Vascular endothelial growth factors and receptors: anti-angiogenic therapy in the treatment of cancer

Recent Advances in Targeted Therapies for Infantile Hemangiomas

Targeted therapy for infantile hemangiomas (IHs) has been extensively studied as they can concentrate drugs, increase therapeutic efficacy and reduce drug dosage. Meanwhile, they can extend drug release times, enhance drug stability, decrease dosing frequency, and improve patient compliance. Moreover, carriers made from biocompatible materials reduced drug immunogenicity, minimizing adverse reactions. However, current targeted formulations still face numerous challenges such as the non-absolute safety of carrier materials; the need to further increase drug loading capacity; the limitation of animal hemangioma models in fully replicating the biological properties of human infantile hemangiomas; the establishment of models for deep-seated hemangiomas with high incidence rates; and the development of more specific targets or markers. In this review, we provided a brief overview of the characteristics of IHs and summarized the past decade's advances, advantages, and targeting strategies of targeted drug delivery systems for IHs and discussed their applications in the treatment of IHs. Furthermore, the goal is to provide a reference for further research and application in this field.

New 2-oxoindole derivatives as multiple PDGFRα/ß and VEGFR-2 tyrosine kinase inhibitors

Two new series of N-aryl acetamides 6a-o and benzyloxy benzylidenes 9a-p based 2-oxoindole derivatives were designed as potent antiproliferative multiple kinase inhibitors. The results of one-dose NCI antiproliferative screening for compounds 6a-o and 9a-p elucidated that the most promising antiproliferative scaffolds were 6f and 9f, which underwent five-dose testing. Notably, the amido congener 6f was the most potent derivative towards pancreatic ductal adenocarcinoma MDA-PATC53 and PL45 cell lines (IC50 = 1.73 µM and 2.40 µM, respectively), and the benzyloxy derivative 9f was the next potent one with IC50 values of 2.85 µM and 2.96 µM, respectively. Both compounds 6f and 9f demonstrated a favorable safety profile when tested against normal prostate epithelial cells (RWPE-1). Additionally, compound 6f displayed exceptional selectivity as a multiple kinase inhibitor, particularly targeting PDGFRα, PDGFRβ, and VEGFR-2 kinases, with IC50 values of 7.41 nM, 6.18 nM, and 7.49 nM, respectively. In contrast, the reference compound Sunitinib exhibited IC50 values of 43.88 nM, 2.13 nM, and 78.46 nM against the same kinases. The derivative 9f followed closely, with IC50 values of 9.9 nM, 6.62 nM, and 22.21 nM for the respective kinases. Both 6f and 9f disrupt the G2/M cell cycle transition by upregulating p21 and reducing CDK1 and cyclin B1 mRNA levels. The interplay between targeted kinases and these cell cycle regulators underpins the G2/M cell cycle arrest induced by our compounds. Also, compounds 6f and 9f fundamentally resulted in entering MDA-PATC53 cells into the early stage of apoptosis with good percentages compared to the positive control Sunitinib. The in silico molecular-docking outcomes of scaffolds 6a-o and 9a-p in VEGFR-2, PDGFRα, and PDGFRβ active sites depicted their ability to adopt essential binding interactions like the reference Sunitinib. Our designed analogs, specifically 6f and 9f, possess promising antiproliferative and kinase inhibitory properties, making them potential candidates for further therapeutic development.

"Targeted plus controlled" - Composite nano delivery system opens the tumor vascular and microenvironment normalization window for anti-tumor therapy

The bottleneck of traditional anti-tumor therapy is mainly limited by the abnormal microenvironment of tumors. Leaky vessels are difficult for drugs or immune cells to penetrate deep into tumors, but tumor cells can easily escape through which and metastasize to other organs. Reprogramming the tumor microenvironment is one of the main directions for anti-cancer research, among which, tumor vascular normalization has received increasing attention. However, how to control the dose and time of anti-angiogenic drugs for stable vascular normalizing effect limits it for further research. We developed a composite nano delivery system, P-V@MG, with double delivery function of pH-responsibility and sustained drug release. The PHMEMA shell improves amphiphilicity of nano delivery system and prolongs in vivo retention, and releases V@MG in the weakly acidic tumor microenvironment, which slowly release anti-angiogenic drugs, Vandetanib. We found that P-V@MG not only prolonged the normalization window of tumor vascular but also reprogram tumor microenvironment with increased perfusion, immune cells infiltration and relieved hypoxia, which further opened the pathway for other anti-cancer therapeutics. This synergy was proved by the improving anti-tumor efficiency by combination of P-V@MG with the doxorubicin hydrochloride in 4 T1 breast cancer model suggesting the desirable value of pro-vascular normalization nano delivery systems in the field of anti-tumor combination therapy.

Chimeric antigen receptor macrophages activated through TLR4 or IFN-γ receptors suppress breast cancer growth by targeting VEGFR2

Chimeric antigen receptor macrophage (CAR-M) is a promising immunotherapy strategy of anti-tumor due to its high infiltration, direct phagocytosis of tumor cells, immunomodulation of tumor microenvironment (TME) and linkage of innate and adaptive immunity. Here a series of novelly designed CAR-Ms by targeting vascular endothelial growth factor receptor-2 (VEGFR2), which highly expressed in tumor cells and TME, were evaluated. Their activation signals were transduced by Tlr4 or Ifn-γ receptors either alone or in combination, which were designed to mediate M1 polarization of macrophages as the downstream of lipopolysaccharide or Ifn-γ that had been widely reported. Our results showed that VEGFR2-targeting CAR-Ms could be activated under the stimulation of VEGFR2-expressing cells. They exhibited higher expression of CD86, MHCII and TNF-α in vitro and enhanced tumor suppressive abilities in vivo. Implantation of these CAR-Ms into 4T1 breast cancer-bearing mice could obviously inhibit the progression of tumor without significant toxic side effects, especially the group of mmC in which constructed with Tlr4 as the intracellular domain of CAR. In conclusion, this research provides a promising design of CAR that induce macrophages activation by Tlr4 and/or Ifn-γ receptors, and these CAR-Ms could effectively inhibit tumor growth through targeting VEGFR2.

E7050 Suppresses the Growth of Multidrug-Resistant Human Uterine Sarcoma by Inhibiting Angiogenesis via Targeting of VEGFR2-Mediated Signaling Pathways

E7050 is an inhibitor of VEGFR2 with anti-tumor activity; however, its therapeutic mechanism remains incompletely understood. In the present study, we aim to evaluate the anti-angiogenic activity of E7050 in vitro and in vivo and define the underlying molecular mechanism. It was observed that treatment with E7050 markedly inhibited proliferation, migration, and capillary-like tube formation in cultured human umbilical vein endothelial cells (HUVECs). E7050 exposure in the chick embryo chorioallantoic membrane (CAM) also reduced the amount of neovessel formation in chick embryos. To understand the molecular basis, E7050 was found to suppress the phosphorylation of VEGFR2 and its downstream signaling pathway components, including PLCγ1, FAK, Src, Akt, JNK, and p38 MAPK in VEGF-stimulated HUVECs. Moreover, E7050 suppressed the phosphorylation of VEGFR2, FAK, Src, Akt, JNK, and p38 MAPK in HUVECs exposed to MES-SA/Dx5 cells-derived conditioned medium (CM). The multidrug-resistant human uterine sarcoma xenograft study revealed that E7050 significantly attenuated the growth of MES-SA/Dx5 tumor xenografts, which was associated with inhibition of tumor angiogenesis. E7050 treatment also decreased the expression of CD31 and p-VEGFR2 in MES-SA/Dx5 tumor tissue sections in comparison with the vehicle control. Collectively, E7050 may serve as a potential agent for the treatment of cancer and angiogenesis-related disorders.

The β3 adrenoceptor in proliferative retinopathies: "Cinderella" steps out of its family shadow

In the retina, hypoxic condition leads to overgrowing leaky vessels resulting in altered metabolic supply that may cause impaired visual function. Hypoxia-inducible factor-1 (HIF-1) is a central regulator of the retinal response to hypoxia by activating the transcription of numerous target genes, including vascular endothelium growth factor, which acts as a major player in retinal angiogenesis. In the present review, oxygen urge by the retina and its oxygen sensing systems including HIF-1 are discussed in respect to the role of the beta-adrenergic receptors (β-ARs) and their pharmacologic manipulation in the vascular response to hypoxia. In the β-AR family, β1- and β2-AR have long been attracting attention because their pharmacology is intensely used for human health, while β3-AR, the third and last cloned receptor is no longer increasingly emerging as an attractive target for drug discovery. Here, β3-AR, a main character in several organs including the heart, the adipose tissue and the urinary bladder, but so far a supporting actor in the retina, has been thoroughly examined in respect to its function in retinal response to hypoxia. In particular, its oxygen dependence has been taken as a key indicator of β3-AR involvement in HIF-1-mediated responses to oxygen. Hence, the possibility of β3-AR transcription by HIF-1 has been discussed from early circumstantial evidence to the recent demonstration that β3-AR acts as a novel HIF-1 target gene by playing like a putative intermediary between oxygen levels and retinal vessel proliferation. Thus, targeting β3-AR may implement the therapeutic armamentarium against neovascular pathologies of the eye.

Imaging strategies for receptor tyrosine kinase dimers in living cells

Receptor tyrosine kinases (RTKs) are the essential regulators of cell signal transduction pathways and play important roles in biological processes. RTK dimerization is generally considered the first step in receptor activation and cell communication. And the abnormal expression of RTK dimers is closely related to the occurrence and development of many diseases. Therefore, the visualization of RTK dimerization is of great significance for monitoring physiological processes. The genetic and nongenetic imaging strategies have attracted widespread attention due to their high efficiency and high sensitivity. In this review, the RTKs and their dimers as well as the advances in strategies for imaging RTK dimers are introduced. Furthermore, we analyze the limitations of existing imaging strategies and put forward suggestions for the future development of imaging probes. We expect that this review will inspire more in-depth investigation of RTK dimers, which will also broaden the application of strategies of RTK dimers in biomedical areas.

Peptide Lv augments intermediate-conductance calcium-dependent potassium channels (KCa3.1) in endothelial cells to promote angiogenesis

Peptide Lv is a small endogenous secretory peptide that is expressed in various tissues and conserved across different species. Patients with diabetic retinopathy, an ocular disease with pathological angiogenesis, have upregulated peptide Lv in their retinas. The pro-angiogenic activity of peptide Lv is in part through promoting vascular endothelial cell (EC) proliferation, migration, and sprouting, but its molecular mechanism is not completely understood. This study aimed to decipher how peptide Lv promotes EC-dependent angiogenesis by using patch-clamp electrophysiological recordings, Western immunoblotting, quantitative PCR, and cell proliferation assays in cultured ECs. Endothelial cells treated with peptide Lv became significantly hyperpolarized, an essential step for EC activation. Treatment with peptide Lv augmented the expression and current densities of the intermediate-conductance calcium-dependent potassium (KCa3.1) channels that contribute to EC hyperpolarization but did not augment other potassium channels. Blocking KCa3.1 attenuated peptide Lv-elicited EC proliferation. These results indicate that peptide Lv-stimulated increases of functional KCa3.1 in ECs contributes to EC activation and EC-dependent angiogenesis.

New 1,2,3-Triazole-Coumarin-Glycoside Hybrids and Their 1,2,4-Triazolyl Thioglycoside Analogs Targeting Mitochondria Apoptotic Pathway: Synthesis, Anticancer Activity and Docking Simulation

Toxicity and resistance to newly synthesized anticancer drugs represent a challenging phenomenon of intensified concern arising from variation in drug targets and consequently the prevalence of the latter concern requires further research. The current research reports the design, synthesis, and anticancer activity of new 1,2,3-triazole-coumarin-glycosyl hybrids and their 1,2,4-triazole thioglycosides as well as acyclic analogs. The cytotoxic activity of the synthesized products was studied against a panel of human cancer cell lines. Compounds 8, 10, 16 and 21 resulted in higher activities against different human cancer cells. The impact of the hybrid derivative 10 upon different apoptotic protein markers, including cytochrome c, Bcl-2, Bax, and caspase-7 along with its effect on the cell cycle was investigated. It revealed a mitochondria-apoptotic effect on MCF-7 cells and had the ability to upregulate pro-apoptotic Bax protein and downregulate anti-apoptotic Bcl-2 protein and thus implies the apoptotic fate of the cells. Furthermore, the inhibitory activities against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases for 8, 10 and 21 were studied to detect the mechanism of their high potency. The coumarin-triazole-glycosyl hybrids 8 and 10 illustrated excellent broad inhibitory activity (IC₅₀= 0.22 ± 0.01, 0.93 ± 0.42 and 0.24 ± 0.20 μM, respectively, for compound 8), (IC₅₀ = 0.12 ± 0.50, 0.79 ± 0.14 and 0.15± 0. 60 μM, respectively, for compound 10), in comparison with the reference drugs, erlotinib, sorafenib and roscovitine (IC₅₀ = 0.18 ± 0.05, 1.58 ± 0.11 and 0.46 ± 0.30 μM, respectively). In addition, the docking study was simulated to afford better rationalization and put insight into the binding affinity between the promising derivatives and their targeted enzymes and that might be used as an optimum lead for further modification in the anticancer field.

The prognostic significance of inflammation-immunity-nutrition score on postoperative survival and recurrence in hepatocellular carcinoma patients

Background

Inflammation, immunity, and nutrition status play important roles in tumorigenesis, progression, and metastasis. This study aimed to evaluate the prognostic value of Inflammation-Immunity-Nutrition Score (IINS) for overall survival (OS) and progression-free survival (PFS) in patients with hepatocellular carcinoma (HCC) undergoing radical surgery.

Methods

A total of 204 HCC patients who met the criteria were included in this retrospective study: 144 in the prediction model and 60 in the validation model. IINS was constructed based on the sum of classification scores of preoperative high-sensitivity C-reactive protein (hsCRP), lymphocyte (LYM), and albumin (ALB). The associations between the IINS group and the clinicopathologic characteristics were analyzed using Pearson’s χ2 test or Fisher’s exact test. Multivariate Cox regression analysis was used to evaluate variables significant on univariate analysis. Kaplan-Meier survival curves were conducted to investigate the prognostic values of IINS, Alpha-fetoprotein (AFP) and IINS-AFP classification. The prognostic performances of all the potential prognostic factors were further compared by receiver operating characteristic (ROC) curve, and time-dependent ROC curve. The internal validation and external validation were used to ensure the credibility of this prediction model.

Results

The patients were divided into low and high IINS groups according to the median of IINS. According to multivariate Cox regression analyses, the Barcelona Clinic Liver Cancer (BCLC) Stage (P=0.003), AFP (P=0.013), and IINS (P=0.028) were independent prognostic factors for OS, and BCLC Stage (P=0.009), microvascular invasion (P=0.030), and IINS (P=0.031) were independent prognostic factors for PFS. High IINS group were associated with significantly worse OS and PFS compared with low IINS group (P<0.001; P=0.004). In terms of clinical prognosis, IINS-AFP classification was good in group I, moderate in group II, and poor in group III. Group I had a longer OS (P<0.001) and PFS (P=0.008) compared with group II and III. ROC analysis revealed that IINS-AFP classification had a better prognostic performance for OS (AUC: 0.767) and PFS (AUC: 0.641) than other predictors, excluding its slightly lower predictive power for PFS than IINS. The time-dependent ROC curves also showed that both IINS (12-month AUC: 0.650; 24-month AUC: 0.670; 36-month AUC: 0.880) and IINS-AFP classification (12-month AUC: 0.720; 24-month AUC: 0.760; 36-month AUC: 0.970) performed well in predicting OS for HCC patients. Furthermore, the internal validation and external validation proved that IINS had good predictive performance, strong internal validity and external applicability, and could be used to establish the prediction model.

Conclusion

Inflammation-immunity-nutrition score could be a powerful clinical prognostic indicator in HCC patients undergoing radical surgery. Furthermore, IINS-AFP classification presents better prognostic performance than IINS or AFP alone, and might serve as a practical guidance to help patients adjust treatment and follow-up strategies to improve future outcomes.

An Injectable Hydrogel to Modulate T Cells for Cancer Immunotherapy

T cell exhaustion caused by mitochondrial dysfunction is the major obstacle of T cells-based cancer immunotherapy. Besides exhausted T cells, the insufficient major histocompatibility complex class I (MHC I) on tumor cells leads to inefficient T cell recognition of tumor cells, compromising therapeutic efficacy. Therapeutic platform to regulate T cell exhaustion and MHC I expression for boosting T cells-based cancer immunotherapy has not been realized up to date. Herein, an injectable hydrogel is designed to simultaneously tune T cell exhaustion and MHC I expression for amplified cancer immunotherapy. The hydrogel is in situ constructed in tumor site by utilizing oxidized sodium alginate-modified tumor cell membrane vesicle (O-TMV) as a gelator, where axitinib is encapsulated in the lipid bilayer of O-TMV while 4-1BB antibody and proprotein convertase subtilisin/kexin type 9 inhibitor PF-06446846 nanoparticles are present in the cavities of hydrogel. After immune response trigged by O-TMV antigen, the 4-1BB antibody-promoted T cell mitochondrial biogenesis and the axitinib-lowered hypoxia synergistically reverse T cell exhaustion while the PF-06446846-amplified MHC I expression facilitates T cell recognition of tumor cells, demonstrating a powerful immunotherapeutic efficacy. This strategy on reprograming T cell exhaustion and improving T cell potency offers new concept for T cells-based cancer immunotherapy.

CD146 as a promising therapeutic target for retinal and choroidal neovascularization diseases

Blood vessel dysfunction causes several retinal diseases, including diabetic retinopathy, familial exudative vitreoretinopathy, macular degeneration and choroidal neovascularization in pathological myopia. Vascular endothelial growth factor (VEGF)-neutralizing proteins provide benefits in most of those diseases, yet unsolved haemorrhage and frequent intraocular injections still bothered patients. Here, we identified endothelial CD146 as a new target for retinal diseases. CD146 expression was activated in two ocular pathological angiogenesis models, a laser-induced choroid neovascularization model and an oxygen-induced retinopathy model. The absence of CD146 impaired hypoxia-induced cell migration and angiogenesis both in cell lines and animal model. Preventive or therapeutic treatment with anti-CD146 antibody AA98 significantly inhibited hypoxia-induced aberrant retinal angiogenesis in two retinal disease models. Mechanistically, under hypoxia condition, CD146 was involved in the activation of NFκB, Erk and Akt signalling pathways, which are partially independent of VEGF. Consistently, anti-CD146 therapy combined with anti-VEGF therapy showed enhanced impairment effect of hypoxia-induced angiogenesis in vitro and in vivo. Given the critical role of abnormal angiogenesis in retinal and choroidal diseases, our results provide novel insights into combinatorial therapy for neovascular fundus diseases.

Novel 1,2,3-Triazole-Coumarin Hybrid Glycosides and Their Tetrazolyl Analogues: Design, Anticancer Evaluation and Molecular Docking Targeting EGFR, VEGFR-2 and CDK-2

This study represents the design and synthesis of a new set of triazole-coumarin-glycosyl hybrids and their tetrazole hybrid analogues possessing various sugar moieties and modified analogues. All the newly synthesized derivatives were screened for their cytotoxic activities against a panel of human cancer cell lines. The coumarin derivatives 10, 13 and 15 derivatives revealed potent cytotoxic activities against Paca-2, Mel-501, PC-3 and A-375 cancer cell lines. These promising analogues were further examined for their inhibitory assessment against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases. The coumarin-tetrazole 10 displayed broad superior inhibitory activity against all screened enzymes compared with the reference drugs, erlotinib, sorafenib and roscovitine, respectively. The impact of coumarin-tetrazole 10 upon cell cycle and apoptosis induction was determined to detect its mechanism of action. Additionally, it upregulated the levels of casp-3, casp-7 and cytochrome-c proteins and downregulated the PD-1 level. Finally, molecular docking study was simulated to afford better rationalization and gain insight into the binding affinity between the promising derivatives and their targeted enzymes, which could be used as an optimum lead for further modification in the anticancer field.

Synthesis, biological evaluation, and molecular docking of new series of antitumor and apoptosis inducers designed as VEGFR-2 inhibitors

Based on quinazoline, quinoxaline, and nitrobenzene scaffolds and on pharmacophoric features of VEGFR-2 inhibitors, 17 novel compounds were designed and synthesised. VEGFR-2 IC₅₀ values ranged from 60.00 to 123.85 nM for the new derivatives compared to 54.00 nM for sorafenib. Compounds 15_a, 15_b, and 15_d showed IC₅₀ from 17.39 to 47.10 µM against human cancer cell lines; hepatocellular carcinoma (HepG2), prostate cancer (PC3), and breast cancer (MCF-7). Meanwhile, the first in terms of VEGFR-2 inhibition was compound 15_d which came second with regard to antitumor assay with IC₅₀ = 24.10, 40.90, and 33.40 µM against aforementioned cell lines, respectively. Furthermore, Compound 15_d increased apoptosis rate of HepG2 from 1.20 to 12.46% as it significantly increased levels of Caspase-3, BAX, and P53 from 49.6274, 40.62, and 42.84 to 561.427, 395.04, and 415.027 pg/mL, respectively. Moreover, 15_d showed IC₅₀ of 253 and 381 nM against HER2 and FGFR, respectively.

Apoptotic and anti-angiogenic effects of propolis against human bladder cancer: molecular docking and in vitro screening

INTRODUCTION

Bladder cancer is still of unknown initiation and progression, it is difficult to treat the patient once bladder cancer have a distant metastasis.

MATERIALS AND METHODS

In the present study, propolis extract was evaluated against bladder cancer cells (T24). Two independent pathways were investigated, apoptosis and angiogenesis, Bax, Bcl-2, P53, and caspase-3 for apoptosis, vascular endothelial growth factor receptor and protein kinase A as angiogenesis potential targets.

OBJECTIVES

Molecular docking studies will be conducted for the major known constituents of Egyptian propolis into apoptotic and angiogenic protein targets, to give better insights to the possible binding mode and interactions and investigate the ability of propolis constituents to target both apoptotic and angiogenic pathways.

RESULTS

Propolis showed anti-proliferative activity against T24 cancer cell line, the IC₅₀ value was 6.36 µg/ml. Also significant effects of propolis on Bax, Bcl-2, P53, and caspase-3 were observed.

DISCUSSION

These obtained results proved the ability of propolis to induce cell death. Also it has revealed noticeable effects on protein kinase A and vascular endothelial growth factor receptor.

CONCLUSION

The obtained results can encourage us to say that propolis extract can induce a programmed cell death in human bladder cancer cells, and also affect angiogenesis.

Sunitinib malate inhibits hemangioma cell growth and migration by suppressing focal adhesion kinase signaling

Sunitinib malate is a small molecule that targets multiple receptor tyrosine kinases and blocks their activity. Receptors targeted by sunitinib are implicated in tumor vascularization and are overexpressed by vascular tumors encountered in infants, namely, hemangiomas. Of note is that there is still no definitive treatment for these commonly occurring tumors of infancy. The purpose of this study was to investigate the effects of sunitinib malate on hemangioma using endothelial cells isolated from a murine model of the neoplasm (sEnd.2). The effects of the drug on cell growth were evaluated using the crystal violet assay and flow cytometry, while the scratch assay was employed to measure cell migration. Proteins associated with cell migration and angiogenesis were detected using western blotting. Sunitinib was investigated further to determine its effects on the production of reactive oxygen species, a parameter associated with the promotion of neovascularization in tumors. The results showed that sunitinib significantly reduced the growth of sEnd.2 cells by causing the cells to accumulate in the sub-G1 phase of the cell cycle, and also induced a significant decrease in the migration of these hemangioma cells (P < 0.05). The western blot assay showed a decrease in the expression of adhesion proteins, focal adhesion kinase and paxillin at IC50 doses, although the expression of cadherin did not change significantly (P < 0.05). In addition, transforming growth factor-β1 (TGF-β1) expression was decreased in sunitinib-treated cells at the same dose. The adhesion proteins as well as TGF-β1 regulate cell movement and have been implicated in tumor progression. Thus, sunitinib malate may have potential in the treatment of hemangiomas.

Phthalocyanine-based photoacoustic contrast agents for imaging and theranostics

Phthalocyanine, as an organic dye, has attracted much attention due to its high molar absorption coefficient in the near-infrared region (NIR). It is precisely because of this advantage that phthalocyanine is very beneficial to photoacoustic imaging (PAI). At present, many different strategies have been adopted to design phthalocyanine-based contrast agents with photoacoustic (PA) effect, including increasing water solubility, changing spectral properties, prolonging the circulation time, constructing activatable supramolecular nanoparticles, increasing targeting, etc. Based on this, this minireview highlighted the above ways to enhance the PA effect of phthalocyanine. What's more, the application of phthalocyanine-based PA contrast agents in biomedical imaging and image-guided phototherapy has been discussed. Finally, this minireview also provides the prospects and challenges of phthalocyanine-based PA contrast agents in order to provide some reference for the application of phthalocyanine-based PA contrast agents in biomedical imaging and guiding tumor treatment.

New quinoxaline-based VEGFR-2 inhibitors: design, synthesis, and antiproliferative evaluation with in silico docking, ADMET, toxicity, and DFT studies

A new series of 3-methylquinoxaline-based derivatives having the same essential pharmacophoric features as VEGFR-2 inhibitors have been synthesized and evaluated for their antiproliferative activities against two human cancer cell lines, MCF-7 and HepG-2. Compounds 15b and 17b demonstrated a significant antiproliferative effect with IC₅₀ ranging from 2.3 to 5.8 μM. An enzymatic assay was carried out for all the tested candidates against VEGFR-2. Compound 17b was the most potent VEGFR-2 inhibitor (IC₅₀ = 2.7 nM). Mechanistic investigation including cell cycle arrest and apoptosis was performed for compound 17b against HepG-2 cells, and the results revealed that 17b induced cell apoptosis and arrested cell cycle in the G2/M phase. Moreover, apoptosis analyses were conducted for compound 17b to evaluate its apoptotic potential. The results showed upregulation in caspase-3 and caspase-9 levels, and improving the Bax/Bcl-2 ratio by more than 10-fold. Docking studies were performed to determine the possible interaction with the VEGFR-2 active site. Further docking studies were carried out for compound 17b against cytochrome P450 to present such compounds as non-inhibitors. In silico ADMET, toxicity, and physico-chemical properties revealed that most of the synthesized members have acceptable values of drug-likeness. Finally, DFT studies were carried out to calculate the thermodynamic, molecular orbital and electrostatic potential properties.

Vascular Normalization: A New Window Opened for Cancer Therapies

Preclinical and clinical antiangiogenic approaches, with multiple side effects such as resistance, have not been proved to be very successful in treating tumor blood vessels which are important targets for tumor therapy. Meanwhile, restoring aberrant tumor blood vessels, known as tumor vascular normalization, has been shown not only capable of reducing tumor invasion and metastasis but also of enhancing the effectiveness of chemotherapy, radiation therapy, and immunotherapy. In addition to the introduction of such methods of promoting tumor vascular normalization such as maintaining the balance between proangiogenic and antiangiogenic factors and targeting endothelial cell metabolism, microRNAs, and the extracellular matrix, the latest molecular mechanisms and the potential connections between them were primarily explored. In particular, the immunotherapy-induced normalization of blood vessels further promotes infiltration of immune effector cells, which in turn improves immunotherapy, thus forming an enhanced loop. Thus, immunotherapy in combination with antiangiogenic agents is recommended. Finally, we introduce the imaging technologies and serum markers, which can be used to determine the window for tumor vascular normalization.

Treatment strategy for myocarditis in patients using immune checkpoint inhibitors or combined anti-vascular endothelial growth factor therapy by clinical severity

BACKGROUND

Combination of immune checkpoint inhibitor (ICI) and anti-vascular endothelial growth factor (VEGF) therapy has increasingly become a promising strategy in various tumors. However, the combination might be associated with increased cardiotoxicities. Myocarditis is a potentially fatal complication in cancer patients treated with ICI. Currently, there are no clear guidelines for the management of this disease nor data characterizing the clinical course of myocarditis patients due to the combination of ICI and anti-VEGF therapy.

PATIENTS AND METHODS

This study included all patients consecutively admitted to Shanghai Zhongshan Hospital, Fudan University for the diagnosis of ICI-associated myocarditis according to Bonaca's criteria. The clinical presentation and outcome of myocarditis patients were collected receiving ICI and anti-VEGF combined therapy.

RESULTS

A total of 48 patients were included (23 received combined treatment of ICI and anti-VEGF while 25 received ICI only). No differences in baseline characteristics, clinical course, and outcomes were observed among patients receiving ICI with or without anti-VEGF treatment. The patients were subdivided into 3 groups including 8 fulminant cases, 25 clinically significant cases, and 15 subclinical cases based on clinical severity. The fulminant group was associated with a higher rate of cardiovascular deaths (CVDs) compared with clinically significant and subclinical groups (87.5% versus 4.0% versus 0.0%, p < 0.01). When stratified by the dose of corticosteroids used, cases with high-dose usage were more likely to have a CVD when compared to low dose or no use and intermediate dose groups (0.0% versus 4.0% versus 57.1%, p < 0.01).

CONCLUSIONS

No significant differences between myocarditis patients receiving ICI or combined anti-VEGF therapy in terms of clinical presentation and outcome were observed. Treatment strategy for myocarditis in patients using ICI or combined anti-VEGF therapy should be based on clinical severity. Specifically, immunosuppressive therapy besides high-dose corticosteroids is needed for fulminant cases.

The Value of Preoperative Plasma VEGF Levels in Urothelial Carcinoma of the Bladder Treated with Radical Cystectomy

BACKGROUND

Elevated preoperative plasma levels of the angiogenesis-related marker VEGF have been associated with worse oncological outcomes in various malignancies.

OBJECTIVE

To investigate the predictive/prognostic role of VEGF in patients with urothelial carcinoma of the bladder (UCB) treated with radical cystectomy (RC).

DESIGN, SETTING, AND PARTICIPANTS

VEGF plasma levels were measured preoperatively in 1036 patients with UCB who underwent RC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The correlation between plasma VEGF levels and pathological and survival outcomes was assessed using logistic regression and Cox regression analyses. Discrimination was assessed using the concordance index (C index). The clinical net benefit was evaluated using decision curve analysis (DCA).

RESULTS AND LIMITATIONS

Patients with higher pretreatment plasma VEGF levels had poorer recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) according to log-rank tests (all p < 0.001). Higher VEGF levels were not independently associated with higher risk of lymph node metastasis, ≥pT3 disease, or non-organ-confined disease (all p > 0.05). Preoperative plasma VEGF levels were independently associated with RFS, CSS, and OS in preoperative and postoperative multivariable models. However, in all cases the C index increased by <0.02 and there was no improvement in net benefit on DCA. A limitation is that none of the patients received current elements of standard of care such as neoadjuvant chemotherapy.

CONCLUSIONS

Elevated plasma VEGF levels were associated with features of biologically and clinically aggressive disease such as worse survival outcomes among patients with UCB treated with RC. However, VEGF appears to have relatively limited incremental additive value in clinical use. Further study of VEGF for UCB prognostication is warranted before routine use in clinical algorithms.

PATIENT SUMMARY

Currently available models for predicting outcomes in bladder cancer are less than optimal. A protein called vascular endothelial growth factor (VEGF), which is a marker of the formation of blood vessels (angiogenesis), may have a role in predicting survival outcomes in bladder cancer.

TAKE HOME MESSAGE

Elevated plasma VEGF levels are associated with worse survival outcomes for patients with urothelial carcinoma of the bladder (UCB) treated with radical cystectomy. VEGF could be used as a part of a biomarker panel to enhance tools currently used for risk stratification for patients with UCB.

Systemic immune-inflammation index predicts prognosis of sequential therapy with sorafenib and regorafenib in hepatocellular carcinoma

Background

Regorafenib has shown promising results as a second-line therapy for patients with hepatocellular carcinoma (HCC) who progressed on sorafenib. Although there have been several data regarding the efficacy of sequential therapy with sorafenib and that of regorafenib in real-life, specific inflammation markers for predicting the prognosis have not been studied. This study aimed to investigate prognostic value of systemic inflammatory markers in patients with HCC who received sorafenib-regorafenib sequential therapy.

Methods

We retrospectively analyzed medical data of patients who received regorafenib for the treatment of HCC after sorafenib failure. Progression free survival (PFS) and overall survival (OS) were assessed using the Kaplan–Meier survival curves. Univariate and multivariate analyses were performed to analyze the factors associated with survival.

Results

A total of 58 patients who received at least one dose of regroafenib and fulfilled the eligibility criteria, good performance status (Eastern Cooperative Oncology Group [ECOG] 0–1) and preserved liver function (Child-Pugh-A), were included in the analysis. The median PFS was 3 months (95% confidence interval [CI] = 0.981–5.019) and the median OS was 8 months (95% CI = 5.761–10.239). Elevated systemic immune-inflammation index (SII ≥340) was independently associated with poor OS. In multivariate analysis, the SII (hazard ratio [HR] = 2.211, 95% CI = 1.089–4.489, P = 0.028) and alpha-fetoprotein (AFP) (HR = 2.750, 95% CI = 1.259–6.010, P = 0.011) were independent predictors of OS.

Conclusion

Elevated SII is associated with poor OS in patients with HCC who received sequential therapy with sorafenib and regorafenib. In addition, when selecting a treatment strategy, the SII can be used in combination with the AFP level as a promising prognostic tool for HCC.

Prolyl 3-Hydroxylase 2 Is a Molecular Player of Angiogenesis

Prolyl 3-hydroxylase 2 (P3H2) catalyzes the post-translational formation of 3-hydroxyproline on collagens, mainly on type IV. Its activity has never been directly associated to angiogenesis. Here, we identified P3H2 gene through a deep-sequencing transcriptome analysis of human umbilical vein endothelial cells (HUVECs) stimulated with vascular endothelial growth factor A (VEGF-A). Differently from many previous studies we carried out the stimulation not on starved HUVECs, but on cells grown to maintain the best condition for their in vitro survival and propagation. We showed that P3H2 is induced by VEGF-A in two primary human endothelial cell lines and that its transcription is modulated by VEGF-A/VEGF receptor 2 (VEGFR-2) signaling pathway through p38 mitogen-activated protein kinase (MAPK). Then, we demonstrated that P3H2, through its activity on type IV Collagen, is essential for angiogenesis properties of endothelial cells in vitro by performing experiments of gain- and loss-of-function. Immunofluorescence studies showed that the overexpression of P3H2 induced a more condensed status of Collagen IV, accompanied by an alignment of the cells along the Collagen IV bundles, so towards an evident pro-angiogenic status. Finally, we found that P3H2 knockdown prevents pathological angiogenesis in vivo, in the model of laser-induced choroid neovascularization. Together these findings reveal that P3H2 is a new molecular player involved in new vessels formation and could be considered as a potential target for anti-angiogenesis therapy.

Design and screening of a novel neuropilin-1 targeted penetrating peptide for anti-angiogenic therapy in glioma

AIMS

This study aimed to design and screen a dual functional fusion peptide that could penetrate the blood-brain barrier and target neuropilin 1 (NRP1) overexpressed in vascular endothelial cells for the anti-angiogenesis of glioma treatment.

MAIN METHODS

At the cellular level, the in vitro anti-angiogenic activity of six NRP1 targeting peptides was screened by testing the ability to inhibit the proliferation and tube formation of HUVECs. Then, the in vitro anti-angiogenic activity of two fusion peptides containing different linkers was screened by testing the ability to inhibit HUVECs proliferation, tube formation and migration. The effect of fusion peptide on VEGFR2 related signal pathway was confirmed by Western-blotting. Surface plasmon resonance technology was used to detect the affinity of the fusion peptide to NRP1. The ability of FITC-labeled peptides to penetrate cells was confirmed by cell uptake assay. By establishing an orthotopic glioma model, we evaluated the ability of FITC-labeled peptides to penetrate the blood-brain barrier and their anti-glioma growth activity in vivo.

KEY FINDINGS

We found that NRP1 targeting peptide RP7 and linker cysteine were the most suitable key components in the fusion peptide. We also found that the fusion peptide Tat-C-RP7 we constructed had the strongest ability to penetrate the blood-brain barrier and anti-angiogenic activity in vitro and in vivo.

SIGNIFICANCE

At present, NRP1 targeting peptide as a drug delivery tool and molecular probe seems to have received more attention. We constructed a fusion peptide Tat-C-RP7 with strong anti-angiogenic activity for the treatment of glioma.

Synthetic heparan sulfate ligands for vascular endothelial growth factor to modulate angiogenesis

We report the discovery of a potential heparan sulfate (HS) ligand to target several growth factors using 13 unique HS tetrasaccharide ligands. By employing an HS microarray and SPR, we deciphered the crucial structure-binding relationship of these glycans with the growth factors BMP2, VEGF₁₆₅, HB-EGF, and FGF2. Notably, GlcNHAc(6-O-SO₃^-)-IdoA(2-O-SO₃^-) (HT-2,6S-NAc) tetrasaccharide showed strong binding with the VEGF₁₆₅ growth factor. In vitro vascular endothelial cell proliferation, migration and angiogenesis was inhibited in the presence of VEGF₁₆₅ and HT-2,6S-NAc or HT-6S-NAc, revealing the potential therapeutic role of these synthetic HS ligands.

Advances in pharmacotherapeutics for hepatocellular carcinoma

INTRODUCTION

Although hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, there are limited therapeutic options for the advanced stages. Sorafenib was the first tyrosine-kinase inhibitor (TKI) approved for unresectable HCC and remained the only effective choice for a decade. The horizon of systemic treatments drastically expanded in the latest years, opening new interesting possibilities.

AREAS COVERED

In this manuscript, the authors have analysed the recent advances in pharmacotherapy for HCC, discussing their mechanisms of action, the clinical efficacy and the safety profile of currently available first, second-and third-line treatments. The authors have also analysed the role of immune system modulators, in particular immune checkpoints inhibitors (ICIs), based on the limited data published so far.

EXPERT OPINION

The emergence of new targeted therapies, such as lenvatinib, have changed the landscape of HCC therapy. Tumor extension, differences in objective response rates and adverse events profiles should be considered to tailor the choice of the first-line agent. Sorafenib remains the most studied drug, with much real-world data available. The efficacy of second line therapies has only been proven in non-responder or sorafenib-intolerant patients. Unfortunately, studies directly comparing the second-line agents regorafenib, ramucirumab and cabozantinib are still lacking.

Nanomaterials for Antiangiogenic Therapies for Cancer: A Promising Tool for Personalized Medicine

Angiogenesis is one of the hallmarks of cancer. Several studies have shown that vascular endothelium growth factor (VEGF) plays a leading role in angiogenesis progression. Antiangiogenic medication has gained substantial recognition and is commonly administered in many forms of human cancer, leading to a rising interest in cancer therapy. However, this treatment method can lead to a deteriorating outcome of resistance, invasion, distant metastasis, and overall survival relative to its cytotoxicity. Furthermore, there are significant obstacles in tracking the efficacy of antiangiogenic treatments by incorporating positive biomarkers into clinical settings. These shortcomings underline the essential need to identify additional angiogenic inhibitors that target numerous angiogenic factors or to develop a new method for drug delivery of current inhibitors. The great benefits of nanoparticles are their potential, based on their specific properties, to be effective mechanisms that concentrate on the biological system and control various important functions. Among various therapeutic approaches, nanotechnology has emerged as a new strategy for treating different cancer types. This article attempts to demonstrate the huge potential for targeted nanoparticles and their molecular imaging applications. Notably, several nanoparticles have been developed and engineered to demonstrate antiangiogenic features. This nanomedicine could effectively treat a number of cancers using antiangiogenic therapies as an alternative approach. We also discuss the latest antiangiogenic and nanotherapeutic strategies and highlight tumor vessels and their microenvironments.

The double life of TLR2

TLR2 located in the endothelium promotes angiogenesis and inflammation.

CircASH2L Promotes Ovarian Cancer Tumorigenesis, Angiogenesis, and Lymphangiogenesis by Regulating the miR-665/VEGFA Axis as a Competing Endogenous RNA

Ovarian cancer is the leading cause of gynecologic cancer-related deaths. Emerging research has revealed a close relationship between circular RNAs (circRNAs) and ovarian cancer development, metastasis, and prognosis. The objective of our research was to further explore the relationship between circASH2L and ovarian cancer. Quantitative real-time polymerase chain reaction was used to detect the differential expression of circRNAs between normal ovaries and ovarian cancer tissues. The impact of circASH2L on the proliferation, invasion, and tumorigenicity of ovarian cancer cells was evaluated using gain- and loss-of-function experiments. The molecular mechanisms of circASH2L function were investigated using bioinformatics analysis, RNA fluorescence in situ hybridization, western blots, and dual-luciferase reporter assays. The results showed that circASH2L was remarkably upregulated in ovarian cancer. The invasion and growth of ovarian cancer cells were suppressed by circASH2L knockdown in vitro, and downregulation of circASH2L restrained both angiogenesis and lymphangiogenesis of tumor xenografts in vivo. Furthermore, circASH2L was mostly distributed in the cytoplasm, where it competes with vascular endothelial growth factor A (VEGFA) for binding to miR-665. These findings indicate that circASH2L has an oncogenic function in ovarian cancer. In conclusion, circASH2L plays a critical role in regulating ovarian cancer cell tumorigenesis, angiogenesis, and lymphangiogenesis through the miR-665/VEGFA axis and, therefore, is a possible candidate target for ovarian cancer treatment.

Thrombosed orbital arteriovenous malformation in a patient with lymphangioleiomyomatosis

A 47 year-old female with lymphangioleiomyomatosis developed right periorbital pain worsened while chewing, six months prior. Neuroimaging demonstrated a heterogenous inferotemporal right orbital mass extending through the inferior orbital fissure into the temporalis fossa, with flow voids. Given the patient's past medical history, the lesion was presumed to be a perivascular epithelioid cell tumor, a manifestation of lymphangioleiomyomatosis. A lateral orbitotomy revealed a well-circumscribed bluish-red lesion with areas of hemorrhage that was resected in total. Histopathology, however, was consistent with a thrombosed orbital arteriovenous malformation likely arising from the zygomaticotemporal neurovascular bundle. Lymphangioleiomyomatosis is a rare progressive disease that causes cystic destruction of the lungs and is frequently associated with extrapulmonary tumor infiltration, typically of the kidney and liver. Lymphangiomyoleiomyomatosis cell pathogenesis includes a pro-angiogenic micro-environment, classically expressing vascular endothelial factor-C and -D, which we postulate may have contributed to the development of the orbital arteriovenous malformation.

Preclinical assessment of intravitreal ramucirumab: in vitro and in vivo safety profile

Background

Anti-angiogenic drugs remain the mainstay therapy for several vascular retinal pathologies. The repurposing of approved anti-angiogenic drugs for use in ophthalmology can increase therapeutic options and reduce costs. The purpose of this study was to investigate the ocular safety profile of intravitreal (IVT) ramucirumab, an approved anti-vascular endothelial growth factor molecule for systemic treatment, using cell culture and animal models.

Methods

The cytotoxicity of ramucirumab at different concentrations was evaluated in human retinal pigment epithelial cells (ARPE-19) using the MTT assay. In addition, 250 or 500 µg of ramucirumab or vehicle was injected in the eye of 16 chinchilla rabbits. The eyes were evaluated by ophthalmoscopy, electroretinography, spectral-domain optical coherence tomography (SD-OCT) and by light and transmission electron microscopy.

Results

Electroretinography or SD-OCT did not detect functional or morphological alterations at 24 h or one week after injection. Light and transmission electron microscopy confirmed the absence of major signs of toxicity, although we found a statistically significant reduction in ganglion cell number between the controls and the eyes that received 500 µg of ramucirumab after 7 days. Compared to lower concentrations, 500 µg of ramucirumab caused reduction in cell viability and changes in morphology in ARPE-19 cells. Compared to the baseline, ocular and serum osmolarity showed no difference after IVT injection at all timepoints.

Conclusion

In conclusion, IVT injection of ramucirumab in rabbits is safe and does not cause functional damage to the retina. At the lower dose tested in vivo (250 µg), the morphology and ultrastructural anatomy were normal at 24 h and 1 week after the injection. However, the 500 µg dose can cause a decrease in ganglion cell number seven days after the injection.

Oxygen sensing; a stunningly elegant molecular machinery highjacked in cancer

Oxygen is of fundamental importance for most living organisms, and the maintenance of oxygen homeostasis is a key physiological challenge for all large animals. Oxygen deprivation, hypoxia, is a critical component of many human diseases including cancer, heart disease, stroke, vascular disease, and anaemia. The discovery of oxygen sensing provides fundamental knowledge of a stunningly elegant molecular machinery; it also promises development of new therapeutics for serious diseases such as cancer. As a result of their impressive contributions to our understanding of the mechanisms by which cells sense oxygen and signal in hypoxia, Gregg Semenza, Peter Ratcliffe, and William Kaelin were awarded the Nobel Prize in 2019.

Efficacy and Safety of Ramucirumab in Asian and Non-Asian Patients with Advanced Hepatocellular Carcinoma and Elevated Alpha-Fetoprotein: Pooled Individual Data Analysis of Two Randomized Studies

OBJECTIVE

REACH-2 and REACH were randomized, placebo-controlled, double-blind, multicenter phase 3 trials which showed survival benefits of ramucirumab treatment in patients with advanced hepatocellular carcinoma (HCC) and elevated alpha-fetoprotein (AFP). We evaluated the efficacy and safety of ramucirumab in Asian and non-Asian patients with AFP ≥400 ng/mL from REACH-2 and REACH.

METHODS

We pooled Asian and non-Asian patients from the REACH-2 and REACH trials and performed an individual patient data meta-analysis. Overall survival (OS) and progression-free survival were evaluated using the Kaplan-Meier method. Hazard ratios (HRs) were estimated with a stratified Cox regression model.

RESULTS

In the pooled REACH-2 and REACH patient population, 291 Asian patients were randomly assigned to receive ramucirumab (n = 168) or placebo (n = 123), and 251 non-Asian patients received ramucirumab (n = 148) or placebo (n = 103). The median OS was significantly longer in the ramucirumab arm in comparison to the placebo arm for Asian patients (8.08 vs. 4.76 months, stratified HR 0.73 [95% CI 0.56-0.95], p = 0.0189) and non-Asian patients (7.98 vs. 5.22 months, stratified HR 0.65 [95% CI 0.49-0.86], p = 0.0028). The overall response rate (ORR) and disease control rate (DCR) were significantly higher in the ramucirumab arm compared to the placebo arm for Asian patients (ORR: 4.2 vs. 0.8%; DCR: 53.6 vs. 33.3%) and non-Asian patients (ORR: 6.8 vs. 1.0%; DCR: 59.5 vs. 41.7%). The most common grade ≥3 treatment-emergent adverse events reported in the ramucirumab arm were hypertension (7.7%), decreased appetite (1.2%), and ascites (1.2%) for Asian patients and hypertension (16.9%), ascites (8.8%), asthenia (4.7%), and fatigue (5.4%) for non-Asian patients.

DISCUSSION AND CONCLUSION

This pooled analysis of the REACH-2/REACH trials demonstrates significant benefits, with a manageable safety profile, of ramucirumab treatment in Asian and non-Asian patients with advanced HCC and baseline AFP ≥400 ng/mL.

Synthesis and molecular docking study of new pyrazole derivatives as potent anti-breast cancer agents targeting VEGFR-2 kinase

Based on the previous studies that revealed the valuable role of pyrazole scaffold in cancer management and VEGFR-2 inhibition, a new set of pyrazole conjugated with pyrazoline, triazolopyrimidine and pyrazolone moieties were synthesized and investigated for their anticancer efficiency against human breast cancer MCF-7. The anticancer screening revealed the significant sensitivity of breast carcinoma towards compounds 4b, 5c, 6c, 7b, 7c and 12c with IC₅₀ values ranging from 16.50 - 26.73 µM in comparison with tamoxifen (IC₅₀ = 23.31 µM). Moreover, the new analogues were further examined for their VEGFR-2 inhibitory activity, among the tested derivatives 5c, 6c, 7b, 7c and 12c displayed prominent inhibitory efficiency versus VEGFR-2 kinase with % inhibition ranging from 70 to 79%. Compounds 6c, 7c and 12c revealed inhibitory efficiency in nanomolar level with IC₅₀ (913.51, 225.17 and 828.23 nM, respectively) comparing to sorafenib (IC₅₀ = 186.54 nM). Flow cytometric analysis revealed that the promising compound 12c prompted pre-G1 apoptosis and cell growth cessation at G2/M phase and stimulated apoptosis via activation of caspase-3. Moreover, molecular docking study of the promising derivatives was performed to highlight their binding modes and interactions with the amino acid residues of VEGFR-2 enzyme.

Recognition Sites for Cancer-targeting Drug Delivery Systems

BACKGROUND

Target-homing drug delivery systems are now gaining significant attention for use as novel therapeutic approaches in antitumor targeting for cancer therapy. Numerous targeted drug delivery systems have been designed to improve the targeting effects because these systems can display a range of favorable properties, thus, providing suitable characteristics for clinical applicability of anticancer drugs, such as increasing the solubility, and improving the drug distribution at target sites. The majority of these targeting systems are designed with respect to differences between cancerous and normal tissues, for instance, the low pH of tumor tissues or overexpressed receptors on tumor cell membranes. Due to the growing number of targeting possibilities, it is important to know the tumor-specific recognition strategies for designing novel, targeted, drug delivery systems. Herein, we identify and summarize literature pertaining to various recognition sites for optimizing the design of targeted drug delivery systems to augment current chemotherapeutic approaches.

OBJECTIVE

This review focuses on the identification of the recognition sites for developing targeted drug delivery systems for use in cancer therapeutics.

METHODS

We have reviewed and compiled cancer-specific recognition sites and their abnormal characteristics within tumor tissues (low pH, high glutathione, targetable receptors, etc.), tumor cells (receptor overexpression or tumor cell membrane changes) and tumor cell organelles (nuclear and endoplasmic reticular dysregulation) utilizing existing scientific literature. Moreover, we have highlighted the design of some targeted drug delivery systems that can be used as homing tools for these recognition sites.

RESULTS AND CONCLUSION

Targeted drug delivery systems are a promising therapeutic approach for tumor chemotherapy. Additional research focused on finding novel recognition sites, and subsequent development of targeting moieties for use with drug delivery systems will aid in the evaluation and clinical application of new and improved chemotherapeutics.

Synthesis of Piperidine Conjugated Dihydroquinazolin-4(1H)-ones and their Antiproliferative Activity, Molecular Docking Studies and DFT Calculations

Background:

Xanthatin, fluoropyrimidine and thienopyrimidine, pyrazolopyrimidine, pyrimidine carboxamides, and SKLB1002 are reported as VEGFR2 tyrosine kinase inhibitors. Recently, many studies related to different heterocycles conjugated with dihydroquinazolinones are known to have very good biological activities. In this study, we are intended to explore the cytotoxic studies of piperidine conjugated dihydroquinazolinones against colorectal/colon cancer cell lines and along with molecular docking studies and DFT calculations.

Methods:

The colorectal/colon cell lines HCT116 and A549 cell lines were treated with these compounds and cytotoxic activities were evaluated by MTT dye uptake method. We performed molecular modelling for compound 3d using the Auto Dock software. The binding of compound 3d with target proteins was studied with the collection of experimentally determined PDB database. Optimized geometry by DFT calculations was performed with B3LYP/6-31G (d) basis set.

Results:

Piperidine-conjugated dihydroquinazolinone analogues displayed anticancer activity. Particularly, the compound 3d with electron-withdrawing substituents on a phenyl ring showed significant cytotoxicity against HCT116 and A549 cell lines. Molecular docking studies proved that the compound 3d has good fitting by forming hydrogen bonds with amino acid residues at the active sites of VEGFR2. The HOMO, LUMO, their energies and UV visible spectrum were predicted using DFT calculations.

Conclusion:

Four piperidine-conjugated dihydroquinazolinones were synthesized and evaluated against colorectal and colon cancer cell lines. Compound 3d significantly inhibited the growth of HCT116 and A549. Molecular docking studies displayed good fitting of compound 3d by forming different H-bonds with the amino acid at the active sites of the VEGFR2 target. Using a theoretical approach, we optimized HOMO and LUMO plots for the compound 3d.

Optical-resolution photoacoustic microscopy for monitoring vascular normalization during anti-angiogenic therapy

Monitoring the changes in tumor vascularity is important for anti-angiogenic therapy assessment with therapeutic implications. However, monitoring vascularity is quite challenging due to the lack of appropriate imaging techniques. Here, we describe a non-invasive imaging technique using optical-resolution photoacoustic microscopy (OR-PAM) to track vascular changes in prostate cancer treated with an anti-angiogenic agent, DC101, on a mouse ear xenograft model. Approximately 1-3 days after the initial therapy, OR-PAM imaging detected tumor vascular changes such as reduced vessel tortuosity, decreased vessel diameter and homogenized intratumoral vessel distribution. These observations indicated vessel normalization, which was pathologically validated as increased fractional pericyte coverage, functional perfusion and drug delivery of the vessels. After four DC101 interventions, OR-PAM imaging eventually revealed intratumoral vessel regression. Therefore, OR-PAM imaging of the vasculature offers a promising method to study anti-angiogenic drug mechanisms of action in vivo and holds potential in monitoring and guiding anti-angiogenic therapy.

Fruquintinib: a novel antivascular endothelial growth factor receptor tyrosine kinase inhibitor for the treatment of metastatic colorectal cancer

Angiogenesis plays a critical role in the neoplastic growth, progression, and metastasis of colorectal cancer (CRC) in a process regulated by vascular endothelial growth factor (VEGF) family members and their receptors (VEGFR). Several small-molecule anti-VEGFR tyrosine kinase inhibitors (TKIs), such as regorafenib, famitinib, axitinib and apatinib, have been shown to be effective in treating metastatic colorectal cancer (mCRC). Fruquintinib (ELUNATE^®) is a novel oral anti-VEGFR TKI, originated and developed by Hutchison MediPharma. Fruquintinib is a potent and highly selective small-molecule inhibitor of VEGFR-1, -2 and -3. In the Phase 3 FRESCO trial, fruquintinib improved both overall survival (OS) and progression-free survival (PFS) in patients with mCRC, compared with placebo. Fruquintinib also showed an acceptable safety and tolerability profile. Based on the data from this trial, fruquintinib was approved by the China Food and Drug Administration (CFDA) in 2018, for the treatment of patients with mCRC who had undergone at least two prior standard anticancer therapies. The existing clinical trials and future prospects of fruquintinib in mCRC will be discussed in this article. In addition, to better understand the role of fruquintinib in this setting, recent advances in other anti-VEGFR TKIs for mCRC treatment are also reviewed herein.

Novel dual inhibitors targeting CDK4 and VEGFR2 synergistically suppressed cancer progression and angiogenesis

Based on the significantly synergistic effects of CDK4 and VEGFR2 inhibitors on growth of cancer cells, a series of novel multi-kinase inhibitors targeting CDK4 and VEGFR2 were designed, synthesized and evaluated, among which Roxyl-ZV-5J exhibited potent and balanced activities against both CDK4 and VEGFR2 with half-maximal inhibitory concentration at the nanomolar level. It effectively induced breast and cervical cancer cell cycle arrest and cell apoptosis. Roxyl-ZV-5J also inhibited the proliferation, tube formation and VEGFR2 downstream signaling pathways of HUVECs. Oral administration of Roxyl-ZV-5J led to significant tumor regression and anti-angiogenesis without obvious toxicity in SiHa xenograft mouse model. In addition, this compound showed good pharmacokinetics. This study confirmed a new tool for dual CDK-VEGFR2 pathways inhibition achieved with a single molecule, which provided valuable leads for further structural optimization and anti-angiogenesis and anti-tumor mechanism study.

Epigenetics: The master control of endothelial cell fate in cancer

The development of new blood vessels from pre-existing vasculature is called angiogenesis. The growth of tumors depends on a network of supplying vessels that provide them with oxygen and nutrients. Pro-angiogenic factors that are secreted by tumors will trigger the sprouting of nearby existing blood vessels towards themselves and therefore researchers have developed targeted therapy towards these pro-angiogenic proteins to inhibit angiogenesis. However, certain pro-angiogenic proteins tend to bypass the inhibition. Thus, instead of targeting these expressed proteins, research towards angiogenesis inhibition had been focused on a deeper scale, epigenetic modifications. Epigenetic regulatory mechanisms are a heritable change in a sequence of stable but reversible gene function modification yet do not affect the DNA primary sequence directly. Methylation of DNA, modification of histone and silencing of micro-RNA (miRNA)-associated gene are currently considered to initiate and sustain epigenetic changes. Recent findings on the subject matter have provided an insight into the mechanism of epigenetic modifications, thus this review aims to present an update on the latest studies.