Down-regulation of S100A2 in lymph node metastases of head and neck cancer

High expression of S100A2 predicts poor prognosis in patients with endometrial carcinoma

Background

S100A2, a member of the S100 protein family, is abnormally expressed and plays a vital role in multiple cancers. However, little is known about the clinical significance of S100A2 in endometrial carcinoma.

Methods

Clinicopathological data were obtained from The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Gene Expression Omnibus (GEO), and Clinical Proteomic Tumor Analysis Consortium (CPTAC). First, the expression and prognostic value of different S100 family members in endometrial carcinoma were evaluated. Subsequently, the Kaplan–Meier plotter and Cox regression analysis were used to assess the prognostic significance of S100A2, while the association between S100A2 expression and clinical characteristics in endometrial carcinoma was also analyzed using logistic regression. A receiver operating characteristic (ROC) curve and a nomogram were constructed. The putative underlying cellular mechanisms were explored using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and gene set enrichment analysis (GSEA).

Results

Our results revealed that S100A2 expression was significantly higher in endometrial carcinoma tissue than in non-cancerous tissue at both the mRNA and protein levels. Analysis of Kaplan–Meier plotter data revealed that patients with high S100A2 expression had shorter overall survival (OS) and disease specific survival (DSS) compared with those of patients with low S100A2 expression. Multivariate Cox analysis further confirmed that high S100A2 expression was an independent risk factor for OS in patients with endometrial carcinoma. Other clinicopathologic features found to be related to worse prognosis in endometrial carcinoma included age, clinical stage, histologic grade, and tumor invasion. Importantly, ROC analysis also confirmed that S100A2 has a high diagnostic value in endometrial carcinoma. KEGG enrichment analysis and GSEA revealed that the estrogen and IL-17 signaling pathways were significantly upregulated in the high S100A2 expression group, in which estrogen response, JAK-STAT3, K-Ras, and TNFα/NF-κB were differentially enriched.

Conclusions

S100A2 plays an important role in endometrial carcinoma progression and may represent an independent diagnostic and prognostic biomarker for endometrial carcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09180-5.

Evaluation of SHP1-P2 methylation as a biomarker of lymph node metastasis in patients with squamous cell carcinoma of the head and neck

Background

Hypermethylation of Src homology region 2 domain-containing protein-tyrosine phosphatase 1 promoter 2 (SHP1-P2) has been proven as an epithelial-specific marker. This marker has been used for the detection of lymph node metastasis in patients with lung cancer or colon cancer.

Objectives

To investigate SHP1-P2 methylation in patients with squamous cell carcinoma of the head and neck (HNSCC) and determine its potential for micrometastasis detection in the lymph nodes of patients with HNSCC.

Methods

SHP1-P2 methylation levels were analyzed by combined methylation-specific primer TaqMan real-time PCR in 5 sample groups: normal tonsils (n = 10), microdissected squamous cell carcinoma epithelia (n = 9), nonmetastatic head and neck cancer lymph nodes (LN N0, n = 15), metastatic HNSCC histologically negative for tumor cells (LN–, n = 18), and matched cases histologically positive for tumor cells (LN+, n = 18).

Results

SHP1-P2 methylation of 10.27 ± 4.05% was found in normal tonsils as a lymphoid tissue baseline, whereas it was 61.31 ± 17.00% in microdissected cancer cell controls. In the 3 lymph node groups, the SHP1-P2 methylation levels were 9.99 ± 6.61% for LN N0, 14.49 ± 10.03% for LN- Nx, and 41.01 ± 24.51% for LN+ Nx. The methylation levels for LN- Nx and LN+ Nx were significantly different (P = 0.0002). Receiver operating characteristic curve analysis of SHP1-P2 methylation demonstrated an area under the curve of 0.637 in distinguishing LN N0 from LN– Nx.

Conclusions

SHP1-P2 methylation was high in HNSCC, and low in lymphoid tissues. This methylation difference is concordant with lymph node metastasis.

Tyr99 phosphorylation determines the regulatory milieu of tumor suppressor p73

p73 is a member of the p53 tumor suppressor family, which mediates genotoxic stress response by triggering cell cycle arrest and apoptosis. Similar to p53, p73 is maintained at very low levels, but it gets rapidly induced upon genotoxic stress. Mounting evidences demonstrate that p73 is primarily regulated posttranslationally. However, the molecular mechanisms which determine its stability and activity discerningly under normal and stress conditions are still not well understood. Here, we employed a proteomics approach to identify differential interactors of p73 under normal and genotoxic stress conditions. We report here that TRIM28, an E3 ligase, interacts with p73 and targets it for proteasomal degradation under normal conditions. Genotoxic stress-induced phosphorylation of p73 at tyrosine 99 residue by c-abl kinase leads to abrogation of this interaction thereby promoting p73 stabilization. Furthermore, the phosphorylated form of p73 specifically interacts with MED15, which serves as a transcriptional coactivator and leads to activation of proarrest, proapoptotic and anti-metastatic genes. RNAi-mediated abrogation of TRIM28 expression facilitates p73-mediated tumor suppression in mouse tumor models, whereas disruption of MED15 expression abrogates p73 tumor suppressor and anti-metastatic functions. These findings provide new insights into the pivotal role of Tyr99 phosphorylation in determining p73 levels and functions.

Epigenetic silencing of S100A2 in bladder and head and neck cancers

S100A2, a member of the S100 protein family, is known to be downregulated in a number of human cancers, leading to its designation as a potential tumor suppressor gene. Here, we investigated the expression and methylation status of S100A2 in head&neck and bladder cancer. Reduced mRNA and protein expression was observed in 8 head&neck and bladder cancer cell lines. To explore the mechanism responsible for the downregulation of S100A2, we treated six cell lines with 5-aza-2'-deoxycytidine. We found S100A2 is silenced in association with aberrant promoter-region methylation and its expression is restored with 5-aza-2'-deoxycytidine treatment. Of 31 primary head&neck cancer cases and 31 bladder cancer cases, promoter methylation was detected in 90% and 80% of cases, respectively. Interestingly, only 1/9 of normal head&neck tissues and 2/6 of normal bladder tissues showed promoter methylation. S100A2 promoter methylation can be detected in urine and is more frequent in bladder cancer patients than in healthy subjects (96% vs 48% respectively). Moreover, increased methylation of S100A2 is linked to the progression of the tumor in bladder cancer (p<0.01). Together, this data shows that methylation-associated inactivation of S100A2 is frequent and may be an important event in the tumorigenesis of head&neck and bladder cancer.

Clinical significance of S100A2 expression in gastric cancer

Gastric carcinoma (GC) is one of the most common malignancies worldwide. To identify the candidate carcinoma-related biomarker in GC, comparative proteome technique was performed in resected GC tissues and matched adjacent non-cancerous gastric tissues (ANGT). As a result, S100A2 was successfully identified to be down-regulated significantly in GC compared with ANGT. Western blot analysis validated decreased expression of S100A2, and its expression level was related with the degree of tumor differentiation and status of lymph node metastasis in GC. Furthermore, immunohistochemistry analysis showed S100A2 down-expression was significantly associated with poor differentiation (P < 0.05), advanced depth of invasion (P < 0.05) and lymph node metastasis (P < 0.05) in GC. Kaplan-Meier curves showed that the relapse-free probability and the overall survival rate were significantly decreased with S100A2 expression decreasing (P < 0.05). Cox regression analysis indicated S100A2 down-expression was a negative independent prognostic biomarker for GC. A supplement of S100A2 protein by S100A2 expression vector significantly decreased the number of invaded cancer cells MGC-803. However, knockdown of S100A2 expression by siRNA interference compromised the invasion ability of MGC-803 cells. Moreover, S100A2 negatively regulated MEK/ERK signaling pathway, and activation of this signaling pathway by S100A2 down-regulation increased in vitro invasion of MGC-803 cells. In conclusion, this study demonstrated the clinical significance of S100A2 expression in GC, and loss of S100A2 expression contributes to GC development and progression. Therefore, the determination of S100A2 expression levels contributes to predict the outcome of GC patients.

Label-free selected reaction monitoring enables multiplexed quantitation of S100 protein isoforms in cancer cells

In humans, the S100 protein family is composed of 21 highly related low molecular weight (∼10 kDa) proteins. These proteins are known to have diagnostic, prognostic, and predictive value in a variety of cancers, but their small size and high sequence homology present a challenging scenario for quantitative bioanalytical procedures. Here, we developed a multiplexed, label-free selected reaction monitoring (SRM) assay to specifically measure the S100 protein isoform family in cancer cells. Several normalization parameters associated with label-free SRM quantitation were investigated to derive a method with optimal precision. We detected 11 S100 isoforms across a panel of 9 colon and breast cancer cell lines. The quantitative potential of the S100 assays for biomarker discovery was demonstrated by studying the isogenic cell lines SW480 and SW620, a cellular model of colon cancer progression. Our findings were shown to be in agreement with previously published polysomal mRNA level quantitation for S100 genes in these cell lines. Comparison of the quantitation results using label-free SRM with those obtained using stable-isotope labeled peptide standards demonstrated reliability of the method. These data support the use of SRM to quantitate S100 protein isoforms as these are important players in a broad range of human diseases.

Clinical significance of altered S100A2 expression in gastric cancer

The S100A2 gene has been reported to be a putative tumor‑suppressor gene. Nevertheless, overexpression of S100A2 has been found in certain types of cancer. This study investigated S100A2 expression in tissue specimens of gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer to determine its association with clinical features. A serial of tissue samples (gastritis, intestinal metaplasia, adenomatous dysplasia and gastric cancer samples) were used for quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), western blotting and immunohistochemical analyses of S100A2 expression. The data revealed that there was a gradual loss of S100A2 expression from gastritis, intestinal metaplasia and dysplasia to cancer tissue specimens (p<0.001). In gastric cancer samples, loss of S100A2 expression was associated with increased tumor size, depth of invasion, lymph node metastasis and a poor prognosis (p<0.001). However, the intestinal type of gastric cancer expressed more S100A2 protein than the diffuse type (p<0.001). In conclusion, data from the present study demonstrated that loss of S100A2 expression contributes to gastric cancer development and progression; therefore, the determination of S100A2 expression levels may help to predict the carcinogenesis and aggressiveness of gastric cancer as well as patient survival.

Identification of novel tumor suppressor genes down-regulated in recurrent nasopharyngeal cancer by DNA microarray

The nasopharyngeal cancer is a common cancer among southern Chinese. In order to better understand molecular mechanism of recurrent nasopharyngeal cancer (rNPC), we used DNA microarray to identify down-regulated tumor suppressed genes (TSGs) in rNPC, and bioinformatics to analyze their chromosomal localizations and molecular functions. Eight non-recurrent nasopharyngeal cancer (nNPC) and six rNPC tissue samples were selected, and Affymetrix Gene1.0 ST chips were used to construct the expression profiling of each tissue sample. Identify the down-regulated TSGs in rNPC by comparing expression profiling data of two type tissue samples. A total of five TSGs were identified to be down-regulated in rNPC. These five TSGs include SERPINF1, TPD52L1, FBLN1, RASSF6, and S100A2, and Signal Log Ratio were -2.2, -2.3, -3.5, -3.9 and -6.9 respectively. Chromosomal localization analysis showed that S100A2, RASSF6, TPD52L1, SERPINF1, and FBLN1 were located on chromosomes 1q, 4q, 6q, 17p and 22q, respectively. Functional analysis showed that SERPINF1 and TPD52L1 belonged to enzyme activity genes, S100A2 and FBLN1 belonged to calcium ion binding genes, RASSF6 belong to protein binding genes. Five TSGs likely to be the candidate TSGs involved in rNPC, and may play important roles in occurrence of rNPC. Chromosomes 1q, 4q, 6q, 17p and 22q may be considered as important region for screening TSGs that may relevant to rNPC. Those genes and chromosomal region need to be further studied.

S100A2 promoter-driven conditionally replicative adenovirus targets non-small-cell lung carcinoma

S100A2, a member of the S100 family of calcium-binding proteins, has been implicated in carcinogenesis as both a tumor suppressor and stimulator. Here, we characterized promoter activity of S100A2, generated an S100A2 promoter-driven conditionally replicative adenovirus (Ad/SA), and evaluated its anti-tumor activity in vitro and in vivo. Promoter activity of S100A2 was greatly restricted to tumor cells, and the S100A2 promoter bound with typical nuclear targets of epidermal growth factor receptor (EGFR) signaling. EGF-stimulated EGFR phosphorylation induced S100A2 expression and further activated E1A expression of Ad/SA, which was restored by EGFR signal inhibition in a concentration-dependent manner in non-small-cell lung carcinoma (NSCLC). In two EGFR-activated tumor xenograft animal models, Ad/SA exhibited potent anti-tumor activity, whereas cetuximab, an EGFR-targeting anticancer drug, was active transiently or ineffective. Combined treatment with cetuximab or cisplatin plus Ad/SA resulted in enhanced anti-tumor activity. Immunohistochemical analysis of tumor sections showed moderate-to-high grade signals for EGFR and adenovirus, and a reduction in viable cells in Ad/SA-treated tumors. Collectively, these results demonstrate that the S100A2 promoter-driven adenovirus is a potent inhibitor of cancers, and further suggest that S100A2 is a target gene of EGFR signaling pathway in NSCLC.

Epigenetic regulation of S100 protein expression

S100 proteins are small, calcium-binding proteins whose genes are localized in a cluster on human chromosome 1. Through their ability to interact with various protein partners in a calcium-dependent manner, the S100 proteins exert their influence on many vital cellular processes such as cell cycle, cytoskeleton activity and cell motility, differentiation, etc. The characteristic feature of S100 proteins is their cell-specific expression, which is frequently up- or downregulated in various pathological states, including cancer. Changes in S100 protein expression are usually characteristic for a given type of cancer and are therefore often considered as markers of a malignant state. Recent results indicate that changes in S100 protein expression may depend on the extent of DNA methylation in the S100 gene regulatory regions. The range of epigenetic changes occurring within the S100 gene cluster has not been defined. This article reviews published data on the involvement of epigenetic factors in the control of S100 protein expression in development and cancer.

Loss of Reprimo and S100A2 expression in human gastric adenocarcinoma

Reprimo and S100A2 are two newly identified candidate tumor-suppressor genes, which play an important role in the regulation of p53-dependent cell cycle. In this study, we examined the expressions of Reprimo and S100A2 in surgical specimens of gastric adenocarcinoma and correlated these results with pathological and clinical parameters. Tissues were obtained from 100 gastric adenocarcinoma patients that underwent curative gastrectomy. Reprimo and S100A2 expressions were evaluated by immunohistochemical analysis. Loss of Reprimo and S100A2 expressions occurred in 65 and 52% of the patients, respectively. Loss of Reprimo expression was significantly correlated with the depth of tumor invasion (P = 0.000), lymphatic vessel invasion (P = 0.006), and lymph node metastasis (P = 0.000). Loss of S100A2 expression was significantly associated with histological type (P = 0.009), depth of invasion (P = 0.033), lymphatic vessel invasion (P = 0.01), and lymph node metastasis (P = 0.001). In addition, there was a significant positive association between the expressions of Reprimo and S100A2 (P < 0.01). The results suggest that loss of Reprimo and S100A2 expressions occurs frequently in gastric adenocarcinomas. The expressions of Reprimo and S100A2 may be potential biomarkers for gastric adenocarcinomas detection.

S100A2 in cancerogenesis: a friend or a foe?

Owing to the exceptional intracellular distribution and the heterogeneous expression pattern during transformation and metastasis in various tumors, the EF-hand calcium-binding protein S100A2 attracts increasing attention. Unlike the majority of S100 proteins, S100A2 expression is downregulated in many cancers and the loss in nuclear expression has been associated with poor prognosis. On the other hand, S100A2 is upregulated in some cancers. This mini review highlights the general characteristics of S100A2 and discusses recent findings on its putative functional implication as a suppressor or promoter in cancerogenesis.

Restoration of caveolin-1 expression suppresses growth and metastasis of head and neck squamous cell carcinoma

Caveolin-1 (Cav-1) plays an important role in modulating cellular signalling, but its role in metastasis is not well defined. A significant reduction in Cav-1 levels was detected in lymph node metastases as compared with primary tumour of head and neck squamous cell carcinoma (HNSCC) specimens (P<0.0001), confirming the downregulation of Cav-1 observed in a highly metastatic M4 cell lines derived from our orthotopic xenograft model. To investigate the function of Cav-1 in metastasis of HNSCC, we compared stable clones of M4 cells carrying human cav-1 cDNA (CavS) with cells expressing an empty vector (EV) in vitro and in the orthotopic xenograft model. Overexpression of Cav-1 suppressed growth of the CavS tumours compared with the EV tumours. The incidence of lung metastases was significantly lower in animals carrying CavS tumours than those with EV tumours (P=0.03). In vitro, CavS cells displayed reduced cell growth, invasion, and increased anoikis compared with EV cells. In CavS cells, Cav-1 formed complex with integrin beta1 and Src. Further application of integrin beta1 neutralising antibody or Src inhibitor PP2 to EV cells illustrated similar phenotypes as CavS cells, suggesting that Cav-1 may play an inhibitory role in tumorigenesis and lung metastasis through regulating integrin beta1- and Src-mediated cell-cell and cell-matrix interactions.

Transcriptional activation of the tumor suppressor and differentiation gene S100A2 by a novel p63-binding site

S100A2 is generally found expressed in the epidermis and was recently shown to play a crucial role in the differentiation of keratinocytes. Also known as CaN19, S100A2 was identified as a potential tumor suppressor. Expression of S100A2 is upregulated by p53. The proteins p63 and p73 are related to p53 and are expressed as several splice variants with partially overlapping tasks but also functions different from p53. It had been shown that p63 proteins with mutations in their DNA-binding domain cause severe phenotypes in man as autosomal dominantly inherited disease including EEC, AEC, SHFM, LMS and ADULT syndromes. Here we show that S100A2 is a transcriptional target of p63/p73 family members, particularly the p63 splice variant TAp63γ. The regulation is mediated by a novel transcriptional element in the S100A2 promoter which is bound by TAp63γ but not by p53. Mutant p63 proteins derived from EEC and ADULT syndrome patients cannot activate S100A2 transcription whereas SHFM-related mutants still can stimulate the S100A2 promoter. Consistent with a function in tumor suppression S100A2 expression is stimulated upon DNA damage. After doxorubicin treatment p63γ proteins are recruited to the S100A2 promoter in vivo. This may indicate a function of the p63-dependent S100A2 regulation in tumor suppression.