The development of a rapid patient-derived xenograft model to predict chemotherapeutic drug sensitivity/resistance in malignant glial tumors

BACKGROUND

High-grade gliomas (HGG) are aggressive brain tumors associated with short median patient survival and limited response to therapies, driving the need to develop tools to improve patient outcomes. Patient-derived xenograft (PDX) models, such as mouse PDX, have emerged as potential Avatar platforms for personalized oncology approaches, but the difficulty for some human grafts to grow successfully and the long time required for mice to develop tumors preclude their use for HGG.

METHODS

We used a rapid and efficient ex-ovo chicken embryo chorioallantoic membrane (CAM) culture system to evaluate the efficacy of oncologic drug options for HGG patients.

RESULTS

Implantation of fresh glioma tissue fragments from 59 of 60 patients, that include difficult-to-grow IDH-mutated samples, successfully established CAM tumor xenografts within 7 days, with a tumor take rate of 98.3%. These xenografts faithfully recapitulate the histological and molecular characteristics of the primary tumor, and the ability of individual fragments to form tumors was predictive of poor patient prognosis. Treatment of drug-sensitive or drug-resistant xenografts indicates that the CAM-glioma assay enables testing tumor sensitivity to temozolomide and carboplatin at doses consistent with those administered to patients. In a proof-of-concept study involving 14 HGG patients, we observed a correlation of 100% between the CAM xenograft response to temozolomide or carboplatin and the clinical response of patients.

CONCLUSION

The CAM-glioma model is a fast and reliable assay that has the potential to serve as a complementary model to drug discovery and a real-time Avatar platform to predict the best treatment for HGG patients.

Antiangiogenic activity of zinc and zinc-sorafenib combination using the chick chorioallantoic membrane assay: A descriptive study

Aim

Zinc, a trace element, is known for downregulating several proangiogenic growth factors and cytokines. However, its antiangiogenic activity is not adequately studied. The present study was aimed to evaluate the possible antiangiogenic activity of zinc via the chick chorioallantoic membrane (CAM) assay. Furthermore, the antiangiogenic activity of the combination therapy of zinc with various doses of sorafenib, a tyrosine kinase inhibitor, was evaluated.

Materials and Methods

A pilot study was initially conducted so as to select suitable doses of zinc and sorafenib. The antiangiogenic activity after combining zinc 2.5 μg/embryo with sorafenib 1 and 2 μg/embryo was also evaluated. The antiangiogenic activity was quantified in terms of total length of blood vessels, number of junctions, number of branching points, and mean length of the blood vessels.

Results

Zinc 2.5 μg/embryo showed significant (P < 0.05) antiangiogenic activity, as compared to the control group. However, its effect was not comparable to that of sorafenib 2 μg/embryo. The combination of zinc 2.5 μg/embryo with sorafenib 2 μg/embryo did not show an additive/synergistic effect. The combination of zinc 2.5 μg/embryo with sorafenib 1 μg/embryo produced an antiangiogenic activity which was comparable (P > 0.05) to that of sorafenib 2 μg/embryo.

Conclusion

Zinc caused significant antiangiogenic activity in the CAM assay. The lack of addition/synergism in the zinc-sorafenib combination could have been due to the variability in the dose/ratio selection. Addition of zinc to sorafenib therapy could improve treatment tolerability, reduce cost of therapy, and reduce the emergence of drug resistance. Future mechanistic studies could identify the exact pharmacodynamics of zinc as an angiogenesis inhibitor.

Evaluation of antiangiogenic and antiproliferative potential of ethanolic extracts of Andrographis echioides using in vitro and in ovo assays

Introduction

Andrographis echioides is a prevalently used medicinal herb in South Asian countries. Scientific researches with the extracts of A. echioides revealed its antipyretic, anti-inflammatory, antimicrobial, ulceroprotective, and hepatoprotective properties. This study was done to elucidate antiproliferative and antiangiogenic potential of ethanolic extracts of A. echioides (EEAE) by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and chorioallantoic membrane (CAM) assay.

Materials and Methods

EEAE was prepared using Soxhlet apparatus with ethanol after being sun-dried and powdered. MCF 7 (human invasive breast ductal carcinoma) cell lines retaining attributes of differentiated mammary epithelium with both estrogen and progesterone receptors were treated with EEAE, and antiproliferative effect was seen using Mosmann method of MTT assay using 5-fluorouracil (5-FU) as a comparator. The evaluation of antiangiogenic potential of EEAE was done by comparing mean vessel density (MVD) in chick CAM after treatment with EEAE, thalidomide, and vascular endothelial growth factor (VEGF) using CAM assay, an in ovo assay.

Results

EEAE displayed antiproliferative activity from low to high concentrations with MTT assay. The IC₅₀ of EEAE and 5-FU was 62.5 and 15.6 μg/ml, respectively (P < 0.05). The exhibition of its antiangiogenic activity increased proportionately with increasing concentration. VEGF increased MVD by 45.94%; thalidomide decreased it by 53.76%. There was a decrease of MVD by 5.91%, 20.46%, and 35.95% at concentrations of 25, 50, and 100 μg of EEAE, respectively.

Conclusion

EEAE possessed significant antiangiogenic and antiproliferative activity, making them a promising substrate in the development of a novel anticancer drug and can be successfully used in the therapy of various cancers after establishment of the anticancer effects in animal models and subsequently in clinical trials.

Chrysosplenol d, a Flavonol from Artemisia annua, Induces ERK1/2-Mediated Apoptosis in Triple Negative Human Breast Cancer Cells

Triple negative human breast cancer (TNBC) is an aggressive cancer subtype with poor prognosis. Besides the better-known artemisinin, Artemisia annua L. contains numerous active compounds not well-studied yet. High-performance liquid chromatography coupled with diode-array and mass spectrometric detection (HPLC-DAD-MS) was used for the analysis of the most abundant compounds of an Artemisia annua extract exhibiting toxicity to MDA-MB-231 TNBC cells. Artemisinin, 6,7-dimethoxycoumarin, arteannuic acid were not toxic to any of the cancer cell lines tested. The flavonols chrysosplenol d and casticin selectively inhibited the viability of the TNBC cell lines, MDA-MB-231, CAL-51, CAL-148, as well as MCF7, A549, MIA PaCa-2, and PC-3. PC-3 prostate cancer cells exhibiting high basal protein kinase B (AKT) and no ERK1/2 activation were relatively resistant, whereas MDA-MB-231 cells with high basal ERK1/2 and low AKT activity were more sensitive to chrysosplenol d treatment. In vivo, chrysosplenol d and casticin inhibited MDA-MB-231 tumor growth on chick chorioallantoic membranes. Both compounds induced mitochondrial membrane potential loss and apoptosis. Chrysosplenol d activated ERK1/2, but not other kinases tested, increased cytosolic reactive oxygen species (ROS) and induced autophagy in MDA-MB-231 cells. Lysosomal aberrations and toxicity could be antagonized by ERK1/2 inhibition. The Artemisia annua flavonols chrysosplenol d and casticin merit exploration as potential anticancer therapeutics.

A Naturally Derived Carrier for Photodynamic Treatment of Squamous Cell Carcinoma: In Vitro and In Vivo Models

Photodynamic therapy (PDT) is a non-invasive treatment strategy that includes the combination of three components-a photosensitizer, a light source, and tissue oxygen. PDT can be used for the treatment of skin diseases such as squamous cell carcinoma. The photosensitizer used in this study is the naturally derived chlorophyll derivative chlorin e6 (Ce6), which was encapsulated in ultradeformable ethosomes. Singlet oxygen production by Ce6 upon laser light irradiation was not significantly affected by encapsulation into ethosomes. PDT of squamous cell carcinoma cells treated with Ce6 ethosomes triggered increased mitochondrial superoxide levels and increased caspase 3/7 activity, resulting in concentration- and light-dose-dependent cytotoxicity. Ce6 ethosomes showed good penetration into 3D squamous cell carcinoma spheroids, which upon laser light irradiation exhibited reduced size, proliferation, and viability. The PDT effect of Ce6 ethosomes was specific and showed higher cytotoxicity against squamous cell carcinoma spheroids compared to normal skin fibroblast spheroids. In addition, PDT treatment of squamous cell carcinoma xenografts grown on chorioallantoic membranes of chick eggs (CAM) exhibited reduced expression of Ki-67 proliferation marker and increased terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining, indicating reduced proliferation and activation of apoptosis, respectively. The results demonstrate that Ce6-loaded ethosomes represent a convenient formulation for photodynamic treatment of squamous cell carcinoma.

Anti-Angiogenic Activity of Flunarizine by In Ovo, In Vitro, and In Vivo Assays

Objectives

The involvement of T-type calcium channels in cell proliferation and the role of sodium channels in cell migration have been extensively studied in angiogenesis. In the present study, flunarizine, a dual sodium/calcium channel blocker; was selected to evaluate its anti-angiogenic potential. This can be therapeutically beneficial in diseases caused by pathologically excessive angiogenesis.

Materials and Methods

The anti-angiogenic activity of ion channel blocker was screened by chick chorioallantoic membrane assay (in ovo), rat aortic ring assay, endothelial cell proliferation assay, transwell migration assay, Matrigel cord-like morphogenesis assay (in vitro), and sponge implantation method (in vivo). The anti-angiogenic activity of the test drug was compared with the standard anti-angiogenic drug bevacizumab and, in addition, the test responses were compared with the angiogenic factor vascular endothelial growth factor at a maximal concentration of 500 pM.

Results

All the groups were compared with the control group using one-way ANOVA, followed by a post hoc test, Dunnett's test, to compare the mean of all the groups with the control mean. In the chick chorioallantoic membrane assay, the number of branching points and angiogenic score were evaluated and significant results were observed at 10^-5 M and 10^-4 M. In the aortic ring assay a reduction in the area of sprouts was observed with 5-10 μM and significant reductions in the weight of sponges, number of blood vessels formed, and hemoglobin content were observed at all three tested concentrations of flunarizine in the sponge implantation method. In the studies on human umbilical vein endothelial cells the test drug (1-100 nM) showed significant inhibition of proliferation and migration and a decrease in the network length of cord-like tubes in a dose-dependent manner.

Conclusion

Flunarizine has significant anti-angiogenic action by inhibiting cell proliferation, migration, and cord-like tube formation, which resulted from blocking of the T-type calcium and sodium channels. Further studies on the structural modifications of flunarizine for repurposing this ion channel modulator will lead to treatment of the diseases due to excessive angiogenesis from the root cause.

A Novel Polyhalogenated Monoterpene Induces Cell Cycle Arrest and Apoptosis in Breast Cancer Cells

Breast cancer is the most common cancer type and a primary cause of cancer mortality among females worldwide. Here, we analyzed the anticancer efficacy of a novel bromochlorinated monoterpene, PPM1, a synthetic analogue of polyhalogenated monoterpenes from Plocamium red algae and structurally similar non-brominated monoterpenes. PPM1, but not the non-brominated monoterpenes, decreased selectively the viability of several triple-negative as well as triple-positive breast cancer cells with different p53 status without significantly affecting normal breast epithelial cells. PPM1 induced accumulation of triple-negative MDA-MB-231 cells with 4N DNA content characterized by decreased histone H3-S10/T3 phosphorylation indicating cell cycle arrest in the G₂ phase. Western immunoblot analysis revealed that PPM1 treatment triggered an initial rapid activation of Aurora kinases A/B/C and p21^Waf1/Cip1 accumulation, which was followed by accumulation of polyploid >4N cells. Flow cytometric analysis showed mitochondrial potential disruption, caspase 3/7 activation, phosphatidylserine externalization, reduction of the amount polyploid cells, and DNA fragmentation consistent with induction of apoptosis. Cell viability was partially restored by the pan-caspase inhibitor Z-VAD-FMK indicating caspase contribution. In vivo, PPM1 inhibited growth, proliferation, and induced apoptosis in MDA-MB-231 xenografted onto the chick chorioallantoic membrane. Hence, Plocamium polyhalogenated monoterpenes and synthetic analogues deserve further exploration as promising anticancer lead compounds.

Exploration of 2-deoxy-D-ribose and 17β-Estradiol as alternatives to exogenous VEGF to promote angiogenesis in tissue-engineered constructs

Aim: In this study, we explored the angiogenic potential and proangiogenic concentration ranges of 2-deoxy-D-ribose (2dDR) and 17β-Estradiol (E2) in comparison with VEGF. The 2dDR and E2 were then loaded into tissue engineering (TE) scaffolds to investigate their proangiogenic potential when released from fibers. Materials & methods: Ex ovo chick chorioallantoic membrane (CAM) assay was used to evaluate angiogenic activity of 2dDR and E2. Both factors were then introduced into scaffolds via electrospinning to assess their angiogenic potential when released from fibers. Results: Both factors were approximately 80% as potent as VEGF and showed a dose-dependent angiogenic response. The sustained release of both agents from the scaffolds stimulated neovascularization over 7 days in the chorioallantoic membrane assay. Conclusion: We conclude that both 2dDR and E2 provide attractive alternatives to VEGF for the functionalization of tissue engineering scaffolds to promote angiogenesis in vivo.

Alginate hydrogels of varied molecular weight distribution enable sustained release of sphingosine-1-phosphate and promote angiogenesis

Alginate hydrogels have been widely validated for controlled release of growth factors and cytokines, but studies exploring sustained release of small hydrophobic lipids are lacking. Sphingosine-1-phosphate (S1P), a bioactive lipid, is an appealing small molecule for inducing blood vessel formation in the context of ischemic conditions. However, there are numerous biological and engineering challenges associated with designing biomaterial systems for controlled release of this lipid. Thus, the objective of this study was to design an injectable, alginate hydrogel formulation that provides controlled release of S1P to establish locally sustained concentration gradients that promote neovascularization. Herein, we varied the molecular weight distribution of alginate polymers within the hydrogel to alter the resultant mechanical properties in a manner that provides control over S1P release. With increasing high molecular weight (HMW) content, the hydrogels exhibited stiffer material properties and released S1P at slower rates. Accordingly, S1P released from hydrogels with 100% HMW content led to enhanced directed migration of outgrowth endothelial cells and blood vessel development assessed using a chick chorioallantoic membrane assay as compared to hydrogels with less HMW content. Overall, this study describes how alginate hydrogels of varied molecular weight may be used to control S1P release kinetics for therapeutic applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 138-146, 2018.

The Role of Neutrophilic Inflammation, Angiotropism, and Pericytic Mimicry in Melanoma Progression and Metastasis

Angiotropism in melanoma correlates with ulceration and poor prognosis. It has been shown to be a marker of pericytic mimicry, that is, the spreading of tumor cells in a pericyte location along abluminal vascular surfaces. Such extravascular tumor spread may represent another form of tumor plasticity with reversion to a neural crest cell migratory phenotype. In a murine melanoma model, it has recently been demonstrated that neutrophilic skin inflammation promotes angiotropism and metastatic spread of primary melanomas. This review discusses the role of neutrophilic inflammation in angiotropism and pericytic mimicry in melanoma progression, metastasis, tumor cell plasticity, and tumor therapeutic resistance.