Tumor necrosis factor receptor 2 promotes endothelial cell-mediated suppression of CD8+ T cells through tuning glycolysis in chemoresistance of breast cancer.

BACKGROUND: T cells play a pivotal role in chemotherapy-triggered anti-tumor effects. Emerging evidence underscores the link between impaired anti-tumor immune responses and resistance to paclitaxel therapy in triple-negative breast cancer (TNBC). Tumor-related endothelial cells (ECs) have potential immunoregulatory activity. However, how ECs regulate T cell activity during TNBC chemotherapy remains poorly understood. METHODS: Single-cell analysis of ECs in patients with TNBC receiving paclitaxel therapy was performed using an accessible single-cell RNA sequencing (scRNA-seq) dataset to identify key EC subtypes and their immune characteristics. An integrated analysis of a tumor-bearing mouse model, immunofluorescence, and a spatial transcriptome dataset revealed the spatial relationship between ECs, especially Tumor necrosis factor receptor (TNFR) 2+ ECs, and CD8+ T cells. RNA sequencing, CD8+ T cell proliferation assays, flow cytometry, and bioinformatic analyses were performed to explore the immunosuppressive function of TNFR2 in ECs. The downstream metabolic mechanism of TNFR2 was further investigated using RNA sequencing, cellular glycolysis assays, and western blotting. RESULTS: In this study, we identified an immunoregulatory EC subtype, characterized by enhanced TNFR2 expression in non-responders. By a mouse model of TNBC, we revealed a dynamic reduction in the proportion of the CD8+ T cell-contacting tumor vessels that could co-localize spatially with CD8+ T cells during chemotherapy and an increased expression of TNFR2 by ECs. TNFR2 suppresses glycolytic activity in ECs by activating NF-κB signaling in vitro. Tuning endothelial glycolysis enhances programmed death-ligand (PD-L) 1-dependent inhibitory capacity, thereby inducing CD8+ T cell suppression. In addition, TNFR2+ ECs showed a greater spatial affinity for exhausted CD8+ T cells than for non-exhausted CD8+ T cells. TNFR2 blockade restores impaired anti-tumor immunity in vivo, leading to the loss of PD-L1 expression by ECs and enhancement of CD8+ T cell infiltration into the tumors. CONCLUSIONS: These findings reveal the suppression of CD8+ T cells by ECs in chemoresistance and indicate the critical role of TNFR2 in driving the immunosuppressive capacity of ECs via tuning glycolysis. Targeting endothelial TNFR2 may serve as a potent strategy for treating TNBC with paclitaxel.

Deep Learning Bridged Bioactivity, Structure, and GC-HRMS-Readable Evidence to Decipher Nontarget Toxicants in Sediments.

Identifying causative toxicants in mixtures is critical, but this task is challenging when mixtures contain multiple chemical classes. Effect-based methods are used to complement chemical analyses to identify toxicants, yet conventional bioassays typically rely on an apical and/or single endpoint, providing limited diagnostic potential to guide chemical prioritization. We proposed an event-driven taxonomy framework for mixture risk assessment that relied on high-throughput screening bioassays and toxicant identification integrated by deep learning. In this work, the framework was evaluated using chemical mixtures in sediments eliciting aryl-hydrocarbon receptor activation and oxidative stress response. Mixture prediction using target analysis explained <10% of observed sediment bioactivity. To identify additional contaminants, two deep learning models were developed to predict fingerprints of a pool of bioactive substances (event driver fingerprint, EDFP) and convert these candidates to MS-readable information (event driver ion, EDION) for nontarget analysis. Two libraries with 121 and 118 fingerprints were established, and 247 bioactive compounds were identified at confidence level 2 or 3 in sediment extract using GC-qToF-MS. Among them, 12 toxicants were analytically confirmed using reference standards. Collectively, we present a "bioactivity-signature-toxicant" strategy to deconvolute mixtures and to connect patchy data sets and guide nontarget analysis for diverse chemicals that elicit the same bioactivity.

Doxorubicin-induced cardiotoxicity involves IFNγ-mediated metabolic reprogramming in cardiomyocytes.

Immune responses contribute to a large extent to heart diseases. However, it is still not clear how the key inflammatory mediator interferon-γ (IFNγ) plays a role in doxorubicin (DOX)-induced cardiomyopathy. We report here that DOX-induced heart dysfunction involves IFNγ signaling in mice. The IFNγ receptor was found to be highly expressed on cardiomyocytes, and its downstream signaling was activated in heart tissues upon DOX treatment. In vitro, IFNγ strongly aggravated the injury of cardiomyocytes exposed to DOX. Although not affecting DOX-induced cell death, IFNγ disrupted mitochondrial respiration and fatty acid oxidation in DOX-exposed cardiomyocytes. IFNγ extended the suppression of the AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) axis by DOX to a p38-dependent branch. Activation of AMPK or inhibition of p38 inhibited the enhancing effect of IFNγ on the DOX-induced cardiotoxicity and prolonged the survival time in DOX-treated mice. Taken together, our results indicate that reprogramming of cardiac metabolism by IFNγ represents a previously unidentified key step for DOX-induced cardiomyopathy. This unavoidable impact of IFNγ on cardiomyocyte metabolism during chemotherapy redirects our attention to the balance between beneficial immunosurveillance of cancer cells and unwanted toxic side-effects. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

IFNγ inhibits fibroblast-leading tumor cell invasion through downregulating N-cadherin.

Tumor metastasis accounts for most tumor-associated mortality and is closely related with stromal fibroblasts in the tumor microenvironment. It was reported that fibroblasts promoted tumor metastasis through directly leading tumor cell invasion; however, inflammatory microenvironment in the growing tumor may influence the outcome. Here, we found that the cytokine IFNγ, a key immune mediator secreted by T cells, could alter mouse lung tumor associated fibroblast-leading LLC tumor cell invasion in Matrigel. The motility of fibroblasts and adhesion with tumor cells were dramatically impaired upon IFNγ stimulation. We further found that IFNγ reduced the expression of N-cadherin on the surface of fibroblasts through upregulating SMAD7 and suppressing the downstream SMAD2 phosphorylation. N-cadherin was essential for fibroblast motility and adhesions with tumor cells. Moreover, fibroblasts could promote tumor progression and the deficiency of IFNγR signaling in fibroblasts reduced liver metastasis of LLC tumor in vivo. Collectively, our results demonstrate that IFNγ inhibits fibroblast-leading tumor cell invasion by inhibiting the motility of fibroblasts and their adhesion with tumor cells. The findings indicate that inflammatory cytokines in the tumor microenvironment may regulate the fibroblast-associated tumor metastasis.

IFN-γ-responsiveness of lymphatic endothelial cells inhibits melanoma lymphatic dissemination via AMPK-mediated metabolic control.

The integrity of the lymphatic system is critical for preventing the dissemination of tumor cells, such as melanoma, to distant parts of the body. IFN-γ is well studied as a negative regulator for lymphangiogenesis, which is strongly associated with cancer metastasis. However, the exact mechanisms underlying this process remain unclear. In the present study, we investigated whether IFN-γ signaling in lymphatic endothelial cells (LECs) affects tumor cell dissemination by regulating the barrier function of tumor-associated lymphatic vessels. Using LEC-specific IFN-γ receptor (IFN-γR) knockout mice, we found that the loss of IFN-γR in LECs increased the dissemination of melanoma cells into the draining lymph nodes. Notably, IFN-γ signaling in LECs inhibited trans-lymphatic endothelial cell migration of melanoma cells, indicating its regulation of lymphatic barrier function. Further investigations revealed that IFN-γ upregulated the expression of the tight junction protein Claudin-3 in LECs, while knockdown of Claudin-3 in LECs abolished IFN-γ-induced inhibition of trans-lymphatic endothelial migration activity. Mechanistically, IFN-γ inhibits AMPK signaling activation, which is involved in the regulation of fatty acid metabolism. Modulating fatty acid metabolism and AMPK activation in LECs also affected the lymphatic dissemination of melanoma cells, further confirming that this process is involved in IFN-γ-induced regulation of lymphatic barrier function. These results provide novel insights into how IFN-γ modulates tight junctions in LECs, inhibiting the dissemination of melanoma cells via the lymphatic vessels.

Chemotherapy-induced PTEN-L secretion promotes the selection of PTEN-deficient tumor cells.

BACKGROUND: PTEN loss has been identified in various tumor types and is linked to unfavorable clinical outcomes. In addition to PTEN mutation, multiple mechanisms contribute to PTEN loss during tumor development. However, the natural selection process of PTEN-deficient tumor cells remains unclear. Here, we aimed at further elucidating the role of PTEN-L in tumor progression. METHODS: PTEN knockout cell lines were generated using CRISPR/Cas9 technology. Ni-NTA affinity column chromatography was employed for PTEN-L purification. Tumor cell metastasis was evaluated in murine models and observed using the IVIS Spectrum Imaging System. RNA-sequencing, western blotting, PCR, flow cytometry, and cell proliferation assays were employed to investigate tumor cell dormancy and related mechanisms. RESULTS: The chemotherapeutic drugs, cisplatin, paclitaxel, and doxorubicin, induced tumor cells to secrete PTEN-long (PTEN-L), which shields PTEN-deficient tumor cells from chemotherapy-induced apoptosis better than it shields PTEN-intact cells. Further investigation revealed that PTEN-L treatment induced dormancy in PTEN-null tumor cells, characterized by an increase in p16 and p27 levels, cell-cycle arrest, reduced cell proliferation, and enhanced DNA repair. Furthermore, PTEN-L treatment selectively promoted the accumulation and growth of PTEN-null tumor cells in the lungs of C57BL/6J mice, while evading immune surveillance. Mechanistically, PTEN-L induced dormancy in PTEN-null tumor cells by activating the p38 signaling pathway. Addition of a p38 inhibitor effectively reversed dormancy and growth of PTEN-deficient tumor cells in the lungs. We also demonstrated that PTEN expression played a pivotal role in determining the outcome of PTEN-L-mediated antitumor therapy. CONCLUSIONS: In summary, PTEN-L was identified as a potent inducer of dormancy in PTEN-deficient tumor cells, which increased their efficient selection within the tumor microenvironment.

A polymeric nanoplatform enhances the cGAS-STING pathway in macrophages to potentiate phagocytosis for cancer immunotherapy.

Immunosuppressive tumor-associated macrophages (TAMs) account for a high proportion of the tumor tissue and significantly impede immunoefficacy. Furthermore, the signal regulatory protein α (SIRPα) expressed in TAMs adversely correlates with macrophage activation and phagocytosis, resulting in immunosurveillance escape. To address these difficulties, a mannose-modified, pH-responsive nanoplatform with resiquimod (R848) and 2', 3'-cyclic GMP-AMP (cGAMP) co-encapsulation (named M-PNP@R@C) is designed to polarize TAMs and lower SIRPα expression. The co-delivery of R848 and cGAMP synergistically facilitates the polarization of TAMs from the anti-inflammatory M2 phenotype into the pro-inflammatory M1 phenotype, thereby enhancing antitumor immunotherapy. Remarkably, activation of the cGAMP-mediated stimulator of interferon genes (STING) in TAMs significantly downregulates the expression of SIRPα, which synergizes with the cluster of differentiation 47 (CD47) antibody for the dual blockade of the CD47-SIRPα axis. Further analysis of single-cell RNA sequencing indicates that STING activation downregulates SIRPα by regulating intracellular fatty acid oxidation metabolism. In vivo studies indicate that M-PNP@R@C significantly inhibits tumor growth with a potent antitumor immune response in melanoma graft tumor models. After synergy with anti-CD47, the double blockade strategies of the SIRPα/CD47 axis result in a notable inhibition of lung metastasis. A prolonged survival rate is observed after combination treatment with CD47 and programmed death ligand-1 antibodies for the triple immune checkpoint blockade. In summary, our study provides original insights into the potential role of the STING pathway in macrophage-based immunotherapy, thus offering a potential combinatorial strategy for cancer therapy.

Hyperexpression of tumor necrosis factor receptor 2 inhibits differentiation of myeloid-derived suppressor cells by instigating apolarity during ageing.

During the ageing process, TNF-α can promote the expansion of myeloid-derived suppressor cells (MDSCs). However, it remains unclear which receptor(s) of TNF-α are involved in and how they modulate this process. Here, we report that TNFR2 hyperexpression induced by either TNF-α or IL-6, two proinflammatory factors of senescence-associated secretory phenotype (SASP), causes cellular apolarity and differentiation inhibition in aged MDSCs. Ex vivo overexpression of TNFR2 in young MDSCs inhibited their polarity and differentiation, whereas in vivo depletion of Tnfr2 in aged MDSCs promotes their differentiation. Consequently, the age-dependent increase of TNFR2 versus unaltered TNFR1 expression in aged MDSCs significantly shifts the balance of TNF-α signaling toward the TNFR2-JNK axis, which accounts for JNK-induced impairment of cell polarity and differentiation failure of aged MDSCs. Consistently, inhibiting JNK attenuates apolarity and partially restores the differentiation capacity of aged MDSCs, suggesting that upregulated TNFR2/JNK signaling is a key factor limiting MDSC differentiation during organismal ageing. Therefore, abnormal hyperexpression of TNFR2 represents a general mechanism by which extrinsic SASP signals disrupt intrinsic cell polarity behavior, thereby arresting mature differentiation of MDSCs with ageing, suggesting that TNFR2 could be a potential therapeutic target for intervention of ageing through rejuvenation of aged MDSCs.

IFNγ blockade in capillary leak site improves tumour chemotherapy by inhibiting lactate-induced endocytosis of vascular endothelial-cadherins.

IFNγ has long been recognised as a key mediator of tumour immunity and angiostasis. However, IFNγ modulation for cancer therapy is still unsuccessful due to its complex effects on various host cells. In this study, we found that treatment of Lewis lung carcinoma transplants with cisplatin often caused IFNγ-dependent tumour vascular damage. IFNγ induced endothelial glycolysis and lactate production, leading to enhanced endocytosis of vascular endothelial (VE)-cadherin and vessel leakage. We have also developed anti-IFNγ nanoparticles coated with a clot-binding peptide CREKA (CREKA-lipo-anti-IFNγ), which targets the fibrin-fibronectin complex that appears in the leaky site of damaged tumour blood vessels. Blocking IFNγ activity in the leakage site of capillaries using nanoparticles rescued VE-cadherin distribution on the endothelial cellular surface, promoted blood vessel integrity, and improved drug delivery. In conclusion, IFNγ blockade in capillary leak site protected tumour blood vessels from lactate-dependent VE-cadherin loss and enhanced drug delivery during chemotherapy, which provides a basis for tissue-specific IFNγ blockade for tumour therapy.

Transgelin promotes lung cancer progression via activation of cancer-associated fibroblasts with enhanced IL-6 release.

Cancer-associated fibroblasts (CAFs), the principal constituent of the heterogenous tumor microenvironment, have been shown to promote tumor progression; however, the underlying mechanism is still less clear. Here, we find that transgelin (TAGLN) protein levels increased in primary CAFs isolated from human lung cancer, compared with those in paired normal fibroblasts. Tumor microarrays (TMAs) revealed that increased stromal TAGLN levels correlates with more lymphatic metastasis of tumor cells. In a subcutaneous tumor transplantation model, overexpression of Tagln in fibroblasts also increased tumor cell spread in mice. Further experiments show that Tagln overexpression promoted fibroblast activation and mobility in vitro. And TAGLN facilitates p-p65 entry into the nucleus, thereby activating the NF-κB signaling pathway in fibroblasts. Activated fibroblasts promote lung cancer progression via enhancing the release of pro-inflammatory cytokines, especially interleukine-6 (IL-6). Our study revealed that the high levels of stromal TAGLN is a predictive risk factor for patients with lung cancer. Targeting stromal TAGLN may present an alternative therapeutic strategy against lung cancer progression.

Ablation of Gap Junction Protein Improves the Efficiency of Nanozyme-Mediated Catalytic/Starvation/Mild-Temperature Photothermal Therapy.

Reactive oxygen species (ROS)-mediated tumor catalytic therapy is typically hindered by gap junction proteins that form cell-to-cell channels to remove cytotoxic ROS, thereby protecting tumor cells from oxidative damage. In this work, a multifunctional nanozyme, FePGOGA, is designed and prepared by Fe(III)-mediated oxidative polymerization (FeP), followed by glucose oxidase (GOx) and GAP19 peptides co-loading through electrostatic and π-π interactions. The FePGOGA nanozyme exhibits excellent cascade peroxidase- and glutathione-oxidase-like activities that efficiently catalyze hydrogen peroxide conversion to hydroxyl radicals and convert reduced glutathione to oxidized glutathione disulfide. The loaded GOx starves the tumors and aggravates tumor oxidative stress through glucose decomposition, while GAP19 peptides block the hemichannels by inducing degradation of Cx43, thus increasing the accumulation of intracellular ROS, and decreasing the transport of intracellular glucose. Furthermore, the ROS reacts with primary amines of heat shock proteins to destroy their structure and function, enabling tumor photothermal therapy at the widely sought-after mild temperature (mildPTT, ≤45 °C). In vivo experiments demonstrate the significant antitumor effectof FePGOGA on cal27 xenograft tumors under near-infrared light irradiation. This study demonstrates the successful ablation of gap junction proteins to overcome resistance to ROS-mediated therapy, providing a regulator to suppress tumor self-preservation during tumor starvation, catalytic therapy, and mildPTT.

Spleen-selective co-delivery of mRNA and TLR4 agonist-loaded LNPs for synergistic immunostimulation and Th1 immune responses.

Spleen is an ideal site for initiating and amplifying antigen-specific immune response. However, spleen-selective antigen delivery has limited tumor therapeutic efficacy owing to an inadequate cytotoxic T-cell immune response. In this study, we designed a spleen-selective mRNA vaccine that delivered unmodified mRNA and Toll-like Receptor (TLR) agonists to the spleen after systemic administration, resulting in a sufficient and persistent antitumor cellular immune response with potent tumor immunotherapeutic efficacy. To establish potent tumor vaccines (sLNPs-OVA/MPLA), we co-loaded stearic acid doped lipid nanoparticles with ovalbumin (OVA)-coding mRNA and TLR4 agonists (MPLA). We found that sLNPs-OVA/MPLA facilitated tissue-specific mRNA expression in the spleen after intravenous injection and elicited enhanced adjuvant activity with Th1 immune responses by activating multiple TLRs. In a prophylactic mouse model, sLNPs-OVA/MPLA induced a potent antigen-specific cytotoxic T cell immune response and ultimately prevented the growth of EG.7-OVA tumors with persistent immune memory protection. In addition, sLNPs-OVA/MPLA effectively delayed the tumor growth of EG.7-OVA subcutaneously transplanted lymphoma and lung metastasis formation of B16F10-OVA intravenously injected melanoma. This study showed that the co-delivery of mRNA antigens and appropriate TLR agonists could significantly improve the antitumor immunotherapeutic efficacy of spleen-targeted mRNA vaccines via synergistic immunostimulation and Th1 immune responses.

Stearoyl-CoA Desaturase-1 dependent lipid droplets accumulation in cancer-associated fibroblasts facilitates the progression of lung cancer.

Rationale: Cancer-associated fibroblasts (CAFs) are the main components in the tumor microenvironment (TME) and facilitate lung cancer progression. Studies have reported that metabolic reprogramming can regulate the function of CAFs, especially abnormal lipid metabolism. Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids and have a crucial role in lipid metabolism. However, little is known about the synthesis and functions of LDs in lung CAFs. Methods: TetO-EGFRL858R; CCSP-rtTA transgenic mouse model was used to establish a spontaneous pulmonary tumor model and investigate the accumulation of LDs in CAFs. The effect of LDs accumulation on the phenotype change of fibroblasts was estimated in vitro using mouse fibroblast cell lines. RNA sequencing, Western blotting, RT-PCR, and DNA-pull down were performed to determine the mechanism of LDs synthesis in fibroblasts. Results: We found that LDs were enriched in lung CAFs and induced the pro-tumoral phenotype of CAFs with increased expression of α-smooth muscle actin (α-SMA) and Collagen alpha-2 (I) chain (COL1A2). As the main regulator, hypoxia-inducible factor-1α (HIF-1α) was highly expressed in activated fibroblasts and increased the content of LDs. RNA-sequencing results showed that Stearoyl-CoA Desaturase1 (SCD1) was a downstream gene of HIF-1α, which upregulated the number of LDs in fibroblasts. Importantly, SCD1 inhibition reduced the growth of lung tumors, which was correlated with LDs decrease in CAFs. Analysis of human lung adenocarcinoma tissue chip revealed that CAFs with a high level of SCD1 were positively correlated with the expression of HIF-1α and poor survival in lung cancer patients. Conclusions: The HIF-1α/SCD1 axis regulates the accumulation of LDs in CAFs, which might represent a novel target for lung cancer therapy.

Claudin-12 Deficiency Inhibits Tumor Growth by Impairing Transendothelial Migration of Myeloid-Derived Suppressor Cells.

Migration of myeloid-derived suppressor cells (MDSC) out of the circulation, across vascular walls, and into tumor is crucial for their immunosuppressive activity. A deeper understanding of critical junctional molecules and the regulatory mechanisms that mediate the extravasation of MDSCs could identify approaches to overcome cancer immunosuppression. In this study, we used mice deficient in tight junction protein Claudin-12 (Cldn12) compared with wild-type mice and found that loss of host Cldn12 inhibited the growth of transplanted tumors, reduced intratumoral accumulation of MDSCs, increased antitumor immune responses, and decreased tumor vascular density. Further studies revealed that Cldn12 expression on the cell surface of both MDSCs and endothelial cells (EC) is required for MDSCs transit across tumor vascular ECs. Importantly, expression of Cldn12 in MDSCs was modulated by GM-CSF in an AKT-dependent manner. Therefore, our results indicate that Cldn12 could serve as a promising target for restoring the antitumor response by interfering with MDSCs transendothelial migration. SIGNIFICANCE: Claudin-12-mediated homotypic interactions are critical for migration of myeloid-derived suppressor cells across vascular walls into tumor tissue, providing a potential therapeutic approach to overcome cancer immunosuppression.

Paclitaxel treatment enhances lymphatic metastasis of B16F10 melanoma cells via CCL21/CCR7 axis.

Chemotherapeutic drugs have been successfully used to treat several cancers, including melanoma. However, metastasis occasionally occurs after chemotherapy. Here, we reported that paclitaxel (PTX) treatment for B16F10 tumour in mice led to an enhanced lymphatic metastasis of the melanoma cells, although a significant inhibition of tumour growth at the injection site was observed. Further study demonstrated that PTX upregulated the expression of C-C chemokine receptor type 7 (CCR7) in B16F10 cells, enhancing their migration through the activation of JNK and p38 signalling pathways. Loss of CCR7 or blockade of C-C motif chemokine ligand 21 (CCL21)/CCR7 axis abolished the pro-migration effect of PTX on B16F10 melanoma cells. Importantly, combination of PTX and CCR7 mAb could simultaneously delay the tumour growth and reduce the lymphatic metastasis in B16F10 melanoma. The blockade of CCL21/CCR7 axis may collectively serve as a strategy for lymphatic metastasis in some melanoma after chemotherapy.

ZIP1+ fibroblasts protect lung cancer against chemotherapy via connexin-43 mediated intercellular Zn2+ transfer.

Tumour-stroma cell interactions impact cancer progression and therapy responses. Intercellular communication between fibroblasts and cancer cells using various soluble mediators has often been reported. In this study, we find that a zinc-transporter (ZIP1) positive tumour-associated fibroblast subset is enriched after chemotherapy and directly interconnects lung cancer cells with gap junctions. Using single-cell RNA sequencing, we identify several fibroblast subpopulations, among which Zip1+ fibroblasts are highly enriched in mouse lung tumours after doxorubicin treatment. ZIP1 expression on fibroblasts enhances gap junction formation in cancer cells by upregulating connexin-43. Acting as a Zn2+ reservoir, ZIP1+ fibroblasts absorb and transfer Zn2+ to cancer cells, leading to ABCB1-mediated chemoresistance. Clinically, ZIP1high stromal fibroblasts are also associated with chemoresistance in human lung cancers. Taken together, our results reveal a mechanism by which fibroblasts interact directly with tumour cells via gap junctions and contribute to chemoresistance in lung cancer.

Cinnamaldehyde induces endogenous apoptosis of the prostate cancer-associated fibroblasts via interfering the Glutathione-associated mitochondria function.

Cinnamaldehyde (CA) is an essential component of cinnamon that has been shown to exhibit anti-tumor effects through growth inhibition and induction of apoptosis in cancer cells. We have previously shown that CA could interfere with myeloid-derived suppressor cells (MDSCs), leading to cancer growth inhibition. In addition, recent studies have demonstrated that cancer-associated fibroblasts (CAFs) promote cancer development in different ways. However, the effect of CA in CAFs has not been studied. In this study, we investigated the effect and mechanism of action of CA in prostate CAFs. We found that CA induced cell cycle arrest and apoptosis in prostate CAFs via the intrinsic pathway. This was due to the decrease in mitochondrial membrane potential (∆Mψ), increased level of intracellular reactive oxygen species (ROS), and calcium ion (Ca2+). In addition, protein expression analysis showed an increase in the expression levels of cytochrome c, bax, cleaved caspase 3 and cleaved PARP, and a decrease in the expression levels of Bcl-2, caspase 9, PARP, and DEF-45. Interestingly, reduced glutathione (GSH) rescued CAFs from CA-induced cell apoptosis, demonstrating that generation of ROS is critical for this effect. From this study, we see that CA has the ability to inhibit growth of CAFs and is therefore a potential cancer therapeutic target.

Aspirin, a Potential GLUT1 Inhibitor in a Vascular Endothelial Cell Line.

Recent epidemiological and preclinical studies have revealed that aspirin possesses antitumor properties; one of the mechanisms results from inhibition of angiogenesis. However, the underlying mechanisms of such action remain to be elucidated, in particular, the effect of aspirin on glucose metabolism of vascular endothelial cells (ECs) has not yet been reported. Herein, we demonstrate that glucose transporter 1 (GLUT1), a main glucose transporter in ECs, can be down-regulated by aspirin. Exposure to 4-mM aspirin significantly decreased GLUT1 at the mRNA and protein level, resulting in impaired glucose uptake capacity in vascular ECs. In addition, we also showed that exposure to 4-mM aspirin led to an inhibition of intracellular ATP and lactate synthesis in vascular ECs, and a down-regulation of the phosphorylation level of NF-κB p65 was observed. Taken together, these findings indicate 4-mM aspirin inhibits glucose uptake and glucose metabolism of vascular ECs through down-regulating GLUT1 expression and suggest that GLUT1 has potential to be a target for aspirin in vascular ECs.

IL-17A-stimulated endothelial fatty acid ß-oxidation promotes tumor angiogenesis.

AIMS: Tumor growth is an angiogenesis-dependent process that requires sustained new vessel growth. Interleukin-17 (IL-17A) is a key cytokine that modulates tumor progression. However, whether IL-17A affects the metabolism of endothelial cells is unknown. MAIN METHODS: A xenograft model was established by implanting H460 (human lung cancer cell line) cells transfected with IL-17A-expressing or control vector. The effects of IL-17A on sprouting and tube formation of human umbilical vein endothelial cells (HUVECs) were measured. After treatment with IL-17A, the proliferation and migration of HUVECs were examined. Liquid chromatography-mass spectrometry (LC-MS) and Seahorse were used to detect the effects of IL-17A on mitochondrial respiration and fatty acid ß-oxidation (FAO) in HUVECs. Western blotting was used to examine signaling pathways. KEY FINDINGS: Herein, we found that IL-17A promoted H460 tumor growth and angiogenesis in vivo and in vitro. Moreover, IL-17A stimulated angiogenesis by enhancing FAO, increasing mitochondrial respiration of endothelial cells. The AMP-activated protein kinase (AMPK) signaling pathway was activated to promote FAO. Finally, IL-17A-induced angiogenesis was blocked when FAO was inhibited using etomoxir. SIGNIFICANCE: In summary, these results indicate that IL-17A stimulates angiogenesis by promoting FAO. Thus, our study might provide a new therapeutic target for angiogenic vascular disorders.