P53-Independent Effects of Set7/9 Lysine Methyltransferase on Metabolism of Non-Small Cell Lung Cancer Cells.

Alexandra Daks,Alexander Khudiakov,Oleg Shuvalov,Olga Fedorova,Larissa Lezina,Alexey Petukhov,Ekaterina Baidyuk,Arsenia Zharova,Nickolai A Barlev

doi:10.3389/fonc.2021.706668

Abstract

Set7/9 is a lysine-specific methyltransferase, which regulates the functioning of both the histone and non-histone substrates, thereby significantly affecting the global gene expression landscape. Using microarray expression profiling, we have identified several key master regulators of metabolic networks, including c-Myc, that were affected by Set7/9 status. Consistent with this observation, c-Myc transcriptional targets—genes encoding the glycolytic enzymes hexokinase (HK2), aldolase (ALDOB), and lactate dehydrogenase (LDHA)—were upregulated upon Set7/9 knockdown (Set7/9KD). Importantly, we showed the short hairpin RNA (shRNA)-mediated attenuation of Set7/9 augmented c-Myc, GLUT1, HK2, ALDOA, and LDHA expression in non-small cell lung cancer (NSCLC) cell lines, not only at the transcriptional but also at the protein level. In line with this observation, Set7/9KD significantly augmented the membrane mitochondrial potential (MMP), glycolysis, respiration, and the proliferation rate of NSCLC cells. Importantly, all these effects of Set7/9 on cell metabolism were p53-independent. Bioinformatic analysis has shown a synergistic impact of Set7/9 together with either GLUT1, HIF1A, HK2, or LDHA on the survival of lung cancer patients. Based on these evidence, we hypothesize that Set7/9 can be an important regulator of energy metabolism in NSCLC.

Highlights

Lysine methylation plays an important role in global transcription regulation
To expand our observations on the role of Set7/9 in transcriptional regulation and to obtain the knowledge on global gene expression affected by Set7/9, we have carried out a microarray gene expression analysis of the same U2OS cells with Tet-inducible Set7/9 knockdown
Since our results suggested that ablation of Set7/9 caused an increase in CATAAAGTC TGCAACATGGAAGGT-3′ and reverse 5′-ATTTGATGG GTGAGGAATGGGTT-3′; Myc (c-Myc), GLUT1, and several glycolytic enzymes both at the messenger RNAs (mRNAs) and protein levels, we decided to examine whether Set7/9 affected the membrane mitochondrial potential (MMP), glycolysis, and respiration

Summary

Introduction

Lysine methylation plays an important role in global transcription regulation. Depending on the location of the target lysine in histone tails, this post-translational modification can either promote or repress transcription by affecting the architecture of chromatin. Lysine methylation, by competing with other lysine-specific modifications (e.g., acetylation, ubiquitinylation, and SUMOylation), can affect the protein stability and its functioning [1]. Set7/9 Regulates Metabolism of NSCLC Cells name SETD7) is a SET [Su(var)-3–9, Enhancer-of-Zeste, Trithorax] domain-containing protein that utilizes both histone and non-histone proteins as substrates. Set7/9 was shown to monomethylate lysine 4 of histone 3 (H3K4me1), which is a positive mark for transcriptional activation [2, 3]

Methods

Results

Conclusion