Leptin promotes VEGF-C production and induces lymphangiogenesis by suppressing miR-27b in human chondrosarcoma cells

NAMPT enhances LOX expression and promotes metastasis in human chondrosarcoma cells by inhibiting miR-26b-5p synthesis

Chondrosarcoma is a malignant bone tumor that emerges from abnormalities in cartilaginous tissue and is related with lung metastases. Nicotinamide phosphoribosyltransferase (NAMPT) is an adipocytokine reported to enhance tumor metastasis. Our results from clinical samples and the Gene Expression Omnibus data set reveal that NAMPT levels are markedly higher in chondrosarcoma patients than in normal individuals. NAMPT stimulation significantly increased lysyl oxidase (LOX) production in chondrosarcoma cells. Additionally, NAMPT increased LOX-dependent cell migration and invasion in chondrosarcoma by suppressing miR-26b-5p generation through the c-Src and Akt signaling pathways. Overexpression of NAMPT promoted chondrosarcoma metastasis to the lung in vivo. Furthermore, knockdown of LOX counteracted NAMPT-facilitated metastasis. Thus, the NAMPT/LOX axis presents a novel target for treating the metastasis of chondrosarcoma.

Emerging Treatments Targeting the Tumor Microenvironment for Advanced Chondrosarcoma

Chondrosarcoma (ChS), a malignant cartilage-producing tumor, is the second most frequently diagnosed osseous sarcoma after osteosarcoma. It represents a very heterogeneous group of malignant chemo- and radiation-resistant neoplasms, accounting for approximately 20% of all bone sarcomas. The majority of ChS patients have a good prognosis after a complete surgical resection, as these tumors grow slowly and rarely metastasize. Conversely, patients with inoperable disease, due to the tumor location, size, or metastases, represent a great clinical challenge. Despite several genetic and epigenetic alterations that have been described in distinct ChS subtypes, very few therapeutic options are currently available for ChS patients. Therefore, new prognostic factors for tumor progression as well as new treatment options have to be explored, especially for patients with unresectable or metastatic disease. Recent studies have shown that a correlation between immune infiltrate composition, tumor aggressiveness, and survival does exist in ChS patients. In addition, the intra-tumor microvessel density has been proven to be associated with aggressive clinical behavior and a high metastatic potential in ChS. This review will provide an insight into the ChS microenvironment, since immunotherapy and antiangiogenic agents are emerging as interesting therapeutic options for ChS patients.

MiR-6839-5p inhibits cell proliferation, migration and invasion; a possible correlation with the suppressing VEGFA expression in human chondrosarcoma cells

MicroRNAs play an important role in the proliferation, invasion, and metastasis of malignancy. In previous studies (detailed in our previous paper), the expression of miR-6839-5p was significantly increased in SW1353 cells after 125I seed 6 Gy irradiation, which indicated miR-6839-5p may play a tumor suppression function in chondrosarcoma cells. This study aimed to identify the effects of miR-6839-5p on the human chondrosarcoma cells, and investigate the potential target genes of miR-6839-5p. Firstly, chondrosarcoma cells (SW1353 and CAL78) were transfected with hsa-miR-6839-5p specific mimic. Secondly, Cell viability assay (MTT assay), Colony formation assay, Wound healing assay, Transwell assay, TUNEL staining and Western blotting experiments were performed, and the results proved miR-6839-5p can inhibit chondrosarcoma cells proliferation, migration and invasion. Meanwhile, miR-6839-5p significantly down-regulated apoptosis facilitator Bcl-2 expression, and promoted apoptosis of chondrosarcoma cells. It is reasonable to speculate miR-6839-5p might downregulate Bcl-2 expression to induce apoptosis in SW1353 human chondrosarcoma cells. Lastly, RNA extraction and bioinformatic analysis was performed on SW1353 cells transfected with hsa-miR-6839-5p specific mimic to investigate the potential target genes of miR-6839-5p. A total of 253 differentially expressed mRNA genes (105 up-regulated genes and 148 down-regulated genes) were found, and 23 differentially expressed downregulated genes were identified. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to validate the results, which demonstrated the expression of BST2, VEGFA, FPR3 and PPARA was significantly downregulated by miR-6839-5p mimic. Furthermore, miR-6839-5p inhibitor can restore or partially restore the expression value of the above four genes. The analysis results of miRNA target gene prediction database indicated VEGFA was the most likely direct target gene of miR-6839-5p.

New advances in the treatment of chondrosarcoma under the PD-1/PD-L1 pathway

ABSTRACT

Bone sarcomas encompass a group of spontaneous mesenchymal malignancies, among which osteosarcoma, Ewing sarcoma, chondrosarcoma, and chordoma are the most common subtypes. Chondrosarcoma, a relatively prevalent malignant bone tumor that originates from chondrocytes, is characterized by endogenous cartilage ossification within the tumor tissue. Despite the use of aggressive treatment approaches involving extensive surgical resection, chemotherapy, and radiotherapy for patients with osteosarcoma, chondrosarcoma, and chordoma, limited improvements in patient outcomes have been observed. Furthermore, resistance to chemotherapy and radiation therapy has been observed in chondrosarcoma and chordoma cases. Consequently, novel therapeutic approaches for bone sarcomas, including chondrosarcoma, need to be uncovered. Recently, the emergence of immunotherapy and immune checkpoint inhibitors has garnered attention given their clinical success in various diverse types of cancer, thereby prompting investigations into their potential for managing chondrosarcoma. Considering that circumvention of immune surveillance is considered a key factor in the malignant progression of tumors and that immune checkpoints play an important role in modulating antitumor immune effects, blockers or inhibitors targeting these immune checkpoints have become effective therapeutic tools for patients with tumors. One such checkpoint receptor implicated in this process is programmed cell death protein-1 (PD-1). The association between PD-1 and programmed cell death ligand-1 (PD-L1) and cancer progression in humans has been extensively studied, highlighting their remarkable potential as biomarkers for cancer treatment. This review comprehensively examines available studies on current chondrosarcoma treatments and advancements in anti-PD-1/PD-L1 blockade therapy for chondrosarcoma.

A cellular regulator of the niche: telocyte

Interstitial cells are present in the environment of stem cells in order to increase stem cell proliferation and differentiation and they are important to increase the efficiency of their transplantation. Telocytes (TCs) play an important role both in the preservation of tissue organ integrity and in the pathophysiology of many diseases, especially cancer. They make homo- or heterocellular contacts to form the structure of 3D network through their telopodes and deliver signaling molecules via a juxtacrine and/or paracrine association by budding shed vesicles into the vascular, nervous and endocrine systems. During this interaction, along with organelles, mRNA, microRNA, long non-coding RNA, and genomic DNA are transferred. This review article not only specifies the properties of TCs and their roles in the tissue organ microenvironment but also gives information about the factors that play a role in the transport of epigenetic information by TCs.

Visfatin upregulates VEGF-C expression and lymphangiogenesis in esophageal cancer by activating MEK1/2-ERK and NF-κB signaling

Lymph node metastasis is a recognized prognostic factor in esophageal cancer. Adipokines, including visfatin, and the molecule vascular endothelial growth factor (VEGF)-C, are implicated in lymphangiogenesis, but whether any association exists between esophageal cancer, adipokines and VEGF-C is unknown. We examined the relevance of adipokines and VEGF-C in esophageal squamous cell carcinoma (ESCC) in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. We found significantly higher levels of visfatin and VEGF-C expression in esophageal cancer tissue than in normal tissue. Immunohistochemistry (IHC) staining identified that higher levels of visfatin and VEGF-C expression were correlated with advanced stage ESCC. Visfatin treatment of ESCC cell lines upregulated VEGF-C expression and VEGF-C-dependent lymphangiogenesis in lymphatic endothelial cells. Visfatin induced increases in VEGF-C expression by activating the mitogen-activated protein kinase kinases1/2-extracellular signal-regulated kinase (MEK1/2-ERK) and Nuclear Factor Kappa B (NF-κB) signaling cascades. Transfecting ESCC cells with MEK1/2-ERK and NF-κB inhibitors (PD98059, FR180204, PDTC, and TPCK) and siRNAs inhibited visfatin-induced increases in VEGF-C expression. It appears that visfatin and VEGF-C are promising therapeutic targets in the inhibition of lymphangiogenesis in esophageal cancer.

Leptin-VEGF crosstalk in excess body mass and related disorders: A systematic review

By 2030, it is expected that a billion people will have suffer from obesity. Adipose tissue synthesizes leptin, an adipokine that affects cardiovascular risk. Leptin intensifies the synthesis of vascular endothelial growth factor (VEGF). Our study reviews recent reports on leptin-VEGF crosstalk in obesity and related disorders. PubMed, Web of Science, Scopus, and Google Scholar were searched. One hundred and one articles involving human, animal, and in vitro research were included. In vitro studies show the crucial role of interaction between endothelial cells and adipocytes and hypoxia as a factor that intensifies leptin's effects on VEGF. Leptin-VEGF crosstalk promotes the progression of cancer. The animal research reveal that a high-fat diet enhances leptin and VEGF crosstalk. Genetic and epigenetic mechanisms and procreator-offspring programming may be involved in leptin-VEGF crosstalk. Some female-specific characteristics of leptin-VEGF relation in obesity were observed. The human studies have shown that increased leptin and VEGF synthesis and leptin-VEGF crosstalk are factors linking obesity with elevated cardiovascular risk. The studies of the last 10 years documented a range of significant aspects of leptin-VEGF crosstalk specific for obesity and related disorders, shedding new light on the link between obesity and increased cardiovascular risk.

Recent Advances in the Knowledge of the Mechanisms of Leptin Physiology and Actions in Neurological and Metabolic Pathologies

Excess body weight is frequently associated with low-grade inflammation. Evidence indicates a relationship between obesity and cancer, as well as with other diseases, such as diabetes and non-alcoholic fatty liver disease, in which inflammation and the actions of various adipokines play a role in the pathological mechanisms involved in these disorders. Leptin is mainly produced by adipose tissue in proportion to fat stores, but it is also synthesized in other organs, where leptin receptors are expressed. This hormone performs numerous actions in the brain, mainly related to the control of energy homeostasis. It is also involved in neurogenesis and neuroprotection, and central leptin resistance is related to some neurological disorders, e.g., Parkinson's and Alzheimer's diseases. In peripheral tissues, leptin is implicated in the regulation of metabolism, as well as of bone density and muscle mass. All these actions can be affected by changes in leptin levels and the mechanisms associated with resistance to this hormone. This review will present recent advances in the molecular mechanisms of leptin action and their underlying roles in pathological situations, which may be of interest for revealing new approaches for the treatment of diseases where the actions of this adipokine might be compromised.

Visfatin-Induced Inhibition of miR-1264 Facilitates PDGF-C Synthesis in Chondrosarcoma Cells and Enhances Endothelial Progenitor Cell Angiogenesis

New treatments for chondrosarcoma are extremely important. Chondrosarcoma is a primary malignant bone tumor with a very unfavorable prognosis. High-grade chondrosarcoma has a high potential to metastasize to any organ in the body. Platelet-derived growth factor (PDGF) is a potent angiogenic factor that promotes tumor angiogenesis and metastasis. The adipocytokine visfatin promotes metastatic potential of chondrosarcoma; however, the role of visfatin in angiogenesis in human chondrosarcoma is unclear. We report that the levels of PDGF-C expression were positively correlated with tumor stages, significantly higher than the levels of expression in normal cartilage. Visfatin increased PDGF-C expression and endothelial progenitor cell (EPC) angiogenesis through the PI3K/Akt/mTOR signaling pathway, and dose-dependently down-regulated the synthesis of miR-1264, which targets the 3′-UTR of PDGF-C. Additionally, we discovered inhibition of visfatin or PDGF-C in chondrosarcoma tumors significantly reduced tumor angiogenesis and size. Our results indicate that visfatin inhibits miR-1264 production through the PI3K/Akt/mTOR signaling cascade, and thereby promotes PDGF-C expression and chondrosarcoma angiogenesis. Visfatin may be worth targeting in the treatment of chondrosarcoma angiogenesis.

Functional and clinical characteristics of focal adhesion kinases in cancer progression

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase and an adaptor protein that primarily regulates adhesion signaling and cell migration. FAK promotes cell survival in response to stress. Increasing evidence has shown that at the pathological level, FAK is highly expressed in multiple tumors in several systems (including lung, liver, gastric, and colorectal cancers) and correlates with tumor aggressiveness and patient prognosis. At the molecular level, FAK promotes tumor progression mainly by altering survival signals, invasive capacity, epithelial-mesenchymal transition, the tumor microenvironment, the Warburg effect, and stemness of tumor cells. Many effective drugs have been developed based on the comprehensive role of FAK in tumor cells. In addition, its potential as a tumor marker cannot be ignored. Here, we discuss the pathological and pre-clinical evidence of the role of FAK in cancer development; we hope that these findings will assist in FAK-based clinical studies.

Obesity: a perfect storm for carcinogenesis

Obesity-related cancers account for 40% of the cancer cases observed in the USA and obesity is overtaking smoking as the most widespread modifiable risk factor for carcinogenesis. Here, we use the hallmarks of cancer framework to delineate how obesity might influence the carcinogenic hallmarks in somatic cells. We discuss the effects of obesity on (a) sustaining proliferative signaling; (b) evading growth suppressors; (c) resisting cell death; (d) enabling replicative immortality; (e) inducing angiogenesis; (f) activating invasion and metastasis; (g) reprogramming energy metabolism; and (h) avoiding immune destruction, together with its effects on genome instability and tumour-promoting inflammation. We present the current understanding and controversies in this evolving field, and highlight some areas in need of further cross-disciplinary focus. For instance, the relative importance of the many potentially causative obesity-related factors is unclear for each type of malignancy. Even within a single tumour type, it is currently unknown whether one obesity-related factor consistently plays a predominant role, or if this varies between patients or, even in a single patient with time. Clarifying how the hallmarks are affected by obesity may lead to novel prevention and treatment strategies for the increasingly obese population.

Cardiac rehabilitation may influence leptin and VEGF A crosstalk in patients after acute coronary syndrome

Leptin, a well-proven cardiovascular risk factor, influences vascular endothelial growth factor A (VEGF A) synthesis via hypoxia-inducible factor 1 alpha (HIF-1A), nuclear factor kappa-light-chain-enhancer of activated B cells (NfkB) and NILCO (Notch, interleukin 1 [IL1] and leptin cross-talk outcome) pathways. This study aimed to investigate the influence of cardiac rehabilitation (CR) on HIF-1A, NfkB and NILCO dependent leptin and VEGF A cross-talk in patients after acute coronary syndrome (ACS). Fifty post-ACS patients underwent a 2-week CR programme (study group S) and were compared to 50 post-ACS subjects who did not undergo CR (control group K). In group S, at baseline and at completion and in group K once, anthropometric, body composition, blood pressure and heart rate measurements were taken and blood sampling was performed. Serum levels of leptin, VEGF A, VEGF receptor 2 (VEGF R2), HIF-1A, NfkB, interleukin 1-alpha (IL1-alpha) and Notch 1 were determined. In group S, serum VEGF A levels increased while leptin, HIF-1A and VEGF R2 levels decreased and completion but not baseline serum leptin correlated positively with serum VEGF A. Also, serum completion VEGF A correlated positively with NfkB and HIF-1A in group S. Correlation analysis in group S confirmed the significant role of the NILCO pathway in the regulation of VEGF A serum levels mediated by HIF-1A and NfkB. CR may induce the predomination of the NILCO pathway interacting with HIF-1A and NfkB over leptin canonical and non-canonical signalling pathways in the leptin influence on VEGF A in post-ACS patients.Trial registration: ClinicalTrials.gov ID: NCT03935438. The CARDIO-REH randomised study.

Assessment of the RANTES Level Correlation and Selected Inflammatory and Pro-Angiogenic Molecules Evaluation of Their Influence on CRC Clinical Features: A Preliminary Observational Study

Background and Objectives: Assessment of RANTES level and concentrations of inflammatory cytokines: programmed death ligand 1 (PD-L1), interferon gamma IFN-γ, tumor necrosis factor alpha (TNF-α), transforming growht factor β (TGF-β) (and angiogenesis factors: vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor C (VEGF C) in tumor and margin tissues of colorectal cancer (CRC,) and evaluation of RANTES influence on histopathological parameters (microvessel density (MVD), budding, tumor-infiltrating lymphocytes (TILs)), in relation to patients’ clinical features. Materials and Methods: The study used 49 samples of tumor and margin tissues derived from CRC patients. To determinate the concentration of RANTES, PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C, we used the commercially available enzyme-linked immunosorbent assay kit. Additionally, RANTES and PD-L1 expression was assessed with the use of IHC staining in both tumor cells and TILS in randomly selected cases. MVD was assessed on CD34-stained specimens. The MVD and budding were assessed using a light microscope. Results: We found significantly higher levels of RANTES, PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C in the tumor in comparison with the margin. The RANTES tumor levels correlated significantly with those of PD-L1, TNF-α, TGF-β, VEGF-A, and VEGF-C. The RANTES margin levels were significantly associated with the margin levels of all proteins investigated—PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C. Additionally, we observed RANTES- and PD-L1-positive immunostaining in TILs. In a group of 24 specimens, 6 different CRC tumors were positive for RANTES and PD-L1 immunostaining. The IFN-gamma concentration in both tumor and margin and TGF-β in tumor correlated with TILs. TILs were negatively associated with the patients’ disease stage and N parameter. Conclusions: RANTES activity might be associated with angiogenesis, lymphogenesis, and immune escape in CRC. RANTES is an important chemokine that is a part of the chemokine–cytokine network involved in the modulation of TME composition in CRC. Further research may verify which processes are responsible for the associations observed in the study.

The Adipokine Component in the Molecular Regulation of Cancer Cell Survival, Proliferation and Metastasis

A hormonal imbalance may disrupt the rigorously monitored cellular microenvironment by hampering the natural homeostatic mechanisms. The most common example of such hormonal glitch could be seen in obesity where the uprise in adipokine levels is in virtue of the expanding bulk of adipose tissue. Such aberrant endocrine signaling disrupts the regulation of cellular fate, rendering the cells to live in a tumor supportive microenvironment. Previously, it was believed that the adipokines support cancer proliferation and metastasis with no direct involvement in neoplastic transformations and tumorigenesis. However, the recent studies have reported discrete mechanisms that establish the direct involvement of adipokine signaling in tumorigenesis. Moreover, the individual adipokine profile of the patients has never been considered in the prognosis and staging of the disease. Hence, the present manuscript has focused on the reported extensive mechanisms that culminate the basis of poor prognosis and diminished survival rate in obese cancer patients.

The lymphatic vasculature: An active and dynamic player in cancer progression

The lymphatic vasculature has been widely described and explored for its key functions in fluid homeostasis and in the organization and modulation of the immune response. Besides transporting immune cells, lymphatic vessels play relevant roles in tumor growth and tumor cell dissemination. Cancer cells that have invaded into afferent lymphatics are propagated to tumor‐draining lymph nodes (LNs), which represent an important hub for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites. In recent years many studies have reported new mechanisms by which the lymphatic vasculature affects cancer progression, ranging from induction of lymphangiogenesis to metastatic niche preconditioning or immune modulation. In this review, we provide an up‐to‐date description of lymphatic organization and function in peripheral tissues and in LNs and the changes induced to this system by tumor growth and progression. We will specifically focus on the reported interactions that occur between tumor cells and lymphatic endothelial cells (LECs), as well as on interactions between immune cells and LECs, both in the tumor microenvironment and in tumor‐draining LNs. Moreover, the most recent prognostic and therapeutic implications of lymphatics in cancer will be reported and discussed in light of the new immune‐modulatory roles that have been ascribed to LECs.

Investigating lymphangiogenesis in vitro and in vivo using engineered human lymphatic vessel networks

Lymphatic vessel networks are important for various biological processes; thus, incorporating them into engineered constructs can have both research and clinical implications. Engineered lymphatic vessels can improve biomimicry and functionality of in vitro tissue assays and serve as a treatment for various diseases associated with impaired lymphatic function. In this work, we created functional engineered lymphatic vessels that anastomosed to the host lymphatic system postimplantation. We investigated the effect of supporting cells, cell-secreted extracellular matrix, and mechanical forces on lymphatic vessel formation within engineered constructs. Interestingly, lymphatic vasculature responded differently to cyclic stretch compared to blood vasculature. This phenomenon opens up an avenue for investigating the variability of cellular responses to mechanical stimulation.

The lymphatic system is involved in various biological processes, including fluid transport from the interstitium into the venous circulation, lipid absorption, and immune cell trafficking. Despite its critical role in homeostasis, lymphangiogenesis (lymphatic vessel formation) is less widely studied than its counterpart, angiogenesis (blood vessel formation). Although the incorporation of lymphatic vasculature in engineered tissues or organoids would enable more precise mimicry of native tissue, few studies have focused on creating engineered tissues containing lymphatic vessels. Here, we populated thick collagen sheets with human lymphatic endothelial cells, combined with supporting cells and blood endothelial cells, and examined lymphangiogenesis within the resulting constructs. Our model required just a few days to develop a functional lymphatic vessel network, in contrast to other reported models requiring several weeks. Coculture of lymphatic endothelial cells with the appropriate supporting cells and intact PDGFR-β signaling proved essential for the lymphangiogenesis process. Additionally, subjecting the constructs to cyclic stretch enabled the creation of complex muscle tissue aligned with the lymphatic and blood vessel networks, more precisely biomimicking native tissue. Interestingly, the response of developing lymphatic vessels to tensile forces was different from that of blood vessels; while blood vessels oriented perpendicularly to the stretch direction, lymphatic vessels mostly oriented in parallel to the stretch direction. Implantation of the engineered lymphatic constructs into a mouse abdominal wall muscle resulted in anastomosis between host and implant lymphatic vasculatures, demonstrating the engineered construct's potential functionality in vivo. Overall, this model provides a potential platform for investigating lymphangiogenesis and lymphatic disease mechanisms.

Differential expression of angiogenesis markers HSP70, HSP90, VEGF and pERK1/2 in both components of dedifferentiated chondrosarcomas

Dedifferentiated chondrosarcomas (DDCS) are highly malignant bimorphic mesenchymal tumors with poor outcome and limited treatment options. Genes and proteins involved in angiogenesis play an important role in the development of invasion and metastasis. Immunohistochemical stains targeting HSP70, pERK1/2 and VEGFA were applied to a TMA containing 29 DDCS cases representing both tumor components. Higher expression of HSP70 and pERK1/2 was noted in the dedifferentiated component. RNA sequencing performed in 8 paired cases of DDCS comparing well differentiated and dedifferentiated components, showed higher expression of several HSP70 family members and HSP90 in the dedifferentiated component. Furthermore, high mobility group AT-hook 2 (HMAG2) and SET nuclear proto-oncogene demonstrated higher expression in the dedifferentiated component. Thus, the well differentiated and dedifferentiated components of DDCS are different, histologically and transcriptomically. The dedifferentiated component of DDCS shows higher expression of markers that are associated with malignant behavior. Some of these may represent future treatment targets.

Post-Transcriptional Regulation of Gnrhr: A Checkpoint for Metabolic Control of Female Reproduction

The proper expression of gonadotropin-releasing hormone receptors (GnRHRs) by pituitary gonadotropes is critical for maintaining maximum reproductive capacity. GnRH receptor expression must be tightly regulated in order to maintain the normal pattern of expression through the estrous cycle in rodents, which is believed to be important for interpreting the finely tuned pulses of GnRH from the hypothalamus. Much work has shown that Gnrhr expression is heavily regulated at the level of transcription. However, researchers have also discovered that Gnrhr is regulated post-transcriptionally. This review will discuss how RNA-binding proteins and microRNAs may play critical roles in the regulation of GnRHR expression. We will also discuss how these post-transcriptional regulators may themselves be affected by metabolic cues, specifically with regards to the adipokine leptin. All together, we present evidence that Gnrhr is regulated post-transcriptionally, and that this concept must be further explored in order to fully understand the complex nature of this receptor.

Leptin and Cancer: Updated Functional Roles in Carcinogenesis, Therapeutic Niches, and Developments

Leptin is an obesity-associated adipokine that is known to regulate energy metabolism and reproduction and to control appetite via the leptin receptor. Recent work has identified specific cell types other than adipocytes that harbor leptin and leptin receptor expression, particularly in cancers and tumor microenvironments, and characterized the role of this signaling axis in cancer progression. Furthermore, the prognostic significance of leptin in various types of cancer and the ability to noninvasively detect leptin levels in serum samples have attracted attention for potential clinical applications. Emerging findings have demonstrated the direct and indirect biological effects of leptin in regulating cancer proliferation, metastasis, angiogenesis and chemoresistance, warranting the exploration of the underlying molecular mechanisms to develop a novel therapeutic strategy. In this review article, we summarize and integrate transcriptome and clinical data from cancer patients together with the recent findings related to the leptin signaling axis in the aforementioned malignant phenotypes. In addition, a comprehensive analysis of leptin and leptin receptor distribution in a pancancer panel and in individual cell types of specific organs at the single-cell level is presented, identifying those sites that are prone to leptin-mediated tumorigenesis. Our results shed light on the role of leptin in cancer and provide guidance and potential directions for further research for scientists in this field.

The Roles of Non-Coding RNAs in Tumor-Associated Lymphangiogenesis

Simple Summary

The lymphatic system plays key roles in the bodies’ defence against disease, including cancer. The expansion of this system is termed lymphangiogenesis and it is orchestrated by factors and conditions within the microenvironment. One approach to prevent cancer progression is by interfering with these microenvironment factors that promote this process and that facilitate the spread of cancer cells to distant organs. One of these factors are non-coding RNAs. This review will summarize recent findings of the distinct roles played by non-coding RNAs in the lymphatic system within normal tissues and tumours. Understanding the mechanisms involved in this process can provide new avenues for therapeutic intervention for inhibiting the spread of cancer.

Abstract

Lymphatic vessels are regarded as the ”forgotten” circulation. Despite this, growing evidence has shown significant roles for the lymphatic circulation in normal and pathological conditions in humans, including cancers. The dissemination of tumor cells to other organs is often mediated by lymphatic vessels that serve as a conduit and is often referred to as tumor-associated lymphangiogenesis. Some of the most well-studied lymphangiogenic factors that govern tumor lymphangiogenesis are the vascular endothelial growth factor (VEGF-C/D and VEGFR-2/3), neuroplilin-2 (NRP2), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF), to name a few. However, recent findings have illustrated that non-coding RNAs are significantly involved in regulating gene expression in most biological processes, including lymphangiogenesis. In this review, we focus on the regulation of growth factors and non-coding RNAs (ncRNAs) in the lymphatic development in normal and cancer physiology. Then, we discuss the lymphangiogenic factors that necessitate tumor-associated lymphangiogenesis, with regards to ncRNAs in various types of cancer. Understanding the different roles of ncRNAs in regulating lymphatic vasculature in normal and cancer conditions may pave the way towards the development of ncRNA-based anti-lymphangiogenic therapy.

Increased CXCL12 expression in endometrium of women with abnormal uterine bleeding is post-transcriptionally mediated via miR-23b-3p and is associated with decreased expression of the miR-23b-3p/24-3p/27b-3p cluster: a pilot study

OBJECTIVE

To study C-X-C motif chemokine 12 (CXCL12) and CXCR4 expression in endometrial tissue from both women with and without abnormal uterine bleeding (AUB) of endometrial origin and evaluate their relationship with microRNA (miRNA).

DESIGN

Retrospective and laboratory study.

SETTING

University-based research laboratory.

PATIENT(S)

Nine women with and without abnormal uterine bleeding, all of whom were in the secretory stage of their menstrual cycle, who provided endometrial biopsy tissue.

INTERVENTION(S)

Immunohistochemical localization of CXCL12 and CXCR4 as well as quantitative reverse-transcription polymerase chain reaction (qRT-PCR) assessment of mRNA expression in archived endometrial biopsy tissue and in vitro cell culture using the immortalized endometrial stromal cell line, t-HESC. Endometrial stromal cell line, t-HESC transfection with nontargeting, negative control miRNA mimics or miRNA mimics for miR-23b-3p and mRNA assessment miR-23b-3p expression confirmed by qRT-PCR and evaluation of impact on CXCL12 expression at the protein level by enzyme-linked immunosorbent assay and mRNA levels by qRT-PCR.

MAIN OUTCOME MEASURE(S)

Expression of CXCL12 and CXCR4 protein via immunohistochemistry and mRNA and miRNA levels of CXCL12 and CXCR4 as well as miR-23b-3p, miR-24b-3p, and miR-27b-3p, respectively, via qRT-PCR.

RESULT(S)

CXCL12 and its receptor CXCR4 expression were up-regulated in the endometrial tissue of women with AUB at the protein level, but this up-regulation of expression was only associated with increased CXCR4 mRNA expression. To evaluate whether CXCL12 may be post-transcriptionally regulated, we assessed expression of miR-23b-3p, a bona fide post-transcriptional regulator of CXCL12 expression. The expression of miR-23b-3p was statistically significantly lower in AUB endometrial tissue, as were fellow cluster members miR-24-3p and miR-27-3p. Transfection of t-HESC cells with pre-miR-23b-3p mimics statistically significantly reduced the levels of CXCL12 secreted protein but not mRNA levels, suggesting that miR-23b-3p retards protein translation independent of transcript degradation.

CONCLUSION(S)

Reduced expression of the miR-23b-3p/24-3p/27b-3p cluster is associated with elevated expression of CXCL12, which may contribute to the pathophysiology of AUB.

Association of rs699947 (-2578 C/A) and rs2010963 (-634 G/C) Single Nucleotide Polymorphisms of the VEGF Gene, VEGF-A and Leptin Serum Level, and Cardiovascular Risk in Patients with Excess Body Mass: A Case-Control Study

Background: Two single nucleotide polymorphisms (SNPs) of the VEGF gene, rs699947 and rs2010963, are responsible for differentiated gene expression. A mutual dependence between VEGF and leptin serum level has been observed. This study investigated the associations between the rs699947 and rs2010963 SNPs of VEGF gene, VEGF-A, and leptin serum concentrations, and cardiometabolic risk of body mass excess. Methods: In this case–control study, 212 subjects with excess body mass and 145 normal-weight controls gave blood samples and underwent anthropometric and pulse wave analysis. Genotyping of VEGF gene was carried out to analyze the rs699947 (−2578 C/A) and rs2010963 (−634 G/C) SNPs. (ClinicalTrials.gov ID: NCT04077554). Results: This study showed a significant positive correlation between serum levels of VEGF-A and leptin in individuals with excess body mass possessing the CC genotype of the rs699947 variant of the VEGF gene. It has been registered that an increase in VEGF-A serum level correlates with an increase in arterial stiffness in excess body mass patients harboring AA genotype of the rs699947 (−2578 C/A) variant of the VEGF gene. No differences in VEGF-A and leptin serum concentrations were noted between particular genotypes. Conclusions: The CC genotype of the rs699947 variant of the VEGF gene promotes a positive interdependency between leptin and VEGF-A serum levels in subjects with excess body mass.

WISP-1 Promotes Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma Cells Via the miR-153-3p/Snail Axis

Around half of all patients with oral squamous cell carcinoma (OSCC) present with lymphatic metastasis, a strong predictor of poor survival. Improving survival rates depends on preventing the first step in the “invasion-metastasis cascade,” epithelial-to-mesenchymal transition (EMT), and developing antilymphangiogenesis therapies that antagonize lymphatic metastasis. The extracellular matrix-related protein WISP-1 (WNT1-inducible signaling pathway protein-1) stimulates bone remodeling and tumor progression. We have previously reported that WISP-1 promotes OSCC cell migration and lymphangiogenesis induced by vascular endothelial growth factor C (VEGF-C). This investigation sought to determine the role of WISP-1 in regulating EMT in OSCC. Our analysis of oral cancer data from The Cancer Genome Atlas (TCGA) database revealed significant and positive associations between levels of WISP-1 expression and clinical disease stage, as well as regional lymph node metastasis. We also found higher levels of WISP-1 expression in serum samples obtained from patients with OSCC compared with samples from healthy controls. In a series of in vitro investigations, WISP-1 activated EMT signaling via the FAK/ILK/Akt and Snail signaling transduction pathways and downregulated miR-153-3p expression in OSCC cells. Our findings detail how WISP-1 promotes EMT via the miR-153-3p/Snail axis in OSCC cells.

Long Noncoding RNA ASLNC07322 Functions in VEGF-C Expression Regulated by Smad4 during Colon Cancer Metastasis

Deletion and mutation of the Smad4 gene are favorable events for the progression of colon cancer, which is related to the negative regulation of vascular endothelial growth factor C (VEGF-C). However, the regulatory mechanism between Smad4 and VEGF-C remains unclear. We reported first that Smad4 can increase the transcription of miR-128-3p, a microRNA targeting VEGF-C mRNA, resulting in a negative correlation between Smad4 and VEGF-C. Moreover, we found that Smad4 combined with Smad3 can positively regulate VEGF-C during colon cancer metastasis through binding to VEGF-C gene promoter. Further, results revealed a mechanism that long noncoding RNA (lncRNA) ASLNC07322 increased specifically in metastatic colon cancer and decreased miR-128-3p as a sponge, leading to a subsequent elevation of VEGF-C. In a word, there are two pathways in the progression of colon cancer, including Smad4/miR-128-3p/VEGF-C and Smad4/VEGF-C pathways in non-metastatic and metastatic colon cancer, respectively. ASLNC07322 crucially controlled this negative and positive regulatory transformation between them. Additionally, ASLNC07322 knockdown combined with Smad4 overexpression could efficiently inhibit lymphatic endothelial cells (LECs) proliferation and tube formation in vitro, as well as tumor growth and lymphangiogenesis in vivo. These data explained the underlying mechanism of Smad4 contribution on VEGF-C expression during metastasis where ASLNC07322 functions vitally as a switch in colon cancer.

Non-coding RNAs as Regulators of Lymphangiogenesis in Lymphatic Development, Inflammation, and Cancer Metastasis

Non-coding RNAs (ncRNAs), which do not encode proteins, have pivotal roles in manipulating gene expression in development, physiology, and pathology. Emerging data have shown that ncRNAs can regulate lymphangiogenesis, which refers to lymphatics deriving from preexisting vessels, becomes established during embryogenesis, and has a close relationship with pathological conditions such as lymphatic developmental diseases, inflammation, and cancer. This review summarizes the molecular mechanisms of lymphangiogenesis in lymphatic development, inflammation and cancer metastasis, and discusses ncRNAs' regulatory effects on them. Therapeutic targets with regard to lymphangiogenesis are also discussed.

An update on current and future treatment options for chondrosarcoma

Introduction: Human chondrosarcomas (CS; a malignant cartilage-forming bone tumor) respond poorly to chemotherapy and radiation treatment, resulting in high morbidity and mortality rates. Expanded treatment options are urgently needed. Areas covered: This article updates our 2014 review, in which we evaluated the CS treatments available at that time and potential treatment options under investigation. Since then, advances in research findings, particularly from Chinese herbal medicines, may be bringing us closer to more effective therapies for CS. In particular, promising findings have been reported from research targeting platelet-derived growth factor receptor. Expert opinion: Few treatment options exist for CS; chemotherapy is not even an option for unresectable disease, in which 5-year survival rates are just 2%. New information about the multitude of genes and signaling pathways that encourage CS growth, invasion and metastasis are clarifying how certain signaling pathways and plant-derived active compounds, especially molecularly-targeted therapies that inhibit the PDGF receptor, interfering with these biological processes. This review summarizes discoveries from the last 5 years and discusses how these findings are fueling ongoing work into effectively dealing with the disease process and improving the treatment of CS.

Molecular Insight into the Interaction between Epigenetics and Leptin in Metabolic Disorders

Nowadays, it is well-known that the deregulation of epigenetic machinery is a common biological event leading to the development and progression of metabolic disorders. Moreover, the expression level and actions of leptin, a vast adipocytokine regulating energy metabolism, appear to be strongly associated with epigenetics. Therefore, the aim of this review was to summarize the current knowledge of the epigenetic regulation of leptin as well as the leptin-induced epigenetic modifications in metabolic disorders and associated phenomena. The collected data indicated that the deregulation of leptin expression and secretion that occurs during the course of metabolic diseases is underlain by a variation in the level of promoter methylation, the occurrence of histone modifications, along with miRNA interference. Furthermore, leptin was proven to epigenetically regulate several miRNAs and affect the activity of the histone deacetylases. These epigenetic modifications were observed in obesity, gestational diabetes, metabolic syndrome and concerned various molecular processes like glucose metabolism, insulin sensitivity, liver fibrosis, obesity-related carcinogenesis, adipogenesis or fetal/early postnatal programming. Moreover, the circulating miRNA profiles were associated with the plasma leptin level in metabolic syndrome, and miRNAs were found to be involved in hypothalamic leptin sensitivity. In summary, the evidence suggests that leptin is both a target and a mediator of epigenetic changes that develop in numerous tissues during metabolic disorders.

An Insight into the Roles of MicroRNAs and Exosomes in Sarcoma

Sarcomas are rare solid tumors, but at least one-third of patients with sarcoma die from tumor-related disease. MicroRNA (miRNA) is a noncoding RNA that regulates gene expression in all cells and plays a key role in the progression of cancers. Recently, it was identified that miRNAs are transferred between cells by enclosure in extracellular vesicles, especially exosomes. The exosome is a 100 nm-sized membraned vesicle that is secreted by many kinds of cells and contains miRNA, mRNA, DNA, and proteins. Cancer uses exosomes to influence not only the tumor microenvironment but also the distant organ to create a premetastatic niche. The progression of sarcoma is also regulated by miRNAs and exosomes. These miRNAs and exosomes can be targeted as biomarkers and treatments. In this review, we summarize the studies of miRNA and exosomes in sarcoma.

Adipokines Regulate the Expression of Tumor-Relevant MicroRNAs

BACKGROUND

Increasing prevalence of obesity requires the investigation of respective comorbidities, including tumor diseases like colorectal, renal, post-menopausal breast, prostate cancer, and leukemia. To date, molecular mechanisms of the malignant transformation of these peripheral tissues induced by obesity remain unclear. Adipose tissue secretes factors with hormone-like functions, the adipokines, and is therefore categorized as an endocrine organ. Current research demonstrates the ability of adipose tissue to alter DNA methylation and gene expression in peripheral tissues, probably affecting microRNA (miR) expression.

METHODS

Literature was analyzed for adipokine-regulated miRs. Many of these adipokine upregulated or downregulated miRs exert either oncogenic or anti-tumoral potential.

RESULTS

The three selected and analyzed adipokines, adiponectin, leptin, and resistin, induce more strongly oncogenic miRs and simultaneously reduce anti-tumoral miRs than vice versa. This effect is not only true for the pure number of regulated miRs, it is also the case by consideration of the abundance of the respective miR expression based on actual data sets derived from next-generation sequencing.

CONCLUSION

The link of obesity and cancer is analyzed under the aspect of adipokine-regulated miRs. At the same time the impact of miR abundance is considered as a regulatory variable. This context offers new strategies for tumor therapy and diagnostics.

Vascular endothelial growth factor-C promotes human mesenchymal stem cell migration via an ERK-and FAK-dependent mechanism

Vascular endothelial cell growth factor-C (VEGF-C) is a member of the VEGF family and plays a role in various biological activities. VEGF-C enhances proliferation and migration of lymphatic endothelial cells and vascular endothelial cells through VEGF receptor 2 (VEGFR2) and/or receptor 3 (VEGFR3), and thereby induces lymphangiogenesis or angiogenesis. However, it remains unclear whether VEGF-C promotes the migration of mesenchymal stem cells (MSCs). Here, we investigated the effects of VEGF-C on the migration of MSCs and evaluated the underlying molecular mechanisms. VEGF-C treatment significantly induced the migration of MSCs, which is accompanied by the promotion of actin cytoskeletal reorganization and focal adhesion assembly. VEGF-C treatment enhanced the phosphorylation of VEGFR2 and VEGFR3 proteins in MSCs, and pretreatment with VEGFR2 and VEGFR3 kinase inhibitors effectively suppressed the VEGF-C-induced MSC migration. In addition, VEGF-C treatment promoted phosphorylation of ERK and FAK proteins in MSCs, and inhibition of VEGFR2 and VEGFR3 signaling pathways abolished the VEGF-C-induced activation of ERK and FAK proteins. Furthermore, treatment with ERK and FAK inhibitors suppressed VEGF-C-induced actin cytoskeletal reorganization and focal adhesion assembly, and then significantly inhibited MSCs migration. These results suggest that VEGF-C-induced MSC migration is mediated via VEGFR2 and VEGFR3, and follows the activation of the ERK and FAK signaling pathway. Thus, VEGF-C may be valuable in tissue regeneration and repair in MSC-based therapy.

Leptin signaling axis specifically associates with clinical prognosis and is multifunctional in regulating cancer progression

Leptin is a peptide hormone that has been characterized as the ligand of leptin receptor (LEPR). The observation of leptin secretion and leptin receptor expression beyond the normal tissues suggests the potentially critical roles other than its physiological function. In addition to the original function in controlling appetite and energy expenditure, leptin-mediated signaling axis through leptin receptor is multifunctional which plays role in the regulation toward broad types of cancer. Emerging evidences has indicated leptin's function in promoting several processes which are relevant to cancer progression including cell proliferation, metastasis, angiogenesis and drug resistance. We relatively display leptin and leptin receptor expression levels in pan-cancer panel based on the transcriptome analysis via dataset The Cancer Genome Atlas (TCGA), and show the clinical association of the axis in predicting cancer prognosis. The results indicate the pathological impacts of this axis on many types of cancer. This review mainly focuses on leptin-mediated effects and its downstream signaling related to the progression of cancers, and displays the clinical significance of this axis including the impact on cancer patient survival.

Biomarkers of chondrosarcoma

Clinical outcome prediction is major concern to patients with cancer. Various molecular markers in various carcinomas have been identified in the past few decades. However, accurate predictors in chondrosarcoma have not been developed, even though chondrosarcoma is the second most common primary bone tumour. Chondrosarcoma is the cartilage-forming malignancy and shows a wide spectrum of clinicopathological behaviours. The majority of chondrosarcoma grows slowly and rarely metastasises, and adequate surgery leads to a good prognosis. However, wide surgical excision is acquired in high-grade chondrosarcoma, because this tumour is highly resistant to chemotherapy and radiotherapy. To decide best therapy, accurate diagnostic markers are also necessary in chondrosarcoma. It is reported that angiogenesis and lymphangiogenesis increase by chondrosarcoma staging, and they are promoted by leptin and adiponectin. Several microRNAs to regulate vascular endothelial growth factor (VEGF)-A and VEGF-C are also reported. Alpha-methylacyl-CoA racemase and periostin are proposed as new biomarkers for differential diagnosis of enchondroma and chondrosarcoma. This review summarises that chondrosarcoma diagnostic markers are currently reported.

Hallmarks of Bone Metastasis

Breast cancer bone metastasis develops as the result of a series of complex interactions between tumor cells, bone marrow cells, and resident bone cells. The net effect of these interactions are the disruption of normal bone homeostasis, often with significantly increased osteoclast and osteoblast activity, which has provided a rational target for controlling tumor progression, with little or no emphasis on tumor eradication. Indeed, the clinical course of metastatic breast cancer is relatively long, with patients likely to experience sequential skeletal-related events (SREs), often over lengthy periods of time, even up to decades. These SREs include bone pain, fractures, and spinal cord compression, all of which may profoundly impair a patient's quality-of-life. Our understanding of the contributions of the host bone and bone marrow cells to the control of tumor progression has grown over the years, yet the focus of virtually all available treatments remains on the control of resident bone cells, primarily osteoclasts. In this perspective, our focus is to move away from the current emphasis on the control of bone cells and focus our attention on the hallmarks of bone metastatic tumor cells and how these differ from primary tumor cells and normal host cells. In our opinion, there remains a largely unmet medical need to develop and utilize therapies that impede metastatic tumor cells while sparing normal host bone and bone marrow cells. This perspective examines the impact of metastatic tumor cells on the bone microenvironment and proposes potential new directions for uncovering the important mechanisms driving metastatic progression in bone based on the hallmarks of bone metastasis.

Brain-derived neurotrophic factor promotes VEGF-C-dependent lymphangiogenesis by suppressing miR-624-3p in human chondrosarcoma cells

Chondrosarcoma is the second most common primary malignancy of bone, and one of the most difficult bone tumors to diagnose and treat. It is well known that increased levels of vascular endothelial growth factor-C (VEGF-C) promote active tumor lymphangiogenesis and lymphatic tumor spread to regional lymph nodes. Brain-derived neurotrophic factor (BDNF) is known to promote metastasis in human chondrosarcoma cells. Knowing more about the mechanism of BDNF in VEGF-C expression and lymphangiogenesis in human chondrosarcoma would improve our understanding as how to prevent chondrosarcoma angiogenesis and metastasis, which currently lacks effective adjuvant treatment. Here, we found that BDNF expression was at least 2.5-fold higher in the highly migratory JJ012(S10) cell line as compared with the primordial cell line (JJ012). In addition, VEGF-C expression and secretion was markedly increased in JJ012(S10) cells. Conditioned medium from JJ012(S10) cells significantly promoted migration and tube formation of human lymphatic endothelial cells (LECs), whereas knockdown of BDNF attenuated LEC migration and tube formation by suppressing VEGF-C production in JJ012(S10) cells. Mechanistic investigations indicated that BDNF facilitated VEGF-C-dependent lymphangiogenesis through the MEK/ERK/mTOR signaling pathway. We also showed that microRNA (miR)-624-3p expression was negatively regulated by BDNF via the MEK/ERK/mTOR cascade. Importantly, BDNF knockdown profoundly inhibited tumor-associated lymphangiogenesis in vivo. Further analyses identified that BDNF promoted tumor lymphangiogenesis by downregulating miR-624-3p in human chondrosarcoma tissues. In conclusion, this study is the first to reveal the mechanism underlying BDNF-induced lymphangiogenesis. We suggest that BDNF may serve as a promising therapeutic target for the restriction of VEGF-C-mediated tumor lymphangiogenesis and lymphatic metastasis.

Induction of sirtuin-1 signaling by resveratrol induces human chondrosarcoma cell apoptosis and exhibits antitumor activity

Chondrosarcoma is a malignant primary bone tumor. Sirtuin-1 (SIRT1), which is a member of sirtuin family, plays a dual role either in cancer promotion or suppression. There is no report about the role of SIRT1 in the human chondrosarcoma cells. Resveratrol is a potent activator of SIRT1. However, its effects on chondrosarcoma have not been extensively studied. Here, we investigated the role of SIRT1 induction by resveratrol in human chondrosarcoma cell growth and tumor progression. Resveratrol significantly decreased cell viability and induced cell apoptosis in human chondrosarcoma cells in a dose-dependent manner. The protein expression and activity of SIRT1 were activated after treatment with resveratrol. Resveratrol significantly inhibited NF-κB signaling by deacetylating the p65 subunit of NF-κB complex, which could be reversed by siRNA-SIRT1 transfection or deacetylation inhibitor MS-275. Resveratrol induced-apoptosis involved a caspase-3-mediated mechanism. Both siRNA-SIRT1 transfection and MS-275 significantly inhibited the resveratrol-induced caspase-3 cleavage and activity in human chondrosarcoma cells. Moreover, in vivo chondrosarcoma xenograft study revealed a dramatic reduction in tumor volume and the increased SIRT1 and cleaved caspase-3 expressions in tumors by resveratrol treatment. These results suggest that resveratrol induces chondrosarcoma cell apoptosis via a SIRT1-activated NF-κB deacetylation and exhibits anti-chondrosarcoma activity in vivo.

Leptin accelerates the pathogenesis of heterotopic ossification in rat tendon tissues via mTORC1 signaling

Leptin, an adipocyte-derived cytokine associated with bone metabolism, is believed to play a critical role in the pathogenesis of heterotopic ossification (HO). The effect and underlying action mechanism of leptin were investigated on osteogenic differentiation of tendon-derived stem cells (TDSCs) in vitro and the HO formation in rat tendons. Isolated rat TDSCs were treated with various concentrations of leptin in the presence or absence of mTORC1 signaling specific inhibitor rapamycin in vitro. A rat model with Achilles tenotomy was employed to evaluate the effect of leptin on HO formation together with or without rapamycin treatment. In vitro studies with TDSCs showed that leptin increased the expression of osteogenic biomarkers (alkaline phosphatase, runt-related transcription factor 2, osterix, osteocalcin) and enhanced mineralization of TDSCs via activating the mTORC1 signal pathway (as indicated by phosphorylation of p70 ribosomal S6 kinase 1 and p70 ribosomal S6). However, mTORC1 signaling blockade with rapamycin treatment suppressed leptin-induced osteogenic differentiation and mineralization. In vivo studies showed that leptin promoted HO formation in the Achilles tendon after tenotomy, and rapamycin treatment blocked leptin-induced HO formation. In conclusion, leptin can promote TDSC osteogenic differentiation and heterotopic bone formation via mTORC1 signaling in both vitro and vivo model, which provides a new potential therapeutic target for HO prevention.

YKL-40-Induced Inhibition of miR-590-3p Promotes Interleukin-18 Expression and Angiogenesis of Endothelial Progenitor Cells

YKL-40, also known as human cartilage glycoprotein-39 or chitinase-3-like-1, is a pro-inflammatory protein that is highly expressed in rheumatoid arthritis (RA) patients. Angiogenesis is a critical step in the pathogenesis of RA, promoting the infiltration of inflammatory cells into joints and providing oxygen and nutrients to RA pannus. In this study, we examined the effects of YKL-40 in the production of the pro-inflammatory cytokine interleukin-18 (IL-18), and the stimulation of angiogenesis and accumulation of osteoblasts. We observed that YKL-40 induces IL-18 production in osteoblasts and thereby stimulates angiogenesis of endothelial progenitor cells (EPCs). We found that this process occurs through the suppression of miR-590-3p via the focal adhesion kinase (FAK)/PI3K/Akt signaling pathway. YKL-40 inhibition reduced angiogenesis in in vivo models of angiogenesis: the chick embryo chorioallantoic membrane (CAM) and Matrigel plug models. We report that YKL-40 stimulates IL-18 expression in osteoblasts and facilitates EPC angiogenesis.

Leptin signaling and cancer chemoresistance: Perspectives

Obesity is a major health problem and currently is endemic around the world. Obesity is a risk factor for several different types of cancer, significantly promoting cancer incidence, progression, poor prognosis and resistance to anti-cancer therapies. The study of this resistance is critical as development of chemoresistance is a serious drawback for the successful and effective drug-based treatments of cancer. There is increasing evidence that augmented adiposity can impact on chemotherapeutic treatment of cancer and the development of resistance to these treatments, particularly through one of its signature mediators, the adipokine leptin. Leptin is a pro-inflammatory, pro-angiogenic and pro-tumorigenic adipokine that has been implicated in many cancers promoting processes such as angiogenesis, metastasis, tumorigenesis and survival/resistance to apoptosis. Several possible mechanisms that could potentially be developed by cancer cells to elicit drug resistance have been suggested in the literature. Here, we summarize and discuss the current state of the literature on the role of obesity and leptin on chemoresistance, particularly as it relates to breast and pancreatic cancers. We focus on the role of leptin and its significance in possibly driving these proposed chemoresistance mechanisms, and examine its effects on cancer cell survival signals and expansion of the cancer stem cell sub-populations.

Kuei-Lu-Er-Xian-Jiao extract enhances BMP-2 production in osteoblasts

Osteoporosis is a common skeletal disorder, resulting from an imbalance in bone resorption relative to formation. Bone morphogenetic protein (BMP) is a key regulator in bone formation and osteoblastic differentiation. Hence, compounds that promote BMP expression may be suitable candidates for osteoporosis treatment. This study examined the effects of the traditional Chinese medicinal agent, Kuei-Lu-Er-Xian-Jiao (KLEXJ), on BMP-2 production in osteoblasts. We found that KLEXJ extract promoted osteoblastic differentiation marker ALP activity and increased BMP-2 production; pretreatment with PI3K and Akt inhibitors, or small interfering RNA (siRNA), reduced these effects. KLEXJ also enhanced PI3K and Akt phosphorylation. Treatment of osteoblastic cells with NF-κB inhibitors (TPCK or PDTC) markedly inhibited KLEXJ-enhancement of ALP activity and BMP-2 production. KLEXJ also significantly promoted p65 phosphorylation, while treatment with PI3K and Akt inhibitors antagonized KLEXJ-enhanced p65 phosphorylation. Thus, KLEXJ enhances ALP activity and BMP-2 production of osteoblasts through the PI3K/Akt/ NF-κB signaling pathway and hence may be suitable in the treatment of osteoporosis.