NEK2 Promotes Aerobic Glycolysis in Multiple Myeloma Through Regulating Splicing of Pyruvate Kinase

Abstract

BackgroundAerobic glycolysis, a hallmark of cancer, is characterized by increased metabolism of glucose and production of lactate in normaxia. Recently, pyruvate kinase M2 (PKM2) has been identified as a key player for regulating aerobic glycolysis and promoting tumor cell proliferation and survival.MethodsTandem affinity purification followed up by mass spectrometry (TAP-MS) and co-immunoprecipitation (Co-IP) were used to study the interaction between NIMA (never in mitosis gene A)-related kinase 2 (NEK2) and heterogeneous nuclear ribonucleoproteins (hnRNP) A1/2. RNA immunoprecipitation (RIP) was performed to identify NEK2 binding to PKM pre-mRNA sequence. Chromatin-immunoprecipitation (ChIP)-PCR was performed to analyze a transcriptional regulation of NEK2 by c-Myc. Western blot and real-time PCR were executed to analyze the regulation of PKM2 by NEK2.ResultsNEK2 regulates the alternative splicing of PKM immature RNA in multiple myeloma cells by interacting with hnRNPA1/2. RIP shows that NEK2 binds to the intronic sequence flanking exon 9 of PKM pre-mRNA. Knockdown of NEK2 decreases the ratio of PKM2/PKM1 and also other aerobic glycolysis genes including GLUT4, HK2, ENO1, LDHA, and MCT4. Myeloma patients with high expression of NEK2 and PKM2 have lower event-free survival and overall survival. Our data indicate that NEK2 is transcriptionally regulated by c-Myc in myeloma cells. Ectopic expression of NEK2 partially rescues growth inhibition and cell death induced by silenced c-Myc.ConclusionsOur studies demonstrate that NEK2 promotes aerobic glycolysis through regulating splicing of PKM and increasing the PKM2/PKM1 ratio in myeloma cells which contributes to its oncogenic activity.

Inhibition of autophagy enhances the antitumour activity of tigecycline in multiple myeloma

“…We mainly clarified the upstream mechanisms of autophagy induction and found that the activation of AMPK is implicated in tigecycline‐induced autophagy. In contrast to normal cells, MM cells relied heavily on glycolysis and mitochondrial respiration to meet the high demands of energy production and metabolism . Tigecycline as a mitochondrial protein translation inhibitor leads to energy deprivation, and AMPK is a crucial cellular energy sensor.…”

Plasma cells: You are what you eat

“…191,192 While it is difficult to culture myeloma cells from patients in routine cell culture media, a model for studying this disease exists in mice, which involves transplantation of the spontaneously arising 5TMM cells from aged C57BL/KaLwRij mice into syngeneic younger recipients 193,194 (discussed more recently in 195 ). In addition to cytokines such as IL-6 and BAFF that promote normal plasma cell sur- 207,208 This tendency toward aerobic glycolysis, or the Warburg effect, is a unique feature of highly proliferative cells and is likely to shunt the excess of pyruvate toward lactate formation, which in turn is excreted through the monocarboxylate transporters MCT1 and MCT4. 196,197 While extracellular survival factors and niches may be limiting for normal long-lived plasma cell survival and numbers, MM growth and maintenance becomes independent of such constraints.…”

Multiple Myeloma and Fatty Acid Metabolism

“…Fatty acids are not only metabolized in MM cells, but also play a host of other roles in MM. One study found that ω‐3 polyunsaturated fatty acids specifically (often thought of as a healthy fat), enhances dexamethasone sensitivity in MM cells . The mechanism of this was found to be an increase in miR‐34a in MM cells, which likely suppresses Bcl‐2 .…”

“…One study found that ω‐3 polyunsaturated fatty acids specifically (often thought of as a healthy fat), enhances dexamethasone sensitivity in MM cells . The mechanism of this was found to be an increase in miR‐34a in MM cells, which likely suppresses Bcl‐2 . Fatty acids are also essential in the construction of the plasma membranes of the cell membrane and its organelles.…”