Peroxisomal β-oxidation enzyme, DECR2, regulates lipid metabolism and promotes treatment resistance in advanced prostate cancer

The unusual metabolism of germinal center B cells

In the germinal center (GC), B cells undergo rounds of somatic hypermutation (SHM), proliferation, and positive selection to develop into high-affinity, long-lived plasma cells and memory B cells. It is well established that, upon activation, B cells significantly alter their metabolism, but until recently little was understood about their metabolism within the GC. In this review we discuss novel in vivo models in which GC B cell (GCBC) metabolism is disrupted; these have greatly increased our understanding of B cell metabolic phenotype. GCBCs are unusual in that, unlike almost all other rapidly proliferating immune cells, they use little glycolysis but prefer fatty acid oxidation (FAO) to fuel ATP synthesis, whilst preferentially utilizing glucose and amino acids as carbon and nitrogen sources for biosynthetic pathways.

Lipid-metabolism-focused CRISPR screens identify enzymes of the mevalonate pathway as essential for prostate cancer growth

Dysregulated lipid metabolism plays an important role in prostate cancer, although the understanding of the essential regulatory processes in tumorigenesis is incomplete. We employ a CRISPR-Cas9 screen using a custom human lipid metabolism knockout library to identify essential genes for prostate cancer survival. Screening in three prostate cancer cell lines reveals 63 shared dependencies, with enrichment in terpenoid backbone synthesis and N-glycan biosynthesis. Independent knockout of key genes of the mevalonate pathway reduces cell proliferation. Further investigation focuses on NUS1, a subunit of cis-prenyltransferase required for dolichol synthesis. NUS1 knockout decreases tumor growth in vivo and viability in patient-derived xenograft (PDX)-derived organoids. Mechanistic studies reveal that loss of NUS1 promotes oxidative stress, lipid peroxidation and ferroptosis sensitivity, endoplasmic reticulum (ER) stress, and G1 cell-cycle arrest, and it dampens androgen receptor (AR) signaling, collectively leading to growth arrest. This study highlights the critical role of the mevalonate-dolichol-N-glycan biosynthesis pathway, particularly NUS1, in prostate cancer survival and growth.

Metabolic phenotypes and fatty acid profiles associated with histopathology of primary aldosteronism

Primary aldosteronism (PA) caused by aldosterone hypersecretion is treated by adrenalectomy or medications. Histopathologic examination of resected adrenals reveals diverse histopathologic features. This study aimed to investigate the potential association of peripheral and adrenal tissue metabolic profiles with the histopathologic features of PA. The retrospective study included 105 surgically treated and 43 medically treated patients with PA. Adrenal specimens were categorized according to the HISTALDO (HISTopathology of primary ALDOsteronism) consensus. Peripheral and adrenal tissue metabolic profiles were assessed, including adiposity, adipokines and fatty acid abundances. The distinct fatty acid, arachidonic acid, was further functionally characterized. Surgically treated patients with classical histopathologic findings (n = 71) displayed lower body mass indexes, a lower prevalence of obesity, smaller waist circumference and visceral adipose tissue areas, and lower leptin concentrations compared with operated patients with the nonclassical histopathology (n = 34). No such differences were identified between the nonclassical histopathology group and medically treated group. Distinct concentrations of 18 out of 35 peripheral venous fatty acids, including arachidonic acid, were identified among the 3 groups. Further, accumulation of arachidonic acid was demonstrated in 4 aldosterone-producing adenomas compared with paired adjacent cortex possibly linked with suppressed peroxisomal beta-oxidation. Stimulation of human adrenocortical cells with arachidonic acid or peroxisomal beta-oxidation inhibitor caused 3.8-fold (P = 0.0050) and 1.7-fold (P = 0.0328) amplification of CYP11B2 expression, respectively, which were ablated by BAPTA-AM or KN93, and induced oxidative stress and apoptosis. Our findings show metabolic heterogeneity related to histopathology and support a role for arachidonic acid in PA pathophysiology.

Utility of a Large Series of B-Cell Precursor Acute Lymphoblastic Leukemia Cell Lines as a Model System

BACKGROUND

In B-cell precursor acute lymphoblastic leukemia (BCP-ALL), chromosomal translocations are strongly associated with prognoses. RNA sequencing (RNA-seq) is a powerful technology that reveals a close correlation between types of translocation and patterns of gene expression in clinical samples of BCP-ALL. Cancer cell lines are powerful research tools, and thus, we built a larger series of BCP-ALL cell lines and performed RNA-seq analysis to confirm their utility as a model system.

METHODS

We performed RNA-seq in a total of 94 BCP-ALL cell lines, including 80 cell lines with 8 representative types of translocations.

RESULTS

In the UMAP visualization, a close association was confirmed between the types of fusion genes and patterns of gene expression. In the cluster analysis of the gene expression profile, each type of fusion gene showed a clear association with the expression profile in the top 51 variable genes. Of clinical importance, the majority of the top variable genes in the BCP-ALL cell lines also showed a significant association with the types of fusion genes in the clinical samples. When an association of 125 cell cycle-related genes with the percentage of S and G2/M phases in 67 cell lines was evaluated, a significant positive correlation with cell cycle progression was confirmed in 10 cell cycle-related genes (HDAC2, CDC23, YWHAG, MAD2L1, CCNH, ANAPC7, CDC6, ANAPC5, ORC3, andRBX1). Moreover, significant upregulation and downregulation of 40 and 10 genes, respectively, were observed in the cell lines established at relapse compared with those established at diagnosis. Four (SP6, CCNE1, HIST1H2BH, and DECR2) and two (EVI2B and SYN1) of these genes were also significantly higher and lower, respectively, in the clinical samples at relapse than in those at diagnosis.

CONCLUSION

Large series of BCP-ALL cell lines is a powerful research tool for studying the mechanisms of leukemogenesis and the disease progression of BCP-ALL.

Combined Blockade of Lipid Uptake and Synthesis by CD36 Inhibitor and SCD1 siRNA Is Beneficial for the Treatment of Refractory Prostate Cancer

Drug resistance is an important factor for prostate cancer (PCa) to progress into refractory PCa, and abnormal lipid metabolism usually occurs in refractory PCa, which presents great challenges for PCa therapy. Here, a cluster of differentiation 36 (CD36) inhibitor sulfosuccinimidyl oleate sodium (CD36i) and stearoyl-CoA desaturase 1 (SCD1) siRNA (siSCD1) are selected to inhibit lipid uptake and synthesis in PCa, respectively. To this end, a multiresponsive drug delivery nanosystem, HA@CD36i-TR@siSCD1 is designed. The hyaluronic acid (HA) gel "shell" of HA-TR nanosystem can release drugs in response to the acidic tumor microenvironment and hyaluronidase, and the tumor targeting (TR) cationic micellar "core" can release drugs in response to glutathione. This multiresponsive drug release is beneficial for the exogenous inhibition of lipid uptake by CD36i and the endogenous inhibition of lipid synthesis by siSCD1. The established HA-TR nanosystem has good tumor targeting ability and tumor penetration ability, and that HA@CD36i-TR@siSCD1 has good synergistic effects, which can significantly restrain the growth, invasion, and metastasis of PCa. Moreover, under high-fat conditions, the tumors are more sensitive to HA@CD36i-TR@siSCD1 treatment, almost no accumulation of lipid droplets is observed in HA@CD36i-TR@siSCD1-treated tumors, with enhanced antitumor immunity. Hence, this study provides a new treatment option for refractory PCa patients, especially those with a high-fat diet.

Acetylation of proximal cysteine-lysine pairs by alcohol metabolism

Alcohol consumption induces hepatocyte damage through complex processes involving oxidative stress and disrupted metabolism. These factors alter proteomic and epigenetic marks, including alcohol-induced protein acetylation, which is a key post-translational modification (PTM) that regulates hepatic metabolism and is associated with the pathogenesis of alcohol-associated liver disease (ALD). Recent evidence suggests lysine acetylation occurs when a proximal cysteine residue is within ∼15 Å of a lysine residue, referred to as a cysteine-lysine (Cys-Lys) pair. Here, acetylation can occur through the transfer of an acetyl moiety via an S → N transfer reaction. Alcohol-mediated redox stress is known to occur coincidentally with lysine acetylation, yet the biochemical mechanisms related to cysteine and lysine crosstalk within ALD remain unexplored. A murine model of ALD was employed to quantify hepatic cysteine redox changes and lysine acetylation, revealing that alcohol metabolism significantly reduced the cysteine thiol proteome and increased protein acetylation. Interrogating both cysteine redox and lysine acetylation datasets, 1280 protein structures generated by AlphaFold2 represented by a 3D spatial matrix were used to quantify the distances between 557,815 cysteine and lysine residues. Our analysis revealed that alcohol metabolism induces redox changes and acetylation selectively on proximal Cys-Lys pairs with an odds ratio of 1.88 (p < 0.0001). Key Cys-Lys redox signaling hubs were impacted in metabolic pathways associated with ALD, including lipid metabolism and the electron transport chain. Proximal Cys-Lys pairs exist as sets with four major motifs represented by the number of Cys and Lys residues that are pairing (Cys1:Lys1, Cysx:Lys1, Cys1:Lysx and Cysx:Lysx) each with a unique microenvironment. The motifs are composed of functionally relevant Cys-Ly altered within ALD, identifying potential therapeutic targets. Furthermore, these unique Cys-Lys redox signatures are translationally relevant as revealed by orthologous comparison with severe alcohol-associated hepatitis (SAH) explants, revealing numerous pathogenic thiol redox signals in these patients.

Peroxisome inter-organelle cooperation in Drosophila

Many cellular functions are compartmentalized within the optimized environments of organelles. However, processing or storage of metabolites from the same pathway can occur in multiple organelles. Thus, spatially separated organelles need to cooperate functionally. Coordination between organelles in different specialized cells is also needed, with shared metabolites passed via circulation. Peroxisomes are membrane-bounded organelles responsible for cellular redox and lipid metabolism in eukaryotic cells. Peroxisomes coordinate with other organelles including mitochondria, endoplasmic reticulum, lysosomes, and lipid droplets. This functional coordination requires, or is at least enhanced by, direct contact between peroxisomes and other organelles. Peroxisome dysfunction in humans leads to multiorgan effects including neurological, metabolic, developmental, and age-related diseases. Thus, increased understanding of peroxisome coordination with other organelles, especially cells in various organs is essential. Drosophila melanogaster (fruit fly) has emerged recently as an effective animal model for understanding peroxisomes. Here we review current knowledge of pathways regulating coordination between peroxisomes with other organelles in flies, speculating about analogous roles for conserved Drosophila genes encoding proteins with known organelle coordinating roles in other species.

Characterization of the Peroxisomal Proteome and Redox Balance in Human Prostate Cancer Cell Lines

Prostate cancer (PCa) is associated with disruptions in cellular redox balance. Given the intricate role of peroxisomes in redox metabolism, we conducted comprehensive proteomics analyses to compare peroxisomal and redox protein profiles between benign (RWPE-1) and malignant (22Rv1, LNCaP, and PC3) prostate cell lines. Our analyses revealed significant enrichment of the "peroxisome" pathway among proteins notably upregulated in androgen receptor (AR)-positive cell lines. In addition, catalase (CAT) activity was consistently higher in these malignant cell lines compared to RWPE-1, which contrasts with previous studies reporting lower CAT levels and increased H2O2 levels in PCa tissues compared to adjacent normal tissues. To mimic this clinical scenario, we used RNA interference to knock down CAT expression. Our results show that reduced CAT levels enhanced 22Rv1 and LNCaP cell proliferation. R1881-induced activation of AR, a key driver of PCa, increased expression of the H2O2-producing peroxisomal β-oxidation enzymes acyl-coenzyme A oxidase 1 and 3, reduced CAT expression and activity, and elevated peroxisomal H2O2 levels. Considering these changes and other antioxidant enzyme profile alterations, we propose that enhanced AR activity in PCa reduces CAT function, leading to increased peroxisomal H2O2 levels that trigger adaptive stress responses to promote cell survival, growth, and proliferation.

Darolutamide-mediated phospholipid remodeling induces ferroptosis through the SREBP1-FASN axis in prostate cancer

Darolutamide, an androgen receptor inhibitor, has been approved by the Food and Drug Administration (FDA) for the treatment of prostate cancer (PCa), especially for patients with androgen receptor mutations. Owing to the unique lipidomic profile of PCa and the effect of darolutamide, the relationship between darolutamide and ferroptosis remains unclear. The present study showed that darolutamide significantly induces ferroptosis in AR+ PCa cells. Mechanistically, darolutamide promotes ferroptosis by downregulating SREBP1, which then inhibits the transcription of FASN. FASN knockdown modulates phospholipid remodeling by disrupting the balance between polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs), which induces ferroptosis. Clinically, SREBP1 and FASN are significantly overexpressed in PCa tissues and are related to poor prognosis. Moreover, the synergistic antitumor effect of combination therapy with darolutamide and ferroptosis inducers (FINs) was confirmed in PCa organoids and a mouse xenografts model. Overall, these findings revealed a novel mechanism of darolutamide mediated ferroptosis in PCa, laying the foundation for the combination of darolutamide and FINs as a new therapeutic strategy for PCa patients.

ENO2 promotes anoikis resistance in anaplastic thyroid cancer by maintaining redox homeostasis

Background

Anoikis presents a significant barrier in the metastasis of cancer. As the most aggressive type of thyroid cancer, anaplastic thyroid cancer (ATC) exhibits a high risk of metastasis and is characterized by high mortality. Therefore, investigating the molecular mechanisms of anoikis resistance in ATC is important for devising therapeutic targets in clinical research.

Methods

Differentially Expressed Genes were screened in ATC cells under attached and detached culture conditions with RNA-seq. Investigate the impact of enolase 2 (ENO2) on apoptosis and spheroid formation by gain and loss of function. Changes of reactive oxygen species (ROS), glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH) were detected to assess redox balance. The transcriptional regulatory role of signal transducer and activator of transcription 1 (STAT1) on ENO2 was validated through Dual-Luciferase Reporter Gene Assay. Explore the impact of ENO2 expression on the formation of lung metastases in nude mice.

Results

We found that the glycolysis process was activated in detached ATC cells. Several genes in the glycolysis process, particularly ENO2, a member of the enolase superfamily was upregulated in ATC cells cultured in suspension. The upregulation of ENO2 enabled the maintenance of redox balance by supplying GSH and NADPH, thereby preventing cells from undergoing anoikis. In terms of mechanism, the expression of STAT1 was enhanced in anoikis resistance cells, which in turn positively regulated the expression of ENO2. In vivo, ENO2-suppressed ATC cells resulted in a significantly lower rate of lung colonization compared to control ATC cells.

Conclusions

Stable expression of ENO2 and the maintenance of redox balance played a pivotal role in facilitating anoikis resistance of ATC.