Anti-angiogenic agents for the treatment of solid tumors: Potential pathways, therapy and current strategies - A review

Intertumoral and intratumoral barriers as approaches for drug delivery and theranostics to solid tumors using stimuli-responsive materials

The solid tumors provide a series of biological barriers in cellular microenvironment for designing drug delivery methods based on advanced stimuli-responsive materials. These intertumoral and intratumoral barriers consist of perforated endotheliums, tumor cell crowding, vascularity, lymphatic drainage blocking effect, extracellular matrix (ECM) proteins, hypoxia, and acidosis. Triggering opportunities have been drawn for solid tumor therapies based on single and dual stimuli-responsive drug delivery systems (DDSs) that not only improved drug targeting in deeper sites of the tumor microenvironments, but also facilitated the antitumor drug release efficiency. Single and dual stimuli-responsive materials which are known for their lowest side effects can be categorized in 17 main groups which involve to internal and external stimuli anticancer drug carriers in proportion to microenvironments of targeted solid tumors. Development of such drug carriers can circumvent barriers in clinical trial studies based on their superior capabilities in penetrating into more inaccessible sites of the tumor tissues. In recent designs, key characteristics of these DDSs such as fast response to intracellular and extracellular factors, effective cytotoxicity with minimum side effect, efficient permeability, and rate and location of drug release have been discussed as core concerns of designing paradigms of these materials.

Role of Cancer Side Population Stem Cells in Ovarian Cancer Angiogenesis

Ovarian cancer is one of the most common gynecologic malignancies. Recurrence and metastasis often occur after treatment, and it has the highest mortality rate of all gynecological tumors. Cancer stem cells (CSCs) are a small population of cells with the ability of self-renewal, multidirectional differentiation, and infinite proliferation. They have been shown to play an important role in tumor growth, metastasis, drug resistance, and angiogenesis. Ovarian cancer side population (SP) cells, a type of CSC, have been shown to play roles in tumor formation, colony formation, xenograft tumor formation, ascites formation, and tumor metastasis. The rapid progression of tumor angiogenesis is necessary for tumor growth; however, many of the mechanisms driving this process are unclear as is the contribution of CSCs. The aim of this review was to document the current state of knowledge of the molecular mechanism of ovarian cancer stem cells (OCSCs) in regulating tumor angiogenesis.

Bevacizumab-Based Therapies in Malignant Tumors-Real-World Data on Effectiveness, Safety, and Cost

Overall, it is estimated that more than 3,500,000 patients have received Bevacizumab as part of systemic oncologic treatment. Bevacizumab and its biosimilars are currently marketed in over 130 countries. Given the wide usage of Bevacizumab in current oncological practice, it is very important to compare the "real-world" results to those obtained in controlled clinical trials. This study aims to describe the clinical experience of using Bevacizumab in a large cohort of cancer patients in "non-controlled real-world" conditions with regard to effectiveness, safety, and cost of therapy.

METHODS

For this purpose, we conducted an open, observational, retrospective study involving all patients treated for solid malignant tumors in the Bucharest Institute of Oncology with "Prof. Dr. Al. Trestioreanu" with Bevacizumab-based systemic therapy, between 2017 and 2021.

RESULTS

The study consisted of 657 treatment episodes in 625 patients (F/B = 1.62/1, with a median age of 57.6 years) which were treated for malignant tumors (majority colorectal, non-small cell lung, ovarian, and breast cancer). First-line treatment was administered in 229 patients, and the rest received Bevacizumab as second or subsequent lines of treatment. The overall response rate to Bevacizumab-based therapies was around 60-65% across all indication except for subsequent treatment lines in colorectal and ovarian cancers, where lower values were recorded (27.1%, and 31.5% respectively). Median PFS for the entire cohort was 8.2 months (95% CI 6.8-9.6), and the median OS was 13.2 months (95% CI 11.5-14.9). Usual bevacizumab-related toxicities were observed, including bleeding, hypertension, wound-healing complications, gastrointestinal perforation, other types of fistulas, septic complications, and thromboembolic events. Although the clinical benefits are undeniable, the addition of Bevacizumab to standard chemotherapy increased the overall treatment cost by 213%.

CONCLUSIONS

Bevacizumab remains a high-cost therapy, but it can add to clinical benefits (like overall survival, progression-free survival, and response rate) when used in conjunction with standard chemotherapy. Similar results as those presented in various controlled trials are observable even on unselected cohorts of patients in the uncontrolled conditions of "real-world" oncological practice. Off-label usage is encountered in clinical practice, and this aspect should be monitored given the potential adverse effects of the therapy.

Prostate-Specific Membrane Antigen Radioligand Therapy in Non-Prostate Cancers: Where Do We Stand?

INTRODUCTION

The term theragnostic refers to the combination of a predictive imaging biomarker with a therapeutic agent. The promising application of prostate-specific membrane antigen (PSMA)-based radiopharmaceuticals in the imaging and treatment of prostate cancer (PCa) patients opens the way to investigate a possible role of PSMA-based radiopharmaceuticals in cancers beyond the prostate. Therefore, the aim of this review was to evaluate the role of 177Lu-PSMA radioligand therapy (RLT) in malignancies other than prostate cancer by evaluating preclinical, clinical studies, and ongoing clinical trials.

METHODS

An extensive literature search was performed in three different databases using different combinations of the following terms: "Lu-PSMA", "177Lu-PSMA", "preclinical", "mouse", "salivary gland cancer", "breast cancer", "glioblastoma", "solid tumour", "renal cell carcinoma", "HCC", "thyroid", "salivary", "radioligand therapy", and "lutetium-177". The search had no beginning date limit and was updated to April 2024. Only articles written in English were included in this review.

RESULTS

A total of four preclinical studies were selected (breast cancer model n = 3/4). PSMA-RLT significantly reduced cell viability and had anti-angiogenic effects, especially under hypoxic conditions, which increase PSMA binding and uptake. Considering the clinical studies (n = 8), the complexity of evaluating PSMA-RLT in cancers other than prostate cancer was clearly revealed, since in most of the presented cases a sufficient tumour radiation dose was not achieved. However, encouraging results can be found in some types of diseases, such as thyroid cancer. Some clinical trials are still ongoing, and results from prospective larger cohorts of patients are awaited.

CONCLUSIONS

The need for larger patient cohorts and more RLT cycles administered underscores the need for further comprehensive studies. Given the very preliminary results of both preclinical and clinical studies, ongoing clinical trials in the near future may provide stronger evidence of both the safety and therapeutic efficacy of PSMA-RLT in malignancies other than prostate cancer.

Filter-exchange spectroscopy is sensitive to gradual cell membrane degradation

Transmembrane water permeability changes occur after initialization of necrosis and are a mechanism for early detection of cell death. Filter-exchange spectroscopy (FEXSY) is sensitive to transmembrane water permeability and enables its quantification by magnetic resonance via the apparent exchange rate (AXR). In this study, we investigate AXR changes during necrotic cell death. FEXSY measurements of yeast cells in different necrotic stages were performed and compared with established fluorescence cell death markers and pulsed gradient spin echo measurements. Furthermore, the influence of T2 relaxation on AXR was examined in a two-compartment system. The AXR of yeast cells increased slightly after incubation with 20% isopropanol, whereas it peaked sharply after incubation with 25% isopropanol. At this point, almost all the yeast cells were vital but showed compromised membranes. After incubation with 30% isopropanol, AXR measurements showed high variability, at a point corresponding to a majority of the yeast cells being in late-stage necrosis with disrupted cell membranes. Simulations revealed that, for FEXSY measurements in a two-compartment system, a long filter echo time (TEf), compared with the T2 of the slow-diffusing compartment, filters out a fraction of the slow-diffusing compartment signal and leads to overestimation of apparent diffusion coefficient (ADC) and underestimation of AXR. Our results demonstrate that AXR is sensitive to gradual permeabilization of the cell membrane of living cells in different permeabilization stages without exogenous contrast agents. AXR measurements were sensitive to permeability changes induced by relatively low concentrations of isopropanol, at levels for which no measurable effect was detectable by ADC measurements. TEf may act as a signal filter that affects the estimated AXR value of a system consisting of a variety of local diffusivities and a range of T2 that includes T2 values shorter or comparable with the TEf.

Prognostic significance and value of further classification of lymphovascular invasion in invasive breast cancer: a retrospective observational study

PURPOSE

To investigate the prognostic significance of lymphovascular invasion in invasive breast cancer and the value of using specific vascular endothelial markers to further classify lymphovascular invasion.

METHODS

We collected 2124 patients with invasive breast cancer who were hospitalized at the First Hospital of Dalian Medical University from 2012 to 2020. Statistical methods were used to investigate the relationship between lymphovascular invasion and clinicopathological characteristics of breast cancer, and the correlation between lymphovascular invasion on overall survival (OS) and disease-free survival (DFS) of various categories of breast cancers. Immunohistochemical staining of breast cancer samples containing lymphovascular invasion using specific vascular endothelial markers D2-40 and CD34 was used to classify lymphovascular invasion and to investigate the relationship between lymphovascular invasion and breast cancer progression.

RESULTS

There was a high correlation between lymphovascular invasion and T stage, N stage and nerve invasion. Survival analyses showed that patients with lymphovascular invasion, especially luminal B, triple-negative, and Her-2 overexpression breast cancer patients, had poorer OS and DFS prognosis, and that lymphovascular invasion was an independent prognostic factor affecting OS and DFS in breast cancer. The immunohistochemical staining results showed that positive D2-40 staining of lymphovascular invasion was linked to the N stage and localized recurrence of breast cancer.

CONCLUSION

Lymphovascular invasion is associated with aggressive clinicopathological features and is an independent poor prognostic factor in invasive breast cancer. Breast cancer localized recurrence rate and lymph node metastases are influenced by lymphatic vessel invasion. Immunohistochemical techniques should be added to the routine diagnosis of lymphovascular invasion.

Chondroitin sulfate-based universal nanoparticle delivers angiogenic inhibitor and paclitaxel to exhibit a combination of chemotherapy and anti-angiogenic therapy

Blocking the tumor nutrient supply through angiogenic inhibitors is an effective treatment approach for malignant tumors. However, using angiogenic inhibitors alone may not be enough to achieve a significant tumor response. Therefore, we recently designed a universal drug delivery system combining chemotherapy and anti-angiogenic therapy to target tumor cells while minimizing drug-related side effects. This system (termed as PCCE) is composed of biomaterial chondroitin sulfate (CS), the anti-angiogenic peptide ES2, and paclitaxel (PTX), which collectively enhance antitumor properties. Interestingly, the PCCE system is conferred exceptional cell membrane permeability due to inherent characteristics of CS, including CD44 receptor-mediated endocytosis. The PCCE could respond to the acidic and high glutathione conditions, thereby releasing PTX and ES2. PCCE could effectively inhibit the proliferation, migration, and invasion of tumor cells and cause apoptosis, while PCCE can affect the endothelial cells tube formation and exert anti-angiogenic function. Consistently, more potent in vivo antitumor efficacy and non-toxic sides were demonstrated in B16F10 xenograft mouse models. PCCE can achieve excellent antitumor activity via modulating angiogenic and apoptosis-related factors. In summary, we have successfully developed an intelligent and responsive CS-based nanocarrier known as PCCE for delivering various antitumor drugs, offering a promising strategy for treating malignant tumors.

An arresten-derived anti-angiogenic peptide triggers apoptotic cell death in endothelial cells

BACKGROUND

In recent years, anti-angiogenic peptides have received considerable attention as candidates for cancer treatment. Arresten is an angiogenesis inhibitor that cleaves from the α1 chain of type IV collagen and stimulates apoptosis in endothelial cells. We have recently indicated that a peptide corresponding to the amino acid 78 to 86 of arresten, so-called Ars, prevented the migration and tube formation of HUVECs and the colon carcinoma growth in mice significantly. The current study aimed to determine whether induction of apoptotic cell death in endothelial cells is one of the biochemical mechanisms of this anti-angiogenic peptide.

METHODS AND RESULTS

This hypothesis was assessed using the MTT assay, cell cycle analysis, Annexin V-FITC/PI staining, BCL2, CASP8, CASP9, p53, and CDKN2A gene expression studies as well as evaluating apoptosis in tumor tissues by TUNEL assay. Results demonstrated that 40 µM of Ars significantly stimulated 46.2% of early and late apoptosis in HUVECs compared to 13.6% in the untreated cells and did not significantly alter the cell cycle distribution. Moreover, BCL2 and CASP8 were down-regulated, while CASP9 and p53 were up-regulated in endothelial cells. CDKN2A gene expression, the regulator of G1 cell cycle arrest, was not significantly altered.

CONCLUSIONS

It might be suggested that Ars induced apoptosis in endothelial cells through the mitochondrial pathway and had no effect on the cell cycle. Besides, Ars induced apoptosis significantly in vivo. However, further studies are required to confirm the detailed molecular mechanism of Ars, this peptide has the potential to be optimized for clinical translations.

Exploiting the immune system in hepatic tumor targeting: Unleashing the potential of drugs, natural products, and nanoparticles

Hepatic tumors present a formidable challenge in cancer therapeutics, necessitating the exploration of novel treatment strategies. In recent years, targeting the immune system has attracted interest to augment existing therapeutic efficacy. The immune system in hepatic tumors includes numerous cells with diverse actions. CD8+ T lymphocytes, T helper 1 (Th1) CD4+ T lymphocytes, alternative M1 macrophages, and natural killer (NK) cells provide the antitumor immunity. However, Foxp3+ regulatory CD4+ T cells (Tregs), M2-like tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs) are the key immune inhibitor cells. Tumor stroma can also affect these interactions. Targeting these cells and their secreted molecules is intriguing for eliminating malignant cells. The current review provides a synopsis of the immune system components involved in hepatic tumor expansion and highlights the molecular and cellular pathways that can be targeted for therapeutic intervention. It also overviews the diverse range of drugs, natural products, immunotherapy drugs, and nanoparticles that have been investigated to manipulate immune responses and bolster antitumor immunity. The review also addresses the potential advantages and challenges associated with these approaches.

Novel multi-target angiogenesis inhibitors as potential anticancer agents: Design, synthesis and preliminary activity evaluation

Based on the crucial role of histone deacetylase (HDAC) and receptor tyrosine kinase in angiogenesis, in situ assembly, skeletal transition, molecular hybridization, and pharmacophore fusion were employed to yield seventy-six multi-target angiogenesis inhibitors. Biological evaluation indicated that most of the compounds exhibited potent proliferation inhibitory activity on MCF-7 cells, with the TH series having the highest inhibitory activity on MCF-7 cells. In addition, the IC50 values of TA11 and TH3 against HT-29 cellswere 0.078 μmol/L and 0.068 μmol/L, respectively. The cytotoxicity evaluation indicated that TC9, TA11, TM4, and TH3 displayed good safety against HEK293T cells. TH2 and TH3 could induce apoptosis of MCF-7 cells. Molecular modeling and ADMET prediction results indicated that most of target compounds showed promising medicinal properties, which was consistent with the experimental results. Our findings provided new lead compounds for the structural optimization of multi-target angiogenesis inhibitors.

Molecular targeted therapies for cutaneous squamous cell carcinoma: recent developments and clinical implications

Cutaneous Squamous Cell Carcinoma (cSCC) is a common and potentially fatal type of skin cancer that poses a significant threat to public health and has a high prevalence rate. Exposure to ultraviolet radiation on the skin surface increases the risk of cSCC, especially in those with genetic syndromes like xerodermapigmentosum and epidermolysis bullosa. Therefore, understanding the molecular pathogenesis of cSCC is critical for developing personalized treatment approaches that are effective in cSCC. This article provides a comprehensive overview of current knowledge of cSCC pathogenesis, emphasizing dysregulated signaling pathways and the significance of molecular profiling. Several limitations and challenges associated with conventional therapies, however, are identified, stressing the need for novel therapeutic strategies. The article further discusses molecular targets and therapeutic approaches, i.e., epidermal growth factor receptor inhibitors, hedgehog pathway inhibitors, and PI3K/AKT/mTOR pathway inhibitors, as well as emerging molecular targets and therapeutic agents. The manuscript explores resistance mechanisms to molecularly targeted therapies and proposes methods to overcome them, including combination strategies, rational design, and optimization. The clinical implications and patient outcomes of molecular-targeted treatments are assessed, including response rates and survival outcomes. The management of adverse events and toxicities in molecular-targeted therapies is crucial and requires careful monitoring and control. The paper further discusses future directions for therapeutic advancement and research in this area, as well as the difficulties and constraints associated with conventional therapies.

Therapeutic effects and underlying mechanism of poly (L-glutamic acid)-g-methoxy poly (ethylene glycol)/combretastatin A4/BLZ945 nanoparticles on Renca renal carcinoma

Introduction: The prognosis of advanced renal carcinoma is not ideal, necessitating the exploration of novel treatment strategies. Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/Combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) possess the dual capability of CA4 (targeting blood vessels to induce tumor necrosis) and BLZ945 (inducing M2 macrophage apoptosis), thereby inhibiting tumor growth. Methods: Here, the therapeutic effects and underlying mechanism was explored by CCK-8 cytotoxicity experiment, transwell cell invasion and migration experiment, H&E, western blot analysis, immunohistochemistry, flow cytometry, and other techniques. Results: These results demonstrated that CB-NPs could inhibit the growth of Renca cells and subcutaneous tumors in mice, with an impressive tumor inhibition rate of 88.0%. Results suggested that CB-NPs can induce necrosis in renal carcinoma cells and tissues, downregulate VEGFA expression, promote renal carcinoma cell apoptosis, and reduce the polarization of M2 macrophages. Discussion: These findings offer innovative perspectives for the treatment of advanced renal carcinoma.

Hierarchical-unlocking virus-esque NanoCRISPR precisely disrupts autocrine and paracrine pathway of VEGF for tumor inhibition and antiangiogenesis

Vascular endothelial growth factor (VEGF) not only serves as an autocrine survival factor for tumor cells themselves, but also stimulates angiogenesis by paracrine pathway. Strategies targeting VEGF holds tremendous potential for tumor therapy, however, agents targeting VEGF are limited by intolerable side effects, together with incomplete and temporary blocking of VEGF, resulting in unsatisfactory and unsustained therapeutic outcomes. Herein, hierarchical-unlocking virus-esque NanoCRISPR (HUNGER) is constructed for complete, permanent and efficient intracellular disruption of autocrine and paracrine pathway of VEGF, thereby eliciting notable tumor inhibition and antiangiogenesis. After intravenous administration, HUNGER exhibits prolonged blood circulation and hyaluronic acid-CD44 mediated tumor-targeting capability. Subsequently, when matrix metalloproteinase-2 is overexpressed in the tumor microenvironment, the PEG layer will be removed. The cell-penetrating peptide R8 endows HUNGER deep tumor penetration and specific cellular uptake. Upon cellular internalization, HUNGER undergoes hyaluronidase-triggered deshielding in lysosome, lysosomal escape is realized swiftly, and then the loaded CRISPR/Cas9 plasmid (>8 kb) is transported to nucleus efficiently. Consequentially, complete, permanent and efficient intracellular disruption of autocrine and paracrine pathway of VEGF ensures inhibition of angiogenesis and tumor growth with inappreciable toxicity. Overall, this work opens a brand-new avenue for anti-VEGF therapy and presents a feasible strategy for in vivo delivery of CRISPR/Cas9 system.

An In Vivo Dual-Observation Method to Monitor Tumor Mass and Tumor-Surface Blood Vessels for Developing Anti-Angiogenesis Agents against Submillimeter Tumors

Managing metastasis at the early stage and detecting and treating submillimeter tumors at early metastasis are crucial for improving cancer prognosis. Angiogenesis is a critical target for developing drugs to detect and inhibit submillimeter tumor growth; however, drug development remains challenging because there are no suitable models for observing the submillimeter tumor mass and the surrounding blood vessels in vivo. We have established a xenograft subcutaneous submillimeter tumor mouse model with HT-29-RFP by transplanting a single spheroid grown on radiation-crosslinked gelatin hydrogel microwells. Here, we developed an in vivo dual-observation method to observe the submillimeter tumor mass and tumor-surface blood vessels using this model. RFP was detected to observe the tumor mass, and a fluorescent angiography agent FITC-dextran was administered to observe blood vessels via stereoscopic fluorescence microscopy. The anti-angiogenesis agent regorafenib was used to confirm the usefulness of this method. This method effectively detected the submillimeter tumor mass and tumor-surface blood vessels in vivo. Regorafenib treatment revealed tumor growth inhibition and angiogenesis downregulation with reduced vascular extremities, segments, and meshes. Further, we confirmed that tumor-surface blood vessel areas monitored using in vivo dual-observation correlated with intratumoral blood vessel areas observed via fluorescence microscopy with frozen sections. In conclusion, this method would be useful in developing anti-angiogenesis agents against submillimeter tumors.

Exploring the pharmacological versatility of ficus carica: Modulating classical immunometabolism and beyond

The burden of metabolic disorders is alarmingly increasing globally. On the other hand, sustainability is the key project of the 21st century. Natural products offer a coherent option for the complementary management of both these challenges. Ficus carica (FC), commonly known as the fig fruit, has an experimentally proven potency for the modulation of cell cycle, immunity, inflammation, metabolism, and oxidative stress. Here, we review the potential of FC-derived products (FCDP) in slowing down the progression of cancers, acute/chronic inflammation-related conditions, infections, metabolic disorders, toxicities, neurological and neuromuscular diseases, gastrointestinal disorders, vascular diseases, and skin-stressing conditions, as well as, in boosting normal healthy functions of the endocrine, immune, metabolic, and nervous systems. It reveals a variety of cellular and molecular targets for FCDP: cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-18, IFN-γ), chemokines (CCL2), other inflammatory mediators (CRP, PGE2), immune receptors (TLR-2, TLR-4, FcεRI), oxidative stress-related markers (SOD, GSH, MDA, GPx, catalase, ROS, NO, protein carbonyls), kinases (MAPKs, hexokinase, G6Pase, FBPase, PEPCK, Akt, AMPK, GSK3, CDKs), other enzymes (COX-2, iNOS, MMPs, caspases), growth factors/receptors (VEGF, EGFR), hormones (DHEAS, prolactin, GnRH, FSH, LH, estradiol, DHT, insulin), cell death-related markers (Bcl-2, Bax, Bak, FasL, gasdermins, cytochrome C), glucose transporter protein (Glut4), and transcription factors (NF-κB, HNF-4α, Foxo, PGC-1α, PPAR-γ, C/EBP-α, CREB, NFATC1, STAT3). FCDP cause both activation and inhibition of AMPK, MAPK, and NF-κB signaling to confer condition-specific advantages. Such a broad-range activity might be attributed to different mechanisms of action of FCDP in modulating functions within the classical immunometabolic system, but also beyond.

A novel small molecule, CU05-1189, targeting the pleckstrin homology domain of PDK1 suppresses VEGF-mediated angiogenesis and tumor growth by blocking the Akt signaling pathway

Inhibition of angiogenesis is considered a promising therapeutic approach for cancer treatment. Our previous genetic research showed that the use of a cell-penetrating peptide to inhibit the pleckstrin homology (PH) domain of 3-phosphoinositide-dependent kinase 1 (PDK1) was a viable approach to suppress pathological angiogenesis. Herein, we synthesized and characterized a novel small molecule, CU05-1189, based on our prior study and present evidence for the first time that this compound possesses antiangiogenic properties both in vitro and in vivo. The computational analysis showed that CU05-1189 can interact with the PH domain of PDK1, and it significantly inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration, invasion, and tube formation in human umbilical vein endothelial cells without apparent toxicity. Western blot analysis revealed that the Akt signaling pathway was specifically inhibited by CU05-1189 upon VEGF stimulation, without affecting other VEGF receptor 2 downstream molecules or cytosolic substrates of PDK1, by preventing translocation of PDK1 to the plasma membrane. We also found that CU05-1189 suppressed VEGF-mediated vascular network formation in a Matrigel plug assay. More importantly, CU05-1189 had a good pharmacokinetic profile with a bioavailability of 68%. These results led to the oral administration of CU05-1189, which resulted in reduced tumor microvessel density and growth in a xenograft mouse model. Taken together, our data suggest that CU05-1189 may have great potential and be a promising lead as a novel antiangiogenic agent for cancer treatment.

Development of a Highly In Vivo Efficacious Dual Antitumor and Antiangiogenic Organoiridium Complex as a Potential Anti-Lung Cancer Agent

While the phenomenal clinical success of blockbuster platinum (Pt) drugs is highly encouraging, the inherent and acquired resistance and dose-limiting side effects severely limit their clinical application. To find a better alternative with translational potential, we synthesized a library of six organo-IrIII half-sandwich [(η5-CpX)Ir(N∧N)Cl]+-type complexes. In vitro screening identified two lead candidates [(η5-CpXPh)Ir(Ph2Phen)Cl]+ (5, CpXPh = tetramethyl-phenyl-cyclopentadienyl and Ph2Phen = 4,7-diphenyl-1,10-phenanthroline) and [(η5-CpXBiPh)Ir(Ph2Phen)Cl]+ (6, CpXBiPh = tetramethyl-biphenyl-cyclopentadienyl) with nanomolar IC50 values. Both 5 and 6 efficiently overcame Pt resistance and presented excellent cancer cell selectivity in vitro. Potent antiangiogenic properties of 6 were demonstrated in the zebrafish model. Satisfyingly, 6 and its nanoliposome Lipo-6 presented considerably higher in vivo antitumor efficacy as compared to cisplatin, as well as earlier reported IrIII half-sandwich complexes in mice bearing the A549 non-small lung cancer xenograft. In particular, complex 6 is the first example of this class that exerted dual in vivo antiangiogenic and antitumor properties.

AATF inhibition exerts antiangiogenic effects against human hepatocellular carcinoma

Background and aims

Angiogenesis is a key factor in the growth and metastasis of hepatic tumors and thus a potential therapeutic target in hepatocellular carcinoma (HCC). In this study, we aim to identify the key role of apoptosis antagonizing transcription factor (AATF) in tumor angiogenesis and its underlying mechanisms in HCC.

Methods

HCC tissues were analyzed for AATF expression by qRT-PCR and immunohistochemistry. Stable clones of control and AATF knockdown (KD) were established in human HCC cells. The effect of AATF inhibition on the angiogenic processes was determined by proliferation, invasion, migration, chick chorioallantoic membrane (CAM) assay, zymography, and immunoblotting techniques.

Results

We identified high levels of AATF in human HCC tissues compared to adjacent normal liver tissues, and the expression was found to be correlated with the stages and tumor grades of HCC. Inhibiting AATF in QGY-7703 cells resulted in higher levels of pigment epithelium-derived factor (PEDF) than controls due to decreased matric metalloproteinase activity. Conditioned media from AATF KD cells inhibited the proliferation, migration, and invasion of human umbilical vein endothelial cells as well as the vascularization of the chick chorioallantoic membrane. Furthermore, the VEGF-mediated downstream signaling pathway responsible for endothelial cell survival and vascular permeability, cell proliferation, and migration favoring angiogenesis was suppressed by AATF inhibition. Notably, PEDF inhibition effectively reversed the anti-angiogenic effect of AATF KD.

Conclusion

Our study reports the first evidence that the therapeutic strategy based on the inhibition of AATF to disrupt tumor angiogenesis may serve as a promising approach for HCC treatment.

Inhibiting Angiogenesis by Anti-Cancer Saponins: From Phytochemistry to Cellular Signaling Pathways

Saponins are one of the broadest classes of high-molecular-weight natural compounds, consisting mainly of a non-polar moiety with 27 to 30 carbons and a polar moiety containing sugars attached to the sapogenin structure. Saponins are found in more than 100 plant families as well as found in marine organisms. Saponins have several therapeutic effects, including their administration in the treatment of various cancers. These compounds also reveal noteworthy anti-angiogenesis effects as one of the critical strategies for inhibiting cancer growth and metastasis. In this study, a comprehensive review is performed on electronic databases, including PubMed, Scopus, ScienceDirect, and ProQuest. Accordingly, the structural characteristics of triterpenoid/steroid saponins and their anti-cancer effects were highlighted, focusing on their anti-angiogenic effects and related mechanisms. Consequently, the anti-angiogenic effects of saponins, inhibiting the expression of genes related to vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1-α (HIF-1α) are two main anti-angiogenic mechanisms of triterpenoid and steroidal saponins. The inhibition of inflammatory signaling pathways that stimulate angiogenesis, such as pro-inflammatory cytokines, mitogen-activated protein kinase (MAPKs), and phosphoinositide 3-kinases/protein kinase B (PI3K/Akt), are other anti-angiogenic mechanisms of saponins. Furthermore, the anti-angiogenic and anti-cancer activity of saponins was closely related to the binding site of the sugar moiety, the type and number of their monosaccharide units, as well as the presence of some functional groups in their aglycone structure. Therefore, saponins are suitable candidates for cancer treatment by inhibiting angiogenesis, for which extensive pre-clinical and comprehensive clinical trial studies are recommended.

Gold nanoparticles as antiangiogenic and antimetastatic agents

Angiogenesis and metastasis are two interdependent cancer hallmarks, the latter of which is the key cause of treatment failure. Thus, establishing effective antiangiogenesis/antimetastasis agents is the final frontier in cancer research. Gold nanoparticles (GNPs) may provide disruptive advancements in this regard due to their intrinsic physical and physiological features. Here, we comprehensively discuss recent potential therapeutical strategies to treat angiogenesis and metastasis and present a critical review on the state-of-the-art in vitro and in vivo evaluations of the antiangiogenic/antimetastatic activity of GNPs. Finally, we provide perspectives on the contribution of GNPs to the advancement of cancer management.

Design, Synthesis, Biological Evaluation, and Preliminary Mechanistic Study of a Novel Mitochondrial-Targeted Xanthone

α-Mangostin, a natural xanthone, was found to have anticancer effects, but these effects are not sufficient to be effective. To increase anticancer potential and selectivity, a triphenylphosphonium cation moiety (TPP) was introduced to α-mangostin to specifically target cancer cell mitochondria. Compared to the parent compound, the cytotoxicity of the synthesized compound 1b increased by one order of magnitude. Mechanistic analysis revealed that the anti-tumor effects were involved in the mitochondrial apoptotic pathway by prompting apoptosis and arresting the cell cycle at the G0/G1 phase, increasing the production of reactive oxygen species (ROS), and reducing mitochondrial membrane potential (Δψ_m). More notably, the antitumor activity of compound 1b was further confirmed by zebrafish models, which remarkably inhibited cancer cell proliferation and migration, as well as zebrafish angiogenesis. Taken together, our results for the first time indicated that TPP-linked 1b could lead to the development of new mitochondrion-targeting antitumor agents.

Unraveling the Synergy between Atezolizumab and Bevacizumab for the Treatment of Hepatocellular Carcinoma

Tyrosine kinase inhibitors (TKIs) with antiangiogenic properties, such as sorafenib, have been the standard choice to systemically treat hepatocellular carcinoma for over a decade. More recently, encouraging results were obtained using immune checkpoint inhibitors, although head-to-head comparisons with sorafenib in phase 3 trials could not demonstrate superiority in terms of overall survival. The IMbrave150 was a breakthrough study that resulted in atezolizumab/bevacizumab, a combination of an antiangiogenic and an immune checkpoint inhibitor, as a new standard of care for advanced HCC. This review discusses the mode of action, clinical efficacy, and biomarker research for both drug classes and for the combination therapy. Moreover, the synergy between atezolizumab and bevacizumab is highlighted, unraveling pathophysiological mechanisms underlying an enhanced anticancer immunity by changing the immunosuppressed to a more immunoreactive tumor microenvironment (TME). This is achieved by upregulation of antigen presentation, upregulation of T-cell proliferation, trafficking and infiltration, impairing recruitment, and proliferation of immunosuppressive cells in the TME. However, more insights are needed to identify biomarkers of response that may improve patient selection and outcome.

Involvement of angiogenesis in cancer-associated acinar-to-ductal metaplasia lesion of pancreatic cancer invasive front

PURPOSE

This study aimed to demonstrate the involvement of angiogenesis in cancer-associated acinar-to-ductal metaplasia (CA-ADM) lesion of invasive front pancreatic ductal adenocarcinoma (PDAC) and investigate the possible mechanism.

METHODS

Tissue samples from 128 patients with PDAC and 36 LSL-Kras^G12D/+; LSL-Trp53^R172H/+; Pdx-1-Cre mice were analyzed. Immunohistochemical assay was performed using HE, anti-CK19 and anti-amylase to confirm the presence of CA-ADM lesions, using anti-CD34 and anti-CD31 to measure microvessel density (MVD), and using anti-CD68, anti-CD163, anti-iNOS, or anti-MMP9 to evaluate the immune microenvironment. We performed multiplex immunohistochemical assay to detect the co-expression of MMP9 and CD68 on macrophage. We examined clinical outcomes and other clinicopathological factors to determine the significance of high-level MVD of CA-ADM on survival and liver metastasis. We performed tube formation assay to evaluate the effect of macrophage on angiogenic capacity in vitro.

RESULTS

Angiogenesis was significantly abundant in CA-ADM lesions compared with that in PDAC lesions in human and mouse tissues. High-level MVD in CA-ADM lesions was an independent predictor of poor prognosis (P = 0.0047) and the recurrence of liver metastasis (P = 0.0027). More CD68-positive and CD163-positive macrophages were detected in CA-ADM lesions than in PDAC. The percentage of CD68-positive macrophages was positively correlated with MVD in CA-ADM lesions. Multiplex-immunostaining revealed that MMP9 was expressed in CD68-positive macrophages of CA-ADM lesions. In CA-ADM lesions, the percentage of macrophages was positively correlated with MMP9 expression, which positively correlated with microvessel density.

CONCLUSION

CA-ADM related angiogenesis is a promising predictive marker for poor prognosis of PDAC and may provide an attractive therapeutic target for PDAC.

Potent Ruthenium-Ferrocene Bimetallic Antitumor Antiangiogenic Agent That Circumvents Platinum Resistance: From Synthesis and Mechanistic Studies to In Vivo Evaluation in Zebrafish

Emergence of resistance in cancer cells and dose-limiting side effects severely limit the widespread use of platinum (Pt) anticancer drugs. Multi-action hybrid anticancer agents that are constructed by merging two or more pharmacophores offer the prospect of circumventing issues of Pt drugs. Herein, we report the design, synthesis, and in-depth biological evaluation of a ruthenium-ferrocene (Ru-Fc) bimetallic agent [(η6-p-cymene)Ru(1,1,1-trifluoro-4-oxo-4-ferrocenyl-but-2-en-2-olate)Cl] and its five analogues. Along with aquation/anation chemistry, we evaluated the in vitro antitumor potency, Pt cross-resistance profile, and in vivo antiangiogenic properties. A structure activity analysis was performed to understand the impact of Fc, CF3, and p-cymene groups on the anticancer potency of the Ru-Fc hybrid. Finally, in addition to assessing cellular uptake and intracellular distribution, we demonstrated that the Ru-Fc hybrid binds to nucleophilic biomolecules and produces reactive oxygen species, which causes mitochondrial dysfunction and induces ER stress, leading to poly(ADP-ribose) polymerase-mediated necroptotic cell death.

Resistance to Antiangiogenic Therapy in Hepatocellular Carcinoma: From Molecular Mechanisms to Clinical Impact

Antiangiogenic drugs were the only mainstay of advanced hepatocellular carcinoma (HCC) treatment from 2007 to 2017. However, primary or secondary resistance hampered their efficacy. Primary resistance could be due to different molecular and/or genetic characteristics of HCC and their knowledge would clarify the optimal treatment approach in each patient. Several molecular mechanisms responsible for secondary resistance have been discovered over the last few years; they represent potential targets for new specific drugs. In this light, the advent of checkpoint inhibitors (ICIs) has been a new opportunity; however, their use has highlighted other issues: the vascular normalization compared to a vessel pruning to promote the delivery of an active cancer immunotherapy and the development of resistance to immunotherapy which leads to a better selection of patients as candidates for ICIs. Nevertheless, the combination of antiangiogenic therapy plus ICIs represents an intriguing approach with high potential to improve the survival of these patients. Waiting for results from ongoing clinical trials, this review depicts the current knowledge about the resistance to antiangiogenic drugs in HCC. It could also provide updated information to clinicians focusing on the most effective combinations or sequential approaches in this regard, based on molecular mechanisms.

The prognostic value and immunological role of angiogenesis-related patterns in colon adenocarcinoma

Colon adenocarcinoma (COAD) is a malignant tumor with a high mortality rate. Angiogenesis plays a key role in the development and progression of cancer. However, in COAD, studies between angiogenesis and prognosis, immune cell infiltration, and personalized treatment guidance are currently lacking. In the present study, we comprehensively assessed 35 angiogenesis-related genes (ARG) and identified key ARGs affecting OS in COAD patients. The ARG Prognostic Index (ARGPI) was constructed based on a univariate Cox regression model and its prognostic value was evaluated in TCGA-COAD, GSE39582, GSE161158 and TRSJTUSM Cohort. We constructed ARGPI as an independent risk factor for OS in COAD patients and combined with clinical parameters to further construct an ARGPI-based nomogram, which showed a strong ability to predict overall survival in COAD patients. High ARGPI is associated with cancer-related and immune-related biological processes and signaling pathways; high TP53 mutation rate; high infiltration of MSC, pericytes, and stromal cells; and more CMS4 subtype. And low ARGPI benefited more from immune checkpoint inhibitor treatment. In addition, we also predicted the sensitivity of different ARGPI groups to common chemotherapeutic and targeted agents. In conclusion, this study constructed an ARGPI based on ARG, which robustly predicted the OS of COAD patients and provided a possible personalized treatment regime for COAD patients.

The efficacy of oxaliplatin, surufatinib, and camrelizumab on neuroendocrine carcinoma: a case report and literature review

Background

Extra-pulmonary neuroendocrine carcinomas (EP-NECs) are rare, accounting for ~1/100,000 of NECs, aggressive neoplasms and poor prognosis. Sometimes, a non-neuroendocrine component is also accompanying these EP-NECs. Curative surgery is suggested for early stage patients while system chemotherapy and locoregional radiotherapy are considered for advanced inoperable disease. Nonetheless, there was lack of standard second-line treatment strategy. Herein, we report a case of NEC involving a large cell neuroendocrine carcinoma (LCNEC) and adenocarcinoma of the gallbladder treated with a surufatinib-containing regimen in the second-line treatment setting and establish the efficacy of this regimen in the treatment of EP-NECs.

Case Description

A 58-year-old male presented with symptoms such as distension in the upper right abdomen and a palpable mass. The abdominal magnetic resonance imaging (MRI) scan showed a giant soft tissue mass in the left lobe of the liver, and liver biopsy suggested LCNEC with a non-neuroendocrine (NNE) component. Based on the available literature, a first-line therapy of oxaliplatin + gemcitabine + camrelizumab + apatinib was started initially; however, there was rapid tumor progression. Thus, a second line of treatment was started, where apatinib was replaced with surufatinib, which was given along with oxaliplatin and camrelizumab and continued for seven complete cycles. The patient was re-examined with MRI, which showed a significant decrease in tumor size. And a partial response was achieved. Main adverse events included hand and foot numbness, hypertension, proteinuria, hematuria, and hyperthyroidism. The patient underwent surgery after the second line of treatment and the post-operative pathology report revealed the presence of LCNEC and adenocarcinoma of the gallbladder. Two months later, re-examination result showed no tumor recurrence.

Conclusions

As yet, the criteria strategy for unresectable EP-NECs to improve survival outcomes is scarce. EP-NECs are badly in need of effective second-line therapy to carry out survival benefits after resistance to first-line regimen. The case report demonstrated that a surufatinib-containing regimen including oxaliplatin and camrelizumab could be an effective treatment strategy for the second-line treatment of EP-NECs. Furthermore, this strategy is well tolerated and treatment-related toxicity are manageable. More clinical trials are warranted to further confirm the efficacy.

Angiogenesis and Its Targeting in Glioblastoma with Focus on Clinical Approaches

Angiogenesis is a characteristic of glioblastoma (GBM), the most fatal and therapeutic-resistant brain tumor. Highly expressed angiogenic cytokines and proliferated microvascular system made anti-angiogenesis treatments a thoroughly plausible approach for GBM treatment. Many trials have proved to be not only as a safe but also as an effective approach in GBM retardation in a certain time window as seen in radiographic response rates; however, they have failed to implement significant improvements in clinical manifestation whether alone or in combination with radio/chemotherapy. Bevasizumab, an anti-vascular endothelial growth factor-A (VEGF-A) antibody, is the only agent that exerts meaningful clinical influence by improving progression-free survival (PFS) and partially alleviate clinical symptoms, nevertheless, it could not prolong the overall survival (OS) in patients with GBM. The data generated from phase II trials clearly revealed a correlation between elevated reperfusion, subsequent to vascular normalization induction, and improved clinical outcomes which explicitly indicates anti-angiogenesis treatments are beneficial. In order to prolong these initial benefits observed in a certain period of time after anti-angiogenesis targeting, some aspects of the therapy should be tackled: recognition of other bypass angiogenesis pathways activated following antiangiogenesis therapy, identification of probable pathways that induce insensitivity to shortage of blood supply, and classifying the patients by mapping their GBM-related gene profile as biomarkers to predict their responsiveness to therapy. Herein, the molecular basis of brain vasculature development in normal and tumoral conditions is briefly discussed and it is explained how "vascular normalization" concept opened a window to a better comprehension of some adverse effects observed in anti-angiogenesis therapy in clinical condition. Then, the most targeted angiogenesis pathways focused on ligand/receptor interactions in GBM clinical trials are reviewed. Lastly, different targeting strategies applied in anti-angiogenesis treatment are discussed.

Usnic Acid Isolated from Usnea antarctica (Du Rietz) Reduced In Vitro Angiogenesis in VEGF- and bFGF-Stimulated HUVECs and Ex Ovo in Quail Chorioallantoic Membrane (CAM) Assay

Simple Summary

Anti-angiogenic therapy, a promising strategy against cancer progression, is limited by drug resistance. Natural plants, such as secondary metabolites of lichens, may represent an appropriate strategy to increase the effectiveness of conventional therapies and overcome resistance to anti-angiogenic therapy if combined with existing chemotherapy. Accordingly, our study was designed to determine the potential anti-angiogenic effect of usnic acid, a secondary metabolite of lichens, on VEGF- and bFGF-stimulated HUVECs as well as in quail chorioallantoic membrane assays, which were supplemented by histological sections of CAM-affected layers.

Abstract

Natural products include a diverse set of compounds of drug discovery that are currently being actively used to target tumor angiogenesis. In the present study, we evaluated the anti-angiogenic activities of secondary metabolite usnic acid isolated from Usena antarctica. We investigated the in vitro effects on proliferation, migration, and tube formation of VEGF- and bFGF-stimulated HUVECs. Ex ovo anti-angiogenic activity was evaluated using the CAM assay. Our findings demonstrated that usnic acid in the concentration of 33.57 µM inhibited VEGF (25 ng/mL) and bFGF (30 ng/mL)-induced HUVECs proliferation, migration, and tube formation. The ex ovo CAM model was used to confirm the results obtained from in vitro studies. VEGF- and bFGF-induced vessel formation was inhibited by usnic acid after 72 h in over 2-fold higher concentrations compared to in vitro. Subsequently, histological sections of affected chorioallantoic membranes were stained with hematoxylin–eosin and alcian blue to determine the number and diameter of vessels as well as the thickness of the individual CAM layers (ectoderm, mesoderm, endoderm). Usnic acid was able to suppress the formation of VEGF- and bFGF-induced vessels with a diameter of less than 100 μm, which was demonstrated by the reduction of mesoderm thickness as well.

Recent advances in nano-drug delivery systems for synergistic antitumor immunotherapy

Immunotherapy has demonstrated great clinical success in the field of oncology in comparison with conventional cancer therapy. However, cancer immunotherapy still encounters major challenges that limit its efficacy against different types of cancers and the patients show minimal immune response to the immunotherapy. To overcome these limitations, combinatorial approaches with other therapeutics have been applied in the clinic. Simultaneously, nano-drug delivery system has played an important role in increasing the antitumor efficacy of various treatments and has been increasingly utilized for synergistic immunotherapy to further enhance the immunogenicity of the tumors. Specifically, they can promote the infiltration of immune cells within the tumors and create an environment that is more sensitive to immunotherapy, particularly in solid tumors, by accelerating tumor accumulation and permeability. Herein, this progress report provides a brief overview of the development of nano-drug delivery systems, classification of combinatory cancer immunotherapy and recent progress in tumor immune synergistic therapy in the application of nano-drug delivery systems.

Hemimycale Arabica Induced Non-Cytotoxic Anti-Migratory Activity in Hepatocellular Carcinoma In Vitro

OBJECTIVE

In this work, we represented new non-cytotoxic treatments to avoid serious side effects of current used cytotoxic anticancer drugs. These treatments can compensate in finding convenient treatment for each individual case using a single agent from marine sponge Hemimycale arabica.

METHODS

The ethanol extract was partitioned by cold sequential liquid-liquid extraction to afford petroleum ether, diethyl ether, dichloromethane and ethyl acetate fractions. Chemical composition of H. arabica was performed by gas-liquid chromatography and gas chromatography-mass spectroscopy. Anticancer activity was evaluated by means of cytotoxicity, apoptosis induction, tumor cell migration inhibition and expression analysis of proliferation and migration-related genes.

RESULTS

Our results revealed that all treatments were non-cytotoxic except for dichloromethane fraction which exhibited moderate cytotoxic activity. Caspase-independent apoptosis was induced by total ethanol and dichloromethane fractions while ethyl acetate fraction induces caspase-dependent apoptosis. All treatments inhibited matrix metalloproteinase-independent migration. Petroleum ether and dichloromethane inhibited migration through the down-regulation of FGF and it could be used as anticancer therapy for VEGF-resistance patients. While ethanol inhibited tumor cell migration through down-regulation of all tested genes expression. Ether and ethyl acetate fractions exerted anti-migratory activity without affecting the tested genes. All resuls were statistically significant at p˂0.05.

CONCLUSION

Total ethanol extract is a promising non-cytotoxic anticancer agent because of its powerful apoptosis induction and capability to block tumor cell migration. Petroleum ether and ether fractions area weak non-cytotoxic anti-migratory agents. Dichloromethane could be a moderate cytotoxic anti-migratory agent induced caspase-independent apoptosis. It could be used in anticancer therapy for VEGF-resistance patients through downregulation of FGF. Ethyl acetate fraction considered a non-cytotoxic agent exerting moderate anti-migratory activity. The new sponge-derived treatments can solve different resistance problems to find a convenient treatment for each individual case using a single agent.

Poly(methacrylate citric acid) as a Dual Functional Carrier for Tumor Therapy

Owing to its pH-sensitive property and chelating Cu²⁺ effect, poly(methacrylate citric acid) (PCA) can be utilized as a dual functional nanocarrier to construct a nanodelivery system. Negatively charged carboxyl groups can interact with positively charged antineoplastic drugs through electrostatic interaction to form stable drug nanoparticles (NPs). Through drug experimental screening, doxorubicin (DOX) was selected as the model drug, PCA/DOX NPs with a diameter of 84 nm were prepared, and the drug-loading content was 68.3%. PCA/DOX NPs maintained good stability and a sustained release profile. Cell experiments presented that PCA/DOX NPs could inhibit effectively the growth of 4T1 cells; the IC₅₀ value was decreased by approximately 15-fold after incubation for 72 h. The cytotoxicity toward H9C2 was decreased significantly. Moreover, based on its ability to efficiently adsorb copper ions, PCA showed good vascular growth inhibition effect in vitro. Furthermore, animal experiments showed that PCA/DOX NPs presented stronger anticancer effects than DOX; the tumor inhibition rate was increased by 1.5-fold. Myocardial toxicity experiments also confirmed that PCA reduced the cardiotoxicity of DOX. In summary, PCA/DOX NPs show good antitumor efficacy and low toxicity, and have good potential for clinical application.

Suppressing VEGF-A/VEGFR-2 Signaling Contributes to the Anti-Angiogenic Effects of PPE8, a Novel Naphthoquinone-Based Compound

Natural naphthoquinones and their derivatives exhibit a broad spectrum of pharmacological activities and have thus attracted much attention in modern drug discovery. However, it remains unclear whether naphthoquinones are potential drug candidates for anti-angiogenic agents. The aim of this study was to evaluate the anti-angiogenic properties of a novel naphthoquinone derivative, PPE8, and explore its underlying mechanisms. Determined by various assays including BrdU, migration, invasion, and tube formation analyses, PPE8 treatment resulted in the reduction of VEGF-A-induced proliferation, migration, and invasion, as well as tube formation in human umbilical vein endothelial cells (HUVECs). We also used an aorta ring sprouting assay, Matrigel plug assay, and immunoblotting analysis to examine PPE8’s ex vivo and in vivo anti-angiogenic activities and its actions on VEGF-A signaling. It has been revealed that PPE8 inhibited VEGF-A-induced micro vessel sprouting and was capable of suppressing angiogenesis in in vivo models. In addition, PPE8 inhibited VEGF receptor (VEGFR)-2, Src, FAK, ERK1/2, or AKT phosphorylation in HUVECs exposed to VEGF-A, and it also showed significant decline in xenograft tumor growth in vivo. Taken together, these observations indicated that PPE8 may target VEGF-A–VEGFR-2 signaling to reduce angiogenesis. It also supports the role of PPE8 as a potential drug candidate for the development of therapeutic agents in the treatment of angiogenesis-related diseases including cancer.

Tanshinone IIA improves cardiac function via regulating miR-499-5p dependent angiogenesis in myocardial ischemic mice

BACKGROUND/AIMS

Myocardial ischemia-reperfusion injury leads to aggravated cardiac remodeling and heart failure. After myocardial infarction (MI), angiogenesis plays a vital role in the repair and regeneration of tissue. The purpose of the current study was to determine the effect of Tanshinone IIA (Tan IIA) on angiogenesis and elucidate its related mechanism.

METHODS

The C57BL/6 mice MI model was established to evaluate the therapeutic effect of Tan IIA in vivo. MicroRNA (miRNA) microarray and bioinformatics analysis were performed to determine the differential expressions of miRNAs after Tan IIA administration. Cell proliferation, migration, and angiogenesis capacity were detected by EdU, Transwell, and Tube formation assay in vitro, respectively. The relationship between miR-499-5p (miR-499) and paired phosphate and tension homolog deleted on chromosome ten (PTEN) was confirmed by using a Dual-luciferase reporter assay.

RESULTS

Our results showed that Tan IIA administration improved cardiac function after MI by activating angiogenesis. Further miRNA microarray and bioinformatics analysis revealed that miR-499 was significantly down-regulated, while PTEN was remarkably upregulated after Tan IIA administration post-MI. In addition, we found that miR-499 knock-down effectively promotes cell proliferation, migration, and tube formation ability of HUVECs. Dual-luciferase reporter assay demonstrated that PTEN contains a direct binding site for miR-499-5p.

CONCLUSION

Tan IIA improves cardiac function post-MI by inducing angiogenesis. In terms of the mechanism, Tan IIA promotes therapeutic angiogenesis by regulating miR-499-5p/PTEN signaling pathway.

Biological aspects in controlling angiogenesis: current progress

All living beings continue their life by receiving energy and by excreting waste products. In animals, the arteries are the pathways of these transfers to the cells. Angiogenesis, the formation of the arteries by the development of pre-existed parental blood vessels, is a phenomenon that occurs naturally during puberty due to certain physiological processes such as menstruation, wound healing, or the adaptation of athletes' bodies during exercise. Nonetheless, the same life-giving process also occurs frequently in some patients and, conversely, occurs slowly in some physiological problems, such as cancer and diabetes, so inhibiting angiogenesis has been considered to be one of the important strategies to fight these diseases. Accordingly, in tissue engineering and regenerative medicine, the highly controlled process of angiogenesis is very important in tissue repairing. Excessive angiogenesis can promote tumor progression and lack of enough angiogensis can hinder tissue repair. Thereby, both excessive and deficient angiogenesis can be problematic, this review article introduces and describes the types of factors involved in controlling angiogenesis. Considering all of the existing strategies, we will try to lay out the latest knowledge that deals with stimulating/inhibiting the angiogenesis. At the end of the article, owing to the early-reviewed mechanical aspects that overshadow angiogenesis, the strategies of angiogenesis in tissue engineering will be discussed.

A comprehensive insight into the antineoplastic activities and molecular mechanisms of deoxypodophyllotoxin: Recent trends, challenges, and future outlook

Lignans constitute an important group of polyphenols, which have been demonstrated to potently suppress cancer cell proliferation. Numerous in vitro and in vivo studies indicate that deoxypodophyllotoxin as a natural lignan possesses potent anticancer activities against various types of human cancer. The purpose of current review is to provide the reader with the latest findings in understanding the anticancer effects and molecular mechanisms of deoxypodophyllotoxin. This review comprehensively describes the influence of deoxypodophyllotoxin on signaling cascades and molecular targets implicated in cancer cell proliferation and invasion. A number of various signaling molecules and pathways, including apoptosis, necroptosis, cell cycle, angiogenesis, vascular disruption, ROS, MMPs, glycolysis, and microtubules as well as NF-κB, PI3K/Akt/mTOR, and MAPK cascades have been reported to be responsible for the anticancer activities of deoxypodophyllotoxin. The results of present review suggest that the cyclolignan deoxypodophyllotoxin can be developed as a novel and potent anticancer agent, especially as an alternative option for treatment of resistant tumors to chemotherapy.

A first-in-human Phase I dose-escalation trial of the novel therapeutic peptide, ALM201, demonstrates a favourable safety profile in unselected patients with ovarian cancer and other advanced solid tumours

Background

We aimed to assess the safety, tolerability and pharmacokinetics of a novel anti-angiogenic peptide.

Methods

We used an open-label, multicentre, dose-escalation Phase I trial design in patients with solid tumours. ALM201 was administered subcutaneously once daily for 5 days every week in unselected patients with solid tumours.

Results

Twenty (8 male, 12 female) patients with various solid tumours were treated (18 evaluable for toxicity) over eight planned dose levels (10–300 mg). ALM201 was well-tolerated at all dose levels without CTCAE grade 4 toxicities. Adverse events were predominantly grades 1–2, most commonly, localised injection-site reactions (44.4%), vomiting (11%), fatigue (16.7%), arthralgia (5.6%) and headache (11%). Thrombosis occurred in two patients at the 100 mg and 10 mg dose levels. The MTD was not reached, and a recommended Phase II dose (RP2D) based on feasibility was declared. Plasma exposure increased with dose (less than dose-proportional at the two highest dose levels). No peptide accumulation was evident. The median treatment duration was 11.1 (range 3–18) weeks. Four of 18 evaluable patients (22%) had stable disease.

Conclusions

Doses up to 300 mg of ALM201 subcutaneously are feasible and well-tolerated. Further investigation of this agent in selected tumour types/settings would benefit from patient-selection biomarkers.

Cancer combination therapies by angiogenesis inhibitors; a comprehensive review

Abnormal vasculature is one of the most conspicuous traits of tumor tissue, largely contributing to tumor immune evasion. The deregulation mainly arises from the potentiated pro-angiogenic factors secretion and can also target immune cells' biological events, such as migration and activation. Owing to this fact, angiogenesis blockade therapy was established to fight cancer by eliminating the nutrient and oxygen supply to the malignant cells by impairing the vascular network. Given the dominant role of vascular-endothelium growth factor (VEGF) in the angiogenesis process, the well-known anti-angiogenic agents mainly depend on the targeting of its actions. However, cancer cells mainly show resistance to anti-angiogenic agents by several mechanisms, and also potentiated local invasiveness and also distant metastasis have been observed following their administration. Herein, we will focus on clinical developments of angiogenesis blockade therapy, more particular, in combination with other conventional treatments, such as immunotherapy, chemoradiotherapy, targeted therapy, and also cancer vaccines. Video abstract.

Tumor immunotherapies by immune checkpoint inhibitors (ICIs); the pros and cons

The main breakthrough in tumor immunotherapy was the discovery of immune checkpoint (IC) proteins, which act as a potent suppressor of the immune system by a myriad of mechanisms. After that, scientists focused on the immune checkpoint molecules mainly. Thereby, much effort was spent to progress novel strategies for suppressing these inhibitory axes, resulting in the evolution of immune checkpoint inhibitors (ICIs). Then, ICIs have become a promising approach and shaped a paradigm shift in tumor immunotherapies. CTLA-4 plays an influential role in attenuation of the induction of naïve and memory T cells by engagement with its responding ligands like B7-1 (CD80) and B7-2 (CD86). Besides, PD-1 is predominantly implicated in adjusting T cell function in peripheral tissues through its interaction with programmed death-ligand 1 (PD-L1) and PD-L2. Given their suppressive effects on anti-tumor immunity, it has firmly been documented that ICIs based therapies can be practical and rational therapeutic approaches to treat cancer patients. Nonetheless, tumor inherent or acquired resistance to ICI and some treatment-related toxicities restrict their application in the clinic. The current review will deliver a comprehensive overview of the ICI application to treat human tumors alone or in combination with other modalities to support more desired outcomes and lower toxicities in cancer patients. Video Abstract.

Destruction of tumor vasculature by vascular disrupting agents in overcoming the limitation of EPR effect

Nanomedicine greatly improves the efficiency in the delivery of antitumor drugs into the tumor, but insufficient tumoral penetration impairs the therapeutic efficacy of most nanomedicines. Vascular disrupting agent (VDA) nanomedicines are distributed around the tumor vessels due to the low tissue penetration in solid tumors, and the released drugs can selectively destroy immature tumor vessels and block the supply of oxygen and nutrients, leading to the internal necrosis of the tumors. VDAs can also improve the vascular permeability of the tumor, further increasing the extravasation of VDA nanomedicines in the tumor site, markedly reducing the dependence of nanomedicines on the enhanced permeability and retention effect (EPR effect). This review highlights the progress of VDA nanomedicines in recent years and their application in cancer therapy. First, the mechanisms of different VDAs are introduced. Subsequently, different strategies of delivering VDAs are described. Finally, multiple combination strategies with VDA nanomedicines in cancer therapy are described in detail.

Characterization With KRAS Mutant Is a Critical Determinant in Immunotherapy and Other Multiple Therapies for Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a frequent type of cancer, which is mainly characterized clinically by high aggressiveness and high mortality. KRAS oncoprotein is the most common molecular protein detected in NSCLC, accounting for 25% of all oncogenic mutations. Constitutive activation of the KRAS oncoprotein triggers an intracellular cascade in cancer cells, leading to uncontrolled cell proliferation of cancer cells and aberrant cell survival states. The results of multiple clinical trials have shown that different KRAS mutation subtypes exhibit different sensitivities to different chemotherapy regimens. Meanwhile, anti-angiogenic drugs have shown differential efficacy for different subtypes of KRAS mutated lung cancer. It was explored to find if the specificity of the KRAS mutation subtype would affect PD-L1 expression, so immunotherapy would be of potential clinical value for the treatment of some types of KRAS mutations. It was discovered that the specificity of the KRAS mutation affected PD-L1, which opened up immunotherapy as a potential clinical treatment option. After several breakthrough studies, the preliminary test data of many early clinical trials showed that it is possible to directly inhibit KRAS G12C mutation, which has been proved to be a targeted treatment that is suitable for about 10%-12% of patients with advanced NSCLC, having a significant impact on the prolongation of their survival and the improvement of their quality of life. This article reviews the latest progress of treatments for NSCLC with KRAS mutation, in order to gain insight into the biological diversity of lung cancer cells and their potential clinical implications, thereby enabling individualized treatment for patients with KRAS-mutant NSCLC.

Conjugation of VEGFR1/R2-targeting peptide with gold nanoparticles to enhance antiangiogenic and antitumoral activity

BACKGROUND

Inhibition of tumor angiogenesis through simultaneous targeting of vascular endothelial growth factor receptor (VEGFR)-1 and -2 is highly efficacious. An antagonist peptide of VEGFA/VEGFB, referred to as VGB3, can recognize and neutralize both VEGFR1 and VEGFR2 on the endothelial and tumoral cells, thereby inhibits angiogenesis and tumor growth. However, improved efficacy and extending injection intervals is required for its clinical translation. Given that gold nanoparticles (GNPs) can enhance the efficacy of biotherapeutics, we conjugated VGB3 to GNPs to enhance its efficacy and extends the intervals between treatments without adverse effects.

RESULTS

GNP-VGB3 bound to VEGFR1 and VEGFR2 in human umbilical vein endothelial (HUVE) and 4T1 mammary carcinoma cells. GNP-VGB3 induced cell cycle arrest, ROS overproduction and apoptosis and inhibited proliferation and migration of endothelial and tumor cells more effectively than unconjugated VGB3 or GNP. In a murine 4T1 mammary carcinoma tumor model, GNP-VGB3 more strongly than VGB3 and GNP inhibited tumor growth and metastasis, and increased animal survival without causing weight loss. The superior antitumor effects were associated with durable targeting of VEGFR1 and VEGFR2, thereby inhibiting signaling pathways of proliferation, migration, differentiation, epithelial-to-mesenchymal transition, and survival in tumor tissues. MicroCT imaging and inductively coupled plasma mass spectrometry showed that GNP-VGB3 specifically target tumors and exhibit greater accumulation within tumors than the free GNPs.

CONCLUSION

Conjugation to GNPs not only improved the efficacy of VGB3 peptide but also extended the intervals between treatments without adverse effects. These results suggest that GNP-VGB3 is a promising candidate for clinical translation.

Combination therapy with immune checkpoint inhibitors (ICIs); a new frontier

Recently, immune checkpoint inhibitors (ICIs) therapy has become a promising therapeutic strategy with encouraging therapeutic outcomes due to their durable anti-tumor effects. Though, tumor inherent or acquired resistance to ICIs accompanied with treatment-related toxicities hamper their clinical utility. Overall, about 60-70% of patients (e.g., melanoma and lung cancer) who received ICIs show no objective response to intervention. The resistance to ICIs mainly caused by alterations in the tumor microenvironment (TME), which in turn, supports angiogenesis and also blocks immune cell antitumor activities, facilitating tumor cells' evasion from host immunosurveillance. Thereby, it has been supposed and also validated that combination therapy with ICIs and other therapeutic means, ranging from chemoradiotherapy to targeted therapies as well as cancer vaccines, can capably compromise tumor resistance to immune checkpoint blocked therapy. Herein, we have focused on the therapeutic benefits of ICIs as a groundbreaking approach in the context of tumor immunotherapy and also deliver an overview concerning the therapeutic influences of the addition of ICIs to other modalities to circumvent tumor resistance to ICIs.

Circ_0000620 acts as an oncogenic factor in gastric cancer through regulating MMP2 expression via sponging miR-671-5p

BACKGROUND

Gastric cancer (GC) is one of the most common cancers in the digestive system. Circular RNAs (circRNAs) have been found to function as important regulators in the pathogenesis of GC. This study focused on the biological role and molecular mechanism of circ_0000620 in GC progression.

METHODS

The expression levels of circ_0000620, microRNA-671-5p (miR-671-5p) and Matrix MetalloProteinase 2 (MMP2) were measured by quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) assay or western blot. The stability of circ_0000620 was confirmed by Ribonuclease R (RNase R) assay. The protein levels were determined by western blot assay. Cell viability, colony formation, cell migratory ability, cell invasive ability and tube formation capacity were respectively examined by CCK-8 assay, colony formation assay, wound healing assay, transwell invasion assay and tube formation assay. The interaction between miR-671-5p and circ_0000620 or MMP2 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay. The role of circ_0000620 in GC undefined was explored by xenograft tumor assay.

RESULTS

Circ_0000620 was conspicuously upregulated in GC tissues and cells. Circ_0000620 knockdown reduced cell viability, colony formation, migration, invasion and tube formation capacity of GC cells in vitro. Furthermore, MMP2 was upregulated in GC and MMP2 overexpression reversed the anti-tumor response of circ_0000620 knockdown in GC progression. Moreover, circ_0000620 directly interacted with miR-671-5p and circ_0000620 downregulation regulated malignant behaviors of GC cells by upregulating miR-671-5p. In addition, silencing of circ_0000620 inhibited tumor growth in vivo.

CONCLUSIONS

Circ_0000620 knockdown inhibited the malignant development of GC partly through modulating the miR-671-5p/MMP2 axis.

Lymphatic Endothelial Markers and Tumor Lymphangiogenesis Assessment in Human Breast Cancer

Metastasis via lymphatic vessels or blood vessels is the leading cause of death for breast cancer, and lymphangiogenesis and angiogenesis are critical prerequisites for the tumor invasion–metastasis cascade. The research progress for tumor lymphangiogenesis has tended to lag behind that for angiogenesis due to the lack of specific markers. With the discovery of lymphatic endothelial cell (LEC) markers, growing evidence demonstrates that the LEC plays an active role in lymphatic formation and remodeling, tumor cell growth, invasion and intravasation, tumor–microenvironment remodeling, and antitumor immunity. However, some studies have drawn controversial conclusions due to the variation in the LEC markers and lymphangiogenesis assessments used. In this study, we review recent findings on tumor lymphangiogenesis, the most commonly used LEC markers, and parameters for lymphangiogenesis assessments, such as the lymphatic vessel density and lymphatic vessel invasion in human breast cancer. An in-depth understanding of tumor lymphangiogenesis and LEC markers can help to illustrate the mechanisms and distinct roles of lymphangiogenesis in breast cancer progression, which will help in exploring novel potential predictive biomarkers and therapeutic targets for breast cancer.

Role of MicroRNAs and Long Non-Coding RNAs in Regulating Angiogenesis in Human Breast Cancer- A Molecular Medicine Perspective

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are proficient in regulating gene expression post-transcriptionally. Considering the recent trend in exploiting non-coding RNAs (ncRNAs) as cancer therapeutics, the potential use of miRNAs and lncRNAs as biomarkers and novel therapeutic agents against angiogenesis is an important scientific aspect. An estimated 70% of the genome is actively transcribed, only 2% of which codes for known protein-coding genes. Long noncoding RNAs (lncRNAs) are a large and diverse class of RNAs > 200 nucleotides in length, and not translated into protein, and are of utmost importance and it governs the expression of genes in a temporal, spatial, and cell context-dependent manner. Angiogenesis is an essential process for organ morphogenesis and growth during development, and it is relevant during the repair of wounded tissue in adults. It is coordinated by an equilibrium of pro-and anti-angiogenic factors; nevertheless, when affected, it promotes several diseases, including breast cancer. Signaling pathways involved here are tightly controlled systems that regulate the appropriate timing of gene expression required for the differentiation of cells down a particular lineage essential for proper tissue development. Lately, scientific reports are indicating that ncRNAs, such as miRNAs, and lncRNAs, play critical roles in angiogenesis related to breast cancer. The specific roles of various miRNAs and lncRNAs in regulating angiogenesis in breast cancer, with particular focus on the downstream targets and signaling pathways regulated by these ncRNAs with molecular medicine perspective, are highlighted in this write-up.

The Dual Effect of the BMP9-ALK1 Pathway in Blood Vessels: An Opportunity for Cancer Therapy Improvement?

Simple Summary

The modulation of tumor blood vessels is a great opportunity for improving cancer therapies. Understanding the cellular and molecular players that regulate the biology of tumor blood vessels and tumor angiogenesis is necessary for the development of new anti-tumor strategies. Bone morphogenetic protein 9 (BMP9) is a circulating factor with multiple effects in vascular biology through its receptor activin receptor-like kinase 1 (ALK1). In this review, we give an overview of the possible benefits of modulating BMP9–ALK1 functions for cancer therapy improvement.

Abstract

The improvement of cancer therapy efficacy, the extension of patient survival and the reduction of adverse side effects are major challenges in cancer research. Targeting blood vessels has been considered a promising strategy in cancer therapy. Since the tumor vasculature is disorganized, leaky and triggers immunosuppression and tumor hypoxia, several strategies have been studied to modify tumor vasculature for cancer therapy improvement. Anti-angiogenesis was first described as a mechanism to prevent the formation of new blood vessels and prevent the oxygen supply to tumor cells, showing numerous limitations. Vascular normalization using low doses of anti-angiogenic drugs was purposed to overcome the limitations of anti-angiogenic therapies. Other strategies such as vascular promotion or the induction of high endothelial venules are being studied now to improve cancer therapy. Bone morphogenetic protein 9 (BMP9) exerts a dual effect through the activin receptor-like kinase 1 (ALK1) receptor in blood vessel maturation or activation phase of angiogenesis. Thus, it is an interesting pathway to target in combination with chemotherapies or immunotherapies. This review manuscript explores the effect of the BMP9–ALK1 pathway in tumor angiogenesis and the possible usefulness of targeting this pathway in anti-angiogenesis, vascular normalization or vascular promotion therapies.