Snail acetylation by autophagy-derived acetyl-coenzyme A promotes invasion and metastasis of KRAS-LKB1 co-mutated lung cancer cells

ANXA5 predicts prognosis and immune response and mediates proliferation and migration in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy that often develops unnoticed. Typically, these tumors are identified at advanced stages, resulting in a relatively low chance of successful treatment. Anoikis serves as a natural defense against the spread of tumor cells, meaning circumventing anoikis can effectively inhibit tumor metastasis. Nonetheless, studies focusing on anoikis in the context of HNSCC remain scarce.

METHODS

Anoikis-related genes (ARGs) were identified by using the GeneCards and Harmonizome databases. Expression data of these genes and relevant clinical features were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A LASSO regression and a prognostic risk score model were developed to determine their prognostic significance. The analysis included the use of the CIBERSORT algorithm to quantify immune and stromal cell presence. Furthermore, in vitro and in vivo, we confirmed the expression and functional roles of proteins and mRNA of genes independently predictive of prognosis.

RESULTS

The study identified eight genes linked to prognosis (ANXA5, BAK1, CDKN2A, PPARG, CCR7, MAPK11, CRYAB, CRYBA1) and developed a prognostic model that effectively forecasts the survival outcomes for patients with HNSCC. A higher survival likelihood is associated with lower risk scores. In addition, a significant relationship was found between immune and risk score, and ANXA5 deletion promoted the killing of HNSCC cells by activated CD8+ T cells. During the screening process, 65 different chemotherapeutic drugs were found to have significant differences in IC50 values when comparing high- and low-risk categories. ANXA5 emerged as a gene with independent prognostic significance, exhibiting notably elevated protein and mRNA levels in HNSCC tissue compared to non-tumorous tissue. The suppression of ANXA5 gene activity resulted in a substantial decrease in both the growth and mobility of HNSCC cells. Animal model experiments demonstrated that inhibiting ANXA5 suppressed HNSCC growth and migration in vivo.

CONCLUSION

Through bioinformatics, a prognostic risk model of high precision was developed, offering valuable insights into the survival rates and immune responses in patients with HNSCC. ANXA5 is highlighted as a significant prognostic factor among the identified genes, indicating its promise as a potential therapeutic target for those with HNSCC.

SIRT1 silencing promotes EMT and Crizotinib resistance by regulating autophagy through AMPK/mTOR/S6K signaling pathway in EML4-ALK L1196M and EML4-ALK G1202R mutant non-small cell lung cancer cells

Most EML4-ALK rearrangement non-small cell lung cancer (NSCLC) patients inevitably develop acquired drug resistance after treatment. The main mechanism of drug resistance is the acquired secondary mutation of ALK kinase domain. L1196M and G1202R are classical mutation sites. We urgently need to understand the underlying molecular mechanism of drug resistance to study the therapeutic targets of mutant drug-resistant NSCLC cells. The silent information regulator sirtuin1 (SIRT1) can regulate the normal energy metabolism of cells, but its role in cancer is still unclear. In our report, it was found that the SIRT1 in EML4-ALK G1202R and EML4-ALK L1196M mutant drug-resistant cells was downregulated compared with EML4-ALK NSCLC cells. The high expression of SIRT1 was related to the longer survival time of patients with lung cancer. Activation of SIRT1 induced autophagy and suppressed the invasion and migration of mutant cells. Further experiments indicated that the activation of SIRT1 inhibited the phosphorylation level of mTOR and S6K by upregulating the expression of AMPK, thus activating autophagy. SIRT1 can significantly enhanced the sensitivity of mutant cells to crizotinib, improved its ability to promote apoptosis of mutant cells, and inhibited cell proliferation. In conclusion, SIRT1 is a key regulator of drug resistant in EML4-ALK L1196M and G1202R mutant cells. SIRT1 may be a novel therapeutic target for EML4-ALK drug resistant NSCLC.

Cadmium targeting transcription factor EB to inhibit autophagy-lysosome function contributes to acute kidney injury

INTRODUCTION

Environmental and occupational exposure to cadmium (Cd) has been shown to cause acute kidney injury (AKI). Previous studies have demonstrated that autophagy inhibition and lysosomal dysfunction are important mechanisms of Cd-induced AKI.

OBJECTIVES

Transcription factor EB (TFEB) is a critical transcription regulator that modulates autophagy-lysosome function, but its role in Cd-induced AKI is yet to be elucidated. Thus, in vivo and in vitro studies were conducted to clarify this issue.

METHODS AND RESULTS

Data firstly showed that reduced TFEB expression and nuclear translocation were evident in Cd-induced AKI models, accompanied by autophagy-lysosome dysfunction. Pharmacological and genetic activation of TFEB improved Cd-induced AKI via alleviating autophagy inhibition and lysosomal dysfunction, whereas Tfeb knockdown further aggravated this phenomenon, suggesting the key role of TFEB in Cd-induced AKI by regulating autophagy. Mechanistically, Cd activated mechanistic target of rapamycin complex 1 (mTORC1) to enhance TFEB phosphorylation and thereby inhibiting TFEB nuclear translocation. Cd also activated chromosome region maintenance 1 (CRM1) to promote TFEB nuclear export. Meanwhile, Cd activated general control non-repressed protein 5 (GCN5) to enhance nuclear TFEB acetylation, resulting in the decreased TFEB transcriptional activity. Moreover, inhibition of CRM1 or GCN5 alleviated Cd-induced AKI by enhancing TFEB activity, respectively.

CONCLUSION

In summary, these findings reveal that TFEB phosphorylation, nuclear export and acetylation independently suppress TFEB activity to cause Cd-induced AKI via regulating autophagy-lysosome function, suggesting that TFEB activation might be a promising treatment strategy for Cd-induced AKI.

CILP2 promotes hypertrophic scar through Snail acetylation by interaction with ACLY

BACKGROUND & AIMS

Hypertrophic scar (HS) is a skin fibroproliferative disorder occurring after burns, surgeries or traumatic injuries, and it has caused a tremendous economic and medical burden. Its molecular mechanism is associated with the abnormal proliferation and transition of fibroblasts and excessive deposition of extracellular matrix. Cartilage intermediate layer protein 2 (CILP2), highly homologous to cartilage intermediate layer protein 1 (CILP1), is mainly secreted predominantly from chondrocytes in the middle/deeper layers of articular cartilage. Recent reports indicate that CILP2 is involved in the development of fibrotic diseases. We investigated the role of CILP2 in the progression of HS.

METHODS AND RESULTS

It was found in this study that CILP2 expression was significantly higher in HS than in normal skin, especially in myofibroblasts. In a clinical cohort, we discovered that CILP2 was more abundant in the serum of patients with HS, especially in the early stage of HS. In vitro studies indicated that knockdown of CILP2 suppressed proliferation, migration, myofibroblast activation and collagen synthesis of hypertrophic scar fibroblasts (HSFs). Further, we revealed that CILP2 interacts with ATP citrate lyase (ACLY), in which CILP2 stabilizes the expression of ACLY by reducing the ubiquitination of ACLY, therefore prompting Snail acetylation and avoiding reduced expression of Snail. In vivo studies indicated that knockdown of CILP2 or ACLY inhibitor, SB-204990, significantly alleviated HS formation.

CONCLUSION

CILP2 exerts a vital role in hypertrophic scar formation and might be a detectable biomarker reflecting the progression of hypertrophic scar and a therapeutic target for hypertrophic scar.

Nobiletin targets SREBP1/ACLY to induce autophagy-dependent cell death of gastric cancer cells through PI3K/Akt/mTOR signaling pathway

BACKGROUND

Autophagy could sense metabolic conditions and safeguard cells against nutrient deprivation, ultimately supporting the survival of cancer cells. Nobiletin (NOB) is a kind of bioactive component of the traditional Chinese medicine Citri Reticulatae Pericarpium and has been proven to induce GC cell death by reducing de novo fatty acid synthesis in our previous study. Nevertheless, the precise mechanisms by which NOB induces cell death in GC cells still need further elucidation.

OBJECTIVES

To examine the mechanism by which NOB inhibits gastric cancer progression through the regulation of autophagy under the condition of lipid metabolism inhibition.

METHODS/ STUDY DESIGN

Proliferation was detected by the CCK-8 assay. RNA sequencing (RNA-seq) was used to examine signaling pathway changes. Electron microscopy and mRFP-GFP-LC3 lentiviral transfection were performed to observe autophagy in vitro. Western blot, plasmid transfection, immunofluorescence staining, and CUT & Tag-qPCR techniques were utilized to explore the mechanisms by which NOB affects GC cells. Molecular docking and molecular dynamics simulations were conducted to predict the binding mode of NOB and SREBP1. CETSA was adopted to verify the predicted of binding model. A patient-derived xenograft (PDX) model was employed to verify the therapeutic efficacy of NOB in vivo.

RESULTS

We conducted functional studies and discovered that NOB inhibited the protective effect of autophagy via the PI3K/Akt/mTOR axis in GC cells. Based on previous research, we found that the overexpression of ACLY abrogated the NOB-induced autophagy-dependent cell death. In silico analysis predicted the formation of a stable complex between NOB and SREBP1. In vitro assays confirmed that NOB treatment increased the thermal stability of SREBP1 at the same temperature conditions. Moreover, CUT&TAG-qPCR analysis revealed that NOB could inhibit SREBP1 binding to the ACLY promoter. In the PDX model, NOB suppressed tumor growth, causing SREBP1 nuclear translocation inhibition, PI3K/Akt/mTOR inactivation, and autophagy-dependent cell death.

CONCLUSION

NOB demonstrated the ability to directly bind to SREBP1, inhibiting its nuclear translocation and binding to the ACLY promoter, thereby inducing autophagy-dependent cell death via PI3K/Akt/mTOR pathway.

Beyond self‑eating: Emerging autophagy‑independent functions for the autophagy molecules in cancer (Review)

Autophagy is a conserved catabolic process that controls organelle quality, removes misfolded or abnormally aggregated proteins and is part of the defense mechanisms against intracellular pathogens. Autophagy contributes to the suppression of tumor initiation by promoting genome stability, cellular integrity, redox balance and proteostasis. On the other hand, once a tumor is established, autophagy can support cancer cell survival and promote epithelial‑to‑mesenchymal transition. A growing number of molecules involved in autophagy have been identified. In addition to their key canonical activity, several of these molecules, such as ATG5, ATG12 and Beclin‑1, also exert autophagy‑independent functions in a variety of biological processes. The present review aimed to summarize autophagy‑independent functions of molecules of the autophagy machinery and how the activity of these molecules can influence signaling pathways that are deregulated in cancer progression.

A novel insight into cancer therapy: Lipid metabolism in tumor-associated macrophages

The tumor immune microenvironment (TIME) can limit the effectiveness and often leads to significant side effects of conventional cancer therapies. Consequently, there is a growing interest in identifying novel targets to enhance the efficacy of targeted cancer therapy. More research indicates that tumor-associated macrophages (TAMs), originating from peripheral blood monocytes generated from bone marrow myeloid progenitor cells, play a crucial role in the tumor microenvironment (TME) and are closely associated with resistance to traditional cancer therapies. Lipid metabolism alterations have been widely recognized as having a significant impact on tumors and their immune microenvironment. Lipids, lipid derivatives, and key substances in their metabolic pathways can influence the carcinogenesis and progression of cancer cells by modulating the phenotype, function, and activity of TAMs. Therefore, this review focuses on the reprogramming of lipid metabolism in cancer cells and their immune microenvironment, in which the TAMs are especially concentrated. Such changes impact TAMs activation and polarization, thereby affecting the tumor cell response to treatment. Furthermore, the article explores the potential of targeting the lipid metabolism of TAMs as a supplementary approach to conventional cancer therapies. It reviews and evaluates current strategies for enhancing efficacy through TAMs' lipid metabolism and proposes new lipid metabolism targets as potential synergistic options for chemo-radiotherapy and immunotherapy. These efforts aim to stimulate further research in this area.

CD74-ROS1 L2026M mutant enhances autophagy through the MEK/ERK pathway to promote invasion, metastasis and crizotinib resistance in non-small cell lung cancer cells

The treatment of non-small cell lung cancer (NSCLC) patients harboring a proto-oncogene tyrosine-protein kinase c-ros oncogene 1 (ROS1) fusion gene has greatly benefited from the use of crizotinib. However, drug resistance inevitably occurs after 1 year of treatment. Clinical studies have shown that patients with an L2026M mutation in the ROS1 kinase domain account for about 6% of the total number of crizotinib-resistant cases, which is an important group that cannot be ignored. To explore the mechanism involved, we constructed the HLA class II histocompatibility antigen gamma chain (CD74)-ROS1 L2026M mutant gene by fusion polymerase chain reaction (PCR) and transfected it into H460 and A549 cells. We found that the invasion and metastasis abilities of drug-resistant cells were increased. The results of monodansylcadaverine (MDC) staining, Acridine orange (AO) staining, and western blot indicated that the autophagy level of CD74-ROS1 L2026M mutant NSCLC cells was increased compared with the CD74-ROS1 group, and the inhibition of autophagy could reverse the increased invasion and metastasis abilities caused by the L2026M mutation. In addition, the L2026M mutation led to excessive activation of the MEK/ERK pathway, and MEK inhibitors could reduce the autophagy level, invasion, and metastasis abilities of cells; additionally, this process could be blocked by rapamycin, an activator of autophagy. Furthermore, crizotinib treatment activated expression of Src homology region 2 domain-containing phosphatase-2 (SHP2; also known as PTPN11) to upregulate the MEK/ERK pathway, and the combination of MEK inhibitors and crizotinib increased apoptosis compared with crizotinib alone. In conclusion, our results indicate that the MEK/ERK pathway mediates the induction of invasion, metastasis, and crizotinib resistance through autophagy caused by CD74-ROS1 L2026M mutation in NSCLC cells, and targeting MEK could reverse these processes.

Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression

Epithelial Mesenchymal Transition (EMT) is a dedifferentiation process implicated in many physio-pathological conditions including tumor transformation. EMT is regulated by several extracellular mediators and under certain conditions it can be reversible. Autophagy is a conserved catabolic process in which intracellular components such as protein/DNA aggregates and abnormal organelles are degraded in specific lysosomes. In cancer, autophagy plays a controversial role, acting in different conditions as both a tumor suppressor and a tumor-promoting mechanism. Experimental evidence shows that deep interrelations exist between EMT and autophagy-related pathways. Although this interplay has already been analyzed in previous studies, understanding mechanisms and the translational implications of autophagy/EMT need further study. The role of autophagy in EMT is not limited to morphological changes, but activation of autophagy could be important to DNA repair/damage system, cell adhesion molecules, and cell proliferation and differentiation processes. Based on this, both autophagy and EMT and related pathways are now considered as targets for cancer therapy. In this review article, the contribution of autophagy to EMT and progression of cancer is discussed. This article also describes the multiple connections between EMT and autophagy and their implication in cancer treatment.

Paris polyphylla saponins II inhibits invasive, migration and epithelial-mesenchymal transition of melanoma cells through activation of autophagy

Malignant melanoma is a kind of malignant tumor derived from normal epidermal melanocytes or original nevus cells. It has a high degree of malignancy, rapid progress, dangerous condition, and poor prognosis. In recent years, the innovation of traditional Chinese medicine has broadened the scope and effect of tumor treatment. It is a hotspot and breakthrough to find new anti-tumor invasion and migration drugs from natural plants or traditional Chinese medicine. This study explored the role of PPII in promoting autophagy to inhibit EMT of melanoma cells, the role of the PI3K/Akt signaling pathway in the invasion and migration of melanoma cells induced by PPII. We found that PPII effectively inhibited the proliferation, invasion and migration of melanoma B16 and B16F10 in vitro, and induced autophagy. We also established the xenograft tumor and metastatic tumor model of C57BL/6 mice with B16F10 cells. Results showed that PPII effectively inhibited the growth of transplanted tumors, induced autophagy and inhibited the expression level of EMT related protein; Metastasis experiment showed that PPII inhibited the invasion and migration of B16F10, the effect of inhibiting lung metastasis is the most significant. Further mechanism studies showed that the inhibition of PPII on melanoma invasion and migration is related to its induction of autophagy and then inhibition of EMT.

Acetyl-CoA metabolism as a therapeutic target for cancer

Acetyl-coenzyme A (acetyl-CoA), an essential metabolite, not only takes part in numerous intracellular metabolic processes, powers the tricarboxylic acid cycle, serves as a key hub for the biosynthesis of fatty acids and isoprenoids, but also serves as a signaling substrate for acetylation reactions in post-translational modification of proteins, which is crucial for the epigenetic inheritance of cells. Acetyl-CoA links lipid metabolism with histone acetylation to create a more intricate regulatory system that affects the growth, aggressiveness, and drug resistance of malignancies such as glioblastoma, breast cancer, and hepatocellular carcinoma. These fascinating advances in the knowledge of acetyl-CoA metabolism during carcinogenesis and normal physiology have raised interest regarding its modulation in malignancies. In this review, we provide an overview of the regulation and cancer relevance of main metabolic pathways in which acetyl-CoA participates. We also summarize the role of acetyl-CoA in the metabolic reprogramming and stress regulation of cancer cells, as well as medical application of inhibitors targeting its dysregulation in therapeutic intervention of cancers.

Dihydroartemisinin inhibits liver cancer cell migration and invasion by reducing ATP synthase production through CaMKK2/NCLX

Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and mitochondrial sodium/calcium exchanger protein (NCLX) are key regulatory factors in calcium homeostasis. Finding natural drugs that target regulators of calcium homeostasis is critical. Dihydroartemisinin (DHA) is considered to have anticancer effects. The present study aimed to investigate the mechanism of DHA in regulating liver cancer migration and invasion. The present study used HepG2 and HuH-7 cells and overexpressed CaMKK2 and knocked down CaMKK2 and NCLX. The antiproliferative activity of DHA on liver cancer cells was assessed through colony formation and EdU assays. Cell apoptosis was detected through YO-PRO-1/PI staining. The levels of reactive oxygen species (ROS) were measured using a ROS detection kit (DCFH-DA fluorescent probe). Cell migratory and invasive abilities were examined using wound healing and Transwell assays. The ATP production of liver cancer cells was detected using ATP fluorescent probes. Cell microfilaments were monitored for changes using Actin-Tracker Green-488. The effects of DHA on the expression of CaMKK2, NCLX, sodium/potassium-transporting ATPase subunit α-1 (ATP1A1) and ATP synthase subunit d, mitochondrial (ATP5H) were determined by western blotting and reverse transcription-quantitative PCR. The results revealed that DHA significantly inhibited proliferation, reduced ROS levels and promoted apoptosis in liver cancer cells. CaMKK2 overexpression significantly enhanced the invasive and migratory ability of liver cancer cells, whereas DHA inhibited the pro-migratory effects of CaMKK2 overexpression. DHA significantly reduced the mitochondrial ATP production and altered the arrangement of microfilaments in liver cancer cells. In addition, DHA significantly decreased the expression of CaMKK2, NCLX, ATP1A1 and ATP5H. Furthermore, by knockdown experiments of NCLX the results demonstrated that CaMKK2 downregulated the expression of ATP1A1 and ATP5H in liver cancer cells through NCLX. In conclusion, DHA may reduce ATP synthase production via the CaMKK2/NCLX signaling pathway to inhibit the invasive phenotype of liver cancer cells. It is essential to further investigate the effectiveness of DHA in the anticancer mechanism of liver cancer cells.

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.

A cuproptosis-related lncRNA signature-based prognostic model featuring on metastasis and drug selection strategy for patients with lung adenocarcinoma

Introduction: Lung adenocarcinoma is a common cause of mortality in patients with cancer. Recent studies have indicated that copper-related cell death may not occur in the same way as previously described. Long non-coding RNAs (lncRNAs) play a key role in the occurrence and development of tumors; however, the relationship between cuproptosis and lncRNAs in tumorigenesis and lung adenocarcinoma (LUAD) treatment has not been well established. Our study aimed to construct a model to analyze the prognosis of lung adenocarcinoma in patients using a carcinogenesis-related lncRNA (CR) signature. Methods: The transcriptional profiles of 507 samples from The Cancer Genome Atlas were assessed. Cox regression and co-expression analyses, and the least absolute shrinkage and selection operator (LASSO) were used to filter the CR and develop the model. The expression status of the six prognostic CRs was used to classify all samples into high- and low-risk groups. The overall disease-free survival rate was compared between the two groups. The Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used to identify the pathways and mechanisms involved in this model. Subsequently, immunotherapy response, sensitivity, and correlation analyses for several anti-tumor medications were performed. In vitro experiments, including qPCR, were conducted in nine lung adenocarcinoma cell lines and 16 pairs of lung adenocarcinoma and para-carcinoma tissues. Results: After confirmation using the ROC curve, patients in the low-risk category benefited from both overall and disease-free survival. Gene Ontology analysis highlighted cell movement in the model. In the in vitro experiments, qPCR results showed the expression levels of six CRs in 16 pairs of carcinoma and para-carcinoma tissues, which were in accordance with the results of the model. AL138778.1 is a protective factor that can weaken the invasion and migration of A549 cells, and AL360270.1 is a hazardous factor that promotes the invasion and migration of A549 cells. According to this model, targeted treatments such as axitinib, gefitinib, linsitinib, pazopanib, and sorafenib may be more appropriate for low-risk patients. Conclusion: Six CR profiles (AL360270.1, AL138778.1, CDKN2A-DT, AP003778.1, LINC02718, and AC034102.8) with predictive values may be used to evaluate the prognosis of patients with lung adenocarcinoma undergoing therapy.

Recent Advances in Transcription Factors Biomarkers and Targeted Therapies Focusing on Epithelial-Mesenchymal Transition

Transcription factors involve many proteins in the process of transactivating or transcribing (none-) encoded DNA to initiate and regulate downstream signals, such as RNA polymerase. Their unique characteristic is that they possess specific domains that bind to specific DNA element sequences called enhancer or promoter sequences. Epithelial-mesenchymal transition (EMT) is involved in cancer progression. Many dysregulated transcription factors-such as Myc, SNAIs, Twists, and ZEBs-are key drivers of tumor metastasis through EMT regulation. This review summarizes currently available evidence related to the oncogenic role of classified transcription factors in EMT editing and epigenetic regulation, clarifying the roles of the classified conserved transcription factor family involved in the EMT and how these factors could be used as therapeutic targets in future investigations.

ANXA6/TRPV2 axis promotes lymphatic metastasis in head and neck squamous cell carcinoma by inducing autophagy

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is highly aggressive with a significant tropism of lymph nodes, which restricts treatment options and negatively impacts patient outcomes. Although progress has been made in understanding the molecular mechanisms underlying lymphatic metastasis (LM), these mechanisms remain elusive. ANXA6 is a scaffold protein that participates in tumor pathogenesis and autophagy regulation; however, how ANXA6 affects autophagy and LM in HNSCC cells remains unknown.

METHODS

RNA sequencing was performed on HNSCC clinical specimens with or without metastasis as well as on The Cancer Genome Atlas dataset to investigate ANXA6 expression and survival. Both in vitro and in vivo studies were performed to investigate the role of ANXA6 in the regulation of LM in HNSCC. The molecular mechanism by which ANXA6 interacts with TRPV2 was examined at the molecular level.

RESULTS

ANXA6 expression was significantly upregulated in HNSCC patients with LM and higher expression was associated with poor prognosis. ANXA6 overexpression promoted the proliferation and mobility of FaDu and SCC15 cells in vitro; however, ANXA6 knockdown retarded LM in HNSCC in vivo. ANXA6 induced autophagy by inhibiting the AKT/mTOR signaling pathway in HNSCC, thereby regulating the metastatic capability of the disease. Furthermore, ANXA6 expression positively correlated with TRPV2 expression both in vitro and in vivo. Lastly, TRPV2 inhibition reversed ANXA6-induced autophagy and LM.

CONCLUSIONS

These results indicate that the ANXA6/TRPV2 axis facilitates LM in HNSCC by stimulating autophagy. This study provides a theoretical basis for investigating the ANXA6/TRPV2 axis as a potential target for the treatment of HNSCC, as well as a biomarker for predicting LM.

Activation of ACLY by SEC63 deploys metabolic reprogramming to facilitate hepatocellular carcinoma metastasis upon endoplasmic reticulum stress

BACKGROUND

Tumor cells display augmented capability to maintain endoplasmic reticulum (ER) homeostasis and hijack ER stress pathway for malignant phenotypes under microenvironmental stimuli. Metabolic reprogramming is a well-known hallmark for tumor cells to provide specific adaptive traits to the microenvironmental alterations. However, it's unknown how tumor cells orchestrate metabolic reprogramming and tumor progression in response to ER stress. Herein, we aimed to explore the pivotal roles of SEC63-mediated metabolic remodeling in hepatocellular carcinoma (HCC) cell metastasis after ER stress.

METHODS

The expression levels of SEC63 in HCC tissues and adjacent non-cancerous tissues were determined by immunohistochemistry and western blot. The regulatory roles of SEC63 in HCC metastasis were investigated both in vitro and in vivo by RNA-sequencing, metabolites detection, immunofluorescence, and transwell migration/invasion analyses. GST pull-down, immunoprecipitation/mass spectrometry and in vivo ubiquitination/phosphorylation assay were conducted to elucidate the underlying molecular mechanisms.

RESULTS

We identified SEC63 as a new regulator of HCC cell metabolism. Upon ER stress, the phosphorylation of SEC63 at T537 by IRE1α pathway contributed to SEC63 activation. Then, the stability of ACLY was upregulated by SEC63 to increase the supply of acetyl-CoA and lipid biosynthesis, which are beneficial for improving ER capacity. Meanwhile, SEC63 also entered into nucleus for increasing nuclear acetyl-CoA production to upregulate unfolded protein response targets to improve ER homeostasis. Importantly, SEC63 coordinated with ACLY to epigenetically modulate expression of Snail1 in the nucleus. Consequently, SEC63 promoted HCC cell metastasis and these effects were reversed by ACLY inhibition. Clinically, SEC63 expression was significantly upregulated in HCC tissue specimens and was positively correlated with ACLY expression. Importantly, high expression of SEC63 predicted unfavorable prognosis of HCC patients.

CONCLUSIONS

Our findings revealed that SEC63-mediated metabolic reprogramming plays important roles in keeping ER homeostasis upon stimuli in HCC cells. Meanwhile, SEC63 coordinates with ACLY to upregulate the expression of Snail1, which further promotes HCC metastasis. Metastasis is crucial for helping cancer cells seek new settlements upon microenvironmental stimuli. Taken together, our findings highlight a cancer selective adaption to ER stress as well as reveal the potential roles of the IRE1α-SEC63-ACLY axis in HCC treatment.

Posttranslational regulation of liver kinase B1 (LKB1) in human cancer

Liver kinase B1 (LKB1) is a serine-threonine kinase that participates in multiple cellular and biological processes, including energy metabolism, cell polarity, cell proliferation, cell migration, and many others. LKB1 is initially identified as a germline-mutated causative gene in Peutz-Jeghers syndrome (PJS) and is commonly regarded as a tumor suppressor due to frequent inactivation in a variety of cancers. LKB1 directly binds and activates its downstream kinases including the AMP-activated protein kinase (AMPK) and AMPK-related kinases by phosphorylation, which has been intensively investigated for the past decades. An increasing number of studies has uncovered the posttranslational modifications (PTMs) of LKB1 and consequent changes in its localization, activity, and interaction with substrates. The alteration in LKB1 function as a consequence of genetic mutations and aberrant upstream signaling regulation leads to tumor development and progression. Here, we review current knowledge about the mechanism of LKB1 in cancer and the contributions of PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, prenylation, and others, to the regulation of LKB1 function, offering new insights into the therapeutic strategies in cancer.

The role of CaMKK2 in Golgi-associated vesicle trafficking

Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is a serine/threonine-protein kinase, that is involved in maintaining various physiological and cellular processes within the cell that regulate energy homeostasis and cell growth. CaMKK2 regulates glucose metabolism by the activation of downstream kinases, AMP-activated protein kinase (AMPK) and other calcium/calmodulin-dependent protein kinases. Consequently, its deregulation has a role in multiple human metabolic diseases including obesity and cancer. Despite the importance of CaMKK2, its signalling pathways and pathological mechanisms are not completely understood. Recent work has been aimed at broadening our understanding of the biological functions of CaMKK2. These studies have uncovered new interaction partners that have led to the description of new functions that include lipogenesis and Golgi vesicle trafficking. Here, we review recent insights into the role of CaMKK2 in membrane trafficking mechanisms and discuss the functional implications in a cellular context and for disease.

FAT4 activation inhibits epithelial-mesenchymal transition (EMT) by promoting autophagy in H2228/Cer cells

As a tumor suppressor in lung cancer, FAT atypical cadherin 4 (FAT4) has a critical role in epithelial-mesenchymal transition (EMT). However, the role of FAT4 in ceritinib-resistant anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC) EMT has not been reported. It is necessary to discuss the role of FAT4 in this process and its potential mechanism of interaction. We found that the expression level of FAT4 was downregulated markedly in ceritinib-resistant NCI-H2228 (H2228/Cer) cells. Jujuboside A, a FAT4 activator, diminished EMT and metastasis of H2228/Cer cells. Importantly, autophagy inhibition inverted the inhibitory effect of FAT4 activation on EMT. Furthermore, we found the regulatory action of FAT4 on autophagy was related to proteasome 26S subunit ubiquitin receptor and non-ATPase 4 (PSMD4) and proteasome 20S subunit beta 4 (PSMB4), and the inhibitory effect of autophagy on EMT might be related to ROS/NF-κB/IκB-α and Wnt/β-catenin pathways. In conclusion, FAT4 activation can inhibit the process of EMT in H2228/Cer cells by promoting autophagy, which provides a potential target for ceritinib-resistant ALK positive NSCLC therapy.