Treatment with Cyclic AMP Activators Reduces Glioblastoma Growth and Invasion as Assessed by Two-Photon Microscopy.

Krista Minéia Wartchow,Andreas Stadlbauer,Carlos-Alberto Gonçalves,Philipp Tripal,Andrea Kleindienst,Michael Buchfelder,Benjamin Schmid

doi:10.3390/cells10030556

Krista Minéia Wartchow, Andreas Stadlbauer + Show 5 more

Open Access

https://doi.org/10.3390/cells10030556

Copy DOI

Abstract

(1) Background: Despite progress in surgery and radio-chemotherapy of glioblastoma (GB), the prognosis remains very poor. GB cells exhibit a preference for hypoxia to maintain their tumor-forming capacity. Enhancing oxidative phosphorylation—known as the anti-Warburg effect—with cyclic AMP activators has been demonstrated to drive GB cells from proliferation to differentiation thereby reducing tumor growth in a cell culture approach. Here we re-evaluate this treatment in a more clinically relevant model. (2) Methods: The effect of treatment with dibutyryl cyclic AMP (dbcAMP, 1 mM) and the cAMP activator forskolin (50µM) was assessed in a GB cell line (U87GFP+, 104 cells) co-cultured with mouse organotypic brain slices providing architecture and biochemical properties of normal brain tissue. Cell viability was determined by propidium-iodide, and gross metabolic effects were excluded in the extracellular medium. Tumor growth was quantified in terms of area, volume, and invasion at the start of culture, 48 h, 7 days, and 14 days after treatment. (3) Results: The tumor area was significantly reduced following dbcAMP or forskolin treatment (F2,249 = 5.968, p = 0.0029). 3D volumetric quantification utilizing two-photon fluorescence microscopy revealed that the treated tumors maintained a spheric shape while the untreated controls exhibited the GB typical invasive growth pattern. (4) Conclusions: Our data demonstrate that treatment with a cAMP analog/activator reduces GB growth and invasion.

Highlights

Glioblastoma (GB) has the highest prevalence and mortality among primary brain tumors [1], and treatment options consisting of surgery, radiotherapy, and chemotherapy have not substantially improved the poor prognosis [2,3]
To exclude any effect by the drug solvent dimethyl sulfoxide (DMSO) at a concentration of 0.5%, another set of experimental control was performed with phosphate-buffered saline (PBS)
Metabolic Effects on the Glioblastoma Cell Line U87 Co-Cultured with Organotypic Brain Slices

Summary

Introduction

Glioblastoma (GB) has the highest prevalence and mortality among primary brain tumors [1], and treatment options consisting of surgery, radiotherapy, and chemotherapy have not substantially improved the poor prognosis [2,3]. The Warburg effect describes the preference of cancer cells for glycolysis, even if the capacity for mitochondrial oxidative phosphorylation (OXPHOS) exists [4]. This effect was long misinterpreted as evidence for damage to respiration, but it is recognized as a driving force in tumorigenesis [5]. While OXPHOS allows the generation of up to 36 mol ATP per mol glucose, glycolysis results just in 2 mol ATP on the benefit of 6 carbon molecules ready to enter cell replication essential for tumor proliferation [6]

Methods

Results

Discussion

Conclusion