CD36 mediates palmitate acid-induced metastasis of gastric cancer via AKT/GSK-3β/β-catenin pathway

Unraveling brain palmitic acid: Origin, levels and metabolic fate

In the human brain, palmitic acid (16:0; PAM) comprises nearly half of total brain saturates and has been identified as the third most abundant fatty acid overall. Brain PAM supports the structure of membrane phospholipids, provides energy, and regulates protein stability. Sources underlying the origin of brain PAM are both diet and endogenous synthesis via de novo lipogenesis (DNL), primarily from glucose. However, studies investigating the origin of brain PAM are limited to tracer studies utilizing labelled (14C/11C/3H/2H) PAM, and results vary based on the model and tracer used. Nevertheless, there is evidence PAM is synthesized locally in the brain, in addition to obtained directly from the diet. Herein, we provide an overview of brain PAM origin, entry to the brain, metabolic fate, and factors influencing brain PAM kinetics and levels, the latter in the context of age, as well as neurological diseases and psychiatric disorders. Additionally, we briefly summarize the role of PAM in signaling at the level of the brain. We add to the literature a rudimentary summary on brain PAM metabolism.

A novel M2-like tumor associated macrophages-related gene signature for predicting the prognosis and immunotherapy efficacy in gastric cancer

BACKGROUND

M2-like tumor-associated macrophages (M2-like TAMs) play key roles in tumor progression and the immune response. However, the clinical significance and prognostic value of M2-like TAMs-associated regulatory genes in gastric cancer (GC) have not been clarified.

METHODS

Herein, we identified M2-like TAM-related genes by weighted gene coexpression network analysis of TCGA-STAD and GSE84437 cohort. Lasso-Cox regression analyses were then performed to screen for signature genes, and a novel signature was constructed to quantify the risk score for each patient. Tumor mutation burden (TMB), survival outcomes, immune cells, and immune function were analyzed in the risk groups to further reveal the immune status of GC patients. A gene-drug correlation analysis and sensitivity analysis of anticancer drugs were used to identify potential therapeutic agents. Finally, we verified the mRNA expression of signature genes in patient tissues by qRT-PCR, and analyzed the expression distribution of these genes by IHC.

RESULTS

A 4-gene (SERPINE1, MATN3, CD36, and CNTN1) signature was developed and validated, and the risk score was shown to be an independent prognostic factor for GC patients. Further analyses revealed that GC patients in the high-risk group had a worse prognosis than those in the low-risk group, with significant differences in TMB, clinical features, enriched pathways, TIDE score, and tumor microenvironment features. Finally, we used qRT-PCR and IHC analysis to verify mRNA and protein level expression of signature genes.

CONCLUSION

These findings highlight the importance of M2-like TAMs, provide a new perspective on individualized immunotherapy for GC patients.

CD36: a promising therapeutic target in hematologic tumors

Cluster of differentiation 36 (CD36) is a multiligand receptor with important roles in lipid metabolism, angiogenesis and innate immunity, and its diverse effects may depend on the binding of specific ligands in different contexts. CD36 is expressed not only on immune cells in the tumor microenvironment (TME) but also on some hematopoietic cells. CD36 is associated with the growth, metastasis and drug resistance in some hematologic tumors, such as leukemia, lymphoma and myelodysplastic syndrome. Currently, some targeted therapeutic agents against CD36 have been developed, such as anti-CD36 antibodies, CD36 antagonists (small molecules) and CD36 expression inhibitors. This paper not only innovatively addresses the role of CD36 in some hematopoietic cells, such as erythrocytes, hematopoietic stem cells and platelets, but also pays special attention to the role of CD36 in the development of hematologic tumors, and suggests that CD36 may be a potential cancer therapeutic target in hematologic tumors.

Dissecting gastric cancer heterogeneity and exploring therapeutic strategies using bulk and single-cell transcriptomic analysis and experimental validation of tumor microenvironment and metabolic interplay

Gastric cancer, the fifth most prevalent cancer worldwide, is often diagnosed in advanced stages with limited treatment options. Examining the tumor microenvironment (TME) and its metabolic reprogramming can provide insights for better diagnosis and treatment. This study investigates the link between TME factors and metabolic activity in gastric cancer using bulk and single-cell RNA-sequencing data. We identified two molecular subtypes in gastric cancer by analyzing the distinct expression patterns of 81 prognostic genes related to the TME and metabolism, which exhibited significant protein-level interactions. The high-risk subtype had increased stromal content, fibroblast and M2 macrophage infiltration, elevated glycosaminoglycans/glycosphingolipids biosynthesis, and fat metabolism, along with advanced clinicopathological features. It also exhibited low mutation rates and microsatellite instability, associating it with the mesenchymal phenotype. In contrast, the low-risk group showed higher tumor content and upregulated protein and sugar metabolism. We identified a 15-gene prognostic signature representing these characteristics, including CPVL, KYNU, CD36, and GPX3, strongly correlated with M2 macrophages, validated through single-cell analysis and an internal cohort. Despite resistance to immunotherapy, the high-risk group showed sensitivity to molecular targeted agents directed at IGF-1R (BMS-754807) and the PI3K-mTOR pathways (AZD8186, AZD8055). We experimentally validated these promising drugs for their inhibitory effects on MKN45 and MKN28 gastric cells. This study unveils the intricate interplay between TME and metabolic pathways in gastric cancer, offering potential for enhanced diagnosis, patient stratification, and personalized treatment. Understanding molecular features in each subtype enriches our comprehension of gastric cancer heterogeneity and potential therapeutic targets.

Pathomics and single-cell analysis of papillary thyroid carcinoma reveal the pro-metastatic influence of cancer-associated fibroblasts

BACKGROUND

Papillary thyroid carcinoma (PTC) is globally prevalent and associated with an increased risk of lymph node metastasis (LNM). The role of cancer-associated fibroblasts (CAFs) in PTC remains unclear.

METHODS

We collected postoperative pathological hematoxylin-eosin (HE) slides from 984 included patients with PTC to analyze the density of CAF infiltration at the invasive front of the tumor using QuPath software. The relationship between CAF density and LNM was assessed. Single-cell RNA sequencing (scRNA-seq) data from GSE193581 and GSE184362 datasets were integrated to analyze CAF infiltration in PTC. A comprehensive suite of in vitro experiments, encompassing EdU labeling, wound scratch assays, Transwell assays, and flow cytometry, were conducted to elucidate the regulatory role of CD36+CAF in two PTC cell lines, TPC1 and K1.

RESULTS

A significant correlation was observed between high fibrosis density at the invasive front of the tumor and LNM. Analysis of scRNA-seq data revealed metastasis-associated myoCAFs with robust intercellular interactions. A diagnostic model based on metastasis-associated myoCAF genes was established and refined through deep learning methods. CD36 positive expression in CAFs can significantly promote the proliferation, migration, and invasion abilities of PTC cells, while inhibiting the apoptosis of PTC cells.

CONCLUSION

This study addresses the significant issue of LNM risk in PTC. Analysis of postoperative HE pathological slides from a substantial patient cohort reveals a notable association between high fibrosis density at the invasive front of the tumor and LNM. Integration of scRNA-seq data comprehensively analyzes CAF infiltration in PTC, identifying metastasis-associated myoCAFs with strong intercellular interactions. In vitro experimental results indicate that CD36 positive expression in CAFs plays a promoting role in the progression of PTC. Overall, these findings provide crucial insights into the function of CAF subset in PTC metastasis.

High-fat diet promotes liver tumorigenesis via palmitoylation and activation of AKT

OBJECTIVE

Whether and how the PI3K-AKT pathway, a central node of metabolic homeostasis, is responsible for high-fat-induced non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) remain a mystery. Characterisation of AKT regulation in this setting will provide new strategies to combat HCC.

DESIGN

Metabolite library screening disclosed that palmitic acid (PA) could activate AKT. In vivo and in vitro palmitoylation assay were employed to detect AKT palmitoylation. Diverse cell and mouse models, including generation of AKT1C77S and AKT1C224S knock-in cells, Zdhhc17 and Zdhhc24 knockout mice and Akt1C224S knock-in mice were employed. Human liver tissues from patients with NASH and HCC, hydrodynamic transfection mouse model, high-fat/high-cholesterol diet (HFHCD)-induced NASH/HCC mouse model and high-fat and methionine/choline-deficient diet (HFMCD)-induced NASH mouse model were also further explored for our mechanism studies.

RESULTS

By screening a metabolite library, PA has been defined to activate AKT by promoting its palmitoyl modification, an essential step for growth factor-induced AKT activation. Biologically, a high-fat diet could promote AKT kinase activity, thereby promoting NASH and liver cancer. Mechanistically, palmitoyl binding anchors AKT to the cell membrane in a PIP3-independent manner, in part by preventing AKT from assembling into an inactive polymer. The palmitoyltransferases ZDHHC17/24 were characterised to palmitoylate AKT to exert oncogenic effects. Interestingly, the anti-obesity drug orlistat or specific penetrating peptides can effectively attenuate AKT palmitoylation and activation by restricting PA synthesis or repressing AKT modification, respectively, thereby antagonising liver tumorigenesis.

CONCLUSIONS

Our findings elucidate a novel fine-tuned regulation of AKT by PA-ZDHHC17/24-mediated palmitoylation, and highlight tumour therapeutic strategies by taking PA-restricted diets, limiting PA synthesis, or directly targeting AKT palmitoylation.

Metabolic heterogeneity in tumor microenvironment - A novel landmark for immunotherapy

The surrounding non-cancer cells and tumor cells that make up the tumor microenvironment (TME) have various metabolic rhythms. TME metabolic heterogeneity is influenced by the intricate network of metabolic control within and between cells. DNA, protein, transport, and microbial levels are important regulators of TME metabolic homeostasis. The effectiveness of immunotherapy is also closely correlated with alterations in TME metabolism. The response of a tumor patient to immunotherapy is influenced by a variety of variables, including intracellular metabolic reprogramming, metabolic interaction between cells, ecological changes within and between tumors, and general dietary preferences. Although immunotherapy and targeted therapy have made great strides, their use in the accurate identification and treatment of tumors still has several limitations. The function of TME metabolic heterogeneity in tumor immunotherapy is summarized in this article. It focuses on how metabolic heterogeneity develops and is regulated as a tumor progresses, the precise molecular mechanisms and potential clinical significance of imbalances in intracellular metabolic homeostasis and intercellular metabolic coupling and interaction, as well as the benefits and drawbacks of targeted metabolism used in conjunction with immunotherapy. This offers insightful knowledge and important implications for individualized tumor patient diagnosis and treatment plans in the future.

Emerging targets in lipid metabolism for cancer therapy

Cancer cells perturb lipid metabolic pathways for a variety of pro-tumorigenic functions, and deregulated cellular metabolism is a hallmark of cancer cells. Although alterations in lipid metabolism in cancer cells have been appreciated for over 20 years, there are no FDA-approved cancer treatments that target lipid-related pathways. Recent advances pertaining to cancer cell fatty acid synthesis (FAS), desaturation, and uptake, microenvironmental and dietary lipids, and lipid metabolism of tumor-infiltrating immune cells have illuminated promising clinical applications for targeting lipid metabolism. This review highlights emerging pathways and targets for tumor lipid metabolism that may soon impact clinical treatment.

The function of CD36 in Mycobacterium tuberculosis infection

CD36 is a scavenger receptor that has been reported to function as a signaling receptor that responds to pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) and could integrate metabolic pathways and cell signaling through its dual functions. Thereby influencing activation to regulate the immune response and immune cell differentiation. Recent studies have revealed that CD36 plays critical roles in the process of lipid metabolism, inflammatory response and immune process caused by Mycobacterium tuberculosis infection. This review will comprehensively investigate CD36's functions in lipid uptake and processing, inflammatory response, immune response and therapeutic targets and biomarkers in the infection process of M. tuberculosis. The study also raised outstanding issues in this field to designate future directions.

Palmitic Acid Exerts Anti-Tumorigenic Activities by Modulating Cellular Stress and Lipid Droplet Formation in Endometrial Cancer

Epidemiological and clinical evidence have extensively documented the role of obesity in the development of endometrial cancer. However, the effect of fatty acids on cell growth in endometrial cancer has not been widely studied. Here, we reported that palmitic acid significantly inhibited cell proliferation of endometrial cancer cells and primary cultures of endometrial cancer and reduced tumor growth in a transgenic mouse model of endometrial cancer, in parallel with increased cellular stress and apoptosis and decreased cellular adhesion and invasion. Inhibition of cellular stress by N-acetyl-L-cysteine effectively reversed the effects of palmitic acid on cell proliferation, apoptosis, and invasive capacity in endometrial cancer cells. Palmitic acid increased the intracellular formation of lipid droplets in a time- and dose-dependent manner. Depletion of lipid droplets by blocking DGAT1 and DGAT2 effectively increased the ability of palmitic acid to inhibit cell proliferation and induce cleaved caspase 3 activity. Collectively, this study provides new insight into the effect of palmitic acid on cell proliferation and invasion and the formation of lipid droplets that may have potential clinical relevance in the treatment of obesity-driven endometrial cancer.

Targeting lipid reprogramming in the tumor microenvironment by traditional Chinese medicines as a potential cancer treatment

In the last ten years, there has been a notable rise in the study of metabolic abnormalities in cancer cells. However, compared to glucose or glutamine metabolism, less attention has been paid to the importance of lipid metabolism in tumorigenesis. Recent developments in lipidomics technologies have allowed for detailed analysis of lipid profiles within cancer cells and other cellular players present within the tumor microenvironment (TME). Traditional Chinese medicine (TCM) and its bioactive components have a long history of use in cancer treatments and are also being studied for their potential role in regulating metabolic reprogramming within TME. This review focuses on four core abnormalities altered by lipid reprogramming in cancer cells: de novo synthesis and exogenous uptake of fatty acids (FAs), upregulated fatty acid oxidation (FAO), cholesterol accumulation, which offer benefits for tumor growth and metastasis. The review also discusses how altered lipid metabolism impacts infiltrating immune cell function and phenotype as these interactions between cancer-stromal become more pronounced during tumor progression. Finally, recent literature is highlighted regarding how cancer cells can be metabolically reprogrammed by specific Chinese herbal components with potential therapeutic benefits related to lipid metabolic and signaling pathways.

DAMPs and DAMP-sensing receptors in inflammation and diseases

Damage-associated molecular patterns (DAMPs) are endogenous danger molecules produced in cellular damage or stress, and they can activate the innate immune system. DAMPs contain multiple types of molecules, including nucleic acids, proteins, ions, glycans, and metabolites. Although these endogenous molecules do not trigger immune response under steady-state condition, they may undergo changes in distribution, physical or chemical property, or concentration upon cellular damage or stress, and then they become DAMPs that can be sensed by innate immune receptors to induce inflammatory response. Thus, DAMPs play an important role in inflammation and inflammatory diseases. In this review, we summarize the conversion of homeostatic molecules into DAMPs; the diverse nature and classification, cellular origin, and sensing of DAMPs; and their role in inflammation and related diseases. Furthermore, we discuss the clinical strategies to treat DAMP-associated diseases via targeting DAMP-sensing receptors.

Cancer-associated fibroblasts contributed to hepatocellular carcinoma recurrence and metastasis via CD36-mediated fatty-acid metabolic reprogramming

Cancer-associated fibroblasts (CAFs) are the main components in the tumor microenvironment. Tumors activate fibroblasts from quiescent state into activated state by secreting cytokines, and activated CAFs may in turn promote tumor progression and metastasis. Therefore, studies targeting CAFs could enrich the therapeutic options for tumor treatment. In this study, we demonstrate that the content of lipid droplets and the expression of autophagosomes were higher in CAFs than in peri-tumor fibroblasts (PTFs), which was inhibited by 5-(tetradecyloxy)-2-furoic acid(TOFA). The expression of CD36 in CAFs was higher than that in PTFs at both mRNA and protein levels. Inhibition of CD36 activity using either the CD36 inhibitor SSO or siRNA had a significant negative impact on the proliferation and migration abilities of CAFs, which was associated with reduced levels of relevant activated genes (α-SMA, FAP, Vimentin) and cytokines (IL-6, TGF-β and VEGF-α). SSO also inhibited HCC growth and tumorigenesis in nude mice orthotopically implanted with CAFs and HCC cells. Our data further show that CD36+CAFs affected the expression of PD-1 in CTLs leading to CTL exhaustion, and that patients with high CD36 expression in CAFs were correlated with shorter overall survival (OS). Together, our data demonstrate that CAFs were active in lipid metabolism with increased lipid content and lipophagy activity. CD36 may play a key role in the regulation of the biological behaviors of CAFs, which may influence the proliferation and migration of tumor cells by reprograming the lipid metabolism in tumor cells. Thus, CD36 could be an effective therapeutic target for the treatment of HCC.

CD36 inhibition reduces non-small-cell lung cancer development through AKT-mTOR pathway

Lung cancer is the most common cause of cancer-related deaths worldwide and is caused by multiple factors, including high-fat diet (HFD). CD36, a fatty acid receptor, is closely associated with metabolism-related diseases, including cardiovascular disease and cancer. However, the role of CD36 in HFD-accelerated non-small-cell lung cancer (NSCLC) is unclear. In vivo, we fed C57BL/6J wild-type (WT) and CD36 knockout (CD36-/-) mice normal chow or HFD in the presence or absence of pitavastatin 2 weeks before subcutaneous injection of LLC1 cells. In vitro, A549 and NCI-H520 cells were treated with free fatty acids (FFAs) to mimic HFD situation for exploration the underlying mechanisms. We found that HFD promoted LLC1 tumor growth in vivo and that FFAs increased cell proliferation and migration in A549 and NCI-H520 cells. The enhanced cell or tumor growth was inhibited by the lipid-lowering agent pitavastatin, which reduced lipid accumulation. More importantly, we found that plasma soluble CD36 (sCD36) levels were higher in NSCLC patients than those in healthy ones. Compared to that in WT mice, the proliferation of LLC1 cells in CD36-/- mice was largely suppressed, which was further repressed by pitavastatin in HFD group. At the molecular level, we found that CD36 inhibition, either with pitavastatin or plasmid, reduced proliferation- and migration-related protein expression through the AKT/mTOR pathway. Taken together, we demonstrate that inhibition of CD36 expression by pitavastatin or other inhibitors may be a viable strategy for NSCLC treatment.

Stroma AReactive Invasion Front Areas (SARIFA) improves prognostic risk stratification of perioperative chemotherapy treated oesophagogastric cancer patients from the MAGIC and the ST03 trial

BACKGROUND

Tumour-associated fat cells without desmoplastic stroma reaction at the invasion front (Stroma AReactive Invasion Front Areas (SARIFA)) is a prognostic biomarker in gastric and colon cancer. The clinical utility of the SARIFA status in oesophagogastric cancer patients treated with perioperative chemotherapy is currently unknown.

METHODS

The SARIFA status was determined in tissue sections from patients recruited into the MAGIC (n = 292) or ST03 (n = 693) trials treated with surgery alone (S, MAGIC) or perioperative chemotherapy (MAGIC, ST03). The relationship between SARIFA status, clinicopathological factors, overall survival (OS) and treatment was analysed.

RESULTS

The SARIFA status was positive in 42% MAGIC trial S patients, 28% MAGIC and 48% ST03 patients after pre-operative chemotherapy. SARIFA status was related to OS in MAGIC trial S patients and was an independent prognostic biomarker in ST03 trial patients (HR 1.974, 95% CI 1.555-2.507, p < 0.001). ST03 patients with lymph node metastasis (ypN + ) and SARIFA-positive tumours had poorer OS than patients with ypN+ and SARIFA-negative tumours (plogrank < 0.001).

CONCLUSIONS

The SARIFA status has clinical utility as prognostic biomarker in oesophagogastric cancer patients irrespective of treatment modality. Whilst underlying biological mechanisms warrant further investigation, the SARIFA status might be used to identify new drug targets, potentially enabling repurposing of existing drugs targeting lipid metabolism.

CD36 as a double-edged sword in cancer

The membrane protein CD36 is a lipid transporter, scavenger receptor, and receptor for the antiangiogenic protein thrombospondin 1 (TSP1). CD36 is expressed by cancer cells and by many associated cells including various cancer-infiltrating immune cell types. Thereby, CD36 plays critical roles in cancer, and it has been reported to affect cancer growth, metastasis, angiogenesis, and drug resistance. However, these roles are partly contradictory, as CD36 has been both reported to promote and inhibit cancer progression. Moreover, the mechanisms are also partly contradictory, because CD36 has been shown to exert opposite cellular effects such as cell division, senescence and cell death. This review provides an overview of the diverse effects of CD36 on tumor progression, aiming to shed light on its diverse pro- and anti-cancer roles, and the implications for therapeutic targeting.

Inside anticancer therapy resistance and metastasis. Focus on CD36

Despite recent advances in targeted cancer therapies, drug resistance remains an important setback in tumor control. Understanding the complex mechanisms involved in both innate and acquired drug resistance represents the first step in discovering novel therapeutic agents. Because of its importance in tumorigenesis, progression, and metastasis, lipid metabolism is increasingly garnering attention. CD36 is a membrane receptor at the top of the signaling cascade that transports lipids. Its expression has been repeatedly presented as an unfavorable prognostic factor for various tumor types, raising the question: could CD36 be a critical factor in cancer treatment resistance? In our review, we set out to explore the most prominent studies on the implication of CD36 in resistance to platinum-based drugs and other adjuvant cancer therapies in solid and haematological neoplasia. Moreover, we provide an overview of the latest anti-CD36 cancer therapies, thus opening new perspectives for future personalized medicine.

Proteomic, Metabolomic, and Fatty Acid Profiling of Small Extracellular Vesicles from Glioblastoma Stem-Like Cells and Their Role in Tumor Heterogeneity

Glioblastoma is a deadly brain tumor for which there is no cure. The presence of glioblastoma stem-like cells (GSCs) contributes to the heterogeneous nature of the disease and makes developing effective therapies challenging. Glioblastoma cells have been shown to influence their environment by releasing biological nanostructures known as extracellular vesicles (EVs). Here, we investigated the role of GSC-derived nanosized EVs (<200 nm) in glioblastoma heterogeneity, plasticity, and aggressiveness, with a particular focus on their protein, metabolite, and fatty acid content. We showed that conditioned medium and small extracellular vesicles (sEVs) derived from cells of one glioblastoma subtype induced transcriptomic and proteomic changes in cells of another subtype. We found that GSC-derived sEVs are enriched in proteins playing a role in the transmembrane transport of amino acids, carboxylic acids, and organic acids, growth factor binding, and metabolites associated with amino acid, carboxylic acid, and sugar metabolism. This suggests a dual role of GSC-derived sEVs in supplying neighboring GSCs with valuable metabolites and proteins responsible for their transport. Moreover, GSC-derived sEVs were enriched in saturated fatty acids, while their respective cells were high in unsaturated fatty acids, supporting that the loading of biological cargos into sEVs is a highly regulated process and that GSC-derived sEVs could be sources of saturated fatty acids for the maintenance of glioblastoma cell metabolism. Interestingly, sEVs isolated from GSCs of the proneural and mesenchymal subtypes are enriched in specific sets of proteins, metabolites, and fatty acids, suggesting a molecular collaboration between transcriptionally different glioblastoma cells. In summary, this study revealed the complexity of GSC-derived sEVs and unveiled their potential contribution to tumor heterogeneity and critical cellular processes commonly deregulated in glioblastoma.

CD36: The Bridge between Lipids and Tumors

It has been found that the development of some cancers can be attributed to obesity, which is associated with the excessive intake of lipids. Cancer cells undergo metabolic reprogramming, shifting from utilizing glucose to fatty acids (FAs) for energy. CD36, a lipid transporter, is highly expressed in certain kinds of cancer cells. High expressions of CD36 in tumor cells triggers FA uptake and lipid accumulation, promoting rapid tumor growth and initiating metastasis. Meanwhile, immune cells in the tumor microenvironment overexpress CD36 and undergo metabolic reprogramming. CD36-mediated FA uptake leads to lipid accumulation and has immunosuppressive effects. This paper reviews the types of FAs associated with cancer, high expressions of CD36 that promote cancer development and progression, effects of CD36 on different immune cells in the tumor microenvironment, and the current status of CD36 as a therapeutic target for the treatment of tumors with high CD36 expression.

Obesity, Dietary Fats, and Gastrointestinal Cancer Risk-Potential Mechanisms Relating to Lipid Metabolism and Inflammation

Obesity is a major driving factor in the incidence, progression, and poor treatment response in gastrointestinal cancers. Herein, we conducted a comprehensive analysis of the impact of obesity and its resulting metabolic perturbations across four gastrointestinal cancer types, namely, oesophageal, gastric, liver, and colorectal cancer. Importantly, not all obese phenotypes are equal. Obese adipose tissue heterogeneity depends on the location, structure, cellular profile (including resident immune cell populations), and dietary fatty acid intake. We discuss whether adipose heterogeneity impacts the tumorigenic environment. Dietary fat quality, in particular saturated fatty acids, promotes a hypertrophic, pro-inflammatory adipose profile, in contrast to monounsaturated fatty acids, resulting in a hyperplastic, less inflammatory adipose phenotype. The purpose of this review is to examine the impact of obesity, including dietary fat quality, on adipose tissue biology and oncogenesis, specifically focusing on lipid metabolism and inflammatory mechanisms. This is achieved with a particular focus on gastrointestinal cancers as exemplar models of obesity-associated cancers.

Stroma AReactive Invasion Front Areas (SARIFA) proves prognostic relevance in gastric carcinoma and is based on a tumor-adipocyte interaction indicating an altered immune response

BACKGROUND

Recently, we presented Stroma AReactive Invasion Front Areas (SARIFA) as a new histomorphologic negative prognostic biomarker in gastric cancer. It is defined as direct contact between tumor cells and fat cells. The aim of this study was to further elucidate the underlying genomic, transcriptional, and immunological mechanisms of the SARIFA phenomenon.

METHODS

To address these questions, SARIFA was classified on H&E-stained tissue sections of three cohorts: an external cohort (n = 489, prognostic validation), the TCGA-STAD cohort (n = 194, genomic and transcriptomic analysis), and a local cohort (n = 60, digital spatial profiling (whole transcriptome) and double RNA in situ hybridization/immunostaining of cytokines).

RESULTS

SARIFA status proved to be an independent negative prognostic factor for overall survival in an external cohort of gastric carcinomas. In TCGA-STAD cohort, SARIFA is not driven by distinct genomic alterations, whereas the gene expression analyses showed an upregulation of FABP4 in SARIFA-positive tumors. In addition, the transcriptional regulations of white adipocyte differentiation, triglyceride metabolism, and catabolism were upregulated in pathway analyses. In the DSP analysis of SARIFA-positive tumors, FABP4 and the transcriptional regulation of white adipocyte differentiation were upregulated in macrophages. Additionally, a significantly lower expression of the cytokines IL6 and TNFα was observed at the invasion front.

CONCLUSIONS

SARIFA proves to be a strong negative prognostic biomarker in advanced gastric cancer, implicating an interaction of tumor cells with tumor-promoting adipocytes with crucial changes in tumor cell metabolism. SARIFA is not driven by tumor genetics but is very likely driven by an altered immune response as a causative mechanism.

A novel prognostic and therapeutic target biomarker based on complement-related gene signature in gastric cancer

Background

Gastric cancer (GC) is one of the most prevalent cancer types that reduce human life expectancy. The current tumor-node-metastasis (TNM) staging system is inadequate in identifying higher or lower risk of GC patients because of tumor heterogeneity. Research shows that complement plays a dual role in the tumor development and progression of GC.

Methods

We downloaded GC data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). A complement-related risk signature was constructed through bioinformatics analysis. Subsequently, the predictive ability of this signature was validated with GSE84437 dataset, and a nomogram integrating risk score and common clinical factors was established. Besides, we evaluated the association of risk score with the immune and stromal cell infiltration in TCGA. Furthermore, immunotherapy response prediction and drug susceptibility analysis were conducted to access the ability of the risk signature in predicting the therapeutic effect.

Results

A complement-related gene (CRG) signature, based on six genes (SPLG, C9, ITIH1, ZFPM2, CD36, and SERPINE1), was established. In both the training and validation sets, the overall survival of GC patients in the high-risk group was lower than that of the low-risk group, and the nomogram to predict the 1-, 2-, and 3-year survival rates of GC patients was developed. In addition, CIBERSORT algorithm showed the high-risk patients had higher levels of immune cell infiltration than low-risk patients, and the ESTIMATE results implied that the high-risk group had more stromal component in tumor microenvironment. Besides, compared to the low-risk group, there were higher expressions of most immune checkpoint genes and HLA genes in the high-risk group, and the high-risk patients showed higher sensitivity to the chemotherapy and targeted drugs (axitinib, dasatinib, pazopanib, saracatinib, sunitinib and temsirolimus).

Conclusions

The novel CRG signature may act as a reliable, efficient tool for prognostic prediction and treatment guidance in future clinical practice.

A review of Glycogen Synthase Kinase-3 (GSK3) inhibitors for cancers therapies

The intricate molecular pathways governing cancer development and progression have spurred intensive investigations into novel therapeutic targets. Glycogen Synthase Kinase-3 (GSK3), a complex serine/threonine kinase, has emerged as a key player with intricate roles in various cellular processes, including cell proliferation, differentiation, apoptosis, and metabolism. Harnessing GSK3 inhibitors as potential candidates for cancer therapy has garnered significant interest due to their ability to modulate key signalling pathways that drive oncogenesis. The review encompasses a thorough examination of the molecular mechanisms underlying GSK3's involvement in cancer progression, shedding light on its interaction with critical pathways such as Wnt/β-catenin, PI3K/AKT, and NF-κB. Through these interactions, GSK3 exerts influence over tumour growth, invasion, angiogenesis, and metastasis, rendering it an attractive target for therapeutic intervention. The discussion includes preclinical and clinical studies, showcasing the inhibitors efficacy across a spectrum of cancer types, including pancreatic, ovarian, lung, and other malignancies. Insights from recent studies highlight the potential synergistic effects of combining GSK3 inhibitors with conventional chemotherapeutic agents or targeted therapies, opening avenues for innovative combinatorial approaches. This review provides a comprehensive overview of the current state of research surrounding GSK3 inhibitors as promising agents for cancer treatment.

Ligand-dependent CD36 functions in cancer progression, metastasis, immune response, and drug resistance

CD36, a multifunctional glycoprotein, has been shown to play critical roles in tumor initiation, progression, metastasis, immune response, and drug resistance. CD36 serves as a receptor for a wide range of ligands, including lipid-related ligands (e.g., long-chain fatty acid (LCFA), oxidized low-density lipoprotein (oxLDL), and oxidized phospholipids), as well as protein-related ligands (e.g., thrombospondins, amyloid proteins, collagens I and IV). CD36 is overexpressed in various cancers and may act as an independent prognostic marker. While it was initially identified as a mediator of anti-angiogenesis through its interaction with thrombospondin-1 (TSP1), recent research has highlighted its role in promoting tumor growth, metastasis, drug resistance, and immune suppression. The varied impact of CD36 on cancer is likely ligand-dependent. Therefore, we focus specifically on the ligand-dependent role of CD36 in cancer to provide a critical review of recent advances, perspectives, and challenges.

Humanized CD36 (hCD36) mouse model supports the preclinical evaluation of therapeutic candidates targeting CD36

CD36 (also known as scavenger receptor B2) is a multifunctional receptor that mediates lipid uptake, advanced oxidation protein products, and immunological recognition, and has roles in lipid accumulation, apoptosis, as well as in metastatic colonization in cancer. CD36 is involved in tumor immunity, metastatic invasion, and therapy resistance through various molecular mechanisms. Targeting CD36 has emerged as an effective strategy for tumor immunotherapy. In this study, we have successfully generated a novel hCD36 mouse (Unless otherwise stated, hCD36 mouse below refer to homozygous hCD36 mouse) strain where the sequences encoding the extracellular domains of the mouse Cd36 gene were replaced with the corresponding human sequences. The results showed that the hCD36 mice only expressed human CD36, and the proportion of each lymphocyte was not significantly changed compared with wild-type mice. Furthermore, CD36 monoclonal antibody could significantly inhibit tumor growth after treatment. Therefore, the hCD36 mouse represent a validated preclinical mouse model for the evaluation of tumor immunotherapy targeting CD36.

Role of Metabolomics in Pathogenesis and Prompt Diagnosis of Gastric Cancer Metastasis-A Systematic Review

INTRODUCTION

Gastric cancer is the fourth most frequently diagnosed form of cancer and the third leading cause of cancer-related mortality worldwide. The aim of this review is to identify individual metabolic biomarkers and their association with accurate diagnostic values, which can predict gastric cancer metastasis.

MATERIALS AND METHODS

After searching the keywords, 83 articles were found over a period of 13 years. One was eliminated because it was not written in English, and two were published outside the selected period. Seven scientific papers were qualified for this investigation after eliminating duplicates, non-related articles, systematic reviews, and restricted access studies.

RESULTS

New metabolic biomarkers with predictive value for gastric cancer metastasis and for elucidating metabolic pathways of the metastatic process have been found. The pathogenic processes can be outlined as follows: pro-oxidant capacity, T-cell inactivation, cell cycle arrest, energy production and mitochondrial enzyme impairment, cell viability and pro-apoptotic effect, enhanced degradation of collagen extracellular matrix, migration, invasion, structural protein synthesis, and tumoral angiogenesis.

CONCLUSION

Metabolic biomarkers have been recognized as independent risk factors in the molecular process of gastric cancer metastasis, with good diagnostic and prognostic value.

CIP2A interacts with AKT1 to promote the malignant biological behaviors of oral squamous cell carcinoma by upregulating the GSK‑3β/β‑catenin pathway

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies worldwide, which is associated with a poor prognosis. The present study aimed to investigate the role of cancerous inhibitor of protein phosphatase 2A (CIP2A) in OSCC and its regulatory effect on AKT1. Firstly, CIP2A and AKT1 expression in OSCC cells was detected by western blotting. After silencing CIP2A, cell viability and cell proliferation were assessed using the Cell Counting Kit-8 assay and 5-ethynyl-2'-deoxyuridine staining. Cell apoptosis was evaluated by TUNEL staining and the expression of apoptosis-related proteins was assessed using western blotting. Wound healing, Transwell and tube formation assays were performed to evaluate CAL-27 cell migration, invasion and human umbilical vein endothelial cell (HUVEC) tube formation. The interaction between CIP2A and AKT1 was identified by co-immunoprecipitation (co-IP). In addition, AKT1 was overexpressed in CIP2A-silenced CAL-27 cells to perform rescue experiments to analyze the malignant biological functions of CAL-27 cells. Finally, the expression of proteins in the glycogen synthase kinase (GSK)-3β/β-catenin pathway was determined by western blot analysis. Markedly elevated CIP2A and AKT1 expression was observed in OSCC cells. CIP2A knockdown inhibited the viability, proliferation, migration and invasion, and promoted the apoptosis of CAL-27 cells. Concurrently, CIP2A loss-of-function attenuated tube formation. Results of Co-IP confirmed there was an interaction between CIP2A and AKT1. Rescue experiments suggested that AKT1 overexpression alleviated the inhibitory effects of CIP2A knockdown on the viability, proliferation, migration and invasion of CAL-27 cells, as well as tube formation in HUVECs . Additionally, CIP2A silencing significantly downregulated phosphorylated-GSK-3β and β-catenin expression, which was reversed by AKT1 overexpression. In conclusion, CIP2A could interact with AKT1 to promote the malignant biological behaviors of OSCC cells by upregulating the GSK-3β/β-catenin pathway. These findings may provide a targeted therapy for OSCC treatment.

Single-cell and bulk RNA-sequencing analysis to predict the role and clinical value of CD36 in lung squamous cell carcinoma

The majority of patients with lung squamous cell carcinoma are diagnosed at an advanced stage, which poses a challenge to the efficacy of chemotherapy. Therefore, the search for an early biomarker needs to be addressed. CD36 is a scavenger receptor expressed in various cell types. It has been reported that it is closely related to the occurrence and development of many kinds of tumours. However, its role in lung squamous cell carcinoma has not been reported. Our research aims to reveal the role of CD36 in lung squamous cell carcinoma by integrating single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing data. We used bioinformatics methods to explore the potential carcinogenicity of CD36 by analysing the data from the cancer genome map (TCGA), gene expression comprehensive map (GEO), human protein map (HPA) comparative toxicology genomics database (CTD) and other resources. Our study dissected the relationship between CD36 and prognosis and gene correlation, functional analysis, mutation of different tumours, infiltration of immune cells and exploring the interaction between CD36 and chemicals. The results showed that the expression of CD36 was heterogeneous. Compared with normal patients, the expression was low in lung squamous cell carcinoma. In addition, CD36 showed early diagnostic value in four kinds of tumours (LUSC, BLCA, BRCA and KIRC) and was positively or negatively correlated with the prognosis of different tumours. The relationship between CD36 and the tumour immune microenvironment was revealed by immunoinfiltration analysis, and many drugs that might target CD36 were identified by the comparative toxicological genomics database (CTD). In summary, through pancancer analysis, we found and verified for the first time that CD36 may play a role in the detection of lung squamous cell carcinoma. In addition, it has high specificity and sensitivity in detecting cancer. Therefore, CD36 can be used as an auxiliary index for early tumour diagnosis and a prognostic marker for lung squamous cell carcinoma.

Lipid metabolism reprogramming in head and neck cancer

Lipid metabolism reprogramming is one of the most prominent metabolic anomalies in cancer, wherein cancer cells undergo dysregulation of lipid metabolism to acquire adequate energy, cell membrane building blocks, as well as signaling molecules essential for cell proliferation, survival, invasion, and metastasis. These adaptations enable cancer cells to effectively respond to challenges posed by the tumor microenvironment, leading to cancer therapy resistance and poor cancer prognosis. Head and neck cancer, ranking as the seventh most prevalent cancer, exhibits numerous abnormalities in lipid metabolism. Nevertheless, the precise role of lipid metabolic rewiring in head and neck cancer remains unclear. In line with the LIPID MAPS Lipid Classification System and cancer risk factors, the present review delves into the dysregulated molecules and pathways participating in the process of lipid uptake, biosynthesis, transportation, and catabolism. We also present an overview of the latest advancements in understanding alterations in lipid metabolism and how they intersect with the carcinogenesis, development, treatment, and prognosis of head and neck cancer. By shedding light on the significance of metabolic therapy, we aspire to improve the overall prognosis and treatment outcomes of head and neck cancer patients.

The activated CD36-Src axis promotes lung adenocarcinoma cell proliferation and actin remodeling-involved metastasis in high-fat environment

Obesity/overweight and lipid metabolism disorders have become increased risk factors for lung cancer. Fatty acid translocase CD36 promotes cellular uptake of fatty acids. Whether and how CD36 facilitates lung adenocarcinoma (LUAD) growth in high-fat environment is unknown. Here, we demonstrated that palmitic acid (PA) or high-fat diet (HFD) promoted LUAD cell proliferation and metastasis in a CD36-dependent manner. Mechanistically, CD36 translocated from cytoplasm to cell membrane and interacted with Src kinase upon PA stimulation in human LUAD cells. Akt and ERK, downstream of Src, were then activated to mediate LUAD cell proliferation and metastasis. Furthermore, PA treatment promoted CD36 sarcolemmal translocation, where it activated Rac1 and upregulated MMP-9 through Src-Akt/ERK pathway, resulting in redistribution of cortactin, N-WASP and Arp2/3, and finally led to occurrence of finger-like protrusions of actin on cell surface to enhance cell metastasis. Compared with normal-chew diet (NCD) mice, the HFD group exhibited higher level of blood free fatty acid (FFA) and cholesterol (TC), developed larger xenograft LUAD tumors and enhanced tumor cell metastatic potential, which were accompanied by obvious sarcolemmal actin remodeling and were blocked by simultaneous CD36 knockdown in LUAD cells. Consistently, xenografted and tail vein-injected scramble-RNA-A549 cells but not CD36-shRNA-A549 in HFD mice formed metastatic LUAD tumors on the lung. CD36 inhibitor SSO significantly inhibited LUAD cell metastasis to the lung. Collectively, CD36 initiates Src signaling to promote LUAD cell proliferation and actin remodeling-involved metastasis under high-fat environment. Our study provides the new insights that CD36 is a valid target for LUAD therapy.

CD36-BATF2\MYB Axis Predicts Anti-PD-1 Immunotherapy Response in Gastric Cancer

Despite the utilization of anti-PD-1 therapy in gastric cancer (GC), the absence of a reliable predictive biomarker continues to pose a challenge. In this study, we utilized bioinformatic analysis and immunohistochemistry to develop a prediction model for activated CD4+ memory T cells, considering both mRNA and protein levels. An elevation of activated CD4+ memory T cells in GC was noted, which exhibited a strong association with the patients' overall survival. By utilizing WGCNA and DEG analysis, we discovered that BATF2, MYB, and CD36 are genes that exhibit differential expression and are linked to activated CD4+ memory T cells. Afterwards, a forecast model was built utilizing Stepwise regression and immunohistochemistry relying on the three genes. The model's high-risk score showed significant associations with a suppressive immune microenvironment. Moreover, our model exhibited encouraging prognostic value and superior performance in predicting response to immune checkpoint blockade therapy compared with the conventional CD8+PD-L1 model. In terms of mechanism, CD36 could function as a receptor upstream that identifies Helicobacter pylori and fatty acids. This recognition then results in the reduction of the BATF2-MYB protein complex and subsequent alterations in the transcription of genes associated with classical T cell activation. As a result, the activation state of CD4+ memory T cells is ultimately suppressed. The CD36-BATF2/MYB signature serves as a robust predictor of anti-PD-1 immunotherapy response in GC.

Enhancing prognostic accuracy in head and neck squamous cell carcinoma chemotherapy via a lipid metabolism-related clustered polygenic model

OBJECTIVE

Systemic chemotherapy is the first-line therapeutic option for head and neck squamous cell carcinoma (HNSCC), but it often fails. This study aimed to develop an effective prognostic model for evaluating the therapeutic effects of systemic chemotherapy.

METHODS

This study utilized CRISPR/cas9 whole gene loss-of-function library screening and data from The Cancer Genome Atlas (TCGA) HNSCC patients who have undergone systemic therapy to examine differentially expressed genes (DEGs). A lipid metabolism-related clustered polygenic model called the lipid metabolism related score (LMRS) model was established based on the identified functionally enriched DEGs. The prediction efficiency of the model for survival outcome, chemotherapy, and immunotherapy response was evaluated using HNSCC datasets, the GEO database and clinical samples.

RESULTS

Screening results from the study demonstrated that genes those were differentially expressed were highly associated with lipid metabolism-related pathways, and patients receiving systemic therapy had significantly different prognoses based on lipid metabolism gene characteristics. The LMRS model, consisting of eight lipid metabolism-related genes, outperformed each lipid metabolism gene-based model in predicting outcome and drug response. Further validation of the LMRS model in HNSCCs confirmed its prognostic value.

CONCLUSION

In conclusion, the LMRS polygenic prognostic model is helpful to assess outcome and drug response for HNSCCs and could assist in the timely selection of the appropriate treatment for HNSCC patients. This study provides important insights for improving systemic chemotherapy and enhancing patient outcomes.

Palmitic acid combined with γ-interferon inhibits gastric cancer progression by modulating tumor-associated macrophages' polarization via the TLR4 pathway

BACKGROUND

Tumor-associated macrophages (TAMs) constitute the main infiltrating immune cells in the solid tumor microenvironment. Amounting studies have analyzed the antitumor effect on immune response induced by Toll-like receptor (TLR) agonists, such as lipopolysaccharide (LPS), γ-interferon (γ-IFN), and palmitic Acid (PA). However, their combined treatment for gastric cancer (GC) has not been illuminated.

METHODS

We investigated the relevance of macrophage polarization and the effect of PA and γ-IFN in GC in vitro and in vivo. M1 and M2 macrophage-associated markers were measured by real-time quantitative PCR and flow cytometry, and the activation level of the TLR4 signaling pathways was evaluated by western blot analysis. The effect of PA and γ-IFN on the proliferation, migration, and invasion of GC cells (GCCs) was evaluated by Cell-Counting Kit-8, transwell assays, and wound-healing assays. In vivo animal models were used to verify the effect of PA and γ-IFN on tumor progression, and the M1 and M2 macrophage markers, CD8 + T lymphocytes, regulatory T cells (Treg) cells, and the myeloid-derived suppressor cells (MDSCs) in tumor tissues were analyzed by flow cytometry and immunohistochemical (IHC).

RESULTS

The results showed that this combination strategy enhanced M1-like macrophages and diminished M2-like macrophages through the TLR4 signaling pathway in vitro. In addition, the combination strategy impairs the proliferative and migratory activity of GCC in vitro and in vivo. While, the antitumor effect was abolished using the TAK-424 (a specific TLR-4 signaling pathway inhibitor) in vitro.

CONCLUSIONS

The combined treatment of PA and γ-IFN inhibited GC progression by modulating macrophages polarization via the TLR4 pathway.

Lipid metabolism reprogramming of CD8+ T cell and therapeutic implications in cancer

Effector, memory and exhaustion are three phenotypes of CD8⁺ T cell. In tumor microenvironment (TME), metabolism dysfunction of the three should take the blame for immune escape. Against background of CD8⁺ T cell in normal development, multiple determinants in TME, including nutrition competition, PD-1 signals and other cancer- CD8⁺ T cell interaction, cause metabolism reprograming, including failure in energy metabolism and other abnormal lipid metabolism. Further, incompatibility of different CD8⁺ T cell metabolism pattern results in unresponsiveness of immune checkpoint blockade (ICB). Therefore, combination of ICB and drugs aiming at abnormal lipid metabolism provides promising direction to improve cancer therapy.

The Role of CD36 in Cancer Progression and Its Value as a Therapeutic Target

Cluster of differentiation 36 (CD36) is a cell surface scavenger receptor that plays critical roles in many different types of cancer, notably breast, brain, and ovarian cancers. While it is arguably most well-known for its fatty acid uptake functions, it is also involved in regulating cellular adhesion, immune response, and apoptosis depending on the cellular and environmental contexts. Here, we discuss the multifaceted role of CD36 in cancer biology, such as its role in mediating metastasis, drug resistance, and immune evasion to showcase its potential as a therapeutic target. We will also review existing approaches to targeting CD36 in pre-clinical studies, as well as discuss the only CD36-targeting drug to advance to late-stage clinical trials, VT1021. Given the roles of CD36 in the etiology of metabolic disorders, such as atherosclerosis, diabetes, and non-alcoholic fatty liver disease, the clinical implications of CD36-targeted therapy are wide-reaching, even beyond cancer.

ATF4-mediated CD36 upregulation contributes to palmitate-induced lipotoxicity in hepatocytes

Hepatic lipotoxicity plays a central role in the pathogenesis of nonalcoholic fatty liver disease; however, the underlying mechanisms remain elusive. Here, using both cultured hepatocytes (AML-12 cells and primary mouse hepatocytes) and the liver-specific gene knockout mice, we investigated the mechanisms underlying palmitate-elicited upregulation of CD36, a class B scavenger receptor mediating long-chain fatty acids uptake, and its role in palmitate-induced hepatolipotoxicity. We found that palmitate upregulates hepatic CD36 expression. Despite being a well-established target gene of PPARγ transactivation, our data demonstrated that the palmitate-induced CD36 upregulation in hepatocytes is in fact PPARγ-independent. We previously reported that the activation of ATF4, one of three canonical pathways activated upon endoplasmic reticulum (ER) stress induction, contributes to palmitate-triggered lipotoxicity in hepatocytes. In this study, our data revealed for the first time that ATF4 plays a critical role in mediating hepatic CD36 expression. Genetic inhibition of ATF4 attenuated CD36 upregulation induced by either palmitate or ER stress inducer tunicamycin in hepatocytes. In mice, tunicamycin upregulates liver CD36 expression, whereas hepatocyte-specific ATF4 knockout mice manifest lower hepatic CD36 expression when compared with control animals. Furthermore, we demonstrated that CD36 upregulation upon palmitate exposure represents a feedforward mechanism in that siRNA knockdown of CD36 in hepatocytes blunted ATF4 activation induced by both palmitate and tunicamycin. Finally, we confirmed that the ATF4-CD36 pathway activation contributes to palmitate-induced hepatolipotoxicity as genetic inhibition of either ATF4 or CD36 alleviated cell death and intracellular triacylglycerol accumulation. Collectively, our data demonstrate that CD36 upregulation by ATF4 activation contributes to palmitate-induced hepatic lipotoxicity.NEW & NOTEWORTHY We provided the initial evidence that ATF4 is a principal transcription factor mediating hepatic CD36 expression in that both palmitate- and ER stress-elicited CD36 upregulation was blunted by ATF4 gene knockdown in hepatocytes, and hepatocyte-specific ATF4 knockout mice manifested lower hepatic CD36 expression. We further confirmed that the ATF4-CD36 pathway activation contributes to palmitate-induced hepatolipotoxicity as genetic inhibition of either ATF4 or CD36 alleviated cell death and intracellular triacylglycerol accumulation in response to exogenous palmitate exposure.

Genome-Scale CRISPR screen identifies LAPTM5 driving lenvatinib resistance in hepatocellular carcinoma

ABBREVIATIONS

cld-CASP3: cleaved caspase 3; cld-PARP: cleaved PARP; DTP: drug tolerant persister; GO: Gene Ontology; GTEx: The Genotype-Tissue Expression; HCC: hepatocellular carcinoma; HCQ: hydroxychloroquine; IC50: half maximal inhibitory concentration value; KEGG: Kyoto Encyclopedia of Genes and Genomes; LAPTM5: lysosomal protein transmembrane 5; NT: non-targeting; PDC: patient-derived primary cell lines; PDO: patient-derived primary organoid; TCGA: The Cancer Genome Atlas.

Long non-coding RNA SNHG11 regulates the Wnt/β-catenin signaling pathway through rho/ROCK in trabecular meshwork cells

Trabecular meshwork (TM) cell dysfunction is the leading cause of elevated intraocular pressure (IOP) and glaucoma. The long non-coding RNA (lncRNA) small nucleolar RNA host gene 11 (SNHG11) is associated with cell proliferation and apoptosis, but its biological functions and role in glaucoma pathogenesis remain unclear. In the present study, we investigated the role of SNHG11 in TM cells using immortalized human TM and glaucomatous human TM (GTM₃ ) cells and an acute ocular hypertension mouse model. SNHG11 expression was depleted using siRNA targeting SNHG11. Transwell assays, quantitative real-time PCR analysis (qRT-PCR), western blotting, and CCK-8 assay were used to evaluate cell migration, apoptosis, autophagy, and proliferation. Wnt/β-catenin pathway activity was inferred from qRT-PCR, western blotting, immunofluorescence, and luciferase reporter and TOPFlash reporter assays. The expression of Rho kinases (ROCKs) was detected using qRT-PCR and western blotting. SNHG11 was downregulated in GTM₃ cells and mice with acute ocular hypertension. In TM cells, SNHG11 knockdown inhibited cell proliferation and migration, activated autophagy, and apoptosis, repressing the Wnt/β-catenin signaling pathway, and activated Rho/ROCK. Wnt/β-catenin signaling pathway activity increased in TM cells treated with ROCK inhibitor. SNHG11 regulated Wnt/β-catenin signaling through Rho/ROCK by increasing GSK-3β expression and β-catenin phosphorylation at Ser33/37/Thr41 while decreasing β-catenin phosphorylation at Ser675. We demonstrate that the lncRNA SNHG11 regulates Wnt/β-catenin signaling through Rho/ROCK via β-catenin phosphorylation at Ser675 or GSK-3β-mediated phosphorylation at Ser33/37/Thr41, affecting cell proliferation, migration, apoptosis, and autophagy. Through its effects on Wnt/β-catenin signaling, SNHG11 is implicated in glaucoma pathogenesis and is a potential therapeutic target.

Palmitate paves the way to lung metastasis

New findings by Altea-Manzano et al. demonstrate that primary breast tumours or a high-fat diet induce palmitate secretion by alveolar type 2 (AT2) cells to prepare a premetastatic niche that promotes lung metastasis. Palmitate is utilised by cancer cells via carnitine palmitoyltransferase 1a (CPT1a) and lysine acetyltransferase 2a (KAT2a) to acetylate nuclear factor-κB (NF-κB)/p65. Blocking these enzymes reduced metastasis formation in both lean and high-fat diet mice.

Reprogramming of palmitic acid induced by dephosphorylation of ACOX1 promotes β-catenin palmitoylation to drive colorectal cancer progression

Metabolic reprogramming is a hallmark of cancer. However, it is not well known how metabolism affects cancer progression. We identified that metabolic enzyme acyl-CoA oxidase 1 (ACOX1) suppresses colorectal cancer (CRC) progression by regulating palmitic acid (PA) reprogramming. ACOX1 is highly downregulated in CRC, which predicts poor clinical outcome in CRC patients. Functionally, ACOX1 depletion promotes CRC cell proliferation in vitro and colorectal tumorigenesis in mouse models, whereas ACOX1 overexpression inhibits patient-derived xenograft growth. Mechanistically, DUSP14 dephosphorylates ACOX1 at serine 26, promoting its polyubiquitination and proteasomal degradation, thereby leading to an increase of the ACOX1 substrate PA. Accumulated PA promotes β-catenin cysteine 466 palmitoylation, which inhibits CK1- and GSK3-directed phosphorylation of β-catenin and subsequent β-Trcp-mediated proteasomal degradation. In return, stabilized β-catenin directly represses ACOX1 transcription and indirectly activates DUSP14 transcription by upregulating c-Myc, a typical target of β-catenin. Finally, we confirmed that the DUSP14-ACOX1-PA-β-catenin axis is dysregulated in clinical CRC samples. Together, these results identify ACOX1 as a tumor suppressor, the downregulation of which increases PA-mediated β-catenin palmitoylation and stabilization and hyperactivates β-catenin signaling thus promoting CRC progression. Particularly, targeting β-catenin palmitoylation by 2-bromopalmitate (2-BP) can efficiently inhibit β-catenin-dependent tumor growth in vivo, and pharmacological inhibition of DUSP14-ACOX1-β-catenin axis by Nu-7441 reduced the viability of CRC cells. Our results reveal an unexpected role of PA reprogramming induced by dephosphorylation of ACOX1 in activating β-catenin signaling and promoting cancer progression, and propose the inhibition of the dephosphorylation of ACOX1 by DUSP14 or β-catenin palmitoylation as a viable option for CRC treatment.

STAT proteins in cancer: orchestration of metabolism

Reprogrammed metabolism is a hallmark of cancer. However, the metabolic dependency of cancer, from tumour initiation through disease progression and therapy resistance, requires a spectrum of distinct reprogrammed cellular metabolic pathways. These pathways include aerobic glycolysis, oxidative phosphorylation, reactive oxygen species generation, de novo lipid synthesis, fatty acid β-oxidation, amino acid (notably glutamine) metabolism and mitochondrial metabolism. This Review highlights the central roles of signal transducer and activator of transcription (STAT) proteins, notably STAT3, STAT5, STAT6 and STAT1, in orchestrating the highly dynamic metabolism not only of cancer cells but also of immune cells and adipocytes in the tumour microenvironment. STAT proteins are able to shape distinct metabolic processes that regulate tumour progression and therapy resistance by transducing signals from metabolites, cytokines, growth factors and their receptors; defining genetic programmes that regulate a wide range of molecules involved in orchestration of metabolism in cancer and immune cells; and regulating mitochondrial activity at multiple levels, including energy metabolism and lipid-mediated mitochondrial integrity. Given the central role of STAT proteins in regulation of metabolic states, they are potential therapeutic targets for altering metabolic reprogramming in cancer.

An immune-related prognostic signature associated with immune landscape and therapeutic responses in gastric cancer

Immune-related genes (IRGs) have attracted attention in recent years as therapeutic targets in various tumors. However, the role of IRGs in gastric cancer (GC) has not been clearly elucidated. This study presents a comprehensive analysis exploring the clinical, molecular, immune, and drug response features characterizing the IRGs in GC. Data were acquired from the TCGA and GEO databases. The Cox regression analyses were performed to develop a prognostic risk signature. The genetic variants, immune infiltration, and drug responses associated with the risk signature were explored using bioinformatics methods. Lastly, the expression of the IRS was verified by qRT-PCR in cell lines. In this manner, an immune-related signature (IRS) was established based on 8 IRGs. According to the IRS, patients were divided into the low-risk group (LRG) and high-risk group (HRG). Compared with the HRG, the LRG was characterized by a better prognosis, high genomic instability, more CD8+ T cell infiltration, greater sensitivity to chemotherapeutic drugs, and greater likelihood of benefiting from the immunotherapy. Moreover, the expression result showed good consistency between the qRT-PCR and TCGA cohort. Our findings provide insights into the specific clinical and immune features underlying the IRS, which may be important for patient treatment.

miR-199a-3p promotes gastric cancer progression by promoting its stemness potential via DDR2 mediation

BACKGROUND

Peritoneal metastasis (PM) is an independent prognostic factor in gastric cancer (GC), however, the underlying mechanisms of PM occurrence remain unclear.

METHOD

The roles of DDR2 were investigated in GC and its potential relationship to PM, and orthotopic implants into nude mice were performed to assess the biological effects of DDR2 on PM.

RESULTS

Herein, DDR2 level is more significantly observed to elevate in PM lesion than the primary lesion. GC with DDR2-high expression evokes a worse overall survival (OS) in TCGA, similar results of the gloomy OS with high DDR2 levels are clarified via the stratifying stage of TNM. The conspicuously increased expression of DDR2 was found in GC cell lines, luciferase reporter assays verified that miR-199a-3p directly targeted DDR2 gene, which was correlated to tumor progression. We ulteriorly observed DDR2 participated in GC stemness maintenance via mediating pluripotency factor SOX2 expression and implicated in autophagy and DNA damage of cancer stem cells (CSCs). In particular, DDR2 dominated EMT programming through recruiting NFATc1-SOX2 complex to Snai1 in governing cell progression, controlling by DDR2-mTOR-SOX2 axis in SGC-7901 CSCs. Furthermore, DDR2 promoted the tumor peritoneal dissemination in gastric xenograft mouse model.

CONCLUSION

Phenotype screens and disseminated verifications incriminating in GC exposit the miR-199a-3p-DDR2-mTOR-SOX2 axis as a clinically actionable target for tumor PM progression. The herein-reported DDR2-based underlying axis in GC represents novel and potent tools for studying the mechanisms of PM.

3,3'-Diindolylmethane Augments 5-Fluorouracil-InducedGrowth Suppression in Gastric Cancer Cells through Suppression of the Akt/GSK-3β and WNT/Beta-Catenin

Gastric cancer (GC) is one of the most lethal cancers in South Korea, and it is a cancer of concern worldwide. 5-fluorouracil (5-Fu) is commonly used as the first-line therapy for advanced GC; however, its side effects often limit the dosage range and impair patients' quality of life. Due to the limitations of current chemotherapy, new anticancer therapies are urgently needed. 3,3'-diindolylmethane (DIM) has been reported to have the ability to protect against various types of cancer. Our study aimed to elucidate the anticancer effect of DIM in GC when treated with the chemotherapeutic agent 5-Fu. In our results, combined treatment with DIM and 5-Fu resulted in higher apoptosis and lower cell proliferation than treatment with 5-Fu in SNU484 and SNU638 cell lines. Furthermore, when DIM and 5-Fu were administered together, cell invasion was diminished by mediated E-cadherin, MMP-9, and uPA; p-Akt and p-GSK-3β levels were reduced more significantly than when 5-Fu was administered alone. Moreover, in the Wnt signaling pathway, combined treatment of DIM and 5-Fu diminished β-catenin levels in the nucleus and inhibited cyclin D1and c-Myc protein levels. The Akt inhibitor, wortmannin, further inhibited the levels of β-catenin and c-Myc that were inhibited by DIM and 5-Fu. Furthermore, an animal xenograft model demonstrated that DIM combined with 5-Fu considerably reduced tumor growth without any toxic effects by regulating the Akt/GSK-3β and β-catenin levels. Our findings suggest that DIM significantly potentiates the anticancer effects of 5-Fu by targeting the Akt/GSK-3β and WNT/β-catenin because the combination therapy is more effective than 5-Fu alone, thereby offering an innovative potential therapy for patients with GC.

Effective breast cancer therapy based on palmitic acid-loaded PLGA nanoparticles

Although new strategies for breast cancer treatment have yielded promising results, most drugs can lead to serious side effects when applied systemically. Doxorubicin (DOX), currently the most effective chemotherapeutic drug to treat breast cancer, is poorly selective towards tumor cells and treatment often leads to the development of drug resistance. Recent studies have indicated that several fatty acids (FAs) have beneficial effects on inhibiting tumorigenesis. The saturated FA palmitic acid (PA) showed anti-tumor activities in several types of cancer, as well as effective repolarization of M2 macrophages towards the anti-tumorigenic M1 phenotype. However, water insolubility and cellular impermeability limit the use of PA in vivo. To overcome these limitations, here, we encapsulated PA into a poly(d,l-lactic co-glycolic acid) (PLGA) nanoparticle (NP) platform, alone and in combination with DOX, to explore PA's potential as mono or combinational breast cancer therapy. Our results showed that PLGA-PA-DOX NPs and PLGA-PA NPs significantly reduced the viability and migratory capacity of breast cancer cells in vitro. In vivo studies in mice bearing mammary tumors demonstrated that PLGA-PA-NPs were as effective in reducing primary tumor growth and metastasis as NPs loaded with DOX, PA and DOX, or free DOX. At the molecular level, PLGA-PA NPs reduced the expression of genes associated with multi-drug resistance and inhibition of apoptosis, and induced apoptosis via a caspase-3-independent pathway in breast cancer cells. In addition, immunohistochemical analysis of residual tumors showed a reduction in M2 macrophage content and infiltration of leukocytes after treatment of PLGA-PA NPs and PLGA-PA-DOX NPs, suggesting immunomodulatory properties of PA in the tumor microenvironment. In conclusion, the use of PA alone or in combination with DOX may represent a promising novel strategy for the treatment of breast cancer.

Development of anoikis-related genes signature to predict the prognosis in gastric cancer patients

Background

It is well known that the prognosis of Gastric cancer (GC) patient is affected by many factors. However, the latent impact of anoikis on the prognosis of GC patients is insufficient understood.

Methods

According to the Cancer Genome Atlas (TCGA) database, we elected discrepantly expressed anoikis-related genes (ARGs). Univariate cox and the least absolute shrinkage and selection operator (lasso) analysis were applied to build the ARGs signature. The prognostic effect of the ARGs signature was also evaluated. A series of algorithms were performed to evaluate the discrepancies in the immune microenvironment. Moreover, the correlation between drug sensitivity and ARGs signature was analyzed. We also performed Real-Time Polymerase Chain Reaction (RT-PCR) to probe the signature.

Results

The ARGs signature of 9 genes was constructed, which was apparently interrelated with the prognosis. The nomogram was established by combining the ARGs signature with clinicopathological characteristics. We found that the predictive power was noteworthily superior to other individual predictors. The immune microenvironment analysis indicated that ESTIMATEscore, ImmuneScores, StromalScores, tumor immune dysfunction and exclusion (TIDE) score were lower in the low-risk group, while immunophenoscore (IPS) was on the contrary. The infiltrated immune cells and immune checkpoint (ICP) expression levels were significantly different between the two groups. Furthermore, nine drugs were positively associated with the ARGs signature score. The results of RT-PCR analysis were consistent with our previous differential expression analysis.

Conclusion

The developed ARGs signature could act as the biomarker and provide a momentous reference for Individual therapy of GC patients.

Macrophage scavenger receptors: Tumor support and tumor inhibition

Tumor-associated macrophages (TAMs) are a heterogeneous population of myeloid cells that constitute up to 50% of the cell mass of human tumors. TAMs interact with the components of the tumor microenvironment (TME) by using scavenger receptors (SRs), a large superfamily of multifunctional receptors that recognize, internalize and transport to the endosomal/lysosomal pathway apoptotic cells, cytokines, matrix molecules, lipid modified lipoproteins and other unwanted-self ligands. In our review, we summarized state-of-the art for the role of macrophage scavenger receptors in tumor development and their significance as cancer biomarkers. In this review we focused on functional activity of TAM-expressing SRs in animal models and in patients, and summarized the data for different human cancer types about the prognostic significance of TAM-expressed SRs. We discussed the role of SRs in the regulation of cancer cell biology, cell-cell and cell-matrix interaction in TME, immune status in TME, angiogenesis, and intratumoral metabolism. Targeting of tumor-promoting SRs can be a promising therapeutic approach in anti-cancer therapy. In our review we provide evidence for both tumor supporting and tumor inhibiting functions of scavenger receptors expressed on TAMs. We focused on the key differences in the prognostic and functional roles of SRs that are specific for cancer types. We highlighted perspectives for inhibition of tumor-promoting SRs in anti-cancer therapy.

Fatty acid metabolism reprogramming in ccRCC: mechanisms and potential targets

Lipid droplet formation is a defining histological feature in clear-cell renal cell carcinoma (ccRCC) but the underlying mechanisms and importance of this biological behaviour have remained enigmatic. De novo fatty acid (FA) synthesis, uptake and suppression of FA oxidation have all been shown to contribute to lipid storage, which is a necessary tumour adaptation rather than a bystander effect. Clinical studies and mechanistic investigations into the roles of different enzymes in FA metabolism pathways have revealed new metabolic vulnerabilities that hold promise for clinical effect. Several metabolic alterations are associated with worse clinical outcomes in patients with ccRCC, as lipogenic genes drive tumorigenesis. Enzymes involved in the intrinsic FA metabolism pathway include FA synthase, acetyl-CoA carboxylase, ATP citrate lyase, stearoyl-CoA desaturase 1, cluster of differentiation 36, carnitine palmitoyltransferase 1A and the perilipin family, and each might be potential therapeutic targets in ccRCC owing to the link between lipid deposition and ccRCC risk. Adipokines and lipid species are potential biomarkers for diagnosis and treatment monitoring in patients with ccRCC. FA metabolism could potentially be targeted for therapeutic intervention in ccRCC as small-molecule inhibitors targeting the pathway have shown promising results in preclinical models.

Lipid metabolism marker CD36 is associated with 18FDG-PET/CT false negative lymph nodes in head and neck squamous cell carcinoma

Background

Lymph node metastasis frequently occurs in head and neck squamous cell carcinoma (HNSCC) patients, and [¹⁸F] fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸FDG-PET/CT) examination for lymph node metastasis could result in false negativity and delay following treatment. However, the mechanism and resolution for ¹⁸FDG-PET/CT false negatives remain unclear. Our study was aim to found biomarkers for false negativity and true positivity from a metabolic perspective.

Methods

Ninety-two patients diagnosed with HNSCC who underwent preoperative ¹⁸FDG-PET/CT and subsequent surgery in our institution were reviewed. Immunohistochemistry (IHC) examinations of glucose metabolism (GLUT1 and GLUT5), amino acid metabolism4 (GLS and SLC1A5), and lipid metabolism (CPT1A and CD36) markers were conducted on their primary lesion and lymph node sections.

Results

We identified specific metabolic patterns of the false-negative group. Significantly, CD36 IHC score of primary lesions was higher in false-negative group than true-positive group. Moreover, we validated pro-invasive biological effects of CD36 by bioinformatics analysis as well as experiments. Conclusion: IHC examination of CD36 expression, which is a lipid metabolism marker, in primary lesions could distinguish HNSCC patients' lymph nodes false negatives in ¹⁸FDG-PET/CT.

Tissue-resident memory T cells in gastrointestinal tumors: turning immune desert into immune oasis

Tissue-resident memory T cells (Trm) are a particular type of T cell subgroup, which stably reside in tissues and have been revealed to be the most abundant memory T cell population in various tissues. They can be activated in the local microenvironment by infection or tumor cells and rapidly clean them up to restore homeostasis of local immunity in gastrointestinal tissues. Emerging evidence has shown that tissue-resident memory T cells have great potential to be mucosal guardians against gastrointestinal tumors. Therefore, they are considered potential immune markers for immunotherapy of gastrointestinal tumors and potential extraction objects for cell therapy with essential prospects in clinical translational therapy. This paper systematically reviews the role of tissue-resident memory T cells in gastrointestinal tumors and looks to the future of their prospect in immunotherapy to provide a reference for clinical application.