Identification of Sox6 as a regulator of pancreatic cancer development

Cisplatin-based miRNA delivery strategy inspired by the circCPNE1/miR-330-3p pathway for oral squamous cell carcinoma

Circular RNAs (circRNAs) are ideal biomarkers of oral squamous cell carcinoma (OSCC) because of their highly stable closed-loop structure, and they can act as microRNA (miRNA) sponges to regulate OSCC progression. By analyzing clinical samples, we identified circCPNE1, a dysregulated circRNA in OSCC, and its expression level was negatively correlated with the clinical stage of OSCC patients. Gain-of-function assays revealed the tumor-suppressive effect of circCPNE1, which was then identified as a miR-330-3p sponge. MiR-330-3p was recognized as a tumor promoter in multiple studies, consistent with our finding that it could promote the proliferation, migration, and invasion of OSCC cells. These results indicated that selective inhibition of miR-330-3p could be an effective strategy to inhibit OSCC progression. Therefore, we designed cationic polylysine-cisplatin prodrugs to deliver antagomiR-330-3p (a miRNA inhibitory analog) via electrostatic interactions to form PP@miR nanoparticles (NPs). Paratumoral administration results revealed that PP@miR NPs effectively inhibited subcutaneous tumor progression and achieved partial tumor elimination (2/5), which confirmed the critical role of miR-330-3p in OSCC development. These findings provide a new perspective for the development of OSCC treatments.

Transcriptional repression of the oncofetal LIN28B gene by the transcription factor SOX6

The identification of regulatory networks contributing to fetal/adult gene expression switches is a major challenge in developmental biology and key to understand the aberrant proliferation of cancer cells, which often reactivate fetal oncogenes. One key example is represented by the developmental gene LIN28B, whose aberrant reactivation in adult tissues promotes tumor initiation and progression. Despite the prominent role of LIN28B in development and cancer, the mechanisms of its transcriptional regulation are largely unknown. Here, by using quantitative RT-PCR and single cell RNA sequencing data, we show that in erythropoiesis the expression of the transcription factor SOX6 matched a sharp decline of LIN28B mRNA during human embryo/fetal to adult globin switching. SOX6 overexpression repressed LIN28B not only in a panel of fetal-like erythroid cells (K562, HEL and HUDEP1; ≈92% p < 0.0001, 54% p = 0.0009 and ≈60% p < 0.0001 reduction, respectively), but also in hepatoblastoma HepG2 and neuroblastoma SH-SY5H cells (≈99% p < 0.0001 and ≈59% p < 0.0001 reduction, respectively). SOX6-mediated repression caused downregulation of the LIN28B/Let-7 targets, including MYC and IGF2BP1, and rapidly blocks cell proliferation. Mechanistically, Lin28B repression is accompanied by SOX6 physical binding within its locus, suggesting a direct mechanism of LIN28B downregulation that might contribute to the fetal/adult erythropoietic transition and restrict cancer proliferation.

CircTAOK1 regulates high glucose induced inflammation, oxidative stress, ECM accumulation, and apoptosis in diabetic nephropathy via targeting miR-142-3p/SOX6 axis

BACKGROUND

Diabetic nephropathy (DN) is a complication caused by diabetes. Circular RNAs (circRNAs) are a kind of RNA with a closed circular structure, which has high stability and is involved in many disease-related processes. The mechanism of circRNA TAO kinase 1 (circTAOK1) in the pathogenesis and development of DN is unclear.

METHODS

CircTAOK1, microRNA (miR)-142-3p, and sex-determining region Y-box transcription factor 6 (SOX6) mRNA levels were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 (CCK8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to analyze cell proliferation. Cell cycle distribution was detected by flow cytometry. Western blot assay was performed to test B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax), cleaved-caspase 3, and fibronectin (FN), collagen I (Col I), and collagen IV (Col IV) protein levels. ELISA assay was used to measure interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor (TNF-α) levels. The reactive oxygen species (ROS) and malondialdehyde (MDA) levels and the superoxide dismutase (SOD) activity were assessed by the corresponding kits. And the correlation between miR-142-3p and circTAOK1 or SOX6 was confirmed by dual luciferase reporter assay, RNA immunoprecipitation assay and RNA pull down assay.

RESULTS

CircTAOK1 and SOX6 expression levels were up-regulated, while miR-142-3p expression was down-regulated in DN serum and HG-treated HK-2 cells. Knockdown of circTAOK1 could inhibit cell injury of HG-induced HK-2 cells. The inhibitory effect of circTAOK1 knockdown on HG-induced HK-2 cell injury was restored by miR-142-3p downregulation. CircTAOK1 acted as a sponge for miR-142-3p, and SOX6 was targeted by miR-142-3p. The overexpression of SOX6 could recover the effect of miR-142-3p overexpression on HG-induced HK-2 cell injury. CircTAOK1 regulated the expression of SOX6 by targeting miR-142-3p.

CONCLUSION

CircTAOK1 knockdown inhibited HG-induced HK-2 cell damage in DN by the miR-142-3p/SOX6 axis.

SOX on tumors, a comfort or a constraint?

The sex-determining region Y (SRY)-related high-mobility group (HMG) box (SOX) family, composed of 20 transcription factors, is a conserved family with a highly homologous HMG domain. Due to their crucial role in determining cell fate, the dysregulation of SOX family members is closely associated with tumorigenesis, including tumor invasion, metastasis, proliferation, apoptosis, epithelial-mesenchymal transition, stemness and drug resistance. Despite considerable research to investigate the mechanisms and functions of the SOX family, confusion remains regarding aspects such as the role of the SOX family in tumor immune microenvironment (TIME) and contradictory impacts the SOX family exerts on tumors. This review summarizes the physiological function of the SOX family and their multiple roles in tumors, with a focus on the relationship between the SOX family and TIME, aiming to propose their potential role in cancer and promising methods for treatment.

Propranolol inhibits EMT and metastasis in breast cancer through miR-499-5p-mediated Sox6

PURPOSE

This study will focus on 4T1 cells, a murine mammary adenocarcinoma cell line, as the primary research subject. We aim to investigate the inhibitory effects and mechanisms of propranolol on epithelial-mesenchymal transition (EMT) in breast cancer cells, aiming to elucidate this phenomenon at the miRNA level.

METHODS

In this study, the EMT inhibitory effect of propranolol was observed through in vitro and animal experiments. For the screening of potential target miRNAs and downstream target genes, second-generation sequencing (SGS) and bioinformatics analysis were conducted. Following the screening process, the identified target miRNAs and their respective target genes were confirmed using various experimental methods. To confirm the target miRNAs and target genes, Western Blot (WB), reverse transcription polymerase chain reaction (RT-PCR), and immunofluorescence experiments were performed.

RESULTS

In this study, we found that propranolol significantly reduced lung metastasis in 4T1 murine breast cancer cells (p < 0.05). In vitro and in vivo experiments demonstrated that propranolol inhibited the epithelial-mesenchymal transition (EMT) as evidenced by Western Blot analysis (p < 0.05). Through next-generation sequencing (SGS), subsequent bioinformatics analysis, and PCR validation, we identified a marked downregulation of miR-499-5p (p < 0.05), suggesting its potential involvement in mediating the suppressive effects of propranolol on EMT. Overexpression of miR-499-5p promoted EMT, migration, and invasion of 4T1 cells, and these effects were not reversed or attenuated by propranolol (Validated via Western Blot, wound healing assay, transwell migration, and invasion assays, p < 0.05). Sox6 was identified as a functional target of miR-499-5p, with its downregulation correlating with the observed EMT changes (p < 0.05). Silencing Sox6 or overexpressing miR-499-5p inhibited Sox6 expression, further promoting the processes of EMT, invasion, and migration in 4T1 cells. Notably, these effects were not alleviated by propranolol (validated via Western Blot, wound healing assay, transwell migration, and invasion assays, p < 0.05). The direct interaction between miR-499-5p and Sox6 mRNA was confirmed by dual-luciferase reporter gene assay.

CONCLUSION

These results suggest that propranolol may have potential as a therapeutic agent for breast cancer treatment by targeting EMT and its regulatory mechanisms.

Sox6 impairs the adipogenic commitment of mesenchymal stem cells by targeting lysyl oxidase and preadipocyte factor 1

The commitment of mesenchymal stem cells (MSCs) to preadipocytes and the termination of differentiation to adipocytes are critical for maintaining systemic energy homeostasis. However, our knowledge of the molecular mechanisms governing the commitment of MSCs to preadipocytes and the subsequent termination of their differentiation into adipocytes remain limited. Additionally, the role of Sox6 sex-determining region Y (SRY)-box6 (Sox6), a transcription factor that regulates gene transcription, is reportedly involved in various cellular processes, including adipogenesis; however, its function in regulating preadipocyte development and the factors involved in the termination of adipogenic differentiation remain unexplored. Therefore, we investigated the role of Sox6 in regulating the differentiation of adipocytes by monitoring the effects of its overexpression in C3H10T1/2 cells (in vitro) and C57BL/6J mouse (in vivo) models of adipogenesis. We observed lower Sox6 expression in the adipose tissue of obese mice than that in control mice. Sox6 overexpression inhibited the differentiation of MSC by directly binding to the lysyl oxidase (Lox) and preadipocyte factor 1 (Pref1) promoters, which was potentiated by histone deacetylase-1(HDAC1). Our findings suggest that Sox6 is a key regulator of MSC commitment to adipocytes; therefore, targeting the Sox6-mediated regulation of this process could offer potential therapeutic avenues for addressing obesity and related metabolic disorders.

KNOCKDOWN OF CIRC_0001379 ATTENUATES HYPOXIA/REOXYGENATION-INDUCED CARDIOMYOCYTE APOPTOSIS AND INFLAMMATORY RESPONSE BY MIR-98-5P/SOX6 AXIS

ABSTRACT

Background: Aberrant expression of circular RNAs (circRNAs) has been revealed to have crucial roles in the pathological processes of cardiovascular disease. Here, this study aimed to investigate the role and mechanism of circ_0001379 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury to explore the potential action of circ_0001379 in acute myocardial infarction (AMI). Methods: Levels of genes and proteins were examined by quantitative real-time polymerase chain reaction and western blot. Cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, and flow cytometry were used to detect cardiomyocyte proliferation and apoptosis, respectively. The activity of IL-1β, IL-6, and TNF-α was determined by ELISA analysis. The target relationship between miR-98-5p and circ_0001379 or SOX6 (SRY-Box Transcription Factor 6) was verified by dual-luciferase reporter and RNA immunoprecipitation assays. Results: Circ_0001379 was highly expressed in AMI mouse model and H/R-induced cardiomyocytes. Functionally, circ_0001379 silencing attenuated H/R-evoked cardiomyocyte apoptosis and inflammatory response. Mechanistically, circ_0001379 functioned as a sponge for miR-98-5p, which directly targeted SOX6. Moreover, circ_0001379 could regulate SOX6 expression via sponging miR-98-5p. Further rescue experiments showed that inhibition of miR-98-5p reversed the protective effects of circ_0001379 silencing on H/R-induced cardiomyocytes. Besides that, miR-98-5p overexpression abolished H/R-evoked cardiomyocyte apoptosis and inflammatory response, while this condition was abated by SOX6. Conclusion: Circ_0001379 silencing protects cardiomyocytes from H/R-induced apoptosis and inflammatory response by miR-98-5p/SOX6 axis, suggesting a novel therapeutic strategy for AMI prevention.

Clinical implications and genetical insights of SOX6 expression in acute myeloid leukemia

BACKGROUND

Transcription factor SOX6 belongs to Sry-related high-mobility-group box (SOX) family, has been reported to be downregulated and acts as a tumor-suppressor gene in various solid tumors, but in acute myeloid leukemia (AML) is incompletely understood.

METHODS

The SOX6 expression was analyzed between AML patients and normal controls from public data and our research cohort. Correlations between SOX6 expression and clinical, genetic features together with survival were further analyzed.

RESULTS

In both public and our present datasets, we demonstrated that SOX6 expression is notably downregulated in AML patients compared with normal controls. Moreover, the expression level of SOX6 was dynamic, along with the disease status. SOX6 was significantly decreased in relapsed/refractory AML compared with complete remission AML. Clinically, SOX6 underexpression was significantly correlated with bone marrow blasts, and WBC counts. Furthermore, decreased expression of SOX6 was more common in core binding factor AML (CBF-AML), rarely found in complex karyotype AML (CK-AML), and correlated with FLT3 mutations. By survival analyses, low-expression of SOX6 was associated with shorter overall survival (OS) and event-free survival (EFS) among cytogenetic normal AML (CN-AML) patients. Moreover, both univariate and multivariate analyses showed that low SOX6 expression was an independent unfavorable prognostic biomarker for CN-AML.

CONCLUSIONS

Our findings indicated that SOX6 underexpression, as a frequent event in AML, was associated with genetic abnormalities and prognosis in AML. SOX6 might be a valuable biomarker for risk stratification, predicting prognosis and relapse of AML.

Circ_0123996 promotes the proliferation, inflammation, and fibrosis of mesangial cells by sponging miR-203a-3p to upregulate SOX6 in diabetic nephropathy

Circular RNA has been reported to participate in human diseases including diabetic nephropathy (DN). However, the role and mechanism of circ_0123996 in DN need to be further explored. Relative expression levels of circ_0123996, microRNA (miR)-203a-3p, SRY-box 6 (SOX6), and inflammatory cytokines were determined using quantitative real-time PCR. Western blot analysis was used to detect the protein expression of SOX6 and fibrosis-related markers. Cell proliferation was measured using the Cell Counting Kit 8 assay. The interaction between miR-203a-3p and circ_0123996 or SOX6 was verified using the dual-luciferase reporter assay. The circ_0123996 and SOX6 expression were increased and the miR-203a-3p expression was decreased in high glucose-induced mesangial cells. Silenced circ_0123996 could hinder the proliferation, inflammation, and fibrosis of mesangial cells. In terms of mechanism, circ_0123996 could sponge miR-203a-3p to positively regulate SOX6 expression. Function experiments revealed that miR-203a-3p inhibitor could abolish the regulation of circ_0123996 silencing on mesangial cell proliferation, inflammation, and fibrosis. In addition, the knockdown of SOX6 could inhibit mesangial cell proliferation, inflammation, and fibrosis. Also, SOX6 overexpression could reverse the regulation of circ_0123996 silencing on mesangial cell progression. In summary, our data revealed that circ_0123996 promoted the proliferation, inflammation, and fibrosis of mesangial cells via modulating the miR-203a-3p/SOX6 axis, suggesting that circ_0123996 might be a target for alleviating DN progression.

MicroRNA-mediated regulation of key signaling pathways in hepatocellular carcinoma: A mechanistic insight

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. The molecular pathogenesis of HCC varies due to the different etiologies and genotoxic insults. The development of HCC is characterized by complex interactions between several etiological factors that result in genetic and epigenetic changes in proto-onco and/or tumor suppressor genes. MicroRNAs (miRNAs) are short non-coding RNAs that also can act as oncomiRs or tumor suppressors regulating the expression of cancer-associated genes post-transcriptionally. Studies revealed that several microRNAs are directly or indirectly involved in cellular signaling, and dysregulation of those miRNAs in the body fluids or tissues potentially affects key signaling pathways resulting in carcinogenesis. Therefore, in this mini-review, we discussed recent progress in microRNA-mediated regulation of crucial signaling networks during HCC development, concentrating on the most relevant ones such as PI3K/Akt/mTOR, Hippo-YAP/TAZ, and Wnt/β-catenin, which might open new avenues in HCC management.

Association between miR-146a rs2910164, miR-196a2 rs11614913, and miR-499 rs3746444 polymorphisms and the risk of esophageal carcinoma: A case-control study

MicroRNAs (miRNAs) are a group of small, non‐coding, and endogenous RNAs that regulate gene expression and over 50% of them are located at cancer‐related genomic regions or fragile sites. According to previous studies there is significant association of miRNA single nucleotide polymorphisms (SNPs) with tumorigenesis (e.g., esophageal cancer, hepatocellular cancer, gastric cancer, bladder cancer, breast cancer, lung cancer, and colon cancer), however, the conclusions have been inconsistent. To investigate the relationship between miR‐146a rs2910164 C > G, miR‐196a2 rs11614913 T > C, and miR‐499 rs3746444 A > G polymorphisms and the susceptibility to esophageal squamous cell cancer (ESCC) in the Chinese Han nationality, we recruited 829 cases and 1522 controls in our study. In this case–control study, our results suggest that the rs3746444 GG genotype increased ESCC risk [homozygote model: adjusted odds ratio (OR), 2.26; 95% CI, 1.33–3.83; p = 0.003, recessive model: adjusted OR, 2.34; 95% CI, 1.38–3.96; p = 0.002], which remained consistent after Bonferroni correction. There was no association of rs11614913 and rs2910164 polymorphisms with ESCC. After adjusting by age, sex, smoking, and drinking status and body mass index (BMI), the multiple logistic analysis suggested that rs11614913 T → C variation reduced ESCC susceptibility in females and in the ≥63 years old subgroups, while rs2910164 C → G variation increased ESCC risk in both two BMI subgroups.

N6-methyladenosine modification of CENPK mRNA by ZC3H13 promotes cervical cancer stemness and chemoresistance

BACKGROUND

Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis. In the current study, we determined the relevant players and role of N⁶-methyladenine (m⁶A) RNA methylation in cervical cancer progression.

METHODS

The roles of m⁶A RNA methylation and centromere protein K (CENPK) in cervical cancer were analyzed using bioinformatics analysis. Methylated RNA immunoprecipitation was adopted to detect m⁶A modification of CENPK mRNA. Human cervical cancer clinical samples, cell lines, and xenografts were used for analyzing gene expression and function. Immunofluorescence staining and the tumorsphere formation, clonogenic, MTT, and EdU assays were performed to determine cell stemness, chemoresistance, migration, invasion, and proliferation in HeLa and SiHa cells, respectively. Western blot analysis, co-immunoprecipitation, chromatin immunoprecipitation, and luciferase reporter, cycloheximide chase, and cell fractionation assays were performed to elucidate the underlying mechanism.

RESULTS

Bioinformatics analysis of public cancer datasets revealed firm links between m⁶A modification patterns and cervical cancer prognosis, especially through ZC3H13-mediated m⁶A modification of CENPK mRNA. CENPK expression was elevated in cervical cancer, associated with cancer recurrence, and independently predicts poor patient prognosis [hazard ratio = 1.413, 95% confidence interval = 1.078 - 1.853, P = 0.012]. Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo (P < 0.001). We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK with β-catenin, which promoted β-catenin expression and nuclear translocation, facilitated p53 ubiquitination, and led to activation of Wnt/β-catenin signaling, but suppression of the p53 pathway. This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness, DNA damage repair pathways necessary for cisplatin/carboplatin resistance, epithelial-mesenchymal transition involved in metastasis, and DNA replication that drove tumor cell proliferation.

CONCLUSIONS

CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.

Identification of SOX6 and SOX12 as Prognostic Biomarkers for Clear Cell Renal Cell Carcinoma: A Retrospective Study Based on TCGA Database

Background

The SOX gene family has been proven to display regulatory effects on numerous diseases, particularly in the malignant progression of neoplasms. However, the molecular functions and action mechanisms of SOX genes have not been clearly elucidated in clear cell renal cell carcinoma (ccRCC). We aimed to explore the expression status, prognostic values, clinical significances, and regulatory actions of SOX genes in ccRCC.

Methods

RNA-sequence data and clinical information derived from The Cancer Genome Atlas (TCGA) database was used for this study. Dysregulated SOX genes between the normal group and ccRCC group were screened using the Wilcoxon signed-rank test. The Kaplan-Meier analysis and univariate Cox analysis methods were used to estimate the overall survival (OS) and disease-specific survival (DSS) differences between different groups. The independent prognostic factors were identified by the use of uni- and multivariate assays. Subsequently, the Wilcoxon signed-rank test or Kruskal-Wallis test and the chi-square test or Fisher exact probability methods were employed to explore the association between clinicopathological variables and SOX genes. Finally, CIBERSORT was applied to study the samples and examine the infiltration of immune cells between different groups.

Results

Herein, 12 dysregulated SOX genes in ccRCC were screened. Among them, two independent prognostic SOX genes (SOX6 and SOX12) were identified. Further investigation results showed that SOX6 and SOX12 were distinctly associated with clinicopathological features. Furthermore, functional enrichment analysis revealed that SOX6 and SOX12 were enriched in essential biological processes and signaling pathways. Finally, we found that the SOX6 and SOX12 expression levels were correlated with tumor-infiltrating immune cells (TIICs).

Conclusion

The pooled analyses showed that SOX6 and SOX12 could serve as promising biomarkers and therapeutic targets of patients with ccRCC.

Cancer Cells Retrace a Stepwise Differentiation Program during Malignant Progression

Pancreatic neuroendocrine tumors (PanNET) comprise two molecular subtypes, relatively benign islet tumors (IT) and invasive, metastasis-like primary (MLP) tumors. Until now, the origin of aggressive MLP tumors has been obscure. Herein, using multi-omics approaches, we revealed that MLP tumors arise from IT via dedifferentiation following a reverse trajectory along the developmental pathway of islet β cells, which results in the acquisition of a progenitor-like molecular phenotype. Functionally, the miR-181cd cluster induces the IT-to-MLP transition by suppressing expression of the Meis2 transcription factor, leading to upregulation of a developmental transcription factor, Hmgb3. Notably, the IT-to-MLP transition constitutes a distinct step of tumorigenesis and is separable from the classic proliferation-associated hallmark, temporally preceding accelerated proliferation of cancer cells. Furthermore, patients with PanNET with elevated HMGB3 expression and an MLP transcriptional signature are associated with higher-grade tumors and worse survival. Overall, our results unveil a new mechanism that modulates cancer cell plasticity to enable malignant progression. SIGNIFICANCE: Dedifferentiation has long been observed as a histopathologic characteristic of many cancers, albeit inseparable from concurrent increases in cell proliferation. Herein, we demonstrate that dedifferentiation is a mechanistically and temporally separable step in the multistage tumorigenesis of pancreatic islet cells, retracing the developmental lineage of islet β cells.This article is highlighted in the In This Issue feature, p. 2355.

Characterizing therapeutic signatures of transcription factors in cancer by incorporating profiles in compound treated cells

MOTIVATION

Cancers are promoted by abnormal alterations in biological processes, such as cell cycle and apoptosis. An immediate reason for those aberrant processes is the deregulation of their involved transcription factors (TFs). Thus, the deregulated TFs in cancer have been experimented as successful therapeutic targets, such as RARA and RUNX1. This therapeutic strategy can be accelerated by characterizing new potential TF targets.

RESULTS

Two kinds of therapeutic signatures of TFs in A375 (skin) and HT29 (colon) cancer cells were characterized by analyzing TF activities under effective and ineffective compounds to cancer. First, the therapeutic TFs (TTs) were identified as the TFs that are significantly activated or repressed under effective compared to ineffective compounds. Second, the therapeutically correlated TF pairs (TCPs) were determined as the TF pairs whose activity correlations show substantial discrepancy between the effective and ineffective compounds. It was facilitated by incorporating (i)compound-induced gene expressions (LINCS), (ii) compound-induced cell viabilities (GDSC) and (iii) TF-target interactions (TRUST2). As a result, among 627 TFs, the 35 TTs (such as MYCN and TP53) and the 214 TCPs (such as FOXO3 and POU2F2 pair) were identified. The TTs and the proteins on the paths between TCPs were compared with the known therapeutic targets, tumor suppressors, oncogenes and CRISPR-Cas9 knockout screening, which yielded significant consequences. We expect that the results provide good candidates for therapeutic TF targets in cancer.

AVAILABILITY AND IMPLEMENTATION

The data and Python implementations are available at https://github.com/jmjung83/TT_and_TCP.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Stanniocalcin-2 promotes cell EMT and glycolysis via activating ITGB2/FAK/SOX6 signaling pathway in nasopharyngeal carcinoma

Stanniocalcin-2 (STC2) has been proved to regulate a variety of signaling pathways including cell growth, metastasis, and therapeutic resistance. However, the role of STC2 in the regulation of nasopharyngeal carcinoma (NPC) remains poorly understood. In this study, we investigated the regulatory function of STC2 on epithelial-mesenchymal transition (EMT) and glycolysis traits in NPC and revealed the underlying molecular mechanisms. We found that STC2 was highly expressed in primary nasopharyngeal carcinoma tissues and lymph node metastatic tissues. Silencing of STC2 inhibited cell proliferation, invasion, and glycolysis. Further analyses for the clinical samples demonstrated that STC2 expression was associated with the poor clinical progression. Moreover, we demonstrated the interaction of ITGB2 with STC2 and its involvement in STC2-mediated ITGB2/FAK/SOX6 axis. Collectively, our results provide new insights into understanding the regulatory mechanism of STC2 and suggest that the STC2/ITGB2/FAK/SOX6 signaling axis may be a potential therapeutic target for NPC.

The role of SOX family transcription factors in gastric cancer

Gastric cancer (GC) is a leading cause of death worldwide. GC is the third-most common cause of cancer-related death after lung and colorectal cancer. It is also the fifth-most commonly diagnosed cancer. Accumulating evidence has revealed the role of signaling networks in GC progression. Identification of these molecular pathways can provide new insight into therapeutic approaches for GC. Several molecular factors involved in GC can play both onco-suppressor and oncogene roles. Sex-determining region Y (Sry)-box-containing (SOX) family members are transcription factors with a well-known role in cancer. SOX proteins can bind to DNA to regulate cellular pathways via a highly conserved domain known as high mobility group (HMG). In the present review, the roles of SOX proteins in the progression and/or inhibition of GC are discussed. The dual role of SOX proteins as tumor-promoting and tumor-suppressing factors is highlighted. SOX members can affect upstream mediators (microRNAs, long non-coding RNAs and NF-κB) and down-stream mediators (FAK, HIF-1α, CDX2 and PTEN) in GC. The possible role of anti-tumor compounds to target SOX pathway members in GC therapy is described. Moreover, SOX proteins may be used as diagnostic or prognostic biomarkers in GC.

lncRNA PART1, manipulated by transcriptional factor FOXP2, suppresses proliferation and invasion in ESCC by regulating the miR‑18a‑5p/SOX6 signaling axis

An increasing number of studies have demonstrated that long non-coding (lnc)RNAs are associated with tumor invasion, metastasis and the prognosis of patients with a variety of different tumors. However, the roles of lncRNA prostate androgen regulated transcript 1 (PART1) in esophageal squamous cell carcinoma (ESCC) remain unknown. In the present study, reverse transcription-quantitative PCR was performed to investigate the levels of PART1, SRY-box transcription factor 6 (SOX6) and miR-18a-5p in ESCC tissues and cells. The functions of PART1 in ESCC were demonstrated using Cell Counting Kit-8 and Matrigel assays. Promoter activity and dual-luciferase reporter assays, RNA immunoprecipitation and western blot analyses were also used to determine the potential mechanisms of PART1 in ESCC cell lines. It was found that PART1 and SOX6 were both downregulated in ESCC tissues and cells, and their low expression levels were associated with TNM stage, lymph node metastasis and poor prognosis in patients with ESCC. Forkhead box protein P2 (FOXP2) exhibited low expression level in ESCC tissues, and its expression was positively correlated with PART1 expression level in ESCC tissues. FOXP2 was found to bind to the promoter region of PART1 to regulate its expression in ESCC cells. Functionally, PART1 overexpression suppressed cell proliferation and invasion, whereas PART1 downregulation promoted cell proliferation and invasion in the ESCC cell lines. Mechanistically, PART1 functions as a competing endogenous (ce)RNA by sponging miR-18a-5p, resulting in the upregulation of the downstream target gene, SOX6, coupled with the inactivation of the β-catenin/c-myc signaling axis, to suppress ESCC cell proliferation and invasion. In conclusion, data from the present study unveil a potential ceRNA regulatory pathway, in which PART1 affects SOX6 expression level by sponging miR-18a-5p, to ultimately suppress ESCC development and progression.

The Role of Noncoding RNAs in the Regulation of Anoikis and Anchorage-Independent Growth in Cancer

Cancer is a global health concern, and the prognosis of patients with cancer is associated with metastasis. Multistep processes are involved in cancer metastasis. Accumulating evidence has shown that cancer cells acquire the capacity of anoikis resistance and anchorage-independent cell growth, which are critical prerequisite features of metastatic cancer cells. Multiple cellular factors and events, such as apoptosis, survival factors, cell cycle, EMT, stemness, autophagy, and integrins influence the anoikis resistance and anchorage-independent cell growth in cancer. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are dysregulated in cancer. They regulate cellular signaling pathways and events, eventually contributing to cancer aggressiveness. This review presents the role of miRNAs and lncRNAs in modulating anoikis resistance and anchorage-independent cell growth. We also discuss the feasibility of ncRNA-based therapy and the natural features of ncRNAs that need to be contemplated for more beneficial therapeutic strategies against cancer.

Upregulation of miR-1269 Contributes to the Progression of Esophageal Squamous Cell Cancer Cells and Is Associated With Poor Prognosis

Background:

MicroRNA-1269 (miR-1269) has been identified upregulated in several cancers, as well as in esophageal cancer. In the present study, we investigated the clinical prognostic significance and potential functional role of miR-1269 in esophageal squamous cell carcinoma (ESCC).

Methods:

A total of 107 ESCC patients who underwent surgical resection were enrolled in this study. miR-1269 expression was measured using quantitative real-time PCR (qRT-PCR). Kaplan-Meier method and multivariate Cox regression analysis were used to explore the prognostic significance of miR-1269. CCK-8 assays and Transwell assays were used to investigate the effects of miR-1269 on cell proliferation, migration, and invasion. The direct association between miR-1269 and SOX6 was evaluated using a dual-luciferase reporter assay.

Results:

The expression of miR-1269 was significantly upregulated in ESCC tissues and cell lines compared with adjacent normal tissues and esophageal epithelial cell line, respectively. What’s more, the upregulation of miR-1269 was associated with positive lymph node metastasis and advanced TNM stage. ESCC patients with high miR-1269 expression had shorter overall survival than those with low miR-1269 expression levels. Compared with the control group, overexpression of miR-1269 promoted cell proliferation, migration, and invasion, while knockdown of miR-1269 inhibited cell proliferation, migration, and invasion. SOX6 was a direct target of miR-1269.

Conclusion:

These results suggest that miR-1269 plays an important role in the progression of ESCC by targeting SOX6 and may be a potential prognostic biomarker and the miR-1269/SOX6 axis may be a therapeutic target for the patient with ESCC.

microRNA-499a promotes the progression and chemoresistance of cervical cancer cells by targeting SOX6

Emerging evidence has indicated that microRNAs are involved in multiple processes of cancer development. Previous studies have demonstrated that microRNA-499a (miR-499a) plays both oncogenic and tumor suppressive roles in several types of malignancies, and genetic variants in miR-499a are associated with the risk of cervical cancer. However, the biological roles of miR-499a in cervical cancer have not been investigated. Quantitative real-time PCR was used to assess miR-499a expression in cervical cancer cells. Mimics or inhibitor of miR-499a was transfected into cervical cancer cells to upregulate or downregulate miR-499a expression. The effects of miR-499a expression change on cervical cancer cells proliferation, colony formation, tumorigenesis, chemosensitivity, transwell migration and invasion were assessed. The potential targets of miR-499a were predicted using online database tools and validated using real-time PCR, Western blot and luciferase reporter experiments. miR-499a was significantly upregulated in cervical cancer cells. Moreover, overexpression of miR-499a significantly enhanced the proliferation, cell cycle progression, colony formation, apoptosis resistance, migration and invasion of cervical cancer cells, while inhibiting miR-499a showed the opposite effects. Further exploration demonstrated that Sex-determining region Y box 6 was the direct target of miR-499a. miR-499a-induced SOX6 downregulation mediated the oncogenic effects of miR-499a in cervical cancer. Inhibiting miR-499a could enhance the anticancer effects of cisplatin in the xenograft mouse model of cervical cancer. Our findings for the first time suggest that miRNA-499a may play an important role in the development of cervical cancer and could serve as a potential therapeutic target.

S100A16 induces epithelial-mesenchymal transition in human PDAC cells and is a new therapeutic target for pancreatic cancer treatment that synergizes with gemcitabine

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, with a poor 5-year survival rate of approximately 6%, mostly due to poor treatment response and early progression. The S100 gene family participates in various pathophysiological processes in various malignancies. S100A16 is a member of the S100 family, which is abnormally expressed in PDAC; however, its biological functions and mechanisms of action remain unclear. We analysed the Gene Expression Omnibus (GEO) public database and the gene ChIP data collected in our previous study of human PDAC cell line PANC-1 cocultured with M2 macrophages to identify differentially expressed genes (DEGs). Twenty-three overexpressed genes were identified by screening. Then, the selected genes were analysed using The Cancer Genome Atlas (TCGA) database to assess whether they have significant impact on the overall survival (OS) of PDAC patients. Of the 14 DEGs identified, S100A16 was associated with poor prognosis and was selected for further investigation; the results indicate that S100A16 is positively correlated with epithelial-mesenchymal transition (EMT)-related genes in the TCGA dataset. Subsequent in vitro and in vivo experiments demonstrated that S100A16 induces the EMT to promote the metastasis of human PDAC cells and that the effect is mediated by the enhanced expression of TWIST1 and activation of the STAT3 signalling pathway. The antitumour effect of gemcitabine (GEM) was enhanced in combination with S100A16 downregulation. In conclusion, our findings suggest that S100A16 is a novel potential therapeutic target for human PDAC treatment.

Inhibition of lncRNA MAAT Controls Multiple Types of Muscle Atrophy by cis- and trans-Regulatory Actions

Muscle atrophy is associated with negative outcomes in a variety of diseases. Identification of a common therapeutic target would address a significant unmet clinical need. Here, we identify a long non-coding RNA (lncRNA) (muscle-atrophy-associated transcript, lncMAAT) as a common regulator of skeletal muscle atrophy. lncMAAT is downregulated in multiple types of muscle-atrophy models both in vivo (denervation, Angiotensin II [AngII], fasting, immobilization, and aging-induced muscle atrophy) and in vitro (AngII, H₂O₂, and tumor necrosis factor alpha [TNF-α]-induced muscle atrophy). Gain- and loss-of-function analysis both in vitro and in vivo reveals that downregulation of lncMAAT is sufficient to induce muscle atrophy, while overexpression of lncMAAT can ameliorate multiple types of muscle atrophy. Mechanistically, lncMAAT negatively regulates the transcription of miR-29b through SOX6 by a trans-regulatory module and increases the expression of the neighboring gene Mbnl1 by a cis-regulatory module. Therefore, overexpression of lncMAAT may represent a promising therapy for muscle atrophy induced by different stimuli.

SOX6 represses tumor growth of clear cell renal cell carcinoma by HMG domain-dependent regulation of Wnt/β-catenin signaling

Sex-determining region Y box (SOXs) are expressed in various cells and control cell fate and differentiation in a multitude of physiologic processes. SOX6, a main representative of SOXs, is involved in the regulation of carcinogenesis in various human malignancies. However, the role of SOX6 in clear cell renal cell carcinoma (ccRCC) remains unclear. In this study, SOX6 expression in ccRCC and its clinical significance were investigated. In vitro and in vivo assays were used to explore the tumor-related function and the underlying molecular mechanism of SOX6 in ccRCC. We confirmed that SOX6 was frequently downregulated in ccRCC tissues and cell lines. Besides, downregulation of SOX6 was significantly associated with larger tumor sizes, advanced tumor stage, higher Fuhrman grades, and its expression could act as an independent prognostic factor for ccRCC (hazards ratio = 0.590, P = .026). Gain/loss-of-function experiments demonstrated that SOX6 could remarkably inhibit tumor cell growth and foci formation in vitro and xenograft tumorigenesis in vivo, respectively. Mechanistically, SOX6 could influence cell cycle by regulating the G1/the S phase transition and had an inhibitory effect on Wnt/β-catenin signaling as well as its target genes, c-Myc and cyclin D1. Interesting, the tumor-suppressive function of SOX6 was proved to be dependent on its specific high-mobility-group (HMG) domain. In general, our findings indicated that SOX6 was a novel tumor suppressor and prognostic biomarker in ccRCC. SOX6 could inhibit tumor growth by negatively regulating the Wnt/β-catenin signaling pathway in an HMG domain-dependent manner in ccRCC, which might provide a novel therapeutic approach for ccRCC.

SOX9 Is Essential for Triple-Negative Breast Cancer Cell Survival and Metastasis

Triple-negative breast cancer (TNBC) has the worst prognosis of all breast cancers, and lacks effective targeted treatment strategies. Previously, we identified 33 transcription factors highly expressed in TNBC. Here, we focused on six sex determining region Y-related HMG-box (SOX) transcription factors (SOX4, 6, 8, 9, 10, and 11) highly expressed in TNBCs. Our siRNA screening assay demonstrated that SOX9 knockdown suppressed TNBC cell growth and invasion in vitro. Thus, we hypothesized that SOX9 is an important regulator of breast cancer survival and metastasis, and demonstrated that knockout of SOX9 reduced breast tumor growth and lung metastasis in vivo. In addition, we found that loss of SOX9 induced profound apoptosis, with only a slight impairment of G₁ to S progression within the cell cycle, and that SOX9 directly regulates genes controlling apoptosis. On the basis of published CHIP-seq data, we demonstrated that SOX9 binds to the promoter of apoptosis-regulating genes (tnfrsf1b, fadd, tnfrsf10a, tnfrsf10b, and ripk1), and represses their expression. SOX9 knockdown upregulates these genes, consistent with the induction of apoptosis. Analysis of available CHIP-seq data showed that SOX9 binds to the promoters of several epithelial-mesenchymal transition (EMT)- and metastasis-regulating genes. Using CHIP assays, we demonstrated that SOX9 directly binds the promoters of genes involved in EMT (vim, cldn1, ctnnb1, and zeb1) and that SOX9 knockdown suppresses the expression of these genes. IMPLICATIONS: Our studies identified the SOX9 protein as a "master regulator" of breast cancer cell survival and metastasis, and provide preclinical rationale to develop SOX9 inhibitors for the treatment of women with metastatic triple-negative breast cancer.

SOX6 suppresses the development of lung adenocarcinoma by regulating expression of p53, p21CIPI , cyclin D1 and β-catenin

The Sry‐related high‐mobility group box6 (SOX6) has been implicated in the development of cancer, but its role in lung cancer is incompletely understood. Here, we report that SOX6 expression is frequently down‐regulated in lung adenocarcinoma tissues. Moreover, SOX6 can inhibit the proliferation and invasion of lung adenocarcinoma cells, which may occur through cell cycle arrest at G1/S due to up‐regulation of p53 and p21^CIPI and down‐regulation of cyclin D1 and β‐catenin. Univariate and multivariate analyses revealed that the expression of SOX6 is significantly associated with patient disease‐related survival and is an independent prognostic factor for lung adenocarcinoma. These data suggest that SOX6 may act as a suppressor of lung adenocarcinoma.

The Epithelial-to-Mesenchymal Transition (EMT) in Development and Cancer

Epithelial-to-mesenchymal transitions (EMTs) are complex cellular processes where cells undergo dramatic changes in signaling, transcriptional programming, and cell shape, while directing the exit of cells from the epithelium and promoting migratory properties of the resulting mesenchyme. EMTs are essential for morphogenesis during development and are also a critical step in cancer progression and metastasis formation. Here we provide an overview of the molecular regulation of the EMT process during embryo development, focusing on chick and mouse gastrulation and neural crest development. We go on to describe how EMT regulators participate in the progression of pancreatic and breast cancer in mouse models, and discuss the parallels with developmental EMTs and how these help to understand cancer EMTs. We also highlight the differences between EMTs in tumor and in development to arrive at a broader view of cancer EMT. We conclude by discussing how further advances in the field will rely on in vivo dynamic imaging of the cellular events of EMT.

miRNA‑342 suppresses renal interstitial fibrosis in diabetic nephropathy by targeting SOX6

Diabetic kidney disease (DKD) is one of the major microvascular complications in patients with type 1 and/or type 2 diabetes, the first cause of end-stage renal disease (ESRD) in several countries and regions. However, the pathogenesis of DKD and the mechanisms through which it leads to ESRD remain unknown. Thus, in this study, we aimed to elucidate some of these mechanisms. The expression of microRNA (miRNA or miR)-342-3p and SRY-box 6 (SOX6) in the renal tissues of mice with DKD and mouse renal mesangial cells (MCs) was determined by RT-qPCR and western blot analysis. The diabetic kidney environment was established using high-glucose medium. SOX6 was verified as a target gene of miR-342-3p by dual-luciferase activity assay. In addition, western blot analysis was employed to determine the changes in the levels of several biomarkers of fibrosis [transforming growth factor (TGF)-β1, fibronectin (FN), collagen IV (referred to as C-IV) and phosphatase and tensin homolog (PTEN)]. Compared with THE control mice, the expression of miR-342-3p in the kidney tissues of mice with DKD was down-regulated, whereas that of SOX6 was upregulated. The same phenomenon was observed in the MCs cultured in high-glucose medium. Subsequently, miR-342-3p inhibited SOX6 expression, promoted cell proliferation and inhibited the apoptosis of MCs. Moreover, the overexpression of miR-342-3p suppressed high glucose-induced renal interstitial fibrosis. In addition, it was found that miR-342-3p inhibited SOX6 expression by binding to the 3′-UTR of SOX6. On the whole, the findings of this study demonstrate that miR-342-3p suppresses the progression of DKD by inducing the degradation of SOX6. Thus, the miR-342-3p/SOX6 axis may serve as a novel therapeutic target in the treatment of DKD.

MicroRNA-765 is pregulated in multiple myeloma and serves an oncogenic role by directly targeting SOX6

Increasing evidence has revealed that microRNAs (miRNAs) are closely associated with multiple myeloma (MM) pathogenesis and progression. Therefore, an in-depth understanding of the biological functions of miRNAs in MM may be helpful for the identification of promising therapeutic techniques for patients with MM. miRNA-765 (miR-765) has been reported to be dysregulated in many types of human cancer. However, the expression pattern, specific roles and underlying mechanisms of miR-765 in MM remain largely unknown. In the present study, plasma miR-765 significantly increased in patients with MM and cell lines. The downregulation of miR-765 in MM cells attenuated proliferation and promoted apoptosis. Bioinformatics analysis predicted that SRY-Box 6 (SOX6) was a putative target of miR-765. This was experimentally verified using a luciferase reporter assay, reverse transcription-quantitative PCR and western blot analysis. Furthermore, plasma SOX6 was downregulated in patients with MM and the downregulation of SOX6 was inversely correlated with that of miR-765 expression. Furthermore, SOX6 knockdown markedly abrogated the effects of miR-765 underexpression on cell proliferation and apoptosis in MM. The current study demonstrated that miR-765 serves an oncogenic role in MM progression by directly targeting SOX6, suggesting that miR-765 may be a potential therapeutic target for MM prevention and treatment.

SOX6 blocks the proliferation of BCR-ABL1+ and JAK2V617F+ leukemic cells

SOX6 is a HMG-box transcription factor expressed in a wide range of tissues. Recent data show that SOX6 expression is altered in different cancers, in the majority of cases being downregulated. To date, no data are available about SOX6 role in hematological malignancies. Here we demonstrate that SOX6 overexpressing BCR-ABL1⁺ B-ALL cells are unable to promote leukemia in a mouse model. Starting from this observation, we extended our study to a panel of human leukemic cells carrying genetic lesions distinctive of different types of leukemias and myeloproliferative disorders (the BCR-ABL1 translocation and the JAK2V617F amino acid substitution) to dissect the cellular events induced by SOX6. The inhibition of proliferation is the invariant outcome of SOX6 overexpression but it is achieved via two different cellular responses: terminal differentiation in erythroid-biased cells, irrespectively of their mutation, and apoptosis in megakaryocytic-primed and lymphoid cells. Within this context, cells carrying the highest copy number of the JAK2V617F allele better counteract the SOX6-imposed growth arrest. The interrogation of the GEPIA (Gene Expression Profiling Interactive Analysis) human dataset reveals that SOX6 is downregulated in a cohort of AML patients, uncovering a wide anti-proliferative role of SOX6 in a variety of mutant backgrounds.

UBE2S mediates tumor progression via SOX6/β-Catenin signaling in endometrial cancer

Dysregulation of ubiquitin-conjugating enzyme E2S (UBE2S) contributes to tumor progression. However, its clinical significance and biological function in endometrial cancer (EMC) remain unclear. Here, we show that UBE2S is upregulated in EMC and exhibits oncogenic activities via activation of SOX6/β-Catenin signaling. High expression of UBE2S is significantly associated with poor prognosis in two independent cohorts consisting of a total of 773 patients with EMC. in vitro studies demonstrate that ectopic expression of UBE2S promotes cell proliferation and migration, whereas knockdown of UBE2S results in opposite phenotypes. Overexpression of UBE2S in EMC cells enhances the nuclear translocation of β-Catenin, and subsequently induces the expression of c-Myc and Cyclin D1. Inhibition of β-Catenin by XAV-939 markedly attenuates UBE2S-promoted cell growth. Mechanistically, UBE2S suppresses the expression of SOX6 to trigger β-Catenin signaling. Re-expression of SOX6 in UBE2S-expressing EMC cells abolishes the nuclear localization of β-Catenin. Collectively, these data suggest UBE2S may serve as a promising prognostic factor and function as an oncogene in EMC. The newly identified UBE2S/SOX6/β-Catenin axis represents a new potential therapeutic target for EMC intervention.

microRNA-181b suppresses the metastasis of lung cancer cells by targeting sex determining region Y-related high mobility group-box 6 (Sox6)

BACKGROUND

The aim of the study was to measure the expression of microRNA (miR)-181b in patients with lung cancer, investigate its biological function and elucidate the underlying mechanisms associated with the development of lung cancer.

METHODS

miR-181b expression in tissues was measured via RT-qPCR. After A549 cells were transfected with miR-181b mimic or si-Sox6, the proliferation, migration and cell cycle distribution of A549 were evaluated using cell counting kit-8 assay, transwell assay and flow cytometry. The levels of cell cycle-related proteins and Sox6 were analyzed by western blotting. Gene targets of miR-181b were predicted via bioinformatics analysis and verified using a dual-luciferase reporter gene assay.

RESULTS

Expression of miR-181b was significantly downregulated in lung cancer tissues (P < 0.05), and was inversely correlated with the degree of cell differentiation and clinical stages of lung cancer (both P < 0.05). Additionally, the expression of miR-181b was significantly lower in adenocarcinoma compared with squamous cell carcinoma in the lungs (P < 0.05). Overexpression of miR-181b significantly decreased the protein level of Sox6 and significantly suppressed the cell proliferation and metastasis (both P < 0.05); this effect was also observed in A549 cells transfected with si-Sox6. The luciferase activity of a Sox6 3'-untranslated region-based reporter construct was significantly lower when transfected with miR-181b (P < 0.05), which suggests that Sox6 is a direct target of miR-181b.

CONCLUSION

The results of the present study suggest that miR-181b may function as a tumor inhibitor in the development of lung cancer via targeting Sox6 to decrease the proliferation and metastasis of lung cancer cells.