SREBP1, targeted by miR-18a-5p, modulates epithelial-mesenchymal transition in breast cancer via forming a co-repressor complex with Snail and HDAC1/2

miR-18a-5p promotes osteogenic differentiation of BMSC by inhibiting Notch2

Postmenopausal osteoporosis (PMOP) is a metabolic disorder characterized by the loss of bone density, which increases the risk of developing complications such as fractures. A pivotal factor contributing to the onset of PMOP is the diminished osteogenic differentiation capacity of bone marrow mesenchymal stem cells (BMSCs). MicroRNAs (miRNAs) play a substantial role in this process; however, their specific impact on regulating BMSCs osteogenesis remains unclear. Studies have evidenced a reduced expression of miR-18a-5p in PMOP, and concomitantly, our observations indicate an augmented expression of miR-18a-5p during the osteogenic differentiation of BMSCs. This investigation seeks to elucidate the regulatory influence of miR-18a-5p on BMSC osteogenic differentiation and the underlying mechanisms. In vitro experiments demonstrated that the overexpression of miR-18a-5p facilitated the osteogenic differentiation of BMSCs, while the downregulation of miR-18a-5p yielded converse outcomes. Mechanistically, We employed bioinformatics techniques to screen out the target gene Notch2 of miR-18a-5p. Subsequently, dual-luciferase reporter gene assays and rescue experiments substantiated that miR-18a-5p promotes BMSC osteogenic differentiation by suppressing Notch2. Finally, miR-18a-5p was overexpressed via adenovirus injection into the femoral bone marrow cavity, with results demonstrating its capability to enhance osteogenic differentiation and alleviate PMOP symptoms. Our findings disclose that miR-18a-5p fosters osteogenic differentiation of BMSC by inhibiting Notch2, thereby offering novel targets and strategies for PMOP treatment.

The roles and mechanisms of SREBP1 in cancer development and drug response

Cancer occurrence and development are closely related to increased lipid production and glucose consumption. Lipids are the basic component of the cell membrane and play a significant role in cancer cell processes such as cell-to-cell recognition, signal transduction, and energy supply, which are vital for cancer cell rapid proliferation, invasion, and metastasis. Sterol regulatory element-binding transcription factor 1 (SREBP1) is a key transcription factor regulating the expression of genes related to cholesterol biosynthesis, lipid homeostasis, and fatty acid synthesis. In addition, SREBP1 and its upstream or downstream target genes are implicated in various metabolic diseases, particularly cancer. However, no review of SREBP1 in cancer biology has yet been published. Herein, we summarized the roles and mechanisms of SREBP1 biological processes in cancer cells, including SREBP1 modification, lipid metabolism and reprogramming, glucose and mitochondrial metabolism, immunity, and tumor microenvironment, epithelial-mesenchymal transition, cell cycle, apoptosis, and ferroptosis. Additionally, we discussed the potential role of SREBP1 in cancer prognosis, drug response such as drug sensitivity to chemotherapy and radiotherapy, and the potential drugs targeting SREBP1 and its corresponding pathway, elucidating the potential clinical application based on SREBP1 and its corresponding signal pathway.

Inhibition of Nogo-B reduces the progression of pancreatic cancer by regulation NF-κB/GLUT1 and SREBP1 pathways

Pancreatic cancer (PC) is a lethal disease and associated with metabolism dysregulation. Nogo-B is related to multiple metabolic related diseases and types of cancers. However, the role of Nogo-B in PC remains unknown. In vitro, we showed that cell viability and migration was largely reduced in Nogo-B knockout or knockdown cells, while enhanced by Nogo-B overexpression. Consistently, orthotopic tumor and metastasis was reduced in global Nogo knockout mice. Furthermore, we indicated that glucose enhanced cell proliferation was associated to the elevation expression of Nogo-B and nuclear factor κB (NF-κB). While, NF-κB, glucose transporter type 1 (GLUT1) and sterol regulatory element-binding protein 1 (SREBP1) expression was reduced in Nogo-B deficiency cells. In addition, we showed that GLUT1 and SREBP1 was downstream target of NF-κB. Therefore, we demonstrated that Nogo deficiency inhibited PC progression is regulated by the NF-κB/GLUT1 and SREBP1 pathways, and suggested that Nogo-B may be a target for PC therapy.

Integrating single-cell and spatial analysis reveals MUC1-mediated cellular crosstalk in mucinous colorectal adenocarcinoma

BACKGROUND

Mucinous colorectal adenocarcinoma (MCA) is a distinct subtype of colorectal cancer (CRC) with the most aggressive pattern, but effective treatment of MCA remains a challenge due to its vague pathological characteristics. An in-depth understanding of transcriptional dynamics at the cellular level is critical for developing specialised MCA treatment strategies.

METHODS

We integrated single-cell RNA sequencing and spatial transcriptomics data to systematically profile the MCA tumor microenvironment (TME), particularly the interactome of stromal and immune cells. In addition, a three-dimensional bioprinting technique, canonical ex vivo co-culture system, and immunofluorescence staining were further applied to validate the cellular communication networks within the TME.

RESULTS

This study identified the crucial intercellular interactions that engaged in MCA pathogenesis. We found the increased infiltration of FGF7+/THBS1+ myofibroblasts in MCA tissues with decreased expression of genes associated with leukocyte-mediated immunity and T cell activation, suggesting a crucial role of these cells in regulating the immunosuppressive TME. In addition, MS4A4A+ macrophages that exhibit M2-phenotype were enriched in the tumoral niche and high expression of MS4A4A+ was associated with poor prognosis in the cohort data. The ligand-receptor-based intercellular communication analysis revealed the tight interaction of MUC1+ malignant cells and ZEB1+ endothelial cells, providing mechanistic information for MCA angiogenesis and molecular targets for subsequent translational applications.

CONCLUSIONS

Our study provides novel insights into communications among tumour cells with stromal and immune cells that are significantly enriched in the TME during MCA progression, presenting potential prognostic biomarkers and therapeutic strategies for MCA.

KEY POINTS

Tumour microenvironment profiling of MCA is developed. MUC1+ tumour cells interplay with FGF7+/THBS1+ myofibroblasts to promote MCA development. MS4A4A+ macrophages exhibit M2 phenotype in MCA. ZEB1+ endotheliocytes engage in EndMT process in MCA.

MIER2/PGC1A elicits sunitinib resistance via lipid metabolism in renal cell carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) is one of the most common malignant tumors of the urinary system and accounts for more than 90 % of all renal tumors. Resistance to targeted therapy has emerged as a pivotal factor that contributes to the progressive deterioration of patients with advanced RCC. Metabolic reprogramming is a hallmark of tumorigenesis and progression, with an increasing body of evidence indicating that abnormal lipid metabolism plays a crucial role in the advancement of renal clear cell carcinoma.

OBJECTIVES

Clarify the precise mechanisms underlying abnormal lipid metabolism and drug resistance.

METHODS

Bioinformatics screening and analyses were performed to identify hub gene. qRT-PCR, western blot, chromatin immunoprecipitation (ChIP) assays, and other biological methods were used to explore and verify related pathways. Various cell line models and animal models were used to perform biological functional experiments.

RESULTS

In this study, we identified Mesoderm induction early response 2 (MIER2) as a novel biomarker for RCC, demonstrating its role in promoting malignancy and sunitinib resistance by influencing lipid metabolism in RCC. Mechanistically, MIER2 facilitated P53 deacetylation by binding to HDAC1. Acetylation modification augmented the DNA-binding stability and transcriptional function of P53, while deacetylation of P53 hindered the transcriptional process of PGC1A, leading to intracellular lipid accumulation in RCC. Furthermore, Trichostatin A (TSA), an inhibitor of HDAC1, was found to impede the MIER2/HDAC1/P53/PGC1A pathway, offering potential benefits for patients with sunitinib-resistant renal cell cancer.

CONCLUSION

Our findings highlight MIER2 as a key player in anchoring HDAC1 and inhibiting PGC1A expression through the deacetylation of P53, thereby inducing lipid accumulation in RCC and promoting drug resistance. Lipid-rich RCC cells compensate for energy production and sustain their own growth in a glycolysis-independent manner, evading the cytotoxic effects of targeted drugs and ultimately culminating in the development of drug resistance.

Lipid droplets' functional protein caveolin-2 is associated with lipid metabolism-related molecule FABP5 and EMT marker E-cadherin in oral epithelial dysplasia

AIMS

To explore the accumulation of lipid droplets (LDs) and its relationship with lipid metabolism, and epithelial-mesenchymal transition (EMT) in the carcinogenesis processes in the oral cavity.

METHODS

LDs were stained by oil red O. Forty-eight oral squamous cell carcinomas (OSCC), 78 oral potentially malignant disorders (OPMDs) and 25 normal tissue sections were included to explore the LDs surface protein caveolin-2 and perilipin-3, lipid metabolism-related molecule FABP5 and EMT biomarker E-cadherin expression by immunohistochemical staining.

RESULTS

The accumulation of LDs was observed in OPMDs and OSCCs compared with normal tissues (p<0.05). In general, an increasing trend of caveolin-2, perilipin-3 and FABP5 expression was detected from the normal to OPMDs to OSCC groups (p<0.05). Additionally, caveolin-2, perilipin-3 and FABP5 expression were positively correlated with epithelial dysplasia in OPMDs, whereas E-cadherin positivity was negatively correlated with histopathological grade in both OPMDs and OSCC, respectively. A negative correlation of caveolin-2 (p<0.01, r =-0.1739), and FABP5 (p<0.01, r =-0.1880) with E-cadherin expression was detected. The caveolin-2 (p<0.0001, r=0.2641) and perilipin-3 (p<0.05, r=0.1408) staining was positively correlated with FABP5. Increased caveolin-2 expression was related to local recurrence and worse disease-free survival (p<0.05).

CONCLUSION

In the oral epithelial carcinogenesis process, LDs begin to accumulate early in the precancerous stage. LDs may be the regulator of FABP5-associated lipid metabolism and may closely related to the process of EMT; caveolin-2 could be the main functional protein.

LINC01686 affects LPS-induced cytokine expression via the miR-18a-5p/A20/STAT1 axis in THP-1 cells

BACKGROUND AND OBJECTIVE

Long noncoding RNAs (lncRNAs) are crucial in regulating various physiological and pathological processes, including immune responses. LINC01686 is a lncRNA with previously uncharacterized functions in immune regulation. This study aims to investigate the function of LINC01686 in lipopolysaccharide (LPS)-induced inflammatory responses in the human monocytic leukemia cell line THP-1 and its potential regulatory mechanisms involving miR-18a-5p and the anti-inflammatory protein A20.

METHOD

THP-1 cells were stimulated with LPS to induce inflammatory responses, followed by analysis of LINC01686 expression levels. The role of LINC01686 in regulating the expression of interleukin (IL)-6, IL-8, A20, and signal transducer and activator of transcription 1 (STAT1) was examined using small interfering RNA-mediated knockdown. Additionally, the involvement of miR-18a-5p in LINC01686-mediated regulatory pathways was assessed by transfection with decoy RNAs mimicking the miR-18a-5p binding sites of LINC01686 or A20 messenger RNA.

RESULTS

LINC01686 expression was upregulated in THP-1 cells following LPS stimulation. Suppression of LINC01686 enhanced LPS-induced expression of IL-6 and IL-8, mediated through increased production of reactive oxygen species. Moreover, LINC01686 knockdown upregulated the expression and activation of IκB-ζ, STAT1, and downregulated A20 expression. Transfection with decoy RNAs reversed the effects of LINC01686 suppression on A20, STAT1, IL-6, and IL-8 expression, highlighting the role of LINC01686 in sponging miR-18a-5p and regulating A20 expression.

CONCLUSION

This study provides the first evidence that LINC01686 plays a critical role in modulating LPS-induced inflammatory responses in THP-1 cells by sponging miR-18a-5p, thereby regulating the expression and activation of A20 and STAT1. These findings shed light on the complex regulatory mechanisms involving lncRNAs in immune responses and offer potential therapeutic targets for inflammatory diseases.

USP30 promotes the progression of breast cancer by stabilising Snail

Breast cancer (BC) is the most prevalent tumour in women worldwide. USP30 is a deubiquitinase that has been previously reported to promote tumour progression and lipid synthesis in hepatocellular carcinoma. However, the role of USP30 in breast cancer remains unclear. Therefore, we investigated its biological action and corresponding mechanisms in vitro and in vivo. In our study, we found that USP30 was highly expressed in breast cancer samples and correlated with a poor patient prognosis. Knockdown of USP30 significantly suppressed the proliferation, invasion and migration abilities of BC cells in vitro and tumour growth in vivo, whereas overexpression of USP30 exhibited the opposite effect. Mechanistically, we verified that USP30 interacts with and stabilises Snail to promote its protein expression through deubiquitination by K48-linked polyubiquitin chains and then accelerates the EMT program. More importantly, USP30 reduced the chemosensitivity of BC cells to paclitaxel (PTX). Collectively, these data demonstrate that USP30 promotes the BC cell EMT program by stabilising Snail and attenuating chemosensitivity to PTX and may be a potential therapeutic target in BC.

The lipid metabolism remodeling: A hurdle in breast cancer therapy

Lipids, as one of the three primary energy sources, provide energy for all cellular life activities. Lipids are also known to be involved in the formation of cell membranes and play an important role as signaling molecules in the intracellular and microenvironment. Tumor cells actively or passively remodel lipid metabolism, using the function of lipids in various important cellular life activities to evade therapeutic attack. Breast cancer has become the leading cause of cancer-related deaths in women, which is partly due to therapeutic resistance. It is necessary to fully elucidate the formation and mechanisms of chemoresistance to improve breast cancer patient survival rates. Altered lipid metabolism has been observed in breast cancer with therapeutic resistance, indicating that targeting lipid reprogramming is a promising anticancer strategy.

CAFs-derived exosomes promote the development of cervical cancer by regulating miR-18a-5p-TMEM170B signaling axis

Mounting studies have showed that tumor microenvironment (TME) is crucial for cervical cancer (CC), and cancer-related fibroblasts (CAFs) play a major role in it. Recently, exosomal miRNAs secreted by CAFs have been found to be potential targets for cancer diagnosis and therapy. In this paper, we aimed to investigate the function of CAFs-mediated exosome miR-18a-5p (CAFs-exo-miR-18a-5p) in CC. First, in combination with bioinformatic data analysis of the GEO database (GSE86100) and RT-qPCR of CC clinical tissue samples and cell lines, miR-18a-5p was discovered to be markedly up-regulated in CC. Next, CAFs-secreted exosomes were isolated and it was found that miR-18a-5p expression was dramatically promoted in CC cell lines when treated with CAFs-exos. The CAFs-exo-miR-18a-5p was then elucidated to stimulate the proliferation and migration and inhibit the apoptosis of CC cells. In order to clarify the underlying mechanism, we further screened the target genes of miR-18a-5p. TMEM170B was selected by bioinformatic data analysis of online databases combined with RT-qPCR of CC clinical tissues and cells. Luciferase reporter gene analysis combined with molecular biology experiments further elucidated that miR-18a-5p suppressed TMEM170B expression in CC. Finally, both cell and animal experiments demonstrated that TMEM170B over-expression attenuated the oncogenic effect of CAFs-exo-miR-18a-5p. In conclusion, our study indicates that CAFs-mediated exosome miR-18a-5p promotes the initiation and development of CC by suppressing TMEM170B signaling axis, which provides a possible direction for the diagnosis and therapy of CC.

Searching for Essential Genes and Targeted Drugs Common to Breast Cancer and Osteoarthritis

BACKGROUND

It is documented that osteoarthritis can promote the progression of breast cancer (BC).

OBJECTIVE

This study aims to search for the essential genes associated with breast cancer (BC) and osteoarthritis (OA), explore the relationship between epithelial-mesenchymal transition (EMT)- related genes and the two diseases, and identify the candidate drugs.

METHODS

The genes related to both BC and OA were determined by text mining. Protein-protein Interaction (PPI) analysis was carried out, and as a result, the exported genes were found to be related to EMT. PPI and the correlation of mRNA of these genes were also analyzed. Different kinds of enrichment analyses were performed on these genes. A prognostic analysis was performed on these genes for examining their expression levels at different pathological stages, in different tissues, and in different immune cells. Drug-gene interaction database was employed for potential drug discovery.

RESULTS

A total number of 1422 genes were identified as common to BC and OA and 58 genes were found to be related to EMT. We found that HDAC2 and TGFBR1 were significantly poor in overall survival. High expression of HDAC2 plays a vital role in the increase of pathological stages. Four immune cells might play a role in this process. Fifty-seven drugs were identified that could potentially have therapeutic effects.

CONCLUSION

EMT may be one of the mechanisms by which OA affects BC. Using the drugs can have potential therapeutic effects, which may benefit patients with both diseases and broaden the indications for drug use.

Circadian clock and lipid metabolism disorders: a potential therapeutic strategy for cancer

Recent research has emphasized the interaction between the circadian clock and lipid metabolism, particularly in relation to tumors. This review aims to explore how the circadian clock regulates lipid metabolism and its impact on carcinogenesis. Specifically, targeting key enzymes involved in fatty acid synthesis (SREBP, ACLY, ACC, FASN, and SCD) has been identified as a potential strategy for cancer therapy. By disrupting these enzymes, it may be possible to inhibit tumor growth by interfering with lipid metabolism. Transcription factors, like SREBP play a significant role in regulating fatty acid synthesis which is influenced by circadian clock genes such as BMAL1, REV-ERB and DEC. This suggests a strong connection between fatty acid synthesis and the circadian clock. Therefore, successful combination therapy should target fatty acid synthesis in addition to considering the timing and duration of drug use. Ultimately, personalized chronotherapy can enhance drug efficacy in cancer treatment and achieve treatment goals.

Lanosterol Synthase Prevents EMT During Lens Epithelial Fibrosis Via Regulating SREBP1

Purpose

Epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is a predominant pathological process underlying fibrotic cataracts. Here we investigated the role and mechanism of lanosterol synthase (LSS), a key rate-limiting enzyme in sterol biosynthesis, in EMT of LECs.

Methods

Human lens epithelial explants, primary rabbit LECs, and whole rat lenses were treated with TGFβ2. RNA-sequencing was conducted to explore genetic changes during fibrosis of human lens epithelial explants. Loss- and gain-of-function studies were performed in primary LECs to investigate roles and mechanisms of LSS, lanosterol and sterol regulatory element binding transcription protein 1 (SREBP1) in EMT. Rat lenses were applied to evaluate the potential effect of lanosterol on lens fibrosis. Expression of LSS, SREBP1, EMT-related regulators, and markers were analyzed by Western blot, qRT-PCR, or immunofluorescent staining.

Results

LSS and steroid biosynthesis were downregulated in TGFβ2-induced lens fibrosis. LSS inhibition directly triggered EMT by inducing Smad2/3 phosphorylation and nucleus translocation, an overexpression of LSS protected LECs from EMT by inhibiting Smad2/3 activation. Moreover, LSS inhibition decreased the expression of SREBP1, which regulated EMT via intervening TGFβ2/Smad2/3 transduction. Furthermore, lanosterol protected LECs from EMT caused by both TGFβ2 treatment and LSS inhibition via suppressing Smad2/3 activation and maintained lens transparency by preventing fibrotic plaques formation.

Conclusions

We first identified that LSS protected LECs from EMT and played an antifibrotic role to maintain lens transparency. Additionally, lanosterol and sterol biosynthesis regulation might be promising strategies for preventing and treating fibrotic cataracts.

PROS1, a clinical prognostic biomarker and tumor suppressor, is associated with immune cell infiltration in breast cancer: A bioinformatics analysis combined with experimental verification

BACKGROUND

PROS1 is an encoding gene that can generate protein S. This protein is a glycoprotein found in plasma that conducts physiological functions with vitamin K. However, the impact of its expression remains absent in the progression and prognosis of breast cancer (BC).

METHODS

In this study, we comprehensively explored the expression of PROS1 in BC and its relationship with BC patient survival, prognosis, and other clinicopathological features. We investigated how PROS1 influenced the malignant biological behavior of BC cells. A series of enrichment analyses were conducted, and the immune landscape was explored in BC affected by PROS1. We also determined correlations between PROS1 and common drug sensitivities used for BC treatments.

RESULTS

PROS1 had low expression in BC, which tended to result in poor survival of BC patients. Overexpressed PROS1 inhibited the migration and invasion of BC cells as well as the epithelial-mesenchymal transition process by downregulating SNAIL. Functional enrichment analyses revealed that PROS1 was more active in extracellular matrix (ECM) organization and structural constituent, ECM-receptor interaction, and other pathways with its related genes. PROS1 was also found to affect immune activity, including various immune cells infiltrating BC. BC patients with high PROS1 expression tended to have lower IC50 values of three common medications and obtained better efficacy.

CONCLUSIONS

PROS1 can become a promising prognostic factor and a possible therapeutic target in BC patients and suppress BC cell metastatic potential. In addition, PROS1 is a crucial factor in immune infiltration in BC.

Prognostic significance of serum miR-18a-5p in severe COVID-19 Egyptian patients

BACKGROUND

The identification of miRNAs as well as characterization of miRNA-mRNA interactions in SARS-CoV-2 infection is important to understand their role in disease pathogenesis. Therefore the aim of the present study was to measure the expression levels of hsa-mir-18a-5p in the sera of severe COVID-19 Egyptian patients admitted to ICU to investigate its roles in the pathogenesis and severity of COVID-19 disease.

METHODS

A total of 180 unvaccinated severe COVID-19 patients were enrolled in our study. Besides the routine laboratory work, the expression level of hsa-mir-18a-5p was done using reverse transcription quantitative real-time PCR (RTqPCR) technique. Also, target genes of hsa-mir-18a-5p were explored by using online bioinformatics databases.

RESULTS

The expression level of hsa-mir-18a-5p decreased in nonsurvival severe COVID-19 patients (0.38 ± 0.26) when compared to the survival ones (0.84 ± 0.23). While as a prognostic tool for the prediction of bad prognosis and mortality among severe COVID-19 patients, our results showed that the serum hsa-mir-18a-5p expression level is a good sensitive and specific marker. By using bioinformatics tools, our results revealed that the decreased hsa-mir-18a-5p expression level may have a crucial role in COVID-19 pathogenesis and severity through decreased immunological responses (interpreted as lymphopenia) or increased inflammation (interpreted as increased serum levels of IL-6, CRP, LDH).

CONCLUSION

Taken together, the decreased expression level of hsa-mir-18a-5p could be a bad prognostic marker and therapeutic overexpression of hsa-mir-18a-5p could be a novel approach in the treatment of COVID-19 disease.

Gene profiles and mutations in the development of cataracts in the ICR rat model of hereditary cataracts

Cataracts are opacifications of the lens that cause loss of visual acuity and ultimately of eyesight. Age-related cataract develops in most elderly people, but the mechanisms of cataract onset are incompletely understood. The Ihara Cataract Rat (ICR) is an animal model of hereditary cataracts showing cortical opacity that commonly develops prematurely. We identified putative mechanisms of cataract onset in the ICR rat model by measuring gene expression changes before and after cortical cataract development and conducting point mutation analysis. Genes differentially expressed between 4-week-old animals without cortical cataracts and 8-10-week-old animals with cortical cataracts were selected from microarray analysis. Three connections were identified by STRING analysis: (i) Epithelial-Mesenchymal Transition (EMT), including Col1a2, and Pik3r1. (ii) Lens homeostasis, including Aqp5, and Cpm. (iii) Lipid metabolism, including Scd1, Srebf1, and Pnpla3. Subsequently, mutation points were selected by comparing ICR rats with 12 different rats that do not develop cataracts. The apolipoprotein Apoc3 was mutated in ICR rats. Analyses of gene expression changes and point and mutations suggested that abnormalities in EMT or lipid metabolism could contribute to cataract development in ICR rats.

ZFP64 Promotes Gallbladder Cancer Progression through Recruiting HDAC1 to Activate NOTCH1 Signaling Pathway

The lack of meaningful and effective early-stage markers remains the major challenge in the diagnosis of gallbladder cancer (GBC) and a huge barrier to timely treatment. Zinc finger protein 64 (ZFP64), a member of the zinc finger protein family, is considered to be a promising predictor in multiple tumors, but its potential effect in GBC still remains unclear. Here, we identified that ZFP64 was a vital regulatory protein in GBC. We found that ZFP64 expressed higher in GBC gallbladder carcinoma tissues than in normal tissues and was positively correlated with poor prognosis. Furthermore, ZFP64 was responsible for the migration, invasion, proliferation, anti-apoptosis, and epithelial mesenchymal transition (EMT) of GBC cells in vitro and in vivo. Mechanistically, through Co-IP assay, we confirmed that ZFP64 recruits HDAC1 localized to the promoter region of NUMB for deacetylation and therefore inhibits NUMB expression. The downregulation of NUMB enhanced the activation of the Notch1 signaling pathway, which is indispensable for the GBC-promotion effect of ZFP64 on GBC. In conclusion, ZFP64 regulated GBC progression and metastasis through upregulating the Notch1 signaling pathway, and thus ZFP64 is expected to become a new focus for a GBC prognostic marker and targeted therapy.

Single-cell transcriptome analysis indicates fatty acid metabolism-mediated metastasis and immunosuppression in male breast cancer

Male breast cancer (MBC) is a rare but aggressive malignancy with cellular and immunological characteristics that remain unclear. Here, we perform transcriptomic analysis for 111,038 single cells from tumor tissues of six MBC and thirteen female breast cancer (FBC) patients. We find that that MBC has significantly lower infiltration of T cells relative to FBC. Metastasis-related programs are more active in cancer cells from MBC. The activated fatty acid metabolism involved with FASN is related to cancer cell metastasis and low immune infiltration of MBC. T cells in MBC show activation of p38 MAPK and lipid oxidation pathways, indicating a dysfunctional state. In contrast, T cells in FBC exhibit higher expression of cytotoxic markers and immune activation pathways mediated by immune-modulatory cytokines. Moreover, we identify the inhibitory interactions between cancer cells and T cells in MBC. Our study provides important information for understanding the tumor immunology and metabolism of MBC.

Schisandrin treatment suppresses the proliferation, migration, invasion, and inflammatory responses of fibroblast-like synoviocytes from rheumatoid arthritis patients and attenuates synovial inflammation and joint destruction in CIA mice

BACKGROUND

Rheumatoid arthritis (RA) is a systemic autoimmune disease causing joint dysfunction. As disease-modifying anti-rheumatic drugs (DMARDs) have poor efficacy in 20% to 25% of RA patients, additional novel RA medications are urgently needed. Schisandrin (SCH) has multiple therapeutic effects. However, whether SCH is effective against RA remains unknown.

PURPOSE

To investigate how SCH affects the abnormal behaviours of RA fibroblast-like synoviocytes (FLSs) and further elucidate the underlying mechanism of SCH in RA FLSs and collagen-induced arthritis (CIA) mice.

METHODS

Cell Counting Kit-8 (CCK8) assays were used to characterize cell viability. EdU assays were performed to assess cell proliferation. Annexin V-APC/PI assays were used to determine apoptosis. Transwell chamber assays were used to measure cell migration and invasion in vitro. RT-qPCR was used to assess proinflammatory cytokine and MMP mRNA expression. Western blotting was used to detect protein expression. RNA sequencing was performed to explore the potential downstream targets of SCH. CIA model mice were used to assess the treatment efficacy of SCH in vivo.

RESULTS

Treatments with SCH (50, 100, and 200 μΜ) inhibited RA FLSs proliferation, migration, invasion, and TNF-α-induced IL-6, IL-8, and CCL2 expression in a dose-dependent manner but did not affect RA FLSs viability or apoptosis. RNA sequencing and Reactome enrichment analysis indicated that SREBF1 might be the downstream target in SCH treatment. Furthermore, knockdown of SREBF1 exerted effects similar to those of SCH in inhibiting RA FLSs proliferation, migration, invasion, and TNF-α-induced expression of IL-6, IL-8, and CCL2. Both SCH treatment and SREBF1 knockdown decreased activation of the PI3K/AKT and NF-κB signalling pathways. Moreover, SCH ameliorated joint inflammation and cartilage and bone destruction in CIA model mice.

CONCLUSION

SCH controls the pathogenic behaviours of RA FLSs by targeting SREBF1-mediated activation of the PI3K/AKT and NF-κB signalling pathways. Our data suggest that SCH inhibits FLS-mediated synovial inflammation and joint damage and that SCH might have therapeutic potential for RA.

Exosomal miR-18a-5p promotes EMT and metastasis of NPC cells via targeting BTG3 and activating the Wnt/β-catenin signaling pathway

This study investigated the underlying mechanism of miR-18a-5p regulating the proliferation, invasion, and metastasis of nasopharyngeal carcinoma (NPC) cells in vitro and in vivo to indicate the pathogenesis of NPC. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was utilized to determine miR-18a-5p expression level in NPC tissues and cell lines. Besides, 2,5-diphenyl-2 H-tetrazolium bromide (MTT) and colony formation assays were employed to detect the effect of miR-18a-5p expression level on NPC cell proliferation. Wound healing and Transwell assays were utilized to detect the effect of miR-18a-5p on NPC cell invasion and migration. The expression levels of epithelial-mesenchymal transition (EMT)-related proteins (Vimentin, N-cadherin, and E-cadherin) were identified by Western blot assay. After collecting exosomes from CNE-2 cells, it was found that exosomal miR-18a-5p secreted from NPC cells promoted NPC cell proliferation, migration, invasion, and EMT, whereas inhibition of miR-18a-5p expression level led to the opposite results. The dual-luciferase reporter assay showed that BTG anti-proliferation factor 3 (BTG3) was the target gene of miR-18a-5p, and BTG3 could overturn the effect of miR-18a-5p on NPC cells. Xenograft mouse model of NPC nude mice showed that miR-18a-5p promoted NPC growth and metastasis in vivo. This study revealed that exosomal miR-18a-5p derived from NPC cells promoted angiogenesis via targeting BTG3 and activating the Wnt/β-catenin signaling pathway.

Hsa-miR-301a-3p inhibited the killing effect of natural killer cells on non-small cell lung cancer cells by regulating RUNX3

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most commonly diagnosed solid tumor. Natural killer (NK) cell-based immunotherapy is a promising anti-tumor strategy in various cancers including NSCLC.

OBJECTIVE

We aimed to investigate the specific mechanisms that regulate the killing effect of NK cells to NSCLC cells.

METHODS

Reverse transcription-quantitative PCR (RT-qPCR) assay was applied to measure the levels of hsa-microRNA (miR)-301a-3p and Runt-related transcription factor 3 (RUNX3). Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of IFN-γ and TNF-α. Lactate dehydrogenase assay was applied to detect the killing effect of NK cells. Dualluciferase reporter assay and RNA immunoprecipitation (RIP) assay were carried out to confirm the regulatory relationship between hsa-miR-301a-3p and RUNX3.

RESULTS

A low expression of hsa-miR-301a-3p was observed in NK cells stimulated by IL-2. The levels of IFN-γ and TNF-α were increased in NK cells of the IL-2 group. Overexpression of hsa-miR-301a-3p reduced the levels of IFN-γ and TNF-α as well as the killing effect of NK cells. Furthermore, RUNX3 was identified to be a target of hsamiR-301a-3p. hsa-miR-301a-3p suppressed the cytotoxicity of NK cells to NSCLC cells by inhibiting the expression of RUNX3. We found hsa-miR-301a-3p promoted tumor growth by suppressing the killing effect of NK cells against NSCLC cells in vivo.

CONCLUSIONS

Hsa-miR-301a-3p suppressed the killing effect of NK cells on NSCLC cells by targeting RUNX3, which may provide promising strategies for NK cell-based antitumor therapies.

Comprehensively prognostic and immunological analysis of snail family transcriptional repressor 2 in pan-cancer and identification in pancreatic carcinoma

Background

Snail family transcriptional repressor 2 (SNAI2) is a transcription factor that induces epithelial to mesenchymal transition in neoplastic epithelial cells. It is closely related to the progression of various malignancies. However, the significance of SNAI2 in human pan-cancer is still largely unknown.

Methods

The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Cancer Cell Line Encyclopedia (CCLE) databases were taken to examine the SNAI2 expression pattern in tissues and cancer cells. The link between SNAI2 gene expression levels and prognosis, as well as immune cell infiltration, was investigated using the Kaplan-Meier technique and Spearman correlation analysis. We also explored the expression and distribution of SNAI2 in various tumor tissues and cells by the THPA (Human Protein Atlas) database. We further investigated the relationship between SNAI2 expression levels and immunotherapy response in various clinical immunotherapy cohorts. Finally, the immunoblot was used to quantify the SNAI2 expression levels, and the proliferative and invasive ability of pancreatic cancer cells was determined by colony formation and transwell assays.

Results

We discovered heterogeneity in SNAI2 expression in different tumor tissues and cancer cell lines by exploring public datasets. The genomic alteration of SNAI2 existed in most cancers. Also, SNAI2 exhibits prognosis predictive ability in various cancers. SNAI2 was significantly correlated with immune-activated hallmarks, cancer immune cell infiltrations, and immunoregulators. It's worth noting that SNAI2 expression is significantly related to the effectiveness of clinical immunotherapy. SNAI2 expression was also found to have a high correlation with the DNA mismatch repair (MMR) genes and DNA methylation in many cancers. Finally, the knockdown of SNAI2 significantly weakened the proliferative and invasive ability of pancreatic cancer cells.

Conclusion

These findings suggested that SNAI2 could be used as a biomarker in human pan-cancer to detect immune infiltration and poor prognosis, which provides a new idea for cancer treatment.

Deciphering the role of MitomiRs in cancer: A comprehensive review

MicroRNAs (miRNAs) are short non-coding RNAs that regulate many metabolic and signal transduction pathways. The role of miRNAs, usually found in the cytoplasm, in regulating gene expression and cancer progression has been extensively studied in the last few decades. However, very recently, miRNAs were found to localize in the mitochondria. MiRNAs that specifically localize in the mitochondria and the cytoplasmic miRNAs associated with mitochondria that directly or indirectly modulate specific mitochondrial functions are termed as "mitomiRs". Although it is not clear about the origin of mitomiRs that are situated within mitochondria (nuclear or mitochondrial origin), it is evident that they have specific functions in modulating gene expression and regulating important mitochondrial metabolic pathways. Through this review, we aim to delineate the mechanisms by which mitomiRs alter mitochondrial metabolic pathways and influence the initiation and progression of cancer. We further discuss the functions of particular mitomiRs, which have been widely studied in the context of mitochondrial metabolism and oncogenic signaling pathways. Based on the current knowledge, we can conclude that mitomiRs contribute significantly to mitochondrial function and metabolic regulation, and that dysregulation of mitomiRs can aid the proliferation of cancer cells. Therefore, the less explored area of mitomiRs' biology can be an important topic of research investigation in the future for targeting cancer cells.

Targeting KK-LC-1 inhibits malignant biological behaviors of triple-negative breast cancer

BACKGROUND

Cancer/testis antigens (CTAs) participate in the regulation of malignant biological behaviors in breast cancer. However, the function and mechanism of KK-LC-1, a member of the CTA family, in breast cancer are still unclear.

METHODS

Bioinformatic tools, immunohistochemistry, and western blotting were utilized to detect the expression of KK-LC-1 in breast cancer and to explore the prognostic effect of KK-LC-1 expression in breast cancer patients. Cell function assays, animal assays, and next-generation sequencing were utilized to explore the function and mechanism of KK-LC-1 in the malignant biological behaviors of triple-negative breast cancer. Small molecular compounds targeting KK-LC-1 were also screened and drug susceptibility testing was performed.

RESULTS

KK-LC-1 was significantly highly expressed in triple-negative breast cancer tissues than in normal breast tissues. KK-LC-1 high expression was related to poor survival outcomes in patients with breast cancer. In vitro studies suggested that KK-LC-1 silencing can inhibit triple-negative breast cancer cell proliferation, invasion, migration, and scratch healing ability, increase cell apoptosis ratio, and arrest the cell cycle in the G0-G1 phase. In vivo studies have suggested that KK-LC-1 silencing decreases tumor weight and volume in nude mice. Results showed that KK-CL-1 can regulate the malignant biological behaviors of triple-negative breast cancer via the MAL2/MUC1-C/PI3K/AKT/mTOR pathway. The small-molecule compound Z839878730 had excellent KK-LC-1 targeting ability and cancer cell killing ability. The EC₅₀ value was 9.7 μM for MDA-MB-231 cells and 13.67 µM for MDA-MB-468 cells. Besides, Z839878730 has little tumor-killing effect on human normal mammary epithelial cells MCF10A and can inhibit the malignant biological behaviors of triple-negative breast cancer cells by MAL2/MUC1-C/PI3K/AKT/mTOR pathway.

CONCLUSIONS

Our findings suggest that KK-LC-1 may serve as a novel therapeutic target for triple-negative breast cancer. Z839878730, which targets KK-LC-1, presents a new path for breast cancer clinical treatment.

A universal ratiometric method for Micro-RNA detection based on the ratio of electrochemical/electrochemiluminescence signal, and toehold-mediated strand displacement amplification

An ultra-selective and reproductive ratiometric platform was introduced based on the ratio of Ru(phen)₃²⁺ electrochemiluminescence (ECL) signal and methylene blue (MB) electrochemistry (EC) signal, which was amplified using a specific and efficient toehold-mediated strand displacement (TMSD). The stable DNA nanoclews (NCs) were efficiently loaded with MB (MB-NCs) as EC signal tags after being synthesized utilizing a simple rolling circle amplification reaction. Besides, Ti₃C₂-based nanocomposite could apply as a superb carrier for both Ru(phen)₃²⁺ and gold nanoparticles (Ti₃C₂-Au-Ru), resulting in a nearly constant ECL internal reference to eliminate the possible interferences. The Ti₃C₂-Au-Ru was attached to the surface of the electrode using Nafion, which exhibited excellent conductivity, and hairpin DNAs (hDNAs) were fixed on AuNPs via an Au-S bond. The designed biosensor was finally applied for miRNA-18a detection as a target model. The TMSD method made it possible to concurrently convert and amplify a single miRNA-18ainput into a large amount of output DNAs with high selectivity. These output DNAs were designed to unfold the stem-locked area of hDNAs. The opened hDNAs then hybridized with the MB-NCs to produce an EC signal. In the proposed biosensing system, by raising the target concentration of miRNA, the EC signal gradually rose, the ECL signal remained nearly constant, and the ratiometric detection method markedly promoted biosensor accuracy. Linear correlations of the ratio value of the EC/ECL with miRNA-18a concentrations between 20 aM and 50 pMwere observed, with the limit of detection of 9 aM. The biosensor was applied to detect miRNA-18a in real serum samples with satisfactory results.

Regorafenib enhances anti-tumor efficacy of immune checkpoint inhibitor by regulating IFN-γ/NSDHL/SREBP1/TGF-β1 axis in hepatocellular carcinoma

Immune checkpoint inhibitor (ICI) shows low response rate in hepatocellular carcinoma (HCC) but the mechanisms underlying ICI resistance remains unclear. Interferon-γ (IFN-γ) has been widely determined as a prototypical antitumor cytokine. However, growing studies suggest that IFN-γ also mediates immunosuppression to promote tumor progression. Herein, we explored whether ICI-induced IFN-γ could activate immunosuppressive TGF-β1 to mediate ICI resistance. We demonstrated that cholesterol biosynthetic enzyme, NSDHL, was decreased in HCC tissues and associated with poor clinical prognosis. ICI-induced IFN-γ decreased NSDHL to activate SREBP1, which promoted TGF-β1 production, reduced T cell toxicity and enhanced Tregs infiltration, leading to ICI resistance. We also found that novel tyrosine kinase inhibitor, regorafenib, significantly reverse the above immunosuppressive effects by regulating NSDHL/SREBP1/TGF-β1 axis, which strengthened the effects of regorafenib plus ICI therapy against HCC. Noteworthily, regorafenib plus ICI therapy was more effective in HCC patients with higher serum TGF-β1. In conclusion, IFN-γ induced TGF-β1 to mediate ICI resistance. Regorafenib promotes anti-tumor immune response of ICI by regulating IFN-γ/NSDHL/SREBP1/TGF-β1 axis. Serum TGF-β1 may serve as a biomarker for predicting efficacy of regorafenib plus ICI therapy in HCC.

ncR2Met (lncR2metasta v2.0): An updated database for experimentally supported ncRNAs during cancer metastatic events

Non-coding RNAs (ncRNAs) are widely involved in cancer metastatic events (CMEs, e.g., cancer cell invasion, intravasation, extravasation, proliferation), which collaboratively accelerate tumor spread and cause high patient mortality. In early 2020, we developed a manually curated database named 'lncR2metasta' to provide a comprehensive repository for long ncRNA (lncRNA) regulation during CMEs. We updated this database by supplementing other two important ncRNA types, microRNAs (miRNAs) and circular RNAs (circRNAs), for their involvement during CMEs after a thorough manual curation from published studies. ncR2metasta documents 1565 lncRNA-associated, 882 miRNA-associated, and 628 circRNA-associated entries for ncRNA-CME associations during 50 CMEs across 63 human cancer subtypes. ncR2Met has a concise web interface for researchers to easily browse, search and download as well as to submit novel ncRNA-CME associations. We anticipated that it could be a valuable resource, which will significantly improve our understanding of ncRNA functions in metastasis. It is freely available at http://ncr2met.wchoda.com.

Modulation of AKT Pathway-Targeting miRNAs for Cancer Cell Treatment with Natural Products

Many miRNAs are known to target the AKT serine-threonine kinase (AKT) pathway, which is critical for the regulation of several cell functions in cancer cell development. Many natural products exhibiting anticancer effects have been reported, but their connections to the AKT pathway (AKT and its effectors) and miRNAs have rarely been investigated. This review aimed to demarcate the relationship between miRNAs and the AKT pathway during the regulation of cancer cell functions by natural products. Identifying the connections between miRNAs and the AKT pathway and between miRNAs and natural products made it possible to establish an miRNA/AKT/natural product axis to facilitate a better understanding of their anticancer mechanisms. Moreover, the miRNA database (miRDB) was used to retrieve more AKT pathway-related target candidates for miRNAs. By evaluating the reported facts, the cell functions of these database-generated candidates were connected to natural products. Therefore, this review provides a comprehensive overview of the natural product/miRNA/AKT pathway in the modulation of cancer cell development.

Meso-Hannokinol inhibits breast cancer bone metastasis via the ROS/JNK/ZEB1 axis

Distal metastases from breast cancer, especially bone metastases, are extremely common in the late stages of the disease and are associated with a poor prognosis. EMT is a biomarker of the early process of bone metastasis, and MMP-9 and MMP-13 are important osteoclastic activators. Previously, we found that meso-Hannokinol (HA) could significantly inhibit EMT and MMP-9 and MMP-13 expressions in breast cancer cells. On this basis, we further explored the role of HA in breast cancer bone metastasis. In vivo, we established a breast cancer bone metastasis model by intracardially injecting breast cancer cells. Intraperitoneal injections of HA significantly reduced breast cancer cell metastasis to the leg bone in mice and osteolytic lesions caused by breast cancer. In vitro, HA inhibited the migration and invasion of breast cancer cells and suppressed the expressions of EMT, MMP-9, MMP-13, and other osteoclastic activators. HA inhibited EMT and MMP-9 by activating the ROS/JNK pathway as demonstrated by siJNK and SP600125 inhibition of JNK phosphorylation and NAC scavenging of ROS accumulation. Moreover, HA promoted bone formation and inhibited bone resorption in vitro. In conclusion, our findings suggest that HA may be an excellent candidate for treating breast cancer bone metastasis.

Targeting lipid metabolism for ferroptotic cancer therapy

It has been 10 years since the concept of ferroptosis was put forward and research focusing on ferroptosis has been increasing continuously. Ferroptosis is driven by iron-dependent lipid peroxidation, which can be antagonized by glutathione peroxidase 4 (GPX4), ferroptosis inhibitory protein 1 (FSP1), dihydroorotate dehydrogenase (DHODH) and Fas-associated factor 1 (FAF1). Various cellular metabolic events, including lipid metabolism, can modulate ferroptosis sensitivity. It is worth noting that the reprogramming of lipid metabolism in cancer cells can promote the occurrence and development of tumors. The metabolic flexibility of cancer cells opens the possibility for the coordinated targeting of multiple lipid metabolic pathways to trigger cancer cells ferroptosis. In addition, cancer cells must obtain immortality, escape from programmed cell death including ferroptosis, to promote cancer progression, which provides new perspectives for improving cancer therapy. Targeting the vulnerability of ferroptosis has received attention as one of the significant possible strategies to treat cancer given its role in regulating tumor cell survival. We review the impact of iron and lipid metabolism on ferroptosis and the potential role of the crosstalk of lipid metabolism reprogramming and ferroptosis in antitumor immunity and sum up agents targeting lipid metabolism and ferroptosis for cancer therapy.

Regulation of osteogenesis in bone marrow-derived mesenchymal stem cells via histone deacetylase 1 and 2 co-cultured with human gingival fibroblasts and periodontal ligament cells

OBJECTIVE

This study aimed to determine the regulatory mechanism of bone marrow-derived mesenchymal stem cell (BM-MSC) differentiation mediated by humoral factors derived from human periodontal ligament (HPL) cells and human gingival fibroblasts (HGFs). We analyzed histone deacetylase (HDAC) expression and activity involved in BM-MSC differentiation and determined their regulatory effects in co-cultures of BM-MSCs with HPL cells or HGFs.

BACKGROUND

BM-MSCs can differentiate into various cell types and can, thus, be used in periodontal regenerative therapy. However, the mechanism underlying their differentiation remains unclear. Transplanted BM-MSCs are affected by periodontal cells via direct contact or secretion of humoral factors. Therefore, their activity is regulated by humoral factors derived from HPL cells or HGFs.

METHODS

BM-MSCs were indirectly co-cultured with HPL cells or HGFs under osteogenic or growth conditions and then analyzed for osteogenesis, HDAC1 and HDAC2 expression and activity, and histone H3 acetylation. BM-MSCs were treated with trichostatin A, or their HDAC1 or HDAC2 expression was silenced or overexpressed during osteogenesis. Subsequently, they were evaluated for osteogenesis or the effects of HDAC activity.

RESULTS

BM-MSCs co-cultured with HPL cells or HGFs showed suppressed osteogenesis, HDAC1 and HDAC2 expression, and HDAC phosphorylation; however, histone H3 acetylation was enhanced. Trichostatin A treatment remarkably suppressed osteogenesis, decreasing HDAC expression and enhancing histone H3 acetylation. HDAC1 and HDAC2 silencing negatively regulated osteogenesis in BM-MSCs to the same extent as that achieved by indirect co-culture with HPL cells or HGFs. Conversely, their overexpression positively regulated osteogenesis in BM-MSCs.

CONCLUSION

The suppressive effects of HPL cells and HGFs on BM-MSC osteogenesis were regulated by HDAC expression and histone H3 acetylation to a greater extent than that mediated by HDAC activity. Therefore, regulation of HDAC expression has prospects in clinical applications for effective periodontal regeneration, mainly, bone regeneration.

Targeting SLP2-mediated lipid metabolism reprograming restricts proliferation and metastasis of hepatocellular carcinoma and promotes sensitivity to Lenvatinib

SLP2, a protein located on mitochondrial, has been shown to be associated with mitochondrial biosynthesis. Here we explored the potential mechanisms by which SLP2 regulates the development of hepatocellular carcinoma. SLP2 could bind to the c-terminal of JNK2 to affect the ubiquitinated proteasomal degradation pathway of JNK2 and maintain the protein stability of JNK2. The increase of JNK2 markedly increases SREBP1 activity, promoting SREBP1 translocation into the nucleus to promote de novo lipogenesis. Alteration of the JNK2 C-terminal disables SLP2 from mediating SLP2-enhanced de novo lipogenesis. YTHDF1 interacts with SLP2 mRNA in a METTL3/m⁶A-dependent manner. In a spontaneous HCC animal model, SLP2/c-Myc/sgP53 increases the incidence rate of spontaneous HCC, tumor volume, and tumor number. Importantly, statistical analyses show that levels of SLP2 correlate with tumor sizes, tumor metastasis, overall survival, and disease-free survival of the patients. Targeting the SLP2/SREBP1 pathway effectively inhibits proliferation and metastasis of HCC tumors with high SLP2 expression in vivo combined with lenvatinib. These results illustrate a direct lipogenesis-promoting role of the pro-oncogenic SLP2, providing a mechanistic link between de novo lipogenesis and HCC.

Sterol regulatory element binding transcription factor 1 promotes proliferation and migration in head and neck squamous cell carcinoma

Background

Sterol-regulatory element-binding protein 1 (SREBP1) is a transcription factor involved in lipid metabolism that is encoded by sterol regulatory element binding transcription factor 1(SREBF1). SREBP1 overexpression is associated with the progression of several human tumors; however, the role of SREBP1 in head and neck squamous cell carcinoma (HNSC) remains unclear.

Methods

SREBF1 expression in pan-cancer was analyzed using the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data, and the association between SREBF1 expression and clinical characteristics of HNSC patients was examined using the UALCAN database. Enrichment analysis of SREBF1-related genes was performed using the Cluster Profiler R package. TCGA database was used to investigate the relationship between immune cell infiltration and SREBF1 expression. CCK-8, flow cytometry, and wound healing assays were performed to investigate the effect of SREBF1 knockdown on the proliferation and migration of HNSC cells.

Results

SREBF1 was significantly upregulated in several tumor tissues, including HNSC, and SREBF1 overexpression was positively correlated with sample type, cancer stage, tumor grade, and lymph node stage in HNSC patients. Gene enrichment analysis revealed that SREBF1 is associated with DNA replication and homologous recombination. SREBF1 upregulation was positively correlated with the infiltration of cytotoxic cells, B cells, T cells, T helper cells, and NK CD56 bright cells in HNSC. Knockdown of SREBF1 inhibited the proliferation and migration of HNSC cells (Hep2 and TU212) and induced apoptosis by downregulating the expression of steroidogenic acute regulatory protein-related lipid transfer 4 (STARD4).

Conclusions

SREBF1 may promote HNSC proliferation, migration and inhibit apoptosis by upregulating STARD4 and affecting the level of immune cell infiltration.

Type XXVIII Collagen Regulates Renal Interstitial Fibrosis and Epithelial-Mesenchymal Transition by SREBP1-Mediated HKDC1 Expression

Background. A novel collagen called type XXVIII collagen (COL28) is involved in cancer and lung fibrosis. Preliminary data showed that renal tubular epithelial cells could proliferate, migrate, and undergo an epithelial-mesenchymal transition (EMT) when COL28 was overexpressed; however, it is still unknown how this occurs and what the underlying mechanism is. Methods. We analyzed the differential expression of genes (DEGs) in the stable COL28 overexpression HK-2 cell lines by RNA-sequencing analysis, before which Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) analyses were performed. Genes related to COL28 promoting HK-2 cell proliferation and EMT were screened and verified. By using western blot and immunofluorescence, the effects of COL28 on the expression of α-SMA, E-cadherin, Snail, HKDC1, and SREBP1 were detected. The effect of COL28 overexpression on renal fibrosis in unilateral ureteral obstruction (UUO) mice was detected by H&E and Masson staining. HKDC1 interference agent was synthesized and transfected into the HK-2 cell line stably overexpressing COL28. In HK-2 cells, the effects of HKDC1 interference on the expression of α-SMA, E-cadherin, and Snail were detected. Results. We screened and verified that HKDC1 was related to COL28 and promoted HK-2 cell proliferation and EMT. WB showed that in HK-2 cells, COL28 overexpression increased α-SMA, Snail, HKDC1, and SREBP1 expressions and decreased E-cadherin expression. Overexpression of COL28 aggravated renal interstitial fibrosis in UUO mice; upregulated α-SMA, Snail, HKDC1, and SREBP1 expressions; and decreased the E-cadherin protein expression in UUO mice. Interference of HKDC1 expression promoted the E-cadherin protein expression while inhibiting α-SMA, Snail, HKDC1, and SREBP1 protein expressions. Conclusion. Overexpression of COL28 can aggravate renal interstitial fibrosis by encouraging renal tubular epithelial cells to undergo EMT, and interference with HKDC1 expression can alleviate fibrosis by reversing EMT induced by COL28 overexpression.

ZBTB18 inhibits SREBP-dependent lipid synthesis by halting CTBPs and LSD1 activity in glioblastoma

Enhanced fatty acid synthesis is a hallmark of tumors, including glioblastoma. SREBF1/2 regulate the expression of enzymes involved in fatty acid and cholesterol synthesis. Yet, little is known about the precise mechanism regulating SREBP gene expression in glioblastoma. Here, we show that a novel interaction between the co-activator/co-repressor CTBP and the tumor suppressor ZBTB18 regulates the expression of SREBP genes. In line with our findings, metabolic assays and glucose tracing analysis confirm the reduction in several phospholipid species upon ZBTB18 expression. Our study identifies CTBP1/2 and LSD1 as co-activators of SREBP genes and indicates that the functional activity of the CTBP-LSD1 complex is altered by ZBTB18. ZBTB18 binding to the SREBP gene promoters is associated with reduced LSD1 demethylase activity of H3K4me2 and H3K9me2 marks. Concomitantly, the interaction between LSD1, CTBP, and ZNF217 is increased, suggesting that ZBTB18 promotes LSD1 scaffolding function. Our results outline a new epigenetic mechanism enrolled by ZBTB18 and its co-factors to regulate fatty acid synthesis that could be targeted to treat glioblastoma patients.

A quantitative structural analysis of AR-42 derivatives as HDAC1 inhibitors for the identification of promising structural contributors

Alteration and abnormal epigenetic mechanisms can lead to the aberration of normal biological functions and the occurrence of several diseases. The histone deacetylase (HDAC) family of enzymes is one of the prime regulators of epigenetic functions modifying the histone proteins, and thus, regulating epigenetics directly. HDAC1 is one of those HDACs which have important contributions to cellular epigenetics. The abnormality of HDAC is correlated to the occurrence, progression, and poor prognosis in several disease conditions namely neurodegenerative disorders, cancer cell proliferation, metastasis, chemotherapy resistance, and survival in various cancers. Therefore, the progress of potent and effective HDAC1 inhibitors is one of the prime approaches to combat such diseases. In this study, both regression and classification-based molecular modelling studies were conducted on some AR-42 derivatives as HDAC1 inhibitors to elucidate the crucial structural aspects that are responsible for regulating their biological responses. This study revealed that the molecular polarizability, van der Waals volume, the presence of aromatic rings as well as the higher number of hydrogen bond acceptors might affect prominently their inhibitory activity and might be responsible for proper fitting and interactions at the HDAC1 active site to pertain effective inhibition.

The NQO1/p53/SREBP1 axis promotes hepatocellular carcinoma progression and metastasis by regulating Snail stability

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide, and its abnormal metabolism affects the survival and prognosis of patients. Recent studies have found that NAD(P)H quinone oxidoreductase-1 (NQO1) played an important role in tumor metabolism and malignant progression. However, the molecular mechanisms by which NQO1 regulates lipid metabolism during HCC progression remain unclear. In this study, bioinformatics analysis and immunohistochemical results showed that NQO1 was highly expressed in HCC tissues and its high expression was closely related to the poor prognosis of HCC patients. Overexpression of NQO1 promoted the cell proliferation, epithelial-to-mesenchymal transition (EMT) process, and angiogenesis of HCC cells. Luciferase reporter assay further revealed that NQO1/p53 could induce the transcriptional activity of SREBP1, consequently regulating HCC progression through lipid anabolism. In addition, Snail protein was stabilized by NQO1/p53/SREBP1 axis and triggered the EMT process, and participated in the regulatory role of NQO1/p53/SREBP1 axis in HCC. Together, these data indicated that NQO1/SREBP1 axis promoted the progression and metastasis of HCC, and might be a potential therapeutic target for HCC.

Leonurine suppresses prostate cancer growth in vitro and in vivo by regulating miR-18a-5p/SLC40A1 axis

Prostate cancer is a leading cause of cancer-associated death in males. Leonurine (Leo) is a pleiotropic anti-tumor agent isolated from traditional Chinese herb that was used in gynecologic treatments. However, its pharmacological effect against prostate cancer progression remains unclear. Here, we showed that Leo dose dependently inhibited prostate cancer cell proliferation, promoted cell apoptosis, and induced cell cycle arrest. Moreover, we noticed that miR-18a-5p was downregulated and the solute carrier family 40 member 1 (SLC40A1) is upregulated by Leo treatment. SLC40A1 knockdown by siRNA abrogated the inhibitory effect of Leo on prostate cancer progression. Notably, Leo also significantly inhibited prostate cancer progression in a subcutaneous xenograft tumor mouse model in vivo. This study further unveiled the mechanism by which Leo inhibited prostate cancer progression, which provides a promising potential for its future clinical application.

Circ-TRIO promotes TNBC progression by regulating the miR-432-5p/CCDC58 axis

Numerous studies have shown that circRNAs are aberrantly expressed in various cancers and play a significant role in tumor progression. However, the molecular mechanisms of circRNAs in triple-negative breast cancer (TNBC) remain ambiguous. By intersecting throughput data and qRT-PCR results from tissues and cell lines, circ-TRIO was identified as a potential oncogenic regulator of TNBC. Moreover, circ-TRIO expression was detected in TNBC tissues and was correlated with the recurrence and prognosis of TNBC patients. The circular characteristics of circ-TRIO were verified by RNase R and CHX assays. Functionally, the knockdown of circ-TRIO inhibited the proliferation, migration and invasion of TNBC cells, while the overexpression of circ-TRIO resulted in the opposite impacts. Mechanistically, a dual luciferase reporter assay and RNA immunoprecipitation were performed and indicated that circ-TRIO could combine with miR-432-5p to regulate the expression of coiled-coil domain containing 58 (CCDC58). In summary, our study illustrates that circ-TRIO plays an important role in the progression of TNBC by regulating the miR-432-5p/CCDC58 axis, which could broaden our insight into the underlying mechanisms and provide a novel prognostic marker of TNBC in the clinic.

Targeting SREBP-1-Mediated Lipogenesis as Potential Strategies for Cancer

Sterol regulatory element binding protein-1 (SREBP-1), a transcription factor with a basic helix–loop–helix leucine zipper, has two isoforms, SREBP-1a and SREBP-1c, derived from the same gene for regulating the genes of lipogenesis, including acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase. Importantly, SREBP-1 participates in metabolic reprogramming of various cancers and has been a biomarker for the prognosis or drug efficacy for the patients with cancer. In this review, we first introduced the structure, activation, and key upstream signaling pathway of SREBP-1. Then, the potential targets and molecular mechanisms of SREBP-1-regulated lipogenesis in various types of cancer, such as colorectal, prostate, breast, and hepatocellular cancer, were summarized. We also discussed potential therapies targeting the SREBP-1-regulated pathway by small molecules, natural products, or the extracts of herbs against tumor progression. This review could provide new insights in understanding advanced findings about SREBP-1-mediated lipogenesis in cancer and its potential as a target for cancer therapeutics.

The Role of MicroRNA in the Regulation of Tumor Epithelial–Mesenchymal Transition

Consistently, the high metastasis of cancer cells is the bottleneck in the process of tumor treatment. In this process of metastasis, a pivotal role is executed by epithelial–mesenchymal transition (EMT). The epithelial-to-mesenchymal transformation was first proposed to occur during embryonic development. Later, its important role in explaining embryonic developmental processes was widely reported. Recently, EMT and its intermediate state were also identified as crucial drivers in tumor progression with the gradual deepening of research. To gain insights into the potential mechanism, increasing attention has been focused on the EMT-related transcription factors. Correspondingly, miRNAs target transcription factors to control the EMT process of tumor cells in different types of cancers, while there are still many exciting and challenging questions about the phenomenon of microRNA regulation of cancer EMT. We describe the relevant mechanisms of miRNAs regulating EMT, and trace the regulatory roles and functions of major EMT-related transcription factors, including Snail, Twist, zinc finger E-box-binding homeobox (ZEB), and other families. In addition, on the basis of the complex regulatory network, we hope that the exploration of the regulatory relationship of non-transcription factors will provide a better understanding of EMT and cancer metastasis. The identification of the mechanism leading to the activation of EMT programs during diverse disease processes also provides a new protocol for the plasticity of distinct cellular phenotypes and possible therapeutic interventions. Here, we summarize the recent progress in this direction, with a promising path for further insight into this fast-moving field.

CILP, a Putative Gene Associated With Immune Infiltration in Breast Cancer Brain Metastases

Breast cancer (BC) is the second leading cause of brain metastases (BM), with high morbidity and mortality. The aim of our study was to explore the effect of the cartilage intermediate layer protein (CILP) on breast cancer brain metastases (BCBM). Using a weighted gene coexpression network analysis (WGCNA) in GSE100534 and GSE125989 datasets, we found that the yellow module was closely related to the occurrence of BCBM, and CILP was a hub gene in the yellow module. Low CILP expression was associated with a poor prognosis, and it was an independent prognostic factor for stage III-IV BC determined using Cox regression analysis. A nomogram model including CILP expression was established to predict the 5-, 7-, and 10-year overall survival (OS) probabilities of stage III-IV BC patients. We found that CILP mRNA expression was downregulated in BCBM through GSE100534, GSE125989, and GSE43837 datasets. In addition, we found that CILP mRNA expression was negatively correlated with vascular endothelial growth factor A (VEGFA), which is involved in regulating the development of BM. UALCAN analysis showed that CILP expression was downregulated in HER2-positive (HER2+) and triple-negative breast cancer (TNBC), which are more prone to BM. The vitro experiments demonstrated that CILP significantly inhibited BC cell proliferation and metastasis. Western blot (WB) results further showed that the mesenchymal protein marker vimentin was significantly downregulated following CILP overexpression, suggesting that CILP could participate in migration through epithelial-mesenchymal transition (EMT). A comparison of CILP expression using immunohistochemistry in BC and BCBM showed that CILP was significantly downregulated in BCBM. In addition, gene set variation analysis (GSVA) revealed that CILP was associated with the T-cell receptor signaling pathway in BCBM and BC, indicating that CILP may be involved in BCBM through immune effects. BCBM showed lower immune infiltration than BC. Moreover, CILP expression was positively correlated with HLA-II, T helper cells (CD4⁺ T cells), and Type II IFN Response in BCBM. Collectively, our study indicates that CILP is associated with immune infiltration and may be a putative gene involved in BCBM. CILP offers new insights into the pathogenesis of BCBM, which will facilitate the development of novel targets for BCBM patients.

Feed-forward loops between metastatic cancer cells and their microenvironment-the stage of escalation

Breast cancer is the most frequent cancer among women, and metastases in distant organs are the leading cause of the cancer-related deaths. While survival of early-stage breast cancer patients has increased dramatically, the 5-year survival rate of metastatic patients has barely improved in the last 20 years. Metastases can arise up to decades after primary tumor resection, hinting at microenvironmental factors influencing the sudden outgrowth of disseminated tumor cells (DTCs). This review summarizes how the environment of the most common metastatic sites (lung, liver, bone, brain) is influenced by the primary tumor and by the varying dormancy of DTCs, with a special focus on how established metastases persist and grow in distant organs due to feed-forward loops (FFLs). We discuss in detail the importance of FFL of cancer cells with their microenvironment including the secretome, interaction with specialized tissue-specific cells, nutrients/metabolites, and that novel therapies should target not only the cancer cells but also the tumor microenvironment, which are thick as thieves.

Metabolomics and EMT Markers of Breast Cancer: A Crosstalk and Future Perspective

Cancer cells undergo transient EMT and MET phenomena or vice versa, along with the parallel interplay of various markers, often correlated as the determining factor in decoding metabolic profiling of breast cancers. Moreover, various cancer signaling pathways and metabolic changes occurring in breast cancer cells modulate the expression of such markers to varying extents. The existing research completed so far considers the expression of such markers as determinants regulating the invasiveness and survival of breast cancer cells. Therefore, this manuscript is crosstalk among the expression levels of such markers and their correlation in regulating the aggressiveness and invasiveness of breast cancer. We also attempted to cover the possible EMT-based metabolic targets to retard migration and invasion of breast cancer.

Leptin Silencing Attenuates Lipid Accumulation through Sterol Regulatory Element-Binding Protein 1 Inhibition in Nasopharyngeal Carcinoma

Leptin is a crucial regulator of metabolism and energy homeostasis in mammals. Many studies have investigated the impacts of leptin on human cancers, such as proliferation and metastasis. However, the mechanisms underlying leptin-mediated regulation of lipid metabolism in nasopharyngeal carcinoma (NPC) remain incompletely understood. In the current study, leptin downregulation ameliorated lipid accumulation, triglyceride, and cholesterol levels. Mechanistically, diminished leptin by siRNA not only inhibited sterol regulatory element-binding protein 1 (SREBP1), a master regulator of lipid metabolism, at the mRNA and protein levels, but also reduced SREBP1 downstream target expressions, such as fatty acid synthase (FASN) and stearoyl-CoA desaturase-1 (SCD1), in NPC cells. In addition, leptin expression could modulate the promoter activity of SREBP1. We also found that pharmacological inhibition of poly-ADP ribose polymerase-γ (PPAR-γ) resulted in increased SREBP1 expression in leptin-depleted NPC cells. Functionally, SREBP1 overexpression overcame the effects of leptin-silencing attenuated triglyceride level, cholesterol level and cell survival in NPC cells. Taken together, our results demonstrate that leptin is an important regulator of lipid metabolism in NPC cells and might could be a potential therapeutic target for treatment of NPC patients.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

Al-MPS Obstructs EMT in Breast Cancer by Inhibiting Lipid Metabolism via miR-215-5p/SREBP1

Alkali-extractable mycelial polysaccharide (Al-MPS) is a natural macromolecular polymer that has shown anti-hyperlipidemic and antitumor abilities. This study investigates the mechanism by which Al-MPS inhibits lipid metabolism and epithelial-mesenchymal transition (EMT) in breast cancer (BC). BC cells (MCF-7 and MDA-MB-231) were transfected and/or treated with Al-MPS. CCK-8, Transwell, and scratch assays were used to evaluate the tumorigenic behaviors of BC cells. The expression levels of SREBP1, E-cadherin, N-cadherin, Snail, vimentin, FASN, ACLY, and ACECS1 in BC cells were detected by Western blotting. Dual-luciferase reporter and RNA pull-down assays were performed to verify the binding between miR-215-5p and SREBP1 mRNA. Nude mice were injected with MDA-MB-231 cells and treated with Al-MPS. The changes in tumor volume and protein expression were monitored. miR-215-5p was downregulated and SREBP1 was upregulated in BC. Al-MPS increased miR-215-5p expression and inhibited SREBP1 expression, lipid metabolism, and EMT in BC. Inhibition of miR-215-5p or overexpression of SREBP1 promoted the tumorigenic behaviors of BC cells by stimulating lipid metabolism and counteracted the antitumor effect of Al-MPS. SREBP1 was a downstream target of miR-215-5p. In conclusion, Al-MPS inhibits lipid metabolism and EMT in BC via the miR-215-5p/SREBP1 axis. This study supports the application of polysaccharides in cancer treatment and the molecules regulated by Al-MPS may be used as biomarkers or therapeutic targets for BC.

Disruption of miR-18a Alters Proliferation, Photoreceptor Replacement Kinetics, Inflammatory Signaling, and Microglia/Macrophage Numbers During Retinal Regeneration in Zebrafish

In mammals, photoreceptor loss causes permanent blindness, but in zebrafish (Danio rerio), photoreceptor loss reprograms Müller glia to function as stem cells, producing progenitors that regenerate photoreceptors. MicroRNAs (miRNAs) regulate CNS neurogenesis, but the roles of miRNAs in injury-induced neuronal regeneration are largely unknown. In the embryonic zebrafish retina, miR-18a regulates photoreceptor differentiation. The purpose of the current study was to determine, in zebrafish, the function of miR-18a during injury-induced photoreceptor regeneration. RT-qPCR, in situ hybridization, and immunohistochemistry showed that miR-18a expression increases throughout the retina between 1 and 5 days post-injury (dpi). To test miR-18a function during photoreceptor regeneration, we used homozygous miR-18a mutants (miR-18ami5012), and knocked down miR-18a with morpholino oligonucleotides. During photoreceptor regeneration, miR-18ami5012 retinas have fewer mature photoreceptors than WT at 7 and 10 dpi, but there is no difference at 14 dpi, indicating that photoreceptor regeneration is delayed. Labeling dividing cells with 5-bromo-2'-deoxyuridine (BrdU) showed that at 7 and 10 dpi, there are excess dividing progenitors in both mutants and morphants, indicating that miR-18a negatively regulates injury-induced proliferation. Tracing 5-ethynyl-2'-deoxyuridine (EdU) and BrdU-labeled cells showed that in miR-18ami5012 retinas excess progenitors migrate to other retinal layers in addition to the photoreceptor layer. Inflammation is critical for photoreceptor regeneration, and RT-qPCR showed that in miR-18ami5012 retinas, inflammatory gene expression and microglia activation are prolonged. Suppressing inflammation with dexamethasone rescues the miR-18ami5012 phenotype. Together, these data show that in the injured zebrafish retina, disruption of miR-18a alters proliferation, inflammation, the microglia/macrophage response, and the timing of photoreceptor regeneration.

SUMOylation and NEDDylation in Primary and Metastatic Cancers to Bone

Post-translational modifications comprise series of enzymatically-driven chemical modifications, virtually involving the entire cell proteome, that affect the fate of a target protein and, in turn, cell activity. Different classes of modifications can be established ranging from phosphorylation, glycosylation, ubiquitination, acetylation, methylation, lipidation and their inverse reactions. Among these, SUMOylation and NEDDylation are ubiquitin-like multi-enzymatic processes that determine the bound of SUMOs and NEDD8 labels, respectively, on defined amino acidic residues of a specific protein and regulate protein function. As fate-determinants of several effectors and mediators, SUMOylation and NEDDylation play relevant roles in many aspects of tumor cell biology. Bone represents a preferential site of metastasis for solid tumors (e.g., breast and prostate cancers) and the primary site of primitive tumors (e.g., osteosarcoma, chondrosarcoma). Deregulation of SUMOylation and NEDDylation affects different aspects of neoplastic transformation and evolution such as epithelial-mesenchymal transition, adaptation to hypoxia, expression and action of tumor suppressors and oncogenic mediators, and drug resistance. Thereby, they represent potential therapeutic targets. This narrative review aims at describing the involvement and regulation of SUMOylation and NEDDylation in tumor biology, with a specific focus on primary and secondary bone tumors, and to summarize and highlight their potentiality in diagnostics and therapeutic strategies.

Dynamic miRNA Landscape Links Mammary Gland Development to the Regulation of Milk Protein Expression in Mice

Simple Summary

Milk synthesis is vital for maintaining the normal growth of newborn animals. Abnormal mammary gland development leads to a decrease in female productivity and the overall productivity of animal husbandry. This study characterized the dynamic miRNA expression profile during the process of mammary gland development, and identified a novel miRNA regulating expression of β-casein—an important milk protein. The results are valuable for studying mammary gland development, increasing milk production, improving the survival rate of pups, and promoting the development of animal husbandry.

Abstract

Mammary gland morphology varies considerably between pregnancy and lactation status, e.g., virgin to pregnant and lactation to weaning. Throughout these critical developmental phases, the mammary glands undergo remodeling to accommodate changes in milk production capacity, which is positively correlated with milk protein expression. The purpose of this study was to investigate the microRNA (miRNA) expression profiles in female ICR mice’s mammary glands at the virgin stage (V), day 16 of pregnancy (P16d), day 12 of lactation (L12d), day 1 of forced weaning (FW1d), and day 3 of forced weaning (FW3d), and to identify the miRNAs regulating milk protein gene expression. During the five stages of testing, 852 known miRNAs and 179 novel miRNAs were identified in the mammary glands. Based on their expression patterns, the identified miRNAs were grouped into 12 clusters. The expression pattern of cluster 1 miRNAs was opposite to that of milk protein genes in mammary glands in all five different stages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the predicted target genes of cluster 1 miRNAs were related to murine mammary gland development and lactation. Furthermore, fluorescence in situ hybridization (FISH) analysis revealed that the novel-mmu-miR424-5p, which belongs to the cluster 1 miRNAs, was expressed in murine mammary epithelial cells. The dual-luciferase reporter assay revealed that an important milk protein gene—β-casein (CSN2)—was regarded as one of the likely targets for the novel-mmu-miR424-5p. This study analyzed the expression patterns of miRNAs in murine mammary glands throughout five critical developmental stages, and discovered a novel miRNA involved in regulating the expression of CSN2. These findings contribute to an enhanced understanding of the developmental biology of mammary glands, providing guidelines for increasing lactation efficiency and milk quality.