and Endocrine Resistance in Breast Cancer.

BACKGROUND: The progression of tumors from less aggressive subtypes to more aggressive states during metastasis poses challenges for treatment strategies. Previous studies have revealed the molecular subtype conversion between primary and metastatic tumors in breast cancer (BC). However, the subtype conversion during lymph node metastasis (LNM) and the underlying mechanism remains unclear. METHODS: We compared clinical subtypes in paired primary tumors and positive lymph nodes (PLNs) in BC patients and further validated them in the mouse model. Bioinformatics analysis and macrophage-conditioned medium treatment were performed to investigate the role of macrophages in subtype conversion. RESULTS: During LNM, hormone receptors (HRs) were down-regulated, while HER2 was up-regulated, leading to the transformation of luminal A tumors towards luminal B tumors and from luminal B subtype towards HER2-enriched (HER2-E) subtype. The mouse model demonstrated the elevated levels of HER2 in PLN while retaining luminal characteristics. Among the various cells in the tumor microenvironment (TME), macrophages were the most clinically relevant in terms of prognosis. The treatment of a macrophage-conditioned medium further confirmed the downregulation of HR expression and upregulation of HER2 expression, inducing tamoxifen resistance. Through bioinformatics analysis, MNX1 was identified as a potential transcription factor governing the expression of HR and HER2. CONCLUSION: Our study revealed the HER2-E subtype conversion during LNM in BC. Macrophages were the crucial cell type in TME, inducing the downregulation of HR and upregulation of HER2, probably via MNX1. Targeting macrophages or MNX1 may provide new avenues for endocrine therapy and targeted treatment of BC patients with LNM.

Regulation of Hot Electrons Transport Achieved through Controlled Electron-Phonon Coupling in Metallic Heterostructures.

The electron-phonon (e-ph) interactions are pivotal in shaping the electrical and thermal properties, and in particular, determining the carrier dynamics and transport behaviors in optoelectronic devices. By employing pump-probe spectroscopy and ultrafast microscopy, the consequential role of e-ph coupling strength in the spatiotemporal evolution of hot electrons is elucidated. Thermal transport across the metallic interface is controlled to regulate effective e-ph coupling factor Geff in Au and Au/Cr heterostructure, and their impact on nonequilibrium transport of hot electrons is examined. Via the modulation of buried Cr thickness, a strong correlation between Geff and the diffusive behavior of hot electrons is found. By enhancing Geff through the regulation of thermal transport across interface, there is a significant reduction in e-ph thermalization time, the maximum diffusion length of hot electrons, and lattice heated area which are extracted from the spatiotemporal evolution profiles. Therefore, the increased Geff significantly weakens the diffusion of hot electrons and promotes heat relaxation of electron subsystems in both time and space. These insights propose a robust framework for spatiotemporal investigations of G impact on hot electron diffusion, underscoring its significance in the rational design of advanced optoelectronic devices with high efficiency.

The pathogenic role of succinate-SUCNR1: a critical function that induces renal fibrosis via M2 macrophage.

BACKGROUND: Renal fibrosis significantly contributes to the progressive loss of kidney function in chronic kidney disease (CKD), with alternatively activated M2 macrophages playing a crucial role in this progression. The serum succinate level is consistently elevated in individuals with diabetes and obesity, both of which are critical factors contributing to CKD. However, it remains unclear whether elevated succinate levels can mediate M2 polarization of macrophages and contribute to renal interstitial fibrosis. METHODS: Male C57/BL6 mice were administered water supplemented with 4% succinate for 12 weeks to assess its impact on renal interstitial fibrosis. Additionally, the significance of macrophages was confirmed in vivo by using clodronate liposomes to deplete them. Furthermore, we employed RAW 264.7 and NRK-49F cells to investigate the underlying molecular mechanisms. RESULTS: Succinate caused renal interstitial macrophage infiltration, activation of profibrotic M2 phenotype, upregulation of profibrotic factors, and interstitial fibrosis. Treatment of clodronate liposomes markedly depleted macrophages and prevented the succinate-induced increase in profibrotic factors and fibrosis. Mechanically, succinate promoted CTGF transcription via triggering SUCNR1-p-Akt/p-GSK3ß/ß-catenin signaling, which was inhibited by SUCNR1 siRNA. The knockdown of succinate receptor (SUCNR1) or pretreatment of anti-CTGF(connective tissue growth factor) antibody suppressed the stimulating effects of succinate on RAW 264.7 and NRK-49F cells. CONCLUSIONS: The causative effects of succinate on renal interstitial fibrosis were mediated by the activation of profibrotic M2 macrophages. Succinate-SUCNR1 played a role in activating p-Akt/p-GSK3ß/ß-catenin, CTGF expression, and facilitating crosstalk between macrophages and fibroblasts. Our findings suggest a promising strategy to prevent the progression of metabolic CKD by promoting the excretion of succinate in urine and/or using selective antagonists for SUCNR1.

The critical role of BTRC in hepatic steatosis as an ATGL E3 ligase.

Non-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis, is one of the commonest causes of liver dysfunction. Adipose triglyceride lipase (ATGL) is closely related to lipid turnover and hepatic steatosis as the speed-limited triacylglycerol lipase in liver lipolysis. However, the expression and regulation of ATGL in NAFLD remain unclear. Herein, our results showed that ATGL protein levels were decreased in the liver tissues of high-fat diet (HFD)-fed mice, naturally obese mice, and cholangioma/hepatic carcinoma patients with hepatic steatosis, as well as in the oleic acid-induced hepatic steatosis cell model, while ATGL mRNA levels were not changed. ATGL protein was mainly degraded through the proteasome pathway in hepatocytes. Beta-transducin repeat containing (BTRC) was upregulated and negatively correlated with the decreased ATGL level in these hepatic steatosis models. Consequently, BTRC was identified as the E3 ligase for ATGL through predominant ubiquitination at the lysine 135 residue. Moreover, adenovirus-mediated knockdown of BTRC ameliorated steatosis in HFD-fed mouse livers and oleic acid-treated liver cells via upregulating the ATGL level. Taken together, BTRC plays a crucial role in hepatic steatosis as a new ATGL E3 ligase and may serve as a potential therapeutic target for treating NAFLD.

PEDF protects retinal pigment epithelium from ferroptosis and ameliorates dry AMD-like pathology in a murine model.

Age-related macular degeneration (AMD) is the leading cause of irreversible vision damage among elderly individuals. There is still no efficient treatment for dry AMD. Retinal pigment epithelial (RPE) degeneration has been confirmed to play an important role in dry AMD. Recent studies have reported that ferroptosis caused by iron overload and lipid peroxidation may be the primary causes of RPE degeneration. However, the upstream regulatory molecules of RPE ferroptosis remain largely unknown. Pigment epithelium-derived factor (PEDF) is an important endogenic protective factor for the RPE. Our results showed that in the murine dry AMD model induced by sodium iodate (SI), PEDF expression was downregulated. Moreover, dry AMD-like pathology was observed in PEDF-knockout mice. Therefore, the aim of this study was to reveal the effects and mechanism of PEDF on RPE ferroptosis and investigate potential therapeutic targets for dry AMD. The results of lipid peroxidation and transmission electron microscope showed that retinal ferroptosis was significantly activated in SI-treated mice and PEDF-knockout mice. Restoration of PEDF expression ameliorated SI-induced retinal dysfunction in mice, as assessed by electroretinography and optical coherence tomography. Mechanistically, western blotting and immunofluorescence analysis demonstrated that the overexpression of PEDF could upregulate the expression of glutathione peroxidase 4 (GPX4) and ferritin heavy chain-1 (FTH1), which proved to inhibit lipid peroxidation and RPE ferroptosis induced by SI. This study revealed the novel role of PEDF in ferroptosis inhibition and indicated that PEDF might be a potential therapeutic target for dry AMD.

Kallistatin Deficiency Induces the Oxidative Stress-Related Epithelial-Mesenchymal Transition of Retinal Pigment Epithelial Cells: A Novel Protagonist in Age-Related Macular Degeneration.

Purpose: Retinal pigment epithelium (RPE) dysfunction induced by oxidative stress-related epithelial-mesenchymal transition (EMT) of RPE is the primary underlying mechanism of age-related macular degeneration (AMD). Kallistatin (KAL) is a secreted protein with an antioxidative stress effect. However, the relationship between KAL and EMT in RPE has not been determined. Therefore we aimed to explore the impact and mechanism of KAL in oxidative stress-induced EMT of RPE. Methods: Sodium iodate (SI) was injected intraperitoneally to construct the AMD rat model and investigate the changes in RPE morphology and KAL expression. KAL knockout rats and KAL transgenic mice were used to explain the effects of KAL on EMT and oxidative stress. In addition, Snail overexpressed adenovirus and si-RNA transfected ARPE19 cells to verify the involvement of Snail in mediating KAL-suppressed EMT of RPE. Results: AMD rats induced by SI expressed less KAL in the retina, and KAL knockout rats showed RPE dysfunction spontaneously where EMT and reactive oxygen species (ROS) production increased in RPE. In contrast, KAL overexpression attenuated EMT and ROS levels in RPE, even in TGF-ß treatment. Mechanistically, Snail reversed the beneficial effect of KAL on EMT and ROS reduction. Moreover, KAL ameliorated SI-induced AMD-like pathological changes. Conclusions: Our findings demonstrated that KAL inhibits oxidative stress-induced EMT by downregulating the transcription factor Snail. Herein, KAL knockout rats may be an appropriate animal model for observing spontaneous RPE dysfunction for AMD-like retinopathy, and KAL may represent a novel therapeutic target for treating dry AMD.

Pigment Epithelium-Derived Factor, a Novel Adipokine, Contributes to Gestational Diabetes Mellitus.

CONTEXT: Excessive insulin resistance, inadequate insulin compensation, or both could result in gestational diabetes mellitus (GDM). Levels of pigment epithelium-derived factor (PEDF), a novel adipokine that could induce insulin resistance, are high in patients with obesity and diabetes. However, the impact of PEDF in pregnancy remains unknown. OBJECTIVE: This study aimed to elucidate the role of PEDF on insulin resistance and compensatory elevation of insulin levels during normal pregnancy and in patients with GDM. METHODS: In this population-based and cohort study, logistic regression analysis was performed to determine the association of PEDF/adiponectin/leptin levels with the risk of developing GDM and to predict postpartum prediabetes. PEDF protein, PEDF transgenic mice, PEDF knockout mice, and PEDF-neutralized antibodies were used to observe changes in insulin resistance and insulin levels with pregnancy. RESULTS: Plasma PEDF levels were increased in normal pregnancy and higher in GDM women. Higher PEDF levels were associated with the increased risk of developing GDM and emerged as a significant independent determinant of postpartum prediabetes in GDM women. Mechanistically, in vivo and in vitro experiments revealed that PEDF induced insulin resistance by inhibiting the insulin signaling pathway. CONCLUSION: In addition to insulin resistance and upregulated insulin levels in normal pregnancy and GDM, aberrant PEDF levels can serve as a "fingerprint" of metabolic abnormalities during pregnancy. Thus, PEDF is a valuable biomarker but could interfere with the time course for early diagnosis and prognosis of GDM.

Inhibition of extranodal NK/T-cell lymphoma by Chiauranib through an AIF-dependent pathway and its synergy with L-asparaginase.

Extranodal NK/T-cell lymphoma (NKTL) is a rare and aggressive form of extranodal lymphoma with a poor prognosis. Currently, there are very limited treatment options for patients with advanced-stage disease or those with relapsed/recurrent disease. Here we show that Chiauranib, an orally small molecule inhibitor of select serine-threonine kinases (aurora B, VEGFRs, PDGFR, CSF1R, c-Kit), inhibited NKTL cell proliferation, induced cell cycle arrest, as well as suppressed the microvessel density in vitro and in vivo similar as in other types of cancer cells. Surprisingly, Chiauranib unfolded a new effect to induce apoptosis of NKTL cells by triggering AIF-dependent apoptosis other than the traditional cyt-c/caspase mitochondrial apoptosis pathway. The knockdown of AIF in vitro and in vivo dramatically blocked the efficacy of Chiauranib on NKTL. Mechanistically, the release of AIF from mitochondria is due to the upregulation of VDAC1 by the AKT-GSK3ß pathway and activation of calcium-dependent m-calpain, which promotes the cleavage of VDAC1 and therefore permits the release of AIF. Notably, the low expression of Bax in both NKTL cells and patient tissues restrained the cyt-c release. It resulted in the inhibition of cyt-c/caspase mitochondrial pathway, suggesting that drugs targeting this traditional pathway may not be effective in NKTL. Furthermore, we found that L-asparaginase triggered CD95 (Fas/Apo-1)-caspase 8-caspase 3 apoptotic pathway in NKTL cells, and combination of Chiauranib and L-asparaginase exhibited a synergistic effect, suggesting a feasibility to combine these two drugs for effective treatment of NKTL. This study demonstrates Chiauranib's positive efficacy toward NKTL through the activation of the AIF-dependent apoptosis pathway for the first time. The novel and multi-targets of Chiauranib and the synergistic effect with L-asparaginase may provide a promising therapy for NKTL patients.

N-cadherin cleavage: A critical function that induces diabetic retinopathy fibrosis via regulation of ß-catenin translocation.

Retinal fibrosis is a severe pathological change in the late stage of diabetic retinopathy and is also the leading cause of blindness. We have previously revealed that N-cadherin was significantly increased in type 1 and type 2 diabetic mice retinas and the fibrovascular membranes from proliferative diabetic retinopathy (PDR) patients. However, whether N-cadherin directly induces retinal fibrosis in DR and the related mechanism is unknown. Here, we investigated the pathogenic role of N-cadherin in mediating retinal fibrosis and further explored the relevant therapeutic targets. We found that the level of N-cadherin was significantly increased in PDR patients and STZ-induced diabetic mice and positively correlated with the fibrotic molecules Connective Tissue Growth Factor (CTGF) and fibronectin (FN). Moreover, intravitreal injection of N-cadherin adenovirus significantly increased the expression of FN and CTGF in normal mice retinas. Mechanistically, overexpression of N-cadherin promotes N-cadherin cleavage, and N-cadherin cleavage can further induce translocation of non-p-ß-catenin in the nucleus and upregulation of fibrotic molecules. Furthermore, we found a novel N-cadherin cleavage inhibitor, pigment epithelial-derived factor (PEDF), which ameliorated the N-cadherin cleavage and subsequent retinal fibrosis in diabetic mice. Thus, our findings provide novel evidence that elevated N-cadherin level not only acts as a classic EMT maker but also plays a causative role in diabetic retinal fibrosis, and targeting N-cadherin cleavage may provide a strategy to inhibit retinal fibrosis in DR patients.

Unconventional Shrinkage of Hot Electron Distribution in Metal Directly Visualized by Ultrafast Imaging.

Elucidation of hot carrier transport and cooling mechanisms at the micro-/nanoscale is critical for optoelectronics, thermal management, and photocatalysis. Spatiotemporal evolution of hot electrons is usually convoluted with their ultrafast dynamics. Herein, an ultrafast microscopy is employed to directly track the spatiotemporal distribution of photoexcited hot electrons, providing a transformative approach to unravel the competitive relationship of transport and cooling. In the temporal evolution profiles of hot electron distribution, an anomalous contracting stage showing obvious thickness and fluence dependency is observed, with a characteristic end time indicating the completion of electron-phonon (e-ph) thermalization. Hot electron transport plays a prominent role in the competition with e-ph coupling, while interfacial heat dissipation dominates nonequilibrium state evolution with thickness below ballistic length. This work significantly enriches the tool kit of ultrafast techniques and provides guidance for rational design and optimization of micro-/nanodevices.

Succinate-SUCNR1 induces renal tubular cell apoptosis.

Succinate has long been known to be only an intermediate product of the tricarboxylic acid cycle until identified as a natural ligand for SUCNR1 in 2004. SUCNR1 is widely expressed throughout the body, especially in the kidney. Abnormally elevated succinate is associated with many diseases, including obesity, type 2 diabetes, nonalcoholic fatty liver disease, and ischemia injury, but it is not known whether succinate can cause kidney damage. This study showed that succinate induced apparent renal injury after treatment for 12 wk, characterized by a reduction in 24 h urine and the significant detachment of the brush border of proximal tubular epithelial cells, tubular dilation, cast formation, and vacuolar degeneration of tubular cells in succinate-treated mice. Besides, succinate caused tubular epithelial cell apoptosis in kidneys and HK-2 cells. Mechanistically, succinate triggered cell apoptosis via SUCNR1 activation. In addition, succinate upregulated ERK by binding to SUCNR1, and inhibition of ERK using PD98059 abolished the proapoptotic effects of succinate in HK-2 cells. In summary, our study provides the first evidence that succinate acts as a risk factor and contributes to renal injury, and further research is required to discern the pathological effects of succinate on renal functions.

IL25 Enhanced Colitis-Associated Tumorigenesis in Mice by Upregulating Transcription Factor GLI1.

Interleukin-25 (IL17E/IL25) plays a critical role in colitis and intestinal homeostasis. However, the expression and biological role of IL25 in colorectal cancer is not properly understood. In this study, we show that IL25 is mainly expressed by cancer stem cells in the colorectal cancer microenvironment. Genetic deletion of IL25 inhibited tumor formation and growth and prolonged survival in AOM/DSS-treated mice. IL25 stimulated cancer organoid and cancer cells sphere formation and prevented the tumor from chemotherapy-induced apoptosis. Mechanistically, IL25 upregulated stem cell genes LGR5, CD133, and ABC transporters via activating the Hedgehog signaling pathway. IL25 inhibited phosphorylation of AMPK and promoted GLI1 accumulation to maintain cancer stem cells. Moreover, IL25 expression was associated with poor survival in patients with metastatic colorectal cancer. Taken together, our work reveals an immune-associated mechanism that intrinsically confers cancer cell stemness properties. Our results first demonstrated that IL25, as a new potent endogenous Hedgehog pathway agonist, could be an important prognostic factor and therapeutic target for CRC.

A role for Snail-MnSOD axis in regulating epithelial-to-mesenchymal transition markers expression in RPE cells.

Age-related macular degeneration (AMD) is a common cause of vision loss. The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells, accompanied by oxidative damage, plays a crucial role in AMD. It is well known that manganese superoxide dismutase (MnSOD) encoded by SOD2 is a critical molecule in fighting against oxidative stress, and Snail encoded by SNAI1 is the essential transcription factor for EMT. However, the effect of MnSOD on EMT and the underlying mechanism in RPE cells remains unknown. In this study, we found that MnSOD knockdown triggered the EMT by upregulating Snail, while MnSOD overexpression reversed EMT even with TGFß treatment in RPE cells, and the anti-oxidative stress activity of MnSOD mediated this observation. In addition, Snail depletion increased both expression and activity of MnSOD while Snail overexpression decreased MnSOD expression and activity, and Dual-luciferase reporter and ChIP assays showed that Snail directly bound to E-box (CACCTG) in the SOD2 promoter. Moreover, MnSOD over-expression and Snail interference co-treatment strengthened the anti-oxidation and EMT reversing. Therefore, our findings demonstrate that MnSOD prevents EMT of RPE cells in AMD through inhibiting oxidative injury to RPE. Moreover, a critical EMT transcription factor, Snail, functions as a new negative transcriptional factor of SOD2. Herein, the Snail-MnSOD axis forms a mutual loop in the development of AMD, which may be a novel systemic treatment target for preventing AMD.

IL-25-induced shifts in macrophage polarization promote development of beige fat and improve metabolic homeostasis in mice.

Beige fat dissipates energy and functions as a defense against cold and obesity, but the mechanism for its development is unclear. We found that interleukin (IL)-25 signaling through its cognate receptor, IL-17 receptor B (IL-17RB), increased in adipose tissue after cold exposure and ß3-adrenoceptor agonist stimulation. IL-25 induced beige fat formation in white adipose tissue (WAT) by releasing IL-4 and IL-13 and promoting alternative activation of macrophages that regulate innervation and up-regulate tyrosine hydroxylase (TH) up-regulation to produce more catecholamine including norepinephrine (NE). Blockade of IL-4Rα or depletion of macrophages with clodronate-loaded liposomes in vivo significantly impaired the beige fat formation in WAT. Mice fed with a high-fat diet (HFD) were protected from obesity and related metabolic disorders when given IL-25 through a process that involved the uncoupling protein 1 (UCP1)-mediated thermogenesis. In conclusion, the activation of IL-25 signaling in WAT may have therapeutic potential for controlling obesity and its associated metabolic disorders.

FUBP1 promotes colorectal cancer stemness and metastasis via DVL1-mediated activation of Wnt/ß-catenin signaling.

Distant metastasis is, unfortunately, the leading cause of death in colorectal cancer (CRC). Approximately 50% of CRC patients develop liver metastases, while 10-30% of patients develop pulmonary metastases. The occurrence of metastasis is considered to be almost exclusively driven by cancer stem cells (CSCs) formation. However, the key molecules that confer the transformation to stem cells in CRC, and subsequent metastasis, remain unclear. Far upstream element-binding protein 1 (FUBP1), a transcriptional regulator of c-Myc, was screened in CSCs of CRC by mass spectrometry and was examined by immunohistochemistry in a cohort of CRC tissues. FUBP1 was upregulated in 85% of KRAS-mutant and 25% of wild-type CRC patients. Further, whether in KRAS-mutant or wild-type patients, elevated FUBP1 was positively correlated with CRC lymph node metastasis and clinical stage, and negatively associated with overall survival. Overexpression of FUBP1 significantly enhanced CRC cell migration, invasion, tumor sphere formation, and CD133 and ALDH1 expression in vitro, and tumorigenicity in vivo. Mechanistically, FUBP1 promoted the initiation of CSCs by activating Wnt/ß-catenin signaling via directly binding to the promoter of DVL1, a potent activator of ß-catenin. Knockdown of DVL1 significantly inhibited the transformation to stem cells in, as well as the tumorigenicity of, CRC. Activation of Wnt/ß-catenin signaling by DVL1 increased pluripotent transcription factors, including c-Myc, NANOG, and SOX2. Moreover, FUBP1 was upregulated at the post-transcriptional level. Elevated FUBP1 levels in KRAS wild-type CRC patients is due to the decrease in Smurf2, which promotes ubiquitin-mediated degradation of FUBP1. In contrast, FUBP1 was upregulated in KRAS-mutant patients through both inhibition of caspase 3-dependent cleavage and decreased Smurf2. Our results demonstrate, for the first time, that FUBP1 is an oncogene, initiating the development of CSCs, as well as a new powerful endogenous Wnt-signaling agonist that could provide an important prognostic factor and therapeutic target for metastasis in both KRAS-mutant and wild-type CRC.

PEDF inhibits lymphatic metastasis of nasopharyngeal carcinoma as a new lymphangiogenesis inhibitor.

Nasopharyngeal carcinoma (NPC) is one of the most malignant tumors in southern China and Asia, and lymph node metastasis is an important cause for treatment failure. Lymphangiogenesis is a crucial step in lymphatic metastasis of NPC, while little is known about lymphangiogenesis in NPC. Similar to angiogenesis, lymphangitic neovascularization is a process of balance between pro-lymphangiogenesis and anti-lymphangiogenesis factors, but there are few studies on endogenous lymphangiogenesis inhibitors. Pigment epithelium-derived factor (PEDF) is a well-known effective endogenous angiogenesis inhibitor. However, the relationship between PEDF and lymphangiogenesis remains unknown. Our present study reveals that PEDF is lowly expressed in human NPC tissues with poor prognosis and is negatively correlated with lymphatic vessel density (LVD). Consistently, PEDF inhibits lymphangiogenesis and lymphatic metastasis of NPC in vivo experiments. Mechanistically, PEDF inhibits the proliferation, migration, and tube formation of lymphatic endothelial cells and promotes cell apoptosis. On the other hand, PEDF reduces the expression and secretion of vascular endothelial growth factor C (VEGF-C) of NPC cells through the nuclear factor-κB (NF-κB) signaling pathway. Our findings indicate that PEDF plays a vital role in lymphatic metastasis by targeting both lymphatic endothelial cells and NPC cells, and PEDF may represent a novel therapeutic target for NPC.

Metformin selectively inhibits metastatic colorectal cancer with the KRAS mutation by intracellular accumulation through silencing MATE1.

Metastatic colorectal cancer (mCRC) patients have poor overall survival despite using irinotecan- or oxaliplatin-based chemotherapy combined with anti-EGFR (epidermal growth factor receptor) drugs, especially those with the oncogene mutation of KRAS Metformin has been reported as a potentially novel antitumor agent in many experiments, but its therapeutic activity is discrepant and controversial so far. Inspiringly, the median survival time for KRAS-mutation mCRC patients with diabetes on metformin is 37.8 mo longer than those treated with other hypoglycemic drugs in combination with standard systemic therapy. In contrast, metformin could not improve the survival of mCRC patients with wild-type KRAS Interestingly, metformin is preferentially accumulated in KRAS-mutation mCRC cells, but not wild-type ones, in both primary cell cultures and patient-derived xenografts, which is in agreement with its tremendous effect in KRAS-mutation mCRC. Mechanistically, the mutated KRAS oncoprotein hypermethylates and silences the expression of multidrug and toxic compound extrusion 1 (MATE1), a specific pump that expels metformin from the tumor cells by up-regulating DNA methyltransferase 1 (DNMT1). Our findings provide evidence that KRAS-mutation mCRC patients benefit from metformin treatment and targeting MATE1 may provide a strategy to improve the anticancer response of metformin.

Elevated pigment epithelium-derived factor induces diabetic erectile dysfunction via interruption of the Akt/Hsp90ß/eNOS complex.

AIMS/HYPOTHESIS: Diabetes mellitus erectile dysfunction (DMED) is a common complication of diabetes. The level of pigment epithelium-derived factor (PEDF) is significantly upregulated in the serum of individuals with obesity and diabetes. However, whether elevated PEDF levels contribute to DMED remains unknown. This study aimed to investigate the pathogenic role of PEDF and its related mechanism in DMED. METHODS: We enrolled 65 men, of whom 20 were nondiabetic control participants, 21 participants with diabetes but without erectile dysfunction, and 24 with DMED. The International Index of Erectile Function (IIEF-5) questionnaire was administered to evaluate erectile function. Plasma PEDF in diabetic participants and streptozotocin (STZ)-induced diabetic animals was detected by ELISA. Erectile function was evaluated by measuring the intracavernous pressure (ICP) and the ICP/mean arterial pressure (MAP) ratio in STZ-induced diabetic rats treated with PEDF-neutralising antibody (PEDF-Ab), db/db mice treated with PEDF-Ab, and Pedf knockout mice with STZ-induced diabetes. The overexpression of PEDF was implemented by intraperitoneal injection of recombinant PEDF and intracavernous injection of PEDF-expressing adenovirus. A mechanistic study was performed by immunofluorescence staining, bimolecular fluorescence complementation (BiFC), immunoprecipitation and western blotting. RESULTS: We found that the plasma level of PEDF was significantly higher in participants with DMED compared with diabetic counterparts without erectile dysfunction and nondiabetic controls. Interestingly, PEDF levels were negatively correlated with plasma nitrite/nitrate levels and erectile function in DMED patients and STZ-induced diabetic rats. Furthermore, overexpression of PEDF significantly suppressed ICP and endothelial nitric oxide synthase (eNOS) phosphorylation in control rats. In contrast, the PEDF-Ab and Pedf knockout ameliorated ICP and eNOS phosphorylation in diabetic rats and mice. Mechanistically, PEDF promoted the membrane translocation of Hsp90ß and directly bound to the amino acid residues 341-724 of Hsp90ß on the endothelial cell surface, subsequently blocking intracellular Hsp90ß/Akt/eNOS complex formation and downregulating eNOS phosphorylation. CONCLUSIONS/INTERPRETATION: These results indicate that elevated PEDF levels contribute to impaired erectile function by suppressing Hsp90ß-mediated eNOS phosphorylation and that PEDF may represent a novel therapeutic target for diabetic erectile dysfunction. Graphical abstract.