Amelioration of oxygen-induced retinopathy in neonatal mice with fetal growth restriction

Introduction: With the aim of optimizing the balance of maintaining a safe oxygen saturation and reducing the risk of retinopathy of prematurity in human neonates with fetal growth restriction (FGR), the present study investigated the distinct effects of oxygen supplementation on the retinal neovasculature using a murine premature neonatal oxygen-induced retinopathy (OIR) model with or without fetal growth restriction. Methods: For comparison with normal birth-weight neonates, maternal low-protein diet-induced FGR neonates were subjected to fluctuating oxygen levels to generate oxygen-induced retinopathy. The retinal neovasculature was histologically evaluated, and comprehensive transcriptome analysis was conducted. Results: Compared to OIR neonates with normal birth weight, significant amelioration of the neovasculature, as indicated by decreases in the number of branch junctions, vascular distribution, maximal vascular radius and microaneurysm-like tufts, was observed in OIR mice with FGR. The results of retinal RNA-sequencing revealed downregulation of angiogenic factors that trigger pathological retinal neovascularization, such as the mitogen-activated protein kinase pathway and corresponding upstream signaling pathways in OIR mice with FGR. Conclusion: Our findings demonstrated that FGR neonates have a higher capacity for retinal oxygen stress, and the risk of OIR development is attenuated compared to that in mature neonates with normal birth weight.

AB Toxins as High-Affinity Ligands for Cell Targeting in Cancer Therapy

Conventional targeted therapies for the treatment of cancer have limitations, including the development of acquired resistance. However, novel alternatives have emerged in the form of targeted therapies based on AB toxins. These biotoxins are a diverse group of highly poisonous molecules that show a nanomolar affinity for their target cell receptors, making them an invaluable source of ligands for biomedical applications. Bacterial AB toxins, in particular, are modular proteins that can be genetically engineered to develop high-affinity therapeutic compounds. These toxins consist of two distinct domains: a catalytically active domain and an innocuous domain that acts as a ligand, directing the catalytic domain to the target cells. Interestingly, many tumor cells show receptors on the surface that are recognized by AB toxins, making these high-affinity proteins promising tools for developing new methods for targeting anticancer therapies. Here we describe the structure and mechanisms of action of Diphtheria (Dtx), Anthrax (Atx), Shiga (Stx), and Cholera (Ctx) toxins, and review the potential uses of AB toxins in cancer therapy. We also discuss the main advances in this field, some successful results, and, finally, the possible development of innovative and precise applications in oncology based on engineered recombinant AB toxins.

Prostate-Specific Membrane Antigen in Anaplastic and Poorly Differentiated Thyroid Cancer-A New Diagnostic and Therapeutic Target?

Several studies have demonstrated an expression of the prostate-specific membrane antigen (PSMA) in the cancer-related neovasculature of thyroid malignancies. Due to the poor prognosis and limited therapeutic options for patients with anaplastic (ATC) and poorly differentiated (PDTC) thyroid carcinoma, the aim of our study was to investigate the theranostic approach of PSMA expression in these patients. The PSMA uptake on Gallium-68 (⁶⁸Ga)-PSMA-positron emission tomography/computed tomography (PET/CT) and glucose uptake on F-18-Fluordeoxyglucose (¹⁸F-FDG)-PET/CTs were analysed in two ATC and six PDTC patients. The PSMA expression in corresponding patients' tissue samples was detected by immunohistochemistry. In addition, various tissue sections from 22 ATC and six PDTC patients were examined concerning PSMA expression. ⁶⁸Ga-PSMA-PET/CT showed heterogeneous PSMA expression among patients and lesions. Six of the eight analyzed patients (two ATC, four PDTC) showed increased glucose metabolism without increased PSMA uptake after PET/CT. In one patient (PDTC), ¹⁸F-FDG-PET/CT tracer uptake was positive and ⁶⁸Ga-PSMA-PET/CT showed heterogeneous results. Another patient (PDTC) evidenced only PSMA-positive lesions and received two cycles of Lutetium-177 (¹⁷⁷Lu)-PSMA therapy, which kept his disease stable for seven months. There was a correlation between immunohistochemical PSMA expression and uptake on ⁶⁸Ga-PMSA-PET/CT in three of the examined patients. Twenty-seven of the analyzed 39 ATC and 13 of the analyzed 22 PDTC tissue sections showed a strong PSMA expression. Considering the rarity of PDTC and ATC, which is the reason for the small patient population we studied, the findings of this study confirm the high diagnostic sensitivity and superiority of ¹⁸F-FDG-PET/CT in comparison to ⁶⁸Ga-PSMA-PET/CT in the diagnosis of ATC and PDTC. However, it can be suggested that ⁶⁸Ga-PMSA-PET/CT can be considered as a beneficial adjunct to the well-established ¹⁸F-FDG-PET/CT for a few individual selected patients with ATC and PDTC to detect lesions not discovered by ¹⁸F-FDG-PET/CT and to determine patients' eligibility for a radioligand therapy. Radiolabelled PSMA-ligands may, in the future, represent a theranostic approach with only minor side effects for a few individual selected patients with ATC and PDTC who need alternative treatment options in case of progression when established therapies are no longer effective. However, due to the small sample size of our collective, larger studies are needed to allow for a final evaluation on the significance of PSMA-targeted diagnostic and therapy for ATC and PDTC.

Multifunctional Traceable Liposomes with Temperature-Triggered Drug Release and Neovasculature-Targeting Properties for Improved Cancer Chemotherapy

Poor distribution of nanocarriers at the tumor site and insufficient drug penetration into the tissue are major challenges in the development of effective and safe cancer therapy. Here, we aim to enhance the therapeutic effect of liposomes by accumulating doxorubicin-loaded liposomes at high concentrations in and around the tumor, followed by heat-triggered drug release to facilitate low-molecular-weight drug penetration throughout the tumor. A cyclic RGD peptide (cRGD) was incorporated into liposomes decorated with a thermosensitive polymer that allowed precise tuning of drug release temperature (i.e., Polymer-lip) to develop a targeted thermosensitive liposome (cRGD-Polymer-lip). Compared with conventional thermosensitive liposomes, cRGD-Polymer-lip enhanced the binding of liposomes to endothelial cells, leading to their accumulation at the tumor site upon intravenous administration in tumor-bearing mice. Drug release triggered by local heating strongly inhibited tumor growth. Notably, tumor remission was achieved via multiple administrations of cRGD-Polymer-lip and heat treatments. Thus, combining the advantages of tumor neovascular targeting and heat-triggered drug release, these liposomes offer high potential for minimally invasive and effective cancer chemotherapy.

Safe eradication of large established tumors using neovasculature-targeted tumor necrosis factor-based therapies

Systemic toxicities have severely limited the clinical application of tumor necrosis factor (TNF) as an anticancer agent. Activity‐on‐Target cytokines (AcTakines) are a novel class of immunocytokines with improved therapeutic index. A TNF‐based AcTakine targeted to CD13 enables selective activation of the tumor neovasculature without any detectable toxicity in vivo. Upregulation of adhesion markers supports enhanced T‐cell infiltration leading to control or elimination of solid tumors by, respectively, CAR T cells or a combination therapy with CD8‐targeted type I interferon AcTakine. Co‐treatment with a CD13‐targeted type II interferon AcTakine leads to very rapid destruction of the tumor neovasculature and complete regression of large, established tumors. As no tumor markers are needed, safe and efficacious elimination of a broad range of tumor types becomes feasible.

Enhanced Glioblastoma Targeting Ability of Carfilzomib Enabled by a DA7R-Modified Lipid Nanodisk

The robust proliferation of tumors relies on a rich neovasculature for nutrient supplies. Therefore, a basic strategy of tumor targeting therapy should include not only killing regular cancer cells but also blocking tumor neovasculature. D-peptide ^DA7R, which was previously reported to specifically bind vascular endothelial growth factor receptor 2 (VEGFR2) and neuropilin-1 (NRP-1), could achieve the goal of multitarget recognition. Accordingly, the main purposes of this work were to establish a carfilzomib-loaded lipid nanodisk modified with multifunctional peptide ^DA7R (^DA7R-ND/CFZ) and to evaluate its anti-glioblastoma efficacy in vitro and in vivo. It is testified that the ^DA7R peptide-conjugated lipid nanodisk can be specifically taken up by U87MG cells and HUVECs. Furthermore, ^DA7R-ND demonstrated a more enhanced penetration than that of the nonmodified formulation on the tumor spheroid model in vitro and more tumor region accumulation in vivo on the subcutaneous and intracranial tumor-bearing nude mice model. ^DA7R-ND was shown to co-localize with tumor neovasculature in vivo. When loaded with proteasome inhibitor carfilzomib, the ^DA7R-decorated nanodisk could remarkably suppress tumor proliferation, extend survival time of nude mice bearing an intracranial tumor, and inhibit neovasculature formation with an efficacy higher than that of the nonmodified nanodisk in vitro and in vivo. The present study verified that the heptapeptide ^DA7R-conjugated nanodisk is a promising nanocarrier for glioblastoma targeting therapy.

Expression of PSMA in tumor neovasculature of high grade sarcomas including synovial sarcoma, rhabdomyosarcoma, undifferentiated sarcoma and MPNST

AIMS

PSMA (prostate specific membrane antigen) is physiologically expressed in normal prostate tissue. It is overexpressed in prostate cancer cells and has been suggested as a target for antibody-based radioligand therapy. As PSMA expression so far has not been systematically analyzed in soft tissue tumors, the current study aims at investigating a large cohort of different subtypes.

METHODS AND RESULTS

Immunohistochemistry was used to detect PSMA expression in 779 samples of soft tissue tumors and Ewing sarcoma as a primary bone malignancy. CD34 coexpression was employed to study PSMA expression in the neovasculature. PSMA expression was found in the tumor-associated neovasculature of 151/779 soft tissue/bone tumors (19.38%) and was more frequent in malignant tumors compared to tumors with intermediate or benign biological potential (p=0.078). Strong neovascular PSMA expression was predominantly observed in subsets of different sarcomas including 3/20 rhabdomyosarcomas (15%), 4/21 malignant peripheral nerve sheath tumors (19.05%), 6/16 synovial sarcomas (35.29%) and 6/33 undifferentiated pleomorphic sarcomas (18.18%).

CONCLUSION

We conclude that PSMA is expressed in the neovasculature of a subset of soft tissue tumors to a variable extent. Our observation of strong PSMA expression predominantly occurring in sarcomas might provide a rationale to evaluate PSMA-targeted radioligand therapy in these entities.

RGD and interleukin-13 peptide functionalized nanoparticles for enhanced glioblastoma cells and neovasculature dual targeting delivery and elevated tumor penetration

As the most common malignant brain tumors, glioblastoma multiforme (GBM) was characterized by angiogenesis and tumor cells proliferation. Dual targeting to neovasculature and GBM cells could deliver cargoes to these two kinds of cells, leading to a combination treatment. In this study, polymeric nanoparticles were functionalized with RGD and interleukin-13 peptide (IRNPs) to construct a neovasculature and tumor cell dual targeting delivery system in which RGD could target αvβ3 on neovasculature and interleukin-13 peptide could target IL13Rα2 on GBM cells. In vitro, interleukin-13 peptide and RGD could enhance the uptake by corresponding cells (C6 and human umbilical vein endothelial cells). Due to the expression of both receptors on C6 cells, RGD also could enhance the uptake by C6 cells. Through receptor labeling, it clearly showed that αvβ3 could mediate the internalization of RGD modified nanoparticles and IL13Rα2 could mediate the internalization of interleukin-13 peptide modified nanoparticles. The ligand functionalization also resulted in a modification on endocytosis pathways, which changed the main endocytosis pathways from macropinocytosis for unmodified nanoparticles to clathrin-mediated endocytosis for IRNPs. IRNPs also displayed the strongest penetration ability according to tumor spheroid analysis. In vivo, IRNPs could effectively deliver cargoes to GBM with higher intensity than monomodified nanoparticles. After CD31-staining, it demonstrated IRNPs could target both neovasculature and GBM cells. In conclusion, IRNPs showed promising ability in dual targeting both neovasculature and GBM cells.

Molecular targeting of liposomal nanoparticles to tumor microenvironment

Liposomes are biodegradable and can be used to deliver drugs at a much higher concentration in tumor tissues than in normal tissues. Both passive and active drug delivery by liposomal nanoparticles can significantly reduce the toxic side effects of anticancer drugs and enhance the therapeutic efficacy of the drugs delivered. Active liposomal targeting to tumors is achieved by recognizing specific tumor receptors through tumor-specific ligands or antibodies coupled onto the surface of the liposomes, or by stimulus-sensitive drug carriers such as acid-triggered release or enzyme-triggered drug release. Tumors are often composed of tumor cells and nontumor cells, which include endothelial cells, pericytes, fibroblasts, stromal, mesenchymal cells, innate, and adaptive immune cells. These nontumor cells thus form the tumor microenvironment, which could be targeted and modified so that it is unfavorable for tumor cells to grow. In this review, we briefly summarized articles that had taken advantage of liposomal nanoparticles as a carrier to deliver anticancer drugs to the tumor microenvironment, and how they overcame obstacles such as nonspecific uptake, interaction with components in blood, and toxicity. Special attention is devoted to the liposomal targeting of anticancer drugs to the endothelium of tumor neovasculature, tumor associated macrophages, fibroblasts, and pericytes within the tumor microenvironment.

Upregulation of pleiotrophin gene expression in developing microvasculature, macrophages, and astrocytes after acute ischemic brain injury

Pleiotrophin (PTN) is a heparin-binding, 18 kDa secretory protein that functions to induce mitogenesis, angiogenesis, differentiation, and transformation in vitro. PTN gene (Ptn) expression is highly regulated during development and is highest at sites in which mitogenesis, angiogenesis, and differentiation are active. In striking contrast, with the exception of the neuron, the Ptn gene is only minimally expressed in adults. We now demonstrate that Ptn gene expression is strikingly upregulated within 3 d in OX42-positive macrophages, astrocytes, and endothelial cells in areas of developing neovasculature after focal cerebral ischemia in adult rat. Ptn gene expression remains upregulated in these same cells and sites 7 and 14 d after ischemic injury. However, expression of the Ptn gene is significantly decreased in cortical neurons 6 and 24 hr after injury and is undetectable in degenerating neurons at day 3. Neurons in contralateral cortex continue to express Ptn in levels equal to control, uninjured brain. It is suggested that PTN may have a vital role in neovascular formation in postischemic brain and that postischemic brain is an important model in which to analyze sequential gene expression in developing neovasculature. In contrast, Ptn gene expression in injured neurons destined not to recover is strikingly reduced, and potentially its absence may contribute to the failure of the neuron to survive.