S100A16, a ubiquitously expressed EF-hand protein which is up-regulated in tumors

Resistance to gemcitabine is mediated by the circ_0036627/miR-145/S100A16 axis in pancreatic cancer

The development of gemcitabine (GEM) resistance severely limits the treatment efficacy in pancreatic cancer (PC) and increasing evidence highlights the vital roles of circular RNAs (circRNAs) in the tumorigenesis, progression and drug resistance of PC. However, the circRNAs underlying GEM resistance development of PC remains to be clarified. The current research aims to unveil the roles of circ_0036627 in dictating the aggressiveness and GEM sensitivity in PC. We reported the increased expression of circ_0036627 in PC tissues and PC cell lines. Elevated circ_0036627 expression level was correlated with advanced tumour grade and poor overall survival in PC patients. Functional assays and in vivo experiments demonstrated that circ_0036627 overexpression was required for the proliferation, migration invasion and GEM resistance in PC cells. circ_0036627 knockdown suppressed tumour development in vivo. The molecular analysis further showed that circ_0036627 increased S100A16 expression by sponging microRNA-145 (miR-145), a tumour-suppressive miRNA that could significantly attenuate PC cell proliferation, migration, invasion and GEM resistance. Furthermore, our findings suggested that S100A16 acted as an oncogenic factor to promote aggressiveness and GEM resistance in PC cells. In conclusion, the current findings provide new mechanistic insights into PC aggressiveness and GEM resistance, suggesting the critical role of circ_0036627/miR-145/S100A16 axis in PC progression and drug resistance development and offering novel therapeutic targets for PC therapy.

Expression and gene regulatory network of S100A16 protein in cervical cancer cells based on data mining

S100A16 protein belongs to the S100 family of calcium-binding proteins, which is widely distributed in human tissues and highly conserved. S100 calcium-binding proteins possess broad biological functions, such as cancer cell proliferation, apoptosis, tumor metastasis, and inflammation (Nat Rev Cancer 15:96-109, 2015). The S100A16 protein was initially isolated from a cell line derived from astrocytoma. The S100A16 protein, consisting of 103 amino acids, is a small acidic protein with a molecular weight of 11,801.4 Da and an isoelectric point (pI) of 6.28 (Biochem Biophys Res Commun 313:237-244, 2004). This protein exhibits high conservation among mammals and is widely expressed in various human tissues (Biochem Biophys Res Commun 322:1111-1122, 2004). Like other S100 proteins, S100A16 contains two EF-hand motifs that form a helix-loop-helix structural domain. The N-terminal domain and the C-terminal domain of S100A16 are connected by a "hinge" linker.S100A16 protein exhibits distinct characteristics that distinguish it from other S100 proteins. A notable feature is the presence of a single functional Ca2 + binding site located in the C-terminal EF-hand, consisting of 12 amino acids per protein monomer (J Biol Chem 281:38905-38917, 2006). In contrast, the N-terminal EF-hand of S100A16 comprises 15 amino acids instead of the typical 14, and it lacks the conserved glutamate residue at the final position. This unique attribute may contribute to the impaired Ca2 + binding capability in the N-terminal region (J Biol Chem 281:38905-38917, 2006). Studies have shown an integral role of S100 calcium-binding proteins in the diagnosis, treatment, and prognosis of certain diseases (Cancers 12:2037, 2020). Abnormal expression of S100A16 protein is implicated in the progression of breast and prostate cancer, but an inhibitor of oral cancer and acute lymphoblastic leukemia tumor cell proliferation (BMC Cancer 15:53, 2015; BMC Cancer 15:631, 2015). Tu et al. (Front Cell Dev Biol 9:645641, 2021) indicate that the overexpression of S100A16 mRNA in cervical cancer(CC) such as cervical squamous cell carcinoma and endocervical adenocarcinoma as compared to the control specimens. Tomiyama N. and co-workers (Oncol Lett 15:9929-9933, 2018) (Tomiyama, N) investigated the role of S100A16 in cancer stem cells using Yumoto cells (a CC cell line),The authors found upregulation of S100A16 in Yumoto cells following sphere formation as compared to monolayer culture.Despite a certain degree of understanding, the exact biological function of S100A16 in CC is still unclear. This article explores the role of S100A16 in CC through a bioinformatics analysis. Referencing the mRNA expression and SNP data of cervical cancer available through The Cancer Genome Atlas (TCGA) database, we analyzed S100A16 and its associated regulatory gene expression network in cervical cancer. We further screened genes co-expressed with S100A16 to hypothesize their function and relationship to the S100A16 cervical cancer phenotype.Our results showed that data mining can effectively elucidate the expression and gene regulatory network of S100A16 in cervical cancer, laying the foundation for further investigations into S100A16 cervical tumorigenesis.

Expression of S100A16 Is Associated with Biological Aggressiveness and Poor Prognosis in Patients with Bladder Cancer Who Underwent Radical Cystectomy

S100 calcium binding protein A16 (S100A16) is expressed in various cancers; however, there are few reports on S100A16 in bladder cancer (BC). We retrospectively investigated clinical data including clinicopathological features in 121 patients with BC who underwent radical cystectomy (RC). Immunohistochemical staining was performed to evaluate S100A16 expression in archived specimens. Cases with >5% expression and more than moderate staining intensity on cancer cells were considered positive. S100A16 expression was observed in 54 patients (44.6%). Univariate analysis showed that S100A16 expression was significantly associated with age, pT stage, recurrence, and cancer-specific death. Kaplan-Meier analyses showed that patients with S100A16 expression had shorter overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) than those without S100A16 expression. In multivariate analysis, pT stage was an independent prognostic factor for OS and lymph node metastasis for CSS and RFS. S100A16 expression may be a biomarker of a biologically aggressive phenotype and poor prognosis in patients with BC who underwent RC. The PI3k/Akt signaling pathway is probably associated with S100A16 and may be a therapeutic target.

An Update on S100A16 in Human Cancer

S100A16 is a member of the S100 protein family. S100A16 is expressed in a variety of human tissues, although at varying levels. S100A16 expression is especially high in tissues rich in epithelial cells. mRNA and protein levels of S100A16 have been reported to be differentially expressed in the majority of human cancers. Functionally, S100A16 has been linked to several aspects of tumorigenesis, for example, cell proliferation, differentiation, migration, invasion, and epithelial-mesenchymal transition (EMT). Accordingly, S100A16 has been suggested to have both tumour-promoting and suppressive roles in human cancers. S100A16-mediated cellular functions are suggested to be mediated by the regulation of various signaling pathways/proteins including EMT-related proteins E-cadherin and Vimentin, PI3K-AKT, p53, MMP1-1, MMP-2, MMP-9, JNK/p38, etc. In addition to the functional roles, expression of S100A16 has been suggested to have prognostic potential in various cancer types. The aims of this review are to summarise the expression profile, identify common molecular partners and functional roles, and explore the prognostic potential of S100A16 in human cancers.

New progress with calcium-binding protein S100A16 in digestive system disease

INTRODUCTION

This review summarizes and analyzes the abnormal expression and mechanism of S100A16 in digestive system diseases, which is expected to provide new ideas and methods for adjuvant treatment and prognosis evaluation of digestive system diseases.

AREAS COVERED

Based on original publications found in database systems (PubMed, Cochrane), we introduce the mechanism and research progress of S100A16 in digestive system tumors, inflammatory bowel disease and fatty liver.

EXPERT OPINION

S100A16 is closely related to the proliferation, migration, and invasion of digestive system tumor cells. Further, it plays an important role in inflammatory bowel disease and fatty liver.

RAGE Inhibitors for Targeted Therapy of Cancer: A Comprehensive Review

The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin family that is overexpressed in several cancers. RAGE is highly expressed in the lung, and its expression increases proportionally at the site of inflammation. This receptor can bind a variety of ligands, including advanced glycation end products, high mobility group box 1, S100 proteins, adhesion molecules, complement components, advanced lipoxidation end products, lipopolysaccharides, and other molecules that mediate cellular responses related to acute and chronic inflammation. RAGE serves as an important node for the initiation and stimulation of cell stress and growth signaling mechanisms that promote carcinogenesis, tumor propagation, and metastatic potential. In this review, we discuss different aspects of RAGE and its prominent ligands implicated in cancer pathogenesis and describe current findings that provide insights into the significant role played by RAGE in cancer. Cancer development can be hindered by inhibiting the interaction of RAGE with its ligands, and this could provide an effective strategy for cancer treatment.

S100a16 deficiency prevents hepatic stellate cells activation and liver fibrosis via inhibiting CXCR4 expression

INTRODUCTION

Liver fibrosis caused by hepatic stellate cells (HSCs) activation is implicated in the pathogenesis of liver diseases. To date, there has been no effective intervention means for this process. S100 proteins are calcium-binding proteins that regulate cell growth and differentiation. This study aimed to investigate whether S100A16 induces HSCs activation and participates in liver fibrosis progression.

METHODS

HSCs were isolated, and the relationship between S100A16 expression and HSCs activation was studied. S100a16 knockdown and transgenic mice were generated and subjected to HSCs activation and liver fibrosis stimulated by different models. Clinical samples were collected for further confirmation. Alterations in gene expression in HSCs were investigated, using transcriptome sequencing to determine the underlying mechanisms.

RESULTS

We observed increased S100A16 levels during HSCs activation. Genetic silencing of S100a16 prevented HSCs activation in vitro. Furthermore, S100a16 silencing exhibited obvious protective effects against HSCs activation and fibrosis progression in mice. In contrast, S100a16 transgenic mice exhibited spontaneous liver fibrosis. S100A16 was also upregulated in the HSCs of patients with fibrotic liver diseases. RNA sequencing revealed that C-X-C motif chemokine receptor 4 (Cxcr4) gene was a crucial regulator of S100A16 induction during HSCs activation. Mechanistically, S100A16 bound to P53 to induce its degradation; this augmented CXCR4 expression to activate ERK 1/2 and AKT signaling, which then promoted HSCs activation and liver fibrosis.

CONCLUSIONS

These data indicate that S100a16 deficiency prevents liver fibrosis by inhibiting Cxcr4 expression. Targeting S100A16 may provide insight into the pathogenesis of liver fibrosis and pave way for the design of novel clinical therapeutic strategies.

The Role of the S100 Protein Family in Glioma

The S100 protein family consists of 25 members and share a common structure defined in part by the Ca²⁺ binding EF-hand motif. Multiple members' dysregulated expression is associated with progression, diagnosis and prognosis in a broad range of diseases, especially in tumors. They could exert wide range of functions both in intracellular and extracellular, including cell proliferation, cell differentiation, cell motility, enzyme activities, immune responses, cytoskeleton dynamics, Ca²⁺ homeostasis and angiogenesis. Gliomas are the most prevalent primary tumors of the brain and spinal cord with multiple subtypes that are diagnosed and classified based on histopathology. Up to now the role of several S100 proteins in gliomas have been explored. S100A8, S100A9 and S100B were highly expression in serum and may present as a marker correlated with survival and prognosis of glioma patients. Individual member was confirmed as a new regulator of glioma stem cells (GSCs) and a mediator of mesenchymal transition in glioblastoma (GBM). Additionally, several members up- or downregulation have been reported to involve in the development of glioma by interacting with signaling pathways and target proteins. Here we detail S100 proteins that are associated with glioma, and discuss their potential effects on progression, diagnosis and prognosis.

S100A16 promotes acute kidney injury by activating HRD1-induced ubiquitination and degradation of GSK3β and CK1α

The pathogenesis of acute kidney injury (AKI) is associated with the activation of multiple signaling pathways, including Wnt/β-catenin signaling. However, the mechanism of Wnt/β-catenin pathway activation in renal interstitial fibroblasts during AKI is unclear. S100 calcium-binding protein A16 (S100A16), a new member of calcium-binding protein S100 family, is a multi-functional signaling factor involved in various pathogenies, including tumors, glycolipid metabolism disorder, and chronic kidney disease (CKD). We investigated the potential participation of S100A16 in Wnt/β-catenin pathway activation during AKI by subjecting wild-type (WT) and S100A16 knockout (S100A16+/−) mice to the ischemia–reperfusion injury (IRI), and revealed S100A16 upregulation in this model, in which knockout of S100A16 impeded the Wnt/β-catenin signaling pathway activation and recovered the expression of downstream hepatocyte growth factor (HGF). We also found that S100A16 was highly expressed in Platelet-derived growth factor receptor beta (PDGFRβ) positive renal fibroblasts in vivo. Consistently, in rat renal interstitial fibroblasts (NRK-49F cells), both hypoxia/reoxygenation and S100A16 overexpression exacerbated fibroblasts apoptosis and inhibited HGF secretion; whereas S100A16 knockdown or Wnt/β-catenin pathway inhibitor ICG-001 reversed these changes. Mechanistically, we showed that S100A16 promoted Wnt/β-catenin signaling activation via the ubiquitylation and degradation of β-catenin complex members, glycogen synthase kinase 3β (GSK3β) and casein kinase 1α (CK1α), mediated by E3 ubiquitin ligase, the HMG-CoA reductase degradation protein 1 (HRD1). Our study identified the S100A16 as a key regulator in the activation of Wnt/β-catenin signaling pathway in AKI.

Downregulated Calcium-Binding Protein S100A16 and HSP27 in Placenta-Derived Multipotent Cells Induce Functional Astrocyte Differentiation

Little is known about genes that induce stem cells differentiation into astrocytes. We previously described that heat shock protein 27 (HSP27) downregulation is directly related to neural differentiation under chemical induction in placenta-derived multipotent stem cells (PDMCs). Using this neural differentiation cell model, we cross-compared transcriptomic and proteomic data and selected 26 candidate genes with the same expression trends in both omics analyses. Those genes were further compared with a transcriptomic database derived from Alzheimer’s disease (AD). Eighteen out of 26 candidates showed opposite expression trends between our data and the AD database. The mRNA and protein expression levels of those candidates showed downregulation of HSP27, S100 calcium-binding protein A16 (S100A16) and two other genes in our neural differentiation cell model. Silencing these four genes with various combinations showed that co-silencing HSP27 and S100A16 has stronger effects than other combinations for astrocyte differentiation. The induced astrocyte showed typical astrocytic star-shape and developed with ramified, stringy and filamentous processes as well as differentiated endfoot structures. Also, some of them connected with each other and formed continuous network. Immunofluorescence quantification of various neural markers indicated that HSP27 and S100A16 downregulation mainly drive PDMCs differentiation into astrocytes. Immunofluorescence and confocal microscopic images showed the classical star-like shape morphology and co-expression of crucial astrocyte markers in induced astrocytes, while electrophysiology and Ca2+ influx examination further confirmed their functional characteristics. In conclusion, co-silencing of S100A16 and HSP27 without chemical induction leads to PDMCs differentiation into functional astrocytes.

Graphical abstract

Expression profiling of S100-proteins in healthy and irreversibly inflamed human dental pulps

AIM

Several S100 proteins have been shown to play an important role in the innate immune response to infection and in regenerative processes. However, they have scarcely been investigated during inflammation of the dental pulp. Therefore, in this study we performed gene expression profiling of S100 proteins in healthy and inflamed human dental pulps.

METHODOLOGY

Tissue samples of human dental pulps were used including fifteen clinically diagnosed as symptomatic irreversible pulpitis (SIP), seven as asymptomatic irreversible pulpitis (AIP), and nineteen as healthy pulp (HP). S100 gene expression levels were quantitatively evaluated for S100 A1, A2, A3, A4, A6, A7, A8, A9, A10, A11, A13, A14, and A16 by qPCR technique. In order to monitor the status of inflammation and degradation of pulp tissues, IL-8, COX-2, and HMGB-1 gene expression was also analysed, with GAPDH serving as reference gene. Differential expression rates for each target gene between SIP, AIP, and HP were evaluated by analysis of variance (ANOVA) followed by Bonferroni post-hoc-test.

RESULTS

Significantly reduced gene expression levels could be detected in SIP compared to HP for S100A1, A2, A3, A4, A6, A10, A13, and for HMGB-1, while gene expression of S100A8, A14, and IL-8 were significantly increased. In AIP, significantly increased expression levels compared to HP were only detected for S100A14, A16, and for IL-8, with other genes of interest not being altered.

CONCLUSIONS

The present study revealed significant differences in gene expression profiles of S100 proteins comparing samples from healthy and inflamed dental pulps. More pronounced differences were observed for symptomatic than for asymptomatic pulpitis.

A Novel S100 Family-Based Signature Associated with Prognosis and Immune Microenvironment in Glioma

Background

Glioma is the most common central nervous system (CNS) cancer with a short survival period and a poor prognosis. The S100 family gene, comprising 25 members, relates to diverse biological processes of human malignancies. Nonetheless, the significance of S100 genes in predicting the prognosis of glioma remains largely unclear. We aimed to build an S100 family-based signature for glioma prognosis.

Methods

We downloaded 665 and 313 glioma patients, respectively, from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) database with RNAseq data and clinical information. This study established a prognostic signature based on the S100 family genes through multivariate COX and LASSO regression. The Kaplan-Meier curve was plotted to compare overall survival (OS) among groups, whereas Receiver Operating Characteristic (ROC) analysis was performed to evaluate model accuracy. A representative gene S100B was further verified by in vitro experiments.

Results

An S100 family-based signature comprising 5 genes was constructed to predict the glioma that stratified TCGA-derived cases as a low- or high-risk group, whereas the significance of prognosis was verified based on CGGA-derived cases. Kaplan-Meier analysis revealed that the high-risk group was associated with the dismal prognosis. Furthermore, the S100 family-based signature was proved to be closely related to immune microenvironment. In vitro analysis showed S100B gene in the signature promoted glioblastoma (GBM) cell proliferation and migration.

Conclusions

We constructed and verified a novel S100 family-based signature associated with tumor immune microenvironment (TIME), which may shed novel light on the glioma diagnosis and treatment.

Proteomic Profile of Saliva in Parkinson's Disease Patients: A Proof of Concept Study

Parkinson's disease (PD) is a progressive neurodegenerative disorder. It affects many organs. Lewy bodies-a histopathological "hallmark" of PD-are detected in about 75% of PD submandibular gland samples. We hypothesize that saliva can be a source of biomarkers of PD. The aim of the study was to evaluate and compare the salivary proteome of PD patients and healthy controls (HC). Salivary samples from 39 subjects (24 PD patients, mean age 61.6 ± 8.2; 15 HC, mean age 60.9 ± 6.7) were collected. Saliva was collected using RNA-Pro-Sal kits. Label-free LC-MS/MS mass spectrometry was performed to characterize the proteome of the saliva. IPA analysis of upstream inhibitors was performed. A total of 530 proteins and peptides were identified. We observed lower concentrations of S100-A16, ARP2/3, and VPS4B in PD group when compared to HC. We conclude that the salivary proteome composition of PD patients is different than that of healthy controls. We observed a lower concentration of proteins involved in inflammatory processes, exosome formation, and adipose tissue formation. The variability of expression of proteins between the two groups needs to be considered.

S100A16 suppresses the proliferation, migration and invasion of colorectal cancer cells in part via the JNK/p38 MAPK pathway

S100 calcium binding protein A16 (S100A16) is the most recent member of the S100 calcium-binding protein family. The function of S100A16 has been associated with various types of cancer; however, its role in colorectal cancer (CRC) remains unknown. Therefore, the aim of the present study was to investigate the role of S100A16 in CRC progression. The Oncomine dataset used in the current study revealed that the expression of S100A16 was decreased in CRC compared with normal colorectal tissues. Similar results were also determined via immunohistochemistry. In addition, a negative association was identified between S100A16 expression and the prognosis of patients with CRC. Further functional experiments revealed that S100A16 knockdown promoted the proliferation, migration and invasion of HCT116 and SW480 cells, and vice versa in Lovo cells. Epithelial-mesenchymal transition (EMT) was promoted and the JNK/p38 MAPK pathway was activated in HCT116 cells following S100A16 knockdown, as determined via western blotting. Furthermore, S100A16 silencing promoted the migration and invasion of cells. EMT was also reversed when cells were treated with the JNK inhibitor (SP600125) or the p38 inhibitor (SB203580). In summary, the results of the present study demonstrated that S100A16 suppressed the proliferation, migration and invasion of CRC cells partially via the JNK/p38 MAPK signalling pathway and subsequent EMT mediation.

Interference of S100A16 suppresses lipid accumulation and inflammation in high glucose-induced HK-2 cells

PURPOSE

Diabetic nephropathy (DN) is a major complication of diabetic mellitus and usually leads to the end-stage renal disease. Inflammation-induced lipid disorders have been proposed to play an important role in the pathogenesis of DN. S100A16 is a novel adipogenic factor, but has not been investigated in DN. This study aims to explore the role of S100A16 in high glucose (HG)-induced HK-2 cells.

METHODS

CCK-8 assay was used to detect cell viability. Cell transfection was performed to knockdown S100A16. Oil red staining was performed to assay lipid accumulation. qRT-PCR and western blotting were conducted to examine corresponding gene expression. Intracellular cholesterol was determined by enzymatic assay. Inflammatory cytokines production was measured using ELISA kits.

RESULTS

The results exhibited lipid accumulation and upregulation of S100A16 in HG-induced HK-2 cells. S100A16 knockdown significantly reduced lipid droplets and cholesterol, and decreased the production of inflammatory cytokines induced by HG. Besides, S100A16 knockdown decreased the expression of SCAP, SREBP1, SCD1 and SCAP. However, the inhibitory effect in HG-induced HK-2 cells made by S100A16 was reversed by SREBP1 overexpression.

CONCLUSION

These results suggested that S100A16 knockdown might protect against HG-induced lipid accumulation and inflammation in HK-2 cells through regulating SCAP/SREBP1 signaling.

S100A16 promotes metastasis and progression of pancreatic cancer through FGF19-mediated AKT and ERK1/2 pathways

The S100 protein family genes play a crucial role in multiple stages of tumorigenesis and progression. Most of S100 genes are located at chromosome locus 1q21, which is a region frequently rearranged in cancers. Here, we examined the expression of the S100 family genes in paired pancreatic ductal adenocarcinoma (PDAC) samples and further validated the expression of S100A16 by immunohistochemistry staining. We found that S100A16 is significantly upregulated in clinical PDAC samples. However, its roles in PDAC are still unclear. We next demonstrated that S100A16 promotes PDAC cell proliferation, migration, invasion, and metastasis both in vitro and in vivo. Knockdown of S100A16 induces PDAC cell cycle arrest in the G2/M phase and apoptosis. Furthermore, we also demonstrated that S100A16 promotes PDAC cell proliferation, migration, and invasion via AKT and ERK1/2 signaling in a fibroblast growth factor 19 (FGF19)-dependent manner. Taken together, our results reveal that S100A16 is overexpressed in PDAC and promotes PDAC progression through FGF19-mediated AKT and ERK1/2 signaling, suggesting that S100A16 may be a promising therapeutic target for PDAC. S100A16 was upregulated in PDAC and associated with prognosis of PDAC patients. S100A16 regulates apoptosis and the cell cycle of pancreatic cancer cells. S100A16 promotes the progression of pancreatic cancer by AKT-ERK1/2 signaling. S100A16 may be a promising therapeutic target for PDAC.

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

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

Single cell sequencing reveals cell populations that predict primary resistance to imatinib in chronic myeloid leukemia

The treatment of chronic myeloid leukemia (CML), a disease caused by t(9;22)(q34;q11) reciprocal translocation, has advanced largely through the use of targeted tyrosine kinase inhibitors (TKIs). To identify molecular differences that might distinguish TKI responders from non-responders, we performed single cell RNA sequencing on cells (n = 41,723 cells) obtained from the peripheral blood of four CML patients at different stages of treatment to generate single cell expression profiles. Analysis of our single cell expression profiles in conjunction with those previously obtained from the bone marrow of additional CML patients and healthy donors (total = 69,263 cells) demonstrated that imatinib treatment significantly altered leukocyte population compositions in both responders and non-responders, and affected the expression profiles of multiple cell populations, including non-neoplastic cell types. Notably, in imatinib poor-responders, patient-specific pre-treatment unique stem/progenitor cells became enriched in peripheral blood compared to the responders. These results indicate that resistance to TKIs might be intrinsic in some CML patients rather than acquired, and that non-neoplastic immune cell types may also play vital roles in dispersing the responsiveness of patients to TKIs. Furthermore, these results demonstrated the potential utility of peripheral blood as a diagnostic tool in the TKI sensitivity of CML patients.

Identification of cellular inhibitors against Chikungunya virus replication by a cDNA expression cloning combined with MinION sequencing

cDNA expression cloning has been shown to be a powerful approach in the search for cellular factors that control virus replication. In this study, cDNA library screening using a pool of cDNA derived from interferon-treated human cells was combined with the MinION sequencer to identify cellular genes inhibiting Chikungunya virus (CHIKV) replication. Challenge infection of CHIKV to Vero cells transduced with the cDNA library produced virus-resistant cells. Then, the MinION sequence of cDNAs extracted from the surviving cells revealed that the open reading frames of TOM7, S100A16, N-terminally truncated form of ECI1 (ECI1ΔN59), and RPL29 were inserted in many of the cells. Importantly, the transient expression of TOM7, S100A16, and ECI1ΔN59 was found to inhibit the replication of CHIKV in Huh7 cells, indicating that these cellular factors were potentially anti-CHIKV molecules. Thus, our study demonstrated that cDNA expression cloning combined with the MinION sequencer allowed a rapid and comprehensive detection of cellular inhibitors against CHIKV.

Identification of Prognostic Immune-Related Genes by Integrating mRNA Expression and Methylation in Lung Adenocarcinoma

Background

There is plenty of evidence showing that immune-related genes (IRGs) and epigenetic modifications play important roles in the biological process of cancer. The purpose of this study is to establish novel IRG prognostic markers by integrating mRNA expression and methylation in lung adenocarcinoma (LUAD).

Methods and Results

The transcriptome profiling data and the RNA-seq data of LUAD with the corresponding clinical information of 543 LUAD cases were downloaded from The Cancer Genome Atlas (TCGA) database, which were analyzed by univariate Cox proportional regression and multivariate Cox proportional regression to develop an independent prognostic signature. On the basis of this signature, we could divide LUAD patients into the high-risk, medium-risk, and low-risk groups. Further survival analyses demonstrated that high-risk patients had significantly shorter overall survival (OS) than low-risk patients. The signature, which contains 8 IRGs (S100A16, FGF2, IGKV4-1, CX3CR1, INHA, ANGPTL4, TNFRSF11A, and VIPR1), was also validated by data from the Gene Expression Omnibus (GEO) database. We also conducted analyses of methylation levels of the relevant IRGs and their CpG sites. Meanwhile, their associations with prognosis were examined and validated by the GEO database, revealing that the methylation levels of INHA, S100A16, the CpG site cg23851011, and the CpG site cg06552037 may be used as the potential regulators for the treatment of LUAD.

Conclusion

Collectively, INHA, S100A16, the CpG site cg23851011, and the CpG site cg06552037 are promising biomarkers for monitoring the outcomes of LUAD.

Interaction of calcium binding protein S100A16 with myosin-9 promotes cytoskeleton reorganization in renal tubulointerstitial fibrosis

Renal fibrosis arises by the generation of matrix-producing fibroblasts and myofibroblasts through the epithelial-mesenchymal transition (EMT), a process in which epithelial cells undergo a transition into a fibroblast phenotype. A key feature of the EMT is the reorganization of the cytoskeletons, which may involve the Ca²⁺-binding protein S100A16, a newly reported member of the S100 protein family. However, very few studies have examined the role of S100A16 in renal tubulointerstitial fibrosis. In this study, S100A16 expression was examined by immunohistochemical staining of kidney biopsy specimens from patients with various nephropathies and kidney tissues from a unilateral ureteral obstruction (UUO) mouse model. Renal histological changes were investigated in S100A16^Tg, S100A16^+/-, and WT mouse kidneys after UUO. The expression of epithelia marker E-cadherin, mesenchymal markers N-cadherin, and vimentin, extracellular matrix protein, and S100A16, as well as the organization of F-actin, were investigated in S100A16 overexpression or knockdown HK-2 cells. Mass spectrometry was employed to screen for S100A16 binding proteins in HK-2 cells. The results indicated that S100A16 is high expressed and associated with renal tubulointerstitial fibrosis in patient kidney biopsies and in those from UUO mice. S100A16 promotes renal interstitial fibrosis in UUO mice. S100A16 expression responded to increasing Ca²⁺ and interacted with myosin-9 during kidney injury or TGF-β stimulation to promote cytoskeleton reorganization and EMT progression in renal tubulointerstitial fibrosis. Therefore, S100A16 is a critical regulator of renal tubulointerstitial fibroblast activation and is therefore a potential therapeutic target for the treatment of renal fibrosis.

Integrated nuclear proteomics and transcriptomics identifies S100A4 as a therapeutic target in acute myeloid leukemia

Inappropriate localization of proteins can interfere with normal cellular function and drive tumor development. To understand how this contributes to the development of acute myeloid leukemia (AML), we compared the nuclear proteome and transcriptome of AML blasts with normal human CD34+ cells. Analysis of the proteome identified networks and processes that significantly affected transcription regulation including misexpression of 11 transcription factors with seven proteins not previously implicated in AML. Transcriptome analysis identified changes in 40 transcription factors but none of these were predictive of changes at the protein level. The highest differentially expressed protein in AML nuclei compared with normal CD34+ nuclei (not previously implicated in AML) was S100A4. In an extended cohort, we found that over-expression of nuclear S100A4 was highly prevalent in AML (83%; 20/24 AML patients). Knock down of S100A4 in AML cell lines strongly impacted their survival whilst normal hemopoietic stem progenitor cells were unaffected. These data are the first analysis of the nuclear proteome in AML and have identified changes in transcription factor expression or regulation of transcription that would not have been seen at the mRNA level. These data also suggest that S100A4 is essential for AML survival and could be a therapeutic target in AML.

Genome-wide screening of abberant methylated drivers combined with relative risk loci in bladder cancer

Background

To explore important methylation‐driven genes (MDGs) and risk loci to construct risk model for prognosis of bladder cancer (BCa).

Methods

We utilized TCGA‐Assembler package to download 450K methylation data and corresponding transcriptome profiles. MethylMix package was used for identifying methylation‐driven genes and functional analysis was mainly performed based on ConsensusPathDB database. Then, Cox regression method was utilized to find prognostic MDGs, and we selected 17 hub genes via stepwise regression and multivariate Cox models. Kruskal‐Wallis test was implemented for comparisons between risk with other clinical variables. Moreover, we constructed the risk model and validated it in http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE13507. Gene set enrichment analysis was performed using the levels of risk score as the phenotype. Additionally, we further screened out the relative methylation sites associated with the 17 hub genes. Cox regression and Survival analysis were conducted to find the specifically prognostic sites.

Results

Two hundred and twenty‐eight MDGs were chosen by ConsensusPathDB database. Results revealed that most conspicuous pathways were transcriptional mis‐regulation pathways in cancer and EMT. After Cox regression analysis, 17 hub epigenetic MDGs were identified. We calculated the risk score and found satisfactory predictive efficiency by ROC curve (AUC = 0.762). In the validation group from http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE13507, 17 hub genes remained higher predictive value with AUC = 0.723 and patients in high‐risk group. Meanwhile, Kruskal‐Wallis test revealed that higher risk score correlated with a higher level of TNM stage, tumor grade, and advanced pathological stages. Then, identified 38 risk methylated loci that highly associated with prognosis. Last, gene set enrichment analysis revealed that high‐risk level of MDGs may correlate with several important pathways, including MAPK signaling pathway and so on.

Conclusion

Our study indicated several hub‐MDGs, calculated novel risk score and explored the prognostic value in BCa, which provided a promising approach to BCA prognosis assessment.

S100A16-induced adipogenesis is associated with up-regulation of 11 β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)

The steadily increasing epidemic of obesity continues at alarming rates, is an important public health problem, and expression changes of S100A16 and 11 β-hydroxysteroid dehydrogenase type 1(11β-HSD1) is attributable to the adipocyte differentiation. In our previous study, we found that 11β-HSD1 protein expression increased in S100A16-overexpressed 3T3-L1 cell model. In order to further investigate the relationship between S100A16 and 11β-HSD1, and the molecular mechanisms of S100A16-induced adipogenesis, we constructed S100A16 transgenic and knockout mouse, and S100A16-overexpressed 3T3-L1 preadipocyte cell. Using S100A16 transgenic (S100A16Tg/+) mice fed with normal fat diet (NFD) and high fat diet (HFD) diet model, we evaluated the effect of S100A16 on adipogenesis, expression of 11β-HSD1, and RNA sequencing and quantification of gene expression. Using the 3T3-L1 cell model, we examined the effect of S100A16 and 11β-HSD1 on pre-adipocyte differentiation, and cell signaling events of 11β-HSD1 overexpression induced by S100A16. We found that when compared with C57BL/6 mice, overexpression of S100A16 under the condition of HFD increased lipid content in WAT and fat infiltration in hepatocytes, 11β-HSD1 protein expression increased along with S100A16. Elevated S100A16 and 11β-HSD1 expression promoted adipogenesis in 3T3-L1 cells. Overexpression of S100A16 inhibited the degradation of 11β-HSD1. We conclude that S100A16-induced adipogenesis is associated with up-regulation of 11β-HSD1.

S100A16 regulated by Snail promotes the chemoresistance of nonmuscle invasive bladder cancer through the AKT/Bcl-2 pathway

Objective: To fully investigate the effect of S100 proteins on the chemoresistance of nonmuscle invasive bladder cancer (NMIBC).

Materials and methods: The mitomycin C-resistant bladder cancer cell line M-RT4 was established and liquid chromatography-tandem mass spectrometry was performed for proteomics analysis. RT-PCR and Western blot were then performed to confirm the findings. To investigate the mechanisms, S100A16 was knocked down by siRNA. Then, the sensitivity of M-RT4 to mitomycin C was analyzed by a cell counting kit-8 (CCK8) assay, and the molecular expression including epithelial-mesenchymal transition (EMT)-related and apoptosis-related markers were also examined by Western blot. Based on the cancer genome atlas (TCGA) data, the prognostic value of S100A16 was also investigated.

Results: There were six S100 proteins with differential expression, among which S100A16 was confirmed to be the only upregulated protein in M-RT4 cells. The expression of S100A16 was regulated by the EMT-related transcription factor Snail. Knockdown of S100A16 suppressed the AKT/Bcl-2 pathway to promote apoptosis, greatly sensitizing M-RT4 cells to mitomycin C. The expression of S100A16 was negatively correlated with the overall survival of bladder cancer patients.

Conclusion: S100A16 contributes to the chemoresistance of NMIBC by promoting the AKT/Bcl-2-mediated anti-apoptosis effect and could be a potential prognostic marker and therapeutic target for NMIBC patients.

Prognostic values of S100 family members in ovarian cancer patients

Objective

Exhibiting high consistence in sequence and structure, S100 family members are interchangeable in function and they show a wide spectrum of biological processes, including proliferation, apoptosis, migration, inflammation and differentiation and the like. While the prognostic value of each individual S100 in ovarian cancer is still elusive. In current study, we investigated the prognostic value of S100 family members in the ovarian cancer.

Methods

We used the Kaplan Meier plotter (KM plotter) database, in which updated gene expression data and survival information are from 1657 ovarian cancer patients, to assess the relevance of individual S100 family mRNA expression to overall survival in various ovarian cancer subtypes and different clinicopathological features.

Results

It was found that high expression of S100A2 (HR = 1.18, 95%CI: 1.04–1.34, P = 0.012), S100A7A (HR = 1.3, 95%CI: 1.04–1.63, P = 0.02),S100A10 (HR = 1.2, 95%CI: 1.05–1.38, P = 0.0087),and S100A16 (HR = 1.23, 95%CI: 1–1.51, P = 0.052) were significantly correlated with worse OS in all ovarian cancer patients, while the expression of S100A1 (HR = 0.87, 95%CI: 0.77–0.99, P = 0.039), S100A3 (HR = 0.83, 95%CI: 0.71–0.96, P = 0.0011), S100A5 (HR = 0.84, 95%CI: 0.73–0.97, P = 0.017), S100A6 (HR = 0.84, 95%CI: 0.72–0.98, P = 0.024), S100A13 (HR = 0.85, 95%CI:0.75–0.97, P = 0.014) and S100G (HR = 0.86, 95%CI: 0.74–0.99, P = 0.041) were associated with better prognosis. Furthermore, we assessed the prognostic value of S100 expression in different subtypes and the clinicopathological features, including pathological grades, clinical stages and TP53 mutation status, of ovarian cancer patients.

Conclusion

Comprehensive understanding of the S100 family members may have guiding significance for the diagnosis and outcome of ovarian cancer patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5170-3) contains supplementary material, which is available to authorized users.

Aberrant S100A16 expression might be an independent prognostic indicator of unfavorable survival in non-small cell lung adenocarcinoma

S100A16 is a conserved member of the S100 protein family in mammals. Its upregulation was observed in many tumors and is related to malignant transformation. In this study, we explored the independent prognostic value of S100A16 in terms of overall survival (OS) and recurrence-free survival (RFS) by performing a retrospective study, using data in The Cancer Genome Atlas (TCGA)-lung adenocarcinoma (LUAD). Besides, by using deep sequencing data in TCGA-LUAD, we also explored the association between S100A16 expression and its DNA methylation and copy number alterations (CNAs). Results showed that the primary LUAD tissues (N = 514) had significantly elevated S100A16 expression compared with the normal lung tissues (N = 59). Based on OS data of 502 primary LUAD cases, we found that high S100A16 expression was correlated with inferior OS. The following univariate and multivariate analysis confirmed that increased S100A16 expression was an independent prognostic indicator of unfavorable OS (HR: 1.197, 95%CI: 1.050–1.364, p = 0.007) and RFS (HR: 1.206, 95%CI: 1.045–1.393, p = 0.011). By examining the DNA methylation data in TCGA-LUAD, we found that some S100A16 DNA CpG sites were generally hypermethylated in normal tissues, but not in LUAD tissues. Regression analysis identified a moderately negative correlation between S100A16 expression and its DNA methylation. In comparison, although DNA amplification (+1/+2) was frequent (378/511, 74%) in LUAD patients, it was not associated with increased S100A16 expression. Based on findings above, we infer that aberrant S100A16 expression might be modulated by its DNA hypomethylation and serves as an independent prognostic indicator of unfavorable OS and RFS in LUAD.

S100A16 up-regulates Oct4 and Nanog expression in cancer stem-like cells of Yumoto human cervical carcinoma cells

Cancer stem-like cells (CSCs), which possess the ability to self-renewal and are multipotent, are regarded as the cause of tumor formation, recurrence, metastasis and drug resistance. It is necessary to understand the properties of CSCs in order to treat them effectively. It has been previously reported that S100 family proteins, which carry calcium-binding EF-hand motifs and are associated with tumorigenic processes, serve crucial roles in maintaining cancer stem-like properties. S100A16 is upregulated in various types of cancer, including bladder, lung and pancreatic. However, the roles of S100A16 in cancer cells, particularly CSCs, are not clear. The present study investigated the roles of S100A16 in CSCs using the sphere formation assay of Yumoto cells, which are a human cervical carcinoma cell line. The mRNA expression levels were evaluated by reverse transcription-polymerase chain reaction and the protein expression levels were detected by western blot analysis. Following the sphere formation of Yumoto cells, the mRNA and protein expression level of Oct4, Nanog and S100A16 were increased compared with the control cells. Following transfection with S100A16 small interfering RNA (siRNA), the mRNA and protein expression of Oct4 and Nanog were decreased and the spheroid size was significantly decreased in the sphere formation of Yumoto cells compared with control siRNA treated cells. There was no change in the p53 mRNA expression level, whereas the p53 protein expression level, which was decreased by the sphere formation, was recovered by S100A16 knockdown. In addition, the protein expression levels of Oct4 and Nanog, which were increased in the sphere formation, were decreased by the proteasome inhibitor lactacystin. No differences were observed in the S100A16 protein expression between the presence or absence of lactacystin. These results suggest that S100A16 serves an important role in the CSCs of human cervical carcinoma and is a positive regulator of Oct4 and Nanog.

S100A16, a promising candidate as a prognostic marker for platinum-based adjuvant chemotherapy in resected lung adenocarcinoma

Purpose

Although cisplatin-based adjuvant chemotherapy improves the survival of patients with resected non-small-cell lung cancer, not all patients show a survival benefit, and some patients experience severe toxicity. Therefore, identifying biomarkers is important for selecting subgroups of patients who may show improved survival with platinum-based adjuvant chemotherapy. S100A16 is thought to play key roles during different steps of tumor progression. The aim of this study was to evaluate the use of S100A16 expression as a prognostic marker in patients with completely resected lung adenocarcinoma receiving platinum-based adjuvant chemotherapy.

Methods

S100A16 expression was immunohistochemically studied in 65 consecutive lung adenocarcinoma patients who underwent complete resection and received platinum-based adjuvant chemotherapy. Kaplan–Meier survival analysis and Cox proportional hazards models were used to estimate the effect of S100A16 expression on disease-free survival (DFS) and overall survival (OS).

Results

S100A16 expression was detected in 26 of the 65 (40.0%) lung adenocarcinoma patients. Although S100A16 expression was not correlated with DFS (P=0.062), it was significantly correlated with OS (P=0.009). In addition, multivariable analysis revealed that S100A16 expression independently predicted a poorer survival (HR =4.79; 95% CI =1.87–12.23; P=0.001).

Conclusion

The present study revealed that S100A16 is a promising candidate as a prognostic marker for platinum-based adjuvant chemotherapy in resected lung adenocarcinoma. A further large-scale study is needed to confirm the present results.

S100A16 is a prognostic marker for colorectal cancer

BACKGROUND

S100 is a superfamily of calcium-binding proteins that regulate multiple biological processes and are involved in many diseases. S100A16 has recently been identified to be involved in several cancers such as bladder cancer, lung cancer, and oral squamous cell carcinoma. However, the role of S100A16 expression in the colorectal cancer (CRC) has not been investigated.

METHODS

S100A16 protein expression was detected by immunohistochemistry in 296 cases of CRC. Kaplan-Meier survival analysis and Cox regression analysis were performed to evaluate the prognostic significance of S100A16.

RESULT

The results showed that the overall survival (OS) of patients with low membrane S100A16 expression was significantly shorter than patients with high expression (P < 0.05). Chi-square analysis showed that S100A16 expression had a positive correlation with tumor grade (P = 0.02). Multivariate analysis identified membrane S100A16 expression as an independent prognostic marker for OS in CRC patients. (P < 0.05). Univariate analysis showed no significant association between cytoplasmic/nuclear S100A16 expression and OS.

CONCLUSION

Membrane S100A16 is associated with the prognosis of CRC patients, indicating that S100A16 may be a potential prognostic biomarker and therapeutic target for CRC.

S100A16 promotes cell proliferation and metastasis via AKT and ERK cell signaling pathways in human prostate cancer

S100A16 is a member of the S100 calcium-binding protein family. It is overexpressed in many types of tumors and associated with proliferation, migration, and invasion; however, its function in human prostate cancer is unresolved. Our objective was to determine its effects and the underlying pathways of S100A16 in prostate cancer tissues and cells. We measured S100A16 expression by quantitative real-time polymerase and Western blotting in eight matched prostate cancer and adjacent normal tissues, and in three prostate cancer cell lines, DU-145, LNCaP, and PC-3, compared to a normal prostate epithelial cell line PrEC. DU-145 cells stably overexpressing S100A16 and PC-3 cells with S100A16 knockdown were established by transfection with S100A16 overexpression plasmid or shRNAs. Invasion, migration, and proliferation were analyzed by transwell assay, wound healing, and colony formation assays, respectively. Western blotting and invasion assays were performed to determine expressions and activation of AKT, ERK, p21, and p27. S100A16 was significantly overexpressed in both prostate cancer tissues and cells lines compared to normal controls (P < 0.05). Overexpression of S100A16 significantly promoted invasion, migration, and proliferation in prostate cancer cells in vitro, whereas silencing S100A16 showed the converse effects (P < 0.05). Furthermore, overexpression of S100A16 activated cell signaling proteins AKT and ERK and downregulated tumor suppressors p21 and p27. Specific inhibitors, LY294002 and PD98059, suppressed activation of AKT and ERK, which attenuated DU-145 cell clone formation and invasion induced by S100A16 overexpression. S100A16 may promote human prostate cancer progression via signaling pathways involving AKT, ERK, p21, and p27 downstream effectors. Our findings suggest that S100A16 may serve as a novel therapeutic or diagnostic target in human prostate cancer.

S100A16 promotes differentiation and contributes to a less aggressive tumor phenotype in oral squamous cell carcinoma

Background

Altered expression of S100A16 has been reported in human cancers, but its biological role in tumorigenesis is not fully understood. This study aimed to investigate the clinical significance and functional role of S100A16 in oral squamous cell carcinoma (OSCC) suppression.

Methods

S100A16 mRNA and/or protein levels were examined by quantitative RT-PCR and immunohistochemistry in whole- and laser microdissected-specimens of normal human oral mucosa (NHOM, n = 65), oral dysplastic lesions (ODL, n = 21), OSCCs (n = 132) and positive cervical nodes (n = 17). S100A16 protein expression in OSCC was examined for correlations with clinicopathological variables and patient survival. S100A16 was over-expressed and knocked-down in OSCC-derived (CaLH3 and H357) cells by employing retroviral constructs to investigate its effects on cell proliferation, sphere formation and three dimensional (3D)-organotypic invasive abilities in vitro and tumorigenesis in a mouse xenograft model.

Results

Both S100A16 mRNA and protein levels were found to be progressively down-regulated from NHOM to ODL and OSCC. Low S100A16 protein levels in OSCC significantly correlated with reduced 10-year overall survival and poor tumor differentiation. Analysis of two external OSCC microarray datasets showed a positive correlation between the mRNA expression levels of S100A16 and keratinocyte differentiation markers. CaLH3 and H357 cell fractions enriched for differentiated cells either by lack of adherence to collagen IV or FACS sorting for low p75NTR expression expressed significantly higher S100A16 mRNA levels than the subpopulations enriched for less differentiated cells. Corroborating these findings, retroviral mediated S100A16 over-expression and knock-down in CaLH3 and H357 cells led to respective up- and down-regulation of differentiation markers. In vitro functional studies showed significant reduction in cell proliferation, sphere formation and 3D-invasive abilities of CaLH3 and H357 cells upon S100A16 over-expression. These functional effects were associated with concomitant down-regulation of self-renewal (Bmi-1 and Oct 4A) and invasion related (MMP1 and MMP9) molecules. S100A16 over-expression also suppressed tumorigenesis of H357 cells in a mouse xenograft model and the resulting tumor xenografts displayed features/expression of increased differentiation and reduced proliferation/self-renewal.

Conclusions

These results indicate that S100A16 is a differentiation promoting protein and might function as a tumor suppressor in OSCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1622-1) contains supplementary material, which is available to authorized users.

Co-expression of S100A14 and S100A16 correlates with a poor prognosis in human breast cancer and promotes cancer cell invasion

Background

S100 family proteins have recently been identified as biomarkers in various cancers. Of this protein family, S100A14 and S100A16 are also believed to play an important role in tumor progression. The aim of the present study was to clarify the clinical significance and functional role of these molecules in breast cancer.

Methods

In a clinical study, an immunohistochemical analysis of S100A14 and S100A16 expression in archival specimens of primary tumors of 167 breast cancer patients was performed. The relationship of S100A14 and S100A16 expression to patient survival and clinicopathological variables was statistically analyzed. In an experimental study, the subcellular localization and function of these molecules was examined by using the human breast cancer cell lines MCF7 and SK-BR-3, both of which highly express S100A14 and S100A16 proteins. Cells transfected with expression vectors and siRNA for these genes were characterized using in vitro assays for cancer invasion and metastasis.

Results

Immunohistochemical analysis of 167 breast cancer cases showed strong cell membrane staining of S100A14 (53% of cases) and S100A16 (31% of cases) with a significant number of cases with co-expression (p < 0.001). Higher expression levels of these proteins were significantly associated with a younger age (<60 years), ER-negative status, HER2-positive status and a poorer prognosis. Co-expression of the two proteins showed more aggressive features with poorer prognosis. In the human breast cancer cell lines MCF7 and SK-BR-3, both proteins were colocalized on the cell membrane mainly at cell-cell attachment sites. Immunoprecipitation and immunofluorescence analyses demonstrated that the 100A14 protein can bind to actin localized on the cell membrane in a calcium-independent manner. A Boyden chamber assay showed that S100A14 and S100A16 knockdown substantially suppressed the invasive activity of both cell lines. Cell motility was also inhibited by S100A14 knockdown in a modified dual color wound-healing assay.

Conclusions

To our knowledge, this is the first report showing the correlation of expression of S100A14, S100A16, and co-expression of these proteins with poor prognosis of breast cancer patients. In addition, our findings indicate that S100A14 and S100A16 can promote invasive activity of breast cancer cells via an interaction with cytoskeletal dynamics. S100A14 and S100A16 might be prognostic biomarkers and potential therapeutic targets for breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1059-6) contains supplementary material, which is available to authorized users.

Identification of differentially expressed genes in pituitary adenomas by integrating analysis of microarray data

Pituitary adenomas, monoclonal in origin, are the most common intracranial neoplasms. Altered gene expression as well as somatic mutations is detected frequently in pituitary adenomas. The purpose of this study was to detect differentially expressed genes (DEGs) and biological processes during tumor formation of pituitary adenomas. We performed an integrated analysis of publicly available GEO datasets of pituitary adenomas to identify DEGs between pituitary adenomas and normal control (NC) tissues. Gene function analysis including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) networks analysis was conducted to interpret the biological role of those DEGs. In this study we detected 3994 DEGs (2043 upregulated and 1951 downregulated) in pituitary adenoma through an integrated analysis of 5 different microarray datasets. Gene function analysis revealed that the functions of those DEGs were highly correlated with the development of pituitary adenoma. This integrated analysis of microarray data identified some genes and pathways associated with pituitary adenoma, which may help to understand the pathology underlying pituitary adenoma and contribute to the successful identification of therapeutic targets for pituitary adenoma.

Up-regulation of S100A16 expression promotes epithelial-mesenchymal transition via Notch1 pathway in breast cancer

BACKGROUND

Our previous studies demonstrated that S100A16 promotes adipogenesis and is involved in weight gain attenuation induced by dietary calcium. Till now, the function of S100A16 in the breast cancer remains to be elucidated.

RESULTS

In this study, we observed that S100A16 was expressed in higher levels in human breast cancer tissues compared with paired adjacent non-cancerous tissues. Further examination showed that overexpression of S100A16 in MCF-7 cells could increase cell proliferation and colony formation. One major mechanistic change was that S100A16 was able to up-regulate the transcription factors Notch1, ZEB1, and ZEB2, which had the capacities to directly repress the expression of epithelial markers E-cadherin and β-catenin but increase mesenchymal markers N-cadherin and vimentin, a characterized phenotype of epithelial-mensenchymal transition (EMT). In addition to display with morphologic change, migration and invasion were increased in S100A16 over-expressed MCF-7 cells. Importantly, knockdown of Notch1 by specific siRNA could reverse the EMT induced by S100A16 overexpression, which confirmed that Notch1 played a critical role in the process of EMT induced by S100A16.

CONCLUSIONS

All together, our data indicated that S100A16 had a potential function to regulate some embryonic transcription factors to promote EMT in breast cancer cells which may be an important target site for the therapy of breast cancer.

S100A14 interacts with S100A16 and regulates its expression in human cancer cells

Both S100A14 and S100A16 are members of the multifunctional S100 protein family. Formation of homo/heterodimers is considered to be one of the major mechanisms for S100 proteins to execute their diverse cellular functions. By employing a classical Yeast two hybrid (Y-2 H) screen, we identified S100A16 as the single interaction partner of S100A14. This interaction was verified by co-immunoprecipitation, double indirect immunofluorescence and double immunostaining in specimens of oral squamous cell carcinoma and normal oral mucosa. The functional significance of this interaction was examined by employing retroviral mediated over-expression and knock-down of these proteins in several cancer cell-lines. Over-expression and knock-down of S100A14 led to concomitant up- and down-regulation of S100A16 protein in the cell-lines examined. However, there was no up-regulation of S100A16 mRNA upon S100A14 over-expression, indicating that modulation of S100A16 expression was not due to enhanced transcriptional activity but possibly by post-transcriptional regulation. In contrary, over-expression of S100A16 was associated neither with the up-regulation of S100A14 mRNA nor its protein, suggesting a unidirectional regulation between S100A14 and S100A16. Cellular treatment with protein synthesis inhibitor cycloheximide demonstrated a time-dependent intracellular degradation of both S100A16 and S100A14 proteins. Additionally, regulation of S100A16 and S100A14 degradation was found to be independent of the classical proteasomal and lysosomal pathways of protein degradation. Further studies will therefore be necessary to understand the functional significance of this interaction and the mechanisms on how S100A14 is involved in the regulation of S100A16 expression.

S100A16 mediation of weight gain attenuation induced by dietary calcium

Dietary calcium influences the regulation of energy metabolism, and weight gain is attenuated by a high-calcium diet. S100A16 is a novel calcium-binding signaling protein of the EF-hand superfamily that promotes adipogenesis. This study aimed to investigate the effect of S100A16 on weight gain attenuation with a calcium-rich diet. An obese rat model was produced after feeding with a high-fat diet. Animals were randomly divided into 4 groups according to the diet provided over 8 weeks: normal diet group; high-fat, normal-calcium diet group; high-fat, high-calcium diet (HH) group; and high-fat, low-calcium diet group. Serum biochemistry was analyzed, and body weight and visceral fat pads were measured. Expression of S100A16 was assayed by Western blotting. Adipogenesis was detected by oil red O staining. Increases in body weight and visceral fat weight were attenuated in the HH group. High-calcium diets decreased the concentrations of serum total cholesterol and triglyceride. Expression of S100A16 decreased in the HH group. Using the 3T3-L1 preadipocyte model, it was observed that elevation of intracellular Ca(2+) via calcium ionophores led to the exclusion of S100A16 from the nucleus. Overexpression of S100A16 in 3T3-L1 preadipocytes enhanced adipogenesis, although a significant reduction in Akt phosphorylation was also detected. High-calcium diets were associated with a significant reduction in body weight gain. High-calcium diets may lead to nuclear exclusion of S100A16, which results in the inhibition of adipogenesis and enhanced insulin sensitivity.

Identification of S100A16 as a novel adipogenesis promoting factor in 3T3-L1 cells

S100A16 is a member of S100 protein super family that carries calcium-binding EF-hand motifs. Its expression is ubiquitous and elevated in various types of tumors. The functions of S100 proteins are still being defined, although many members of S100 protein family are traditionally considered as markers of tumor tissues. Using 3T3-L1 preadipocyte model, we investigated the expression and function of S100A16 during differentiation into adipocytes as well as the potential roles of S100A16 in the regulation of insulin sensitivity. We found that the expression of S100A16 was increased during differentiation and that elevation of intracellular Ca(2+) via calcium ionophores led to its nucleus exclusion. Overexpression of S100A16 in 3T3-L1 preadipocytes increased their proliferation and markedly enhanced adipogenesis but resulted in significant reduction of insulin-stimulated glucose uptake and phosphorylation of AKT. In contrast, suppression of S100A16 expression with two different types of RNA interference significantly inhibited adipogenesis and preadipocyte proliferation. Immunoprecipitation analysis revealed that S100A16 could physically interact with tumor suppressor protein p53, also a known inhibitor of adipogenesis. Overexpression or RNA interference-initiated reduction of S100A16 led to the inhibition or activation of the expression of p53-responsive genes, respectively. Interestingly, Western blot assays showed that S100A16 protein levels were markedly higher in the adipose tissues of diet-induced obese mice and the ob/ob mice than that in control lean mice. Thus, we reveal for the first time that S100A16 protein is a novel adipogenesis-promoting factor and that increased expression of S100A16 in 3T3-L1 adipocytes can have a negative impact on insulin sensitivity.

Structural characterization of human S100A16, a low-affinity calcium binder

The homodimeric structure of human S100A16 in the apo state has been obtained both in the solid state and in solution, resulting in good agreement between the structures with the exception of two loop regions. The homodimeric solution structure of human S100A16 was also calculated in the calcium(II)-bound form. Differently from most S100 proteins, the conformational rearrangement upon calcium binding is minor. This characteristic is likely to be related to the weak binding affinity of the protein for the calcium(II) ions. In turn, this is ascribed to the lack of the glutamate residue at the end of the S100-specific N-domain binding site, which in most S100 proteins provides two important side chain oxygen atoms as calcium(II) ligands. Furthermore, the presence of hydrophobic interactions stronger than for other S100 proteins, present in the closed form of S100A16 between the third and fourth helices, likely make the closed structure of the second EF-hand particularly stable, so even upon calcium(II) binding such a conformation is not disrupted.

Transfection with liver-type glutaminase cDNA alters gene expression and reduces survival, migration and proliferation of T98G glioma cells

Liver-type glutaminase (LGA) is a glutaminase isoform that has been implicated in transcription modulation. LGA mRNA is absent from postoperative samples of primary gliomas and is low in cultured astrocytes. In this study, stable transfection of T98G cells with a vector carrying human LGA sequence increased the expression of LGA mRNA and protein, and the ability of the cells to degrade glutamine (Gln), as manifested by a three-fold reduction of their steady-state Gln content and a 2.5-fold increase of their glutamate (Glu) content. The transfected cells (TLGA cells) showed a 40% decrease of cell survival as assessed by colony formation, well correlated with significant reduction of mitochondrial activity as demonstrated with MTT test. Also, a 45% reduction of cell migration and a 47% decrease of proliferation index (Ki67 immunostaining) were found as compared with sham-transfected cells. Microarray analysis, which included over 47,000 transcripts, revealed a significantly altered expression of 85 genes in TLGA, but not in sham-transfected or control cells (P < 0.005). Microarray data were confirmed with real-time PCR analysis for eight genes potentially relevant to malignancy: S100A16, CAPN2, FNDC3B, DYNC1LI1, TIMP4, MGMT, ADM, and TIMP1. Of these changes, decreased expression of S100A16 and MGMT can be best reconciled with the current views on the role of their protein products in glioma malignancy. Malignancy-reducing effect of newly inserted LGA mRNA in glioblastoma cells can be reconciled with a hypothesis that absence of such a modulatory mechanism in glia-derived tumors deprived of LGA mRNA may facilitate some aspects of their progression.

Glutamine in neoplastic cells: focus on the expression and roles of glutaminases

Glutamine is an important source of energy for neoplastic tissues, and products of its metabolism include, among others, glutamate (Glu) and glutathione (GSH), the two molecules that play a key role in tumor proliferation, invasiveness and resistance to therapy. Glutamine hydrolysis in normal and transforming mammalian tissues alike, is carried out by different isoforms of glutaminases, of which the two major are liver-type glutaminase (LGA) and kidney-type glutaminase (KGA). This brief review summarizes available data on the expression profiles and activities of these isoenzymes in different neoplastic tissues as compared to the tissues of origin, and dwells on recent work demonstrating effects of manipulation of glutaminase expression on tumor growth. A comment is devoted to the emerging evidence that LGA, apart from degrading Gln for metabolic purposes, is involved in gene transcription; its enforced overexpression in glioma cells was found to reduce their proliferation and migration.

Physiological stress induces the metastasis marker AGR2 in breast cancer cells

As an approach to understanding the factors that activate expression of tumor progression genes, the role of physiological stress in the activation of a panel of tumor cell markers was investigated. These studies identify the developmental gene product, anterior gradient 2 (AGR2) as a cancer cell marker specifically up-regulated in response to depletion of serum and oxygen. AGR2 has been identified as a tumor marker in primary and secondary cancer lesions, and as a marker for detection of circulating tumor cells (CTCs). Elevated levels of AGR2 are known to increase the metastatic potential of cancer cells, but conditions leading to increased expression of AGR2 are not well understood. The present results identify novel physiological parameters likely to contribute to AGR2 induction in situ.

Pathologies involving the S100 proteins and RAGE

The S100 proteins are exclusively expressed in vertebrates and are the largest subgroup within the superfamily of EF-hand Ca2(+)-binding proteins Generally, S100 proteins are organized as tight homodimers (some as heterodimers). Each subunit is composed of a C-terminal, 'canonical' EF-hand, common to all EF-hand proteins, and a N-terminal, 'pseudo' EF-hand, characteristic of S100 proteins. Upon Ca2(+)-binding, the C-terminal EF-hand undergoes a large conformational change resulting in the exposure of a hydrophobic surface responsible for target binding A unique feature of this protein family is that some members are secreted from cells upon stimulation, exerting cytokine- and chemokine-like extracellular activities via the Receptor for Advanced Glycation Endproducts, RAGE. Recently, larger assemblies of some S100 proteins (hexamers, tetramers, octamers) have been also observed and are suggested to be the active extracellular species required for receptor binding and activation through receptor multimerization Most S100 genes are located in a gene cluster on human chromosome 1q21, a region frequently rearranged in human cancer The functional diversification of S100 proteins is achieved by their specific cell- and tissue-expression patterns, structural variations, different metal ion binding properties (Ca2+, Zn2+ and Cu2+) as well as their ability to form homo-, hetero- and oligomeric assemblies Here, we review the most recent developments focussing on the biological functions of the S100 proteins and we discuss the presently available S100-specific mouse models and their possible use as human disease models In addition, the S100-RAGE interaction and the activation of various cellular pathways will be discussed. Finally, the close association of S100 proteins with cardiomyopathy, cancer, inflammation and brain diseases is summarized as well as their use in diagnosis and their potential as drug targets to improve therapies in the future.