Novel Multitarget ACE Inhibitory Peptides from Bovine Colostrum Immunoglobulin G: Cellular Transport, Efficacy in Regulating Endothelial Dysfunction, and Network Pharmacology Studies.

In this study, we used traditional laboratory methods, bioinformatics, and cellular models to screen novel ACE inhibitory (ACEI) peptides with strong ACEI activity, moderate absorption rates, and multiple targets from bovine colostrum immunoglobulin G (IgG). The purified fraction of the compound proteinase hydrolysate of IgG showed good ACEI activity. After nano-UPLC-MS/MS identification and in silico analysis, eight peptides were synthesized and verified. Among them, SFYPDY, TSFYPDY, FSWF, WYQQVPGSGL, and GVHTFP were identified as ACEI peptides, as they exhibited strong ACEI activity (with IC50 values of 104.7, 80.0, 121.2, 39.8, and 86.3 µM, respectively). They displayed good stability in an in vitro simulated gastrointestinal digestion assay. In a Caco-2 monolayer model, SFYPDY, FSWF, and WYQQVPGSGL exhibited better absorption rates and lower IC50 values than the other peptides and were thereby identified as novel ACEI peptides. Subsequently, in a H2O2-induced endothelial dysfunction (ED) model based on HUVECs, SFYPDY, FSWF, and WYQQVPGSGL regulated ED by reducing apoptosis and ROS accumulation while upregulating NOS3 mRNA expression. Network pharmacology analysis and RT-qPCR confirmed that they regulated multiple targets. Overall, our results suggest that SFYPDY, FSWF, and WYQQVPGSGL can serve as novel multitarget ACEI peptides.

Oct4 Regulates the Transition of Cancer Stem-Like Cells to Tumor Endothelial-Like Cells in Human Liver Cancer.

Octamer-binding transcription factor 4 (Oct4) has been recently implicated as a proangiogenic regulator in several induced pluripotent stem cells (iPSCs), however, its role in cancer stem-like cells (CSCs) remain unclear. We report here that Oct4 participates in tumor vasculogenesis in liver CSCs (LCSCs). We identify that LCSCs possess the potential of endothelial trans-differentiation under endothelial induction, present endothelial specific markers and their functions in vitro, and participate in neovasculogenesis in vivo. The knockdown of the Oct4A by short hairpin RNA (shRNA) in LCSCs represses endothelial trans-differentiation potential, but induces endothelial lineage-restricted differentiation, the latter is positively regulated by Oct4B1. Furthermore, Oct4 regulates vasculogenesis in LCSCs may be via the AKT-NF-κB-p65 signaling pathway. This work reveals Oct4, which is a crucial regulator, plays a critical role in tumor endothelial-like cells transition of LCSCs through Oct4A and Oct4B1 by different ways. The simultaneous inhibition of both the isoforms of Oct4 is hence expected to help regress neovascularization derived from CSCs. Our findings may provide insights to the possible new mechanisms of tumor vasculogenesis for primary liver cancer.

Quantitative analysis for the differences in vasculogenic activity and sensitivity to angiogenic stimulants between human glioma cells and normal endothelial cells.

Neovascularization is a histological feature of glioma, especially of glioblastoma (GBM), being associated with tumor invasiveness and poor prognosis. However, current anti-angiogenic therapies targeting vascular endothelial cells (ECs), has exhibited poor efficacy in some GBM cases. This may be at least partially attributed to the potential of glioblastoma cells to construct blood supply chain via vasculogenic mimicry or endothelial differentiation. This study aims to explore differences in vasculogenic activity and sensitivity to angiogenic stimulants between normal human ECs and glioma cells of different grades. We found that grade IV U87 GBM cells showed highly inducible vasculogenic activity either in the orthotopic xenograft model or under in vitro angiogenic stimulants as compared with grade II CHG5 glioma cells. The hypoxia mimetic more strongly induced in vitro vasculogenic capacity and endothelial marker expression of U87 GBM cells than the stimulation with multiple proangiogenic growth factors (vascular endothelial growth factor, basic fibroblast growth factor and epidermal growth factor). In contrast, proangiogenic effect of hypoxia on human umbilical vein endothelial cells (HUVECs) was weaker than on U87 GBM cells. In addition, it was also observed that the in vitro vasculogenic process of U87 cells started later but lasted longer than that of HUVECs. These results demonstrate that when compared with normal ECs, high-grade glioma cells basically possess weaker vasculogenic activity, but exhibit higher sensitivity and longer-lasting response to angiogenic stimulants, especially to hypoxia. This may be helpful to develop novel anti-angiogenic strategies targeting both vascular ECs and vasculogenic glioma cells.

Expressions of glia maturation factor-ß by tumor cells and endothelia correlate with neovascularization and poor prognosis in human glioma.

Glia maturation factor-ß (GMF-ß) has been reported to promote glial differentiation, and act as a negative prognostic indicator in certain cancers. However, its roles in glioma progression remain unclear. Since neurogenesis and vasculogenesis were proved to share some common regulators during gliomagenesis, we aim to explore the potential impact of GMF-ß on tumor neovascularization and patient survival in glioma. In this study, we first detected GMF-ß expression not only in tumor cells but also in microvascular endothelia by double immunohistochemical staining. Both tumoral and endothelial GMF-ß expression levels were positively correlated with tumor grade and microvessel density (MVD), while negatively associated with poor prognoses of the patients. Interestingly, multivariate analysis demonstrated that endothelial GMF-ß expression level was the only independent predictor of progression-free and overall survival of glioma patients. The results of in vitro angiogenesis assay showed that GMF-ß knockdown significantly inhibited tubulogenesis of human U87 glioblastoma cells. Furthermore, GMF-ß knockdown suppressed tumor growth and the formation of human-CD31 positive (glioma cell-derived) microvessels in a mouse orthotopic U87 glioma model. Our results demonstrated that GMF-ß is an important player in glioma progression via promoting neovascularization. GMF-ß may therefore be a novel prognostic marker as well as a potential therapeutic target for glioma.

Hydrothermal synthesis of core-shell structured TbPO4:Ce(3+)@TbPO4:Gd(3+) nanocomposites for magnetic resonance and optical imaging.

Multi-modal imaging based on multifunctional nanoparticles provides deep, non-invasive and highly sensitive imaging and is a promising alternative approach that can improve the sensitivity of early cancer diagnosis. In this study, two nanoparticles, TbPO4:Ce(3+) and TbPO4:Ce(3+)@TbPO4:Gd(3+), were synthesized via the citric-acid-mediated hydrothermal route, and then systematically characterized by means of microstructure, photoluminescence, magnetic resonance imaging (MRI), biocompatibility, and bioimaging. The results of energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) line scans indicated that TbPO4:Gd(3+) nanoshells about 5 nm in thickness were successfully coated on the TbPO4:Ce(3+) nanocores. X-ray diffraction (XRD) and Fourier transforms of high-resolution transmission electron microscopy (TEM) images indicated that the core-shell nanocomposites had a single crystal structure. The photoluminescence of the TbPO4:Ce(3+)@TbPO4:Gd(3+) and TbPO4:Ce(3+) nanoparticles was greatly intensified by 200 times and 100 times, respectively, compared with pure TbPO4 nanoparticles. In vitro cytotoxicity tests based on the methyl thiazolyl tetrazolium (MTT) assay demonstrated that the monodispersed nanoparticles of TbPO4:Ce(3+)@TbPO4:Gd(3+) had low toxicity. The intracellular luminescence of the nanoparticles after being internalized by HeLa cells was also observed using confocal fluorescence microscopes. MRI showed that the nanoshells of Gd-doped TbPO4 possessed a longitudinal relaxivity of 4.067 s(-1) mM(-1), which is comparable to that of the commercial MRI contrast Gd-TDPA. As a result, the core-shell structured TbPO4:Ce(3+)@TbPO4:Gd(3+) nanoparticles can potentially serve as multifunctional nanoprobes for both optical biolabels and MRI contrast agents.