Tumor Neovascularization and Developments in Therapeutics

AIM2 Inflammasome in Tumor Cells as a Biomarker for Predicting the Treatment Response to Antiangiogenic Therapy in Epithelial Ovarian Cancer Patients

Antiangiogenic therapy, such as bevacizumab (BEV), has improved progression-free survival (PFS) and overall survival (OS) in high-risk patients with epithelial ovarian cancer (EOC) according to several clinical trials. Clinically, no reliable molecular biomarker is available to predict the treatment response to antiangiogenic therapy. Immune-related proteins can indirectly contribute to angiogenesis by regulating stromal cells in the tumor microenvironment. This study was performed to search biomarkers for prediction of the BEV treatment response in EOC patients. We conducted a hospital-based retrospective study from March 2013 to May 2020. Tissues from 78 Taiwanese patients who were newly diagnosed with EOC and peritoneal serous papillary carcinoma (PSPC) and received BEV therapy were collected. We used immunohistochemistry (IHC) staining and analyzed the expression of these putative biomarkers (complement component 3 (C3), complement component 5 (C5), and absent in melanoma 2 (AIM2)) based on the staining area and intensity of the color reaction to predict BEV efficacy in EOC patients. The immunostaining scores of AIM2 were significantly higher in the BEV-resistant group (RG) than in the BEV-sensitive group (SG) (355.5 vs. 297.1, p < 0.001). A high level of AIM2 (mean value > 310) conferred worse PFS after treatment with BEV than a low level of AIM2 (13.58 vs. 19.36 months, adjusted hazard ratio (HR) = 4.44, 95% confidence interval (CI) = 2.01–9.80, p < 0.001). There were no significant differences in C3 (p = 0.077) or C5 (p = 0.326) regarding BEV efficacy. AIM2 inflammasome expression can be a histopathological biomarker to predict the antiangiogenic therapy benefit in EOC patients. The molecular mechanism requires further investigation.

Modulation of the tumor microenvironment (TME) by melatonin

The tumor microenvironment (TME) includes a number of non-cancerous cells that affect cancer cell survival. Although CD8+ T lymphocytes and natural killer (NK) cells suppress tumor growth through induction of cell death in cancer cells, there are various immunosuppressive cells such as regulatory T cells (Tregs), tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), etc., which drive cancer cell proliferation. These cells may also support tumor growth and metastasis by stimulating angiogenesis, epithelial-mesenchymal transition (EMT), and resistance to apoptosis. Interactions between cancer cells and other cells, as well as molecules released into EMT, play a key role in tumor growth and suppression of antitumoral immunity. Melatonin is a natural hormone that may be found in certain foods and is also available as a drug. Melatonin has been demonstrated to modulate cell activity and the release of cytokines and growth factors in TME. The purpose of this review is to explain the cellular and molecular mechanisms of cancer cell resistance as a result of interactions with TME. Next, we explain how melatonin affects cells and interactions within the TME.

Anti-Cancer and Anti-Angiogenesis Activities of Zerumbone Isolated from Zingiber Zerumbet - A Systematic Review

Significant number of literatures has demonstrated the antiproliferative effect of Zerumbone and its role as anti-angiogenesis. The aims of this systematic review were to assess the anti-cancer effects of Zerumbone and the role of its antiangiogenic properties in treating cancer. Relevant articles were selected based on specific inclusion criteria. Articles chosen for this systematic review were between January 2008 and December 2018. Relevant articles were identified through an extensive search in Science Direct, PubMed, Google Scholar and Scopus. The literature searches of the electronic databases combined the following key words: anti-angiogenic, anticancer, Zerumbone and Zingiber zerumbet. Studies chosen for this review includes the following designs in vitro, in vivo and ex vivo. The initial literature search obtained a total of 352 related records and the final number of studies that met the inclusion criteria in the current review was 43 studies. In vitro studies were the commonest study design. Evidently, Zerumbone demonstrate a potential antiproliferative and antiangiogenic. The antiproliferative activities of Zerumbone was shown to induce by different signalling pathway. Zerumbone through its antiangiogenic effect play a great role in reducing invasion and metastasis. Some selected studies on Zerumbone were found to plague with limitation such as lack of toxic threshold value which may be needed for the clinical trials on this compound.

A Novel Orthotopic Liver Cancer Model for Creating a Human-like Tumor Microenvironment

Simple Summary

Hepatocellular carcinoma is the most common form of liver cancer. The lack of models that resemble actual tumor development in patients, limits the research to improve the diagnosis rate and develop new treatments. This study describes a novel mouse model that involves organoid formation and an implantation technique. This mouse model shares human genetic profiles and factors around the tumor, resembling the actual tumor development in patients. We demonstrate the roles of different cell types around the tumor, in promoting tumor growth, using this model. This model will be useful to understand the tumor developmental process, drug testing, diagnosis, prognosis, and treatment development.

Abstract

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. This study aims to develop a new method to generate an HCC mouse model with a human tumor, and imitates the tumor microenvironment (TME) of clinical patients. Here, we have generated functional, three-dimensional sheet-like human HCC organoids in vitro, using luciferase-expressing Huh7 cells, human iPSC-derived endothelial cells (iPSC-EC), and human iPSC-derived mesenchymal cells (iPSC-MC). The HCC organoid, capped by ultra-purified alginate gel, was implanted into the disrupted liver using an ultrasonic homogenizer in the immune-deficient mouse, which improved the survival and engraftment rate. We successfully introduced different types of controllable TME into the model and studied the roles of TME in HCC tumor growth. The results showed the role of the iPSC-EC and iPSC-MC combination, especially the iPSC-MC, in promoting HCC growth. We also demonstrated that liver fibrosis could promote HCC tumor growth. However, it is not affected by non-alcoholic fatty liver disease. Furthermore, the implantation of HCC organoids to humanized mice demonstrated that the immune response is important in slowing down tumor growth at an early stage. In conclusion, we have created an HCC model that is useful for studying HCC development and developing new treatment options in the future.

Peripheral neurovascular link: an overview of interactions and in vitro models

Nerves and blood vessels (BVs) establish extensive arborized networks to innervate tissues and deliver oxygen/metabolic support. Developmental cues direct the formation of these intricate and often overlapping patterns, which reflect close interactions within the peripheral neurovascular system. Besides the mutual dependence to survive and function, nerves and BVs share several receptors and ligands, as well as principles of differentiation, growth and pathfinding. Neurovascular (NV) interactions are maintained in adult life and are essential for certain regenerative mechanisms, such as wound healing. In pathological situations (e.g., type 2 diabetes mellitus), the NV system can be severely perturbed and become dysfunctional. Unwanted neural growth and vascularization are also associated with the progression of some pathologies, such as cancer and endometriosis. In this review, we describe the fundamental NV interactions in development, highlighting the similarities between both networks and wiring mechanisms. We also describe the NV contribution to regenerative processes and potential pathological dysfunctions. Finally, we provide an overview of current in vitro models used to replicate and investigate the NV ecosystem, addressing present limitations and future perspectives.

The Rapidly Evolving Landscape of First-Line Targeted Therapy in Metastatic Urothelial Cancer: A Systematic Review

BACKGROUND

Metastatic urothelial carcinoma (mUC) historically is treated with first-line platinum-based combination chemotherapy, preferably cisplatin plus gemcitabine whenever possible. In recent years, multiple classes of targeted therapy have demonstrated benefit, with some receiving approval in mUC. This review will summarize phase III efficacy and safety data for targeted agents, principally immune checkpoint inhibitors (ICIs), as either first-line or first-line switch-maintenance therapy for mUC and interpret these findings in the context of the current treatment landscape.

MATERIALS AND METHODS

Published and presented phase III data on targeted therapy for the first-line or first-line switch-maintenance treatment of mUC were identified using the key search terms "targeted therapy" AND "urothelial carcinoma" AND "advanced" OR respective aliases according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Of the six eligible phase III targeted therapy trials, two assessing ICIs met their primary endpoints in platinum-eligible patients. First-line ICI plus chemotherapy combinations have not improved overall survival (OS), although final OS results of the IMVigor 130 trial are pending. Switch-maintenance using an ICI in patients achieving at least stable disease following platinum-based chemotherapy statistically significantly improved OS (21.4 vs. 14.3 months, hazard ratio, 0.69; 95% confidence interval, 0.56-0.86; p = .001). Current sequencing options for mUC include first-line platinum-based chemotherapy with a switch to ICI either immediately or upon disease progression.

CONCLUSION

Recent targeted therapy trials have expanded ICI sequencing options for mUC. The treatment landscape is likely to evolve rapidly, with results from multiple phase III trials expected in the next 5 years.

IMPLICATIONS FOR PRACTICE

Multiple classes of targeted agents are approved for use in metastatic urothelial carcinoma (mUC). Six phase III trials have recently provided insight on the benefit of these agents in the first-line setting. In platinum-eligible patients, immune checkpoint inhibitors (ICIs) combined with first-line platinum-based chemotherapy failed to demonstrate improved survival, although ICI monotherapy as switch-maintenance significantly improved overall survival in patients with mUC who had achieved at least stable disease following first-line platinum-based chemotherapy. In patients ineligible for any chemotherapy, pembrolizumab, atezolizumab, or pembrolizumab in combination with enfortumab vedotin may be options.

Emerging Importance of Chemokine Receptor CXCR4 and Its Ligand in Liver Disease

Chemokine receptors are members of the G protein-coupled receptor superfamily, which together with chemokine ligands form chemokine networks to regulate various cellular functions, immune and physiological processes. These receptors are closely related to cell movement and thus play a vital role in several physiological and pathological processes that require regulation of cell migration. CXCR4, one of the most intensively studied chemokine receptors, is involved in many functions in addition to immune cells recruitment and plays a pivotal role in the pathogenesis of liver disease. Aberrant CXCR4 expression pattern is related to the migration and movement of liver specific cells in liver disease through its cross-talk with a variety of significant cell signaling pathways. An in-depth understanding of CXCR4-mediated signaling pathway and its role in liver disease is critical to identifying potential therapeutic strategies. Current therapeutic strategies for liver disease mainly focus on regulating the key functions of specific cells in the liver, in which the CXCR4 pathway plays a crucial role. Multiple challenges remain to be overcome in order to more effectively target CXCR4 pathway and identify novel combination therapies with existing strategies. This review emphasizes the role of CXCR4 and its important cell signaling pathways in the pathogenesis of liver disease and summarizes the targeted therapeutic studies conducted to date.

TEM8 marks neovasculogenic tumor-initiating cells in triple-negative breast cancer

Enhanced neovasculogenesis, especially vasculogenic mimicry (VM), contributes to the development of triple-negative breast cancer (TNBC). Breast tumor-initiating cells (BTICs) are involved in forming VM; however, the specific VM-forming BTIC population and the regulatory mechanisms remain undefined. We find that tumor endothelial marker 8 (TEM8) is abundantly expressed in TNBC and serves as a marker for VM-forming BTICs. Mechanistically, TEM8 increases active RhoC level and induces ROCK1-mediated phosphorylation of SMAD5, in a cascade essential for promoting stemness and VM capacity of breast cancer cells. ASB10, an estrogen receptor ERα trans-activated E3 ligase, ubiquitylates TEM8 for degradation, and its deficiency in TNBC resulted in a high homeostatic level of TEM8. In this work, we identify TEM8 as a functional marker for VM-forming BTICs in TNBC, providing a target for the development of effective therapies against TNBC targeting both BTIC self-renewal and neovasculogenesis simultaneously.

Vasculogenic mimicry (VM) contributes to the development of triple-negative breast cancer. In this study, the authors show that TEM8 is expressed in VM-forming breast cancer stem cells and it promotes stemness and VM differentiation capacity through a RhoC/ROCK1/SMAD5 axis

The Effects on Angiogenesis of Relevant Inorganic Chemotherapeutics

Angiogenesis is a key process allowing the formation of blood vessels. It is crucial for all the tissues and organs, ensuring their function and growth. Angiogenesis is finely controlled by several mechanisms involving complex interactions between pro- or antiangiogenic factors, and an imbalance in this control chain may result in pathological conditions. Metals as copper, zinc and iron cover an essential role in regulating angiogenesis, thus therapies having physiological metals as target have been proposed. In addition, some complexes of heavier metal ions (e.g., Pt, Au, Ru) are currently used as established or experimental anticancer agents targeting genomic or non-genomic targets. These molecules may affect the angiogenic mechanisms determining different effects that have been only poorly and non-systematically investigated so far. Accordingly, in this review article, we aim to recapitulate the impact on the angiogenic process of some reference anticancer drugs, and how it is connected to the overall pharmacological effects. In addition, we highlight how the activity of these drugs can be related to the role of biological essential metal ions. Overall, this may allow a deeper description and understanding of the antineoplastic activity of both approved or experimental metal complexes, providing important insights for the synthesis of new inorganic drugs able to overcome resistance and recurrence phenomena.

Targeting Tumor Immunosuppressive Microenvironment for the Prevention of Hepatic Cancer: Applications of Traditional Chinese Medicines in Targeted Delivery

Traditional Chinese Medicine (TCM) is one of the ancient and most accepted alternative medicinal systems in the world for the treatment of health ailments. World Health Organization recognizes TCM as one of the primary healthcare practices followed across the globe. TCM utilizes a holistic approach for the diagnosis and treatment of cancers. The tumor microenvironment (TME) surrounds cancer cells and plays pivotal roles in tumor development, growth, progression, and therapy resistance. TME is a hypoxic and acidic environment that includes immune cells, pericytes, fibroblasts, endothelial cells, various cytokines, growth factors, and extracellular matrix components. Targeting TME using targeted drug delivery and nanoparticles is an attractive strategy for the treatment of solid tumors and recently has received significant research attention under precise medicine concept. TME plays a pivotal role in the overall survival and metastasis of a tumor by stimulating cell proliferation, preventing the tumor clearance by the immune cells, enhancing the oncogenic potential of the cancer cells, and promoting tumor invasion. Hepatocellular Carcinoma (HCC) is one of the major causes of cancer-associated deaths affecting millions of individuals worldwide each year. TCM herbs contain several bioactive phytoconstituents with a broad range of biological, physiological, and immunological effects on the system. Several TCM herbs and their monomers have shown inhibitory effects in HCC by controlling the TME. This study reviews the fundamentals and applications of targeting strategies for immunosuppressing TME to treat cancers. This study focuses on TME targeting strategies using TCM herbs and the molecular mechanisms of several TCM herbs and their monomers on controlling TME.

New prophylaxis strategies to reduce the risk of thromboembolism in cancer

INTRODUCTION

: Patients with cancer are at risk of thrombotic events, mainly deep vein thrombosis and/or pulmonary embolism. The thrombosis risk is generally 4-6 times higher than in a healthy population and depends on factors related to patient characteristics, tumor factors, and treatment-related factors. The decision-making for prophylactic anticoagulation is individualized according to the relative risks and benefits. The VTE risk has been quantified using different assessment scores. In recent years, an effort has been made to establish "risk assessment models" specifically for patients undergoing chemotherapy.

AREAS COVERED

This article reviews current data and ongoing research on predictive factors involved in cancer-related thrombosis and it is highlighted the currently suggested strategies for prophylaxis. Several trials that compared the two treatment options, direct factor Xa inhibitor or LMWH, with placebo and not each other are discussed. In this article, was analyzed the safety and efficacy features that led several international organizations such as ASCO, NCCN, and others, to issue guidelines for the prophylaxis and treatment of patients at high risk of thrombosis by using LMWH, fondaparinux and DOACs.

EXPERT OPINION

ASCO, NCCN, and other international organizations recommend thromboprophylaxis in high risk patients. However, further investigation is needed to define better biomarkers for more accurate identification of cancer patients that will benefit from anticoagulant treatment.

Apoptotic Effects of N-(2-Hydroxyphenyl)-2-Propylpentanamide on U87-MG and U-2 OS Cells and Antiangiogenic Properties

BACKGROUND AND OBJECTIVE

Histone Deacetylases (HDACs) are important therapeutic targets for many types of human cancers. A derivative of valproic acid, N-(2-hydroxyphenyl)-2-propylpentanamide (HOAAVPA), has antiproliferative properties on some cancer cell lines and inhibits the HDAC1 isoform.

MATERIALS AND METHODS

In this work, HO-AAVPA was tested as an antiproliferative agent in U87-MG (human glioblastoma) and U-2 OS cells (human osteosarcoma), which are types of cancer that are difficult to treat, and its antiangiogenic properties were explored.

RESULTS

HO-AAVPA had antiproliferative effects at 48h with an IC₅₀=0.655mM in U87-MG cells and an IC₅₀=0.453mM in U-2 OS cells. Additionally, in the colony formation assay, HO-AAVPA decreased the number of colonies by approximately 99% in both cell lines and induced apoptosis by 31.3% in the U-2 OS cell line and by 78.2% in the U87-MG cell line. Additionally, HO-AAVPA reduced the number of vessels in Chorioallantoic Membranes (CAMs) by approximately 67.74% and IL-6 levels in both cell lines suggesting that the biochemical mechanism on cancer cell of HO-AAVPA is different compared to VPA.

CONCLUSION

HO-AAVPA has antiproliferative effects on glioblastoma and osteosarcoma and antiangiogenic properties.

Disrupting tumour vasculature and recruitment of aPDL1-loaded platelets control tumour metastasis

Although therapies of cancer are advancing, it remains challenging for therapeutics to reach the sites of metastasis, which accounts for majority of cancer associated death. In this study, we have developed a strategy that guides an anti-programmed cell death-ligand 1 (aPDL1) antibody to accumulate in metastatic lesions to promote anti-tumour immune responses. Briefly, we have developed a combination in which Vadimezan disrupts tumour blood vessels of tumour metastases and facilitates the recruitment and activation of adoptively transferred aPDL1-conjugated platelets. In situ activated platelets generate aPDL1-decorated platelet-derived microparticles (PMP) that diffuse within the tumour and elicit immune responses. The proposed combination increases 10-fold aPDL1 antibody accumulation in lung metastases as compared to the intravenous administration of the antibody and enhances the magnitude of immune responses leading to improved antitumour effects.

Cancer metastasis is the leading cause of death in patients, here, the authors show disrupting tumor vasculature could recruit and activate anti-PD-L1 engineered platelet at metastatic tumor sites to block the PD-1/PD-L1 crosstalk and enhance the anticancer immunotherapy.

Molecular Mechanism of Autophagy and Its Regulation by Cannabinoids in Cancer

Simple Summary

This review examines the complex function of autophagy in malignancy and explores its regulation by cannabinoids in different cancers. Autophagy is an important process in the maintenance of cellular homeostasis, through the degradation and recycling of cytoplasmic constituents. The action of autophagy is highly dependent on tumour stage and type and the receptors with which ligands interact. Cannabinoids are growingly being acknowledged for their anticancer activities and are known to stimulate several mechanisms such as apoptosis and autophagy. Better understanding the mechanism of action behind autophagy and its regulation by cannabinoids will allow the development of novel cancer therapeutics.

Abstract

Autophagy is a “self-degradation” process whereby malfunctioned cytoplasmic constituents and protein aggregates are engulfed by a vesicle called the autophagosome, and subsequently degraded by the lysosome. Autophagy plays a crucial role in sustaining protein homeostasis and can be an alternative source of energy under detrimental circumstances. Studies have demonstrated a paradoxical function for autophagy in cancer, displaying both tumour suppressive and tumour promotive roles. In early phases of tumour development autophagy promotes cancer cell death. In later phases, autophagy enables cancer cells to survive and withstand therapy. Cannabinoids, which are derivatives of the Cannabis sativa L. plant, have shown to be associated with autophagy induction in cells. There is an emerging interest in studying the signalling pathways involved in cannabinoid-induced autophagy and their potential application in anticancer therapies. In this review, the molecular mechanisms involved in the autophagy degradation process will be discussed. This review also highlights a role for autophagy in cancer progression, with cannabinoid-induced autophagy presenting a novel strategy for anticancer therapy.

Loss of endothelial glucocorticoid receptor promotes angiogenesis via upregulation of Wnt/β-catenin pathway

Objective

The glucocorticoid receptor (GR) is a member of the nuclear receptor family that controls key biological processes in the cardiovascular system and has recently been shown to modulate Wnt signaling in endothelial cells. Wnt/β-catenin signaling has been demonstrated to be crucial in the process of angiogenesis. In the current study, we studied whether GR could regulate angiogenesis via the Wnt/β-catenin pathway.

Approach and Resultsa

Key components of the Wnt/β-catenin pathway were evaluated using quantitative PCR and Western blot in the presence or absence of GR. Enhanced angiogenesis was found in GR deficiency in vitro and confirmed with cell viability assays, proliferation assays and tube formation assays. Consistent with these in vitro findings, endothelial cell-specific GR loss GR in vivo promoted angiogenesis in both a hind limb ischemia model and sponge implantation assay. Results were further verified in a novel mouse model lacking endothelial LRP5/6, a key receptor in canonical Wnt signaling, and showed substantially suppressed angiogenesis using these same in vitro and in vivo assays. To further investigate the mechanism of GR regulation of Wnt signaling, autophagy flux was investigated in endothelial cells by visualizing auto phagolysosomes as well as by assessing P62 degradation and LC3B conversion. Results indicated that potentiated autophagy flux participated in GR-Wnt regulation.

Conclusions

Lack of endothelial GR triggers autophagy flux, leads to activation of Wnt/β-catenin signaling and promotes angiogenesis. There may also be a synergistic interaction between autophagy and Wnt/β-catenin signaling.

Supplementary Information

The online version of this article (10.1007/s10456-021-09773-x) contains supplementary material, which is available to authorized users.

Pathological angiogenesis and inflammation in tissues

The role of angiogenesis in the growth of organs and tumors is widely recognized. Vascular-organ interaction is a key mechanism and a concept that enables an understanding of all biological phenomena and normal physiology that is essential for human survival under pathological conditions. Recently, vascular endothelial cells have been classified as a type of innate immune cells that are dependent on the pathological situations. Moreover, inflammatory cytokines and signaling regulators activated upon exposure to infection or various stresses play crucial roles in the pathological function of parenchymal cells, peripheral immune cells, stromal cells, and cancer cells in tissues. Therefore, vascular-organ interactions as a vascular microenvironment or tissue microenvironment under physiological and pathological conditions are gaining popularity as an interesting research topic. Here, we review vascular contribution as a major factor in microenvironment homeostasis in the pathogenesis of normal as well as cancerous tissues. Furthermore, we suggest that the normalization strategy of pathological angiogenesis could be a promising therapeutic target for various diseases, including cancer.

3D histopathology of human tumours by fast clearing and ultramicroscopy

Here, we describe a novel approach that allows pathologists to three-dimensionally analyse malignant tissues, including the tumour-host tissue interface. Our visualization technique utilizes a combination of ultrafast chemical tissue clearing and light-sheet microscopy to obtain virtual slices and 3D reconstructions of up to multiple centimetre sized tumour resectates. For the clearing of tumours we propose a preparation technique comprising three steps: (a) Fixation and enhancement of tissue autofluorescence with formalin/5-sulfosalicylic acid. (b) Ultrafast active chemical dehydration with 2,2-dimethoxypropane and (c) refractive index matching with dibenzyl ether at up to 56 °C. After clearing, the tumour resectates are imaged. The images are computationally post-processed for contrast enhancement and artefact removal and then 3D reconstructed. Importantly, the sequence a–c is fully reversible, allowing the morphological correlation of one and the same histological structures, once visualized with our novel technique and once visualized by standard H&E- and IHC-staining. After reverting the clearing procedure followed by standard H&E processing, the hallmarks of ductal carcinoma in situ (DCIS) found in the cleared samples could be successfully correlated with the corresponding structures present in H&E and IHC staining. Since the imaging of several thousands of optical sections is a fast process, it is possible to analyse a larger part of the tumour than by mechanical slicing. As this also adds further information about the 3D structure of malignancies, we expect that our technology will become a valuable addition for histological diagnosis in clinical pathology.

Implications of flavonoids as potential modulators of cancer neovascularity

PURPOSE

The formation of new blood vessels from previous ones, angiogenesis, is critical in tissue repair, expansion or remodeling in physiological processes and in various pathologies including cancer. Despite that, the development of anti-angiogenic drugs has great potential as the treatment of cancer faces many problems such as development of the resistance to treatment or an improperly selected therapy approach. An evaluation of predictive markers in personalized medicine could significantly improve treatment outcomes in many patients.

METHODS

This comprehensive review emphasizes the anticancer potential of flavonoids mediated by their anti-angiogenic efficacy evaluated in current preclinical and clinical cancer research.

RESULTS AND CONCLUSION

Flavonoids are important groups of phytochemicals present in common diet. Flavonoids show significant anticancer effects. The anti-angiogenic effects of flavonoids are currently a widely discussed topic of preclinical cancer research. Flavonoids are able to regulate the process of tumor angiogenesis through modulation of signaling molecules such as VEGF, MMPs, ILs, HIF or others. However, the evaluation of the anti-angiogenic potential of flavonoids within the clinical studies is not frequently discussed and is still of significant scientific interest.

Exosomes in Angiogenesis and Anti-angiogenic Therapy in Cancers

Angiogenesis is the process through which new blood vessels are formed from pre-existing ones. Exosomes are involved in angiogenesis in cancer progression by transporting numerous pro-angiogenic biomolecules like vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), and microRNAs. Exosomes promote angiogenesis by suppressing expression of factor-inhibiting hypoxia-inducible factor 1 (HIF-1). Uptake of tumor-derived exosomes (TEX) by normal endothelial cells activates angiogenic signaling pathways in endothelial cells and stimulates new vessel formation. TEX-driven cross-talk of mesenchymal stem cells (MSCs) with immune cells blocks their anti-tumor activity. Effective inhibition of tumor angiogenesis may arrest tumor progression. Bevacizumab, a VEGF-specific antibody, was the first antiangiogenic agent to enter the clinic. The most important clinical problem associated with cancer therapy using VEGF- or VEFGR-targeting agents is drug resistance. Combined strategies based on angiogenesis inhibitors and immunotherapy effectively enhances therapies in various cancers, but effective treatment requires further research.

Tumor Genotype Is Shaping Immunophenotype and Responses to Immune Checkpoint Inhibitors in Solid Tumors

A major breakthrough in cancer treatment was ushered in by the development of immune checkpoint blockade therapy such as anti-CTLA4 antibody and anti-PD-1 and anti-programmed cell death-ligand 1 antibodies that are now approved for use in an increasing number of malignancies. Despite the relative success of immune checkpoint inhibitors with certain tumor types, many patients still fail to respond to such therapies, and the field is actively trying to understand the mechanisms of resistance, intrinsic or acquired, to immune checkpoint blockade. Herein, we discuss the roles that somatic genomic mutations in oncogenic pathways play in immune editing, as well as some of the current approaches toward improving response to immunotherapy.

Porous Polymeric Microspheres With Controllable Pore Diameters for Tissue Engineered Lung Tumor Model Development

Complex cell cultures are more representative of in vivo conditions than conventionally used monolayer cultures, and are hence being investigated for predictive screening of therapeutic agents. Poly lactide co-glycolide (PLGA) polymer is frequently used in the development of porous substrates for complex cell culture. Substrates or scaffolds with highly interconnected, micrometric pores have been shown to positively impact tissue model formation by enhancing cell attachment and infiltration. We report a novel alginate microsphere (AMS)-based controlled pore formation method for the development of porous, biodegradable PLGA microspheres (PPMS), for tissue engineered lung tumor model development. The AMS porogen, non-porous PLGA microspheres (PLGAMS) and PPMS had spherical morphology (mean diameters: 10.3 ± 4, 79 ± 21.8, and 103 ± 30 μm, respectively). The PPMS had relatively uniform pores and a porosity of 45.5%. Degradation studies show that PPMS effectively maintained their structural integrity with time whereas PLGAMS showed shrunken morphology. The optimized cell seeding density on PPMS was 25 × 103 cells/mg of particles/well. Collagen coating on PPMS significantly enhanced the attachment and proliferation of co-cultures of A549 lung adenocarcinoma and MRC-5 lung fibroblast cells. Preliminary proof-of-concept drug screening studies using mono- and combination anti-cancer therapies demonstrated that the tissue-engineered lung tumor model had a significantly higher resistance to the tested drugs than the monolayer co-cultures. These studies indicate that the PPMS with controllable pore diameters may be a suitable platform for the development of complex tumor cultures for early in vitro drug screening applications.

Endothelial Progenitors in the Tumor Microenvironment

Tumor vascularization refers to the formation of new blood vessels within a tumor and is considered one of the hallmarks of cancer. Tumor vessels supply the tumor with oxygen and nutrients, required to sustain tumor growth and progression, and provide a gateway for tumor metastasis through the blood or lymphatic vasculature. Blood vessels display an angiocrine capacity of supporting the survival and proliferation of tumor cells through the production of growth factors and cytokines. Although tumor vasculature plays an essential role in sustaining tumor growth, it represents at the same time an essential way to deliver drugs and immune cells to the tumor. However, tumor vasculature exhibits many morphological and functional abnormalities, thus resulting in the formation of hypoxic areas within tumors, believed to represent a mechanism to maintain tumor cells in an invasive state.Tumors are vascularized through a variety of modalities, mainly represented by angiogenesis, where VEGF and other members of the VEGF family play a key role. This has represented the basis for the development of anti-VEGF blocking agents and their use in cancer therapy: however, these agents failed to induce significant therapeutic effects.Much less is known about the cellular origin of vessel network in tumors. Various cell types may contribute to tumor vasculature in different tumors or in the same tumor, such as mature endothelial cells, endothelial progenitor cells (EPCs), or the same tumor cells through a process of transdifferentiation. Early studies have suggested a role for bone marrow-derived EPCs; these cells do not are true EPCs but myeloid progenitors differentiating into monocytic cells, exerting a proangiogenic effect through a paracrine mechanism. More recent studies have shown the existence of tissue-resident endothelial vascular progenitors (EVPs) present at the level of vessel endothelium and their possible involvement as cells of origin of tumor vasculature.

Photodynamic therapy of pancreatic cancer: Where have we come from and where are we going?

Photodynamic therapy (PDT) is a potential adjuvant therapy in pancreatic cancer with several advantages. Mechanistically, pancreatic cancer PDT can induce apoptosis and necrosis of pancreatic cancer cells and lead to vascular damage and enhance anti-tumor immune response in tumor tissues. However, limitations of current photosensitizers such as limited penetration depth, poor targeted therapy and inadequate reactive oxygen species (ROS) generation still exist. Recently, several novel photosensitizers have been reported to break through limits in pancreatic cancer PDT. Methods combined with biomedical engineering, materialogy and chemical engineering have been employed to overcome the difficulties and to realize targeted therapy. Preclinical and clinical trials also preliminarily confirmed the technical feasibility and safety of pancreatic cancer PDT. Therefore, PDT may be potential to be used as an effective adjuvant therapy in pancreatic cancer multimodality therapy. This review will give an overview about pancreatic cancer PDT from basic experimental studies, preclinical and clinical application to future direction of pancreatic cancer PDT.

Co-Culturing of Endothelial and Cancer Cells in a Nanofibrous Scaffold-Based Two-Layer System

Angiogenesis is critical for local tumor growth. This study aimed to develop a three-dimensional two-layer co-culture system to investigate effects of cancer cells on the growth of endothelial cells (ECs). Poly(ε-caprolactone) (PCL) nanofibrous membranes were generated via electrospinning of PCL in chloroform (C-PCL-M) and chloroform and dimethylformamide (C/DMF-PCL-M). We assembled a two-layer co-culture system using C-PCL-M and C/DMF-PCL-M for EC growth in the upper layer with co-cultured cancer cells in the lower layer. In the absence of vascular endothelial growth factor (VEGF), growth of bEND.3 ECs decreased on C/DMF-PCL-M but not on C-PCL-M with time. Growth of bEND.3 cells on C/DMF-PCL-M was enhanced through co-culturing of CT26 cancer cells and enhanced growth of bEND.3 cells was abrogated with anti-VEGF antibodies and sorafenib. However, EA.hy926 ECs displayed steady growth and proliferation on C/DMF-PCL-M, and their growth was not further increased through co-culturing of cancer cells. Moreover, chemical hypoxia in CT26 cancer cells upon treatment with CoCl₂ enhanced the growth of co-cultured bEND.3 cells in the two-layer system. Thus, EC growth on the nanofibrous scaffold is dependent on the types of ECs and composition of nanofibers and this co-culture system can be used to analyze EC growth induced by cancer cells.

Assessment of postoperative adjuvant treatment using toceranib phosphate against adenocarcinoma in dogs

Background

Toceranib phosphate (TOC) could be made widely available for treating tumors in dogs if evidence shows that TOC inhibits recurrence after surgery.

Objectives

To investigate how postoperative adjuvant treatment with TOC modulates the tumor microenvironment (TME), by assessing effects on angiogenic activity, tumor‐infiltrating regulatory T cells (Tregs), and intratumoral hypoxia.

Animals

Ninety‐two client‐owned dogs were included: 28 with apocrine gland anal sac adenocarcinoma, 24 with small intestinal adenocarcinoma, 22 with lung adenocarcinoma, and 18 with renal cell carcinoma.

Methods

Retrospective, multicenter study comparing time to progression (TTP) between 42 dogs treated by surgery and TOC and 50 dogs treated by surgery alone. Differences were analyzed in the expression of vascular endothelial growth factor receptor‐2 (VEGFR2) and the number of Foxp3⁺ Tregs and hypoxia‐inducible factor (HIF)‐1α⁺ cells in tumor tissues sampled at the first and second (recurrence) surgeries.

Results

Median TTP for dogs treated by surgery and TOC (360 days) was higher than that for dogs treated by surgery alone (298 days; hazard ratio, 0.82; 95% confidence interval [CI], 0.65‐0.96; P = .02). In dogs treated by surgery and TOC, VEGFR2 expression and the number of Tregs and HIF‐1α⁺ cells were significantly lower in tissues sampled at the second surgery than in those sampled after the first surgery. In dogs treated by surgery alone, significant differences were found between samples from the 2 surgeries.

Conclusions and Clinical Importance

Toceranib phosphate could prove to be a useful postoperative adjuvant treatment because of its modulation of the TME.

The biological mechanism involved in anticancer properties of amniotic membrane

The main role of amniotic membrane (AM), or amnion, is to protect the fetus from drying out and create an appropriate environment for its growth. AM is also a suitable candidate for the treatment of various diseases due to its unique characteristics. In recent years, a new line of research has focused on the anticancer properties of amnion and its potential use in cancer treatment. The in vitro and in vivo studies indicate the anti-proliferative and proapoptotic activities, as well as the angioregulatory and immunomodulatory properties of the amniotic membrane. However, the exact mechanism and molecular basis of these anticancer effects of AM are not fully elucidated. This paper presents an overview of the latest findings and knowledge about the anticancer effects of AM and its underlying molecular mechanisms, which is crucial for the application of amnion in cancer therapy.

The Acidic Tumor Microenvironment as a Driver of Cancer

Acidic metabolic waste products accumulate in the tumor microenvironment because of high metabolic activity and insufficient perfusion. In tumors, the acidity of the interstitial space and the relatively well-maintained intracellular pH influence cancer and stromal cell function, their mutual interplay, and their interactions with the extracellular matrix. Tumor pH is spatially and temporally heterogeneous, and the fitness advantage of cancer cells adapted to extracellular acidity is likely particularly evident when they encounter less acidic tumor regions, for instance, during invasion. Through complex effects on genetic stability, epigenetics, cellular metabolism, proliferation, and survival, the compartmentalized pH microenvironment favors cancer development. Cellular selection exacerbates the malignant phenotype, which is further enhanced by acid-induced cell motility, extracellular matrix degradation, attenuated immune responses, and modified cellular and intercellular signaling. In this review, we discuss how the acidity of the tumor microenvironment influences each stage in cancer development, from dysplasia to full-blown metastatic disease.

Regulation Networks Driving Vasculogenic Mimicry in Solid Tumors

Vasculogenic mimicry (VM) is a mechanism whereby cancer cells form microvascular structures similar to three-dimensional channels to provide nutrients and oxygen to tumors. Unlike angiogenesis, VM is characterized by the development of new patterned three-dimensional vascular-like structures independent of endothelial cells. This phenomenon has been observed in many types of highly aggressive solid tumors. The presence of VM has also been associated with increased resistance to chemotherapy, low survival, and poor prognosis. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are non-coding RNAs that regulate gene expression at the post-transcriptional level through different pathways. In recent years, these tiny RNAs have been shown to be expressed aberrantly in different human malignancies, thus contributing to the hallmarks of cancer. In this context, miRNAs and lncRNAs can be excellent biomarkers for diagnosis, prognosis, and the prediction of response to therapy. In this review, we discuss the role that the tumor microenvironment and the epithelial-mesenchymal transition have in VM. We include an overview of the mechanisms of VM with examples of diverse types of tumors. Finally, we describe the regulation networks of lncRNAs-miRNAs and their clinical impact with the VM. Knowing the key genes that regulate and promote the development of VM in tumors with invasive, aggressive, and therapy-resistant phenotypes will facilitate the discovery of novel biomarker therapeutics against cancer as well as tools in the diagnosis and prognosis of patients.

Radiation Dosimetry and Biodistribution of 68Ga-FAPI-46 PET Imaging in Cancer Patients

Targeting cancer-associated fibroblasts (CAFs) has become an attractive goal for diagnostic imaging and therapy because they can constitute as much as 90% of a tumor mass. The serine protease fibroblast activation protein (FAP) is overexpressed selectively in CAFs, drawing interest in FAP as a stromal target. The quinoline-based FAP inhibitor (FAPI) PET tracer ⁶⁸Ga-FAPI-04 has been previously shown to yield high tumor-to-background ratios (TBRs) in patients with various cancers. Recent developments toward an improved compound for therapeutic application have identified FAPI-46 as a promising agent because of an increased tumor retention time in comparison with FAPI-04. Here, we present a PET biodistribution and radiation dosimetry study of ⁶⁸Ga-FAPI-46 in cancer patients. Methods: Six patients with different cancers underwent serial ⁶⁸Ga-FAPI-46 PET/CT scans at 3 time points after radiotracer injection: 10 min, 1 h, and 3 h. The source organs consisted of the kidneys, bladder, liver, heart, spleen, bone marrow, uterus, and remainder of body. OLINDA/EXM software, version 1.1, was used to fit and integrate the kinetic organ activity data to yield total-body and organ time-integrated activity coefficients and residence times and, finally, organ-absorbed doses. SUVs and TBR were generated from the contoured tumor and source-organ volumes. Spheric volumes in muscle and blood pool were also obtained for TBR (tumor SUV_max/organ SUV_mean). Results: At all time points, average SUV_max was highest in the liver. Tumor and organ SUV_mean decreased over time, whereas TBRs in all organs but the uterus increased. The organs with the highest effective doses were bladder wall (2.41E-03 mSv/MBq), followed by ovaries (1.15E-03 mSv/MBq) and red marrow (8.49E-04 mSv/MBq). The average effective total-body dose was 7.80E-03 mSv/MBq. Conclusion: ⁶⁸Ga-FAPI-46 PET/CT has a favorable dosimetry profile, with an estimated whole-body dose of 5.3 mSv for an administration of 200 MBq (5.4 mCi) of ⁶⁸Ga-FAPI-46 (1.56 ± 0.26 mSv from the PET tracer and 3.7 mSv from 1 low-dose CT scan). The biodistribution study showed high TBRs increasing over time, suggesting high diagnostic performance and favorable tracer kinetics for potential therapeutic applications.

The Hidden Story of Heterogeneous B-raf V600E Mutation Quantitative Protein Expression in Metastatic Melanoma-Association with Clinical Outcome and Tumor Phenotypes

In comparison to other human cancer types, malignant melanoma exhibits the greatest amount of heterogeneity. After DNA-based detection of the BRAF V600E mutation in melanoma patients, targeted inhibitor treatment is the current recommendation. This approach, however, does not take the abundance of the therapeutic target, i.e., the B-raf V600E protein, into consideration. As shown by immunohistochemistry, the protein expression profiles of metastatic melanomas clearly reveal the existence of inter- and intra-tumor variability. Nevertheless, the technique is only semi-quantitative. To quantitate the mutant protein there is a fundamental need for more precise techniques that are aimed at defining the currently non-existent link between the levels of the target protein and subsequent drug efficacy. Using cutting-edge mass spectrometry combined with DNA and mRNA sequencing, the mutated B-raf protein within metastatic tumors was quantitated for the first time. B-raf V600E protein analysis revealed a subjacent layer of heterogeneity for mutation-positive metastatic melanomas. These were characterized into two distinct groups with different tumor morphologies, protein profiles and patient clinical outcomes. This study provides evidence that a higher level of expression in the mutated protein is associated with a more aggressive tumor progression. Our study design, comprised of surgical isolation of tumors, histopathological characterization, tissue biobanking, and protein analysis, may enable the eventual delineation of patient responders/non-responders and subsequent therapy for malignant melanoma.

The role of pigment epithelium-derived factor in protecting against cellular stress

Since its discovery as a neurotrophic factor in retinal pigmented epithelium cells in the late 1980s, there has been an increase in understanding of the role that pigment epithelium-derived factor (PEDF) plays in cellular functions. PEDF plays an important role in mediating cellular protection during exposure to oxidative stress and inflammation by preventing stress-induced angiogenesis and apoptosis. PEDF acts to reduce oxidative stress by promoting mitochondrial stability and by regulating the expression of enzymes involved in ROS accumulation and clearance. PEDF protects against the negative effects of oxidative stress by regulating cell survival pathways and the expression of inflammatory and proangiogenic mediators. PEDF-mediated cellular protection may be of clinical importance in diseases characterised by oxidative stress, chronic inflammation and pathological neovascularization, indicating that targeting PEDF may be a potential focus for therapeutic interventions in chronic diseases. In this review, we provide a historical perspective on the discoveries of PEDF interactions and functions, and discuss recent in vitro, in vivo and clinical findings to provide a current summary of the important protective effects following cellular exposure to stress stimuli and future clinical potential of PEDF.

Vascular architecture mapping for early detection of glioblastoma recurrence

OBJECTIVE

Treatment failure and inevitable tumor recurrence are the main reasons for the poor prognosis of glioblastoma (GB). Gross-total resection at repeat craniotomy for GB recurrence improves patient overall survival but requires early and reliable detection. It is known, however, that even advanced MRI approaches have limited diagnostic performance for distinguishing tumor progression from pseudoprogression. The novel MRI technique of vascular architectural mapping (VAM) provides deeper insight into tumor microvascularity and neovascularization. In this study the authors evaluated the usefulness of VAM for the monitoring of GB patients and quantitatively analyzed the features of neovascularization of early- and progressed-stage GB recurrence.

METHODS

In total, a group of 115 GB patients who received overall 374 follow-up MRI examinations after standard treatment were retrospectively evaluated in this study. The clinical routine MRI (cMRI) protocol at 3 Tesla was extended with the authors’ experimental VAM approach, requiring 2 minutes of extra time for data acquisition. Custom-made MATLAB software was used for calculation of imaging biomarker maps of macrovascular perfusion from perfusion cMRI as well as of microvascular perfusion and architecture from VAM data. Additionally, cMRI data were analyzed by two board-certified radiologists in consensus. Statistical procedures included receiver operating characteristic (ROC) analysis to determine diagnostic performances for GB recurrence detection.

RESULTS

Overall, cMRI showed GB recurrence in 89 patients, and in 28 of these patients recurrence was detected earlier with VAM data, by 1 (20 patients) or 2 (8 patients) follow-up examinations, than with cMRI data. The mean time difference between recurrence detection with VAM and cMRI data was 147 days. During this time period the mean tumor volume increased significantly (p < 0.001) from 9.7 to 26.8 cm3. Quantitative analysis of imaging biomarkers demonstrated microvascular but no macrovascular hyperperfusion in early GB recurrence. Therefore, ROC analysis revealed superior diagnostic performance for VAM compared with cMRI.

CONCLUSIONS

This study demonstrated that the targeted assessment of microvascular features using the VAM technique provided valuable information about early neovascularization activity in recurrent GB that is complementary to perfusion cMRI and may be helpful for earlier and more precise monitoring of patients suffering from GB. This VAM approach is compatible with existing cMRI protocols. Prospective clinical trials are necessary to investigate the clinical usefulness and potential benefit of increased overall survival with the use of VAM in patients with recurrent GB.

Apatinib-loaded nanoparticles inhibit tumor growth and angiogenesis in a model of melanoma

Anti-angiogenic drugs are an effective therapeutic method for the treatment of melanomas. Apatinib is a small-molecule tyrosine kinase inhibitor, which has potent inhibitory activity on tumor angiogenesis. Due to the low water solubility and stability of Apatinib, we aimed to design and develop poly (lactic-co-glycolic acid) (PLGA) and Poloxamer 407 nanoparticles to encapsulate Apatinib (Apa/p NPs) to improve the efficacy of application in melanoma treatment. The size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In vitro proliferation assays were used to assess the capacity of Apa/p NPs to suppress the growth of B16 cells. Furthermore, we constructed melanoma models using C57BL/6 mice, and preliminary evaluation of the effect and mechanism of Apa/p NPs on tumor inhibition was performed in vivo. The results showed that the size of Apa/p NPs averaged 136 ± 0.27 nm and the nanoparticles were evenly dispersed. Moreover, Apa/p NPs significantly inhibited the growth of B16 cells and melanoma tumors, compared with the naked drug treatment and control groups. The protein levels of VEGFR-2, phosphorylated (p)-VEGFR-2 and p-ERK1/2 in tumor tissues were inhibited by Apa/p NP treatment, as detected by Western blot. The results of this study suggested that Apa/p NPs could inhibit the growth of melanoma tumors by inhibiting the phosphorylation and expression of VEGFR-2 and downstream ERK1/2, providing a theoretical basis for the clinical application of Apatinib in the treatment of melanoma.