Lysine-222 succinylation reduces lysosomal degradation of lactate dehydrogenase a and is increased in gastric cancer

Abstract

Background: Lysine succinylation is an emerging posttranslational modification that has garnered increased attention recently, but its role in gastric cancer (GC) remains underexplored. Methods: Proteomic quantification of lysine succinylation was performed in human GC tissues and adjacent normal tissues by mass spectrometry. The mRNA and protein levels of lactate dehydrogenase A (LDHA) in GC and adjacent normal tissues were analyzed by qRT-PCR and western blot, respectively. The expression of K222-succinylated LDHA was measured in GC tissue microarray by the K222 succinylation-specific antibody. The interaction between LDHA and sequestosome 1 (SQSTM1) was measured by co-immunoprecipitation (co-IP) and proximity ligation assay (PLA). The binding of carnitine palmitoyltransferase 1A (CPT1A) to LDHA was determined by co-IP. The effect of K222succinylated LDHA on tumor growth and metastasis was evaluated by in vitro and in vivo experiments. Results: Altogether, 503 lysine succinylation sites in 303 proteins were identified. Lactate dehydrogenase A (LDHA), the key enzyme in Warburg effect, was found highly succinylated at K222 in GC. Intriguingly, this modification did not affect LDHA ubiquitination, but reduced the binding of ubiquitinated LDHA to SQSTM1, thereby decreasing its lysosomal degradation. We demonstrated that CPT1A functions as a lysine succinyltransferase that interacts with and succinylates LDHA. Moreover, high K222-succinylation of LDHA was associated with poor prognosis in patients with GC. Finally, overexpression of a succinylation-mimic mutant of LDHA promoted cell proliferation, invasion, and migration. Conclusions: Our data revealed a novel lysosomal pathway of LDHA degradation, which is mediated by the binding of K63-ubiquitinated LDHA to SQSTM1. Strikingly, CPT1A succinylates LDHA on K222, which thereby reduces the binding and inhibits the degradation of LDHA, as well as promotes GC invasion and proliferation. This study thus uncovers a new role of lysine succinylation and the mechanism underlying LDHA upregulation in GC.

H19 promotes aerobic glycolysis, proliferation, and immune escape of gastric cancer cells through the microRNA‐519d‐3p/lactate dehydrogenase A axis

“…Moreover, the mRNA and protein levels of LDHA were positively associated with H19 levels in GC cells. Importantly, LDHA was highly expressed in GC samples, 35,36 and involved in glucose metabolism, proliferation, and migration of GC cells. 37,38 Therefore, we inferred that H19 par- knockdown decreased PDK1 expression through the let-7/HIF-1α axis in hypoxia, and ablation of PDK1 counteracted H19-mediated glycolysis, suggesting that H19 modulated glycolysis through the let-7/HIF-1α/PDK1 axis.…”

Pathways of Non-enzymatic Lysine Acylation

“…For instance, stability of tumor suppressor p53 is increased by acetylation counteracting ubiquitylation ( Caron et al, 2005 ) and direct acetylation of ubiquitin is an inhibitor of polyubiquitylation ( Ohtake et al, 2015 ). Very recently, the inhibition of ubiquitylation by succinylation was demonstrated for lactate dehydrogenase resulting in higher cell proliferation, invasion, and migration in gastric cancer ( Li et al, 2020 ).…”

Insights into the post-translational modification and its emerging role in shaping the tumor microenvironment

“…The stability of succinylated LDHA was maintained to promote cell growth and invasion by reducing the degradation of ubiquitinated LDHA. 226 Glutamine (Gln) can be converted to α- Ketoglutarate enters the tricarboxylic acid (TCA) cycle and plays a key role in synthesizing intermediates of mitochondrial metabolism, maintaining tumor cell growth, and signal regulation. 227 The two glutaminase isoforms are liver-type (GLS2) and kidney-type (GLS), in which the site 311 of GLS is activated by succinylation to resist oxidative stress and promote tumor survival by increasing glutamine decomposition and NADPH/glutathione production.…”