An Algorithm for the Preclinical Screening of Anticancer Drugs Effective against Brain Tumors

Development and evaluation of a multicomponent bioink consisting of alginate, gelatin, diethylaminoethyl cellulose and collagen peptide for 3D bioprinting of tissue construct for drug screening application

Three dimensional (3D) bioprinting technology has been making a progressive advancement in the field of tissue engineering to produce tissue constructs that mimic the shape, framework, and microenvironment of an organ. The technology has not only paved the way to organ development but has been widely studied for its application in drug and cosmetic testing using 3D bioprinted constructs. However, not much has been explored on the utilization of bioprinting technology for the development of tumor models to test anti-cancer drug efficacy. The conventional methodology involves a two dimensional (2D) monolayer model to test cellular drug response which has multiple limitations owing to its inability to mimic the natural tissue environment. The choice of bioink for 3D bioprinting is critical as cell morphology and proliferation depend greatly on the property of bioink. In this study, we developed a multicomponent bioink composed of alginate, diethylaminoethyl cellulose, gelatin, and collagen peptide to generate a 3D bioprinted construct. The bioink has been characterised and validated for its printability, shape fidelity and biocompatibility to be used for generating tumor models. Further, a bioprinted tumor model was developed using lung cancer cell line and the efficacy of 3D printed construct for drug screening application was established.

Translational gap in ongoing clinical trials for glioma

Despite the vast amounts of information gathered about gliomas, the overall survival of glioma patients has not improved in the last four decades. This could partially be due to an apparent failure to include basic concepts of glioma biology into clinical trials. Specifically, attempts to overcome the limitations of the blood brain barrier (BBB) and the chemoresistance of glioma stem cells (GSCs) were seldom included (a phenomenon known as the translational gap, TG) in a study involving 29 Phase I/II clinical trials (P2CT) published in 2011. The aim of this study was to re-evaluate this finding with a new series of 100 ongoing, but still unpublished, P2CT in order to determine if there is a TG reduction. As indicators, we evaluated in each P2CT the number of drugs tested, concomitant radiotherapy, and the ability of drugs to pass the BBB and to target GSCs. Compared to clinical trials published in 2011, we found that while in OCT there is an increase in the number of P2CT using two drugs (from 24.1% to 44.9%), and an increase in the number of drugs able to pass the BBB (7.14% versus 64.29%) and target GSCs (0% versus 16.3%), there was a decrease in the number of P2CT using concomitant radiotherapy (34.5% versus 18.37%). Overall our results suggest that there is only a modest improvement regarding reducing the TG because the vast majority of ongoing P2CT are still not including well known concepts of glioma biology important for a successful treatment.

Orthotopic Implantation and Peripheral Immune Cell Monitoring in the II-45 Syngeneic Rat Mesothelioma Model

The enormous upsurge of interest in immune-based treatments for cancer such as vaccines and immune checkpoint inhibitors, and increased understanding of the role of the tumor microenvironment in treatment response, collectively point to the need for immune-competent orthotopic models for pre-clinical testing of these new therapies. This paper demonstrates how to establish an orthotopic immune-competent rat model of pleural malignant mesothelioma. Monitoring disease progression in orthotopic models is confounded by the internal location of the tumors. To longitudinally monitor disease progression and its effect on circulating immune cells in this and other rat models of cancer, a single tube flow cytometry assay requiring only 25 µl whole blood is described. This provides accurate quantification of seven immune parameters: total lymphocytes, monocytes and neutrophils, as well as the T-cell subsets CD4 and CD8, B-cells and Natural Killer cells. Different subsets of these parameters are useful in different circumstances and models, with the neutrophil to lymphocyte ratio having the greatest utility for monitoring disease progression in the mesothelioma model. Analyzing circulating immune cell levels using this single tube method may also assist in monitoring the response to immune-based treatments and understanding the underlying mechanisms leading to success or failure of treatment.

Establishing a panel of chemo-resistant mesothelioma models for investigating chemo-resistance and identifying new treatments for mesothelioma

Mesothelioma is inherently chemo-resistant with only 50% of patients responding to the standard of care treatments, and consequently it has a very grim prognosis. The aim of this study was to establish a panel of chemo-resistant mesothelioma models with clinically relevant levels of resistance as tools for investigating chemo-resistance and identifying new treatments for mesothelioma. Chemo-resistant cell lines were established in vitro and characterized in vivo using syngeneic Fischer rats. Tumors derived from all chemo-resistant cell lines were immunohistochemically classified as mesothelioma. Homozygous deletion of p16^INK4A/p14^ARF and increased expression of several ATP-binding cassette transporters were demonstrated, consistent with findings in human mesothelioma. Further, the acquisition of chemo-resistance in vitro resulted in changes to tumor morphology and overall survival. In conclusion, these models display many features corresponding with the human disease, and provide the first series of matched parental and chemo-resistant models for in vitro and in vivo mesothelioma studies.