mTORC2 mediates CXCL12-induced angiogenesis

Enriched environment enhances angiogenesis in ischemic stroke through SDF-1/CXCR4/AKT/mTOR pathway

Environmental-gene interactions significantly influence various bodily functions. Enriched environment (EE), a non-pharmacological treatment method, enhances angiogenesis in ischemic stroke (IS). However, underlying the role of EE in angiogenesis in aged mice post-IS remain unclear. This study aimed to determine the potential mechanism by which EE mediates angiogenesis in 12-month-old IS mice and oxygen-glucose deprivation/reperfusion (OGD/R)-induced bEnd.3 cells. In vivo, EE treatment alleviated the neurological deficits, enhanced angiogenesis, upregulated SDF-1, VEGFA, and the AKT/mTOR pathway. In addition, exogenous SDF-1 treatment had a protective effect similar to that of EE treatment in aged mice with IS. However, SDF-1 neutralizing antibody, AMD3100 (CXCR4 inhibitor), ARQ092 (AKT inhibitor), and rapamycin (mTOR inhibitor) treatment blocked the neuroprotective effect of EE treatment and inhibited angiogenesis in IS mice. In vitro, exogenous SDF-1 promoted migration of OGD/R-induced bEnd.3 cells and activated the AKT/mTOR pathway. AMD3100, ARQ092, and rapamycin inhibited SDF-1-induced cell migration. Collectively, these findings demonstrate that EE enhances angiogenesis and improves the IS outcomes through SDF-1/CXCR4/AKT/mTOR pathway.

Pathological progression of osteoarthritis: a perspective on subchondral bone

Osteoarthritis (OA) is a degenerative bone disease associated with aging. The rising global aging population has led to a surge in OA cases, thereby imposing a significant socioeconomic burden. Researchers have been keenly investigating the mechanisms underlying OA. Previous studies have suggested that the disease starts with synovial inflammation and hyperplasia, advancing toward cartilage degradation. Ultimately, subchondral-bone collapse, sclerosis, and osteophyte formation occur. This progression is deemed as "top to bottom." However, recent research is challenging this perspective by indicating that initial changes occur in subchondral bone, precipitating cartilage breakdown. In this review, we elucidate the epidemiology of OA and present an in-depth overview of the subchondral bone's physiological state, functions, and the varied pathological shifts during OA progression. We also introduce the role of multifunctional signal pathways (including osteoprotegerin (OPG)/receptor activator of nuclear factor-kappa B ligand (RANKL)/receptor activator of nuclear factor-kappa B (RANK), and chemokine (CXC motif) ligand 12 (CXCL12)/CXC motif chemokine receptor 4 (CXCR4)) in the pathology of subchondral bone and their role in the "bottom-up" progression of OA. Using vivid pattern maps and clinical images, this review highlights the crucial role of subchondral bone in driving OA progression, illuminating its interplay with the condition.

DNA Damage-driven Inflammatory Cytokines: Reprogramming of Tumor Immune Microenvironment and Application of Oncotherapy

DNA damage occurs across tumorigenesis and tumor development. Tumor intrinsic DNA damage can not only increase the risk of mutations responsible for tumor generation but also initiate a cellular stress response to orchestrate the tumor immune microenvironment (TIME) and dominate tumor progression. Accumulating evidence documents that multiple signaling pathways, including cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) and ataxia telangiectasia-mutated protein/ataxia telangiectasia and Rad3-related protein (ATM/ATR), are activated downstream of DNA damage and they are associated with the secretion of diverse cytokines. These cytokines possess multifaced functions in the anti-tumor immune response. Thus, it is necessary to deeply interpret the complex TIME reshaped by damaged DNA and tumor-derived cytokines, critical for the development of effective tumor therapies. This manuscript comprehensively reviews the relationship between the DNA damage response and related cytokines in tumors and depicts the dual immunoregulatory roles of these cytokines. We also summarize clinical trials targeting signaling pathways and cytokines associated with DNA damage and provide future perspectives on emerging technologies.

Targeting tumor-stromal interactions in triple-negative breast cancer using a human vascularized micro-tumor model

Triple-negative breast cancer (TNBC) is highly aggressive with limited available treatments. Stromal cells in the tumor microenvironment (TME) are crucial in TNBC progression; however, understanding the molecular basis of stromal cell activation and tumor-stromal crosstalk in TNBC is limited. To investigate therapeutic targets in the TNBC stromal niche, we used an advanced human in vitro microphysiological system called the vascularized micro-tumor (VMT). Using single-cell RNA sequencing, we revealed that normal breast tissue stromal cells activate neoplastic signaling pathways in the TNBC TME. By comparing interactions in VMTs with clinical data, we identified therapeutic targets at the tumor-stromal interface with potential clinical significance. Combining treatments targeting Tie2 signaling with paclitaxel resulted in vessel normalization and increased efficacy of paclitaxel in the TNBC VMT. Dual inhibition of HER3 and Akt also showed efficacy against TNBC. These data demonstrate the potential of inducing a favorable TME as a targeted therapeutic approach in TNBC.

mTOR signalling pathway in stem cell bioactivities and angiogenesis potential

The mammalian target of rapamycin (mTOR) is a protein kinase that responds to different stimuli such as stresses, starvation and hypoxic conditions. The modulation of this effector can lead to the alteration of cell dynamic growth, proliferation, basal metabolism and other bioactivities. Considering this fact, the mTOR pathway is believed to regulate the diverse functions in several cell lineages. Due to the pleiotropic effects of the mTOR, we here, hypothesize that this effector can also regulate the bioactivity of stem cells in response to external stimuli pathways under physiological and pathological conditions. As a correlation, we aimed to highlight the close relationship between the mTOR signalling axis and the regenerative potential of stem cells in a different milieu. The relevant publications were included in this study using electronic searches of the PubMed database from inception to February 2023. We noted that the mTOR signalling cascade can affect different stem cell bioactivities, especially angiogenesis under physiological and pathological conditions. Modulation of mTOR signalling pathways is thought of as an effective strategy to modulate the angiogenic properties of stem cells.

BMP9 maintains the phenotype of HTR-8/Svneo trophoblast cells by activating the SDF1/CXCR4 pathway

BACKGROUND

Bone morphogenetic protein 9 (BMP9) has been shown to regulate processes such as angiogenesis, endothelial dysfunction, and tumorigenesis. However, the role of BMP9 in preeclampsia (PE) is unclear. The purpose of this study was to investigate the role and mechanism of BMP9 in PE.

METHODS

The effects of BMP9 on the viability, migration and invasion of HTR-8/Svneo cells were investigated by CCK-8 assay, wound healing assay and Transwell invasion assay. The effect of BMP9 on apoptosis of HTR-8/Svneo cells was detected by flow cytometry. Plasma levels of BMP9, SDF1 and CXCR4 were detected by ELISA kit. qRT-PCR and Western blot were used to detect the expression levels of each gene in the cells.

RESULTS

Overexpression of BMP9 promoted the proliferation and migration of trophoblast cells and inhibited apoptosis. Knockdown of BMP9 had the opposite effect. The levels of BMP9, SDF1 and CXCR4 in the plasma of PE patients were down-regulated, and BMP9 was positively correlated with the levels of SDF1 and CXCR4. BMP9 also significantly upregulated the mRNA and protein levels of SDF1 and CXCR4 in HTR-8/SVneo cells. Further mechanistic studies found that BMP9 promoted the migration and invasion of HTR-8/SVneo cells and inhibited apoptosis by activating the SDF1/CXCR4 pathway.

CONCLUSION

We demonstrate for the first time that BMP9 promoted the migration and invasion of HTR-8/SVneo cells and inhibits apoptosis by activating the SDF1/CXCR4 pathway. This suggests that BMP9 may be a biomarker molecule for PE.

The pathological role of C-X-C chemokine receptor type 4 (CXCR4) in colorectal cancer (CRC) progression; special focus on molecular mechanisms and possible therapeutics

Colorectal cancer (CRC) is comprised of transformed cells and non-malignant cells including cancer-associated fibroblasts (CAF), endothelial vasculature cells, and tumor-infiltrating cells. These nonmalignant cells, as well as soluble factors (e.g., cytokines), and the extracellular matrix (ECM), form the tumor microenvironment (TME). In general, the cancer cells and their surrounding TME can crosstalk by direct cell-to-cell contact and via soluble factors, such as cytokines (e.g., chemokines). TME not only promotes cancer progression through growth-promoting cytokines but also provides resistance to chemotherapy. Understanding the mechanisms of tumor growth and progression and the roles of chemokines in CRC will likely suggest new therapeutic targets. In this line, a plethora of reports has evidenced the critical role of chemokine receptor type 4 (CXCR4)/C-X-C motif chemokine ligand 12 (CXCL12 or SDF-1) axis in CRC pathogenesis. In the current review, we take a glimpse into the role of the CXCR4/CXCL12 axis in CRC growth, metastasis, angiogenesis, drug resistance, and immune escape. Also, a summary of recent reports concerning targeting CXCR4/CXCL12 axis for CRC management and therapy has been delivered.

CXC chemokine receptor 4 (CXCR4) blockade in cancer treatment

CXC chemokine receptor type 4 (CXCR4) is a member of the G protein-coupled receptors (GPCRs) superfamily and is specific for CXC chemokine ligand 12 (CXCL12, also known as SDF-1), which makes CXCL12/CXCR4 axis. CXCR4 interacts with its ligand, triggering downstream signaling pathways that influence cell proliferation chemotaxis, migration, and gene expression. The interaction also regulates physiological processes, including hematopoiesis, organogenesis, and tissue repair. Multiple evidence revealed that CXCL12/CXCR4 axis is implicated in several pathways involved in carcinogenesis and plays a key role in tumor growth, survival, angiogenesis, metastasis, and therapeutic resistance. Several CXCR4-targeting compounds have been discovered and used for preclinical and clinical cancer therapy, most of which have shown promising anti-tumor activity. In this review, we summarized the physiological signaling of the CXCL12/CXCR4 axis and described the role of this axis in tumor progression, and focused on the potential therapeutic options and strategies to block CXCR4.

Maternal hyperglycemia inhibits pulmonary vasculogenesis during mouse fetal lung development by promoting GβL Ubiquitination-dependent mammalian target of Rapamycin assembly

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with retarded lung development and poor lung health in offspring. Mammalian target of rapamycin (mTOR) is a key regulator of vasculogenesis and angiogenesis. The aim of this study was to investigate the role mTOR plays in pulmonary vasculogenesis during fetal lung development under maternal hyperglycemia.

METHODS

First, GDM was induced via streptozotocin injection in pregnant C57BL/6 mice before the radial alveolar count (RAC) in the fetal lungs was assessed using hematoxylin and eosin staining. The angiogenic ability of the cultured primary mouse fetal lung endothelial cells (MFLECs) was then assessed using the tube formation assay technique, while western blot and real-time polymerase chain reaction were performed to determine the expression of mTOR, regulatory-associated protein of mTOR (Raptor), rapamycin-insensitive companion of mTOR (Rictor), stress-activated protein kinase interacting protein 1 (Sin1), G protein beta subunit-like protein (GβL), Akt, tumor necrosis receptor associated factor-2 (TRAF2), and OTU deubiquitinase 7B (OTUD7B) in both the fetal lung tissues and the cultured MFLECs. Immunoprecipitation assays were conducted to evaluate the status of GβL-ubiquitination and the association between GβL and mTOR, Raptor, Rictor, and Sin1 in the cultured MFLECs.

RESULTS

The GDM fetal lungs exhibited a decreased RAC and reduced expression of von Willebrand factor, CD31, and microvessel density. The high glucose level reduced the tube formation ability in the MFLECs, with the mTOR, p-mTOR, p-Raptor, and TRAF2 expression upregulated and the p-Rictor, p-Sin1, p-Akt, and OTUD7B expression downregulated in both the GDM fetal lungs and the high-glucose-treated MFLECs. Meanwhile, GβL-ubiquitination was upregulated in the high-glucose-treated MFLECs along with an increased GβL/Raptor association and decreased GβL/Rictor and GβL/Sin1 association. Furthermore, TRAF2 knockdown inhibited the high-glucose-induced GβL-ubiquitination and GβL/Raptor association and restored the tube formation ability of the MFLECs.

CONCLUSION

Maternal hyperglycemia inhibits pulmonary vasculogenesis during fetal lung development by promoting GβL-ubiquitination-dependent mTORC1 assembly.

Remarkable sex-specific differences at single-cell resolution in neonatal hyperoxic lung injury

Exposure to supraphysiological concentrations of oxygen (hyperoxia) predisposes to bronchopulmonary dysplasia (BPD), which is characterized by abnormal alveolarization and pulmonary vascular development, in preterm neonates. Neonatal hyperoxia exposure is used to recapitulate the phenotype of human BPD in murine models. Male sex is considered an independent predictor for the development of BPD, but the main mechanisms underlying sexually dimorphic outcomes are unknown. Our objective was to investigate sex-specific and cell-type specific transcriptional changes that drive injury in the neonatal lung exposed to hyperoxia at single-cell resolution and delineate the changes in cell-cell communication networks in the developing lung. We used single-cell RNA sequencing (scRNAseq) to generate transcriptional profiles of >35,000 cells isolated from the lungs of neonatal male and female C57BL/6 mice exposed to 95% [Formula: see text] between PND1-5 (saccular stage of lung development) or normoxia and euthanized at PND7 (alveolar stage of lung development). ScRNAseq identified 22 cell clusters with distinct populations of endothelial, epithelial, mesenchymal, and immune cells. Our data identified that the distal lung vascular endothelium (composed of aerocytes and general capillary endothelial cells) is exquisitely sensitive to hyperoxia exposure with the emergence of an intermediate capillary endothelial population with both general capillaries (gCap) and aerocytes or alveolar capillaries (aCap) markers. We also identified a myeloid-derived suppressor cell population from the lung neutrophils. Sex-specific differences were evident in all lung cell subpopulations but were striking among the lung immune cells. Finally, we identified that the specific intercellular communication networks and the ligand-receptor pairs that are impacted by neonatal hyperoxia exposure.

Specificity Protein 1-Mediated Promotion of CXCL12 Advances Endothelial Cell Metabolism and Proliferation in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a rare yet devastating and incurable disease with few treatment options. The underlying mechanisms of PAH appear to involve substantial cellular proliferation and vascular remodeling, causing right ventricular overload and eventual heart failure. Recent evidence suggests a significant seminal role of the pulmonary endothelium in the initiation and promotion of PAH. Our previous work identified elevated reactive oxygen species (ROS)-producing enzyme NADPH oxidase 1 (NOX1) in human pulmonary artery endothelial cells (HPAECs) of PAH patients promoting endothelial cell proliferation in vitro. In this study, we interrogated chemokine CXCL12's (aka SDF-1) role in EC proliferation under the control of NOX1 and specificity protein 1 (Sp1). We report here that NOX1 can drive hypoxia-induced endothelial CXCL12 expression via the transcription factor Sp1 leading to HPAEC proliferation and migration. Indeed, NOX1 drove hypoxia-induced Sp1 activation, along with an increased capacity of Sp1 to bind cognate promoter regions in the CXCL12 promoter. Sp1 activation induced elevated expression of CXCL12 in hypoxic HPAECs, supporting downstream induction of expression at the CXCL12 promoter via NOX1 activity. Pathological levels of CXCL12 mimicking those reported in human PAH patient serum restored EC proliferation impeded by specific NOX1 inhibitor. The translational relevance of our findings is highlighted by elevated NOX1 activity, Sp1 activation, and CXCL12 expression in explanted lung samples from PAH patients compared to non-PAH controls. Analysis of phosphofructokinase, glucose-6-phosphate dehydrogenase, and glutaminase activity revealed that CXCL12 induces glutamine and glucose metabolism, which are foundational to EC cell proliferation. Indeed, in explanted human PAH lungs, demonstrably higher glutaminase activity was detected compared to healthy controls. Finally, infusion of recombinant CXCL12 into healthy mice amplified pulmonary arterial pressure, right ventricle remodeling, and elevated glucose and glutamine metabolism. Together these data suggest a central role for a novel NOX1-Sp1-CXCL12 pathway in mediating PAH phenotype in the lung endothelium.

Bioactive peptide inhibits acute myeloid leukemia cell proliferation by downregulating ALKBH5-mediated m6A demethylation of EIF4EBP1 and MLST8 mRNA

Purpose

N6-methyladenosine (m⁶A), the most prevalent mRNA modification, plays an essential role in tumorigenesis. Notably, increasing interest has been directed to bioactive peptides (BPs) with antitumor activities. Here, we set out to investigate the potential of the BP-regulated ALKBH5/MLST8/EIF4EBP1 axis on prevention and treatment of acute myeloid leukemia (AML).

Methods

The biological effects of BP on AML cells were detected by MTT and ApoLive-Glo™ multiplex assays. The role of BP in tumor growth was determined by a subcutaneous xenograft model. The ALKBH5/MLST8/EIF4EBP1 axis was identified as a potential BP target in AML via methylated RNA immunoprecipitation sequencing (MeRIP-seq) combined with RNA sequencing (RNA-seq). Western blot, RT-qPCR, MeRIP-qPCR, dual-luciferase reporter and RNA stability assays were performed to validate the function and mode of action of the BP-regulated ALKBH5/MLST8/EIF4EBP1 axis. The clinical relevance of the BP-regulated ALKBH5/MLST8/EIF4EBP1 axis in AML was confirmed by TCGA data analysis.

Results

We found that BP can inhibit AML cell proliferation and promote apoptosis in vitro, and repress AML tumor growth in vivo. Mechanistically, we found that BP downregulated ALKBH5 expression, which in turn repressed m⁶A demethylation of MLST8 and EIF4EBP1 mRNAs. Reduction of the m⁶A levels of MLST8 and EIF4EBP1 facilitated MLST8 and EIF4EBP1 mRNA decay, resulting in inhibition of AML cell proliferation. Furthermore, we found that the BP-regulated ALKBH5/MLST8/EIF4EBP1 axis closely correlates with AML patient prognosis.

Conclusions

Our data indicate that BP can inhibit acute myeloid leukemia cell proliferation by downregulating ALKBH5-mediated m⁶A demethylation of EIF4EBP1 and MLST8 mRNAs, which may have potential to prevent and treat this disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-022-00666-9.

ZDQ-0620, a Novel Phosphatidylinositol 3-Kinase Inhibitor, Inhibits Colorectal Carcinoma Cell Proliferation and Suppresses Angiogenesis by Attenuating PI3K/AKT/mTOR Pathway

The PI3K/AKT pathway plays a central role in human cancers, aberrant activation of this pathway is associated with tumorigenesis, cancer progression and angiogenesis. Based on the importance of the PI3K/AKT pathway in malignancies, we developed a 4-aminoquinazoline derivative, ZDQ-0620, initially envisioned as a novel pan-PI3K inhibitor. This study aimed to evaluate the potential target of ZDQ-0620 and its anticancer effect in human colorectal carcinoma (CRC). PI3K-kinase activity test showed IC50 of ZDQ-0620 against PI3Ka was 0.5 nM; molecular docking, CETSA assay and western blotting was further performed to predict ZDQ-0620 was a PI3K/AKT pathway inhibitor by targeting PI3K. To identify the effect of ZDQ-0620 on CRC cells, Sulforhodamine B (SRB) assay, flow cytometry, and Cell morphology analysis were conducted. The results showed that ZDQ-0620 inhibited the proliferation, migration and invasion of CRC cells, induced apoptosis through G0/G1 cell cycle arrest and mitochondrial pathway. Additionally, ZDQ-0620 inhibited the migration and tube formation of human umbilical vein endothelial cells (HUVECs). In vivo, neovascularization of rat aortic ring and chick chorioallantoic membrane (CAM) induced by VEGF was diminished when treated with ZDQ-0620. These results indicate that ZDQ-0620 induce apoptosis and anti-angiogenesis via inhibits the PI3K/AKT pathway. We suggest that the great potential of ZDQ-0620 as an effective treatment candidate against CRC.

TMAO-Activated Hepatocyte-Derived Exosomes Impair Angiogenesis via Repressing CXCR4

Objective: Trimethylamine-N-oxide (TMAO) was found to play crucial roles in vascular endothelial function. However, the exact molecular mechanisms are not yet entirely clear. Recently, we found that exosomes (Exos) isolated from TMAO-treated hepatocytes (TMAO-Exos) contained a distinctive profile of miRNAs compared to those from the TMAO-free group (Control-Exos). Furthermore, TMAO-Exos could notably promote inflammation, damage vascular endothelial cells (VECs), and impair endothelium-dependent vasodilation. This study aimed to further evaluate the effects of TMAO-Exos on VECs and explore the underlying mechanisms.

Methods: Exos were isolated from the hepatocyte culture supernatant with or without TMAO, using differential centrifugation. Then, VECs were treated with these Exos for 48 h and subjected to RNA-sequencing for detecting the changes of alternative polyadenylation (APA) and mRNA. After validation by qPCR and western blotting, the recombinant viruses were used to mediate the overexpression of C-X-C motif chemokine receptor 4 (CXCR4). The in vitro VEC function was evaluated by cell migration and tube formation, and in vivo angiogenesis was investigated in hindlimb ischemia models.

Results: Exos released from hepatocytes were differentially regulated by TMAO; both could be taken up by VECs; and furthermore, TMAO-Exos significantly reduced cell migration and tube formation in vitro and impaired perfusion recovery and angiogenesis after hindlimb ischemia, by down-regulating the CXCR4 expression. However, TMAO-Exos failed to regulate the splicing events, at least in this experimental setting, which suggested that TMAO-Exos may affect CXCR4 expression via an APA-independent manner.

Conclusions: Our findings revealed a novel indirect mechanism by which TMAO impaired endothelial function through stimulating hepatocytes to produce Exos that possessed distinctive activity. The crosstalk between the liver and vascular endothelial mediated by these Exos may offer a new target for restraining the harmful effects induced by TMAO.

FGD5 regulates endothelial cell PI3 kinase-β to promote neo-angiogenesis

Angiogenesis is required in embryonic development and tissue repair in the adult. Vascular endothelial growth factor (VEGF) initiates angiogenesis, and VEGF or its receptor is targeted therapeutically to block pathological angiogenesis. Additional pro-angiogenic cues, such as CXCL12 acting via the CXCR4 receptor, co-operate with VEGF/VEGFR2 to cue vascular patterning. We studied the role of FGD5, an endothelial Rho GTP/GDP exchange factor (RhoGEF), to regulate CXCR4-dependent signals in the endothelial cell (EC). Patient-derived renal cell carcinomas produce a complex milieu of growth factors that stimulated sprouting angiogenesis and endothelial tip cell differentiation ex vivo that was blocked by EC FGD5 loss. In a simplified model, CXCL12 augmented sprouting and tip gene expression under conditions where VEGF was limiting. CXCL12-stimulated tip cell differentiation was dependent on PI3 kinase (PI3K)-β activity. Knockdown of EC FGD5 abolished CXCR4 signaling to PI3K-β and Akt. Further, inhibition of Rac1, a Rho GTPase required for PI3K-β activity, recapitulated the signaling defects of FGD5 deficiency, suggesting that FGD5 may regulate PI3K-β activity through Rac1. Overexpression of a RhoGEF deficient, Dbl domain-deleted FGD5 mutant reduced CXCL12-stimulated Akt phosphorylation and failed to rescue PI3K signaling in native FGD5-deficient EC, indicating that FGD5 RhoGEF activity is required for FDG5 function. Endothelial expression of mutant PI3K-β with an inactivated Rho binding domain confirmed that CXCL12-stimulated PI3K activity in EC requires Rac1-GTP co-regulation. Together, this data identify the role of FGD5 to generate Rac1-GTP to regulate pro-angiogenic CXCR4-dependent PI3K-β signaling in EC. Inhibition of FGD5 activity may complement current angiogenesis inhibitor drugs.

Chemokine signaling in cancer-stroma communications

Cancer is a multi-faceted disease in which spontaneous mutation(s) in a cell leads to the growth and development of a malignant new organ that if left undisturbed will grow in size and lead to eventual death of the organism. During this process, multiple cell types are continuously releasing signaling molecules into the microenvironment, which results in a tangled web of communication that both attracts new cell types into and reshapes the tumor microenvironment as a whole. One prominent class of molecules, chemokines, bind to specific receptors and trigger directional, chemotactic movement in the receiving cell. Chemokines and their receptors have been demonstrated to be expressed by almost all cell types in the tumor microenvironment, including epithelial, immune, mesenchymal, endothelial, and other stromal cells. This results in chemokines playing multifaceted roles in facilitating context-dependent intercellular communications. Recent research has started to shed light on these ligands and receptors in a cancer-specific context, including cell-type specificity and drug targetability. In this review, we summarize the latest research with regards to chemokines in facilitating communication between different cell types in the tumor microenvironment.

Thyroid Hormone Enhances Angiogenesis and the Warburg Effect in Squamous Cell Carcinomas

Simple Summary

Cancer cells rewire their metabolism to promote growth, survival, proliferation, and long-term maintenance. Aerobic glycolysis is a prominent trait of many cancers; contextually, glutamine addiction, enhanced glucose uptake and aerobic glycolysis sustain the metabolic needs of rapidly proliferating cancer cells. Thyroid hormone (TH) is a positive regulator of tumor progression and metastatic conversion of squamous cell carcinoma (SCC). Accordingly, overexpression of the TH activating enzyme, D2, is associated with metastatic SCC. The aim of our study was to assess the ability of TH and its activating enzyme in promoting key tracts of cancer progression such as angiogenesis, response to hypoxia and metabolic adaptation. By performing in vivo and in vitro studies, we demonstrate that TH induces VEGF-A in cancer cells and fosters aerobic glycolysis inducing pro-glycolytic mediators, thus implying that TH signal attenuation represents a therapeutic tool to contrast tumor angiogenesis and tumor progression.

Abstract

Cancer angiogenesis is required to support energetic demand and metabolic stress, particularly during conditions of hypoxia. Coupled to neo-vasculogenesis, cancer cells rewire metabolic programs to sustain growth, survival and long-term maintenance. Thyroid hormone (TH) signaling regulates growth and differentiation in a variety of cell types and tissues, thus modulating hyper proliferative processes such as cancer. Herein, we report that TH coordinates a global program of metabolic reprogramming and induces angiogenesis through up-regulation of the VEGF-A gene, which results in the enhanced proliferation of tumor endothelial cells. In vivo conditional depletion of the TH activating enzyme in a mouse model of cutaneous squamous cell carcinoma (SCC) reduces the concentration of TH in the tumoral cells and results in impaired VEGF-A production and attenuated angiogenesis. In addition, we found that TH induces the expression of the glycolytic genes and fosters lactate production, which are key traits of the Warburg effect. Taken together, our results reveal a TH–VEGF-A–HIF1α regulatory axis leading to enhanced angiogenesis and glycolytic flux, which may represent a target for SCC therapy.

KDM2A Targets PFKFB3 for Ubiquitylation to Inhibit the Proliferation and Angiogenesis of Multiple Myeloma Cells

The lysine demethylase KDM2A (also known as JHDM1A or FBXL11) demethylates histone H3 at lysine K36 which lead to epigenetic regulation of cell proliferation and tumorigenesis. However, many biological processes are mediated by KDM2A independently by its histone demethylation activity. In the present study, we aimed to characterize the functional significance of KDM2A in multiple myeloma (MM) disease progression. Specifically, we defined that one of the key enzymes of glycolysis PFKFB3 (6-phosphofructo-2-kinase) is ubiquitylated by KDM2A which suppresses MM cell proliferation. Previous study showed that KDM2A and PFKFB3 promoted angiogenesis in various tumor cells. We further reveal that KDM2A targets PFKFB3 for ubiquitination and degradation to inhibit angiogenesis. Several angiogenic cytokines are also downregulated in MM. Clinically, MM patients with low KDM2A and high PFKFB3 levels have shown worse prognosis. These results reveal a novel function of KDM2A through ubiquitin ligase activity by targeting PFKFB3 to induce proliferation, glycolysis and angiogenesis in MM cells. The data provides a new potential mechanism and strategy for MM treatment.

Angiogenic Properties of Concentrated Growth Factors (CGFs): The Role of Soluble Factors and Cellular Components

Blood-derived concentrated growth factors (CGFs) represent a novel autologous biomaterial with promising applications in regenerative medicine. Angiogenesis is a key factor in tissue regeneration, but the role played by CGFs in vessel formation is not clear. The purpose of this study was to characterize the angiogenic properties of CGFs by evaluating the effects of its soluble factors and cellular components on the neovascularization in an in vitro model of angiogenesis. CGF clots were cultured for 14 days in cell culture medium; after that, CGF-conditioned medium (CGF-CM) was collected, and soluble factors and cellular components were separated and characterized. CGF-soluble factors, such as growth factors (VEGF and TGF-β1) and matrix metalloproteinases (MMP-2 and -9), were assessed by ELISA. Angiogenic properties of CGF-soluble factors were analyzed by stimulating human cultured endothelial cells with increasing concentrations (1%, 5%, 10%, or 20%) of CGF-CM, and their effect on cell migration and tubule-like formation was assessed by wound healing and Matrigel assay, respectively. The expression of endothelial angiogenic mediators was determined using qRT-PCR and ELISA assays. CGF-derived cells were characterized by immunostaining, qRT-PCR and Matrigel assay. We found that CGF-CM, consisting of essential pro-angiogenic factors, such as VEGF, TGF-β1, MMP-9, and MMP-2, promoted endothelial cell migration; tubule structure formation; and endothelial expression of multiple angiogenic mediators, including growth factors, chemokines, and metalloproteinases. Moreover, we discovered that CGF-derived cells exhibited features such as endothelial progenitor cells, since they expressed the CD34 stem cell marker and endothelial markers and participated in the neo-angiogenic process. In conclusion, our results suggest that CGFs are able to promote endothelial angiogenesis through their soluble and cellular components and that CGFs can be used as a biomaterial for therapeutic vasculogenesis in the field of tissue regeneration.

The biological role of the CXCL12/CXCR4 axis in esophageal squamous cell carcinoma

Esophageal cancer is the eighth most common malignant tumor and the sixth leading cause of cancer-related death worldwide. Esophageal squamous cell carcinoma (ESCC) is the main histological type of esophageal cancer, and accounts for 90% of all cancer cases. Despite the progress made in surgery, chemotherapy, and radiotherapy, the mortality rate from esophageal cancer remains high, and the overall 5-year survival rate is less than 20%, even in developed countries. The C-X-C motif chemokine ligand 12 (CXCL12) is a member of the CXC chemokine subgroup, which is widely expressed in a variety of tissues and cells. CXCL12 participates in the regulation of many physiological and pathological processes by binding to its specific receptor, C-X-C motif chemokine receptor type 4 (CXCR4), where it causes embryonic development, immune response, and angiogenesis. In addition, increasing evidence indicates that the CXCL12/CXCR4 axis plays an important role in the biological processes of tumor cells. Studies have shown that CXCL12 and its receptor, CXCR4, are highly expressed in ESCC. This abnormal expression contributes to tumor proliferation, lymph node and distant metastases, and worsening prognosis. At present, antagonists and imaging agents against CXCL12 or CXCR4 have been developed to interfere with the malignant process and monitor metastasis of tumors. This article summarizes the structure, function, and regulatory mechanism of CXCL12/CXCR4 and its role in the malignancy of ESCC. Current results from preclinical research targeting CXCL12/CXCR4 are also summarized to provide a reference for the clinical diagnosis and treatment of ESCC.

SNHG17 promotes the proliferation and migration of colorectal adenocarcinoma cells by modulating CXCL12-mediated angiogenesis

Background

Colorectal adenocarcinoma (CRA) is one of the leading causes of cancer-related deaths in the world. Long non-coding RNAs (lncRNAs) have been implicated to be effective regulators in the disease course of human cancers, including CRA. Small nucleolar RNA host gene 17 (SNHG17) belongs to lncRNAs, and it has been reported in breast cancer and gastric cancer. However, the function of SNHG17 and its mechanism in CRA progression remain largely unknown. In this study, we attended to shedding some light on the role of SNHG17 in CRA.

Methods

RT-qPCR was used to assess SNHG17 expression in CRA cells. CCK-8 assay, colony formation and transwell assay were carried out to detect the regulatory effect of SNHG17 silencing on CRA cell proliferation and migration. The angiogenesis of SNHG7-downregulated CRA cells was analyzed by tube formation assay. Mechanism experiments were conducted to identify the interaction between miR-23a-3p and SNHG17 or C-X-C motif chemokine ligand 12 (CXCL12).

Results

SNHG17 possessed with high expression in CRA cells. Knockdown of SNHG17 caused the inhibition on CRA cell proliferation and migration. SNHG17 promoted CRA cell proliferation and migration by sponging miR-23a-3p to upregulate CXCL12.

Conclusion

SNHG17 promotes the proliferation and migration of CRA cells by inhibiting miR-23a-3p to modulate CXCL12-mediated angiogenesis.

Slug regulates the Dll4-Notch-VEGFR2 axis to control endothelial cell activation and angiogenesis

Slug (SNAI2), a member of the well-conserved Snail family of transcription factors, has multiple developmental roles, including in epithelial-to-mesenchymal transition (EMT). Here, we show that Slug is critical for the pathological angiogenesis needed to sustain tumor growth, and transiently necessary for normal developmental angiogenesis. We find that Slug upregulation in angiogenic endothelial cells (EC) regulates an EMT-like suite of target genes, and suppresses Dll4-Notch signaling thereby promoting VEGFR2 expression. Both EC-specific Slug re-expression and reduced Notch signaling, either by γ-secretase inhibition or loss of Dll4, rescue retinal angiogenesis in SlugKO mice. Conversely, inhibition of VEGF signaling prevents excessive angiogenic sprouting of Slug overexpressing EC. Finally, endothelial Slug (but not Snail) is activated by the pro-angiogenic factor SDF1α via its canonical receptor CXCR4 and the MAP kinase ERK5. Altogether, our data support a critical role for Slug in determining the angiogenic response during development and disease.

Slug supports heart development and tumor metastasis, but its role in blood vessel formation is less clear. Here the authors show that endothelial cell-expressed Slug regulates both physiologic and pathological angiogenesis, at least in part through the modulation of Notch signalling.

S100A8 and S100A9 promote endothelial cell activation through the RAGE‑mediated mammalian target of rapamycin complex 2 pathway

S100 calcium binding protein A8 (S100A8) and A9 (S100A9) belong to the S100 family of calcium-binding proteins and have important roles in inflammation. They increase endothelial cell proliferation, thereby affecting inflammation, angiogenesis and tumorigenesis. However, the mechanism of action of S100A8/9 in endothelial cells needs further study. Therefore, the present study sought to investigate the effects of S100A8/9 on the proliferation and angiogenesis of human umbilical vein endothelial cells (HUVECs) and their mechanism of action. The viability of HUVECs was determined through a Cell Counting Kit-8 assay. The effect of S100A8/9 on the proliferation of HUVECs was detected by flow cytometry. Migration was evaluated by a Transwell migration assay. Apoptosis was evaluated by Annexin V-FITC and PI staining via flow cytometry. Western blot analysis and reverse transcription-quantitative polymerase chain reaction assays were performed to evaluate the activation of the phosphatidylinositol 3-phosphate kinase (PI3K)/Akt/mTOR pathway and mTOR complex 2 (mTORC2). We previously confirmed that S100A8/9 were consistently overexpressed at 1 and 7 days post-surgery in a rabbit vein graft model, which is the period when apoptosis changes to proliferation in neointimal hyperplasia. In the present study, proliferation, viability and migration were increased after treating HUVECs with S100A8/9. S100A8/9 stimulated the PI3K/Akt/mTOR pathway and mTORC2, which was significantly suppressed by a receptor for advanced glycation end products (RAGE)-blocking antibody. Furthermore, depleting expression of RAGE or mTORC2 protein components (rapamycin-insensitive companion of mTOR) by small interfering RNA was found to reduce the cell viability, migration and angiogenesis of S100A8/9-treated HUVECs. The development of neointimal hyperplasia is a complex process initiated by damage to endothelial cells. In conclusion, S100A8/9 has an important role in intimal hyperplasia by promoting cell growth and angiogenesis via RAGE signaling and activation of mTORC2.

Regulation of mTORC2 Signaling

Mammalian target of rapamycin (mTOR), a serine/threonine protein kinase and a master regulator of cell growth and metabolism, forms two structurally and functionally distinct complexes, mTOR complex 1 (mTORC1) and mTORC2. While mTORC1 signaling is well characterized, mTORC2 is relatively poorly understood. mTORC2 appears to exist in functionally distinct pools, but few mTORC2 effectors/substrates have been identified. Here, we review recent advances in our understanding of mTORC2 signaling, with particular emphasis on factors that control mTORC2 activity.

The CCL20-CCR6 Axis in Cancer Progression

Chemokines, which are basic proteins that exert their effects via G protein-coupled receptors and a subset of the cytokine family, are mediators deeply involved in leukocyte migration during an inflammatory reaction. Chemokine (C-C motif) ligand 20 (CCL20), also known as macrophage inflammatory protein (MIP)-3α, liver activation regulated chemokine (LARC), and Exodus-1, is a small protein that is physiologically expressed in the liver, colon, and skin, is involved in tissue inflammation and homeostasis, and has a specific receptor C-C chemokine receptor 6 (CCR6). The CCL20-CCR6 axis has long been known to be involved in inflammatory and infectious diseases, such as rheumatoid arthritis and human immunodeficiency virus infections. Recently, however, reports have shown that the CCL20-CCR6 axis is associated with several cancers, including hepatocellular carcinoma, colorectal cancer, breast cancer, pancreatic cancer, cervical cancer, and kidney cancer. The CCL20-CCR6 axis promotes cancer progression directly by enhancing migration and proliferation of cancer cells and indirectly by remodeling the tumor microenvironment through immune cell control. The present article reviewed the role of the CCL20-CCR6 axis in cancer progression and its potential as a therapeutic target.

Tumor microenvironment in chemoresistance, metastasis and immunotherapy of pancreatic cancer

Pancreatic cancer (PC) is a fatal disease with high malignancy and difficult for early diagnosis. PC causes more than 400,000 patient deaths world widely and becomes the severe health problems. The tumor microenvironment (TME) is comprised of acellular stroma, pancreatic stellate cells, immune cells, and soluble factors. TME is maintained by continuous cell-matrix and cell-cell interactions. TME induced by the interaction among pancreatic cancer cells, epithelial cells and stromal cells is essential for the progression of PC and leads to resistance to chemotherapy. Components in the microenvironment can also promote the formation of connective tissue in the primary or metastatic site, or promote the metastatic ability of PC by enhancing angiogenesis, epithelial-mesenchymal transformation, and lymph angiogenesis. In addition, the TME also leaves pancreatic cancer unsusceptible to different immunotherapeutic strategies. In this review, we summarized the current knowledge about TME in PC. And the focus was placed on the role of TME in chemotherapeutic resistance and metastasis in the field of PC. And we also paid attention to the immunological therapy targeting the TME, aiming to provide the novel therapy for pancreatic cancer.

Activation of CXCR7 alleviates cardiac insufficiency after myocardial infarction by promoting angiogenesis and reducing apoptosis

Angiogenesis is an important pathway for revascularization of ischemic tissues after acute myocardial infarction (AMI). It is unclear what role CXCR7 plays in angiogenesis in the ischemic area after AMI, although some researchers have shown that the activation of CXCR7 protectsthe heart under those conditions. Here, we hypothesize that the activation of CXCR7 promotes angiogenesis, reduces cell apoptosis and alleviates cardiac deficiency after AMI. C57BL/6 J mice were subjected to AMI and treated with TC14012 (10 mg/kg) for 24 days. HUVECs were cultured in a hypoxic (2% O₂) environment to generate a model of hypoxia. CXCR7 was knocked down in HUVECs by sh-CXCR7 transfection, and CXCR7 was activated by TC14012 (30 μM) treatment. The results showed that CXCR7 was downregulated in infarcted heart tissue and hypoxic HUVECs. The global activation of CXCR7 may alleviate the decrease in cardiac function indexes - (ejection fraction and fraction shortening), and reduce infarct size after AMI.. Moreover, CXCR7 activation has been shown to enhance the level of angiogenesis in ischemic heart tissue. In vitro, hypoxia-induced angiogenic functional loss and apoptosis are aggravated by CXCR7 knockdown in HUVECs. Both angiogenic impairment and cell apoptosis are rescued by CXCR7 activation. In conclusion, the present study indicates that activation of CXCR7 plays an important protective role for ischemic cells in hypoxic endothelial cells and AMI model mice by promoting angiogenesis and reducing apoptosis, which suggests that CXCR7 may be a potential therapeutic target to rescue the ischemic myocardium..

The expression and biological function of chemokine CXCL12 and receptor CXCR4/CXCR7 in placenta accreta spectrum disorders

Objectives

Investigation of mechanism related to excessive invasion of trophoblast cells in placenta accreta spectrum disorders (PAS) provides more strategies and ideas for clinical diagnosis and treatment.

Materials and Methods

Blood and placental samples were collected from included patients. The distribution and expression of CXCL12, CXCR4 and CXCR7 proteins in the paraffin of placental tissue in the included cases were analysed, and we analyse the downstream pathways or key proteins involved in cell invasion.

Results

Firstly, our results determined that CXCL12 and CXCR4/CXCR7 were increased in extravillous trophoblastic cell (CXCL12: P < .001; CXCR4: P < .001; CXCR7: P < .001), and the expression levels were closely related to the invasion depth of trophoblastic cells. Secondly, CXCL12 has the potential to become a biochemical indicator of PAS since the high expression of placental trophoblast CXCL12 may be an important source of blood CXCL12. Using lentivirus‐mediated RNA interference and overexpression assay, it was found that both chemokine CXCL12 and receptor CXCR4/CXCR7 are associated with regulation of trophoblast cell proliferation, migration and invasion. Further results proved that through the activating the phosphorylation and increasing the expression of MLC and AKT proteins in the Rho/rock, PI3K/AKT signalling pathway, CXCL12, CXCR4 and CXCR7 could up‐regulate the expression of RhoA, Rac1 and Cdc42 proteins to promote the migration and invasion of extravillous trophoblastic cell and ultimately formate the placenta accrete compare to the normal placenta.

Conclusions

Our research proved that trophoblasts may contribute to a PAS‐associated increase in CXCL12 levels in maternal blood. CXCL12 is not only associated with biological roles of PAS, but may also be potential for prediction of PAS.

Constitutive and stimulated macropinocytosis in macrophages: roles in immunity and in the pathogenesis of atherosclerosis

Macrophages respond to several stimuli by forming florid membrane ruffles that lead to fluid uptake by macropinocytosis. This type of induced macropinocytosis, executed by a variety of non-malignant and malignant cells, is initiated by transmembrane receptors and is involved in nutrient acquisition and mTOR signalling. However, macrophages also perform a unique type of constitutive ruffling and macropinocytosis that is dependent on the presence of extracellular calcium. Calcium-sensing receptors are responsible for this activity. This distinct form of macropinocytosis enables macrophages to continuously sample their microenvironment for antigenic molecules and for pathogen- and danger-associated molecular patterns, as part of their immune surveillance functions. Interestingly, even within the monocyte lineage, there are differences in macropinocytic ability that reflect the polarized functional roles of distinct macrophage subsets. This review discusses the shared and distinct features of both induced and constitutive macropinocytosis displayed by the macrophage lineage and their roles in physiology, immunity and pathophysiology. In particular, we analyse the role of macropinocytosis in the uptake of modified low-density lipoprotein (LDL) and its contribution to foam cell and atherosclerotic plaque formation. We propose a combined role of scavenger receptors and constitutive macropinocytosis in oxidized LDL uptake, a process we have termed 'receptor-assisted macropinocytosis'. This article is part of the Theo Murphy meeting issue 'Macropinocytosis'.

Silencing MicroRNA-137-3p, which Targets RUNX2 and CXCL12 Prevents Steroid-induced Osteonecrosis of the Femoral Head by Facilitating Osteogenesis and Angiogenesis

The main pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH) includes decreased osteogenic capacity of bone marrow-derived mesenchymal stem cells (BMSCs) and damaged blood supply to the femoral head. MicroRNAs (miRNAs) have been shown to play prominent roles in SONFH development. However, there is no report that a specific miRNA targeting two genes in two different pathogenic pathways has been applied to this disease. The present study investigated the effects of transplantation of miR-137-3p-silenced BMSCs on the prevention and early treatment of SONFH. First, western blotting and dual luciferase assays were employed to verify that miR-137-3p directly targets Runx2 and CXCL12. Then, silencing of miR-137-3p was found to facilitate osteogenic differentiation of BMSCs, which was confirmed by alkaline phosphatase (ALP) staining, alizarin red staining and qRT-PCR. Silencing of miR-137-3p also promoted angiogenesis by human umbilical vein endothelial cells (HUVECs) in the presence or absence of glucocorticoids. Thereafter, overexpression of Runx2 and CXCL12 without the 3′ untranslated region (3′UTR) partially rescued the effects of miR-137-3p on osteogenesis and angiogenesis, respectively. This finding further supported the hypothesis that miR-137-3p exerts its functions partly by regulating the genes, Runx2 and CXCL12. We also demonstrated that SONFH was partially prevented by transplantation of miR-137-3p-silenced BMSCs into a rat model. Micro-CT and histology showed that the transplantation of miR-137-3p-silenced BMSCs significantly improved bone regeneration. Additionally, the results of enzyme-linked immunosorbent assays (ELISA) and flow cytometry suggested that stromal cell-derived factor-1α (SDF-1α) and endothelial progenitor cells (EPCs) participated in the process of vascular repair. Taken together, these findings show that silencing of miR-137-3p directly targets the genes, Runx2 and CXCL12, which can play critical roles in SONFH repair by facilitating osteogenic differentiation and mobilizing EPCs.

The enhancement of glycolysis regulates pancreatic cancer metastasis

Pancreatic ductal adenocarcinoma is prone to distant metastasis and is expected to become the second leading cause of cancer-related death. In an extremely nutrient-deficient and hypoxic environment resulting from uncontrolled growth, vascular disturbances and desmoplastic reactions, pancreatic cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. Notably, pancreatic cancer cells show extensive enhancement of glycolysis, including glycolytic enzyme overexpression and increased lactate production, and this is caused by mitochondrial dysfunction, cancer driver genes, specific transcription factors, a hypoxic tumor microenvironment and stromal cells, such as cancer-associated fibroblasts and tumor-associated macrophages. The metabolic switch from oxidative phosphorylation to glycolysis in pancreatic cancer cells regulates the invasion-metastasis cascade by promoting epithelial-mesenchymal transition, tumor angiogenesis and the metastatic colonization of distant organs. In addition to aerobic glycolysis, oxidative phosphorylation also plays a critical role in pancreatic cancer metastasis in ways that remain unclear. In this review, we expound on the intracellular and extracellular causes of the enhancement of glycolysis in pancreatic cancer and the strong association between glycolysis and cancer metastasis, which we expect will yield new therapeutic approaches targeting cancer metabolism.

Urine proteome changes in rats subcutaneously inoculated with approximately ten tumor cells

Background

Biomarkers are changes associated with the disease. Urine is not subject to homeostatic control and therefore accumulates very early changes, making it an ideal biomarker source. Usually, we have performed urinary biomarker studies involving at least thousands of tumor cells. However, no tumor starts from a thousand tumor cells. We therefore examined urine proteome changes in rats subcutaneously inoculated with approximately ten tumor cells.

Methods

Here, we serially diluted Walker-256 carcinosarcoma cells to a concentration of 10²/mL and subcutaneously inoculated 0.1 mL of these cells into nine rats. The urine proteomes on days 0, 13 and 21 were analyzed by liquid chromatography coupled with tandem mass spectrometry.

Results

Hierarchical clustering analysis showed that the urine proteome of each sample at three time points were clustered into three clusters, indicating the good consistency of these nine rats when inoculated with the same limited tumor cells. Differential proteins on days 13 and 21 were mainly associated with cell adhesion, autophagic cell death, changes in extracellular matrix organization, angiogenesis, and the pentose phosphate pathway. All of these enriched functional processes were reported to contribute to tumor progression and could not be enriched through random allocation analysis.

Conclusions

Our results indicated that (1) the urine proteome reflects changes associated with cancer even with only approximately ten tumor cells in the body and that (2) the urine proteome reflects pathophysiological changes in the body with extremely high sensitivity and provides potential for a very early screening process of clinical patients.

Plumbagin Restrains Hepatocellular Carcinoma Angiogenesis by Stromal Cell-Derived Factor (SDF-1)/CXCR4-CXCR7 Axis

BACKGROUND Anti-angiogenic therapy has recently emerged as a highly promising therapeutic strategy for treating hepatocellular carcinoma (HCC). MATERIAL AND METHODS We assessed cellular proliferation, invasion, and activation of growth factors (VEGF and IL-8) with SDF-1 induced in the hepatocellular carcinoma cell line SMMC-7721, and this progression was limited by plumbagin (PL). The human umbilical vein endothelial cell line HUVEC was co-cultured with SDF-1-induced SMMC-7721, and the expressions of CXCR7, CXCR4, and PI3K/Akt pathways after PL treatment were detected by RT-PCR and Western blot analysis. RESULTS The treatment of the hepatoma cell line SMMC-7721 with SDF-1 resulted in enhanced secretion of the angiogenic factors, IL-8 and VEGF, and shows that these stimulatory effects are abolished by PL. The study further demonstrated that PL not only abolishes SDF-1-induced formation of endothelial tubes, but also inhibits expression of CXCR4 and CXCR7, and partially prevents activation of angiogenic signaling pathways. CONCLUSIONS The effect of PL on the SDF-1-CXCR4/CXCR7 axis has become an attractive target for inhibiting angiogenesis in hepatoma cells. Our results provide more evidence for the clinical application of PL as part of traditional Chinese medicine in modern cancer treatment.

CXCL12 loaded-dermal filler captures CXCR4 expressing melanoma circulating tumor cells

Development of distant metastasis relies on interactions between cancer and stromal cells. CXCL12, also known as stromal-derived factor 1α (SDF-1α), is a major chemokine constitutively secreted in bone marrow, lymph nodes, liver and lung, playing a critical role in the migration and seeding of neoplastic cells. CXCL12 activates the CXCR4 receptor that is overexpressed in several human cancer cells. Recent evidence reveals that tumors induce pre-metastatic niches in target organ producing tumor-derived factors. Pre-metastatic niches represent a tumor growth-favoring microenvironment in absence of cancer cells. A commercially available dermal filler, hyaluronic acid (HA) -based gel, loaded with CXCL12 (CLG) reproduced a "fake" pre-metastatic niche. In vitro, B16-hCXCR4-GFP, human cxcr4 expressing murine melanoma cells efficiently migrated toward CLG. In vivo, CLGs and empty gels (EGs) were subcutaneously injected into C57BL/6 mice and 5 days later B16-hCXCR4-GFP cells were intravenously inoculated. CLGs were able to recruit a significantly higher number of B16-hCXCR4-GFP cells as compared to EGs, with reduced lung metastasis in mice carrying CLG. CLG were infiltrated by higher number of CD45-positive leukocytes, mainly neutrophils CD11b+Ly6G+ cells, myeloid CD11b+Ly6G- and macrophages F4/80. CLG recovered cells recapitulated the features of B16-hCXCR4-GFP (epithelial, melanin rich, MELAN A/ S100/ c-Kit/CXCR4 pos; α-SMA neg). Thus a HA-based dermal filler loaded with CXCL12 can attract and trap CXCR4+tumor cells. The CLG trapped cells can be recovered and biologically characterized. As a corollary, a reduction in CXCR4 dependent lung metastasis was detected.

Revisiting mTOR inhibitors as anticancer agents

The mammalian target of rapamycin (mTOR) is a highly conserved serine/threonine kinase that regulates a variety of cellular processes, influencing diverse pathological conditions including a variety of cancers. Accordingly, therapies that target mTOR as anticancer agents benefit patients in various clinical settings. It is therefore important to fully investigate mTOR signaling at a molecular level and corresponding mTOR inhibitors to identify additional clinical opportunities of targeting mTOR in cancers. In this review, we introduce the function and regulation of the mTOR signaling pathway and organize and summarize the different roles of mTOR in cancers and a variety of mTOR inhibitors that can be used as anticancer agents. This article aims to enlighten and guide the development of mTOR-targeted anticancer agents in the future.

Radionuclide-Labeled Peptides for Imaging and Treatment of CXCR4- Overexpressing Malignant Tumors

Malignant tumors are a major cause of death. The lack of methods that provide an early diagnosis and adequate treatment of cancers is the main obstacle to precision medicine. The C-X-C chemokine receptor 4 (CXCR4) is overexpressed in various tumors and plays a key role in tumor pathogenesis. Therefore, CXCR4-targeted molecular imaging can quickly and accurately detect and quantify CXCR4 abnormalities in real time. The expression level and activation status of CXCR4 are very important for screening susceptible populations and providing an accurate diagnosis and optimal treatment. In view of the fact that radionuclide-labeled peptides have become widely used for the diagnosis and treatment of tumors, this manuscript reviews the potential of different radionuclide-labeled peptide inhibitors for the targeted imaging of CXCR4- positive tumors and targeted treatment. The article also discusses the specificity and in vivo distribution of radionuclide-labeled peptide inhibitors, and translation of these inhibitors to the clinic.

The significance of chemokines in diffuse large B-cell lymphoma: a systematic review and future insights

Despite the progress made in molecular and clinical research, patients with diffuse large B-cell lymphoma (DLBCL) still have a bad prognosis. Recently, chemokines/chemokine receptors have become the subject of interest in relation to DLBCL. Studies have demonstrated the important role of chemokines/chemokine receptors in the communication between DLBCL cells and tumor microenvironment. Studies have also reported the ability of chemokines/chemokine receptors in promoting the proliferation and invasion of DLBCL cells. Here, we summarize the data on mechanisms of DLBCL supporting the involvement of chemokine/chemokine receptor changes. We focus on the available evidence regarding chemokines/chemokine receptors as biomarkers and therapeutic targets for DLBCL.

Involvement of CXCR4 in Normal and Abnormal Development

CXC motif chemokine receptor type 4 (CXCR4) is associated with normal and abnormal development, including oncogenesis. The ligand of CXCR4 is stromal cell-derived factor (SDF), also known as CXC motif ligand (CXCL) 12. Through the SDF-1/CXCR4 axis, both homing and migration of hematopoietic (stem) cells are regulated through niches in the bone marrow. Outside of the bone marrow, however, SDF-1 can recruit CXCR4-positive cells from the bone marrow. SDF/CXCR4 has been implicated in the maintenance and/or differentiation of stemness, and tissue-derived stem cells can be associated with SDF-1 and CXCR4 activity. CXCR4 plays a role in multiple pathways involved in carcinogenesis and other pathologies. Here, we summarize reports detailing the functions of CXCR4. We address the molecular signature of CXCR4 and how this molecule and cells expressing it are involved in either normal (maintaining stemness or inducing differentiation) or abnormal (developing cancer and other pathologies) events. As a constituent of stem cells, the SDF-1/CXCR4 axis influences downstream signal transduction and the cell microenvironment.

Effect of Stromal Cells in Tumor Microenvironment on Metastasis Initiation

The cellular environment where tumor cells reside is called the tumor microenvironment (TME), which consists of borders, blood vessels, lymph vessels, extracellular matrix (ECM), stromal cells, immune/inflammatory cells, secreted proteins, RNAs and small organelles. By dynamically interacting with tumor cells, stromal cells participate in all stages of tumor initiation, progression, metastasis, recurrence and drug response, and consequently, affect the fate of patients. During the processes of tumor evolution and metastasis initiation, stromal cells in TME also experience some changes and play roles in both the suppression and promotion of metastasis, while the overall function of stromal cells is beneficial for cancer cell survival and movement. In this review, we examine the effects of stromal cells in TME on metastasis initiation, including angiogenesis, epithelial-mesenchymal transition (EMT) and invasion. We also highlight functions of proteins, RNAs and small organelles secreted by stromal cells in their influences on multiple stages of tumor metastasis.

Transient and Local Expression of Chemokine and Immune Checkpoint Traps To Treat Pancreatic Cancer

Pancreatic tumors are known to be resistant to immunotherapy due to the extensive immune suppressive tumor microenvironment (TME). We hypothesized that CXCL12 and PD-L1 are two key molecules controlling the immunosuppressive TME. Fusion proteins, called traps, designed to bind with these two molecules with high affinity (K_d = 4.1 and 0.22 nM, respectively) were manufactured and tested for specific binding with the targets. Plasmid DNA encoding for each trap was formulated in nanoparticles and intravenously injected to mice bearing orthotopic pancreatic cancer. Expression of traps was mainly seen in the tumor, and secondarily, accumulations were primarily in the liver. Combination trap therapy shrunk the tumor and significantly prolonged the host survival. Either trap alone only brought in a partial therapeutic effect. We also found that CXCL12 trap allowed T-cell penetration into the tumor, and PD-L1 trap allowed the infiltrated T-cells to kill the tumor cells. Combo trap therapy also significantly reduced metastasis of the tumor cells to other organs. We conclude that the trap therapy significantly modified the immunosuppressive TME to allow the host immune system to kill the tumor cells. This can be an effective therapy in clinical settings.

CXCL12 enhances angiogenesis through CXCR7 activation in human umbilical vein endothelial cells

Angiogenesis is the process by which new vessels form from existing vascular networks. Human umbilical vein endothelial cells (HUVECs) may contribute to the study of vascular repair and angiogenesis. The chemokine CXCL12 regulates multiple cell functions, including angiogenesis, mainly through its receptor CXCR4. In contrast to CXCL12/CXCR4, few studies have described roles for CXCR7 in vascular biology, and the downstream mechanism of CXCR7 in angiogenesis remains unclear. The results of the present study showed that CXCL12 dose-dependently enhanced angiogenesis in chorioallantoic membranes (CAMs) and HUVECs. The specific activation of CXCR7 with TC14012 (a CXCR7 agonist) resulted in the significant induction of tube formation in HUVECs and in vivo. Further evidence suggested that CXCL12 induced directional polarization and migration in the HUVECs, which is necessary for tube formation. Moreover, CXCR7 translocalization was observed during the polarization of HUVECs in stripe assays. Finally, treatment with TC14012 also significantly increased PI3K/Akt phosphorylation, and tube formation was blocked by treating HUVECs with an Akt inhibitor. Overall, this study indicated that CXCL12-stimulated CXCR7 acts as a functional receptor to activate Akt for angiogenesis in HUVECs and that CXCR7 may be a potential target molecule for endothelial regeneration and repair after vascular injury.

Angiogenesis in metabolic-vascular disease

Angiogenesis, literally formation of new blood vessels, is the main process through which the vascular system expands during embryonic and postnatal development. Endothelial cells, which constitute the inner lining of all blood vessels, are typically in a quiescent state in the healthy adult organism. However, in vascular and metabolic diseases, the endothelium becomes unstable and dysfunctional. The resulting tissue hypoxia may thereby induce pathological angiogenesis, which is a hallmark of disease conditions like cancer or diabetic retinopathy. However, recent evidence suggests that angiogenesis is also a major player in the context of further metabolic diseases, especially in obesity. In particular, deregulated angiogenesis is linked with adipose tissue dysfunction and insulin resistance. On the other hand, signalling pathways, such as the PI3K pathway, may regulate metabolic activities in the endothelium. Endothelial cell metabolism emerges as an important regulator of angiogenesis. This review summarises the role of angiogenesis in metabolic-vascular disease, with specific focus on the role of angiogenesis in obesity-related metabolic dysfunction and on signaling pathways, especially PI3K, linking cell metabolism to endothelial function.

Recapitulating the human tumor microenvironment: Colon tumor-derived extracellular matrix promotes angiogenesis and tumor cell growth

Extracellular matrix (ECM) is an essential and dynamic component of all tissues and directly affects cellular behavior by providing both mechanical and biochemical signaling cues. Changes in ECM can alter tissue homeostasis, potentially leading to promotion of cellular transformation and the generation of tumors. Therefore, understanding ECM compositional changes during cancer progression is vital to the development of targeted treatments. Previous efforts to reproduce the native 3D cellular microenvironment have utilized protein gels and scaffolds that incompletely recapitulate the complexity of native tissues. Here, we address this problem by extracting and comparing ECM from normal human colon and colon tumor that had metastasized to liver. We found differences in protein composition and stiffness, and observed significant differences in vascular network formation and tumor growth in each of the reconstituted matrices, both in vitro and in vivo. We studied free/bound ratios of NADH in the tumor and endothelial cells using Fluorescence Lifetime Imaging Microscopy as a surrogate for the metabolic state of the cells. We observed that cells seeded in tumor ECM had higher relative levels of free NADH, consistent with a higher glycolytic rate, than those seeded in normal ECM. These results demonstrate that the ECM plays an important role in the growth of cancer cells and their associated vasculature.