KLF13 suppresses the proliferation and growth of colorectal cancer cells through transcriptionally inhibiting HMGCS1-mediated cholesterol biosynthesis

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

miR-135b Aggravates Fusobacterium nucleatum-Induced Cisplatin Resistance in Colorectal Cancer by Targeting KLF13

Cisplatin resistance is the main cause of colorectal cancer (CRC) treatment failure, and the cause has been reported to be related to Fusobacterium nucleatum (Fn) infection. In this study, we explored the role of Fn in regulating cisplatin resistance of CRC cells and its underlying mechanism involved. The mRNA and protein expressions were examined by qRT-PCR and western blot. Cell proliferation and cell apoptosis were assessed using CCK8 and flow cytometry assays, respectively. Dual-luciferase reporter gene assay was adopted to analyze the molecular interactions. Herein, our results revealed that Fn abundance and miR-135b expression were markedly elevated in CRC tissues, with a favorable association between the two. Moreover, Fn infection could increase miR-135b expression via a concentration-dependent manner, and it also enhanced cell proliferation but reduced apoptosis and cisplatin sensitivity by upregulating miR-135b. Moreover, KLF13 was proved as a downstream target of miR-135b, of which overexpression greatly diminished the promoting effect of miR-135b or Fn-mediated cisplatin resistance in CRC cells. In addition, it was observed that upstream 2.5 kb fragment of miR-135b promoter could be interacted by β-catenin/TCF4 complex, which was proved as an effector signaling of Fn. LF3, a blocker of β-catenin/TCF4 complex, was confirmed to diminish the promoting role of Fn on miR-135b expression. Thus, it could be concluded that Fn activated miR-135b expression through TCF4/β-catenin complex, thereby inhibiting KLF13 expression and promoting cisplatin resistance in CRC.

A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses

Fractures caused by bone overloading are a leading cause of euthanasia in Thoroughbred racehorses. The risk of fatal fracture has been shown to be influenced by both environmental and genetic factors but, to date, no specific genetic mechanisms underpinning fractures have been identified. In this study, we utilised a genome-wide polygenic risk score to establish an in vitro cell system to study bone gene regulation in horses at high and low genetic risk of fracture. Candidate gene expression analysis revealed differential expression of COL3A1 and STAT1 genes in osteoblasts derived from high- and low-risk horses. Whole-genome sequencing of two fracture cases and two control horses revealed a single-nucleotide polymorphism (SNP) upstream of COL3A1 that was confirmed in a larger cohort to be significantly associated with fractures. Bioinformatics tools predicted that this SNP may impact the binding of the transcription factor SOX11. Gene modulation demonstrated SOX11 is upstream of COL3A1, and the region binds to nuclear proteins. Furthermore, luciferase assays demonstrated that the region containing the SNP has promoter activity. However, the specific effect of the SNP depends on the broader genetic background of the cells and suggests other factors may also be involved in regulating COL3A1 expression. In conclusion, we have identified a novel SNP that is significantly associated with fracture risk and provide new insights into the regulation of the COL3A1 gene.

Molecular Mechanisms of IL18 in Disease

Interleukin 18 (IL18) was originally identified as an inflammation-induced cytokine that is secreted by immune cells. An increasing number of studies have focused on its non-immunological functions, with demonstrated functions for IL18 in energy homeostasis and neural stability. IL18 is reportedly required for lipid metabolism in the liver and brown adipose tissue. Furthermore, IL18 (Il18) deficiency in mice leads to mitochondrial dysfunction in hippocampal cells, resulting in depressive-like symptoms and cognitive impairment. Microarray analyses of Il18-/- mice have revealed a set of genes with differential expression in liver, brown adipose tissue, and brain; however, the impact of IL18 deficiency in these tissues remains uncertain. In this review article, we discuss these genes, with a focus on their relationships with the phenotypic disease traits of Il18-/- mice.

Transcriptomic and metabolomic insights into the roles of exogenous β-hydroxybutyrate acid for the development of rumen epithelium in young goats

Beta-hydroxybutyric acid (BHBA), as one of the main metabolic ketones in the rumen epithelium, plays critical roles in cellular growth and metabolism. The ketogenic capacity is associated with the maturation of rumen in young ruminants, and the exogenous BHBA in diet may promote the rumen development. However, the effects of exogenous BHBA on rumen remain unknown. This is the first study to investigate the mechanisms of BHBA on gene expression and metabolism of rumen epithelium using young goats as a model through multi-omics techniques. Thirty-two young goats were divided into control, low dose, middle dose, and high dose groups by supplementation of BHBA in starter (0, 3, 6, and 9 g/day, respectively). Results demonstrated the dietary of BHBA promoted the growth performance of young goats and increased width and length of the rumen papilla (P < 0.05). Hub genes in host transcriptome that were positively related to rumen characteristics and BHBA concentration were identified. Several upregulated hub genes including NDUFC1, NDUFB4, NDUFB10, NDUFA11 and NDUFA1 were enriched in the gene ontology (GO) pathway of nicotinamide adenine dinucleotide (NADH) dehydrogenase (ubiquinone) activity, while ATP5ME, ATP5PO and ATP5PF were associated with ATP synthesis. RT-PCR revealed the expression of genes (HMGCS2, BDH1, SLC16A3, etc.) associated with lipolysis increased significantly by BHBA supplementation (P < 0.05). Metabolomics indicated that some metabolites such as glucose, palmitic acid, cortisol and capric acid were also increased (P < 0.05). This study revealed that BHBA promoted rumen development through altering NADH balance and accelerating lipid metabolism, which provides a theoretical guidance for the strategies of gastrointestinal health and development of young ruminants.

Krüppel-like Factor-9 and Krüppel-like Factor-13: Highly Related, Multi-Functional, Transcriptional Repressors and Activators of Oncogenesis

Specificity Proteins/Krüppel-like Factors (SP/KLF family) are a conserved family of transcriptional regulators. These proteins share three highly conserved, contiguous zinc fingers in their carboxy-terminus, requisite for binding to cis elements in DNA. Each SP/KLF protein has unique primary sequence within its amino-terminal and carboxy-terminal regions, and it is these regions which interact with co-activators, co-repressors, and chromatin-modifying proteins to support the transcriptional activation and repression of target genes. Krüppel-like Factor 9 (KLF9) and Krüppel-like Factor 13 (KLF13) are two of the smallest members of the SP/KLF family, are paralogous, emerged early in metazoan evolution, and are highly conserved. Paradoxically, while most similar in primary sequence, KLF9 and KLF13 display many distinct roles in target cells. In this article, we summarize the work that has identified the roles of KLF9 (and to a lesser degree KLF13) in tumor suppression or promotion via unique effects on differentiation, pro- and anti-inflammatory pathways, oxidative stress, and tumor immune cell infiltration. We also highlight the great diversity of miRNAs, lncRNAs, and circular RNAs which provide mechanisms for the ubiquitous tumor-specific suppression of KLF9 mRNA and protein. Elucidation of KLF9 and KLF13 in cancer biology is likely to provide new inroads to the understanding of oncogenesis and its prevention and treatments.

Kruppel-like factor 13 acts as a tumor suppressor in thyroid carcinoma by downregulating IFIT1

BACKGROUND

Kruppel-like factor 13 (KLF13) is a transcription factor and plays an important role in carcinogenesis. However, the significance of KLF13 in thyroid carcinoma (THCA) is underdetermined. In this study, we aimed to explore the clinical relevance and function of KLF13 in the progress of THCA.

METHODS

The expression of KLF13 in thyroid carcinoma and normal tissue was investigated by qPCR and IHC assay. The expression of KLF13 and IFIT1 in cell samples was investigated with Western blot assay. Cell proliferation ability was detected with CCK8 and colony formation assay. Cell growth in vivo with or without KLF13 overexpression was evaluated on a xenograft model. Cell migration ability was measured with Transwell assay. Cell cycle was detected with flow cytometer. The downstream genes of KLF13 were screened using RNA-seq assay. Luciferase activity was employed to assess the transcriptional regulation of KLF13 on IFIT1 promoter.

RESULTS

KLF13 expression was downregulated in THCA samples. KLF13 knockdown and overexpression promoted and inhibited the proliferation and migration of THCA cells, respectively. The RNA-seq, RT-qPCR and immunoblotting data showed that KLF13 knockdown significantly potentiated IFIT1 expression at both mRNA and protein levels. Luciferase assays showed that KLF13 suppressed the transcription activity of IFIT1 promoter. Besides, IFIT1 upregulation was critical for the proliferation and migration of THCA cell lines. Lastly, silencing of IFIT1 greatly reversed the proliferation and migration induced by KLF13 knockdown.

CONCLUSIONS

In conclusion, KLF13 may function as an anti-tumor protein in THCA by regulating the expression of IFIT1 and offer a theoretical foundation for treating thyroid carcinoma.

Paeoniflorin inhibits colorectal cancer cell stemness through the miR-3194-5p/catenin beta-interacting protein 1 axis

Paeoniflorin (PF) is a natural plant ingredient with remarkable antitumor effects. Herein, we investigated the biological effects and mechanism of PF in colorectal cancer (CRC) cell stemness. The messenger RNA (mRNA) and protein expressions were assessed using quantitative real-time polymerase chain reaction and western blot. The viability, proliferation, and migration and invasion of CRC cells were evaluated using cell counting kit-8, clone-formation, and transwell migration and invasion assays, respectively. The sphere-formation capacity was determined using the sphere-formation assay. A dual-luciferase reporter gene assay was employed to analyze the interaction between miR-3194-5p and catenin beta-interacting protein 1 (CTNNBIP1). The viability, migration, invasion, epithelial-mesenchymal transition, and stemness of CRC cells were repressed by PF. MiR-3194-5p was upregulated in CRC tissues and cells. MiR-3194-5p knockdown suppressed CRC cell stemness, while miR-3194-5p overexpression had the opposite effect. In addition, the inhibition of CRC cell stemness caused by PF was eliminated by miR-3194-5p overexpression. CTNNBIP1 functioned as the target of miR-3194-5p, whose knockdown abrogated the repression of CRC cell stemness and Wnt/β-catenin signaling activation by PF.PF regulated the miR-3194-5p/CTNNBIP1/Wnt/β-catenin axis to repress CRC cell stemness.

HUB genes transcriptionally regulate lipid metabolism in alveolar type II cells under LPS stimulation

Objective

Alveolar type II (ATII) cells produce pulmonary surfactant (PS) essential for maintaining lung function. The aberration or depletion of PS can cause alveolar collapse, a hallmark of acute respiratory distress syndrome (ARDS). However, the intricacies underlying these changes remain unclear. This study aimed to elucidate the mechanisms underlying PS perturbations in ATII cells using transcriptional RNA-seq, offering insights into the pathogenesis of ARDS.

Methods

ATII cells were identified using immunofluorescence targeting surface-active protein C. We used 24-h lipopolysaccharide (LPS)-induced ATII cells as an ARDS cell model. The efficacy of the injury model was gauged by detecting the presence of tumour necrosis factor-α and interleukin-6. RNA-seq analysis was performed to investigate the dynamics of PS deviation in unaltered and LPS-exposed ATII cells.

Results

Whole-transcriptome sequencing revealed that LPS-stimulated ATII cells showed significantly increased transcription of genes, including Lss, Nsdhl, Hmgcs1, Mvd, Cyp51, Idi1, Acss2, Insig1, and Hsd17b7, which play key roles in regulating cholesterol biosynthesis. We further verified gene levels using real-time quantitative PCR, and the results showed that the mRNA expression of these genes increased, which was consistent with the RNA-seq results.

Conclusion

Our study revealed pivotal transcriptional shifts in ATII cells after LPS exposure, particularly in nine key lipid and cholesterol metabolism genes. This altered expression might disrupt the lipid balance, ultimately affecting PS function. This finding deepens our understanding of the aetiology of ARDS and may lead to new therapeutic directions.

P4HA1 activates HMGCS1 to promote nasopharyngeal carcinoma ferroptosis resistance and progression

Ferroptosis is a novel type of iron-dependent regulatory cell death. To date, the regulatory mechanism of ferroptosis in nasopharyngeal carcinoma (NPC) remains poorly understood. In this study, we found that the prolyl 4-hydroxylase (P4H) subunit P4HA1 protects NPC cells from erastin-induced ferroptosis by activating HMGCS1, a key enzyme in the mevalonate pathway. We also found that the P4HA1/HMGCS1 axis promoted NPC cell proliferation in vitro. In vivo, downregulation of the P4HA1/HMGCS1 axis inhibited the growth of NPC cell xenografts and enhanced the inhibitory effect of erastin on tumor growth. Extracellular matrix (ECM) detachment is an important trigger for ferroptosis. We found that the P4HA1/HMGCS1 axis promoted the ferroptosis resistance and survival of ECM-detached NPC cells. In vivo, downregulation of the P4HA1/HMGCS1 axis inhibited the lung colonization of NPC cells and enhanced the inhibitory effect of erastin on NPC lung metastasis. Moreover, the high expression of P4HA1 predicted a poor prognosis and served as a potential independent prognostic factor in patients with NPC. In conclusion, P4HA1 is a novel molecular marker of NPC ferroptosis resistance and a poor prognosis, and the P4HA1/HMGCS1 axis provides a new target for the treatment of NPC progression.

Genome-Wide Analysis of the KLF Gene Family in Chicken: Characterization and Expression Profile

The kruppel-like factor (KLF) gene family is a group of transcription factors containing highly conserved zinc-finger motifs, which play a crucial role in cell proliferation and differentiation. Chicken has been widely used as a model animal for analyzing gene function, however, little is known about the function of the KLF gene family in chickens. In this study, we performed genome-wide studies of chicken KLF genes and analyzed their biological and expression characteristics. We identified 13 KLF genes from chickens. Our phylogenetic, motif, and conserved domain analyses indicate that the KLF gene family has remained conserved through evolution. Synteny analysis showed the collinear relationship among KLFs, which indicated that they had related biomolecular functions. Interaction network analysis revealed that KLFs worked with 20 genes in biological processes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that KLF2 was involved in Apelin and Forkhead Box O (FOXO) signaling pathways. Moreover, qPCR showed that 13 KLF genes were expressed in the nine selected tissues and displayed various gene expression patterns in chickens. RNA-seq showed that KLF3 and KLF10 genes were differentially expressed in the normal and high-fat diet fed groups, and KLF4, KLF5, KLF6, KLF7, KLF9, KLF12, and KLF13 genes were differentially expressed between undifferentiated and differentiated chicken preadipocytes. Besides, RNA-seq also showed that KLF genes displayed different expression patterns in muscle at 11 and 16 embryonic days old, and in 1-day-old chickens. These results indicated that the KLF genes were involved in the development of muscle and fat in chickens. Our findings provide some valuable reference points for the subsequent study of the function of KLF genes.

High expression of AP2M1 correlates with worse prognosis by regulating immune microenvironment and drug resistance to R-CHOP in diffuse large B cell lymphoma

BACKGROUND

First-line treatment with R-CHOP has cured 50%-60% patients of diffuse large B cell lymphoma (DLBCL), and more than one-third patients will eventually progressed to relapsed/refractory disease with dismal outcomes. Adaptor Related Protein Complex 2 Subunit Mu 1 (AP2M1) is required for the activity of a vacuolar ATPase and may also play an important role in regulating the intracellular trafficking and function of CTLA-4 protein. Herein, using both public databases and our own tumor samples, we aimed to demonstrate the prognostic role of AP2M1 and the potential tumor-promoting mechanisms in DLBCL.

METHOD

Using public datasets of DLBCL from both GEO and TCGA databases, we analyzed the role of AP2M1 in mediating chemoresistance to R-CHOP and its correlation with various clinical parameters and prognosis. By using various R packages, we evaluated the role of AP2M1 on regulating tumor immune microenvironment. Moreover, tumor samples of DLBCL from Beijing TongRen Hospital were used to validate our findings by immunohistochemistry staining.

RESULT

Expression of AP2M1 was significantly increased in DLBCL, which was correlated with poor prognosis and a variety of clinical indicators. On the basis of enrichment analysis, it was found that AP2M1 may be related to intracellular receptor signaling pathway. Through immune analysis and drug prediction, we found that the expression of AP2M1 affected the immune environment and drug response of DLBCL, which further revealed the important role of AP2M1 in DLBCL. By analyzing 61 patients treated uniformly with R-CHOP regimen in our center, we validated the above findings that high expression of AP2M1 correlated with inferior survival outcomes and affected sensitivity to R-CHOP treatment.

CONCLUSION

Expression of AP2M1 may affect the prognosis of DLBCL patients probably by affecting the immune environment and the responses to many drugs in treating DLBCL, indicating AP2M1 as a potential therapy target in DLBCL.

VIM‑AS1 promotes proliferation and drives enzalutamide resistance in prostate cancer via IGF2BP2‑mediated HMGCS1 mRNA stabilization

VIM‑AS1, a cancer‑specific long non‑coding RNA, has been recognized as a pivotal regulator in multiple types of cancer. However, the role of VIM‑AS1 in the proliferation and resistance to anti‑androgen therapy of LNCaP and C4‑2 prostate cancer cells remains to be determined. In the current study, gain‑and‑loss experiments were used to investigate the effects of VIM‑AS on the proliferation and anti‑androgen therapy of LNCaP and C4‑2 cells. RNA sequencing, RNA pulldown and RNA immunoprecipitation were used to elucidate the underlying mechanism of VIM‑AS1 driving prostate progression. It was demonstrated that VIM‑AS1 was upregulated in C4‑2 cells, an established castration‑resistant prostate cancer (CRPC) cell line, compared with in LNCaP cells, an established hormone‑sensitive prostate cancer cell line. The present study further demonstrated that VIM‑AS1 was positively associated with the clinical stage of prostate cancer. Functionally, overexpression of VIM‑AS1 decreased the sensitivity to enzalutamide treatment and enhanced the proliferation of LNCaP cells in vitro, whereas knockdown of VIM‑AS1 increased the sensitivity to enzalutamide treatment and reduced the proliferation of C4‑2 cells in vitro and in vivo. Mechanistically, 3‑hydroxy‑3‑methylglutaryl‑CoA synthase 1 (HMGCS1) was identified as one of the direct downstream targets of VIM‑AS1, and VIM‑AS1 promoted HMGCS1 expression by enhancing HMGCS1 mRNA stability through a VIM‑AS1/insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2)/HMGCS1 RNA‑protein complex. Rescue assays indicated that knockdown of HMGCS1 expression ameliorated the increase in proliferation and enzalutamide resistance of prostate cancer cells induced by VIM‑AS1 overexpression. Overall, the present study determined the roles and mechanism of the VIM‑AS1/IGF2BP2/HMGCS1 axis in regulating proliferation and enzalutamide sensitivity of prostate cancer cells and suggested that VIM‑AS1 may serve as a novel therapeutic target for the treatment of patients with CRPC.

KLF16 promotes pancreatic adenocarcinoma cell proliferation and migration by positively regulating SMAD6

BACKGROUND

Pancreatic adenocarcinoma (PAAD) is a cancerous tumor with an extremely poor 5-year survival rate. The exploration of biomarkers for the diagnosis and treatment of PAAD is crucial in clinical practice. Krüppel-like factors (KLFs) are involved in a variety of biological functions in cells. According to multiple studies, KLF16 behave as an oncogene in prostate, breast and gastric cancers. However, no research has been done on the significance of KLF16 in PAAD.

AIM

To explore the molecular mechanisms of KLF16 in PAAD.

METHODS

KLF16 was identified in the tumor specimens and normal tissues by GEPIA database and verified by quantitative real-time PCR (qRT-PCR). Knockdown or exogenous expression of KLF16, combined with in vitro and in vivo assays, was performed to show the functional significance of KLF16. The molecular mechanism of KLF16 was demonstrated by qRT-PCR, western blotting, immunoprecipitation assay and flow cytometry.

RESULTS

We showed that KLF16 was highly expressed in PAAD patients based on the GEPIA database. KLF16 silencing suppressed while KLF16 overexpression promoted the malignant function of PAAD cells. Based on RNA sequencing, we discovered that KLF16 potentiated the expression of SMAD6 in PAAD cells. SMAD6 transcript abundance was increased and positively correlated with KLF16 expression in PAAD samples. In addition, inhibiting SMAD6 was able to mitigate the effects of KLF16 overexpression on PAAD cell processes, suggesting the importance of SMAD6 in the development of KLF16-triggered PAAD.

CONCLUSION

KLF16/SMAD6 axis might be explored as a therapeutic target for PAAD therapy.

Comprehensive analyses of one-carbon metabolism related genes and their association with prognosis, tumor microenvironment, chemotherapy resistance and immunotherapy in lung adenocarcinoma

Background: Lung adenocarcinoma (LUAD) is the most common type of lung cancer and is a global public health concern. One-carbon (1C) metabolism plays a crucial role in the occurrence and development of multiple cancer types. However, there are limited studies investigating 1C metabolism in LUAD. This study aims to evaluate the prognostic value of 1C metabolism-related genes in LUAD and to explore the potential correlation of these genes with gene methylation, the tumor microenvironment, and immunotherapy. Methods: We identified 26 1C metabolism-related genes and performed a Kaplan-Meier and Cox regression analysis to evaluate the prognostic value of these genes. Consensus clustering was further performed to determine the 1C metabolism-related gene patterns in LUAD. The clinical and molecular characteristics of subgroups were investigated based on consensus clustering. CIBERSORT and ssGSEA algorithms were used to calculate the relative infiltration levels of multiple immune cell subsets. The relationship between 1C metabolism-related genes and drug sensitivity to immunotherapy was evaluated using the CellMiner database and IMvigor210 cohort, respectively. Results: The expression levels of 23 1C metabolism-related genes were significantly different between LUAD tumor tissues and normal tissues. Seventeen of these genes were related to prognosis. Two clusters (cluster 1 and cluster 2) were identified among 497 LUAD samples based on the expression of 7 prognosis-related genes. Distinct expression patterns were observed between the two clusters. Compared to cluster 2, cluster 1 was characterized by inferior overall survival (OS) (median OS = 41 vs. 60 months, p = 0.00031), increased tumor mutation burden (15.8 vs. 7.5 mut/Mb, p < 0.001), high expression of PD-1 (p < 0.001) and PD-L1 (p < 0.001), as well as enhanced immune infiltration. 1C metabolism-related genes were positively correlated with the expression of methylation enzymes, and a lower methylation level was observed in cluster 1 (p = 0.0062). Patients in cluster 1 were resistant to chemotherapy drugs including pemetrexed, gemcitabine, paclitaxel, etoposide, oxaliplatin, and carboplatin. The specific expression pattern of 1C metabolism-related genes was correlated with a better OS in patients treated with immunotherapy (median OS: 11.2 vs. 7.8 months, p = 0.0034). Conclusion: This study highlights that 1C metabolism is correlated with the prognosis of LUAD patients and immunotherapy efficacy. Our findings provide novel insights into the role of 1C metabolism in the occurrence, development, and treatment of LUAD, and can assist in guiding immunotherapy for LUAD patients.

Kruppel-like factor 13 inhibits cell proliferation of gastric cancer by inducing autophagic degradation of β-catenin

Zinc protein KLF13 is a tumor-suppressive member of Kruppel-like factors family, and yet the effect of KLF13 on gastric cancer has not been reported. Here, we aimed to investigate the role of KLF13 in gastric cancer and explored underlying molecular mechanisms. Firstly, it was found that KLF13 expression was significantly decreased in gastric cancer tissues and cancer cells compared with adjacent normal tissues and normal gastric epithelial cells, respectively. KEGG_Pathway and GO_BP analyses suggested that KLF13 was associated with CELL_CYCLE and CELL_PROLIFERATION. Then, our results further demonstrated that KLF13 could obviously inhibit gastric cancer proliferation and induce cell arrest at G2/M phase. Mechanistically, KLF13 decreased expressions of β-catenin and its target genes, CCND1 and MYC, via triggering autophagic degradation of β-catenin. KLF13 up-regulation facilitated co-localization and binding of β-catenin with autophagy protein p62, and exogenous overexpression of β-catenin or blocking autophagy process appeared to reverse KLF13-induced inhibition of gastric cancer proliferation. Furthermore, KLF13 overexpression promoted the expression of ubiquitin-conjugating enzyme E2, Ubc13 which is responsible for catalyzing the synthesis of 'Lys-63'-linked polyubiquitin chains and increased the binding of β-catenin with E3 ubiquitin ligase, TRAF6. In vivo, KLF13 overexpression also suppressed xenograft tumor growth of gastric cancer and down-regulated expressions of Ki67, β-catenin, Cyclin D1, and c-Myc in tumor tissues. Collectively, these data firstly demonstrated the involvement of KLF13 in inhibiting cell proliferation of gastric cancer through promoting autophagy-dependent degradation of β-catenin, which reinforced the evidence for suppressive roles of KLF13 in human tumors.

SP and KLF Transcription Factors in Cancer Metabolism

Tumor development and progression depend on reprogramming of signaling pathways that regulate cell metabolism. Alterations to various metabolic pathways such as glycolysis, oxidative phosphorylation, lipid metabolism, and hexosamine biosynthesis pathway are crucial to sustain increased redox, bioenergetic, and biosynthesis demands of a tumor cell. Transcription factors (oncogenes and tumor suppressors) play crucial roles in modulating these alterations, and their functions are tethered to major metabolic pathways under homeostatic conditions and disease initiation and advancement. Specificity proteins (SPs) and Krüppel-like factors (KLFs) are closely related transcription factors characterized by three highly conserved zinc fingers domains that interact with DNA. Studies have demonstrated that SP and KLF transcription factors are expressed in various tissues and regulate diverse processes such as proliferation, differentiation, apoptosis, inflammation, and tumorigenesis. This review highlights the role of SP and KLF transcription factors in the metabolism of various cancers and their impact on tumorigenesis. A better understanding of the role and underlying mechanisms governing the metabolic changes during tumorigenesis could provide new therapeutic opportunities for cancer treatment.

MicroRNA-379-5p regulates free cholesterol accumulation and relieves diet induced-liver damage in db/db mice via STAT1/HMGCS1 axis

Lipotoxicity induced by the overload of lipid in the liver, especially excess free cholesterol (FC), has been recognized as one of driving factors in the transition from non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH). MicroRNA (miR)-379-5p has been reported to play regulatory roles in hepatic triglyceride homeostasis, but the relationship of miR-379-5p and hepatic cholesterol homeostasis has never been touched. In the current study, we found that hepatic miR-379-5p levels were decreased obviously in NAFLD patients and model mice compared with their controls. Moreover, miR-379-5p was discovered to be able to inhibit intracellular FC accumulation and alleviate mitochondrial damage induced by palmitic acid (PA) in vitro. Furthermore, overexpression of miR-379-5p in HFHC-fed db/db mice could reduce the level of hepatic total cholesterol (TC) and FC, and ameliorate hepatic injury reflected by the lower serum alanine aminotransferase (ALT) and aspartate transaminase (AST). Subsequently, by combining spectrometry (MS) and luciferase assay, we identified miR-379-5p suppressed STAT1 through transcriptional and translational regulation. Finally, we confirmed that STAT1 was a transcriptional factor of HMGCS1. In conclusion, miR-379-5p inhibits STAT1 expression and regulates cholesterol metabolism through the STAT1/HMGCS1 axis, suggesting miR-379-5p might be applied to improve lipotoxicity in the future.

Ursolic acid inhibits the cholesterol biosynthesis and alleviates high fat diet-induced hypercholesterolemia via irreversible inhibition of HMGCS1 in vivo

BACKGROUND

In hypercholesteremia, the concentrations of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are enhanced in serum, which is strongly associated with an increased risk of developing atherosclerosis. Ursolic acid (UA), a pentacyclic terpenoid carboxylic acid, was found to alleviate hypercholesterolemia and hypercholesterolemia-induced cardiovascular disease. However, the specific targets and molecular mechanisms related to the effects of UA in reducing cholesterol have not been elucidated.

PURPOSE

In this study, we aimed to illustrate the target of UA in the treatment of hypercholesterolemia and to reveal its underlying molecular mechanism.

METHODS

Nontargeted metabolomics was conducted to analyze the metabolites and related pathways that UA affected in vivo. The main lipid metabolism targets of UA were analyzed by target fishing and fluorescence colocalization in mouse liver. Molecular docking, in-gel fluorescence scan and thermal shift were assessed to further investigate the binding site of the UA metabolite with HMGCS1. C57BL/6 mice were fed a high-fat diet (HFD) for 12 weeks to induce hypercholesteremia. Liver tissues were used to verify the cholesterol-lowering molecular mechanism of UA by targeted metabolomics, serum was used to detect biochemical indices, and the entire aorta was used to analyze the formation of atherosclerotic lesions.

RESULTS

Our results showed that hydroxy‑3-methylglutaryl coenzyme A synthetase 1 (HMGCS1) was the primary lipid metabolism target protein of UA. The UA metabolite epoxy-modified UA irreversibly bonds with the thiol of Cys-129 in HMGCS1, which inhibits the catalytic activity of HMGCS1 and reduces the generation of precursors in cholesterol biosynthesis in vivo. The contents of TC and LDL-C in serum and the formation of the atherosclerotic area in the entire aorta were markedly reduced with UA treatment in Diet-induced hypercholesteremia mice.

CONCLUSION

UA inhibits the catalytic activity of HMGCS1, reduces the generation of downstream metabolites in the process of cholesterol biosynthesis and alleviates Diet-induced hypercholesteremia via irreversible binding with HMGCS1 in vivo. It is the first time to clarify the irreversible inhibition mechanism of UA against HMGCS1. This paper provides an increased understanding of UA, particularly regarding the molecular mechanism of the cholesterol-lowering effect, and demonstrates the potential of UA as a novel therapeutic for the treatment of hypercholesteremia.

Determination of the Effects of Duodenal Infusion Soy Protein Hydrolysate on Hepatic Glucose and Lipid Metabolism in Pigs Through Multi-Omics Analysis

High animal protein intake increases hepatic lipid deposition and the risk of diabetes. However, the effects of high plant protein (HPP) intake on glycaemic responses and hepatic lipid metabolism in healthy people, as well as the underlying mechanisms, remain unclear. The current study explored the metabolomic and transcriptomic responses in the livers of pigs to assess the effects of HPP intake on host glucose and lipid metabolism. Sixteen pigs were infused with sterile saline or soy protein hydrolysate (SPH; 70 g/day) through a duodenal fistula twice daily during a 15 days experimental period. Hepatic metabolomic and transcriptomic analyses were performed, and the serum and hepatic biochemical parameters were measured. The results revealed that SPH infusion decreased serum glucose, hepatic triglyceride (TG), total cholesterol and low-density lipoprotein cholesterol levels, while it increased serum urea and eight hepatic amino acid levels (P < 0.05). Hepatic metabolomics displayed that SPH treatment produced seven different metabolites, four of which were related to lipid metabolism and one was related to glucose metabolism. In particular, lower (P < 0.05) glycocholic acid and glucose 1-phosphate levels and higher (P < 0.05) phosphatidylethanolamine (PE), arachidonic acid, prostaglandin F2α, l-carnitine and indole-3 acetic acid levels were observed following SPH infusion. A further metabolic pathway enrichment analysis found that these differential metabolites were mainly enriched in pathways related to lipid and glucose metabolism. Hepatic transcriptomics also demonstrated that multiple genes related to glucose and lipid metabolism were affected by SPH (P < 0.05). Together, SPH infusion reduced the hepatic TG levels by accelerating fatty acid β-oxidation and inhibiting TG synthesis. In addition, SPH infusion reduced the serum glucose levels by promoting hepatic glucose uptake and glycolysis. This study's result demonstrated that HPP intake regulated glycaemic responses and hepatic lipid metabolism in pigs without increasing the risk of hepatic lipid deposition and hyperglycaemia.

Kruppel like factor 16 promotes lung adenocarcinoma progression by upregulating lamin B2

Lung cancer is one of the most common causes of cancer-related death. In the past decade, the treatment and diagnosis of lung cancer have progressed significantly in early efforts to promote the survival of lung cancer patients. Kruppel like factor 16 (KLF16) is a zinc finger transcription factor that regulates a diverse array of developmental events and cellular processes. KLF16 is involved in the progression of various cancer types. However, the role of KLF16 in the development of lung cancer remains unknown. In this study, KLF16 was overexpressed in lung cancer samples. KLF16 downregulation inhibited lung cancer cell proliferation and migration. Conversely, KLF16 overexpression promoted lung cancer cell growth and invasion. Mechanistically, the expression level LMNB2 was suppressed by KLF16 knockdown and was promoted by KLF16 overexpression. The overall survival of patients with high LMNB2 levels was poor. Luciferase assays showed that KLF16 promoted the transcription activity of LMNB2 gene. Concomitantly, the expression level of LMNB2 was also higher in lung adenocarcinoma (LUAD) than in normal tissues, and its knockdown or overexpression can reverse the effect of KLF16 overexpression or knockdown on lung cancer cell proliferation, migration, and even tumorigenesis, indicating that LMNB2 also functions as an oncogene. In conclusion, KLF16 can be used as a potential therapeutic and preventive biomarker in lung cancer treatment and prognosis by actively regulating the expression of LMNB2.

Novel Insights into the Differences in Nutrition Value, Gene Regulation and Network Organization between Muscles from Pasture-Fed and Barn-Fed Goats

The physiological and biochemical characters of muscles derived from pasture-fed or barn-fed black goats were detected, and RNA-seq was performed to reveal the underlying molecular mechanisms to identify how the pasture feeding affected the nutrition and flavor of the meat. We found that the branched chain amino acids, unsaturated fatty acids, and zinc in the muscle of pasture-fed goats were significantly higher than those in the barn-fed group, while the heavy metal elements, cholesterol, and low-density lipoprotein cholesterol were significantly lower. RNA-seq results showed that 1761 genes and 147 lncRNA transcripts were significantly differentially expressed between the pasture-fed and barn-fed group. Further analysis found that the differentially expressed genes were mainly enriched in the myogenesis and Glycerophospholipid metabolism pathway. A functional analysis of the lncRNA transcripts further highlighted the difference in fatty acid metabolism between the two feeding models. Our study provides novel insights into the gene regulation and network organization of muscles and could be potentially used for improving the quality of mutton.

Acyl-CoA Thioesterase 7 is Transcriptionally Activated by Krüppel-Like Factor 13 and Promotes the Progression of Hepatocellular Carcinoma

Purpose

Acyl-CoA thioesterase 7(ACOT7) plays an important role in the metabolism of fatty acids. Hepatocellular carcinoma (HCC) has an abnormal lipid profile, and the role of ACOT7 in hepatocellular carcinoma has not been detailedly elucidated. Therefore, we conducted the study to explore the role of ACOT7 in HCC.

Materials and Methods

The ACOT7 and Krüppel-like factor 13 (KLF13) mRNA expression levels were obtained from The Cancer Genome Atlas (TCGA) database. Bioinformatics analysis identified the underlying upstream regulator of ACOT7. Quantitative real-time PCR was used to detect the expression of mRNA, and immunohistochemical staining and Western blotting were used to detect the expression of protein. Cell Counting Kit-8 and EdU assays were employed to assess the proliferation of HCC cells. Wound-healing and Transwell migration assays were utilized to test the migration ability of HCC cells. Dual-luciferase reporter assay and ChIP assay were used to explore the potential mechanism. Gas chromatography-mass spectrometer was used to analyze the content of free fatty acids. Xenograft tumour growth was used to evaluate the effect of ACOT7 in vivo.

Results

According to The Cancer Genome Atlas (TCGA) database, ACOT7 mRNA was found to be upregulated and predicted the poor prognosis. Overexpression of ACOT7 enhanced the proliferation, migration and invasion abilities of HCC cells in vitro, as well as the HCC cells proliferation in vivo. Moreover, ACOT7 overexpression increased the yield of the monounsaturated fatty acid Oleic acid (C18:1), which strengthened the proliferation and migration abilities of HCC cells. Mechanistically, KLF13 transcriptionally promoted ACOT7 expression. Further, KLF13 was also overexpressed in HCC tissues and facilitated HCC progression.

Conclusion

Acyl-CoA thioesterase 7 is transcriptionally activated by Krüppel-like factor 13 and promotes the progression of hepatocellular carcinoma.

Astrocytic YAP prevents the demyelination through promoting expression of cholesterol synthesis genes in experimental autoimmune encephalomyelitis

Cholesterols are the main components of myelin, and are mainly synthesized in astrocytes and transported to oligodendrocytes and neurons in the adult brain. It has been reported that Hippo/yes-associated protein (YAP) pathways are involved in cholesterol synthesis in the liver, however, it remains unknown whether YAP signaling can prevent the demyelination through promoting cholesterol synthesis in experimental autoimmune encephalomyelitis (EAE), a commonly used animal model of multiple sclerosis characterized by neuroinflammation and demyelination. Here, we found that YAP was upregulated and activated in astrocytes of spinal cords of EAE mice through suppression of the Hippo pathway. YAP deletion in astrocytes aggravated EAE with earlier onset, severer inflammatory infiltration, demyelination, and more loss of neurons. Furthermore, we found that the neuroinflammation was aggravated and the proliferation of astrocytes was decreased in YAPGFAP-CKO EAE mice. Mechanically, RNA-seq revealed that the expression of cholesterol-synthesis pathway genes such as HMGCS1 were decreased in YAP-/- astrocytes. qPCR, western blot, and immunostaining further confirmed the more significant reduction of HMGCS1 in spinal cord astrocytes of YAPGFAP-CKO EAE mice. Interestingly, upregulation of cholesterol-synthesis pathways by diarylpropionitrile (DPN) (an ERβ-ligand, to upregulate the expression of HMGCS1) treatment partially rescued the demyelination deficits in YAPGFAP-CKO EAE mice. Finally, activation of YAP by XMU-MP-1 treatment promoted the expression of HMGCS1 in astrocytes and partially rescued the demyelination and inflammatory infiltration deficits in EAE mice. These findings identify unrecognized functions of astrocytic YAP in the prevention of demyelination through promoting cholesterol synthesis in EAE, and reveal a novel pathway of YAP/HMGCS1 for cholesterol synthesis in EAE pathology.

MicroRNA related prognosis biomarkers from high throughput sequencing data of kidney renal clear cell carcinoma

BACKGROUND

Kidney renal clear cell carcinoma (KIRC) is the most common type of kidney cell carcinoma which has the worst overall survival rate. Almost 30% of patients with localized cancers eventually develop to metastases despite of early surgical treatment carried out. MicroRNAs (miRNAs) play a critical role in human cancer initiation, progression, and prognosis. The aim of our study was to identify potential prognosis biomarkers to predict overall survival of KIRC.

METHODS

All data were downloaded from an open access database The Cancer Genome Atlas. DESeq2 package in R was used to screening the differential expression miRNAs (DEMs) and genes (DEGs). RegParallel and Survival packages in R was used to analysis their relationships with the KIRC patients. David version 6.8 and STRING version 11 were used to take the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis.

RESULTS

We found 2 DEGs (TIMP3 and HMGCS1) and 3 DEMs (hsa-miR-21-5p, hsa-miR-223-3p, and hsa-miR-365a-3p) could be prognosis biomarkers for the prediction of KIRC patients. The constructed prognostic model based on those 2 DEGs could effectively predict the survival status of KIRC. And the constructed prognostic model based on those 3 DEMs could effectively predict the survival status of KIRC in 3-year and 5-year.

CONCLUSION

The current study provided novel insights into the miRNA related mRNA network in KIRC and those 2 DEGs biomarkers and 3 DEMs biomarkers may be independent prognostic signatures in predicting the survival of KIRC patients.

HMGCS1 drives drug-resistance in acute myeloid leukemia through endoplasmic reticulum-UPR-mitochondria axis

Hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) is a key enzyme in the mevalonate pathway of cholesterol synthesis. Dysregulation of HMGCS1 expression is a common occurrence in many solid tumors. It was also found to be overexpressed in newly diagnosed (ND) and relapsed/refractory (RR) acute myeloid leukemia (AML) patients. Previous study proved that HMGCS1 could induce drug-resistance in AML cells. However, the underlying mechanism how HMGCS1 contributed to chemoresistance remains elusive. Here, we confirmed that HMGCS1 inhibitor Hymeglusin enhanced cytarabine/Adriamycin (Ara-c/ADR) chemo-sensitivity in AML cells lines. Moreover, Ara-c-resistant HL-60 cells (HL-60/Ara-c) and ADR-resistant HL-60 cells (HL-60/ADR) were more sensitive to HMGCS1 inhibition than HL-60 cells. In addition, we demonstrated that the transcription factor GATA1 was the upstream regulator of HMGCS1 and could directly bind to the HMGCS1 promoter. After treatment of Tunicamycin (Tm), the number of mitochondria was increased and the damage of endoplasmic reticulum (ER) was reduced in bone marrow cells from AML-RR patients, compared to cells from AML-CR group. HMGCS1 protected mitochondria and ER under ER stress and up-regulated unfold protein response (UPR) downstream molecules in AML cells. In summary, we proved that HMGCS1 could upregulate UPR downstream components, protect mitochondria and ER from damage in AML cells under stress, therefore conferring drug resistance. Therefore, HMGCS1 could serve as a novel target for treatment of patients with intolerant chemotherapy and AML-RR patients.

A new horizon for the old antibacterial drug clofoctol

The synthetic antibacterial drug clofoctol (CFT) has long been used to treat respiratory tract infections in Europe. In recent years, the drug was found to target two biologically important proteins, the Cdc7/Dbf4 protein kinase complex and the mRNA-binding protein cold shock domain containing E1 (CSDE1), also known as upstream-of-N-Ras protein (UNR). These interactions are at the origin of the antitumor activity of CFT, recently evidenced in prostate cancer and neuroglioma. Drug-protein binding models provide a structural basis to guide the design of more potent anticancer compounds. A renewed interest in CFT can be anticipated for the treatment of cancers, and possibly Coronavirus 2019 (COVID-19).