Sp1 promotes tumour progression by remodelling the mitochondrial network in cervical cancer

Targeted demethylation of the EphA7 promoter inhibits tumorigenesis via the SP1/DNMT1 and PI3K/AKT axes and improves the response to multiple therapies in cervical cancer

Aberrant methylation of the EphA7 promoter has been observed in cervical cancer (CC); however, its precise function and role in CC remain largely unknown. In this study, we investigated the role and molecular mechanisms of EphA7 promoter methylation in cervical carcinogenesis. First, our results indicated that the reactivation of EphA7 expression via a CRISPR demethylation tool (dCas9-Tet1) had antitumor effects. It restrained tumor proliferation and invasion while promoting apoptosis via the PI3K/AKT signaling pathway in both CaSki and SiHa cells. The upstream interacting factors were subsequently captured by CRISPR-mediated pull-down in situ, and the result revealed that SP1 and MAZ interacted with the promoter of EphA7. However, the perturbation results revealed that EphA7 expression was associated with SP1/DNMT1 but not MAZ. Furthermore, 17-β-estradiol (E2) can upregulate EphA7 expression through demethylation via the SP1/DNMT1 axis. A rescue experiment revealed that interference with SP1 expression could restore the effect of E2 on increasing the expression of EphA7 by upregulating estrogen receptor expression. In addition, EphA7 demethylation reduced the half-maximal inhibitory concentration (IC50) of cisplatin and paclitaxel. Pooled analysis revealed that EphA7 promoter hypermethylation was positively correlated with tumor purity but negatively correlated with immune cell infiltration, cytotoxic T lymphocyte (CTL) and immune checkpoint (IC) activity, and the expression of EphA7 was significantly positively correlated with tumor mutational burden (TMB), microsatellite instability (MSI) and the presence of single nucleotide variant (SNV) neoantigens, suggesting a better prognosis for patients with EphA7 promoter hypomethylation and high expression. Collectively, these findings indicate that targeted demethylation of the EphA7 promoter and restoration of endogenous EphA7 expression by dCas9-Tet1 are promising therapeutic approaches and are favorable for the prognosis of CC patients.

[Integrative transcriptomics-metabolomics approach to identify metabolic pathways regulated by glutamine synthetase activity]

Glutamine synthetase (GS), the only enzyme responsible for de novo glutamine synthesis, plays a significant role in cancer progression. As an example of the consequences of GS mutations, the R324C variant causes congenital glutamine deficiency, which results in brain abnormalities and neonatal death. However, the influence of GS-deficient mutations on cancer cells remains relatively unexplored. In this study, we investigated the effects of GS and GS-deficient mutations, including R324C and previously unreported K241R, which serve as models for GS inactivation. This study provided intriguing insights into the intricate relationship between GS mutations and cancer cell metabolism. Our findings strongly support recent studies that suggest GS deletion leads to the suppression of diverse signaling cascades associated with glutamine metabolism under glutamine-stripping conditions. The affected processes include DNA synthesis, the citric acid cycle, and reactive oxygen species (ROS) detoxification. This suppression originates from the inherent inability of cells to autonomously synthesize glutamine under glutamine-depleted conditions. As a key source of reduced nitrogen, glutamine is crucial for the formation of purine and pyrimidine bases, which are essential building blocks for DNA synthesis. Furthermore, the citric acid cycle is inhibited by the absence of negatively charged glutamate within the mitochondrial matrix, particularly when glutamine is scarce. This deficiency decreases the flux of α-ketoglutarate (α-KG), a principal driver of the citric acid cycle. Intermediate metabolites of the citric acid cycle directly or indirectly contribute to the generation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a core component of redox homeostasis. Using the GS_R324C and GS_K241R mutants, we conducted an integrative transcriptomics and metabolomics analysis. The GS mutants with reduced activity activated multiple amino acid biosynthesis pathways, including arginine-proline, glycine-serine-threonine, and alanine-aspartate-glutamate metabolism. This intriguing behavior led us to hypothesize that despite hindrance of the citric acid cycle, abundant intracellular glutamate is redirected through alternative processes, including transamination. Simultaneously, key metabolic enzymes in the amino acid synthesis pathways, such as glutamic-oxaloacetic transaminase 1 (GOT1), glutamic-pyruvic transaminase 2 (GPT2), pyrroline-5-carboxylate reductase 1 (PYCR1), and phosphoserine aminotransferase 1 (PSAT1), exhibited increased mRNA levels. Additionally, GS deficiency appeared to upregulate the expression of glutamine transporters SLC38A2 and SLC1A5. Thus, restricting extracellular amino acids, such as glutamine, induces a stress response while promoting transcription or translation by a select group of genes, thereby facilitating cellular adaptation. However, similar to GS_WT, both GS_R324C and GS_K241R were modulated by glutamine treatment. Among GS-activity-dependent behaviors, the increased expression of numerous aminoacyl-tRNA synthetases (ARSs), which are critical for aminoacyl-tRNA biosynthesis, remains poorly understood. Most ARS-encoding genes are transcriptionally induced by activating transcription factor 4 (ATF4), the expression of which increases under oxidative stress, endoplasmic reticulum stress, hypoxia, and amino acid limitation. In GS-deficient cells, the increased expression of ATF4 was accompanied by pronounced stress caused by glutamine starvation. Thus, ARS upregulation may predominantly arise from increased ATF4 expression in GS-deficient cells. Additionally, transcriptomic analysis revealed the differential expression of specific genes, regardless of GS activity, suggesting that GS is involved in various processes other than glutamine synthesis, including angiogenesis. Although our omics study was limited to H1299 cells, in subsequent experiments, we validated our findings using additional cell lines, including Hepa1-6 and LN-229. To attain a more comprehensive understanding of the impact of the newly identified GS_K241R mutant, our investigation should be extended to various cell types and mouse models. In summary, we identified and investigated GS-deficient mutations in cancer cells and conducted an integrative transcriptomics-metabolomics analysis with comparisons to wild-type GS. This comprehensive approach provided crucial insights into the intricate pathways modulated by GS activity. Our findings advance the understanding of how GS functions in the context of reprogrammed cellular metabolism, particularly during glutamine deprivation. The altered metabolism triggered by elevated glutamate levels arising from GS mutations highlights the remarkable plasticity of cancer cell metabolism. Notably, considering the increasing research focus on GS as a potential therapeutic target in various cancer types, the findings of this study could provide innovative perspectives for drug development and the formulation of clinical treatment strategies.

An anti-neoplastic tale of metformin through its transport

Metformin is an attractive candidate drug among all the repurposed drugs for cancer. Extensive preclinical and clinical research has evaluated its efficacy in cancer therapy, revealing a mixed outcome in clinical settings. To fully exploit metformin's therapeutic potential, understanding cellular factors relevant to its transport and accumulation in cancer cells needs to be understood. This review highlights the relevance of metformin transporter status towards its anti-cancer potential. Metformin transporters are regulated at pre-transcriptional, transcriptional, and post-translational levels. Moreover, the tumour microenvironment can also influence metformin accumulation in cancer cells. Also, Metformin treatment can regulate its transporters by altering global DNA methylation, protein acetylation, and transcription factors. Importantly, metformin transporters not only influence chemotherapeutic drug toxicity but are also associated with the prognosis and survival of individuals having cancer. Strategic decisions based on the expression and regulation of metformin transporters holds promise for its therapeutic implications and relevance.

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.

SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death worldwide, but the underlying molecular mechanisms remain largely unclear. The transcription factor (TF) specificity protein 1 (SP1) plays a crucial role in the development of various cancers, including LUAD. Recent studies have indicated that master TFs may form phase-separated macromolecular condensates to promote super-enhancer (SE) assembly and oncogene expression. In this study, we demonstrated that SP1 undergoes phase separation and that its zinc finger 3 in the DNA-binding domain is essential for this process. Through Cleavage Under Targets & Release Using Nuclease (CUT&RUN) using antibodies against SP1 and H3K27ac, we found a significant correlation between SP1 enrichment and SE elements, identified the regulator of the G protein signaling 20 (RGS20) gene as the most likely target regulated by SP1 through SE mechanisms, and verified this finding using different approaches. The oncogenic activity of SP1 relies on its phase separation ability and RGS20 gene activation, which can be abolished by glycogen synthase kinase J4 (GSK-J4), a demethylase inhibitor. Together, our findings provide evidence that SP1 regulates its target oncogene expression through phase separation and SE mechanisms, thereby promoting LUAD cell progression. This study also revealed an innovative target for LUAD therapies through intervening in SP1-mediated SE formation.

Identification of a Novel hsa_circ_0058058/miR-324-5p Axis and Prognostic/Predictive Molecules for Acute Myeloid Leukemia Outcome by Bioinformatics-Based Analysis

Acute myeloid leukemia (LAML) is one of the most prevalent hematological malignancies. In recent years, while targeted approaches have shown promise in the fight against cancer, the treatability and prognosis of patients remain inadequate due to the shortage of drugs. Noncoding RNAs, especially circular RNA (circRNA) and microRNA (miRNA), have been shown to play a unique role in tumor development. This study aims to identify the disease-associated circRNA-miRNA-mRNA network by bioinformatic analysis and investigate the mechanisms in the development and progression of LAML. Additionally, it reveals the promising roles of these molecules as a diagnostic biomarker and therapeutic target for LAML treatment. Using various bioinformatics approaches, we identified the hsa_circ_0058058/miR-324-5p axis in LAML and its possible functions in LAML development. According to our results, hsa circ-0058058 can regulate the expression of AP1G1 and SP1 through miR-324-5p to support angiogenesis, the cell cycle, and DNA replication processes. Downregulation of hsa circ-0058058 may contribute to the anticancer functions of miR-324-5p on LAML tumorigenesis, and upregulation of miR-324-5p can abolish the oncogenic effects of AP1G1 and SP1 on LAML tumorigenesis. Additionally, highly enriched pathways indicated possible interactions between molecules underlying LAML pathology. Targeted molecules within this network may be able to function as therapeutic and diagnostic biomarkers for disease, while more research and clinical confirmation are needed.

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.

GBP1 promotes cutaneous squamous cell carcinoma proliferation and invasion through activation of STAT3 by SP1

Cutaneous squamous cell carcinoma (cSCC) ranks as the second most prevalent skin tumour (excluding melanoma). However, the molecular mechanisms driving cSCC progression remain elusive. This study aimed to investigate GBP1 expression in cSCC and elucidate its potential molecular mechanisms underlying cSCC development. GBP1 expression was assessed across public databases, cell lines and tissue samples. Various assays, including clone formation, CCK8 and EdU were employed to evaluate cell proliferation, while wound healing and transwell assays determined cell migration and invasion. Subcutaneous tumour assays were conducted to assess in vivo tumour proliferation, and molecular mechanisms were explored through western blotting, immunofluorescence and immunoprecipitation. Results identified GBP1 as an oncogene in cSCC, with elevated expression in both tumour tissues and cells, strongly correlating with tumour stage and grade. In vitro and in vivo investigations revealed that increased GBP1 expression significantly enhanced cSCC cell proliferation, migration and invasion. Mechanistically, GBP1 interaction with SP1 promoted STAT3 activation, contributing to malignant behaviours. In conclusion, the study highlights the crucial role of the GBP1/SP1/STAT3 signalling axis in regulating tumour progression in cSCC. These findings provide valuable insights into the molecular mechanisms of cSCC development and offer potential therapeutic targets for interventions against cSCC.

Research progress on the regulatory mechanisms of FOXC1 expression in cancers and its role in drug resistance

The Forkhead box C1 (FOXC1) transcription factor is an important member of the FOX family. After initially being identified in triple-negative breast cancer (TNBC) with significant oncogenic function, FOXC1 was subsequently demonstrated to be involved in the development of more than 16 types of cancers. In recent years, increasing studies have focused on the deregulatory mechanisms of FOXC1 expression and revealed that FOXC1 expression was regulated at multiple levels including transcriptional regulation, post-transcription regulation and post-translational modification. Moreover, dysregulation of FOXC1 is also implicated in drug resistance in various types of cancer, especially in breast cancer, which further emphasizes the translational and clinical significance of FOXC1 as a therapeutic target in cancer treatment. This review summarizes recent findings on mechanisms of FOXC1 dysregulation in cancers and its role in chemoresistance, which will help to better understand the oncogenic role of FOXC1, overcome FOXC1-mediated drug resistance and develop targeted therapy for FOXC1 in cancers.

Magnolin targeting of the JNK/Sp1/MMP15 signaling axis suppresses cervical cancer microenvironment and metastasis via microbiota modulation

Magnolin (MGL), a compound derived from the magnolia plant, has inhibitory effects on tumor cell invasion and growth. His study aims to explore the antitumor effect and underlying molecular mechanism of MGL against human cervical cancer. We found that MGL inhibited the proliferation, migration, and invasiveness of cervical cancer cells in vitro and in vivo. The underlying mechanism was shown to involve MGL-induced inhibition of JNK/Sp1-mediated MMP15 transcription and translation. Overexpression of JNK/Sp1 resulted in significant restoration of MMP15 expression and the migration and invasion capabilities of MGL-treated cervical cancer cells. MGL modulated the cervical cancer microenvironment by inhibiting cell metastasis via targeting IL-10/IL-10 receptor B (IL-10RB) expression, thereby attenuating JNK/Sp1-mediated MMP15 expression. Analysis of the gut microbiota of mice fed MGL revealed a significant augmentation in Lachnospiraceae bacteria, known for their production of sodium butyrate. In vivo experiments also demonstrated synergistic inhibition of cervical cancer cell metastasis by MGL and sodium butyrate co-administration. Our study provides pioneering evidence of a novel mechanism by which MGL inhibits tumor growth and metastasis through the IL-10/IL-10RB targeting of the JNK/Sp1/MMP15 axis in human cervical cancer cells.

Targeting of mitochondrial fission through natural flavanones elicits anti-myeloma activity

BACKGROUND

Mitochondrial alterations, often dependent on unbalanced mitochondrial dynamics, feature in the pathobiology of human cancers, including multiple myeloma (MM). Flavanones are natural flavonoids endowed with mitochondrial targeting activities. Herein, we investigated the capability of Hesperetin (Hes) and Naringenin (Nar), two aglycones of Hesperidin and Naringin flavanone glycosides, to selectively target Drp1, a pivotal regulator of mitochondrial dynamics, prompting anti-MM activity.

METHODS

Molecular docking analyses were performed on the crystallographic structure of Dynamin-1-like protein (Drp1), using Hes and Nar molecular structures. Cell viability and apoptosis were assessed in MM cell lines, or in co-culture systems with primary bone marrow stromal cells, using Cell Titer Glo and Annexin V-7AAD staining, respectively; clonogenicity was determined using methylcellulose colony assays. Transcriptomic analyses were carried out using the Ion AmpliSeq™ platform; mRNA and protein expression levels were determined by quantitative RT-PCR and western blotting, respectively. Mitochondrial architecture was assessed by transmission electron microscopy. Real time measurement of oxygen consumption was performed by high resolution respirometry in living cells. In vivo anti-tumor activity was evaluated in NOD-SCID mice subcutaneously engrafted with MM cells.

RESULTS

Hes and Nar were found to accommodate within the GTPase binding site of Drp1, and to inhibit Drp1 expression and activity, leading to hyperfused mitochondria with reduced OXPHOS. In vitro, Hes and Nar reduced MM clonogenicity and viability, even in the presence of patient-derived bone marrow stromal cells, triggering ER stress and apoptosis. Interestingly, Hes and Nar rewired MM cell metabolism through the down-regulation of master transcriptional activators (SREBF-1, c-MYC) of lipogenesis genes. An extract of Tacle, a Citrus variety rich in Hesperidin and Naringin, was capable to recapitulate the phenotypic and molecular perturbations of each flavanone, triggering anti-MM activity in vivo.

CONCLUSION

Hes and Nar inhibit proliferation, rewire the metabolism and induce apoptosis of MM cells via antagonism of the mitochondrial fission driver Drp1. These results provide a framework for the development of natural anti-MM therapeutics targeting aberrant mitochondrial dependencies.

miRNAs in the Box: Potential Diagnostic Role for Extracellular Vesicle-Packaged miRNA-27a and miRNA-128 in Breast Cancer

Circulating extracellular vesicle (EV)-derived microRNAs (miRNAs) are now considered the next generation of cancer "theranostic" tools, with strong clinical relevance. Although their potential in breast cancer diagnosis has been widely reported, further studies are still required to address this challenging issue. The present study examined the expression profiles of EV-packaged miRNAs to identify novel miRNA signatures in breast cancer and verified their diagnostic accuracy. Circulating EVs were isolated from healthy controls and breast cancer patients and characterized following the MISEV 2018 guidelines. RNA-sequencing and real-time PCR showed that miRNA-27a and miRNA-128 were significantly down-regulated in patient-derived EVs compared to controls in screening and validation cohorts. Bioinformatics analyses of miRNA-target genes indicated several enriched biological processes/pathways related to breast cancer. Receiver operating characteristic (ROC) curves highlighted the ability of these EV-miRNAs to distinguish breast cancer patients from non-cancer controls. According to other reports, the levels of EV-miRNA-27a and EV-miRNA-128 are not associated with their circulating ones. Finally, evidence from the studies included in our systematic review underscores how the expression of these miRNAs in biofluids is still underinvestigated. Our findings unraveled the role of serum EV-derived miRNA-27a and miRNA-128 in breast cancer, encouraging further investigation of these two miRNAs within EVs towards improved breast cancer detection.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.