Gene Summary

Gene:FOS; Fos proto-oncogene, AP-1 transcription factor subunit
Aliases: p55, AP-1, C-FOS
Summary:The Fos gene family consists of 4 members: FOS, FOSB, FOSL1, and FOSL2. These genes encode leucine zipper proteins that can dimerize with proteins of the JUN family, thereby forming the transcription factor complex AP-1. As such, the FOS proteins have been implicated as regulators of cell proliferation, differentiation, and transformation. In some cases, expression of the FOS gene has also been associated with apoptotic cell death. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:proto-oncogene c-Fos
Source:NCBIAccessed: 11 March, 2017


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Latest Publications: FOS (cancer-related)

Sun X, Deng Q, Liang Z, et al.
Cigarette smoke extract induces epithelial-mesenchymal transition of human bladder cancer T24 cells through activation of ERK1/2 pathway.
Biomed Pharmacother. 2017; 86:457-465 [PubMed] Related Publications
Bladder cancer is a common genitourinary malignant disease worldwide. Abundant evidence has shown that cigarette smoke (CS) is a crucial risk factor for bladder cancer. Nevertheless, the mechanism underlying the relationship between cigarette smoking and bladder cancer remains unclear. In the present study, we investigated the effects of cigarette smoke extract (CSE) on mitogen-activated protein kinase (MAPK) pathway activation and EMT alterations in human bladder cancer T24 cells, and the preventive effect of extracellular regulated protein kinases 1 and 2 (ERK1/2) inhibitor U0126 was further examined. Our results illustrated that CSE exposure induced morphological change of human bladder cancer T24 cells, enhanced migratory and invasive capacities, reduced epithelial marker expression and elevated mesenchymal marker expression. Meanwhile, exposure of T24 cells to CSE resulted in activation of ERK1/2 pathway as well as activator protein 1 (AP-1) proteins. Interestingly, treatment with ERK1/2 inhibitor U0126 effectively abrogated CSE-triggered EMT and ERK1/2/AP-1 activation. These findings provide novel insight into the molecular mechanisms of CS-associated bladder cancer and may open up new avenues in the search for potential target of bladder cancer intervention.

Zhu L, Shen Y, Sun W
Paraoxonase 3 promotes cell proliferation and metastasis by PI3K/Akt in oral squamous cell carcinoma.
Biomed Pharmacother. 2017; 85:712-717 [PubMed] Related Publications
Paraoxonase 3 (PON3) is an oncogene in cancer, however, little is known about the mechanisms and roles of PON3 in oral squamous cell carcinoma (OSCC), which is the aim of our study. We found that the expression of PON3 was up-regulated in OSCC samples and cell lines. PON3 was associated with accelerating cell proliferation, cell cycle, migration and invasion in OSCC cells. Further research showed that PON3 was regulated by PI3K/Akt pathway. We also found that AP-1 was an important transcriptional factor regulating PON3 expression in OSCC. The study elucidates that PI3K/Akt pathway up-regulated the expression of PON3 in OSCC by AP-1.

Ahmad HM, Muiwo P, Muthuswami R, Bhattacharya A
FosB regulates expression of miR-22 during PMA induced differentiation of K562 cells to megakaryocytes.
Biochimie. 2017; 133:1-6 [PubMed] Related Publications
Expression of many miRNAs is altered in different cancers and these changes are thought to play a key role in formation and progression of cancer. In chronic myelogenous leukemia (CML) a number of miRNAs are known to be down regulated as compared to normal cells. In this report we have investigated the mechanism of this down regulation by using PMA induced differentiation of CML cell line K562 to megakaryocytes as an experimental system. On treatment with PMA, expression of many down regulated miRNAs including miR-22 is induced. PMA also induces expression of several transcription factors, including FosB, EGR1 and EGR2. Our results using a number of approaches, such as promoter reporter assay, FosB knock down and Chip assay, suggest that the expression of miR-22 is regulated transcriptionally by FosB.

Chang CD, Lin PY, Hsu JL, Shih WL
Ursolic Acid Suppresses Hepatitis B Virus X Protein-mediated Autophagy and Chemotherapeutic Drug Resistance.
Anticancer Res. 2016; 36(10):5097-5107 [PubMed] Related Publications
Hepatitis B virus X (HBx) protein is a multifunctional oncoprotein that affects diverse cell activities via regulation of various host cell signaling pathways. The current investigation demonstrated that ursolic acid (UA), a pentacyclic triterpenoid, protected hepatoma cells and reduced HBx-mediated autophagy through modulation of Ras homolog gene family member A (RhoA). Low-level ectopic HBx expression in Huh7 cells induced more significant autophagosome formation than high-level HBx expression. HBx activated beclin-1 promoter and enhanced the beclin-1 protein expression under low HBx expression. Transcription factor AP-1 played an essential function in HBx-mediated beclin-1 promoter activation. Inhibition of RhoA and its downstream effector Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) alleviated HBx-mediated autophagy significantly. Transiently-expressed HBx elicited an increased RhoA-GTP level, as well as phospho-ROCK1 transient accumulation. Utilization of transactivation-deficient HBx demonstrated that the transactivation activity of HBx is required for autophagy induction. Furthermore, UA suppressed HBx-mediated RhoA activation, beclin-1 promoter activation and subsequent autophagy induction, while, most importantly, reversed HBx-induced anti-cancer drug resistance.

Vesely DL
Heart Peptide Hormones: Adjunct and Primary Treatments of Cancer.
Anticancer Res. 2016; 36(11):5693-5700 [PubMed] Related Publications
Four heart hormones, namely atrial natriuretic peptide (ANP), long-acting natriuretic peptide (LANP), vessel dilator and kaliuretic peptide reduce up to 97% of cancer cells in vitro. These four cardiac hormones eliminate up to 80% of human pancreatic adenocarcinomas, two-thirds of human breast carcinomas and up to 86% of human small-cell lung carcinomas growing in athymic mice. ANP given intravenously for 3 hours after 'curative' lung surgery as an adjunct to surgery results in a 2-year relapse-free survival of 91% compared to 75% for those treated with surgery alone. The anticancer mechanisms of action of these peptides involve binding to receptors on the cancer cells, followed by 95% inhibition of the conversion of inactive to active rat sarcoma-bound guanosine triphosphate (RAS)-mitogen-activated protein kinase (MAPK) kinases 1/2 (MEK 1/2) (98% inhibition)-extracellular signal-related kinases 1/2 (ERK1/2) (96% inhibition) cascade in cancer cells. They are dual inhibitors of vascular endothelial growth factor (VEGF) and its VEGF2 receptor (up to 89%). They also inhibit MAPK9, i.e. c-JUN-N-terminal kinase 2. One of the downstream targets of VEGF is β-catenin, which these peptides inhibit by up to 88%. These four peptide hormones inhibit the Wingless-related integration site (WNT) pathway 68% and WNT secreted-Frizzled protein is reduced by up to 84%. Signal transducer and activator of transcription 3 (STAT3), a final 'switch' that activates gene expression that leads to malignancy, is specifically reduced up to 88% by these peptides but they do not affect STAT1. There is crosstalk between the RAS-MEK 1/2-ERK 1/2 kinase cascade, VEGF, β-catenin, JNK, WNT, and STAT pathways and each of these pathways and their crosstalk is inhibited by these peptide hormones. They enter the nucleus of cancer cells where they inhibit the proto-oncogenes c-FOS (by up to 82%) and c-JUN (by up to 61%).
CONCLUSION: These multiple kinase inhibitors have both adjunct and primary anticancer effects.

Song L, Du A, Xiong Y, et al.
γ-Aminobutyric acid inhibits the proliferation and increases oxaliplatin sensitivity in human colon cancer cells.
Tumour Biol. 2016; 37(11):14885-14894 [PubMed] Related Publications
γ-Aminobutyric acid (GABA) is a natural non-protein amino acid, which broadly exists in many plant parts and is widely used as an ingredient in the food industry. In mammals, it is widely distributed in central nervous system and non-neural tissues. In addition to a primary inhibitory neurotransmitter in the central nervous system, endogenous GABA content has been found to be elevated in neoplastic tissues in colon cancer. However, the effect of extraneous GABA on colon cancer has rarely been reported. In this study, we found the inhibitory effects of GABA on the proliferation of colon cancer cells (CCCs). The amino acid also suppressed metastasis of SW480 and SW620 cells. To further study the correlated mechanism, we analyzed the changes in cell cycle distribution and found that GABA suppressed cell cycle progression through G2/M or G1/S phase. Furthermore, RNA sequencing analysis revealed GABA-induced changes in the mRNA expression of 30 genes, including EGR1, MAPK4, NR4A1, Fos, and FosB, in all the three types of CCC. Importantly, GABA enhanced the anti-tumor efficacy of oxaliplatin (OXA) in subcutaneous xenograft tumor model in nude mice. The data suggest that GABA inhibits colon cancer cell proliferation perhaps by attenuating EGR1-NR4A1 axis, EGR1-Fos axis, and by disrupting MEK-EGR1 signaling pathway. This work reveals the pharmacological value of GABA derived from food and suggests that exogenous GABA might play an auxiliary role in polychemotherapy of colon cancer.

Hegde SM, Kumar MN, Kavya K, et al.
Interplay of nuclear receptors (ER, PR, and GR) and their steroid hormones in MCF-7 cells.
Mol Cell Biochem. 2016; 422(1-2):109-120 [PubMed] Related Publications
Steroid hormones and their nuclear receptors play a major role in the development and progression of breast cancer. MCF-7 cells are triple-positive breast cancer cells expressing estrogen receptor (ER), progesterone receptor (PR), and glucocorticoid receptor (GR). However, interaction and their role in expression pattern of activator protein (AP-1) transcription factors (TFs) are not completely understood. Hence, in our study, MCF-7 cells were used as an in vitro model system to study the interplay between the receptors and hormones. MCF-7 cells were treated with estradiol-17β (E2), progesterone (P4), and dexamethasone (Dex), alone or in combination, to study the proliferation of cells and expression of AP-1 genes. MTT assay results show that E2 or P4 induced the cell proliferation by more than 35 %, and Dex decreased the proliferation by 26 %. E2 and P4 are found to increase ERα by more than twofold and c-Jun, c-Fos, and Fra-1 AP-1 TFs by more than 1.7-fold, while Dex shows opposite effect of E2- or P4-induced effect as well as effect on the expression of nuclear receptors and AP-1 factors. E2 antagonist Fulvestrant (ICI 182,780) found to reduce proliferation and E2-induced expression of AP1-TFs, while P4 or Dex antagonist Mifepristone (RU486) is found to block GR-mediated expression of NRs and AP-1 mRNAs. Results suggest that E2 and P4 act synergistically, and Dex acts as an antagonist of E2 and P4.

Wang S, Xu X, Xu F, et al.
Combined Expression of c-jun, c-fos, and p53 Improves Estimation of Prognosis in Oral Squamous Cell Carcinoma.
Cancer Invest. 2016; 34(8):393-400 [PubMed] Related Publications
To identify the prognostic value of c-jun, c-fos, and p53 in oral cancer, we examined the impact of immunohistochemical expression of these markers on tumor progression in 157 oral squamous cell carcinoma (OSCC). We found that c-jun or c-fos was significantly associated with lymph node metastasis, and coexpression of c-jun/c-fos, or c-jun/c-fos/p53 were significantly associated with lymph node metastasis, poor differentiation and clinical stage. The coexpression of c-jun/c-fos/p53 was identified as independent prognostic factors for overall survival. Simultaneous coexpression of these markers in OSCCs might prove to be a useful indicator for differentiation of low and high-risk patients.

Deng Y, Wang Z, Zhang F, et al.
A Blockade of IGF Signaling Sensitizes Human Ovarian Cancer Cells to the Anthelmintic Niclosamide-Induced Anti-Proliferative and Anticancer Activities.
Cell Physiol Biochem. 2016; 39(3):871-88 [PubMed] Related Publications
BACKGROUND/AIMS: Ovarian cancer is the most lethal gynecologic malignancy, and there is an unmet clinical need to develop new therapies. Although showing promising anticancer activity, Niclosamide may not be used as a monotherapy. We seek to investigate whether inhibiting IGF signaling potentiates Niclosamide's anticancer efficacy in human ovarian cancer cells.
METHODS: Cell proliferation and migration are assessed. Cell cycle progression and apoptosis are analyzed by flow cytometry. Inhibition of IGF signaling is accomplished by adenovirus-mediated expression of siRNAs targeting IGF-1R. Cancer-associated pathways are assessed using pathway-specific reporters. Subcutaneous xenograft model is used to determine anticancer activity.
RESULTS: We find that Niclosamide is highly effective on inhibiting cell proliferation, cell migration, and cell cycle progression, and inducing apoptosis in human ovarian cancer cells, possibly by targeting multiple signaling pathways involved in ELK1/SRF, AP-1, MYC/MAX and NFkB. Silencing IGF-1R exert a similar but weaker effect than that of Niclosamide's. However, silencing IGF-1R significantly sensitizes ovarian cancer cells to Niclosamide-induced anti-proliferative and anticancer activities both in vitro and in vivo.
CONCLUSION: Niclosamide as a repurposed anticancer agent may be more efficacious when combined with agents that target other signaling pathways such as IGF signaling in the treatment of human cancers including ovarian cancer.

Mashimo M, Yurie Y, Kawashima K, Fujii T
CRAC channels are required for [Ca(2+)]i oscillations and c-fos gene expression after muscarinic acetylcholine receptor activation in leukemic T cells.
Life Sci. 2016; 161:45-50 [PubMed] Related Publications
AIMS: T lymphocytes express muscarinic acetylcholine receptors (mAChRs) involved in regulating their proliferation, differentiation and cytokine release. Activation of M1, M3 or M5 mAChRs increases the intracellular Ca(2+) concentration ([Ca(2+)]i) through inositol-1,4,5-phosphate (IP3)-mediated Ca(2+) release from endoplasmic reticulum Ca(2+) stores. In addition, T lymphocytes express Ca(2+)-release activated Ca(2+) (CRAC) channels to induce Ca(2+) influx and to regulate diverse immune functions. Our aim in the present study was to assess the role of CRAC channels during mAChR activation in the Ca(2+)-dependent transduction that contributes to the regulation of T cell function.
MAIN METHODS: Changes in [Ca(2+)]i following mAChR activation on human leukemic T cells, CCRF-CEM (CEM), were monitored using fura-2, based on the ratio of 510nm fluorescences elicited by excitation at 340nm and 380nm (R340/380).
KEY FINDINGS: We demonstrate that CEM cells express mainly M3 and M5 mAChRs, but little the M1 subtype, and that oxotremorine-M (Oxo-M), an mAChR agonist, induces an initial transient increase in [Ca(2+)]i followed by repetitive [Ca(2+)]i oscillations. Removing extracellular Ca(2+) or pharmacological blockade of CRAC channels abolished the [Ca(2+)]i oscillations without affecting the initial [Ca(2+)]i transient induced by Oxo-M. Moreover, CRAC channel blockade also suppressed Oxo-M-induced c-fos and interleukin-2 expression.
SIGNIFICANCE: These results suggest that upon M3 or M5 mAChR activation, IP3-mediated Ca(2+) release induces extracellular Ca(2+) influx through CRAC channels, which generates repetitive [Ca(2+)]i oscillations and, in turn, enhances c-fos gene expression in T lymphocytes.

Friedrich T, Söhn M, Gutting T, et al.
Subcellular compartmentalization of docking protein-1 contributes to progression in colorectal cancer.
EBioMedicine. 2016; 8:159-72 [PubMed] Free Access to Full Article Related Publications
Full-length (FL) docking protein-1 (DOK1) is an adapter protein which inhibits growth factor and immune response pathways in normal tissues, but is frequently lost in human cancers. Small DOK1 variants remain in cells of solid tumors and leukemias, albeit, their functions are elusive. To assess the so far unknown role of DOK1 in colorectal cancer (CRC), we generated DOK1 mutants which mimic the domain structure and subcellular distribution of DOK1 protein variants in leukemia patients. We found that cytoplasmic DOK1 activated peroxisome-proliferator-activated-receptor-gamma (PPARγ) resulting in inhibition of the c-FOS promoter and cell proliferation, whereas nuclear DOK1 was inactive. PPARγ-agonist increased expression of endogenous DOK1 and interaction with PPARγ. Forward translation of this cell-based signaling model predicted compartmentalization of DOK1 in patients. In a large series of CRC patients, loss of DOK1 protein was associated with poor prognosis at early tumor stages (*p=0.001; n=1492). In tumors with cytoplasmic expression of DOK1, survival was improved, whereas nuclear localization of DOK1 correlated with poor outcome, indicating that compartmentalization of DOK1 is critical for CRC progression. Thus, DOK1 was identified as a prognostic factor for non-metastatic CRC, and, via its drugability by PPARγ-agonist, may constitute a potential target for future cancer treatments.

Sheikh A, Takatori A, Hossain MS, et al.
Unfavorable neuroblastoma prognostic factor NLRR2 inhibits cell differentiation by transcriptional induction through JNK pathway.
Cancer Sci. 2016; 107(9):1223-32 [PubMed] Free Access to Full Article Related Publications
The novel human gene family encoding neuronal leucine rich repeat (NLRR) proteins were identified as prognostic markers from our previous screening of primary neuroblastoma (NB) cDNA libraries. Of the NLRR gene family members, NLRR1 and NLRR3 are associated with the regulation of cellular proliferation and differentiation, respectively. However, the functional regulation and clinical significance of NLRR2 in NB remain unclear. Here, we evaluated the differential expression of NLRR2, where high expressions of NLRR2 were significantly associated with a poor prognosis of NB (P = 0.0009), in 78 NBs. Enforced expression of NLRR2 in NB cells enhanced cellular proliferation and induced resistance to retinoic acid (RA)-mediated cell growth inhibition. In contrast, knockdown of NLRR2 exhibited growth inhibition effects and enhanced RA-induced cell differentiation in NB cells. After RA treatment, NLRR2 expression was increased and correlated with the upregulation of c-Jun, a member of the activator protein-1 (AP-1) family in NB cells. Moreover, the expressions of NLRR2 and c-Jun were suppressed by treatment with a JNK inhibitor, which ameliorated the promoter activity of the NLRR2 gene while knockdown of c-Jun reduced NLRR2 expression. We then searched AP-1 binding consensus in the NLRR2 promoter region and confirmed c-Jun recruitment at a consensus. Conclusively, NLRR2 must be an inducible gene regulated by the JNK pathway to enhance cell survival and inhibit NB cell differentiation. Therefore, NLRR2 should have an important role in NB aggressiveness and be a potential therapeutic target for the treatment of RA resistant and aggressive NB.

Elkady AI, Hussein RA, El-Assouli SM
Harmal Extract Induces Apoptosis of HCT116 Human Colon Cancer Cells, Mediated by Inhibition of Nuclear Factor-κB and Activator Protein-1 Signaling Pathways and Induction of Cytoprotective Genes.
Asian Pac J Cancer Prev. 2016; 17(4):1947-59 [PubMed] Related Publications
BACKGROUND: Colorectal cancer (CRC) is a major cause of morbidity and mortality, being the second most common type of cancer worldwide in both men and women. It accounts yearly for approximately 9% of all new cases of cancers. Furthermore, the current chemotherapeutic regimens seem unsatisfactory, so that exploration of novel therapeutic modalities is needed. The present study was undertaken to investigate the inhibitory effects of a crude alkaloid extract (CAERS) of a medicinal herb, Rhazya stricta, on proliferation of CRC HCT116 cells and to elucidate mechanisms of action. To achieve these aims, we utilized MTT, comet, DNA laddering and gene reporter assays, along with Western blot and RT-PCR analyses.
RESULTS: We found that CAERS inhibited cell proliferation and induced apoptotic cell death in HCT116 cells. Hallmarks of morphological and biochemical signs of apoptosis were clearly evident. CAERS down-regulated DNA-binding and transcriptional activities of NF-κB and AP-1 proteins, while up-regulating expression of the Nrf-2 protein. It also down-regulated expression levels of the ERK MAPK, Bcl-2, cyclin D1, CDK-4, survivin and VEGF and up-regulated levels of Bax, caspase-3/7 and -9, p53, p21, Nrf-2. Markedly, it promoted mRNA expression levels of cytoprotective genes including the hemeoxygenase-1, NAD(P)H quinine oxidoreductase 1 and UDP-glucuronyltransferase.
CONCLUSIONS: These findings indicate that CAERS exerts antiproliferative action on CRC cells through induction of apoptotic mechanisms, and suggest CAERS could be a promising agent for studying and developing novel chemotherapeutic agents aimed at novel molecular targets for the treatment of CRC.

Lau EY, Lo J, Cheng BY, et al.
Cancer-Associated Fibroblasts Regulate Tumor-Initiating Cell Plasticity in Hepatocellular Carcinoma through c-Met/FRA1/HEY1 Signaling.
Cell Rep. 2016; 15(6):1175-89 [PubMed] Related Publications
Like normal stem cells, tumor-initiating cells (T-ICs) are regulated extrinsically within the tumor microenvironment. Because HCC develops primarily in the context of cirrhosis, in which there is an enrichment of activated fibroblasts, we hypothesized that cancer-associated fibroblasts (CAFs) would regulate liver T-ICs. We found that the presence of α-SMA(+) CAFs correlates with poor clinical outcome. CAF-derived HGF regulates liver T-ICs via activation of FRA1 in an Erk1,2-dependent manner. Further functional analysis identifies HEY1 as a direct downstream effector of FRA1. Using the STAM NASH-HCC mouse model, we find that HGF-induced FRA1 activation is associated with the fibrosis-dependent development of HCC. Thus, targeting the CAF-derived, HGF-mediated c-Met/FRA1/HEY1 cascade may be a therapeutic strategy for the treatment of HCC.

Chen YJ, Lin KN, Jhang LM, et al.
Gallic acid abolishes the EGFR/Src/Akt/Erk-mediated expression of matrix metalloproteinase-9 in MCF-7 breast cancer cells.
Chem Biol Interact. 2016; 252:131-40 [PubMed] Related Publications
Several studies have revealed that natural compounds are valuable resources to develop novel agents against dysregulation of the EGF/EGFR-mediated matrix metalloproteinase-9 (MMP-9) expression in cancer cells. In view of the findings that EGF/EGFR-mediated MMP-9 expression is closely related to invasion and metastasis of breast cancer. To determine the beneficial effects of gallic acid on the suppression of breast cancer metastasis, we explored the effect of gallic acid on MMP-9 expression in EGF-treated MCF-7 breast cancer cells. Treatment with EGF up-regulated MMP-9 mRNA and protein levels in MCF-7 cells. EGF treatment induced phosphorylation of EGFR and elicited Src activation, subsequently promoting Akt/NFκB (p65) and ERK/c-Jun phosphorylation in MCF-7 cells. Activation of Akt/p65 and ERK/c-Jun was responsible for the MMP-9 up-regulation in EGF-treated cells. Gallic acid repressed the EGF-induced activation of EGFR and Src; furthermore, inactivation of Akt/p65 and ERK/c-Jun was a result of the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. Over-expression of constitutively active Akt and MEK1 or over-expression of constitutively active Src eradicated the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. A chromosome conformation capture assay showed that EGF induced a chromosomal loop formation in the MMP-9 promoter via NFκB/p65 and AP-1/c-Jun activation. Treatment with gallic acid, EGFR inhibitor, or Src inhibitor reduced DNA looping. Taken together, our data suggest that gallic acid inhibits the activation of EGFR/Src-mediated Akt and ERK, leading to reduced levels of p65/c-Jun-mediated DNA looping and thus inhibiting MMP-9 expression in EGF-treated MCF-7 cells.

Qiu Q, Jiang J, Lin L, et al.
Downregulation of RSK2 influences the biological activities of human osteosarcoma cells through inactivating AKT/mTOR signaling pathways.
Int J Oncol. 2016; 48(6):2508-20 [PubMed] Related Publications
RSK2 (90 kDa ribosomal S6 kinase) is a downstream effector of the Ras/ERK (extracellular signal-regulated kinase) signaling pathway that has major functions in cell biological activities, including regulating nuclear signaling, cell cycle progression, cell proliferation, cell growth, protein synthesis, cell migration and cell survival, and is expressed in most types of human malignant tumors, including lung cancer, prostate and breast tumors, skin cancer and osteosarcomas (OS). RSK2 was found to be essential for osteosarcoma formation. To investigate whether RSK2 is expressed at high levels in human osteosarcome tissues and whether its expression is correlated with the aggressive biological behavior of osteosarcoma cell line (OCLs), we assessed the association between RSK2 expression and OS cell progression, as well as the effects of RSK2 inhibition on the biological activities of osteosarcoma cells. We performed immunohistochemistry to analyze the expression of RSK2 in specimens from 30 humans with osteosarcoma, and 15 normal tissues. RSK2 gene expression levels in 30 specimens with osteosarcoma were significantly higher than those of normal tissues. We performed RNA interference on three OCLs to evaluate cell apoptosis, cell growth, cell proliferation, cell motility, chemosensitivity and oncogenicity. After transfection with RSK2 shRNA, increased cell apoptosis, cell growth inhibition, cell cycle progression, weaker cell proliferation, cell migration and weaker tumor formation were observed in all OCLs. These results suggested that RSK2 expression may mediate the biological activities of OS cells and RSK2 may be an effective therapeutic target for the treatment of osteosarcomas. The AKT/mTOR, MAPK/ERK/c-Fos and Bcl2/Bax pathways were analysed to clarify the mechanisms involved.

Ahn SH, Park H, Ahn YH, et al.
Necrotic cells influence migration and invasion of glioblastoma via NF-κB/AP-1-mediated IL-8 regulation.
Sci Rep. 2016; 6:24552 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme (GBM) is the most common primary intracranial tumor in adults and has poor prognosis. Diffuse infiltration into normal brain parenchyma, rapid growth, and the presence of necrosis are remarkable hallmarks of GBM. However, the effect of necrotic cells on GBM growth and metastasis is poorly understood at present. In this study, we examined the biological significance of necrotic tissues by exploring the molecular mechanisms underlying the signaling network between necrotic tissues and GBM cells. The migration and invasion of the GBM cell line CRT-MG was significantly enhanced by treatment with necrotic cells, as shown by assays for scratch wound healing and spheroid invasion. Incubation with necrotic cells induced IL-8 secretion in CRT-MG cells in a dose-dependent manner. In human GBM tissues, IL-8 positive cells were mainly distributed in the perinecrotic region, as seen in immunohistochemistry and immunofluorescence analysis. Necrotic cells induced NF-κB and AP-1 activation and their binding to the IL-8 promoter, leading to enhanced IL-8 production and secretion in GBM cells. Our data demonstrate that when GBM cells are exposed to and stimulated by necrotic cells, the migration and invasion of GBM cells are enhanced and facilitated via NF-κB/AP-1 mediated IL-8 upregulation.

Maximov VV, Aqeilan RI
Genetic factors conferring metastasis in osteosarcoma.
Future Oncol. 2016; 12(13):1623-44 [PubMed] Related Publications
Osteosarcoma (OS) is a deadly bone malignancy affecting mostly children and adolescents. OS has outstandingly complex genetic alterations likely due to p53-independent genomic instability. Based on analysis of recent published research we claim existence of various genetic mechanisms of osteosarcomagenesis conferring great variability to different OS properties including metastatic potential. We also propose a model explaining how diverse genetic mechanisms occur and providing a framework for future research. P53-independent preexisting genomic instability, which precedes and frequently causes TP53 genetic alterations, is central in our model. In addition, our analyses reveal a possible cooperation between aberrantly activated HIF-1α and AP-1 genetic pathways in OS metastasis. We also review the involvement of noncoding RNA genes in OS metastasis.

Abdel-Latif MM, Inoue H, Kelleher D, Reynolds JV
Factors regulating nuclear factor-kappa B activation in esophageal cancer cells: Role of bile acids and acid.
J Cancer Res Ther. 2016 Jan-Mar; 12(1):364-73 [PubMed] Related Publications
AIMS: Gastroesophageal reflux disease is considered to be a major risk in the development of esophageal adenocarcinoma. Nuclear factor-kappa B (NF-κB) plays important roles in the regulation of several genes coding for cytokines, cell proliferation, and apoptosis. To understand the role of bile and acid in the causation of esophageal cancer, we have examined the effects of bile acids and acid on NF-κB activation in the esophageal epithelial cells OE33 and SKGT-4 qualitatively and quantitatively.
MATERIALS AND METHODS: Analysis of NF-κB activation in esophageal epithelial cells in response to bile acids and acid was performed by electrophoretic mobility shift assay, Western blotting and the translocation NF-κB was assessed by high content analysis (HCA). Cyclooxygenase-2 (COX-2) promoter activity was assessed by transient transfection assays.
RESULTS: This study demonstrated that bile acids and acid activated NF-κB in a dose- and time-dependent manner. HCA analysis was an invaluable method in quantifying NF-κB translocation at the single cell population level following bile or acid treatment. Furthermore, deoxycholic acid (DCA) and acid-induced COX-2 promoter activity, and a mutation in the NF-κB and activator protein-1 (AP-1) binding sites remarkably reduced the reporter gene activity induced by DCA or acid.
CONCLUSIONS: Our data demonstrate that bile and acid induce NF-κB activation in esophageal cells qualitatively and quantitatively. The induction of COX-2 promoter activity by DCA and acid was mediated via NF-κB and AP-1 transcription. The activation of NF-κB signaling pathway in esophageal cells may contribute to the development of esophageal cancer, and, therefore, modulating of NF-κB pathway may uncover new therapeutic strategies.

Blonska M
ATF3, a new player in DLBCL cell survival.
Blood. 2016; 127(14):1736-7 [PubMed] Related Publications
In this issue of Blood, Juilland and colleagues reveal the expression pattern and the role of different members of the activating transcription factor (ATF) family in survival of diffuse large B-cell lymphoma (DLBCL) cells.

Jung JS, Ahn YH, Moon BI, Kim HS
Exogenous C2 Ceramide Suppresses Matrix Metalloproteinase Gene Expression by Inhibiting ROS Production and MAPK Signaling Pathways in PMA-Stimulated Human Astroglioma Cells.
Int J Mol Sci. 2016; 17(4):477 [PubMed] Free Access to Full Article Related Publications
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, which play a pivotal role in invasion, migration, and angiogenesis of glioma. Therefore, controlling MMPs is potentially an important therapeutic strategy for glioma. In the present study, we found that exogenous cell-permeable short-chain C2 ceramide inhibits phorbol myristate acetate (PMA)-induced MMP-1, -3, and -9 gene expressions in U87MG and U373MG human astroglioma cells. In addition, C2 ceramide inhibited the protein secretion and enzymatic activities of MMP-1, -3, and -9. The Matrigel invasion assay and wound healing assay showed that C2 ceramide suppresses the in vitro invasion and migration of glioma cells, which appears to be involved in strong inhibition of MMPs by C2 ceramide. Subsequent mechanistic studies revealed that C2 ceramide inhibits PMA-induced mitogen-activated protein kinase (MAPK) phosphorylation and nuclear factor (NF)-κB/activator protein (AP)-1 DNA binding activities. Furthermore, C2 ceramide significantly inhibited PMA-induced reactive oxygen species (ROS) production and NADPH oxidase 4 (NOX4) expression, and inhibition of ROS by diphenylene iodonium (DPI, NADPH oxidase inhibitor) mimicked the effects of C2 ceramide on MMP expression and NF-κB/AP-1 via inhibition of p38 MAPK. The results suggest C2 ceramide inhibits MMP expression and glioma invasion, at least partly, by modulating ROS-p38 MAPK signaling axis and other MAPK signaling pathways.

Zhang H, Liang C, Hou X, et al.
Study of the combined treatment of lung cancer using gene-loaded immunomagnetic albumin nanospheres in vitro and in vivo.
Int J Nanomedicine. 2016; 11:1039-50 [PubMed] Free Access to Full Article Related Publications
Combination therapy for lung cancer has garnered widespread attention. Radiation therapy, gene therapy, and molecular targeted therapy for lung cancer have certain effects, but the disadvantages of these treatment methods are evident. Combining these methods can decrease their side effects and increase their curative effects. In this study, we constructed a pYr-ads-8-5HRE-cfosp-iNOS-IFNG plasmid (a gene circuit that can express IFNγ), which is a gene circuit, and used that plasmid together with C225 (cetuximab) to prepare gene-loaded immunomagnetic albumin nanospheres (IMANS). Moreover, we investigated the therapeutic effects of gene-loaded IMANS in combination with radiation therapy on human lung cancer in vitro and in vivo. The results showed that this gene circuit was successively constructed and confirmed that the expression of INFγ was increased due to the gene circuit. Gene-loaded IMANS combined with radiation therapy demonstrated improved results in vitro and in vivo. In conclusion, gene-loaded IMANS enhanced the efficacy of combination therapy, solved problems related to gene transfer, and specifically targeted lung cancer cells.

López-Knowles E, Gao Q, Cheang MC, et al.
Heterogeneity in global gene expression profiles between biopsy specimens taken peri-surgically from primary ER-positive breast carcinomas.
Breast Cancer Res. 2016; 18(1):39 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Gene expression is widely used for the characterisation of breast cancers. Variability due to tissue heterogeneity or measurement error or systematic change due to peri-surgical procedures can affect measurements but is poorly documented. We studied the variability of global gene expression between core-cuts of primary ER+ breast cancers and the impact of delays to tissue stabilisation due to sample X-ray and of diagnostic core cutting.
METHODS: Twenty-six paired core-cuts were taken immediately after tumour excision and up to 90 minutes delay due to sample X-ray; 57 paired core-cuts were taken at diagnosis and 2 weeks later at surgical excision. Whole genome expression analysis was conducted on extracted RNA. Correlations and differences were assessed between the expression of individual genes, gene sets/signatures and intrinsic subtypes.
RESULTS: Twenty-three and 56 sample pairs, respectively, were suitable for analysis. The range of correlations for both sample sets were similar with the majority being >0.97 in both. Correlations between pairs for 18 commonly studied genes were also similar between the studies and mainly with Pearson correlation coefficients >0.6 except for a small number of genes, which had a narrow-dynamic range (e.g. MKI67, SNAI2). There was no systematic difference in intrinsic subtyping between the first and second sample of either set but there was c.15 % discordance between the subtype assignments between the pairs, mainly where the subtyping of individual samples was less certain. Increases in the expression of several stress/early-response genes (e.g. FOS, FOSB, JUN) were found in both studies and confirmed findings in earlier smaller studies. Increased expression of IL6, IGFBP2 and MYC (by 17 %, 14 % and 44 %, respectively) occurred between the samples taken 2 weeks apart and again confirmed findings from an earlier study.
CONCLUSIONS: There is generally good correlation in gene expression between pairs of core-cuts except where genes have a narrow dynamic range. Similar correlation coefficients to the average gene expression profiles of intrinsic subtype, particularly LumA and LumB, can lead to discordances between assigned subtypes. Substantial changes in expression of early-response genes occur within an hour after surgery and in IL6, IGFB2 and MYC as a result of diagnostic core-cut biopsy.
TRIAL REGISTRATION: Trial number CRUK/07/015 . Study start date September 2008.

Hong H, He C, Zhu S, et al.
CCR7 mediates the TNF-α-induced lymphatic metastasis of gallbladder cancer through the "ERK1/2 - AP-1" and "JNK - AP-1" pathways.
J Exp Clin Cancer Res. 2016; 35:51 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: CC-chemokine receptor 7 (CCR7), which plays an important role in cell directional movement, is highly expressed in various cancers and positively related to lymph node metastasis. The inflammatory cytokine tumour necrosis factor (TNF)-α promotes tumour progression and lymph node metastasis in gallbladder cancer (GBC). However, the expression of CCR7 in GBC is unclear, and its role in the TNF-α-induced lymphatic metastasis of GBC requires further research.
METHODS: The expression of CCR7 in clinical samples was detected by immunohistochemistry, and the relationship between CCR7 and clinicopathological factors or the TNF-α level of the bile was analyzed. After treatment with various concentrations of TNF-α, CCR7 expression in GBC cell lines was measured by Western blotting. The relative luciferase reporter assay, site-directed mutagenesis and chromatin immunoprecipitation were used to analyze the promoter activity and transcriptional regulation of CCR7. MAPKs inhibitors were used to explore the upstream signalling molecules of AP-1. We established a NOZ cell line stably expressing lentiviral CCR7 shRNA that effectively silenced the expression of CCR7, and to determine the role of TNF-α - CCR7 axis in the migration of GBC cells to the lymphatic system by transwell assays and animal experiments.
RESULTS: CCR7 was highly expressed in GBC samples. Higher expression of CCR7 was associated with American Joint Committee on Cancer (AJCC) staging and lymph node metastasis. Moreover, we found that CCR7 expression in GBC tissue was positively correlated with the levels of TNF-α in the bile, and that TNF-α enhanced the promoter activity and protein expression of CCR7 through the "ERK1/2-AP-1" and "JNK-AP-1" pathways. Finally, we revealed that TNF-α could promote GBC cell migration to lymphatic endothelial cells or lymph nodes through upregulation of CCR7 in vitro and in vivo.
CONCLUSIONS: Our study suggests that CCR7 is highly expressed in GBC, and mediates the TNF-α-induced lymphatic metastasis of GBC through the "TNF-α - ERK1/2 - AP-1 - CCR7" and "TNF-α - JNK - AP-1 - CCR7" pathways.

Hong H, Jiang L, Lin Y, et al.
TNF-alpha promotes lymphangiogenesis and lymphatic metastasis of gallbladder cancer through the ERK1/2/AP-1/VEGF-D pathway.
BMC Cancer. 2016; 16:240 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Tumor necrosis factor-alpha (TNF-α), a key player in cancer-related inflammation, was recently demonstrated to be involved in the lymphatic metastasis of gallbladder cancer (GBC). Vascular endothelial growth factor D (VEGF-D) is a key lymphangiogenic factor that is associated with lymphangiogenesis and lymph node metastasis in GBC. However, whether VEGF-D is involved in TNF-α-induced lymphatic metastasis of GBC remains undetermined.
METHODS: The expression of VEGF-D in patient specimens was detected by immunohistochemistry and the relationship between VEGF-D in the tissue and TNF-α in the bile of the matching patients was analyzed. The VEGF-D mRNA and protein levels after treatment with exogenous TNF-α in NOZ, GBC-SD and SGC-996 cell lines were measured by real-time PCR and ELISA. The promoter activity and transcriptional regulation of VEGF-D were analyzed with the relative luciferase reporter assay, mutant constructs, electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP) assay, RNA interference and Western blotting. Inhibitors of JNK, p38 MAPK and ERK1/2 were used to explore the upstream signaling effector of AP-1. We used lentiviral vector expressing a VEGF-D shRNA construct to knockdown VEGF-D gene in NOZ and GBC-SD cells. The role of the TNF-α-VEGF-D axis in the tube formation of human dermal lymphatic endothelial cells (HDLECs) was determined using a three-dimensional coculture system. The role of the TNF-α - VEGF-D axis in lymphangiogenesis and lymph node metastasis was studied via animal experiment.
RESULTS: TNF-α levels in the bile of GBC patients were positively correlated with VEGF-D expression in the clinical specimens. TNF-α can upregulate the protein expression and promoter activity of VEGF-D through the ERK1/2 - AP-1 pathway. Moreover, TNF-α can promote tube formation of HDLECs, lymphangiogenesis and lymph node metastasis of GBC by upregulation of VEGF-D in vitro and in vivo.
CONCLUSION: Taken together, our data suggest that TNF-α can promote lymphangiogenesis and lymphatic metastasis of GBC through the ERK1/2/AP-1/VEGF-D pathway.

Zhu P, Aliabadi HM, Uludağ H, Han J
Identification of Potential Drug Targets in Cancer Signaling Pathways using Stochastic Logical Models.
Sci Rep. 2016; 6:23078 [PubMed] Free Access to Full Article Related Publications
The investigation of vulnerable components in a signaling pathway can contribute to development of drug therapy addressing aberrations in that pathway. Here, an original signaling pathway is derived from the published literature on breast cancer models. New stochastic logical models are then developed to analyze the vulnerability of the components in multiple signalling sub-pathways involved in this signaling cascade. The computational results are consistent with the experimental results, where the selected proteins were silenced using specific siRNAs and the viability of the cells were analyzed 72 hours after silencing. The genes elF4E and NFkB are found to have nearly no effect on the relative cell viability and the genes JAK2, Stat3, S6K, JUN, FOS, Myc, and Mcl1 are effective candidates to influence the relative cell growth. The vulnerabilities of some targets such as Myc and S6K are found to vary significantly depending on the weights of the sub-pathways; this will be indicative of the chosen target to require customization for therapy. When these targets are utilized, the response of breast cancers from different patients will be highly variable because of the known heterogeneities in signaling pathways among the patients. The targets whose vulnerabilities are invariably high might be more universally acceptable targets.

Cheng F, Su L, Yao C, et al.
SIRT1 promotes epithelial-mesenchymal transition and metastasis in colorectal cancer by regulating Fra-1 expression.
Cancer Lett. 2016; 375(2):274-83 [PubMed] Related Publications
Understanding molecular mechanisms of colorectal cancer (CRC) metastasis is urgently required for targeted therapy and prognosis of metastatic CRC. In this study, we explored potential effects of silent mating type information regulation 2 homolog 1 (SIRT1) on CRC metastasis. Our data showed that ectopic expression of SIRT1 markedly increased the migration and invasion of CRC cells. In contrast, silencing SIRT1 repressed this behavior in aggressive CRC cells. Tumor xenograft experiments revealed that knockdown of SIRT1 impaired CRC metastasis in vivo. Silencing SIRT1 in CRC cells induced mesenchymal-epithelial transition (MET), which is the reverse process of epithelial-mesenchymal transition (EMT) and characterized by a gain of epithelial and loss of mesenchymal markers. We provided a mechanistic insight toward regulation of Fra-1 by SIRT1 and demonstrated a direct link between the SIRT1-Fra-1 axis and EMT. Moreover, SIRT1 expression correlated positively with Fra-1 expression, metastasis and overall survival in patients with CRC. Taken together, our data provide a novel mechanistic role of SIRT1 in CRC metastasis, suggesting that SIRT1 may serve as a potential therapeutic target for metastatic CRC.

Hardy K, Wu F, Tu W, et al.
Identification of chromatin accessibility domains in human breast cancer stem cells.
Nucleus. 2016; 7(1):50-67 [PubMed] Free Access to Full Article Related Publications
Epithelial-to-mesenchymal transition (EMT) is physiological in embryogenesis and wound healing but also associated with the formation of cancer stem cells (CSCs). Many EMT signaling pathways are implicated in CSC formation, but the precise underlying mechanisms of CSC formation remain elusive. We have previously demonstrated that PKC is critical for EMT induction and CSC formation in inducible breast EMT/CSC models. Here, we used formaldehyde-assisted isolation of regulatory elements-sequencing (FAIRE-seq) to investigate DNA accessibility changes after PKC activation and determine how they influence EMT and CSC formation. During EMT, DNA accessibility principally increased in regions distant from transcription start sites, low in CpG content, and enriched with chromatin enhancer marks. ChIP-sequencing revealed that a subset of these regions changed from poised to active enhancers upon stimulation, with some even more acteylated in CSCs. While regions with increased accessibility were enriched for FOX, AP-1, TEAD, and TFAP2 motifs, those containing FOX and AP-1 motif were associated with increased expression of CSC-associated genes, while those with TFAP2 were associated with genes with increased expression in non-CSCs. Silencing of 2 members of the FOX family, FOXN2 and FOXQ1, repressed CSCs and the mesenchymal phenotype and inhibited the CSC gene signature. These novel, PKC-induced DNA accessibility regions help explain how the epigenomic plasticity of cells undergoing EMT leads to CSC gene activation.

Zhong BL, Bian LJ, Wang GM, et al.
Identification of key genes involved in HER2-positive breast cancer.
Eur Rev Med Pharmacol Sci. 2016; 20(4):664-72 [PubMed] Related Publications
OBJECTIVE: As an invasive cancer, breast cancer is the most common tumour in women and is with high mortality. To study the mechanisms of HER2-positive breast cancer, we analyzed microarray of GSE52194.
MATERIALS AND METHODS: GSE52194 was downloaded from Gene Expression Omnibus including 5 HER2-positive breast cancer samples and 3 normal breast samples. Using cuffdiff software, differentially expressed genes (DEGs) and differentially expressed long non-coding RNAs (DE-lncRNAs) were screened. Functions of the DEGs were analyzed by Gene Ontology (GO) and pathway enrichment analyses. Then, protein-protein interaction (PPI) network of the DEGs was constructed using Cytoscape and modules of the PPI network were screened by CFinder. Moreover, lncRNA-DEG pairs were screened.
RESULTS: Total 209 lncRNA transcriptions were predicted, and 996 differentially expressed transcriptions were screened. Besides, FOS had interaction relationships with EGR1 and SOD2 separately in module E and F of the PPI network for the DEGs. Moreover, there were many lncRNA-DEG pairs (e.g. TCONS_00003876-EGR1, TCONS_00003876-FOS, lnc-HOXC4-3:1-FOS, lnc-HOXC4-3:1-BCL6B, lnc-TEAD4-1:1-FOS and lnc-TEAD4-1:1-BCL6B), meanwhile, co-expressed DEGs of TCONS_00003876, lnc-HOXC4-3:1 and lnc-TEAD4-1:1 were enriched in p53 signaling pathway, MAPK signaling pathway and cancer-related pathways, respectively.
CONCLUSIONS: ANXA1, EGR1, BCL6, SOD2, FOS, TCONS_00003876, lnc-HOXC4-3:1 and lnc-TEAD4-1:1 might play a role in HER2-positive breast cancer.

Yamaguchi M, Osuka S, Weitzmann MN, et al.
Prolonged survival in pancreatic cancer patients with increased regucalcin gene expression: Overexpression of regucalcin suppresses the proliferation in human pancreatic cancer MIA PaCa-2 cells in vitro.
Int J Oncol. 2016; 48(5):1955-64 [PubMed] Related Publications
Approximately 90% of all pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is a highly aggressive malignancy and is one of the deadliest. This poor clinical outcome is due to the prominent resistance of pancreatic cancer to drug and radiation therapies. Regucalcin plays a pivotal role as a suppressor protein in signal transduction in various types of cells including tumor tissues. We demonstrated that the prolonged survival is induced in PDAC patients with increased regucalcin gene expression using a dataset of PDAC obtained from GEO database (GSE17891) together with the clinical annotation data file. Moreover, overexpression of regucalcin with full length was demonstrated to suppress the proliferation, cell death and migration in human pancreatic cancer MIA PaCa-2 (K-ras mutated) cells that possess resistance to drug and radiation therapies. Suppressive effects of regucalcin on cell proliferation and death were not seen in the cells overexpressed with regucalcin cDNA alternatively spliced variants (deleted exon 4 or deleted exon 4 and 5). Regucalcin was suggested to induce G1 and G2/M phase cell cycle arrest in MIA PaCa-2 cells. Suppressive effects of regucalcin on cell proliferation were independent of cell death. Overexpression of regucalcin was found to suppress signaling pathways including Akt, MAP kinase and SAPK/JNK, to increase the protein levels of p53, a tumor suppresser, and to decrease K-ras, c-fos and c-jun, a oncogene, by suppressing signaling pathways that are related to signaling of K-ras. Regucalcin may play a potential role as a suppressor protein in human pancreatic cancer.

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