The Complexity of Translating Anti-angiogenesis Therapy from Basic Science to the Clinic

VEGF-induced Nrdp1 deficiency in vascular endothelial cells promotes cancer metastasis by degrading vascular basement membrane

Vascular endothelial cells (VECs) are key players in the formation of neovessels and tumor metastasis, the ultimate cause of the majority of cancer-related human death. However, the crosstalk between VECs and metastasis remain greatly elusive. Based on our finding that tumor-associated VECs present significant decrease of Nrdp1 protein which is closely correlated with higher metastatic probability, herein we show that the conditional medium from hypoxia-incubated cancer cells induces extensive Nrdp1 downregulation in human and mouse VECs by vascular endothelial growth factor (VEGF), which activates CHIP, followed by Nrdp1 degradation in ubiquitin-proteasome-dependent way. More importantly, lung metastases of cancer cells significantly increase in conditional VECs Nrdp1 knockout mice. Mechanically, Nrdp1 promotes degradation of Fam20C, a secretory kinase involved in phosphorylating numerous secreted proteins. Reciprocally, deficiency of Nrdp1 in VECs (ecNrdp1) results in increased secretion of Fam20C, which induces degradation of extracellular matrix and disrupts integrity of vascular basement membrane, thus driving tumor metastatic dissemination. In addition, specific overexpression of ecNrdp1 by Nrdp1-carrying adeno-associated virus or chemical Nrdp1 activator ABPN efficiently mitigates tumor metastasis in mice. Collectively, we explore a new mechanism for VEGF to enhance metastasis and role of Nrdp1 in maintaining the integrity of vascular endothelium, suggesting that ecNrdp1-mediated signaling pathways might become potential target for anti-metastatic therapies.

Discovery of a Dual Tubulin and Neuropilin-1 (NRP1) Inhibitor with Potent In Vivo Anti-Tumor Activity via Pharmacophore-based Docking Screening, Structure Optimization, and Biological Evaluation

Dual inhibition of tubulin and neuropilin-1 (NRP1) may become an effective method for cancer treatment by simultaneously killing tumor cells and inhibiting tumor angiogenesis. Herein, we identified dual tubulin/NRP1-targeting inhibitor TN-2, which exhibited good inhibitory activity against both tubulin polymerization (IC50 = 0.71 ± 0.03 μM) and NRP1 (IC50 = 0.85 ± 0.04 μM). Importantly, it significantly inhibited the viability of several human prostate tumor cell lines. Further mechanism studies indicated that TN-2 could inhibit tubulin polymerization and cause G2/M arrest, thereby inducing cell apoptosis. It could also suppress cell tube formation, migration, and invasion. Moreover, TN-2 showed obvious antitumor effects on the PC-3 cell-derived xenograft model with negligible side effects and good pharmacokinetic profiles. These data demonstrate that TN-2 could be a promising dual-target chemotherapeutic agent for the treatment of prostate cancer.

Advances in targeted therapy and immunotherapy for melanoma (Review)

Melanoma is the most aggressive and deadly type of skin cancer and is known for its poor prognosis as soon as metastasis occurs. Since 2011, new and effective therapies for metastatic melanoma have emerged, with US Food and Drug Administration approval of multiple targeted agents, such as V-Raf murine sarcoma viral oncogene homolog B1/mitogen-activated protein kinase kinase inhibitors and multiple immunotherapy agents, such as cytotoxic T lymphocyte-associated protein 4 and anti-programmed cell death protein 1/ligand 1 blockade. Based on insight into the respective advantages of the above two strategies, the present article provided a review of clinical trials of the application of targeted therapy and immunotherapy, as well as novel approaches of their combinations for the treatment of metastatic melanoma in recent years, with a focus on upcoming initiatives to improve the efficacy of these treatment approaches for metastatic melanoma.

CXCL10 mediates CD8+ T cells to facilitate vessel normalization and improve the efficacy of cetuximab combined with PD-1 checkpoint inhibitors in colorectal cancer

The immunotherapy and anti-EGFR targeted treatment occupying a pivotal position in colorectal cancer (CRC), is still limited to a group of patients who display specific molecular alterations and inevitably escape from resistance, further studies are still needed in colorectal cancer. We found that chemokine ligand 10 (CXCL10) expression correlates with intratumoral CD8⁺ T cell infiltration and reprograms tumor vasculatures in colorectal cancer. CXCL10 overexpression not only suppressed tumor growth but also increased CD8⁺ T cell infiltration and induced tumor vascular normalization in vivo. Additionally, the growth inhibition and tumor vascular normalization induced by CXCL10 can be reversed by the depletion of CD8⁺ T cells in vivo. Mechanically, CXCL10 interacts with VCAN to mediate tumor vascular normalization. The VCAN expression correlated inversely with the expression of CXCL10 and the infiltration of CD8⁺ T cells in CRC. Elevated CXCL10 expression sensitized colorectal cancer cells to cetuximab/anti-PD1 combination therapy compared with cetuximab or anti-PD1 alone. We propose that CXCL10 could be used to increase the anti-EGFR therapy and immunotherapy effect, targeting both tumor vessels and immune cells in colorectal cancer.

The application and research progress of anti-angiogenesis therapy in tumor immunotherapy

Tumor immunotherapy, as the focus of scientific research and clinical tumor treatment in recent years, has received extensive attention. Due to its remarkable curative effect and fewer side effects than traditional treatments, it has significant clinical benefits for the treatment of various advanced cancers and can improve cancer patient survival in the long term. Currently, most patients cannot benefit from immunotherapy, and some patients may experience tumor recurrence and drug resistance even if they achieve remission overcome. Numerous studies have shown that the abnormal angiogenesis state of tumors can lead to immunosuppressive tumor microenvironment, which affects the efficacy of immunotherapy. Actually, to improve the efficacy of immunotherapy, the application of anti-angiogenesis drugs to normalize abnormal tumor vessel has been widely confirmed in basic and clinical research. This review not only discusses the risk factors, mechanisms, and effects of abnormal and normalized tumor angiogenesis state on the immune environment, but summarizes the latest progress of immunotherapy combined with anti-angiogenic therapy. We hope this review provides an applied reference for anti-angiogenesis drugs and synergistic immunotherapy therapy.

ASPSCR1::TFE3 orchestrates the angiogenic program of alveolar soft part sarcoma

Alveolar soft part sarcoma (ASPS) is a soft part malignancy affecting adolescents and young adults. ASPS is characterized by a highly integrated vascular network, and its high metastatic potential indicates the importance of ASPS's prominent angiogenic activity. Here, we find that the expression of ASPSCR1::TFE3, the fusion transcription factor causatively associated with ASPS, is dispensable for in vitro tumor maintenance; however, it is required for in vivo tumor development via angiogenesis. ASPSCR1::TFE3 is frequently associated with super-enhancers (SEs) upon its DNA binding, and the loss of its expression induces SE-distribution dynamic modification related to genes belonging to the angiogenesis pathway. Using epigenomic CRISPR/dCas9 screening, we identify Pdgfb, Rab27a, Sytl2, and Vwf as critical targets associated with reduced enhancer activities due to the ASPSCR1::TFE3 loss. Upregulation of Rab27a and Sytl2 promotes angiogenic factor-trafficking to facilitate ASPS vascular network construction. ASPSCR1::TFE3 thus orchestrates higher ordered angiogenesis via modulating the SE activity.

Apelin Receptor Can Act as a Specific Marker and Promising Therapeutic Target for Infantile Hemangioma

Infantile hemangioma (IH), the most common benign tumor in infancy, is generally sensitive to propranolol treatment. However, the challenge remains because resistance or recurrence could occur in some patients, and the mechanism or target of propranolol remains unknown. Therefore, advancement in the drug development is needed. In this study, we explored whether apelin receptor (APJ) can become a candidate target. We found that APJ is expressed only in endothelial cells of IH (HemECs) but not in other vascular anomalies, and its antagonist, ML221, can negatively regulate cellular viability and functions of HemECs. This inhibitory effect could be replicated in a murine hemangioma model. Importantly, in vitro experiments also indicated that ML221 failed to affect the proliferation or angiogenesis of normal endothelial cells or APJ-knockout HemECs. Through analysis of the phosphoantibody microarray data, ML221 was revealed to have an inhibitory effect on HemECs by suppressing the activation of mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. These results verified the distinctive expression of APJ in IH and specific inhibition of HemEC activity caused by ML221. In addition, APJ was also detected in propranolol-resistant IH. Collectively, we propose that APJ can act as a specific marker and a promising therapeutic target for IH, which will facilitate further drug development.

Luteolin Suppresses Three Angiogenesis Modes and Cell Interaction in Uveal Melanoma in Vitro

PURPOSE

Uveal melanoma is a high-vascularized tumor that lacks effective systemic therapies. Most anti-angiogenesis drug therapies only target endothelial cell-dependent angiogenesis but not vasculogenic mimicry (VM), which supplies blood to tumors independent of endothelial cells. Thus, we aimed to explore the inhibitory effects of luteolin on proliferation, migration, invasiveness, angiogenesis, and VM activity of uveal melanoma. We further explored the signaling pathway underlying the mechanism of action of luteolin.

METHODS

Monocultures of uveal melanoma C918 cells, human umbilical vein endothelial cells (HUVECs), and co-cultures of these two cell lines were established. Angiogenesis of HUVECs, VM formation of C918 cells, and the mosaic vessels formed by both cell types were observed under an inverted microscope. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), wound scratch, Transwell cell migration, and invasion assays were performed. VEGF levels were detected by ELISA. Western blotting was used to detect the expression of PI3K, p-PI3K P85, Akt, and p-Akt Ser473 proteins.

RESULTS

Luteolin inhibited all three modes of angiogenesis observed in uveal melanoma in vitro. Luteolin effectively inhibited the proliferation, migration, and invasion of C918 cells and proliferation and migration of HUVECs. Furthermore, luteolin could inhibit the interaction between the endothelial cells and C918 cells. VEGF secretion in C918 cells and HUVECs treated with luteolin was inhibited. Luteolin decreased the levels of phosphorylated Akt kinase.

CONCLUSION

We demonstrated the anti-angiogenic effects of luteolin, including against the VM type, in addition to suppressing tumor cell proliferation and migration in vitro. Furthermore, luteolin likely exerts its inhibitory effects via the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Luteolin might be an effective therapeutic candidate for treating highly vascularized uveal melanoma tumors.

Vascular Disruptive Hydrogel Platform for Enhanced Chemotherapy and Anti-Angiogenesis through Alleviation of Immune Surveillance

Patients undergoing immunotherapy always exhibit a low-response rate due to tumor heterogeneity and immune surveillance in the tumor. Angiogenesis plays an important role in affecting the status of tumor-infiltrated lymphocytes by inducing hypoxia and acidosis microenvironment, suggesting its synergistic potential in immunotherapy. However, the antitumor efficacy of singular anti-angiogenesis therapy often suffers from failure in the clinic due to the compensatory pro-angiogenesis signaling pathway. In this work, classic injectable thermosensitive PLGA-PEG-PLGA copolymer was used to construct a platform to co-deliver CA4P (vascular disruptive agent) and EPI for inducing immunogenic cell death of cancer cells by targeting the tumor immune microenvironment. Investigation of 4T1 tumor-bearing mouse models suggests that local administration of injectable V+E@Gel could significantly inhibit the proliferation of cancer cells and prolong the survival rate of 4T1 tumor-bearing mouse models. Histological analysis further indicates that V+E@Gel could effectively inhibit tumor angiogenesis and metastasis by down-regulating the expression of CD34, CD31, MTA1 and TGF-β. Moreover, due to the sustained release kinetics of V+E@Gel, its local administration relieves the immune surveillance in tumor tissues and thus induces a robust and long-lasting specific antitumor immune response. Overall, this work provides a new treatment strategy through the mediation of the tumor immune microenvironment by vascular disruption to fulfill enhanced chemotherapy and immunotherapy.

Treatment with a VEGFR-2 antibody results in intra-tumor immune modulation and enhances anti-tumor efficacy of PD-L1 blockade in syngeneic murine tumor models

Prolonged activation of vascular endothelial growth factor receptor-2 (VEGFR-2) due to mis-regulation of the VEGF pathway induces aberrant blood vessel expansion, which supports growth and survival of solid tumors. Therapeutic interventions that inhibit the VEGFR-2 pathway have therefore become a mainstay of cancer treatment. Non-clinical studies have recently revealed that blockade of angiogenesis can modulate the tumor microenvironment and enhance the efficacy of concurrent immune therapies. Ramucirumab is an FDA-approved anti-angiogenic antibody that inhibits VEGFR-2 and is currently being evaluated in clinical studies in combination with anti-programmed cell death (PD-1) axis checkpoint inhibitors (pembrolizumab, durvalumab, or sintilimab) across several cancer types. The purpose of this study is to establish a mechanistic basis for the enhanced activity observed in the combined blockade of VEGFR-2 and PD-1-axis pathways. Pre-clinical studies were conducted in murine tumor models known to be responsive to anti-PD-1 axis therapy, using monoclonal antibodies that block mouse VEGFR-2 and programmed death-ligand 1 (PD-L1). Combination therapy resulted in enhanced anti-tumor activity compared to anti-PD-L1 monotherapy. VEGFR-2 blockade at early timepoints post-anti-PD-L1 therapy resulted in a dose-dependent and transient enhanced infiltration of T cells, and establishment of immunological memory. VEGFR-2 blockade at later timepoints resulted in enhancement of anti-PD-L1-driven immune cell infiltration. VEGFR-2 and PD-L1 monotherapies induced both unique and overlapping patterns of immune gene expression, and combination therapy resulted in an enhanced immune activation signature. Collectively, these results provide new and actionable insights into the mechanisms by which concurrent VEGFR-2 and PD-L1 antibody therapy leads to enhanced anti-tumor efficacy.

STAT3-YAP/TAZ signaling in endothelial cells promotes tumor angiogenesis

[Figure: see text].

Endothelial deletion of SHP2 suppresses tumor angiogenesis and promotes vascular normalization

SHP2 mediates the activities of multiple receptor tyrosine kinase signaling and its function in endothelial processes has been explored extensively. However, genetic studies on the role of SHP2 in tumor angiogenesis have not been conducted. Here, we show that SHP2 is activated in tumor endothelia. Shp2 deletion and pharmacological inhibition reduce tumor growth and microvascular density in multiple mouse tumor models. Shp2 deletion also leads to tumor vascular normalization, indicated by increased pericyte coverage and vessel perfusion. SHP2 inefficiency impairs endothelial cell proliferation, migration, and tubulogenesis through downregulating the expression of proangiogenic SRY-Box transcription factor 7 (SOX7), whose re-expression restores endothelial function in SHP2-knockdown cells and tumor growth, angiogenesis, and vascular abnormalization in Shp2-deleted mice. SHP2 stabilizes apoptosis signal-regulating kinase 1 (ASK1), which regulates SOX7 expression mediated by c-Jun. Our studies suggest SHP2 in tumor associated endothelial cells is a promising anti-angiogenic target for cancer therapy.

Targeting the Microenvironment in Esophageal Cancer

Esophageal cancer (EC) is the eighth most common type of cancer and the sixth leading cause of cancer-related deaths worldwide. At present, the clinical treatment for EC is based mainly on radical surgery, chemotherapy, and radiotherapy. However, due to the limited efficacy of conventional treatments and the serious adverse reactions, the outcome is still unsatisfactory (the 5-year survival rate for patients is less than 25%). Thus, it is extremely important and urgent to identify new therapeutic targets. The concept of tumor microenvironment (TME) has attracted increased attention since it was proposed. Recent studies have shown that TME is an important therapeutic target for EC. Microenvironment-targeting therapies such as immunotherapy and antiangiogenic therapy have played an indispensable role in prolonging survival and improving the prognosis of patients with EC. In addition, many new drugs and therapies that have been developed to target microenvironment may become treatment options in the future. We summarize the microenvironment of EC and the latest advances in microenvironment-targeting therapies in this review.

Alkylating Agents, the Road Less Traversed, Changing Anticancer Therapy

Cancer is considered one of the gruelling challenges and poses a grave health hazard across the globe. According to the International Agency for Research on Cancer (IARC), new cancer diagnoses increased to 18.1 million in 2018, with 9.6 million deaths, bringing the global cancer rate to 23.6 million by 2030. In 1942, the discovery of nitrogen mustard as an alkylating agent was a tremendous breakthrough in cancer chemotherapy. It acts by binding to the DNA, and creating cross linkages between the two strands, leading to arrest of DNA replication and eventual cell death. Nitrogen lone pairs of 'nitrogen mustard' produce an intermediate 'aziridinium ion' at molecular level, which is very reactive towards DNA of tumour cells, resulting in multiple side effects with therapeutic consequences. Owing to its high reactivity and peripheral cytotoxicity, several improvements have been made with structural modifications for the past 75 years to enhance its efficacy and improve the direct transport of drugs to the tumour cells. Alkylating agents were among the first non-hormonal substances proven to be active against malignant cells and also, the most valuable cytotoxic therapies available for the treatment of leukaemia and lymphoma patients. This review focus on the versatile use of alkylating agents and the structure activity relationship (SAR) of each class of these compounds. This could provide an understanding for design and synthesis of new alkylating agents having enhanced target specificity and adequate bioavailability.

Three-dimensional CRISPR screening reveals epigenetic interaction with anti-angiogenic therapy

Angiogenesis underlies development, physiology and pathogenesis of cancer, eye and cardiovascular diseases. Inhibiting aberrant angiogenesis using anti-angiogenic therapy (AAT) has been successful in the clinical treatment of cancer and eye diseases. However, resistance to AAT inevitably occurs and its molecular basis remains poorly understood. Here, we uncover molecular modifiers of the blood endothelial cell (EC) response to a widely used AAT bevacizumab by performing a pooled genetic screen using three-dimensional microcarrier-based cell culture and CRISPR–Cas9. Functional inhibition of the epigenetic reader BET family of proteins BRD2/3/4 shows unexpected mitigating effects on EC survival and/or proliferation upon VEGFA blockade. Moreover, transcriptomic and pathway analyses reveal an interaction between epigenetic regulation and anti-angiogenesis, which may affect chromosomal structure and activity in ECs via the cell cycle regulator CDC25B phosphatase. Collectively, our findings provide insight into epigenetic regulation of the EC response to VEGFA blockade and may facilitate development of quality biomarkers and strategies for overcoming resistance to AAT.

Through three-dimensional CRISPR screening, He et al. report that functional inhibition of BET family of proteins BRD2/3/4 shows mitigating effects on blood endothelial cell (EC) survival and/or proliferation upon VEGFA blockade. An interaction between epigenetic regulation and anti-angiogenesis, which may affect chromosomal structure and activity in ECs through CDC25B phosphatase, is potentially involved with EC resistance to anti-angiogenic therapy.

Dual role of endothelial Myct1 in tumor angiogenesis and tumor immunity

The cross-talk between angiogenesis and immunity within the tumor microenvironment (TME) is critical for tumor prognosis. While pro-angiogenic and immunosuppressive TME promote tumor growth, anti-angiogenic and immune stimulatory TME inhibit tumor progression. Therefore, there is a great interest in achieving vascular normalization to improve drug delivery and enhance antitumor immunity. However, anti-vascular endothelial growth factor (VEGF) mechanisms to normalize tumor vessels have offered limited therapeutic efficacies for patients with cancer. Here, we report that Myct1, a direct target of ETV2, was nearly exclusively expressed in endothelial cells. In preclinical mouse tumor models, Myct1 deficiency reduced angiogenesis, enhanced high endothelial venule formation, and promoted antitumor immunity, leading to restricted tumor progression. Analysis of The Cancer Genome Atlas (TCGA) datasets revealed a significant (P < 0.05) correlation between MYCT1 expression, angiogenesis, and antitumor immunity in human cancers, as suggested by decreased FOXP3 expression and increased antitumor macrophages in patients with low MYCT1 expression. Mechanistically, MYCT1 interacted with tight junction protein Zona Occludens 1 and regulated Rho GTPase-mediated actin cytoskeleton dynamics, thereby promoting endothelial motility in the angiogenic environment. Myct1-deficient endothelial cells facilitated trans-endothelial migration of cytotoxic T lymphocytes and polarization of M1 macrophages. Myct1 targeting combined with anti-PD1 treatment significantly (P < 0.05) increased complete tumor regression and long-term survival in anti-PD1-responsive and -refractory tumor models in mice. Our data collectively support a critical role for Myct1 in controlling tumor angiogenesis and reprogramming tumor immunity. Myct1-targeted vascular control, in combination with immunotherapy, may become an exciting therapeutic strategy.

The Influence of Cell Cycle Regulation on Chemotherapy

Cell cycle regulation is orchestrated by a complex network of interactions between proteins, enzymes, cytokines, and cell cycle signaling pathways, and is vital for cell proliferation, growth, and repair. The occurrence, development, and metastasis of tumors are closely related to the cell cycle. Cell cycle regulation can be synergistic with chemotherapy in two aspects: inhibition or promotion. The sensitivity of tumor cells to chemotherapeutic drugs can be improved with the cooperation of cell cycle regulation strategies. This review presented the mechanism of the commonly used chemotherapeutic drugs and the effect of the cell cycle on tumorigenesis and development, and the interaction between chemotherapy and cell cycle regulation in cancer treatment was briefly introduced. The current collaborative strategies of chemotherapy and cell cycle regulation are discussed in detail. Finally, we outline the challenges and perspectives about the improvement of combination strategies for cancer therapy.

Heterotypic Tumor Spheroids in Agitation-Based Cultures: A Scaffold-Free Cell Model That Sustains Long-Term Survival of Endothelial Cells

Endothelial cells (ECs) are an important component of the tumor microenvironment, playing key roles in tumor development and progression that span from angiogenesis to immune regulation and drug resistance. Heterotypic tumor spheroids are one of the most widely used in vitro tumor microenvironment models, presenting improved recapitulation of tumor microenvironments compared to 2D cultures, in a simple and low-cost setup. Heterotypic tumor spheroid models incorporating endothelial cells have been proposed but present multiple limitations, such as the short culture duration typically obtained, the use of animal-derived matrices, and poor reproducibility; the diversity of culture conditions employed hinders comparison between studies and standardization of relevant culture parameters. Herein, we developed long-term cultures of triple heterotypic spheroids composed of the HCC1954 tumor cell line, human fibroblasts, and ECs. We explored culture parameters potentially relevant for EC maintenance, such as tumor cell line, seeding cell number, cell ratio, and agitation vs. static culture. In HCC1954-based spheroids, we observed maintenance of viable EC for up to 1 month of culture in agitation, with retention of the identity markers CD31 and von Willebrand factor. At the optimized tumor cell:fibroblast:EC ratio of 1:3:10, HCC1954-based spheroids had a higher EC area/total spheroid area at 1 month of culture than the other cell ratios tested. EC maintenance was tumor cell line-dependent, and in HCC1954-based spheroids it was also dependent on the presence of fibroblasts and agitation. Moreover, vascular endothelial growth factor (VEGF) supplementation was not required for maintenance of EC, as the factor was endogenously produced. ECs co-localized with fibroblasts, which accumulated preferentially in the core of the spheroids and secreted EC-relevant extracellular matrix proteins, such as collagen I and IV. This simple model setup does not rely on artificial or animal-derived scaffolds and can serve as a useful tool to explore the culture parameters influencing heterotypic spheroids, contributing to model standardization, as well as to explore molecular cross talk of ECs within the tumor microenvironment, and potentially its effects on drug response.

Disseminated Melanoma Cells Transdifferentiate into Endothelial Cells in Intravascular Niches at Metastatic Sites

Tumor cell plasticity, including transdifferentiation, is thought to be a key driver of therapy failure, tumor dormancy, and metastatic dissemination. Although melanoma cells have been shown to adopt various phenotypic features in vitro, direct in vivo evidence of metastatic cell plasticity remains sparse. Here, we combine lineage tracing in a spontaneous metastatic mouse model of melanoma, advanced imaging, and single-cell RNA sequencing approaches to search for pathophysiologically relevant melanoma cellular states. We identify melanoma cells in intravascular niches of various metastatic organs. These cells are quiescent, are negative for characteristic melanoma markers, and acquire endothelial cell features. We replicate the endothelial transdifferentiation (EndT) finding in another mouse model and provide evidence of EndT in BRAF^V600E-metastatic biopsies from human lung, brain, and small intestine, thus highlighting the clinical relevance of these findings. The tumor-vasculature pattern described herein may contribute to melanoma dormancy within metastatic organs and represent a putative target for therapies.

The heterogeneity of cancer endothelium: The relevance of angiogenesis and endothelial progenitor cells in cancer microenvironment

Tumor-associated vessels constitution is the result of angiogenesis, the hallmark of cancer essential for tumor to develop in dimension and to spread throughout the organism. Tumor endothelium is configured as an active functioning organ capable of determine interaction with the immune response and all the other components of the variegate cancer microenvironment, determining reciprocal influence. Angiogenesis is here analyzed in its molecular and cellular mechanisms, multiple mediators and principal players, represented by Endothelial Cells. It is discussed the striking heterogeneity of cancer endothelium, due to morphological and molecular aberrations that it often presents and its multiple origin. Among the cells that participate to the composition of tumor vasculature, Endothelial Progenitor Cells represent an important source for physical sustain and paracrine signaling in the process of angiogenesis. Treatment options are reviewed, with particular focus on novel therapeutic strategies for overcoming tumor resistance to anti-angiogenic agents.

Correlation between ELF-PEMF exposure and Human RPE Cell Proliferation, Apoptosis and Gene Expression

Purpose

Emerging evidence implies that electromagnetic fields (EMFs) can negatively affect angiogenesis. In this regard, the effects of extremely low frequency pulsed electromagnetic field (ELF-PEMF) exposure on the relative expression level of angiogenic factors involved in the pathogenesis of ocular disorders were evaluated in human retinal pigment epithelial (hRPE) cells in order to investigate a noninvasive therapeutic method for patients with several ocular diseases associated with neovascularization.

Methods

After separating hRPE cells from globes, hRPE cells were exposed to 15 mT of ELF-PEMF (120 Hz) at 5, 10, and 15 min for seven days. Cell proliferation and apoptosis of treated cells were evaluated via ELISA assay. Moreover, relative expression changes of HIF-1α, CTGF, VEGFA, MMP-2, cathepsin D, and E2F3 were performed using real-time RT-PCR.

Results

ELF-PEMF exposure had no significant effects on the apoptosis and proliferation rate of hRPE cells. Expression level of HIF-1α, CTGF, VEGFA, MMP-2, cathepsin D, and E2F3 was downregulated following 5 min of ELF-PEMF exposure.

Conclusion

As ELF-PEMF showed inhibitory effects on the expression of angiogenic genes in hRPE cells with no cytotoxic or proliferative side effects, it can be introduced as a useful procedure for managing angiogenesis induced by retinal pathogenesis, although more studies with adequate follow-up in animal models are needed.

RGD-Binding Integrins Revisited: How Recently Discovered Functions and Novel Synthetic Ligands (Re-)Shape an Ever-Evolving Field

Simple Summary

Integrins, a superfamily of cell adhesion receptors, were extensively investigated as therapeutic targets over the last decades, motivated by their multiple functions, e.g., in cancer (progression, metastasis, angiogenesis), sepsis, fibrosis, and viral infections. Although integrin-targeting clinical trials, especially in cancer, did not meet the high expectations yet, integrins remain highly interesting therapeutic targets. In this article, we analyze the state-of-the-art knowledge on the roles of a subfamily of integrins, which require binding of the tripeptide motif Arg-Gly-Asp (RGD) for cell adhesion and signal transduction, in cancer, in tumor-associated exosomes, in fibrosis and SARS-CoV-2 infection. Furthermore, we outline the latest achievements in the design and development of synthetic ligands, which are highly selective and affine to single integrin subtypes, i.e., αvβ3, αvβ5, α5β1, αvβ6, αvβ8, and αvβ1. Lastly, we present the substantial progress in the field of nuclear and optical molecular imaging of integrins, including first-in-human and clinical studies.

Abstract

Integrins have been extensively investigated as therapeutic targets over the last decades, which has been inspired by their multiple functions in cancer progression, metastasis, and angiogenesis as well as a continuously expanding number of other diseases, e.g., sepsis, fibrosis, and viral infections, possibly also Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). Although integrin-targeted (cancer) therapy trials did not meet the high expectations yet, integrins are still valid and promising targets due to their elevated expression and surface accessibility on diseased cells. Thus, for the future successful clinical translation of integrin-targeted compounds, revisited and innovative treatment strategies have to be explored based on accumulated knowledge of integrin biology. For this, refined approaches are demanded aiming at alternative and improved preclinical models, optimized selectivity and pharmacological properties of integrin ligands, as well as more sophisticated treatment protocols considering dose fine-tuning of compounds. Moreover, integrin ligands exert high accuracy in disease monitoring as diagnostic molecular imaging tools, enabling patient selection for individualized integrin-targeted therapy. The present review comprehensively analyzes the state-of-the-art knowledge on the roles of RGD-binding integrin subtypes in cancer and non-cancerous diseases and outlines the latest achievements in the design and development of synthetic ligands and their application in biomedical, translational, and molecular imaging approaches. Indeed, substantial progress has already been made, including advanced ligand designs, numerous elaborated pre-clinical and first-in-human studies, while the discovery of novel applications for integrin ligands remains to be explored.

Metastasis-Initiating Cells and Ecosystems

Metastasis is initiated and sustained through therapy by cancer cells with stem-like and immune-evasive properties, termed metastasis-initiating cells (MIC). Recent progress suggests that MICs result from the adoption of a normal regenerative progenitor phenotype by malignant cells, a phenotype with intrinsic programs to survive the stresses of the metastatic process, undergo epithelial-mesenchymal transitions, enter slow-cycling states for dormancy, evade immune surveillance, establish supportive interactions with organ-specific niches, and co-opt systemic factors for growth and recurrence after therapy. Mechanistic understanding of the molecular mediators of MIC phenotypes and host tissue ecosystems could yield cancer therapeutics to improve patient outcomes. SIGNIFICANCE: Understanding the origins, traits, and vulnerabilities of progenitor cancer cells with the capacity to initiate metastasis in distant organs, and the host microenvironments that support the ability of these cells to evade immune surveillance and regenerate the tumor, is critical for developing strategies to improve the prevention and treatment of advanced cancer. Leveraging recent progress in our understanding of the metastatic process, here we review the nature of MICs and their ecosystems and offer a perspective on how this knowledge is informing innovative treatments of metastatic cancers.

Role of bFGF in Acquired Resistance upon Anti-VEGF Therapy in Cancer

Anti-angiogenic approaches targeting the vascular endothelial growth factor (VEGF) signaling pathway have been a significant research focus during the past decades and are well established in clinical practice. Despite the expectations, their benefit is ephemeral in several diseases, including specific cancers. One of the most prominent side effects of the current, VEGF-based, anti-angiogenic treatments remains the development of resistance, mostly due to the upregulation and compensatory mechanisms of other growth factors, with the basic fibroblast growth factor (bFGF) being at the top of the list. Over the past decade, several anti-angiogenic approaches targeting simultaneously different growth factors and their signaling pathways have been developed and some have reached the clinical practice. In the present review, we summarize the knowledge regarding resistance mechanisms upon anti-angiogenic treatment, mainly focusing on bFGF. We discuss its role in acquired resistance upon prolonged anti-angiogenic treatment in different tumor settings, outline the reported resistance mechanisms leading to bFGF upregulation, and summarize the efforts and outcome of combined anti-angiogenic approaches to date.

Proanthocyanidins as a Potential Novel Way for the Treatment of Hemangioma

Hemangioma, the most common benign vascular tumor, not only affects the appearance and psychology but also has a life-threatening potential. It is considered that clonal vascular endothelial cell proliferation and excessive angiogenesis are responsible for hemangioma pathogenesis, in which abnormal cytokines/pathways are closely implicated, primarily including high expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) as well as their downstream pathways, especially phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt). These further stimulate the migration and proliferation of vascular endothelial cells and promote the formation of new vessels, ultimately leading to the occurrence and development of hemangioma. Proanthocyanidins are naturally active substance from plants and fruits. They possess multiple functions like antiproliferation, antiangiogenesis, and antitumor. It has been demonstrated that proanthocyanidins effectively work in various diseases via inhibiting the expression of various factors, e.g., HIF-1α, VEGF, PI3K, and Akt. Considering the pathogenesis of hemangioma and the effect of proanthocyanidins, we hold a hypothesis that proanthocyanidins would be applied in hemangioma via downregulating cytokine/pathway expression, suppressing vascular cell proliferation and arrest abnormal angiogenesis. Taken together, proanthocyanidins may be a potential novel way for the treatment of hemangioma.

Anti-angiogenic Agents in Combination With Immune Checkpoint Inhibitors: A Promising Strategy for Cancer Treatment

Advances in cancer immunity have promoted a major breakthrough in the field of cancer therapy. This is mainly associated with the successful development of immune checkpoint inhibitors (ICIs) for multiple types of human tumors. Blockade with different ICIs, including programmed cell death 1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, may activate the immune system of the host against malignant cells. However, only a subgroup of patients with cancer would benefit from immune checkpoint blockade. Some patients experience primary resistance to initial immunotherapy, and a majority eventually develop acquired resistance to ICIs. However, the mechanisms involved in the development of drug resistance to immune checkpoint blockade remain unclear. Recent studies supported that combination of ICIs and anti-angiogenic agents could be a promising therapeutic strategy for overcoming the low efficacy of ICIs. Moreover, through their direct anti-cancer effect by inhibiting tumor growth and metastasis, anti-angiogenic drugs reprogram the tumor milieu from an immunosuppressive to an immune permissive microenvironment. Activated immunity by immune checkpoint blockade also facilitates anti-angiogenesis by downregulating the expression of vascular endothelial growth factor and alleviating hypoxia condition. Many clinical trials showed an improved anti-cancer efficacy and prolonged survival following the addition of anti-angiogenic agents to ICIs. This review summarizes the current understanding and clinical development of combination therapy with immune checkpoint blockade and anti-angiogenic strategy.

Biological Properties, Bioactive Constituents, and Pharmacokinetics of Some Capsicum spp. and Capsaicinoids

Pepper originated from the Capsicum genus, which is recognized as one of the most predominant and globally distributed genera of the Solanaceae family. It is a diverse genus, consisting of more than 31 different species including five domesticated species, Capsicum baccatum, C. annuum, C. pubescen, C. frutescens, and C. chinense. Pepper is the most widely used spice in the world and is highly valued due to its pungency and unique flavor. Pepper is a good source of provitamin A; vitamins E and C; carotenoids; and phenolic compounds such as capsaicinoids, luteolin, and quercetin. All of these compounds are associated with their antioxidant as well as other biological activities. Interestingly, Capsicum fruits have been used as food additives in the treatment of toothache, parasitic infections, coughs, wound healing, sore throat, and rheumatism. Moreover, it possesses antimicrobial, antiseptic, anticancer, counterirritant, appetite stimulator, antioxidant, and immunomodulator activities. Capsaicin and Capsicum creams are accessible in numerous ways and have been utilized in HIV-linked neuropathy and intractable pain.

Anti-metastatic effect of midazolam on melanoma B16F10 cells in the lungs of diabetic mice

Midazolam is an anesthetic agent commonly used for anesthesia and sedation in surgery. However, there is no information on the role of midazolam in hyperglycemia-induced cancer metastasis to date. In this study, we investigated the effects of midazolam on inhibiting metastases in the lungs of diabetic mice and on human pulmonary microvascular endothelial cells (HPMVECs). Subcutaneous injection of midazolam inhibited hyperglycemia-induced cancer metastasis in the lungs of diabetic mice. Midazolam also prevented the generation of ROS, activation of TGase, and subsequent vascular leakage in the lungs of diabetic mice. Furthermore, in vitro studies with HPMVECs confirmed that midazolam inhibited VEGF-induced intracellular events including ROS generation, TGase activation, and disruption of vascular endothelial-cadherins, thus preventing the permeability of endothelial cells. Notably, midazolam had no direct effect on the migration or proliferation of melanoma cells, instead acting upon endothelial cells. The midazolam-mediated inhibition of VEGF-induced intracellular events was reversed by treatment with the GABA_A receptor antagonist flumazenil. These findings suggest that midazolam prevents hyperglycemia-induced cancer metastasis by inhibiting VEGF-induced intracellular events and subsequent vascular leakage via the GABA_A receptors in the lungs of diabetic mice.

Angiogenesis in Breast Cancer Progression, Diagnosis, and Treatment

Angiogenesis is a significant event in a wide range of healthy and diseased conditions. This process frequently involves vasodilation and an increase in vascular permeability. Numerous players referred to as angiogenic factors, work in tandem to facilitate the outgrowth of endothelial cells (EC) and the consequent vascularity. Conversely, angiogenic factors could also feature in pathological conditions. Angiogenesis is a critical factor in the development of tumors and metastases in numerous cancers. An increased level of angiogenesis is associated with decreased survival in breast cancer patients. Therefore, a good understanding of the angiogenic mechanism holds a promise of providing effective treatments for breast cancer progression, thereby enhancing patients' survival. Disrupting the initiation and progression of this process by targeting angiogenic factors such as vascular endothelial growth factor (Vegf)-one of the most potent member of the VEGF family- or by targeting transcription factors, such as Hypoxia-Inducible Factors (HIFs) that act as angiogenic regulators, have been considered potential treatment options for several types of cancers. The objective of this review is to highlight the mechanism of angiogenesis in diseases, specifically its role in the progression of malignancy in breast cancer, as well as to highlight the undergoing research in the development of angiogenesis-targeting therapies.

Anti-VEGF Treatment Enhances CD8+ T-cell Antitumor Activity by Amplifying Hypoxia

Antiangiogenic therapies that target the VEGF pathway have been used clinically to combat cancer for over a decade. Beyond having a direct impact on blood vessel development and tumor perfusion, accumulating evidence indicates that these agents also affect antitumor immune responses. Numerous clinical trials combining antiangiogenic drugs with immunotherapies for the treatment of cancer are ongoing, but a mechanistic understanding of how disruption of tumor angiogenesis may impact immunity is not fully discerned. Here, we reveal that blockade of VEGF-A with a mAb to VEGF augments activation of CD8⁺ T cells within tumors and potentiates their capacity to produce cytokines. We demonstrate that this phenomenon relies on the disruption of VEGFR2 signaling in the tumor microenvironment but does not affect CD8⁺ T cells directly. Instead, the augmented functional capacity of CD8⁺ T cells stems from increased tumor hypoxia that initiates a hypoxia-inducible factor-1α program within CD8⁺ T cells that directly enhances cytokine production. Finally, combinatorial administration of anti-VEGF with an immunotherapeutic antibody, anti-OX40, improved antitumor activity over single-agent treatments. Our findings illustrate that anti-VEGF treatment enhances CD8⁺ T-cell effector function and provides a mechanistic rationale for combining antiangiogenic and immunotherapeutic drugs for cancer treatment.

Bevacizumab (Avastin®) in cancer treatment: A review of 15 years of clinical experience and future outlook

When the VEGF-A-targeting monoclonal antibody bevacizumab (Avastin®) entered clinical practice more than 15 years ago, it was one of the first targeted therapies and the first approved angiogenesis inhibitor. Marking the beginning for a new line of anti-cancer treatments, bevacizumab remains the most extensively characterized anti-angiogenetic treatment. Initially approved for treatment of metastatic colorectal cancer in combination with chemotherapy, its indications now include metastatic breast cancer, non-small-cell lung cancer, glioblastoma, renal cell carcinoma, ovarian cancer and cervical cancer. This review provides an overview of the clinical experience and lessons learned since bevacizumab's initial approval, and highlights how this knowledge has led to the investigation of novel combination therapies. In the past 15 years, our understanding of VEGF's role in the tumor microenvironment has evolved. We now know that VEGF not only plays a major role in controlling blood vessel formation, but also modulates tumor-induced immunosuppression. These immunomodulatory properties of bevacizumab have opened up new perspectives for combination therapy approaches, which are being investigated in clinical trials. Specifically, the combination of bevacizumab with cancer immunotherapy has recently been approved in non-small-cell lung cancer and clinical benefit was also demonstrated for treatment of hepatocellular carcinoma. However, despite intense investigation, reliable and validated biomarkers that would enable a more personalized use of bevacizumab remain elusive. Overall, bevacizumab is expected to remain a key agent in cancer therapy, both due to its established efficacy in approved indications and its promise as a partner in novel targeted combination treatments.

The Warburg metabolism fuels tumor metastasis

The Warburg effect is prevalent in human cancer. Accordingly, most cancer cells display highly elevated glycolysis without proportionally increasing pyruvate oxidation. The metastatic process imposes strong selective pressure on cancer cells, and metastasizing cancer cells experience heightened oxidative stress. By constraining mitochondrial oxidative metabolism, the Warburg effect helps cancer cells to minimize oxidative stress, thereby facilitating metastatic dissemination. The PGC1α transcriptional coactivator is a central coordinator of oxidative metabolism. While promoting oxidative metabolism and reversing the Warburg effect, PGC1α critically activates antioxidant genes and protects cells against oxidative damage. Therefore, depending on the context, PGC1α may promote or suppress tumor metastasis. Cancer cells generally retain metabolic flexibility and can resist antiglycolysis treatment by undergoing metabolic reprogramming. Synthetic lethal combination therapies are thus essential to attack the liabilities of the Warburg metabolism for therapeutic benefit.

Role of alternative splicing of VEGF-A in the development of atherosclerosis

Vascular endothelial cell growth factor A (VEGF-A) signaling promotes the endothelial cell proliferation, macrophage infiltration and foam cell formation, which play pivotal roles in the pathogenesis of atherosclerosis (AS). However, the role of alternative splicing of VEGF here is not known. Here, ApoE (-/-) mice supplied high-fat diet (HFD mice) were used to generate AS, while ApoE (-/-) mice supplied with normal diet (NOR mice) were used as a control. Aortic endothelial cells (AECs) and infiltrated macrophages were purified and quantified by flow cytometry. Alternative splicing of VEGF and the regulator of VEGF splicing, SRPK1, were assessed by RT-qPCR and immunoblotting in both AECs and aortic macrophages. We found that HFD mice developed AS in 12 weeks, while the NOR did not. Compared to NOR mice, HFD mice possessed significantly more AECs and AEC proliferation, and had significantly more aortic infiltrated macrophages and more apoptosis of them. Significant shift of VEGF-A splicing to pro-angiogenic VEGF₁₆₅ was detected in both AECs and macrophages from HFD mice, seemingly through upregulation of SRPK1. In vitro, SRPK1 overexpression significantly increased EC proliferation and macrophage apoptosis. Thus, our data suggest that alternative splicing of VEGF-A to pro-angiogenic VEGF₁₆₅ may contribute to the development of AS.

Atezolizumab in combination with bevacizumab, paclitaxel and carboplatin for the first-line treatment of patients with metastatic non-squamous non-small cell lung cancer, including patients with EGFR mutations

Introduction: Cancer immunotherapy has revolutionized the treatment of patients with advanced or metastatic non-small cell lung cancer (NSCLC). However, specific patient groups (e.g. patients with activating epidermal growth factor receptor [EGFR] mutations) do not appear to derive benefit from immune checkpoint inhibitor (ICI) monotherapy. Combining ICIs, such as atezolizumab, with chemotherapy and/or targeted therapies may help to address this unmet need.Areas covered: Atezolizumab is an anti-programmed death-ligand 1 therapy for several tumor types. We review its clinical efficacy and safety in the treatment of advanced or metastatic NSCLC, with a specific focus on the combination of atezolizumab with bevacizumab, carboplatin, and paclitaxel (ABCP). Data from IMpower150 show that the ABCP regimen provided clinical benefit to patients with non-squamous NSCLC, including those with EGFR mutations.Expert opinion: Combining ICIs with chemotherapy has proven to be superior to chemotherapy alone. However, tumor resistance to ICIs will likely increase as these drugs enter earlier lines of therapy, underscoring a need for effective treatments when immunotherapy fails. Data suggest that the ABCP regimen may circumvent ICI resistance mechanisms. Continued investigation into the regimen's mechanisms, improved patient profiling/selection, and treatment personalization will drive further development/discoveries.

Rewiring of Lipid Metabolism and Storage in Ovarian Cancer Cells after Anti-VEGF Therapy

Anti-angiogenic therapy triggers metabolic alterations in experimental and human tumors, the best characterized being exacerbated glycolysis and lactate production. By using both Liquid Chromatography-Mass Spectrometry (LC-MS) and Nuclear Magnetic Resonance (NMR) analysis, we found that treatment of ovarian cancer xenografts with the anti-Vascular Endothelial Growth Factor (VEGF) neutralizing antibody bevacizumab caused marked alterations of the tumor lipidomic profile, including increased levels of triacylglycerols and reduced saturation of lipid chains. Moreover, transcriptome analysis uncovered up-regulation of pathways involved in lipid metabolism. These alterations were accompanied by increased accumulation of lipid droplets in tumors. This phenomenon was reproduced under hypoxic conditions in vitro, where it mainly depended from uptake of exogenous lipids and was counteracted by treatment with the Liver X Receptor (LXR)-agonist GW3965, which inhibited cancer cell viability selectively under reduced serum conditions. This multi-level analysis indicates alterations of lipid metabolism following anti-VEGF therapy in ovarian cancer xenografts and suggests that LXR-agonists might empower anti-tumor effects of bevacizumab.

A Tumor-in-Host DEB-Based Approach for Modeling Cachexia and Bevacizumab Resistance

Adequate energy intake and homeostasis are fundamental for the appropriate growth and maintenance of an organism; the presence of a tumor can break this equilibrium. Tumor energy requests can lead to extreme weight loss in animals and cachexia in cancer patients. Angiogenesis inhibitors, acting on tumor vascularization, counteract this tumor-host energy imbalance, with significant results in preclinical models and more limited results in the clinic. Current pharmacokinetic-pharmacodynamic models mainly focus on the antiangiogenic effects on tumor growth but do not provide information about host conditions. A model that can predict energetic conditions that provide significant tumor growth inhibition with acceptable host body weight reduction is therefore needed. We developed a new tumor-in-host dynamic energy budget (DEB)-based model to account for the cytostatic activity of antiangiogenic treatments. Drug effect was implemented as an inhibition of the energy fraction subtracted from the host by the tumor. The model was tested on seven xenograft experiments involving bevacizumab and three different tumor cell lines. The model successfully predicted tumor and host body growth data, providing a quantitative measurement of drug potency and tumor-related cachexia. The inclusion of a hypoxia-triggered resistance mechanism enabled investigation of the decreased efficacy frequently observed with prolonged bevacizumab treatments. In conclusion, the tumor-in-host DEB-based approach has been extended to account for the effect of bevacizumab. The resistance model predicts the response to different administration protocols and, for the first time, the impact of tumor-related cachexia in different cell lines. Finally, the physiologic base of the model strongly suggests its use in translational human research. SIGNIFICANCE: A mathematical model describes tumor growth in animal models, taking into consideration the energy balance involving both the growth of tumor and the physiologic functions of the host.

Heparin potentiates Avastin-mediated inhibition of VEGF binding to fibronectin and rescues Avastin activity at acidic pH

Vascular endothelial growth factor-A (VEGF) plays a critical role in stimulating angiogenesis in normal and disease states. Anti-VEGF antibodies have been developed to manage pathological angiogenesis. Bevacizumab, sold under the brand name Avastin, is a humanized mAb that binds VEGF and blocks its binding to its signaling receptor, VEGF receptor 2, and is used to treat patients with a variety of cancers or retinal disorders. The ability of Avastin to modulate other nonreceptor interactions of VEGF has not been fully defined. In this study, we investigated Avastin's capacity to modulate VEGF165 binding to porcine aortic endothelial cells and to heparin and fibronectin (FN) across a range of pH values (pH 5-8). We observed that Avastin slightly enhanced VEGF binding to heparin and that heparin increased VEGF binding to Avastin. In contrast, Avastin inhibited VEGF binding to cells and FN, yet Avastin could still bind to VEGF that was bound to FN, indicating that these binding events are not mutually exclusive. Avastin binding to VEGF was dramatically reduced at acidic pH values (pH 5.0-6.5), whereas VEGF binding to FN and nonreceptor sites on cells was enhanced. Interestingly, the reduced Avastin-VEGF binding at acidic pH was rescued by heparin, as was Avastin's ability to inhibit VEGF binding to cells. These results suggest that heparin might be used to expand the clinical utility of Avastin. Our findings highlight the importance of defining the range of VEGF interactions to fully predict antibody activity within a complex biological setting.

Transarterial Chemoembolisation (TACE) with Degradable Starch Microspheres (DSM) and Anthracycline in Patients with Locally Extensive Hepatocellular Carcinoma (HCC): Safety and Efficacy

PURPOSE

To evalutate safety and efficacy of degradable starch microspheres (DSM) as embolic agent in transarterial chemoembolisation (TACE) of unresectable, locally extensive hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In this retrospective study, 37 patients with intermediate to advanced HCC treated with ≥ 3 chemoembolisations with doxorubicin/epirubicin and DSM were analysed. Patients were treated with three consecutive chemoembolisations in 4-weekly intervals. Clinical parameters and laboratory findings were obtained from patient records before and after each intervention. Tumour response was assessed after every 3 embolisations by CT/MRI according to modified response evaluation criteria in solid tumours.

RESULTS

Thirty-seven patients with HCC were treated with 177 DSM-TACEs (3-12/patient, mean 4.8). Disease stages according to the Barcelona Clinic Liver Cancer (BCLC) staging system were: 27 × B, 9 × C, 1 × D. Five patients had uninodular, 32 multinodular (23 bilobar) disease. Three patients had portal vein invasion. Apart from one possibly procedure-related grade 3 complication, only grade 1 adverse events occurred. These were pain reacting to analgesics (23%), transient nausea (11%), vomiting (3%) and post-embolisation syndrome (4%). Transient laboratory changes were bone marrow toxicity (29%) and increase in INR (14%), creatinine (8%) or bilirubin (38%). Tumour response was objective response rate 49%, disease control rate 83%. Median survival was 19 months: 22 months for BCLC stage B and 6.7 months for BCLC stages C + D. Responders had a significantly better prognosis than non-responders.

CONCLUSION

DSM-TACE of HCC is safe even in patients with advanced disease stages. Tumour response and survival rates were encouraging in our series of patients with locally extensive disease.

Preclinical rationale and clinical efficacy of antiangiogenic therapy and immune checkpoint blockade combination therapy in urogenital tumors

PURPOSE

In recent years, immune checkpoint blockade (ICB) therapies have shown good clinical responses in various solid cancers. However, a major challenge in the process of ICB treatment is when tumors do not have enough infiltrating T cells. Antiangiogenic drugs targeting vascular endothelial growth factor (VEGF) and its receptors have been approved for the treatment of various malignant solid tumors alone or in combination with other therapies. Our review mainly discusses the preclinical rationale and clinical efficacy of antiangiogenic and ICB combination therapy in urogenital tumors.

METHODS

We reviewed relevant literature on preclinical research and clinical trial results regarding antiangiogenic and ICB combination therapy in urogenital tumors from PubMed. In addition, we searched ongoing clinical trials on ClinicalTrials.gov to collect information related to this specific topic.

RESULTS

Antiangiogenesis therapy could enhance T cell recruitment and increase T cell infiltration into the tumor microenvironment by blocking VEGF-VEGF receptor 2 binding and downstream signaling pathways to normalize tumor blood vessels. The combination of ICB and antiangiogenesis therapy could improve antitumor activity according to subsequent preclinical experiments and several phase I/II/III clinical trials on urogenital tumors.

CONCLUSION

Combined therapy has shown some antitumor efficacy in several urogenital tumors, such as metastatic renal cell carcinoma, metastatic urothelial and genitourinary tumors, endometrial carcinoma, ovarian cancer, and fallopian tube cancer. Combination therapy is a promising strategy that can be used to improve the therapeutic efficacy, and the identification of precise biomarkers of this combined therapy is the direction of future studies.

Real-World Clinical and Economic Outcomes and the Role of Bevacizumab in Patients With Non-Small-Cell Lung Cancer With Liver Metastases

PURPOSE

Liver metastases are associated with poor outcomes in patients with advanced non-small-cell lung cancer (aNSCLC). Nevertheless, the vasculature in the liver microenvironment may be conducive to the use of antiangiogenesis inhibitors to potentially improve outcomes. Limited real-world clinical and economic data are currently available for this patient subpopulation.

METHODS

Two retrospective cohort analyses were conducted using data from an electronic health record (n = 14,209) and a claims database (n = 9,017). Patients with aNSCLC with and without liver metastases were identified in each database. Patients with baseline liver metastases in the electronic health record database were further categorized into two subgroups-those who had or had not received bevacizumab-containing regimens. Multivariable Cox proportional hazards regression models were used to adjust for baseline characteristics to evaluate the effect of treatment of bevacizumab.

RESULTS

Liver metastases were associated with significantly poorer survival (median overall survival, 6.3 months v 10.1 months) and higher costs and health care resource utilization-total per-patient-per-month costs of $27,589 versus $19,607. Cost differences were primarily driven by inpatient costs, including a two-fold increase in hospitalizations and a 1.7-fold higher mean length of stay. Treatment with bevacizumab was associated with improved survival. Whereas overall survival improved in patients with and without baseline liver metastases who received bevacizumab, the relative survival benefit was greater in patients with liver metastases (hazard ratio, 0.63 [95% CI, 0.50 to 0.81] v hazard ratio, 0.80 [95% CI, 0.74 to 0.86]).

CONCLUSION

Patients with aNSCLC with liver metastases have poorer survival and a higher cost and health care resource utilization burden. Bevacizumab was associated with a survival benefit in patients with aNSCLC with liver metastases.

MICAL2 is expressed in cancer associated neo-angiogenic capillary endothelia and it is required for endothelial cell viability, motility and VEGF response

The capacity of inducing angiogenesis is a recognized hallmark of cancer cells. The cancer microenvironment, characterized by hypoxia and inflammatory signals, promotes proliferation, migration and activation of quiescent endothelial cells (EC) from surrounding vascular network. Current anti-angiogenic drugs present side effects, temporary efficacy, and issues of primary resistance, thereby calling for the identification of new therapeutic targets. MICALs are a unique family of redox enzymes that destabilize F-actin in cytoskeletal dynamics. MICAL2 mediates Semaphorin3A-NRP2 response to VEGFR1 in rat ECs. MICAL2 also enters the p130Cas interactome in response to VEGF in HUVEC. Previously, we showed that MICAL2 is overexpressed in metastatic cancer. A small-molecule inhibitor of MICAL2 exists (CCG-1423). Here we report that 1) MICAL2 is expressed in neo-angiogenic ECs in human solid tumors (kidney and breast carcinoma, glioblastoma and cardiac myxoma, n = 67, were analyzed with immunohistochemistry) and in animal models of ischemia/inflammation neo-angiogenesis, but not in normal capillary bed; 2) MICAL2 protein pharmacological inhibition (CCG-1423) or gene KD reduce EC viability and functional performance; 3) MICAL2 KD disables ECs response to VEGF in vitro. Whole-genome gene expression profiling reveals MICAL2 involvement in angiogenesis and vascular development pathways. Based on these results, we propose that MICAL2 expression in ECs participates to inflammation-induced neo-angiogenesis and that MICAL2 inhibition should be tested in cancer- and noncancer-associated neo-angiogenesis, where chronic inflammation represents a relevant pathophysiological mechanism.

Capsaicinoids: Multiple effects on angiogenesis, invasion and metastasis in human cancers

Cancer progression is a complex multistep process comprising of angiogenesis of the primary tumor, its invasion into the surrounding stroma and its migration to distant organs to produce metastases. Nutritional compounds of the "capsaicinoid" family regulate angiogenesis, invasion and metastasis of tumors. Capsaicinoids display robust anti-angiogenic activity in both cell culture and mice models. However, conflicting reports exist about the effect of capsaicinoids on invasion of metastasis of cancers. While some published reports have described an anti-invasive and anti-metastatic role for capsaicinoids, others have argued that capsaicinoids stimulate invasion and metastasis of cancers. The present review article summarizes these findings involving the bioactivity of capsaicin in angiogenesis, invasion and metastasis of cancer. A survey of literature indicate that they are several articles summarizing the growth-inhibitory activity of capsaicinoids but few describe its effects on angiogenesis, invasion and metastasis in detail. Our review article fills this gap of knowledge. The discovery of a second generation of natural and synthetic capsaicin analogs (with anti-tumor activity) will pave the way to improved strategies for the treatment of several human cancers.

[68Ga]RGD Versus [18F]FDG PET Imaging in Monitoring Treatment Response of a Mouse Model of Human Glioblastoma Tumor with Bevacizumab and/or Temozolomide

PURPOSE

The aim of this study was to evaluate positron emission tomography (PET) imaging with [⁶⁸Ga]NODAGA-c(RGDfK) ([⁶⁸Ga]RGD), in comparison with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG), for early monitoring of the efficacy of an antiangiogenic agent associated or not with chemotherapy, in a mouse model of glioblastoma (GB).

PROCEDURES

Mice bearing U87MG human GB cells line were parted into five groups of five mice each. One group was imaged at baseline before the treatment phase; another group was treated with bevacizumab (BVZ), another group with temozolomide (TMZ), another group with both agents, and the last one was the control group. Tumors growth and biological properties were evaluated by caliper measurements and PET imaging at three time points (baseline, during treatment t1 = 4-6 days and t2 = 10-12 days). At the end of the study, tumors were counted and analyzed by immunohistochemistry (CD31 to evaluate microvessel density).

RESULTS

The tumor volume assessed by caliper measurements was significantly greater at t1 in the control group than in the TMZ + BVZ-treated group or in the BVZ-treated group. At t2, tumor volume of all treated groups was significantly smaller than that of the control group. [¹⁸F]FDG PET failed to reflect this efficacy of treatment. In contrast, at t1, the [⁶⁸Ga]RGD tumor uptake was concordant with tumor growth in controls and in treated groups. At t2, a significant increase in tumor uptake of [⁶⁸Ga]RGD vs. t1 was only observed in the TMZ-treated group, reflecting a lack of angiogenesis inhibition, whereas TMZ + BVZ resulted in a dramatic tumor arrest, reduction in microvessel density and stable tumor [⁶⁸Ga]RGD uptake.

CONCLUSIONS

[⁶⁸Ga]RGD is a useful PET agent for in vivo angiogenesis imaging and can be useful for monitoring antiangiogenic treatment associated or not with chemotherapy.

Human Ocular Angiogenesis-Inspired Vascular Models on an Injection-Molded Microfluidic Chip

Angiogenic sprouting, which is the growth of new blood vessels from pre-existing vessels, is orchestrated by cues from the cellular microenvironment, such as spatially controlled gradients of angiogenic factors. However, current in vitro models are less scalable for in-depth studies of angiogenesis. In this study, a plastic-based microfluidic chip is developed to reconstruct in vitro 3D vascular networks. The main disadvantages of the preexisting system are identified, namely, the low productivity and difficulty of experiments, and a breakthrough is suggested while minimizing disadvantages. The selection of plastic materials contributes to the productivity and usability of in vitro devices. By adopting this material, this chip offers simple fluid patterning, facilitating the construction of a cell-culture microenvironment. Compared with previous systems, the chip, which can form both inward and outwardly radial vascular sprouting, demonstrates the growth of functional, morphologically integral microvessels. The developed angiogenic model yields dose-dependent results for antiangiogenic drug screening. This model may contribute significantly not only to vascular studies under normal and pathological conditions, but also to fundamental research on the ocular neovascularization. Furthermore, it can be applied as a tool for more practical, extended preclinical research, providing an alternative to animal experiments.

Combinations of Bevacizumab With Cancer Immunotherapy

Cancer immunotherapy (CIT) has transformed cancer treatment. In particular, immunotherapies targeting the programmed death ligand 1 (PD-L1)/programmed death 1 pathway have demonstrated durable clinical benefit in some patients. However, CIT combinations may create a more favorable environment in which to maximize the potential of the immune system to eliminate cancer. Here we describe 3 key mechanisms related to vascular endothelial growth factor (VEGF)-mediated immunosuppression: inhibition of dendritic cell maturation, reduction of T-cell tumor infiltration, and promotion of inhibitory cells in the tumor microenvironment; supporting data are also described. In addition, we discuss immunomodulatory properties observed within tumors following bevacizumab treatment. Combining anti-PD-L1 and anti-VEGF therapies has shown synergy and positive outcomes in phases I to III studies, particularly in settings where high VEGF levels are known to play an important role in tumor growth. We also review data from key studies supporting combination of bevacizumab and CIT, with a focus on PD-L1/programmed death 1 inhibitors.

The unconventional role of Akt1 in the advanced cancers and in diabetes-promoted carcinogenesis

Decades of research have elucidated the critical role of Akt isoforms in cancer as pro-tumorigenic and metastatic regulators through their specific effects on the cancer cells, tumor endothelial cells and the stromal cells. The pro-cancerous role of Akt isoforms through enhanced cell proliferation and suppression of apoptosis in cancer cells and the cells in the tumor microenvironment is considered a dogma. Intriguingly, studies also indicate that the Akt pathway is essential to protect the endothelial-barrier and prevent aberrant vascular permeability, which is also integral to tumor perfusion and metastasis. To complicate this further, a flurry of recent reports strongly indicates the metastasis suppressive role of Akt, Akt1 in particular in various cancer types. These reports emanated from different laboratories have elegantly demonstrated the paradoxical effect of Akt1 on cancer cell epithelial-to-mesenchymal transition, invasion, tumor endothelial-barrier disruption, and cancer metastasis. Here, we emphasize on the specific role of Akt1 in mediating tumor cell-vasculature reciprocity during the advanced stages of cancers and discuss how Akt1 differentially regulates cancer metastasis through mechanisms distinct from its pro-tumorigenic effects. Since Akt is integral for insulin signaling, endothelial function, and metabolic regulation, we also attempt to shed some light on the specific effects of diabetes in modulating Akt pathway in the promotion of tumor growth and metastasis.

Harmine suppresses bladder tumor growth by suppressing vascular endothelial growth factor receptor 2-mediated angiogenesis

Angiogenesis is a vital step during the process of oncogenesis of a lot of tumors, with no exception in bladder cancer. One of the useful strategies for the development of new drugs against cancer is targeting angiogenesis. In the present study, we found that a small-molecule natural product, which belonged to the β-carboline alkaloid, named harmine, could strongly inhibit tumor angiogenesis thus exhibiting its ideal treatment efficacy in bladder cancer. In vivo study verified that harmine had the effect of inhibition on human bladder tumor xenograft growth. The inhibitory effect of harmine to bladder cancer growth was coordinated by the effects shown on angiogenesis. To further explore the pharmacological activities of harmine, we tested harmine’s influence on blood vessel formation and found that harmine effectively blocked the microvessel sprouting in rat aortic ring assay when stimulated by vascular endothelial growth factor (VEGF). Furthermore, harmine inhibited human umbilical vein endothelial cell (HUVEC) proliferation as well as chemotactic motility, and when we treated HUVEC cell with harmine, the formation of capillary-like structures was also restrained. Moreover, harmine induced bladder cancer cell apoptosis through triggering the caspase-dependent apoptotic pathway and the downstream vascular endothelial growth factor receptor 2 (VEGFR2) kinase pathway was down-regulated, thus suppressing tumor development signals. Herein, our study demonstrated that natural product harmine might have potential in curing human bladder tumor because of its pharmacological function on tumor angiogenesis, trigged by VEGFR2 signaling pathways.

Gambogic acid impairs tumor angiogenesis by targeting YAP/STAT3 signaling axis

Angiogenesis is central to a wide range of physiological and pathological processes including wound healing, macular degeneration, and cancer. Excessive or inappropriate vascular supply of tumors is one of the main targets for cancer therapy. Recently, critical and selective transcriptional factors such as yes-associated protein (YAP) that control the expression of angiogenesis factors have gained increasing attention in antiangiogenic therapy. In this study, we have identified and characterized a novel inhibitor of YAP, gambogic acid (GA), which exerted striking antiangiogenic effects both in vitro and in vivo. We demonstrated that GA remarkably inhibited a variety of vascular endothelial growth factor-induced angiogenesis processes including proliferation, migration, sprouting, and tube formation of endothelial cells in vitro. In addition, GA resulted in decreased neo-vessel formation in Matrigel plugs of mice and chick chorioallantoic membrane. More importantly, we showed that GA limited tumor growth via preventing tumor angiogenesis and vascular maturation. Further mechanistic studies illustrated that GA directly targeted YAP/STAT3 signaling axis, which is critical for the transcriptional regulation of a series of angiogenic factors. Taken together, these preclinical findings suggest that GA significantly repressed tumor angiogenesis and may serve as a promising drug candidate against cancer.

Rethinking Alkylating(-Like) Agents for Solid Tumor Management

Although old molecules, alkylating agents and platinum derivatives are still widely used in the treatment of various solid tumors. However, systemic toxicity and cellular resistance mechanisms impede their efficacy. Innovative strategies, including local administration, optimization of treatment schedule/dosage, synergistic combinations, and the encapsulation of bioactive molecules in smart, multifunctional drug delivery systems, have shown promising results in potentiating anticancer activity while circumventing such hurdles. Furthermore, questioning of the old paradigm according to which nuclear DNA is the critical target of their anticancer activity has shed light on subcellular alternative and neglected targets that obviously participate in the mediation of cytotoxicity or resistance. Thus, rethinking of the use of these pivotal antineoplastic agents appears critical to improve clinical outcomes in the management of solid tumors.