ZEB1 induces ROS generation through directly promoting MCT4 transcription to facilitate breast cancer

SIRT6 deficiency impairs the deacetylation and ubiquitination of UHRF1 to strengthen glycolysis and lactate secretion in bladder cancer

BACKGROUND

Aberrant interplay between epigenetic reprogramming and metabolic rewiring events contributes to bladder cancer progression and metastasis. How the deacetylase Sirtuin-6 (SIRT6) regulates glycolysis and lactate secretion in bladder cancer remains poorly defined. We thus aimed to study the biological functions of SIRT6 in bladder cancer.

METHODS

Bioinformatic analysis was used to study the prognostic significance of SIRT6/UHRF1 in BLCA. Both in vitro and in vivo assays were used to determine the roles of SIRT6/UHRF1 in BLCA. Deacetylation and ubiquitin assays were performed to uncover the regulations of SIRT6-UHRF1. Measurement of extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) was used to assess glycolytic abilities.

RESULTS

Here, we show that protein deacetylase SIRT6 was down-regulated in BLCA, and predicts poor overall survival. SIRT6 deficiency notably enhances BLCA cell proliferation, self-renewal, and migration capacities in vitro and in vivo. Mechanistically, SIRT6 interacts with, deacetylates, and promotes UHRF1 degradation mediated by β-TrCP1. Thus, SIRT6 deficiency leads to stabilized UHRF1 and depends on UHRF1 to accelerate BLCA malignant progression. Furthermore, UHRF1 significantly increased aerobic glycolysis via activating MCT4/HK2 expressions. Down-regulated SIRT6 thus depended on UHRF1 to promote glycolysis and lactate secretion in BLCA. Targeting UHRF1 or MCT4 notably impaired the extracellular lactate accumulations in BLCA. Significantly, a specific small-molecule inhibitor (NSC232003) targeting UHRF1 substantially inhibited SIRT6-deficient BLCA progression.

CONCLUSION

Together, our study uncovered an epigenetic mechanism of the SIRT6/UHRF1 axis in driving BLCA glycolysis and lactate secretion, creating a novel vulnerability for BLCA treatment.

miRNAs Involvement in Modulating Signalling Pathways Involved in Ros-Mediated Oxidative Stress in Melanoma

Reactive oxygen species (ROS) are intermediates in oxidation-reduction reactions with the capacity to modify biomolecules and temporarily or permanently alter cell behaviour through signalling pathways under physiological and pathophysiological conditions where there is an imbalance between oxidative factors and the antioxidant response of the organism, a phenomenon known as oxidative stress. Evidence suggests that the differential modulation of ROS-mediated oxidative stress occurs in the pathogenesis and progression of melanoma, and that this imbalance in redox homeostasis appears to be functionally linked to microRNA (miRNA o miRs)-mediated non-mutational epigenetic reprogramming involving genes and transcription factors. The relationship between ROS-mediated stress control, tumour microenvironment, and miRNA expression in melanoma is not fully understood. The aim of this review is to analyse the involvement of miRNAs in the modulation of the signalling pathways involved in ROS-mediated oxidative stress in melanoma. It is hoped that these considerations will contribute to the understanding of the mechanisms associated with a potential epigenetic network regulation, where the modulation of oxidative stress is consolidated as a common factor in melanoma, and therefore, a potential footprint poorly documented.

The Zeb1-Cxcl1 axis impairs the antitumor immune response by inducing M2 macrophage polarization in breast cancer

Zeb1, a key epithelial-mesenchymal transition (EMT) regulator, has recently been found to be involved in M2 macrophage polarization in the tumor immune microenvironment, thereby promoting tumor development. However, the underlying mechanism of Zeb1-induced M2 macrophage polarization remains largely unexplored. To identify the potential role of Zeb1 in remodeling the tumor immune microenvironment in breast cancer, we crossed the floxed Zeb1 allele homozygously into PyMT mice to generate PyMT;Zeb1cKO (MMTV-Cre;PyMT;Zeb1fl/fl ) mice. We found that the recruitment of M2-type tumor-associated macrophages (TAMs) was significantly reduced in tumors from PyMT;Zeb1cKO mice, and their tumor suppressive effects were weakened. Mechanistically, Zeb1 played a crucial role in transcriptionally promoting the production of Cxcl1 in tumor cells. In turn, Cxcl1 activated the Cxcr2-Jak-Stat3 pathway to induce M2 polarization of TAMs in a paracrine manner, which eventually led to T-cell inactivation and impaired the antitumor immune response in breast cancer. Our results collectively revealed an important role of Zeb1 in remodeling the tumor microenvironment, suggesting a novel therapeutic intervention for the treatment of advanced breast cancer.

MCT4-driven CAF-mediated metabolic reprogramming in breast cancer microenvironment is a vulnerability targetable by miR-425-5p

Multiple oncogenic alterations contribute to breast cancer development. Metabolic reprogramming, deeply contributing to tumor microenvironment (TME) education, is now widely recognized as a hallmark of cancer. The reverse Warburg effect induces cancer-associated fibroblasts (CAFs) to produce and secrete L-lactate, enhancing malignant characteristics such as neoangiogenesis, metastatic dissemination, and treatment resistance. Monocarboxylate transporter (MCT) 4 is involved in lactate efflux from CAFs into stromal and epithelial cells. Here, we first assess the expression of miR-425-5p and its target MCT4 in breast cancer CAFs and normal fibroblasts. We analyzed the metabolic changes induced by miR-425-5p in CAFs and its role in the education of breast cancer epithelial cells. We show that miR-425-5p-induced MCT4 knockdown decreased lactate extrusion from CAFs and its availability in the TME. miR-425-5p overexpression induced profound metabolic transformation in CAFs, ultimately influencing breast cancer metabolism. Furthermore, miR-425-5p impaired the capacity of CAFs to sustain vessel formation and breast cancer cell migration, viability, and proliferation. These findings emphasize the key role of miR-425-5p in breast cancer metabolism and aggressiveness, and its possible importance for breast cancer therapy and monitoring.

Predictive toxicological effects of Artemisia absinthium essential oil on hepatic stellate cells

Medicinal plants are important worldwide, considering their properties for treating diseases; however, few studies have evaluated their toxicological potential. Among them, Artemisia absinthium is frequently used to treat liver diseases, because its essential oil has several popular therapeutic properties. Based on this information, in the present study, we investigated molecular connectors of physiological effects of the Artemisia absinthium essential oil on human hepatic stellate cell line, LX-2, to explore the potential toxicity of the plant on liver cells. LX-2 is a cellular model to investigate mechanisms of liver fibrosis; then, to analyze the essential oil effects LX-2 was cultured under different conditions, treated or not with the essential oil at 0.4 μg/μL for 24 h. Next, fluorescence microscopy analyses, gene expression measurements, and biochemical approaches revealed that the essential oil reduced pro-fibrogenic markers; however, disrupt lipid metabolism, and cause cellular stress, by the activation of cellular detoxification and pro-inflammatory processes. In conclusion, the hepatic stellate cells incubated with the essential oil present an antifibrotic potential, supporting its popular use; however, the combined results suggest that the essential oil of Artemisia absinthium should be used with caution.

Bone Marrow Mesenchymal Stem Cells Induce Metabolic Plasticity in Estrogen Receptor-Positive Breast Cancer

Cancer cells reprogram energy metabolism through metabolic plasticity, adapting ATP-generating pathways in response to treatment or microenvironmental changes. Such adaptations enable cancer cells to resist standard therapy. We employed a coculture model of estrogen receptor-positive (ER+) breast cancer and mesenchymal stem cells (MSC) to model interactions of cancer cells with stromal microenvironments. Using single-cell endogenous and engineered biosensors for cellular metabolism, coculture with MSCs increased oxidative phosphorylation, intracellular ATP, and resistance of cancer cells to standard therapies. Cocultured cancer cells had increased MCT4, a lactate transporter, and were sensitive to the MCT1/4 inhibitor syrosingopine. Combining syrosingopine with fulvestrant, a selective estrogen receptor degrading drug, overcame resistance of ER+ breast cancer cells in coculture with MSCs. Treatment with antiestrogenic therapy increased metabolic plasticity and maintained intracellular ATP levels, while MCT1/4 inhibition successfully limited metabolic transitions and decreased ATP levels. Furthermore, MCT1/4 inhibition decreased heterogenous metabolic treatment responses versus antiestrogenic therapy. These data establish MSCs as a mediator of cancer cell metabolic plasticity and suggest metabolic interventions as a promising strategy to treat ER+ breast cancer and overcome resistance to standard clinical therapies.

IMPLICATIONS

This study reveals how MSCs reprogram metabolism of ER+ breast cancer cells and point to MCT4 as potential therapeutic target to overcome resistance to antiestrogen drugs.

ZEB1-activated Notch1 promotes circulating tumor cell migration and invasion in lung squamous cell carcinoma

BACKGROUND

Lung squamous cell carcinoma (LUSC) is recognized as the major subtypes of non-small cell lung cancer (NSCLC). Circulating tumor cells (CTCs) are critical players in tumor metastasis. A molecular profiling of CTCs has previously identified notch receptor 1 (Notch1) as an important mediator in NSCLC. Therefore, we investigate Notch1 roles in LUSC and its related mechanisms.

METHODS

The serum levels of Notch1 were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The CTCs isolated from blood samples were characterized via an immunofluorescence method. Cell motion was determined using Transwell chambers. The regulatory relationship between Notch1 and zinc finger E-box-binding homeobox 1 (ZEB1) was verified by chromatin immunoprecipitation (ChIP) and luciferase reporter assays. The protein levels were detected by western blotting.

RESULTS

Higher Notch1 expression in patients with LUSC than that in normal controls was observed. Notch1 knockdown inhibited cell motion and epithelial-mesenchymal transition (EMT). ZEB1 transcriptionally activated Notch1. ZEB1 upregulation exacerbated the malignant phenotypes of CTCs.

CONCLUSION

ZEB1-activated Notch1 promotes malignant phenotypes of CTCs in LUSC and indicates poor prognosis.

A Zeb1/MtCK1 metabolic axis controls osteoclast activation and skeletal remodeling

Osteoclasts are bone-resorbing polykaryons responsible for skeletal remodeling during health and disease. Coincident with their differentiation from myeloid precursors, osteoclasts undergo extensive transcriptional and metabolic reprogramming in order to acquire the cellular machinery necessary to demineralize bone and digest its interwoven extracellular matrix. While attempting to identify new regulatory molecules critical to bone resorption, we discovered that murine and human osteoclast differentiation is accompanied by the expression of Zeb1, a zinc-finger transcriptional repressor whose role in normal development is most frequently linked to the control of epithelial-mesenchymal programs. However, following targeting, we find that Zeb1 serves as an unexpected regulator of osteoclast energy metabolism. In vivo, Zeb1-null osteoclasts assume a hyperactivated state, markedly decreasing bone density due to excessive resorptive activity. Mechanistically, Zeb1 acts in a rheostat-like fashion to modulate murine and human osteoclast activity by transcriptionally repressing an ATP-buffering enzyme, mitochondrial creatine kinase 1 (MtCK1), thereby controlling the phosphocreatine energy shuttle and mitochondrial respiration. Together, these studies identify a novel Zeb1/MtCK1 axis that exerts metabolic control over bone resorption in vitro and in vivo.

Loss of Lactate/Proton Monocarboxylate Transporter 4 Induces Ferroptosis via the AMPK/ACC Pathway and Inhibition of Autophagy on Human Bladder Cancer 5637 Cell Line

Background

Ferroptosis and autophagy have an important role in the occurrence and development of cancer, and lactate in cells and microenvironment is one of the influencing factors of ferroptosis and autophagy. The lactate/proton monocarboxylate transporter 4 (MCT4), which is expressed in the cell membrane, regulates the transport of intracellular lactic acid and lactate. The knockout of MCT4 can affect intracellular and extracellular lactic acid levels, thereby affecting the growth, proliferation, and metastasis of tumor cells via regulation of the oxidative stress in cells. However, whether MCT4 affects ferroptosis and autophagy in bladder cancer cells remains unclear.

Methods

Colony formation assay and bladder cancer xenograft animal model were used to assess the effect of MCT4 on the growth in 5637 cells. Reactive oxygen species (ROS) assay, lipid ROS assay, lipid peroxidation assay (MDA), and transmission electron microscopy were performed to assess the level of lipid peroxidation in 5637 cells. RNA-sequence, RT-PCR, and Western Blot were used to analyze the mechanism of MCT4 of ferroptosis and autophagy. AdPlus-mCherry-GFP-LC3B reporter system was used to detect the effect of MCT4 on autophagy in 5637 cells, and the effect of knockdown of MCT4 on apoptosis was analyzed by flow cytometry.

Results

The mRNA level of MCT4 was significantly upregulated in patients with bladder cancer, which was associated with a poor prognosis. In vivo and in vitro studies demonstrated that knockdown of MCT4 could inhibit the proliferation of bladder cancer cells. Furthermore, knockdown of MCT4 led to the significant increase of ROS and MDA levels in 5637 cells and ferroptosis in 5637 cells induced by ferroptosis inducers including RSL3 (APExBIO) and erastin (APExBIO) via inhibition of AMPK-related proteins. Moreover, knockdown of MCT4 inhibited autophagy in 5637 cells, while siMCT4 promoted inhibition of autophagy by CQ (an autophagy inhibitor), which increased the level of apoptosis.

Conclusion

This study confirmed that knockdown of MCT4 could affect oxidative stress and induce ferroptosis and inhibition of autophagy, thus suggesting that MCT4 may be a potential target for the treatment of bladder cancer.

Analysis of the Role and Mechanism of ZEB1 in Regulating Cervical Carcinoma Progression via Modulating PD-1/PD-L1 Checkpoint

Background

Cervical carcinoma (CC) is a common and highly malignant tumor in women. The involvement of zinc finger E-box binding homeobox 1 (ZEB1) in many kinds of tumors has been well-documented; however, its role and mechanism in CC remain to be clarified.

Objective

This study investigated the mechanism of ZEB1 in modulating the growth and metastasis of CC cells.

Methods

The expression of ZEB1 in CC tissues and adjacent normal counterparts was determined by reverse transcription-polymerase chain reaction (RT-PCR). The correlation between ZEB1 and patient clinicopathological indexes was analyzed. In vitro, gain and loss functions of ZEB1 were performed in C-33A and HeLa cell lines. The proliferation, migration, and invasion of CC cells were detected by Cell Counting Kit-8 (CCK-8) assay and transwell assay, respectively. The expression levels of apoptosis-related proteins such as BCL2-associated X (Bax), B-cell lymphoma-2 (Bcl2), and Caspase-3, as well as epithelial-mesenchymal transition (EMT)-associated proteins including E-cadherin, Vimentin, and Snail, were measured by Western blotting. In addition, the targeting relationship between ZEB1 and programmed death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) was predicted by bioinformatics and further verified by dual-luciferase reporter assay.

Results

ZEB1 was significantly up-regulated in CC tissues compared with normal counterparts. ZEB1 overexpression promoted the migration, proliferation, and invasion of CC cells and inhibited apoptosis, while knocking down ZEB1 contributed to the opposite effects. In addition, experiments on related mechanisms confirmed that ZEB1 targeted the 3'EUTR terminal of PD-1/PD-L1 and negatively regulated its expression. And an interaction between ZEB1 and PD-1/PD-L1 was identified.

Conclusion

ZEB1 can promote the proliferation and metastasis of CC cells via modulating the PD-1/PD-L1 checkpoint.