Targeting cholesterol metabolism in Cancer: From molecular mechanisms to therapeutic implications

Reprogramming and targeting of cholesterol metabolism in tumor-associated macrophages

Cholesterol, as a major component of cell membranes, is closely related to the metabolic regulation of cells and organisms; tumor-associated macrophages play an important push role in tumor progression. We know that tumor-associated macrophages are polarized from macrophages, and the abnormalities of cholesterol metabolism that may be induced during their polarization are worth discussing. This manuscript focuses on metabolic abnormalities in tumor-associated macrophages, and first provides a basic summary of the regulatory mechanisms of abnormal macrophage polarization. Subsequently, it comprehensively describes the features of abnormal glucose, lipid and cholesterol metabolism in TAMs as well as the different regulatory pathways. Then, the paper also discusses the link between abnormal cholesterol metabolism in TAMs and tumors, chronic diseases and aging. Finally, the paper summarizes cancer therapeutic strategies targeting cholesterol metabolism that are already in clinical trials, as well as nanomaterials capable of targeting cholesterol metabolism that are in the research stage, in the hope of providing value for the design of targeting materials. Overall, elucidating metabolic abnormalities in tumor-associated macrophages, particularly cholesterol metabolism, could provide assistance in tumor therapy and the design of targeted drugs.

Recent Advances in the Development of Sigma Receptor (Radio)Ligands and Their Application in Tumors

Cancer ranks among the top triumvirate leading causes of human deaths worldwide. The pathological mechanisms are notably intricate, demonstrating proliferative and metastatic capabilities, which complicate therapeutic interventions. The sigma-1 receptor (σ1R) plays a crucial role in tumor survival and migration, while the sigma-2 receptor (σ2R) is intimately associated with tumor proliferation. This review encapsulated the investigation concerning σ1R and σ2R in neoplasms and rigorously summarized the ligands and radio-ligands development and their tumor applications, such as antitumor cell proliferation and PET/SPECT imaging in tumors. A comprehensive classification discussion was undertaken regarding the chemical structures and emphasized the possibility of dual/multitargeted ligands. Ultimately, we discussed the effects of chiral structures and the pharmacological characteristics of ligands on affinity and pharmacokinetic features in vivo, particularly concerning radiopharmaceuticals. This review functions as a beneficial resource, fostering ligand deployment and stimulating the generation of innovative ideas for developing innovative radiopharmaceuticals.

Dual targeting PPARα and NPC1L1 metabolic vulnerabilities blocks tumorigenesis

Dysregulated lipid metabolism is linked to tumor progression. In this study, we identified Niemann-Pick C1-like 1 (NPC1L1) as a downstream effector of PKM2. In breast cancer cells, PKM2 knockout (KO) enhanced NPC1L1 expression while downregulating peroxisome proliferator-activated receptor α (PPARα) signaling pathway. PPARα and nuclear factor-E2 p45-related factor 1/2(Nrf1/2) are transcription factors regulating NPC1L1. In vitro PKM2 KO enhanced recruitment of Nrf1/2 to the NPC1L1 promoter region. Fenofibrate, a PPARα activator, promoted NPC1L1 expression; ezetimibe, an NPC1L1 inhibitor and effective Nrf2 activator, also elevated NPC1L1 expression. Combined administration of fenofibrate and ezetimibe significantly induced cytoplasmic vacuolation, and cell apoptosis. Mechanistically, this combined administration activated inositol required enzyme 1α(IRE1α) and produced the spliced form of X-box binding protein (XBP1s), which in turn enhanced lysine demethylase 6B (KDM6B) transcription. XBP1s interacts with KDM6B to activate genes involved in the unfolded protein response by demethylating di- and tri-methylated lysine 27 of histone H3 (H3K27), consequently increasing H3K27 acetylation levels in breast cancer cell lines. Fenofibrate and ezetimibe synergistically inhibited tumor growth in vivo. Our findings reveal that dual targeting of PPARα and NPC1L1 may represent a novel therapeutic regimen for breast cancer therapy.

From natural herbal wisdom to nano innovation: Revolutionizing tumor treatment through intervening in metabolic reprogramming

In recent years, with the deepening understanding of the biological mechanisms underlying tumorigenesis, metabolic reprogramming has emerged as a pivotal process in cancer initiation, progression, and treatment resistance, gradually paving the way for new avenues in precision oncology. Natural herbal ingredients, characterized by their multi-target engagement, low toxicity, and wide-ranging biological activities, exhibit unique advantages in anti-cancer therapy. Nonetheless, the clinical application of these components has been constrained by issues such as poor solubility, low bioavailability, and inadequate stability when administered through traditional delivery methods. The advent of multifunctional nanoformulations has offered solutions to these challenges, substantially advancing the utilization of natural herbal components in precision therapy targeting tumor metabolic reprogramming. This article provides a comprehensive review of the multidimensional features of cancer metabolic reprogramming and its intricate regulatory network, highlighting the latest advancements in metabolic regulation, targeted delivery, and precision therapy achieved through natural herbs and their multifunctional nanomedicines. It also offers insights into future directions in this field. We are justified in believing that continued breakthroughs in this area will usher in safer and more effective treatment options for cancer patients, heralding a new chapter in cancer therapy.

Targeting piRNA-137463 Inhibits Tumor Progression and Boosts Sensitivity to Immune Checkpoint Blockade via De Novo Cholesterol Biosynthesis in Lung Adenocarcinoma

The important role of PIWI-interacting RNAs (piRNAs) in tumors has garnered increasing attention. However, research on their role in lung adenocarcinoma (LUAD) remains limited. Elevated levels of piRNA-137463 have been linked to poor prognosis in LUAD patients. Inhibition of piRNA-137463 curbed the proliferation, migration, and invasion of LUAD cells, enhanced T cell cytotoxicity through increased IFN-γ secretion, disrupted cholesterol metabolism, and reduced intracellular cholesterol, lipid raft content, and PD-L1 expression in LUAD cells. Bioinformatic prediction identified a potential interaction between piRNA-137463 and lncRNA LOC100128494. Inhibiting piRNA-137463 increased the stability and expression of LOC100128494, which further modulated insulin-induced gene 1 protein (INSIG1) levels via a competitive endogenous RNA network involving LOC100128494 and miR-24-3p. Notably, the effect of piRNA-137463 in LUAD cells is dependent on the expression of LOC100128494 and INSIG1. Inhibiting the expression of piRNA-137463 with AntagopiRNA-137463 suppressed tumor growth and metastasis via LOC100128494 in nude mice and enhanced the response of LUAD to anti-PD-1 therapy in immune-competent mice. In summary, this study elucidates the role of piRNA-137463 in the reprogramming of cholesterol metabolism, which drives the progression of LUAD, thereby identifying a new target for the comprehensive clinical management of LUAD.

Development of a Prognostic Nomogram Incorporating the Naples Prognostic Score for Postoperative Oral Squamous Cell Carcinoma Patients

Background

The Naples prognostic score (NPS) and its relation to the prognosis of oral squamous cell carcinoma (OSCC) have been inconclusive. This study aimed to investigate the correlation between NPS and the prognosis of postoperative OSCC patients. Additionally, the study sought to develop a new nomogram for predicting disease-free survival (DFS) and overall survival (OS).

Methods

The study included 576 OSCC patients who underwent surgical treatment at two hospitals between August 2008 and June 2018. Univariate and multivariate Cox regression analyses were conducted to identify independent prognostic factors. Subsequently, two nomograms were developed to predict DFS and OS based on these factors and underwent rigorous validation.

Results

The median DFS and OS were 31.5 months and 36.5 months, respectively. Significant differences in DFS and OS were observed among patients with different NPS scores. Adjuvant radiotherapy, age-adjusted Charlson comorbidity index (ACCI), extranodal extension (ENE), NPS, American Joint Committee on Cancer (AJCC) stage, surgical safety margin, eastern cooperative oncology group performance status (ECOG PS), and systemic inflammation score (SIS) were identified as independent predictors of DFS and OS. In the training cohort, the nomogram's concordance index (C-index) for predicting DFS and OS was 0.701 and 0.693, respectively. In the validation group, the corresponding values were 0.642 and 0.635, respectively. Calibration plots confirmed a high level of agreement between the model's predictions and actual outcomes. Decision curve analysis (DCA) demonstrated the nomogram's good clinical utility. Additionally, patients in the low-risk group did not benefit from adjuvant radiotherapy, while those in the medium-risk and high-risk group could benefit from adjuvant radiotherapy.

Conclusion

NPS significantly influences the prognosis of OSCC patients following surgery. The nomogram developed in this study holds significant clinical application potential. The low-risk subgroup of patients was not required to undergo postoperative radiotherapy.

The impact of PTEN status on glioblastoma multiforme: A glial cell type-specific study identifies unique prognostic markers

Glioblastoma multiforme (GBM) is the most invasive form of brain tumor, accounting for 5 % of the cases per 100,000 people in various countries. The phosphatase and tensin homolog deleted from chromosome 10 (PTEN) is a well-known tumor suppressor, and its alteration leads to a deleterious effect on GBM progression. The molecular mechanism of tumorigenesis in glial cell types, driven by PTEN status, is yet to be elucidated. In this study, we analyzed publicly available single-cell transcriptome profiles of PTEN wild-type (WT) and NULL GBM patients. We compared them with normal brain data to uncover many unique gene sets influenced by PTEN status. The co-expression network analysis of differentially expressed genes (DEGs) between normal brain and PTEN (WT and NULL) identified highly interconnected genes. The weighted gene co-expression network analysis (WGCNA), based on the DESeq2 algorithm, identified glial cell-type-specific modules in PTEN status-dependent bulk RNA expression profiles. We overlapped network module gene sets from single-cell and bulk transcriptome profiles, and shared genes were considered for further analysis. The hallmark pathway enrichment analysis of the genes unique to PTEN-WT and NULL revealed various tumor growth-related pathways across the glial cell types. Further characterization of PTEN-WT and PTEN-NULL networks belonging to the single-cell and bulk RNA datasets revealed that PTEN status influences the network modules in astrocytes, microglia, and oligodendrocyte precursor cells. An integrated influence value algorithm identified hub genes for each glial cell type. The prognostic analysis identified clinically relevant hub genes specific to the cell type in PTEN-WT: GLIPR2 (astrocytes), CFH, IL32, MXRA5 (microglia), and PTEN-NULL: ID1 (astrocytes) and LAT2 (microglia). Our glial cell type-level transcriptome analysis unearthed unique molecular pathways and prognostic markers in PTEN status-dependent GBM patients.

FDFT1 maintains glioblastoma stem cells through activation of the Akt pathway

BACKGROUND

Cancer stem cells (CSCs) have unique metabolic characteristics and are hypothesized to contribute significantly to the recurrence and drug resistance of glioblastoma multiforme (GBM). However, the reliance on mitochondrial metabolism and the underlying mechanism of glioblastoma stem cells (GSCs) remains to be elucidated.

METHODS

To quantify differential mitochondrial protein expression between GSCs and differentiated cells, a mass spectrum screen was applied by the Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) technique. Functional experiments including CCK8, neurosphere formation, flow cytometry, transwell, and wound healing assays were conducted to evaluate GBM cell malignant phenotype. The potential molecular mechanism of FDFT1 was screened by RNA-seq analyses. The candidate target genes were validated through RT-qPCR and western blot analyses.

RESULTS

As a top candidate, FDFT1 protein expression in GSCs was elevated relative to their differentiated counterparts. Functionally, the knockdown of FDFT1 suppressed the GBM cell proliferation and migration, while simultaneously enhancing sensitivity to temozolomide. Treatment with both the FDFT1 inhibitor (YM-53601) and simvastatin (an HMG-CoA reductase inhibitor) induced apoptosis in GSCs. Mechanistically, FDFT1 was transcriptionally regulated by SREBP2 but not SREBP1. Furthermore, FDFT1 activates the AKT pathway to regulate tumor metabolism and maintain the stemness of tumor cells.

CONCLUSIONS

GSCs exhibit a dependency on FDFT1-mediated mevalonate metabolism. Inhibition of FDFT1 could represent a potent strategy to eliminate GSCs.

Repurposing the antipsychotic drug penfluridol for cancer treatment (Review)

Cancer is one of the most prevalent diseases and the leading cause of death worldwide. Despite the improved survival rates of cancer in recent years, the current available treatments often face resistance and side effects. Drug repurposing represents a cost‑effective and efficient alternative to cancer treatment. Recent studies revealed that penfluridol (PF), an antipsychotic drug, is a promising anticancer agent. In the present study, a scoping review was conducted to ascertain the anticancer properties of PF. For this, a literature search was performed using the Scopus, PubMed and Web of Science databases with the search string 'penfluridol' AND 'cancer'. A total of 23 original articles with in vivo and/or in vitro studies on the effect of PF on cancer were included in the scoping review. The outcome of the analysis demonstrated the anticancer potential of PF. PF significantly inhibited cell proliferation, metastasis and invasion while inducing apoptosis and autophagy in vivo and across a spectrum of cancer cell lines, including breast, lung, pancreatic, glioblastoma, gallbladder, bladder, oesophageal, leukaemia and renal cancers. However, research on PF derivatives with high anticancer activities and reduced neurological side effects may be necessary.

Cepharanthine as an effective small cell lung cancer inhibitor: integrated insights from network pharmacology, RNA sequencing, and experimental validation

Background

Small cell lung cancer (SCLC) is an aggressive malignancy with limited treatment options and poor prognosis, underscoring the need for new therapeutic agents.

Methods

A library of 640 natural products was screened for anti-proliferative activity in SCLC cells. The effects of Cepharanthine (CE) on SCLC cells were assessed in vitro and in vivo. Network pharmacology and RNA sequencing (RNA-seq) were used to elucidate the molecular mechanisms. Pathway enrichment analysis was performed using Gene Set Enrichment Analysis (GSEA) with Hallmark and Reactome gene sets. Protein-protein interaction (PPI) networks, along with the Cytoscape cytoHubba plugin, were used to identify key hub genes. RT-PCR and Western blotting were employed to validate mRNA and protein expression. Molecular docking studies assessed the binding affinity of CE to potential targets. Bioinformatics analyses, including expression profiling, prognostic evaluation, and loss-of-function studies, were used to explore the role of specific genes in SCLC.

Results

CE was identified as a promising SCLC inhibitor. In vitro, CE significantly inhibited SCLC cell proliferation, colony formation, migration, and invasion, while promoting apoptosis. In vivo, CE treatment notably reduced tumor volume in xenograft models. Network pharmacology identified 60 potential target genes, with enrichment analysis indicating their involvement in cholesterol metabolism regulation. RNA-seq and experimental validation further confirmed that CE inhibits cholesterol synthesis in SCLC cells by downregulating key enzymes, including HMGCR, HMGCS1, IDI1, FDFT1, and SQLE. Molecular docking studies confirmed the binding of CE to these enzymes. Additionally, these enzymes were found to be highly expressed in SCLC cells, with elevated levels of HMGCS1, HMGCR, and IDI1 correlating with poor prognosis. Functional assays revealed that silencing these genes significantly suppressed SCLC cell proliferation.

Conclusion

This study identifies CE as a potential therapeutic agent for SCLC, acting through the suppression of cholesterol synthesis, and uncovers novel therapeutic targets for the treatment of this aggressive cancer.

Evaluating pathological levels of intracellular cholesterol through Raman and surface-enhanced Raman spectroscopies

Versatile methods for the quantification of intracellular cholesterol are essential for understanding cellular physiology and for diagnosing disorders linked to cholesterol metabolism. Here we used Raman spectroscopy (RS) and surface-enhanced Raman spectroscopy (SERS) to measure changes in cholesterol after incubating human fibroblasts with increasing concentrations of cholesterol-methyl-β-cyclodextrin. RS and SERS were sensitive and accurate enough to detect high levels of cholesterol in fibroblasts from patients affected by type C Niemann-Pick disease (NPC), a lysosomal storage disorder characterized by the primary accumulation of cholesterol. Moreover, SERS was able to distinguish between fibroblasts from different NPC patients, demonstrating higher accuracy than RS and standard fluorescent labeling of cholesterol with filipin III. We show that the type of gold nanoparticles used as signal enhancer surfaces in our SERS measurements are internalized by the cells and are eventually found in lysosomes, the main site of accumulation of cholesterol in NPC fibroblasts. The higher sensitivity of SERS can thus be attributed to the specific trafficking of our gold nanoparticles into these organelles. Our results indicate that RS and SERS can be used as sensitive and accurate methods for the evaluation of intracellular cholesterol content, allowing for the potential development of an optical detection tool for the ex-vivo screening and monitoring of those diseases characterized by abnormal modification in cholesterol levels.

SQLE-a promising prognostic biomarker in cervical cancer: implications for tumor malignant behavior, cholesterol synthesis, epithelial-mesenchymal transition, and immune infiltration

BACKGROUND

Cervical cancer, encompassing squamous cell carcinoma and endocervical adenocarcinoma (CESC), presents a considerable risk to the well-being of women. Recent studies have reported that squalene epoxidase (SQLE) is overexpressed in several cancers, which contributes to cancer development.

METHODS

RNA sequencing data for SQLE were obtained from The Cancer Genome Atlas. In vitro experiments, including colorimetry, colony formation, Transwell, RT-qPCR, and Western blotting were performed. Furthermore, a transplanted CESC nude mouse model was constructed to validate the tumorigenic activity of SQLE in vivo. Associations among the SQLE expression profiles, differentially expressed genes (DEGs), immune infiltration, and chemosensitivity were examined. The prognostic value of genetic changes and DNA methylation in SQLE were also assessed.

RESULTS

SQLE mRNA expression was significantly increased in CESC. ROC analysis revealed the strong diagnostic ability of SQLE toward CESC. Patients with high SQLE expression experienced shorter overall survival. The promotional effects of SQLE on cancer cell proliferation, metastasis, cholesterol synthesis, and EMT were emphasized. DEGs functional enrichment analysis revealed the signaling pathways and biological processes. Notably, a connection existed between the SQLE expression and the presence of immune cells as well as the activation of immune checkpoints. Increased SQLE expressions exhibited increased chemotherapeutic responses. SQLE methylation status was significantly associated with CESC prognosis.

CONCLUSION

SQLE significantly affects CESC prognosis, malignant behavior, cholesterol synthesis, EMT, and immune infiltration; thereby offering diagnostic and indicator roles in CESC. Thus, SQLE can be a novel therapeutic target in CESC treatment.

Recommended and observed statin use among US adults with and without cancer

AIMS

Patients with cancer are at increased cardiovascular (CV) risk. We aimed to compare the recommended and observed statin use among individuals with and without cancer.

METHODS AND RESULTS

Using three 2-year cycles from the National Health and Nutrition Examination Survey (2013-18), we analysed data from 17 050 US adults. We compared the prevalence of Class 1 statin recommendations and use between individuals with and without cancer, overall, and among different demographic groups. Individuals with a history of cancer were older and had a higher burden of comorbidities. Stratified by age groups, they were more likely to have a secondary prevention indication compared with individuals without cancer but not a primary prevention indication for statin. Among individuals with an indication for statin therapy, the prevalence of statin use was higher in the cancer group compared with those without cancer (60.8% vs. 47.8%, P < 0.001), regardless of sex, type of indication (primary vs. secondary prevention), and education level. However, the higher prevalence of statin use in the cancer group was noted among younger individuals, ethnic minorities, and those with lower family income.

CONCLUSION

Our finding highlights the importance of optimization of CV health in patients with cancer, as individuals with cancer were more likely to have a Class 1 indication for statin treatment when compared with individuals without cancer. Important differences in statin use among cohorts based on sex, age, ethnicity, and socioeconomic status were identified, which may provide a framework through which CV risk factor control can be targeted in this population.

KEY FINDINGS

Higher statin use in cancer patients: Among those with Class 1 recommendation to take statins, 60.8% of cancer patients were using them, compared with 47.8% of non-cancer individuals, indicating a greater adherence to heart health recommendations in the cancer group. Demographic variations in statin use: The study found notable differences in statin use among younger individuals, ethnic minorities, and those with lower income within the cancer patient group, suggesting disparities in how these subgroups manage their cardiovascular health.

Emerging mechanisms and promising approaches in pancreatic cancer metabolism

Pancreatic cancer is an aggressive cancer with a poor prognosis. Metabolic abnormalities are one of the hallmarks of pancreatic cancer, and pancreatic cancer cells can adapt to biosynthesis, energy intake, and redox needs through metabolic reprogramming to tolerate nutrient deficiency and hypoxic microenvironments. Pancreatic cancer cells can use glucose, amino acids, and lipids as energy to maintain malignant growth. Moreover, they also metabolically interact with cells in the tumour microenvironment to change cell fate, promote tumour progression, and even affect immune responses. Importantly, metabolic changes at the body level deserve more attention. Basic research and clinical trials based on targeted metabolic therapy or in combination with other treatments are in full swing. A more comprehensive and in-depth understanding of the metabolic regulation of pancreatic cancer cells will not only enrich the understanding of the mechanisms of disease progression but also provide inspiration for new diagnostic and therapeutic approaches.

Residual OXPHOS is required to drive primary and metastatic lung tumours in an orthotopic breast cancer model

Background

Fast adaptation of glycolytic and mitochondrial energy pathways to changes in the tumour microenvironment is a hallmark of cancer. Purely glycolytic ρ0 tumour cells do not form primary tumours unless they acquire healthy mitochondria from their micro-environment. Here we explored the effects of severely compromised respiration on the metastatic capability of 4T1 mouse breast cancer cells.

Methods

4T1 cell lines with different levels of respiratory capacity were generated; the Seahorse extracellular flux analyser was used to evaluate oxygen consumption rates, fluorescent confocal microscopy to assess the number of SYBR gold-stained mitochondrial DNA nucleoids, and the presence of the ATP5B protein in the cytoplasm and fluorescent in situ nuclear hybridization was used to establish ploidy. MinION nanopore RNA sequence analysis was used to compare mitochondrial DNA transcription between cell lines. Orthotopic injection was used to determine the ability of cells to metastasize to the lungs of female Balb/c mice.

Results

OXPHOS-deficient ATP5B-KO3.1 cells did not generate primary tumours. Severely OXPHOS compromised ρ0D5 cells generated both primary tumours and lung metastases. Cells generated from lung metastasis of both OXPHOS-competent and OXPHOS-compromised cells formed primary tumours but no metastases when re-injected into mice. OXPHOS-compromised cells significantly increased their mtDNA content, but this did not result in increased OXPHOS capacity, which was not due to decreased mtDNA transcription. Gene set enrichment analysis suggests that certain cells derived from lung metastases downregulate their epithelial-to-mesenchymal related pathways.

Conclusion

In summary, OXPHOS is required for tumorigenesis in this orthotopic mouse breast cancer model but even very low levels of OXPHOS are sufficient to generate both primary tumours and lung metastases.

Drug repurposing for cancer therapy

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.