Lipid metabolism and tumor immunotherapy

Lipid metabolism associated PLPP4 gene drives oncogenic and adipogenic potential in breast cancer cells

Lipid metabolic reprogramming plays a pivotal role in cancer cell evolution and causing subsequent cancer growth, metastasis and therapy resistance. Cancer associated adipocyte and/or cancer derived adipocyte-like cells often supply fuels and various factors to fulfill the cells bioenergetics to enhance oncogenic potential. This study intends to find out a set of dysregulated genes involved in lipid metabolism in breast cancer studies and uncovers the role of unexplored dysregulated gene in cancer potential. Cancer database analysis determines seven seed signature genes (PLPP2, PLPP4, CDS1, ASAH2, LCLAT1, LPCAT1 and LASS6/CERS6) concluded from relative expression and survival analysis. Furthermore, experimental analysis unveils the gene PLPP4 (Phospholipid Phosphatase 4) as oncogene confirmed by knockdown and overexpression studies in MDA-MB 231 and MCF-7 breast cancer cells. PLPP4 enzyme is involved in regulation of triacyl glycerol metabolism. Lipid accumulation along with other studies documented enhanced lipid droplets, TAG formation and glycerol release with concomitant increased expressions of various adipogenic markers (e.g., PPARγ, perilipin 1 and leptin) in breast cancer cells transfected with PLPP4 gene expressing plasmid whereas downregulation of PLPP4 gene diminished lipid accumulation and adipocyte marker gene expressions. Our findings also revealed that BMP2 induced adipogenic potential in breast cancer cells was mitigated in response to downregulation of PLPP4 gene expression. All these findings together, for first time, demonstrated that BMP2 drives PLPP4 to enhance both oncogenic and adipogenic potential in breast cancer cells. This article uncovers the perturbed lipid metabolism associated PLPP4 acts as oncogene presumably by modulating adipogenic activity in cancer cells.

Fatty acid metabolism: A new target for nasopharyngeal carcinoma therapy

Lipid metabolic reprogramming is considered one of the most prominent metabolic abnormalities in cancer, and fatty acid metabolism is a key aspect of lipid metabolism. Recent studies have shown that fatty acid metabolism and its related lipid metabolic pathways play important roles in the malignant progression of nasopharyngeal carcinoma (NPC). NPC cells adapt to harsh environments by enhancing biological processes such as fatty acid metabolism, uptake, production, and oxidation, thereby accelerating their growth. In addition, the reprogramming of fatty acid metabolism plays a central role in the tumor microenvironment (TME) of NPC, and the phenotypic transformation of immune cells is closely related to fatty acid metabolism. Moreover, the reprogramming of fatty acid metabolism in NPC contributes to immune escape, which significantly affects disease treatment, progression, recurrence, and metastasis. This review explores recent advances in fatty acid metabolism in NPC and focuses on the interconnections among metabolic reprogramming, tumor immunity, and corresponding therapies. In conclusion, fatty acid metabolism represents a potential target for NPC treatment, and further exploration is needed to develop strategies that target the interaction between fatty acid metabolic reprogramming and immunotherapy.

Exploring causal relationship between the lipids, immune cells, and leiomyosarcoma: A Mendelian randomization and mediation analysis

This study aimed to delineate the causal nexus between lipids and leiomyosarcoma (LMS), with a particular emphasis on delineating the mediating role of immune cells. Employing a 2-sample Mendelian randomization (MR) framework, we scrutinized the potential association of 179 lipid species with LMS across 179 cases and 314,193 controls. The analysis was underpinned by summary-level data derived from genome-wide association studies. The inverse variance weighting method constituted our primary analytical strategy, augmented by supplementary techniques including MR-Egger, simple mode, weighted median, and weighted mode. To ensure the integrity of our MR inferences, we conducted rigorous horizontal multiplicity, heterogeneity, and Bayesian assessments. Furthermore, a nuanced 2-step Mendelian analysis was undertaken to quantify the extent of immune cell-mediated effects of lipids on LMS. Our comprehensive MR evaluation of 179 lipids species unveiled a significant association between genetically inferred triglyceride levels and an elevated risk of LMS (odds ratio = 2.11, 95% confidence interval = 1.38-3.23, P < .001), while inversely showing no effect of LMS on triglyceride levels (odds ratio= 0.99, 95% confidence interval = 0.94-1.04, P = .83). Additionally, the examination of 731 immune cell phenotypes highlighted CD8+ natural killer T cells as contributing a 6% mediation in the causal pathway from triglycerides to LMS.

Integrated bioinformatics reveals genetic links between visceral obesity and uterine tumors

Visceral obesity (VO), characterized by excess fat around internal organs, is a recognized risk factor for gynecological tumors, including benign uterine leiomyoma (ULM) and malignant uterine leiomyosarcoma (ULS). Despite this association, the shared molecular mechanisms remain underexplored. This study utilizes an integrated bioinformatics approach to elucidate common molecular pathways and identify potential therapeutic targets linking VO, ULM, and ULS. We analyzed gene expression datasets from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs) in each condition. We found 101, 145, and 18 DEGs in VO, ULM, and ULS, respectively, with 37 genes overlapping across all three conditions. Functional enrichment analysis revealed that these overlapping DEGs were significantly enriched in pathways related to cell proliferation, immune response, and transcriptional regulation, suggesting shared biological processes. Protein-protein interaction network analysis identified 14 hub genes, of which TOP2A, APOE, and TYMS showed significant differential expression across all three conditions. Drug-gene interaction analysis identified 26 FDA-approved drugs targeting these hub genes, highlighting potential therapeutic opportunities. In conclusion, this study uncovers shared molecular pathways and actionable drug targets across VO, ULM, and ULS. These findings deepen our understanding of disease etiology and offer promising avenues for drug repurposing. Experimental validation is needed to translate these insights into clinical applications and innovative treatments.

Apolipoprotein E is a prognostic factor for pancreatic cancer and associates with immune infiltration

BACKGROUND

The expression level of apolipoprotein E (APOE) in pancreatic ductal adenocarcinoma (PDAC) and its effect on the prognosis of PDAC patients are not clear. The effect of APOE on the immune status of patients with PDAC has not been elucidated.

METHODS

We obtained pancreatic cancer data from the TCGA and GETx databases. Patients with PDAC who underwent pancreatic surgery at the Second Affiliated Hospital of Jiaxing University between 2012 and 2021 were included. Clinical pathological data were recorded, plasma APOE levels were measured, and tissue samples were collected. A tissue microarray was generated using the collected tissue samples. APOE and CD4 staining was performed to determine immunoreactive scores (IRSs). The expression of APOE in the plasma and tumour tissues of pancreatic cancer patients was analysed and compared. The correlations between plasma APOE levels, tissue APOE levels and clinicopathological characteristics were analysed. Survival prognosis was analysed using Kaplan-Meier survival analysis and Cox multivariate regression analysis. The correlations between APOE expression levels and immune biomarkers and immune cells were further analysed. Single-cell analysis of APOE distribution in various cells was performed on the TISCH website.

RESULTS

APOE was highly expressed in the tumour tissue of pancreatic cancer patients, and high plasma APOE levels were associated with poor prognosis. Females, patients with high-grade disease and patients with pancreatic head carcinoma had high plasma APOE levels. High APOE expression in tumour tissues was associated with good prognosis. Mononuclear macrophages in the pancreatic cancer microenvironment primarily expressed APOE. APOE levels positively correlated with immune biomarkers, such as CD8A, PDCD1, GZMA, CXCL10, and CXCL9, in the tumour microenvironment. APOE promoted CD4 + T cell or dendritic cell infiltration in the tumour microenvironment.

CONCLUSIONS

APOE may affect the occurrence and development of pancreatic cancer by regulating the infiltration of immune cells in the tumour microenvironment.

TMEM147: A Promising Cancer Biomarker Associated with Immune Cell Infiltration and Prognosis in LIHC-Insights from a Comprehensive Pan-Cancer Genomic Analysis

Previous studies have demonstrated the regulatory roles of Transmembrane protein 147 (TMEM147) in various diseases, including cancer. However, systematic pan-cancer analyses investigating the role of TMEM147 in diagnosis, prognosis, and immunological prediction are lacking. An analysis of data from The Cancer Genome Atlas (TCGA) revealed differential TMEM147 expression across various types of cancer as well as within immune and molecular cancer subtypes. Moreover, high TMEM147 expression was associated with poor disease-specific survival (DSS), overall survival (OS), and progression-free interval (PFI) across cancers, suggesting its potential as a prognostic biomarker. Our study further revealed a significant correlation between TMEM147 expression and T helper cell and Tcm cell infiltration in most cancer types. In the case of liver hepatocellular carcinoma (LIHC), the effect of TMEM147 on prognosis varied among different clinical subtypes. Additionally, functional enrichment analysis revealed an association between TMEM147 and metabolic pathways. Finally, experiments on the MIHA cell line and four LIHC cell lines confirmed the role of TMEM147 in promoting liver cancer cell proliferation, further confirming the clinical value of TMEM147 in liver cancer diagnosis. Our findings suggest that TMEM147 may serve as a diagnostic and prognostic biomarker across cancers while also playing a significant role in LIHC.

VLDL and LDL Subfractions Enhance the Risk Stratification of Individuals Who Underwent Epstein-Barr Virus-Based Screening for Nasopharyngeal Carcinoma: A Multicenter Cohort Study

Serological tests for Epstein-Barr virus (EBV) antibodies have been widely conducted for the screening of nasopharyngeal carcinoma (NPC) in endemic areas. Further risk stratification of NPC can be achieved through plasma lipoprotein and metabolic profiles. A total of 297 NPC patients and 149 EBV-positive participants are enrolled from the NCT03919552 and NCT05682703 cohorts for plasma nuclear magnetic resonance (NMR) metabolomic analysis. Small, dense very low density lipoprotein particles (VLDL-5) and large, buoyant low density lipoprotein particles (LDL-1) are found to be closely associated with nasopharyngeal carcinogenesis. Herein, an NMR-based risk score (NRS), which combines lipoprotein subfractions and metabolic biomarkers relevant to NPC, is developed and well validated within a multicenter cohort. Combining the median cutoff value of the NRS (N50) with that of the serological test for EBV antibodies, the risk stratification model achieves a satisfactory performance in which the area under the curve (AUC) is 0.841 (95% confidence interval: 0.811-0.871), and the positive predictive value (PPV) reaches 70.08% in the combined cohort. These findings not only suggest that VLDL-5 and LDL-1 particles can serve as novel risk factors for NPC but also indicate that the NRS has significant potential in personalized risk prediction for NPC.

Alterations in Plasma Lipid Profiles Associated with Melanoma and Therapy Resistance

Dysfunctions of lipid metabolism are associated with tumor progression and treatment resistance of cutaneous melanoma. BRAF/MEK inhibitor resistance is linked to alterations of melanoma lipid pathways. We evaluated whether a specific lipid pattern characterizes plasma from melanoma patients and their response to therapy. Plasma samples from patients and controls were analyzed for FASN and DHCR24 levels and lipidomic profiles. FASN and DHCR24 expression resulted in association with disease condition and related to plasma cholesterol and triglycerides in patients at different disease stages (n = 144) as compared to controls (n = 115). Untargeted lipidomics in plasma (n = 40) from advanced disease patients and controls revealed altered levels of different lipids, including fatty acid derivatives and sphingolipids. Targeted lipidomics identified higher levels of dihydroceramides, ceramides, sphingomyelins, ganglioside GM3, sphingosine, sphingosine-1-phosphate, and dihydrosphingosine, saturated and unsaturated fatty acids. When melanoma patients were stratified based on a long/short-term clinical response to kinase inhibitors, differences in plasma levels were shown for saturated fatty acids (FA 16:0, FA18:0) and oleic acid (FA18:1). Our results associated altered levels of selected lipid species in plasma of melanoma patients with a more favorable prognosis. Although obtained in a small cohort, these results pave the way to lipidomic profiling for melanoma patient stratification.

ACSM5 inhibits ligamentum flavum hypertrophy by regulating lipid accumulation mediated by FABP4/PPAR signaling pathway

BACKGROUND

Ligamentum flavum (LF) hypertrophy is the main cause of lumbar spinal canal stenosis (LSCS). Previous studies have shown that LF hypertrophy tissue exhibits abnormal lipid accumulation, but the regulatory mechanism remains unclear. The objective of this study was to explore the function and potential mechanism of ACSM5 in LF lipid accumulation.

METHODS

To assess the ACSM5 expression levels, lipid accumulation and triglyceride (TG) level in LF hypertrophy and normal tissue, we utilized RT-qPCR, western blot, oil red O staining, and TG assay kit. The pearson correlation coefficient assay was used to analyze the correlation between ACSM5 levels and lipid accumulation or TG levels in LF hypertrophy tissue. The role of ACSM5 in free fatty acids (FFA)-induced lipid accumulation in LF cells was assessed in vitro, and the role of ACSM5 in LF hypertrophy in mice was verified in vivo. To investigate the underlying mechanisms of ACSM5 regulating lipid accumulation in LF, we conducted the mRNA sequencing, bioinformatics analysis, and rescue experiments.

RESULTS

In this study, we found that ACSM5, which was significantly down-regulated in LF tissues, correlated with lipid accumulation. In vitro cell experiments demonstrated that overexpression of ACSM5 significantly inhibited FFA-induced lipid accumulation and fibrosis in LF cells. In vivo animal experiments further confirmed that overexpression of ACSM5 inhibited LF thickening, lipid accumulation, and fibrosis. Mechanistically, ACSM5 inhibited lipid accumulation of LF cells by inhibiting FABP4-mediated PPARγ signaling pathway, thereby improving hypertrophy and fibrosis of LF.

CONCLUSIONS

our findings elucidated the important role of ACSM5 in the regulation of LF lipid accumulation and provide insight into potential therapeutic interventions for the treatment of LF hypertrophy. This study further suggested that therapeutic strategies targeting lipid deposition may be an effective potential approach to treat LF hypertrophy-induced LSCS.

Decoding the genetic links between serum lipidomic profile, amino acid biomarkers, and programmed cell death protein-1/programmed cell death-ligand-1

BACKGROUND

Disruptions in lipid metabolism and amino acids have been increasingly linked to resistance to immunotherapy. However, the underlying mechanisms by which dysregulated serum lipid metabolism and amino acids affect the efficacy of immunotherapies through PD-1/PD-L1 expression and function remain poorly understood.

METHODS

To elucidate the potential associations between lipid metabolism, amino acids, and PD-1/PD-L1, we employed the powerful Mendelian randomization (MR) method, leveraging large-scale genome-wide association studies.

RESULTS

In the present MR study, we identified a noteworthy negative association between alanine and PD-1 expression, implicating a regulatory role for alanine metabolism in modulating the immune response to cancer treatment. Additionally, we elucidated fourteen specific lipid metabolism biomarkers that were significantly linked to PD-L1 expression, including cholesterol and triglycerides. Glutamine and phenylalanine were also found to showcase an intriguing causal association with the expression of PD-L1. Eventually, we confirmed the potential roles of key genes involved in lipid and amino acids metabolism in influencing the response to immunotherapy.

CONCLUSIONS

These findings provided new insights into the role of lipid metabolism as well as amino acids in regulating PD-1/PD-L1, suggesting that strategies targeting lipid and amino acid metabolisms may have therapeutic potential for improving the efficacy of immunotherapy.