Protein kinase C epsilon promotes de novo lipogenesis and tumor growth in prostate cancer cells by regulating the phosphorylation and nuclear translocation of pyruvate kinase isoform M2

Glycolysis related lncRNA SNHG3 / miR-139-5p / PKM2 axis promotes castration-resistant prostate cancer (CRPC) development and enzalutamide resistance

Although androgen deprivation therapy (ADT) by the anti-androgen drug enzalutamide (Enz) may improve the survival level of patients with castration-resistant prostate cancer (CRPC), most patients may eventually fail due to the acquired resistance. The reprogramming of glucose metabolism is one type of the paramount hallmarks of cancers. PKM2 (Pyruvate kinase isozyme typeM2) is a speed-limiting enzyme in the glycolytic mechanism, and has high expression in a variety of cancers. Emerging evidence has unveiled that microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have impact on tumor development and therapeutic efficacy by regulating PKM2 expression. Herein, we found that lncRNA SNHG3, a highly expressed lncRNA in CRPC via bioinformatics analysis, promoted the invasive ability and the Enz resistance of the PCa cells. KEGG pathway enrichment analysis indicated that glucose metabolic process was tightly correlated with lncRNA SNHG3 level, suggesting lncRNA SNHG3 may affect glucose metabolism. Indeed, glucose uptake and lactate content determinations confirmed that lncRNA SNHG3 promoted the process of glycolysis. Mechanistic dissection demonstrated that lncRNA SNHG3 facilitated the advance of CRPC by adjusting the expression of PKM2. Further explorations unraveled the role of lncRNA SNHG3 as a 'sponge' of miR-139-5p and released its binding with PKM2 mRNA, leading to PKM2 up-regulation. Together, Our studies suggest that lncRNA SNHG3 / miR-139-5p / PKM2 pathway promotes the development of CRPC via regulating glycolysis process and provides valuable insight into a novel therapeutic approach for the disordered disease.

Inhibition of phosphoglycerate dehydrogenase induces ferroptosis and overcomes enzalutamide resistance in castration-resistant prostate cancer cells

Phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in the first step of the serine synthesis pathway (SSP), is overexpressed in multiple types of cancers. The androgen receptor inhibitor enzalutamide (Enza) is the primary therapeutic drug for patients with castration-resistant prostate cancer (CRPC). However, most patients eventually develop resistance to Enza. The association of SSP with Enza resistance remains unclear. In this study, we found that high expression of PHGDH was associated with Enza resistance in CRPC cells. Moreover, increased expression of PHGDH led to ferroptosis resistance by maintaining redox homeostasis in Enza-resistant CRPC cells. Knockdown of PHGDH caused significant GSH reduction, induced lipid peroxides (LipROS) increase and significant cell death, resulting in inhibiting growth of Enza-resistant CRPC cells and sensitizing Enza-resistant CRPC cells to enzalutamide treatment both in vitro and in vivo. We also found that overexpression of PHGDH promoted cell growth and Enza resistance in CRPC cells. Furthermore, pharmacological inhibition of PHGDH by NCT-503 effectively inhibited cell growth, induced ferroptosis, and overcame enzalutamide resistance in Enza-resistant CRPC cells both in vitro and in vivo. Mechanically, NCT-503 triggered ferroptosis by decreasing GSH/GSSG levels and increasing LipROS production as well as suppressing SLC7A11 expression through activation of the p53 signaling pathway. Moreover, stimulating ferroptosis by ferroptosis inducers (FINs) or NCT-503 synergistically sensitized Enza-resistant CRPC cells to enzalutamide. The synergistic effects of NCT-503 and enzalutamide were verified in a xenograft nude mouse model. NCT-503 in combination with enzalutamide effectively restricted the growth of Enza-resistant CRPC xenografts in vivo. Overall, our study highlights the essential roles of increased PHGDH in mediating enzalutamide resistance in CRPC. Therefore, the combination of ferroptosis inducer and targeted inhibition of PHGDH could be a potential therapeutic strategy for overcoming enzalutamide resistance in CRPC.

Roles of protein post-translational modifications in glucose and lipid metabolism: mechanisms and perspectives

The metabolism of glucose and lipids is essential for energy production in the body, and dysregulation of the metabolic pathways of these molecules is implicated in various acute and chronic diseases, such as type 2 diabetes, Alzheimer's disease, atherosclerosis (AS), obesity, tumor, and sepsis. Post-translational modifications (PTMs) of proteins, which involve the addition or removal of covalent functional groups, play a crucial role in regulating protein structure, localization function, and activity. Common PTMs include phosphorylation, acetylation, ubiquitination, methylation, and glycosylation. Emerging evidence indicates that PTMs are significant in modulating glucose and lipid metabolism by modifying key enzymes or proteins. In this review, we summarize the current understanding of the role and regulatory mechanisms of PTMs in glucose and lipid metabolism, with a focus on their involvement in disease progression associated with aberrant metabolism. Furthermore, we discuss the future prospects of PTMs, highlighting their potential for gaining deeper insights into glucose and lipid metabolism and related diseases.