The functions of autophagy at the tumour-immune interface

Autophagy inhibition amplifies anti-tumor immunity effect of dinutuximab beta on neuroblastoma via the VEGFR/AKT/mTOR and ROS/NF-κB pathways

Dinutuximab beta has shown limited efficacy in treating high-risk neuroblastoma (NB). Combining autophagy inhibitors with immune checkpoint inhibitors (ICIs) has proven effective in many malignancies. However, the anti-tumor effects of autophagy inhibition in conjunction with anti-GD2 immunotherapy remain unknown. In this study, dinutuximab beta induces anti-proliferation and anti-EMT activity in NB cells. Dinutuximab beta also triggers autophagy in NB cells, and inhibition of the VEGFR pathway with anlotinib amplifies dinutuximab beta-induced autophagy. In addition, dinutuximab beta induces the synthesis of the chemokine CXCL9 and the infiltration of CD8+ T cells. Mechanistically, dinutuximab beta inhibits the VEGFR/AKT/mTOR and ROS/NF-κB pathways. Furthermore, autophagy inhibition by CQ enhances CXCL9 expression and anti-tumor T cell responses of single anti-GD2 therapy in vitro and in vivo. Collectively, this study suggests autophagy inhibitors may be a promising strategy for enhancing therapeutic efficacy in NB in conjunction with anti-GD2 immunotherapy.

Bioinformatics for the Identification of STING-Related Genes in Diabetic Retinopathy

PURPOSE

Diabetic retinopathy (DR) is the most common complication of diabetes mellitus. Stimulator of interferon genes (STING) plays an important regulatory role in the transcription of several genes. This study aimed to mine and identify hub genes relevant to STING in DR.

METHODS

The STING-related genes (STING-RGs) were extracted from MSigDB database. Differentially expressed STING-RGs (DE-STING-RGs) were filtered by overlapping differentially expressed genes (DEGs) between DR and NC specimens and STING-RGs. A PPI network was established to mine hub genes. The ability of the hub genes to differentiate between DR and NC specimens was evaluated. Additionally, a ceRNA network was established to investigate the regulatory mechanisms of hub genes. Subsequently, the discrepancies in immune infiltration between DR and NC specimens were further explored. Additionally, we performed drug predictions. Finally, RT-qPCR of peripheral blood samples was used to validate the bioinformatics results.

RESULTS

A grand total of four genes (IKBKG, STAT6, NFKBIA, and FCGR2A) related to STING were identified for DR. The AUC values of all four hub genes were greater than 0.7, which indicated that the diagnostic value was acceptable. The ceRNA network contained four hub genes, 170 miRNAs, and 135 lncRNAs. In addition, immunoinfiltration analysis demonstrated that the abundance of activated B cells was notably different between the DR and NC specimens. Moreover, 32 drugs were included in the drug-gene network, with twelve drugs targeting STAT6, nine drugs targeting NFKBIA, four drugs targeted IKBKG, and seven drugs targeted FCGR2A. The expression of the four hub genes in blood samples determined by RT-qPCR was consistent with our analysis.

CONCLUSION

In conclusion, four hub genes (IKBKG, STAT6, NFKBIA, and FCGR2A) related to STING with a diagnostic value for DR were identified by bioinformatics analysis, which might provide new insights into the evaluation and treatment of DR.

Palm oil as part of a high-fat diet: advances and challenges, or possible risks of pathology?

Nutritional status disorders have the most significant impact on the development of cardiovascular and oncologic diseases; therefore, the interest in the study of palm oil as among the leading components of nutrition has been increasing. The data examined in this review were sourced from the Scopus, SCIE (Web of Science), PubMed and PubMed Central, MEDLINE, CAPlus/SciFinder, and Embase databases; experts in the field; bibliographies; and abstracts from review analyses from the past 15 years. This review summarizes recent research data focusing on the quantitative and qualitative composition of nutrition of modern humans; concepts of the relationship between high-fat diets and disorders of insulin functioning and transport and metabolism of fatty acids; analyses of data regarding the palmitic acid (16:0) to oleic acid (18:1) ratio; and the effect of diet based on palm oil consumption on cardiovascular risk factors and lipid and lipoprotein levels. Several studies suggest a potential vector contributing to the transmission of maternal, high-fat-diet-induced, addictive-like behaviors and obesogenic phenotypes across generations. The relationship between cholesterol accumulation in lysosomes that may lead to lysosome dysfunction and inhibition of the autophagy process is analyzed, as is the progression of inflammatory diseases, atherosclerosis, nonalcoholic liver inflammation, and obesity with associated complications. Data are discussed from analyses of differences between rodent models and human population studies in the investigated different effects of palm oil consumption as a high-fat diet component. A conclusion is reached that the results cannot be generalized in human population studies because no similar effects were observed. Although there are numerous published reports, more studies are necessary to elucidate the complex regulatory mechanisms in digestive and nutrition processes, because there are great differences in lipoprotein profiles between rodents and humans, which makes it difficult to reproduce the pathology of many diseases caused by different types of the high-fat diet.

Why and how citrate may sensitize malignant tumors to immunotherapy

Immunotherapy, either alone or in combination with chemotherapy, has demonstrated limited efficacy in a variety of solid cancers. Several factors contribute to explaining primary or secondary resistance. Among them, cancer cells, whose metabolism frequently relies on aerobic glycolysis, promote exhaustion of cytotoxic immune cells by diverting the glucose in the tumor microenvironment (TME) to their own profit, while secreting lactic acid that sustains the oxidative metabolism of immunosuppressive cells. Here, we propose to combine current treatment based on the use of immune checkpoint inhibitors (ICIs) with high doses of sodium citrate (SCT) because citrate inhibits cancer cell metabolism (by targeting both glycolysis and oxidative metabolism) and may active anti-tumor immune response. Indeed, as showed in preclinical studies, SCT reduces cancer cell growth, promoting cell death and chemotherapy effectiveness. Furthermore, since the plasma membrane citrate carrier pmCIC is mainly expressed in cancer cells and low or not expressed in immune and non-transformed cells, we argue that the inhibition of cancer cell metabolism by SCT may increase glucose availability in the TME, thus promoting functionality of anti-tumor immune cells. Concomitantly, the decrease in the amount of lactic acid in the TME may reduce the functionality of immunosuppressive cells. Preclinical studies have shown that SCT can enhance the anti-tumor immune response through an enhancement of T cell infiltration and activation, and a repolarization of macrophages towards a TAM1-like phenotype. Therefore, this simple and cheap strategy may have a major impact to increase the efficacy of current immunotherapies in human solid tumors and we encourage testing it in clinical trials.

Asystematic review and meta-analysis of clinical prognostic factors linked to extravesical recurrence after radical nephroureterectomy to treat upper tract urothelial carcinoma

Objective

Numerous studies have investigated predictors of intravesical recurrence following radical nephrectomy (RNU) in patients with upper urinary tract uroepithelial carcinoma (UTUC). In contrast, extravesical recurrence (EUR) has received less focus. Consequently, this study aims to evaluate the significant predictors of EUR after RNU through a systematic review of the literature and a meta-analysis.

Methodology

We conducted a computerized bibliographic search across PubMed, Embase, and Cochrane databases to identify reports that include detailed results from multivariate analyses of predictors of EUR. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the AMSTAR (Assessing the Methodological Quality of Systematic Reviews) criteria, we selected thirteen retrospective studies, each with a sample size exceeding 100 cases. Using Review Manager 5.4 software, we performed cumulative analyses of available HR and their corresponding 95% confidence intervals to evaluate potential predictors of EUR.

Results

Our findings indicate that patient-specific predictors include preoperative Ki-67 with a HR of 3.61 (P = 0.003), neutrophil-to-lymphocyte ratio with an HR of 2.20 (P = 0.0005), and glomerular filtration rate with an HR of 3.35 (P = 0.0009). Tumor-specific predictors identified were tumor stage with an HR of 4.67 (P < 0.00001), lymphovascular invasion with an HR of 2.37 (P = 0.004), and lymph node status with an HR of 2.68 (P < 0.0001). Regarding treatment-specific predictors, positive surgical margins were associated with an HR of 3.97 (P = 0.0005), and adjuvant chemotherapy was associated with an HR of 1.65 (P = 0.03).

Discussion

Our study identified three significant predictors across patient, tumor, and treatment dimensions for extravesical recurrence following radical nephroureterectomy in patients with upper urinary tract uroepithelial carcinoma. We hypothesize that history of bladder cancer, platelet-to-lymphocyte ratio, and urinary cytology could also be strong predictors of post- RNU extravesical recurrence in patients with upper UTUC, assuming adequate sample size and controlled heterogeneity. This research aims to provide urological clinicians with enhanced guidance for postoperative decision-making.

A new perspective on the therapeutic potential of tumor metastasis: targeting the metabolic interactions between TAMs and tumor cells

Tumor-associated macrophages (TAMs) undergo metabolic reprogramming, encompassing glucose, amino acid, fatty acid metabolism, tricarboxylic acid (TCA) cycle, purine metabolism, and autophagy, within the tumor microenvironment (TME). The metabolic interdependencies between TAMs and tumor cells critically influence macrophage recruitment, differentiation, M2 polarization, and secretion of epithelial-mesenchymal transition (EMT)-related factors, thereby activating intratumoral EMT pathways and enhancing tumor cell invasion and metastasis. Tumor cell metabolic alterations, including hypoxia, metabolite secretion, aerobic metabolism, and autophagy, affect the TME's metabolic landscape, driving macrophage recruitment, differentiation, M2 polarization, and metabolic reprogramming, ultimately facilitating EMT, invasion, and metastasis. Additionally, macrophages can induce tumor cell EMT by reprogramming their aerobic glycolysis. Recent experimental and clinical studies have focused on the metabolic interactions between macrophages and tumor cells to control metastasis and inhibit tumor progression. This review highlights the regulatory role of TAM-tumor cell metabolic codependencies in EMT, offering valuable insights for TAM-targeted therapies in highly metastatic tumors. Modulating the metabolic interplay between tumors and TAMs represents a promising therapeutic strategy for treating patients with metastatic cancers.

Mannan-Decorated Lipid Calcium Phosphate Nanoparticle Vaccine Increased the Antitumor Immune Response by Modulating the Tumor Microenvironment

With the rapid development of tumor immunotherapy, nanoparticle vaccines have attracted much attention as potential therapeutic strategies. A systematic review and analysis must be carried out to investigate the effect of mannose modification on the immune response to nanoparticles in regulating the tumor microenvironment, as well as to explore its potential clinical application in tumor therapy. Despite the potential advantages of nanoparticle vaccines in immunotherapy, achieving an effective immune response in the tumor microenvironment remains a challenge. Tumor immune escape and the overexpression of immunosuppressive factors limit its clinical application. Therefore, our review explored how to intervene in the immunosuppressive mechanism in the tumor microenvironment through the use of mannan-decorated lipid calcium phosphate nanoparticle vaccines to improve the efficacy of immunotherapy in patients with tumors and to provide new ideas and strategies for the field of tumor therapy.

Emerging dimensions of autophagy in melanoma

Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-β: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.

CIRBP Increases the synthesis and secretion of steroid hormones by in yak granulaso cells

As a regulatory protein that upregulates transcription in response to various stresses, cold-induced RNA-binding protein (CIRBP) is involved in a variety of physiological pathological processes in cells. However, little is known about the role of CIRBP in regulating autophagy and the synthesis and secretion of ovarian steroid hormones (estradiol E2 and progesterone P4). This study aimed to explore whether the synthetic secretion of ovarian steroid hormones is related to CIRBP-regulated autophagy. We detected the differential expression of CIRBP, LC3, E2 and P4 in YGCs cultured at mild low temperature (32 °C) for 6 and 12 h. CIRBP, LC3, E2 and P4 expression was increased in response to low temperature in YGCs. In order to illustrate that the changes in secretion of E2/P4 and autophagy might be caused by CIRBP induced by low temperature, we overexpressed CIRBP in YGCs cultured in vitro to detect its effects on autophagy and steroid hormone synthesis and secretion. We found that overexpression of CIRBP can induce autophagy of YGCs and enhance the synthesis and secretion of E2 and P4, suggesting that mild hypothermia may activate autophagy by inducing the expression of CIRBP and enhance the synthesis and secretion of E2 and P4. To further explore the relationship between CIRBP regulated autophagy and steroid hormone synthesis and secretion, we verified it by regulating autophagy. The results showed that Inhibition of autophagy significantly reversed CIRBP overexpression-enhanced autophagy and synthetic secretion of E2, P4 in YGCs, while activated autophagy showed similar results to overexpression of CIRBP. In conclusion, our data suggest that autophagy is involved in the synthesis and secretion of YGCs E2 and P4 and is associated with overexpression of CIRBP.

The Prognosis of Cancer Depends on the Interplay of Autophagy, Apoptosis, and Anoikis within the Tumor Microenvironment

Within the tumor microenvironment, the fight between the immune system and cancer influences tumor transformation. Metastasis formation is an important stage in the progression of cancer. This process is aided by cellular detachment and resistance to anoikis, which are achieved by altering intercellular signaling. Autophagy, specifically pro-survival autophagy, aids cancer cells in developing treatment resistance. Numerous studies have shown that autophagy promotes tumor growth and resistance to anoikis. To regulate protective autophagy, cancer-related genes phosphorylate both pro- and anti-apoptotic proteins. Apoptosis, a type of controlled cell death, eliminates damaged or unwanted cells. Anoikis is a type of programmed cell death in which cells lose contact with the extracellular matrix. The dysregulation of these cellular pathways promotes tumor growth and spread. Apoptosis, anoikis, and autophagy interact meticulously and differently depending on the cellular circumstances. For instance, autophagy can protect cancer cells from apoptosis by removing cellular components that are damaged and might otherwise trigger apoptotic pathways. Similarly, anoikis dysregulation can trigger autophagy by causing cellular harm and metabolic stress. In order to prevent or treat metastatic disease, specifically, targeting these cellular mechanisms may present a promising prospect for cancer therapy. This review discourses the state of our understanding of the molecular and cellular mechanisms underlying tumor transformation and the establishment of metastatic tumors. To enhance the prognosis for cancer, we highlight and discuss potential therapeutic approaches that target these processes and genes involved in them.

Fusobacterium nucleatum facilitates proliferation and autophagy by activating miR-361-3p/NUDT1 axis through oxidative stress in hypopharyngeal squamous cell carcinoma

BACKGROUND

To investigate how Fusobacterium nucleatum (Fn) promotes oxidative stress and mediates proliferation and autophagy in hypopharyngeal squamous cell carcinoma (HPSCC).

METHODS

The prognosis for 82 HPSCC cases was retrospectively analyzed. HPSCC cell line FaDu was co-cultured with Fn. Knockdown of NUDT1 (shNUDT1 group) was done after observing DNA damage response. CCK8 and tumorigenesis assays for proliferation observation, mitochondria ROS (MitoROS) measurement to examine intracellular oxidative stress, and ELISA to analyze concentration of 8-oxo-2'-deoxyguanosine (8-oxo-dG) in cells. Dual-luciferase reporter assays clarified miR-361-3p connection with NUDT1. Autophagy flow was observed using electron microscopy and related proteins.

RESULTS

Fn was highly associated with NUDT1. The shNUDT1 group experienced lower proliferation compared with normal FaDu (NC group) in vivo and in vitro. The shNUDT1 group showed 8-oxo-dG and γH2AX to be elevated. Intracellular ROS decreased in shNUDT1Fn group when compared to Fn group. Upregulating miR-361-3p could suppress NUDT1 expression and downstream proliferation and autophagy. Fn modulated miR-361-3p via OH-, which could be proven by H2O2 assay and N-acetylcysteine.

CONCLUSIONS

Higher Fn in HPSCC patients suggests poorer prognosis. NUDT1 might affect cell proliferation and autophagy and modulate DNA damage response. The oxidative stress induced miR-361-3p/NUDT1 axis is first introduced in microbiome-carcinoma research.

Autophagy-amplifying nanoparticles evoke immunogenic cell death combined with anti-PD-1/PD-L1 for residual tumors immunotherapy after RFA

Incomplete radiofrequency ablation (IRFA) triggers mild protective autophagy in residual tumor cells and results in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and causes resistance to anti-PD-1/PDL1 therapy, which bringing a great clinical challenge in residual tumors immunotherapy. Mild autophagy activation can promote cancer cell survival while further amplification of autophagy contributes to immunogenic cell death (ICD). To this regard, we constructed active targeting zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) loaded with STF62247 or both STF62247 and BMS202, namely STF62247@ZIF-8/PEG-FA (SZP) or STF62247-BMS202@ZIF-8/PEG-FA (SBZP) NPs. We found that SZP NPs inhibited proliferation and stimulated apoptosis of residual tumor cells exposed to sublethal heat stress in an autophagy-dependent manner. Further results discovered that SZP NPs could amplify autophagy in residual tumor cells and evoke their ICD, which dramatically boosted the maturation of dendritic cells (DCs). Through vaccination experiments, we found for the first time that vaccination with heat + SZP treatment could efficiently suppress the growth of new tumors and establish long-term immunological memory. Furthermore, SBZP NPs could remarkably promote the ICD of residual tumor cells, obviously activate the anti-tumor immune microenvironment, and significantly inhibit the growth of residual tumors. Thus, amplified autophagy coupled with anti-PD-1/PDL1 therapy is potentially a novel strategy for treating residual tumors after IRFA.

A pyroptosis-related gene signature that predicts immune infiltration and prognosis in colon cancer

Background

Colon cancer (CC) is a highly heterogeneous malignancy associated with high morbidity and mortality. Pyroptosis is a type of programmed cell death characterized by an inflammatory response that can affect the tumor immune microenvironment and has potential prognostic and therapeutic value. The aim of this study was to evaluate the association between pyroptosis-related gene (PRG) expression and CC.

Methods

Based on the expression profiles of PRGs, we classified CC samples from The Cancer Gene Atlas and Gene Expression Omnibus databases into different clusters by unsupervised clustering analysis. The best prognostic signature was screened and established using least absolute shrinkage and selection operator (LASSO) and multivariate COX regression analyses. Subsequently, a nomogram was established based on multivariate COX regression analysis. Next, gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were performed to explore the potential molecular mechanisms between the high- and low-risk groups and to explore the differences in clinicopathological characteristics, gene mutation characteristics, abundance of infiltrating immune cells, and immune microenvironment between the two groups. We also evaluated the association between common immune checkpoints and drug sensitivity using risk scores. The immunohistochemistry staining was utilized to confirm the expression of the selected genes in the prognostic model in CC.

Results

The 1163 CC samples were divided into two clusters (clusters A and B) based on the expression profiles of the 33 PRGs. Genes with prognostic value were screened from the DEGs between the two clusters, and an eight PRGs prognostic model was constructed. GSEA and GSVA of the high- and low-risk groups revealed that they were mainly enriched in inflammatory response-related pathways. Compared to those in the low-risk group, patients in the high-risk group had worse overall survival, an immunosuppressive microenvironment, and worse sensitivity to immunotherapy and drug treatment.

Conclusion

Our findings provide a foundation for future research targeting pyroptosis and new insights into prognosis and immunotherapy from the perspective of pyroptosis in CC.

Emerging trends and research foci in autophagy of pancreatic cancer: a bibliometric and visualized study

Objective

The purpose of this study was to analyze the trends by year, country, institution, journal, reference and keyword in publications on the autophagy of pancreatic cancer (PC) and to predict future research hotspots.

Methods

The Web of Science Core Collection was used to search for publications. The contributions of various countries/regions, institutes, authors, identified research hotspots, and promising future trends were analyzed using the VOSviewer1.6.16 and CiteSpace6.6.R2 programs. We also summarized autophagy relevant clinical trials of PC.

Results

A total of 1293 papers on the autophagy of PC published between 2013 and 2023 were included in the study. The average number of citations per article was 33.76. The China had the most publications, followed by USA, and a total of 50 influential articles were identified through co-citation analysis. Clustering analysis revealed clusters of keywords: metabolic reprogramming and ER stress, mTOR-mediated apoptosis, extracellular trap as the most concerned clusters. The co-occurrence cluster analysis showed pancreatic stellate cell, autophagy-dependent ferroptosis, autophagy-related pathway, metabolic rewiring, on-coding RNA as the highly concerned research topics in recently.

Conclusion

The number of publications and research interest have generally increased over the past few years. The China and USA have made prominent contributions to the study of the autophagy of PC. The current research hotspots mainly focus not only on the related modulation, metabolic reprogramming, ferroptosis of tumor cells themselves, but also on tumor microenvironments such as autophagy associated pancreatic stellate cells and new treatments targeting autophagy.

Autoimmunity and Carcinogenesis: Their Relationship under the Umbrella of Autophagy

The immune system and autophagy share a functional relationship. Both innate and adaptive immune responses involve autophagy and, depending on the disease's origin and pathophysiology, it may have a detrimental or positive role on autoimmune disorders. As a "double-edged sword" in tumors, autophagy can either facilitate or impede tumor growth. The autophagy regulatory network that influences tumor progression and treatment resistance is dependent on cell and tissue types and tumor stages. The connection between autoimmunity and carcinogenesis has not been sufficiently explored in past studies. As a crucial mechanism between the two phenomena, autophagy may play a substantial role, though the specifics remain unclear. Several autophagy modifiers have demonstrated beneficial effects in models of autoimmune disease, emphasizing their therapeutic potential as treatments for autoimmune disorders. The function of autophagy in the tumor microenvironment and immune cells is the subject of intensive study. The objective of this review is to investigate the role of autophagy in the simultaneous genesis of autoimmunity and malignancy, shedding light on both sides of the issue. We believe our work will assist in the organization of current understanding in the field and promote additional research on this urgent and crucial topic.

Exploiting Autophagy-Dependent Neoantigen Presentation in Tumor Microenvironment

Autophagy constitutes a well-known homeostatic and catabolic process that is responsible for degradation and recycling of cellular components. It is a key regulatory mechanism for several cellular functions, whereas its dysregulation is associated with tumorigenesis, tumor-stroma interactions and resistance to cancer therapy. A growing body of evidence has proven that autophagy affects the tumor microenvironment, while it is also considered a key factor for function of several immune cells, such as APCs, T-cells, and macrophages. Moreover, it is implicated in presentation of neo-antigens of tumor cells in both MHC-I and MHC-II in dendritic cells (DCs) in functional activity of immune cells by creating T-cell memory, as well as in cross-presentation of neo-antigens for MHC-I presentation and the internalization process. Currently, autophagy has a crucial role in immunotherapy. Emergence of cancer immunotherapy has already shown some remarkable results, having changed therapeutic strategy in clinical practice for several cancer types. Despite these promising long-term responses, several patients seem to lack the ability to respond to immune checkpoint inhibitors. Thus, autophagy through neo-antigen presentation is a potential target in order to strengthen or attenuate the effects of immunotherapy against different types of cancer. This review will shed light on the recent advances and future directions of autophagy-dependent neo-antigen presentation and consequently its role in immunotherapy for malignant tumors.

[Cheng's Juanbi Decoction enhances autophagy in rheumatoid arthritis fibroblast-like syn-oviocytes by suppressing the PI3K/Akt/mTOR signal axis]

OBJECTIVE

To study the regulatory effect of Cheng's Juanbi Decoction (JBT) on autophagy in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) and role of PI3K/Akt/mTOR signaling axis in the mechanism mediating this effect.

METHODS

CCK8 assay was used to determine the optimal concentration and treatment time of JBT for inhibiting the viability of RA- FLS. The effect of freeze-dried powder of JBT, RAPA, or both on morphology of the autophagosomes in RA-FLS was observed under transmission electron microscope, and the changes in the number of autophagosomes and autolysosomes were observed with autophagy double-labeled adenovirus experiment. RT-qPCR and Western blotting were used to detect the expression levels of the related indicators.

RESULTS

The results of CCK8 assay showed that treatment with 0.5 mg/mL JBT for 12 h produced the optimal effect for inhibiting RA-FLS viability. Observation with transmission electron microscope and the results of the autophagy double-labeled adenovirus experiment both showed the presence of a small number of autophagosomes in control RA-FLS group, and treatment with JBT significantly increased the number of autophagosomes and lowered the number of autophagolysosomes in the cells. Compared with the control cells and the cells treated with JBT or RAPA alone, the cells treated with both JBT and RAPA showed significantly decreased mRNA levels of PI3K, Akt and mTOR (P < 0.01) but without significant changes in their protein expressions (P > 0.05); the combined treatment significantly inhibited the protein expressions of p-PI3K, p-Akt, p-mTOR, and P62 (P < 0.05) and upregulated the protein expressions of Beclin-1 and LC3B (P < 0.05) in the cells.

CONCLUSION

JBT can inhibit the survival rate of RA-FLS and increase the level of autophagy possibly through a mechanism that down-regulates PI3K/Akt/mTOR signaling pathway.

Recent advances in glioblastoma multiforme therapy: A focus on autophagy regulation

Despite conventional treatment options including chemoradiation, patients with the most aggressive primary brain tumor, glioblastoma multiforme (GBM), experience an average survival time of less than 15 months. Regarding the malignant nature of GBM, extensive research and discovery of novel treatments are urgently required to improve the patients' prognosis. Autophagy, a crucial physiological pathway for the degradation and recycling of cell components, is one of the exciting targets of GBM studies. Interventions aimed at autophagy activation or inhibition have been explored as potential GBM therapeutics. This review, which delves into therapeutic techniques to block or activate autophagy in preclinical and clinical research, aims to expand our understanding of available therapies battling GBM.

Polyethylenimine, an Autophagy-Inducing Platinum-Carbene-Based Drug Carrier with Potent Toxicity towards Glioblastoma Cancer Stem Cells

The difficulty involved in the treatment of many tumours due to their recurrence and resistance to chemotherapy is tightly linked to the presence of cancer stem cells (CSCs). This CSC sub-population is distinct from the majority of cancer cells of the tumour bulk. Indeed, CSCs have increased mitochondrial mass that has been linked to increased sensitivity to mitochondrial targeting compounds. Thus, a platinum-based polyethylenimine (PEI) polymer-drug conjugate (PDC) was assessed as a potential anti-CSC therapeutic since it has previously displayed mitochondrial accumulation. Our results show that CSCs have increased specific sensitivity to the PEI carrier and to the PDC. The mechanism of cell death seems to be necrotic in nature, with an absence of apoptotic markers. Cell death is accompanied by the induction of a protective autophagy. The interference in the balance of this pathway, which is highly important for CSCs, may be responsible for a partial reversion of the stem-like phenotype observed with prolonged PEI and PDC treatment. Several markers also indicate the cell death mode to be capable of inducing an anti-cancer immune response. This study thus indicates the potential therapeutic perspectives of polycations against CSCs.

Regulation of autophagy fires up the cold tumor microenvironment to improve cancer immunotherapy

Immunotherapies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cells, have revolutionized the treatment of patients with advanced and metastatic tumors resistant to traditional therapies. However, the immunosuppressed tumor microenvironment (TME) results in a weak response to immunotherapy. Therefore, to realize the full potential of immunotherapy and obstacle barriers, it is essential to explore how to convert cold TME to hot TME. Autophagy is a crucial cellular process that preserves cellular stability in the cellular components of the TME, contributing to the characterization of the immunosuppressive TME. Targeted autophagy ignites immunosuppressive TME by influencing antigen release, antigen presentation, antigen recognition, and immune cell trafficking, thereby enhancing the effectiveness of cancer immunotherapy and overcoming resistance to immunotherapy. In this review, we summarize the characteristics and components of TME, explore the mechanisms and functions of autophagy in the characterization and regulation of TME, and discuss autophagy-based therapies as adjuvant enhancers of immunotherapy to improve the effectiveness of immunotherapy.

SOCS5 contributes to temozolomide resistance in glioblastoma by regulating Bcl-2-mediated autophagy

Temozolomide (TMZ) is the primary chemotherapeutic drug for treating glioblastoma (GBM); however, the final clinical outcome is considerably limited by the poor response and resistance to TMZ. Although autophagy is thought to be associated with chemotherapy resistance and cancer cell survival, the precise molecular mechanisms underlying this process remain elusive. The suppressor of cytokine signaling (SOCS) family is widely distributed in vivo and exerts a range of effects on tumors; however, the expression pattern and role of SOCS in GBM remains unknown. In this study, we determined that high SOCS5 expression level was associated with poor prognosis and TMZ resistance in GBM. TMZ induced an increase in SOCS5 expression level and upregulated autophagy during the acquisition of drug resistance. The observed increase in the extent of autophagy was mediated by SOCS5. Mechanistically, SOCS5 enhances the transcription of Bcl-2. Knockdown of SOCS5 inhibited TMZ chemoresistance in GBM cells through the inhibition of Bcl-2 recruited autophagy; upregulation of Bcl-2 blocked this effect. In summary, our findings revealed the involvement and underlying mechanism of SOCS5 in TMZ resistance. SOCS5 plays a critical role in GBM chemoresistance and may serve as a novel prognostic marker and therapeutic target for chemotherapeutically treating drug-resistant GBM.

Magnesium-Assisted Cisplatin Inhibits Bladder Cancer Cell Survival by Modulating Wnt/β-Catenin Signaling Pathway

Magnesium, an essential mineral micronutrient, plays a role in the activation of various transporters and enzymes. The present study aimed to investigate the possibility of applying magnesium to enhance the efficacy of cisplatin which is still ranked as one of the major chemotherapeutic drugs for bladder cancer patients. Results showed that the survival rate and colony formation of bladder cancer cells were reduced by combinatorial treatment with cisplatin and magnesium chloride (MgCl₂). The proportion of apoptotic cells was also increased in UC3 bladder cancer cells treated with a combination of cisplatin and MgCl₂. Most importantly, a marked decrease in nuclear β-catenin was observed in cells that received cisplatin treatment. In addition, the nuclear β-catenin in cisplatin treated cells was further down-regulated by supplementing MgCl₂. 6-bromoindirubin-3′-oxime (BIO), an inhibitor of glycogen synthase kinase-3 (GSK-3) that activates the Wnt/β-catenin signaling pathway by modulating β-catenin activity, was thus applied to further exploit the role of this signaling pathway in magnesium aided cancer treatment. The survival rate of bladder cancer cells was decreased by BIO treatment at concentrations of 1.0, 2.5 and 5.0 μM accompanied by increased β-catenin expression. However, the expression of β-catenin in MgCl₂-treated cells was lower than in untreated cells under the same BIO concentration. The expression of cleaved caspase-3, cleaved caspase-9 and microtubule-associated protein 1 light chain 3- II (LC3-II) was highest in cells treated with MgCl₂ and 5.0 μM BIO among the examined groups. Our findings reveal that magnesium could contribute to cisplatin-based chemotherapy by moderately regulating the Wnt/β-catenin signaling pathway.

Autophagy in Xp11 translocation renal cell carcinoma: from bench to bedside

Xp11 translocation renal cell carcinoma (tRCC) characterized by the rearrangement of the TFE3 is recently identified as a unique subtype of RCC that urgently requires effective prevention and treatment strategies. Therefore, determining suitable therapeutic targets and fully understanding the biological significance of tRCC is essential. The importance of autophagy is increasingly acknowledged because it shows carcinogenic activity or suppressor effect. Autophagy is a physiological cellular process critical to maintaining cell homeostasis, which is involved in the lysosomal degradation of cytoplasmic organelles and macromolecules via the lysosomal pathway, suggesting that targeting autophagy is a potential therapeutic approach for cancer therapies. However, the underlying mechanism of autophagy in tRCC is still ambiguous. In this review, we summarize the autophagy-related signaling pathways associated with tRCC. Moreover, we examine the roles of autophagy and the immune response in tumorigenesis and investigate how these factors interact to facilitate or prevent tumorigenesis. Besides, we review the findings regarding the treatment of tRCC via induction or inhibition of autophagy. Hopefully, this study will shed some light on the functions and implications of autophagy and emphasize its role as a potential molecular target for therapeutic intervention in tRCC.

Modulation of Cancer Cell Autophagic Responses by Graphene-Based Nanomaterials: Molecular Mechanisms and Therapeutic Implications

Simple Summary

Graphene-based nanomaterials (GNM) are one-to-several carbon atom-thick flakes of graphite with at least one lateral dimension <100 nm. The unique electronic structure, high surface-to-volume ratio, and relatively low toxicity make GNM potentially useful in cancer treatment. GNM such as graphene, graphene oxide, graphene quantum dots, and graphene nanofibers are able to induce autophagy in cancer cells. During autophagy the cell digests its own components in organelles called lysosomes, which can either kill cancer cells or promote their survival, as well as influence the immune response against the tumor. However, a deeper understanding of GNM-autophagy interaction at the mechanistic and functional level is needed before these findings could be exploited to increase GNM effectiveness as cancer therapeutics and drug delivery systems. In this review, we analyze molecular mechanisms of GNM-mediated autophagy modulation and its possible implications for the use of GNM in cancer therapy.

Abstract

Graphene-based nanomaterials (GNM) are plausible candidates for cancer therapeutics and drug delivery systems. Pure graphene and graphene oxide nanoparticles, as well as graphene quantum dots and graphene nanofibers, were all able to trigger autophagy in cancer cells through both transcriptional and post-transcriptional mechanisms involving oxidative/endoplasmic reticulum stress, AMP-activated protein kinase, mechanistic target of rapamycin, mitogen-activated protein kinase, and Toll-like receptor signaling. This was often coupled with lysosomal dysfunction and subsequent blockade of autophagic flux, which additionally increased the accumulation of autophagy mediators that participated in apoptotic, necrotic, or necroptotic death of cancer cells and influenced the immune response against the tumor. In this review, we analyze molecular mechanisms and structure–activity relationships of GNM-mediated autophagy modulation, its consequences for cancer cell survival/death and anti-tumor immune response, and the possible implications for the use of GNM in cancer therapy.

Pterygium-The Good, the Bad, and the Ugly

Pterygium is a multifaceted pathology that displays apparent conflicting characteristics: benign (e.g., self-limiting and superficial), bad (e.g., proliferative and potentially recurrent) and ugly (e.g., signs of preneoplastic transformation). The natural successive question is: why are we lacking reports showing that pterygium lesions become life-threatening through metastasis, especially since pterygium has considerable similarities with UV-related malignancies on the molecular level? In this review, we consider how our pathophysiological understanding of the benign pterygium pathology overlaps with ocular surface squamous neoplasia and skin cancer. The three UV-related disorders share the same initial insult (i.e., UV radiation) and responsive repair mechanisms to the ensuing (in)direct DNA damage. Their downstream apoptotic regulators and other cellular adaptations are remarkably alike. However, a complicating factor in understanding the fine line between the self-limiting nature of pterygium and the malignant transformation in other UV-related diseases is the prominent ambiguity in the pathological evaluation of pterygium biopsies. Features of preneoplastic transformation (i.e., dysplasia) are used to define normal cellular reactions (i.e., atypia and metaplasia) and vice versa. A uniform grading system could help in unraveling the true nature of this ancient disease and potentially help in identifying the earliest intervention point possible regarding the cellular switch that drives a cell’s fate towards cancer.

The functions of autophagy at the tumour-immune interface

Autophagy is frequently induced in the hypoxic tumour microenvironment. Accumulating evidence reveals important functions of autophagy at the tumour-immune interface. Herein, we propose an update on the roles of autophagy in modulating tumour immunity. Autophagy promotes adaptive resistance of established tumours to the cytotoxic effects of natural killer cells (NKs), macrophages and effector T cells. Increased autophagic flux in tumours dampen their immunogenicity and inhibits the expansion of cytotoxic T lymphocytes (CTLs) by suppressing the activation of STING type I interferon signalling (IFN-I) innate immune sensing pathway. Autophagy in suppressive tumour-infiltrating immune subsets maintains their survival through metabolic remodelling. On the other hand, autophagy is involved in the antigen processing and presentation process, which is essential for anti-tumour immune responses. Genetic deletion of autophagy induces spontaneous tumours in some models. Thus, the role of autophagy is context-dependent. In summary, our review has revealed the dichotomous roles of autophagy in modulating tumour immunity. Broad targeting of autophagy may not yield maximal benefits. The characterization of specific genes regulating tumour immunogenicity and innovation in targeted delivery of autophagy inhibitors into certain tumours are among the most urgent tasks to sensitize cold cancers to immunotherapy.