S100A4 interacts with p53 in the nucleus and promotes p53 degradation

ANXA9 facilitates S100A4 and promotes breast cancer progression through modulating STAT3 pathway

Breast cancer has the highest global incidence and mortality rates among all cancer types. Abnormal expression of the Annexin family has been observed in different malignant tumors, including upregulated ANXA9 in breast cancer. We found highly expressed ANXA9 in metastatic breast cancer tissues, which is correlated with breast cancer progression. In vitro, the functional experiments indicated ANXA9 influenced breast cancer proliferation, motility, invasion, and apoptosis; in vivo, downregulation of ANXA9 suppressed breast cancer xenograft tumor growth and lung metastasis. Mechanically, on one side, we found that ANXA9 could mediate S100A4 and therefore regulate AKT/mTOR/STAT3 pathway to participate p53/Bcl-2 apoptosis; on the other side, we found ANXA9 transferred S100A4 from cells into the tumor microenvironment and mediated the excretion of cytokines IL-6, IL-8, CCL2, and CCL5 to participate angiogenesis via self- phosphorylation at site Ser2 and site Thr69. Our findings demonstrate significant involvement of ANXA9 in promoting breast cancer progression, thereby suggesting that therapeutic intervention via targeting ANXA9 may be effective in treating metastatic breast cancer.

Targeted Destruction of S100A4 Inhibits Metastasis of Triple Negative Breast Cancer Cells

Most patients who die of cancer do so from its metastasis to other organs. The calcium-binding protein S100A4 can induce cell migration/invasion and metastasis in experimental animals and is overexpressed in most human metastatic cancers. Here, we report that a novel inhibitor of S100A4 can specifically block its increase in cell migration in rat (IC50, 46 µM) and human (56 µM) triple negative breast cancer (TNBC) cells without affecting Western-blotted levels of S100A4. The moderately-weak S100A4-inhibitory compound, US-10113 has been chemically attached to thalidomide to stimulate the proteasomal machinery of a cell. This proteolysis targeting chimera (PROTAC) RGC specifically eliminates S100A4 in the rat (IC50, 8 nM) and human TNBC (IC50, 3.2 nM) cell lines with a near 20,000-fold increase in efficiency over US-10113 at inhibiting cell migration (IC50, 1.6 nM and 3.5 nM, respectively). Knockdown of S100A4 in human TNBC cells abolishes this effect. When PROTAC RGC is injected with mouse TNBC cells into syngeneic Balb/c mice, the incidence of experimental lung metastases or local primary tumour invasion and spontaneous lung metastasis is reduced in the 10-100 nM concentration range (Fisher's Exact test, p ≤ 0.024). In conclusion, we have established proof of principle that destructive targeting of S100A4 provides the first realistic chemotherapeutic approach to selectively inhibiting metastasis.

Pharmacological Inhibition of S100A4 Attenuates Fibroblast Activation and Renal Fibrosis

The TGF-β/Smad3 signaling pathway is an important process in the pathogenesis of kidney fibrosis. However, the molecular mechanisms are not completely elucidated. The current study examined the functional role of S100A4 in regulating TGF-β/Smad3 signaling in fibroblast activation and kidney fibrosis development. S100A4 was upregulated in the kidney in a murine model of renal fibrosis induced by folic acid nephropathy. Further, S100A4 was predominant in the tubulointerstitial cells of the kidney. Pharmacological inhibition of S100A4 with niclosamide significantly attenuated fibroblast activation, decreased collagen content, and reduced extracellular matrix protein expression in folic acid nephropathy. Overexpression of S100A4 in cultured renal fibroblasts significantly facilitated TGF-β1-induced activation of fibroblasts by increasing the expression of α-SMA, collagen-1 and fibronectin. In contrast, S100A4 knockdown prevented TGF-β1-induced activation of fibroblast and transcriptional activity of Smad3. Mechanistically, S100A4 interacts with Smad3 to stabilize the Smad3/Smad4 complex and promotes their translocation to the nucleus. In conclusion, S100A4 facilitates TGF-β signaling via interaction with Smad3 and promotes kidney fibrosis development. Manipulating S100A4 may provide a beneficial therapeutic strategy for chronic kidney disease.

In silico Prediction of Deleterious Single Nucleotide Polymorphism in S100A4 Metastatic Gene: Potential Early Diagnostic Marker

S100A4 protein overexpression has been reported in different types of cancer and plays a key role by interacting with the tumor suppressor protein Tp53. Single nucleotide polymorphisms (SNP) in S100A4 could directly influence the biomolecular interaction with the tumor suppressor protein Tp53 due to their aberrant conformations. Hence, the study was designed to predict the deleterious SNP and its effect on the S100A4 protein structure and function. Twenty-one SNP data sets were screened for nonsynonymous mutations and subsequently subjected to deleterious mutation prediction using different computational tools. The screened deleterious mutations were analyzed for their changes in functionality and their interaction with the tumor suppressor protein Tp53 by protein-protein docking analysis. The structural effects were studied using the 3DMissense mutation tool to estimate the solvation energy and torsion angle of the screened mutations on the predicted structures. In our study, 21 deleterious nonsynonymous mutations were screened, including F72V, E74G, L5P, D25E, N65S, A28V, A8D, S20L, L58P, and K26N were found to be remarkably conserved by exhibiting the interaction either with the EF-hand 1 or EF-hand 2 domain. The solvation and torsion values significantly deviated for the mutant-type structures with S20L, N65S, and F72L mutations and showed a marked reduction in their binding affinity with the Tp53 protein. Hence, these deleterious mutations might serve as prospective targets for diagnosing and developing personalized treatments for cancer and other related diseases.

S100A11 activates the pentose phosphate pathway to induce malignant biological behaviour of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most refractory malignancies and has a poor prognosis. In recent years, increasing evidence has shown that an imbalance of metabolism may contribute to unrestricted pancreatic tumour progression and that the pentose phosphate pathway (PPP) plays a pivotal role in cellular metabolism. S100A11 has been shown to regulate multiple biological functions related to the progression and metastasis of various cancer types. However, the exact mechanisms and prognostic value of S100A11 in PDAC remain unclear. Here, we found that S100A11 expression was increased in PDAC and significantly associated with worse prognosis and disease progression. Mechanistically, S100A11 knockdown suppressed the PPP by impairing nascent mRNA synthesis of TKT (transketolase). The current study also demonstrated that H3K4me3 at the -268/+77 region of the TKT promoter was required for its transcriptional activation and S100A11 promoted H3K4me3 loading to the TKT promoter by interacting with SMYD3 protein. Taking these findings together, this study provided new insights into the potential value of S100A11 for treating pancreatic cancer, suggesting that it could be a therapeutic target for PDAC patients.

Repurposing of ingenol mebutate for treating human colorectal cancer by targeting S100 calcium-binding protein A4 (S100A4)

Colorectal cancer (CRC) is the world's second most common cause of cancer-related death. Novel treatments are still urgently needed. S100 calcium-binding protein A4 (S100A4) was demonstrated to be an anticancer therapeutic target. Herein, we found that higher S100A4 expression was associated with a poorer prognosis in publicly available cohorts and a Taiwanese CRC patient cohort. To identify repurposed S100A4 inhibitors, we mined the Connectivity Map (CMap) database for clinical drugs mimicking the S100A4-knockdown gene signature. Ingenol mebutate, derived from the sap of the plant Euphorbia peplus, is approved as a topical treatment for actinic keratosis. The CMap analysis predicted ingenol mebutate as a potent S100A4 inhibitor. Indeed, both messenger RNA and protein levels of S100A4 were attenuated by ingenol mebutate in human CRC cells. In addition, CRC cells with higher S100A4 expressions and/or the wild-type p53 gene were more sensitive to ingenol mebutate, and their migration and invasion were inhibited by ingenol mebutate. Therefore, our results suggest the repurposing of ingenol mebutate for treating CRC by targeting S100A4.

Functional interaction between S100A1 and MDM2 may modulate p53 signaling in normal and malignant endometrial cells

BACKGROUND

S100A1 expression is deregulated in a variety of human malignancies, but its role in normal and malignant endometrial cells is unclear.

METHODS

We used endometrial carcinoma (Em Ca) cell lines to evaluate the physical and functional interaction of S100A1 with p53 and its negative regulator, mouse double minute 2 (MDM2). We also evaluated the expression of S100A1, p53, and MDM2 in clinical samples consisting of 89 normal endometrial and 189 Em Ca tissues.

RESULTS

S100A1 interacted with MDM2 but not p53 in Em Ca cell lines. Treatment of cells stably overexpressing S100A1 with Nutlin-3A, an inhibitor of the p53/MDM2 interaction, increased expression of p53-target genes including p21^waf1 and BAX. S100A1 overexpression enhanced cellular migration, but also sensitized cells to the antiproliferative and proapoptotic effects of Adriamycin, a genotoxic agent; these phenotypes were abrogated when S100A1 was knocked down using shRNA. In clinical samples from normal endometrium, S100A1 expression was significantly higher in endometrial glandular cells of the middle/late secretory and menstrual stages when compared to cells in the proliferative phases; high S100A1 was also positively correlated with expression of MDM2 and p21^waf1 and apoptotic status, and inversely correlated with Ki-67 scores. However, such correlations were absent in Em Ca tissues.

CONCLUSION

The interaction between S100A1 and MDM2 may modulate proliferation, susceptibility to apoptosis, and migration through alterations in p53 signaling in normal- but not malignant-endometrial cells.

Single-cell analysis of human glioma and immune cells identifies S100A4 as an immunotherapy target

A major rate-limiting step in developing more effective immunotherapies for GBM is our inadequate understanding of the cellular complexity and the molecular heterogeneity of immune infiltrates in gliomas. Here, we report an integrated analysis of 201,986 human glioma, immune, and other stromal cells at the single cell level. In doing so, we discover extensive spatial and molecular heterogeneity in immune infiltrates. We identify molecular signatures for nine distinct myeloid cell subtypes, of which five are independent prognostic indicators of glioma patient survival. Furthermore, we identify S100A4 as a regulator of immune suppressive T and myeloid cells in GBM and demonstrate that deleting S100a4 in non-cancer cells is sufficient to reprogram the immune landscape and significantly improve survival. This study provides insights into spatial, molecular, and functional heterogeneity of glioma and glioma-associated immune cells and demonstrates the utility of this dataset for discovering therapeutic targets for this poorly immunogenic cancer.

The Role of ATRA, Natural Ligand of Retinoic Acid Receptors, on EMT-Related Proteins in Breast Cancer: Minireview

The knowledge of the structure, function, and abundance of specific proteins related to the EMT process is essential for developing effective diagnostic approaches to cancer with the perspective of diagnosis and therapy of malignancies. The success of all-trans retinoic acid (ATRA) differentiation therapy in acute promyelocytic leukemia has stimulated studies in the treatment of other tumors with ATRA. This review will discuss the impact of ATRA use, emphasizing epithelial-mesenchymal transition (EMT) proteins in breast cancer, of which metastasis and recurrence are major causes of death.

Studying the Structures of Relaxed and Fuzzy Interactions: The Diverse World of S100 Complexes

S100 proteins are small, dimeric, Ca²⁺-binding proteins of considerable interest due to their associations with cancer and rheumatic and neurodegenerative diseases. They control the functions of numerous proteins by forming protein–protein complexes with them. Several of these complexes were found to display “fuzzy” properties. Examining these highly flexible interactions, however, is a difficult task, especially from a structural biology point of view. Here, we summarize the available in vitro techniques that can be deployed to obtain structural information about these dynamic complexes. We also review the current state of knowledge about the structures of S100 complexes, focusing on their often-asymmetric nature.

p53 Transactivation Domain Mediates Binding and Phase Separation with Poly-PR/GR

The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the presence of poly-PR/GR dipeptide repeats, which are encoded by the chromosome 9 open reading frame 72 (C9orf72) gene. Recently, it was shown that poly-PR/GR alters chromatin accessibility, which results in the stabilization and enhancement of transcriptional activity of the tumor suppressor p53 in several neurodegenerative disease models. A reduction in p53 protein levels protects against poly-PR and partially against poly-GR neurotoxicity in cells. Moreover, in model organisms, a reduction of p53 protein levels protects against neurotoxicity of poly-PR. Here, we aimed to study the detailed molecular mechanisms of how p53 contributes to poly-PR/GR-mediated neurodegeneration. Using a combination of biophysical techniques such as nuclear magnetic resonance (NMR) spectroscopy, fluorescence polarization, turbidity assays, and differential interference contrast (DIC) microscopy, we found that p53 physically interacts with poly-PR/GR and triggers liquid–liquid phase separation of p53. We identified the p53 transactivation domain 2 (TAD2) as the main binding site for PR25/GR25 and showed that binding of poly-PR/GR to p53 is mediated by a network of electrostatic and/or hydrophobic interactions. Our findings might help to understand the mechanistic role of p53 in poly-PR/GR-associated neurodegeneration.

S100A4 promotes the progression of lipopolysaccharide-induced acute epididymitis in mice†

S100A4 has been suggested to be a critical regulator of tumor metastasis and is implicated in the progression of inflammation. The aim of this study is to investigate the expression and possible role of S100A4 in epididymitis. Using a mouse model of epididymitis induced by the injection of lipopolysaccharide (LPS) in the deferent duct, we found that LPS administration induced an upregulation of S100a4 transcription (P < 0.05) and a recruitment of S100A4 positive cells in the epididymal interstitium of wild type (WT) mice. Co-immunofluorescence showed that S100A4 was mainly expressed by granulocytes, CD4 lymphocytes, and macrophages. Deficiency of S100A4 reduced epididymal pathological reaction and the mRNA levels of the pro-inflammatory cytokines IL-1β and TNF-α (P < 0.01), suggesting that S100A4 promotes the progression of epididymitis. Furthermore, S100A4 deficiency alleviated the decline of sperm motility and rectified the abnormal expression of sperm membrane protein AMAD3, which suggested that in the progression of epididymitis, S100A4 aggravates the damage to sperm vitality. In addition, both Ki-67 marked cell proliferation and transferase-mediated dUTP-biotin nick end labeling detected cell apoptosis were reduced in S100a4-/- mice compared with WT mice after LPS treatment, indicating that S100A4 promotes both cell proliferation and cell apoptosis in epididymitis. Overall, these results demonstrate that S100A4 promotes the progression of LPS-induced epididymitis and facilitates a decline in sperm vitality, and its function may be related to the process of cell proliferation and apoptosis during inflammation.

Systematic screening identifies a TEAD4-S100A13 axis modulating cisplatin sensitivity of oral squamous cell carcinoma cells

BACKGROUND

This study aimed to screen prognosis-related S100 protein family members in human paxpillomaviruses (HPV)-negative oral squamous cell carcinoma (OSCC) and their molecular regulations.

METHODS

Bioinformatic screening was conducted based on single-cell RNA-seq data from Puram 2017 dataset and bulk-seq data from the Cancer Genome Atlas (TCGA). HPV-negative OSCC cell lines CAL-27 and SCC-4 were used as in vitro cell models.

RESULTS

Among 21 S100 protein family member genes, S100A13 upregulation was associated with unfavorable progression-free survival and disease-specific survival of OSCC patients. Gene Set Enrichment Analysis showed that the higher S100A13 expression group had elevated genes enriched in DNA repair and oxidative phosphorylation. S100A13 knockdown increased cisplatin sensitivity, while its overexpression decreased the sensitivity of CAL-27 and SCC-4 cells. S100A13 gene had complex alternative transcription patterns. ENST00000440685 is one of the major protein-coding transcripts and was the only transcript elevated in the tumor group. TEAD4 could bind to the promoter of ENST00000440685 and increase its transcription. TEAD4 overexpression alleviated the tumor-suppressive effect of cisplatin in terms of colony formation, the expression of apoptotic proteins, and DNA damage. However, S100A13 knockdown partly abrogated the protective effects of TEAD4 overexpression.

CONCLUSION

This study revealed a novel TEAD4-S100A13 axis that might modulate cisplatin sensitivity of OSCC tumor cells.

S100A4 Is Involved in Stimulatory Effects Elicited by the FGF2/FGFR1 Signaling Pathway in Triple-Negative Breast Cancer (TNBC) Cells

Triple-negative breast cancer (TNBC) is an aggressive breast tumor subtype characterized by poor clinical outcome. In recent years, numerous advancements have been made to better understand the biological landscape of TNBC, though appropriate targets still remain to be determined. In the present study, we have determined that the expression levels of FGF2 and S100A4 are higher in TNBC with respect to non-TNBC patients when analyzing “The Invasive Breast Cancer Cohort of The Cancer Genome Atlas” (TCGA) dataset. In addition, we have found that the gene expression of FGF2 is positively correlated with S100A4 in TNBC samples. Performing quantitative PCR, Western blot, CRISPR/Cas9 genome editing, promoter studies, immunofluorescence analysis, subcellular fractionation studies, and ChIP assays, we have also demonstrated that FGF2 induces in TNBC cells the upregulation and secretion of S100A4 via FGFR1, along with the ERK1/2–AKT–c-Rel transduction signaling. Using conditioned medium from TNBC cells stimulated with FGF2, we have also ascertained that the paracrine activation of the S100A4/RAGE pathway triggers angiogenic effects in vascular endothelial cells (HUVECs) and promotes the migration of cancer-associated fibroblasts (CAFs). Collectively, our data provide novel insights into the action of the FGF2/FGFR1 axis through S100A4 toward stimulatory effects elicited in TNBC cells.

S100A4 in the Physiology and Pathology of the Central and Peripheral Nervous System

S100A4 is a member of the large family of S100 proteins, exerting a broad range of intracellular and extracellular functions that vary upon different cellular contexts. While S100A4 has long been implicated mainly in tumorigenesis and metastatization, mounting evidence shows that S100A4 is a key player in promoting pro-inflammatory phenotypes and organ pro-fibrotic pathways in the liver, kidney, lung, heart, tendons, and synovial tissues. Regarding the nervous system, there is still limited information concerning S100A4 presence and function. It was observed that S100A4 exerts physiological roles contributing to neurogenesis, cellular motility and chemotaxis, cell differentiation, and cell-to cell communication. Furthermore, S100A4 is likely to participate to numerous pathological processes of the nervous system by affecting the functions of astrocytes, microglia, infiltrating cells and neurons and thereby modulating inflammation and immune reactions, fibrosis as well as neuronal plasticity and survival. This review summarizes the current state of knowledge concerning the localization, deregulation, and possible functions of S100A4 in the physiology of the central and peripheral nervous system. Furthermore, we highlight S100A4 as a gene involved in the pathogenesis of neurological disorders such as brain tumors, neurodegenerative diseases, and acute injuries.

Tumor-Suppressor p53TAD1-60 Forms a Fuzzy Complex with Metastasis-Associated S100A4: Structural Insights and Dynamics by an NMR/MD Approach

Conformationally flexible protein complexes represent a major challenge for structural and dynamical studies. We present herein a method based on a hybrid NMR/MD approach to characterize the complex formed between the disordered p53TAD1-60 and the metastasis-associated S100A4. Disorder-to-order transitions of both TAD1 and TAD2 subdomains upon interaction is detected. Still, p53TAD1-60 remains highly flexible in the bound form, with residues L26, M40, and W53 being anchored to identical hydrophobic pockets of the S100A4 monomer chains. In the resulting "fuzzy" complex, the clamp-like binding of p53TAD1-60 relies on specific hydrophobic anchors and on the existence of extended flexible segments. Our results demonstrate that structural and dynamical NMR parameters (cumulative Δδ, SSP, temperature coefficients, relaxation time, hetNOE) combined with MD simulations can be used to build a structural model even if, due to high flexibility, the classical solution structure calculation is not possible.

S100A4/Nonmuscle Myosin IIA/p53 Axis Contributes to Aggressive Features in Ovarian High-Grade Serous Carcinoma

S100A4 is a small calcium-binding protein that exerts its biological functions by interacting with nonmuscle myosin IIA (NMIIA) and p53. Although S100A4 promotes metastasis in several tumors, little is known about its involvement in the progression of ovarian high-grade serous carcinomas (HGSCs). Herein, we focused on functional roles of the S100A4/NMIIA/p53 axis in these tumors. In HGSC cell lines harboring mutant p53, knockdown (KD) of S100A4 reduced the expression of several epithelial-mesenchymal transition/cancer stem cell markers and the ALDH1^high population, consistent with an inhibition of stemness features. S100A4-KD also increased apoptosis, decreased cell proliferation, and accelerated cell mobility. This was accompanied by increased Snail expression, which, in turn, was likely due to loss of p53 function. In contrast, specific inhibition of NMIIA by blebbistatin induced phenotypes that-with the exception of cell proliferation and mobility-were opposite to those observed in S100A4-KD cells. In clinical samples, cytoplasmic and/or nuclear interactions between S100A4, NMIIA, and mutant p53 were observed. In addition, high expression of S100A4, but not NMIIA or p53, was a significant and independent unfavorable prognostic factor in HGSC patients. These findings suggest that, via its interaction with NMIIA and p53, overexpressed S100A4 may induce epithelial-mesenchymal transition/cancer stem cell properties in HGSC and elicit several other tumor-associated phenotypes.

Structure Determination of the Transactivation Domain of p53 in Complex with S100A4 Using Annexin A2 as a Crystallization Chaperone

To fully understand the environmental factors that influence crystallization is an enormous task, therefore crystallographers are still forced to work "blindly" trying as many crystallizing conditions and mutations to improve crystal packing as possible. Numerous times these random attempts simply fail even when using state-of-the-art techniques. As an alternative, crystallization chaperones, having good crystal-forming properties, can be invoked. Today, the almost exclusively used such protein is the maltose-binding protein (MBP) and crystallographers need other widely applicable options. Here, we introduce annexin A2 (ANXA2), which has just as good, if not better, crystal-forming ability than the wild-type MBP. Using ANXA2 as heterologous fusion partner, we were able to solve the atomic resolution structure of a challenging crystallization target, the transactivation domain (TAD) of p53 in complex with the metastasis-associated protein S100A4. p53 TAD forms an asymmetric fuzzy complex with the symmetric S1004 and could interfere with its function.

Pentamidine inhibit S100A4 - p53 interaction and decreases cell proliferation activity

Metastasis-associated S100A4 protein is a small calcium-binding protein typically overexpressed in several tumor forms, and it is widely accepted that S100A4 plays a significant role in the metastasis of cancer. Tumor suppressor p53 is one of the S100A4's main targets. Previous reports show that through p53, S100A4 regulates collagen expression and cell proliferation. When S100A4 interacts with p53, the S100A4 destabilizes wild type p53. In the current study, based on ¹H-¹⁵N HSQC NMR experiments and HADDOCK results, S100A4 interacts with the intrinsically unstructured transactivation domain (TAD) of the protein p53 and the pentamidine molecules in the presence of calcium ions. Our results suggest that the p53 TAD and pentamidine molecules share similar binding sites on the S100A4 protein. This observation indicates that a competitive binding mechanism can interfere with the binding of S100A4-p53 and increase the level of p53. Also, we compare different aspects of p53 activity in the WST-1 test using MCF 7 cells. We found that the presence of a pentamidine molecule results in higher p53 activity, which is also reflected in less cell proliferation. Collectively, our results indicate that disrupting the S100A4-p53 interaction would prevent cancer progression, and thus S100A4-p53 inhibitors provide a new avenue for cancer therapy.

Proteomics pinpoints alterations in grade I meningiomas of male versus female patients

Meningiomas are among the most common primary tumors of the central nervous system (CNS) and originate from the arachnoid or meningothelial cells of the meninges. Surgery is the first option of treatment, but depending on the location and invasion patterns, complete removal of the tumor is not always feasible. Reports indicate many differences in meningiomas from male versus female patients; for example, incidence is higher in females, whereas males usually develop the malignant and more aggressive type. With this as motivation, we used shotgun proteomics to compare the proteomic profile of grade I meningioma biopsies of male and female patients. Our results listed several differentially abundant proteins between the two groups; some examples are S100-A4 and proteins involved in RNA splicing events. For males, we identified enriched pathways for cell-matrix organization and for females, pathways related to RNA transporting and processing. We believe our findings contribute to the understanding of the molecular differences between grade I meningiomas of female and male patients.

Effect of shRNA-mediated regulation of S100A4 gene expression on proliferation and apoptosis of KLE endometrial cancer cells

PURPOSE

To investigate the effect of shRNA-regulated S100A4 expression on the proliferation and apoptosis in KLE endometrial cancer cells.

METHODS

S100A4-OVER and S100A4-shRNA were transfected into KLE endometrial cancer cells using lentiviral sh-RNA technology. Passive OVER-NC cell line and shRNA-NC cell line were used as a negative control group and non-transfected Control cell line as a blank control group. After 48 h of transfection, the expressions of S100A4 and protein were detected by real-time fluorescence quantitative PCR and Western blotting, respectively. CCK-8 detection and flow cytometer were used to detect cell proliferation and apoptosis, respectively.

RESULTS

Compared with the normal control group and the negative control group, the transfection efficiency and shRNA targeting of the shRNA-interfered S100A4 gene were verified at the levels of mRNA and protein expression. The expression of the disrupted S100A4 gene at S100A4 mRNA and protein levels in endometrial cancer cells was determined. The proliferation efficiency of KLE cells in S100A4-OVER group was significantly higher than that in other four groups; the proliferation rate of S100A4-shRNA cells decreased slightly;, the apoptotic rate of KLE cells in S100A4-shRNA group increased significantly, and the apoptotic rate of KLE cells in S100A4-OVER group decreased compared with NC group.

CONCLUSION

Specific regulation of S100A4 gene expression:, the enhanced expression of the S100A4 gene may promote the proliferation of KLE endometrial cancer cells; the inhibited expression of the S100A4 gene may promote the apoptosis of KLE endometrial cancer cells. S100A4 expression is closely related to the biological characteristics of endometrial cancer.

Up-regulation of S100A4 expression by HBx protein promotes proliferation of hepatocellular carcinoma cells and its correlation with clinical survival

BACKGROUND

Hepatocellular carcinoma is one of the most common cancers worldwide. HBV-related HCC has characteristics of faster progression and worse prognosis. Previous studies have confirmed that HBx protein plays numbers of important roles in development of HBV-HCC. However, the molecular mechanism of carcinogenicity of HBx is still not well documented.

METHODS

Firstly, a HCC cell line over-expressing HBx was established and its function was verified. Subsequently, the differentially expressed genes were detected by transcriptome sequencing technology and use the Western Blot technology to detect the up-regulated genes in HBx overexpressed cells, and the functional correlation of the genes was analyzed. Finally, tissue microarray was used to correlate up-regulated gene with clinical follow-up data to verify correlation with clinical prognosis.

RESULTS

Over-expression of HBx could promote cell proliferation, and over-expression of HBx could up-regulate the expression of S100A4 protein. ShRNA experiments showed that HBx promoted cell proliferation by upregulating the expression of S100A4. IFN-α2b can down-regulate the expression of S100A4 and inhibit the proliferation of HCC cells. The expression of S100A4 in cancer was significantly up-regulated compared with adjacent tissues, and was also significantly associated with tumors volume, the expression of PD-L1 and the survival time of patients with HCC.

CONCLUSION

In general, S100A4 may be an effective therapeutic target for HBV-HCC. And the connection between S100A4 and HBV are not clear yet. This study may play a guiding role in the future clinical treatment of HCC.

Immunohistochemical analysis of Bcl-2, nuclear S100A4, MITF and Ki67 for risk stratification of early-stage melanoma - A combined IHC score for melanoma risk stratification

BACKGROUND AND OBJECTIVES

Overall survival (OS) in patients with early-stage malignant melanoma differs. To date, there are no established prognostic markers. We aimed to contribute to a better understanding of potential prognostic immunohistochemical markers for risk stratification.

PATIENTS AND METHODS

161 surgically resected early-stage malignant melanomas (stage pT1 and pT2) were analyzed for expression of 20 different proteins using immunohistochemistry. The results were correlated with OS. The cohort was randomly split into a discovery and a validation cohort.

RESULTS

High Bcl-2 expression, high nuclear S100A4 expression as well as a Ki67 proliferation index of ≥ 20 % were associated with shorter OS. Strong MITF immunoreactivity was a predictor for favorable prognosis. A combination of these four markers resulted in a multi-marker score with significant prognostic value in multivariate survival analysis (HR: 3.704; 95 % CI 1.484 to 9.246; p = 0.005). Furthermore, the score was able to differentiate a low-risk group with excellent OS rates (five-year survival rate: 100 %), an intermediate-risk group (five-year survival rate: 81.8 %) and a high-risk group (five-year survival rate: 52.6 %). The prognostic value was confirmed within the validation cohort.

CONCLUSIONS

Combined immunohistochemical analysis of Bcl-2, nuclear S100A4, Ki67 and MITF could contribute to better risk stratification of early-stage malignant melanoma patients.

Biclustering-based association rule mining approach for predicting cancer-associated protein interactions

Protein-protein interactions (PPIs) have been widely used to understand different biological processes and cellular functions associated with several diseases like cancer. Although some cancer-related protein interaction databases are available, lack of experimental data and conflicting PPI data among different available databases have slowed down the cancer research. Therefore, in this study, the authors have focused on various proteins that are directly related to different types of cancer disease. They have prepared a PPI database between cancer-associated proteins with the rest of the human proteins. They have also incorporated the annotation type and direction of each interaction. Subsequently, a biclustering-based association rule mining algorithm is applied to predict new interactions with type and direction. This study shows the prediction power of association rule mining algorithm over the traditional classifier model without choosing a negative data set. The time complexity of the biclustering-based association rule mining is also analysed and compared to traditional association rule mining. The authors are able to discover 38 new PPIs which are not present in the cancer database. The biological relevance of these newly predicted interactions is analysed by published literature. Recognition of such interactions may accelerate a way of developing new drugs to prevent different cancer-related diseases.

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.

Overexpressed methyltransferase-like 1 (METTL1) increased chemosensitivity of colon cancer cells to cisplatin by regulating miR-149-3p/S100A4/p53 axis

Methyltransferase-like 1 (METTL1) mediated 7-methylguanosine (m7G) is crucial for the regulation of chemoresistance in cancer treatment. However, the role of METTL1 in regulating chemoresistance of colon cancer (CC) cells to cisplatin is still unclear. This study established the cisplatin-resistant CC (CR-CC) cells and found that METTL1 was low-expressed in CR-CC cells compared to their paired cisplatin-sensitive CC (CS-CC) cells. Besides, overexpressed METTL1 enhanced the cytotoxic effects of cisplatin on CR-CC cells. In addition, miR-149-3p was the downstream target of METTL1, which could be positively regulated by METTL1. Further results validated that miR-149-3p was low-expressed in CR-CC cells comparing to the CS-CC cells. In addition, the promoting effects of overexpressed METTL1 on cisplatin induced CR-CC cell death were abrogated by synergistically knocking down miR-149-3p. Furthermore, S100A4/p53 axis was the downstream target of METTL1 and miR-149-3p, and either overexpressed METTL1 or miR-149-3p increased p53 protein levels in CR-CC cells, which were reversed by upregulating S100A4. Similarly, the promoting effects of overexpressed METTL1 on cisplatin-induced CR-CC cell death were abrogated by overexpressing S100A4. Taken together, overexpression of METTL1 sensitized CR-CC cells to cisplatin by modulating miR-149-3p/S100A4/p53 axis.

MTGO-SC, A Tool to Explore Gene Modules in Single-Cell RNA Sequencing Data

The identification of functional modules in gene interaction networks is a key step in understanding biological processes. Network interpretation is essential for unveiling biological mechanisms, candidate biomarkers, or potential targets for drug discovery/repositioning. Plenty of biological module identification algorithms are available, although none is explicitly designed to perform the task on single-cell RNA sequencing (scRNA-seq) data. Here, we introduce MTGO-SC, an adaptation for scRNA-seq of our biological network module detection algorithm MTGO. MTGO-SC isolates gene functional modules by leveraging on both the network topological structure and the annotations characterizing the nodes (genes). These annotations are provided by an external source, such as databases and literature repositories (e.g., the Gene Ontology, Reactome). Thanks to the depth of single-cell data, it is possible to define one network for each cell cluster (typically, cell type or state) composing each sample, as opposed to traditional bulk RNA-seq, where the emerging gene network is averaged over the whole sample. MTGO-SC provides two complexity levels for interpretation: the gene-gene interaction and the intermodule interaction networks. MTGO-SC is versatile in letting the users define the rules to extract the gene network and integrated with the Seurat scRNA-seq analysis pipeline. MTGO-SC is available at https://github.com/ne1s0n/MTGOsc.

Mts1 Up-regulation is Associated With Aggressive Pathological Features in Thyroid Cancer

BACKGROUND/AIM

Thyroid cancer is the most common type of endocrine cancer and its incidence and mortality are increasing. However, few studies on the molecular factors related to its poor prognosis have been performed. The aim of our study was to identify a poor prognostic factor for thyroid cancer to reduce its overtreatment, recurrence, and mortality.

MATERIALS AND METHODS

The present study is a retrospective study of 55 patients who were diagnosed with papillary thyroid cancer and operated in Korea from September 2013 to November 2015.

RESULTS

Mts1 is a member of the S100 protein family and is involved in tumor progression and metastasis. Mts1 was highly expressed in patients with thyroid cancer and high Mts1 levels were related to poor prognoses such as lymph node metastasis.

CONCLUSION

Mts1 is associated with aggressive pathological features in thyroid cancer, and may be a poor prognostic factor for thyroid cancer.

The Multifaceted S100A4 Protein in Cancer and Inflammation

The metastasis-promoting S100A4 protein, a member of the S100 family, has recently been discovered as a potent factor implicated in various inflammation-associated diseases. S100A4 is involved in a range of biological functions such as angiogenesis, cell differentiation, apoptosis, motility, and invasion. Moreover, S100A4 is also a potent trigger of inflammatory processes and induces the release of cytokines and growth factors under different pathological conditions.Indeed, the release of S100A4 upon stress and mainly its pro-inflammatory role emerges as the most decisive activity in disease development, such as rheumatoid arthritis (RA), systemic sclerosis (SSc) allergy, psoriasis, and cancer. In the scope of this review, we will focus on the role of S100A4 as a mediator of pro-inflammatory pathways and its associated biological processes involved in the pathogenesis of various human noncommunicable diseases (NCDs) including cancer.

Expression profile and functional role of S100A14 in human cancer

S100A14 is one of the new members of the multi-functional S100 protein family. Expression of S100A14 is highly heterogeneous among normal human tissues, suggesting that the regulation of S100A14 expression and its function may be tissue- and context-specific. Compared to the normal counterparts, S100A14 mRNA and protein levels have been found to be deregulated in several cancer types, indicating a functional link between S100A14 and malignancies. Accordingly, S100A14 is functionally linked with a number of key signaling molecules such as p53, p21, MMP1, MMP9, MMP13, RAGE, NF-kB, JunB, actin and HER2. Of interest, S100A14 seems to have seemingly opposite functions in malignancies arising from the gastrointestional tract (tissues rich in epithelial components) compared to cancers in the other parts of the body (tissues rich in mesenchymal components). The underlying mechanism for these observations are currently unclear and may be related to the relative abundance and differences in the type of interaction partners (effector protein) in different cancer types and tissues. In addition, several studies indicate that the expression pattern of S100A14 has a potential to be clinically useful as prognostic biomarker in several cancer types. This review attempts to provide a comprehensive summary on the expression pattern and functional roles/related molecular pathways in different cancer types. Additionally, the prognostic potential of S100A14 in the management of human malignancies will be discussed.

S100A4 alters metabolism and promotes invasion of lung cancer cells by up-regulating mitochondrial complex I protein NDUFS2

It is generally accepted that alterations in metabolism are critical for the metastatic process; however, the mechanisms by which these metabolic changes are controlled by the major drivers of the metastatic process remain elusive. Here, we found that S100 calcium-binding protein A4 (S100A4), a major metastasis-promoting protein, confers metabolic plasticity to drive tumor invasion and metastasis of non-small cell lung cancer cells. Investigating how S100A4 regulates metabolism, we found that S100A4 depletion decreases oxygen consumption rates, mitochondrial activity, and ATP production and also shifts cell metabolism to higher glycolytic activity. We further identified that the 49-kDa mitochondrial complex I subunit NADH dehydrogenase (ubiquinone) Fe-S protein 2 (NDUFS2) is regulated in an S100A4-dependent manner and that S100A4 and NDUFS2 exhibit co-occurrence at significant levels in various cancer types as determined by database-driven analysis of genomes in clinical samples using cBioPortal for Cancer Genomics. Importantly, we noted that S100A4 or NDUFS2 silencing inhibits mitochondrial complex I activity, reduces cellular ATP level, decreases invasive capacity in three-dimensional growth, and dramatically decreases metastasis rates as well as tumor growth in vivo Finally, we provide evidence that cells depleted in S100A4 or NDUFS2 shift their metabolism toward glycolysis by up-regulating hexokinase expression and that suppressing S100A4 signaling sensitizes lung cancer cells to glycolysis inhibition. Our findings uncover a novel S100A4 function and highlight its importance in controlling NDUFS2 expression to regulate the plasticity of mitochondrial metabolism and thereby promote the invasive and metastatic capacity in lung cancer.

Circulating S100 proteins effectively discriminate SLE patients from healthy controls: a cross-sectional study

S100 proteins are currently being investigated as potential diagnostic and prognostic biomarkers of several cancers and inflammatory diseases. The aims of this study were to analyse the plasma levels of S100A4, S100A8/9 and S100A12 in patients with incomplete systemic lupus erythematosus (iSLE), in patients with established SLE and in healthy controls (HCs) and to investigate the potential utility of the S100 proteins as diagnostic or activity-specific biomarkers in SLE. Plasma levels were measured by ELISA in a cross-sectional cohort study of 44 patients with SLE, 8 patients with iSLE and 43 HCs. Disease activity was assessed using the SLEDAI-2K. The mean levels of all S100 proteins were significantly higher in SLE patients compared to HCs. In iSLE patients, the levels of S100A4 and S100A12 but not S100A8/9 were also significantly higher compared to HCs. There were no significant differences in S100 levels between the iSLE and SLE patients. Plasma S100 proteins levels effectively discriminated between SLE patients and HCs. The area under the curve (AUC) for S100A4, S100A8/9 and S100A12 plasma levels was 0.989 (95% CI 0.976-1.000), 0.678 (95% CI 0.563-0.792) and 0.807 (95% CI 0.715-0.899), respectively. S100 levels did not differentiate between patients with high and low disease activity. Only the S100A12 levels were significantly associated with SLEDAI-2K and with cSLEDAI-2K. S100 proteins were significantly higher in SLE patients compared HCs and particularly S100A4 could be proposed as a potential diagnostic biomarker for SLE.

S100A4 Gene is Crucial for Methionine-Choline-Deficient Diet-Induced Non-Alcoholic Fatty Liver Disease in Mice

PURPOSE

To explore the influence of S100 calcium binding protein A4 (S100A4) knockout (KO) on methionine-choline-deficient (MCD) diet-induced non-alcoholic fatty liver disease (NAFLD) in mice.

MATERIALS AND METHODS

S100A4 KO mice (n=20) and their wild-type (WT) counterparts (n=20) were randomly divided into KO/MCD, Ko/methionine-choline-sufficient (MCS), WT/MCD, and WT/MCS groups. After 8 weeks of feeding, blood lipid and liver function-related indexes were measured. HE, Oil Red O, and Masson stainings were used to observe the changes of liver histopathology. Additionally, expressions of S100A4 and proinflammatory and profibrogenic cytokines were detected by qRT-PCR and Western blot, while hepatocyte apoptosis was revealed by TUNEL staining.

RESULTS

Serum levels of aminotransferase, aspartate aminotransferase, triglyceride, and total cholesterol in mice were increased after 8-week MCD feeding, and hepatocytes performed varying balloon-like changes with increased inflammatory cell infiltration and collagen fibers; however, these effects were improved in mice of KO/MCD group. Meanwhile, total NAFLD activity scores and fibrosis were lower compared to WT+MCD group. Compared to WT/MCS group, S100A4 expression in liver tissue of WT/MCD group was enhanced. The expression of proinflammatory (TNF-α, IL-1β, IL-6) and profibrogenic cytokines (TGF-β1, COL1A1, α-SMA) in MCD-induced NAFLD mice were increased, as well as apoptotic index (AI). For MCD group, the expressions of proinflammatory and profibrogenic cytokines and AI in KO mice were lower than those of WT mice.

CONCLUSION

S100A4 was detected to be upregulated in NAFLD, while S100A4 KO alleviated liver fibrosis and inflammation, in addition to inhibiting hepatocyte apoptosis.

Protective effect and mechanism of rat recombinant S100 calcium-binding protein A4 on oxidative stress injury of rat vascular endothelial cells

The aim of the present study was to examine the protective effects and mechanisms of S100 calcium-binding protein A4 (S100A4) on endothelial cell apoptosis induced by oxidative stress injury. Endothelial cells were cultured and divided into control and oxidative stress injury groups, with the latter state induced by H₂O₂. Endothelial cells in every group were incubated with or without 50 or 100 µM S100A4. The cell viability and amounts of malondialdehyde, nitric oxide and lactate dehydrogenase in the culture medium were measured. The apoptotic index was detected by TUNEL staining. Western blot and immunoprecipitation analyses were used to detect the expression levels and the association between S100A4 and P53. H₂O₂ treatment led to oxidative stress injury in the cultured vascular endothelial cells, a decrease in the cell viability and an increase in the rate of apoptosis of vascular endothelial cells compared with the negative control group. Exogenous S100A4 serves a significant function against oxidative stress injury (P<0.05), increasing the viability and attenuating the apoptotic rate of endothelial cells. Western blotting results suggested that the protein levels of S100A4 and P53 increased subsequent to oxidative stress injury and that exogenous S100A4 increased the expression of P53 in the cytoplasm and decreased the expression of P53 in nucleus. The immunoprecipitation assay results revealed a protein-protein interaction between S100A4 and P53. These results suggested that rat recombinant S100A4 serves an anti-apoptotic function in oxidative stress injury. This effect of S100A4 is mediated, at least in part, via the inhibition of the translocation of P53 to the nucleus.

Expression and modulation of S100A4 protein by human mast cells

S100A4 protein is expressed in fibroblasts during tissue remodelling and in cancer stem cells and it induces the metastatic spread of tumor cells. In mast cells (MCs) S100A4 have been found in some pathological conditions, but its function in normal MCs remains to be described. The purpose of this study was to characterize the cellular localization of the S100A4 protein in MCs of human tissues with inflammatory or tumor disorders and, to determine the consequence of reducing its expression in MC response. We found that tissue resident MCs stained positive to S100A4. Both human HMC-1 cell line and resting CD34⁺-derived MCs expressed S100A4, whose levels were differentially modulated upon MC activation. Downregulation of the S100A4 protein resulted in MC growth inhibition, enhanced apoptosis and deregulation of MMP-1 and MMP-10 production. Our results suggest that S100A4 is also playing a role in the MC life cycle and functions.

S100A4 promotes colon inflammation and colitis-associated colon tumorigenesis

S100A4 plays important roles in tumor development and metastasis, but its role in regulating inflammation and colitis-associated tumorigenesis has not been well characterized. Here, we report that S100A4 expression was increased in azoxymethane (AOM) and dextran sulfate sodium (DSS) induced colorectal cancer (CRC) in mice. After AOM/DSS treatment, both S100A4-TK mice with the selective depletion of S100A4-expressing cells and S100A4-deficient (S100A4^−/−) mice developed fewer and smaller tumors than wild-type (WT) control littermates. Furthermore, S100A4^−/− mice were resistant to DSS-induced colitis, reduced infiltration of macrophages, and the diminished production of proinflammatory cytokines. Further studies revealed that reduced colon inflammation and colorectal tumor development in S100A4^−/− mice were partly due to the dampening of nuclear factor (NF)-κB activation in macrophages. Furthermore, the administration of a neutralizing S100A4 antibody to WT mice significantly decreased AOM/DSS-induced colon inflammation and tumorigenesis. These results indicate that S100A4 amplifies an inflammatory microenvironment that promotes colon tumorigenesis and provides a promising therapeutic strategy for treatment of inflammatory bowel disease and prevention of colitis-associated colorectal carcinogenesis.

RAGE Deletion Confers Renoprotection by Reducing Responsiveness to Transforming Growth Factor-β and Increasing Resistance to Apoptosis

Signaling via the receptor of advanced glycation end products (RAGE)-though complex and not fully elucidated in the setting of diabetes-is considered a key injurious pathway in the development of diabetic nephropathy (DN). We report here that RAGE deletion resulted in increased expression of fibrotic markers (collagen I and IV, fibronectin) and the inflammatory marker MCP-1 in primary mouse mesangial cells (MCs) and in kidney cortex. RNA sequencing analysis in MCs from RAGE^-/- and wild-type mice confirmed these observations. Nevertheless, despite these gene expression changes, decreased responsiveness to transforming growth factor-β was identified in RAGE^-/- mice. Furthermore, RAGE deletion conferred a more proliferative phenotype in MCs and reduced susceptibility to staurosporine-induced apoptosis. RAGE restoration experiments in RAGE^-/- MCs largely reversed these gene expression changes, resulting in reduced expression of fibrotic and inflammatory markers. This study highlights that protection against DN in RAGE knockout mice is likely to be due in part to the decreased responsiveness to growth factor stimulation and an antiapoptotic phenotype in MCs. Furthermore, it extends our understanding of the role of RAGE in the progression of DN, as RAGE seems to play a key role in modulating the sensitivity of the kidney to injurious stimuli such as prosclerotic cytokines.

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.

Attenuation of cancer-initiating cells stemness properties by abrogating S100A4 calcium binding ability in head and neck cancers

S100A4 is a calcium-binding protein capable of promoting epithelial-mesenchymal transition. Previously, we have demonstrated that S100A4 is required to sustain the head and neck cancer-initiating cells (HN-CICs) subpopulation. In this study, to further investigate the molecular mechanism, we established the head and neck squamous cell carcinoma (HNSCC) cell lines stably expressing mutant S100A4 proteins with defective calcium-binding sites on either N-terminal (NM) or C-terminal (CM), or a deletion of the last 15 amino-acid residues (CD). We showed that the NM, CM and CD harboring sphere cells that were enriched with HN-CICs population exhibited impaired stemness and malignant properties in vitro, as well as reduced tumor growth ability in vivo. Mechanistically, we demonstrated that mutant S100A4 proteins decreased the promoter activity of Nanog, likely through inhibition of p53. Moreover, the biophysical analyses of purified recombinant mutant S100A4 proteins suggest that both NM and CM mutant S100A4 were very similar to the WT S100A4 with subtle difference on the secondary structure, and that the CD mutant protein displayed the unexpected monomeric form in the solution phase.Taken together, our results suggest that both the calcium-binding ability and the C-terminal region of S100A4 are important for HN-CICs to sustain its stemness property and malignancy, and that the mechanism could be mediated by repressing p53 and subsequently activating the Nanog expression.

S100A4 promotes lung tumor development through β-catenin pathway-mediated autophagy inhibition

Autophagy has emerged as a critical pathway in tumor development. S100A4 plays important roles in tumor metastasis, but its role in regulating autophagy has not been well characterized. In this study, we found that S100A4 was significantly upregulated in lung adenocarcinoma tissues. Clinical investigation demonstrated that high expression level of S100A4 was associated with tumor size and advanced tumor grades of lung adenocarcinoma patients. Moreover, our results revealed that extracellular S100A4 or overexpression of S100A4 inhibited starvation-induced autophagy and promoted cell proliferation in lung cancer cells in vitro; whereas small interfering RNA (siRNA)-mediated suppression of S100A4 increased autophagy and reduced cell viability in both A549 and LLC cells. Additionally, S100A4 inhibited starvation-induced autophagy to promote tumor cell viability via the Wnt pathway. Increased expression of β-catenin consistently led to a decreased LC3-II protein abundance. Further, the inhibitory effect of S100A4 on autophagy and its promotion role in cell proliferation was abolished in A549 and LLC cells using the receptor for advanced glycation end products (RAGE)-specific inhibitor (FPS-ZM1). S100A4-deficient mice showed retarded tumor development. This effect was well correlated with increased expression of autophagy markers. Our findings demonstrate that S100A4 promotes lung tumor development through inhibiting autophagy in a β-catenin signaling and S100A4 receptor RAGE-dependent manner, which provides a novel mechanism of S100A4-associated promotion of tumor development.

Interplay between Trx-1 and S100P promotes colorectal cancer cell epithelial-mesenchymal transition by up-regulating S100A4 through AKT activation

We previously reported a novel positive feedback loop between thioredoxin‐1 (Trx‐1) and S100P, which promotes the invasion and metastasis of colorectal cancer (CRC). However, the underlying molecular mechanisms remain poorly understood. In this study, we examined the roles of Trx‐1 and S100P in CRC epithelial‐to‐mesenchymal transition (EMT) and their underlying mechanisms. We observed that knockdown of Trx‐1 or S100P in SW620 cells inhibited EMT, whereas overexpression of Trx‐1 or S100P in SW480 cells promoted EMT. Importantly, S100A4 and the phosphorylation of AKT were identified as potential downstream targets of Trx‐1 and S100P in CRC cells. Silencing S100A4 or inhibition of AKT phosphorylation eliminated S100P‐ or Trx‐1‐mediated CRC cell EMT, migration and invasion. Moreover, inhibition of AKT activity reversed S100P‐ or Trx‐1‐induced S100A4 expression. The expression of S100A4 was higher in human CRC tissues compared with their normal counterpart tissues and was significantly correlated with lymph node metastasis and poor survival. The overexpression of S100A4 protein was also positively correlated with S100P or Trx‐1 protein overexpression in our cohort of CRC tissues. In addition, overexpression of S100P reversed the Trx‐1 knockdown‐induced inhibition of S100A4 expression, EMT and migration and invasion in SW620 cells. The data suggest that interplay between Trx‐1 and S100P promoted CRC EMT as well as migration and invasion by up‐regulating S100A4 through AKT activation, thus providing further potential therapeutic targets for suppressing the EMT in metastatic CRC.

S100A4 drives non-small cell lung cancer invasion, associates with poor prognosis, and is effectively targeted by the FDA-approved anti-helminthic agent niclosamide

S100A4 (metastasin-1), a metastasis-associated protein and marker of the epithelial to mesenchymal transition, contributes to several hallmarks of cancer and has been implicated in the progression of several types of cancer. However, the impacts of S100A4 signaling in lung cancer progression and its potential use as a target for therapy in lung cancer have not been properly explored. Using established lung cancer cell lines, we demonstrate that S100A4 knockdown reduces cell proliferation, invasion and three-dimensional invasive growth, while overexpression of S100A4 increases invasive potential. In patient-derived tissues, S100A4 is preferentially elevated in lung adenocarcinoma. This elevation is associated with lymphovascular invasion and decreased overall survival. In addition, depletion of S100A4 by shRNA inhibits NF-κB activity and decreases TNFα-induced MMP9 expression. Furthermore, inhibition of the NF-κB/MMP9 axis decreases lung carcinoma invasive potential. Niclosamide, a reported inhibitor of S100A4, blocks expression and function of S100A4 with a reduction in proliferation, invasion and NF-κB-mediated MMP9 expression. Collectively, this study highlights the importance of the S100A4/NF-κB/MMP9 axis in lung cancer invasion and provides a rationale for targeting S100A4 to combat lung cancer.

Cancer-associated S100P protein binds and inactivates p53, permits therapy-induced senescence and supports chemoresistance

S100P belongs to the S100 family of calcium-binding proteins regulating diverse cellular processes. Certain S100 family members (S100A4 and S100B) are associated with cancer and used as biomarkers of metastatic phenotype. Also S100P is abnormally expressed in tumors and implicated in migration-invasion, survival, and response to therapy. Here we show that S100P binds the tumor suppressor protein p53 as well as its negative regulator HDM2, and that this interaction perturbs the p53-HDM2 binding and increases the p53 level. Paradoxically, the S100P-induced p53 is unable to activate its transcriptional targets hdm2, p21^WAF, and bax following the DNA damage. This appears to be related to reduced phosphorylation of serine residues in both N-terminal and C-terminal regions of the p53 molecule. Furthermore, the S100P expression results in lower levels of pro-apoptotic proteins, in reduced cell death response to cytotoxic treatments, followed by stimulation of therapy-induced senescence and increased clonogenic survival. Conversely, the S100P silencing suppresses the ability of cancer cells to survive the DNA damage and form colonies. Thus, we propose that the oncogenic role of S100P involves binding and inactivation of p53, which leads to aberrant DNA damage responses linked with senescence and escape to proliferation. Thereby, the S100P protein may contribute to the outgrowth of aggressive tumor cells resistant to cytotoxic therapy and promote cancer progression.

Involvement of AF1q/MLLT11 in the progression of ovarian cancer

The functional role of AF1q/MLLT11, an oncogenic factor involved in a translocation t(1;11)(q21;q23) responsible for acute myeloid leukaemia, has been investigated in hematological and solid malignancies and its expression was found to be linked to tumor progression and poor clinical outcome. In addition to its oncogenic function, AF1q has been shown to play a role in the onset of basal and drug-induced apoptosis in cancer cells of different histotypes, including ovarian cancer. Through in vitro, ex vivo, and in silico approaches, we demonstrated here that AF1q is also endowed with protumorigenic potential in ovarian cancer. In ovarian cancer cell lines, stable AF1q overexpression caused activation of epithelial-to-mesenchymal transition and increased motility/migratory/invasive abilities accompanied by gene expression changes mainly related to Wnt signaling and to signaling pathways involving in ERK/p38 activation. The potential role of AF1q in ovarian cancer progression was confirmed by immunohistochemical and in silico analyses performed in ovarian tumor specimens which revealed that the protein was absent in normal ovarian epithelium and became detectable when atypical proliferation was present. Moreover, AF1q was significantly lower in borderline ovarian tumors (i.e., tumors of low malignant potential without stromal invasion) than in invasive tumors, thus corroborating the association between high AF1q expression and increased migratory/invasive cell behavior and confirming its potential role in ovarian cancer progression. Our findings demonstrated, for the first time, that AF1q is endowed with protumorigenic activity in ovarian cancer, thus highlighting a dual behavior (i.e., protumorigenic and proapoptotic functions) of the protein in the malignancy.

Cardioprotection by the transfer of coronary effluent from ischaemic preconditioned rat hearts: identification of cardioprotective humoral factors

Ischaemic preconditioning (IPC) provides myocardial resistance to ischaemia/reperfusion (I/R) injuries. The protection afforded by IPC is not limited to the target tissue but extends to remote tissues, suggesting a mechanism mediated by humoral factors. The aim of the present study was to identify the humoral factors that are responsible for the cardioprotection induced by the coronary effluent transferred from IPC to naïve hearts. Isolated rat hearts were submitted to IPC (three cycles of 5 min I/R) before 30-min global ischaemia and 60-min reperfusion. The coronary effluent (Efl_IPC) collected during IPC was fractionated by ultrafiltration in different molecular weight ranges (<3, 3-5, 5-10, 10-30, 30-50, and >50 kDa) and evaluated for cardioprotective effects by perfusion before I/R in naïve hearts. Only the <3, 5-10 and <10 kDa fractions of hydrophobic eluate reduced I/R injuries. The cardioprotective effect of the 5-10 fraction was blocked by K_ATP channel blockers and a PKC inhibitor. An Efl_IPC proteomic analysis revealed 14 cytoprotection-related proteins in 4-12 kDa peptides. HSP10 perfusion protected the heart against I/R injuries. These data provide insights into the mechanisms of cardioprotection in humoral factors released by IPC. Cardioprotection is afforded by hydrophobic peptides in the 4-12 kDa size range, which activate pathways that are dependent on PKC and K_ATP. Fourteen 4-12 kDa peptides were identified, suggesting a potential therapeutic role for these molecules in ischaemic diseases. One of these, HSP10, identified by mass spectrometry, reduced I/R injuries and may be a potential candidate as a therapeutic target.

Calcium-binding protein S100A4 confers mesenchymal progenitor cell fibrogenicity in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a prevalence of 1 million persons worldwide. The fibrosis spreads from affected alveoli into contiguous alveoli and leads to death by asphyxiation. We previously discovered that the IPF lung harbors fibrogenic mesenchymal progenitor cells (MPCs) that serve as a cell of origin for disease-mediating myofibroblasts. In a prior genomewide transcriptional analysis, we found that IPF MPCs displayed increased expression of S100 calcium-binding A4 (S100A4), a protein linked to cancer cell proliferation and invasiveness. Here, we have examined whether S100A4 mediates MPC fibrogenicity. Ex vivo analysis revealed that IPF MPCs had increased levels of nuclear S100A4, which interacts with L-isoaspartyl methyltransferase to promote p53 degradation and MPC self-renewal. In vivo, injection of human IPF MPCs converted a self-limited bleomycin-induced mouse model of lung fibrosis to a model of persistent fibrosis in an S100A4-dependent manner. S100A4 gain of function was sufficient to confer fibrotic properties to non-IPF MPCs. In IPF tissue, fibroblastic foci contained cells expressing Ki67 and the MPC markers SSEA4 and S100A4. The expression colocalized in an interface region between myofibroblasts in the focus core and normal alveolar structures, defining this region as an active fibrotic front. Our findings indicate that IPF MPCs are intrinsically fibrogenic and that S100A4 confers MPCs with fibrogenicity.

Underlying Mechanisms for Distant Metastasis - Molecular Biology

BACKGROUND

The formation of distant metastases constitutes a complex process with a variety of different genes and pathways involved. To improve patient survival, it is necessary to understand the underlying mechanisms of metastasis to allow for targeted intervention.

METHODS

This review provides an overview of the general concepts of metastasis, focusing on the most important genes and pathways involved and on interventional strategies.

RESULTS

Cancer cells undergo different steps to form metastasis: most prominently, local invasion, intravasation, survival in the circulation, arrest at a distant organ site and extravasation, micrometastasis formation, and metastatic colonization. In order to pass these steps, different molecular pathways are of major importance: EGF/RAS/RAF/MEK/ERK, PI3K/Akt/mTOR, HGF/Met, Wnt/β-catenin, and VEGF signaling. The HGF/Met regulator MACC1 and the Wnt signaling target S100A4 have been shown to play a major role in the metastatic process. Each gene and pathway provides an opportunity for therapeutic intervention.

CONCLUSION

Since metastasis represents a highly limiting factor in cancer therapy causing 90% of cancer deaths, it is imperative to reveal the underlying mechanisms. This is fundamental for uncovering prognostic markers and new targeted therapy options.

Knockdown of S100A4 blocks growth and metastasis of anaplastic thyroid cancer cells in vitro and in vivo

Anaplastic thyroid cancer (ATC) is a locally aggressive type of thyroid tumor with high rate of distant metastases. It is often incurable because it does not respond to radioiodine, radiotherapy, or chemotherapy. With conventional treatment, the median survival is about 6 months; therefore, new treatment options are needed. S100A4 is a calcium-binding protein related to the metastatic potential of carcinoma. Previous study has found S100A4 was overexpressed in human papillary thyroid carcinomas (PTC) tissues, and overexpression of S100A4 is associated with thyroid tumour invasion and metastasis. In the present study, we first examined S100A4 protein expression in 14 ATC tissues, 20 PTC tissues and 14 normal thyroid tissue by immunohistochemistry analysis. We then knocked down of S100A4 expression by RNA interference (S100A4 siRNA) and investigated its effects on growth and metastasis in two human ATC cell lines 8505C (BRAFV600E) and Cal-62 (BRAFwt) in vitro and in vivo. S100A4 and BRAFV600E protein expression was evaluated by western blot assay and immunohistochemistry analysis. Using immunohistochemistry, we found that high levels of S100A4 were detected in ATC specimens and PTC specimens. No S100A4 staining was observed in normal thyroid tissues. S100A4 siRNA significantly decreased proliferation and increased apoptosis, and inhibited the invasive potential of the two cells in vitro. In addition, S100A4 siRNA could effectively inhibit BRAFV600E expression in the 8505C cells, and treatment with 100 ng/ml human recombinant BRAF V600E in S100A4 siRNA/8505C cells could partly restore its proliferative and invasive ability. Results of implantation in vivo showed S100A4 shRNA could significantly inhibit abdominal cavity metastasis and tumor growth in vivo. Furthermore, knockdown of S100A4 has significant role on invasion, metastasis and growth inhibition in the 8505C cells than that of in the Cal-62 cells. These results support the hypothesis that S100A4 contributes significantly to growth and metastasis, and that down-regulation of S100A4 expression decreases the metastatic potential of ATC cells. Furthermore, down-regulation of S100A4 expression is more marked in BRAFV600E cells than that of in the BRAFwt cells.