Silencing PFKP inhibits starvation-induced autophagy, glycolysis, and epithelial mesenchymal transition in oral squamous cell carcinoma

Glycolysis, the sweet appetite of the tumor microenvironment

Cancer cells display an altered metabolic phenotype, characterised by increased glycolysis and lactate production, even in the presence of sufficient oxygen - a phenomenon known as the Warburg effect. This metabolic reprogramming is a crucial adaptation that enables cancer cells to meet their elevated energy and biosynthetic demands. Importantly, the tumor microenvironment plays a pivotal role in shaping and sustaining this metabolic shift in cancer cells. This review explores the intricate relationship between the tumor microenvironment and the Warburg effect, highlighting how communication within this niche regulates cancer cell metabolism and impacts tumor progression and therapeutic resistance. We discuss the potential of targeting the Warburg effect as a promising therapeutic strategy, with the aim of disrupting the metabolic advantage of cancer cells and enhancing our understanding of this complex interplay within the tumor microenvironment.

Lactylome analyses suggest systematic lysine-lactylated substrates in oral squamous cell carcinoma under normoxia and hypoxia

Cancer cells tend to live in hypoxic environment characterized by enhanced glycolysis and accumulation of lactate. Intracellular lactate is shown to drive a novel type of post-translational modification (PTM), lysine lactylation (Kla). Kla has been confirmed to affect the malignant progression of tumors such as hepatocellular carcinoma (HCC) and colon cancer, whereas the global lactylomic profiling of oral squamous cell carcinoma (OSCC) is unclear. Here, the integrative lactylome and proteome analyses by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified 1011 Kla sites within 532 proteins and 1197 Kla sites within 608 proteins in SCC25 cells under normoxic and hypoxic environments, respectively. Among these lactylated proteins, histones accounted for only a small fraction, suggesting the presence of Kla modification of OSCC in a large number of non-histone proteins. Notably, Kla preferred to enrich in spliceosome, ribosome and glycolysis/gluconeogenesis pathway in both normoxic and hypoxic cultures. Compared with normoxia, 589 differential proteins with 898 differentially lactylated sites were detected under hypoxia, which were mainly associated with the glycolysis/gluconeogenesis pathway by KEGG analysis. Importantly, we verified the presence of lactylation modification in the spliceosomal proteins hnRNPA1, SF3A1, hnRNPU and SLU7, as well as in glycolytic enzyme PFKP. In addition, the differential alternative splicing analysis described the divergence of pre-mRNA splicing patterns in the presence or absence of sodium lactate and at different oxygen concentrations. Finally, a negative correlation between tissue Kla levels and the prognosis of OSCC patients was revealed by immunohistochemistry. Our study is the first report to elucidate the lactylome and its biological function in OSCC, which deepens our understanding of the mechanisms underlying OSCC progression and provides a novel strategy for targeted therapy for OSCC.

A positive feedback loop between PFKP and c-Myc drives head and neck squamous cell carcinoma progression

BACKGROUND

The aberrant expression of phosphofructokinase-platelet (PFKP) plays a crucial role in the development of various human cancers by modifying diverse biological functions. However, the precise molecular mechanisms underlying the role of PFKP in head and neck squamous cell carcinoma (HNSCC) are not fully elucidated.

METHODS

We assessed the expression levels of PFKP and c-Myc in tumor and adjacent normal tissues from 120 HNSCC patients. A series of in vitro and in vivo experiments were performed to explore the impact of the feedback loop between PFKP and c-Myc on HNSCC progression. Additionally, we explored the therapeutic effects of targeting PFKP and c-Myc in HNSCC using Patient-Derived Organoids (PDO), Cell Line-Derived Xenografts, and Patients-Derived Xenografts.

RESULTS

Our findings indicated that PFKP is frequently upregulated in HNSCC tissues and cell lines, correlating with poor prognosis. Our in vitro and in vivo experiments demonstrate that elevated PFKP facilitates cell proliferation, angiogenesis, and metastasis in HNSCC. Mechanistically, PFKP increases the ERK-mediated stability of c-Myc, thereby driving progression of HNSCC. Moreover, c-Myc stimulates PFKP expression at the transcriptional level, thus forming a positive feedback loop between PFKP and c-Myc. Additionally, our multiple models demonstrate that co-targeting PFKP and c-Myc triggers synergistic anti-tumor effects in HNSCC.

CONCLUSION

Our study demonstrates the critical role of the PFKP/c-Myc positive feedback loop in driving HNSCC progression and suggests that simultaneously targeting PFKP and c-Myc may be a novel and effective therapeutic strategy for HNSCC.

No energy, no autophagy-Mechanisms and therapeutic implications of autophagic response energy requirements

Autophagy is a lysosome-mediated self-degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often-overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP-consuming autophagic events, including transcription/translation/interaction of autophagy-related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy-dependent fine-tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed.

A partial epithelial-mesenchymal transition signature for highly aggressive colorectal cancer cells that survive under nutrient restriction

Partial epithelial-mesenchymal transition (p-EMT) has recently been identified as a hybrid state consisting of cells with both epithelial and mesenchymal characteristics and is associated with the migration, metastasis, and chemoresistance of cancer cells. Here, we describe the induction of p-EMT in starved colorectal cancer (CRC) cells and identify a p-EMT gene signature that can predict prognosis. Functional characterisation of starvation-induced p-EMT in HCT116, DLD1, and HT29 cells showed changes in proliferation, morphology, and drug sensitivity, supported by in vivo studies using the chorioallantoic membrane model. An EMT-specific quantitative polymerase chain reaction (qPCR) array was used to screen for deregulated genes, leading to the establishment of an in silico gene signature that was correlated with poor disease-free survival in CRC patients along with the CRC consensus molecular subtype CMS4. Among the significantly deregulated p-EMT genes, a triple-gene signature consisting of SERPINE1, SOX10, and epidermal growth factor receptor (EGFR) was identified. Starvation-induced p-EMT was characterised by increased migratory potential and chemoresistance, as well as E-cadherin processing and internalisation. Both gene signature and E-cadherin alterations could be reversed by the proteasomal inhibitor MG132. Spatially resolving EGFR expression with high-resolution immunofluorescence imaging identified a proliferation stop in starved CRC cells caused by EGFR internalisation. In conclusion, we have gained insight into a previously undiscovered EMT mechanism that may become relevant when tumour cells are under nutrient stress, as seen in early stages of metastasis. Targeting this process of tumour cell dissemination might help to prevent EMT and overcome drug resistance. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Inhibition of autophagy initiation: A novel strategy for oral squamous cell carcinomas

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most common forms of oral cancer and is known to have poor prognostic outcomes. Autophagy is known to be associated with aggressive tumor biology of OSCC. Hence, this study aimed to develop a novel therapeutic strategy against OSCC by targeting the autophagic pathway.

METHODS

Immunoblotting, and confocal microscopy were used to examine the effect of tumor microenvironmental stressors on the autophagy activity. Cellular proliferation and migration assays were performed to assess the anti-cancer activity of standard chemotherapy and autophagy initiation inhibitors, either alone or in combination. High resolution mass-spectrometry based proteomic analysis was utilized to understand the mechanisms behind chemoresistance in OSCC models. Finally, immunohistochemistry was performed to determine associations between autophagy markers and clinicopathological characteristics.

RESULTS

Tumor microenvironmental stressors were shown to induce autophagy activity in OSCC cell lines. Novel combinations of chemotherapy and autophagy inhibitors as well as different classes of autophagy inhibitors were identified. Combination of MRT68921 and SAR405 demonstrated marked synergy in their anti-proliferative activity and also showed synergy with chemotherapy in chemoresistant OSCC cell models. Autophagy was identified as one of the key pathways involved in mediating chemoresistance in OSCC. Furthermore, TGM2 was identified as a key upstream regulator of chemoresistance in OSCC models. Finally, positive staining for autophagosome marker LC3 was shown to be associated with low histological grade OSCC.

CONCLUSION

In conclusion, this study identified a combination of novel autophagy inhibitors which can potently inhibit proliferation of both chemosensitive as well as chemoresistant OSCC cells and could be developed as a novel therapy against advanced OSCC tumors.

Unveiling the Potential of Serum MiR-483-5p: A Promising Diagnostic and Prognostic Biomarker in OLP and OSCC Patients by In silico Analysis of Differential Gene Expression

BACKGROUND

Oral squamous cell carcinoma (OSCC) and oral lichen planus (OLP) are two separate conditions affecting the mouth and result in varying clinical outcomes and levels of malignancy. Achieving early diagnosis and effective therapy planning requires the identification of reliable diagnostic biomarkers for these disorders. MicroRNAs (miRNAs) have recently received attention as powerful biomarkers for various illnesses, including cancer. In particular, miR-483-5p is a promising diagnostic and prognostic biomarker in various cancers. Therefore, this study aimed to investigate the role of serum miR-483-5p in the diagnosis and prognosis of OLP and OSCC patients by in silico analysis of differential gene expression.

METHODS

GSE23558 and GSE52130 data sets were selected, and differential gene expression analysis was performed using microarray data from GSE52130 and GSE23558. The analysis focused on comparing OLP and OSCC samples with normal samples. The genes intersected through the differential gene expression analysis were then extracted to determine the overlapping genes among the upregulated or downregulated DEGs. The downregulated genes among the DEGs were subsequently imported into the miRWalk database to search for potential target genes of miRNA 483-5p that lacked validation. To gain insight into the biological pathways associated with the DEGs, we conducted pathway analysis utilizing tools, such as Enrichr. Additionally, the cellular components associated with these DEGs were investigated by analyzing the String database. On the other hand, blood serum samples were collected from 35 OSCC patients, 34 OLP patients, and 34 healthy volunteers. The expression level of miR-483-5p was determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR). The Kruskal-Wallis test was utilized to investigate the considerable correlation. Moreover, this study explored the prognostic value of miR-483-5p through its association with clinicopathological parameters in OSCC patients.

RESULTS

The results showed that serum expression of miR-483-5p was considerably higher in OSCC patients compared to OLP patients and healthy controls (p 0.0001) and that this difference was statistically significant. Furthermore, elevated miR-483-5p expression was associated with tumor size, lymph node metastasis, and stage of tumor nodal metastasis in OSCC patients (p 0.001, p 0.038, and p 0.0001, respectively). In silico analysis found 71 upregulated genes at the intersection of upregulated DEGs and 44 downregulated genes at the intersection of downregulated DEGs, offering insight into the potential underlying mechanisms of miR-483-5p's engagement in OSCC and OLP. The majority of these DEGs were found to be involved in autophagy pathways, but DEGs involved in the histidine metabolism pathway showed significant results. Most of these DEGs were located in the extracellular region. After screening for downregulated genes that were invalidated, miRNA 483-5p had 7 target genes.

CONCLUSION

This study demonstrates the potential of serum miR-483-5p as a promising diagnostic and prognostic biomarker in OSCC and OLP patients. Its upregulation in OSCC patients and its association with advanced tumor stage and potential metastasis suggest the involvement of miR-483-5p in critical signaling pathways involved in cell proliferation, apoptosis, and cell cycle regulation, making it a reliable indicator of disease progression. Nevertheless, additional experimental studies are essential to validate these findings and establish a foundation for the advancement of targeted therapies and personalized treatment approaches.

PFKP is upregulated in 5-fluorouracil-resistant patients and suppresses the antitumor activity of 5-fluorouracil in colorectal cancer in vitro and in vivo

As a long-established chemotherapy drug, 5-fluorouracil (5-FU) is widely used to clinically manage colorectal cancer (CRC). However, a substantial portion of patients develop 5-FU resistance at some stage, which poses a great challenge. Therefore, revealing the mechanisms that could guide the development of effective strategies to overcome 5-FU resistance is required. Here, we report that the expression of PFKP was higher in HCT116/5-FU CRC. Furthermore, genetic suppression of PFKP suppresses glycolysis, NF-κB activation, and expression of GLUT1 and HK2 in HCT116/5-FU cells. PFKP overexpression promotes glycolysis and expression of GLUT1 and HK2 via the NF-κB signaling pathway in HCT116 cells. Our functional assays demonstrated that PFKP silencing could sensitize HCT116/5-FU cells to 5-FU with an elevated population of apoptotic cells. In contrast, forced expression of PFKP conferred 5-FU resistance in HCT116 cells. Furthermore, PFKP silencing significantly inhibited CRC xenograft tumor growth. Notably, the combination of PFKP silencing and 5-FU inhibited tumor growth. Therefore, our results demonstrated that PFKP enhances 5-FU resistance by promoting glycolysis, indicating that PFKP could be a novel candidate for targeted therapy for 5-FU-resistant CRC.

PFKP is a prospective prognostic, diagnostic, immunological and drug sensitivity predictor across pan-cancer

Phosphofructokinase, platelet (PFKP) is a rate-limiting enzyme of glycolysis that plays a decisive role in various human physio-pathological processes. PFKP has been reported to have multiple functions in different cancer types, including lung cancer and breast cancer. However, no systematic pancancer analysis of PFKP has been performed; this type of analysis could elucidate the clinical value of PFKP in terms of diagnosis, prognosis, drug sensitivity, and immunological correlation. Systematic bioinformation analysis of PFKP was performed based on several public datasets, including The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), Genotype-Tissue Expression Project (GTEx), and Human Protein Atlas (HPA). Prospective carcinogenesis of PFKP across cancers was estimated by expression analysis, effect on patient prognosis, diagnosis significance evaluation, and immunity regulation estimation. Then, pancancer functional enrichment of PFKP was also assessed through its effect on the signaling score and gene expression profile. Finally, upstream expression regulation of PFKP was explored by promoter DNA methylation and transcription factor (TF) prediction. Our analysis revealed that high expression of PFKP was found in most cancer types. Additionally, a high level of PFKP displayed a significant correlation with poor prognosis in patients across cancers. The diagnostic value of PFKP was performed based on its positive correlation with programmed cell death-ligand 1 (PD-L1). We also found an obvious immune-regulating effect of PFKP in most cancer types. PFKP also had a strong negative correlation with several cancer drugs. Finally, ectopic expression of PFKP may depend on DNA methylation and several predicated transcription factors, including the KLF (KLF transcription factor) and Sp (Sp transcription factor) families. This pancancer analysis revealed that a high expression level of PFKP might be a useful biomarker and predictor in most cancer types. Additionally, the performance of PFKP across cancers also suggested its meaningful role in cancer immunity regulation, even in immunotherapy and drug resistance. Overall, PFKP might be explored as an auxiliary monitor for pancancer early prognosis and diagnosis.

PFKP: More than phosphofructokinase

Phosphofructokinase (PFK) is one of the key enzymes that functions in glycolysis. Studies show that PFKP regulates cell proliferation, apoptosis, autophagy, cell migration/metastasis, and stemness through glycolysis and glycolysis-independent functions. PFKP performs its function not only in the cytoplasm, but also at the cell membrane, on the mitochondria, at the lysosomal membrane, and in the nucleus. The functions of PFKP are extensively studied in cancer cells. PFKP is also highly expressed in certain immune cells; nevertheless, the study of the PFKP's role in immune cells is limited. In this review, we summarize how the expression and activity of PFKP are regulated in cancer cells. PFKP may be applied as a prognostic marker due to its overexpression and significant functions in cancer cells. As such, specifically targeting/inhibiting PFKP may be a critical and promising strategy for cancer therapy.

Quantitative proteomic analysis uncovers protein-expression profiles during gonadotropin-dependent folliculogenesis in mice†

Ovarian follicle is the basic functional unit of female reproduction, and is composed of oocyte and surrounding granulosa cells. In mammals, folliculogenesis strictly rely on gonadotropin regulations to determine the ovulation and the quality of eggs. However, the dynamic changes of protein-expressing profiles in follicles at different developmental stages remain largely unknown. By performing mass-spectrometry-based quantitative proteomic analysis of mouse follicles, we provide a proteomic database (~3000 proteins) that covers three key stages of gonadotropin-dependent folliculogenesis. By combining bioinformatics analysis with in situ expression validation, we showed that our proteomic data well reflected physiological changes during folliculogenesis, which provided potential to predict unknown regulators of folliculogenesis. Additionally, by using the oocyte structural protein zona pellucida protein 2 as the internal control, we showed the possibility of our database to predict the expression dynamics of oocyte-expressing proteins during folliculogenesis. Taken together, we provide a high-coverage proteomic database to study protein-expression dynamics during gonadotropin-dependent folliculogenesis in mammals.

Glycolysis regulator PFKP induces human melanoma cell proliferation and tumor growth

PURPOSE

Cutaneous melanoma is an aggressive and deadly cancer resulting from malignant transformation of cells involved in skin pigmentation. Glycolysis is widely implicated in cancer progression, but its precise role in melanoma has not been extensively studied. Here, we investigated the role of the glycolysis regulator phosphofructokinase 1 platelet isoform (PFKP) in melanoma progression.

METHODS

PFKP expression in human melanoma tissues was analyzed by immunohistochemistry. Knockdown of PFKP by siRNA and overexpression of PFKP were performed to evaluate its functions in vitro. CCK-8 assay was used to assess cell proliferation. Glycolytic activity was determined via measurement of extracellular acidification rate (ECAR), lactic acid level, and ATP content. A tumor xenograft model was used to test the function of PFKP in vivo.

RESULTS

PFKP upregulation was observed in human melanoma tissues and correlated with poor patient survival. Knockdown of PFKP in human melanoma cells suppressed cell proliferation and reduced ECAR, ATP levels, and lactic acid levels, while overexpression of PFKP displayed the opposite effects. In vivo, knockdown of PFKP in melanoma cells markedly reduced tumorigenesis. Inhibitory effects on cell proliferation, glycolysis, and tumorigenesis due to PFKP knockdown were further augmented upon treatment with the glycolysis inhibitor 2-deoxy-D-glucose (2-DG).

CONCLUSION

Collectively, these results indicate that PFKP expression in melanoma cells increases proliferation and glycolytic activity in vitro and promotes tumorigenesis in vivo, suggesting that suppression of PKFP and inhibition of glycolysis may potently suppress melanoma progression.

Autophagy and Glycometabolic Reprograming in the Malignant Progression of Lung Cancer: A Review

Lung cancer is one of the leading causes of cancer-related deaths worldwide. However, there are currently limited treatment options that are widely available to patients with advanced lung cancer, and further research is required to inhibit or reverse disease progression more effectively. In lung and other solid tumor cancers, autophagy and glycometabolic reprograming are critical regulators of malignant development, including proliferation, drug resistance, invasion, and metastasis. To provide a theoretical basis for therapeutic strategies targeting autophagy and glycometabolic reprograming to prevent lung cancer, we review how autophagy and glycometabolism are regulated in the malignant development of lung cancer based on research progress in other solid tumors.

Construction and validation of a metabolic-related genes prognostic model for oral squamous cell carcinoma based on bioinformatics

BACKGROUND

Oral squamous cell carcinoma (OSCC) accounts for a frequently-occurring head and neck cancer, which is characterized by high rates of morbidity and mortality. Metabolism-related genes (MRGs) show close association with OSCC development, metastasis and progression, so we constructed an MRGs-based OSCC prognosis model for evaluating OSCC prognostic outcome.

METHODS

This work obtained gene expression profile as well as the relevant clinical information from the The Cancer Genome Atlas (TCGA) database, determined the MRGs related to OSCC by difference analysis, screened the prognosis-related MRGs by performing univariate Cox analysis, and used such identified MRGs for constructing the OSCC prognosis prediction model through Lasso-Cox regression. Besides, we validated the model with the GSE41613 dataset based on Gene Expression Omnibus (GEO) database.

RESULTS

The present work screened 317 differentially expressed MRGs from the database, identified 12 OSCC prognostic MRGs through univariate Cox regression, and then established a clinical prognostic model composed of 11 MRGs by Lasso-Cox analysis. Based on the optimal risk score threshold, cases were classified as low- or high-risk group. As suggested by Kaplan-Meier (KM) analysis, survival rate was obviously different between the two groups in the TCGA training set (P < 0.001). According to subsequent univariate and multivariate Cox regression, risk score served as the factor to predict prognosis relative to additional clinical features (P < 0.001). Besides, area under ROC curve (AUC) values for patient survival at 1, 3 and 5 years were determined as 0.63, 0.70, and 0.76, separately, indicating that the prognostic model has good predictive accuracy. Then, we validated this clinical prognostic model using GSE41613. To enhance our model prediction accuracy, age, gender, risk score together with TNM stage were incorporated in a nomogram. As indicated by results of ROC curve and calibration curve analyses, the as-constructed nomogram had enhanced prediction accuracy compared with clinicopathological features alone, besides, combining clinicopathological characteristics with risk score contributed to predicting patient prognosis and guiding clinical decision-making.

CONCLUSION

In this study, 11 MRGs prognostic models based on TCGA database showed superior predictive performance and had a certain clinical application prospect in guiding individualized.

Identification and validation of a novel tumor driver gene signature for diagnosis and prognosis of head and neck squamous cell carcinoma

Objective: Head and neck squamous cell carcinoma (HNSCC) is a common heterogeneous cancer with complex carcinogenic factors. However, the current TNM staging criteria to judge its severity to formulate treatment plans and evaluate the prognosis are particularly weak. Therefore, a robust diagnostic model capable of accurately diagnosing and predicting HNSCC should be established. Methods: Gene expression and clinical data were retrieved from The Cancer Genome Atlas and Gene Expression Omnibus databases. Key prognostic genes associated with HNSCC were screened with the weighted gene co-expression network analysis and least absolute shrinkage and selection operator (LASSO) Cox regression model analysis. We used the timeROC and survival R packages to conduct time-dependent receiver operating characteristic curve analyses and calculated the area under the curve at different time points of model prediction. Patients in the training and validation groups were divided into high- and low-risk subgroups, and Kaplan-Meier (K-M) survival curves were plotted for all subgroups. Subsequently, LASSO and support vector machine algorithms were used to screen genes to construct diagnostic model. Furthermore, we used the Wilcoxon signed-rank test to compare the half-maximal inhibitory concentrations of common chemotherapy drugs among patients in different risk groups. Finally, the expression levels of eight genes were measured using quantitative real-time polymerase chain reaction and immunohistochemistry. Results: Ten genes (SSB, PFKP, NAT10, PCDH9, SHANK2, PAX8, CELSR3, DCLRE1C, MAP2K7, and ODF4) with prognostic potential were identified, and a risk score was derived accordingly. Patients were divided into high- and low-risk groups based on the median risk score. The K-M survival curves confirmed that patients with high scores had significantly worse overall survival. Receiver operating characteristic curves proved that the prognostic signature had good sensitivity and specificity for predicting the prognosis of patients with HNSCC. Univariate and multivariate Cox regression analyses confirmed that the gene signature was an independent prognostic risk factor for HNSCC. Diagnostic model was built by identifying eight genes (SSB, PFKP, NAT10, PCDH9, CELSR3, DCLRE1C, MAP2K7, and ODF4). The high-risk group showed higher sensitivity to various common chemotherapeutic drugs. DCLRE1C expression was higher in normal tissues than in HNSCC tissues. Conclusion: Our study identified the important role of tumor-driver genes in HNSCC and their potential clinical diagnostic and prognostic values to facilitate individualized management of patients with 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.

PFKP and GPC6 Variants Were Correlated with Alcohol-Induced Femoral Head Necrosis Risk in the Chinese Han Population

Background

Osteonecrosis of the femoral head (ONFH) is a common joint disease caused by excessive drinking, genetic factors, etc. The purpose of this study was to investigate the association between PFKP and GPC6 variants and alcohol-induced ONFH (AIONFH) risk in the Chinese Han population.

Methods

This study genotyped 9 selected single nucleotide polymorphisms (SNPs) in 402 males by Agena MassARRAY Assay. By calculating odds ratios (ORs) and 95% confidence intervals (CIs), we assessed the effect of gene polymorphisms on AIONFH occurrence. False-positive report probability (FPRP) analysis and power were also used to evaluate the significant results. Multifactor dimensionality reduction (MDR) software was also utilized to predict the association between the selected SNPs and AIONFH risk.

Results

The overall analysis showed that PFKP rs10903966 and GPC6 rs7320969 were correlated with AIONFH risk. GPC6 rs4773724 was associated with a reduced risk of AIONFH, while individuals with GPC6 rs9523981 CC genotype had a higher risk of AIONFH than individuals with the other genotypes among people under 42 years old. Based on stratified analysis of necrotic sites, rs7320969 was related to a decreased risk of AIONFH, while rs10903966 and rs9523981 were related to an increased risk of AIONFH. In addition, rs1008993 and rs7320969 were observed to be linked to AIONFH risk in patients at different clinical stages. Meanwhile, there were significant differences in TC, TG, platelet, ApoA1 and ApoB levels among subjects with different genotypes of rs1008993, rs9523981, rs7320969 and rs59624626. The results of MDR showed that rs11251720 and rs7320969 may play a synergistic role in predicting the risk of AIONFH.

Conclusion

PFKP rs10903966 and GPC6 rs9523981 were associated with an increased risk of AIONFH, while GPC6 (rs7320969 and rs4773724) were correlated with a decreased risk of AIONFH. This result will need further experiments to verify.

Ubiquitinating the way to T cell metabolism

In this issue, Harris et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202203095) show that phosphofructokinase is a substrate for ubiquitination by Fbxo7, a key protein in the ubiquitination pathway. Their findings point to a new interplay between metabolic enzyme degradation in the regulation of T cells.

Essential role of aerobic glycolysis in epithelial-to-mesenchymal transition during carcinogenesis

Epithelial-to-mesenchymal transition (EMT) confers the most lethal characteristics to cancer cells i.e., metastasis and resistance to chemo-and-radio-therapy, and therefore exhibit an appealing target in the field of oncology. Research in the past decade has demonstrated the crucial role of aerobic glycolysis in EMT, which is generally credited as the glucose metabolism for the creation of biomass such as fatty acids, amino acids, and nucleotides thereby providing building blocks for limitless proliferation. In the present review, apart from discussing EMT's evident role in the metastatic process and cancer stemness, we also talked about the vital role of glycolytic enzymes viz. GLUTs, HKs, PGI, PFK-1, aldolase, enolase, PK, LDHA, etc. in the induction of the EMT process in cancerous cells.

Riboflavin deficiency leads to irreversible cellular changes in the RPE and disrupts retinal function through alterations in cellular metabolic homeostasis

Ariboflavinosis is a pathological condition occurring as a result of riboflavin deficiency. This condition is treatable if detected early enough, but it lacks timely diagnosis. Critical symptoms of ariboflavinosis include neurological and visual manifestations, yet the effects of flavin deficiency on the retina are not well investigated. Here, using a diet induced mouse model of riboflavin deficiency, we provide the first evidence of how retinal function and metabolism are closely intertwined with riboflavin homeostasis. We find that diet induced riboflavin deficiency causes severe decreases in retinal function accompanied by structural changes in the neural retina and retinal pigment epithelium (RPE). This is preceded by increased signs of cellular oxidative stress and metabolic disorder, in particular dysregulation in lipid metabolism, which is essential for both photoreceptors and the RPE. Though many of these deleterious phenotypes can be ameliorated by riboflavin supplementation, our data suggests that some patients may continue to suffer from multiple pathologies at later ages. These studies provide an essential cellular and mechanistic foundation linking defects in cellular flavin levels with the manifestation of functional deficiencies in the visual system and paves the way for a more in-depth understanding of the cellular consequences of ariboflavinosis.

Introduction of mutant TP53 related genes in metabolic pathways and evaluation their correlation with immune cells, drug resistance and sensitivity

BACKGROUND

Although the relationship between TP53 mutation, TP53 metabolism pathways, and tumorigenesis has been investigated, pan-cancer analysis of TP53 mutations and related metabolism pathways is not completely available in common types of human cancers. Thus, this study was going to represent TP53 mutant-related metabolism genes and pathways in a pan-cancer study and investigate the relationship between selected genes and drug resistance.

METHODS

The DNA-seq data, RNA-seq data, and clinical information of 12 types of cancer were downloaded from the cancer genome atlas (TCGA) database. GSE70479 data were obtained from GEO database for validation of our TCGA data. To evaluate the survival rate of patients, GEPIA2 was applied. The CCLE and GDSC database were used to investigate drug resistance and sensitivity.

RESULTS

Our findings indicated that TTN, MUC16, and TP53 were present in 12 types of cancer with high level of mutation frequency which abundance of TP53 mutations was higher. Mutant TP53-related (mTP53) pathways and genes including PKM, SLC16A3, HK2, PFKP, PHGDH, and CTSC were obtained from enrichment analysis and interestingly, top pathways were associated with metabolism including glycolysis and mTORC1 pathway. Our results showed the expression of some candidate genes correlated with immune markers, prognosis, and drug resistance.

CONCLUSIONS

Top mutant genes for 12 cancers were highlighted while TP53 was selected as top mutant gene, and metabolic genes associated with the TP53 mutation were identified that some of which are important in poor prognosis. In doing so, mutations in TP53 could run some metabolic pathways and drug resistance and sensitivity.

Characterization of phosphofructokinase (PFK) from mud crab Scylla paramamosain and its role in mud crab dicistrovirus-1 proliferation

Phosphofructokinase (PFK), the key enzyme of glycolysis, can catalyze the irreversible transphosphorylation of fructose-6-phosphate forming fructose-1, 6-biphosphate. In the present study, a PFK gene from the mud crab Scylla paramamosain, named SpPFK, was cloned and characterized. The full length of SpPFK contained a 5'untranslated region (UTR) of 249 bp, an open reading frame of 2,859 bp, and a 3'UTR of 1,248 bp. The mRNA of SpPFK was highly expressed in the gill, followed by the hemocytes and muscle. The expression of SpPFK was significantly up-regulated after mud crab dicistrovirus-1 (MCDV-1) infection. Knocking down SpPFK in vivo by RNA interference significantly reduced the expression of lactate dehydrogenase after MCDV-1 infection. Furthermore, silencing of SpPFK in vivo increased the survival rate of mud crabs and decreased the MCDV-1 copies in the gill and hepatopancreas after MCDV-1 infection. All these results suggested that SpPFK could play an important role in the process of MCDV-1 proliferation in mud crab.

Tumor Cell Glycolysis—At the Crossroad of Epithelial–Mesenchymal Transition and Autophagy

Upregulation of glycolysis, induction of epithelial–mesenchymal transition (EMT) and macroautophagy (hereafter autophagy), are phenotypic changes that occur in tumor cells, in response to similar stimuli, either tumor cell-autonomous or from the tumor microenvironment. Available evidence, herein reviewed, suggests that glycolysis can play a causative role in the induction of EMT and autophagy in tumor cells. Thus, glycolysis has been shown to induce EMT and either induce or inhibit autophagy. Glycolysis-induced autophagy occurs both in the presence (glucose starvation) or absence (glucose sufficiency) of metabolic stress. In order to explain these, in part, contradictory experimental observations, we propose that in the presence of stimuli, tumor cells respond by upregulating glycolysis, which will then induce EMT and inhibit autophagy. In the presence of stimuli and glucose starvation, upregulated glycolysis leads to adenosine monophosphate-activated protein kinase (AMPK) activation and autophagy induction. In the presence of stimuli and glucose sufficiency, upregulated glycolytic enzymes (e.g., aldolase or glyceraldehyde 3-phosphate dehydrogenase) or decreased levels of glycolytic metabolites (e.g., dihydroxyacetone phosphate) may mimic a situation of metabolic stress (herein referred to as “pseudostarvation”), leading, directly or indirectly, to AMPK activation and autophagy induction. We also discuss possible mechanisms, whereby glycolysis can induce a mixed mesenchymal/autophagic phenotype in tumor cells. Subsequently, we address unresolved problems in this field and possible therapeutic consequences.

Fructose-1,6-bisphosphatase 2 represses cervical cancer progression via inhibiting aerobic glycolysis through promoting pyruvate kinase isozyme type M2 ubiquitination

Growing evidence has shown that aerobic glycolysis, as a hallmark of cancer cells, plays a crucial role in cervical cancer. The aim of the study is to uncover whether fructose-1,6-bisphosphatase 2 (FBP2) is involved in cervical cancer progression via the aerobic glycolysis pathway. FBP2 levels were determined by quantitative PCR (qPCR) and western blotting. Cell growth viability and apoptosis were tested by cell counting kit-8 (CCK-8) and flow cytometry assays. Immunoprecipitation assay was applied for the detection of the FBP2 effect on pyruvate kinase isozyme type M2 (PKM2) ubiquitination. FBP2 level was decreased in cervical cancer, which is closely linked to shorter overall survival. FBP2 decreased cell growth and aerobic glycolysis and increased cell apoptosis, as well as decreased PKM2 expression and increased its ubiquitination level. The above-mentioned roles of FBP2 were weakened followed by PKM2 overexpression. FBP2 inhibited cervical cancer cell growth via inhibiting aerobic glycolysis by inducing PKM2 ubiquitination.

A Starvation-Based 9-mRNA Signature Correlates With Prognosis in Patients With Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the world’s most prevalent and lethal cancers. Notably, the microenvironment of tumor starvation is closely related to cancer malignancy. Our study constructed a signature of starvation-related genes to predict the prognosis of liver cancer patients.

Methods

The mRNA expression matrix and corresponding clinical information of HCC patients were obtained from the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). Gene set enrichment analysis (GSEA) was used to distinguish different genes in the hunger metabolism gene in liver cancer and adjacent tissues. Gene Set Enrichment Analysis (GSEA) was used to identify biological differences between high- and low-risk samples. Univariate and multivariate analyses were used to construct prognostic models for hunger-related genes. Kaplan-Meier (KM) and receiver-operating characteristic (ROC) were used to assess the model accuracy. The model and relevant clinical information were used to construct a nomogram, protein expression was detected by western blot (WB), and transwell assay was used to evaluate the invasive and metastatic ability of cells.

Results

First, we used univariate analysis to identify 35 prognostic genes, which were further demonstrated to be associated with starvation metabolism through Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). We then used multivariate analysis to build a model with nine genes. Finally, we divided the sample into low- and high-risk groups according to the median of the risk score. KM can be used to conclude that the prognosis of high- and low-risk samples is significantly different, and the prognosis of high-risk samples is worse. The prognostic accuracy of the 9-mRNA signature was also tested in the validation data set. GSEA was used to identify typical pathways and biological processes related to 9-mRNA, cell cycle, hypoxia, p53 pathway, and PI3K/AKT/mTOR pathway, as well as biological processes related to the model. As evidenced by WB, EIF2S1 expression was increased after starvation. Overall, EIF2S1 plays an important role in the invasion and metastasis of liver cancer.

Conclusions

The 9-mRNA model can serve as an accurate signature to predict the prognosis of liver cancer patients. However, its mechanism of action warrants further investigation.

The two faces of autophagy in oral squamous cell carcinoma

OBJECTIVE

To undertake a comprehensive review of the current knowledge and understanding of autophagy in oral squamous cell carcinoma (OSCC), focusing on putative roles in tumour suppression and survival along with the influence of this cell death pathway on the development of resistance to chemotherapeutic treatment.

DESIGN

Several well utilised databases (PubMed, Medline, Google Scholar) were searched for the relevant literature using terms and keywords including but not limited too; autophagy and cancer, autophagy and OSCC, tumour survival, autophagy and oral microbiome, autophagy immunogenicity, OSCC chemoresistance.

RESULTS

Up-regulation of autophagy has been shown to promote tumour cell survival in the tumour microenvironment while in healthy cells, autophagy induction acts to prevent severe DNA mutations that can lead to cancer. Cancers utilise the autophagy pathway to promote survival during the stress of chemotherapeutic treatment and can induce resistance to chemotherapeutic drugs CONCLUSION: The ambiguous role of autophagy within cancers is still problematic in clinical fields. Within OSCC understanding whether autophagy plays a preventive or causative role is essential and may be beneficial in determining how modulation of this pathway may impact on OSSC and oral cancer patients.

Starvation induced autophagy promotes the progression of bladder cancer by LDHA mediated metabolic reprogramming

Background

Aberrant autophagy and preternatural elevated glycolysis are prevalent in bladder cancer (BLCA) and are both related to malignant progression. However, the regulatory relationship between autophagy and glycolytic metabolism remains largely unknown. We imitated starvation conditions in the tumour microenvironment and found significantly increased levels of autophagy and aerobic glycolysis, which both regulated the progression of BLCA cells. We further explored the regulatory relationships and mechanisms between them.

Methods

We used immunoblotting, immunofluorescence and transmission electron microscopy to detect autophagy levels in BLCA cells under different treatments. Lactate and glucose concentration detection demonstrated changes in glycolysis. The expression of lactate dehydrogenase A (LDHA) was detected at the transcriptional and translational levels and was also silenced by small interfering RNA, and the effects on malignant progression were further tested. The underlying mechanisms of signalling pathways were evaluated by western blot, immunofluorescence and immunoprecipitation assays.

Results

Starvation induced autophagy, regulated glycolysis by upregulating the expression of LDHA and caused progressive changes in BLCA cells. Mechanistically, after starvation, the ubiquitination modification of Axin1 increased, and Axin1 combined with P62 was further degraded by the autophagy–lysosome pathway. Liberated β-catenin nuclear translocation increased, binding with LEF1/TCF4 and promoting LDHA transcriptional expression. Additionally, high expression of LDHA was observed in cancer tissues and was positively related to progression.

Conclusion

Our study demonstrated that starvation-induced autophagy modulates glucose metabolic reprogramming by enhancing Axin1 degradation and β-catenin nuclear translocation in BLCA, which promotes the transcriptional expression of LDHA and further malignant progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02303-1.

PDSS1-Mediated Activation of CAMK2A-STAT3 Signaling Promotes Metastasis in Triple-Negative Breast Cancer

Genomic alterations are crucial for the development and progression of human cancers. Copy-number gains found in genes encoding metabolic enzymes may induce triple-negative breast cancer (TNBC) adaptation. However, little is known about how metabolic enzymes regulate TNBC metastasis. Using our previously constructed multiomic profiling of a TNBC cohort, we identified decaprenyl diphosphate synthase subunit 1 (PDSS1) as an essential gene for TNBC metastasis. PDSS1 expression was significantly upregulated in TNBC tissues compared with adjacent normal tissues and was positively associated with poor survival among patients with TNBC. PDSS1 knockdown inhibited TNBC cell migration, invasion, and distant metastasis. Mechanistically, PDSS1, but not a catalytically inactive mutant, positively regulated the cellular level of coenzyme Q10 (CoQ10) and intracellular calcium levels, thereby inducing CAMK2A phosphorylation, which is essential for STAT3 phosphorylation in the cytoplasm. Phosphorylated STAT3 entered the nucleus, promoting oncogenic STAT3 signaling and TNBC metastasis. STAT3 phosphorylation inhibitors (e.g., Stattic) effectively blocked PDSS1-induced cell migration and invasion in vitro and tumor metastasis in vivo. Taken together, our study highlights the importance of targeting the previously uncharacterized PDSS1/CAMK2A/STAT3 oncogenic signaling axis, expanding the repertoire of precision medicine in TNBC. SIGNIFICANCE: A novel metabolic gene PDSS1 is highly expressed in triple-negative breast cancer tissues and contributes to metastasis, serving as a potential therapeutic target for combating metastatic disease.

Silencing PFKP restrains the stemness of hepatocellular carcinoma cells

BACKGROUND

Glycolysis reprogramming is deeply involved in the progression of hepatocellular carcinoma (HCC), in which HCC cells with stemness traits play important roles as well. Thus, whether platelet isoform of phosphofructokinase 1 (PFKP), a rate-limiting enzyme in glycolysis, contributes to the maintenance of stemness of HCC cells is worth investigation.

METHODS

PFKP levels were compared between human hepatocellular carcinoma and adjacent normal tissues by Western blotting and immunohistochemistry. The relationship between PFKP expression and clinic pathological features was also analyzed. Furthermore, the colony formation capabilities and the levels of stemness markers (ALDH1, CD44, CD133, Sox-2) as well as β-catenin were compared between HCC cells either undergoing PFKP silencing or overexpression.

RESULTS

PFKP levels were higher in HCC as compared to normal hepatic tissues. Silencing PFKP decreased HCC proliferation, colony formation capabilities, and levels of stemness markers and β-catenin; whereas overexpressing PFKP demonstrated the opposite effects.

CONCLUSION

PFKP promoted HCC proliferation and contributed to the maintenance of HCC stemness. Silencing PFKP could restrain the stemness of HCC, suggesting that PFKP may be a potential therapeutic target for HCC treatment.

Histone deacetylase 1 facilitates aerobic glycolysis and growth of endometrial cancer

The deregulation of histone deacetylase 1 (HDAC1) is reportedly involved in the progression of several cancer types. However, its function in endometrial cancer remains unknown. The aim of the present study was to clarify the role of HDAC1 in aerobic glycolysis and the progression of endometrial cancer. Lentiviral vector transfection was used to up- and downregulate HDAC1 expression in HEC-1-A endometrial cancer cells. The effects of HDAC1 on cellular proliferation, apoptosis, migration, invasiveness and tumorigenesis were determined by CCK-8, flow cytometry, wound-healing, transwell chamber and in vivo tumor formation experiments, respectively. HDAC1 level was significantly increased in endometrial cancer tissues and cells, and its high expression was associated with advanced clinicopathological progression. HEC-1-A cell proliferation, invasiveness, migration and tumorigenesis were enhanced, and apoptosis was inhibited when HDAC1 was overexpressed. Moreover, upregulation of HDAC1 significantly promoted the epithelial-mesenchymal transition of HEC-1-A cells, and increased glucose consumption, lactate secretion and ATP levels. Collectively, the present study revealed that HDAC1 promoted the aerobic glycolysis and progression of endometrial cancer, which may provide a potential target for endometrial cancer treatment.

Prognostic Roles of Phosphofructokinase Platelet in Clear Cell Renal Cell Carcinoma and Correlation with Immune Infiltration

Background

Abnormal expression of phosphofructokinase platelet (PFKP) has been reported in various cancer types. However, the role of PFKP in clear cell renal cell carcinoma (ccRCC) remains unclear.

Methods

In this study, the PFKP expression levels in various cancers were systemically described by integrating multiple kinds of publicly available databases. The relationship between PFKP expression and clinical prognosis of ccRCC patients was analyzed based on the TCGA database. Furthermore, PFKP-related genes and the top 10 hub genes were identified. The enrichment analysis, PPI network, and the relationship between PFKP and tumor-infiltrating immune cells were conducted to explore why PFKP was associated with clinical outcomes in ccRCC patients.

Results

PFKP was significantly highly expressed in kidney cancer, especially in ccRCC. Moreover, patients with low expression of PFKP were correlated with poor 5-year and 10-year overall survival (OS) (P < 0.05). Low PFKP expression was a risk factor associated with decreased OS in subgroups including males, females, grade 3–4, and stage III–IV (all P < 0.05). GO and KEGG enrichment analyses showed that 10 hub genes were mainly enriched in the tumor immune response. Finally, PFKP expression level was highly correlated with the infiltration of B cell, CD8⁺ T cell, CD4⁺ T cell, macrophage, neutrophil, and dendritic cell.

Conclusion

In short, our findings suggested that PFKP is highly expressed in ccRCC significantly and facilitated tumor immune response which in turn associated with a good prognosis.

Mitophagy: A Novel Therapeutic Target for Treating DN

Diabetic nephropathy (DN) is a common microvascular complication of diabetes and one of the leading causes of end-stage renal disease. Tubular damage is an early change and characteristic of DN, and mitochondrial dysfunction plays an important role in the development of DN. Therefore, the timely removal of damaged mitochondria in tubular cells is an effective treatment strategy for DN. Mitophagy is a type of selective autophagy that ensures the timely elimination of damaged mitochondria to protect cells from oxidative stress. In this review, we summarize our understanding of mitochondrial dysfunction and dynamic disorders in tubular cells in DN and the molecular mechanism of mitophagy. Finally, the role of mitophagy in DN and its feasibility as a therapeutic target for DN are discussed.

[Inhibiting autophagy by silencing ATG5 and ATG7 enhances inhibitory effect of DDP on DDP-resistant I-10 testicular cancer cells]

OBJECTIVE

To observe the changes in autophagy of cisplatin-resistant I-10 testicular cancer cells (I-10/DDP cells) in response to cisplatin treatment and the effect of silencing ATG5 and ATG7 on autophagy and proliferation of cisplatin-treated cells.

OBJECTIVE

I-10/DDP cells treated with 15 μmol/L cisplatin for 12 h were examined for expressions of LC3 and p62 by Western blotting and for autophagy level through transmission electron microscopy and mCherry-GFP-LC3B. I-10/DDP cells were transfected with short hairpin RNAs shRNA-ATG5 or shRNA-ATG7 via Lipfectamine2000, the empty vector (NC group), or Lipfectamine2000 alone (blank control group), and the cellular expressions of ATG5 and ATG7 were detected with Western blotting. The transfected cells were treated with 15 μmol/L cisplatin for 12 h, after that the expressions of LC3 and p62 were detected with Western blotting. Transmission electron microscopy and mCherry-GFP-LC3B were used to detect autophagy level in the cells. MTT assay and colony-forming assay were performed to assess the cell survival fraction and colony formation ability of the treated cells, respectively.

OBJECTIVE

After cisplatin treatmert, the expression level of LC3 II increased significantly (P < 0.001), the expression level of p62 decreased (P < 0.05), and the number of autophagosomes increased in I-10/DDP cells. The cells transfected with shRNA-ATG5 or shRNA-ATG7 showed significantly decreased expressions of ATG5 or ATG7 (P=0.005 or P < 0.001). Cisplatin treatment of the transfected cells obviously reduced the cellular expression of LC3 II (P < 0.001), increased the expression of p62 (P < 0.001), and decreased the number of autophagosomes, cell survival fraction and colony formation ability of the cells (P < 0.001).

OBJECTIVE

Silencing ATG5 and ATG7 inhibits cisplatin-mediated autophagy and enhances the inhibitory effect of cisplatin on inhibiting cell proliferation.

PDIA6 contributes to aerobic glycolysis and cancer progression in oral squamous cell carcinoma

Background/objective

Accumulated evidence has demonstrated that aerobic glycolysis serves as a regulator of tumor cell growth, invasion, and angiogenesis. Herein, we explored the role of protein disulfide isomerase family 6 (PDIA6) in the aerobic glycolysis and the progression of oral squamous cell carcinoma (OSCC).

Methods

The expression pattern of PDIA6 in OSCC tissues was determined by qPCR and western blotting. Lentivirus and small interfering RNAs (siRNAs) were introduced into cells to upregulate and downregulate PDIA6 expression. CCK-8, flow cytometry, transwell, and xenotransplantation models were applied to detect cell proliferation, apoptosis, migration, invasion, and tumorigenesis, respectively.

Results

A high expression pattern of PDIA6 was observed in OSCC tissues, which was closely associated with lower overall survival and malignant clinical features in OSCC. Compared with the control group, overexpression of PDIA6 induced significant enhancements in cell growth, migration, invasiveness, and tumorigenesis and decreased cell apoptosis, while knockdown of PDIA6 caused opposite results. In addition, overexpression of PDIA6 increased glucose consumption, lactate production, and ATP level in OSCC cells.

Conclusion

This study demonstrated that PDIA6 expression was elevated in OSCC tissues, and overexpression of it promoted aerobic glycolysis and OSCC progression.

Construction of the optimization prognostic model based on differentially expressed immune genes of lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common pathology subtype of lung cancer. In recent years, immunotherapy, targeted therapy and chemotherapeutics conferred a certain curative effects. However, the effect and prognosis of LUAD patients are different, and the efficacy of existing LUAD risk prediction models is unsatisfactory.

Methods

The Cancer Genome Atlas (TCGA) LUAD dataset was downloaded. The differentially expressed immune genes (DEIGs) were analyzed with edgeR and DESeq2. The prognostic DEIGs were identified by COX regression. Protein-protein interaction (PPI) network was inferred by STRING using prognostic DEIGs with p value< 0.05. The prognostic model based on DEIGs was established using Lasso regression. Immunohistochemistry was used to assess the expression of FERMT2, FKBP3, SMAD9, GATA2, and ITIH4 in 30 cases of LUAD tissues.

Results

In total,1654 DEIGs were identified, of which 436 genes were prognostic. Gene functional enrichment analysis indicated that the DEIGs were involved in inflammatory pathways. We constructed 4 models using DEIGs. Finally, model 4, which was constructed using the 436 DEIGs performed the best in prognostic predictions, the receiver operating characteristic curve (ROC) was 0.824 for 3 years, 0.838 for 5 years, 0.834 for 10 years. High levels of FERMT2, FKBP3 and low levels of SMAD9, GATA2, ITIH4 expression are related to the poor overall survival in LUAD (p < 0.05). The prognostic model based on DEIGs reflected infiltration by immune cells.

Conclusions

In our study, we built an optimal prognostic signature for LUAD using DEIGs and verified the expression of selected genes in LUAD. Our result suggests immune signature can be harnessed to obtain prognostic insights.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07911-8.

PFKP facilitates ATG4B phosphorylation during amino acid deprivation-induced autophagy

ATG4B facilitates autophagy by promoting autophagosome maturation through the reversible lipidation and delipidation of LC3. Recent reports have shown that phosphorylation of ATG4B regulates its activity and LC3 processing, leading to modulate autophagy activity. However, the mechanism about how ATG4B phosphorylation is involved in amino acid deprivation-induced autophagy is unclear. Here, we combined the tandem affinity purification with mass spectrometry (MS) and identified the ATG4B-interacting proteins including its well-known partner gamma-aminobutyric acid receptor-associated protein (GABARAP, a homolog of LC3) and phosphofructokinase 1 platelet isoform (PFKP). Further immunoprecipitation assays showed that amino acid deprivation strengthened the interaction between ATG4B and PFKP. By genetic depletion of PFKP using CRISPR/Cas9, we uncovered that PFKP loss reduced the degradation of LC3-II and p62 due to a partial block in autophagic flux. Furthermore, MS analysis of Flag-tagged ATG4B immunoprecipitates identified phosphorylation of ATG4B serine 34 residue (S34) and PFKP serine 386 residue (S386) under amino acid deprivation condition. In vitro kinase assay validated that PFKP functioning as a protein kinase phosphorylated ATG4B at S34. This phosphorylation could enhance ATG4B activity and p62 degradation. In addition, PFKP S386 phosphorylation was important to ATG4B S34 phosphorylation and autophagy in HEK293T cells. In brief, our findings describe that PFKP, a rate-limiting enzyme in the glycolytic pathway, functions as a protein kinase for ATG4B to regulate ATG4B activity and autophagy under amino acid deprivation condition.

circPGAM1 enhances autophagy signaling during laryngocarcinoma drug resistance by regulating miR-376a

circRNAs have been shown to be involved in cancer progression. It is unclear whether circPGAM1 exerts its effect on laryngocarcinoma drug resistance. In this study, we employed colony formation and MTT assay to determine colony number and cell viability under cisplatin treatment. TUNEL experiment was used to evaluate apoptosis of laryngocarcinoma cells in the presence of cisplatin. Xenograft tumor experiment was performed to assess in vivo tumor growth of SNU46 cells. We found that circPGAM1 enhanced colony formation and viability of SNU46 and M4E cells. In contrast, circPGAM1 caused attenuated cell apoptosis. Furthermore, we also confirmed that circPGAM1 played a key role in tumor growth in animal model and clinical patients. miR-376a was identified and proved to act as key effector for circPGAM1-mediated drug resistance. Finally, autophagy-related gene ATG2A was shown to rescue miR-376a-modulated drug resistance of laryngocarcinoma cells. Herein, we illuminate the role of circPGAM1 in laryngocarcinoma drug resistance, thereby facilitating development of targeted therapy for treating laryngocarcinoma.

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.

Platelet isoform of phosphofructokinase promotes aerobic glycolysis and the progression of non‑small cell lung cancer

The platelet isoform of phosphofructokinase (PFKP) is a rate-limiting enzyme involved in glycolysis that serves an important role in various types of cancer. The aim of the present study was to explore the specific regulatory relationship between PFKP and non-small cell lung cancer (NSCLC) progression. PFKP expression in NSCLC tissues and corresponding adjacent tissues was detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemical analysis. PFKP expression in human bronchial epithelial cells (16HBE) and NSCLC cells (H1299, H23 and A549) was also detected using RT-qPCR. Cell proliferation was detected by Cell Counting Kit-8 and colony formation assays. Transwell invasion and wound healing assays, and flow cytometry were used to detect cell invasion, migration and apoptosis, respectively. The expression levels of glycolysis-associated enzymes (hexokinase-2, lactate dehydrogenase A and glucose transporter-1), epithelial-mesenchymal transition-related proteins (N-cadherin, vimentin and E-cadherin) and apoptosis-related proteins (caspase-3 and B-cell lymphoma-2) were detected by western blotting. Glucose uptake, lactate production and the adenosine trisphosphate/adenosine diphosphate ratio were measured using the corresponding kits. The results of the present study demonstrated that PFKP expression was upregulated in NSCLC tissues and cells, and PFKP expression was related to lymph node metastasis and histological grade. In addition, overexpression of PFKP inhibited cell apoptosis, and promoted proliferation, migration, invasion and glycolysis of H1299 cells, whereas knockdown of PFKP had the opposite effects. In conclusion, PFKP inhibited cell apoptosis, and promoted proliferation, migration, invasion and glycolysis of NSCLC cells; these findings may lay the foundation for novel treatments of NSCLC.

Fine-tuning the metabolic rewiring and adaptation of translational machinery during an epithelial-mesenchymal transition in breast cancer cells

ABSTRACT

BACKGROUND

During breast cancer progression, the epithelial to mesenchymal transition has been associated with metastasis and endocrine therapy resistance; however, the underlying mechanisms remain elusive. To gain insight into this process, we studied the transition undergone by MCF7-derived cells, which is driven by the constitutive nuclear expression of a MKL1 variant devoid of the actin-binding domain (MKL1 ΔN200). We characterized the adaptive changes that occur during the MKL1-induced cellular model and focused on regulation of translation machinery and metabolic adaptation.

METHODS

We performed a genome-wide analysis at the transcriptional and translational level using ribosome profiling complemented with RNA-Seq and analyzed the expression of components of the translation machinery and enzymes involved in energy metabolism. NGS data were correlated with metabolomic measurements and quantification of specific mRNAs extracted from polysomes and western blots.

RESULTS

Our results reveal the expression profiles of a luminal to basal-like state in accordance with an epithelial to mesenchymal transition. During the transition, the synthesis of ribosomal proteins and that of many translational factors was upregulated. This overexpression of the translational machinery appears to be regulated at the translational level. Our results indicate an increase of ribosome biogenesis and translation activity. We detected an extensive metabolic rewiring occurring in an already "Warburg-like" context, in which enzyme isoform switches and metabolic shunts indicate a crucial role of HIF-1α along with other master regulatory factors. Furthermore, we detected a decrease in the expression of enzymes involved in ribonucleotide synthesis from the pentose phosphate pathway. During this transition, cells increase in size, downregulate genes associated with proliferation, and strongly upregulate expression of cytoskeletal and extracellular matrix genes.

CONCLUSIONS

Our study reveals multiple regulatory events associated with metabolic and translational machinery adaptation during an epithelial mesenchymal-like transition process. During this major cellular transition, cells achieve a new homeostatic state ensuring their survival. This work shows that ribosome profiling complemented with RNA-Seq is a powerful approach to unveil in-depth global adaptive cellular responses and the interconnection among regulatory circuits, which will be helpful for identification of new therapeutic targets.

Salvia miltiorrhiza-Derived Sal-miR-58 Induces Autophagy and Attenuates Inflammation in Vascular Smooth Muscle Cells

Autophagy is associated with the cytoprotection of physiological processes against inflammation and oxidative stress. Salvia miltiorrhiza possesses cardiovascular protective actions and has powerful anti-oxidative and anti-inflammatory effects; however, whether and how Salvia miltiorrhiza-derived microRNAs (miRNAs) protect vascular smooth muscle cells (VSMCs) by inducing autophagy across species are unknown. We first screened and identified Sal-miR-58 from Salvia miltiorrhiza as a natural autophagy inducer. Synthetic Sal-miR-58 suppresses chronic angiotensin II (Ang II) infusion-induced abdominal aortic aneurysm (AAA) formation in mice, as well as induces autophagy in VSMCs and attenuates the inflammatory response elicited by Ang II in vivo and in vitro. Mechanistically, Sal-miR-58 downregulates Krüppel-like factor 3 (KLF3) expression through direct binding to the 3' UTR of KLF3, which in turn relieves KLF3 repression of E3 ubiquitin ligase neural precursor cell-expressed developmentally downregulated 4-like (NEDD4L) expression, whereas NEDD4L upregulation increases the ubiquitination and degradation of the platelet isoform of phosphofructokinase (PFKP), subsequently leading to a decrease in the activation of Akt/mammalian target of rapamycin (mTOR) signaling and facilitating VSMC autophagy induced by Sal-miR-58 in the context of chronic Ang II stimulation and aneurysm formation. Our results provide the first evidence that plant-derived Sal-miR-58 induces autophagy and attenuates inflammation in VSMCs through cross-species modulation of the KLF3/NEDD4L/PFKP regulatory pathway.

Identification of a Glucose Metabolism-related Signature for prediction of Clinical Prognosis in Clear Cell Renal Cell Carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) is one of the most prevalent and invasive histological subtypes among all renal cell carcinomas (RCC). Cancer cell metabolism, particularly glucose metabolism, has been reported as a hallmark of cancer. However, the characteristics of glucose metabolism-related gene sets in ccRCC have not been systematically profiled.

Methods: In this study, we downloaded a gene expression profile and glucose metabolism-related gene set from TCGA (The Cancer Genome Altas) and MSigDB, respectively, to analyze the characteristics of glucose metabolism-related gene sets in ccRCC. We used a multivariable Cox regression analysis to develop a risk signature, which divided patients into low- and high- risk groups. In addition, a nomogram that combined the risk signature and clinical characteristics was created for predicting the 3- and 5-year overall survival (OS) of ccRCC. The accuracy of the nomogram prediction was evaluated using the area under the receiver operating characteristic curve (AUC) and a calibration plot.

Results: A total of 231 glucose metabolism-related genes were found, and 68 differentially expressed genes (DEGs) were identified. After screening by univariate regression analysis, LASSO regression analysis and multivariable Cox regression analysis, six glucose metabolism-related DEGs (FBP1, GYG2, KAT2A, LGALS1, PFKP, and RGN) were selected to develop a risk signature. There were significant differences in the clinical features (Fuhrman nuclear grade and TNM stage) between the high- and low-risk groups. The multivariable Cox regression indicated that the risk score was independent of the prognostic factors (training set: HR=3.393, 95% CI [2.025, 5.685], p<0.001; validation set: HR=1.933, 95% CI [1.130, 3.308], p=0.016). The AUCs of the nomograms for the 3-year OS in the training and validation sets were 0.808 and 0.819, respectively, and 0.777 and 0.796, respectively, for the 5- year OS.

Conclusion: We demonstrated a novel glucose metabolism-related risk signature for predicting the prognosis of ccRCC. However, additional in vitro and in vivo research is required to validate our findings.

Activation of PGK1 under hypoxic conditions promotes glycolysis and increases stem cell‑like properties and the epithelial‑mesenchymal transition in oral squamous cell carcinoma cells via the AKT signalling pathway

Although it has been previously documented that a hypoxic environment can promote glycolysis and the malignant progression of oral squamous cell carcinoma (OSCC) cells, the specific underlying mechanism remains unclear. Phosphoglycerate kinase 1 (PGK1) has been previously reported to serve an important role in tumor metabolism. The aim of the present study was to investigate the effects of hypoxia and PGK1 on glycolysis, stem cell-like properties and epithelial-mesenchymal transition (EMT) in OSCC cells. Cell Counting Kit-8 assays were performed to examine tumor cell viability under hypoxic conditions. Sphere formation, immunohistochemistry, western blotting, Transwell assays and mouse xenograft studies were performed to assess the biological effects of PGK1. Under hypoxic conditions, phosphoglycerate PGK1 expression was found to be upregulated, which resulted in the potentiation of stem cell-like properties and enhancement of EMT. However, PGK1 knockdown reversed hypoxia-mediated glycolysis, stem cell-like properties, EMT in addition to inhibiting OSCC cell invasion and migration. PGK1 knockdown also inhibited tumour growth, whilst the overexpression of PGK1 was demonstrated to promote tumour growth in mouse xenograft models in vivo. Downstream, activation of the AKT signalling pathway reversed the series of changes induced by PGK1 knockdown. PGK1 expression was found to be upregulated in human OSCC tissues, which was associated with the pathological differentiation of tumours and lymph node metastasis. To conclude, results from the present study demonstrate that hypoxia can increase PGK1 expression, resulting in the promotion of glycolysis, enhancing stem cell-like properties and EMT by activating AKT signalling in OSCC.

PFKP is transcriptionally repressed by BRCA1/ZBRK1 and predicts prognosis in breast cancer

Objectives

The present study aims to elucidate the underlying mechanism how PFKP is regulated by BRCA1 and the clinical significance of PFKP in breast cancer.

Methods

MEF-BRCA1^△/△ and the wild type counterpart MEF-BRCA1^+/+ cell lines were used to test the sensitivity of glucose depletion in culture medium. Glucose Assay Kit was used to quantify glucose levels in cultural supernatant and cell lysate. Real time PCR was used to measure the mRNA expression levels of genes. Western blot was used to detect protein levels. Chromatin immunoprecipitation was used to verify the bindings between transcription factors and DNA elements. Luciferase reporter assay was performed to determine the transcriptional activity. Histochemistry assay was performed on tissue microarray.

Results

We found that MEF-BRCA1^△/△ cells consumed more glucose and were more vulnerable to glucose-deprived culture medium. The mRNA profiles and qPCR assay of MEF-BRCA1^△/△ and MEF-BRCA1^+/+ cells revealed that PFKP, the rate-limiting enzyme of glycolysis, was significantly upregulated in MEF-BRCA1^△/△ cells. Consistently, the repressive effects of BRCA1 on PFKP were confirmed by overexpression or knockdown of BRCA1. Moreover, we also demonstrated that PFKP was suppressed by ZBRK1 as well, which was the co-repression partner of BRCA1. Mechanistically, we figured out that BRCA1 formed a transcriptional repression complex with ZBRK1 on the promoter of PFKP and consequently restrained its expression. Importantly, the expression levels of PFKP were demonstrated to associate with poor survival of patients with breast cancer.

Conclusion

Our study provided a new insight into the dysregulation of glycolysis in breast cancer, which might be partially due to the deficiency of BRCA1/ZBRK1 axis and subsequently reversed the transcriptional repressive effect on PFKP. We also found that PFKP overexpressed in a subset of breast cancer patients and could serve as a prognostic factor, which represented a potential target for BC therapy.

PFKP is highly expressed in lung cancer and regulates glucose metabolism

PURPOSE

Although it has been reported that up-regulation of phosphofructokinase (PFK) expression is a major feature of malignant tumors, the role of platelet type PFK (PFKP) in tumor initiation and progression is as yet poorly understood. The objective of this study was to evaluate PFKP expression in lung cancer and its effect on glycolysis, and to explore correlations between PFKP expression levels and clinical lung cancer patient features.

METHODS

PFKP mRNA expression levels in cancer tissues and adjacent normal tissues were compared using The Cancer Genome Atlas (TCGA) database. PFKP mRNA and protein expression levels in fresh lung cancer tissues and cell lines were assessed using quantitative real-time PCR and Western blotting. Immunohistochemistry (IHC) was used to assess PFKP expression in 150 archival lung adenocarcinoma samples, after which follow-up data and their correlations with clinical features and patient prognosis were evaluated. A retroviral shRNA-mediated method was used to construct stable cell lines expressing low levels of PFKP. Glucose, lactate and adenosine triphosphate concentrations in the cell culture supernatants were determined using enzymatic, spectrophotometric and enzyme-linked immunosorbent (ELISA) assays, respectively. The effect of PFKP expression on the proliferation of lung cancer cells was assessed using colony forming, MTT and flow cytometry assays, respectively. Finally, data from tissue samples of 533 patients with lung adenocarcinoma and 502 patients with lung squamous cell carcinoma were downloaded from the TCGA database, after which pathway and gene correlation information was retrieved using gene set enrichment analyses.

RESULTS

We found that PFKP was highly expressed in lung cancer tissues and cell lines. Using IHC we found that PFKP was highly expressed in primary lung adenocarcinoma tissues and that a high expression was associated with a poor prognosis. Clinical data analysis revealed that the PFKP expression levels correlated with tumor size and patient survival. Lung cancer cell lines with decreased PFKP expression levels showed significant decreases in glucose uptake rates, lactate levels and adenosine triphosphate concentrations. They also exhibited significantly decreased proliferation rates, colony forming abilities and increased G2/M cell cycle phase percentages. Gene set enrichment analysis revealed that multiple pathways, including glycolytic pathways, may be involved in the regulation PFKP.

CONCLUSIONS

Our data indicate that PFKP is highly expressed in lung cancer tissues and cell lines and is associated with tumor size and patient prognosis. As such, PFKP may serve as a prognostic biomarker. We also found that PFKP regulates the level of glycolysis in lung cancer cells and is associated with lung cancer cell proliferation. These data may be instrumental for the design of new lung cancer treatment options.

LDHA Promotes Oral Squamous Cell Carcinoma Progression Through Facilitating Glycolysis and Epithelial-Mesenchymal Transition

Aerobic glycolysis is the main pathway for energy metabolism in cancer cells. It provides energy and biosynthetic substances for tumor progression and metastasis by increasing lactate production. Lactate dehydrogenase A (LDHA) promotes glycolysis process by catalyzing the conversion of pyruvate to lactate. Despite LDHA exhibiting carcinogenesis in various cancers, its role in oral squamous cell carcinoma (OSCC) remains unclear. This study demonstrated that LDHA was over-expressed in both OSCC tissues and cell lines, and was significantly associated with lower overall survival rates in patients with OSCC. Using weighted gene correlation network analysis and gene set enrichment analysis for the gene expression data of patients with OSCC (obtained from The Cancer Genome Atlas database), a close association was identified between epithelial–mesenchymal transition (EMT) and LDHA in promoting OSCC progression. The knockdown of LDHA suppressed EMT, cell proliferation, and migration and invasion of OSCC cells in vitro. Moreover, the silencing of LDHA inhibited tumor growth in vivo. Oxamate, as a competitive LDHA inhibitor, was also suppressed diverse malignant biocharacteristics of OSCC cells. Our findings reveal that LDHA acts as an oncogene to promote malignant progression of OSCC by facilitating glycolysis and EMT, and LDHA may be a potential anticancer therapeutic target.

Hypoxia-inducible Factor-1α Mediates Hyperglycemia-induced Pancreatic Cancer Glycolysis

BACKGROUND

Recent studies have suggested that 85% of pancreatic cancer patients accompanied with impaired glucose tolerance or even Diabetes Mellitus (DM) and the invasive and migratory abilities of pancreatic cancer could be enhanced by high glucose. This study aimed to investigate whether Hypoxia- Inducible Factor-1α (HIF-1α) mediates hyperglycemia-induced pancreatic cancer glycolysis.

METHODS

The cellular glycolytic activity was assessed by determining lactate production, glucose uptake and lactate dehydrogenase enzymatic activity. Pancreatic cancer cells (BxPC-3 cells) were transfected with short hairpin RNA targeting the HIF-1α.

RESULTS

Hyperglycemia promotes pancreatic cancer glycolysis. Lactate dehydrogenase A (LDHA) activity and hexokinase 2 (HK2), platelet-type of phosphofructokinase (PFKP) expression were significantly upregulated under hyperglycemic conditions. HIF-1α knockdown prominently down-regulated the activity of LDHA and the expression of HK2, PFKP and decreased lactate production in BxPC-3 cells. Under hypoxia condition, hyperglycemia induced pancreatic glycolysis by mechanisms that are both dependent on HIF-1α and independent of it.

CONCLUSION

The accumulation of HIF-1α induced by hyperglycemia increases LDHA activity and HK2, PFKP expression, thereby promoting pancreatic glycolysis to facilitate cancer progression.