Extracellular vesicle-packaged HIF-1α-stabilizing lncRNA from tumour-associated macrophages regulates aerobic glycolysis of breast cancer cells

Hypoxia inducible factor-1 signaling pathway in macrophage involved angiogenesis in materials-instructed osteo-induction

Although osteo-inductive materials are regarded as promising candidates for critical-sized bone repair, their clinical application is limited by ambiguous mechanisms. The hypoxia-inducible factor (HIF)-1 signaling pathway, which responds to hypoxic conditions, is involved in both angiogenesis and osteogenesis. Strategies harnessing HIF-1 signaling to promote angiogenesis have been applied and have succeeded in repairing segmental bone defects. Meanwhile, macrophages have been shown to have important immunoregulatory effects on material-induced osteo-induction and correlate with HIF-1 activity. Thus, it is reasonable to assume that HIF-activated macrophages may also play important roles in the angiogenesis of material-induced osteo-induction. To verify this assumption, a classical type of osteo-inductive calcium phosphate (TCPs) was utilized. First, using RNA sequencing, we found that hypoxia activated the HIF signaling pathway in macrophages, which contributed to angiogenesis in TCPs. In addition, after treatment with a conditioned medium extracted from the co-culture system of macrophages and TCPs under hypoxic conditions, the migration and tube formation ability of human umbilical vein endothelial cells (HUVECs) significantly increased. In vivo, inhibition of HIF-1 or clearance of macrophages could result in impaired angiogenesis in TCPs. Finally, more blood vessels were formed in the TCPs group than in the control group. In conclusion, this study elucidated the vital role of the HIF signaling pathway in infiltrating macrophages during early vessel growth in material-induced osteo-induction. It is beneficial in advancing the exploration of the related mechanism and providing possible support for optimizing the applicability of osteo-inductive materials in bone repair.

Cellular reprogramming, chemoresistance, and dietary interventions in breast cancer

Breast cancer (BC) diagnosis has been associated with significant risk factors, including family history, late menopause, obesity, poor eating habits, and alcoholism. Despite the advances in the last decades regarding cancer treatment, some obstacles still hinder the effectiveness of therapy. For example, chemotherapy resistance is common in locally advanced or metastatic cancer, reducing treatment options and contributing to mortality. In this review, we provide an overview of BC metabolic changes, including the impact of restrictive diets associated with chemoresistance, the therapeutic potential of the diet on tumor progression, pathways related to metabolic health in oncology, and perspectives on the future in the area of oncological nutrition.

Long noncoding RNA HOXC-AS3 interacts with CDK2 to promote proliferation in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a type of cancer that affects the liver and has a high mortality rate. Long non-coding RNAs (lncRNAs) dysregulation can contribute to cancer occurrence and progression, although the underlying molecular pathways are mostly unclear. HOXC-AS3 was found to be considerably overexpressed in HCC in this investigation. The goal of this work was to look into the involvement of HOXC-AS3 in HCC and the various molecular pathways that underpin it.

Methods

Normal liver and paired HCC tissues from HCC patients were used to evaluate HOXC-AS3 expression by qRT-PCR. The role of HOXC-AS3 in HCC was assessed both in vitro and in vivo. RNA pulldown, RIP and co-IP were used to demonstrate the potential mechanism by which HOXC-AS3 regulates the progression of HCC.

Results

Using qRT-PCR, it was discovered that HOXC-AS3 was substantially expressed in HCC. In vitro and in vivo, overexpression of HOXC-AS3 aided proliferation and cell cycle progression. HOXC-AS3 interacted with CDK2 to facilitate CDK2’s decreased binding to p21, resulting in enhanced CDK2 activity, which promoted the phosphorylation of Rb and the progression of HCC.

Conclusions

HOXC-AS3 is highly expressed in HCC and can promote the progression of HCC by interacting with CDK2. Therefore, targeting HOXC-AS3 is very likely to provide a new strategy for the treatment of HCC and for improving patient prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-022-00411-2.

Purinergic receptors are a key bottleneck in tumor metabolic reprogramming: The prime suspect in cancer therapeutic resistance

ATP and other nucleoside phosphates have specific receptors named purinergic receptors. Purinergic receptors and ectonucleotidases regulate various signaling pathways that play a role in physiological and pathological processes. Extracellular ATP in the tumor microenvironment (TME) has a higher level than in normal tissues and plays a role in cancer cell growth, survival, angiogenesis, metastasis, and drug resistance. In this review, we investigated the role of purinergic receptors in the development of resistance to therapy through changes in tumor cell metabolism. When a cell transforms to neoplasia, its metabolic processes change. The metabolic reprogramming modified metabolic feature of the TME, that can cause impeding immune surveillance and promote cancer growth. The purinergic receptors contribute to therapy resistance by modifying cancer cells' glucose, lipid, and amino acid metabolism. Limiting the energy supply of cancer cells is one approach to overcoming resistance. Glycolysis inhibitors which reduce intracellular ATP levels may make cancer cells more susceptible to anti-cancer therapies. The loss of the P2X7R through glucose intolerance and decreased fatty acid metabolism reduces therapeutic resistance. Potential metabolic blockers that can be employed in combination with other therapies will aid in the discovery of new anti-cancer immunotherapy to overcome therapy resistance. Therefore, therapeutic interventions that are considered to inhibit cancer cell metabolism and purinergic receptors simultaneously can potentially reduce resistance to treatment.

Long non-coding RNAs play an important regulatory role in tumorigenesis and tumor progression through aerobic glycolysis

Compared to normal cells, cancer cells generate ATP mainly through aerobic glycolysis, which promotes tumorigenesis and tumor progression. Long non-coding RNAs (LncRNAs) are a class of transcripts longer than 200 nucleotides with little or without evident protein-encoding function. LncRNAs are involved in the ten hallmarks of cancer, interestingly, they are also closely associated with aerobic glycolysis. However, the mechanism of this process is non-transparent to date. Demonstrating the mechanism of lncRNAs regulating tumorigenesis and tumor progression through aerobic glycolysis is particularly critical for cancer therapy, and may provide novel therapeutic targets or strategies in cancer treatment. In this review, we discuss the role of lncRNAs and aerobic glycolysis in tumorigenesis and tumor progression, and further explore their interaction, in hope to provide a novel therapeutic target for cancer treatment.

Tumour Derived Extracellular Vesicles: Challenging Target to Blunt Tumour Immune Evasion

Simple Summary

Tumour onset and development occur because of specific immune support. The immune system, which is originally able to perceive and eliminate incipient cancer cells, becomes suppressed and hijacked by cancer. For these purposes, tumour cells use extracellular vesicles (TEVs). Specific molecular composition allows TEVs to reprogram immune cells towards tumour tolerance. Circulating TEVs move from their site of origin to other organs, preparing “a fertile soil” for metastasis formation. This implies that TEV molecular content can provide a valuable tool for cancer biomarker discovery and potential targets to reshape the immune system into tumour recognition and eradication.

Abstract

Control of the immune response is crucial for tumour onset and progression. Tumour cells handle the immune reaction by means of secreted factors and extracellular vesicles (EV). Tumour-derived extracellular vesicles (TEV) play key roles in immune reprogramming by delivering their cargo to different immune cells. Tumour-surrounding tissues also contribute to tumour immune editing and evasion, tumour progression, and drug resistance via locally released TEV. Moreover, the increase in circulating TEV has suggested their underpinning role in tumour dissemination. This review brings together data referring to TEV-driven immune regulation and antitumour immune suppression. Attention was also dedicated to TEV-mediated drug resistance.

Tumor-associated macrophage (TAM)-derived CCL22 induces FAK addiction in esophageal squamous cell carcinoma (ESCC)

Tumor cell dependence on activated oncogenes is considered a therapeutic target, but protumorigenic microenvironment-mediated cellular addiction to specific oncogenic signaling molecules remains to be further defined. Here, we showed that tumor-associated macrophages (TAMs) produced an abundance of C-C motif chemokine 22 (CCL22), whose expression in the tumor stroma was positively associated with the level of intratumoral phospho-focal adhesion kinase (pFAK Tyr³⁹⁷), tumor metastasis and reduced patient survival. Functionally, CCL22-stimulated hyperactivation of FAK was correlated with increased malignant progression of cancer cells. CCL22-induced addiction to FAK was demonstrated by the persistent suppression of tumor progression upon FAK-specific inhibition. Mechanistically, we identified that diacylglycerol kinase α (DGKα) acted as a signaling adaptor to link the CCL22 receptor C-C motif chemokine receptor 4 (CCR4) and FAK and promoted CCL22-induced activation of the FAK/AKT pathway. CCL22/CCR4 signaling activated the intracellular Ca²⁺/phospholipase C-γ1 (PLC-γ1) axis to stimulate the phosphorylation of DGKα at a tyrosine residue (Tyr³³⁵) and promoted the translocation of DGKα to the plasma membrane to assemble the DGKα/FAK signalosome, which critically contributed to regulating sensitivity to FAK inhibitors in cancer cells. The identification of TAM-driven intratumoral FAK addiction provides opportunities for utilizing the tumor-promoting microenvironment to achieve striking anticancer effects.

Exosomal circular RNAs: Biogenesis, effect, and application in cardiovascular diseases

As natural nanoparticles, exosomes regulate a wide range of biological processes via modulation of its components, including circular RNAs (circRNAs). CircRNAs are a novel class of closed-loop single-stranded RNAs with a wide distribution, and play diverse biological roles. Due to its stability in exosomes, exosomal circRNAs serve as biomarkers, pathogenic regulators and exert therapeutic potentials in some cardiovascular diseases, including atherosclerosis, acute coronary syndrome, ischemia/reperfusion injury, heart failure, and peripheral artery disease. In this review, we detailed the current knowledge on the biogenesis and functions of exosomes, circRNAs, and exosomal circRNAs, as well as their involvement in these cardiovascular diseases, providing novel insights into the diagnosis and treatment of these diseases.

Mechanism research and treatment progress of NAD pathway related molecules in tumor immune microenvironment

Nicotinamide adenine dinucleotide (NAD) is the core of cellular energy metabolism. NAMPT, Sirtuins, PARP, CD38, and other molecules in this classic metabolic pathway affect many key cellular functions and are closely related to the occurrence and development of many diseases. In recent years, several studies have found that these molecules can regulate cell energy metabolism, promote the release of related cytokines, induce the expression of neoantigens, change the tumor immune microenvironment (TIME), and then play an anticancer role. Drugs targeting these molecules are under development or approved for clinical use. Although there are some side effects and drug resistance, the discovery of novel drugs, the development of combination therapies, and the application of new technologies provide solutions to these challenges and improve efficacy. This review presents the mechanisms of action of NAD  pathway-related molecules in tumor immunity, advances in drug research, combination therapies, and some new technology-related therapies.

Lactate promotes metastasis of normoxic colorectal cancer stem cells through PGC-1α-mediated oxidative phosphorylation

Uneven oxygen supply in solid tumors leads to hypoxic and normoxic regions. Hypoxic cells exhibit increased secretion of lactate, which creates an acidic tumor microenvironment (TME). This acidic TME is positively associated with tumor metastasis. Despite the increased metastatic capacity of hypoxic cells, they are located relatively further away from the blood vessels and have limited access to the circulatory system. Studies have shown that cancer stem cells (CSCs) are enriched for tumor metastasis-initiating cells and generally undergo aerobic respiration, which could be enhanced by lactate. We therefore hypothesized that TME-derived lactate may promote the metastasis of normoxic CSCs. In the present study, the abundance of hypoxic and normoxic CSCs was analyzed in primary CRC tumors. It was found that the proportion of normoxic CSCs was positively associated with tumor stage. Using two human CRC cell lines, LoVo and SW480, and a patient-derived xenograft (XhCRC), it was found that treatment with lactate promoted normoxic CSC metastasis. Metabolism analysis indicated that, upon treatment with lactate, oxidative phosphorylation (OXPHOS) activity in normoxic CSCs was enhanced, whereas hypoxic CSCs were rarely altered. At the molecular level, the expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a master regulator of lactate oxidation, was found to be elevated in normoxic CSCs. Furthermore, PGC-1α knockdown markedly reduced the metastatic potential of normoxic CSCs. Notably, both the PGC-1α-mediated OXPHOS activity and metastatic potential were impaired when hypoxia-inducible factor-1α (HIF-1α) was activated in normoxic CSCs. Together, these findings provide a therapeutic strategy against tumor metastasis through the targeting of PGC-1α and, thus, the suppression of lactate-feeding OXPHOS in normoxic CSCs may improve the therapeutic benefit of patients with cancer, particularly CRC.

Noncoding RNAs as sensors of tumor microenvironmental stress

The tumor microenvironment (TME) has been demonstrated to modulate the biological behavior of tumors intensively. Multiple stress conditions are widely observed in the TME of many cancer types, such as hypoxia, inflammation, and nutrient deprivation. Recently, accumulating evidence demonstrates that the expression levels of noncoding RNAs (ncRNAs) are dramatically altered by TME stress, and the dysregulated ncRNAs can in turn regulate tumor cell proliferation, metastasis, and drug resistance. In this review, we elaborate on the signal transduction pathways or epigenetic pathways by which hypoxia-inducible factors (HIFs), inflammatory factors, and nutrient deprivation in TME regulate ncRNAs, and highlight the pivotal roles of TME stress-related ncRNAs in tumors. This helps to clarify the molecular regulatory networks between TME and ncRNAs, which may provide potential targets for cancer therapy.

Long non-coding RNA ANRIL promotes chemoresistance in triple-negative breast cancer via enhancing aerobic glycolysis

AIMS

lncRNA ANRIL expression is dysregulated in many human cancers and is thus a useful prognostic marker for cancer patients. However, whether ANRIL is involved in drug resistance in triple-negative breast cancer (TNBC) has not yet been investigated.

MAIN METHODS

A luciferase reporter assay was conducted to verify the binding between miR-125a and ANRIL. RT-PCR and western blotting were performed to detect the expression of miR-125a, ANRIL, and ENO1. Glycolysis stress was assessed using the Seahorse extracellular flux analyzer. Functional studies were performed using both in vitro and in vivo xenograft models.

KEY FINDINGS

ANRIL was markedly upregulated in both patients with TNBC and TNBC cell lines. Knockdown of ANRIL increased the cytotoxic effect of ADR and repressed cellular glycolytic activity in TNBC cells. Mechanistic analysis showed that ANRIL may act as a competing endogenous RNA of miR-125a to relieve the repressive effect of miR-125a on its target glycolytic enzyme enolase (ENO1). Notably, 2-deoxy-glucose attenuated ANRIL-induced increase in drug resistance in TNBC cells.

SIGNIFICANCE

These results indicate that knockdown of ANRIL plays an active role in overcoming drug resistance in TNBC by inhibiting glycolysis through the miR-125a/ENO1 pathway, which may be useful for the development of novel therapeutic targets for treating patients with TNBC, especially those with drug resistance.

Effects of Metabolism on Macrophage Polarization Under Different Disease Backgrounds

Macrophages are versatile immune cells associated with various diseases, and their phenotypes and functions change on the basis of the surrounding environments. Reprogramming of metabolism is required for the proper polarization of macrophages. This review will focus on basic metabolic pathways, the effects of key enzymes and specific products, relationships between cellular metabolism and macrophage polarization in different diseases and the potential prospect of therapy targeted key metabolic enzymes. In particular, the types and characteristics of macrophages at the maternal-fetal interface and their effects on a successful conception will be discussed.

CNN1 Represses Bladder Cancer Progression and Metabolic Reprogramming by Modulating HIF-1α Signaling Pathway

Bladder cancer (BC) is the second most common urinary system malignant tumor around the whole world. It has been reported that CNN1 was lowly expressed in BC tissues. However, the mechanisms of CNN1 on BC cells were unclear. Herein, we aimed to probe the specific influences of CNN1 on BC pathogenesis. First, the expression level and prognostic ability of CNN1 in BC patients were surveyed. Then, CNN1 overexpression was executed to exhibit the influences of CNN1 on BC cells. The real-time PCR and Western blotting were employed to detect by the mRNA and protein expression levels. CCK8 assay was utilized to examine cell proliferation, and transwell assay was executed to test cell invasion and migration. The corresponding kits were utilized to detect glucose absorption, lactate secretion, and ATP level. BC cells overexpressing CNN1 were utilized to establish a nude mouse xenograft tumor model, and the tumor volume and tumor weight were detected. Nude mouse tumor tissues were used for immunohistochemical experiments to test the expression levels of Ki-67 and CNN1. The outcomes indicated that CNN1 was significantly lowly expressed in BC tissues and cells. Besides, low expression of CNN1 might be concerned with poor prognosis. Moreover, overexpression of CNN1 repressed the proliferation, invasion, and migration of BC cells. Furthermore, CNN1 overexpression decreased the protein levels of glycolysis-related protein GLUT1 (glucose transporter 1), pyruvate kinase M2 (PKM2), and LDHA (lactate dehydrogenase A). Then, the decreased mRNA and protein levels of HIF-1α and PDK1 were identified after CNN1 overexpression. The in vivo assays verified the effects of aberrant expression of CNN1 in mice with BC. In conclusion, these findings suggested that CNN1 might modulate BC progression through activating HIF-1α pathway and CNN1 might be a promising marker for BC diagnosis.

Cuproptosis-Related Risk Score Predicts Prognosis and Characterizes the Tumor Microenvironment in Hepatocellular Carcinoma

Aims

Cuproptosis is a recently identified form of programmed cell death; however, its role in hepatocellular carcinoma (HCC) remains unclear.

Methods

A set of bioinformatic tools was integrated to analyze the expression and prognostic significance of ferredoxin 1 (FDX1), the key regulator of cuproptosis. A cuproptosis-related risk score (CRRS) was developed via correlation analyses, least absolute shrinkage and selection operator (LASSO) Cox regression, and multivariate Cox regression. The metabolic features, mutation signatures, and immune profile of CRRS-classified HCC patients were investigated, and the role of CRRS in therapy guidance was analyzed.

Results

FDX1 was significantly downregulated in HCC, and its high expression was associated with longer survival time. HCC patients in the high-CRRS group showed a significantly lower overall survival (OS) and enriched in cancer-related pathways. Mutation analyses revealed that the high-CRRS HCC patients had a high mutational frequency of some tumor suppressors such as tumor protein P53 (TP53) and Breast-cancer susceptibility gene 1 (BRCA1)-associated protein 1 (BAP1) and a low frequency of catenin beta 1 (CTNNB1). Besides, HCC patients with high CRRS showed an increase of protumor immune infiltrates and a high expression of immune checkpoints. Moreover, the area under the curve (AUC) values of CRRS in predicting the efficiency of sorafenib and the non-responsiveness to transcatheter arterial chemoembolization (TACE) in HCC patients reached 0.877 and 0.764, respectively.

Significance

The cuproptosis-related signature is helpful in prognostic prediction and in guiding treatment for HCC patients.

Metabolic Reprogramming Induces Macrophage Polarization in the Tumor Microenvironment

Macrophages are one of the most important cells in the innate immune system, they are converted into two distinct subtypes with completely different molecular phenotypes and functional features under different stimuli of the microenvironment: M1 macrophages induced by IFN-γ/lipopolysaccharides(LPS) and M2 macrophages induced by IL-4/IL-10/IL-13. Tumor-associated macrophages (TAMs) differentiate from macrophages through various factors in the tumor microenvironment (TME). TAMs have the phenotype and function of M2 macrophages and are capable of secreting multiple cytokines to promote tumor progression. Both tumor cells and macrophages can meet the energy needs for rapid cell growth and proliferation through metabolic reprogramming, so a comprehensive understanding of pro-tumor and antitumor metabolic switches in TAM is essential to understanding immune escape mechanisms. This paper focuses on the functions of relevant signaling pathways and cytokines during macrophage polarization and metabolic reprogramming, and briefly discusses the effects of different microenvironments and macrophage pathogenicity, in addition to describing the research progress of inhibitory drugs for certain metabolic and polarized signaling pathways.

Adipose-Derived Mesenchymal Stem Cells Reprogram M1 Macrophage Metabolism via PHD2/HIF-1α Pathway in Colitis Mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease worldwide. Infiltration of pro-inflammatory macrophages (M1 macrophages) contributes to the occurrence of bowel inflammation. Transplantation of mesenchymal stem cells (MSCs) is a promising therapeutic strategy for UC, but the exact mechanism remains unknow yet. Here, we treated DSS-induced colitis mice with adipose‐derived mesenchymal stem cells (ADMSCs) and revealed that ADMSCs alleviated colon inflammation by reducing the infiltration of M1 macrophages. Moreover, ADMSCs exerted this therapeutic effect by inhibiting succinate accumulation, increasing PHD2 to prevent M1 macrophages from overexpressing HIF-1α and thereby reprogramming the glycolytic pathway of M1 macrophages. Meanwhile, the succinate secreted by M1 macrophages triggered ADMSCs to secrete PGE2 in return, which could also shift macrophages from M1 phenotype to M2. Our work demonstrated an immunomodulatory effect of ADMSCs and provided a novel perspective on UC therapy.

LncRNA-mRNA Expression Profiles of Osteoclast After Conditional Knockout HIF-1α

Background: Osteoclasts, which are multinucleated cells formed by monocyte fusion, play a key role in bone resorption. Hypoxia-inducible factor (HIF)-1α is vital for the development of osteoclasts in hypoxic environments and during bone resorption. However, additional research is required to further study the HIF-1α-dependent regulation of osteoclast differentiation at the genetic level.

Methods: In our study, RNA sequencing (RNA-seq) was used to identify the expression profiles of long noncoding RNAs (lncRNAs) and mRNAs in conditional HIF-1α-knockout osteoclasts.

Results: A total of 1,320 mRNAs and 95 lncRNAs were differentially expressed. The expression of lncRNAs MSTRG.7566.12 and MSTRG.31769.2 were strongly negatively correlated with that of Mmp9, Ctsk, etc.

Conclusion: Our research provides a basis for further understanding the role of mRNAs and lncRNAs in conditional HIF-1α-knockout osteoclasts, and many of these molecules may be potential targets for treating bone diseases related to HIF-1α.

LncRNAs in tumor metabolic reprogramming and immune microenvironment remodeling

Evidence accumulated over the past decade has verified that long non-coding RNAs (lncRNAs) exert important functions in multiple cell programs. As a novel class of cellular regulatory molecules, lncRNAs interact with different molecules, such as DNA, RNA or proteins, depending on their subcellular distribution, to modulate gene transcription and kinase cascades. It has been widely clarified that lncRNAs play important roles in modulating metabolic reprogramming and reshaping the immune landscape and serve as hinges bridging tumor metabolism and anti-tumor immunity. Given these facts, lncRNAs, as putative regulators of tumor initiation and progression, have attracted extensive attention in recent years. In this review, we summarized the current research progress on the role of lncRNAs in tumor metabolic reprogramming and tumor-immune microenvironment remodeling, and conclude with our laboratory's contributions in advancing the clinical applications of lncRNAs.

The effect of HIF on metabolism and immunity

Cellular hypoxia occurs when the demand for sufficient molecular oxygen needed to produce the levels of ATP required to perform physiological functions exceeds the vascular supply, thereby leading to a state of oxygen depletion with the associated risk of bioenergetic crisis. To protect against the threat of hypoxia, eukaryotic cells have evolved the capacity to elicit oxygen-sensitive adaptive transcriptional responses driven primarily (although not exclusively) by the hypoxia-inducible factor (HIF) pathway. In addition to the canonical regulation of HIF by oxygen-dependent hydroxylases, multiple other input signals, including gasotransmitters, non-coding RNAs, histone modifiers and post-translational modifications, modulate the nature of the HIF response in discreet cell types and contexts. Activation of HIF induces various effector pathways that mitigate the effects of hypoxia, including metabolic reprogramming and the production of erythropoietin. Drugs that target the HIF pathway to induce erythropoietin production are now approved for the treatment of chronic kidney disease-related anaemia. However, HIF-dependent changes in cell metabolism also have profound implications for functional responses in innate and adaptive immune cells, and thereby heavily influence immunity and the inflammatory response. Preclinical studies indicate a potential use of HIF therapeutics to treat inflammatory diseases, such as inflammatory bowel disease. Understanding the links between HIF, cellular metabolism and immunity is key to unlocking the full therapeutic potential of drugs that target the HIF pathway.

Hypoxia-dependent changes in cellular metabolism have important implications for the effective functioning of multiple immune cell subtypes. This Review describes the inputs that shape the hypoxic response in individual cell types and contexts, and the implications of this response for cellular metabolism and associated alterations in immune cell function.

Hypoxia is a common feature of particular microenvironments and at sites of immunity and inflammation, resulting in increased activity of the hypoxia-inducible factor (HIF).

In addition to hypoxia, multiple inputs modulate the activity of the HIF pathway, allowing nuanced downstream responses in discreet cell types and contexts.

HIF-dependent changes in cellular metabolism mitigate the effects of hypoxia and ensure that energy needs are met under conditions in which oxidative phosphorylation is reduced.

HIF-dependent changes in metabolism also profoundly affect the phenotype and function of immune cells.

The immunometabolic effects of HIF have important implications for targeting the HIF pathway in inflammatory disease.

The multifaceted role of EGLN family prolyl hydroxylases in cancer: going beyond HIF regulation

EGLN1, EGLN2 and EGLN3 are proline hydroxylase whose main function is the regulation of the HIF factors. They work as oxygen sensors and are the main responsible of HIFα subunits degradation in normoxia. Being their activity strictly oxygen-dependent, when oxygen tension lowers, their control on HIFα is released, leading to activation of systemic and cellular response to hypoxia. However, EGLN family members activity is not limited to HIF modulation, but it includes the regulation of essential mechanisms for cell survival, cell cycle metabolism, proliferation and transcription. This is due to their reported hydroxylase activity on a number of non-HIF targets and sometimes to hydroxylase-independent functions. For these reasons, EGLN enzymes appear fundamental for development and progression of different cancer types, playing either a tumor-suppressive or a tumor-promoting role, according to EGLN isoform and to tumor context. Notably, EGLN1, the most studied isoform, has been shown to have also a central role in tumor micro-environment modulation, mediating CAF activation and impairing HIF1α -related angiogenesis, thus covering an important function in cancer metastasis promotion. Considering the recent knowledge acquired on EGLNs, the possibility to target these enzymes for cancer treatment is emerging. However, due to their multifaceted and controversial roles in different cancer types, the use of EGLN inhibitors as anti-cancer drugs should be carefully evaluated in each context.

New Sights Into Long Non-Coding RNA LINC01133 in Cancer

LINC01133 is a long intergenic non-coding RNA that regulates malignancy in several cancers, including those of the digestive, female reproductive, respiratory, and urinary system. LINC01133 is an extensively studied lncRNA that is highly conserved, and its relatively stable expression is essential for its robust biological function. Its expression is highly tissue-specific with a distinct subcellular localization. It functions as an oncogene or a tumor suppressor gene in different cancers via multiple mechanisms, such as those that involve competing with endogenous RNA and binding to RNA-binding proteins or DNA. Moreover, the secretion and transportation of LINC01133 by extracellular vesicles in the tumor micro-environment is regulated by other cells in the tumor micro-environment. To date, two mechanisms, an increase in copy number and regulation of transcription elements, have been found to regulate LINC01133 expression. Clinically, LINC01133 is an ideal marker for cancer prognosis and a potential therapeutic target in cancer treatment regimes. In this review, we aimed to summarize the aforementioned information as well as posit future directions for LINC01133 research.

Hypoxia-induced HIF-1α/lncRNA-PMAN inhibits ferroptosis by promoting the cytoplasmic translocation of ELAVL1 in peritoneal dissemination from gastric cancer

Peritoneal metastasis (PM) is the main site of gastric cancer (GC) distant metastasis and indicates an extremely poor prognosis and survival. Hypoxia is a common feature of peritoneal metastases and up-regulation of hypoxia inducible factor 1 alpha (HIF-1α) may be a potential driver in the occurrence of PM. Ferroptosis is a recently discovered form of regulated cell death and closely related to the occurrence and development of tumors. However, the underlying mechanism link HIF-1α to ferroptosis in PM of GC remains unknown. Here, lncRNA-microarrays and RNA library construction/lncRNA-seq results shown that lncRNA-PMAN was highly expressed in PM and significantly modulated by HIF-1α. Upregulation of PMAN is associated with poor prognosis and PM in patients with GC. PMAN was up-regulated by HIF-1α and improved the stability of SLC7A11 mRNA by promoting the cytoplasmic distribution of ELAVL1, which was identified in RNA-pulldown/mass spectrometry results. Accumulation of SLC7A11 increases the level of l-Glutathione (GSH) and inhibits the accumulation of reactive oxygen species (ROS) and irons in the GC cells. Finally protect GC cells against ferroptosis induced by Erastin and RSL3. Our findings have elucidated the effect of HIF-1α/PMAN/ELAVL1 in GC cells ferroptosis and provides theoretical support for the potential diagnostic biomarkers and therapeutic targets for PM in GC.

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HIF-1⍺ mediates abnormally high expression of PMAN in PM from GC under hypoxia.

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GC cells suppress ferroptosis by relieving ROS and irons accumulation through HIF-1⍺/PMAN under hypoxia.

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Inhibition of ferroptosis may contributes to the development of PM from GC.

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Increased cytoplasmic translocation of ELAVL1 is a key intermediate factor in PMAN inhibition of ferroptosis.

The theory of tumor ecosystem

Cancer cells can be conceived as “living organisms” interacting with cellular or non‐cellular components in the host internal environment, not only the local tumor microenvironment but also the distant organ niches, as well as the immune, nervous and endocrine systems, to construct a self‐sustainable tumor ecosystem. With increasing evidence for the systemic tumor‐host interplay, we predict that a new era of cancer therapy targeting the ecosystemic vulnerability of human malignancies has come. Revolving around the tumor ecosystem scoped as different hierarchies of primary, regional, distal and systemic onco‐spheres, we comprehensively review the tumor‐host interaction among cancer cells and their local microenvironment, distant organ niches, immune, nervous and endocrine systems, highlighting material and energy flow with tumor ecological homeostasis as an internal driving force. We also substantiate the knowledge of visualizing, modelling and subtyping this dynamically intertwined network with recent technological advances, and discuss ecologically rational strategies for more effective cancer therapies.

Modulating tumor physical microenvironment for fueling CAR-T cell therapy

Chimeric antigen receptor (CAR) T cell therapy has achieved unprecedented clinical success against hematologic malignancies. However, the transition of CAR-T cell therapies for solid tumors is limited by heterogenous antigen expression, immunosuppressive microenvironment (TME), immune adaptation of tumor cells and impeded CAR-T-cell infiltration/transportation. Recent studies increasingly reveal that tumor physical microenvironment could affect various aspects of tumor biology and impose profound impacts on the antitumor efficacy of CAR-T therapy. In this review, we discuss the critical roles of four physical cues in solid tumors for regulating the immune responses of CAR-T cells, which include solid stress, interstitial fluid pressure, stiffness and microarchitecture. We highlight new strategies exploiting these features to enhance the therapeutic potency of CAR-T cells in solid tumors by correlating with the state-of-the-art technologies in this field. A perspective on the future directions for developing new CAR-T therapies for solid tumor treatment is also provided.

A brain-enriched lncRNA shields cancer cells from immune-mediated killing for metastatic colonization in the brain

SignificanceBrain metastasis with current limited treatment options is a common complication in advanced cancer patients, and breast-to-brain metastasis (B2BM) is one of the major types. In this work, we report that brain metastasis oncogenic long noncoding RNA (BMOR) is a key brain-enriched long noncoding RNA for the development of B2BM. We demonstrate that BMOR allows B2BM cells to colonize the brain tissue by evading immune-mediated killing in the brain microenvironment. At the molecular level, BMOR binds and inactivates IRF3 in B2BM cells. Finally, BMOR silencer can effectively suppress the development of brain metastasis in vivo. Therefore, our findings reveal a way in which cancer cells evade immune-mediated killing in the brain microenvironment for brain metastasis development and establish therapeutic targets with potential targeted strategies against B2BM.

The Role of Hypoxia-Associated Long Non-Coding RNAs in Breast Cancer

Breast cancer is the leading cause of cancer-related deaths in women worldwide. In the United States, even with earlier diagnosis and treatment improvements, the decline in mortality has stagnated in recent years. More research is needed to provide better diagnostic, prognostic, and therapeutic tools for these patients. Long non-coding RNAs are newly described molecules that have extensive roles in breast cancer. Emerging reports have shown that there is a strong link between these RNAs and the hypoxic response of breast cancer cells, which may be an important factor for enhanced tumoral progression. In this review, we summarize the role of hypoxia-associated lncRNAs in the classic cancer hallmarks, describing their effects on the upstream and downstream hypoxia signaling pathway and the use of them as diagnostic and prognostic tools.

Dual Closed-Loop of Catalyzed Lactate Depletion and Immune Response to Potentiate Photothermal Immunotherapy

Lactate accumulation in the solid tumor is highly relevant to the immunosuppressive tumor microenvironment (TME). Targeting lactate metabolism significantly enhances the efficacy of immunotherapy. However, lactate depletion by lactate oxidase (LOX) consumes oxygen and results in the aggravated hypoxia situation, counteracting the benefit of lactate depletion. Beyond the TME regulation, it is necessary to initiate the effective immunity cycle for therapeutic purposes. In this fashion, dual close-loop of catalyzed lactate depletion and immune response by a rational material design are established to address this issue. Here, we constructed PEG-modified mesoporous polydopamine nanoparticles with Cu2+ chelation and LOX encapsulation (denoted as mCuLP). After mCuLP nanosystems targeting into the tumor sites, released LOX consumes lactate to H2O2. Subsequently, the produced H2O2 is further catalyzed by Cu2+-chelated mPDA to produce oxygen, supplying the oxygen source for the closed-loop of lactate depletion. Meanwhile, the mild PTT caused by the photothermal mPDA induces ICD of tumor cells to promote DC maturation and then T lymphocyte infiltration to kill tumor cells, which forms another closed-loop for cancer immunity. Therefore, this dual closed-loop strategy of mCuLP nanosystems effectively inhibits tumor growth, providing a promising treatment modality to cancer immunotherapy.

Identification of a novel lipid metabolism-related gene signature within the tumour immune microenvironment for breast cancer

Background

Systemic factors can strongly affect how tumour cells behave, grow, and communicate with other cells in breast cancer. Lipid metabolic reprogramming is a systemic process that tumour cells undergo; however, the formation and dynamics of lipids associated with the tumour immune microenvironment (TIME) remain unclear. The investigation of the sophisticated bidirectional crosstalk of tumour cells with cancer metabolism, gene expression, and TIME could have the potential to identify novel biomarkers for diagnosis, prognosis, and immunotherapy. This study aimed to construct a prognostic signature to detect the bicrosstalk between the lipid metabolic system and the TIME of breast cancer.

Methods

To detect the expression of LRGs and execute GO/KEGG analysis, the R program was chosen. Considering the clinical information and pathological features, a prognostic gene signature was constructed by LASSO Cox regression analysis. TMB, MSI, and immune infiltration analyses were performed, and consensus cluster analysis of LRGs was also performed.

Results

These 16 lipid metabolism-related genes (LRGs) were mainly involved in the process of lipid metabolism and fatty acid binding in breast cancer. Prognosis analysis identified the prognostic value of FABP7(Fatty acid binding protein 7) and NDUFAB1(NADH:ubiquinone oxidoreductase subunit AB1) in breast cancer patients. The prognostic gene signature constructed with FABP7 and NDUFAB1 was significantly related to immune cell infiltration and could predict the overall survival rate with above average correctness of breast cancer patients. FABP7 and NDUFAB1 were proven to have relevance in immune cell infiltration and tumour mutation burden (TMB). Consensus cluster analysis identified that the upregulated mRNAs were mostly related to the oncogenesis process, while the downregulated mRNAs were associated with immune-related signalling pathways.

Conclusion

A comprehensive analysis was performed to evaluate the lipid metabolic system and identified a signature constructed by two prognostic genes for immunotherapies in breast cancer. The results also revealed evidence of vulnerabilities in the interplay between the lipid metabolic system and the TIME in breast cancer. Further data with clinical studies and experiments are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01651-9.

Immune cells-derived exosomes function as a double-edged sword: role in disease progression and their therapeutic applications

Exosomes, ranging in size from 30 to 150 nm as identified initially via electron microscopy in 1946, are one of the extracellular vesicles (EVs) produced by many cells and have been the subject of many studies; initially, they were considered as cell wastes with the belief that cells produced exosomes to maintain homeostasis. Nowadays, it has been found that EVs secreted by different cells play a vital role in cellular communication and are usually secreted in both physiological and pathological conditions. Due to the presence of different markers and ligands on the surface of exosomes, they have paracrine, endocrine and autocrine effects in some cases. Immune cells, like other cells, can secrete exosomes that interact with surrounding cells via these vesicles. Immune system cells-derived exosomes (IEXs) induce different responses, such as increasing and decreasing the transcription of various genes and regulating cytokine production. This review deliberate the function of innate and acquired immune cells derived exosomes, their role in the pathogenesis of immune diseases, and their therapeutic appliances.

M2 Tumor Associate Macrophage- (TAM-) Derived lncRNA HISLA Promotes EMT Potential in Bladder Cancer

Background

Tumor-associated macrophages (TAMs) are M2-like phenotype macrophages which contribute to the tumor progression in tumor microenvironment. The precise mechanisms of TAMs were intricated, and recently, it has been illustrated that TAM-derived exosomal lncRNAs played pivotal roles in the tumor development. In the present study, we investigated the role of TAM-derived exosomal lncRNA HISLA in bladder cancer.

Materials and Methods

Effects of TAM exosomes and exosomal lncRNA HISLA on migration and invasion in bladder cells were detected by wound healing assay, transwell assay, and western blot assay. Differential expression of lncRNA HISLA in exosomes derived from M0 or TAMs was examined by qRT-PCR. Western blot assay was used to classify the precise molecular mechanisms.

Results

We found that TAM-derived exosomes significantly promote the migration and invasion abilities of bladder cells. Expression of epithelial-mesenchymal transition (EMT) markers was obviously affected by TAM exosome administration. Furthermore, we found that the expression of lncRNA HISLA was specifically elevated in TAM exosomes and TAM exosome-treated bladder cells. Silencing of lncRNA HISLA was found to suppress the processes of migration, invasion, and EMT in bladder cells. In addition, we found that β-catenin levels were downregulated, and Ser33 phosphorylated β-catenin levels were increased by HISLA siRNA treatment. At last, we found that HISLA stabilized β-catenin expression through preventing interaction between GSK3β and β-catenin.

Conclusion

In conclusion, our results investigated the prometastatic role of exosomal lncRNA HISLA derived from TAMs in bladder cancer and suggested TAM-derived HISLA as a promising therapeutic target of bladder cancer.

LINC01431 Promotes Histone H4R3 Methylation to Impede HBV Covalently Closed Circular DNA Transcription by Stabilizing PRMT1

Covalently closed circular DNA (cccDNA) is the transcriptional template of hepatitis B virus (HBV), which interacts with both host and viral proteins to form minichromosome in the nucleus and is resistant to antiviral agents. Identification of host factors involved in cccDNA transcriptional regulation is expected to prove a new venue for HBV therapy. Recent evidence suggests the involvement of long noncoding RNAs (lncRNAs) in mediating the interaction of host factors with various viruses, however, lncRNAs that HBV targets and represses cccDNA transcription have not been fully elucidated. Here, the authors identified LINC01431 as a novel host restriction factor for HBV transcription. Mechanically, LINC01431 competitively bound with type I protein arginine methyltransferase (PRMT1) to block the HBx-mediated PRMT1 ubiquitination and degradation. Consequently, LINC01431 increased the occupancy of PRMT1 on cccDNA, leading to enhanced H4R3me2a modification and reduced acetylation of cccDNA-bound histones, thereby repressing cccDNA transcription. In turn, to facilitate viral replication, HBV transcriptionally repressed LINC01431 expression by HBx-mediated repression of transcription factor Zinc fingers and homeoboxes 2 (ZHX2). Collectively, the study demonstrates LINC01431 as a novel epigenetic regulator of cccDNA minichromosome and highlights a feedback loop of HBx-LINC01431-PRMT1 in HBV replication, which provides potential therapeutic targets for HBV treatment.

ERBB2 S310F mutation independently activates PI3K/AKT and MAPK pathways through homodimers to contribute gallbladder carcinoma growth

Genomic instability and mutability are a prominent character of tumor. The whole-exosome sequence reveals that ERBB2 mutations are the representative mutations of gallbladder carcinoma, which takes potential targets for gallbladder carcinoma therapy. However, the roles of ERBB2 mutations are unclear in gallbladder carcinoma. We identified S310F mutation is the hottest mutation of ERBB2 mutations from TCGA PanCancer Altas data with 10,967 samples and our previous study with 157 gallbladder carcinoma samples. S310F mutation located in ERBB2 extracellular domain, promoted ERBB2 homodimerization and consequent auto-phosphorylation to activate the downstream PI3K/AKT and MAPK pathways, which was independent on ERBB1, ERBB3, and ERBB4. ERBB2 S310F mutation up-regulated aerobic glycolysis and promoted gallbladder carcinoma growth. Our study reveals the roles of ERBB2 S310F mutation, which is beneficial to ERBB2 S310F mutant gallbladder carcinoma therapy.

The Mechanisms of lncRNA-Mediated Multidrug Resistance and the Clinical Application Prospects of lncRNAs in Breast Cancer

Simple Summary

Multidrug resistance (MDR) is a major cause of breast cancer (BC) chemotherapy failure. Long noncoding RNAs (lncRNAs) have been shown closely related to the chemoresistance of BC. In this work, the mechanisms of lncRNA-mediated MDR in BC were elaborated from eight sections, including apoptosis, autophagy, DNA repair, cell cycle, drug efflux, epithelial-mesenchymal transition, epigenetic modification and the tumor microenvironment. Additionally, we also discuss the clinical significance of lncRNAs, which may be biomarkers for diagnosis, therapy and prognosis.

Abstract

Breast cancer (BC) is a highly heterogeneous disease and presents a great threat to female health worldwide. Chemotherapy is one of the predominant strategies for the treatment of BC; however, multidrug resistance (MDR) has seriously affected or hindered the effect of chemotherapy. Recently, a growing number of studies have indicated that lncRNAs play vital and varied roles in BC chemoresistance, including apoptosis, autophagy, DNA repair, cell cycle, drug efflux, epithelial-mesenchymal transition (EMT), epigenetic modification and the tumor microenvironment (TME). Although thousands of lncRNAs have been implicated in the chemoresistance of BC, a systematic review of their regulatory mechanisms remains to be performed. In this review, we systematically summarized the mechanisms of MDR and the functions of lncRNAs mediated in the chemoresistance of BC from the latest literature. These findings significantly enhance the current understanding of lncRNAs and suggest that they may be promising prognostic biomarkers for BC patients receiving chemotherapy, as well as therapeutic targets to prevent or reverse chemoresistance.

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

LINC01605 promotes aerobic glycolysis through LDHA in triple-negative breast cancer

Breast cancer is the most prevalent cancer diagnosed in women and the major malignancy that threatens women health, thus we explored the role of long noncoding RNA LINC01605 in triple‐negative breast cancer (TNBC). We collected tissue samples from TNBC patients and cultured breast cancer cells to detect LINC01605 levels by RT‐PCR. We then constructed LINC01605 knockdown and LINC01605 overexpressed TNBC cell lines, cell proliferation was measured by CCK‐8 and colony formation assays, cell migration and invasion were measured by Transwell assay, and aerobic glycolysis of cells was detected. Furthermore, a downstream target gene was found, and its role was confirmed by mouse allogeneic tumor formation. It discovered that LINC01605 expression was significantly increased in TNBC patients, and its high expression predicted a low survival prognosis for TNBC patients. Stable knockdown of LINC01605 remarkably inhibited cell proliferation, migration, and invasion, as well as aerobic glycolysis by inhibiting lactate dehydrogenase A in TNBC cell lines. Notably, knockdown of LINC01605 suppressed in vivo tumor formation and migration in TNBC transplanted mice. In conclusion, targeting long noncoding RNA LINC01605 might serve as a therapeutic candidate strategy to treat patients with TNBC.

The Role of Long Non-Coding RNAs in the Tumor Immune Microenvironment

Tumorigenesis is a complicated process caused by successive genetic and epigenetic alterations. The past decades demonstrated that the immune system affects tumorigenesis, tumor progression, and metastasis. Although increasing immunotherapies are revealed, only a tiny proportion of them are effective. Long non-coding RNAs (lncRNAs) are a class of single-stranded RNA molecules larger than 200 nucleotides and are essential in the molecular network of oncology and immunology. Increasing researches have focused on the connection between lncRNAs and cancer immunotherapy. However, the in-depth mechanisms are still elusive. In this review, we outline the latest studies on the functions of lncRNAs in the tumor immune microenvironment. Via participating in various biological processes such as neutrophil recruitment, macrophage polarization, NK cells cytotoxicity, and T cells functions, lncRNAs regulate tumorigenesis, tumor invasion, epithelial-mesenchymal transition (EMT), and angiogenesis. In addition, we reviewed the current understanding of the relevant strategies for targeting lncRNAs. LncRNAs-based therapeutics may represent promising approaches in serving as prognostic biomarkers or potential therapeutic targets in cancer, providing ideas for future research and clinical application on cancer diagnosis and therapies.

Non-coding RNAs and macrophage interaction in tumor progression

The macrophages are abundantly found in TME and their M2 polarization is in favor of tumor malignancy. On the other hand, non-coding RNAs (ncRNAs) can modulate macrophage polarization in TME to affect cancer progression. The miRNAs can dually induce/suppress M2 polarization of macrophages and by affecting various molecular pathways, they modulate tumor progression and therapy response. The lncRNAs can affect miRNAs via sponging and other molecular pathways to modulate macrophage polarization. A few experiments have also examined role of circRNAs in targeting signaling networks and affecting macrophages. The therapeutic targeting of these ncRNAs can mediate TME remodeling and affect macrophage polarization. Furthermore, exosomal ncRNAs derived from tumor cells or macrophages can modulate polarization and TME remodeling. Suppressing biogenesis and secretion of exosomes can inhibit ncRNA-mediated M2 polarization of macrophages and prevent tumor progression. The ncRNAs, especially exosomal ncRNAs can be considered as non-invasive biomarkers for tumor diagnosis.

Extracellular Vesicle-Mediated Mitochondrial Reprogramming in Cancer

Simple Summary

Mitochondria are important organelles involved in several key cellular processes including energy production and cell death regulation. For this reason, it is unsurprising that mitochondrial function and structure are altered in several pathological states including cancer. Cancer cells present variate strategies to generate sufficient energy to sustain their high proliferation rates. These adaptative strategies can be mediated by extracellular signals such as extracellular vesicles. These vesicles can alter recipient cellular behavior by delivering their molecular cargo. This review explores the different EV-mediated mitochondrial reprogramming mechanisms supporting cancer survival and progression.

Abstract

Altered metabolism is a defining hallmark of cancer. Metabolic adaptations are often linked to a reprogramming of the mitochondria due to the importance of these organelles in energy production and biosynthesis. Cancer cells present heterogeneous metabolic phenotypes that can be modulated by signals originating from the tumor microenvironment. Extracellular vesicles (EVs) are recognized as key players in intercellular communications and mediate many of the hallmarks of cancer via the delivery of their diverse biological cargo molecules. Firstly, this review introduces the most characteristic changes that the EV-biogenesis machinery and mitochondria undergo in the context of cancer. Then, it focuses on the EV-driven processes which alter mitochondrial structure, composition, and function to provide a survival advantage to cancer cells in the context of the hallmarks of cancers, such as altered metabolic strategies, migration and invasiveness, immune surveillance escape, and evasion of apoptosis. Finally, it explores the as yet untapped potential of targeting mitochondria using EVs as delivery vectors as a promising cancer therapeutic strategy.

m6A binding protein YTHDF2 in cancer

YT521-B homology domain family member 2 (YTHDF2) is an N⁶-methyladenosine (m⁶A)-binding protein that was originally found to regulate the stability of mRNA. Growing evidence has shown that YTHDF2 can participate in multifarious bioprocesses, including embryonic development, immune response, and tumor progression. Furthermore, YTHDF2 is closely associated with the proliferation, apoptosis, invasion, and migration of tumor cells, suggesting its significant role in cancers. YTHDF2 primarily relies on m⁶A modification to modulate signaling pathways in cancer cells. However, the expression and function of YTHDF2 in human malignancies remain controversial. Meanwhile, the underlying molecular mechanisms of YTHDF2 have not been elucidated. In this review, we principally summarized the biological functions and molecular mechanisms of YTHDF2 in tumors and discussed its prognostic and therapeutic values.

CD14-positive extracellular vesicles in bronchoalveolar lavage fluid as a new biomarker of acute respiratory distress syndrome

Recent studies have indicated that extracellular vesicles (EVs) may play a role in the pathogenesis of acute respiratory distress syndrome (ARDS). EVs have been identified as potential biomarkers of disease severity and prognosis in other pulmonary diseases. We sought to characterize the EV phenotype within bronchoalveolar lavage (BAL) fluid of patients with ARDS, and to determine whether BAL EV could be used as a potential biomarker in ARDS. BAL was collected from patients with sepsis with and without ARDS, and from esophagectomy patients postoperatively (of whom a subset later developed ARDS during hospital admission). BAL EVs were characterized with regard to size, number, and cell of origin. Patients with sepsis-related ARDS had significantly higher numbers of CD14⁺/CD81⁺ monocyte-derived BAL EV than patients with sepsis without ARDS (P = 0.015). However, the converse was observed in esophagectomy patients who later developed ARDS (P = 0.003). Esophagectomy patients who developed ARDS also had elevated CD31⁺/CD63⁺ and CD31⁺/CD81⁺ endothelial-derived BAL EV (P ≤ 0.02) compared with esophagectomy patients who did not develop ARDS. Further studies are required to determine whether CD31⁺ BAL EV may be a predictive biomarker for ARDS in esophagectomy patients. CD14⁺/CD81⁺ BAL EV numbers were significantly higher in those patients with sepsis-related ARDS who died during the 30 days following intensive care unit admission (P = 0.027). Thus, CD14⁺/CD81⁺ BAL EVs are a potential biomarker for disease severity and mortality in sepsis-related ARDS. These findings provide the impetus to further elucidate the contribution of these EVs to ARDS pathogenesis.

Untargeted metabolomics reveals alterations in the metabolic reprogramming of prostate cancer cells by double-stranded DNA-modified gold nanoparticles

Metabolic reprogramming plays an important role in the development of prostate cancer (PCa). However, there are few reports on the effects of nanomaterials as vectors on cancer metabolic reprogramming. Herein, a type of nanoparticle with good biocompatibility was synthesized by modifying the double-stranded of DNA containing a sulfhydryl group on the surface of gold nanoparticles (AuNPs-dsDNA) through salt-aging conjugation methods. The resultant AuNPs-dsDNA complexes possessed low toxicity to PC3 and DU145 cells in vitro. There was also no obvious hepatorenal toxicity after intravenous injection of AuNPs-dsDNA complexes in vivo, which indicated that these nanoparticles had good biological compatibilities. We investigated their biological functions using prostate cancer cells. Seahorse assay showed that AuNPs-dsDNA complexes could increase glycolysis and glycolysis capacity both in PC3 and DU145 cells. We further detected the expression of glycolysis-related genes by qPCR assay, and found that PKM2, PDHA, and LDHA were significantly upregulated. Furthermore, untargeted metabolomics revealed that PC (18:2(9Z,12Z)/18:2(9Z,12Z)) and PC (18:0/18:2 (9Z,12Z)) levels were decreased and inosinic acid level was increased in PC3 cells. Whereas (3S,6E,10E)-1,6,10,14-Phytatetraen-3-ol, Plasmenyl-PE 36:5 and Cer (d18:2/18:2) were decreased, PE 21:3 and 1-pyrrolidinecarboxaldehyde were increased in DU145 cells after co-culturing with AuNPs-dsDNA. In summary, we found that AuNPs and AuNPs-dsDNA complexes possibly regulate the metabolic reprogramming of cancer cells mainly through the lipid metabolic pathways, which could compensate for the previously mentioned phenomenon of enhanced glycolysis and glycolysis capacity. This will provide an important theoretical basis for our future research on the characteristic targeted design of nanomaterials for cancer metabolism.

NFκB activation by hypoxic small extracellular vesicles drives oncogenic reprogramming in a breast cancer microenvironment

Small extracellular vesicles (sEV) contribute to the crosstalk between tumor cells and stroma, but the underlying signals are elusive. Here, we show that sEV generated by breast cancer cells in hypoxic (sEVHYP), but not normoxic (sEVNORM) conditions activate NFκB in recipient normal mammary epithelial cells. This increases the production and release of inflammatory cytokines, promotes mitochondrial dynamics leading to heightened cell motility and disrupts 3D mammary acini architecture with aberrant cell proliferation, reduced apoptosis and EMT. Mechanistically, Integrin-Linked Kinase packaged in sEVHYP via HIF1α is sufficient to activate NFκB in the normal mammary epithelium, in vivo. Therefore, sEVHYP activation of NFκB drives multiple oncogenic steps of inflammation, mitochondrial dynamics, and mammary gland morphogenesis in a breast cancer microenvironment.

Energy Sources for Exosome Communication in a Cancer Microenvironment

Simple Summary

Exosomal communication in the tumor microenvironment plays a crucial role in cancer development, progression, and metastasis, and is achieved by either short-distance communication with neighboring cells or long-distance communication with distant organs. Nevertheless, how exosomes gain energy to establish such communication and the different sources of energy are unclear. Recently, a handful of studies have demonstrated the presence of mitochondria, adenosine triphosphate, and glycolytic enzymes, which may serve as potential energy sources for exosomes. This review clarifies how exosomes maintain their structural integrity and stability during their intracellular communication, and reviews evidence of their energy source.

Abstract

Exosomes are crucial extracellular vesicles (EVs) with a diameter of approximately 30–200 nm. They are released by most cell types in their extracellular milieu and carry various biomolecules, including proteins and nucleic acids. Exosomes are increasingly studied in various diseases, including cancer, due to their role in local and distant cell–cell communication in which they can promote tumor growth, cancer progression, and metastasis. Interestingly, a tremendous number of exosomes is released by malignant cancer cells, and these are then taken up by autologous and heterologous recipient stromal cells such as immune cells, cancer stem cells, and endothelial cells. All these events demand an enormous amount of energy and require that exosomes remain stable while having the capacity to reach distant sites and cross physical barriers. Nevertheless, there is a dearth of research pertaining to the energy sources of exosomes, and questions remain about how they maintain their motility in the tumor microenvironment (TME) and beyond. Moreover, exosomes can produce adenosine triphosphate (ATP), an important energy molecule required by all cells, and mitochondria have been identified as one of the exosomal cargoes. These findings strengthen the prospect of exosomal communication via transfer of mitochondria and the bioenergetics of target recipient cells. In the TME, the accumulation of ATP and lactate may facilitate the entry of exosomes into cancer cells to promote metastasis, as well as help to target cancer cells at the tumor site. This review highlights how exosomes obtain sufficient energy to thrive in the TME and communicate with distant physiological destinations.

Overexpression of cytosolic long noncoding RNA cytb protects against pressure-overload-induced heart failure via sponging microRNA-103-3p

Long noncoding RNAs (lncRNAs) play crucial roles in cardiovascular diseases. To date, only limited studies have reported the role of mitochondria-derived lncRNAs in heart failure (HF). In the current study, recombinant adeno-associated virus 9 was used to manipulate lncRNA cytb (lnccytb) expression in vivo. Fluorescence in situ hybridization (FISH) assay was used to determine the location of lnccytb, while microRNA (miRNA) sequencing and bioinformatics analyses were applied to identify the downstream targets. The competitive endogenous RNA (ceRNA) function of lnccytb was evaluated by biotin-coupled miRNA pull-down assays and luciferase reporter assays. Results showed that lnccytb expression was decreased in the heart of mice with transverse aortic constriction (TAC), as well as in the heart and plasma of patients with HF. FISH assay and absolute RNA quantification via real-time reverse transcription PCR suggested that the reduction of the lnccytb transcripts mainly occurred in the cytosol. Upregulation of cytosolic lnccytb attenuated cardiac dysfunction in TAC mice. Moreover, overexpression of cytosolic lnccytb in cardiomyocytes alleviated isoprenaline-induced reactive oxidative species (ROS) production and hypertrophy. Mechanistically, lnccytb acted as a ceRNA via sponging miR-103-3p, ultimately mitigating the suppression of PTEN by miR-103-3p. In summary, we demonstrated that the overexpression of cytosolic lnccytb could ameliorate HF.

Zeb1-induced metabolic reprogramming of glycolysis is essential for macrophage polarization in breast cancer

Aerobic glycolysis (the Warburg effect) has been demonstrated to facilitate tumor progression by producing lactate, which has important roles as a proinflammatory and immunosuppressive mediator. However, how aerobic glycolysis is directly regulated is largely unknown. Here, we show that ectopic Zeb1 directly increases the transcriptional expression of HK2, PFKP, and PKM2, which are glycolytic rate-determining enzymes, thus promoting the Warburg effect and breast cancer proliferation, migration, and chemoresistance in vitro and in vivo. In addition, Zeb1 exerts its biological effects to induce glycolytic activity in response to hypoxia via the PI3K/Akt/HIF-1α signaling axis, which contributes to fostering an immunosuppressive tumor microenvironment (TME). Mechanistically, breast cancer cells with ectopic Zeb1 expression produce lactate in the acidic tumor milieu to induce the alternatively activated (M2) macrophage phenotype through stimulation of the PKA/CREB signaling pathway. Clinically, the expression of Zeb1 is positively correlated with dysregulation of aerobic glycolysis, accumulation of M2-like tumor-associated macrophages (TAMs) and a poor prognosis in breast cancer patients. In conclusion, these findings identify a Zeb1-dependent mechanism as a driver of breast cancer progression that acts by stimulating tumor–macrophage interplay, which could be a viable therapeutic target for the treatment of advanced human cancers.

Long noncoding RNA LINC00930 promotes PFKFB3-mediated tumor glycolysis and cell proliferation in nasopharyngeal carcinoma

Background

Metabolic reprogramming is a hallmark of cancer. However, the roles of long noncoding RNAs (lncRNAs) in cancer metabolism, especially glucose metabolism remain largely unknown.

Results

In this study, we identified and functionally characterized a novel metabolism-related lncRNA, LINC00930, which was upregulated and associated with tumorigenesis, lymphatic invasion, metastasis, and poor prognosis in nasopharyngeal carcinoma (NPC). Functionally, LINC00930 was required for increased glycolysis activity and cell proliferation in multiple NPC models in vitro and in vivo. Mechanistically, LINC00930 served as a scaffold to recruit the RBBP5 and GCN5 complex to the PFKFB3 promoter and increased H3K4 trimethylation and H3K9 acetylation levels in the PFKFB3 promoter region, which epigenetically transactivating PFKFB3, and thus promoting glycolytic flux and cell cycle progression. Clinically, targeting LINC00930 and PFKFB3 in combination with radiotherapy induced tumor regression.

Conclusions

Collectively, LINC00930 is mechanistically, functionally and clinically oncogenic in NPC. Targeting LINC00930 and its pathway may be meaningful for treating patients with NPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02282-9.

Metabolism in tumor-associated macrophages

Macrophages functionally adapt to a diverse set of signals, a process that is critical for their role in maintaining or restoring tissue homeostasis. This process extends to cancer, where macrophages respond to a series of inflammatory and metabolic cues that direct a maladaptive healing response. Tumor-associated macrophages (TAMs) have altered glucose, amino acid, and lipid metabolic profiles, and interfering with this metabolic shift can blunt the ability of macrophages to promote tumor growth, metastasis, and the creation of an immunosuppressive microenvironment. Here we will review changes in metabolites and metabolic pathways in TAMs and link these with the phenotypic and functional properties of the cells. We will also discuss current strategies targeting TAM metabolism as a therapeutic intervention in cancer.

IL-2 Modulates TAMs Derived Exosomal MiRNAs to Ameliorate Hepatocellular Carcinoma Development and Progression

Background. Interleukin-2 (IL-2) is proved to play an irreplaceable role in antitumor regulation in numerous experimental and clinical trials. Tumor-associated macrophages (TAMs) are able to release exosomes to promote the development and progression of hepatocellular carcinoma (HCC) as essential component of microenvironment. In this study, our intention is to explore the effects of the exosomes from TAMs with IL-2 treatment on HCC development. TAMs were collected and cultured from HCC tissues. The exosomes from the TAMs treated with IL-2 (Exo^IL2-TAM) or not (Exo^TAM) were identified and used to treat HCC cells in vivo and in vitro. The proliferation, apoptosis, and metastasis of HCC cells were measured. The changes of miRNAs in exosomes were explored to clarify the possible mechanisms. Both decrease of cell proliferation and metastasis and increase of apoptosis were observed with Exo^IL2-TAM treatment compared with Exo^TAMin vivo and in vitro. miR-375 was obviously augmented in Exo^IL2-TAM and HCC cells treated with Exo^IL2-TAM. Taken together, IL-2 may modulate exosomal miRNAs from TAMs to ameliorate hepatocellular carcinoma development. This study provides a new perspective to explain the mechanism by which IL-2 inhibits hepatocellular carcinoma and implies the potential clinical value of exosomal miRNAs released by TAMs.