High Expression of S100A6 Predicts Unfavorable Prognosis of Lung Squamous Cell Cancer

S100A6 could not promote the differentiation of Calu-6 lung cancer cell line

Background

Our previous study demonstrated that S100 calcium binding protein A6 (S100A6) impairs tumorigenesis by Calu-6 lung cancer cells, as well as inhibit their growth. However, the role that S100A6 plays in tumor cell differentiation has not been previously explored. This study aimed to confirm the effect of S100A6 on the direction of differentiation in the human lung cancer cell linem Calu-6m based on our previous published research.

Materials and methods

A S100A6-overexpressing lentiviral vector was successfully constructed in our previous study. Nude mouse tumorigenicity was then applied successfully, and 15 mice were divided into three groups (Calu-6, Calu-6/neo, Calu-6/S100A6). After 5 weeks, we detected lung cancer markers with immunohistochemistry in mice tumor tissues, including the adenocarcinoma markers, TTF-1 and NapsinA, the squamous cell carcinoma markers, P40, CK5/6 and P63, and the small cell lung cancer markers CD56, Syn, CgA, TTF-1, CK, and Ki-67. Differences among the three groups were statistically compared.

Results

All the above-mentioned markers were positive in the tumor tissues of all three groups, and there were no significant differences.

Conclusion

S100A6 cannot promote differentiation of the undifferentiated human lung cancer cell line, Calu-6, into adenocarcinoma, squamous, or small cell carcinoma cell lines.

The role of miR-6884-5p in epithelial-mesenchymal transition in non-small cell lung cancer

Significant progress has been made in the management of non-small cell lung cancer (NSCLC), though a big barrier remains, which is epithelial-mesenchymal transition (EMT). Our study aimed to evaluate the function of miR-6884-5p and S100A16 in EMT-aggravated NSCLC. The tumor tissues and adjacent tissues from 92 NSCLC patients were collected to analyze the expression of miR-6884-5p and S100A16. Then lung cancer cell line A549 was co-transfected with miR-6884-5p mimics and S100A16 to further evaluate their function. Compared to adjacent tissues, low expression of miR-6884-5p was observed in the NSCLC tissues and associated with severe NSCLC progression. MiR-6884-5p expression was negatively correlated with EMT in NSCLC. Luciferase assay data revealed that miR-6884-5p could directly bind to the 3'UTR of S100A16 and inhibited the expression of S100A16 in A549 cells. Moreover, miR-6884-5p mimics significantly ameliorated EMT progression, and overexpression of S100A16 could reverse the inhibitory effect of miR-6884-5p in A549 cells. MiR-6884-5p inhibited EMT through directly targeting S100A16 in NSCLC. Our findings suggest that miR-6884-5p could be a diagnostic marker of NSCLC, as well as a potential candidate for NSCLC treatment.

S100A6: molecular function and biomarker role

S100A6 (also called calcyclin) is a Ca2+-binding protein that belongs to the S100 protein family. S100A6 has many functions related to the cytoskeleton, cell stress, proliferation, and differentiation. S100A6 also has many interacting proteins that are distributed in the cytoplasm, nucleus, cell membrane, and outside the cell. Almost all these proteins interact with S100A6 in a Ca2+-dependent manner, and some also have specific motifs responsible for binding to S100A6. The expression of S100A6 is regulated by several transcription factors (such as c-Myc, P53, NF-κB, USF, Nrf2, etc.). The expression level depends on the specific cell type and the transcription factors activated in specific physical and chemical environments, and is also related to histone acetylation, DNA methylation, and other epigenetic modifications. The differential expression of S100A6 in various diseases, and at different stages of those diseases, makes it a good biomarker for differential diagnosis and prognosis evaluation, as well as a potential therapeutic target. In this review, we mainly focus on the S100A6 ligand and its transcriptional regulation, molecular function (cytoskeleton, cell stress, cell differentiation), and role as a biomarker in human disease and stem cells.

S100A6 Protein-Expression and Function in Norm and Pathology

S100A6, also known as calcyclin, is a calcium-binding protein belonging to the S100 protein family. It was first identified and purified more than 30 years ago. Initial structural studies, focused mostly on the mode and affinity of Ca²⁺ binding and resolution of the resultant conformational changes, were soon complemented by research on its expression, localization and identification of binding partners. With time, the use of biophysical methods helped to resolve the structure and versatility of S100A6 complexes with some of its ligands. Meanwhile, it became clear that S100A6 expression was altered in various pathological states and correlated with the stage/progression of many diseases, including cancers, indicative of its important, and possibly causative, role in some of these diseases. This, in turn, prompted researchers to look for the mechanism of S100A6 action and to identify the intermediary signaling pathways and effectors. After all these years, our knowledge on various aspects of S100A6 biology is robust but still incomplete. The list of S100A6 ligands is growing all the time, as is our understanding of the physiological importance of these interactions. The present review summarizes available data concerning S100A6 expression/localization, interaction with intracellular and extracellular targets, involvement in Ca²⁺-dependent cellular processes and association with various pathologies.

Metal exposure from additive manufacturing and its effect on the nasal lavage fluid proteome - a pilot study

The use of metal additive manufacturing (AM) is steadily increasing and is an emerging concern regarding occupational exposure. In this study, non-invasive sampled nasal lavage fluid (NLF) from the upper airways was collected from metal AM operators at the beginning and end of a workweek during two consecutive years with preventive interventions in the occupational setting in-between (n = 5 year 1, n = 9 year 2). During year one, NLF was also collected from welders (n = 6) from the same company to get a comparison with a traditional manufacturing technique with known exposure and health risks. The samples were investigated using untargeted proteomics, as well as using multi-immunoassay to analyze a panel of 71 inflammatory protein markers. NLF in AM operators from year 1 showed decreased levels of Immunoglobulin J and WAP four-disulfide core domain protein 2 and increased levels of Golgi membrane protein 1, Uteroglobin and Protein S100-A6 at the end of the workweek. At year two, after preventive interventions, there were no significant differences at the end of the workweek. In welders, Annexin A1 and Protein S100-A6 were increased at the end of the workweek. The analysis of 71 inflammatory biomarkers showed no significant differences between the beginning and the end of workweek year 1 in AM operators. We identified several proteins of interest in the AM operators that could serve as possible markers for exposure in future studies with a larger cohort for validation.

The S100 Protein Family as Players and Therapeutic Targets in Pulmonary Diseases

The S100 protein family consists of over 20 members in humans that are involved in many intracellular and extracellular processes, including proliferation, differentiation, apoptosis, Ca₂⁺ homeostasis, energy metabolism, inflammation, tissue repair, and migration/invasion. Although there are structural similarities between each member, they are not functionally interchangeable. The S100 proteins function both as intracellular Ca²⁺ sensors and as extracellular factors. Dysregulated responses of multiple members of the S100 family are observed in several diseases, including the lungs (asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, pulmonary hypertension, and lung cancer). To this degree, extensive research was undertaken to identify their roles in pulmonary disease pathogenesis and the identification of inhibitors for several S100 family members that have progressed to clinical trials in patients for nonpulmonary conditions. This review outlines the potential role of each S100 protein in pulmonary diseases, details the possible mechanisms observed in diseases, and outlines potential therapeutic strategies for treatment.

The S100 protein family in lung cancer

The S100 protein family is involved in the pathogenesis of several malignancies including lung cancer. Recent studies have shown that one member, S100A2, was over-expressed in advanced stage non-small cell lung cancer (NSCLC). Another, S100A6, demonstrated variable expression in different lung cancer subtypes. Research using NSCLC cell lines reported that SIX3 inhibited cell metastasis and proliferation via S100P down-regulation. This review represents an update on S100 proteins in lung cancer from 2017 to 2021 and includes the aforementioned as well as S100A4, S100A7, and S100B. Inconsistencies in mechanisms of action for S100A8/S100A9 are highlighted and a comprehensive evaluation of the most recent evidence for the S100 proteins in lung cancer is presented.

S100A6 represses Calu-6 lung cancer cells growth via inhibiting cell proliferation, migration, invasion and enhancing apoptosis

S100 calcium binding protein A6 (S100A6) has been reported to involve in many kinds of cancers through regulating intracellular calcium homeostasis. Previous studies found that S100A6 increased in lung cancer patients' plasma and pleural effusion. This study focused on its function in Calu-6 lung cancer cells. S100A6 gene was transferred into Calu-6 lung cancer cell line by lentivirus vector, the empty vector transfected cells and the blank cells were set as control groups. MTT was evaluating cell proliferation. The transwell assay was reflecting cell migration and cell invasion. The flow cytometric analysis was detecting cell apoptosis and cell cycle of three groups (Calu-6, Calu-6/neo, Calu-6/S100A6). Nude mouse tumorigenicity was then applied to evaluate S100A6's effect on cellular tumorigenicity. Compared with control groups, Calu-6/S100A6 cells showed a weakening trend in the cell behaviours of proliferation, migration and invasiveness, while had an enhancement of cell apoptosis, with all P < .05. The cell cycle of Calu-6/S100A6 cells had a reduction of S phase and an increase of G1 phase (P < .05). In animal study, after 5 weeks of cell injection, the tumour bulk of Calu-6/S100A6 group was smaller than controls, with P < .05. Our results demonstrate S100A6 inhibits the growth of Calu-6 lung cancer cells, as well as impairs Calu-6's ability in tumorigenesis. At cellular level, S100A6 is supposed to act as a tumour suppressor gene in lung cancer.

S100 family members: potential therapeutic target in patients with hepatocellular carcinoma: A STROBE study

Proteins in S100 family exhibit different expressions patterns and perform different cytological functions, playing substantial roles in certain cancers, carcinogenesis, and disease progression. However, the expression and role of S100 family members in the prognosis of hepatocellular carcinoma (HCC) remains unclear. To investigate the effect of S100 family members for the prognosis of liver cancer, we assessed overall survival (OS) using a Kaplan-Meier plotter (KM plotter) in liver cancer patients with different situation. Our results showed that 15 members of the S100 family exhibited high levels of expression and these levels were correlated with OS in liver cancer patients. The higher expression of S100A5, S100A7, S100A7A, S100A12, S100Z, and S100G was reflected with better survival in liver cancer patients. However, worse prognosis was related to higher levels of expression of S100A2, S100A6, S100A8, S100A9, S100A10, S100A11, S10013, S100A14, and S100P. We then evaluated the prognostic values of S100 family members expression for evaluating different stages of AJCC-T, vascular invasion, alcohol consumption, and the presence of hepatitis virus in liver cancer patients. Lastly, we studied the prognostic values of S100 family members expression for patients after sorafenib treatment. In conclusion, our findings show that the proteins of S100 family members exhibit differential expression and may be useful as targets for liver cancer, facilitating novel diagnostic and therapeutic strategies in cancer.

Prognostic values of S100 family mRNA expression in ovarian cancer

S100 family is made up of at least 20 calcium-binding proteins which are involved in many cellular processes. The prognostic values of individual S100 member in ovarian cancer patients are still unknown. In this study, we performed a detailed prognostic values of S100 in ovarian cancer. The mRNA expression levels of S100 family in various cancers were analyzed via the Oncomine, and the protein-protein interaction network of S100 family was analyzed via String. The prognostic values of individual S100 member were evaluated via Kaplan-Meier Plotter. The S100 family genes expression and mutation were analyzed via cBioProtal. We observed that the mRNA expression of most S100 family were overexpressed in ovarian cancer compared with normal tissues. In survival analysis in Kaplan-Meier Plotter, 10 members of S100 family showed significant correlation with overall survival in ovarian cancer patients. The trends of high expression of individual S100 members were nearly the same in different subtype and pathological grades. However, the S100 family genes expression and mutation showed no significant prognostic values in overall survival and disease free survival in ovarian cancer patients. Although, the results need more verification both in clinical trials and fundamental experiments, our study provide new insights for the prognostic function of S100 family in ovarian cancer and might promote development of S100 targeted inhibitors for the new treatment of ovarian cancer.

S100A6/miR193a regulates the proliferation, invasion, migration and angiogenesis of lung cancer cells through the P53 acetylation

Non-small cell lung cancer (NSCLC) is accounted for 80% to 85% of the total lung cancer cases and still a difficult problem to solve at present. The present study was aimed to explore the effect of S100A6 on the proliferation, invasion, migration and angiogenesis in lung cancer cell lines with the change of miR-193a expression and P53 acetylation. The expression of S100A6, CDK2, cyclinD1, VEGF, ANGII, anti-acetylp53 (K373), K-AC, P21 and Noxa were analyzed by western blot analysis. RT-qPCR analysis was used to confirm the transfection effects. CCK-8 assay and flow cytometry were reflecting the cell proliferation. Wound healing assay and transwell assay were evaluating the cell invasion and migration. The dual-luciferase reporter assay was to confirm the S100A6 as a target of miR-193a. Immunofluorescence and immunohistochemical analysis were analyzing the S100A6 expression in cells and tumor tissues, respectively. As a result, S100A6 expression was increased in lung cancer cell lines and S100A6 expressed the highest in A549 cells which was chosen for the subsequent experiment. S100A6 overexpression promoted the proliferation, invasion, migration and angiogenesis of lung cancer cells with the promotion of degradation of P53 acetylation. In addition, S100A6 was demonstrated to be a target of miR193a. Moreover, miR193a expression was decreased in lung cancer cell lines and miR193a expressed the lowest in A549 cells which was chosen for the subsequent experiment. And, miR193a overexpression inhibited the proliferation, invasion, migration and angiogenesis of lung cancer cells with the enhancement of P53 acetylation. The effects of S100A6 overexpression and miR193a overexpression on tumor growth in vivo experiments were the same with that in the cell experiments. In conclusion, this study indicated that S100A6 overexpression could promote the proliferation, invasion, migration and angiogenesis of lung cancer cells by inhibiting the P53 acetylation and miR193a overexpression could reversed the above effects by decreasing the S100A6 expression in both vitro and vivo experiments.

Identification of differentially expressed genes in pancreatic ductal adenocarcinoma and normal pancreatic tissues based on microarray datasets

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignant tumor with rapid progression and poor prognosis. In the present study, 11 high‑quality microarray datasets, comprising 334 tumor samples and 151 non‑tumor samples from the Gene Expression Omnibus, were screened, and integrative meta‑analysis of expression data was used to identify gene signatures that differentiate between PDAC and normal pancreatic tissues. Following the identification of differentially expressed genes (DEGs), two‑way hierarchical clustering analysis was performed for all DEGs using the gplots package in R software. Hub genes were then determined through protein‑protein interaction network analysis using NetworkAnalyst. In addition, functional annotation and pathway enrichment analyses of all DEGs were conducted in the Database for Annotation, Visualization, and Integrated Discovery. The expression levels and Kaplan‑Meier analysis of the top 10 upregulated and downregulated genes were verified in The Cancer Genome Atlas. A total of 1,587 DEGs, including 1,004 upregulated and 583 downregulated genes, were obtained by comparing PDAC with normal tissues. Of these, hematological and neurological expressed 1, integrin subunit α2 (ITGA2) and S100 calcium‑binding protein A6 (S100A6) were the top upregulated genes, and kinesin family member 1A, Dymeclin and β‑secretase 1 were the top downregulated genes. Reverse transcription‑quantitative PCR was performed to examine the expression levels of S100A6, KRT19 and GNG7, and the results suggested that S100A6 was significantly upregulated in PDAC compared with normal pancreatic tissues. ITGA2 overexpression was significantly associated with shorter overall survival times, whereas family with sequence similarity 46 member C overexpression was strongly associated with longer overall survival times. In addition, network‑based meta‑analysis confirmed growth factor receptor‑bound protein 2 and histone deacetylase 5 as pivotal hub genes in PDAC compared with normal tissue. In conclusion, the results of the present meta‑analysis identified PDAC‑related gene signatures, providing new perspectives and potential targets for PDAC diagnosis and treatment.

S100A6 activates EGFR and its downstream signaling in HaCaT keratinocytes

Epidermal growth factor receptor (EGFR) is a central transmitter of mitogenic signals in epithelial cells; enhanced EGFR activity is observed in many tumors of epithelial origin. S100A6 is a small calcium-binding protein, characteristic mainly of epithelial cells and fibroblasts, strongly implicated in cell proliferation and upregulated in tumors. In this study, using biochemical assays along with immunohistochemical and immunocytochemical analysis of organotypic and standard cultures of HaCaT keratinocytes with S100A6 overexpression or knock-down, we have examined the effect of S100A6 on EGFR activity and downstream signaling. We found that HaCaT cells overexpressing S100A6 had enhanced EGFR, phospho EGFR, and phospho extracellular signal-regulated kinase 1/2 (pERK1/2) staining intensity and level coupled to higher signal transducer and activator of transcription 3 (STAT3) activity. Conversely, S100A6 knockdown cells had impaired EGFR signaling that could be enhanced by addition of recombinant S100A6 to the culture media. Altogether the results show that S100A6 may exert its proproliferative effects through activating EGFR.

Expression and Comparison of Cbl-b in Lung Squamous Cell Carcinoma and Adenocarcinoma

Background

Non-small cell lung carcinoma (NSCLC) mainly includes lung squamous cell carcinoma and adenocarcinoma. This study aimed to investigate the difference between the expression of Cbl-b in lung squamous cell carcinoma and adenocarcinoma.

Material/Methods

The clinical features and survival data of NSCLC patients and Cbl-b mRNA (FPKM) were obtained from the TCGA database. Then, lung squamous cell carcinoma and adenocarcinoma cell lines were transfected with lentivirus-mediated RNA interference vector to knockdown the expression of Cbl-b. Next, a Transwell assay was performed to study the effect of Cbl-b shRNA on migration and invasion of lung squamous cell carcinoma and adenocarcinoma cells. Finally, Western blot analysis was performed to measure the expressions of PI3K, p-PI3K, AKT, p-AKT, ERK1/2, p-ERK1/2, GSK3β, p-GSK3β, mTOR, and p-mTOR protein in lung adenocarcinoma and squamous cell carcinoma cells.

Results

The correlation of Cbl-b expression and OS was different between NSCLC adenocarcinoma and squamous carcinoma. After transfection, the expression of Cbl-b was inhibited in A549, H1975, and SW900 cells. Cbl-b shRNA promoted the migration and invasion of lung adenocarcinoma A549 and H1975 cells, but it inhibited the invasion of lung squamous cell carcinoma SW900 cells. In addition, Cbl-b regulated the expression of PI3K and ERK1/2-GSK3β pathway proteins in A549 and SW900 cells.

Conclusions

The OS of Cbl-b mRNA low expression in lung adenocarcinoma and squamous cell carcinoma was different. The difference in signal pathways may be one of the reasons for the difference in the correlation between Cbl-b expression and the survival rate of these 2 pathological types of lung cancer.