Knockdown of Sox2 Inhibits OS Cells Invasion and Migration via Modulating Wnt/β-Catenin Signaling Pathway

miR-155 promotes m6A modification of SOX2 mRNA through targeted regulation of HIF-1α and delays wound healing in diabetic foot ulcer in vitro models

OBJECTIVE

Diabetic foot ulcers (DFU) are one of the most destructive complications of diabetes mellitus. The aim of this study was to link miR-155 and SOX2 with DFU to explore the regulation of wound healing by DFU and its potential mechanism.

METHODS

Human keratinocytes (HaCaT) were induced with advanced glycation end products (AGEs) to construct DFU models in vitro. AGE-induced HaCaT cells were subjected to CCK-8 assays, flow cytometry, and wound healing assays to evaluate cell proliferation, apoptosis, and migration capacity, respectively. RT-qPCR and Western blotting were used to determine gene and protein expression levels, respectively. N6-methyladenosine (M6A) levels in total RNA were assessed using an M6A methylation quantification kit.

RESULTS

Our results suggested that the inhibition of miR-155 promoted wound healing in an in vitro DFU model, while the knockdown of HIF-1α reversed this process, and that HIF-1α was a target protein of miR-155. In addition, knockdown of HIF-1α promoted the m6A level of SOX2 mRNA, inhibited the expression of SOX2, and inhibited the activation of the EGFR/MEK/ERK signaling pathway, thus inhibiting the proliferation and migration of HaCaT cells and promoting the apoptosis of HaCaT cells, while overexpression of SOX2 reversed this effect. We also found that METTL3 knockdown had the opposite effect of HIF-1α knockdown.

CONCLUSIONS

Inhibition of miR-155 promoted the expression of HIF-1α and attenuated the m6A modification of SOX2 mRNA, thereby promoting the expression of SOX2 and activating the downstream EGFR/MEK/ERK signaling pathway to promote wound healing in an in vitro DFU model.

The tale of SOX2: Focusing on lncRNA regulation in cancer progression and therapy

Long non-coding RNAs (lncRNAs) have emerged as influential contributors to diverse cellular processes, which regulate gene function and expression via multiple mechanistic pathways. Therefore, it is essential to exploit the structures and interactions of lncRNAs to comprehend their mechanistic functions within cells. A growing body of evidence has revealed that deregulated lncRNAs are involved in multiple regulations of malignant events including cell proliferation, growth, invasion, and metabolism. SRY-related high mobility group box (SOX)2, a well-recognized member of the SOX family, is commonly overexpressed in various types of cancer, contributing to tumor progression and maintenance of stemness. Emerging studies have shown that lncRNAs interact with SOX2 to remarkably contribute to carcinogenesis and disease states. This review elaborates on the crosstalk between the intricate and complicated functions of lncRNAs and SOX2 in the context of malignant diseases. We elucidate distinct molecular mechanisms that contribute to the onset/advancement of cancer, indicating that lncRNAs/SOX2 axes hold immense promise for potential therapeutic targets. Furthermore, we delve into the modalities of emerging feasible treatment options for targeting lncRNAs, highlighting the limitations of such therapies and providing novel insights into further ameliorations of targeted strategies of lncRNAs to promote the clinical implications. Translating current discoveries into clinical applications could ultimately boost improved survival and prognosis of cancer patients.

Regulatory role of miRNAs on Wnt/β-catenin signaling in tumorigenesis of glioblastoma

Glioblastoma (GBM) is one of the most aggressive tumors in the brain with high mortality worldwide. Despite recent advances in therapeutic strategies, the survival rate remains low in patients with GBM. The pathogenesis of GBM is a very complicated process involving various genetic mutations affecting several oncogenic signaling pathways like Wnt/β-catenin axis. Overactivation of the Wnt/β-catenin signaling pathway is associated with decreased survival and poor prognosis in patients with GBM. MicroRNAs (miRNAs) were shown to play important roles in the regulation of cell proliferation, differentiation, apoptosis, and tumorigenesis by modulating the expression of their target genes. Aberrant expression of miRNAs were reported in various human malignancies including GBM, breast, colorectal, liver, and prostate cancers, but little is known about their cellular mechanisms. Therefore, recognition of the expression profile and regulatory effects of miRNAs on the Wnt/β-catenin pathway may offer a novel approach for the classification, diagnosis, prognosis, and treatment of patients with GBM. This review summarizes previous data on the modulatory role of miRNAs on the Wnt/β-catenin pathway implicated in tumorigenesis of GBM.

Cellular and Genetic Background of Osteosarcoma

Osteosarcoma describes a tumor of mesenchymal origin with an annual incidence rate of four to five people per million. Even though chemotherapy treatment has shown success in non-metastatic osteosarcoma, metastatic disease still has a low survival rate of 20%. A targeted therapy approach is limited due to high heterogeneity of tumors, and different underlying mutations. In this review, we will summarize new advances obtained by new technologies, such as next generation sequencing and single-cell sequencing. These new techniques have enabled better assessment of cell populations within osteosarcoma, as well as an understanding of the molecular pathogenesis. We also discuss the presence and properties of osteosarcoma stem cells-the cell population within the tumor that is responsible for metastasis, recurrence, and drug resistance.

Self-Renewal and Pluripotency in Osteosarcoma Stem Cells' Chemoresistance: Notch, Hedgehog, and Wnt/β-Catenin Interplay with Embryonic Markers

Osteosarcoma is a highly malignant bone tumor derived from mesenchymal cells that contains self-renewing cancer stem cells (CSCs), which are responsible for tumor progression and chemotherapy resistance. Understanding the signaling pathways that regulate CSC self-renewal and survival is crucial for developing effective therapies. The Notch, Hedgehog, and Wnt/β-Catenin developmental pathways, which are essential for self-renewal and differentiation of normal stem cells, have been identified as important regulators of osteosarcoma CSCs and also in the resistance to anticancer therapies. Targeting these pathways and their interactions with embryonic markers and the tumor microenvironment may be a promising therapeutic strategy to overcome chemoresistance and improve the prognosis for osteosarcoma patients. This review focuses on the role of Notch, Hedgehog, and Wnt/β-Catenin signaling in regulating CSC self-renewal, pluripotency, and chemoresistance, and their potential as targets for anti-cancer therapies. We also discuss the relevance of embryonic markers, including SOX-2, Oct-4, NANOG, and KLF4, in osteosarcoma CSCs and their association with the aforementioned signaling pathways in overcoming drug resistance.

Insights into the multi-faceted role of Pioneer transcription factors in glioma formation and progression with targeting options

Pioneer transcription factors (TFs) present an important subtype of transcription factors which are vital for cell programming during embryonic development and cellular memory during mitotic growth, as well as cell fate reprogramming. Pioneer TFs can engage specific target binding sites on nucleosomal DNA to attract chromatin remodeling complexes, cofactors, and other transcription factors, ultimately controlling gene expression by shaping locally the epigenome. The priority of binding that they exhibit in contrast to other transcription factors and their involvement in crucial events regarding cell fate, has implicated their aberrant function in the pathogenesis of several disorders including carcinogenesis. Emerging experimental data indicate that certain Pioneer TFs are highly implicated in gliomas development, in neoplastic cell proliferation, angiogenic processes, resistance to therapy, and patient survival. Herein, we describe the main structural characteristics and functional mechanisms of pioneer TFs, focusing on their central role in the pathogenesis and progression of gliomas. We further highlight the current treatment options ranging from natural agents (oleanolic acid) to a variety of chemical compounds (APR-246, COTI-2) and discuss potential delivery systems, including nanoparticles, viral vectors, and intracellular protein delivery techniques.

MicroRNAs and osteosarcoma: Potential targets for inhibiting metastasis and increasing chemosensitivity

Osteosarcoma (OS) is the third most common cancer in young adults after lymphoma and brain cancer. Metastasis, like other cellular events, is dependent on signaling pathways; a series of changes in some proteins and signaling pathways pave the way for OS cells to invade and migrate. Ezrin, TGF-β, Notch, RUNX2, matrix metalloproteinases (MMPs), Wnt/β-catenin, and phosphoinositide 3-kinase (PI3K)/AKT are among the most important of these proteins and signaling pathways. Despite the improvements in treating OS, the overall survival of patients suffering from the metastatic disease has not experienced any significant change after surgical treatments and chemotherapy and 5-years overall survival in patients with metastatic OS is about 20%. Studies have shown that overexpression or inhibition of some microRNAs (miRNAs) has significant effects in limiting the invasion and migration of OS cells. The results of these studies highlight the potential of the clinical application of some miRNA mimics and miRNA inhibitors (antagomiRs) to inhibit OS metastasis in the future. In addition, some studies have shown that miRNAs are associated with the most important drug resistance mechanisms in OS, and some miRNAs are highly effective targets to increase chemosensitivity. The results of these studies suggest that miRNA mimics and antagomiRs may be helpful to increase the efficacy of conventional chemotherapy drugs in the treatment of metastatic OS. In this article, we discussed the role of various signaling pathways and the involved miRNAs in the metastasis of OS, attempting to provide a comprehensive review of the literature on OS metastasis and chemosensitivity.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

Modeling the Tumor Microenvironment and Pathogenic Signaling in Bone Sarcoma

Investigations of cancer biology and screening of potential therapeutics for efficacy and safety begin in the preclinical laboratory setting. A staple of most basic research in cancer involves the use of tissue culture plates, on which immortalized cell lines are grown in monolayers. However, this practice has been in use for over six decades and does not account for vital elements of the tumor microenvironment that are thought to aid in initiation, propagation, and ultimately, metastasis of cancer. Furthermore, information gleaned from these techniques does not always translate to animal models or, more crucially, clinical trials in cancer patients. Osteosarcoma (OS) and Ewing sarcoma (ES) are the most common primary tumors of bone, but outcomes for patients with metastatic or recurrent disease have stagnated in recent decades. The unique elements of the bone tumor microenvironment have been shown to play critical roles in the pathogenesis of these tumors and thus should be incorporated in the preclinical models of these diseases. In recent years, the field of tissue engineering has leveraged techniques used in designing scaffolds for regenerative medicine to engineer preclinical tumor models that incorporate spatiotemporal control of physical and biological elements. We herein review the clinical aspects of OS and ES, critical elements present in the sarcoma microenvironment, and engineering approaches to model the bone tumor microenvironment. Impact statement The current paradigm of cancer biology investigation and therapeutic testing relies heavily on monolayer, monoculture methods developed over half a century ago. However, these methods often lack essential hallmarks of the cancer microenvironment that contribute to tumor pathogenesis. Tissue engineers incorporate scaffolds, mechanical forces, cells, and bioactive signals into biological environments to drive cell phenotype. Investigators of bone sarcomas, aggressive tumors that often rob patients of decades of life, have begun to use tissue engineering techniques to devise in vitro models for these diseases. Their efforts highlight how critical elements of the cancer microenvironment directly affect tumor signaling and pathogenesis.

SOX2 is a positive regulator of osteoclast differentiation

Elucidating the mechanism underlying osteoclast differentiation is important to improve our understanding of the pathophysiologies related to skeletal diseases and osteolytic metastasis in cancer. Sex-determining region Y-box containing gene 2 (SOX2), a stemness marker, is known to affect osteoblast differentiation and cancer metastasis. However, its role in osteoclastogenesis has not been investigated to date. Here, we report that SOX2 protein and mRNA expression was upregulated during osteoclast differentiation. The overexpression or knockdown of SOX2 in osteoclast precursor cells enhanced or suppressed, respectively, receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation and migration, and nuclear factor of activated T-cell c1 (NFATc1) and factor-associated suicide ligand (FASL) expression. In addition, epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase (ERK) activation were regulated by SOX2 expression; both EGFR and ERK inhibitors abrogated the SOX2 overexpression-induced increase in osteoclast differentiation and NFATc1 expression under RANKL stimulation. Overall, these results suggest SOX2 as a positive regulatory factor during osteoclast differentiation partly through the EGFR and ERK signaling pathways, highlighting a new potential target for restoring abnormal osteoclast activation.

The function of SOX2 in breast cancer and relevant signaling pathway

OBJECTIVE

The purpose of this study was to explore the functional roles of SOX2 in the progression of breast cancer and relevant molecular mechanism.

METHODS

A total of 108 breast cancer patients were included, and breast cancer cell line MDA-MB-231 was selected for this research. Real time-qualitative polymerase chain reaction (RT-qPCR) was conducted to measure the expression level of SOX2 mRNA. MTT and Transwell assays were used to detected the proliferation, migration and invasion of breast cancer cells, respectively. Luciferase reporter assay was conducted to reveal the relationship of SOX2 with PTEN. Western blot was performed to detect the expressions of Wnt/β-catenin pathway-related proteins.

RESULTS

The expression of SOX2 mRNA was up-regulated in breast cancer tissues and cells (P < 0.001). SOX2 expression was significantly associated with TNM stage and lymph node metastasis of breast cancer patients (P < 0.05). SOX2 knockdown significantly inhibited the proliferation, migration and invasion of breast cancer cells (P < 0.05). PTEN was a direct target of SOX2. The inhibition of PTEN could significantly suppress the progression of breast cancer cells with SOX2 overexpression. SOX2 knockdown also inhibited the expressions of β-catenin, TCP-4, FZD7, C-myc and MMP-7 proteins. Moreover, PTEN knockdown reversed the results caused by SOX2 overexpression, that is, increased expressions of β-catenin, TCP-4, FZD7, C-myc and MMP-7 proteins (P < 0.05).

CONCLUSION

SOX2 promotes the progression of breast cancer through activating Wnt/β-catenin signaling pathway via regulating PTEN.

Histone methyltransferase NSD2 regulates apoptosis and chemosensitivity in osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumour. However, the genetic basis for the pathogenesis of OS remains elusive. In this study, we uncovered the role of the histone methyltransferase NSD2 in regulating tumourigenesis and chemosensitivity in OS. We show that NSD2 knockdown leads to increased apoptosis in OS cells in vitro and in vivo. Additionally, NSD2 knockdown significantly enhances the efficacy of cisplatin against OS cells and accordingly inhibits properties associated with cancer stem cells (CSCs). Furthermore, RNA sequencing (RNAseq) and Gene Ontology (GO) analysis revealed that NSD2 promotes transcription of genes associated with negative regulation of apoptotic signalling pathways and CSC properties. The results of chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR) assays indicated that NSD2 knockdown leads to decreased H3K36me2 modification at BCL2 and SOX2 loci, thus inhibiting the transcription of these two genes that are closely correlated with apoptosis, CSC properties and chemosensitivity in OS cells. Pathway analysis demonstrated that the ERK and AKT pathways mediate the regulation of OS progression and chemosensitivity by NSD2. Overall, our study is the first to uncover the function of NSD2 in OS chemosensitivity. NSD2 regulates the expression of the apoptosis regulatory proteins BCL2 and SOX2 through the ERK and AKT pathways. Our results suggest that NSD2 is a new target for combined chemotherapy and is a prognostic factor for OS.

MiR-374a Activates Wnt/β-Catenin Signaling to Promote Osteosarcoma Cell Migration by Targeting WIF-1

MiR-374a was proved to take part in the initiation and development of several cancers. However, the molecular mechanism of miR-374a in osteosarcoma (OS) cells remains unclear. The aim of our research was to investigate the role of miR-374a in OS cells migration and clarify the potential mechanisms. Quantitative real-time PCR (qRT-PCR) and western blot analysis were applied to evaluate the expression of miR-374a and Wnt inhibitory factor-1 (WIF-1). Bioinformatical methods and luciferase reporter assay were carried out to predict and confirm the combination of miR-374a and WIF-1. Transwell and wound healing assays were performed to detect the migration capacity of OS cells. Lithium chloride (LiCl) was used to investigate the role of LiCl-activated Wnt/β-catenin signaling pathway in regulating cell migration. Our studies revealed that miR-374a was up-regulated whereas WIF-1 was down-regulated in OS cells. Besides, WIF-1 was the target of miR-374a by performing luciferase reporter assay. By transfection of miR-374a inhibitor and/or WIF-1 siRNA to OS cells, we found that miR-374a promoted the migration of OS cells. In addition, the inhibition of WIF-1 abolished the miR-374a inhibitor-induced migration suppression of OS cells. LiCl experiment revealed that miR-374a promoted OS cells migration by regulating Wnt/β-catenin signaling. In conclusion, miR-374a promotes OS cells migration by activating Wnt/β-catenin signaling pathway via targeting WIF-1.