Autophagy inhibits TLR4-mediated invasiveness of oral cancer cells via the NF-κB pathway

Endoplasmic reticulum stress induced autophagy in cancer and its potential interactions with apoptosis and ferroptosis

The endoplasmic reticulum (ER) is a dynamic organelle that is a site of the synthesis of proteins and lipids, contributing to the regulation of proteostasis, lipid metabolism, redox balance, and calcium storage/-dependent signaling events. The disruption of ER homeostasis due to the accumulation of misfolded proteins in the ER causes ER stress which activates the unfolded protein response (UPR) system through the activation of IRE1, PERK, and ATF6. Activation of UPR is observed in various cancers and therefore, its association with process of carcinogenesis has been of importance. Tumor cells effectively utilize the UPR system to overcome ER stress. Moreover, ER stress and autophagy are the stress response mechanisms operating together to maintain cellular homeostasis. In human cancers, ER stress-driven autophagy can function as either pro-survival or pro-death in a context-dependent manner. ER stress-mediated autophagy can have crosstalk with other types of cell death pathways including apoptosis and ferroptosis. In this connection, the present review has evaluated the role of ER stress in the regulation of autophagy-mediated tumorigenesis and its interactions with other cell death mechanisms such as apoptosis and ferroptosis. We have also comprehensively discussed the effect of ER stress-mediated autophagy on cancer progression and chemotherapeutic resistance.

Progression of m6A in the tumor microenvironment: hypoxia, immune and metabolic reprogramming

Recently, N6-methyladenosine (m6A) has aroused widespread discussion in the scientific community as a mode of RNA modification. m6A comprises writers, erasers, and readers, which regulates RNA production, nuclear export, and translation and is very important for human health. A large number of studies have found that the regulation of m6A is closely related to the occurrence and invasion of tumors, while the homeostasis and function of the tumor microenvironment (TME) determine the occurrence and development of tumors to some extent. TME is composed of a variety of immune cells (T cells, B cells, etc.) and nonimmune cells (tumor-associated mesenchymal stem cells (TA-MSCs), cancer-associated fibroblasts (CAFs), etc.). Current studies suggest that m6A is involved in regulating the function of various cells in the TME, thereby affecting tumor progression. In this manuscript, we present the composition of m6A and TME, the relationship between m6A methylation and characteristic changes in TME, the role of m6A methylation in TME, and potential therapeutic strategies to provide new perspectives for better treatment of tumors in clinical work.

Induction of CX3CL1 expression by LPS and its impact on invasion and migration in oral squamous cell carcinoma

Purpose: This study aimed to explore the expression of CX3CL1 induced by lipopolysaccharide (LPS) in oral squamous cell carcinoma (OSCC) and its impact on biological characteristics such as invasion and migration, taking the foundation for new targets for the treatment and prognosis of OSCC. Methods: This study utilized a variety of techniques, including bioinformatics, molecular biology, and cell experiments, to investigate the expression of CX3CL1 and its receptor CX3CR1 in OSCC patients' cancer tissues or OSCC cell lines. Extracting, organizing, and analyzing the TCGA database on the expression of CX3CL1 and its receptor CX3CR1 in cancer tissues and corresponding paracancerous normal tissues of OSCC patients by bioinformatics methods. The expression of CX3CL1 in cancerous and normal tissues of OSCC patients was verified by IHC, and the changes in mRNA and protein expression of CX3CL1 and its receptor CX3CR1 in OSCC cell lines were detected before and after lipopolysaccharide LPS stimulation by RT-PCR, ELISA, and WB. Changes in cell biological behavior by overexpression of CX3CL1 in OSCC cell lines were detected by CCK-8, Transwell, scratch healing assay, and cloning assay. The effects of overexpressing cell lines on the AKT pathway and Epithelial-mesenchymal Transition (EMT)-related protein expression before and after LPS stimulation were detected by Western Blot. Results: (1) CX3CL1 and its receptor CX3CR1 were found to be downregulated in OSCC tissues of patients or OSCC cell lines. (2) After LPS stimulation, CX3CL1 gene expression increased in both OSCC cell lines, while CX3CR1 expression remained unchanged. (3) OSCC cell lines overexpressing CX3CL1 showed changes in cell biological characteristics, including decreased proliferation, invasion, migration, and stemness, which were more pronounced after LPS stimulation. (4) Overexpression of CX3CL1 in OSCC cell lines decreased EMT-related protein expression and AKT phosphorylation. On the contrary were promoted by LPS stimulation. Conclusion: CX3CL1 and CX3CR1 are downregulated in OSCC cancer tissues and cell lines compared to adjacent normal tissues and cells. LPS stimulation increases CX3CL1 expression in OSCC cell lines, suggesting that inflammation may induce CX3CL1 expression and that the CX3CL1 gene may play an important role in OSCC progression. Overexpression of CX3CL1 inhibits OSCC cell proliferation, migration, invasion, and stemness, suggesting that CX3CL1 plays a critical role in suppressing OSCC development. CX3CL1 suppresses OSCC invasion and migration by affecting EMT progression and AKT phosphorylation, and partially reverse the process that LPS causes and affects the development of OSCC.

Galectins in epithelial-mesenchymal transition: roles and mechanisms contributing to tissue repair, fibrosis and cancer metastasis

Galectins are soluble glycan-binding proteins that interact with a wide range of glycoproteins and glycolipids and modulate a broad spectrum of physiological and pathological processes. The expression and subcellular localization of different galectins vary among tissues and cell types and change during processes of tissue repair, fibrosis and cancer where epithelial cells loss differentiation while acquiring migratory mesenchymal phenotypes. The epithelial-mesenchymal transition (EMT) that occurs in the context of these processes can include modifications of glycosylation patterns of glycolipids and glycoproteins affecting their interactions with galectins. Moreover, overexpression of certain galectins has been involved in the development and different outcomes of EMT. This review focuses on the roles and mechanisms of Galectin-1 (Gal-1), Gal-3, Gal-4, Gal-7 and Gal-8, which have been involved in physiologic and pathogenic EMT contexts.

TLR4 inhibited autophagy by modulating PI3K/AKT/mTOR signaling pathway in Gastric cancer cell lines

Toll-like receptors (TLRs) are pattern recognition receptors found on both immune and cancerous cells. Gastric cancer (GC) cells/tissues have been shown to exhibit elevated levels of TLR4. Here, we examined the role of TLR4 on autophagy and proliferation in GC cells. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) were used to determine TLR4 levels at different stages of GC cells/tissues as well as the levels of autophagy-related proteins (ARPs) and determine the underlying signaling mechanism. Proliferation was assessed via the CCK-8 assay. The protein and mRNA levels of ARPs were elucidated, followed by estimating the involved signaling pathways. Our results demonstrated that the modulation of the PI3K/AKT/mTOR pathway resulted from autophagy inhibition/induction, which was induced by the overexpression and knockdown of TLR4. Thus, TLR4 played a vital role in GC progression.

Polymorphisms and haplotypes of TLR-4/9 associated with bacterial infection, gingival inflammation/recession and oral cancer

BACKGROUND

The expression and SNPs of innate immunity genes TLR-4/9 for bacterial infection, gingival inflammation/gingival recession (GIGR), and oral squamous cell carcinoma (OSCC) are largely unknown.

PATIENTS AND METHOD

235 specimens (120 OSCC cases, among which 85 cases with either Porphyromonas gingivalis, Fusobacterium nucleatum or Treponema denticola infection and GIGR) and 115 healthy controls were used to know the expression and polymorphisms (TLR-4: N1:rs10759931, N2:rs11536889, N3:rs1927911, N4:rs4986790; TLR-9: N5:rs5743836, N6:rs352140, N7:rs187084 and N8:rs352139) of TLR-4/9 by western blot, RT-PCR, and allele-specific (AS)-PCR followed by sequencing.

RESULTS

Increased TLR-4/9 mRNA/protein expression, bacterial infection (BI) and GIGR were associated with OSCC incidence. One of the three BI and GIGR was observed in 70.83% of OSCC cases, whereas all the HC used were free from any of these three BI/GIGR. The N3: CT-genotype (Odds Ratio hereafter as O.R.=1.811, p = 0.0338), TT-genotype (O.R.=3.094, p = 0.0124), 'T'-allele (O.R.=1.821, p = 0.003), N4: AG-genotype (O.R.=2.015, p = 0.0222) and 'G'-allele (O.R.=1.86, p = 0.018) of TLR-4 as well as the N5: CC-genotype (O.R.=3.939, p = 0.0017), 'C'-allele (O.R.=1.839, p = 0.0042), N6: AA-genotype (O.R.=2.195, p = 0.0234), 'A'-allele (O.R.=1.569, p = 0.0163), N7: TC-genotype (O.R.=2.083, p = 0.0136), CC-genotype (O.R.=2.984, p = 0.003) and 'C'-allele (O.R.=1.885, p = 0.0008) of TLR-9 were associated with increased OSCC risk. Similarly, the N2:'C'-allele (O.R.=1.615, p = 0.0382), N3: TT-genotype (O.R.=2.829, p = 0.0336), 'T'-allele (O.R.=1.742, p = 0.0115), N4: AG-genotype (O.R.=2.221, p = 0.0147) and 'G'-allele (O.R.=1.890, p = 0.0238) of TLR-4 as well as the N5: CC-genotype (O.R.=2.830, p = 0.031), N6: AA-genotype (O.R.=2.6, p = 0.0122) and 'A'-allele (O.R.=1.746, p = 0.0064), N7:CC-genotype (O.R.2.706, p = 0.0111) and 'C'-allele (O.R. 1.774, p = 0.0055) of TLR-9 were correlated with GIGR and BI. TLR-4 (N1-N2-N3-N4: A-C-T-A (O.R.=2.1, p = 0.0069) and TLR-9 (N5-N6-N7-N8: T-A-C-A (O.R.=2.019, p = 0.0263); C-A-C-A (O.R.=6.0, p = 0.0084); C-A-C-G (O.R.=4.957, p = 0.0452) haplotypes were linked with OSCC vulnerability, while the TLR-4 (N1-N2-N3-N4: G-C-C-A (O.R.=0.5752, p = 0.0131) and TLR-9 (N5-N6-N7-N8: T-G-T-A (O.R.=0.5438, p = 0.0314); T-G-T-G (O.R.=0.5241, p = 0.036) haplotypes offered protection.

CONCLUSION

TLR-4/9 expression, polymorphisms, and BI-induced GIGR could increase OSCC risk. This may be used in pathogenesis and oral cancer prediction.

Identification of autophagy-related gene and lncRNA signatures in the prognosis of HNSCC

OBJECTIVE

The aim of this study was to identify prognostic autophagy-related genes and lncRNAs to predict clinical outcomes in head and neck squamous cell carcinoma (HNSCC).

SUBJECTS AND METHODS

Differentially expressed autophagy-related genes and autophagy-related lncRNAs were identified by comparing pare-carcinoma and carcinoma samples of HNSCC. And then, we constructed an ARG and an AR-lncRNA signature risk score. Receiver operating characteristic (ROC) curve analyses were performed to assess the prognostic prediction capacity. Gene Set Enrichment Analysis (GSEA) and Gene Ontology (GO) functional annotation were used to analysis the functions of ARGs and AR-lncRNAs.

RESULTS

Six ARGs and thirteen AR-lncRNAs were identified in the ARG and AR-lncRNA signatures, and overall survival (OS) in the high-risk group was significantly shorter than the low-risk group. ROC analysis showed the ARG and AR-lncRNA signatures have excellent ability of predicting the total OS of patients with HNSCC. What's more, GSEA and GO functional annotation proved that autophagy-related pathways are mainly enriched in the high-risk group.

CONCLUSIONS

These findings indicated that our ARG signature and AR-lncRNA signature could be considered to predict the prognosis of patients with HNSCC and provide a deep understanding of the biological mechanisms of autophagy in HNSCC.

Unravelling the roles of Autophagy in OSCC: A renewed perspective from mechanisms to potential applications

Oral squamous cell carcinoma (OSCC) is associated with a low survival rate and a high disability rate, making it a serious health burden, particularly in Southeast Asian countries. Therefore, improvements in the diagnosis, treatment, and prognosis prediction of OSCC are highly warranted. Autophagy has a significant impact on cancer development. Studies on autophagy in various human cancers have made outstanding contributions; however, the relationship between autophagy and OSCC remains to be explored. This review highlights the roles of autophagy in OSCC and discusses the relationship between autophagy and Epithelial–mesenchymal transition. Considering the lack of OSCC biomarkers, we focus on the studies involving OSCC-related bioinformatics analysis and molecular targets. Based on some classical targets, we summarize several key autophagy-related biomarkers with a considerable potential for clinical application, which may become the hotspot of OSCC research. In conclusion, we elaborate on the interrelationship between autophagy and OSCC and highlight the shortcomings of current studies to provide insights into the potential clinical strategies.

TLR4 Expression in Ex-Lichenoid Lesions-Oral Squamous Cell Carcinomas and Its Surrounding Epithelium: The Role of Tumor Inflammatory Microenvironment

Toll-like receptors (TLRs) regulate innate and adaptive immune responses. Moreover, TLRs can induce a pro-survival and pro-proliferation response in tumor cells. This study aims to investigate the expression of TLR4 in the epithelium surrounding oral squamous cell carcinomas (OSCC) in relation to its inflammatory microenvironment. This study included 150 human samples: 30 normal oral control (NOC), 38 non-lichenoid epithelium surrounding OSCC (NLE-OSCC), 28 lichenoid epithelium surrounding OSCC (LE-OSCC), 30 OSCC ex-non oral lichenoid lesion (OSCC Ex-NOLL), and 24 OSCC ex-oral lichenoid lesion (OSCC Ex-OLL). TLR4 expression was investigated by immunohistochemistry and the percentage of positive cells was quantified. In addition, a semiquantitative analysis of staining intensity was performed. Immunohistochemical analysis revealed that TLR4 is strongly upregulated in LE-OSCC as compared to normal control epithelium and NLE-OSCC. TLR4 expression was associated with the inflammatory environment, since the percentage of positive cells increases from NOC and NLE-OSCC to LE-OSCC, reaching the highest value in OSCC Ex-OLL. TLR4 was detected in the basal third of the epithelium in NLE-OSCC, while in LE-OSCC, TLR4 expression reached the intermediate layer. These results demonstrated that an inflammatory microenvironment can upregulate TLR4, which may boost tumor development.

Emerging Role of Autophagy in the Development and Progression of Oral Squamous Cell Carcinoma

Autophagy is a cellular catabolic process, which is characterized by degradation of damaged proteins and organelles needed to supply the cell with essential nutrients. At basal levels, autophagy is important to maintain cellular homeostasis and development. It is also a stress responsive process that allows the cells to survive when subjected to stressful conditions such as nutrient deprivation. Autophagy has been implicated in many pathologies including cancer. It is well established that autophagy plays a dual role in different cancer types. There is emerging role of autophagy in oral squamous cell carcinoma (OSCC) development and progression. This review will focus on the role played by autophagy in relation to different aspects of cancer progression and discuss recent studies exploring the role of autophagy in OSCC. It will further discuss potential therapeutic approaches to target autophagy in OSCC.

Autophagy in Tumor Immunity and Viral-Based Immunotherapeutic Approaches in Cancer

Autophagy is a fundamental catabolic process essential for the maintenance of cellular and tissue homeostasis, as well as directly contributing to the control of invading pathogens. Unsurprisingly, this process becomes critical in supporting cellular dysregulation that occurs in cancer, particularly the tumor microenvironments and their immune cell infiltration, ultimately playing a role in responses to cancer therapies. Therefore, understanding "cancer autophagy" could help turn this cellular waste-management service into a powerful ally for specific therapeutics. For instance, numerous regulatory mechanisms of the autophagic machinery can contribute to the anti-tumor properties of oncolytic viruses (OVs), which comprise a diverse class of replication-competent viruses with potential as cancer immunotherapeutics. In that context, autophagy can either: promote OV anti-tumor effects by enhancing infectivity and replication, mediating oncolysis, and inducing autophagic and immunogenic cell death; or reduce OV cytotoxicity by providing survival cues to tumor cells. These properties make the catabolic process of autophagy an attractive target for therapeutic combinations looking to enhance the efficacy of OVs. In this article, we review the complicated role of autophagy in cancer initiation and development, its effect on modulating OVs and immunity, and we discuss recent progress and opportunities/challenges in targeting autophagy to enhance oncolytic viral immunotherapy.

[Synergistic Effect of NF-κB Signaling Pathway Inhibitor and Oncolytic Measles Virus Vaccine Strain against Lung Cancer and Underlying Mechanisms]

背景与目的

肺癌已成为我国发病率和死亡率居首位的恶性肿瘤。能自我复制、选择性杀伤肿瘤的溶瘤病毒，是治疗恶性肿瘤的有效策略，而其中溶瘤麻疹病毒疫苗株因其良好的溶瘤效果，且对正常细胞无损伤或微损伤，已进入几项临床试验。本研究旨在探讨核转录因子κB（nuclear factor kappa B, NF-κB）信号通路抑制剂与溶瘤麻疹病毒疫苗株协同抗肺癌的作用及机制。

方法

应用Western blot方法检测MV-Edm感染人肺癌细胞A549和H1299并应用细胞自噬相关的siRNA或者应用NF-кB通路抑制剂PS1145后SQSTM1、p-IκBα、IκBα、PARP及BAX的表达水平，运用流式细胞术分析各组细胞凋亡率的变化，同时采用噻唑蓝[3-(4, 5)-dimethylthiahiazo(-z-y1)-3, 5-di-phenytetrazoliumromide, MTT]法检测各组细胞的存活率。

结果

Western blot结果显示MV-Edm感染人肺癌细胞A549和H1299后，自噬引起NF-κB通路的激活，进而抑制细胞凋亡。抑制细胞自噬可抑制NF-κB通路的激活，MV-Edm感染后p-IκBα表达水平随着感染时间有不同程度的升高，IκBα的表达水平则降低，NF-κB通路抑制剂PS1145可促进人肺癌细胞A549和H1299凋亡（P < 0.01），并增强其溶瘤效果。

结论

NF-κB信号通路抑制剂PS1145与溶瘤麻疹病毒疫苗株联合可促进人肺癌细胞A549和H1299凋亡，并增强其溶瘤效果。

Crosstalk between oncolytic viruses and autophagy in cancer therapy

Oncolytic viruses have attracted attention as a promising strategy in cancer therapy owing to their ability to selectively infect and kill tumor cells, without affecting healthy cells. They also exert their anti-tumor effects by releasing immunostimulatory molecules from dying cancer cells. Several regulatory mechanisms, such as autophagy, contribute to the anti-tumor properties of oncolytic viruses. Autophagy is a conserved catabolic process in responses to various stresses, such as nutrient deprivation, hypoxia, and infection that produces energy by lysosomal degradation of intracellular contents. Autophagy can support infectivity and replication of the oncolytic virus and enhance their anti-tumor effects via mediating oncolysis, autophagic cell death, and immunogenic cell death. On the other hand, autophagy can reduce the cytotoxicity of oncolytic viruses by providing survival nutrients for tumor cells. In his review, we summarize various types of oncolytic viruses in clinical trials, their mechanism of action, and autophagy machinery. Furthermore, we precisely discuss the interaction between oncolytic viruses and autophagy in cancer therapy and their combinational effects on tumor cells.

Role of Autophagy in the Microenvironment of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma, the most common type of oral cancer, affects more than 275,000 people per year worldwide. Oral squamous cell carcinoma is very aggressive, as most patients die after 3 to 5 years post-diagnosis. The initiation and progression of oral squamous cell carcinoma are multifactorial: smoking, alcohol consumption, and human papilloma virus infection are among the causes that promote its development. Although oral squamous cell carcinoma involves abnormal growth and migration of oral epithelial cells, other cell types such as fibroblasts and immune cells form the carcinoma niche. An underlying inflammatory state within the oral tissue promotes differential stress-related responses that favor oral squamous cell carcinoma. Autophagy is an intracellular degradation process that allows cancer cells to survive under stress conditions. Autophagy degrades cellular components by sequestering them in vesicles called autophagosomes, which ultimately fuse with lysosomes. Although several autophagy markers have been associated with oral squamous cell carcinoma, it remains unclear whether up- or down-regulation of autophagy favors its progression. Autophagy levels during oral squamous cell carcinoma are both timing- and cell-specific. Here we discuss how autophagy is required to establish a new cellular microenvironment in oral squamous cell carcinoma and how autophagy drives the phenotypic change of oral squamous cell carcinoma cells by promoting crosstalk between carcinoma cells, fibroblasts, and immune cells.

The identification of autophagy-related genes in the prognosis of oral squamous cell carcinoma

OBJECTIVES

The aim of this study was to identify prognostic autophagy-related genes and assess the ability of these genes to predict clinical outcomes in oral squamous cell carcinoma (OSCC).

SUBJECTS AND METHODS

The details of the human autophagy-related genes were obtained from the Human Autophagy Database. The Cancer Genome Atlas database was used to obtain the gene expression profiles and clinical data of patients. Prediction of biological functions of differentially expressed genes was performed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Prognosis-related genes were identified by Cox regression analysis, and the coefficient was applied to construct a prognostic risk score model. The median of the risk score was applied to distinguish between high- and low-risk groups. The Gene Expression Omnibus database, qRT-PCR and immunohistochemistry were used to validate the expression of key genes.

RESULTS

KEGG analyses revealed that differentially expressed genes were mainly enriched in autophagy-related pathways and virus infection. BAK1, BID, NKX2-3 and SPHK1 were identified. The risk score model showed that the high-risk score had poorer overall survival (Kaplan-Meier analysis, p = 1.79 × 10^-7 ). SPHK1 was upregulated in OSCC tissues and cells, and NXK2-3 was downregulated.

CONCLUSIONS

Autophagy-related gene expression profiles may be a potential biomarker for OSCC prognosis.