STIP1 down-regulation inhibits glycolysis by suppressing PKM2 and LDHA and inactivating the Wnt/β-catenin pathway in cervical carcinoma cells

Stress-inducible phosphoprotein 1 (Sti1/Stip1/Hop) sequesters misfolded proteins during stress

Co-chaperones are key elements of cellular protein quality control. They cooperate with the major heat shock proteins Hsp70 and Hsp90 in folding proteins and preventing the toxic accumulation of misfolded proteins upon exposure to stress. Hsp90 interacts with the co-chaperone stress-inducible phosphoprotein 1 (Sti1/Stip1/Hop) and activator of Hsp90 ATPase protein 1 (Aha1) among many others. Sti1 and Aha1 control the ATPase activity of Hsp90, but Sti1 also facilitates the transfer of client proteins from Hsp70 to Hsp90, thus connecting these two major branches of protein quality control. We find that misbalanced expression of Sti1 and Aha1 in yeast and mammalian cells causes severe growth defects. Also, deletion of STI1 causes an accumulation of soluble misfolded ubiquitinated proteins and a strong activation of the heat shock response. We discover that, during proteostatic stress, Sti1 forms cytoplasmic inclusions in yeast and mammalian cells that overlap with misfolded proteins. Our work indicates a key role of Sti1 in proteostasis independent of its Hsp90 ATPase regulatory functions by sequestering misfolded proteins during stress.

The Keap1-Nrf2/ARE signaling pathway regulates redox balance and apoptosis in the small yellow croaker (Larimichthys polyactis) under hypoxic stress

Hypoxic stress can result in redox imbalance and apoptosis in teleostean fishes; however, the precise molecular mechanisms underlying this process, including its regulation by the key signaling pathway Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 related factor (Nrf2)/antioxidant response element (ARE), remain elusive. Therefore, in this study, we chose the Keap1-Nrf2/ARE signaling pathway as the entry point and a combination of in vivo (target organ liver) and in vitro (small yellow croaker fry [SYCF] cell line) experiments to investigate the molecular mechanism by which Larimichthys polyactis (L. polyactis) adapts to hypoxic stress by regulating redox balance and apoptosis. As our previous study found that hypoxic stress could lead to redox imbalance and apoptosis in L. polyactis. First, we observed significant alterations in the expression of key genes Lpkeap1, Lpnrf2, Lpho-1, and Lpnqo1 within the Keap1-Nrf2/ARE signaling pathway in both liver tissue and SYCF cells of L. polyactis under hypoxic stress, indicating activation of this pathway in response to hypoxia. Subsequently, we elucidated the mechanism by which hypoxia activates this pathway, that is, hypoxia weakened the interaction between LpNrf2 and LpKeap1, promoting the nuclear translocation of LpNrf2 and enhancing its binding activity to ARE, thereby activating the transcription of target genes. Furthermore, we found that significant changes occurred in the redox balance and apoptosis-related indicators after LpNrf2 knockdown and exposure to hypoxic stress for 24 h in SYCF cells, indicating that this pathway can regulate redox balance and apoptosis regulation under hypoxic stress in L. polyactis. Additionally, we used DNA affinity purification sequencing (DAP-seq) to identify the ARE sequence (ATGATTTAGC) that bound to LpNrf2 and its target genes. Finally, we conducted a combined analysis of DAP-seq and RNA-seq to identify six key target genes involved in the process: haeme oxygenase-1 (Ho-1), B-cell lymphoma-2 (Bcl2), pituitary homeobox 2 isoform X1 (Pitx2), aquaporin-4 isoform X1 (Aqp4), stress-induced phosphoprotein 1-like isoform X1 (Stip1), and guanine nucleotide-binding protein G (i) subunit alpha-2-like (Gnai2). In summary, hypoxic stress induced by weakening LpNrf2 and LpKeap1 interaction promoted LpNrf2 nuclear entry and enhanced its binding activity to ARE, thereby activating the transcription of multiple target genes to regulate redox balance and apoptosis. The research results not only help deepen our understanding of the adaptive mechanisms of L. polyactis and even marine fish to hypoxic stress and its survival strategies but also provide new ideas and potential targets for breeding new hypoxia-tolerant strains.

Interpretable Machine Learning Algorithms Identify Inetetamab-Mediated Metabolic Signatures and Biomarkers in Treating Breast Cancer

BACKGROUND

HER2-positive breast cancer (BC), a highly aggressive malignancy, has been treated with the targeted therapy inetetamab for metastatic cases. Inetetamab (Cipterbin) is a recently approved targeted therapy for HER2-positive metastatic BC, significantly prolonging patients' survival. Currently, there is no established biomarker to reliably predict or assess the therapeutic efficacy of inetetamab in BC patients.

METHODS

This study harnesses the power of metabolomics and machine learning to uncover biomarkers for inetetamab in BC therapy. A total of 23 plasma samples from inetetamab-treated BC patients were collected and stratified into responders and nonresponders. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was utilized to analyze the metabolites in blood samples. A combination of univariate and multivariate statistical analyses was employed to identify these metabolites, and their biological functions were then ascertained by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Finally, machine learning algorithms were employed to screen responsive biomarkers from all differentially expressed metabolites.

RESULTS

Our finding revealed 6889 unique metabolites that were detected. Pathways like retinol metabolism, fatty acid biosynthesis, and steroid hormone biosynthesis were enriched for differentially expressed metabolites. Notably, two key metabolites associated with inetetamab response in BC were identified: FAPy-adenine and 2-Pyrocatechuic acid. There was some negative correlation between progress-free survival (PFS) and their kurtosis content.

CONCLUSIONS

In summary, the identification of these two significant differential metabolites holds promise as potential biomarkers for evaluating and predicting inetetamab treatment outcomes in BC, ultimately contributing to the diagnosis of the disease and the discovery of prognostic markers.

Targeting glucose metabolism for HPV-associated cervical cancer: A sweet poison

More than 99 % of precancerous cervical lesions are associated with human papillomavirus (HPV) infection, with HPV types 16 and 18 (especially type 16) found in over 70 % of cervical cancer cases globally. The growth of HPV-positive cervical cancer depends on the sustained expression of the viral oncogenes E6 and E7, which are key factors in maintaining the malignant phenotype of HPV-positive tumor cells. E6 and E7 oncoproteins can cause the degradation of the tumor suppressor gene p53 and the inactivation of pRb, respectively, thereby inducing carcinogenesis. However, the inhibition of p53 and pRb cannot fully explain the oncogenic mechanism of cervical cancer. Although the development of the HPV vaccine has controlled the incidence of HPV infection, its application and widespread adoption remain limited. In addition, many developing countries cannot afford the cost of vaccines. More importantly, the vaccine only prevents HPV infection and does not provide an effective treatment for patients who are already infected or have cervical cancer. Therefore, HPV-related diseases, especially cervical cancer, remain a serious challenge. This article reviews the role of glucose metabolism changes and key molecular events in HPV-induced cervical cancer, summarizes potential targets for the treatment of cervical cancer, and provides strategies for future clinical treatment. It also offers a theoretical basis for research into cervical cancer and other HPV-related tumors. Furthermore, we discuss potential treatments for HPV-associated cervical cancer through targeted metabolic pathways and analyze the risks and challenges of current targeted glucose metabolism therapies for cervical cancer.

Stress-induced phosphoprotein 1: how does this co-chaperone influence the metastasis steps?

In several cancer types, metastasis is associated with poor prognosis, survival, and quality of life, representing a life risk more significant than the primary tumor itself. Metastasis is a multi-step process that spreads tumor cells from primary sites to surrounding or distant organs, originating secondary tumors. The interconnected steps that drive metastasis depend of several capabilities that enable cells to detach from the primary tumor, acquire motility and migrate through the basal membrane; invade and spread through the vascular system, and finally settle and originate a new tumor. Recently, stress-induced phosphoprotein 1 (STIP1) has emerged as a protein capable of driving tumor cells through these metastasis steps by mediating several biological processes and signaling pathways. This protein is mainly known for its function as a co-chaperone, acting as a scaffold for the interaction of its client heat-shock proteins Hsp70/90 chaperones; however, it is also known that STIP1 can act independently of chaperones to activate downstream phosphorylation pathways. The over-expression of STIP1 has been reported across various cancer types, identifying it as a potential biomarker for predicting patient prognosis and monitoring the progression of metastasis. Here, we present a discussion on how this co-chaperone mediates the initial steps of metastasis (cell adhesion loss, epithelial-to-mesenchymal transition, and angiogenesis), highlighting the biological mechanisms in which STIP1 plays a vital role, also presenting an overview of the current knowledge regarding its clinical relevance.

Natural products as glycolytic inhibitors for cervical cancer treatment: A comprehensive review

Cervical cancer, a prevalent gynaecological malignancy, presents challenges in late-stage treatment efficacy. Aerobic glycolysis, a prominent metabolic trait in cervical cancer, emerges as a promising target for novel drug discovery. Natural products, originating from traditional medicine, represent a significant therapeutic avenue and primary source for new drug development. This review explores the regulatory mechanisms of glycolysis in cervical cancer and summarises natural compounds that inhibit aerobic glycolysis as a therapeutic strategy. The glycolytic phenotype in cervical cancer is regulated by classical molecules such as HIF-1, HPV virulence factors and specificity protein 1, which facilitate the Warburg effect in cervical cancer. Various natural products, such as artemisinin, shikonin and kaempferol, exert inhibitory effects by downregulating key glycolytic enzymes through signalling pathways such as PI3K/AKT/HIF-1α and JAK2/STAT3. Despite challenges related to drug metabolism and toxicity, these natural compounds provide novel insights and promising avenues for cervical cancer treatment.

Quantitative proteome and lysine succinylome characterization of zinc chloride smoke-induced lung injury in mice

The inhalation of zinc chloride (ZnCl2) smoke is one of common resources of lung injury, potentially resulting in severe pulmonary complications and even mortality. The influence of ZnCl2 smoke on lysine succinylation (Ksucc) in the lungs remains uncertain. In this study, we used a ZnCl2 smoke inhalation mouse model to perform global proteomic and lysine succinylome analyses. A total of 6781 Ksucc sites were identified in the lungs, with injured lungs demonstrating a reduction to approximately 2000 Ksucc sites, and 91 proteins exhibiting at least five differences in the number of Ksucc sites. Quantitative analysis revealed variations in expression of 384 proteins and 749 Ksucc sites. The analysis of protein-protein interactions was conducted for proteins displaying differential expression and differentially expressed lysine succinylation. Notably, proteins with altered Ksucc exhibited increased connectivity compared with that in differentially expressed proteins. Beyond metabolic pathways, these highly connected proteins were also involved in lung injury-associated pathological reactions, including processes such as focal adhesion, adherens junction, and complement and coagulation cascades. Collectively, our findings contribute to the understanding of the molecular mechanisms underlaying ZnCl2 smoke-induced lung injury with a specific emphasis on lysine succinylation. These findings could pave the way for targeted interventions and therapeutic strategies to mitigate severe pulmonary complications and mortality associated with such injuries in humans.

PDLIM1 interacts with HK2 to promote gastric cancer progression through enhancing the Warburg effect via Wnt/β-catenin signaling

PDZ and LIM domain protein 1 (PDLIM1) is a cytoskeletal protein and is associated with the malignant pathological features of several tumors. However, the prognostic value of PDLIM1 and the molecular mechanisms by which it is involved in the metabolism and progression in gastric cancer (GC) are still unclear. The GEPIA database was used to predict the expression and prognosis of PDLIM1 in GC. qRT-PCR and western blot assays were applied to detect the mRNA and protein expression in GC tissues and cells. Loss- and gain-of-function experiments were performed to evaluate the biological role of PDLIM1 in GC cells. The Warburg effect was detected by a battery of glycolytic indicators. The interaction of PDLIM1 and hexokinase 2 (HK2) was determined by a co-immunoprecipitation assay. Furthermore, the modulatory effects of PDLIM1 and HK2 on Wnt/β-catenin signaling were assessed. The results showed that PDLIM1 expression was upregulated in GC tissues and cells and was associated with a poor prognosis for GC patients. PDLIM1 inhibition reduced GC cell proliferation, migration and invasion and promoted cell apoptosis. In the glucose deprivation (GLU-D) condition, the PDLIM1 level was reduced and PDLIM1 overexpression led to an increase in glycolysis. Besides, mechanistic investigation showed that PDLIM1 interacted with HK2 to mediate biological behaviors and the glycolysis of GC through Wnt/β-catenin signaling under glucose deprivation. In conclusion, PDLIM1 interacts with HK2 to promote gastric cancer progression by enhancing the Warburg effect via Wnt/β-catenin signaling.

The hsa_circ_0000276-ceRNA regulatory network and immune infiltration in cervical cancer

BACKGROUND

Our previous studies have confirmed that miR-154-5p can regulate pRb expression, and thus, play a tumor suppressor role in HPV16 E7-induced cervical cancer. However, its upstream molecules have not been elucidated in the progression of cervical cancer. This study aimed to explore the role of the miR-154-5p upstream molecule, hsa_circ_0000276 in cervical cancer development and its possible mechanisms of action.

METHODS

We detected differences in whole transcriptome expression profiles of cervical squamous carcinoma and tissues adjacent to cervical cancer tissues from patients using microarray technology to predict circular RNAs (circRNAs) with binding sites to miR-154-5p. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa_circ_0000276 (which had the strongest binding capacity to miR-154 and was selected as the target molecule) in cervical cancer tissues, followed by in vitro functional assays. Downstream microRNAs (miRNAs) and mRNAs of hsa_circ_0000276 were identified using transcriptome microarray data and databases, while the protein-protein interaction networks were obtained using STRING. A competing endogenous RNA (ceRNA) network centered on hsa_circ_0000276 was constructed using Cytoscape and GO and KEGG databases. Abnormal expression and prognosis of critical downstream molecules were analyzed using gene databases and molecular experiments. qRT-PCR and western blot analysis was performed to verify the expression of candidate genes.

RESULTS

We identified 4,001 differentially expressed circRNAs between HPV16-positive cervical squamous carcinoma and benign cervical tissues and 760 circRNAs targeting miR-154-5p, including hsa_circ_0000276. hsa_circ_0000276 and miR-154-5p directly bound, and hsa_circ_0000276 was upregulated, in cervical precancerous lesions and cervical cancer tissues and cells. Silencing hsa_circ_0000276 inhibited G1/S transition and cell proliferation and promoted apoptosis in SiHa and CaSki cells. Bioinformatics analysis showed that the hsa_circ_0000276 ceRNA network included 17 miRNAs and seven mRNAs, and downstream molecules of hsa_circ_0000276 were upregulated in cervical cancer tissues. These downstream molecules were associated with a poor prognosis and affected cervical cancer-associated immune infiltration. Of these, expression of CD47, LDHA, PDIA3, and SLC16A1 was downregulated in sh_hsa_circ_0000276 cells.

CONCLUSIONS

Our findings show that hsa_circ_0000276 exerts cancer-promoting effects in cervical cancer and is an underlying biomarker for cervical squamous cell carcinoma.

2-Deoxy-D-glucose simultaneously targets glycolysis and Wnt/β-catenin signaling to inhibit cervical cancer progression

Cervical cancer is one of the most common female malignant tumors, with typical cancer metabolism characteristics of increased glycolysis flux and lactate accumulation. 2-Deoxy-D-glucose (2-DG) is a glycolysis inhibitor that acts on hexokinase, the first rate-limiting enzyme in the glycolysis pathway. In this research, we demonstrated that 2-DG effectively reduced glycolysis and impaired mitochondrial function in cervical cancer cell lines HeLa and SiHa. Cell function experiments revealed that 2-DG significantly inhibited cell growth, migration, and invasion, and induced G0/G1 phase arrest at non-cytotoxic concentrations. In addition, we found that 2-DG down-regulated Wingless-type (Wnt)/β-catenin signaling. Mechanistically, 2-DG accelerated the degradation of β-catenin protein, which resulted in the decrease of β-catenin expression in both nucleus and cytoplasm. The Wnt agonist lithium chloride and β-catenin overexpression vector could partially reverse the inhibition of malignant phenotype by 2-DG. These data suggested that 2-DG exerted its anti-cancer effects on cervical cancer by co-targeting glycolysis and Wnt/β-catenin signaling. As expected, the combination of 2-DG and Wnt inhibitor synergistically inhibited cell growth. It is noteworthy that, down-regulation of Wnt/β-catenin signaling also inhibited glycolysis, indicating a similar positive feedback regulation between glycolysis and Wnt/β-catenin signaling. In conclusion, we investigated the molecular mechanism by which 2-DG inhibits the progression of cervical cancer in vitro, elucidated the interregulation between glycolysis and Wnt/β-catenin signaling, and preliminarily explored the effect of combined targeting of glycolysis and Wnt/β-catenin signaling on cell proliferation, which provides more possibilities for the formulation of subsequent clinical treatment strategies.

Stress induced phosphoprotein 1 overexpression controls proliferation, migration and invasion and is associated with poor survival in oral squamous cell carcinoma

Objective

Although there have been remarkable achievements in the molecular landscape of oral squamous cell carcinoma (OSCC) in recent years, bringing advances in the understanding of its pathogenesis, development and progression, little has been applied in the prognosis and choosing the optimal treatment. In this study, we explored the influence of the stress induced phosphoprotein 1 (STIP1), which is frequently reported to be highly expressed in many cancers, in OSCCs.

Methods

STIP1 expression was assessed in the TCGA database and in two independent cohorts by immunohistochemistry. Knockdown strategy was applied in OSCC cell lines to determine the impact of STIP1 on viability, proliferation, migration and invasion. The zebrafish model was applied for studying tumor formation and metastasis in vivo. The association of STIP1 and miR-218-5p was explored by bioinformatics and mimics transfection.

Results

STIP1 was highly expressed in OSCCs and significantly associated with shortened survival and higher risk of recurrence. STIP1 down-regulation decreased proliferation, migration and invasion of tumor cells, and reduced the number of metastases in the Zebrafish model. STIP1 and miR-218-5p were inversely expressed, and the transfection of miR-218-5p mimics into OSCC cells decreased STIP1 levels as well as proliferation, migration and invasion.

Conclusion

Our findings show that STIP1 overexpression, which is inversely associated with miR-218-5p levels, contributes to OSCC aggressiveness by controlling proliferation, migration and invasion and is a determinant of poor prognosis.

Hsp70/Hsp90 Organising Protein (Hop): Coordinating Much More than Chaperones

The Hsp70/Hsp90 organising protein (Hop, also known as stress-inducible protein 1/STI1/STIP1) has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins, although recent evidence suggests that eukaryotic Hop is regulatory within chaperone complexes rather than essential. Consequently, Hop is implicated in many key signalling pathways, including aberrant pathways leading to cancer. Hop is also secreted, and it is now well established that Hop interacts with the prion protein, PrP^C, to mediate multiple signalling events. The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrP^C. While the various cellular functions of Hop have been described, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseased states.

Cancer-derived exosomal circ_0038138 enhances glycolysis, growth, and metastasis of gastric adenocarcinoma via the miR-198/EZH2 axis

This study aims to decipher the impact and downstream mechanisms of the bioinformatically identified circ_0038138 delivered by cancer-derived exosomes in gastric adenocarcinoma (GAC). Expression of circ_0038138 in clinical GAC tissues and exosomes (Exos) from clinical plasma samples (plasma-Exos) was predicted by bioinformatics analysis and validated by RT-qPCR. The binding affinity between circ_0038138, miR-198 and EZH2 was identified using luciferase activity, RIP, and RNA pull-down assays. GAC cells (AGS) were co-cultured with Exos isolated from GAC cell supernatant (GC9811-P). After co-culture, the behaviors of GAC cells including proliferation and glycolysis were assessed to identify the biological effect of exosomal circ_0038138. Also, in vivo effects of exosomal circ_0038138 on the tumorigenesis and lung metastasis of GAC cells were evaluated by developing nude mouse xenograft and metastatic models. circ_0038138 upregulation was detected in GAC tissues and plasma-Exos. Exos delivered circ_0038138 to GAC cells and potentiated the proliferative, migratory, invasive, and glycolytic potentials of GAC cells. Mechanistically, circ_0038138 competitively bound to miR-198, which in turn targeted EZH2 by binding to its 3'-UTR. Silencing of EZH2 promoted CXXC4 expression and inhibited Wnt/β-catenin pathway activation, thus repressing the malignancy and glycolysis of GAC cells. In vivo assay confirmed that exosomal circ_0038138 induced tumorigenesis and lung metastasis by regulating the miR-198/EZH2 axis. Collectively, our work suggests that the Exo-mediated transfer of circ_0038138 potentially facilitates the glycolysis, growth and metastasis of GAC cells via miR-198/EZH2 axis, which offers a potential prognostic marker and a therapeutic target for GAC.

Exploring YAP1-centered networks linking dysfunctional CFTR to epithelial-mesenchymal transition

In this work, a systems biology approach identifies potentially dysregulated EMT signaling in CF (including the Hippo, Wnt, TGF-β, p53, and MYC pathways), integrated by YAP1 and TEAD4.

Mutations in the CFTR anion channel cause cystic fibrosis (CF) and have also been related to higher cancer incidence. Previously we proposed that this is linked to an emerging role of functional CFTR in protecting against epithelial–mesenchymal transition (EMT). However, the pathways bridging dysfunctional CFTR to EMT remain elusive. Here, we applied systems biology to address this question. Our data show that YAP1 is aberrantly active in the presence of mutant CFTR, interacting with F508del, but not with wt-CFTR, and that YAP1 knockdown rescues F508del-CFTR processing and function. Subsequent analysis of YAP1 interactors and roles in cells expressing either wt- or F508del-CFTR reveal that YAP1 is an important mediator of the fibrotic/EMT processes in CF. Alongside, five main pathways emerge here as key in linking mutant CFTR to EMT, namely, (1) the Hippo pathway; (2) the Wnt pathway; (3) the TGFβ pathway; (4) the p53 pathway; and (5) MYC signaling. Several potential hub proteins which mediate the crosstalk among these pathways were also identified, appearing as potential therapeutic targets for both CF and cancer.

Chinese Poplar Propolis Inhibits MDA-MB-231 Cell Proliferation in an Inflammatory Microenvironment by Targeting Enzymes of the Glycolytic Pathway

Propolis is rich in flavonoids and has excellent antitumor activity. However, little is known about the potential effects of propolis on glycolysis in tumor cells. Here, the antitumor effects of propolis against human breast cancer MDA-MB-231 cells in an inflammatory microenvironment stimulated with lipopolysaccharide (LPS) were investigated by assessing the key enzymes of glycolysis. Propolis treatment obviously inhibited MDA-MB-231 cell proliferation, migration and invasion, clone forming, and angiogenesis. Proinflammatory mediators, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6, as well as NLRP3 inflammasomes, were decreased following propolis treatment when compared with the LPS group. Moreover, propolis treatment significantly downregulated the levels of key enzymes of glycolysis–hexokinase 2 (HK2), phosphofructokinase (PFK), pyruvate kinase muscle isozyme M2 (PKM2), and lactate dehydrogenase A (LDHA) in MDA-MB-231 cells stimulated with LPS. After treatment with 2-deoxy-D-glucose (2-DG), an inhibitor of glycolysis, the inhibitory effect of propolis on migration was not significant when compared with the LPS group. In addition, propolis increased reactive oxygen species (ROS) levels and decreased mitochondrial membrane potential. Taken together, these results indicated that propolis targeted key enzymes of glycolysis to suppress the proliferation of MDA-MB-231 cells in an inflammatory microenvironment. These studies provide a molecular basis for propolis as a natural anticancer agent against breast cancer.