SIRT1 promotes GLUT1 expression and bladder cancer progression via regulation of glucose uptake

A systematic review on the culture methods and applications of 3D tumoroids for cancer research and personalized medicine

Cancer is a highly heterogeneous disease, and thus treatment responses vary greatly between patients. To improve therapy efficacy and outcome for cancer patients, more representative and patient-specific preclinical models are needed. Organoids and tumoroids are 3D cell culture models that typically retain the genetic and epigenetic characteristics, as well as the morphology, of their tissue of origin. Thus, they can be used to understand the underlying mechanisms of cancer initiation, progression, and metastasis in a more physiological setting. Additionally, co-culture methods of tumoroids and cancer-associated cells can help to understand the interplay between a tumor and its tumor microenvironment. In recent years, tumoroids have already helped to refine treatments and to identify new targets for cancer therapy. Advanced culturing systems such as chip-based fluidic devices and bioprinting methods in combination with tumoroids have been used for high-throughput applications for personalized medicine. Even though organoid and tumoroid models are complex in vitro systems, validation of results in vivo is still the common practice. Here, we describe how both animal- and human-derived tumoroids have helped to identify novel vulnerabilities for cancer treatment in recent years, and how they are currently used for precision medicine.

Transcriptome-Based Network Analysis Related to Histone Deacetylase Genes and Identified EMP1 as a Potential Biomarker for Prognosis in Bladder Cancer

BACKGROUND

Abnormal expression and function of histone deacetylases (HDACs) are closely associated with the development of bladder cancer (BCa). Systematic elucidation of the role of HDACs in BCa is expected to improve BCa prognosis and treatment strategies.

METHODS

We explored the correlation and expression patterns of HDAC family genes in BCa. Consensus clustering was employed to categorize BCa into subtypes based on HDAC expression profiles. Differential analysis, pathway enrichment analysis, and drug responsiveness evaluation were conducted to characterize HDAC subtypes. Then, a prognostic model based on HDAC cluster related genes was constructed and validated across multiple cohorts.

RESULTS

We identified distinct HDAC expression patterns and correlations with immune cell infiltration and enrichment of pathways in cancer, highlighting their role in BCa. Consensus clustering revealed 2 HDAC gene subtypes. Gene cluster 1 showed worse survival, higher clinical stage, and lower immune cell infiltration compared to gene cluster 2. Additionally, pathway enrichment analysis revealed differences in tumor-promoting pathways between the clusters. Moreover, gene cluster 1 exhibited higher resistance to Rho kinase inhibitor drugs. Multi-omic analysis unveiled unique mutation and CNV profiles between the clusters, indicating distinct molecular features. Furthermore, a HDAC gene-related prognostic model demonstrated robust predictive accuracy and identified EMP1 as a key prognostic gene associated with poor survival and enriched metastatic pathways.

CONCLUSION

Our study provides comprehensive insights into the landscape of HDACs in BCa, elucidating their roles in tumor heterogeneity, immune modulation, drug responsiveness, and molecular features. EMP1 is a potential therapeutic target and prognostic marker for BCa.

circ-TTC17 Promotes Esophagus Squamous Cell Carcinoma Cell Growth, Metastasis, and Inhibits Autophagy-Mediated Radiosensitivity Through miR-145-5p/SIRT1 Axis

BACKGROUND

Circular RNA (circRNA) plays a significant role in esophagus squamous cell carcinoma (ESCC) progression. Nevertheless, circ-TTC17 roles in ESCC have not fully understood.

METHODS

The levels of circ-TTC17, miR-145-5p and sirtuin 1 (SIRT1) were determined using qRT-PCR. ESCC cell functions were examined by CCK8 assay, flow cytometry, transwell assay and colony formation assay. The relative protein levels of autophagy marker and SIRT1 were determined by western blot (WB). The interactions among circ-TTC17, miR-145-5p, and SIRT1 were verified by dual-luciferase reporter assay and RIP assay.

RESULTS

circ-TTC17 was overexpressed and miR-145-5p was underexpressed in ESCC. circ-TTC17 knockdown restrained ESCC cell proliferation and metastasis, while enhance apoptosis and autophagy-mediated radiosensitivity. Circ-TTC17 could sponge miR-145-5p, and its inhibitor reversed the inhibitory effect of circ-TTC17 knockdown on ESCC cell progression. Additionally, SIRT1 was targeted by miR-145-5p, and SIRT1 overexpression abolished miR-145-5p-mediated the suppressive effect on ESCC cell progression. Also, circ-TTC17 interference reduced ESCC tumor growth via miR-145-5p/SIRT1 axis.

CONCLUSION

circ-TTC17 promoted ESCC cell growth, metastasis and inhibited autophagy-mediated radiosensitivity by miR-145-5p/SIRT1 axis.

Impacts of APOE-ε4 and exercise training on brain microvascular endothelial cell barrier function and metabolism

BACKGROUND

The APOE-ε4 genotype is the highest genetic risk factor for Alzheimer's disease (AD), and exercise training can reduce the risk of AD. Two early pathologies of AD are degradation of tight junctions between brain microvascular endothelial cells (BMEC) and brain glucose hypometabolism. Therefore, the objective of this work was to determine how the APOE-ε4 genotype and serum from exercise trained individuals impacts BMEC barrier function and metabolism.

METHODS

iPSC homozygous for the APOE-ε3 and APOE-ε4 alleles were differentiated to BMEC-like cells and used to measure barrier function and metabolism. To investigate exercise effects, serum was collected from older adults pre- and post- 6 months of exercise training (n = 9 participants per genotype). APOE-ε3 and APOE-ε4 BMEC were treated with genotype-matched serum, and then barrier function and metabolism were measured.

FINDINGS

APOE-ε4 genotype impaired BMEC barrier function and metabolism by reducing sirtuin 1 (SIRT1) levels by 27% (p = 0.0188) and baseline insulin signalling by 37% (p = 0.0186) compared to APOE-ε3 BMEC. Exercise-trained serum increased SIRT1 by 33% (p = 0.0043) in APOE-ε3 BMEC but decreased SIRT1 by 22% (p = 0.0004) in APOE ε4 BMEC.

INTERPRETATION

APOE-ε4 directly impairs glucose metabolism and barrier function. Serum from exercise trained individuals alters SIRT1 in a genotype-dependent manner but may require additional cues from exercise to decrease AD pathologies.

FUNDING

Brain and Behaviour Initiative at the University of Maryland through the Seed Grant Program, NSF-GRFP DGE 1840340, Fischell Fellowship in Biomedical Engineering, NSF CBET-2211966 and DGE-1632976, National Niemann-Pick Disease Foundation, University of Maryland ASPIRE Program, NIH R01HL165193, R01HL140239-01, and R01AG057552.

Sirtuin1 (sirt1) regulates the glycolysis pathway and decreases cisplatin chemotherapeutic sensitivity to esophageal squamous cell carcinoma

We aimed to evaluate the influence of sirtuin1 (sirt1) on the ESCC chemotherapeutic sensitivity to cisplatin. We used ESCC cell ablation sirt1 for establishing a xenograft mouse tumor model. The tumor volume was then detected. sirt1 was over-expressed significantly in ESCC patients and cells. Moreover, sirt1 knockdown raised ESCC sensitivity to cisplatin. Besides, glycolysis was associated with ESCC cell chemotherapy resistance to cisplatin. Furthermore, sirt1 increased ESCC cells' cisplatin chemosensitivity through HK2. Sirt1 enhanced in vivo ESCC chemosensitivity to cisplatin. Overall, these findings suggested that sirt1 knockdown regulated the glycolysis pathway and raised the ESCC chemotherapeutic sensitivity.

Targeting histone modifiers in bladder cancer therapy - preclinical and clinical evidence

Bladder cancer in the most advanced, muscle-invasive stage is lethal, and very limited therapeutic advances have been reported for decades. To date, cisplatin-based chemotherapy remains the first-line therapy for advanced bladder cancer. Late-line options have historically been limited. In the past few years, next-generation sequencing technology has enabled chromatin remodelling gene mutations to be characterized, showing that these alterations are more frequent in urothelial bladder carcinoma than in other cancer types. Histone modifiers have functional roles in tumour progression by modulating the expression of tumour suppressors and oncogenes and, therefore, have been considered as novel drug targets for cancer therapy. The roles of epigenetic reprogramming through histone modifications have been increasingly studied in bladder cancer, and the therapeutic efficacy of targeting those histone modifiers genetically or chemically is being assessed in preclinical studies. Results from preclinical studies in bladder cancer encouraged the investigation of some of these drugs in clinical trials, which yield mixed results. Further understanding of how alterations of histone modification mechanistically contribute to bladder cancer progression, drug resistance and tumour microenvironment remodelling will be required to facilitate clinical application of epigenetic drugs in bladder cancer.

GLUT1 inhibitor BAY-876 induces apoptosis and enhances anti-cancer effects of bitter receptor agonists in head and neck squamous carcinoma cells

Head and neck squamous cell carcinomas (HNSCCs) are cancers that arise in the mucosa of the upper aerodigestive tract. The five-year patient survival rate is ~50%. Treatment includes surgery, radiation, and/or chemotherapy and is associated with lasting effects even when successful in irradicating the disease. New molecular targets and therapies must be identified to improve outcomes for HNSCC patients. We recently identified bitter taste receptors (taste family 2 receptors, or T2Rs) as a novel candidate family of receptors that activate apoptosis in HNSCC cells through mitochondrial Ca2+ overload and depolarization. We hypothesized that targeting another component of tumor cell metabolism, namely glycolysis, may increase the efficacy of T2R-directed therapies. GLUT1 (SLC2A1) is a facilitated-diffusion glucose transporter expressed by many cancer cells to fuel their increased rates of glycolysis. GLUT1 is already being investigated as a possible cancer target, but studies in HNSCCs are limited. Examination of immortalized HNSCC cells, patient samples, and The Cancer Genome Atlas revealed high expression of GLUT1 and upregulation in some patient tumor samples. HNSCC cells and tumor tissue express GLUT1 on the plasma membrane and within the cytoplasm (perinuclear, likely co-localized with the Golgi apparatus). We investigated the effects of a recently developed small molecule inhibitor of GLUT1, BAY-876. This compound decreased HNSCC glucose uptake, viability, and metabolism and induced apoptosis. Moreover, BAY-876 had enhanced effects on apoptosis when combined at low concentrations with T2R bitter taste receptor agonists. Notably, BAY-876 also decreased TNFα-induced IL-8 production, indicating an additional mechanism of possible tumor-suppressive effects. Our study demonstrates that targeting GLUT1 via BAY-876 to kill HNSCC cells, particularly in combination with T2R agonists, is a potential novel treatment strategy worth exploring further in future translational studies.

Elucidating the role of the GC/GR/GLUT1 axis in steroid-induced osteonecrosis of the femoral head: A proteomic approach

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is a prevalent and incapacitating condition that affects the hip joint. Unfortunately, early diagnostic and treatment measures are limited.

METHODS

Our study employed Tandem Mass Tag (TMT) labeling mass spectrometry (MS)-based quantitative proteome to compare the proteins of femoral head tissues in patients with SONFH with those of patients who sustained femoral neck fracture (FNF). We investigated the level and effects of glucose transporter member 1 (GLUT1) in SONFH patients and MC3T3-E1 cells and examined the function and molecular mechanism of GLUT1 in the context of SONFH using in vivo and in vitro approaches.

RESULTS

The SONFH group exhibited significant changes in protein expression levels compared to the fracture group. Specifically, we observed the up-regulation of 86 proteins and the down-regulation of 138 proteins in the SONFH group. Among the differentially expressed proteins, GLUT1 was down-regulated and associated with glucose metabolic processes in the SONFH group. Further analysis using Parallel Reaction Monitoring (PRM), WB, and PCR confirmed that the protein was significantly down-regulated in both femoral head tissue samples from SONFH patients and dexamethasone-treated MC3T3-E1 cells. Moreover, overexpression of GLUT1 effectively reduced glucocorticoid (GC)-induced apoptosis and the suppression of osteoblast proliferation and osteogenic differentiation in MC3T3-E1 cells, as well as GC-induced femoral head destruction in GC-induced ONFH rat models. Additionally, our research demonstrated that GC down-regulated GLUT1 transcription via glucocorticoid receptors in MC3T3-E1 cells.

CONCLUSIONS

GLUT1 was down-regulated in patients with SONFH; furthermore, down-regulated GLUT1 promoted apoptosis and inhibited osteoblast ossification in dexamethasone-induced MC3T3-E1 cells and contributed to GC-induced femoral head destruction in a SONFH rat model. Glucocorticoids inhibited the transcriptional activity of GLUT1, leading to a reduction in the amount and activity of GLUT1 in the cells and ultimately promoting apoptosis and inhibiting osteoblast ossification via the GC/GR/GLUT1 axis in SONFH.

Enhanced Sampling Molecular Dynamics Simulations Reveal Transport Mechanism of Glycoconjugate Drugs through GLUT1

Glucose transporters GLUT1 belong to the major facilitator superfamily and are essential to human glucose uptake. The overexpression of GLUT1 in tumor cells designates it as a pivotal target for glycoconjugate anticancer drugs. However, the interaction mechanism of glycoconjugate drugs with GLUT1 remains largely unknown. Here, we employed all-atom molecular dynamics simulations, coupled to steered and umbrella sampling techniques, to examine the thermodynamics governing the transport of glucose and two glycoconjugate drugs (i.e., 6-D-glucose-conjugated methane sulfonate and 6-D-glucose chlorambucil) by GLUT1. We characterized the specific interactions between GLUT1 and substrates at different transport stages, including substrate recognition, transport, and releasing, and identified the key residues involved in these procedures. Importantly, our results described, for the first time, the free energy profiles of GLUT1-transporting glycoconjugate drugs, and demonstrated that H160 and W388 served as important gates to regulate their transport via GLUT1. These findings provide novel atomic-scale insights for understanding the transport mechanism of GLUT1, facilitating the discovery and rational design of GLUT1-targeted anticancer drugs.

Inhibition of glycolysis and SIRT1/GLUT1 signaling ameliorates the apoptotic effect of Leptosidin in prostate cancer cells

Since the silent information regulation 2 homolog-1 (sirtuin, SIRT1) and glucose transporter 1 (GLUT1) are known to modulate cancer cell metabolism and proliferation, the role of SIRT1/GLUT1 signaling was investigated in the apoptotic effect of Leptosidin from Coreopsis grandiflora in DU145 and PC3 human prostate cancer (PCa) cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle analysis, Western blotting, cBioportal correlation analysis, and co-immunoprecipitation were used in this work. Leptosidin showed cytotoxicity, augmented sub-G1 population, and abrogated the expression of pro-poly (ADP-ribose) polymerase (pro-PARP) and pro-cysteine aspartyl-specific protease (pro-caspase3) in DU145 and PC3 cells. Also, Leptosidin inhibited the expression of SIRT1, GLUT1, pyruvate kinase isozymes M2 (PKM2), Hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA) in DU145 and PC3 cells along with disrupted binding of SIRT1 and GLUT1. Consistently, Leptosidin curtailed lactate, glucose, and ATP in DU145 and PC3 cells. Furthermore, SIRT1 depletion enhanced the decrease of GLUT1, LDHA, and pro-Cas3 by Leptosidin in treated DU145 cells, while pyruvate suppressed the ability of Leptosidin in DU145 cells. These findings suggest that Leptosidin induces apoptosis via inhibition of glycolysis and SIRT1/GLUT1 signaling axis in PCa cells.

TIMELESS promotes reprogramming of glucose metabolism in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC), the predominant malignancy of the oral cavity, is characterized by high incidence and low survival rates. Emerging evidence suggests a link between circadian rhythm disruptions and cancer development. The circadian gene TIMELESS, known for its specific expression in various tumors, has not been extensively studied in the context of OSCC. This study aims to explore the influence of TIMELESS on OSCC, focusing on cell growth and metabolic alterations.

METHODS

We analyzed TIMELESS expression in OSCC using western blot, immunohistochemistry, qRT-PCR, and data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE). The role of TIMELESS in OSCC was examined through clone formation, MTS, cell cycle, and EdU assays, alongside subcutaneous tumor growth experiments in nude mice. We also assessed the metabolic impact of TIMELESS by measuring glucose uptake, lactate production, oxygen consumption, and medium pH, and investigated its effect on key metabolic proteins including silent information regulator 1 (SIRT1), hexokinase 2 (HK2), pyruvate kinase isozyme type M2 (PKM2), recombinant lactate dehydrogenase A (LDHA) and glucose transporter-1 (GLUT1).

RESULTS

Elevated TIMELESS expression in OSCC tissues and cell lines was observed, correlating with reduced patient survival. TIMELESS overexpression enhanced OSCC cell proliferation, increased glycolytic activity (glucose uptake and lactate production), and suppressed oxidative phosphorylation (evidenced by reduced oxygen consumption and altered pH levels). Conversely, TIMELESS knockdown inhibited these cellular and metabolic processes, an effect mirrored by manipulating SIRT1 levels. Additionally, SIRT1 was positively associated with TIMELESS expression. The expression of SIRT1, HK2, PKM2, LDHA and GLUT1 increased with the overexpression of TIMELESS levels and decreased with the knockdown of TIMELESS.

CONCLUSION

TIMELESS exacerbates OSCC progression by modulating cellular proliferation and metabolic pathways, specifically by enhancing glycolysis and reducing oxidative phosphorylation, largely mediated through the SIRT1 pathway. This highlights TIMELESS as a potential target for OSCC therapeutic strategies.

PIGT promotes cell growth, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking

BACKGROUND

Bladder cancer is very common worldwide. PIGT is a subunit of the glycosylphosphatidylinositol transamidase which involves in tumorigenesis and invasiveness. m6A modification of mRNA has been linked to cell proliferation, tumor progression and other biological events. However, how PIGT is regulated and what is the function of PIGT in bladder cancer remains to be elucidated.

METHODS

PIGT was silenced or overexpressed to study its role in regulating bladder cancer. Cell proliferation and invasion were examined with the Cell Counting Kit-8, colony formation and Transwell assay, respectively. Cellular oxygen consumption rates or extracellular acidification rates were detected by a XF24 Analyzer. Quantitative RT-PCR and immunoblots were performed to detect mRNA and protein levels.

RESULTS

PIGT was overexpressed in bladder cancer. Silencing PIGT inhibited cell proliferation, oxidative phosphorylation, and glycolysis. Overexpressing PIGT promoted cell proliferation, oxidative phosphorylation, glycolysis in vitro and tumor metastasis in vivo by activating glucose transporter 1 (GLUT1). PIGT also promoted GLUT1 glycosylation and membrane trafficking. Wilms' tumor 1-associated protein (WTAP) mediated PIGT m6A modification, and m6A reader, insulin-like growth factor 2 mRNA-binding protein (IGF2BP2), binds to the methylated PIGT to promote the stability of PIGT, leading to up-regulation of PIGT.

CONCLUSION

WTAP mediates PIGT m6A modification to increase the stability of PIGT via the IGF2BP2, which enhances cell proliferation, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking.

Discovery of Novel SIRT1/2 Inhibitors with Effective Cytotoxicity against Human Leukemia Cells

The sirtuin enzyme family members, SIRT1 and SIRT2, play both tumor-promoting and tumor-suppressing roles, depending on the context and experimental conditions. Compounds that inhibit either SIRT1 or SIRT2 show promising antitumor effects in several types of cancer models, both in vitro and in vivo. The simultaneous inhibition of SIRT1 and SIRT2 is helpful in treating cancer by completely blocking p53 deacetylation, leading to cell death. However, only a few SIRT1/2 dual inhibitors have been developed. Here, we report the discovery of a novel series of SIRT1/2 dual inhibitors via a rational drug design that involved virtual screening and a substructure search. Eleven of the derived compounds exhibited high inhibitory activities, with IC50 < 5 μM and high specificity for both SIRT1 and SIRT2. Compounds hsa55 and PS9 strongly induced apoptosis and showed antiproliferative effects against human leukemia cell lines, which could be due to their ability to increase of p53 and α-tubulin acetylation, as we observed in MOLM-13 cells. Therefore, the new scaffolds of these compounds and their efficacy in leukemia cell lines provide important clues for the further development of novel anti-leukemia drugs.

Cryopreservation Induces Acetylation of Metabolism-Related Proteins in Boar Sperm

Cryodamage affects the normal physiological functions and survivability of boar sperm during cryopreservation. Lysine acetylation is thought to be an important regulatory mechanism in sperm functions. However, little is known about protein acetylation and its effects on cryotolerance or cryodamage in boar sperm. In this study, the characterization and protein acetylation dynamics of boar sperm during cryopreservation were determined using liquid chromatography-mass spectrometry (LC-MS). A total of 1440 proteins were identified out of 4705 modified proteins, and 2764 quantifiable sites were elucidated. Among the differentially modified sites, 1252 were found to be upregulated compared to 172 downregulated sites in fresh and frozen sperms. Gene ontology indicated that these differentially modified proteins are involved in metabolic processes and catalytic and antioxidant activities, which are involved in pyruvate metabolism, phosphorylation and lysine degradation. In addition, the present study demonstrated that the mRNA and protein expressions of SIRT5, IDH2, MDH2 and LDHC, associated with sperm quality parameters, are downregulated after cryopreservation. In conclusion, cryopreservation induces the acetylation and deacetylation of energy metabolism-related proteins, which may contribute to the post-thawed boar sperm quality parameters.

The role of E3 ubiquitin ligases and deubiquitinases in bladder cancer development and immunotherapy

Bladder cancer is one of the common malignant urothelial tumors. Post-translational modification (PTMs), including ubiquitination, acetylation, methylation, and phosphorylation, have been revealed to participate in bladder cancer initiation and progression. Ubiquitination is the common PTM, which is conducted by E1 ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzyme and E3 ubiquitin-protein ligase. E3 ubiquitin ligases play a key role in bladder oncogenesis and progression and drug resistance in bladder cancer. Therefore, in this review, we summarize current knowledge regarding the functions of E3 ubiquitin ligases in bladder cancer development. Moreover, we provide the evidence of E3 ubiquitin ligases in regulation of immunotherapy in bladder cancer. Furthermore, we mention the multiple compounds that target E3 ubiquitin ligases to improve the therapy efficacy of bladder cancer. We hope our review can stimulate researchers and clinicians to investigate whether and how targeting E3 ubiquitin ligases acts a novel strategy for bladder cancer therapy.

Glucose Metabolism Reprogramming in Bladder Cancer: Hexokinase 2 (HK2) as Prognostic Biomarker and Target for Bladder Cancer Therapy

Proliferating cancer cells are able to reprogram their energy metabolism, favouring glycolysis even in the presence of oxygen and fully functioning mitochondria. Research is needed to validate the glycolysis-related proteins as prognostic/predictive biomarkers in urothelial bladder carcinoma (UBC), a malignancy tagged by high recurrence rates and poor response to chemotherapy. Here, we assessed GLUT1, HK2, PFKL, PKM2, phospho-PDH, and LDHA immunoexpression in 76 UBC samples, differentiating among urothelial, fibroblast, and endothelial cells and among normoxic versus hypoxic areas. We additionally studied the functional effects of the HK2 inhibitor 2-deoxy-D-glucose (2DG) in "in vitro" and "in vivo" preclinical UBC models. We showed that the expression of the glycolysis-related proteins is associated with UBC aggressiveness and poor prognosis. HK2 remained as an independent prognostic factor for disease-free and overall survival. 2DG decreased the UBC cell's viability, proliferation, migration, and invasion; the inhibition of cell cycle progression and apoptosis occurrence was also verified. A significant reduction in tumour growth and blood vessel formation upon 2DG treatment was observed in the chick chorioallantoic membrane assay. 2DG potentiated the cisplatin-induced inhibition of cell viability in a cisplatin-resistant subline. This study highlights HK2 as a prognostic biomarker for UBC patients and demonstrates the potential benefits of using 2DG as a glycolysis inhibitor. Future studies should focus on integrating 2DG into chemotherapy design, as an attempt to overcome cisplatin resistance.

Loss of cancer-associated fibroblast-derived exosomal DACT3-AS1 promotes malignant transformation and ferroptosis-mediated oxaliplatin resistance in gastric cancer

AIMS

Long non-coding RNAs (lncRNAs), as one of the components of exosomes derived from cancer-associated fibroblasts (CAFs), exhibit a crucial role in the pathogenesis and chemoresistance of gastric cancer (GC). Herein, we investigated the role and mechanism of a novel lncRNA disheveled binding antagonist of beta catenin3 antisense1 (DACT3-AS1) and its involvement in GC.

METHODS

DACT3-AS1 was identified by RNA-sequencing and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The functional role of DACT3-AS1 in GC was evaluated using in vitro and in vivo experiments including Transwell assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay, immunoblotting, and xenograft tumor mouse model. Dual-luciferase reporter assay was performed to assess the association between genes.

RESULTS

DACT3-AS1 was downregulated and involved in poor prognosis of patients with GC. The results from both in vitro and in vivo experiments showed that DACT3-AS1 suppressed cell proliferation, migration, and invasion through targeting miR-181a-5p/sirtuin 1 (SIRT1) axis. Additionally, DACT3-AS1 was transmitted from CAFs to GC cells mainly via exosomes. Exosomal DACT3-AS1 alleviated xenograft tumor growth. DACT3-AS1 conferred sensitivity of cancer cells to oxaliplatin through SIRT1-mediated ferroptosis both in vitro and in vivo.

CONCLUSIONS

CAFs-derived exosomal DACT3-AS1 is a suppressive regulator in malignant transformation and oxaliplatin resistance. DACT3-AS1 could be used for diagnosis and treatment of GC.

A Novel Glycolysis-Related Gene Signature Predicts Prognosis For Cutaneous Melanoma

BACKGROUND

There exists a lack of effective tools predicting prognosis for cutaneous melanoma patients. Glycolysis plays an essential role in the carcinogenesis process.

OBJECTIVE

We intended to construct a new prognosis model for cutaneous melanoma.

METHODS

Based on the data from the TCGA database, we conducted a univariate Cox regression analysis and identified prognostic glycolysis-related genes (GRGs). Meanwhile, the GSE15605 dataset was used to identify differentially expressed genes (DEGs). The intersection of prognostic GRGs and DEGs was extracted for the subsequent multivariate Cox regression analysis.

RESULTS

A prognostic signature containing ten GRGs was built, and the TCGA cohort was classified into high and low risk subgroups based on the risk score of each patient. K-M analysis manifested that the overall survival of the high-risk group was statistically worse than that of the lowrisk group. Further study indicated that the risk-score could be used as an independent prognostic factor that effectively predicted the clinical prognosis in patients of different ages, genders, and stages. GO and KEGG enrichment analysis showed DEGs between high and low risk groups were enriched in immune-related functions and pathways. In addition, a significant difference existed between high and low risk groups in infiltration pattern of immune cells and expression levels of inhibitory immune checkpoint genes.

CONCLUSION

A new glycolysis-related gene signature was established for identifying cutaneous melanoma patients with poor prognoses and formulating individualized treatment.

O-GlcNAcylation and stablization of SIRT7 promote pancreatic cancer progression by blocking the SIRT7-REGγ interaction

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and its dismal prognosis indicates the urgent need to elucidate the potential oncogenic mechanisms. SIRT7 is a classic NAD+-dependent deacetylase that stabilizes the transformed state of cancer cells. However, its functional roles in PDAC are still unclear. Here, we found that SIRT7 expression is upregulated and predicts poor prognosis in PDAC. Then we screened the new interacting proteins of SIRT7 by mass spectrometry and the results showed that SIRT7 can interact with O-GlcNAc transferase (OGT). O-GlcNAcylation stabilizes the SIRT7 protein by inhibiting its interaction with REGγ to prevent degradation, and hyper-O-GlcNAcylation in pancreatic cancer cells leads to hypoacetylation of H3K18 via SIRT7, which promotes transcriptional repression of several tumour suppressor genes. In addition, SIRT7 O-GlcNAcylation at the serine 136 residue (S136) is required to maintain its protein stability and deacetylation ability. In vivo and in vitro experiments showed that blocking SIRT7 O-GlcNAcylation at S136 attenuates tumour progression. Collectively, we demonstrate that O-GlcNAcylation is an important post-translational modification of SIRT7 in pancreatic cancer cells, and elucidating this mechanism of SIRT7 is expected to pave the way for the development of novel therapeutic methods in the future.

Virtual Screening in the Identification of Sirtuins’ Activity Modulators

Sirtuins are NAD⁺-dependent deac(et)ylases with different subcellular localization. The sirtuins’ family is composed of seven members, named SIRT-1 to SIRT-7. Their substrates include histones and also an increasing number of different proteins. Sirtuins regulate a wide range of different processes, ranging from transcription to metabolism to genome stability. Thus, their dysregulation has been related to the pathogenesis of different diseases. In this review, we discussed the pharmacological approaches based on sirtuins’ modulators (both inhibitors and activators) that have been attempted in in vitro and/or in in vivo experimental settings, to highlight the therapeutic potential of targeting one/more specific sirtuin isoform(s) in cancer, neurodegenerative disorders and type 2 diabetes. Extensive research has already been performed to identify SIRT-1 and -2 modulators, while compounds targeting the other sirtuins have been less studied so far. Beside sections dedicated to each sirtuin, in the present review we also included sections dedicated to pan-sirtuins’ and to parasitic sirtuins’ modulators. A special focus is dedicated to the sirtuins’ modulators identified by the use of virtual screening.

Glucose transporters: Important regulators of endometrial cancer therapy sensitivity

Glucose is of great importance in cancer cellular metabolism. Working together with several glucose transporters (GLUTs), it provides enough energy for biological growth. The main glucose transporters in endometrial cancer (EC) are Class 1 (GLUTs 1-4) and Class 3 (GLUTs 6 and 8), and the overexpression of these GLUTs has been observed. Apart from providing abundant glucose uptake, these highly expressed GLUTs also participate in the activation of many crucial signaling pathways concerning the proliferation, angiogenesis, and metastasis of EC. In addition, overexpressed GLUTs may also cause endometrial cancer cells (ECCs) to be insensitive to hormone therapy or even resistant to radiotherapy and chemoradiotherapy. Therefore, GLUT inhibitors may hopefully become a sensitizer for EC precision-targeted therapies. This review aims to summarize the expression regulation, function, and therapy sensitivity of GLUTs in ECCs, aiming to provide a new clue for better diagnosis and treatment of EC.

SIRT1 regulated hexokinase-2 promoting glycolysis is involved in hydroquinone-enhanced malignant progression in human lymphoblastoid TK6 cells

Reprogramming of cellular metabolism is a vital event during tumorigenesis. The role of glycolysis in malignant progression promoted by hydroquinone (HQ), one of the metabolic products of benzene, remains to be understood. Recently, we reported the overexpression of sirtuin 1 (SIRT1) in HQ-enhanced malignant progression of TK6 cells and hypothesized that SIRT1 might contribute to glycolysis and favor tumorigenesis. Our data showed that acute exposure of TK6 cells to HQ for 48 h inhibited glycolysis, as indicated by reduction in glucose consumption, lactate production, hexokinase activity, and the expression of SIRT1 and glycolytic enzymes, including HIF-1α, hexokinase-2 (HK-2), ENO-1, glucose transporter 1 (Glut-1), and lactic dehydrogenase A (LDHA). Knockdown of SIRT1 or inhibition of glycolysis using the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) downregulated the levels of SIRT1 and glycolytic enzymes and significantly enhanced HQ-induced cell apoptosis, although knockdown of SIRT1 or 2-DG alone had little effect on apoptosis. Furthermore, immunofluorescence and Co-IP assays demonstrated that SIRT1 regulated the expression of HK-2, and HQ treatment caused a decrease in SIRT1 and HK-2 binding to mitochondria. Importantly, we found that glycolysis was promoted with increasing HQ treatment weeks. Long-term HQ exposure increased the expression of SIRT1 and several glycolytic enzymes and promoted malignant cell progression. Moreover, compared with the PBS group, glucose consumption and lactate production increased after 10 weeks of HQ exposure, and the protein levels of SIRT1 and HK-2 were increased after 15 weeks of HQ exposure, while those of Glut-1, ENO-1, and LDHA were elevated. In addition, SIRT1 knockdown HQ 19 cells exhibited decreased lactate production, glucose consumption, glycolytic enzymes expression, cell growth, and tumor formation in nude mice. Our findings identify the high expression of SIRT1 as a strong oncogenic driver that positively regulates HK-2 and promotes glycolysis in HQ-accelerated malignant progression of TK6 cells.

CNN1 Represses Bladder Cancer Progression and Metabolic Reprogramming by Modulating HIF-1α Signaling Pathway

Bladder cancer (BC) is the second most common urinary system malignant tumor around the whole world. It has been reported that CNN1 was lowly expressed in BC tissues. However, the mechanisms of CNN1 on BC cells were unclear. Herein, we aimed to probe the specific influences of CNN1 on BC pathogenesis. First, the expression level and prognostic ability of CNN1 in BC patients were surveyed. Then, CNN1 overexpression was executed to exhibit the influences of CNN1 on BC cells. The real-time PCR and Western blotting were employed to detect by the mRNA and protein expression levels. CCK8 assay was utilized to examine cell proliferation, and transwell assay was executed to test cell invasion and migration. The corresponding kits were utilized to detect glucose absorption, lactate secretion, and ATP level. BC cells overexpressing CNN1 were utilized to establish a nude mouse xenograft tumor model, and the tumor volume and tumor weight were detected. Nude mouse tumor tissues were used for immunohistochemical experiments to test the expression levels of Ki-67 and CNN1. The outcomes indicated that CNN1 was significantly lowly expressed in BC tissues and cells. Besides, low expression of CNN1 might be concerned with poor prognosis. Moreover, overexpression of CNN1 repressed the proliferation, invasion, and migration of BC cells. Furthermore, CNN1 overexpression decreased the protein levels of glycolysis-related protein GLUT1 (glucose transporter 1), pyruvate kinase M2 (PKM2), and LDHA (lactate dehydrogenase A). Then, the decreased mRNA and protein levels of HIF-1α and PDK1 were identified after CNN1 overexpression. The in vivo assays verified the effects of aberrant expression of CNN1 in mice with BC. In conclusion, these findings suggested that CNN1 might modulate BC progression through activating HIF-1α pathway and CNN1 might be a promising marker for BC diagnosis.

Low-dose arsenic trioxide enhances membrane-GLUT1 expression and glucose uptake via AKT activation to support L-02 cell aberrant proliferation

Long term low dose exposure of arsenic has been reported to lead various cells proliferation and malignant transformation. GLUT1, as the key transporter of glucose, has been reported to have association with rapid proliferation of various cells or tumor cells. In our study, we found that low dose exposure to arsenic trioxide (0.1μmol/L As₂O₃) could induce an increase in glucose uptake and promote cell viability and DNA synthesis. And, 2-DG, a non-metabolized glucose analog, significantly decreased the glucose uptake and cell proliferation of 0.1μmol/L As₂O₃ treated L-02 cells. However, 4 mmol/L 2-DG was co-utilized with equal dose glucose had no significant effect on the cell proliferation of 0.1μmol/L As₂O₃ treated L-02 cells. Further studies showed that exposure to 0.1μmol/L As₂O₃ could promote the expression of GLUT1 on plasma membrane. Inhibition of GLUT1 expression by 5μmol/L BAY-876 significantly decreased the abilities of glucose uptake and cell proliferation in As₂O₃-treated L-02 cells. Moreover, 0.1μmol/L As₂O₃ induced the AKT activation indicated by increased the phospho-AKT (Ser473 and Thr308). Knockdown AKT by shRNA or inhibited AKT activation by LY294002 was followed by significantly decreased glucose uptake, GLUT1 plasma membrane expression and cell proliferation in As₂O₃-treated L-02 cells. All in all, these results demonstrated that arsenic trioxide-induced AKT activation contributed to the cells proliferation through upregulating expression of GLUT1 on plasma membrane that enhanced glucose uptake.

Metformin alleviates the cognitive impairment caused by aluminum by improving energy metabolism disorders in mice

Long-term exposure to environmental aluminum was found to be related to the occurrence and development of neurodegenerative diseases. Energy metabolism disorders, one of the pathological features of neurodegenerative diseases, may occur in the early stage of the disease and are of potential intervention significance. Here, sub-chronic aluminum exposure mouse model was established, and metformin was used to intervene. We found that sub-chronic aluminum exposure decreased the protein levels of phosphorylation AMPK (p-AMPK), glucose transporter 1 (GLUT1) and GLUT3, taking charge of glucose uptake in the brain, reduced the levels of lactate shuttle-related proteins monocarboxylate transporter 4 (MCT4) and MCT2, as well as lactate content in the cerebral cortex, while increased hypoxia-inducible factor-1α (HIF-1α) level to drive downstream pyruvate dehydrogenase kinase 1 (PDK1) expression, thereby inhibiting pyruvate dehydrogenase (PDH) activity, and ultimately led to ATP depletion, neuronal death, and cognitive dysfunction. However, metformin could rescue these injuries. Thus, it came to a conclusion that aluminum could damage glucose uptake, interfere with astrocyte-neuron lactate shuttle (ANLS), interrupt the balance in energy metabolism, and resulting in cognitive function, while metformin has a neuroprotective effect against the disorder of energy metabolism caused by aluminum in mice.

Clinical value of SIRT1 as a prognostic biomarker in esophageal squamous cell carcinoma, a systematic meta-analysis

Several studies reported that the expression of SIRT1 was associated with the clinical features of patients with esophageal squamous cell carcinoma (ESCC), but the function remains inconsistent. We conducted this study to illustrate the clinical value of SIRT1 expression in the early diagnosis and prediction of prognosis of ESCC. In this study, PubMed, Embase, and Web of Science were searched by two independent researchers and STATA14.0 software was used to conduct meta-analysis. The odds ratio with 95% confidence interval was used to estimate the pooled effect. Egger's test and Begg's funnel were used to assess publication bias. Sensitivity analysis was used to evaluate the reliability and stability of meta-analysis results. According to the inclusion and exclusion criteria, six studies were enrolled, including 811 cases of ESCC. Results of the meta-analysis indicated that SIRT1 was overexpressed in ESCC and the SIRT1 expression was closely related to the clinicopathological features of ESCC, such as tumor infiltration, tumor node metastasis (TNM) stage, and lymph node metastasis. In the survival analysis, high expression of SIRT1 represented a poor prognosis in ESCC patients. Our study demonstrated that SIRT1 was overexpressed in ESCC, and it might be a potential biomarker for progress of ESCC.

TRIM38 triggers the uniquitination and degradation of glucose transporter type 1 (GLUT1) to restrict tumor progression in bladder cancer

BACKGROUND

Loss-of-function mutations or abnormal expressions of E ubiquitin ligases contributes to tumorigenesis. TRIM38 was reported to regulate immunity, inflammatory responses or apoptosis, but its roles in tumor progression remain inconclusive. This study aimed to investigate the functional roles of TRIM38 in bladder cancer to identify effective targets.

METHODS

Firstly, the expression data of ubiquitination-associated genes were derived from the TCGA-BLCA cohort. Univariate Cox regression method was utilized to screen prognostic genes. Colony formation assay, Transwell assay, sphere formation assays were used to assess functional roles of TRIM38. TAP/MS assay was used to identify downstream substrates of TRIM38. Fresh clinical BLCA tissues were collected to evaluate the clinicopathological features of patients with different TRIM38 expression. The subcutaneous tumor models were established to determine the drug efficacy of BAY-876.

RESULTS

A list of ubiquitination-associated signature was identified based on the screening in TCGA-BLCA cohort. Subsequent validations revealed that TRIM38 was a significant suppressor in tumors, which was expressed lowly in BLCA. Kaplan-Meier analysis and correlation analysis suggested that patients with low TRIM38 expressions had shorter survival time and advanced clinical characteristics. Targeting TRIM38 reinforced BLCA cells proliferation, migration and stemness. Mechanistically, TRIM38 interacted with GLUT1, thereby promoting its ubiquitinoylation and degradation. Furthermore, TRIM38 deficiency relied on accumulated GLUT1 proteins to enhance BLCA malignant features and cellular glycolytic capacity. We accordingly investigated the efficacy of GLUT1 inhibitor (BAY-876) in BLCA and determined its IC50 values across cell lines. Tumor xenograft models further validated that BAY-876 could effectively suppress the in vivo growth of TRIM38^low/- BLCA.

CONCLUSIONS

Our results suggested that TRIM38 plays a tumor suppressive role in BLCA pathogenesis and TRIM38/GLUT1 axis is a therapeutic vulnerability for clinical treatment, which possessing great translational significance.

Sirtuin Modulators in Cellular and Animal Models of Human Diseases

Sirtuins use NAD⁺ to remove various acyl groups from protein lysine residues. Through working on different substrate proteins, they display many biological functions, including regulation of cell proliferation, genome stability, metabolism, and cell migration. There are seven sirtuins in humans, SIRT1-7, each with unique enzymatic activities, regulatory mechanisms, subcellular localizations, and substrate scopes. They have been indicated in many human diseases, including cancer, neurodegeneration, microbial infection, metabolic and autoimmune diseases. Consequently, interests in development of sirtuin modulators have increased in the past decade. In this brief review, we specifically summarize genetic and pharmacological modulations of sirtuins in cancer, neurological, and cardiovascular diseases. We further anticipate this review will be helpful for scrutinizing the significance of sirtuins in the studied diseases.

SRT1720 inhibits the growth of bladder cancer in organoids and murine models through the SIRT1-HIF axis

There are unmet clinical needs for novel therapeutic targets and drugs for bladder cancer. Majority of previous work relied on limited bladder cancer cell lines, which could not well represent the tumor heterogeneity and pathology of this disease. Recently, it has been shown that cancer organoids can recapitulate pathological and molecular properties of bladder cancer. Here, we report, by our knowledge, the first bladder cancer organoid-based small molecule screening for epigenetic drugs. We found that SRT1720, a Sirtuin 1 (SIRT1) activator, significantly inhibits the growth of both mouse and human bladder cancer organoids. And it also restrains the development of mouse in situ bladder cancer and human PDX bladder cancer. Mutation of Sirt1 promotes the growth of cancer organoids and decreases their sensitivity to SRT1720, which validate Sirt1 as the target of SRT1720 in bladder cancer. Mechanistically, SRT1720 treatment represses the hypoxia pathway through deacetylating HIF1α by activating Sirt1. Genetic or pharmaceutic inhibitions of HIF mimic the anti-tumor effect of SRT1720. Furthermore, the SIRT1-repressed gene signature is associated with the hypoxia target gene signature and poor prognosis in human bladder cancers. Thus, our study demonstrates the power of cancer organoid-based drug discovery and, in principle, identifies SRT1720 as a new treatment for bladder cancer.

Chitosan-Based Glycolipid Conjugated siRNA Delivery System for Improving Radiosensitivity of Laryngocarcinoma

Glucose Transporter-1 (GLUT-1) is considered to be a possible intrinsic marker of hypoxia in malignant tumors, which is an important factor in radioresistance of laryngocarcinoma. We speculated that the inhibition of GLUT-1 expression might improve the radiosensitivity of laryngocarcinoma. GLUT-1 siRNA was designed to inhibit the GLUT-1 expression, but the high molecular weight and difficult drug delivery limited the application. Herein, we constructed a glycolipid polymer chitosan oligosaccharide grafted stearic acid (CSSA) to conjugate siRNA via electrostatic interaction. The characteristics of CSSA and CSSA/siRNA were studied, as well as the radiosensitization effect of siRNA on human laryngocarcinoma epithelial (Hep-2) cells. Compared with the traditional commercial vector LipofectamineTM2000 (Lipo), CSSA exhibited lower cytotoxicity, more efficiently cellular uptake. Incubating with CSSA/siRNA, the survival rates of Hep-2 cells were significantly decreased comparing with either the group before transfection or Lipo/siRNA. CSSA is a promising carrier for efficient siRNA delivery and radiosensitization of laryngocarcinoma.

HBXIP accelerates glycolysis and promotes cancer angiogenesis via AKT/mTOR pathway in bladder cancer

Abnormal metabolism and uncontrolled angiogenesis are two important characteristics of malignant tumors. Although HBXIP is known to be associated with a poor prognosis for bladder cancer (BC), its effects on glycolysis and angiogenesis in BC have not been investigated. BC prognosis and relative gene expression of HBXIP were analyzed using the GEPIA, UALCAN, and STRING databases. BC cell angiogenesis and glycolysis were assessed by vasculogenic mimicry and glycolysis assay. Human umbilical vein endothelial cell (HUVEC) viability, migration, and angiogenesis were assessed by CCK8, transwell, wound healing, and tube formation assays. The results showed that HBXIP was highly expressed in BC tissues and cells. Knockdown of HBXIP expression decreased the levels of glucose uptake, lactate production, and glycolytic enzyme expression in BC cells, and decreased cell viability and migration of HUVECs. Additionally, silencing HBXIP reduced the total length of tubes and number of intersections, and EPO and VEGF protein expression in BC cells and HUVECs. Furthermore, knockdown of HBXIP expression reversed cell viability, migration, tube formation, and vasculogenic mimicry under high glucose and lactate conditions. Mechanistically, silencing of HBXIP reduced the protein expression levels of pAKT-ser473 and pmTOR, and inhibition of HBXIP, AKT, and mTOR expression decreased glycolytic enzyme protein expression. Our findings suggest that HBXIP reduces glycolysis in BC cells via regulation of AKT/mTOR signaling, thereby blocking BC angiogenesis. Collectively, this study provides a potential strategy to target HBXIP and AKT/mTOR for regulating glycolysis progression concurrently with anti-angiogenesis effects, and thereby develop novel therapeutics for the treatment of BC.

lncRNA GAS6-AS1 inhibits progression and glucose metabolism reprogramming in LUAD via repressing E2F1-mediated transcription of GLUT1

Glucose metabolism reprogramming is one of the hallmarks of cancer cells, although functional and regulatory mechanisms of long noncoding RNA (lncRNA) in the contribution of glucose metabolism in lung adenocarcinoma (LUAD) remain incompletely understood. The aim of this study was to uncover the role of GAS6-AS1 in the regulation of progression and glucose metabolism in LUAD. We discovered that overexpression of GAS6-AS1 suppressed tumor progression of LUAD both in vitro and in vivo. Metabolism-related assays revealed that GAS6-AS1 inhibited glucose metabolism reprogramming. Mechanically, GAS6-AS1 was found to repress the expression of glucose transporter GLUT1, a key regulator of glucose metabolism. Ectopic expression of GLUT1 restored the inhibition effect of GAS6-AS1 on cancer progression and glucose metabolism reprogramming. Further investigation identified that GAS6-AS1 directly interacted with transcription factor E2F1 and suppressed E2F1-mediated transcription of GLUT1, and GAS6-AS1 was downregulated in LUAD tissues and correlated with clinicopathological characteristics and survival of patients. Taken together, our results identified GAS6-AS1 as a novel tumor suppressor in LUAD and unraveled its underlying molecular mechanism in reprogramming glucose metabolism. GAS6-AS1 potentially may serve as a prognostic marker and therapeutic target in LUAD.

Targeting Sirtuin 1 signaling pathway by ginsenosides

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng is a kind of traditional Chinese herbal medicine, known as "king of herbs" and widely used in China, South Korea, and other Asian countries. Ginsenosides are one of active components of Panax ginseng Meyer, which have many pharmacological effects, such as enhancing memory, improving immunity and cardiovascular system, delaying aging, and preventing cancer.

AIMS OF THE REVIEW

This review aims to summarize the recent findings for ginsenosides targeting Sirtuin 1 (SIRT1) signaling pathway for the prevention and treatment of a series of diseases.

MATERIALS AND METHODS

An up-to-August 2020 search was carried out in databases such as PubMed, ScienceDirect, Google Scholar, China National Knowledge Infrastructure, and classic books of traditional Chinese medicine using the keywords: "SIRT1", and/or paired with "ginseng", and "ginsenosides".

RESULTS

SIRT1 is a class-III histone deacetylase (HDAC), a nicotinamide adenine dinucleotide (NAD⁺)-dependent enzyme, which is deeply involved in a series of pathological processes. Based on specific intracellular localization, SIRT1 has various cytoplasmic and nuclear targets and plays a potential role in energy metabolism, oxidative stress, inflammation, tumorigenesis, and aging. Ginsenosides are generally classified into three groups and microbially transformed to final metabolites. Among of them, most ginsenosides have been reported as SIRT1 activators, especially those ginsenosides with two glucopyranosyl groups on the C-3 position. Importantly, many ginsenosides can be used to prevent and treat oxidative stress, inflammation, aging, tumorigenesis, depression, and others by targeting SIRT1 signaling pathway.

CONCLUSIONS

This paper reviews recent evidences of ginsenosides targeting SIRT1 for the first time, which could provide new insights on the preclinical and clinical researches for ginsenosides against multiple disorders.

A positive feedback loop between TAZ and miR-942-3p modulates proliferation, angiogenesis, epithelial-mesenchymal transition process, glycometabolism and ROS homeostasis in human bladder cancer

Background

Transcriptional coactivator with PDZ-binding motif (TAZ) has been reported to be involved in tumor progression, angiogenesis, epithelial-mesenchymal transition (EMT), glycometabolic modulation and reactive oxygen species (ROS) buildup. Herein, the underlying molecular mechanisms of the TAZ-induced biological effects in bladder cancer were discovered.

Methods

qRT-PCR, western blotting and immunohistochemistry were performed to determine the levels of TAZ in bladder cancer cells and tissues. CCK-8, colony formation, tube formation, wound healing and Transwell assays and flow cytometry were used to evaluate the biological functions of TAZ, miR-942-3p and growth arrest-specific 1 (GAS1). QRT-PCR and western blotting were used to determine the expression levels of related genes. Chromatin immunoprecipitation and a dual-luciferase reporter assay were performed to confirm the interaction between TAZ and miR-942. In vivo tumorigenesis and colorimetric glycolytic assays were also conducted.

Results

We confirmed the upregulation and vital roles of TAZ in bladder cancer. TAZ-induced upregulation of miR-942-3p expression amplified upstream signaling by inhibiting the expression of large tumor suppressor 2 (LATS2, a TAZ inhibitor). MiR-942-3p attenuated the impacts on cell proliferation, angiogenesis, EMT, glycolysis and ROS levels induced by TAZ knockdown. Furthermore, miR-942-3p restrained the expression of GAS1 to modulate biological behaviors.

Conclusion

Our study identified a novel positive feedback loop between TAZ and miR-942-3p that regulates biological functions in bladder cancer cells via GAS1 expression and illustrated that TAZ, miR-942-3p and GAS1 might be potential therapeutic targets for bladder cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01846-5.

CircHIPK3 Alleviates High Glucose Toxicity to Human Renal Tubular Epithelial HK-2 Cells Through Regulation of miR-326/miR-487a-3p/SIRT1

BACKGROUND

The intervention of circular RNA HIPK3 (circHIPK3) in diabetes has drawn increasing attention in recent years. However, the underlying mechanism of circHIPK3 in diabetic nephropathy (DN) has not been fully elucidated. Thus, the current study aims to investigate the role of circHIPK3 in high glucose (HG)-induced toxicity to human renal tubular epithelial HK-2 cells.

METHODS

The expression of circHIPK3 in HK-2 cells induced by HG was determined by qRT-PCR and Western blot. The regulatory effects of circHIPK3 and miR-326/miR-487a-3p on cells proliferative and apoptosis were evaluated by CCK-8 and flow cytometry. Dual-luciferase reporter assay was applied to predict the target genes of miR-326 or miR-487a-3p.

RESULTS

Expression level of circHIPK3 in HK-2 cells was remarkably decreased after the treatment of HG. The overexpression of circHIPK3 effectively reversed the HG-induced HK-2 cell proliferation inhibition and apoptosis. Furthermore, SIRT1 was confirmed to be the target gene of miR-326 and miR-487a-3p, which were showed to be the downstream genes of circHIPK3. The silencing of miR-326 or miR-487a-3p was also proved to induce proliferation and reduce apoptosis in HG-induced HK-2 cells.

CONCLUSION

Our data suggest that overexpression of circHIPK3 can attenuate the proliferation inhibition of HK-2 induced by HG and inhibit apoptosis through sponging miR-326 or miR-487a-3p to regulate SIRT1.

LINC00839 Regulates Proliferation, Migration, Invasion, Apoptosis and Glycolysis in Neuroblastoma Cells Through miR-338-3p/GLUT1 Axis

BACKGROUND

Long noncoding RNAs (lncRNAs) are related to the development and treatment of neuroblastoma. The lncRNA LINC00839 is dysregulated in neuroblastoma, while its function and mechanism in neuroblastoma development remain largely unclear.

METHODS

The tumor and adjacent noncancerous tissues were collected from 48 neuroblastoma patients. LINC00839, glucose transporter 1 (GLUT1) and microRNA-338-3p (miR-338-3p) abundances were examined via quantitative reverse transcription polymerase chain reaction or Western blot. Cell proliferation, apoptosis, migration, invasion and glycolysis were assessed via Cell Counting Kit-8, colony formation, flow cytometry, wound healing, transwell, glucose uptake and lactate production. The target relationship of miR-338-3p and LINC00839 or GLUT1 was tested via dual-luciferase reporter analysis and RNA immunoprecipitation. The function of LINC00839 on neuroblastoma cell growth in vivo was tested via a xenograft model.

RESULTS

LINC00839 and GLUT1 abundances were increased in neuroblastoma tissues and cell lines. The high expression of LINC00839 and GLUT1 indicated the lower overall survival. LINC00839 interference constrained neuroblastoma cell proliferation, migration, invasion and glycolysis, and facilitated apoptosis. GLUT1 overexpression or miR-338-3p knockdown could mitigate the influence of LINC00839 silence on neuroblastoma cell processes. LINC00839 could regulate GLUT1 expression via miR-338-3p. LINC00839 knockdown reduced neuroblastoma cell growth in xenograft model.

CONCLUSION

LINC00839 silence repressed neuroblastoma cell proliferation, migration, invasion and glycolysis and promoted apoptosis via regulating miR-338-3p/GLUT1 axis.

Upregulated GRB7 promotes proliferation and tumorigenesis of Bladder Cancer via Phospho-AKT Pathway

Growth factor receptor-bound protein 7 (GRB7) has been found closely related to the occurrence and development of various tumors, but its function in bladder cancer has not yet been elucidated. The study is aiming at investigating the expression and function of GRB7 in bladder cancer. The Cancer Genome Atlas (TCGA) database was selected to analyze mRNA levels of GRB7 in bladder cancer. RT-qPCR and Western blot were conducted to detect the expression of GRB7 in normal bladder epithelial cells, seven bladder cancer cell lines and eight pairs of malignant/nonmalignant bladder tissues. The role of GRB7 in tumor proliferation and tumorigenesis was explored by establishing stable cells, in vitro cell experiments and in vivo xenograft models. The molecular regulation mechanism of GRB7 in bladder cancer was investigated by treatment with AKT inhibitor. GRB7 mRNA was upregulated in bladder cancer samples compared with that in normal tissue samples. Overexpressing GRB7 significantly promoted the proliferation and tumorigenesis of bladder cancer. However, silencing GRB7 played the retarding part. GRB7 promoted G1/S transition by activating the AKT pathway. Our results indicate that GRB7 plays an important role in promoting proliferation and tumorigenesis of bladder cancer.

Fluoride Compromises Testicular Redox Sensor, Gap Junction Protein, and Metabolic Status: Amelioration by Melatonin

The excess fluoride intake has been shown to adversely affect male reproductive health. The aim of the present study was to investigate the key mechanism underlying fluoride-induced testicular dysfunction and the role of melatonin as a modulator of testicular metabolic, oxidative, and inflammatory load. The present results indicated that sodium fluoride (NaF) exposure to adult male golden hamsters severely impairs reproductive physiology as evident from markedly reduced sperm count/viability, testosterone level, androgen receptor (AR), testicular glucose transporter (GLUT-1), gap junction (connexin-43), and survival (Bcl-2) protein expression. NaF exposure markedly increased testicular oxidative load, inflammatory (NF-kB/COX-2), and apoptotic (caspase-3) protein expression. However, melatonin treatment remarkably restored testicular function as evident by normal histoarchitecture, increased sperm count/viability, enhanced antioxidant enzyme activities (SOD and Catalase), and decreased lipid peroxidation (LPO) level. In addition, melatonin treatment upregulated testicular Nrf-2/HO-I, SIRT-1/ FOXO-1, and downregulated NF-kB/COX-2 expression. Further, melatonin ameliorated NaF-induced testicular metabolic stress by modulating testicular GLUT-1expression, glucose level, and LDH activity. Furthermore, melatonin treatment enhanced testicular PCNA, Bcl-2, connexin-43, and reduced caspase-3 expression. In conclusion, we propose the molecular mechanism of fluoride-induced testicular damages and ameliorative action(s) of melatonin.

Long noncoding RNA HULC accelerates the growth of human liver cancer stem cells by upregulating CyclinD1 through miR675-PKM2 pathway via autophagy

BACKGROUND

The functions of HULC have been demonstrated in several cancers. However, its mechanism has not been elucidated in human liver cancer stem cells.

METHODS

Liver cancer stem cells were isolated from Huh7 cells; gene infection and tumorigenesis test in vitro and in vivo were performed.

RESULTS

We demonstrate that HULC promotes growth of liver cancer stem cells in vitro and in vivo. Mechanistically, HULC enhances the expression of Sirt1 dependent on miR675 and then induces the cellular autophagy through Sirt1. HULC enhances CyclinD1 and thereby increases pRB and inhibited P21 WAF1/CIP 1 via autophagy-miR675-PKM2 pathway in human liver cancer stem cells. Ultimately, our results demonstrate that CyclinD1 is required for the oncogenic functions of HULC in liver cancer stem cells.

CONCLUSIONS

It reveals the key molecular signaling pathways for HULC and provides important basic information for finding effective tumor therapeutic targets based on HULC.

Metabolic Remodeling as a Way of Adapting to Tumor Microenvironment (TME), a Job of Several Holders

The microenvironment depends and generates dependence on all the cells and structures that share the same niche, the biotope. The contemporaneous view of the tumor microenvironment (TME) agrees with this idea. The cells that make up the tumor, whether malignant or not, behave similarly to classes of elements within a living community. These elements inhabit, modify and benefit from all the facilities the microenvironment has to offer and that will contribute to the survival and growth of the tumor and the progression of the disease.The metabolic adaptation to microenvironment is a crucial process conducting to an established tumor able to grow locally, invade and metastasized. The metastatic cancer cells are reasonable more plastic than non-metastatic cancer cells, because the previous ones must survive in the microenvironment where the primary tumor develops and in addition, they must prosper in the microenvironment in the metastasized organ.The metabolic remodeling requires not only the adjustment of metabolic pathways per se but also the readjustment of signaling pathways that will receive and obey to the extracellular instructions, commanding the metabolic adaptation. Many diverse players are pivotal in cancer metabolic fitness from the initial signaling stimuli, going through the activation or repression of genes, until the phenotype display. The new phenotype will permit the import and consumption of organic compounds, useful for energy and biomass production, and the export of metabolic products that are useless or must be secreted for a further recycling or controlled uptake. In the metabolic network, three subsets of players are pivotal: (1) the organic compounds; (2) the transmembrane transporters, and (3) the enzymes.This chapter will present the "Pharaonic" intent of diagraming the interplay between these three elements in an attempt of simplifying and, at the same time, of showing the complex sight of cancer metabolism, addressing the orchestrating role of microenvironment and highlighting the influence of non-cancerous cells.

MiR-29a function as tumor suppressor in cervical cancer by targeting SIRT1 and predict patient prognosis

INTRODUCTION

Cervical cancer is the second most frequently malignant tumors in females and metastasis is a challenge of the treatment of cervical cancer. MiR-29a is usually low expressed in several tumors and its functions in cervical cancer remain unclear.

PATIENTS AND METHODS

The quantitative real-time polymerase chain reaction was employed to assess the expression of miR-29a and the Sirtuin-1 (SIRT1). Cell metastatic ability was assessed using Transwell and Western blot assays. The dual-luciferase reporter assay was performed to verify that miR-29a targeted to the 3'-untranslated region (UTR) of SIRT1 mRNA.

RESULTS

MiR-29a was low expressed in cervical cancer and downregulation of miR-29a was associated with poor outcome. MiR-29a regulated the expression of SIRT1 by targeting to its 3'-UTR of mRNA in HeLa cells. SIRT1 was upregulated in cervical cancer tissues and cells in comparison with the non-tumor tissues and normal cells. Upregulation of SIRT1 predicted worse outcome of cervical cancer patients. MiR-29a was participated in the migration, invasion and epithelial-mesenchymal transition (EMT) in cervical cancer through directly targeting to the 3'-UTR of SIRT1 mRNA. SIRT1 reversed partial roles of miR-29a on metastasis in cervical cancer.

CONCLUSION

miR-29a suppressed migration, invasion and EMT by directly targeting to SIRT1 in cervical cancer. The newly identified miR-29a/SIRT1 axis provides novel insight into the pathogenesis of cervical cancer.