Abstract 55: Glucose metabolism influences migration of high-grade glioma in vitro by modification of TGF-beta2

TLDR: This study demonstrates, for the first time, that knockdown of LDH-A can decrease the RNA and protein level of TSP-1 and consecutively the processing of TGF-beta2.

Abstract: Introduction: Lactate dehydrogenase type A (LDH-A) is a key metabolic enzyme catalyzing pyruvate into lactate and is excessively expressed in several human tumors. Transforming growth factor-beta2 (TGF-beta2) is a key regulator of invasion in high-grade gliomas, partially remodeling the extracellular matrix (ECM) and inducing proteinases. Thrombospondin1 (THBS-1) is an extracellular protein important for activation and processing of TGF-beta2. A microarray of LDH-A knocked-down glioma cell RNA showed down regulation of THBS-1 and TGF-beta2. In this study, we tested the hypothesis that LDH-A influences TGF-beta2 activation by up regulation of THBS-1 leading to an enhanced migration of high-grade glioma in vitro. Methods: We performed LDH-A knock-down by transient transfection of glioma cells with small interfering RNA directed against LDH-A (siLDH-A). Expression levels of TGF-beta2 and THBS-1 in siLDH-A transfected cells were investigated using microarrays, RT-PCR, Western Blot and ELISA. Migration of transfected cells was investigated by Boyden Chamber and scratch assays. Results: siLDH-A suppresses TGF-beta2 in high-grade glioma and decreases the expression of THBS-1 on the RNA and protein level. THBS-1 leads to an increased level of activated TGF-beta2 in supernatants of siLDH-A treated cells. In migration assays, siLDH-A leads to a decreased migration of high-grade glioma cells. Discussion: We demonstrate, for the first time, that knockdown of LDH-A can decrease the RNA and protein level of TSP-1 and consecutively the processing of TGF-beta2. Additionally, knockdown of LDH-A decreases the RNA level of TGF-beta2. Both results may contribute to an enhanced level of TGF-beta2 and increased migration, given that LDH-A is expressed. An increased expression of LDH-A has been found in aerobic glycolysis, a mechanism well known from several human cancers. Recent paper showed that LDH-A is able to bind RNA. Thus we suppose LDH-A could influence the level of TGF-beta2 RNA by RNA stabilization. Together with our recent results that show that TGF-beta enhances migration in high-grade gliomas, we demonstrate a new panel of interactions between lactate metabolism and TGF-beta2 that might be crucial for glioma migration and possibly invasion. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 55.