R-spondin 2-LGR4 system regulates growth, migration and invasion, epithelial-mesenchymal transition and stem-like properties of tongue squamous cell carcinoma via Wnt/β-catenin signaling

Knockdown of LRP5 Promotes Proliferation and Invasion of Tongue Squamous Cell Carcinoma through Compensatory Activation of Akt Signaling

The role of LRP5, a critical receptor in the Wnt signaling pathway, remains unexplored in tongue squamous cell carcinoma (TSCC). This study investigates the impact of LRP5 knockdown on the biological behaviors of TSCC cell lines both in vitro and in vivo. Our findings indicate that LRP5 knockdown significantly enhances cell proliferation, migration, and invasion in CAL27 and SCC25 cell lines. RNA-seq analysis reveals compensatory activation of the Akt pathway, with 119 genes significantly upregulated post-LRP5 knockdown. Elevated MMP1 expression suggests its potential involvement in TSCC progression. Western blot analysis demonstrates increased Akt phosphorylation, upregulated proliferation-related PCNA, and downregulated apoptosis-related caspase-3 after LRP5 knockdown. Down-regulation of E-cadherin and β-Catenin, proteins associated with cell adhesion and invasion, further elucidates the molecular mechanism underlying increased cell migration and invasion. Our study concludes that compensatory Akt pathway activation is essential for the LRP5 knockdown-induced migration and proliferation of CAL27 and SCC25 cells. These results highlight LRP5 as a potential therapeutic target for TSCC. Simultaneous inhibition of Wnt and Akt signaling emerges as a promising approach for TSCC treatment.

Rspo2-LGR4 exacerbates hepatocellular carcinoma progression via activation of Wnt/β-catenin signaling pathway

BACKGROUND

The leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays an important role in stem cell differentiation, organ development and cancer. Whether LGR4 affects the progression of hepatocellular carcinoma (HCC) remains unknown. This study aimed to reveal the role of LGR4 in HCC.

METHODS

Clinical samples of HCC were collected to assess the expression of LGR4 and its correlation with patients' clinical characteristics. The expression level of LGR4 in HCC cells was altered by pharmacological and genetic methods, and the role of LGR4 in HCC progression was analyzed by in vivo and in vitro assays. HCC was induced by diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) in wild-type and LGR4 deficient mice, the effect of LGR4 on HCC was examined by histopathological evaluation and biochemical assays.

RESULTS

LGR4 expression was up-regulated in HCC samples, and its expression level was positively correlated with tumor size, microvascular invasion (MVI), TNM stage and pathological differentiation grade of HCC patients. In the mouse HCC model induced by DEN+CCl4, knockdown of LGR4 effectively inhibited the progression of HCC. Silencing of LGR4 inhibited the proliferation, migration, invasion, stem cell-like properties and Warburg effect of HCC cells. These phenotypes were promoted by R-spondin2 (Rspo2), an endogenous ligand for LGR4. Rspo2 markedly increased the nuclear translocation of β-catenin, whereas IWR-1, an inhibitor of Wnt/β-catenin signaling, reversed its effect. Deficiency of LGR4 significantly reduced the nuclear translocation of β-catenin and the expression of its downstream target genes cyclinD1 and c-Myc.

CONCLUSIONS

LGR4 promotes HCC progression via Wnt/β-catenin signaling pathway.

The biological functions and related signaling pathways of SPON2

Spondin-2 (SPON2), also referred to as M-spondin or DIL-1, is a member of the extracellular matrix protein family known as Mindin-F-spondin (FS). SPON2 can be used as a broad-spectrum tumor marker for more than a dozen tumors, mainly prostate cancer. Meanwhile, SPON2 is also a potential biomarker for the diagnosis of certain non-tumor diseases. Additionally, SPON2 plays a pivotal role in regulating tumor metastasis and progression. In normal tissues, SPON2 has a variety of biological functions represented by promoting growth and development and cell proliferation. This paper presents a comprehensive overview of the regulatory mechanisms, diagnostic potential as a broad-spectrum biomarker, diverse biological functions, involvement in various signaling pathways, and clinical applications of SPON2.

R-spondin family biology and emerging linkages to cancer

The R-spondin protein family comprises four members (RSPO1-4), which are agonists of the canonical Wnt/β-catenin pathway. Emerging evidence revealed that RSPOs should not only be viewed as agonists of the Wnt/β-catenin pathway but also as regulators for tumor development and progression. Aberrant expression of RSPOs is related to tumorigenesis and tumor development in multiple cancers and their expression of RSPOs has also been correlated with anticancer immune cell signatures. More importantly, the role of RSPOs as potential target therapies and their implication in cancer progressions has been studied in the preclinical and clinical settings. These findings highlight the possible therapeutic value of RSPOs in cancer medicine. However, the expression pattern, effects, and mechanisms of RSPO proteins in cancer remain elusive. Investigating the many roles of RSPOs is likely to expand and improve our understanding of the oncogenic mechanisms mediated by RSPOs. Here, we reviewed the recent advances in the functions and underlying molecular mechanisms of RSPOs in tumor development, cancer microenvironment regulation, and immunity, and discussed the therapeutic potential of targeting RSPOs for cancer treatment. In addition, we also explored the biological feature and clinical relevance of RSPOs in cancer mutagenesis, transcriptional regulation, and immune correlation by bioinformatics analysis.KEY MESSAGESAberrant expressions of RSPOs are detected in various human malignancies and are always correlated with oncogenesis.Although extensive studies of RSPOs have been conducted, their precise molecular mechanism remains poorly understood.Bioinformatic analysis revealed that RSPOs may play a part in the development of the immune composition of the tumor microenvironment.

Rspo2 exacerbates rheumatoid arthritis by targeting aggressive phenotype of fibroblast-like synoviocytes and disrupting chondrocyte homeostasis via Wnt/β-catenin pathway

BACKGROUND

The aggressive phenotype of fibroblast-like synoviocytes (FLS) has been identified as a contributing factor to the exacerbation of rheumatoid arthritis (RA) through the promotion of synovitis and cartilage damage. Regrettably, there is currently no effective therapeutic intervention available to address this issue. Recent research has shed light on the crucial regulatory role of R-spondin-2 (Rspo2) in cellular proliferation, cartilage degradation, and tumorigenesis. However, the specific impact of Rspo2 on RA remains poorly understood. We aim to investigate the function and mechanism of Rspo2 in regulating the aggressive phenotype of FLS and maintaining chondrocyte homeostasis in the context of RA.

METHODS

The expression of Rspo2 in knee joint synovium and cartilage were detected in RA mice with antigen-induced arthritis (AIA) and RA patients. Recombinant mouse Rspo2 (rmRspo2), Rspo2 neutralizing antibody (Rspo2-NAb), and recombinant mouse DKK1 (rmDKK1, a potent inhibitor of Wnt signaling pathway) were used to explore the role and mechanism of Rspo2 in the progression of RA, specifically in relation to the aggressive phenotype of FLS and chondrocyte homeostasis, both in vivo and in vitro.

RESULTS

We indicated that Rspo2 expression was upregulated both in synovium and articular cartilage as RA progressed in RA mice and RA patients. Increased Rspo2 upregulated the expression of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), as the ligand for Rspo2, and β-catenin in FLS and chondrocytes. Subsequent investigations revealed that intra-articular administration of rmRspo2 caused striking progressive synovitis and articular cartilage destruction to exacerbate RA progress in mice. Conversely, neutralization of Rspo2 or inhibition of the Wnt/β-catenin pathway effectively alleviated experimental RA development. Moreover, Rspo2 facilitated FLS aggressive phenotype and disrupted chondrocyte homeostasis primarily through activating Wnt/β-catenin pathway, which were effectively alleviated by Rspo2-NAb or rmDKK1.

CONCLUSIONS

Our data confirmed a critical role of Rspo2 in enhancing the aggressive phenotype of FLS and disrupting chondrocyte homeostasis through the Wnt/β-catenin pathway in the context of RA. Furthermore, the results indicated that intra-articular administration of Rspo2 neutralizing antibody or recombinant DKK1 might represent a promising therapeutic strategy for the treatment of RA.

LGR4 promotes tumorigenesis by activating TGF-β1/Smad signaling pathway in multiple myeloma

Multiple myeloma (MM) is a common hematologic malignancy that remains incurable. Although accumulating evidence suggests that the leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) plays a biological function in a variety of cancers, its biological function and molecular mechanisms in MM are unclear. In the present study, we found that LGR4 was significantly upregulated in MM tissues and cells. In vitro and in vivo experiments showed that knockdown of LGR4 significantly inhibited proliferation of MM cells, promoted apoptosis and arrested cell cycle in G1. Overexpression showed the opposite effect. Mechanistic studies revealed that LGR4 could interact with TGF-β1 and regulate TGF-β1 expression, thereby activating the TGF-β1/Smad signaling pathway and promoting MM progression. LGR4 may be a potential new target for MM diagnosis and treatment.

Expression and effect of heterogeneous nuclear ribonucleoprotein A2/B1 in tongue squamous cell carcinoma

OBJECTIVES

Tongue squamous cell carcinoma (TSCC) is a common cancer in the oral and maxillofacial region, which seriously endangers people's life and health.Heterogeneous nuclear ribonucleoprotein A2/B1(hnRNP A2/B1) is an RNA-binding protein that regulates the expression of a variety of genes and participates in the occurrence and development of a variety of cancers. This study aims to investigate the role of hnRNP A2/B1 in TSCC progression.

METHODS

The differential expression of hnRNP A2/B1 in oral squamous cell carcinoma (OSCC) and normal oral mucosa cells and tissues was analyzed based on the gene expression profiles of GSE146483 and GSE85195 in the Gene Expression Omnibus (GEO) database. The correlation between hnRNP A2/B1 expression and disease-free survival of TSCC patients was analyzed based on TSCC related chip of GSE4676. TSCC cancer and paracancerous tissue samples of 30 patients were collected in Hunan Cancer Hospital from July to December 2021. Real-time RT-PCR and Western blotting were used to verify the mRNA and protein expression of hnRNP A2/B1 in TSCC patients'samples, respectively. Human TSCC Tca-8113 cells were transfected with hnRNP A2/B1 empty vector (a sh-NC group), knockdown plasmid (a sh-hnRNP A2/B1 group), empty vector overexpression plasmid (an OE-NC group) and overexpression plasmid (an OE-hnRNP A2/B1 group), respectively. The knockdown or overexpression efficiency of hnRNP A2/B1 was detected by Western blotting. The proliferation activity of Tca-8113 cells was detected by cell counting kit-8 (CCK-8), and the apoptosis rate of Tca-8113 cells was detected by flow cytometry.

RESULTS

Based on the analysis of OSCC-related chips of GSE146483 and GSE85195 in the GEO database, it was found that hnRNP A2/B1 was differentially expressed in the OSCC and normal oral mucosa cells and tissues (all P<0.01). Meanwhile, the analysis of TSCC related chip GSE4676 confirmed that the expression of hnRNP A2/B1 was negatively correlated with the disease-free survival of TSCC patients (P=0.006). The results of real-time RT-PCR and Western blotting showed that the relative expression levels of hnRNP A2/B1 mRNA and protein in TSCC tissues were significantly up-regulated compared with those in adjacent tissues (all P<0.01). The results of Western blotting showed that the expression level of hnRNP A2/B1 in Tca-8113 cells was significantly inhibited or promoted after knockdown or overexpression of hnRNP A2/B1 (all P<0.01). The results of CCK-8 and flow cytometry showed that inhibition of hnRNP A2/B1 expression in Tca-8113 cells reduced cell proliferation activity (P<0.05) and increased cell apoptic rate (P<0.01). Overexpression of hnRNP A2/B1 in Tca-8113 cells significantly increased cell proliferation (P<0.05) and decreased cell apoptosis (P<0.01).

CONCLUSIONS

HnRNP A2/B1 is a key factor regulating the proliferation and apoptosis of TSCC cells. Inhibition of hnRNP A2/B1 expression can reduce the proliferation activity of TSCC cells and promote the apoptosis of TSCC cells.

Effect of LGR4/EGFR signaling on cell growth and cancer stem cell-like characteristics in liver cancer

PURPOSE

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Leucine-rich repeat containing G-protein-coupled receptors 4 (LGR4) participates in tumor progression, invasion, and metastasis. Our study aimed to investigate the effect of LGR4 with epidermal growth factor receptor (EGFR) in HCC cells.

METHODS

We employed Hep3B and Huh7 cells to conduct our research. Comprehensive biological activities were characterized by CCK8 and transwell assay. Molecular biology techniques were used to determine the expression of proteins. Hep3B was employed to conduct subcutaneous tumor in mice. The tumor growth and the expression levels of proteins were assessed.

RESULTS

LGR4 overexpression could promote the cells proliferation, migration, and invasion ability, while siLGR4 and siEGFR could inhibit cells biological activities. In addition, LGR4 overexpression promoted the expression levels of RSPO2, β-catenin, EGFR and cancer stem cells (CSCs) markers, whereas silence of LGR4 or EGFR could diminish the expression levels of β-catenin and CSCs markers. Furthermore, knockdown of LGR4 or EGFR also inhibited tumor growth and reduced the expression levels of RSPO2, CD133, CD44, Nanog, β-catenin in vivo.

CONCLUSION

Our data suggest that LGR4 /EGFR signaling in HCC leads to induce tumor growth, which then contributes to stem cell characteristics. It maybe a new perspective for the targeted therapy of HCC treatment.

Immunity-related long noncoding RNA WDFY3-AS2 inhibited cell proliferation and metastasis through Wnt/β-catenin signaling in oral squamous cell carcinoma

OBJECTIVE

Long noncoding RNA WDFY3-AS2 has been shown to play dual roles in the modulation of cancer progression. This study aimed at clarifying the biological role of WDFY3-AS2 as well as the association between WDFY3-AS2 expression, β-catenin expression, and OSCC immunity in oral squamous cell carcinoma (OSCC).

DESIGN

Bioinformatics analyses, CCK8, EdU, wound healing, transwell, RT-qPCR, western blot, immunofluorescence, in situ hybridization, and immunohistochemistry assays were adopted for exploring the role of WDFY3-AS2 in OSCC.

RESULTS

Bioinformatics analyses showed that WDFY3-AS2 conferred a poor prognosis for OSCC patients. Further analyses identified WDFY3-AS2 as an independent prognostic indicator for OSCC. Moreover, silencing WDFY3-AS2 inhibits OSCC cell proliferation, migration and invasion. Gene set enrichment analysis indicated that WDFY3-AS2 participated in the regulation of Wnt signaling. In addition, WDFY3-AS2 expression was positively associated with β-catenin mRNA levels, the key component of Wnt signaling. Interestingly, WDFY3-AS2 knockdown inhibited β-catenin expression and nuclear translocation, thus suppressing OSCC progression through Wnt signaling. Furthermore, WDFY3-AS2 expression correlated with an immunosuppressive phenotype in the tumor immune microenvironment. In situ hybridization and immunohistochemistry verified that WDFY3-AS2 was positively associated with total and nuclear β-catenin protein levels and negatively associated with CD4 expression.

CONCLUSIONS

This study demonstrates that the immunity-associated WDFY3-AS2 augments OSCC proliferation and metastasis through Wnt/β-catenin signaling and may serve as a novel treatment target and a new prognostic factor for OSCC.

LINC00669 promotes lung adenocarcinoma growth by stimulating the Wnt/β-catenin signaling pathway

Lung cancer poses severe threats to human health. It is indispensable to discover more druggable molecular targets. We identified a novel dysregulated long non-coding RNA (lncRNA), LINC00669, in lung adenocarcinoma (LUAD) by analyzing the TCGA and GEO databases. Pan-cancer analysis indicated significantly upregulated LINC00669 across 33 cancer types. GSEA revealed a tight association of LINC00669 with the cell cycle. We next attempted to improve the prognostic accuracy of this lncRNA by establishing a risk signature in reliance on cell cycle genes associated with LINC00669. The resulting risk score combined with LINC00669 and stage showed an AUC of 0.746. The risk score significantly stratified LUAD patients into low- and high-risk subgroups, independently predicting prognosis. Its performance was verified by nomogram (C-index = 0.736) and decision curve analysis. Gene set variation analysis disclosed the two groups' molecular characteristics. We also evaluated the tumor immune microenvironment by dissecting 28 infiltrated immune cells, 47 immune checkpoint gene expressions, and immunophenoscore within the two subgroups. Furthermore, the risk signature could predict sensitivity to immune checkpoint inhibitors and other anticancer therapies. Eventually, in vitro and in vivo experiments were conducted to validate LINC00669's function using qRT-PCR, CCK8, flow cytometry, western blot, and immunofluorescence staining. The gain- and loss-of-function study substantiated LINC00669's oncogenic effects, which stimulated non-small cell lung cancer cell proliferation but reduced apoptosis via activating the Wnt/β-catenin pathway. Its oncogenic potentials were validated in the xenograft mouse model. Overall, we identified a novel oncogenic large intergenic non-coding RNA (lincRNA), LINC00669. The resulting signature may facilitate predicting prognosis and therapy responses in LUAD.

Carboxylesterase 2 induces mitochondrial dysfunction via disrupting lipid homeostasis in oral squamous cell carcinoma

OBJECTIVE

Oral squamous cell carcinoma (OSCC) is characterized by high recurrence and metastasis and places a heavy burden on societies worldwide. Cancer cells thrive in a changing microenvironment by reprogramming lipidomic metabolic processes to provide nutrients and energy, activate oncogenic signaling pathways, and manage redox homeostasis to avoid lipotoxicity. The mechanism by which OSCC cells maintain lipid homeostasis during malignant progression is unclear.

METHODS

The altered expression of fatty acid (FA) metabolism genes in OSCC, compared with that in normal tissues, and in OSCC patients with or without recurrence or metastasis were determined using public data from the TCGA and GEO databases. Immunohistochemistry was performed to examine the carboxylesterase 2 (CES2) protein level in our own cohort. CCK-8 and Transwell assays and an in vivo xenograft model were used to evaluate the biological functions of CES2. Mass spectrometry and RNA sequencing were performed to determine the lipidome and transcriptome alterations induced by CES2. Mitochondrial mass, mtDNA content, mitochondrial membrane potential, ROS levels, and oxygen consumption and apoptosis rates were evaluated to determine the effects of CES2 on mitochondrial function in OSCC.

RESULTS

CES2 was downregulated in OSCC patients, especially those with recurrence or metastasis. CES2^high OSCC patients showed better overall survival than CES2^low OSCC patients. Restoring CES2 expression reduced OSCC cell viability and suppressed their migration and invasion in vitro, and it inhibited OSCC tumor growth in vivo. CES2 reprogrammed lipid metabolism in OSCC cells by hydrolyzing neutral lipid diacylglycerols (DGs) to release free fatty acids and reduce the membrane structure lipid phospholipids (PLs) synthesis. Free FAs were converted to acyl-carnitines (CARs) and transferred to mitochondria for oxidation, which induced reactive oxygen species (ROS) accumulation, mitochondrial damage, and apoptosis activation. Furthermore, the reduction in signaling lipids, e.g., DGs, PLs and substrates, suppressed PI3K/AKT/MYC signaling pathways. Restoring MYC rescued the diminished cell viability, suppressed migratory and invasive abilities, damaged mitochondria and reduced apoptosis rate induced by CES2.

CONCLUSIONS

We demonstrated that CES2 downregulation plays an important role in OSCC by maintaining lipid homeostasis and reducing lipotoxicity during tumor progression and may provide a potential therapeutic target for OSCC.

Hsa_circ_0003945 promotes progression of hepatocellular carcinoma by mediating miR-34c-5p/LGR4/β-catenin axis activity

Accumulating evidence suggests that circular RNAs (circRNAs) play essential roles in regulating cancer progression, but many circRNAs in hepatocellular carcinoma (HCC) remain unknown. Dysregulated circRNAs in HCC were identified through bioinformatics analysis of Gene Expression Omnibus data sets. Quantitative real‐time PCR (qRT‐PCR), Sanger sequencing, RNase R digestion and actinomycin D treatment were conducted to confirm the characterization of circRNAs. CCK‐8, wound‐healing and Transwell assays were performed to assess the functional roles of Hsa_circ_0003945 (Circ_0003945) in HCC cell lines. Subcellular fractionation and fluorescence in situ hybridization (FISH) were performed to locate Circ_0003945 in HCC cells. Dual‐luciferase reporter assay was executed to verify the binding of Circ_0003945 to microRNAs (miRNAs) or the miRNAs to their target genes. In this study, we found that Circ_0003945 was upregulated in HCC tissue, and higher Circ_0003945 expression was positively correlated with tumour size and tumour stage. Furthermore, high plasma levels of circulating Circ_0003945 were confirmed in HCC patients compared with those in non‐HCC groups. The functional experiments revealed that overexpression or knockdown of Circ_0003945 promoted or attenuated tumour growth and migration, respectively. Mechanistically, Circ_0003945 might exert as a miR‐34c‐5p sponge to upregulate the expression of leucine‐rich repeat‐containing G protein‐coupled receptor 4 (LGR4), activating the β‐catenin pathway, and finally facilitating HCC progression. Additionally, a β‐catenin activator could reverse the effect of Circ_0003945 knockdown. In conclusion, Circ_0003945 exerts a tumour‐promoting role in HCC cells by regulating the miR‐34c‐5p/LGR4/β‐catenin axis, which may be a potential target for HCC therapy.

Emerging Roles for LGR4 in Organ Development, Energy Metabolism and Carcinogenesis

The leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) belonging to G protein-coupled receptors (GPCRs) family, had various regulatory roles at multiple cellular types and numerous targeting sites, and aberrant LGR4 signaling played crucial roles in diseases and carcinogenesis. On the basis of these facts, LGR4 may become an appealing therapeutic target for the treatment of diseases and tumors. However, a comprehensive investigation of its functions and applications was still lacking. Hence, this paper provided an overview of the molecular characteristics and signaling mechanisms of LGR4, its involvement in multiple organ development and participation in the modulation of immunology related diseases, metabolic diseases, and oxidative stress damage along with cancer progression. Given that GPCRs accounted for almost a third of current clinical drug targets, the in-depth understanding of the sophisticated connections of LGR4 and its ligands would not only enrich their regulatory networks, but also shed new light on designing novel molecular targeted drugs and small molecule blockers for revolutionizing the treatment of various diseases and tumors.

LGR4, a G Protein-Coupled Receptor With a Systemic Role: From Development to Metabolic Regulation

Leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4/GPR48), a member of the GPCR (G protein-coupled receptors) superfamily, subfamily B, is a common intestinal crypt stem cell marker. It binds R-spondins/Norrin as classical ligands and plays a crucial role in Wnt signaling potentiation. Interaction between LGR4 and R-spondins initiates many Wnt-driven developmental processes, e.g., kidney, eye, or reproductive tract formation, as well as intestinal crypt (Paneth) stem cell pool maintenance. Besides the well-described role of LGR4 in development, several novel functions of this receptor have recently been discovered. In this context, LGR4 was indicated to participate in TGFβ and NFκB signaling regulation in hematopoietic precursors and intestinal cells, respectively, and found to be a new, alternative receptor for RANKL (Receptor Activator of NF kappa B Ligand) in bone cells. LGR4 inhibits the process of osteoclast differentiation, by antagonizing the interaction between RANK (Receptor Activator of NF kappa B) and its ligand-RANKL. It is also known to trigger anti-inflammatory responses in different tissues (liver, intestine, cardiac cells, and skin), serve as a sensor of the circadian clock in the liver, regulate adipogenesis and energy expenditure in adipose tissue and skeletal muscles, respectively. The extracellular domain of LGR4 (LGR4-ECD) has emerged as a potential new therapeutic for osteoporosis and cancer. LGR4 integrates different signaling pathways and regulates various cellular processes vital for maintaining whole-body homeostasis. Yet, the role of LGR4 in many cell types (e.g. pancreatic beta cells) and diseases (e.g., diabetes) remains to be elucidated. Considering the broad spectrum of LGR4 actions, this review aims to discuss both canonical and novel roles of LGR4, with emphasis on emerging research directions focused on this receptor.

A Review of Prostate Organogenesis and a Role for iPSC-Derived Prostate Organoids to Study Prostate Development and Disease

The prostate is vulnerable to two major age-associated diseases, cancer and benign enlargement, which account for significant morbidity and mortality for men across the globe. Prostate cancer is the most common cancer reported in men, with over 1.2 million new cases diagnosed and 350,000 deaths recorded annually worldwide. Benign prostatic hyperplasia (BPH), characterised by the continuous enlargement of the adult prostate, symptomatically afflicts around 50% of men worldwide. A better understanding of the biological processes underpinning these diseases is needed to generate new treatment approaches. Developmental studies of the prostate have shed some light on the processes essential for prostate organogenesis, with many of these up- or downregulated genes expressions also observed in prostate cancer and/or BPH progression. These insights into human disease have been inferred through comparative biological studies relying primarily on rodent models. However, directly observing mechanisms of human prostate development has been more challenging due to limitations in accessing human foetal material. Induced pluripotent stem cells (iPSCs) could provide a suitable alternative as they can mimic embryonic cells, and iPSC-derived prostate organoids present a significant opportunity to study early human prostate developmental processes. In this review, we discuss the current understanding of prostate development and its relevance to prostate-associated diseases. Additionally, we detail the potential of iPSC-derived prostate organoids for studying human prostate development and disease.

RSPO2/RANKL-LGR4 signaling regulates osteoclastic pre-metastatic niche formation and bone metastasis

Therapeutics targeting osteoclasts are commonly used treatments for bone metastasis; however, whether and how osteoclasts regulate pre-metastatic niche and bone tropism is largely unknown. In this study, we report that osteoclast precursors (OPs) can function as a pre-metastatic niche component that facilitates breast cancer (BCa) bone metastasis at early stages. At the molecular level, unbiased GPCR ligand/agonist screening in BCa cells suggested that R-spondin 2 (RSPO2) and RANKL, through interacting with their receptor LGR4, promoted osteoclastic pre-metastatic niche formation and enhanced BCa bone metastasis. This was achieved by RSPO2/RANKL-LGR4 signal modulating WNT inhibitor DKK1 through Gαq and β-catenin signaling. DKK1 directly facilitated OP recruitment through suppressing its receptor low-density lipoprotein-related receptors 5 (LRP5) but not LRP6, upregulating Rnasek expression via inhibiting canonical WNT signaling. In clinical samples, RSPO2, LGR4 and DKK1 expression showed positive correlation with BCa bone metastasis. Furthermore, soluble LGR4 extracellular domain (ECD) protein, acting as a decoy receptor for RSPO2 and RANKL, significantly alleviated bone metastasis and osteolytic lesions in mouse bone metastasis model. These findings provide unique insights into the functional role of OPs as key components of pre-metastatic niche for BCa bone metastasis, indicate RSPO2/RANKL-LGR4 signaling as a promising target for inhibiting BCa bone metastasis.

Cancer and diabetes: the interlinking metabolic pathways and repurposing actions of antidiabetic drugs

Cancers are regarded as one of the main causes of death and result in high health burden worldwide. The management of cancer include chemotherapy, surgery and radiotherapy. The chemotherapy, which involves the use of chemical agents with cytotoxic actions is utilised as a single treatment or combined treatment. However, these managements of cancer such as chemotherapy poses some setbacks such as cytotoxicity on normal cells and the problem of anticancer drug resistance. Therefore, the use of other therapeutic agents such as antidiabetic drugs is one of the alternative interventions used in addressing some of the limitations in the use of anticancer agents. Antidiabetic drugs such as sulfonylureas, biguanides and thiazolidinediones showed beneficial and repurposing actions in the management of cancer, thus, the activities of these drugs against cancer is attributed to some of the metabolic links between the two disorders and these includes hyperglycaemia, hyperinsulinemia, inflammation, and oxidative stress as well as obesity. Furthermore, some studies showed that the use of antidiabetic drugs could serve as risk factors for the development of cancerous cells particularly pancreatic cancer. However, the beneficial role of these chemical agents overweighs their detrimental actions in cancer management. Hence, the present review indicates the metabolic links between cancer and diabetes and the mechanistic actions of antidiabetic drugs in the management of cancers.

Role of TCF-1 in differentiation, exhaustion, and memory of CD8+ T cells: A review

T cell factor-1 (TCF-1) (encoded by the TCF7 gene) is a transcription factor that plays important role during the T cell development and differentiation for T cell to exercise its functions including producing memory T cells. Not only TCF-1 can modulate the T cell development but also exerts various effects on the differentiation and function of mature CD8⁺ T cells. In addition, it drives the production and maintenance of the immune response of CD8⁺ T cells after PD-1 checkpoint blockade therapy. TCF-1 can serve as a potential target of immunotherapy and may provide promising novel treatment strategies for patients with cancer and infections. Moreover, TCF-1 is a potential biomarker of CD8⁺ T cell functionality to predict the efficacy of immunotherapy in fighting against cancer and infections. Herein, we summarize the role of TCF-1 in T cell development and its applications in the treatment of cancer and infectious diseases.

DNA methylation mediated RSPO2 to promote follicular development in mammals

In female mammals, the proliferation, apoptosis, and estradiol-17β (E2) secretion of granulosa cells (GCs) have come to decide the fate of follicles. DNA methylation and RSPO2 gene of Wnt signaling pathway have been reported to involve in the survival of GCs and follicular development. However, the molecular mechanisms for how DNA methylation regulates the expression of RSPO2 and participates in the follicular development are not clear. In this study, we found that the mRNA and protein levels of RSPO2 significantly increased during follicular development, but the DNA methylation level of RSPO2 promoter decreased gradually. Inhibition of DNA methylation or DNMT1 knockdown could decrease the methylation level of CpG island (CGI) in RSPO2 promoter and upregulate the expression level of RSPO2 in porcine GCs. The hypomethylation of -758/-749 and -563/-553 regions in RSPO2 promoter facilitated the occupancy of transcription factor E2F1 and promoted the transcriptional activity of RSPO2. Moreover, RSPO2 promoted the proliferation of GCs with increasing the expression level of PCNA, CDK1, and CCND1 and promoted the E2 secretion of GCs with increasing the expression level of CYP19A1 and HSD17B1 and inhibited the apoptosis of GCs with decreasing the expression level of Caspase3, cleaved Caspase3, cleaved Caspase8, cleaved Caspase9, cleaved PARP, and BAX. In addition, RSPO2 knockdown promoted the apoptosis of GCs, blocked the development of follicles, and delayed the onset of puberty with decreasing the expression level of Wnt signaling pathway-related genes (LGR4 and CTNNB1) in vivo. Taken together, the hypomethylation of -758/-749 and -563/-553 regions in RSPO2 promoter facilitated the occupancy of E2F1 and enhanced the transcription of RSPO2, which further promoted the proliferation and E2 secretion of GCs, inhibited the apoptosis of GCs, and ultimately ameliorated the development of follicles through Wnt signaling pathway. This study will provide useful information for further exploration on DNA-methylation-mediated RSPO2 pathway during follicular development.

Ubiquitin-Specific Peptidase 5 is Involved in the Proliferation of Trophoblast Cells by Regulating Wnt/β-Catenin Signaling

Preeclampsia (PE) is a pathologic condition in pregnant women which accounts for the inhibition of proliferation, migration and invasion of trophoblast cells. This study aimed to investigate the regulation of ubiquitin-specific peptidase 5 (USP5) on the trophoblast cells in PE. Expressions of USP5 in the placentas of PE patients and healthy donors were examined by qRT-PCR and Western blot. Hypoxia/reoxygenation (H/R) model in trophoblast cells was further established. Cell viability was examined using CCK-8 assay. Finally, the effect of overexpression and silence of USP5 using lentivirus transduction was studied. Our results showed that USP5 was lowly expressed in the placentas of PE patients as well as in H/R-induced trophoblast cells. In the experiments of overexpression, USP5 promoted the proliferation of trophoblast cells, and up-regulated the expressions of β-catenin and the downstream signals c-Myc and Cyclin D1 in trophoblast cells. On the other hand, silence of USP5 elicited the opposite results. The overexpression of USP5 in the H/R model greatly released the H/R-induced inhibition in the trophoblast cells, and moderated the down-regulation of β-catenin and c-Myc induced by H/R. We concluded that USP5 promoted the proliferation of trophoblast cells via the up-regulation of the Wnt/β-catenin signaling pathway.

The Role of LGR4 (GPR48) in Normal and Cancer Processes

Leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) is a receptor that belongs to the superfamily of G protein-coupled receptors that can be activated by R-spondins (RSPOs), Norrin, circLGR4, and the ligand of the receptor activator of nuclear factor kappa-B (RANKL) ligands to regulate signaling pathways in normal and pathological processes. LGR4 is widely expressed in different tissues where it has multiple functions such as tissue development and maintenance. LGR4 mainly acts through the Wnt/β-catenin pathway to regulate proliferation, survival, and differentiation. In cancer, LGR4 participates in tumor progression, invasion, and metastasis. Furthermore, recent evidence reveals that LGR4 is essential for the regulation of the cancer stem cell population by controlling self-renewal and regulating stem cell properties. This review summarizes the function of LGR4 and its ligands in normal and malignant processes.

miR-196b-5p Promotes Proliferation, Migration and Invasion of Lung Adenocarcinoma Cells via Targeting RSPO2

Objective

To explore the biological role of miR-196b-5p/RSPO2 in the occurrence and development of lung adenocarcinoma (LUAD) and to provide a basis for finding new therapeutic targets for LUAD.

Methods

Differentially expressed genes were analyzed based on LUAD microarray, and the target gene of the target miRNA was predicted. qRT-PCR was used to detect the expression levels of miR-196b-5p and RSPO2 mRNA in normal human bronchial epithelial cell line BEAS-2B and LUAD cell lines A549, NCI-H1792 and NCI-H226. Western blot was used to evaluate protein expression. Cell proliferative, migratory and invasive abilities were detected by CCK-8 and transwell assays. Dual-luciferase assay was conducted to verify the targeting relationship between miR-196b-5p and RSPO2.

Results

The results of qRT-PCR showed that miR-196b-5p was significantly highly expressed in LUAD cells, and the expression level of its downstream target gene RSPO2 was significantly decreased. The results of CCK-8 and transwell assays exhibited that miR-196b-5p promoted proliferation, migration and invasion of LUAD cells, while RSPO2 inhibited the malignant progression of LUAD cells. Dual-luciferase assay confirmed the targeted binding relationship between miR-196b-5p and RSPO2. Overexpression of RSPO2 partially reversed the promotion of miR-196b-5p on proliferation, migration and invasion of LUAD cells.

Conclusion

miR-196b-5p promoted proliferation, migration and invasion of LUAD cells by targeting and down-regulating RSPO2, which provided ideas for searching new targets for the diagnosis and treatment of LUAD.

MicroRNA-377-3p targeting MMP-16 inhibits ovarian cancer cell growth, invasion, and interstitial transition

Background

To evaluate role of microRNA (miRNA)-377-3p on the remission of ovarian cancer (OC) cell proliferation, invasion, and interstitial transition in vivo and vitro.

Methods

SKOV3 cells were used as the object of in vitro research and four-week-old immunodeficient BABL/c female nude mice were used to form the xenograft model. Cell models were constructed by transfecting NC mimics, miR-377 mimic, plasmid cloning DNA (pcDNA), pc-matrix metalloproteinase (MMP)-16, or co-transfecting miR-377 mimic and pc-MMP-16. TargetScan software was used to predict the targeting relationship between miRNA-377-3p and MMP-16 in OC cells. The combination of miRNA-377-3p and MMP-16 was detected by dual luciferase report experiment. miRNA expression levels of miRNA-377-3p and MMP-16 in each transfection group cells were detected by reverse transcription-polymerase chain reaction (RT-PCR). The proliferation of SKOV3 cells were assessed by 5-ethynyl-2'-deoxyuridine (EdU) staining and microtubule formation, while the invasion ability of SKOV3 cells was detected by Transwell assay. Protein expression levels of MMP-16, survivin, Ki67, vascular endothelial growth factor (VEGF), E-cadherin, and N-cadherin were detected by Western blot (WB), and the positive cells of Ki67 and VEGF were detected by immunohistochemistry (IHC).

Results

MMP-16 overexpression markedly increased the EDU-positive cell percentage, upregulated survivin and Ki67 levels, increased the number of invasive cells per field, and enhanced VEGF and N-cadherin expression. Importantly, co-transfection of miRNA-377-3p and MMP-16 reversed these abnormal phenomena. Xenotransplantation mouse models were formed by injecting SKOV-3 cells subcutaneously. Tumor size, tumor volume, and tumor weight were all reduced in the miR-377-3p mimic–transfected group. The results of IHC indicated that Ki67 and VEGF expression were decreased in the miR-377-3p mimic–transfected group.

Conclusions

These findings indicate that miR-377-3p could be a promising therapeutic agent for OC cell growth, invasion, and interstitial transition with MMP-16 being its likely target.

Diversity in cancer invasion phenotypes indicates specific stroma regulated programs

Tumor dissemination into the surrounding stroma is the initial step in a metastatic cascade. Invasion into stroma is a non-autonomous process for cancer, and its progression depends upon the stage of cancer, as well as the cells residing in the stroma. However, a systems framework to understand how stromal fibroblasts resist, collude, or aid cancer invasion has been lacking, limiting our understanding of the role of stromal biology in cancer metastasis. We and others have shown that gene perturbation in stromal fibroblasts can modulate cancer invasion into the stroma, highlighting the active role stroma plays in regulating its own invasion. However, cancer invasion into stroma is a complex higher-order process and consists of various sub-phenotypes that together can result in an invasion. Stromal invasion exhibits a diversity of modalities in vivo. It is not well understood if these diverse modalities are correlated, or they emanate from distinct mechanisms and if stromal biology could regulate these characteristics. These characteristics include the extent of invasion, formation, and persistence of invasive forks by cancer as opposed to a collective frontal invasion, the persistence of invading velocity by leader cells at the tip of invasive forks, etc. We posit that quantifying distinct aspects of collective invasion can provide useful suggestions about the plausible mechanisms regulating these processes, including whether the process is regulated by mechanics or by intercellular communication between stromal cells and cancer. Here, we have identified the sub-characteristics of invasion, which might be indicative of broader mechanisms regulating these processes, developed methods to quantify these metrics, and demonstrated that perturbation of stromal genes can modulate distinct aspects of collective invasion. Our results highlight that the genetic state of stromal fibroblasts can regulate complex phenomena involved in cancer dissemination and suggest that collective cancer invasion into stroma is an outcome of the complex interplay between cancer and stromal fibroblasts.

HPV+ve/-ve oral-tongue cancer stem cells: A potential target for relapse-free therapy

The tongue squamous cell carcinoma (TSCC) is a highly prevalent head and neck cancer often associated with tobacco and/or alcohol abuse or high-risk human papillomavirus (HR-HPV) infection. HPV positive TSCCs present a unique mechanism of tumorigenesis as compared to tobacco and alcohol-induced TSCCs and show a better prognosis when treated. The poor prognosis and/or recurrence of TSCC is due to presence of a small subpopulation of tumor-initiating tongue cancer stem cells (TCSCs) that are intrinsically resistant to conventional chemoradio-therapies enabling cancer to relapse. Therefore, targeting TCSCs may provide efficient therapeutic strategy for relapse-free survival of TSCC patients. Indeed, the development of new TCSC targeting therapeutic approaches for the successful elimination of HPV+ve/-ve TCSCs could be achieved either by targeting the self-renewal pathways, epithelial mesenchymal transition, vascular niche, nanoparticles-based therapy, induction of differentiation, chemoradio-sensitization of TCSCs or TCSC-derived exosome-based drug delivery and inhibition of HPV oncogenes or by regulating epigenetic pathways. In this review, we have discussed all these potential approaches and highlighted several important signaling pathways/networks involved in the formation and maintenance of TCSCs, which are targetable as novel therapeutic targets to sensitize/eliminate TCSCs and to improve survival of TSCC patients.

Ablation of LGR4 signaling enhances radiation sensitivity of prostate cancer cells

AIM

Our previous study has shown that leucine-rich repeat containing GPCR-4 (LGR4, or GPR48) LGR4 plays a role in cell migration, invasion, proliferation and apoptosis of prostate cancer (PCa). In this study, we aimed to explore whether LGR4 would affect radiation response in PCa.

MATERIALS AND METHODS

LGR4 expression was silenced by shRNA transfection. qRT-PCR was employed to determine mRNA expression of LGR4 and DNA damage repair genes. Western blot was used to evaluate protein expression of LGR4, RSPO1-4, androgen receptor (AR), cyclic AMP response-element binding protein (CREB1), γH2A.X, and H2A.X. Cell proliferation was detected by CCK-8 assay and apoptosis was assayed by flow cytometry. Additionally, a xenograft model was also established to validate the role of LGR4 in PCa cells after radiation.

KEY FINDINGS

LGR4 expression was enhanced in PCa cells by radiation treatment in dose- and time-dependent means. RSPO1-4 were also upregulated post-radiation. Furthermore, LGR4 knockdown exacerbated apoptosis, reduced cell viabilities and strengthened nuclear γH2A.X staining in AR positive PCa cells but not in AR negative cells in the presence of radiation. Likewise, LGR4 ablation diminished AR and CREB1 expression induced by radiation. In contrast, RSPO1 stimulation augmented cell viabilities, promoted AR and CREB1 expression, and upregulated DNA repair gene expression, which could be reversed by enzalutamide, except for AR expression. Additionally, LGR4 knockdown further suppressed tumor growth and AR/CREB1 expression but enhanced γH2A.X expression in xenografts.

SIGNIFICANCE

In all, our study suggested that LGR4 might serve as an important regulator of radiation sensitivity in PCa.

Wogonoside Attenuates Cutaneous Squamous Cell Carcinoma by Reducing Epithelial-Mesenchymal Transition/Invasion and Cancer Stem-Like Cell Property

Purpose

Cutaneous squamous cell carcinoma (cSCC) is the most common second basal cell carcinoma in our population. Wogonoside, the main in vivo metabolite of wogonin, possesses anti-inflammatory, anti-angiogenesis and anti-cancer activities. Nevertheless, the effectiveness of wogonoside therapy on cSCC has not been clarified.

Methods

In this study, we investigated the effects of wogonoside on cell proliferation, invasion, epithelial–mesenchymal transition (EMT) and cancer stem-like cell (CSC) properties of SCL-1 and SCC12 cell lines, and the effects on tumor formation in vivo. In vitro, cells were treated with 0, 25, 50 and 100 μM wogonoside for 48 h. In vivo, SCL-1 cells were subcutaneously injected into the right thigh of mice to form xenograft tumors. Animals were randomly divided into two groups (n=10): the control group and the 80 mg/kg wogonoside group.

Results

The results showed that wogonoside attenuated proliferation, invasion and EMT of SCL-1 and SCC12 cell lines, and enhanced the rate of apoptosis. Meanwhile, wogonoside efficiently abolished the CSC traits of cSCC; the expression of CSC markers (ALDH1, SOX-2, Oct4 and CD44) and the percentage of CD133⁺ cells were remarkably downregulated. In addition, we found that wogonoside repressed the activation of both PI3K/AKT and Wnt/β-catenin pathways. In vivo, wogonoside significantly inhibited tumor formation.

Conclusion

The results indicated that wogonoside could attenuate cSCC by reducing EMT, invasion and CSC properties. The efficacy of intervention may be related to inhibition of the PI3K/Akt and Wnt/β-catenin pathways. These novel findings could furnish new ideas on the potential therapeutic application of wogonoside in cSCC cancellation and cancer intervention.

Vitexin attenuates epithelial ovarian cancer cell viability and motility in vitro and carcinogenesis in vivo via p38 and ERK1/2 pathways related VEGFA

Background

Epithelial ovarian cancer (EOC) is the most common type of ovarian tumor, however, effective treatment does not currently exist for this condition. This study evaluated the role of vitexin in mitigating EOC both in vitro and in vivo.

Method

SKOV-3 cells were used for in vitro experimentation. Xenotransplantation mouse models were set up by subcutaneously injecting mice with SKOV-3 cells. CCK8 was used to screen the optimal dose in vitro. Cell proliferation, invasion, number of microtubule nodules and apoptosis were respectively detected by colony formation assay, transwell assay, microtubule formation assay and flow cytometry. TUNEL and immunohistochemistry were used to detect tissues apoptosis and VEGF content. Western blot assay was used to detect the expression of Ki67, caspase-3, VEGFA, VEGFR2, ERK1/2 and p38.

Results

In vitro experiment, compared with the control group, 10 µL of vitexin significantly reduced Ki67 levels and enhanced tumor cell apoptosis rate. Additionally, the colony forming rate, invasive cells per field, and number of nodes/HPF in vitexin treated group decreased dramatically. The result of western blot showed that levels of p-p38/p38 and p-ERK1/2/ERK1/2 also noticeably decreased. In vivo experiment, 40 mg/kg of vitexin significantly inhibited tumor growth. In addition, vitexin significantly enhanced the percentage of tissues apoptosis, which was accompanied by a decrease in the percentage of VEGF-positive cells.

Conclusions

Vitexin decreased the proliferation and invasion of SKOV-3 cells and noticeably reduced tumor growth. These findings suggest that vitexin could be a promising therapy for EOC.