Lactate-modulated induction of THBS-1 activates transforming growth factor (TGF)-beta2 and migration of glioma cells in vitro.

Abstract

BACKGROUND:

An important phenomenon observed in glioma metabolism is increased aerobic glycolysis in tumor cells, which is generally referred to as the Warburg effect. Transforming growth factor (TGF)-beta2, which we previously showed to be induced by lactic acid, is a key pathophysiological factor in glioblastoma, leading to increased invasion and severe local immunosuppression after proteolytic cleavage from its latency associated peptide. In this study we tested the hypothesis, that lactate regulates TGF-beta2 expression and glioma cell migration via induction of Thrombospondin-1 (THBS-1), a TGF-beta activating protein.

METHODS:

Lactate levels were reduced by knockdown of LDH-A using specific small interfering RNA (siRNA) and competitive inhibition of LDH-A by sodium oxamate. Knockdown of THBS-1 was performed using specific siRNA. Western Blot, qRT-PCR, and ELISA were used to investigate expression levels of LDH-A, LDH-B, TGF-beta2 and THBS-1. Migration of cells was examined by Spheroid, Scratch and Boyden Chamber assays.

RESULTS:

Knockdown of LDH-A with subsequent decrease of lactate concentration leads to reduced levels of THBS-1 and TGF-beta2 in glioma cells. Lactate addition increases THBS-1 protein, leading to increased activation of TGF-beta2. Inhibition of THBS-1 reduces TGF-beta2 protein and migration of glioma cells. Addition of synthetic THBS-1 can rescue reduced TGF-beta2 protein levels and glioma cell migration in siLDH-A treated cells.

CONCLUSION:

We define a regulatory cascade between lactate, THBS-1 and TGF-beta2, leading to enhanced migration of glioma cells. Our results demonstrate a specific interaction between tumor metabolism and migration and provide a better understanding of the mechanisms underlying glioma cell invasion.

• Authors: Corinna Seliger, Petra Leukel, Sylvia Moeckel, Birgit Jachnik, Claudio Lottaz, Marina Kreutz, Alexander Brawanski, Martin Proescholdt, Ulrich Bogdahn, Anja-Katrin Bosserhoff, Arabel Vollmann-Zwerenz, Peter Hau
• Journal: PloS one (PLoS One) Vol. 8 Issue 11 Pg. e78935 ( 2013) ISSN: 1932-6203 [Electronic] United States
• PMID: 24223867 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Isoenzymes
• Thrombospondin 1
• Transforming Growth Factor beta2
• Lactic Acid
• L-Lactate Dehydrogenase
• Lactate Dehydrogenase 5

Topics

• Apoptosis (drug effects, genetics)
• Blotting, Western
• Cell Line, Tumor
• Cell Movement (drug effects, genetics)
• Cell Proliferation (drug effects)
• Enzyme-Linked Immunosorbent Assay
• Glioma (genetics, metabolism, pathology)
• Humans
• Isoenzymes (genetics, metabolism)
• L-Lactate Dehydrogenase (genetics, metabolism)
• Lactate Dehydrogenase 5
• Lactic Acid (metabolism, pharmacology)
• RNA Interference
• Reverse Transcriptase Polymerase Chain Reaction
• Thrombospondin 1 (genetics, metabolism)
• Transcriptional Activation (drug effects)
• Transforming Growth Factor beta2 (genetics, metabolism)
• Tumor Cells, Cultured