Accumulated cholesterol protects tumours from elevated lipid peroxidation in the microenvironment

Cholesterol metabolism: A strategy for overcoming drug resistance in tumors

Despite significant advancements in targeted tumor therapies, the emergence of drug resistance remains a complex challenge. Cholesterol accumulation within tumor cells plays a crucial role in mediating drug resistance through various mechanisms, including altered membrane dynamics, enhanced drug efflux, and activation of survival signaling pathways. Targeting cholesterol metabolism presents an innovative strategy to enhance therapeutic sensitivity, particularly in breast cancer. Consequently, ongoing preclinical studies and clinical trials involving cholesterol-lowering agents indicate a promising direction for improving treatment outcomes in tumors. The combination of these agents with existing therapeutic regimens may lead to enhanced efficacy, highlighting the necessity for continued research in this vital area. This review examines the impact of cholesterol metabolism on drug resistance in tumors, particularly solid tumors, identifies therapeutic targets in this metabolic pathway (with a special focus on breast cancer), and discusses recent advances in cholesterol-lowering drugs in preclinical, as well as those that have entered clinical trials.

Fangchinoline suppresses nasopharyngeal carcinoma progression by inhibiting SQLE to regulate the PI3K/AKT pathway dysregulation

BACKGROUND AND PURPOSE

Squalene epoxidase (SQLE), a key enzyme in cholesterol metabolism, remains underexplored in nasopharyngeal carcinoma (NPC). Additionally, the therapeutic potential of Fangchinoline, an alkaloid with anticancer properties, has yet to be systematically evaluated. This research investigates Fangchinoline's efficacy in NPC treatment and SQLE-related mechanisms.

METHODS

Drug screening in NPC cell lines C666-1 and 5-8F identified potential candidates. IC50 values were determined using CCK-8 assays, and apoptosis, proliferation, and invasion were assessed via Annexin V/PI staining, EdU staining, and Transwell assays. Cholesterol levels were quantified using a TG kit. RNA sequencing with GO/KEGG analyses identified key pathways. Correlation analysis was performed via cBioPortal and GEPIA2 databases, protein interaction networks via STRING and Cytoscape, and survival analysis via Kaplan-Meier curves. Gene and protein expression were validated with qPCR and Western blot, and an NPC mouse model confirmed in vivo efficacy.

RESULTS

Fangchinoline inhibited NPC cell proliferation, induced apoptosis, and reduced cholesterol accumulation. RNA sequencing revealed that Fangchinoline downregulated SQLE expression, suppressing the PI3K/AKT pathway. Correlation and protein interaction analyses highlighted SQLE's role in NPC progression, and survival analysis confirmed its clinical relevance. By targeting SQLE and disrupting cholesterol metabolism, Fangchinoline suppressed tumor growth both in vitro and in vivo.

CONCLUSION

Our study demonstrates that Fangchinoline inhibits NPC growth by targeting SQLE and disrupting the PI3K/AKT pathway, providing new insights into SQLE as a therapeutic target in NPC.

The role of fatty acid metabolism on B cells and B cell-related autoimmune diseases

Fatty acid metabolism plays a critical role in regulating immune cell function, including B cells, which are central to humoral immunity and the pathogenesis of autoimmune diseases. Emerging evidence suggests that fatty acid metabolism influences B cell development, activation, differentiation, and antibody production, thereby impacting B cell-related autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS). In this review, we discuss the mechanisms by which fatty acid metabolism modulates B cell biology, including energy provision, membrane composition, and signaling pathways. We highlight how alterations in fatty acid synthesis, oxidation, and uptake affect B cell function and contribute to autoimmune pathogenesis. Additionally, we explore the therapeutic potential of targeting fatty acid metabolism in B cells to treat autoimmune diseases. Understanding the interplay between fatty acid metabolism and B cell immunity may provide novel insights into the development of precision therapies for B cell-mediated autoimmune disorders.

Lipid rafts: novel therapeutic targets for metabolic, neurodegenerative, oncological, and cardiovascular diseases

Lipid rafts are specialized microdomains within cellular membranes enriched with cholesterol and sphingolipids that play key roles in cellular organization, signaling, and homeostasis. This review highlights their involvement in protein clustering, energy metabolism, oxidative stress responses, inflammation, autophagy, and apoptosis. These findings clarify their influence on signaling, trafficking, and adhesion while interacting with the extracellular matrix, cytoskeleton, and ion channels, making them pivotal in the progression of various diseases. This review further addresses their contributions to immune responses, including autoimmune diseases, chronic inflammation, and cytokine storms. Additionally, their role as entry points for pathogens has been demonstrated, with raft-associated receptors being exploited by viruses and bacteria to increase infectivity and evade immune defenses. Disruptions in lipid raft dynamics are linked to oxidative stress and cellular signaling defects, which contribute to metabolic, neurodegenerative, and cardiovascular diseases. This review underscores their potential as therapeutic targets, discussing innovations such as engineered lipid raft transplantation. Advances in analytical techniques such as mass spectrometry have expanded our understanding of lipid raft composition and dynamics, opening new directions for research. By consolidating the current insights, we highlight the therapeutic potential of lipid rafts and highlight the need for further exploration of their molecular mechanisms.

Cholesterol effects on the tumor immune microenvironment: from fundamental concepts to mechanisms and implications

In many cancers, the tumor microenvironment is enriched with cholesterol due to increased biosynthesis and uptake by cancer cells, resulting in the accumulation of cholesterol, cholesterol esters, oxysterols and other metabolites with various functions. These molecules serve as structural components, energy sources and intracellular signaling mediators, while their toxic by-products are secreted to suppress anti-tumor immune activity and prevent lipid peroxidation that could induce cancer cell apoptosis. Immune cells in the tumor microenvironment also contribute to cholesterol dynamics. Tumor-associated macrophages (TAMs) release cholesterol to support tumor cell metabolism, while myeloid-derived suppressor cells (MDSCs) also release cholesterol and consume essential metabolites such as L-arginine, which impairs T-cell proliferation and activation. Elevated cholesterol in dendritic cells impairs migration and tumor antigen presentation and, in lymphocytes, favors the development of a regulatory T cells (Treg) phenotype and inhibits the release of antitumor cytokines, further weakening the immune response. These findings suggest that targeting cholesterol metabolism is a promising strategy for cancer treatment, improving the efficacy of immune checkpoint blockade (ICB) therapies. In this manuscript, the molecular mechanisms underlying the effects of cholesterol on the tumor immune landscape are reviewed and the potential of cholesterol-lowering drugs to enhance antitumor immune responses is explored.

Cholesterol metabolism in tumor immunity: Mechanisms and therapeutic opportunities for cancer

Cholesterol is an essential component of the cell membrane which plays a critical role in the survival of immune and tumor cells. Reprogramming of cholesterol metabolism in both tumor cells and immune cells can impact tumor progression and anti-tumor immune responses. Strategies aimed at modulating cholesterol metabolism have been demonstrated to be effective in hindering tumor growth and boosting anti-tumor immune functions. This review provides a thorough analysis of intracellular cholesterol homeostasis regulation in cells, focusing on key genes and signaling pathways. It particularly emphasizes the regulatory mechanisms and importance of the cholesterol presence state (esterified/free), levels of cholesterol, and its metabolites in immune and tumor cells. Additionally, the review thoroughly explores how cholesterol metabolism and sources (endogenous/exogenous) in the tumor microenvironment (TME) contribute to the interplay among tumor cells, immune suppressor cells, and immune effector cells, promoting cancer progression and immune evasion. It also delves into current insights on the influence of cholesterol metabolites and related drugs in regulating tumor development or immunotherapy. Finally, it presents an overview of recent advancements in clinical and preclinical trials investigating the efficacy of targeted cholesterol metabolism treatments and combination therapies in cancer management, while proposing potential future research directions in tumor immunity. This review is poised to offer fresh perspectives and avenues for examining the potential of cancer immunotherapy centered on cholesterol metabolism regulation.

Ferroptosis: when metabolism meets cell death

We present here a comprehensive update on recent advancements in the field of ferroptosis, with a particular emphasis on its metabolic underpinnings and physiological impacts. After briefly introducing landmark studies that have helped to shape the concept of ferroptosis as a distinct form of cell death, we critically evaluate the key metabolic determinants involved in its regulation. These include the metabolism of essential trace elements such as selenium and iron; amino acids such as cyst(e)ine, methionine, glutamine/glutamate, and tryptophan; and carbohydrates, covering glycolysis, the citric acid cycle, the electron transport chain, and the pentose phosphate pathway. We also delve into the mevalonate pathway and subsequent cholesterol biosynthesis, including intermediate metabolites like dimethylallyl pyrophosphate, squalene, coenzyme Q (CoQ), vitamin K, and 7-dehydrocholesterol, as well as fatty acid and phospholipid metabolism, including the biosynthesis and remodeling of ester and ether phospholipids and lipid peroxidation. Next, we highlight major ferroptosis surveillance systems, specifically the cyst(e)ine/glutathione/glutathione peroxidase 4 axis, the NAD(P)H/ferroptosis suppressor protein 1/CoQ/vitamin K system, and the guanosine triphosphate cyclohydrolase 1/tetrahydrobiopterin/dihydrofolate reductase axis. We also discuss other potential anti- and proferroptotic systems, including glutathione S-transferase P1, peroxiredoxin 6, dihydroorotate dehydrogenase, glycerol-3-phosphate dehydrogenase 2, vitamin K epoxide reductase complex subunit 1 like 1, nitric oxide, and acyl-CoA synthetase long-chain family member 4. Finally, we explore ferroptosis's physiological roles in aging, tumor suppression, and infection control, its pathological implications in tissue ischemia-reperfusion injury and neurodegeneration, and its potential therapeutic applications in cancer treatment. Existing drugs and compounds that may regulate ferroptosis in vivo are enumerated.

LRRK2 reduces the sensitivity to TKI and PD-1 blockade in ccRCC via activating LPCAT1

Tyrosine kinase inhibitor (TKI) and immune checkpoint inhibitor (ICI) combination therapy is emerging as a major therapeutic strategy for advanced clear cell renal cell carcinoma (ccRCC). To define the druggable targets for improvement of TKI and ICI combination therapy in ccRCC, we analyzed a commercial protein kinase inhibitor dataset and a public ccRCC dataset and identified LRRK2 as a potential candidate that can be targeted by a small molecule inhibitor. We demonstrated that LRRK2 was transcriptionally upregulated by HIF2A and enabled to drive proliferation of ccRCC cells in a manner independent of its kinase activity. LRRK2 inhibits the RBX1-mediated degradation of lipid metabolism modulator LPCAT1 to reducing the sensitivity to TKI and PD-1 blockade in ccRCC. Specifically, LRRK2/LPCAT1 upregulated IL-1β expression levels through AKT and also increased IL-1β shearing by activating inflammasome. To target the kinase-independent activity of LRRK2, we developed an LR-protac and showed that LR-protac decreased LRRK2 protein level and enhanced the antitumor effect of PD-1 blockade and TKI in ccRCC. These data indicate that LRRK2 is a viable target for improvement of the efficacy of PD-1 blockade and TKI in ccRCC.

Emerging Roles of Nanozyme in Tumor Metabolism Regulation: Mechanisms, Applications, and Future Directions

Nanozymes, nanomaterials with intrinsic enzyme activity, have garnered significant attention in recent years due to their catalytic abilities comparable to natural enzymes, cost-effectiveness, high catalytic activities, and stability against environmental fluctuations. As functional analogs of natural enzymes, nanozymes participate in various critical metabolic processes, including glucose metabolism, lactate metabolism, and the maintenance of redox homeostasis, all of which are essential for normal cellular functions. However, disruptions in these metabolic pathways frequently promote tumorigenesis and progression, making them potential therapeutic targets. While several therapies targeting tumor metabolism are currently in clinical or preclinical stages, their efficacy requires further enhancement. Consequently, nanozymes that target tumor metabolism are regarded as a promising therapeutic strategy. Despite extensive studies investigating the application of nanozymes in tumor metabolism, relevant reviews are relatively scarce. This article first introduces the physicochemical properties and biological behaviors of nanozymes. Subsequently, we analyze the role of nanozymes in tumor metabolism and explore their potential applications in tumor therapy. In conclusion, this review aims to foster innovative research in related fields and advance the development of nanozyme-based strategies for cancer diagnostics and therapeutics.

Targeting the mevalonate pathway potentiates NUAK1 inhibition-induced immunogenic cell death and antitumor immunity

The induction of immunogenic cell death (ICD) impedes tumor progression via both tumor cell-intrinsic and -extrinsic mechanisms, representing a robust therapeutic strategy. However, ICD-targeted therapy remains to be explored and optimized. Through kinome-wide CRISPR-Cas9 screen, NUAK family SNF1-like kinase 1 (NUAK1) is identified as a potential target. The ICD-provoking effect of NUAK1 inhibition depends on the production of reactive oxygen species (ROS), consequent to the downregulation of nuclear factor erythroid 2-related factor 2 (NRF2)-mediated antioxidant gene expression. Moreover, the mevalonate pathway/cholesterol biosynthesis, activated by spliced form of X-box binding protein 1 (XBP1s) downstream of ICD-induced endoplasmic reticulum (ER) stress, functions as a negative feedback mechanism. Targeting the mevalonate pathway with CRISPR knockout or the 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibitor simvastatin amplifies NUAK1 inhibition-mediated ICD and antitumor activity, while cholesterol dampens ROS and ICD, and therefore also dampens tumor suppression. The combination of NUAK1 inhibitor and statin enhances the efficacy of anti-PD-1 therapy. Collectively, our study unveils the promise of blocking the mevalonate-cholesterol pathway in conjunction with ICD-targeted immunotherapy.

The role of ferroptosis in acute kidney injury: mechanisms and potential therapeutic targets

Acute kidney injury (AKI) is one of the most common and severe clinical renal syndromes with high morbidity and mortality. Ferroptosis is a form of programmed cell death (PCD), is characterized by iron overload, reactive oxygen species accumulation, and lipid peroxidation. As ferroptosis has been increasingly studied in recent years, it is closely associated with the pathophysiological process of AKI and provides a target for the treatment of AKI. This review offers a comprehensive overview of the regulatory mechanisms of ferroptosis, summarizes its role in various AKI models, and explores its interaction with other forms of cell death, it also presents research on ferroptosis in AKI progression to other diseases. Additionally, the review highlights methods for detecting and assessing AKI through the lens of ferroptosis and describes potential inhibitors of ferroptosis for AKI treatment. Finally, the review presents a perspective on the future of clinical AKI treatment, aiming to stimulate further research on ferroptosis in AKI.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

Immunotherapy has become a crucial strategy in cancer treatment, but its effectiveness is often constrained. Most cancer immunotherapies focus on stimulating T-cell-mediated immunity by driving the cancer-immunity cycle, which includes tumor antigen release, antigen presentation, T cell activation, infiltration, and tumor cell killing. However, metabolism reprogramming in the tumor microenvironment (TME) supports the viability of cancer cells and inhibits the function of immune cells within this cycle, presenting clinical challenges. The distinct metabolic needs of tumor cells and immune cells require precise and selective metabolic interventions to maximize therapeutic outcomes while minimizing adverse effects. Recent advances in nanotherapeutics offer a promising approach to target tumor metabolism reprogramming and enhance the cancer-immunity cycle through tailored metabolic modulation. In this review, we explore cutting-edge nanomaterial strategies for modulating tumor metabolism to improve therapeutic outcomes. We review the design principles of nanoplatforms for immunometabolic modulation, key metabolic pathways and their regulation, recent advances in targeting these pathways for the cancer-immunity cycle enhancement, and future prospects for next-generation metabolic nanomodulators in cancer immunotherapy. We expect that emerging immunometabolic modulatory nanotechnology will establish a new frontier in cancer immunotherapy in the near future.

Sterols in ferroptosis: from molecular mechanisms to therapeutic strategies

Ferroptosis, a novel cell death mode driven by iron-dependent phospholipid (PL) peroxidation, has emerged as a promising therapeutic strategy for the treatments of cancer, cardiovascular diseases, and ischemic-reperfusion injury (IRI). PL peroxidation, the key process of ferroptosis, requires polyunsaturated fatty acid (PUFA)-containing PLs (PL-PUFAs) as substrates, undergoing a chain reaction with iron and oxygen. Cells prevent ferroptosis by maintaining a homeostatic equilibrium among substrates, processes, and detoxification of PL peroxidation. Sterols, lipids abundant in cell membranes, directly participate in PL peroxidation and influence ferroptosis sensitivity. Sterol metabolism also plays a key role in ferroptosis, and targeting sterols presents significant potential for treating numerous ferroptosis-associated disorders. This review elucidates the fundamental mechanisms of ferroptosis, emphasizing how sterols modulate this process and their therapeutic potential.

Investigation of the Cholesterol Biosynthesis by Heart-Cut Liquid Chromatography and Mass Spectrometric Detection

The biosynthesis and homeostasis of cholesterol are essential for cellular function. Cholesterol is a major lipid with multiple roles in membrane stability, signaling, or as a precursor for other molecules. Because of the structural similarity of the sterols involved in the biosynthesis, their accurate identification and quantification is still challenging. Moreover, the huge difference in the concentration of cholesterol and its precursors can cause interferences during the detection. To overcome these problems, a heart-cut liquid chromatographic method was developed by evaluating 38 different columns to achieve optimal separation. The method efficiently separates all sterol biosynthesis intermediates, with detection limits in the low nmol/L-range and an upper limit of quantification of 9 mmol/L for cholesterol by using triple quadrupole mass spectrometric detection. Investigation of lung carcinoma cells treated with statins demonstrated the capability to detect a biological response, showing inhibition of sterol synthesis. This technique offers a robust tool for studying cholesterol biosynthesis and its role in disease.

Methyl-β-cyclodextrin Enhances Tumor Cellular Uptake and Accumulation of α-Linolenic Acid-Paclitaxel Conjugate Nanoparticles

Improving nanomedicine uptake by tumor cells is key to achieving intracellular drug delivery. In this study, we found that methyl-β-cyclodextrin (MβCD) can significantly promote the intracellular accumulation of nanoparticulated α-linolenic acid-paclitaxel conjugates (ALA-PTX NPs) via enhanced clathrin-mediated endocytosis and limited degradation in lysosomes. Our in vitro results indicated that MβCD not only reduced the plasma membrane cholesterol content and increased plasma membrane fluidity, leading to ALA-PTX NPs being more easily incorporated into the plasma membrane, further enhancing membrane fluidity and making the plasma membrane more susceptible to tensile deformation, forming intracellular vesicles to enhance ALA-PTX NP cellular uptake, but also destroyed lysosomes and then limited ALA-PTX NPs' degradation in lysosomes. In HepG2 tumor-bearing mice, MβCD was also able to enhance the antitumor activity of ALA-PTX NPs in vivo. Moreover, we found that MβCD specifically promoted PUFA-paclitaxel conjugate NP cellular uptake. The cellular uptake of PTX liposome which shares an endocytosis pathway with ALA-PTX NPs could be enhanced by MβCD combined with ALA or ALA-PTX NPs. Therefore, we suggested that MβCD combined with polyunsaturated fatty acid-conjugation would be an effective strategy for improving intracellular delivery of nanoparticulated chemotherapeutic drugs used for combination administration to enhance antitumor efficiency.

Osteoblast Growth in Quaternized Silicon Carbon Nitride Coatings for Dental Implants

The demand for dental implants has increased, establishing them as the standard of care for replacing missing teeth. Several factors contribute to the success or failure of an implant post-placement. Modifications to implant surfaces can enhance the biological interactions between bone cells and the implant, promoting better outcomes. Surface coatings have been developed to electrochemically alter implant surfaces, aiming to reduce healing time, enhance bone growth, and prevent bacterial adhesion. Quaternized silicon carbon nitride (QSiCN) is a novel material with unique electrochemical and biological properties. This study aimed to assess the influence of QSiCN, silicon carbide nitride (SiCN), and silicon carbide (SiC) coatings on the viability of osteoblast cells on nanostructured titanium surfaces. The experiment utilized thirty-two titanium sheets with anodized TiO2 nanotubes featuring nanotube diameters of 50 nm and 150 nm. These sheets were divided into eight groups (n = 4): QSiCN-coated 50 nm, QSiCN-coated 150 nm, SiCN-coated 50 nm, SiCN-coated 150 nm, SiC-coated 50 nm, SiC-coated 150 nm, non-coated 50 nm, and non-coated 150 nm. Preosteoblast MC3T3-E1 Subclone 4 cells (ATCC, USA) were used to evaluate osteoblast viability. After three days of cell growth, samples were assessed using scanning electron microscopy (SEM). The results indicated that QSiCN coatings significantly increased osteoblast proliferation (p < 0.005) compared to other groups. The enhanced cell adhesion observed with QSiCN coatings is likely due to the positive surface charge imparted by N+.

Precise targeting of lipid metabolism in the era of immuno-oncology and the latest advances in nano-based drug delivery systems for cancer therapy

Over the past decade, research has increasingly identified unique dysregulations in lipid metabolism within the tumor microenvironment (TME). Lipids, diverse biomolecules, not only constitute biological membranes but also function as signaling molecules and energy sources. Enhanced synthesis or uptake of lipids in the TME significantly promotes tumorigenesis and proliferation. Moreover, lipids secreted into the TME influence tumor-resident immune cells (TRICs), thereby aiding tumor survival against chemotherapy and immunotherapy. This review aims to highlight recent advancements in understanding lipid metabolism in both tumor cells and TRICs, with a particular emphasis on exogenous lipid uptake and endogenous lipid de novo synthesis. Targeting lipid metabolism for intervention in anticancer therapies offers a promising therapeutic avenue for cancer treatment. Nano-drug delivery systems (NDDSs) have emerged as a means to maximize anti-tumor effects by rewiring tumor metabolism. This review provides a comprehensive overview of recent literature on the development of NDDSs targeting tumor lipid metabolism, particularly in the context of tumor immunotherapy. It covers four key aspects: reprogramming lipid uptake, reprogramming lipolysis, reshaping fatty acid oxidation (FAO), and reshuffling lipid composition on the cell membrane. The review concludes with a discussion of future prospects and challenges in this burgeoning field of research.

The role of ferroptosis resistance in lymph-associated tumour metastasis

Tumour metastasis is a crucial factor in determining clinically challenging tumours. In this respect, the lymphatic system may act as potential entry portals for tumour metastasis, whilst, clinical detection of tumour-infiltrated lymph nodes also indicates poorer prognosis and higher metastatic risk. Whether tumour cells gain ferroptosis resistance in lymph that make them exhibit a stronger propensity for lymphatic dissemination compared to hematogenous spread might be a breakthrough for elucidating lymph-associated tumour metastasis. This review discusses how the lymphatic system endows tumour cells with ferroptosis resistance character, which makes them more propensity for lymph node pre-metastasis and distant metastasis through lymphatic circulation. Comprehensively considering the distinct structure and property of lymph and the unique metabolic characteristics of tumours, all of the lymphatic vessels, intestinal lymph and lymph nodes collectively manipulate an intricate interaction with the hematogenous system and afford substances exchange with tumour cells and extracellular vesicles, upon which make a ferroptosis resistant microenvironment for subsequent metastasis in distant organs and lymph nodes.

Cholesterol Depletion-Enhanced Ferroptosis and Immunotherapy via Engineered Nanozyme

Ferroptosis, an iron- and reactive oxygen species (ROS)-dependent cell death, holds significant promise for tumor therapy due to its ability to induce lipid peroxidation (LPO) and trigger antitumor immune responses. However, elevated cholesterol levels in cancer cells impede ferroptosis and compromise immune function. Here, a novel nanozyme, Fe-MOF/CP, composed of iron metal-organic framework (Fe-MOF) nanoparticles loaded with cholesterol oxidase and PEGylation for integrated ferroptosis and immunotherapy is introduced. Fe-MOF/CP depletes cholesterol and generates hydrogen peroxide, enhancing ROS levels and inducing LPO, thereby promoting ferroptosis. This process disrupts lipid raft integrity and downregulates glutathione peroxidase 4 and ferroptosis suppressor protein 1, further facilitating ferroptosis. Concurrently, Fe-MOF/CP augments immunogenic cell death, reduces programmed death-ligand 1 expression, and revitalizes exhausted CD8+ T cells. In vivo studies demonstrate significant therapeutic efficacy in abscopal, metastasis, and recurrent tumor models, highlighting the robust antitumor immune responses elicited by Fe-MOF/CP. This study underscores the potential of Fe-MOF/CP as a multifunctional therapeutic agent that combines ferroptosis and immunotherapy, offering a promising strategy for effective and durable cancer treatment.

ACSL4-mediated lipid rafts prevent membrane rupture and inhibit immunogenic cell death in melanoma

Chemotherapy including platinum-based drugs are a possible strategy to enhance the immune response in advanced melanoma patients who are resistant to immune checkpoint blockade (ICB) therapy. However, the immune-boosting effects of these drugs are a subject of controversy, and their impact on the tumor microenvironment are poorly understood. In this study, we discovered that lipid peroxidation (LPO) promotes the formation of lipid rafts in the membrane, which mediated by Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) impairs the sensitivity of melanoma cells to platinum-based drugs. This reduction primarily occurs through the inhibition of immunogenic ferroptosis and pyroptosis by reducing cell membrane pore formation. By disrupting ACSL4-mediaged lipid rafts via the removal of membrane cholesterol, we promoted immunogenic cell death, transformed the immunosuppressive environment, and improved the antitumor effectiveness of platinum-based drugs and immune response. This disruption also helped reverse the decrease in CD8+ T cells while maintaining their ability to secrete cytokines. Our results reveal that ACSL4-dependent LPO is a key regulator of lipid rafts formation and antitumor immunity, and that disrupting lipid rafts has the potential to enhance platinum-based drug-induced immunogenic ferroptosis and pyroptosis in melanoma. This novel strategy may augment the antitumor immunity of platinum-based therapy and further complement ICB therapy.

Inhibition of PCSK9: A Promising Enhancer for Anti-PD-1/PD-L1 Immunotherapy

Immune checkpoint therapy, such as programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) blockade, has achieved remarkable results in treating various tumors. However, most cancer patients show a low response rate to PD-1/PD-L1 blockade, especially those with microsatellite stable/mismatch repair-proficient colorectal cancer subtypes, which indicates an urgent need for new approaches to augment the efficacy of PD-1/PD-L1 blockade. Cholesterol metabolism, which involves generating multifunctional metabolites and essential membrane components, is also instrumental in tumor development. In recent years, inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9), a serine proteinase that regulates cholesterol metabolism, has been demonstrated to be a method enhancing the antitumor effect of PD-1/PD-L1 blockade to some extent. Mechanistically, PCSK9 inhibition can maintain the recycling of major histocompatibility protein class I, promote low-density lipoprotein receptor-mediated T-cell receptor recycling and signaling, and modulate the tumor microenvironment (TME) by affecting the infiltration and exclusion of immune cells. These mechanisms increase the quantity and enhance the antineoplastic effect of cytotoxic T lymphocyte, the main functional immune cells involved in anti-PD-1/PD-L1 immunotherapy, in the TME. Therefore, combining PCSK9 inhibition therapy with anti-PD-1/PD-L1 immunotherapy may provide a novel option for improving antitumor effects and may constitute a promising research direction. This review concentrates on the relationship between PCSK9 and cholesterol metabolism, systematically discusses how PCSK9 inhibition potentiates PD-1/PD-L1 blockade for cancer treatment, and highlights the research directions in this field.

Cholesterol-ferroptosis nexus: Unveiling novel cancer therapeutic avenues

Ferroptosis, a novel form of regulated cell death characterized by iron-mediated lipid peroxidation, holds immense potential in cancer therapeutics due to its role in tumor progression and resistance. This review predominantly explores the intricate relationship between ferroptosis and cholesterol metabolism pathways, mainly focusing on the cholesterol biosynthesis pathway. This review highlights the therapeutic implications of targeting cholesterol metabolism pathways for cancer treatment by delving into the mechanisms underlying ferroptosis regulation. Strategies such as inhibiting HMG-CoA reductase and suppressing squalene synthesis offer promising avenues for inducing ferroptosis in cancer cells. Moreover, insights into targeting the 7-dehydrocholesterol pathway provide novel perspectives on modulating ferroptosis susceptibility and managing ferroptosis-associated diseases. Understanding the interplay between ferroptosis and cholesterol metabolism pathways underscores the potential of lipid metabolism modulation as an innovative therapeutic approach in cancer treatment.

Celastrus orbiculatus Thunb. extracts and celastrol alleviate NAFLD by preserving mitochondrial function through activating the FGF21/AMPK/PGC-1α pathway

Objective

Non-alcoholic fatty liver disease (NAFLD) is a prevalent chronic liver disease globally, characterized by the accumulation of lipids, oxidative stress, and mitochondrial dysfunction in the liver. Celastrus orbiculatus Thunb. (COT) and its active compound celastrol (CEL) have demonstrated antioxidant and anti-inflammatory properties. Our prior research has shown the beneficial effects of COT in mitigating NAFLD induced by a high-fat diet (HFD) in guinea pigs by reducing hepatic lipid levels and inhibiting oxidative stress. This study further assessed the effects of COT on NAFLD and explored its underlying mitochondria-related mechanisms.

Methods

COT extract or CEL was administered as an intervention in C57BL/6J mice fed a HFD or in HepG2 cells treated with sodium oleate. Oral glucose tolerance test, biochemical parameters including liver enzymes, blood lipid, and pro-inflammatory factors, and steatosis were evaluated. Meanwhile, mitochondrial ultrastructure and indicators related to oxidative stress were tested. Furthermore, regulators of mitochondrial function were measured using RT-qPCR and Western blot.

Results

The findings demonstrated significant reductions in hepatic steatosis, oxidative stress, and inflammation associated with NAFLD in both experimental models following treatment with COT extract or CEL. Additionally, improvements were observed in mitochondrial structure, ATP content, and ATPase activity. This improvement can be attributed to the significant upregulation of mRNA and protein expression levels of key regulators including FGF21, AMPK, PGC-1α, PPARγ, and SIRT3.

Conclusion

These findings suggest that COT may enhance mitochondrial function by activating the FGF21/AMPK/PGC-1α signaling pathway to mitigate NAFLD, which indicated that COT has the potential to target mitochondria and serve as a novel therapeutic option for NAFLD.

Current Progress of Ferroptosis Study in Hepatocellular Carcinoma

Ferroptosis, an emerging type of programmed cell death, is initiated by iron-dependent and excessive ROS-mediated lipid peroxidation, which eventually leads to plasma membrane rupture and cell death. Many canonical signalling pathways and biological processes are involved in ferroptosis. Furthermore, cancer cells are more susceptible to ferroptosis due to the high load of ROS and unique metabolic characteristics, including iron requirements. Recent investigations have revealed that ferroptosis plays a crucial role in the progression of tumours, especially HCC. Specifically, the induction of ferroptosis can not only inhibit the growth of hepatoma cells, thereby reversing tumorigenesis, but also improves the efficacy of immunotherapy and enhances the antitumour immune response. Therefore, triggering ferroptosis has become a new therapeutic strategy for cancer therapy. In this review, we summarize the characteristics of ferroptosis based on its underlying mechanism and role in HCC and provide possible therapeutic applications.

Ferroptosis: principles and significance in health and disease

Ferroptosis, an iron-dependent form of cell death characterized by uncontrolled lipid peroxidation, is governed by molecular networks involving diverse molecules and organelles. Since its recognition as a non-apoptotic cell death pathway in 2012, ferroptosis has emerged as a crucial mechanism in numerous physiological and pathological contexts, leading to significant therapeutic advancements across a wide range of diseases. This review summarizes the fundamental molecular mechanisms and regulatory pathways underlying ferroptosis, including both GPX4-dependent and -independent antioxidant mechanisms. Additionally, we examine the involvement of ferroptosis in various pathological conditions, including cancer, neurodegenerative diseases, sepsis, ischemia-reperfusion injury, autoimmune disorders, and metabolic disorders. Specifically, we explore the role of ferroptosis in response to chemotherapy, radiotherapy, immunotherapy, nanotherapy, and targeted therapy. Furthermore, we discuss pharmacological strategies for modulating ferroptosis and potential biomarkers for monitoring this process. Lastly, we elucidate the interplay between ferroptosis and other forms of regulated cell death. Such insights hold promise for advancing our understanding of ferroptosis in the context of human health and disease.

ALOX15B controls macrophage cholesterol homeostasis via lipid peroxidation, ERK1/2 and SREBP2

Macrophage cholesterol homeostasis is crucial for health and disease and has been linked to the lipid-peroxidizing enzyme arachidonate 15-lipoxygenase type B (ALOX15B), albeit molecular mechanisms remain obscure. We performed global transcriptome and immunofluorescence analysis in ALOX15B-silenced primary human macrophages and observed a reduction of nuclear sterol regulatory element-binding protein (SREBP) 2, the master transcription factor of cellular cholesterol biosynthesis. Consequently, SREBP2-target gene expression was reduced as were the sterol biosynthetic intermediates desmosterol and lathosterol as well as 25- and 27-hydroxycholesterol. Mechanistically, suppression of ALOX15B reduced lipid peroxidation in primary human macrophages and thereby attenuated activation of mitogen-activated protein kinase ERK1/2, which lowered SREBP2 abundance and activity. Low nuclear SREBP2 rendered both, ALOX15B-silenced and ERK1/2-inhibited macrophages refractory to SREBP2 activation upon blocking the NPC intracellular cholesterol transporter 1. These studies suggest a regulatory mechanism controlling macrophage cholesterol homeostasis based on ALOX15B-mediated lipid peroxidation and concomitant ERK1/2 activation.

Regulation of ferroptosis by nanotechnology for enhanced cancer immunotherapy

INTRODUCTION

This review explores the innovative intersection of ferroptosis, a form of iron-dependent cell death, with cancer immunotherapy. Traditional cancer treatments face limitations in efficacy and specificity. Ferroptosis as a new paradigm in cancer biology, targets metabolic peculiarities of cancer cells and may potentially overcome such limitations, enhancing immunotherapy.

AREA COVERED

This review centers on the regulation of ferroptosis by nanotechnology to augment immunotherapy. It explores how nanoparticle-modulated ferroptotic cancer cells impact the TME and immune responses. The dual role of nanoparticles in modulating immune response through ferroptosis are also discussed. Additionally, it investigates how nanoparticles can be integrated with various immunotherapeutic strategies, to optimize ferroptosis induction and cancer treatment efficacy. The literature search was conducted using PubMed and Google Scholar, covering articles published up to March 2024.

EXPERT OPINION

The manuscript underscores the promising yet intricate landscape of ferroptosis in immunotherapy. It emphasizes the need for a nuanced understanding of ferroptosis' impact on immune cells and the TME to develop more effective cancer treatments, highlighting the potential of nanoparticles in enhancing the efficacy of ferroptosis and immunotherapy. It calls for deeper exploration into the molecular mechanisms and clinical potential of ferroptosis to fully harness its therapeutic benefits in immunotherapy.

Cell Membrane-Targeting Type I/II Photodynamic Therapy Combination with FSP1 Inhibition for Ferroptosis-Enhanced Photodynamic Immunotherapy

An imbalance in reactive oxygen species (ROS) levels in tumor cells can result in the accumulation of lipid peroxide (LPO) which can induce ferroptosis. Moreover, elevated ROS levels in tumors present a chance to develop ROS-based cancer therapeutics including photodynamic therapy (PDT) and ferroptosis. However, their anticancer efficacies are compromised by insufficient oxygen levels and inherent cellular ROS regulatory mechanism. Herein, a cell membrane-targeting photosensitizer, TBzT-CNQi, which can generate 1O2, •OH, and O2 •- via type I/II process to induce a high level of LPO for potent ferroptosis and photodynamic therapy is developed. The FSP1 inhibitor (iFSP1) is incorporated with TBzT-CNQi to downregulate FSP1 expression, lower the intracellular CoQ10 content, induce a high level of LPO, and activate initial tumor immunogenic ferroptosis. In vitro and in vivo experiments demonstrate that the cell membrane-targeting type I/II PDT combination with FSP1 inhibition can evoke strong ICD and activate the immune response, which subsequently promotes the invasion of CD8+ T cells infiltration, facilitates the dendritic cell maturation, and decreases the tumor infiltration of tumor-associated macrophages. The study indicates that the combination of cell membrane-targeting type I/II PDT and FSP1 inhibition holds promise as a potential strategy for ferroptosis-enhanced photodynamic immunotherapy of hypoxia tumors.

Ferroptosis and its role in gastric and colorectal cancers

Ferroptosis is a novel mechanism of programmed cell death, characterized by intracellular iron overload, intensified lipid peroxidation, and abnormal accumulation of reactive oxygen species, which ultimately resulting in cell membrane impairment and demise. Research has revealed that cancer cells exhibit a greater demand for iron compared to normal cells, indicating a potential susceptibility of cancer cells to ferroptosis. Stomach and colorectal cancers are common gastrointestinal malignancies, and their elevated occurrence and mortality rates render them a global health concern. Despite significant advancements in medical treatments, certain unfavorable consequences and drug resistance persist. Consequently, directing attention towards the phenomenon of ferroptosis in gastric and colorectal cancers holds promise for enhancing therapeutic efficacy. This review aims to elucidate the intricate cellular metabolism associated with ferroptosis, encompassing lipid and amino acid metabolism, as well as iron metabolic processes. Furthermore, the significance of ferroptosis in the context of gastric and colorectal cancer is thoroughly examined and discussed.

Nanoparticle Targeting in Chemo-Resistant Ovarian Cancer Reveals Dual Axis of Therapeutic Vulnerability Involving Cholesterol Uptake and Cell Redox Balance

Platinum (Pt)-based chemotherapy is the main treatment for ovarian cancer (OC); however, most patients develop Pt resistance (Pt-R). This work shows that Pt-R OC cells increase intracellular cholesterol through uptake via the HDL receptor, scavenger receptor type B-1 (SR-B1). SR-B1 blockade using synthetic cholesterol-poor HDL-like nanoparticles (HDL NPs) diminished cholesterol uptake leading to cell death and inhibition of tumor growth. Reduced cholesterol accumulation in cancer cells induces lipid oxidative stress through the reduction of glutathione peroxidase 4 (GPx4) leading to ferroptosis. In turn, GPx4 depletion induces decreased cholesterol uptake through SR-B1 and re-sensitizes OC cells to Pt. Mechanistically, GPx4 knockdown causes lower expression of the histone acetyltransferase EP300, leading to reduced deposition of histone H3 lysine 27 acetylation (H3K27Ac) on the sterol regulatory element binding transcription factor 2 (SREBF2) promoter and suppressing expression of this key transcription factor involved in the regulation of cholesterol metabolism. SREBF2 downregulation leads to decreased SR-B1 expression and diminished cholesterol uptake. Thus, chemoresistance and cancer cell survival under high ROS burden obligates high GPx4 and SR-B1 expression through SREBF2. Targeting SR-B1 to modulate cholesterol uptake inhibits this axis and causes ferroptosis in vitro and in vivo in Pt-R OC.

Metabolism-regulated ferroptosis in cancer progression and therapy

Cancer metabolism mainly includes carbohydrate, amino acid and lipid metabolism, each of which can be reprogrammed. These processes interact with each other to adapt to the complicated microenvironment. Ferroptosis is a regulated cell death induced by iron-dependent lipid peroxidation, which is morphologically different from apoptosis, necrosis, necroptosis, pyroptosis, autophagy-dependent cell death and cuprotosis. Cancer metabolism plays opposite roles in ferroptosis. On the one hand, carbohydrate metabolism can produce NADPH to maintain GPX4 and FSP1 function, and amino acid metabolism can provide substrates for synthesizing GPX4; on the other hand, lipid metabolism might synthesize PUFAs to trigger ferroptosis. The mechanisms through which cancer metabolism affects ferroptosis have been investigated extensively for a long time; however, some mechanisms have not yet been elucidated. In this review, we summarize the interaction between cancer metabolism and ferroptosis. Importantly, we were most concerned with how these targets can be utilized in cancer therapy.

Lipid Peroxidation Drives Liquid-Liquid Phase Separation and Disrupts Raft Protein Partitioning in Biological Membranes

The peroxidation of membrane lipids by free radicals contributes to aging, numerous diseases, and ferroptosis, an iron-dependent form of cell death. Peroxidation changes the structure and physicochemical properties of lipids, leading to bilayer thinning, altered fluidity, and increased permeability of membranes in model systems. Whether and how lipid peroxidation impacts the lateral organization of proteins and lipids in biological membranes, however, remains poorly understood. Here, we employ cell-derived giant plasma membrane vesicles (GPMVs) as a model to investigate the impact of lipid peroxidation on ordered membrane domains, often termed membrane rafts. We show that lipid peroxidation induced by the Fenton reaction dramatically enhances the phase separation propensity of GPMVs into coexisting liquid-ordered (Lo) and liquid-disordered (Ld) domains and increases the relative abundance of the disordered phase. Peroxidation also leads to preferential accumulation of peroxidized lipids and 4-hydroxynonenal (4-HNE) adducts in the disordered phase, decreased lipid packing in both Lo and Ld domains, and translocation of multiple classes of raft proteins out of ordered domains. These findings indicate that the peroxidation of plasma membrane lipids disturbs many aspects of membrane rafts, including their stability, abundance, packing, and protein and lipid composition. We propose that these disruptions contribute to the pathological consequences of lipid peroxidation during aging and disease and thus serve as potential targets for therapeutic intervention.

Analyzing the impact of metabolism on immune cells in tumor microenvironment to promote the development of immunotherapy

Tumor metabolism and tumor immunity are inextricably linked. Targeting the metabolism of tumors is a point worth studying in tumor immunotherapy. Recently, the influence of the metabolism of tumors and immune cells on the occurrence, proliferation, metastasis, and prognosis of tumors has attracted more attention. Tumor tissue forms a specific tumor microenvironment (TME). In addition to tumor cells, there are also immune cells, stromal cells, and other cells in TME. To adapt to the environment, tumor cells go through the metabolism reprogramming of various substances. The metabolism reprogramming of tumor cells may further affect the formation of the tumor microenvironment and the function of a variety of cells, especially immune cells, eventually promoting tumor development. Therefore, it is necessary to study the metabolism of tumor cells and its effects on immune cells to guide tumor immunotherapy. Inhibiting tumor metabolism may restore immune balance and promote the immune response in tumors. This article will describe glucose metabolism, lipid metabolism, amino acid metabolism, and immune cells in tumors. Besides, the impact of metabolism on the immune cells in TME is also discussed for analyzing and exploring tumor immunotherapy.

How do different lipid peroxidation mechanisms contribute to ferroptosis?

Lipid peroxidation is the driver of ferroptotic cell death. However, nonconjugated and conjugated polyunsaturated fatty acids potentiate ferroptosis differently, while some isoprenoid-derived lipids inhibit ferroptosis despite being highly oxidizable. In this perspective, we propose that different oxidation mechanisms and products contribute to the discrepancies in the lipids' potency in modulating ferroptosis. We first discuss the relative reactivities of various lipids toward two rate-determining free radical propagating mechanisms, hydrogen atom transfer (HAT) and peroxyl radical addition (PRA), and the resulting differential product profiles. We then discuss the role and regulation of lipid peroxidation in ferroptosis and the potential contributions of different oxidation products, such as truncated lipids and lipid electrophiles, from HAT and PRA mechanisms to the execution of ferroptosis. Lastly, we offer our perspective on the remaining questions to fully understand the process from lipid peroxidation to ferroptosis.

Lipid peroxidation: Reactive carbonyl species, protein/DNA adducts, and signaling switches in oxidative stress and cancer

Under the exposure of lipids to reactive oxygen species (ROS), lipid peroxidation proceeds non-enzymatically and generates an extremely heterogeneous mixture of reactive carbonyl species (RCS). Among them, HNE, HHE, MDA, methylglyoxal, glyoxal, and acrolein are the most studied and/or abundant ones. Over the last decades, significant progress has been achieved in understanding mechanisms of RCS generation, protein/DNA adduct formation, and their identification and quantification in biological samples. In our review, we critically discuss the advancements in understanding the roles of RCS-induced protein/DNA modifications in signaling switches to provide adaptive cell response under physiological and oxidative stress conditions. At non-toxic concentrations, RCS modify susceptible Cys residue in c-Src to activate MAPK signaling and Cys, Lys, and His residues in PTEN to cause its reversible inactivation, thereby stimulating PI3K/PKB(Akt) pathway. RCS toxic concentrations cause irreversible Cys modifications in Keap1 and IKKβ followed by stabilization of Nrf2 and activation of NF-κB, respectively, for their nuclear translocation and antioxidant gene expression. Dysregulation of these mechanisms causes diseases including cancer. Alterations in RCS, RCS detoxifying enzymes, RCS-modified protein/DNA adducts, and signaling pathways have been implicated in various cancer types.

Effects of Indoor Dust Exposure on Lung Cells: Association of Chemical Composition with Phenotypic and Lipid Changes in a 3D Lung Cancer Cell Model

Indoor dust is a key contributor to the global human exposome in urban areas since the population develops most of its activities in private and public buildings. To gain insight into the health risks associated with this chronic exposure, it is necessary to characterize the chemical composition of dust and understand its biological impacts using reliable physiological models. The present study investigated the biological effects of chemically characterized indoor dust extracts using three-dimensional (3D) lung cancer cell cultures combining phenotypic and lipidomic analyses. Apart from the assessment of cell viability, reactive oxygen species (ROS) induction, and interleukin-8 release, lipidomics was applied to capture the main lipid changes induced as a cellular response to the extracted dust compounds. The application of chemometric tools enabled the finding of associations between chemical compounds present in dust and lipidic and phenotypic profiles in the cells. This study contributes to a better understanding of the toxicity mechanisms associated with exposure to chemical pollutants present in indoor dust.

The combined characteristics of cholesterol metabolism and the immune microenvironment may serve as valuable biomarkers for both the prognosis and treatment of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) being a complex disease, commonly exhibits multifaceted presentations, rendering its treatment challenging and necessitating specific approaches. The tumor immune microenvironment is crucial in cancer treatment, and cholesterol metabolism is a key component that helps cells grow and produce vital metabolites. However, the reprogramming of cholesterol metabolism in the tumor microenvironment (TME) can promote HCC development, and cancer classifiers relating to cholesterol metabolism are currently limited. Despite significant progress, further research is needed to improve early detection, liver function, and treatment options to improve patient outcomes.

Methods

To evaluate the expression abundance of tumor immune microenvironment (TIME) and cholesterol metabolism in 8 types of liver cancer cells, we comprehensively evaluated the immune cell composition, extracellular matrix alterations, and activity of relevant signaling pathways in the TIME through nine liver cancer patients, stromal scoring, immune scoring, tumor purity scoring, immune infiltration analysis, and pathway enrichment. Subsequently, we utilized machine learning techniques to construct prognostic models for both cholesterol metabolism and the tumor immune microenvironment, further exploring the tumor mutation burden, immune infiltration levels, and drug sensitivity in different subtypes of HCC patients.

Results

Our study constructed three cancer screening models to identify HCC patients with high cholesterol metabolism and low TIME, who have a poorer prognosis. On the contrary, patients with low cholesterol metabolism and high TIME often have better prognosis. Furthermore, we identified chemical compounds, such as BPD-00008900, ML323, Doramapimod, and AZD2014, which display better chemotherapy results for high-risk patients in specific sub-groups.

Cholesterol mediated ferroptosis suppression reveals essential roles of Coenzyme Q and squalene

Recent findings have shown that fatty acid metabolism is profoundly involved in ferroptosis. However, the role of cholesterol in this process remains incompletely understood. In this work, we show that modulating cholesterol levels changes vulnerability of cells to ferroptosis. Cholesterol alters metabolic flux of the mevalonate pathway by promoting Squalene Epoxidase (SQLE) degradation, a rate limiting step in cholesterol biosynthesis, thereby increasing both CoQ10 and squalene levels. Importantly, whereas inactivation of Farnesyl-Diphosphate Farnesyltransferase 1 (FDFT1), the branch point of cholesterol biosynthesis pathway, exhibits minimal effect on ferroptosis, simultaneous inhibition of both CoQ10 and squalene biosynthesis completely abrogates the effect of cholesterol. Mouse models of ischemia-reperfusion and doxorubicin induced hepatoxicity confirm the protective role of cholesterol in ferroptosis. Our study elucidates a potential role of ferroptosis in diseases related to dysregulation of cholesterol metabolism and suggests a possible therapeutic target that involves ferroptotic cell death.

Lipid peroxidation drives liquid-liquid phase separation and disrupts raft protein partitioning in biological membranes

The peroxidation of membrane lipids by free radicals contributes to aging, numerous diseases, and ferroptosis, an iron-dependent form of cell death. Peroxidation changes the structure, conformation and physicochemical properties of lipids, leading to major membrane alterations including bilayer thinning, altered fluidity, and increased permeability. Whether and how lipid peroxidation impacts the lateral organization of proteins and lipids in biological membranes, however, remains poorly understood. Here, we employ cell-derived giant plasma membrane vesicles (GPMVs) as a model to investigate the impact of lipid peroxidation on ordered membrane domains, often termed membrane rafts. We show that lipid peroxidation induced by the Fenton reaction dramatically enhances phase separation propensity of GPMVs into co-existing liquid ordered (raft) and liquid disordered (non-raft) domains and increases the relative abundance of the disordered, non-raft phase. Peroxidation also leads to preferential accumulation of peroxidized lipids and 4-hydroxynonenal (4-HNE) adducts in the disordered phase, decreased lipid packing in both raft and non-raft domains, and translocation of multiple classes of proteins out of rafts. These findings indicate that peroxidation of plasma membrane lipids disturbs many aspects of membrane rafts, including their stability, abundance, packing, and protein and lipid composition. We propose that these disruptions contribute to the pathological consequences of lipid peroxidation during aging and disease, and thus serve as potential targets for therapeutic intervention.

Physicochemical characterization, in vitro and in vivo evaluation of chitosan/carrageenan encumbered with Imatinib mesylate-polysarcosine nanoparticles for sustained drug release and enhanced colorectal cancer targeted therapy

The objective of this investigation was to fabricate nanoparticles consisting of Imatinib mesylate-poly sarcosine-loaded chitosan/carrageenan in order to attain prolonged drug release and efficacious therapy for colorectal cancer. The study involved the synthesis of nanoparticles through the utilisation of ionic complexation and nanoprecipitation techniques. The subsequent nanoparticles were subjected to an assessment of their physicochemical characteristics, anti-cancer efficacy using HCT116 cell line, and acute toxicity. The present study examined two distinct nanoparticle formulations, namely IMT-PSar-NPs and CS-CRG-IMT-NPs, with respect to their particle size, zeta potential, and morphology. Both formulations demonstrated satisfactory characteristics, as they displayed consistent and prolonged drug release for a duration of 24 h, with the highest level of release occurring at a pH of 5.5. The efficacy and safety of IMT-PSar-NPs and CS-CRG-IMT-PSar-NPs nanoparticles were evaluated through various tests including in vitro cytotoxicity, cellular uptake, apoptosis, scratch test, cell cycle analysis, MMP & ROS estimate, acute toxicity, and stability tests. The results suggest that these nanoparticles were well fabricated and have promising potential for in vivo applications. The prepared polysaccharide nanoparticles have great potential for active targeting and could potentially reduce dose-dependent toxicity in the treatment of colon cancer.

Celastrol functions as an emerging manager of lipid metabolism: Mechanism and therapeutic potential

Lipid metabolism disorders are pivotal in the development of various lipid-related diseases, such as obesity, atherosclerosis, non-alcoholic fatty liver disease, type 2 diabetes, and cancer. Celastrol, a bioactive compound extracted from the Chinese herb Tripterygium wilfordii Hook F, has recently demonstrated potent lipid-regulating abilities and promising therapeutic effects for lipid-related diseases. There is substantial evidence indicating that celastrol can ameliorate lipid metabolism disorders by regulating lipid profiles and related metabolic processes, including lipid synthesis, catabolism, absorption, transport, and peroxidation. Even wild-type mice show augmented lipid metabolism after treatment with celastrol. This review aims to provide an overview of recent advancements in the lipid-regulating properties of celastrol, as well as to elucidate its underlying molecular mechanisms. Besides, potential strategies for targeted drug delivery and combination therapy are proposed to enhance the lipid-regulating effects of celastrol and avoid the limitations of its clinical application.

Nanometer Resolution Mass Spectro-Microtomography for In-Depth Anatomical Profiling of Single Cells

Visually identifying the molecular changes in single cells is of great importance for unraveling fundamental cellular functions as well as disease mechanisms. Herein, we demonstrated a mass spectro-microtomography with an optimal voxel resolution of ∼300 × 300 × 25 nm³, which enables three-dimensional tomography of chemical substances in single cells. This mass imaging method allows for the distinguishment of abundant endogenous and exogenous molecules in subcellular structures. Combined with statistical analysis, we demonstrated this method for spatial metabolomics analysis of drug distribution and subsequent molecular damages caused by intracellular drug action. More interestingly, thanks to the nanoprecision ablation depth (∼12 nm), we realized metabolomics profiling of cell membrane without the interference of cytoplasm and improved the distinction of cancer cells from normal cells. Our current method holds great potential to be a powerful tool for spatially resolved single-cell metabolomics analysis of chemical components during complex biological processes.