12-O-tetradecanoylphorbol-13-acetate promotes breast cancer cell motility by increasing S100A14 level in a Kruppel-like transcription factor 4 (KLF4)-dependent manner

Non-genotoxic carcinogens (TPA and mezerein) activate tumourous transformation through miR let-7-mediated Hmga2 expression in Bhas42 cells

A Bhas42 cell transformation assay is a method used to detect the tumour-promoting activities of chemicals. However, the mechanisms underlying tumour transformations mediated by non-genotoxic carcinogens (NGCs) are poorly understood. This study aimed to examine the correlation between 12-O-tetradecanoylphorbol 13-acetate (TPA) or mezerein and the initiation of tumourous transformations by epigenetic regulation in Bhas42 cells. We found that TPA and mezerein prompted tumourous transformations by stimulating cell proliferation and migration in Bhas42 cells. Furthermore, we observed alterations in the expression levels of 134 genes, with 87 genes being upregulated and 47 genes being downregulated, following exposure to either TPA or mezerein. Among the differentially regulated genes, we identified 17 upregulated genes and 8 downregulated genes corresponding to differentially expressed genes in TNM [primary tumour (T), regional nodes (N), and metastasis (M)]. Importantly, we found that TPA and mezerein triggered the expression of Hmga2 and Ezh2 by loss of miRNA let-7 (miR let-7) in Bhas42 cells. Finally, the microRNA (miRNA) mimic of let-7 prevented the TPA- and mezerein-induced activation of Hmga2 and Ezh2 in Bhas42 cells. Our findings reveal a connection between tumourous transformations and the epigenetic regulator miR let-7 in NGCs, such as TPA and mezerein in Bhas42 cells. This highlights miR let-7 as a promising therapeutic target for mitigating tumourous transformations induced by NGCs.

KLF4: a multifunctional nexus connecting tumor progression and immune regulation

Krüppel-like factors (KLFs) regulate various biological processes such as cell proliferation, migration, invasion, and differentiation as gene transcription factors. Signaling pathways which mediated by KLF4 and KLF4 have a sophisticated role in tumors due to multiple factors, including the types or stage of tumors. KLF4 plays a promoter role in tumorigenesis and development, or tumor suppressor as a context-dependent anti- and pro-inflammatory factor. KLF4 over-expression increases CD8+T cell differentiation and enhances the antitumor immunity. This review aims to provide information about the relationship of KLF4 in immunity with tumors and to guide the future study.

Role of Calcium in an Experimental Breast Cancer Model Induced by Radiation and Estrogen

Background: Breast cancer, a global health challenge, significantly impacts women worldwide, causing morbidity, disability, and mortality. Objectives: To analyze the role of genes encoding S100 calcium-binding proteins and their relationship with radiation as possible markers in breast carcinogenesis. Methods: The normal MCF-10F cell line was used to study the role of ionizing radiation and estrogen to induce distinct stages of malignancy giving rise to an in vitro experimental breast cancer model. Results: Analysis of an Affymetrix system revealed that the gene expression levels of the S100 calcium-binding protein P (S100P), the S100 calcium-binding protein A14 (S100A14), and the S100 calcium-binding protein A2 (S100A2) were greater in the Tumor2 than the non-tumorigenic Alpha3 or the tumorigenic Alpha5 cell lines; however, the S100 calcium-binding protein A8 (S100A8) and the S100 calcium-binding protein A9 (S100A9) expression levels were higher in A5 than T2 and A3 cell lines. A significant positive association was found between the estrogen receptor alpha gene (ESR1) and S100A14 in Basal and Her2 patients. The association between ESR1 and S100A8 and S100A9 expression levels was positive in Basal patients but negative in Her2, Luminal A, and Luminal B. S100P and S100A14 expression levels were higher in tumor tissues than in normal ones. The estrogen receptor status was positive in patients with high levels of the S10014 gene, but negative in S100A2, S100A8, and S100A9 expression levels. Conclusion: Cell dependence needs to be considered while designing new breast cancer treatments since gene signatures might vary depending on the type of tumor.

KLF4 Induces Colorectal Cancer by Promoting EMT via STAT3 Activation

OBJECTIVE

Krüppel-like factor 4 (KLF4) has been demonstrated to exert a pro-carcinogenic effect in solid tissues. However, the precise biological function and underlying mechanisms in colorectal cancer (CRC) remains elucidated.

AIMS

To investigate whether KLF4 participates in the proliferation and invasion of CRC.

METHODS

The expression of KLF4 was investigated using immunohistochemistry and immunoblotting. The clinical significance of KLF4 was evaluated. Furthermore, the effect of inhibiting or overexpressing KLF4 on tumor was examined. Immunoblotting and qPCR were used to detect Epithelial-mesenchymal transition-related proteins levels. Additionally, the molecular function of KLF4 is related to the STAT3 signaling pathway and was determined through JASPAR, GSEA analysis, and in vitro experiments.

RESULTS

KLF4 exhibits down-regulated expression in CRC and is part of the vessel invasion, TNM stage, and worse prognosis. In vitro studies have shown that KLF4 promotes cellular proliferation and invasion, as well as EMT processes. Xenograft tumor models confirmed the oncogenic role of KLF4 in nude mice. Furthermore, GSEA and JASPAR databases analysis reveal that the binding of KLF4 to the signal transducer and activator of transcription 3 (STAT3) promoter site induces activation of p-STAT3 signaling. Subsequent targeting of STAT3 confirmed its pivotal role in mediating the oncogenic effects exerted by KLF4.

CONCLUSION

The study suggests that KLF4 activates STAT3 signaling, inducing epithelial-mesenchymal transition, thereby promoting CRC progression.

Prolonged continual consumption of oregano herb interferes with the action of steroid hormones and several drugs, and effects signaling across the brain-gut axis

Herbs and spices have been used throughout human history for their medicinal qualities. The advent of cheap and readily available medicines have lessened the need for herbs and spices as traditional medicines, however, they are rapidly regaining popularity with rising interest of the general population in health, natural products and nutrition. The need for alternative medicines with antimicrobial properties, such as herbs and spices, has also come to the forefront in light of the recent bans of antibiotic use in the livestock industry, including the poultry industry. This large scale use presents an opportunity to observe nutrigenomic effects of prolonged use of herbs on a substantial number of birds fed high concentrations of these products throughout the production cycle. In this manuscript, we investigated the transcriptional effect of continual prolonged oregano supplementation on chicken ileum gene expression. Based on ileum transcriptomics, we report that continual supplementation with 2% oregano altered microbiota-gut-brain axis signalling, rearranged cancer susceptibility towards reduced steroid hormone-related cancers and altered expression of genes targeted by many registered drugs, thus likely affecting their efficiency and side effects. Transcriptional toxicology analysis indicated significant activation of Ventricular Septal Defect and Congenital Heart Disease categories. Our results, counter the notion that natural products such as oregano have the potential for little to no side-effects as they are "natural". The nutrigenomic approach of understanding benefits and side effects of the food we eat, can revolutionize disease management and therapy and have special significance in designing the diets for individuals or livestock with known disease predispositions.

Recent Discoveries on the Involvement of Krüppel-Like Factor 4 in the Most Common Cancer Types

Krüppel-like factor 4 (KLF4) is a transcription factor highly conserved in evolution. It is particularly well known for its role in inducing pluripotent stem cells. In addition, KLF4 plays many roles in cancer. The results of most studies suggest that KLF4 is a tumor suppressor. However, the functioning of KLF4 is regulated at many levels. These include regulation of transcription, alternative splicing, miRNA, post-translational modifications, subcellular localization, protein stability and interactions with other molecules. Simple experiments aimed at assaying transcript levels or protein levels fail to address this complexity and thus may deliver misleading results. Tumor subtypes are also important; for example, in prostate cancer KLF4 is highly expressed in indolent tumors where it impedes tumor progression, while it is absent from aggressive prostate tumors. KLF4 is important in regulating response to many known drugs, and it also plays a role in tumor microenvironment. More and more information is available about upstream regulators, downstream targets and signaling pathways associated with the involvement of KLF4 in cancer. Furthermore, KLF4 performs critical function in the overall regulation of tissue homeostasis, cellular integrity, and progression towards malignancy. Here we summarize and analyze the latest findings concerning this fascinating transcription factor.

A Clinicopathological Analysis of S100A14 Expression in Colorectal Cancer

BACKGROUND/AIM

The calcium-binding protein S100A14 is involved in processes related to tumorigenesis and tumor propagation, such as proliferation, apoptosis, motility and invasiveness. Our aim was to investigate its role in colorectal cancer.

PATIENTS AND METHODS

One hundred and seven patients (65 men and 42 women) were included in this study. They had been diagnosed with colorectal cancer and undergone complete resection of their primary tumor. Tissue samples from archival blocks of their normal and malignant colorectal tissues were used for immunohistochemical assessment of S100A14 expression. S100A14 levels were evaluated using image analysis and associated with various clinicopathological parameters and prognosis.

RESULTS

S100A14 expression was reduced in malignant tissues when compared to normal intestinal mucosa in cases of T3-T4 tumors (p=0.017). Moreover, as far as S100A14 levels in malignant tissues are concerned, they were lower in T3-T4 tumors (p=0.001), N2 disease (p=0.034) and M1 disease (p=0.019). Finally, very high S100A14 production (>75^th percentile) was associated with shorter disease-specific (HR=3.584, p=0.045) and relapse-free survival (HR=4.527, p=0.007) in multivariate survival analysis.

CONCLUSION

S100A14 expression is decreased in advanced colorectal cancer. However, cases with very high S100A14 levels have a worse survival.

TRAF7 enhances ubiquitin-degradation of KLF4 to promote hepatocellular carcinoma progression

The tumor necrosis factor receptor-associated factor 7 (TRAF7) is a component of the tumor necrosis factor alpha (TNF-α)/nuclear factor kappa B (NF-κB) pathway and is a putative E3-ubiquitin ligase. Based on importance of chronic inflammation in hepatocellular carcinoma (HCC), we investigated the biological effects and the molecular mechanisms of deregulated TRAF7 signaling in HCC. Our results showed that high TRAF7 expression in HCC samples was inversely associated with Krüppel-like factor 4 (KLF4) expression and the prognosis of HCC patients. TRAF7 could degrade KLF4 protein through ubiquitin by interacting with its N-terminus. The up-regulation of TRAF7 promoted HCC cell migration and invasion in vivo and in vitro, and TRAF7 knockdown had the opposite effects. Restoration of KLF4 abrogated the motility promotion induced by TRAF7. TRAF7 promotes HCC cell motility through inducing KLF4 protein turnover.

ATXN3 promotes breast cancer metastasis by deubiquitinating KLF4

Krüppel-like factor 4 (KLF4) is an important transcription factor implicated in a variety of essential cellular processes. Aberrant KLF4 expression is closely related to tumourigenesis and tumour progression. The rapid turnover of the KLF4 protein indicates an important role for the posttranslational modifications (PTMs) of KLF4. To date, E3 ligases mediating KLF4 ubiquitination have been widely reported, yet the deubiquitinating mechanism of KLF4 remains largely unknown. We screened a library of 65 deubiquitinating enzymes and identified ATXN3 as a deubiquitinating enzyme of KLF4. Subsequent immunoprecipitation assays confirmed that ATXN3 bound to KLF4, mediating the deubiquitination and stabilization of KLF4 protein levels. Furthermore, we demonstrated that ATXN3 promoted breast cancer cell metastasis via KLF4 in vitro and in vivo. Finally, the protein expression analysis of human breast cancer specimens demonstrated that ATXN3 significantly correlated with KLF4. High ATXN3/KLF4 expression was associated with a poor prognosis in breast cancer patients. Collectively, we identified ATXN3 as a novel deubiquitinating enzyme of KLF4, providing a new explanation for breast cancer metastasis, and proposed ATXN3 as a potential target for breast cancer metastasis treatment.

Differential effects of luteolin and its glycosides on invasion and apoptosis in MDA-MB-231 triple-negative breast cancer cells

Luteolin is known to have anticancer activity in various cancers. Recent studies have shown that luteolin glycosides, such as luteolin-8-C-β-fucopyranoside, 7-methoxy-luteolin-8-C-β-(6- deoxyxylopyranos-3-uloside) and luteolin-8-C-β-d-glucopyranoside, flavonoids that are present in Arthraxon hispidus, exert antimigratory and anti-invasive effects, but no cytotoxic effect in estrogen receptor-positive MCF7 breast cancer cells. In the present study, we further investigated and compared differential effects of luteolin and its glycosides in MDA-MB-231 triple-negative breast cancer cells. Luteolin suppressed the expression of matrix metalloproteinase-9 and inhibited migration and invasion in MDA-MB-231 cells treated with the tumor promotor 12-O-tetradecanoylphorbol-13-acetate at non-cytotoxic concentrations (0, 5, and 10 μM). Furthermore, at cytotoxic concentrations (20 and 40 μM), luteolin induced apoptosis via extrinsic and intrinsic pathways in MDA-MB-231 cells. However, luteolin glycosides did not exert any cytotoxic, antimigratory, or anti-invasive effect in MDA-MB-231 cells. In brief, luteolin had both antimetastatic and cytotoxic effects on MDA-MB-231 cells, whereas luteolin glycosides had no effect on this cell line. Taking together the present results and our previous findings on the differential effects of luteolin and its glycosides on MDA-MB-231 and MCF-7 breast cancer cells, luteolin and its glycosides can be suggested as a potential candidate for breast cancer therapy.

Identification of S100A14 as a metastasis-promoting molecule in a murine organotropic metastasis model

Cancer metastasis shows great diversity in target organs, routes and molecular mechanisms depending on the type of cancer and even on the individual patients. To identify key molecules involved in metastasis, we constructed a murine model system including multiple sublines with different organotropism and pathways of metastasis. We selected metastatic sublines from a murine mammary tumor cell line MCH66. Using this model, we extracted metastasis-related molecules by gene expression screening methods and verified their metastasis-promoting effects by gene knockdown or overexpression experiments. For the candidates promoting metastasis, we analyzed molecular functions involved in metastasis: cell growth, motility and invasive activity. We established a metastasis model including low metastatic sublines (66C8, 66LM, 66-4) and highly metastatic counterparts with various organotropism, such as to the lung (66Lu10), liver (HM-KAN5) and general organs (66HM and its clones: HM1-6 and HM1-7). The sublines basically exhibited the invasion-independent metastasis pathway characterized by endothelial cell-covered tumor emboli, whereas 66HM and HM-KAN5 showed an alternative metastasis pathway based on invasion in part and in whole, respectively. Comprehensive gene analysis extracted several molecular candidates responsible for metastasis. S100A14 was identified as one of the promissing candidates promoting lung-metastasis, which was verified by gene knockdown experiments in vivo. In addition, in vivo and in vitro functional analyses demonstrated that S100A14 enhanced scattering, motility and invasiveness of mouse tumor cells. Our model system may be adaptable to the diversity of metastasis in human cancers and useful for exploring the molecular mechanism responsible for metastasis.

Natural products: An upcoming therapeutic approach to cancer

Cancer is one of the leading causes of death across the world. Different environmental and anthropogenic factors initiate mutations in different functional genes of growth factors and their receptors, anti-apoptotic proteins, self-renewal developmental proteins, tumor suppressors, transcription factors, etc. This phenomenon leads to altered protein homeostasis of the cell which in turn induces cancer initiation, development, progression and survival. From ancient times various natural products have been used as traditional medicine against different diseases. Natural products are readily applicable, inexpensive, accessible and acceptable therapeutic approach with minimum cytotoxicity. As most of the target-specific anticancer drugs failed to achieve the expected result so far, new multi-targeted therapies using natural products have become significant. In this review, we have summarized the efficacy of different natural compounds against cancer. They are capable of modulating cancer microenvironment and diverse cell signaling cascades; thus playing a major role in combating cancer. These compounds are found to be effective against several signaling pathways, mainly cell death pathways (apoptosis and autophagy) and embryonic developmental pathways (Notch pathway, Wnt pathway and Hedgehog pathway). This review article is expected to be helpful in understanding the recent progress of natural product research for the development of anticancer drug.

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.

Overexpression of S100A14 contributes to malignant progression and predicts poor prognosis of lung adenocarcinoma

BACKGROUND

S100A14 is a member of the S100 calcium-binding protein family that exerts important phenotypic effects on cell proliferation, apoptosis, differentiation, and motility. However, the functional role and potential clinical significance of S100A14 in lung adenocarcinoma has not yet been clarified.

METHODS

We analyzed genomic alterations of S100A14 using The Cancer Genome Atlas lung adenocarcinoma genomic dataset. S100A14 displayed significant copy number amplification in lung adenocarcinoma. We detected S100A14 expression in lung adenocarcinoma and analyzed the correlation between S100A14 expression and clinicopathological characteristics.

RESULTS

Immunohistochemical analysis showed that S100A14 expression was obviously upregulated in lung adenocarcinoma tissues compared to matched normal counterparts. Statistical analysis revealed that S100A14 expression strongly correlated with poor differentiation, metastasis, stage, smoking, and EGFR mutation. Furthermore, our data indicated that S100A14 serum levels were higher in lung adenocarcinoma patients than healthy controls. Intriguingly, S100A14 serum levels were related to distant metastasis (P = 0.028). High S100A14 expression was significantly associated with overall (P = 0.0016) and post progression (P = 0.039) survival. In addition, we investigated the biological functions of S100A14 in lung adenocarcinoma cell lines. The results demonstrated that S100A14 promoted cell migration and invasion of SPCA1 and Glc-82 cells.

CONCLUSIONS

S100A14 increases the motility of lung adenocarcinoma cells, and might be a diagnostic and prognostic serum biomarker and potential therapeutic target for lung adenocarcinoma.

A review of S100 protein family in lung cancer

S100 protein family, representing 25 relatively small calcium binding proteins, has been reported to be involved in multiple stages of tumorigenesis and progression. These proteins are considered having potential value to be adopted as novel biomarkers in the detection and accurate prediction of many kinds of tumors, including lung cancer. As the one having the highest morbidity and mortality among all cancers, lung carcinoma is still occult for detection, especially at early stage. S100 proteins take participation in the lung neoplasia through playing intracellular and/or extracellular functions, therefore getting involved in a variety of biological processes such as differentiation, proliferation, and migration. A few members have also been testified to modulate TGF-β/Smad-3 mediated transcriptional activity of target genes involved in tumor promotion. In addition to that, a number of proteins in this family have already been reported to experience an abnormal trend in lung cancer at cell, serum and tissue levels. Thus, S100 proteins may serve as effective biomarkers for suspected or already diagnosed lung cancer patients. In future, S100 protein family might be applied as therapeutic targets in clinical treatment of lung cancer. In this review, we firstly summed up the biological and clinical evidence connecting S100 proteins and lung cancer, which has not been summarized before.

Antioxidant Potential of Selected Korean Edible Plant Extracts

This study aimed to evaluate the antioxidant activity of various plant extracts. A total of 94 kinds of edible plant extracts obtained from the Korea Plant Extract Bank were screened for cytotoxicity, following which the total phenolic content of 24 shortlisted extracts was determined. Of these, extracts from three plants, namely, Castanea crenata (CC) leaf, Camellia japonica (CJ) fruit, and Viburnum dilatatum (VD) leaf, were examined for antioxidant capabilities by measuring radical scavenging activity, ferric reducing/antioxidant power, and lipid peroxidation inhibitory activity. In addition, cellular antioxidant activities of the three extracts were assessed by a cell-based dichlorofluorescein assay and antioxidant response element (ARE) reporter activity assay. The results demonstrated that all three extracts concentration-dependently scavenged free radicals, inhibited lipid peroxidation, reduced the cellular level of reactive oxygen species, and increased ARE-luciferase activity, indicating antioxidant enzyme-inducing potential. In particular, CJ extract showed significantly greater antioxidative activity and antimigratory effect in a breast cancer cell line compared to CC and VD extracts. Hence, CJ extract deserves further study for its in vivo functionality or biologically active constituents.

KCNN4 and S100A14 act as predictors of recurrence in optimally debulked patients with serous ovarian cancer

Approximately 50-75% of patients with serous ovarian carcinoma (SOC) experience recurrence within 18 months after first-line treatment. Current clinical indicators are inadequate for predicting the risk of recurrence. In this study, we used 7 publicly available microarray datasets to identify gene signatures related to recurrence in optimally debulked SOC patients, and validated their expressions in an independent clinic cohort of 127 patients using immunohistochemistry (IHC). We identified a two-gene signature including KCNN4 and S100A14 which was related to recurrence in optimally debulked SOC patients. Their mRNA expression levels were positively correlated and regulated by DNA copy number alterations (CNA) (KCNN4: p=1.918e-05) and DNA promotermethylation (KCNN4: p=0.0179; S100A14: p=2.787e-13). Recurrence prediction models built in the TCGA dataset based on KCNN4 and S100A14 individually and in combination showed good prediction performance in the other 6 datasets (AUC:0.5442-0.9524). The independent cohort supported the expression difference between SOC recurrences. Also, a KCNN4 and S100A14-centered protein interaction subnetwork was built from the STRING database, and the shortest regulation path between them, called the KCNN4-UBA52-KLF4-S100A14 axis, was identified. This discovery might facilitate individualized treatment of SOC.

Inhibitor of Differentiation/DNA Binding 1 (ID1) Inhibits Etoposide-induced Apoptosis in a c-Jun/c-Fos-dependent Manner

ID1 (inhibitor of differentiation/DNA binding 1) acts an important role in metastasis, tumorigenesis, and maintenance of cell viability. It has been shown that the up-regulation of ID1 is correlated with poor prognosis and the resistance to chemotherapy of human cancers. However, the underlying molecular mechanism remains elusive. Here, we determined for the first time that up-regulating ID1 upon etoposide activation was mediated through AP-1 binding sites within theID1promoter and confirmed that ID1 enhanced cell resistance to DNA damage-induced apoptosis in esophageal squamous cell carcinoma cells. Ablation of c-Jun/c-Fos or ID1 expression enhanced etoposide-mediated apoptosis through increasing activity of caspase 3 and PARP cleavage. Moreover, c-Jun/c-Fos and ID1 were positively correlated in human cancers. More importantly, simultaneous high expression of ID1 and c-Jun or c-Fos was correlated with poor survival in cancer patients. Collectively, we demonstrate the importance of c-Jun/c-Fos-ID1 signaling pathway in chemoresistance of esophageal cancer cells and provide considerable insight into understanding the underlying molecular mechanisms in esophageal squamous cell carcinoma cell biology.

Interplay between arginine methylation and ubiquitylation regulates KLF4-mediated genome stability and carcinogenesis

KLF4 is an important regulator of cell-fate decision, including DNA damage response and apoptosis. We identify a novel interplay between protein modifications in regulating KLF4 function. Here we show that arginine methylation of KLF4 by PRMT5 inhibits KLF4 ubiquitylation by VHL and thereby reduces KLF4 turnover, resulting in the elevation of KLF4 protein levels concomitant with increased transcription of KLF4-dependent p21 and reduced expression of KLF4-repressed Bax. Structure-based modelling and simulations provide insight into the molecular mechanisms of KLF4 recognition and catalysis by PRMT5. Following genotoxic stress, disruption of PRMT5-mediated KLF4 methylation leads to abrogation of KLF4 accumulation, which, in turn, attenuates cell cycle arrest. Mutating KLF4 methylation sites suppresses breast tumour initiation and progression, and immunohistochemical stain shows increased levels of both KLF4 and PRMT5 in breast cancer tissues. Taken together, our results point to a critical role for aberrant KLF4 regulation by PRMT5 in genome stability and breast carcinogenesis.

Krüppel-like factor 4 plays an important role in regulating responses to DNA damage, cell-fate decision and apoptosis. Here the authors show that aberrant regulation by methyltransferase PRMT5 results in failure to arrest the cell cycle and genome instability, pointing to a role in carcinogenesis.

12-O-Tetradecanoylphorbol-13-Acetate Induces Up-Regulated Transcription of Variant 1 but Not Variant 2 of VIL2 in Esophageal Squamous Cell Carcinoma Cells via ERK1/2/AP-1/Sp1 Signaling

The membrane-cytoskeleton link organizer ezrin may be the most "dramatic" tumor marker, being strongly over-expressed in nearly one-third of human malignancies. However, the molecular mechanisms of aberrant ezrin expression still need to be clarified. Ezrin, encoded by the VIL2 gene, has two transcript variants that differ in the transcriptional start site (TSS): V1 and V2. Both V1 and V2 encode the same protein. Here, we found that 12-O-tetradecanoylphorbol-13-acetate (TPA) induced over-expression of human VIL2 in esophageal squamous cell carcinoma (ESCC) cells. Furthermore, VIL2 V1 but not V2 was up-regulated after TPA stimulation in a time-dependent manner. AP-1 and Sp1 binding sites within the promoter region of VIL2 V1 acted not only as basal transcriptional elements but also as a composite TPA-responsive element (TRE) for the transcription of VIL2 V1. TPA stimulation enhanced c-Jun and Sp1 binding to the TRE via activation of the ERK1/2 pathway and increased protein levels of c-Jun, c-Fos, and Sp1, resulting in over-expression of VIL2 V1, whereas the MEK1/2 inhibitor U0126 blocked these events. Finally, we showed that TPA promoted the migration of ESCC cells whereas MEK1/2 inhibitor or ezrin silencing could partially inverse this alteration. Taken together, these results suggest that TPA is able to induce VIL2 V1 over-expression in ESCC cells by activating MEK/ERK1/2 signaling and increasing binding of Sp1 and c-Jun to the TRE of the VIL2 V1 promoter, and that VIL2 is an important TPA-induced effector.

Krüppel-like Factor 4 Promotes Esophageal Squamous Cell Carcinoma Differentiation by Up-regulating Keratin 13 Expression

Squamous cell differentiation requires the coordinated activation and repression of genes specific to the differentiation process; disruption of this program accompanies malignant transformation of epithelium. The exploration of genes that control epidermal proliferation and terminal differentiation is vital to better understand esophageal carcinogenesis. KLF4 is a member of the KLF family of transcription factors and is involved in both cellular proliferation and differentiation. This study using immunohistochemistry analysis of KLF4 in clinical specimens of esophageal squamous cell carcinoma (ESCC) demonstrated that decreased KLF4 was substantially associated with poor differentiation. Moreover, we determined that both KLF4 and KRT13 levels were undoubtedly augmented upon sodium butyrate-induced ESCC differentiation and G1 phase arrest. Conversely, silencing of KLF4 and KRT13 abrogated the inhibition of G1-S transition induced by sodium butyrate. Molecular investigation demonstrated that KLF4 transcriptionally regulated KRT13 and the expression of the two molecules appreciably correlated in ESCC tissues and cell lines. Collectively, these results suggest that KLF4 transcriptionally regulates KRT13 and is invovled in ESCC cell differentiation.

Downregulation of 425G>a variant of calcium-binding protein S100A14 associated with poor differentiation and prognosis in gastric cancer

PURPOSE

Altered level of S100 calcium-binding proteins is involved in tumor development and progression. However, their role in gastric cancer (GC) is not well documented. We investigated the expression pattern of S100 proteins and differentiation or prognosis as well as possible mechanisms in GC.

METHODS

RT-PCR, Western blot analysis, and immunohistochemistry were used to determine the mRNA and protein expression of S100 family genes in GC. The polymorphisms of promoter and 5'-UTR of S100A14 gene were identified and related to luciferase reporter gene activity. Association of S100A14 expression with clinicopathologic features and survival in GC was analyzed.

RESULTS

We detected upregulated S100A2, S100A6, S100A10, and S100A11 expression and downregulated S100P and S100B expression in GC. Particularly, we detected differential mRNA and protein expression of S100A14 in GC cell lines and primary tumors. Furthermore, S100A14 expression change was related to a differentiated GC phenotype, with an expression in 31/40 (77.5 %) samples of well-differentiated tumors and 29/85 (34.1 %) samples of poorly differentiated tumors (P < 0.001). Moreover, 5-year survival was better in GC cases with positive than negative S100A14 level (P = 0.02). The genetic variant 425G>A on the 5'-UTR of S100A14 was associated with reduced S100A14 expression in GC cells.

CONCLUSION

Decreased expression of S100A14 with presence of its genetic variant 425G>A may be associated with an undifferentiated phenotype and poor prognosis in GC.

S100A14, a mediator of epithelial-mesenchymal transition, regulates proliferation, migration and invasion of human cervical cancer cells

S100A14 is an EF-hand calcium-binding protein that has been reported to exert its biological effects on different types of cells. However, the potential clinical significance and biological functions of S100A14 in cervical cancer has not yet been clarified. In this study, we firstly examined the correlation between S100A14 expression and clinical-pathological parameters in cervical cancers. Next, we observed the effect of S100A14 on cell cycle progression, cell proliferation, migration and invasion by employing lentiviral-mediated overexpression and knockdown of S100A14 in cervical cancer cells. Furthermore, we investigated the underlying mechanism of S100A14 affecting cell migration and invasion. Immunohistochemistry analysis demonstrated that S100A14 expression was associated with the International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.025) and lymph node (LN) metastasis (P = 0.001). Functional assays showed that S100A14 overexpression increased the proportion of G2/M phase, promoted cell proliferation, migration, and invasion, whereas S100A14 knockdown exhibited adverse effect on above properties. Mechanistic investigation demonstrated that S100A14 can act as a mediator of epithelial-mesenchymal transition (EMT). And overexpression of S100A14 increased expression of N-cadherin and Vimentin while decreased expression of E-cadherin. The opposite results were observed in S100A14-silenced cells. Taken together, our data indicate that S100A14 has a crucial role in cervical cancer progression. This study significantly increases our understanding of S100A14 functional roles in cervical cancer, which may lead to the development of a novel therapeutic target for cervical cancer.