SOX9: The master regulator of cell fate in breast cancer

Diverse functions of SOX9 in liver development and homeostasis and hepatobiliary diseases

The liver is the central organ for digestion and detoxification and has unique metabolic and regenerative capacities. The hepatobiliary system originates from the foregut endoderm, in which cells undergo multiple events of cell proliferation, migration, and differentiation to form the liver parenchyma and ductal system under the hierarchical regulation of transcription factors. Studies on liver development and diseases have revealed that SRY-related high-mobility group box 9 (SOX9) plays an important role in liver embryogenesis and the progression of hepatobiliary diseases. SOX9 is not only a master regulator of cell fate determination and tissue morphogenesis, but also regulates various biological features of cancer, including cancer stemness, invasion, and drug resistance, making SOX9 a potential biomarker for tumor prognosis and progression. This review systematically summarizes the latest findings of SOX9 in hepatobiliary development, homeostasis, and disease. We also highlight the value of SOX9 as a novel biomarker and potential target for the clinical treatment of major liver diseases.

miR-192 family in breast cancer: Regulatory mechanisms and diagnostic value

There is a growing interest in the role of the miRNA family in human cancer. The miRNA-192 family is a group of conserved small RNAs, including miR-192, miR-194, and miR-215. Recent studies have shown that the incidence and mortality of breast cancer have been increasing epidemiologically year by year, and it is urgent to clarify the pathogenesis of breast cancer and seek new diagnostic and therapeutic methods. There is increasing evidence that miR-192 family members may be involved in the occurrence and development of breast cancer. This review describes the regulatory mechanism of the miRNA-192 family affecting the malignant behavior of breast cancer cells and evaluates the value of the miRNA-192 family as a diagnostic and prognostic biomarker for breast cancer. It is expected that summarizing and discussing the relationship between miRNA-192 family members and breast cancer, it will provide a new direction for the clinical diagnosis and treatment of breast cancer and basic medical research.

E3 ubiquitin ligase BCA2 promotes breast cancer stemness by up-regulation of SOX9 by LPS

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Breast cancer stem cells (BCSCs) are believed to play a crucial role in the carcinogenesis, therapy resistance, and metastasis of TNBC. It is well known that inflammation promotes stemness. Several studies have identified breast cancer-associated gene 2 (BCA2) as a potential risk factor for breast cancer incidence and prognosis. However, whether and how BCA2 promotes BCSCs has not been elucidated. Here, we demonstrated that BCA2 specifically promotes lipopolysaccharide (LPS)-induced BCSCs through LPS induced SOX9 expression. BCA2 enhances the interaction between myeloid differentiation primary response protein 88 (MyD88) and Toll-like receptor 4 (TLR4) and inhibits the interaction of MyD88 with deubiquitinase OTUD4 in the LPS-mediated NF-κB signaling pathway. And SOX9, an NF-κB target gene, mediates BCA2's pro-stemness function in TNBC. Our findings provide new insights into the molecular mechanisms by which BCA2 promotes breast cancer and potential therapeutic targets for the treatment of breast cancer.

Stable and Oscillatory Hypoxia Differentially Regulate Invasibility of Breast Cancer Associated Fibroblasts

As local regions in the tumor outstrip their oxygen supply, hypoxia can develop, affecting not only the cancer cells, but also other cells in the microenvironment, including cancer associated fibroblasts (CAFs). Hypoxia is also not necessarily stable over time, and can fluctuate or oscillate. Hypoxia Inducible Factor-1 is the master regulator of cellular response to hypoxia, and can also exhibit oscillations in its activity. To understand how stable, and fluctuating hypoxia influence breast CAFs, we measured changes in gene expression in CAFs in normoxia, hypoxia, and oscillatory hypoxia, as well as measured change in their capacity to resist, or assist breast cancer invasion. We show that hypoxia has a profound effect on breast CAFs causing activation of key pathways associated with fibroblast activation, but reduce myofibroblast activation and traction force generation. We also found that oscillatory hypoxia, while expectedly resulted in a "sub-hypoxic" response in gene expression, it resulted in specific activation of pathways associated with actin polymerization and actomyosin maturation. Using traction force microscopy, and a nanopatterned stromal invasion assay, we show that oscillatory hypoxia increases contractile force generation vs stable hypoxia, and increases heterogeneity in force generation response, while also additively enhancing invasibility of CAFs to MDA-MB-231 invasion. Our data show that stable and unstable hypoxia can regulate many mechnobiological characteristics of CAFs, and can contribute to transformation of CAFs to assist cancer dissemination and onset of metastasis.

Functional analysis of a down-regulated transcription factor-SoxNeuroA gene involved in the acaricidal mechanism of scopoletin against spider mites

BACKGROUND

Insight into the mode of action of plant-derived acaricides will help in the development of sustainable control strategies for mite pests. Scopoletin, a promising plant-derived bioactive compound, displays prominent acaricidal activity against Tetranychus cinnabarinus. The transcription factor SoxNeuroA plays a vital role in maintaining calcium ion (Ca2+ ) homeostasis. Down-regulation of SoxNeuroA gene expression occurs in scopoletin-exposed mites, but the functional role of this gene remains unknown.

RESULTS

A SoxNeuroA gene from T. cinnabarinus (TcSoxNeuroA) was first cloned and identified. Reverse transcription polymerase chain reaction (RT-PCR), quantitative real-time polymerase chain reaction (qPCR), and Western blotting assays all confirmed that the gene expression and protein levels of TcSoxNeuroA were significantly reduced under scopoletin exposure. Furthermore, RNA interference silencing of the weakly expressed SoxNeuroA gene significantly enhanced the susceptibility of mites to scopoletin, suggesting that the acaricidal mechanism of scopoletin was mediated by the weakly expressed SoxNeuroA gene. Additionally, yeast one-hybrid (Y1H) and dual-luciferase reporter assays revealed that TcSoxNeuroA was a repressor of Orai1 Ca2+ channel gene transcription, and the key binding sequence was ATCAAAG (positions -361 to -368 of the Orai1 promoter). Importantly, site-directed mutagenesis and microscale thermophoresis assays further indicated that ASP185, ARG189, and LYS217, which were key predicted hydrogen-bonding sites in the molecular docking model, may be the vital binding sites for scopoletin in TcSoxNeuroA.

CONCLUSION

These results demonstrate that the acaricidal mechanism of scopoletin involves inhibition of the transcription factor SoxNeuroA, thus inducing the activation of the Orai1 Ca2+ channel, eventually leading to Ca2+ overload and lethality. Elucidation of the transcription factor-targeted mechanism for this potent plant-derived acaricide has vital implications for the design of next-generation green acaricides with novel targets. © 2023 Society of Chemical Industry.

Mechanisms and functions of SUMOylation in health and disease: a review focusing on immune cells

SUMOylation, which is a type of post-translational modification that involves covalent conjugation of small ubiquitin-like modifier (SUMO) proteins to target substrates, regulates various important molecular and cellular processes, including transcription, the cell cycle, cell signaling, and DNA synthesis and repair. Newly synthesized SUMO is immature and cleaved by the SUMO-specific protease family, resulting in exposure of the C-terminal Gly-Gly motif to become the mature form. In the presence of ATP, mature SUMO is conjugated with the activating enzyme E1 through the cysteine residue of E1, followed by transfer to the cysteine residue of E2-conjugating enzyme Ubc9 in humans that recognizes and modifies the lysine residue of a substrate protein. E3 SUMO ligases promote SUMOylation. SUMOylation is a reversible modification and mediated by SUMO-specific proteases. Cumulative studies have indicated that SUMOylation affects the functions of protein substrates in various manners, including cellular localization and protein stability. Gene knockout studies in mice have revealed that several SUMO cycling machinery proteins are crucial for the development and differentiation of various cell lineages, including immune cells. Aberrant SUMOylation has been implicated in several types of diseases, including cancers, cardiovascular diseases, and autoimmune diseases. This review summarizes the biochemistry of SUMO modification and the general biological functions of proteins involved in SUMOylation. In particular, this review focuses on the molecular mechanisms by which SUMOylation regulates the development, maturation, and functions of immune cells, including T, B, dendritic, and myeloid cells. This review also discusses the underlying relevance of disruption of SUMO cycling and site-specific interruption of SUMOylation on target proteins in immune cells in diseases, including cancers and infectious diseases.

HuR (ELAVL1) Stabilizes SOX9 mRNA and Promotes Migration and Invasion in Breast Cancer Cells

RNA-binding proteins play diverse roles in cancer, influencing various facets of the disease, including proliferation, apoptosis, angiogenesis, senescence, invasion, epithelial-mesenchymal transition (EMT), and metastasis. HuR, a known RBP, is recognized for stabilizing mRNAs containing AU-rich elements (AREs), although its complete repertoire of mRNA targets remains undefined. Through a bioinformatics analysis of the gene expression profile of the Hs578T basal-like triple-negative breast cancer cell line with silenced HuR, we have identified SOX9 as a potential HuR-regulated target. SOX9 is a transcription factor involved in promoting EMT, metastasis, survival, and the maintenance of cancer stem cells (CSCs) in triple-negative breast cancer. Ribonucleoprotein immunoprecipitation assays confirm a direct interaction between HuR and SOX9 mRNA. The half-life of SOX9 mRNA and the levels of SOX9 protein decreased in cells lacking HuR. Cells silenced for HuR exhibit reduced migration and invasion compared to control cells, a phenotype similar to that described for SOX9-silenced cells.

SOX9 promotes the invasion and migration of lung adenocarcinoma cells by activating the RAP1 signaling pathway

OBJECTIVE

SOX9 has been shown to be related to the metastasis of various cancers. Recently, it has been reported that SOX9 plays a regulatory role in lung adenocarcinoma (LUAD) cell metastasis, but the specific mechanism remains to be explored. Therefore, the objective of this study was to observe the effect and mechanism of SOX9 on the invasion and migration of LUAD cells.

METHODS

RT-qPCR was applied to observe the expression of SOX9 and RAP1 in tumor tissues and corresponding normal lung tissues collected from LUAD patients. Co-immunoprecipitation and Pearson correlation to analyze the expression correlation of SOX9 with RAP1. To observe the role of SOX9, the invasion and migration levels of LUAD A549 cells in each group were observed by Transwell invasion assay and Scratch migration assay after knocking down or overexpressing SOX9. Besides, the expression levels of RAP1 pathway-related proteins (RAP1, RAP1GAP and RasGRP33) were observed by RT-qCPR or western blot. Subsequently, RAP1 was overexpressed and SOX9 was knocked down in A549 cells, and then the cell invasion/migration level and RAP1 pathway activity were assessed.

RESULTS

The expression levels of SOX9 and RAP1 in tumor tissues and A549 cells of LUAD patients were significantly increased and positively correlated. Overexpression of SOX9 or RAP1 alone in A549 cells enhanced the invasion and migration ability of cells, as well as up-regulated the expression levels of RAP1, RAP1GAP and RasGRP33. However, knocking down SOX9 decreased cell invasion and migration levels and weakened the activity of RAP1 pathway. Notably, overexpressing RAP1 while knocking down SOX9 significantly activated RAP1 pathway and promoted cell invasion and migration.

CONCLUSION

Overexpression of SOX9 in LUAD can significantly activate the RAP1 signaling pathway and promote cell invasion and migration.

Comprehensive single cell aging atlas of mammary tissues reveals shared epigenomic and transcriptomic signatures of aging and cancer

Aging is the greatest risk factor for breast cancer; however, how age-related cellular and molecular events impact cancer initiation is unknown. We investigate how aging rewires transcriptomic and epigenomic programs of mouse mammary glands at single cell resolution, yielding a comprehensive resource for aging and cancer biology. Aged epithelial cells exhibit epigenetic and transcriptional changes in metabolic, pro-inflammatory, or cancer-associated genes. Aged stromal cells downregulate fibroblast marker genes and upregulate markers of senescence and cancer-associated fibroblasts. Among immune cells, distinct T cell subsets (Gzmk+, memory CD4+, γδ) and M2-like macrophages expand with age. Spatial transcriptomics reveal co-localization of aged immune and epithelial cells in situ. Lastly, transcriptional signatures of aging mammary cells are found in human breast tumors, suggesting mechanistic links between aging and cancer. Together, these data uncover that epithelial, immune, and stromal cells shift in proportions and cell identity, potentially impacting cell plasticity, aged microenvironment, and neoplasia risk.

Single-cell transcriptome profiling reveals immune and stromal cell heterogeneity in primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a complex autoimmune disease characterized by lymphocytic infiltration and exocrine dysfunction, particularly affecting the salivary gland (SG). We employed single-cell RNA sequencing to investigate cellular heterogeneity in 11 patients with pSS and 5 non-SS controls. Notably, patients with pSS exhibited downregulated SOX9 in myoepithelial cells, potentially associated with impaired epithelial regeneration. An expanded ACKR1+ endothelial subpopulation in patients with pSS suggested a role in facilitating lymphocyte transendothelial migration. Our analysis of immune cells revealed expanded IGHD+ naive B cells in peripheral blood from patients with pSS. Pseudotime trajectory analysis outlined a bifurcated differentiation pathway for peripheral B cells, enriching three subtypes (VPREB3+ B, BANK1+ B, CD83+ B cells) within SGs in patients with pSS. Fibroblasts emerged as pivotal components in a stromal-immune interaction network, potentially driving extracellular matrix disruption, epithelial regeneration impairment, and inflammation. Our study illuminates immune and stromal cell heterogeneity in patients with pSS, offering insights into therapeutic strategies.

Cross-regulation between SOX9 and the canonical Wnt signalling pathway in stem cells

SOX9, a member of the SRY-related HMG-box transcription factors, has been reported to critically regulate fetal development and stem cell homeostasis. Wnt signalling is a highly conserved signalling pathway that controls stem cell fate decision and stemness maintenance throughout embryonic development and adult life. Many studies have shown that the interactions between SOX9 and the canonical Wnt signalling pathway are involved in many of the physiological and pathological processes of stem cells, including organ development, the proliferation, differentiation and stemness maintenance of stem cells, and tumorigenesis. In this review, we summarize the already-known molecular mechanism of cross-interactions between SOX9 and the canonical Wnt signalling pathway, outline its regulatory effects on the maintenance of homeostasis in different types of stem cells, and explore its potential in translational stem cell therapy.

MicroRNA-5195-3p mediated malignant biological behaviour of insulin-resistant liver cancer cells via SOX9 and TPM4

BACKGROUND

Primary liver cancer is a malignant tumour of the digestive system, ranking second in cancer mortality in China. In different types of cancer, such as liver cancer, microRNAs (miRNAs) have been shown to be dysregulated. However, little is known about the role of miR-5195-3p in insulin-resistant liver cancer.

METHODS AND RESULTS

In this study, in vitro and in vivo experiments were conducted to identify the altered biological behaviour of insulin-resistant hepatoma cells (HepG2/IR), and we proved that HepG2/IR cells had stronger malignant biological behaviour. Functional experiments showed that enhanced expression of miR-5195-3p could inhibit the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) and chemoresistance of HepG2/IR cells, while impaired expression of miR-5195-3p in HepG2 cells resulted in the opposite effects. Bioinformatics prediction and dual luciferase reporter gene assays proved that SOX9 and TPM4 were the target genes of miR-5195-3p in hepatoma cells.

CONCLUSIONS

In conclusion, our study demonstrated that miR-5195-3p plays a critical role in insulin-resistant hepatoma cells and might be a potential therapeutic target for liver cancer.

Interactions between genes altered during cardiotoxicity and neurotoxicity in zebrafish revealed using induced network modules analysis

As the manufacturing and development of new synthetic compounds increase to keep pace with the expanding global demand, adverse health effects due to these compounds are emerging as critical public health concerns. Zebrafish have become a prominent model organism to study toxicology due to their genomic similarity to humans, optical clarity, well-defined developmental stages, short generation time, and cost-effective maintenance. It also provides a shorter time frame for in vivo toxicology evaluation compared to the mammalian experimental systems. Here, we used meta-analysis to examine the alteration in genes during cardiotoxicity and neurotoxicity in zebrafish, caused by chemical exposure of any kind. First, we searched the literature comprehensively for genes that are altered during neurotoxicity and cardiotoxicity followed by meta-analysis using ConsensusPathDB. Since constant communication between the heart and the brain is an important physiological phenomenon, we also analyzed interactions among genes altered simultaneously during cardiotoxicity and neurotoxicity using induced network modules analysis in ConsensusPathDB. We observed inflammation and regeneration as the major pathways involved in cardiotoxicity and neurotoxicity. A large number of intermediate genes and input genes anchored in these pathways are molecular regulators of cell cycle progression and cell death and are implicated in tumor manifestation. We propose potential predictive biomarkers for neurotoxicity and cardiotoxicity and the major pathways potentially implicated in the manifestation of a particular toxicity phenotype.

TLE3 Sustains Luminal Breast Cancer Lineage Fidelity to Suppress Metastasis

Breast cancer subtypes and their phenotypes parallel different stages of the mammary epithelial cell developmental hierarchy. Discovering mechanisms that control lineage identity could provide novel avenues for mitigating disease progression. Here we report that the transcriptional corepressor TLE3 is a guardian of luminal cell fate in breast cancer and operates independently of the estrogen receptor. In luminal breast cancer, TLE3 actively repressed the gene-expression signature associated with highly aggressive basal-like breast cancers (BLBC). Moreover, maintenance of the luminal lineage depended on the appropriate localization of TLE3 to its transcriptional targets, a process mediated by interactions with FOXA1. By repressing genes that drive BLBC phenotypes, including SOX9 and TGFβ2, TLE3 prevented the acquisition of a hybrid epithelial-mesenchymal state and reduced metastatic capacity and aggressive cellular behaviors. These results establish TLE3 as an essential transcriptional repressor that sustains the more differentiated and less metastatic nature of luminal breast cancers. Approaches to induce TLE3 expression could promote the acquisition of less aggressive, more treatable disease states to extend patient survival.

SIGNIFICANCE

Transcriptional corepressor TLE3 actively suppresses SOX9 and TGFβ transcriptional programs to sustain the luminal lineage identity of breast cancer cells and to inhibit metastatic progression.

Rac1 promotes the reprogramming of glucose metabolism and the growth of colon cancer cells through upregulating SOX9

Metabolic reprogramming is the survival rule of tumor cells, and tumor cells can meet their high metabolic requirements by changing the energy metabolism mode. Metabolic reprogramming of tumor cells is an important biochemical basis of tumor malignant phenotypes. Ras-related C3 botulinum toxin substrate 1 (Rac1) is abnormally expressed in a variety of tumors and plays an important role in the proliferation, invasion, and migration of tumor cells. However, the role of Rac1 in tumor metabolic reprogramming is still unclear. Herein, we revealed that Rac1 was highly expressed in colon cancer tissues and cell lines. Rac1 promotes the proliferation, migration, and invasion of colon cancer cells by upregulating SOX9, which as a transcription factor can directly bind to the promoters of HK2 and G6PD genes and regulate their transcriptional activity. Rac1 upregulates the expression of SOX9 through the PI3K/AKT signaling pathway. Moreover, Rac1 can promote glycolysis and the activation of the pentose phosphate pathway in colon cancer cells by mediating the axis of SOX9/HK2/G6PD. These findings reveal novel regulatory axes involving Rac1/SOX9/HK2/G6PD in the development and progression of colon cancer, providing novel promising therapeutic targets.

To be or not to be: The double-edged sword roles of liver progenitor cells

Given the liver's remarkable and unique regenerative capacity, researchers have long focused on liver progenitor cells (LPCs) and liver cancer stem cells (LCSCs). LPCs can differentiate into both hepatocytes and cholangiocytes. However, the mechanism underlying cell conversion and its distinct contribution to liver homeostasis and tumorigenesis remain unclear. In this review, we discuss the complicated conversions involving LPCs and LCSCs. As the critical intermediate state in malignant transformation, LPCs play double-edged sword roles. LPCs are not only involved in hepatic wound-healing responses by supplementing liver cells and bile duct cells in the damaged liver but may transform into LCSCs under dysregulation of key signaling pathways, resulting in refractory malignant liver tumors. Because LPC lineages are temporally and spatially dynamic, we discuss crucial LPC subgroups and summarize regulatory factors correlating with the trajectories of LPCs and LCSCs in the liver tumor microenvironment. This review elaborates on the double-edged sword roles of LPCs to help understand the liver's regenerative potential and tumor heterogeneity. Understanding the sources and transformations of LPCs is essential in determining how to exploit their regenerative capacity in the future.

EGR1 Promotes Ovarian Hyperstimulation Syndrome Through Upregulation of SOX9 Expression

Angiogenesis is strongly associated with ovarian hyperstimulation syndrome (OHSS) progression. Early growth response protein 1 (EGR1) plays an important role in angiogenesis. This study aimed to investigate the function and mechanism of EGR1 involved in OHSS progression. RNA-sequencing was used to identify differentially expressed genes. In vitro OHSS cell model was induced by treating KGN cells with human chorionic gonadotropin (hCG). In vivo OHSS model was established in mice. The expression levels of EGR1, SOX1, and VEGF were determined by Quantitative Real-Time polymerase chain reaction (qRT-PCR), Western blot, immunofluorescence staining, and immunochemistry assay. The content of VEGF in the culture medium of human granulosa-like tumor cell line (KGN) cells was accessed by the ELISA assay. The regulatory effect of EGR1 on SRY-box transcription factor 9 (SOX9) was addressed by luciferase reporter assay and chromatin immunoprecipitation. The ERG1 and SOX9 levels were significantly upregulated in granulosa cells from OHSS patients and there was a positive association between EGR1 and SOX9 expression. In the ovarian tissues of OHSS mice, the levels of EGR1 and SOX9 were also remarkedly increased. Treatment with hCG elevated the levels of vascular endothelial growth factor (VEGF), EGR1, and SOX9 in KGN cells. Silencing of EGR1 reversed the promoting effect of hCG on VEGF and SOX9 expression in KGN cells. EGR1 transcriptionally regulated SOX9 expression through binding to its promoter. In addition, administration of dopamine decreased hCG-induced VEGF in KGN cells and ameliorated the progression of OHSS in mice, which were companied with decreased EGR1 and SOX9 expression. EGR1 has a promoting effect on OHSS progression and dopamine protects against OHSS through suppression of EGR1/SOX9 cascade. Our findings may provide new targets for the treatment of OHSS.

Comprehensive analysis, immune, and cordycepin regulation for SOX9 expression in pan-cancers and the matched healthy tissues

SRY-box transcription factor 9 (SOX9) (OMIM 608160) is a transcription factor. The expression of SOX9 in pan-cancers and the regulation by small molecules in cancer cell lines are unclear. In the current study, we comprehensively analyzed the expression of SOX9 in normal tissues, tumor tissues and their matched healthy tissues in pan-cancers. The study examined the correlation between immunomodulators and immune cell infiltrations in normal and tumor tissues. Cordycepin (CD), an adenosine analog for SOX9 expression regulation, was also conducted on cancer cells. The results found that SOX9 protein is expressed in a variety of organs, including high expression in 13 organs and no expression in only two organs; in 44 tissues, there was high expression in 31 tissues, medium expression in four tissues, low expression in two tissues, and no expression in the other seven tissues. In pan-cancers with 33 cancer types, SOX9 expression was significantly increased in fifteen cancers, including CESC, COAD, ESCA, GBM, KIRP, LGG, LIHC, LUSC, OV, PAAD, READ, STAD, THYM, UCES, and UCS, but significantly decreased in only two cancers (SKCM and TGCT) compared with the matched healthy tissues. It suggests that SOX9 expression is upregulated in the most cancer types (15/33) as a proto-oncogene. The fact that the decrease of SOX9 expression in SKCM and the increase of SOX9 in the cell lines of melanoma inhibit tumorigenicity in both mouse and human ex vivo models demonstrates that SOX9 could also be a tumor suppressor. Further analyzing the prognostic values for SOX9 expression in cancer individuals revealed that OS is long in ACC and short in LGG, CESC, and THYM, suggesting that high SOX9 expression is positively correlated with the worst OS in LGG, CESC, and THYM, which could be used as a prognostic maker. In addition, CD inhibited both protein and mRNA expressions of SOX9 in a dose-dependent manner in 22RV1, PC3, and H1975 cells, indicating CD's anticancer roles likely via SOX9 inhibition. Moreover, SOX9 might play an important role in tumor genesis and development by participating in immune infiltration. Altogether, SOX9 could be a biomarker for diagnostics and prognostics for pan-cancers and an emerging target for the development of anticancer drugs.

SOX9 is a target of miR-134-3p and miR-224-3p in breast cancer cell lines

The transcription factor SOX9 represents an important mediator of breast cancer progression. miRNAs are small non-coding RNAs inhibiting translation of target genes upon interaction with the 3'-UTR region of respective mRNA molecules. Deregulated miRNA expression is involved in hallmarks of cancer like sustained proliferation and inhibition of apoptosis. Here, we investigated the miRNA-mediated regulation of SOX9 expression in two breast cancer cell lines, thereby providing further insights into cellular mechanisms driving breast cancer progression. The modulating effects of miR-134-3p, miR-224-3p, and miR-6859-3p on SOX9 expression were analyzed by qPCR and Western blot in human MDA-MB-231 breast cancer cells. Direct binding of the above-mentioned miRNAs to the SOX9 3'-UTR was assessed by luciferase reporter assays and site-directed mutagenesis. Expression levels of the investigated miRNAs in tumor samples versus healthy tissues were analyzed in silico using publicly available databases. Transfection of miR-134-3p, miR-224-3p, or miR-6859-3p reduced SOX9 expression on mRNA and protein level. Reporter assays proved direct binding of miR-134-3p and miR-224-3p to the SOX9 3'-UTR in MDA-MB-231 and MCF-7 cells. Expression analysis performed in silico revealed reduced expression of both miRNAs in breast cancer tissues. We describe three novel miRNAs targeting SOX9 in human breast cancer cell lines. Among them miR-134-2p and miR-224-3p might act as tumor suppressors, whose down-regulation induces elevated SOX9 levels thereby promoting breast cancer progression.

Identification of potential models for predicting progestin insensitivity in patients with endometrial atypical hyperplasia and endometrioid endometrial cancer based on ATAC-Seq and RNA-Seq integrated analysis

Objective: The aim of this study was to establish predictive models based on the molecular profiles of endometrial lesions, which might help identify progestin-insensitive endometrial atypical hyperplasia (EAH) or endometrioid endometrial cancer (EEC) patients before progestin-based fertility-preserving treatment initiation.

Methods: Endometrial lesions from progestin-sensitive (PS, n = 7) and progestin-insensitive (PIS, n = 7) patients were prospectively collected before progestin treatment and then analyzed by ATAC-Seq and RNA-Seq. Potential chromatin accessibility and expression profiles were compared between the PS and PIS groups. Candidate genes were identified by bioinformatics analyses and literature review. Then expanded samples (n = 35) were used for validating bioinformatics data and conducting model establishment.

Results: ATAC-Seq and RNA-Seq data were separately analyzed and then integrated for the subsequent research. A total of 230 overlapping differentially expressed genes were acquired from ATAC-Seq and RNA-Seq integrated analysis. Further, based on GO analysis, REACTOME pathways, transcription factor prediction, motif enrichment, Cytoscape analysis and literature review, 25 candidate genes potentially associated with progestin insensitivity were identified. Finally, expanded samples were used for data verification, and based on these data, three predictive models comprising 9 genes (FOXO1, IRS2, PDGFC, DIO2, SOX9, BCL11A, APOE, FYN, and KLF4) were established with an overall predictive accuracy above 90%.

Conclusion: This study provided potential predictive models that might help identify progestin-insensitive EAH and EEC patients before fertility-preserving treatment.

MIR133A regulates cell proliferation, migration, and apoptosis by targeting SOX9 in human colorectal cancer cells

The human microRNA 133A (MIR133A) was identified as a CRC-associated miRNA. It was down-regulated in human CRC tissues. We identified the putative MIR133A1 and A2 target genes by comparing the transcriptome analysis data of MIR133A1 and A2 knock-in cells with the candidate MIR133A target genes predicted by bioinformatics tools. We identified 29 and 33 putative MIR133A and A2 direct target genes, respectively. Among them, we focused on the master transcription regulator gene SRY-box transcription factor 9 (SOX9), which exhibits a pleiotropic role in cancer. We confirmed that SOX9 is a direct target gene of MIR133A by luciferase reporter assay, quantitative RT-PCR, and western blot analysis. Overexpression of MIR133A in CRC cell lines significantly decreased SOX9 and its downstream PIK3CA-AKT1-GSK3B-CTNNB1 and KRAS-BRAF-MAP2K1-MAPK1/3 pathways and increased apoptosis. Furthermore, functional studies reveal that cell proliferation, colony formation, and migration ability were significantly decreased by MIR133A-overexpressed CRC cell lines. Knockdown of SOX9 in CRC cell lines by SOX9 gene silencing showed similar results. We also used a xenograft model to show that MIR133A overexpression suppresses tumor growth and proliferation. Our results suggest that MIR133A regulates cell proliferation, migration, and apoptosis by targeting SOX9 in human colorectal cancer.

CircSOX9 acts as a molecular sponge of miR-485-3p to promote the progression of nasopharyngeal carcinoma

Circular RNA (circRNA) plays a vital role in the occurrence and development of nasopharyngeal carcinoma (NPC). However, the role of certain specific circRNAs in NPC are still unknown. In this study, collect tumor samples and adjacent normal tissues from clinical NPC patients and detect the expression of circSOX9 by qRT-PCR. Use nucleoplasmic separation analysis, RNase R digestion assay and FISH to detect the characteristics of circSOX9. After knocking down circSOX9, clone formation experiment and transwell assay were used to detect the proliferation and invasion ability of nasopharyngeal carcinoma cells HONE1 and CNE2, and western blot was used to further detect the level of epithelial-mesenchymal transition (EMT). Use the database to screen for possible downstream target genes and verify them with dual-luciferase experiments. Bioinformatics analysis showed that circSOX9 was significantly up-regulated in NPC, and its expression level was positively correlated with the malignant progression of cancer. Data from function gain or loss studies showed that decrease of circSOX9 inhibited the invasion and proliferation of HONE1 and CNE2 cell lines. Further analysis proved that miR-485-3p was the downstream target of circSOX9. The luciferase test showed that by acting as a molecular sponge of miR-485-3p, circSOX9 promotes the proliferation and invasion of NPC cells, while miR-485-3p can target the expression of SOX9. In conclusion, circSOX9 acts as an oncogene in the progression of NPC through miR-485-3p/SOX9, indicating that circSOX9 can be used as a potential therapeutic target and predictive marker for nasopharyngeal carcinoma.

Fucoxanthin Is a Potential Therapeutic Agent for the Treatment of Breast Cancer

Breast cancer (BC) is one of the most common cancers diagnosed and the leading cause of cancer-related death in women. Although there are first-line treatments for BC, drug resistances and adverse events have been reported. Given the incidence of BC keeps increasing, seeking novel therapeutics is urgently needed. Fucoxanthin (Fx) is a dietary carotenoid commonly found in seaweeds and diatoms. Both in vitro and in vivo studies show that Fx and its deacetylated metabolite fucoxanthinol (Fxol) inhibit and prevent BC growth. The NF-κB signaling pathway is considered the major pathway contributing to the anti-proliferation, anti-angiogenesis and pro-apoptotic effects of Fx and Fxol. Other signaling molecules such as MAPK, MMP2/9, CYP and ROS are also involved in the anti-cancer effects by regulating the tumor microenvironment, cancer metastasis, carcinogen metabolism and oxidation. Besides, Fx also possesses anti-obesity effects by regulating UCP1 levels and lipid metabolism, which may help to reduce BC risk. More importantly, mounting evidence demonstrates that Fx overcomes drug resistance. This review aims to give an updated summary of the anti-cancer effects of Fx and summarize the underlying mechanisms of action, which will provide novel strategies for the development of Fx as an anti-cancer therapeutic agent.

iTRAQ-Based Proteome Profiling of Differentially Expressed Proteins in Insulin-Resistant Human Hepatocellular Carcinoma

Recently, the incidences of insulin resistance (IR) and IR-related complications have increased throughout the world, which also associate with poor prognosis in hepatocellular carcinoma (HCC). Numerous studies had been focused on the role of IR in tumorigenesis and prognosis of HCC. The proteomic analysis of IR related hepatocellular carcinoma had not been reported by now. In the present study, 196 differentially expressed proteins (DEPs) were identified between insulin resistant HepG2 cells and their parental cells, of which 109 proteins were downregulated and 87 proteins were upregulated. Bioinformatics analysis indicated that these DEPs were highly enriched in process of tumorigenesis and tumor progression. PPI network analysis showed that SOX9, YAP1 and GSK3β as the key nodes, were involved in Wnt and Hippo signaling pathways. Survival analysis revealed that high expression of SOX9 and PRKD3 were strongly associated with reduced patient survival rate. parallel reaction monitoring (PRM) and Western blot analysis were applied to verify the protein level of these four key nodes mentioned above, which showed the same trend as quantified by isobaric tags for relative and absolute quantitation (iTRAQ) and confirmed the reliability of our Proteome Profiling analysis. Our results indicated that IR related dysregulation of protein expression might participated in tumorigenesis and malignant phenotype of hepatocarcinoma cells.

SOX9 negatively regulates the RLR antiviral signaling by targeting MAVS

Mitochondrial virus-induced signal adaptor (MAVS), also known as VISA, IPS-1, and Cardif, is a crucial adaptor protein in the RIG-I-like receptor (RLR) signaling pathway. Upon viral infection, RIG-I recognizes viral dsRNA and further transfers it to mitochondria, where it binds to MAVS through its CARD domain, generating a series of signal cascades. Transduction through this signaling cascade leads to phosphorylation and nuclear translocation of interferon regulatory factor 3/7 (IRF3/IRF7) and activation of NF-κB, which ultimately produces type I interferon (IFN) and proinflammatory cytokines. Here, our experiments demonstrated that overexpression of SRY-related high-mobility group protein 9 (SOX9) significantly inhibited Sendai virus (SeV)-induced and MAVS-mediated activation of the IFN-β promoter and ISRE. However, knocking out the expression of SOX9 in cells promoted SeV-induced IFN-β promoter and ISRE activation. Further studies have shown that SOX9 interacts with MAVS and targets MAVS to inhibit the association of MAVS-TRAF2, thereby inhibiting MAVS-mediated TRAF2 ubiquitination. Taken together, these results indicate that SOX9 downregulates IFN-β expression and antiviral signal transduction by targeting MAVS.

The Role of the SOX9/lncRNA ANXA2P2/miR-361-3p/SOX9 Regulatory Loop in Cervical Cancer Cell Growth and Resistance to Cisplatin

Cervical cancer is a highly prevalent female malignancy. Presently, cisplatin (DDP) is a first-line agent for cervical cancer chemotherapy. However, its curative effect is limited because of chemo-resistance. It has been previously reported that SOX9 targeted and activated oncogenic genes, enhancing cervical cancer cell resistance to DDP. The effects of the SOX9/lncRNA ANXA2P2/miR-361-3p/SOX9 regulatory loop on cervical cancer cell growth and resistance to DDP have been demonstrated. miR-361-3p expression was decreased in DDP-resistant cervical cancer cells and tissues. Moreover, miR-361-3p overexpression inhibited the growth of resistant cervical cancer cells and the resistance to DDP, whereas miR-361-3p inhibition exerted opposite effects. miR-361-3p inhibited SOX9 expression through binding; the effects of miR-361-3p inhibition were partially reversed by SOX9 knockdown. LncRNA ANXA2P2 expression was elevated in DDP-resistant cervical cancer cells and tissues. LncRNA ANXA2P2 inhibited miR-361-3p expression by binding, thereby upregulating SOX9. LncRNA ANXA2P2 knockdown inhibited DDP-resistant cervical cancer cell growth and resistance to DDP, whereas the effects of lncRNA ANXA2P2 knockdown were partially reversed by miR-361-3p inhibition. SOX9 expression was elevated in DDP-resistant cervical cancer cells and tissues, and SOX9 activated lncRNA ANXA2P2 transcription by binding. Collectively, SOX9, lncRNA ANXA2P2, and miR-361-3p form a regulatory loop, modulating DDP-resistant cervical cancer cell growth and response to DDP treatment.

Hypoxia inducible factor-3α promotes osteosarcoma progression by activating KDM3A-mediated demethylation of SOX9

Hypoxia/oxygen-sensing signally is closely associated with many tumor progressions, including osteosarcoma (OS). Previous research principally focused on the function of hypoxia-inducible factor (HIF)-1α and HIF-2α as the major hypoxia-associated transcription factors in OS, however, the role of HIF-3α has not been investigated. Our study found that HIF-3α was upregulated in OS tissues and cell lines. HIF-3α overexpression facilitated cell proliferation and invasion, and inhibited apoptosis, whereas HIF-3α knockdown showed the opposite results. Chromatin immunoprecipitation analysis revealed that lysine demethylase 3A (KDM3A) expression was transcriptionally activated by HIF-3α under hypoxia, and KDM3A occupied the SRY-box transcription factor 9 (SOX9) gene promoter region through H3 lysine 9 dimethylation (H3K9me2). Additionally, rescue results revealed that KDM3A or SOX9 overexpression reversed the effects of HIF-3α silence on cell functions. The Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway inhibitor cucurbitacin I suppressed the promotive effects of HIF-3α overexpression on cell proliferation, invasion and TAK2/STAT3 pathway. Finally, OS cell line MG-63 transfected with HIF-3α short hairpin RNA (HIF-3α shRNA) were subcutaneously injected into nude mice, and the results found that HIF-3α knockdown significantly inhibited the xenograft tumor growth of OS in vivo. In conclusion, this study reveals that HIF-3α promotes OS progression in vitro and in vivo by activating KDM3A-mediated SOX9 promoter demethylation, which may provide a potential therapeutic mechanism for OS.

Circ_0075825 promotes gastric cancer progression via adsorbing miR-432-5p to modulate SOX9

METHODS

Circ_0075825 expression in adjacent tissues and GC tissues was evaluated by bioinformatics method and quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). How circ_0075825 regulated GC cell growth, migration, invasion, and apoptosis were investigated by cell counting kit-8 assay, transwell assay and flow cytometry. The targeted interplays among circ_0075825, and miR-432-5p and Sex-Determining Region Y-related high-mobility group box 9 (SOX9) were explored by bioinformatics analysis and luciferase reporter gene assay. The regulatory effects of circ_0075825 and miR-432-5p on SOX9 protein expression were probed by western blot.

RESULTS

Circ_0075825 expression was raised in GC tissues and cell lines. Circ_0075825 overexpression promoted the proliferative, migrative and invasive abilities of GC cells, while inhibiting apoptosis, while depletion of circ_0075825 suppressed the malignant biological behaviors of GC cells. SOX9 was identified as one of the direct target genes of miR-432-5p, and circ_0075825 repressed the expression of miR-432-5p, to induce the expression of SOX9. Furthermore, miR-432-5p overexpression counteracted the promoting effect of circ_0075825 on the malignancy of GC cells.

CONCLUSION

Circ_0075825 promotes GC progression via sponging miR-432-5p to regulate SOX9 expression level, and it may be a novel therapeutic target for treating GC.

Long non-coding RNA GAS6-AS1 enhances breast cancer cell aggressiveness by functioning as a competing endogenous RNA of microRNA-215-5p to enhance SOX9 expression

Long non-coding (lnc) RNAs play crucial functions in human cancer. However, until recently, the involvement of the lncRNA GAS6-AS1 in breast cancer (BCa) malignancy has not been studied exhaustively. The roles and underlying mode of action of GAS6-AS1 action in BCa progression were examined through functional experiments. A decline in GAS6-AS1 level led to a significant decrease in BCa cell proliferation, and the ability for colony formation. Here, GAS6-AS1 competed as endogenous RNA by sequestering microRNA-215-5p (miR-215-5p) causing an enhanced expression of SRY-box transcription factor 9 (SOX9). The effects of silencing GAS6-AS1 on BCa malignant phenotypes could be ameliorated by inhibiting miR-215-5p or restoring SOX9. Thus, GAS6-AS1 acted as a lncRNA that drives tumor in BCa, and enabled progression of BCa through miR-215-5p /SOX9 axis regulation. These outcomes show that the GAS6-AS1/miR-215-5p/SOX9 axis is a potentially effective target for cancer treatment and management.

Non-coding RNA-associated competitive endogenous RNA regulatory networks: Novel diagnostic and therapeutic opportunities for hepatocellular carcinoma

Hepatocellular carcinoma (HCC), as the most prevalent liver malignancy, is annually diagnosed in more than half a million people worldwide. HCC is strongly associated with hepatitis B and C viral infections as well as alcohol abuse. Obesity and nonalcoholic fatty liver disease (NAFLD) also significantly enhance the risk of liver cancer. Despite recent improvements in therapeutic approaches, patients diagnosed in advanced stages show poor prognosis. Accumulating evidence provides support for the regulatory role of non-coding RNAs (ncRNAs) in cancer. There are a variety of reports indicating the regulatory role of microRNAs (miRNAs) in different stages of HCC. Long non-coding RNAs (LncRNAs) exert their effects by sponging miRNAs and controlling the expression of miRNA-targeted genes. Circular RNAs (circRNAs) perform their biological functions by acting as transcriptional regulators, miRNA sponges and protein templates. Diverse studies have illustrated that dysregulation of competing endogenous RNA networks (ceRNETs) is remarkably correlated with HCC-causing diseases such as chronic viral infections, nonalcoholic steatohepatitis and liver fibrosis/cirrhosis. The aim of the current article was to provide an overview of the role and molecular mechanisms underlying the function of ceRNETs that modulate the characteristics of HCC such as uncontrolled cell proliferation, resistance to cell death, metabolic reprogramming, immune escape, angiogenesis and metastasis. The current knowledge highlights the potential of these regulatory RNA molecules as novel diagnostic biomarkers and therapeutic targets in HCC.

The Human Positive Cofactor 4 is a Promising Chemotherapeutic Target in Lung Adenocarcinoma

Reduced sensitivity to chemotherapeutic drugs is almost inevitable in lung adenocarcinoma patients. Thus, understanding the relevant mechanisms is urgent. Positive cofactor 4 (PC4) was at first revealed to be a coactivator of basal transcription. Previous research has shown that PC4 participates in various cellular processes in normal and malignant cells. However, it is still unknown whether PC4 participates in altering the lung adenocarcinoma cell sensitivity to chemotherapy, and the relevant mechanisms remain to be explained. In this study, we discovered that PC4 was overexpressed in cisplatin-resistant lung adenocarcinoma cells. PC4 decreased cisplatin's cytotoxic effects on lung adenocarcinoma in vivo and in vitro. Furthermore, PC4 positively correlated with SOX9 in multiple cancers. PC4 was an upstream regulator of SOX9 in lung adenocarcinoma. Furthermore, PC4 mediated lung adenocarcinoma cell sensitivity to the HIF-PH inhibitor DMOG and the mTOR inhibitor rapamycin, and PC4 mediated the synergistic effect of DMOG and cisplatin. Finally, PC4 destabilized HIF-1α upon cisplatin treatment. Our research showed that PC4 participates in mediating lung adenocarcinoma cell sensitivity to multiple drugs. Mechanistically, PC4 governs multiple downstream pathways associated with chemotherapy resistance, including the SOX9 and HIF-1α pathways. Thus, PC4 is a promising chemotherapeutic target in lung adenocarcinoma.

SOX9: Advances in Gynecological Malignancies

Transcription factors of the SOX family were first discovered in mammals in 1990. The sex-determining region Y box 9 belongs to the SOX transcription factor family. It plays an important role in inducing tissue and cell morphogenesis, survival, and many developmental processes. Furthermore, it has been shown to be an oncogene in many tumors. Gynecological malignancies are tumors that occur in the female reproductive system and seriously threaten the lives of patients. Common gynecological malignancies include ovarian cancer, cervical cancer, and endometrial cancer. So far, the molecular mechanisms related to the incidence and development of gynecological malignancies remain unclear. This makes it particularly important to discover their common causative molecule and thus provide an effective therapeutic target. In recent years, studies have found that multiple mechanisms are involved in regulating the expression of the sex-determining region Y box 9, leading to the occurrence and development of gynecological malignancies. In this review, we discuss the prognostic value of SOX9 expression and the potential of targeting SOX9 for gynecological malignancy treatment. We also discuss progress regarding the role of SOX9 in gynecological malignancy pathogenesis through its mediation of important mechanisms, including tumor initiation and proliferation, apoptosis, migration, invasion, chemoresistance, and stem cell maintenance.

Oncogenic role of SOX9-DHCR24-cholesterol biosynthesis axis in IGH-BCL2 positive diffuse large B-cell lymphomas

SOX9 plays an oncogenic role in germinal center B-cell type, IGH-BCL2⁺ DLBCL, by promoting cell proliferation and inhibiting apoptosis.

SOX9 drives lymphomagenesis through upregulation of DHCR24, the key final enzyme in the cholesterol biosynthesis pathway.

Although oncogenicity of the stem cell regulator SOX9 has been implicated in many solid tumors, its role in lymphomagenesis remains largely unknown. In this study, SOX9 was overexpressed preferentially in a subset of diffuse large B-cell lymphomas (DLBCLs) that harbor IGH-BCL2 translocations. SOX9 positivity in DLBCL correlated with an advanced stage of disease. Silencing of SOX9 decreased cell proliferation, induced G₁/S arrest, and increased apoptosis of DLBCL cells, both in vitro and in vivo. Whole-transcriptome analysis and chromatin immunoprecipitation–sequencing assays identified DHCR24, a terminal enzyme in cholesterol biosynthesis, as a direct target of SOX9, which promotes cholesterol synthesis by increasing DHCR24 expression. Enforced expression of DHCR24 was capable of rescuing the phenotypes associated with SOX9 knockdown in DLBCL cells. In models of DLBCL cell line xenografts, SOX9 knockdown resulted in a lower DHCR24 level, reduced cholesterol content, and decreased tumor load. Pharmacological inhibition of cholesterol synthesis also inhibited DLBCL xenograft tumorigenesis, the reduction of which is more pronounced in DLBCL cell lines with higher SOX9 expression, suggesting that it may be addicted to cholesterol. In summary, our study demonstrated that SOX9 can drive lymphomagenesis through DHCR24 and the cholesterol biosynthesis pathway. This SOX9-DHCR24-cholesterol biosynthesis axis may serve as a novel treatment target for DLBCLs.

Development of Dl1.72, a Novel Anti-DLL1 Antibody with Anti-Tumor Efficacy against Estrogen Receptor-Positive Breast Cancer

Simple Summary

Over 70% of breast cancers (BCs) are estrogen receptor-positive (ER⁺). The development of endocrine therapy has considerably improved patient outcomes. However, there is a clinical need for novel effective therapies against ER⁺ BCs, since many of these do not respond to standard therapy, and more than one-third of responders acquire resistance, experience relapse and metastasize. The Notch ligand Delta-like 1 (DLL1) is a key player in ER⁺ BC development and aggressiveness. Contrary to complete Notch pharmacological inhibitors, antibody-targeting of individual Notch components is expected to have superior therapeutic efficacy and be better tolerated. In this study, we developed and characterized a novel specific anti-DLL1 antibody with efficacy in inhibiting BC cell proliferation, mammosphere formation and angiogenesis, as well as anti-tumor and anti-metastatic efficacy in an ER⁺ BC mouse model without side effects. Thus, our data suggest that this anti-DLL1 antibody is a promising candidate for ER⁺ BC treatment.

Abstract

The Notch-signaling ligand DLL1 has emerged as an important player and promising therapeutic target in breast cancer (BC). DLL1-induced Notch activation promotes tumor cell proliferation, survival, migration, angiogenesis and BC stem cell maintenance. In BC, DLL1 overexpression is associated with poor prognosis, particularly in estrogen receptor-positive (ER⁺) subtypes. Directed therapy in early and advanced BC has dramatically changed the natural course of ER⁺ BC; however, relapse is a major clinical issue, and new therapeutic strategies are needed. Here, we report the development and characterization of a novel monoclonal antibody specific to DLL1. Using phage display technology, we selected an anti-DLL1 antibody fragment, which was converted into a full human IgG1 (Dl1.72). The Dl1.72 antibody exhibited DLL1 specificity and affinity in the low nanomolar range and significantly impaired DLL1-Notch signaling and expression of Notch target genes in ER⁺ BC cells. Functionally, in vitro treatment with Dl1.72 reduced MCF-7 cell proliferation, migration, mammosphere formation and endothelial tube formation. In vivo, Dl1.72 significantly inhibited tumor growth, reducing both tumor cell proliferation and liver metastases in a xenograft mouse model, without apparent toxicity. These findings suggest that anti-DLL1 Dl1.72 could be an attractive agent against ER⁺ BC, warranting further preclinical investigation.

Sublytic C5b-9 triggers glomerular mesangial cell proliferation via enhancing FGF1 and PDGFα gene transcription mediated by GCN5-dependent SOX9 acetylation in rat Thy-1 nephritis

Rat Thy-1 nephritis (Thy-1N) is an animal model of human mesangioproliferative glomerulonephritis (MsPGN), accompanied by glomerular mesangial cell (GMC) proliferation and extracellular matrix (ECM) deposition. Although sublytic C5b-9 formed on GMC membrane could induce cell proliferation, the mechanism is still unclear. In this study, we first demonstrated that the level of SRY related HMG-BOX gene 9 (SOX9), general control nonderepressible 5 (GCN5), fibroblast growth factor 1 (FGF1) and platelet-derived growth factor α (PDGFα) was all elevated both in the renal tissues of Thy-1N rats (in vivo) and in the GMCs (in vitro) with sublytic C5b-9 stimulation. Then, we not only discovered that sublytic C5b-9 caused GMC proliferation through increasing SOX9, GCN5, FGF1 and PDGFα expression, but also proved that SOX9 and GCN5 formed a complex and combined with FGF1 and PDGFα promoters, leading to FGF1 and PDGFα gene transcription. More importantly, GCN5 could mediate SOX9 acetylation at lysine 62 (K62) to enhance SOX9 binding to FGF1 or PDGFα promoter and promote FGF1 or PDGFα synthesis and GMC proliferation. Besides, the experiments in vivo also showed that FGF1 and PDGFα expression, GMC proliferation and urinary protein secretion in Thy-1N rats were greatly reduced by silencing renal SOX9, GCN5, FGF1 or PDGFα gene. Furthermore, the renal tissues of MsPGN patients also exhibited positive expression of these genes mentioned above. Collectively, our findings indicate that GCN5, SOX9 and FGF1/PDGFα can form an axis and play an essential role in sublytic C5b-9-triggered GMC proliferation, which might provide a novel insight into the pathogenesis of Thy-1N and MsPGN.

RIP140 Represses Intestinal Paneth Cell Differentiation and Interplays with SOX9 Signaling in Colorectal Cancer

RIP140 is a major transcriptional coregulator of gut homeostasis and tumorigenesis through the regulation of Wnt/APC signaling. Here, we investigated the effect of RIP140 on Paneth cell differentiation and its interplay with the transcription factor SOX9. Using loss of function mouse models, human colon cancer cells, and tumor microarray data sets we evaluated the role of RIP140 in SOX9 expression and activity using RT-qPCR, immunohistochemistry, luciferase reporter assays, and GST-pull down. We first evidence that RIP140 strongly represses the Paneth cell lineage in the intestinal epithelium cells by inhibiting Sox9 expression. We then demonstrate that RIP140 interacts with SOX9 and inhibits its transcriptional activity. Our results reveal that the Wnt signaling pathway exerts an opposite regulation on SOX9 and RIP140. Finally, the levels of expression of RIP140 and SOX9 exhibit a reverse response and prognosis value in human colorectal cancer biopsies. This work highlights an intimate transcriptional cross-talk between RIP140 and SOX9 in intestinal physiopathology.

Downregulation of SOX9 suppresses breast cancer cell proliferation and migration by regulating apoptosis and cell cycle arrest

SRY-related high-mobility group box 9 (SOX9) is an important transcriptional factor that regulates diverse genes involved in development and stemness. Dysregulation of SOX9 encourages carcinogenesis in various types of cancer, including breast cancer. The present study aimed to explore the role of SOX9 in triple-negative breast cancer (TNBC). SOX9 expression was significantly upregulated in the TNBC MDA-MB-231, MDA-MB-436 and MDA-MB-468 cell lines compared with that in BT-549 cells. Based on a lentivirus assay, SOX9 inhibition in MDA-MB-231 and MDA-MB-436 cells suppressed cell proliferation and colony formation. Apoptosis was increased and the cell cycle was arrested at the G₀/G₁ phase in SOX9-knockdown cells. Transwell and wound-healing assays demonstrated that SOX9 inhibition decreased the migration and invasion of MDA-MB-231 and MDA-MB-436 cells. RNA sequencing identified that numerous genes were regulated by SOX9, including nucleophosmin, thioredoxin reductase 1, succinate dehydrogenase complex subunit D, nuclear receptor binding SET domain protein 2, eukaryotic translation initiation factor 4γ1 and glycogen phosphorylase L. Overall, the current study suggested that SOX9 acted as an oncogene in TNBC.

Interplay between SOX9 transcription factor and microRNAs in cancer

SOX transcription factors are critical regulators of development, homeostasis and disease progression and their dysregulation is a common finding in various cancers. SOX9 belongs to SOXE family located on chromosome 17. MicroRNAs (miRNAs) possess the capacity of regulating different transcription factors in cancer cells by binding to 3'-UTR. Since miRNAs can affect differentiation, migration, proliferation and other physiological mechanisms, disturbances in their expression have been associated with cancer development. In this review, we evaluate the relationship between miRNAs and SOX9 in different cancers to reveal how this interaction can affect proliferation, metastasis and therapy response of cancer cells. The tumor-suppressor miRNAs can decrease the expression of SOX9 by binding to the 3'-UTR of mRNAs. Furthermore, the expression of downstream targets of SOX9, such as c-Myc, Wnt, PI3K/Akt can be affected by miRNAs. It is noteworthy that other non-coding RNAs including lncRNAs and circRNAs regulate miRNA/SOX9 expression to promote/inhibit cancer progression and malignancy. The pre-clinical findings can be applied as biomarkers for diagnosis and prognosis of cancer patients.

Targeting FAK in anticancer combination therapies

Focal adhesion kinase (FAK) is both a non-receptor tyrosine kinase and an adaptor protein that primarily regulates adhesion signalling and cell migration, but FAK can also promote cell survival in response to stress. FAK is commonly overexpressed in cancer and is considered a high-value druggable target, with multiple FAK inhibitors currently in development. Evidence suggests that in the clinical setting, FAK targeting will be most effective in combination with other agents so as to reverse failure of chemotherapies or targeted therapies and enhance efficacy of immune-based treatments of solid tumours. Here, we discuss the recent preclinical evidence that implicates FAK in anticancer therapeutic resistance, leading to the view that FAK inhibitors will have their greatest utility as combination therapies in selected patient populations.

EGR1 promotes stemness and predicts a poor outcome of uterine cervical cancer by inducing SOX9 expression

BACKGROUND

Early growth response-1 (EGR1) is a transcription factor involved in the progression of several cancer types. However, the expression and clinical significance of EGR1 in uterine cervical cancer (CC) have not been elucidated.

OBJECTIVE

To investigate the expression, clinical significance and prognostic value of EGR1 in CC.

METHODS

The expression of EGR1 was detected in 13 CCs and paired adjacent tissues with qRT-PCR and in 144 CC tissues with immunohistochemistry (IHC). The IHC scores were used to divide the patients into subsets with low and high EGR1 expression. The correlations between the EGR1 expression and clinicopathological factors were analyzed with the chi-square test, and the prognostic significance of EGR1 expression was evaluated with univariate and multivariate analyses. The functions of EGR1 in the proliferation, invasion and stemness of CC cells were investigated, and the molecular mechanism was assessed by in vitro experiments.

RESULTS

High expression of EGR1 was significantly associated with low survival rates of CC. EGR1 is an independent prognostic biomarker of CC, and its high expression predicted a poor outcome. EGR1 facilitated stemness and thus promoted proliferation and invasion of CC cells. SOX9 played an essential role in the EGR1-induced progression of CC cells.

CONCLUSIONS

EGR1 is an independent prognostic biomarker of CC. High EGR1 expression promoted proliferation, invasion and stemness by increasing SOX9 expression in CC cells. Our results suggested that the EGR1-SOX9 axis may be a potential drug target and that blocking the EGR1-SOX9 axis may be a possible approach to treating CC.

H3K27 demethylase KDM6B aggravates ischemic brain injury through demethylation of IRF4 and Notch2-dependent SOX9 activation

Lysine demethylase 6B (KDM6B) is a histone H3 lysine 27 (H3K27) demethylase that serves as a key mediator of gene transcription. Although KDM6B has been reported to modulate neuroinflammation after ischemic stroke, its role in ischemic brain injury is yet to be well elucidated. Therefore, this study aimed to thoroughly demonstrate the molecular mechanism underlying the effect of KDM6B on neurological function and astrocyte response in post-ischemic brain injury. Middle cerebral artery occlusion/reperfusion (MCAO) mouse models were constructed, while the oxygen-glucose deprivation/reperfusion (OGD/R) model was developed in astrocytes to mimic injury conditions. KDM6B was upregulated post-MCAO in mice and in astrocytes following the induction of OGD/R. Silencing of KDM6B resulted in suppressed neurological deficit, reduced cerebral infarction volume, attenuated neuronal cell apoptosis, and disrupted inflammation. Dual-luciferase reporter gene and chromatin immunoprecipitation-quantitative polymerase chain reaction assays revealed that KDM6B inhibited H3K27 trimethylation in the interferon regulatory factor 4 (IRF4) promoter region, resulting in the upregulation of IRF4 expression, which in turn bound to the Notch2 promoter region to induce its downstream factor SRY-related high-mobility group box 9 (SOX9). SOX9 knockdown reversed the effects of KDM6B overexpression on ischemia-triggered brain damage. Based on these findings, we concluded that KDM6B-mediated demethylation of IRF4 contributes to aggravation of ischemic brain injury through SOX9 activation.

Circ_0109046 promotes the malignancy of endometrial carcinoma cells through the microRNA-105/SOX9/Wnt/β-catenin axis

Emerging evidence suggests the important involvements of circular RNAs (circRNAs) in cancer progression. This study focuses on the function of Circ_0109046 on the malignancy of endometrial carcinoma (EC) cells and the molecules involved. First, high expression of Circ_0109046 was found in EC tissues compared to the adjacent tissues, and it predicted unfavorable prognosis in patients. Similarly, high expression of Circ_0109046 was confirmed in EC cells relative to that in normal endometrial epithelial cells. Silencing of Circ_0109046 in AN3-CA cells inhibited proliferation and aggressiveness but increased apoptosis of cells. Circ_0109046 was mainly sub-localized in cytoplasm, and it mediated SOX9 expression through sponging microRNA (miR)-105. The proliferation and aggressiveness of EC cells suppressed by Circ_0109046 downregulation was recovered upon SOX9 overexpression. SOX9 activated the Wnt/β-catenin pathway. Furthermore, downregulation of Circ_0109046 reduced the growth of xenograft tumors in nude mice. This study evidenced that Circ_0109046 upregulates SOX9 expression through sponging miR105, leading to activation of Wnt/β-catenin signaling and the malignant growth of EC. This study may offer novel understanding in EC treatment.

Long Non-Coding RNA LINC01089 Enhances the Development of Gastric Cancer by Sponging miR-145-5p to Mediate SOX9 Expression

BACKGROUND

Long non-coding RNAs (lncRNAs) have potential regulatory effects in oncogenesis. Previous studies showed that several lncRNAs could participate in the progression of gastric cancer (GC). However, the specific biological mechanisms in GC are still unclear. We analyzed an lncRNA microarray of GC and selected LINC01089 for study.

METHODS

LINC01089 expression in GC was tested by qRT-PCR. GC cell proliferation was assessed using CCK-8 and EdU assays. Cell invasion was assessed using the Transwell assay. A dual-luciferase reporter gene assay and bioinformatics assay were performed to detect potential targets of LINC01089. Additionally, RNA immunoprecipitation and Western blot assays were performed to clarify their interactions and roles in the regulation of GC progression.

RESULTS

High LINC01089 expression was observed in GC cells. LINC01089 overexpression notably expedited cell migration, proliferation, and invasion. LINC01089 positively regulated SOX9 expression by competitively binding to microRNA (miR-145-5p).

CONCLUSION

LINC01089 competitively binds to miR-145-5p to mediate SOX9 expression. LINC01089 may participate in the progression of GC.