Immune cells regulate VEGF signalling via release of VEGF and antagonistic soluble VEGF receptor-1

Immunoregulation mechanism of VEGF signaling pathway inhibitors and its efficacy on the kidney

Angiogenesis and immunosuppression are closely related pathophysiologic processes. Widely prescribed in malignant tumor and proliferative retinal lesions, VEGF signaling pathway inhibitors may cause hypertension and renal injury in some patients, presenting with proteinuria, nephrotic syndrome, renal failure and thrombotic microangiopathy. VEGF signaling pathway inhibitors block the action of both VEGF-A and VEGF-C. However, VEGF-A and VEGF-C produced by podocytes are vital to maintain the physiological function of glomerular endothelial cells and podocytes. There is still no effective treatment for kidney disease associated with VEGF signaling pathway inhibitors and some patients have progressive renal failure even after withdrawal of the drug. Recent studies reveal that blocking of VEGF-A and VEGF-C can activate CD4 +and CD8+ T cells, augment antigen-presenting function of dendritic cells, enhance cytotoxicity of macrophages and initiate complement cascade activation. VEGF and VEGFR are expressed in immune cells, which are involved in the immunosuppression and cross-talk among immune cells. This review summarizes the expression and function of VEGF-A and VEGF-C in the kidney. The current immunoregulation mechanisms of VEGF signaling pathway inhibitors are reviewed. Finally, combinate strategies are summarized to highlight the proposal for VEGF signaling pathway inhibitors.

The role of angiogenic growth factors in the immune microenvironment of glioma

Angiogenic growth factors (AGFs) are a class of secreted cytokines related to angiogenesis that mainly include vascular endothelial growth factors (VEGFs), stromal-derived factor-1 (SDF-1), platelet-derived growth factors (PDGFs), fibroblast growth factors (FGFs), transforming growth factor-beta (TGF-β) and angiopoietins (ANGs). Accumulating evidence indicates that the role of AGFs is not only limited to tumor angiogenesis but also participating in tumor progression by other mechanisms that go beyond their angiogenic role. AGFs were shown to be upregulated in the glioma microenvironment characterized by extensive angiogenesis and high immunosuppression. AGFs produced by tumor and stromal cells can exert an immunomodulatory role in the glioma microenvironment by interacting with immune cells. This review aims to sum up the interactions among AGFs, immune cells and cancer cells with a particular emphasis on glioma and tries to provide new perspectives for understanding the glioma immune microenvironment and in-depth explorations for anti-glioma therapy.

The role of VEGF in cancer-induced angiogenesis and research progress of drugs targeting VEGF

Angiogenesis is a double-edged sword; it is a mechanism that defines the boundary between health and disease. In spite of its central role in physiological homeostasis, it provides the oxygen and nutrition needed by tumor cells to proceed from dormancy if pro-angiogenic factors tip the balance in favor of tumor angiogenesis. Among pro-angiogenic factors, vascular endothelial growth factor (VEGF) is a prominent target in therapeutic methods due to its strategic involvement in the formation of anomalous tumor vasculature. In addition, VEGF exhibits immune-regulatory properties which suppress immune cell antitumor activity. VEGF signaling through its receptors is an integral part of tumoral angiogenic approaches. A wide variety of medicines have been designed to target the ligands and receptors of this pro-angiogenic superfamily. Herein, we summarize the direct and indirect molecular mechanisms of VEGF to demonstrate its versatile role in the context of cancer angiogenesis and current transformative VEGF-targeted strategies interfering with tumor growth.

Landscape of Well-Coordinated Fracture Healing in a Mouse Model Using Molecular and Cellular Analysis

The success of fracture healing relies on overlapping but coordinated cellular and molecular events. Characterizing an outline of differential gene regulation throughout successful healing is essential for identifying crucial phase-specific markers and may serve as the basis for engineering these in challenging healing situations. This study analyzed the healing progression of a standard closed femoral fracture model in C57BL/6N (age = 8 weeks) wild-type male mice. The fracture callus was assessed across various days post fracture (D = days 0, 3, 7, 10, 14, 21, and 28) by microarray, with D0 serving as a control. Histological analyses were carried out on samples from D7 until D28 to support the molecular findings. Microarray analysis revealed a differential regulation of immune response, angiogenesis, ossification, extracellular matrix regulation, mitochondrial and ribosomal genes during healing. In-depth analysis showed differential regulation of mitochondrial and ribosomal genes during the initial phase of healing. Furthermore, the differential gene expression showed an essential role of Serpin Family F Member 1 over the well-known Vascular Endothelial Growth Factor in angiogenesis, especially during the inflammatory phase. The significant upregulation of matrix metalloproteinase 13 and bone sialoprotein from D3 until D21 asserts their importance in bone mineralization. The study also shows type I collagen around osteocytes located in the ossified region at the periosteal surface during the first week of healing. Histological analysis of matrix extracellular phosphoglycoprotein and extracellular signal-regulated kinase stressed their roles in bone homeostasis and the physiological bone-healing process. This study reveals previously unknown and novel candidates, that could serve as a target for specific time points in healing and to remedy cases of impaired healing.

The roles of metabolic profiles and intracellular signaling pathways of tumor microenvironment cells in angiogenesis of solid tumors

Innate and adaptive immune cells patrol and survey throughout the human body and sometimes reside in the tumor microenvironment (TME) with a variety of cell types and nutrients that may differ from those in which they developed. The metabolic pathways and metabolites of immune cells are rooted in cell physiology, and not only provide nutrients and energy for cell growth and survival but also influencing cell differentiation and effector functions. Nowadays, there is a growing awareness that metabolic processes occurring in cancer cells can affect immune cell function and lead to tumor immune evasion and angiogenesis. In order to safely treat cancer patients and prevent immune checkpoint blockade-induced toxicities and autoimmunity, we suggest using anti-angiogenic drugs solely or combined with Immune checkpoint blockers (ICBs) to boost the safety and effectiveness of cancer therapy. As a consequence, there is significant and escalating attention to discovering techniques that target metabolism as a new method of cancer therapy. In this review, a summary of immune-metabolic processes and their potential role in the stimulation of intracellular signaling in TME cells that lead to tumor angiogenesis, and therapeutic applications is provided. Video abstract.

Vincristine-doxorubicin co-loaded artificial low-density lipoproteins towards solid tumours

To construct an artificial low-density lipoprotein (aLDL) that highly mimics low-density lipoprotein (LDL) in vivo, and deliver vincristine (VCR) - doxorubicin (DOX) simultaneously, the 100 nm and 35 nm DOX-VCR-aLDLs (DV-aLDLs) were constructed, then the physicochemical characteristics were evaluated. Through in vitro inverse gravity diffusion experiment, the tumour cake and sphere model experiment, draw a conclusion that the diffusion of 35 nm DV-aLDLs was stronger than 100 nm DV-aLDLs, and the tumour retention of 35 nm DV-aLDLs was better than the DV-solution. In addition, the three-dimension (3D) in vivo distribution imaging of aLDLs was performed on HepG-2 tumour-bearing nude mice, followed by the biodistribution and therapeutic efficacy on these xenograft models. Taking advantage of better diffusion capacity in tumour tissue, as well as the synergistic effect of VCR and DOX, the 35 nm DV-aLDL had the strongest efficacy and the lowest toxicity. High entrapment efficiency and stability, both active and passive targeting, making aLDL a potential carrier for tumour-targeted therapy at the same time.

Curcumin in Combination With Omacetaxine Suppress Lymphoma Cell Growth, Migration, Invasion, and Angiogenesis via Inhibition of VEGF/Akt Signaling Pathway

Background

Both omacetaxine (HHT) and curcumin were shown to exhibit anti-proliferative effect on lymphoma cells. However, the role of combination of HHT with curcumin (HHT/curcumin combination) on lymphoma cells remains unclear. Thus, this study aimed to investigate the effect of HHT/curcumin combination on the proliferation, migration, and angiogenesis of lymphoma cells.

Methods

Cell counting kit-8 (CCK-8), Ki67 immunofluorescence and transwell assays were used to assess the viability, proliferation and migration of U937 and Raji cells respectively. In addition, tube formation assay was used to determine the effects of HHT/curcumin combination on angiogenesis in human umbilical vein endothelial cells (HUVECs).

Results

In this study, we found that HHT/curcumin combination significantly inhibited the proliferation, migration and invasion in U937 and Raji cells (all P < 0.01). In addition, combination treatment markedly inhibited the secreted levels of vascular endothelial growth factor (VEGF)-(A-D) (all P < 0.01) in Raji cells. Moreover, combination treatment exhibited anti-tumor effects in Raji cells, as shown by the decreased signals of phosphorylated VEGF receptor 2 (p-VEGFR2) and phosphorylated protein kinase B (p-Akt) (all P < 0.01). Meanwhile, combination treatment inhibited VEGFA levels (P < 0.01) in exosomes derived from Raji cells. Application of exosomes with downregulated VEGF to HUVECs notably inhibited proliferation, migration and tube formation of HUVECs, evidenced by the decreased signals of p-Akt, angiogenin-1, matrix metallopeptidase 2 (MMP2) and matrix metallopeptidase 9 (MMP9) (all P < 0.01).

Conclusion

Our findings indicated that combination of HHT and curcumin could inhibit lymphoma cell growth and angiogenesis via inhibition of VEGF/Akt signaling pathway. These results suggested that HHT combined with curcumin might be regarded as a promising therapeutic approach for the treatment of lymphoma.

Autologous CXCR4+ Hematopoietic Stem Cells Injected into the Scar Tissue of Chronic Myocardial Infarction Patients Normalizes Tissue Contractility and Perfusion

BACKGROUND

Chronic myocardial infarction (CMI), represents a public health and a financial burden. Since stem cell transplant is used to regenerate cardiac tissue after acute myocardial infarction.

AIM OF THE STUDY

To determine if autologous CXCR4 stem cells could restore damaged myocardial tissue in patients with CMI lesions.

METHODS

20 NYHA grade III male patients with CMI defined by clinical, biochemical, ECG and echocardiographic parameters were included. Patients were treated with G-CSF for 6 d before isolating their autologous stem cells from PBMCs. Cell phenotyping was done by cytofluorometry using monoclonal antibodies (anti-CXCR4, -CD34, -48, -117, -133, -Ki67, -SDF1 and CXCR4); CXCR4 cell subpopulations isolated by sorting were adjusted to 1 × 10⁸ cells by subpopulation and injected in a circular pattern into the cicatrix previously defined by echocardiography.

RESULTS

Patients were followed for 6 and 12 months. Six months after cell implant improvements in left ventricle ejection fraction (from 33-50%), stress rate values (from -3/-9% to -18/-22%), stress tests (from 4-12 METS), and the quantity of left ventricle affected segments (3-9) disappeared according to the G-SPECT images. 12 months evaluations did not show significant differences. Interestingly, 3 months after cell implant the ECG showed normal electrical activity in 9 patients whereas after 6 months it was normal in all the patients.

CONCLUSIONS

These results ratify that locally injected autologous CXCR4+ bone marrow-derived stem cells have a physiological and a clinical impact in patients with CMI.

Predictive effect of exhaled NO and VEGF expression levels on the severity of bronchial asthma and airway inflammation

OBJECTIVE

To investigate the relationship between exhaled NO and vascular endothelial growth factor (VEGF) expression in bronchial asthma patients with asthma severity and airway inflammation.

METHODS

From January 2015 to December 2017, 260 patients with bronchial asthma diagnosed in our hospital were enrolled. The expression of VEGF in the induced sputum was measured by enzyme-linked immunosorbent assay (ELISA) in the control (n=260) and asthma groups (n=260) in the same period. The NO concentration was measured on the same day.

RESULTS

Intercellular adhesion molecule-1 (ICAM-1), VEGF, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were significantly elevated in sputum of patients with acute asthma, and the concentration in exhaled NO of all patients was also significantly higher than the control group and the stable phase of asthma. The expression of ICAM-1, VEGF, TNF-α and IL-6 was significantly elevated in patients with severe asthma. There were significant differences in patients with mild to moderate asthma (P<0.05). Correlation analysis showed that VEGF, IL-6 and TNF-α were positively correlated with the degree of asthma (P<0.05), but negatively correlated with FEV1.0, FEV1.0/FVC% and PEF (P<0.05).

CONCLUSION

The expression of VEGF in sputum in patients with bronchial asthma is closely related to the severity of asthma and airway inflammation.

Cross talk between natural killer cells and mast cells in tumor angiogenesis

Natural killer (NK) cells are large granular lymphocytes of the innate immune system, responsible for direct targeting and killing of both virally infected and transformed cells. Under pathological conditions and during inflammation, NK cells extravasate into the lymph nodes and accumulate at inflammatory or tumor sites. The activation of NK cells depends on an intricate balance between activating and inhibitory signals that determines if a target will be susceptible to NK-mediated lysis. Many experimental evidences indicate that NK cells are also involved in several immunoregulatory processes and have the ability to modulate the adaptive immune responses. Many other important aspects about NK cell biology are emerging in these last years. The aim of this review is to elucidate the role of NK cells in tumor angiogenesis and their interaction with mast cells. In fact, it has been observed that NK cells produce pro-angiogenic factors and participate alone or in cooperation with mast cells to the regulation of angiogenesis in both physiological and pathological conditions including tumors.

Improving the Efficiency of Vγ9Vδ2 T-Cell Immunotherapy in Cancer

Increasing immunological knowledge and advances in techniques lay the ground for more efficient and broader application of immunotherapies. gamma delta (γδ) T-cells possess multiple favorable anti-tumor characteristics, making them promising candidates to be used in cellular and combination therapies of cancer. They recognize malignant cells, infiltrate tumors, and depict strong cytotoxic and pro-inflammatory activity. Here, we focus on human Vγ9Vδ2 T-cells, the most abundant γδ T-cell subpopulation in the blood, which are able to inhibit cancer progression in various models in vitro and in vivo. For therapeutic use they can be cultured and manipulated ex vivo and in the following adoptively transferred to patients, as well as directly stimulated to propagate in vivo. In clinical studies, Vγ9Vδ2 T-cells repeatedly demonstrated a low toxicity profile but hitherto only the modest therapeutic efficacy. This review provides a comprehensive summary of established and newer strategies for the enhancement of Vγ9Vδ2 T-cell anti-tumor functions. We discuss data of studies exploring methods for the sensitization of malignant cells, the improvement of recognition mechanisms and cytotoxic activity of Vγ9Vδ2 T-cells. Main aspects are the tumor cell metabolism, antibody-dependent cell-mediated cytotoxicity, antibody constructs, as well as activating and inhibitory receptors like NKG2D and immune checkpoint molecules. Several concepts show promising results in vitro, now awaiting translation to in vivo models and clinical studies. Given the array of research and encouraging findings in this area, this review aims at optimizing future investigations, specifically targeting the unanswered questions.

Contribution to Tumor Angiogenesis From Innate Immune Cells Within the Tumor Microenvironment: Implications for Immunotherapy

The critical role of angiogenesis in promoting tumor growth and metastasis is strongly established. However, tumors show considerable variation in angiogenic characteristics and in their sensitivity to antiangiogenic therapy. Tumor angiogenesis involves not only cancer cells but also various tumor-associated leukocytes (TALs) and stromal cells. TALs produce chemokines, cytokines, proteases, structural proteins, and microvescicles. Vascular endothelial growth factor (VEGF) and inflammatory chemokines are not only major proangiogenic factors but are also immune modulators, which increase angiogenesis and lead to immune suppression. In our review, we discuss the regulation of angiogenesis by innate immune cells in the tumor microenvironment, specific features, and roles of major players: macrophages, neutrophils, myeloid-derived suppressor and dendritic cells, mast cells, γδT cells, innate lymphoid cells, and natural killer cells. Anti-VEGF or anti-inflammatory drugs could balance an immunosuppressive microenvironment to an immune permissive one. Anti-VEGF as well as anti-inflammatory drugs could therefore represent partners for combinations with immune checkpoint inhibitors, enhancing the effects of immune therapy.