Combinatorial Drug Testing in 3D Microtumors Derived from GBM Patient-Derived Xenografts Reveals Cytotoxic Synergy in Pharmacokinomics-informed Pathway Interactions

Abstract

Glioblastoma multiforme (GBM), the most common form of primary malignant brain cancer in adults, is a devastating disease for which effective treatment has remained elusive for over 75 years. One reason for the minimal progress during this time is the lack of accurate preclinical models to represent the patient’s tumor’s in vivo environment, causing a disconnect in drug therapy effectiveness between the laboratory and clinic. While patient-derived xenografts (PDX’s or xenolines) are excellent human tumor representations, they are not amenable to high throughput testing. Therefore, we developed a miniaturized xenoline system (microtumors) for drug testing. Nineteen GBM xenolines were profiled for global kinase (kinomic) activity revealing actionable kinase targets associated with intracranial tumor growth rate. Kinase inhibitors for these targets (WP1066, selumetinib, crizotinib, and cediranib) were selected for single and combination therapy using a fully human-derived three-dimensional (3D) microtumor model of GBM xenoline cells embedded in HuBiogel for subsequent molecular and phenotype assays. GBM microtumors closely resembled orthotopically-implanted tumors based on immunohistochemical analysis and displayed kinomic and morphological diversity. Drug response testing could be reproducibly performed in a 96-well format identifying several synergistic combinations. Our findings indicate that 3D microtumors can provide a suitable high-throughput model for combination drug testing.

Fibroblast growth factor receptor facilitates recurrence of minimal residual disease following trastuzumab emtansine therapy

“…Lysates from HME2 cell conditions indicated above, were analyzed on tyrosine chip (PTK) and serine–threonine chip (STK) arrays using 15 μg (PTK) or 2 μg (STK) of input material as per standard protocol in the UAB Kinome Core as previously described 23 , 33 . Three replicates of chip-paired samples were used and phosphorylation data were collected over multiple computer controlled kinetic pumping cycles, and exposure times (0, 10, 20, 50, 100, 200 ms) for each of the phosphorylatable substrates.…”

Glioblastoma’s Next Top Model: Novel Culture Systems for Brain Cancer Radiotherapy Research

“…Furthermore, a group from the University of Alabama is currently developing a microtumor 3D culture system for patient derveid samples, using a humanized matrigel alternative. Their research suggests that this model more effectively predicts kinase activity and signaling pathway status than 2D models [118]. As with matrigel, the ECM engulfing GBM tumors contain little collagen, rendering this system as a suboptimal representation of GBM tumor microenvironment.…”

A Novel Assay for Profiling GBM Cancer Model Heterogeneity and Drug Screening

“…Derivative models contain stem-like cells as evident by CD133 staining and actively proliferating cells as evident by Ki67 staining seen in Figure 2B. Gilbert et al (2018) provides more details describing spheroids and microtumors [9].…”

“…Traditionally, in vitro monolayer culture or GBM spheroids including immortalized glioma cells such as U87, have been used for drug candidate screening [5,6]. More recently, it has been shown that 3D cultures of GBM microtumors grown in a human extra-cellular matrix provide more reliable and relevant preclinical models for drug screening [7,8,9]. Three-dimensional (3D) microtumors are scalable for high-throughput assays while being a more reliable preclinical model than traditional spheroid culture by better recapitulating the characteristics of GBM seen in the patient.…”