High expression of SULF1 is associated with adverse prognosis in breast cancer brain metastasis

BACKGROUND

Breast cancer is the most common cancer in women, and in advanced stages, it often metastasizes to the brain. However, research on the biological mechanisms of breast cancer brain metastasis and potential therapeutic targets are limited.

METHODS

Differential gene expression analysis (DEGs) for the datasets GSE43837 and GSE125989 from the GEO database was performed using online analysis tools such as GEO2R and Sangerbox. Further investigation related to SULF1 was conducted using online databases such as Kaplan-Meier Plotter and cBioPortal. Thus, expression levels, variations, associations with HER2, biological processes, and pathways involving SULF1 could be analyzed using UALCAN, cBioPortal, GEPIA2, and LinkedOmics databases. Moreover, the sensitivity of SULF1 to existing drugs was explored using drug databases such as RNAactDrug and CADSP.

RESULTS

High expression of SULF1 was associated with poor prognosis in advanced breast cancer brain metastasis and was positively correlated with the expression of HER2. In the metastatic breast cancer population, SULF1 ranked top among the 16 DEGs with the highest mutation rate, reaching 11%, primarily due to amplification. KEGG and GSEA analyses revealed that the genes co-expressed with SULF1 were positively enriched in the 'ECM-receptor interaction' gene set and negatively enriched in the 'Ribosome' gene set. Currently, docetaxel and vinorelbine can act as treatment options if the expression of SULF1 is high.

CONCLUSIONS

This study, through bioinformatics analysis, unveiled SULF1 as a potential target for treating breast cancer brain metastasis (BM).

6-O-endosulfatases in tumor metastasis: heparan sulfate proteoglycans modification and potential therapeutic targets

Metastasis is the leading cause of cancer-associated mortality. Although advances in the targeted treatment and immunotherapy have improved the management of some cancers, the prognosis of metastatic cancers remains unsatisfied. Therefore, the specific mechanisms in tumor metastasis need further investigation. 6-O-endosulfatases (SULFs), comprising sulfatase1 (SULF1) and sulfatase 2 (SULF2), play pivotal roles in the post-synthetic modifications of heparan sulfate proteoglycans (HSPGs). Consequently, these extracellular enzymes can regulate a variety of downstream pathways by modulating HSPGs function. During the past decades, researchers have detected the expression of SULF1 and SULF2 in most cancers and revealed their roles in tumor progression and metastasis. Herein we reviewed the metastasis steps which SULFs participated in, elucidated the specific roles and mechanisms of SULFs in metastasis process, and discussed the effects of SULFs in different types of cancers. Moreover, we summarized the role of targeting SULFs in combination therapy to treat metastatic cancers, which provided some novel strategies for cancer therapy.

[Identification of SULF1 as a Shared Gene in Idiopathic Pulmonary Fibrosis and Lung Adenocarcinoma]

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an idiopathic chronic, progressive interstitial lung disease with a diagnosed median survival of 3-5 years. IPF is associated with an increased risk of lung cancer. Therefore, exploring the shared pathogenic genes and molecular pathways between IPF and lung adenocarcinoma (LUAD) holds significant importance for the development of novel therapeutic approaches and personalized precision treatment strategies for IPF combined with lung cancer.

METHODS

Bioinformatics analysis was conducted using publicly available gene expression datasets of IPF and LUAD from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis was employed to identify common genes involved in the progression of both diseases, followed by functional enrichment analysis. Subsequently, additional datasets were used to pinpoint the core shared genes between the two diseases. The relationship between core shared genes and prognosis, as well as their expression patterns, clinical relevance, genetic characteristics, and immune-related functions in LUAD, were analyzed using The Cancer Genome Atlas (TCGA) database and single-cell RNA sequencing datasets. Finally, potential therapeutic drugs related to the identified genes were screened through drug databases.

RESULTS

A total of 529 shared genes between IPF and LUAD were identified. Among them, SULF1 emerged as a core shared gene associated with poor prognosis. It exhibited significantly elevated expression levels in LUAD tissues, concomitant with high mutation rates, genomic heterogeneity, and an immunosuppressive microenvironment. Subsequent single-cell RNA-seq analysis revealed that the high expression of SULF1 primarily originated from tumor-associated fibroblasts. This study further demonstrated an association between SULF1 expression and tumor drug sensitivity, and it identified potential small-molecule drugs targeting SULF1 highly expressed fibroblasts.

CONCLUSIONS

This study identified a set of shared molecular pathways and core genes between IPF and LUAD. Notably, SULF1 may serve as a potential immune-related biomarker and therapeutic target for both diseases.

SULF1 Activates the VEGFR2/PI3K/AKT Pathway to Promote the Development of Cervical Cancer

BACKGROUND AND PURPOSE

Sulfatase 1 (SULF1) can regulate the binding of numerous signaling molecules by removing 6-O-sulfate from heparan sulfate proteoglycans (HSPGs) to affect numerous physiological and pathological processes. Our research aimed to investigate the effect of the SULF1-mediated VEGFR2/PI3K/AKT signaling pathway on tumorigenesis and development of cervical cancer (CC).

METHODS

The expression and prognostic values of SULF1 in patients with CC were analyzed through bioinformatics analysis, RT-PCR, immunohistochemistry, and western blot assays. The function and regulatory mechanism of SULF1 in proliferation, migration, and invasion of cervical cancer cells were examined through lentivirus transduction, CCK8, flow cytometry analysis, plate colony formation assay, scratch assay, transwell assay, western blot, VEGFR2 inhibitor (Ki8751), and mouse models.

RESULTS

SULF1 expression was significantly upregulated in CC tissues, which was significantly associated with poor prognosis of patients with CC. In vitro, the upregulation of SULF1 expression in cervical cancer HeLa cells promoted cell proliferation, colony formation, migration, and invasion while inhibiting apoptosis. Conversely, the downregulation of SULF1 expression had the opposite effect. In vivo, the upregulation of SULF1 expression resulted in a significant increase in both tumor growth and angiogenesis, while its downregulation had the opposite effect. Furthermore, western blot detection and cell function rescue assay confirmed that the upregulation of SULF1 in HeLa cells promoted the tumorigenic behaviors of cancer cells by activating the VEGFR2/PI3K/AKT signaling pathway.

CONCLUSION

SULF1 plays an oncogenic role in the tumorigenesis and development of CC, indicating its potential as a novel molecular target for gene-targeted therapy in patients with CC.

EZH2/hSULF1 axis mediates receptor tyrosine kinase signaling to shape cartilage tumor progression

Chondrosarcomas are primary cancers of cartilaginous tissue and capable of alteration to highly aggressive, metastatic, and treatment-refractory states, leading to a poor prognosis with a five-year survival rate at 11 months for dedifferentiated subtype. At present, the surgical resection of chondrosarcoma is the only effective treatment, and no other treatment options including targeted therapies, conventional chemotherapies, or immunotherapies are available for these patients. Here, we identify a signal pathway way involving EZH2/SULF1/cMET axis that contributes to malignancy of chondrosarcoma and provides a potential therapeutic option for the disease. A non-biased chromatin immunoprecipitation sequence, cDNA microarray analysis, and validation of chondrosarcoma cell lines identified sulfatase 1 (SULF1) as the top EZH2-targeted gene to regulate chondrosarcoma progression. Overexpressed EZH2 resulted in downregulation of SULF1 in chondrosarcoma cell lines, which in turn activated cMET pathway. Pharmaceutical inhibition of cMET or genetically silenced cMET pathway significantly retards the chondrosarcoma growth and extends mice survival. The regulation of EZH2/SULF1/cMET axis were further validated in patient samples with chondrosarcoma. The results not only established a signal pathway promoting malignancy of chondrosarcoma but also provided a therapeutic potential for further development of effective target therapy to treat chondrosarcoma.

Extracellular Heparan 6-O-Endosulfatases SULF1 and SULF2 in Head and Neck Squamous Cell Carcinoma and Other Malignancies

Pan-cancer analysis of TCGA and CPTAC (proteomics) data shows that SULF1 and SULF2 are oncogenic in a number of human malignancies and associated with poor survival outcomes. Our studies document a consistent upregulation of SULF1 and SULF2 in HNSC which is associated with poor survival outcomes. These heparan sulfate editing enzymes were considered largely functional redundant but single-cell RNAseq (scRNAseq) shows that SULF1 is secreted by cancer-associated fibroblasts in contrast to the SULF2 derived from tumor cells. Our RNAScope and patient-derived xenograft (PDX) analysis of the HNSC tissues fully confirm the stromal source of SULF1 and explain the uniform impact of this enzyme on the biology of multiple malignancies. In summary, SULF2 expression increases in multiple malignancies but less consistently than SULF1, which uniformly increases in the tumor tissues and negatively impacts survival in several types of cancer even though its expression in cancer cells is low. This paradigm is common to multiple malignancies and suggests a potential for diagnostic and therapeutic targeting of the heparan sulfatases in cancer diseases.

Rs3802278 in 3'-UTR of SULF1 associated with platinum resistance and survival in Chinese epithelial ovarian cancer patients

Ovarian cancer is the leading cause of death from gynecologic cancers, but platinum resistance remains a major obstacle in the chemotherapy of ovarian cancer. This study aims to examine the role of polymorphisms in sulfatase 1 (SULF1) in platinum resistance and survival in advanced epithelial ovarian cancer (EOC) patients. We genotyped 12 SNPs of SULF1 in 195 EOC patients treated with platinum using MassARRAY method and evaluated the association between the SNPs and platinum response. SULF1 rs3802278 was marginal significantly associated with platinum resistance in recessive model with p value of 0.055. The patients with SULF1 rs3802278 AA were more resistant to platinum-based chemotherapy comparing to those with AG/GG genotype (OR: 2.317, 95%CI: 0.982 ∼ 5.465). In survival analysis, rs3802278 was significantly associated with both of PFS and OS after adjusted by FIGO stage and age. Patients with AA genotypes showed a shorter PFS and OS than with AG/GG genotypes (median PFS: 15 months vs. 21 months, p = 0.010, HR = 1.876, 95%CI: 1.165-3.022; median OS: 42 months vs. 73 months, p = 0.031, HR = 1.928, 95%CI: 1.061-3.504). SULF1 rs3802278 may serve as a potential candidate biomarker for the prediction of platinum resistance and prognosis in Chinese EOC patients.

Development of novel monoclonal antibodies and immunoassays for sensitive and specific detection of SULF1 endosulfatase

BACKGROUND

Cell-surface heparan sulfate proteoglycans (HSPGs) function as receptors or co-receptors for ligand binding and mediate the transmission of critical extracellular signals into cells. The complex and dynamic modifications of heparan sulfates on the core proteins are highly regulated to achieve precise signaling transduction. Extracellular endosulfatase Sulf1 catalyzes the removal of 6-O sulfation from HSPGs and thus regulates signaling mediated by 6-O sulfation on HSPGs. The expression of Sulf1 is altered in many cancers. Further studies are needed to clarify Sulf1 role in tumorigenesis, and new tools that can expand our knowledge in this field are required.

METHODS

We have developed and validated novel SULF1 monoclonal antibodies (mAbs). The isotype and subclass for each of these antibodies were determined. These antibodies provide invaluable reagents to assess SULF1- tissue and blood levels by immunohistochemistry and ELISA assays, respectively.

RESULTS

This study reports novel mAbs and immunoassays developed for sensitive and specific human Sulf1 protein detection. Using these SULF1 mAbs, we developed an ELISA assay to investigate whether blood-derived SULF1 may be a useful biomarker for detecting cancer early. Furthermore, we have demonstrated the utility of these antibodies for Sulf1 protein detection, localization, and quantification in biospecimens using various immunoassays.

CONCLUSIONS

This study describes novel Sulf1 mAbs suitable for various immunoassays, including Western blot analysis, ELISA, and immunohistochemistry, which can help understand Sulf1 pathophysiological role.

GENERAL SIGNIFICANCE

New tools to assess and clarify SULF1 role in tumorigenesis are needed. Our novel Sulf1 mAbs and immunoassays assay may have utility for such application.

An investigation of genetic polymorphisms in heparan sulfate proteoglycan core proteins and key modification enzymes in an Australian Caucasian multiple sclerosis population

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system in young adults. Heparan sulfate proteoglycans (HSPGs) are ubiquitous to the cell surface and the extracellular matrix. HSPG biosynthesis is a complex process involving enzymatic attachment of heparan sulfate (HS) chains to a core protein. HS side chains mediate specific ligand and growth factor interactions directing cellular processes including cell adhesion, migration and differentiation. Two main families of HSPGs exist, the syndecans (SDC1-4) and glypicans (GPC1-6). The SDCs are transmembrane proteins, while the GPC family are GPI linked to the cell surface. SDC1 has well-documented interactions with numerous signalling pathways. Genome-wide association studies (GWAS) have identified regions of the genome associated with MS including a region on chromosome 13 containing GPC5 and GPC6. International studies have revealed significant associations between this region and disease development. The exostosin-1 (EXT1) and sulfatase-1 (SULF1) are key enzymes contributing to the generation of HS chains. EXT1, with documented tumour suppressor properties, is involved in the initiation and polymerisation of the growing HS chain. SULF1 removes 6-O-sulfate groups from HS chains, affecting protein-ligand interactions and subsequent downstream signalling with HS modification potentially having significant effects on MS progression. In this study, we identified significant associations between single nucleotide polymorphisms in SDC1, GPC5 and GPC6 and MS in an Australian Caucasian case-control population. Further significant associations in these genes were identified when the population was stratified by sex and disease subtype. No association was found for EXT1 or SULF1.

The histone demethylase JMJD2B regulates endothelial-to-mesenchymal transition

Here we show that the histone demethylase JMJD2B is induced in endothelial cells by EndMT provoking stimuli and thereby contributes to the acquirement of a mesenchymal/smooth muscle phenotype. Silencing of JMJD2B inhibited EndMT in vitro and reduced the induction of EndMT after myocardial infarction in vivo. Inhibition of JMJD2B prevents the demethylation of repressive trimethylated histone H3 at lysine 9 (H3K9me3) at promoters of mesenchymal and EndMT-controlling genes, thereby reducing EndMT. Together, our study reports a crucial role for JMJD2B in controlling histone modifications during the transition of endothelial cells toward a mesenchymal phenotype.

Endothelial cells play an important role in maintenance of the vascular system and the repair after injury. Under proinflammatory conditions, endothelial cells can acquire a mesenchymal phenotype by a process named endothelial-to-mesenchymal transition (EndMT), which affects the functional properties of endothelial cells. Here, we investigated the epigenetic control of EndMT. We show that the histone demethylase JMJD2B is induced by EndMT-promoting, proinflammatory, and hypoxic conditions. Silencing of JMJD2B reduced TGF-β2-induced expression of mesenchymal genes, prevented the alterations in endothelial morphology and impaired endothelial barrier function. Endothelial-specific deletion of JMJD2B in vivo confirmed a reduction of EndMT after myocardial infarction. EndMT did not affect global H3K9me3 levels but induced a site-specific reduction of repressive H3K9me3 marks at promoters of mesenchymal genes, such as Calponin (CNN1), and genes involved in TGF-β signaling, such as AKT Serine/Threonine Kinase 3 (AKT3) and Sulfatase 1 (SULF1). Silencing of JMJD2B prevented the EndMT-induced reduction of H3K9me3 marks at these promotors and further repressed these EndMT-related genes. Our study reveals that endothelial identity and function is critically controlled by the histone demethylase JMJD2B, which is induced by EndMT-promoting, proinflammatory, and hypoxic conditions, and supports the acquirement of a mesenchymal phenotype.

Loss of ZNF587B and SULF1 contributed to cisplatin resistance in ovarian cancer cell lines based on Genome-scale CRISPR/Cas9 screening

Ovarian cancer is one of the most lethal malignancies of the female reproductive system. Platinum-resistance is the major obstacle in the successful treatment of ovarian cancer. Previous studies largely failed to identify the key genes associated with platinum-resistance by using candidate genes testing, bioinformatic analysis and GWAS method. The aim of the study was to utilize the whole human Genome-scale CRISPR-Cas9 knockout (GeCKO) library to screen for novel genes involved in cisplatin resistance in ovarian cancer cell lines. The GeCKO library targeted 19052 genes with 122417 unique guide sequences. Six candidate genes had been screened out including one previously validated gene SULF1 and five novel genes ZNF587B, TADA1, SEMA4G, POTEC and USP17L20. After validated by CCK-8 and RT-PCR analysis, two genes (ZNF587B and SULF1) were discovered to be involved in cisplatin resistance. ZNF587B may serve as a new biomarker for predicting cisplatin resistance.

Sulfatase-1 overexpression indicates poor prognosis in urothelial carcinoma of the urinary bladder and upper tract

Urothelial carcinoma (UC), arising from the urothelium of the urinary tract, can occur in the upper (UTUC) and the urinary bladder (UBUC). A representative molecular aberration for UC characteristics and prognosis remains unclear. Data mining of Gene Expression Omnibus focusing on UBUC, we identified sulfatase-1 (SULF1) upregulation is associated with UC progression. SULF1 controls the sulfation status of heparan sulfate proteoglycans and plays a role in tumor growth and metastasis, while its role is unexplored in UC. To first elucidate the clinical significance of SULF1 transcript expression, real-time quantitative RT-PCR was performed in a pilot study of 24 UTUC and 24 UBUC fresh samples. We identified that increased SULF1 transcript abundance was associated with higher primary tumor (pT) status. By testing SULF1 immunoexpression in independent UTUC and UBUC cohorts consisted of 340 and 295 cases, respectively, high SULF1 expression was significantly associated with advanced pT and nodal status, higher histological grade and presence of vascular invasion in both UTUC and UBUC. In multivariate survival analyses, high SULF1 expression was independently associated with worse DSS (UTUC hazard ratio [HR] = 3.574, P < 0.001; UBUC HR = 2.523, P = 0.011) and MeFS (UTUC HR = 3.233, P < 0.001; UBUC HR = 1.851, P = 0.021). Furthermore, depletion of SULF1 expression by using RNA interference leaded to impaired cell proliferative, migratory, and invasive abilities in vitro. In addition, we further confirmed oncogenic role of SULF1 with gain-of function experiments. In conclusion, our findings implicate the oncogenic role of SULF1 expression in UC, suggesting SULF1 as a prognostic and therapeutic target of UC.

Single-nucleotide polymorphism in microRNA-binding site of SULF1 target gene as a protective factor against the susceptibility to breast cancer: a case-control study

Purpose

Numerous clinical studies have suggested that chemopreventive drugs for breast cancer such as tamoxifen and exemestane can effectively reduce the incidence of estrogen receptor (ER)-positive breast cancer. However, it remains unclear how to identify those who are susceptible to ER-positive breast cancer. Accordingly, there is a great demand for a probe into the predisposing factors so as to provide precise chemoprevention. Recent evidence has indicated that ERα expression can be regulated by microRNAs (miRNAs), such as miR-206, in breast cancer. We assumed that single-nucleotide polymorphisms (SNPs) in the miR-206-binding sites of the target genes may be associated with breast cancer susceptibility with different ER statuses.

Methods

We genotyped the SNPs that reside in and around the miR-206-binding sites of two target genes – heparan sulfatase 1 (SULF1) and RPTOR-independent companion of mammalian target of rapamycin Complex 2 (RICTOR) – which were related to the progression or metastasis of breast cancer cells in 710 breast cancer patients and 294 controls by the matrix-assisted laser desorption ionization-time of flight mass spectrometry method. Modified odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated by a multivariate logistic regression analysis to evaluate the potential association between the SNPs and breast cancer susceptibility.

Results

For rs3802278, which is located in the 3′-untranslated region (3′-UTR) of SULF1, the frequency of the AA genotype was less in breast cancer patients than that in the controls as compared to that of the GG + GA genotype not only for ER-positive breast cancer patients (adjusted OR =0.663, P=0.032) but also for hormone receptor-positive breast cancer patients (adjusted OR =0.610, P=0.018). Besides, the frequency of the AA genotype was less than that of the GG genotype between the ER-positive breast cancer patients and the controls (adjusted OR =0.791, P=0.038). For rs66916453, which is located in the 3′-UTR of RICTOR, no significant difference was observed between the case and the control group for the genotypes or alleles (P>0.05).

Conclusion

The SNPs in the miRNA-binding sites within the 3′-UTR of SULF1 may serve as protective factors against the susceptibility to breast cancer, especially to ER-positive breast cancer in the Chinese population. These SNPs are promising candidate biomarkers to predict the susceptibility of breast cancer and guide the administration of targeted preventive endocrine therapy.

Restoration of epigenetically silenced SULF1 expression by 5-aza-2-deoxycytidine sensitizes hepatocellular carcinoma cells to chemotherapy-induced apoptosis

Background

Hepatocellular carcinoma (HCC) is the second most frequent cause of cancer death worldwide. Sulfatase 1 (SULF1) functions as a tumor suppressor in HCC cell lines in vitro but also has an oncogenic effect in some HCCs in vivo.

Aim

The purpose of this study was to examine the mechanisms regulating SULF1 and its function in HCC.

Methods

First, SULF1 mRNA and protein expression were examined. Second, we examined SULF1 gene copy numbers in HCC cells. Third, we assessed whether DNA methylation or methylation and/or acetylation of histone marks on the promoter regulate SULF1 expression. Finally, we examined the effect of 5-aza-2′-deoxycytidine (5-Aza-dC) on sulfatase activity and drug-induced apoptosis.

Results

SULF1 mRNA was downregulated in nine of eleven HCC cell lines, but only in six of ten primary tumors. SULF1 mRNA correlated with protein expression. Gene copy number assessment by fluorescence in situ hybridization showed intact SULF1 alleles in low-SULF1-expressing cell lines. CpG island methylation in the SULF1 promoter and two downstream CpG islands did not show an inverse correlation between DNA methylation and SULF1 expression. However, chromatin immunoprecipitation showed that the SULF1 promoter acquires a silenced chromatin state in low-SULF1-expressing cells through an increase in di/trimethyl-K9H3 and trimethyl-K27H3 and a concomitant loss of activating acetyl K9, K14H3 marks. 5-Aza-dC restored SULF1 mRNA expression in SULF1-negative cell lines, with an associated increase in sulfatase activity and sensitization of HCC cells to cisplatin-induced apoptosis.

Conclusion

SULF1 gene silencing in HCC occurs through histone modifications on the SULF1 promoter. Restoration of SULF1 mRNA expression by 5-Aza-dC sensitized HCC cells to drug-induced apoptosis.

SULF1/SULF2 splice variants differentially regulate pancreatic tumour growth progression

This study highlights the highly dynamic nature of SULF1/SULF2 splice variants in different human pancreatic cancers that regulate the activities of multiple cell signalling pathways in development and disease. Most pancreatic tumours expressed variable levels of both SULF1 and SULF2 variants including some expression during inflammation and pancreatitis. Many ductal and centro-acinar cell-derived pancreatic tumours are known to evolve into lethal pancreatic ductal adenocarcinomas but the present study also detected different stages of such tumour progression in the same tissue biopsies of not only acinar cell origin but also islet cell-derived cancers. The examination of caerulein-induced pancreatic injury and tumorigenesis in a Kras-driven mouse model confirmed the activation and gradual increase of SULF1/SULF2 variants during pancreatitis and tumorigenesis but with reduced levels in Stat3 conditional knockout mice with reduced inflammation. The significance of differential spatial and temporal patterns of specific SULF1/SULF2 splice variant expression during cancer growth became further apparent from their differential stimulatory or inhibitory effects on growth factor activities, tumour growth and angiogenesis not only during in vitro but also in vivo growth thus providing possible novel therapeutic targets.