Suppression of Energy Metabolism in Cancer Cells with Nutrient-Sensing Nanodrugs

International Union of Basic and Clinical Pharmacology. CXIX. Fundamental insights and clinical relevance regarding the carnitine palmitoyltransferase family of enzymes

The carnitine palmitoyltransferases (CPTs) play a key role in controlling the oxidation of long-chain fatty acids and are potential therapeutic targets for diseases with a strong metabolic component, such as obesity, diabetes, and cancer. Four distinct proteins are CPT1A, CPT1B, CPT1C, and CPT2, differing in tissue expression and catalytic activity. CPT1s are finely regulated by malonyl-CoA, a metabolite whose intracellular levels reflect the cell's nutritional state. Although CPT1C does not exhibit significant catalytic activity, it is capable of modulating the functioning of other neuronal proteins. Structurally, all CPTs share a Y-shaped catalytic tunnel that allows the entry of 2 substrates and accommodation of the acyl group in a hydrophobic pocket. Several molecules targeting these enzymes have been described, some showing potential in normalizing blood glucose levels in diabetic patients, and others that, through a central mechanism, are anorexigenic and enhance energy expenditure. However, given the critical roles that CPTs play in certain tissues, such as the heart, liver, and brain, it is essential to fully understand the differences between the various isoforms. We analyze in detail the structure of these proteins, their cellular and physiological functions, and their potential as therapeutic targets in diseases such as obesity, diabetes, and cancer. We also describe drugs identified to date as having inhibitory or activating capabilities for these proteins. This knowledge will support the design of new drugs specific to each isoform, and the development of nanomedicines that can selectively target particular tissues or cells. SIGNIFICANCE STATEMENT: Carnitine palmitoyltransferase (CPT) proteins, as gatekeepers of fatty acid oxidation, have great potential as pharmacological targets to treat metabolic diseases like obesity, diabetes, and cancer. In recent years, significant progress has been made in understanding the 3-dimensional structure of CPTs and their pathophysiological functions. A deeper understanding of the differences between the various CPT family members will enable the design of selective drugs and therapeutic approaches with fewer side effects.

Anti-Tumor Strategies Targeting Nutritional Deprivation: Challenges and Opportunities

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

Effects of the periodic fasting-mimicking diet on health, lifespan, and multiple diseases: a narrative review and clinical implications

Dietary restriction and fasting have been recognized for their beneficial effects on health and lifespan and their potential application in managing chronic metabolic diseases. However, long-term adherence to strict dietary restrictions and prolonged fasting poses challenges for most individuals and may lead to unhealthy rebound eating habits, negatively affecting overall health. As a result, a periodic fasting-mimicking diet (PFMD), involving cycles of fasting for 2 or more days while ensuring basic nutritional needs are met within a restricted caloric intake, has gained widespread acceptance. Current research indicates that a PFMD can promote stem cell regeneration, suppress inflammation, extend the health span of rodents, and improve metabolic health, among other effects. In various disease populations such as patients with diabetes, cancer, multiple sclerosis, and Alzheimer's disease, a PFMD has shown efficacy in alleviating disease symptoms and improving relevant markers. After conducting an extensive analysis of available research on the PFMD, it is evident that its advantages and potential applications are comparable to other fasting methods. Consequently, it is proposed in this review that a PFMD has the potential to fully replace water-only or very-low-energy fasting regimens and holds promise for application across multiple diseases.

Biomimetic Nanovesicles Synergize with Short-Term Fasting for Enhanced Chemotherapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive and lethal subtype of breast cancer among women. Chemotherapy acts as the standard regimen for TNBC treatment but suffers from limited drug accumulation in tumor regions and undesired side effects. Herein, we developed a synergistic strategy by combining a red blood cell (RBC) membrane-liposome hybrid nanovesicle with short-term fasting (STF) for improved chemotherapy of TNBC. The biomimetic nanovesicles exhibited reduced phagocytosis by macrophages while displaying a significant increase in tumor cell uptake through caveolae/raft-mediated endocytosis under nutrient-deprivation conditions. Importantly, drug-loaded nanovesicles and STF treatment synergistically increased the cytotoxicity of tumor cells by inhibiting their cell cycles and aerobic glycolysis as well as amplifying the reactive oxygen species (ROS) and autophagosomes generation. In the STF-treated mice, biomimetic nanovesicles greatly improved the antitumor efficacy at a lower drug dosage and inhibited the undesired metastasis of TNBC. Overall, we demonstrated that biomimetic nanovesicles synergizing with STF therapy serve as a promising therapeutic strategy for enhanced chemotherapy of malignant TNBC.

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.

Reprogramming the immunosuppressive tumor microenvironment through nanomedicine: an immunometabolism perspective

Increasing evidence indicates that immunotherapy is hindered by a hostile tumor microenvironment (TME) featured with deprivation of critical nutrients and pooling of immunosuppressive metabolites. Tumor cells and immunosuppressive cells outcompete immune effector cells for essential nutrients. Meanwhile, a wide range of tumor cell-derived toxic metabolites exerts negative impacts on anti-tumor immune response, diminishing the efficacy of immunotherapy. Nanomedicine with excellent targetability offers a novel approach to improving cancer immunotherapy via metabolically reprogramming the immunosuppressive TME. Herein, we review recent strategies of enhancing immunotherapeutic effects through rewiring tumor metabolism via nanomedicine. Attention is drawn on immunometabolic tactics for immune cells and stromal cells in the TME via nanomedicine. Additionally, we discuss future directions of developing metabolism-regulating nanomedicine for precise and efficacious cancer immunotherapy.

Fasting-Mimicking Diet Facilitates Anti-tumor Therapeutic Effects by Nutrient-Sensitive Nanocomposites

Cancer cells support their uncontrolled proliferation primarily by regulating energy metabolism. Inhibiting tumor growth by blocking the supply of nutrients is an effective treatment strategy. Fasting-mimicking diet (FMD), as a low-calorie, low-protein, low-sugar, high-fat diet, can effectively reduce the nutrient supply to tumor cells. However, the significant biological barrier presented by the tumor microenvironment imposes greater demands and challenges for drug design. This study constructs the multifunctional nanocomposite ZnFe2O4@TiO2@CHC@Orl-FA (ZTCOF), which has great potential to overcome the aforementioned drawbacks. ZnFe2O4@TiO2 could produce 1O2 with ultrasound, and stimulate the Fenton-like conversion of endogenous H2O2 to ·OH, achieving a combined therapeutic effect of sonodynamic therapy (SDT) and chemodynamic therapy (CDT). Orl (Orlistat) and CHC (α-cyano-4-hydroxycinnamic acid) not only block tumor cell energy metabolism but also increase sensitivity to reactive oxygen species, enhancing the cytotoxic effect on tumor cells. Furthermore, combining the treatment strategies with FMD condition control can further inhibit cancer cell energy metabolism, achieving significant synergistic anti-tumor therapy. Both in vitro and in vivo experiments confirm that ZTCOF with SDT/CDT/starvation can achieve effective tumor suppression and destruction. This work provides theoretical and technical support for anti-tumor multimodal synergistic therapy.

Nanomedomics

Nanomaterials have attractive physicochemical properties. A variety of nanomaterials such as inorganic, lipid, polymers, and protein nanoparticles have been widely developed for nanomedicine via chemical conjugation or physical encapsulation of bioactive molecules. Superior to traditional drugs, nanomedicines offer high biocompatibility, good water solubility, long blood circulation times, and tumor-targeting properties. Capitalizing on this, several nanoformulations have already been clinically approved and many others are currently being studied in clinical trials. Despite their undoubtful success, the molecular mechanism of action of the vast majority of nanomedicines remains poorly understood. To tackle this limitation, herein, this review critically discusses the strategy of applying multiomics analysis to study the mechanism of action of nanomedicines, named nanomedomics, including advantages, applications, and future directions. A comprehensive understanding of the molecular mechanism could provide valuable insight and therefore foster the development and clinical translation of nanomedicines.

Spatially modulated ablation driven by chaotic attractors in human lung epithelial cancer cells

A significant modification in photoinduced energy transfer in cancer cells is reported by the assistance of a dynamic modulation of the beam size of laser irradiation. Human lung epithelial cancer cells in monolayer form were studied. In contrast to the quantum and thermal ablation effect promoted by a standard focused Gaussian beam, a spatially modulated beam can caused around 15% of decrease in the ablation threshold and formation of a ring-shaped distribution of the photothermal transfer effect. Optical irradiation was conducted in A549 cells by a 532 nm single-beam emerging from a Nd:YVO4 system. Ablation effects derived from spatially modulated convergent waves were controlled by an electrically focus-tunable lens. The proposed chaotic behavior of the spatial modulation followed an Arneodo chaotic oscillator. Fractional dynamic thermal transport was analyzed in order to describe photoenergy in propagation through the samples. Immediate applications of chaos theory for developing phototechnology devices driving biological functions or phototherapy treatments can be considered.

Intelligent Delivery Systems in Tumor Metabolism Regulation: Exploring the Path Ahead

Cancer metabolism plays multifaceted roles in the initiation and progression of tumors, and interventions in metabolism are considered fundamental approaches for cancer control. Within the vast metabolic networks of tumors, there exist numerous potential therapeutic targets, intricately interconnected with each other and with signaling networks related to immunity, metastasis, drug resistance, and more. Based on the characteristics of the tumor microenvironment, constructing drug delivery systems for multi-level modulation of the tumor microenvironment is proven as an effective strategy for achieving multidimensional control of cancer. Consequently, this article summarizes several features of tumor metabolism to provide insights into recent advancements in intelligent drug delivery systems for achieving multi-level regulation of the metabolic microenvironment in cancer, with the aim of offering a novel paradigm for cancer treatment.

Selective organ targeting nanoparticles: from design to clinical translation

Targeting nanoparticle is a very promising therapeutic approach that can precisely target specific sites to treat diseases. Research on nanoscale drug delivery systems has made great progress in the past few years, making targeting nanoparticles a promising prospect. However, selective targeting nanoparticles designed for specific organs still face several challenges, one of which is the unknown fate of nanoparticles in vivo. This review starts with the in vivo journey of nanoparticles and describes the biological barriers and some targeting strategies for nanoparticles to target specific organs. Then, through the collection of literature in recent years, the design of selective targeting nanoparticles for various organs is illustrated, which provides a reference strategy for people to study the design of selective organ targeting nanoparticles. Ultimately, the prospect and challenge of selective organ targeting nanoparticles are discussed by collecting the data of clinical trials and marketed drugs.

Molecular/Nanomechanical Insights into Electrostimulation-Inhibited Energy Metabolism Mechanisms and Cytoskeleton Damage of Cancer Cells

Inhibiting energy metabolism of cancer cells is an effective way to treat cancer but remains a great challenge. Herein, electrostimulation (ES) is applied to effectively suppress energy metabolism of cancer cells to induce rapid cell death, and deeply reveal the underlying mechanisms at the molecular and nanomechanical levels by combined use of fluorescence imaging and atomic force microscopy. Cancer cells are found significantly less tolerant to ES than normal cells; and ES causes "domino effect" to induce mitochondrial dysfunction to impede electron transport chain (ETC) and tricarboxylic acid (TCA) cycle pathways, leading to fatal energy-supply crisis and death of cancer cells. From the perspective of cell mechanics, the Young's modulus decreases and cytoskeleton destruction of MCF-7 cell membranes caused by F-actin depolymerization occurs, along with down-regulation and sporadic distribution of glucose transporter 1 (GLUT1) after ES. Such a double whammy renders ES highly effective and promising for potential clinical cancer treatments.

Natural epidithiodiketopiperazine alkaloids as potential anticancer agents: Recent mechanisms of action, structural modification, and synthetic strategies

Cancer has become a grave health crisis that threatens the lives of millions of people worldwide. Because of the drawbacks of the available anticancer drugs, the development of novel and efficient anticancer agents should be encouraged. Epidithiodiketopiperazine (ETP) alkaloids with a 2,5-diketopiperazine (DKP) ring equipped with transannular disulfide or polysulfide bridges or S-methyl moieties constitute a special subclass of fungal natural products. Owing to their privileged sulfur units and intriguing architectural structures, ETP alkaloids exhibit excellent anticancer activities by regulating multiple cancer proteins/signaling pathways, including HIF-1, NF-κB, NOTCH, Wnt, and PI3K/AKT/mTOR, or by inducing cell-cycle arrest, apoptosis, and autophagy. Furthermore, a series of ETP alkaloid derivatives obtained via structural modification showed more potent anticancer activity than natural ETP alkaloids. To solve supply difficulties from natural resources, the total synthetic routes for several ETP alkaloids have been designed. In this review, we summarized several ETP alkaloids with anticancer properties with particular emphasis on their underlying mechanisms of action, structural modifications, and synthetic strategies, which will offer guidance to design and innovate potential anticancer drugs.

Fasting: From Physiology to Pathology

Overnutrition is a risk factor for various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. Therefore, targeting overnutrition represents a simple but attractive strategy for the treatment of these increasing public health threats. Fasting as a dietary intervention for combating overnutrition has been extensively studied. Fasting has been practiced for millennia, but only recently have its roles in the molecular clock, gut microbiome, and tissue homeostasis and function emerged. Fasting can slow aging in most species and protect against various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. These centuried and unfading adventures and explorations suggest that fasting has the potential to delay aging and help prevent and treat diseases while minimizing side effects caused by chronic dietary interventions. In this review, recent animal and human studies concerning the role and underlying mechanism of fasting in physiology and pathology are summarized, the therapeutic potential of fasting is highlighted, and the combination of pharmacological intervention and fasting is discussed as a new treatment regimen for human diseases.

Tumor microenvironment-regulating nanomedicine design to fight multi-drug resistant tumors

The tumor microenvironment (TME) is a very cunning system that enables tumor cells to escape death post-traditional antitumor treatments through the comprehensive effect of different factors, thereby leading to drug resistance. Deep insights into TME characteristics and tumor resistance encourage the construction of nanomedicines that can remodel the TME against drug resistance. Tremendous interest in combining TME-regulation measurement with traditional tumor treatment to fight multidrug-resistant tumors has been inspired by the increasing understanding of the role of TME reconstruction in improving the antitumor efficiency of drug-resistant tumor therapy. This review focuses on the underlying relationships between specific TME characteristics (such as hypoxia, acidity, immunity, microorganisms, and metabolism) and drug resistance in tumor treatments. The exciting antitumor activities strengthened by TME regulation are also discussed in-depth, providing solutions from the perspective of nanomedicine design. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

New target DDR1: A "double-edged sword" in solid tumors

Globally, cancer is a major catastrophic disease that seriously threatens human health. Thus, there is an urgent need to find new strategies to treat cancer. Among them, identifying new targets is one of the best ways to treat cancer at present. Especially in recent years, scientists have discovered many new targets and made breakthroughs in the treatment of cancer, bringing new hope to cancer patients. As one of the novel targets for cancer treatment, DDR1 has attracted much attention due to its unique role in cancer. Hence, here, we focus on a new target, DDR1, which may be a "double-edged sword" of human solid tumors. In this review, we provide a comprehensive overview of how DDR1 acts as a "double-edged sword" in cancer. First, we briefly introduce the structure and normal physiological function of DDR1; Second, we delineate the DDR1 expression pattern in single cells; Next, we sorte out the relationship between DDR1 and cancer, including the abnormal expression of DDR1 in cancer, the mechanism of DDR1 and cancer occurrence, and the value of DDR1 on cancer prognosis. In addition, we introduced the current status of global drug and antibody research and development targeting DDR1 and its future design prospects; Finally, we summarize and look forward to designing more DDR1-targeting drugs in the future to make further progress in the treatment of solid tumors.

Enhanced Sensitivity of Tumor Cells to Autophagy Inhibitors Using Fasting-Mimicking Diet and Targeted Lysosomal Delivery Nanoplatform

Autophagy is one of the key pathways for tumor cell survival and proliferation. Therefore, inhibition of autophagy has been extensively studied for cancer therapy. However, current autophagy inhibitors lack specificity and are ineffective in limiting tumor progression. Herein, we report a nanoplatform for tumor-site-targeted delivery of hydroxychloroquine (HCQ) using insulin-like growth factors 2 receptor (IGF2R)-targeted liposomes (iLipo-H). A fasting-mimicking diet (FMD) is used to increase the autophagy levels in tumor cells, thereby increasing the sensitivity of tumor cells to HCQ. In addition, FMD treatment upregulates the expression of IGF2R in tumor cells, but not normal cells. Consequently, iLipo-H nanoparticles efficiently accumulate at the tumor site under FMD condition. In vivo studies demonstrate that iLipo-H nanoparticles efficiently inhibit 4T1 tumor growth without obvious side effects, especially under FMD condition. This study provides a promising strategy to increase the sensitivity of tumor cells to autophagy inhibitors for effective cancer therapy.

Regulation of Nucleotide Metabolism with Nutrient-Sensing Nanodrugs for Cancer Therapy

The continual growth of tumor cells requires considerable nutrient consumption. Methotrexate (MTX) is used to treat certain types of cancer by blocking the DNA and RNA productions through interfering one-carbon metabolism and de novo purine and pyrimidine synthesis. However, treatment of MTX may cause many serious adverse effects, which hamper its clinical application. Herein, the authors synthesize ferrous ions, histidine, and MTX assembled nanoparticles (FHM) to deliver MTX at tumor site and enhance the sensitivity of tumor cells to MTX with histidine catabolism. Furthermore, fasting-mimicking diet (FMD) is applied to intervene in the one-carbon metabolism and enhance the cytotoxicity of MTX. Meanwhile, FMD treatment can significantly augment the cellular uptake and tumor accumulation of FHM nanoparticles. Due to the triple inhibitions of the one-carbon metabolism, the proliferation of tumor cells is strongly disturbed, as which is highly replying on DNA and RNA production. Taken together, a 95% lower dose of MTX adopted in combined therapy significantly inhibits the growth of two types of murine tumors without evident systemic toxicity. This strategy may provide a promising nucleotide metabolism-based nanomedicine for cancer therapy.