Soluble vascular endothelial growth factor receptor-3 suppresses lymphangiogenesis and lymphatic metastasis in bladder cancer

Stable laminar shear stress induces G1 cell cycle arrest and autophagy in urothelial carcinoma by a torque sensor-coupled cone-and-plate device

The microenvironments of urinary systems play crucial roles in the development and metastasis of cancers due to their generation of complex temporal and spatial fluidic profiles. Because of their versatility in creating desired biomimetic flow, cone-and-plate bioreactors offer great potential for bladder cancer research. In this study, we construct a biocompatible cone-and-plate device coupled with a torque sensor, enabling the application and real-time monitoring of stable shear stress up to 50 dyne/cm². Under a stable shear stress stimulation at 12 dyne/cm2, bladder cancer cell BFTC-905 is arrested at the G1 phase with decreased cell proliferation after 24-hour treatment. This effect is associated with increased cyclin-dependent kinase inhibitors p21 and p27, inhibiting cyclin D1/CDK4 complex with dephosphorylation of serine 608 on the retinoblastoma protein. Consequently, an increase in cyclin D3 and decreases in cyclin A2 and cyclin E2 are observed. Moreover, we demonstrate that the shear stress stimulation upregulates the expression of autophagy-related proteins Beclin-1, LC3B-I and LC3B-II, while caspase cleavages are not activated under the same condition. The design of this system and its application shed new light on flow-induced phenomena in the study of urothelial carcinomas.

Vascular Endothelial Growth Factor C and D Signaling Pathways as Potential Targets for the Treatment of Neovascular Age-Related Macular Degeneration: A Narrative Review

The development of treatments targeting the vascular endothelial growth factor (VEGF) signaling pathways have traditionally been firstly investigated in oncology and then advanced into retinal disease indications. Members of the VEGF family of endogenous ligands and their respective receptors play a central role in vasculogenesis and angiogenesis during both development and physiological homeostasis. They can also play a pathogenic role in cancer and retinal diseases. Therapeutic approaches have mostly focused on targeting VEGF-A signaling; however, research has shown that VEGF-C and VEGF-D signaling pathways are also important to the disease pathogenesis of tumors and retinal diseases. This review highlights the important therapeutic advances and the remaining unmet need for improved therapies targeting additional mechanisms beyond VEGF-A. Additionally, it provides an overview of alternative VEGF-C and VEGF-D signaling involvement in both health and disease, highlighting their key contributions in the multifactorial pathophysiology of retinal disease including neovascular age-related macular degeneration (nAMD). Strategies for targeting VEGF-C/-D signaling pathways will also be reviewed, with an emphasis on agents currently being developed for the treatment of nAMD.

VEGFR-3 signaling in macrophages: friend or foe in disease?

Lymphatic vessels have been increasingly appreciated in the context of immunology not only as passive conduits for immune and cancer cell transport but also as key in local tissue immunomodulation. Targeting lymphatic vessel growth and potential immune regulation often takes advantage of vascular endothelial growth factor receptor-3 (VEGFR-3) signaling to manipulate lymphatic biology. A receptor tyrosine kinase, VEGFR-3, is highly expressed on lymphatic endothelial cells, and its signaling is key in lymphatic growth, development, and survival and, as a result, often considered to be "lymphatic-specific" in adults. A subset of immune cells, notably of the monocyte-derived lineage, have been identified to express VEGFR-3 in tissues from the lung to the gut and in conditions as varied as cancer and chronic kidney disease. These VEGFR-3+ macrophages are highly chemotactic toward the VEGFR-3 ligands VEGF-C and VEGF-D. VEGFR-3 signaling has also been implicated in dictating the plasticity of these cells from pro-inflammatory to anti-inflammatory phenotypes. Conversely, expression may potentially be transient during monocyte differentiation with unknown effects. Macrophages play critically important and varied roles in the onset and resolution of inflammation, tissue remodeling, and vasculogenesis: targeting lymphatic vessel growth and immunomodulation by manipulating VEGFR-3 signaling may thus impact macrophage biology and their impact on disease pathogenesis. This mini review highlights the studies and pathologies in which VEGFR-3+ macrophages have been specifically identified, as well as the activity and polarization changes that macrophage VEGFR-3 signaling may elicit, and affords some conclusions as to the importance of macrophage VEGFR-3 signaling in disease.

Analysis of the Genetic Characteristics and Metastatic Pathways of G1 and G2 Colorectal Neuroendocrine Neoplasms

Objective

G1 and G2 colorectal neuroendocrine neoplasms (NENs) are a group of rare and indolent diseases. We aimed to delineate their genetic characteristics and explore their metastatic mechanisms.

Methods

We used next-generation sequencing technology for targeted sequencing for 54 patients with G1 and G2 colorectal NENs. We delineated their genetic features and compared the genetic characteristics between metastatic NENs and nonmetastatic NENs. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was utilized to explore their abnormal pathways and study their potential metastatic mechanisms.

Results

We collected 23 metastatic NENs and 31 nonmetastatic NENs. In the whole cohort, the common mutated genes were NCOR2, BRD4, MDC1, ARID1A, AXIN2, etc. The common copy number variations (CNVs) included amplification of HIST1H3D, amplification of HIST1H3E, and loss of PTEN. The KEGG enrichment analysis revealed that PI3K-Akt, MAPK, and Rap1 were the major abnormal pathways. There were significantly different genetic features between metastatic NENs and nonmetastatic NENs. The metastatic NENs shared only 47 (22.5%) mutated genes and 6 (13.3%) CNVs with nonmetastatic NENs. NCOR2, BRD4, CDKN1B, CYP3A5, and EIF1AX were the commonly mutated genes in metastatic NENs, while NCOR2, MDC1, AXIN2, PIK3C2G, and PTPRT were the commonly mutated genes in nonmetastatic NENs. Metastatic NENs presented a significantly higher proportion of abnormal pathways of cell senescence (56.5% vs 25.8%, P = .022) and lysine degradation (43.5% vs 16.1%, P = .027) than nonmetastatic NENs.

Conclusion

G1 and G2 colorectal NENs are a group of heterogeneous diseases that might obtain an increased invasive ability through aberrant cell senescence and lysine degradation pathways.

Lymphatic vessel: origin, heterogeneity, biological functions, and therapeutic targets

Lymphatic vessels, comprising the secondary circulatory system in human body, play a multifaceted role in maintaining homeostasis among various tissues and organs. They are tasked with a serious of responsibilities, including the regulation of lymph absorption and transport, the orchestration of immune surveillance and responses. Lymphatic vessel development undergoes a series of sophisticated regulatory signaling pathways governing heterogeneous-origin cell populations stepwise to assemble into the highly specialized lymphatic vessel networks. Lymphangiogenesis, as defined by new lymphatic vessels sprouting from preexisting lymphatic vessels/embryonic veins, is the main developmental mechanism underlying the formation and expansion of lymphatic vessel networks in an embryo. However, abnormal lymphangiogenesis could be observed in many pathological conditions and has a close relationship with the development and progression of various diseases. Mechanistic studies have revealed a set of lymphangiogenic factors and cascades that may serve as the potential targets for regulating abnormal lymphangiogenesis, to further modulate the progression of diseases. Actually, an increasing number of clinical trials have demonstrated the promising interventions and showed the feasibility of currently available treatments for future clinical translation. Targeting lymphangiogenic promoters or inhibitors not only directly regulates abnormal lymphangiogenesis, but improves the efficacy of diverse treatments. In conclusion, we present a comprehensive overview of lymphatic vessel development and physiological functions, and describe the critical involvement of abnormal lymphangiogenesis in multiple diseases. Moreover, we summarize the targeting therapeutic values of abnormal lymphangiogenesis, providing novel perspectives for treatment strategy of multiple human diseases.

Macrophages Promote Ovarian Cancer-Mesothelial Cell Adhesion by Upregulation of ITGA2 and VEGFC in Mesothelial Cells

Ovarian cancer is a metastatic disease that frequently exhibits extensive peritoneal dissemination. Recent studies have revealed that noncancerous cells inside the tumor microenvironment, such as macrophages and mesothelial cells, may play a role in ovarian cancer metastasis. In this study, we found that human ovarian cancer cells (A2780 and SKOV3) adhered more to human mesothelial Met5A cells stimulated by macrophages (M-Met5A) in comparison to unstimulated control Met5A cells. The mRNA sequencing revealed that 94 adhesion-related genes, including FMN1, ITGA2, COL13A1, VEGFC, and NRG1, were markedly upregulated in M-Met5A cells. Knockdown of ITGA2 and VEGFC in M-Met5A cells significantly inhibited the adhesion of ovarian cancer cells. Inhibition of the JNK and Akt signaling pathways suppressed ITGA2 and VEGFC expression in M-Met5A cells as well as ovarian cancer-mesothelial cell adhesion. Furthermore, increased production of CC chemokine ligand 2 (CCL2) and CCL5 by macrophages elevated ovarian cancer-mesothelial cell adhesion. These findings imply that macrophages may play a significant role in ovarian cancer-mesothelial cell adhesion by inducing the mesothelial expression of adhesion-related genes via the JNK and Akt pathways.

Inflammation in Urological Malignancies: The Silent Killer

Several studies have investigated the role of inflammation in promoting tumorigenesis and cancer progression. Neoplastic as well as surrounding stromal and inflammatory cells engage in well-orchestrated reciprocal interactions to establish an inflammatory tumor microenvironment. The tumor-associated inflammatory tissue is highly plastic, capable of continuously modifying its phenotypic and functional characteristics. Accumulating evidence suggests that chronic inflammation plays a critical role in the development of urological cancers. Here, we review the origins of inflammation in urothelial, prostatic, renal, testicular, and penile cancers, focusing on the mechanisms that drive tumor initiation, growth, progression, and metastasis. We also discuss how tumor-associated inflammatory tissue may be a diagnostic marker of clinically significant tumor progression risk and the target for future anti-cancer therapies.

Contemporary use trends and effect on survival of pelvic lymph node dissection for non-muscle-invasive bladder cancer

Background

Patients diagnosed with non-muscle-invasive bladder cancer (NMIBC) who are at a very high risk of disease progression and failure of Bacillus Calmette-Guerin treatment are recommended to undergo immediate radical cystectomy (RC). The role and optimal degree of pelvic lymph node dissection (PLND) during RC for NMIBC patients, however, have not been well investigated.

Patients and methods

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify patients. Overall survival (OS) was assessed with the Kaplan–Meier technique. Multivariable Cox regression analysis was conducted to determine independent factors of OS.

Results

A total of 1,701 patients were identified in the SEER database from 2004 to 2015. Any level of PLND (>0 lymph nodes examined) was performed in 1,092 patients (64.2%). The median number of lymph nodes examined was 8 (interquartile range, 0–20) in T1, 0 (interquartile range, 0–11) in Ta, and 0 (interquartile range, 0–14) in Tia patients. Compared with non-PLND, any level of PLND improved OS in T1 but not in Ta or Tis patients. Compared to limited (1–9 lymph nodes examined) and non-PLND, extensive PLND (lymph nodes examined ≥10) resulted in better OS only in T1 patients (all p < 0.001, adjusted significance level = 0.017). PLND was identified as a independent protective factor for OS.

Conclusion

Based on the SEER database, we found that PLND during RC led to better OS and extensive PLND was associated with better OS in T1 but not in Ta or Tis patients. The implementation of PLND was insufficient both in population proportions and scope.

In Vitro, In Vivo, and In Silico Models of Lymphangiogenesis in Solid Malignancies

Lymphangiogenesis (LA) is the formation of new lymphatic vessels by lymphatic endothelial cells (LECs) sprouting from pre-existing lymphatic vessels. It is increasingly recognized as being involved in many diseases, such as in cancer and secondary lymphedema, which most often results from cancer treatments. For some cancers, excessive LA is associated with cancer progression and metastatic dissemination to the lymph nodes (LNs) through lymphatic vessels. The study of LA through in vitro, in vivo, and, more recently, in silico models is of paramount importance in providing novel insights and identifying the key molecular actors in the biological dysregulation of this process under pathological conditions. In this review, the different biological (in vitro and in vivo) models of LA, especially in a cancer context, are explained and discussed, highlighting their principal modeled features as well as their advantages and drawbacks. Imaging techniques of the lymphatics, complementary or even essential to in vivo models, are also clarified and allow the establishment of the link with computational approaches. In silico models are introduced, theoretically described, and illustrated with examples specific to the lymphatic system and the LA. Together, these models constitute a toolbox allowing the LA research to be brought to the next level.

SULF2 is a novel diagnostic and prognostic marker for high-grade bladder cancer with lymphatic metastasis

Background

Sulfatase 2 (SULF2) is a member of the sulfatase family, and its expression and clinical significance in bladder cancer (BCa) are not currently known. In this study, we attempted to evaluate SULF2 expression in BCa patients who underwent radical cystectomy (RC) and the relationship between SULF2 expression and clinical-pathological characteristics.

Methods

Data on SULF2 expression in BCa tissues was obtained from the Oncomine database and the Gene Expression Omnibus (GEO). The expression of SULF2 and vascular endothelial growth factor-D (VEGF-D) in BCa was evaluated by immunohistochemistry (IHC) in tissues from 203 patients who had undergone RC. We also explored the value of the measurement of SULF2 and VEGF-D expression for diagnosis and prognosis in BCa patients with lymphatic metastasis.

Results

We found an increase in SULF2 messenger RNA (mRNA) levels and gene amplification in BCa tissues from the Oncomine database. High expression of SULF2 was detected in 91/203 (44.8%) of BCa patients. Among these patients, 27 of 42 (64.3%) with lymphatic metastasis showed high SULF2 expression. Univariate analysis showed that tumor size, pathological stage, lymphatic metastasis, vascular infiltration, perineural infiltration, hydronephrosis, and VEGF-D and SULF2 expression were related to prognosis in BCa patients, and multivariable Cox regression analysis showed that SULF2 expression was an independent prognostic indicator. Receiver operating characteristic (ROC) analysis revealed that SULF2 expression resulted in an increased area under the curve (AUC) of 0.707, with a sensitivity of 71.4% and a specificity of 61.5%.

Conclusions

The upregulation of SULF2 is associated with poor prognosis in high-grade BCa patients. It might be a novel diagnostic marker for BCa patients with lymphatic metastasis.

Tumor-Associated Macrophages in Bladder Cancer: Biological Role, Impact on Therapeutic Response and Perspectives for Immunotherapy

Tumor-associated macrophages (TAMs) are one of the most abundant infiltrating immune cells of solid tumors. Despite their possible dual role, i.e., pro- or anti-tumoral, there is considerable evidence showing that the accumulation of TAMs promotes tumor progression rather than slowing it. Several strategies are being developed and clinically tested to target these cells. Bladder cancer (BCa) is one of the most common cancers, and despite heavy treatments, including immune checkpoint inhibitors (ICIs), the overall patient survival for advanced BCa is still poor. TAMs are present in bladder tumors and play a significant role in BCa development. However, few investigations have analyzed the effect of targeting TAMs in BCa. In this review, we focus on the importance of TAMs in a cancerous bladder, their association with patient outcome and treatment efficiency as well as on how current BCa treatments impact these cells. We also report different strategies used in other cancer types to develop new immunotherapeutic strategies with the aim of improving BCa management through TAMs targeting.

Immune escape mechanisms and immunotherapy of urothelial bladder cancer

BACKGROUND AND AIM

Urothelial bladder cancer (UBC) is a common malignant tumor of the urogenital system with a high rate of recurrence. Due to the sophisticated and largely unexplored mechanisms of tumorigenesis of UBC, the classical therapeutic approaches including transurethral resection and radical cystectomy combined with chemotherapy have remained unchanged for decades. However, with increasingly in-depth understanding of the microenvironment and the composition of tumor-infiltrating lymphocytes of UBC, novel immunotherapeutic strategies have been developed. Bacillus Calmette-Guerin (BCG) therapy, immune checkpoint blockades, adoptive T cell immunotherapy, dendritic cell (DC) vaccines, etc., have all been intensively investigated as immunotherapies for UBC. This review will discuss the recent progress in immune escape mechanisms and immunotherapy of UBC.

METHODS

Based on a comprehensive search of the PubMed and ClinicalTrials.gov database, this review included the literature reporting the immune escape mechanisms of UBC and clinical trials assessing the effect of immunotherapeutic strategies on tumor or immune cells in UBC patients published in English between 1999 and 2020.

RESULTS

Immune surveillance, immune balance, and immune escape are the three major processes that occur during UBC tumorigenesis. First, the role of immunosuppressive cells, immunosuppressive molecules, immunosuppressive signaling molecules, and DCs in tumor microenvironment is introduced elaborately in the immune escape mechanisms of UBC section. In addition, recent progress of immunotherapies including BCG, checkpoint inhibitors, cytokines, adoptive T cell immunotherapy, DCs, and macrophages on UBC patients are summarized in detail. Finally, the need to explore the mechanisms, molecular characteristics and immune landscape during UBC tumorigenesis and development of novel and robust immunotherapies for UBC are also proposed and discussed.

CONCLUSION

At present, BCG and immune checkpoint blockades have been approved by the US Food and Drug Administration for the treatment of UBC patients and have achieved encouraging therapeutic results, expanding the traditional chemotherapy and surgery-based treatment for UBC.

RELEVANCE FOR PATIENTS

Immunotherapy has achieved desirable results in the treatment of UBC, which not only improve the overall survival but also reduce the recurrence rate and the occurrence of treatment-related adverse events of UBC patients. In addition, the indicators to predict the effectiveness and novel therapy strategies, such as combination regimen of checkpoint inhibitor with checkpoint inhibitor or chemotherapy, should be further studied.

[A Review of Celluar Senescence and Tumor Treatment]

Cellular senescence is a permanent state of cell cycle arrest, combined with the acquisition of a variety of secretory phenotypes. In addition to apoptosis, the induction of cellular senescence is an important mechanism that chemo- and radiotherapies and some targeted therapies rely on to produce an anti-tumor effect. However, being a self-protective mechanism of cells, cellular senescence can produce both positive and negative effects in tumor treatment. It remains a challenge to effectively utilize the anti-tumor effect of cellular senescence while averting the pro-tumor effect. How to improve the sensitivity of tumor treatment and to prevent tumor recurrence and metastasis has become the bottleneck in cellular senescence research. We summarize in this review the "double-edged-sword" effect of cellular senescence in tumor treatment. We summarize and discuss the cell autonomous and non-autonomous mechanisms that senescent cells use to affect tumor treatment, hoping to provide information that will help improve the outcome of tumor treatment and promote further research in basic and clinical application of cellular senescence in tumor treatment.

Screening for potential targets to reduce stenosis in bioprosthetic heart valves

Progressive stenosis is one of the main factors that limit the lifetime of bioprosthetic valved conduits. To improve long-term performance we aimed to identify targets that inhibit pannus formation on conduit walls. From 11 explanted, obstructed, RNAlater presevered pulmonary valved conduits, we dissected the thickened conduit wall and the thin leaflet to determine gene expression-profiles using ultra deep sequencing. Differential gene expression between pannus and leaflet provided the dataset that was screened for potential targets. Promising target candidates were immunohistologically stained to see protein abundance and the expressing cell type(s). While immunostainings for DDR2 and FGFR2 remained inconclusive, EGFR, ErbB4 and FLT4 were specifically expressed in a subset of tissue macrophages, a cell type known to regulate the initiation, maintenance, and resolution of tissue repair. Taken toghether, our data suggest EGFR, ErbB4 and FLT4 as potential target candidates to limit pannus formation in bioprosthestic replacement valves.

Lymphatic Vasculature: An Emerging Therapeutic Target and Drug Delivery Route

The lymphatic system has received increasing scientific and clinical attention because a wide variety of diseases are linked to lymphatic pathologies and because the lymphatic system serves as an ideal conduit for drug delivery. Lymphatic vessels exert heterogeneous roles in different organs and vascular beds, and consequently, their dysfunction leads to distinct organ-specific outcomes. Although studies in animal model systems have led to the identification of crucial lymphatic genes with potential therapeutic benefit, effective lymphatic-targeted therapeutics are currently lacking for human lymphatic pathological conditions. Here, we focus on the therapeutic roles of lymphatic vessels in diseases and summarize the promising therapeutic targets for modulating lymphangiogenesis or lymphatic function in preclinical or clinical settings. We also discuss considerations for drug delivery or targeting of lymphatic vessels for treatment of lymphatic-related diseases. The lymphatic vasculature is rapidly emerging as a critical system for targeted modulation of its function and as a vehicle for innovative drug delivery.

Cellular Origins of the Lymphatic Endothelium: Implications for Cancer Lymphangiogenesis

The lymphatic system plays important roles in physiological and pathological conditions. During cancer progression in particular, lymphangiogenesis can exert both positive and negative effects. While the formation of tumor associated lymphatic vessels correlates with metastatic dissemination, increased severity and poor patient prognosis, the presence of functional lymphatics is regarded as beneficial for anti-tumor immunity and cancer immunotherapy delivery. Therefore, a profound understanding of the cellular origins of tumor lymphatics and the molecular mechanisms controlling their formation is required in order to improve current strategies to control malignant spread. Data accumulated over the last decades have led to a controversy regarding the cellular sources of tumor-associated lymphatic vessels and the putative contribution of non-endothelial cells to this process. Although it is widely accepted that lymphatic endothelial cells (LECs) arise mainly from pre-existing lymphatic vessels, additional contribution from bone marrow-derived cells, myeloid precursors and terminally differentiated macrophages, has also been claimed. Here, we review recent findings describing new origins of LECs during embryonic development and discuss their relevance to cancer lymphangiogenesis.

Soluble Vegfr3 gene therapy suppresses multi-organ metastasis in a mouse mammary cancer model

Accumulating evidence on the association of VEGF-C with lymphangiogenesis and lymph node metastasis implicates lymphatic vessels as a potential target in anti-cancer therapy. To evaluate whether blocking VEGF-C and VEGFR-3 signaling can inhibit multi-organ metastases, a mouse metastatic mammary cancer model was subjected to gene therapy using a soluble VEGFR-3 expression vector (psVEGFR-3). We showed that psVEGFR-3 significantly diminished cell growth in vitro with or without added VEGF-C, and significantly reduced primary tumor growth and tumor metastases to wide-spectrum organs in vivo. Although apoptotic cell death and angiogenesis levels did not differ between the control and psVEGFR-3 groups, cell proliferation and lymphangiogenesis in the mammary tumors were significantly decreased in the psVEGFR-3 group. Furthermore, lymphatic vessel invasion was significantly inhibited in this group. Real-time RT-PCR analysis revealed significantly high expression of the Vegfr3 gene due to gene therapy, and the transcriptional levels of Pcna and Lyve1 tended to decrease in the psVEGFR-3 group. Immunofluorescence staining indicated that phospho-tyrosine expression was considerably lower in tumor cells of psVEGFR-3-treated mammary carcinomas than those of control tumors. Double immunofluorescence staining indicated that phospho-tyrosine⁺ /LYVE-1⁺ (a lymphatic vessel marker) tended to decrease in psVEGFR-3-treated mammary carcinomas compared with control mice, indicating a decline in the activity of the VEGF-C/VEGFR-3 axis. These findings showed that a blockade of VEGF-C/VEGFR-3 signaling caused by sVEGFR-3 sequestered VEGF-C and prevented the side-effects of anti-angiogenesis and suppressed overall metastases, suggesting their high clinical significance.

circNFIB1 inhibits lymphangiogenesis and lymphatic metastasis via the miR-486-5p/PIK3R1/VEGF-C axis in pancreatic cancer

BACKGROUND

Patients with lymph node (LN)-positive pancreatic ductal adenocarcinoma (PDAC) have extremely poor survival rates. Circular RNAs (circRNAs), a newly discovered type of endogenous noncoding RNAs, have been proposed to mediate the progression of diverse types of tumors. However, the role and underlying regulatory mechanisms of circRNAs in the LN metastasis of PDAC remain unknown.

METHODS

Next-generation sequencing was used to identify differentially expressed circRNAs between PDAC and normal adjacent tissues. In vitro and in vivo experiments were conducted to evaluate the functional role of circNFIB1. RNA pulldown and luciferase assays were performed to examine the binding of circNFIB1 and miR-486-5p.

RESULTS

In the present study, we identified that a novel circRNA (circNFIB1, hsa_circ_0086375) was downregulated in PDAC and negatively associated with LN metastasis in PDAC patients. Functionally, circNFIB1 knockdown promoted lymphangiogenesis and LN metastasis of PDAC both in vitro and in vivo. Mechanistically, circNFIB1 functioned as a sponge of miR-486-5p, and partially reversed the effect of miR-486-5p. Moreover, circNFIB1 attenuated the oncogenic effect of miR-486-5p and consequently upregulated PIK3R1 expression, which further downregulated VEGF-C expression through inhibition of the PI3K/Akt pathway, and ultimately suppressed lymphangiogenesis and LN metastasis in PDAC.

CONCLUSIONS

Our findings provide novel insight into the underlying mechanism of circRNA-mediated LN metastasis of PDAC and suggest that circNFIB1 may serve as a potential therapeutic target for LN metastasis in PDAC.

Lymphatic Endothelial Cell Progenitors in the Tumor Microenvironment

Tumor lymphatics play a key role in cancer progression as they are solely responsible for transporting malignant cells to regional lymph nodes (LNs), a process that precedes and promotes systemic lethal spread. It is broadly accepted that tumor lymphatic sprouting is induced mainly by soluble factors derived from tumor-associated macrophages (TAMs) and malignant cells. However, emerging evidence strongly suggests that a subset of TAMs, myeloid-lymphatic endothelial cell progenitors (M-LECP), also contribute to the expansion of lymphatics through both secretion of paracrine factors and a self-autonomous mode. M-LECP are derived from bone marrow (BM) precursors of the monocyte-macrophage lineage and characterized by unique co-expression of markers identifying lymphatic endothelial cells (LEC), stem cells, M2-type macrophages, and myeloid-derived immunosuppressive cells. This review describes current evidence for the origin of M-LECP in the bone marrow, their recruitment tumors and intratumoral trafficking, similarities to other TAM subsets, and mechanisms promoting tumor lymphatics. We also describe M-LECP integration into preexisting lymphatic vessels and discuss potential mechanisms and significance of this event. We conclude that improved mechanistic understanding of M-LECP functions within the tumor environment may lead to new therapeutic approaches to suppress tumor lymphangiogenesis and metastasis to lymph nodes.

Communication Of Cancer Cells And Lymphatic Vessels In Cancer: Focus On Bladder Cancer

Bladder cancer is one of the most commonly diagnosed cancers worldwide and causes the highest lifetime treatment costs per patient. Bladder cancer is most likely to metastasize through lymphatic ducts, and once the lymph nodes are involved, the prognosis is poorly and finitely improved by current modalities. The underlying metastatic mechanism for bladder cancer is thus becoming a research focus to date. To identify relevant published data, an online search of the PubMed/Medline archives was performed to locate original articles and review articles regarding lymphangiogenesis and lymphatic metastasis in urinary bladder cancer (UBC), and was limited to articles in English published between 1998 and 2018. A further search of the clinical trials.gov search engine was conducted to identify both trials with results available and those with results not yet available. Herein, we summarized the unique mechanisms and biomarkers involved in the malignant progression of bladder cancer as well as their emerging roles in therapeutics, and that current data suggests that lymphangiogenesis and lymph node invasion are important prognostic factors for UBC. The growing knowledge about their roles in bladder cancers provides the basis for novel therapeutic strategies. In addition, more basic and clinical research needs to be conducted in order to identify further accurate predictive molecules and relevant mechanisms.

Biomaterials for Modulating Lymphatic Function in Immunoengineering

Immunoengineering is a rapidly growing and interdisciplinary field focused on developing tools to study and understand the immune system, then employing that knowledge to modulate immune response for the treatment of disease. Because of its roles in housing a substantial fraction of the body's lymphocytes, in facilitating immune cell trafficking, and direct immune modulatory functions, among others, the lymphatic system plays multifaceted roles in immune regulation. In this review, the potential for biomaterials to be applied to regulate the lymphatic system and its functions to achieve immunomodulation and the treatment of disease are described. Three related processes-lymphangiogenesis, lymphatic vessel contraction, and lymph node remodeling-are specifically explored. The molecular regulation of each process and their roles in pathologies are briefly outlined, with putative therapeutic targets and the lymphatic remodeling that can result from disease highlighted. Applications of biomaterials that harness these pathways for the treatment of disease via immunomodulation are discussed.

STING signaling is a potential immunotherapeutic target in colorectal cancer

Background: Stimulator of Interferon Genes (STING) is an innate immune sensor for cytosolic DNA. STING signaling activation is indispensable for type I interferon response and the anti-cancer immune response by CD8⁺ T cells. The aim of this study was to characterize intratumoral STING expression pattern and its clinical implication in colorectal cancer (CRC). Methods: We analyzed STING and CD8 expression in 225 CRC patients who underwent surgical resection. Clinicopathological variables and survival outcomes were analyzed according to STING expression levels. Mice with syngeneic MC38 tumors were also treated with a STING agonist, and tumor microenvironments were analyzed using immunofluorescent staining and flow cytometry. Results: Distinct STING expression was observed in the CRC tumor specimens. Patients with higher STING expression had early stage cancer with increased intratumoral CD8⁺ T cell infiltration and less frequent lymphovascular invasion. Compared to CRC patients with lower STING expression, those with higher STING expression had longer overall and recurrence-free survival. Multivariate Cox regression model also revealed higher STING expression to be an independent prognostic factor for better overall survival. When MC38 colon tumors were treated with intratumoral injection of STING agonist, tumor growth was remarkably suppressed with increased intratumoral CD8⁺ T cell infiltration. Moreover, T-cell activation markers, ICOS and IFN-γ, were also upregulated in CD8⁺ T cells, indicating enhanced effector T cell function after STING treatment. Conclusion: We confirmed the distinct STING expression in CRC and demonstrated its independent prognostic value in survival outcomes. STING could be a potential therapeutic target that enhances anti-cancer immune response in CRC.

STING activation reprograms tumor vasculatures and synergizes with VEGFR2 blockade

The stimulator of interferon genes (STING) signaling pathway is a critical link between innate and adaptive immunity, and induces anti-tumor immune responses. STING is expressed in vasculatures, but its role in tumor angiogenesis has not been elucidated. Here we investigated STING-induced tumor vascular remodeling and the potential of STING-based combination immunotherapy. Endothelial STING expression was correlated with enhanced T-cell infiltration and prolonged survival in human colon and breast cancer. Intratumoral STING activation with STING agonists (cGAMP or RR-CDA) normalized tumor vasculatures in implanted and spontaneous cancers, but not in STING-deficient mice. These were mediated by upregulation of type I/II interferon genes and vascular stabilizing genes (e.g., Angpt1, Pdgfrb, and Col4a). STING in non-hematopoietic cells is as important as STING in hematopoietic cells to induce a maximal therapeutic efficacy of exogenous STING agonist. Vascular normalizing effects of STING agonists were dependent on type I interferon signaling and CD8+ T cells. Notably, STING-based immunotherapy was maximally effective when combined with VEGFR2 blockade and/or immune checkpoint blockade (αPD-1 or αCTLA-4), leading to complete regression of immunotherapy-resistant tumors. Our data show that intratumoral STING activation can normalize tumor vasculature and the tumor microenvironment, providing a rationale for combining STING-based immunotherapy and anti-angiogenic therapy.

Inhibition of lymphatic proliferation by the selective VEGFR-3 inhibitor SAR131675 ameliorates diabetic nephropathy in db/db mice

Recent studies have demonstrated that chronic inflammation-induced lymphangiogenesis plays a crucial role in the progression of various renal diseases, including diabetic nephropathy. SAR131675 is a selective vascular endothelial cell growth factor receptor-3 (VEGFR-3)-tyrosine kinase inhibitor that acts as a ligand for VEGF-C and VEGF-D to inhibit lymphangiogenesis. In this study, we evaluated the effect of SAR131675 on renal lymphangiogenesis in a mouse model of type 2 diabetes. Male C57BLKS/J db/m and db/db mice were fed either a regular chow diet or a diet containing SAR131675 for 12 weeks from 8 weeks of age. In addition, we studied palmitate-induced lymphangiogenesis in human kidney-2 (HK2) cells and RAW264.7 monocytes/macrophages, which play a major role in lymphangiogenesis in the kidneys. SAR131475 ameliorated dyslipidemia, albuminuria, and lipid accumulation in the kidneys of db/db mice, with no significant changes in glucose and creatinine levels and body weight. Diabetes-induced systemic inflammation as evidenced by increased systemic monocyte chemoattractant protein-1 and tumor necrosis factor-α level was decreased by SAR131475. SAR131475 ameliorated the accumulation of triglycerides and free fatty acids and reduced inflammation in relation to decreased chemokine expression and pro-inflammatory M1 macrophage infiltration in the kidneys. Downregulation of VEGF-C and VEGFR-3 by SAR131475 inhibited lymphatic growth as demonstrated by decreased expression of LYVE-1 and podoplanin that was further accompanied by reduced tubulointerstitial fibrosis, and inflammation in relation to improvement in oxidative stress and apoptosis. Treatment with SAR131475 improved palmitate-induced increase in the expression of VEGF-C, VEGFR-3, and LYVE-1, along with improvement in cytosolic and mitochondrial oxidative stress in RAW264.7 and HK2 cells. Moreover, the enhanced expression of M1 phenotypes in RAW264.7 cells under palmitate stress was reduced by SAR131475 treatment. The results suggest that modulation of lymphatic proliferation in the kidneys is a new treatment approach for type 2 diabetic nephropathy and that SAR131675 is a promising therapy to ameliorate renal damage by reducing lipotoxicity-induced lymphangiogenesis.

Polypyrimidine tract binding protein 1 promotes lymphatic metastasis and proliferation of bladder cancer via alternative splicing of MEIS2 and PKM

Lymph node (LN) metastasis is the leading cause of bladder cancer-related mortality. Splicing factors facilitate cancer progression by modulating oncogenic variants, but it is unclear whether and how splicing factors regulate bladder cancer LN metastasis. In this study, Polypyrimidine tract binding protein 1 (PTBP1) expression was found to relate to bladder cancer LN metastasis, and was positively correlated with LN metastasis status, tumor stage, histological grade, and poor patient prognosis. Functional assays demonstrated that PTBP1 promoted bladder cancer cell migration, invasion, and proliferation in vitro, as well as LN metastasis and tumor growth in vivo. Mechanistic investigations revealed that PTBP1 upregulated MEIS2-L variant to promote metastasis and increased expression of PKM2 variant to enhance proliferation by modulating alternative mRNA splicing. Moreover, overexpression of MEIS2-L or PKM2 could rescue the oncogenic abilities of bladder cancer cells and the expression of MMP9 or CCND1 respectively after PTBP1 knockdown. In conclusion, our data demonstrate that PTBP1 induces bladder cancer LN metastasis and proliferation through an alternative splicing mechanism. PTBP1 may serve as a novel prognostic marker and therapeutic target for LN-metastatic bladder cancer.

Predictive value of lymphangiogenesis and proliferation markers on mRNA level in urothelial carcinoma of the bladder after radical cystectomy

OBJECTIVE

To evaluate the mRNA expression of lymphangiogenesis and proliferation markers and to examine its association with histopathological characteristics and clinical outcome in patients with urothelial carcinoma of the bladder (UCB) after radical cystectomy (RC).

PATIENTS AND METHODS

Gene expression analysis of the vascular endothelial growth -C and -D (VEGF-C/-D), its receptor VEGF receptor-3 (VEGFR-3), MKI67, and RACGAP1 was performed in 108 patients after radical cystectomy and their correlation with clinical-pathological parameters was investigated. Uni- and multivariate regression analyses were used to identify predictors for cancer-specific survival (CSS), recurrence-free survival (RFS) and overall survival (OS) after RC.

RESULTS

The expression of RACGAP1 and VEGFR-3 showed an association with a higher pT stage (P = 0.049; P = 0.009). MKI67 showed an association with a high-grade urothelial carcinoma of the bladder (P = 0.021). VEGFR-3 expression was significantly associated with the presence of lymphovascular invasion (LVI) (P = 0.016) and lymph node metastases (pN+) (P = 0.028). With the univariate analysis, overexpression of VEGFR-3 (P = 0.029) and the clinical-pathological parameters pT stage (P < 0.0001), pN+ (P = 0.0004), LVI (P < 0.0001) and female gender (P = 0.021) were significantly associated with a reduced CSS. Multivariate analysis identified a higher pT stage (P = 0.017) and LVI (P = 0.008) as independent predictors for reduced CSS. Independent predictors for reduced OS were a higher pT stage (P = 0.0007) and LVI (P = 0.0021), while overexpression of VEGF-D was associated with better OS (P < 0.0001).

CONCLUSIONS

The mRNA expression of the investigated markers showed associations with common histopathological parameters. Increased expression of VEGF-D is independently associated with better overall survival.

Macrophage Polarization in Chronic Inflammatory Diseases: Killers or Builders?

Macrophages are key cellular components of the innate immunity, acting as the main player in the first-line defence against the pathogens and modulating homeostatic and inflammatory responses. Plasticity is a major feature of macrophages resulting in extreme heterogeneity both in normal and in pathological conditions. Macrophages are not homogenous, and they are generally categorized into two broad but distinct subsets as either classically activated (M1) or alternatively activated (M2). However, macrophages represent a continuum of highly plastic effector cells, resembling a spectrum of diverse phenotype states. Induction of specific macrophage functions is closely related to the surrounding environment that acts as a relevant orchestrator of macrophage functions. This phenomenon, termed polarization, results from cell/cell, cell/molecule interaction, governing macrophage functionality within the hosting tissues. Here, we summarized relevant cellular and molecular mechanisms driving macrophage polarization in "distant" pathological conditions, such as cancer, type 2 diabetes, atherosclerosis, and periodontitis that share macrophage-driven inflammation as a key feature, playing their dual role as killers (M1-like) and/or builders (M2-like). We also dissect the physio/pathological consequences related to macrophage polarization within selected chronic inflammatory diseases, placing polarized macrophages as a relevant hallmark, putative biomarkers, and possible target for prevention/therapy.

Binding of human recombinant mutant soluble ectodomain of FGFR2IIIc to c subtype of FGFRs: implications for anticancer activity

FGFRs are considered essential targets for cancer therapy. We previously reported that msFGFR2c, a Ser252Trp mutant soluble ectodomain of FGFR2IIIc, inhibited tumor growth by blocking FGF signaling pathway. However, the underlying molecular mechanism is still obscure. In this study, we reported that msFGFR2c but not wild-type soluble ectodomain of FGFR2IIIc (wsFGFR2c) could selectively bind to c subtype of FGFRs in the presence of FGF-2. Thermodynamic analysis demonstrated that msFGFR2c bound to wsFGFR2c in the presence of FGF-2 with a K value of 6.61 × 10⁵ M⁻¹. Molecular dynamics simulations revealed that the mutated residue Trp252 of msFGFR2c preferred a π-π interaction with His254 of wsFGFR2c. Concomitantly, Arg255 of msFGFR2c and Glu250 of wsFGFR2c adjusted their conformations and formed three H-bonds. These two interactions therefore stabilized the final structure of wsFGFR2c and msFGFR2c heterocomplex. In FGFR2IIIc-positive/high FGF-2-secreted BT-549 cells, msFGFR2c significantly inhibited the proliferation and induced apoptosis by the blockage of FGF-2-activated FGFRs phosphorylation, also the growth and angiogenesis of its xenograft tumors implanted in chick embryo chorioallantoic membrane model. While weaker the above inhibitory effects of msFGFR2c were observed on FGFR2IIIc-negative/low FGF-2-secreted MCF-7 and MDA-MB-231 cell lines in vitro and in vivo. Moreover, msFGFR2c significantly inhibited the proliferation of FGFR1IIIc-positive NCI-H1299 lung cancer cells by the suppression of FGF-2-induced FGFR1 activation and suppressed the growth of NCI-H1299 transplanted tumors in nude mice. In sum, msFGFR2c is a potential anti-tumor agent targeting FGFR2c/FGFR1c-positive tumor cells. These findings also provide a molecular basis for msFGFR2c to disrupt the activation of FGF signaling.

Macrophage Polarization in Chronic Inflammatory Diseases: Killers or Builders?

Macrophages are key cellular components of the innate immunity, acting as the main player in the first-line defence against the pathogens and modulating homeostatic and inflammatory responses. Plasticity is a major feature of macrophages resulting in extreme heterogeneity both in normal and in pathological conditions. Macrophages are not homogenous, and they are generally categorized into two broad but distinct subsets as either classically activated (M1) or alternatively activated (M2). However, macrophages represent a continuum of highly plastic effector cells, resembling a spectrum of diverse phenotype states. Induction of specific macrophage functions is closely related to the surrounding environment that acts as a relevant orchestrator of macrophage functions. This phenomenon, termed polarization, results from cell/cell, cell/molecule interaction, governing macrophage functionality within the hosting tissues. Here, we summarized relevant cellular and molecular mechanisms driving macrophage polarization in “distant” pathological conditions, such as cancer, type 2 diabetes, atherosclerosis, and periodontitis that share macrophage-driven inflammation as a key feature, playing their dual role as killers (M1-like) and/or builders (M2-like). We also dissect the physio/pathological consequences related to macrophage polarization within selected chronic inflammatory diseases, placing polarized macrophages as a relevant hallmark, putative biomarkers, and possible target for prevention/therapy.

The synergistic effect of esophageal squamous cell carcinoma KYSE150 cells and M2 macrophages on lymphatic endothelial cells

Objective: This study aimed to investigate whether tumor-associated macrophages (TAMs) and esophageal squamous cell carcinoma (ESCC) cells could synergistically influence the generation of lymphatic vessels via the VEGF-C/VEGFR-3 signaling pathway and to address its mechanism. Methods: M2 macrophages were sorted with immunomagnetic beads and induced in vitro. VEGF-C siRNA plasmids were constructed and transfected into M2 macrophages and the ESCC cell line KYSE150. Different conditioned culture media before and after transfection were collected and classified into different groups for culturing ESCC-associated lymphatic endothelial cells (ESCC-LECs). Using the CCK-8 assay, Transwell cell migration assay and Matrigel three-dimensional culture, the proliferation, migration and ring forming abilities of ESCC-LECs before and after transfection were compared, respectively. With ELISA, western blot and q(RT)-PCR, VEGF-C concentrations in conditioned culture media and the protein and mRNA expression levels of VEGFR-3 in LECs before and after transfection were compared, respectively. Results: Before transfection, ESCC-LECs in the group with mixed culture medium had stronger proliferation, migration and ring forming abilities than the other groups. The VEGF-C concentration and VEGFR-3 protein and mRNA expression levels were higher in the mixed culture medium group than in the other groups. After transfection, all indices were the lowest in the mixed culture medium group. Conclusions: M2 macrophages can enhance the proliferation, migration and ring forming abilities of ESCC-LECs. ESCC cells and M2 macrophages have synergistic effects on the proliferation, migration and ring forming abilities of ESCC-LECs. VEGF-C siRNA can inhibit the proliferation, migration and ring forming abilities of ESCC-LECs by silencing the expression of VEGF-C and its receptor VEGFR-3 in KYSE150 cells and M2 macrophages.

VEGFR3 inhibition chemosensitizes lung adenocarcinoma A549 cells in the tumor-associated macrophage microenvironment through upregulation of p53 and PTEN

In lung adenocarcinoma, loss of p53 and PTEN in tumors are associated with decreased response to chemotherapy and decreased survival. A means to pharmacologically upregulate p53 and PTEN protein expression could improve the prognosis of patients with p53- and PTEN-deficient tumors. In the present study we revealed that vascular endothelial growth factor receptor 3 (VEGFR3) inhibition in lung adenocarcinoma cells was associated with improved expression levels of both p53 and PTEN in the tumor-associated macrophage (TAM) microenvironment. Inhibition of VEGFR3 in lung adenocarcinoma cells was associated with growth arrest and decreased migration and invasion. The upregulation of p53 and PTEN protein expression after VEGFR3 inhibition decreased chemotherapy resistance and improved chemosensitivity in co-cultured A549 cells in which p53 and PTEN expression were decreased. Finally, we demonstrated that TAMs promoted the expression of VEGF-C and its receptor VEGFR3. Western blot analysis revealed the co-cultured A549 cells with TAMs are a primary source of VEGF-C and VEGFR3 in the tumor microenvironment. Our studies revealed that VEGFR3 inhibition may be a pharmacological means to upregulate p53 and PTEN protein expression and improve the outcome of patients with p53- and PTEN-deficient tumors.

MicroRNA-186 regulates the invasion and metastasis of bladder cancer via vascular endothelial growth factor C

The present study aimed to investigate the expression of microRNA (miRNA or miR)-186 in tumor tissue, blood and urine from patients with bladder cancer. The mechanism by which miR-186 regulates the invasion and metastasis of bladder cancer was also assessed. A total of 76 patients who underwent surgical resection of bladder cancer tissues between August 2012 and January 2016 were included in the present study. Blood and urine samples were also collected from the 76 patients and another 66 healthy subjects. Expression of vascular endothelial growth factor C (VEGF-C) mRNA and miR-186 was measured using reverse transcription-quantitative polymerase chain reaction. Western blot analysis was performed to assess VEGF-C protein expression in tumor tissues. The content of VEGF-C protein in blood and urine samples was measured using an enzyme-linked immunosorbent assay. To identify the direct interaction between miR-186 and VEGF-C mRNA, a dual luciferase reporter assay was performed. The present findings demonstrated that VEGF-C mRNA expression in tumor tissues, blood and urine of bladder cancer patients was upregulated. VEGF-C protein expression in bladder cancer tissues was also enhanced. VEGF-C protein content in blood and urine from bladder cancer patients was elevated, consistent with the results for VEGF-C mRNA. Expression of miR-186 was reduced in tumor tissues, blood and urine. Dual luciferase reporter assay demonstrated that miR-186 regulated the expression of VEGF-C by binding with its 3'-untranslated region. Therefore, the results of the present study indicate that the expression of VEGF-C mRNA and protein is upregulated in tumor tissues, blood and urine from patients with bladder cancer, while that of miR-186 is downregulated in these samples. miR-186 potentially regulates the invasion and metastasis of bladder cancer via VEGF-C, and may become a gene marker for bladder cancer in the future.

S1P Provokes Tumor Lymphangiogenesis via Macrophage-Derived Mediators Such as IL-1β or Lipocalin-2

A pleiotropic signaling lipid, sphingosine-1-phosphate (S1P), has been implicated in various pathophysiological processes supporting tumor growth and metastasis. However, there are only a few descriptive studies suggesting a role of S1P in tumor lymphangiogenesis, which is critical for tumor growth and dissemination. Corroborating own data, the literature suggests that apoptotic tumor cell-derived S1P alters the phenotype of tumor-associated macrophages (TAMs) to gain protumor functions. However, mechanistically, the role of TAM-induced lymphangiogenesis has only been poorly described, mostly linked to the production of lymphangiogenic factors such as vascular endothelial growth factor C (VEGF-C) and VEGF-D, or transdifferentiation into lymphatic endothelial cells. Recent findings highlight a rather underappreciated role of S1P in tumor lymphangiogenesis, referring to the production of interleukin-1β (IL-1β) and lipocalin-2 (LCN2) by a tumor-promoting macrophage phenotype. In this review, we aim to provide to the readers with the current understanding of the molecular mechanism how apoptotic cell-derived S1P triggers TAMs to promote lymphangiogenesis.

Novel role of immature myeloid cells in formation of new lymphatic vessels associated with inflammation and tumors

Inflammation triggers an immune cell-driven program committed to restoring homeostasis to injured tissue. Central to this process is vasculature restoration, which includes both blood and lymphatic networks. Generation of new vessels or remodeling of existing vessels are also important steps in metastasis-the major cause of death for cancer patients. Although roles of the lymphatic system in regulation of inflammation and cancer metastasis are firmly established, the mechanisms underlying the formation of new lymphatic vessels remain a subject of debate. Until recently, generation of new lymphatics in adults was thought to occur exclusively through sprouting of existing vessels without help from recruited progenitors. However, emerging findings from clinical and experimental studies show that lymphoendothelial progenitors, particularly those derived from immature myeloid cells, play an important role in this process. This review summarizes current evidence for the existence and significant roles of myeloid-derived lymphatic endothelial cell progenitors (M-LECPs) in generation of new lymphatics. We describe specific markers of M-LECPs and discuss their biologic behavior in culture and in vivo, as well as currently known molecular mechanisms of myeloid-lymphatic transition (MLT). We also discuss the implications of M-LECPs for promoting adaptive immunity, as well as cancer metastasis. We conclude that improved mechanistic understanding of M-LECP differentiation and its role in adult lymphangiogenesis may lead to new therapeutic approaches for correcting lymphatic insufficiency or excessive formation of lymphatic vessels in human disorders.

Myeloid cells pave the way for lymphatic system development and maintenance

The maintenance of tissue homeostasis is indispensable for health. In particular, removal of toxic compounds from cells and organs is a vital process for the organism. The lymphatic vasculature works in order to ensure the efficient removal of tissue waste. Forbidden over the last decade when more attention was paid to the blood vasculature, studies on the lymphatic vasculature have gained momentum during the last couple of years. The lymphatic vasculature naturally runs parallel to the blood vasculature and their synergistic work is critical for maintaining tissue homeostasis. Diminished lymphatic function results in accumulation of body fluids in tissues and gives rise to edema. Recently, it became obvious that immune cells including myeloid cells and lymphocytes are able to interact with and control the development and function of the lymphatic vasculature. In this review, we will focus on the interaction between myeloid cells, including macrophages, monocytes, and dendritic cells, with lymphatic vessels.

Blockade of FLT4 suppresses metastasis of melanoma cells by impaired lymphatic vessels

The metastatic spread of tumor cells via lymphatic vessels affects the relapse of tumor patients. New lymphatic vessel formation, including lymphangiogenesis, is promoted in the tumor environment. The lymphangiogenic factor VEGF-C can mediate lymphatic vessel formation and induce tumor metastasis by binding with FLT4. In melanoma, metastasis via lymphatics such as lymph nodes is one of the main predictors of poor outcome. Thus, we investigated whether blockade of FLT4 can reduce metastasis via the suppression of lymphatic capillaries. Proliferative lymphatic capillaries in melanoma were estimated by immunohistochemistry using FLT4 antibody after the injection of the FLT4 antagonist MAZ51. The numbers of tumor modules in metastasised lungs were calculated by gross examination and lymphatic related factors were examined by qRT-PCR. MAZ51 injection resulted in the suppression of tumor size and module number and the inhibition of proliferative lymphatic vessels in the intratumoral region in the lung and proliferating melanoma cells in the lung compared to those of untreated groups. Additionally, high FLT4 and TNF-alpha were detected in melanoma-induced tissue, while lymphatic markers such as VEGF-C, FLT4 and Prox-1 were significantly decreased in MAZ51 treated groups, implying that anti-lymphangiogenesis by MAZ51 may provide a potential strategy to prevent tumor metastasis in melanoma and high number of lymphatic capillaries could be used diagnosis for severe metastasis.

DeepCAGE transcriptomics identify HOXD10 as a transcription factor regulating lymphatic endothelial responses to VEGF-C

Lymphangiogenesis plays a crucial role during development, in cancer metastasis and in inflammation. Activation of VEGFR-3 (also known as FLT4) by VEGF-C is one of the main drivers of lymphangiogenesis, but the transcriptional events downstream of VEGFR-3 activation are largely unknown. Recently, we identified a wave of immediate early transcription factors that are upregulated in human lymphatic endothelial cells (LECs) within the first 30 to 80 min after VEGFR-3 activation. Expression of these transcription factors must be regulated by additional pre-existing transcription factors that are rapidly activated by VEGFR-3 signaling. Using transcription factor activity analysis, we identified the homeobox transcription factor HOXD10 to be specifically activated at early time points after VEGFR-3 stimulation, and to regulate expression of immediate early transcription factors, including NR4A1. Gain- and loss-of-function studies revealed that HOXD10 is involved in LECs migration and formation of cord-like structures. Furthermore, HOXD10 regulates expression of VE-cadherin, claudin-5 and NOS3 (also known as e-NOS), and promotes lymphatic endothelial permeability. Taken together, these results reveal an important and unanticipated role of HOXD10 in the regulation of VEGFR-3 signaling in lymphatic endothelial cells, and in the control of lymphangiogenesis and permeability.

The Reactive Oxygen Species in Macrophage Polarization: Reflecting Its Dual Role in Progression and Treatment of Human Diseases

High heterogeneity of macrophage is associated with its functions in polarization to different functional phenotypes depending on environmental cues. Macrophages remain in balanced state in healthy subject and thus macrophage polarization may be crucial in determining the tissue fate. The two distinct populations, classically M1 and alternatively M2 activated, representing the opposing ends of the full activation spectrum, have been extensively studied for their associations with several disease progressions. Accumulating evidences have postulated that the redox signalling has implication in macrophage polarization and the key roles of M1 and M2 macrophages in tissue environment have provided the clue for the reasons of ROS abundance in certain phenotype. M1 macrophages majorly clearing the pathogens and ROS may be crucial for the regulation of M1 phenotype, whereas M2 macrophages resolve inflammation which favours oxidative metabolism. Therefore how ROS play its role in maintaining the homeostatic functions of macrophage and in particular macrophage polarization will be reviewed here. We also review the biology of macrophage polarization and the disturbance of M1/M2 balance in human diseases. The potential therapeutic opportunities targeting ROS will also be discussed, hoping to provide insights for development of target-specific delivery system or immunomodulatory antioxidant for the treatment of ROS-related diseases.

Integrin α4 Induces Lymphangiogenesis and Metastasis via Upregulation of VEGF-C in Human Colon Cancer

Vascular endothelial growth factor-C (VEGF-C) is a key regulator in lymphangiogenesis, and is overexpressed in various malignancies. Integrin α4β1, a new member of the VEGF-C/VEGF receptor pathway, was found to be overexpressed in melanoma tumors. However, little is known regarding the potential role of integrin α4β1 in lymphangiogenesis and other solid tumors. The aim of this study was to investigate the expression patterns of integrin α4 and VEGF-C in relation to lymphangiogenesis and clinicopathological parameters in human colon cancer. The expression of integrin α4, VEGF-C, and VEGFR-3 was assessed in 71 human colon cancer tissues and 30 paracancerous normal tissues by immunohistochemical staining. Lymphatic microvessel density (LMVD) was measured after D2-40-labeling, and the correlations among different factors were statistically analyzed. The expression of integrin α4, VEGF-C, VEGFR-3, and LMVD was higher in colon cancer tissues compared with the normal paracancerous colon tissues. There was a positive correlation between the expression of integrin α4 and VEGF-C. Integrin α4 and VEGF-C were significantly associated with the clinicopathological parameters (LMVD, Duke's stage, and lymph node metastasis). Kaplan-Meier analyses indicated that patients with high integrin α4 or VEGF-C expression had significantly shorter overall survival and tumor-free survival time. Multivariate analyses suggested that integrin α4 and VEGF-C may serve as independent prognostic factors for human colon cancer. Both integrin α4 and VEGF-C are involved in lymphangiogenesis and lymphatic metastasis. Our results demonstrated that integrin α4 is a novel prognostic indicator for human colon cancer. Anat Rec, 299:741-747, 2016. © 2016 Wiley Periodicals, Inc.

Macrophages: An Inflammatory Link Between Angiogenesis and Lymphangiogenesis

Angiogenesis and lymphangiogenesis often occur in response to tissue injury or in the presence of pathology (e.g., cancer), and it is these types of environments in which macrophages are activated and increased in number. Moreover, the blood vascular microcirculation and the lymphatic circulation serve as the conduits for entry and exit for monocyte-derived macrophages in nearly every tissue and organ. Macrophages both affect and are affected by the vessels through which they travel. Therefore, it is not surprising that examination of macrophage behaviors in both angiogenesis and lymphangiogenesis has yielded interesting observations that suggest macrophages may be key regulators of these complex growth and remodeling processes. In this review, we will take a closer look at macrophages through the lens of angiogenesis and lymphangiogenesis, examining how their dynamic behaviors may regulate vessel sprouting and function. We present macrophages as a cellular link that spatially and temporally connects angiogenesis with lymphangiogenesis, in both physiological growth and in pathological adaptations, such as tumorigenesis. As such, attempts to therapeutically target macrophages in order to affect these processes may be particularly effective, and studying macrophages in both settings will accelerate the field's understanding of this important cell type in health and disease.

The lymphatic system and pancreatic cancer

This review summarizes current knowledge of the biology, pathology and clinical understanding of lymphatic invasion and metastasis in pancreatic cancer. We discuss the clinical and biological consequences of lymphatic invasion and metastasis, including paraneoplastic effects on immune responses and consider the possible benefit of therapies to treat tumors that are localized to lymphatics. A review of current techniques and methods to study interactions between tumors and lymphatics is presented.

Understanding lymphangiogenesis in knockout models, the cornea, and ocular diseases for the development of therapeutic interventions

A major focus of cancer research for several decades has been understand the ability of tumors to induce new blood vessel formation, a process known as angiogenesis. Unfortunately, only limited success has been achieved in the clinical application of angiogenesis inhibitors. We now know that lymphangiogenesis, the growth of lymphatic vessels, likely also plays a major role in tumor progression. Thus, therapeutic strategies targeting lymphangiogenesis or both lymphangiogenesis and angiogenesis may represent promising approaches for treating cancer and other diseases. Importantly, research progress toward understanding lymphangiogenesis is significantly behind that related to angiogenesis. A PubMed search of "angiogenesis" returns nearly 80,000 articles, whereas a search of "lymphangiogenesis" returns 2,635 articles. This stark contrast can be explained by the lack of molecular markers for identifying the invisible lymphatic vasculature that persisted until less than 2 decades ago, combined with the intensity of research interest in angiogenesis during the past half century. Still, significant strides have been made in developing strategies to modulate lymphangiogenesis, largely using ocular disease models. Here we review the current knowledge of lymphangiogenesis in the context of knockout models, ocular diseases, the biology of activators and inhibitors, and the potential for therapeutic interventions targeting this process.

CD68+, but not stabilin-1+ tumor associated macrophages in gaps of ductal tumor structures negatively correlate with the lymphatic metastasis in human breast cancer

Tumor associated macrophages (TAM) support tumor growth and metastasis in several animal models of breast cancer, and TAM amount is predictive for efficient tumor growth and metastatic spread via blood circulation. However, limited information is available about intratumoral TAM heterogeneity and functional role of TAM subpopulations in tumor progression. The aim of our study was to examine correlation of TAM presence in various morphological segments of human breast cancer with clinical parameters. Thirty six female patients with nonspecific invasive breast cancer T1-4N0-3M0 were included in the study. Morphological examination was performed using Carl Zeiss Axio Lab.A1 and MiraxMidiZeiss. Immunohistochemical and immunofluorescence/confocal microcopy analysis was used to detect CD68 and stabilin-1 in 5 different tumor segments: (1) areas with soft fibrous stroma; (2) areas with coarse fibrous stroma; (3) areas of maximum stromal-and-parenchymal relationship; (4) parenchymal elements; (5) gaps of ductal tumor structures. The highest expression of CD68 was in areas with soft fibrous stroma or areas of maximum stromal-and-parenchymal relationship (79%). The lowest expression of CD68 was in areas with coarse fiber stroma (23%). Inverse correlation of tumor size and expression of CD68 in gaps of tubular tumor structures was found (R=-0.67; p=0.02). In case of the lymph node metastases the average score of CD68 expression in ductal gaps tumor structures was lower (1.4±0.5) compared to negative lymph nodes case (3.1±1.0; F=10.9; p=0.007). Confocal microscopy identified 3 phenotypes of TAM: CD68⁺/stabilin-1^-; CD68⁺/stabilin-1⁺ (over 50%); and CD68^-/stabilin-1⁺. However, expression of stabilin-1 did not correlate with lymph node metastasis. We concluded, that increased amount of CD68+TAM in gaps of ductal tumor structures is protective against metastatic spread in regional lymph nodes.

Vascular endothelial growth factor receptor-3 is a novel target to improve net ultrafiltration in methylglyoxal-induced peritoneal injury

Appropriate fluid balance is important for good clinical outcomes and survival in patients on peritoneal dialysis. We recently reported that lymphangiogenesis associated with fibrosis developed in the peritoneal cavity via the transforming growth factor-β1-vascular endothelial growth factor-C (VEGF-C) pathway. We investigated whether VEGF receptor-3 (VEGFR-3), the receptor for VEGF-C and -D, might be a new target to improve net ultrafiltration by using adenovirus-expressing soluble VEGFR-3 (Adeno-sVEGFR-3) in rodent models of peritoneal injury induced by methylglyoxal (MGO). We demonstrated that lymphangiogenesis developed in these MGO models, especially in the diaphragm, indicating that lymphangiogenesis is a common feature in the peritoneal cavity with inflammation and fibrosis. In MGO models, VEGF-D was significantly increased in the diaphragm; however, VEGF-C was not significantly upregulated. Adeno-sVEGFR-3, which was detected on day 50 after administration via tail vein injections, successfully suppressed lymphangiogenesis in the diaphragm and parietal peritoneum in mouse MGO models without significant effects on fibrosis, inflammation, or neoangiogenesis. Drained volume in the peritoneal equilibration test using a 7.5% icodextrin peritoneal dialysis solution (the 7.5% icodextrin peritoneal equilibration test) was improved by Adeno-sVEGFR-3 on day 22 (P<0.05) and day 50 after reduction of inflammation (P<0.01), indicating that the 7.5% icodextrin peritoneal equilibration test identifies changes in lymphangiogenesis. The solute transport rate was not affected by suppression of lymphangiogenesis. In human peritoneal dialysis patients, the dialysate to plasma ratio of creatinine positively correlated with the dialysate VEGF-D concentration (P<0.001). VEGF-D mRNA was significantly higher in the peritoneal membranes of patients with ultrafiltration failure, indicating that VEGF-D is involved in the development of lymphangiogenesis in peritoneal dialysis patients. These results indicate that VEGFR-3 is a new target to improve net ultrafiltration by suppressing lymphatic absorption and that the 7.5% icodextrin peritoneal equilibration test is useful for estimation of lymphatic absorption.

Chronic inflammation in urothelial bladder cancer

The association between inflammation and cancer has been pointed out in epidemiological and clinical studies, revealing how chronic inflammation may contribute to carcinogenesis in various malignancies. However, the molecular events leading to malignant transformation in a chronically inflamed environment are not fully understood. In urothelial carcinoma of the urinary bladder, inflammation plays a dual role. On the one hand, chronic inflammation is a well-established risk factor for the development of bladder cancer (BC), as seen in Schistosoma haematobium infection. On the other, intravesical therapy by bacillus Calmette-Guérin (BCG), which induces inflammation, offers protection against cancer recurrence. The large variety of pro-inflammatory mediators expressed by BC and immune cells binds to specific receptors which control signalling pathways. These activate transcription of a plethora of downstream factors. This review summarizes recent data regarding inflammation and urothelial carcinoma, with special emphasis on the role the inflammatory response plays in BC recurrence risk and progression.

VEGFR3 inhibition chemosensitizes ovarian cancer stemlike cells through down-regulation of BRCA1 and BRCA2

In ovarian cancer, loss of BRCA gene expression in tumors is associated with improved response to chemotherapy and increased survival. A means to pharmacologically downregulate BRCA gene expression could improve the outcomes of patients with BRCA wild-type tumors. We report that vascular endothelial growth factor receptor 3 (VEGFR3) inhibition in ovarian cancer cells is associated with decreased levels of both BRCA1 and BRCA2. Inhibition of VEGFR3 in ovarian tumor cells was associated with growth arrest. CD133(+) ovarian cancer stemlike cells were preferentially susceptible to VEGFR3-mediated growth inhibition. VEGFR3 inhibition-mediated down-regulation of BRCA gene expression reversed chemotherapy resistance and restored chemosensitivity in resistant cell lines in which a BRCA2 mutation had reverted to wild type. Finally, we demonstrate that tumor-associated macrophages are a primary source of VEGF-C in the tumor microenvironment. Our studies suggest that VEGFR3 inhibition may be a pharmacologic means to downregulate BRCA genes and improve the outcomes of patients with BRCA wild-type tumors.

Pharmacokinetic, Pharmacodynamic, and Activity Evaluation of TMX-101 in a Multicenter Phase 1 Study in Patients With Papillary Non-Muscle-Invasive Bladder Cancer

INTRODUCTION/BACKGROUND

Non-muscle-invasive bladder cancer (NMIBC) has a strong tendency to recur despite adjuvant instillations. TMX-101 is a new liquid form of imiquimod for intravesical instillation and has activity in vitro against urothelial carcinoma. The purpose was to analyze the activity of TMX-101 in low-grade NMIBC. Furthermore, pharmacokinetic and pharmacodynamic characteristics and adverse events were evaluated.

PATIENTS AND METHODS

A multicenter, prospective phase 1 trial in 7 patients with low-grade NMIBC was conducted. All patients underwent a marker lesion transurethral resection of the bladder tumor and 6 weekly instillations with TMX-101 0.2% or 0.4%. Cystoscopy 2 to 4 weeks after the last instillation evaluated the effect of TMX-101.

RESULTS

The effective biologic dose (EBD = complete response [CR] in > 2 patients) could not be defined because none of the patients experienced CR. Maximum plasma concentration was 75.1 ng/mL in the 0.4% dose group. No drug accumulation was observed. In the pharmacodynamic analysis, urinary interleukin 1 receptor agonist (IL-1ra) represents the most sensitive and uniform response after TMX-101 instillation. A total of 87.0% reported at least 1 adverse event. All events were of grade 2 severity or less (Common Terminology Criteria of Adverse Events version 4.02). No clinically significant changes in laboratory parameters or vital signs were observed during or after treatment.

CONCLUSION

Toll-like receptor 7 (TLR-7) agonists are effective in urothelial carcinoma in preclinical research. The EBD in this phase 1 study could not be determined because no patient experienced CR. IL-1ra could be valuable as a urinary biomarker in future developments. The safety of TMX-101 has been reconfirmed. New doses, other schedules, and NMIBC subgroups should be tested to define the EBD. A pilot study in carcinoma-in-situ patients is currently ongoing and results are expected shortly.