SULF2 Expression Is a Potential Diagnostic and Prognostic Marker in Lung Cancer

The immune cells have complex causal regulation effects on cancers

BACKGROUND

There was a large body of evidence linking immune cells to cancer risk. However, the causal relationship between immune cells, cancer, and what genes play an important role is unclear.

METHODS

In this study, we performed comprehensive two-sample Mendelian randomization analysis (TSMR) to determine the causal relationship between immune cells and common cancers. We also performed Multimarker Analysis of Genomic Annotation (MAGMA) on immune cells causally associated with cancer to identify their relevant genes and used data summary-based MR (SMR) analysis to investigate the causal relationship between their gene expression, methylation, and cancer, and further used drug prediction and molecular docking to validate the medicinal value of the targets. Finally, reverse TSMR analysis was performed on cancer and immune cells to rule out reverse causality.

RESULTS

After FDR correction (PFDR < 0.05), the results showed that 2 immune cells were associated with lung cancer risk, and 1 immune cell was significantly associated with pancreatic cancer risk. The expression of OSBPL10, CHD4, SMDT1, PHETA2, and NAGA was positively and causally related to the risk of lung cancer by SMR analysis and HEIDI test. We also found that increased expression of ANP32E decreased the risk of pancreatic cancer and that the methylation level of OSBPL10, CHD4, SULF2, CENPM, and CYP2D6 had a causal association with lung cancer. The methylation level of FCGR3A was causally associated with pancreatic cancer. The results of molecular docking indicated a strong affinity between the drugs and proteins that possessed existing structural information.

CONCLUSION

This data-driven Mendelian randomization (MR) study demonstrates the causal role of immune cells in cancers. In addition, this study identifies candidate genes that may be potential anti-cancer drug targets.

Human extracellular sulfatases use a dual mechanism for regulation of growth factor interactions with heparan sulfate proteoglycans

Membrane-associated heparan sulfate (HS) proteoglycans (PGs) contribute to the regulation of extracellular cellular signaling cues, such as growth factors (GFs) and chemokines, essential for normal organismal functions and implicated in various pathophysiologies. PGs accomplish this by presenting high affinity binding sites for GFs and their receptors through highly sulfated regions of their HS polysaccharide chains. The composition of HS, and thus GF-binding specificity, are determined during biosynthetic assembly prior to installation at the cell surface. Two extracellular 6- O -endosulfatase enzymes (Sulf-1 and Sulf-2) can uniquely further edit mature HS and alter its interactions with GFs by removing specific sulfation motifs from their recognition sequence on HS. Despite being implicated as signaling regulators during development and in disease, the Sulfs have resisted structural characterization, and their substrate specificity and effects on GF interactions with HS are still poorly defined. Using a panel of PG-mimetics comprising compositionally-defined bioengineered recombinant HS (rHS) substrates in combination with GF binding and enzyme activity assays, we have discovered that Sulfs control GF-HS interactions through a combination of catalytic processing and competitive blocking of high affinity GF-binding sites, providing a new conceptual framework for understanding the functional impact of these enzymes in biological context. Although the contributions from each mechanism are both Sulf- and GF-dependent, the PG-mimetic platform allows for rapid analysis of these complex relationships.

Significance Statement

Cells rely on extracellular signals such as growth factors (GFs) to mediate critical biological functions. Membrane-associated proteins bearing negatively charged heparan sulfate (HS) sugar chains engage with GFs and present them to their receptors, which regulates their activity. Two extracellular sulfatase (Sulf) enzymes can edit HS and alter GF interactions and activity, although the precise mechanisms remain unclear. By using chemically defined HS-mimetics as probes, we have discovered that Sulfs can modulate HS by means of catalytic alterations and competitive blocking of GF-binding sites. These unique dual activities distinguish Sulfs from other enzymes and provide clues to their roles in development and disease.

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.

Identification of key genes in cutaneous squamous cell carcinoma: a transcriptome sequencing and bioinformatics profiling study

Background

Long-term exposure to ultraviolet (UV) radiation can cause cutaneous squamous cell carcinoma (cSCC), which is one of the most common malignant cancers worldwide. Actinic keratosis (AK) is generally considered a precancerous lesion of cSCC. However, the pathogenesis and oncogenic processes of AK and cSCC remain elusive, especially in the context of photodamage.

Methods

In this study, transcriptome sequencing was performed on AK, cSCC, normal sun-exposed skin (NES) tissues, and normal non-sun-exposed skin (NNS) from 24 individuals. Bioinformatics analysis to identify the differentially expressed genes (DEGs) of 4 groups, and potential key genes of cSCC were validated by real-time quantitative reverse transcription PCR (qRT-PCR).

Results

A total of 46,930 genes were differentially expressed in the 4 groups, including 127 genes that were differentially expressed between NES and NNS, 420 DEGs in AK compared to NES, 1,658 DEGs in cSCC compared to NES, and 1,389 DEGs in cSCC compared to AK. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis suggested that the DEGs are involved in multiple pathways, including extracellular matrix (ECM)-receptor interaction, immune, inflammatory, microbial infection, and other related pathways. Finally, 5 new genes (HEPHL1, FBN2, SULF1, SULF2, and TCN1) were confirmed significantly upregulated in cSCC.

Conclusions

Using transcriptome sequencing and integrated bioinformatical analysis, we have identified key DEGs and pathways in cSCC, which could improve our understanding of the cause and underlying molecular events of AK and cSCC. HEPHL1, FBN2, SULF1, SULF2, and TCN1 may be novel potential biomarkers and therapeutic targets of cSCC.

Dendrobine Inhibits γ-Irradiation-Induced Cancer Cell Migration, Invasion and Metastasis in Non-Small Cell Lung Cancer Cells

The use of ionizing radiation (IR) during radiotherapy can induce malignant effects, such as metastasis, which contribute to poor prognoses in lung cancer patients. Here, we explored the ability of dendrobine, a plant-derived alkaloid from Dendrobium nobile, to improve the efficacy of radiotherapy in non-small cell lung cancer (NSCLC). We employed Western blotting, quantitative real-time (qRT)-PCR, transwell migration assays, and wound-healing assays to determine the effects of dendrobine on the migration and invasion of A549 lung cancer cells in vitro. Dendrobine (5 mm) inhibited γ-irradiation-induced migration and invasion of A549 cells by suppressing sulfatase2 (SULF2) expression, thus inhibiting IR-induced signaling. To investigate the inhibitory effects of dendrobine in vivo, we established a mouse model of IR-induced metastasis by injecting BALB/c nude mice with γ-irradiated A549 cells via the tail vein. As expected, injection with γ-irradiated cells increased the number of pulmonary metastatic nodules in mice (0 Gy/DPBS, 9.8 ± 1.77; 2 Gy/DPBS, 20.87 ± 1.42), which was significantly reduced with dendrobine treatment (2 Gy/Dendrobine, 10.87 ± 0.71), by prevention of IR-induced signaling. Together, these findings demonstrate that dendrobine exerts inhibitory effects against γ-irradiation-induced invasion and metastasis in NSCLC cells in vitro and in vivo at non cytotoxic concentrations. Thus, dendrobine could serve as a therapeutic enhancer to overcome the malignant effects of radiation therapy in patients with NSCLC.

Extracellular sulfatases as potential blood-based biomarkers for early detection of lung cancer

PURPOSE

Non-small lung (NSCLC) is the deadliest cancer, with survival measured in months. Earlier diagnosis using a robust biomarker would likely improve survival. This study aims to determine whether blood levels of the extracellular sulfatases (SULF1 and SULF2) and their bio-activity can serve as novel biomarkers for NSCLC early detection.

MATERIALS AND METHODS

Using human plasma specimens from NSCLC patients, nonmalignant COPD patients, and healthy individuals, we determined the association between plasma SULF levels and the presence of NSCLC. We assessed the plasma SULF levels as a function of sex and age. We also evaluated the plasma levels of heparin-binding factors potentially mobilized by the SULFs. To increase test specificity of blood SULF2 as a biomarker for the early diagnosis of NSCLC, we investigated the presence of a tumor-specific SULF2 isoform released in the blood, which could be used as a biomarker alone or in multiplex assays.

RESULTS

The median level of plasma SULF2 was significantly elevated in NSCLC patients than in healthy controls (∼2 fold). However, these data were confounded by age. Surprisingly, COPD patients also showed a dramatically increased SULF2 plasma level. We showed a significant increase in the median plasma levels of several HSPG-binding factors in early-stage NSCLC patients compared to controls. Furthermore, we revealed a significant positive correlation of the SULF2 protein level with the plasma levels of two HSPG-binding factors IL6 and IL8. We demonstrated that NSCLC cancer cells and tissues overexpress a SULF2 splice variant. We determined the presence of a SULF2 splice variant form in NSCLC plasma, which was not detectable in COPD and control plasmas.

CONCLUSION

Our findings highlight the potential for the plasma levels of SULF2 protein and its bio-activity as novel blood biomarkers for early diagnosis of NSCLC.

SULF2 promotes tumorigenesis and inhibits apoptosis of cervical cancer cells through the ERK/AKT signaling pathway

The objective of this study was to explore the role of the SULF2-mediated ERK/AKT signaling pathway in cervical cancer. SULF2 expression was detected in tumor tissues and tumor-adjacent normal tissues from cervical cancer patients. HeLa cells were divided into six groups: control group, NC group, SULF2 siRNA group, SULF2 group, SULF2 + LY294002 group, and SULF2 + U0125 group. In each group, HeLa cells received the corresponding treatment, followed by measurement of the cellular biological characteristics and expression of the ERK/AKT signaling pathway. We also confirmed the effect of SULF2 in vivo using a xenograft model in nude mice. SULF2 was upregulated in cervical cancer tissues, which was specifically associated with the clinical stage, histological differentiation, and lymphatic metastasis. Compared to the control group, the SULF2 siRNA group displayed decreased expression of SULF2, concomitant with reduced proliferation, migration, and invasion, but there was an increase in the apoptosis rate of HeLa cells, as well as downregulation of the p-Akt/Akt, p-ERK/ERK, and Bax/Bcl-2 ratios and cyclin D1. Additionally, tumor growth was significantly inhibited in the xenograft model of nude mice. The results in the SULF2 group were quite the opposite in which SULF2 facilitated the growth of cervical cancer cells, which was reversed by LY294002 or U0126. SULF2 is highly expressed in cervical cancer, and thus, downregulation of SULF2 can inhibit the ERK1/2 and AKT signaling pathways to suppress the proliferation, invasion, and migration of cervical cancer cells while facilitating apoptosis.

Serum microRNA-135a as a diagnostic biomarker in non-small cell lung cancer

The purpose of our research was to evaluate diagnostic performance of serum microRNA-135a (miR-135a) in non-small cell lung cancer (NSCLC).Quantitative real time-polymerase chain reaction was employed to detect the expression serum of miR-135a in NSCLC patients and controls. The influence of serum miR-135a level on clinical characteristics of NSCLC patients was explored through the Chi-square test. Serum carcinoembryonic antigen (CEA) level was estimated via enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) curve was plotted to elucidate diagnostic roles of serum miR-135a and CEA in NSCLC.The expression level of serum miR-135a was significantly lower in NSCLC patients than in healthy controls (0.40 ± 0.29 vs 1.00 ± 0.40, P < .001). Moreover, miR-135a expression was related to lymph node metastasis (P = .021), tumor differentiation (P = .020), and tumor node metastasis stage (P = .031). ROC curve showed serum miR-135a level could discriminate NSCLC patients from healthy controls (P < .0001) with a corresponding cutoff value of 0.665, and a sensitivity and specificity of 81.3% and 83.1%, respectively. The area under the curve was 0.888. In diagnosis analysis on the combination of miR-135a and CEA, when its specificity was maintained at 90%, diagnosis cut-off point reached 0.678.Serum miR-135a level is significantly downregulated in NSCLC and serves as a potential diagnostic biomarker for the disease.

TRF2 positively regulates SULF2 expression increasing VEGF-A release and activity in tumor microenvironment

The telomeric protein TRF2 is overexpressed in several human malignancies and contributes to tumorigenesis even though the molecular mechanism is not completely understood. By using a high-throughput approach based on the multiplexed Luminex X-MAP technology, we demonstrated that TRF2 dramatically affects VEGF-A level in the secretome of cancer cells, promoting endothelial cell-differentiation and angiogenesis. The pro-angiogenic effect of TRF2 is independent from its role in telomere capping. Instead, TRF2 binding to a distal regulatory element promotes the expression of SULF2, an endoglucosamine-6-sulfatase that impairs the VEGF-A association to the plasma membrane by inducing post-synthetic modification of heparan sulfate proteoglycans (HSPGs). Finally, we addressed the clinical relevance of our findings showing that TRF2/SULF2 expression is a worse prognostic biomarker in colorectal cancer (CRC) patients.

Autoantibodies as diagnostic biomarkers for lung cancer: A systematic review

Lung cancer (LC) accounts for the largest number of tumor-related deaths worldwide. As the overall 5-year survival rate of LC is associated with its stages at detection, development of a cost-effective and noninvasive cancer screening method is necessary. We conducted a systematic review to evaluate the diagnostic values of single and panel tumor-associated autoantibodies (TAAbs) in patients with LC. This review included 52 articles with 64 single TAAbs and 19 with 20 panels of TAAbs. Enzyme-linked immunosorbent assays (ELISA) were the most common detection method. The sensitivities of single TAAbs for all stages of LC ranged from 3.1% to 92.9% (mean: 45.2%, median: 37.1%), specificities from 60.6% to 100% (mean: 88.1%, median: 94.9%), and AUCs from 0.416 to 0.990 (mean: 0.764, median: 0.785). The single TAAb with the most significant diagnostic value was the autoantibody against human epididymis secretory protein (HE4) with the maximum sensitivity 91% for NSCLC. The sensitivities of the panel of TAAbs ranged from 30% to 94.8% (mean: 76.7%, median: 82%), specificities from 73% to 100% (mean: 86.8%, median: 89.0%), and AUCs from 0.630 to 0.982 (mean: 0.821, median: 0.820), and the most significant AUC value in a panel (M13 Phage 908, 3148, 1011, 3052, 1000) was 0.982. The single TAAb with the most significant diagnostic calue for early stage LC, was the autoantibody against Wilms tumor protein 1 (WT1) with the maximum sensitivity of 90.3% for NSCLC and its sensitivity and specificity in a panel (T7 Phage 72, 91, 96, 252, 286, 290) were both above 90.0%. Single or TAAbs panels may be useful biomarkers for detecting LC patients at all stages or an early-stage in high-risk populations or health people, but the TAAbs panels showed higher detection performance than single TAAbs. The diagnostic value of the panel of six TAAbs, which is higher than the panel of seven TAAbs, may be used as potential biomarkers for the early detection of LC and can probably be used in combination with low-dose CT in the clinic.

GECKO is a genetic algorithm to classify and explore high throughput sequencing data

Comparative analysis of high throughput sequencing data between multiple conditions often involves mapping of sequencing reads to a reference and downstream bioinformatics analyses. Both of these steps may introduce heavy bias and potential data loss. This is especially true in studies where patient transcriptomes or genomes may vary from their references, such as in cancer. Here we describe a novel approach and associated software that makes use of advances in genetic algorithms and feature selection to comprehensively explore massive volumes of sequencing data to classify and discover new sequences of interest without a mapping step and without intensive use of specialized bioinformatics pipelines. We demonstrate that our approach called GECKO for GEnetic Classification using k-mer Optimization is effective at classifying and extracting meaningful sequences from multiple types of sequencing approaches including mRNA, microRNA, and DNA methylome data.

LncRNA ATB promotes proliferation and metastasis in A549 cells by down-regulation of microRNA-494

Lung cancer is a commonly diagnosed disease with poor prognosis. Novel therapeutic targets and deep understanding of the regulatory mechanisms in lung cancer are of great importance. We aimed to figure out the functional roles of lncRNA-activated by transforming growth factor-β (ATB) in A549 cells as well as the underlying molecular mechanisms. ATB was non-physiologically expressed in A549 cells after cell transfection. Then, cell proliferation, expressions of proteins related to proliferation and epithelial-mesenchymal transition (EMT), migration, and invasion were measured by BrdU incorporation assay, Western blot analysis, and Transwell assay, respectively. Afterwards, miR-494 expression in transfected A549 cells was determined by quantitative reverse transcription PCR. Meanwhile, effects of miR-494 overexpression on ATB-overexpressed cells were assessed. Finally, the phosphorylation levels of AKT and key kinases in the Janus-activated kinase (JAK)/signal transducer and activator of transcription-3 (STAT3) pathway were detected by Western blot analysis. ATB overexpression promoted proliferation, migration, and invasion of A549 cells. Meanwhile, EMT of A549 cells was also enhanced. ATB silence showed the opposite influence. Expression of miR-494 was negatively regulated by ATB. Following experiments showed ATB-induced alterations of proliferation, migration, invasion, and EMT were all reversed by miR-494 overexpression. Finally, we proved that ATB increased phosphorylated levels of AKT, JAK1, and STAT3, and those increases were all reversed by miR-494 overexpression. We interestingly figured out that ATB promoted proliferation, migration, invasion, and EMT through down-regulating miR-494 in A549 cells. Moreover, ATB might activate AKT and the JAK/STAT3 pathway via down-regulating miR-494.

Ratio of Autoantibodies of Tumor Suppressor AIMP2 and Its Oncogenic Variant Is Associated with Clinical Outcome in Lung Cancer

Aminoacyl-tRNA synthetase-interacting multi-functional protein 2 (AIMP2) works as potent tumor suppressor, while its splicing variant lacking exon 2 (AIMP2-DX2) competes with AIMP2 for binding to target proteins and compromises its anti-tumor activity. Assuming that AIMP2 and its variant AIMP2-DX2 could be released out to human sera in pathological condition, we investigated the diagnostic and prognostic usefulness of autoantibodies against AIMP2 and AIMP2-DX2 by measuring their serum levels in 80 normal and lung cancer samples that were matched in age, gender and smoking status. The area under the curve of AIMP2-DX2, AIMP2, and AIMP2-DX2/AIMP2 autoantibody ratio was low (0.416, 0.579, and 0.357, respectively), suggesting limited diagnostic value. A total of 165 lung cancer patients were classified into low and high AIMP2-DX2, AIMP2, and AIMP2-DX2/AIMP2 based on the median expression of each parameter. The high AIMP2-DX2 group was older and had larger tumors (>3 cm) than the low AIMP2-DX2 group. The high AIMP2-DX2/AIMP2 group had higher CYFRA-21 levels and significantly shorter overall survival than the low AIMP2-DX2/AIMP2 group (18.6 vs. 48.9 months, P = 0.021, Log Rank Test). Taken together, autoantibodies against AIMP2-DX2 and AIMP2 are detectable in the human blood and the increased ratio of AIMP2-DX2/AIMP2 is related to poor clinical outcome of lung cancer.

Sulfatase 2 facilitates lymphangiogenesis in breast cancer by regulating VEGF-D

In our previous studies, sulfatase 2 (Sulf2) was found to upregulate vascular endothelial growth factor-D (VEGF-D) expression in breast cancer. As VEGF-D plays an important role in lymphangiogenesis, we hypothesized that Sulf2 facilitates lymphangiogenesis in breast cancer by regulating VEGF-D. To evaluate the functions of Sulf2 on lymphangiogenesis in breast cancer, proliferation, apoptosis, cell cycle, cell mobility and tube-formation of lymphatic endothelial cells (LECs) were measured in vitro. Lymphangiogenesis in nude mouse ears and breast cancer xenografts were examined in vivo. Furthermore, the expression levels of related signaling pathway genes were screened and verified in LECs. We found that Sulf2 significantly increased the mobility and tube formation of the LECs, inhibited cisplatin-induced LEC apoptosis, but had no effect on cell proliferation and the cell cycle. Moreover, recombinant Sulf2 (rSulf2) combined with VEGF-D further promoted the proliferation, cell cycle, mobility and tube-like structure formation in the LECs, and at the same time inhibited cisplatin-induced apoptosis especially in the late stage. Sulf2 also significantly increased the density of lymphatic vessels in mouse ears and breast cancer xenografts in vivo. AKT1 was also shown to be upregulated and activated by Sulf2. Our results confirmed that Sulf2 facilitated lymphangiogenesis in breast cancer cells by regulating VEGF-D and that the AKT1-related signaling pathway was involved.

Multi-omics approach to infer cancer therapeutic targets on chromosome 20q across tumor types

The identification of good targets is a critical step for the development of targeted therapies for cancer treatment. Here, we used a multi-omics approach to delineate potential targets on chromosome 20q, which frequently shows a complex pattern of DNA copy number amplification in many human cancers suggesting the presence of multiple driver genes. By comparing the amounts of individual mRNAs in cancer from 11 different human tissues with those in their corresponding normal tissues, we identified 18 genes that were robustly elevated across human cancers. Moreover, we found that higher expression levels of a majority of these genes were associated with poor prognosis in many human cancer types. Using DNA copy number and expression data for all 18 genes obtained from The Cancer Genome Atlas project, we discovered that amplification is a major mechanism driving overexpression of these 18 genes in the majority of human cancers. Our integrated analysis suggests that 18 genes on chromosome 20q might serve as novel potential molecular targets for targeted cancer therapy.