FOSB

Gene Summary

Gene:FOSB; FBJ murine osteosarcoma viral oncogene homolog B
Aliases: AP-1, G0S3, GOS3, GOSB
Location:19q13.32
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. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:protein fosB
HPRD
Source:NCBIAccessed: 16 March, 2015

Ontology:

What does this gene/protein do?
Show (10)
Pathways:What pathways are this gene/protein implicaed in?
Show (1)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 16 March 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 16 March, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: FOSB (cancer-related)

Wegner MS, Wanger RA, Oertel S, et al.
Ceramide synthases CerS4 and CerS5 are upregulated by 17β-estradiol and GPER1 via AP-1 in human breast cancer cells.
Biochem Pharmacol. 2014; 92(4):577-89 [PubMed] Related Publications
Ceramide synthases (CerS) are important enzymes of the sphingolipid pathway, responsible for the production of ceramides with distinct chain lengths. In human breast cancer tissue, we detected a significant increase in CerS4 and CerS6 mRNA in estrogen receptor positive (ER+) cancer tissue. To clarify the molecular mechanism of this upregulation, we cloned CerS2, -4, -5 and CerS6 promoter and 3'-UTR fragments into luciferase reporter gene plasmids and determined luciferase activity in MCF-7 (ERα/β) and MDA-MB-231 (ERβ) cells after 17β-estradiol treatment. Only the activities of CerS4 and CerS5 promoter Luc constructs, as well as CerS2- and CerS5-3'-UTR Luc constructs increased after estradiol treatment in MCF-7 cells, and this could be inhibited by the anti-estrogen fulvestrant. Co-transfection with the G protein-coupled estrogen receptor 1 (GPER1) also enhanced CerS2, CerS4 and CerS6 promoter activity whereas CerS5 promoter activity was inhibited in both cell lines. Promoter deletion and mutation constructs from CerS4 and CerS5 promoters revealed that estradiol and GPER1 mediate their effects on both promoters by activating AP-1, most likely through dimerization of c-Jun and c-Fos. At least we could show, that cell proliferation induced by estradiol could be blocked by co-treatment with Fumonisin B1, indicating that upregulation of CerS in breast cancer cells by estrogen is important for cell proliferation and possibly tumor development. In conclusion, our data highlight transcriptional and posttranscriptional mechanisms regulating CerS expression in human cells which provide the basis for further studies investigating the regulation of CerS expression and ceramide synthesis after diverse stimuli in physiological and pathophysiological processess.

Pratheeshkumar P, Son YO, Divya SP, et al.
Luteolin inhibits Cr(VI)-induced malignant cell transformation of human lung epithelial cells by targeting ROS mediated multiple cell signaling pathways.
Toxicol Appl Pharmacol. 2014; 281(2):230-41 [PubMed] Related Publications
Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with the incidence of lung cancer. Inhibition of metal induced carcinogenesis by a dietary antioxidant is a novel approach. Luteolin, a natural dietary flavonoid found in fruits and vegetables, possesses potent antioxidant and anti-inflammatory activity. We found that short term exposure of human bronchial epithelial cells (BEAS-2B) to Cr(VI) (5μM) showed a drastic increase in ROS generation, NADPH oxidase (NOX) activation, lipid peroxidation, and glutathione depletion, which were significantly inhibited by the treatment with luteolin in a dose dependent manner. Treatment with luteolin decreased AP-1, HIF-1α, COX-2, and iNOS promoter activity induced by Cr(VI) in BEAS-2B cells. In addition, luteolin protected BEAS-2B cells from malignant transformation induced by chronic Cr(VI) exposure. Moreover, luteolin also inhibited the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) and VEGF in chronic Cr(VI) exposed BEAS-2B cells. Western blot analysis showed that luteolin inhibited multiple gene products linked to survival (Akt, Fak, Bcl-2, Bcl-xL), inflammation (MAPK, NF-κB, COX-2, STAT-3, iNOS, TNF-α) and angiogenesis (HIF-1α, VEGF, MMP-9) in chronic Cr(VI) exposed BEAS-2B cells. Nude mice injected with BEAS-2B cells chronically exposed to Cr(VI) in the presence of luteolin showed reduced tumor incidence compared to Cr(VI) alone treated group. Overexpression of catalase (CAT) or SOD2, eliminated Cr(VI)-induced malignant transformation. Overall, our results indicate that luteolin protects BEAS-2B cells from Cr(VI)-induced carcinogenesis by scavenging ROS and modulating multiple cell signaling mechanisms that are linked to ROS. Luteolin, therefore, serves as a potential chemopreventive agent against Cr(VI)-induced carcinogenesis.

Selvaraj N, Budka JA, Ferris MW, et al.
Extracellular signal-regulated kinase signaling regulates the opposing roles of JUN family transcription factors at ETS/AP-1 sites and in cell migration.
Mol Cell Biol. 2015; 35(1):88-100 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
JUN transcription factors bind DNA as part of the AP-1 complex, regulate many cellular processes, and play a key role in oncogenesis. The three JUN proteins (c-JUN, JUNB, and JUND) can have both redundant and unique functions depending on the biological phenotype and cell type assayed. Mechanisms that allow this dynamic switching between overlapping and distinct functions are unclear. Here we demonstrate that JUND has a role in prostate cell migration that is the opposite of c-JUN's and JUNB's. RNA sequencing reveals that opposing regulation by c-JUN and JUND defines a subset of AP-1 target genes with cell migration roles. cis-regulatory elements for only this subset of targets were enriched for ETS factor binding, indicating a specificity mechanism. Interestingly, the function of c-JUN and JUND in prostate cell migration switched when we compared cells with an inactive versus an active RAS/extracellular signal-regulated kinase (ERK) signaling pathway. We show that this switch is due to phosphorylation and activation of JUND by ERK. Thus, the ETS/AP-1 sequence defines a unique gene expression program regulated by the relative levels of JUN proteins and RAS/ERK signaling. This work provides a rationale for how transcription factors can have distinct roles depending on the signaling status and the biological function in question.

Plotnik JP, Budka JA, Ferris MW, Hollenhorst PC
ETS1 is a genome-wide effector of RAS/ERK signaling in epithelial cells.
Nucleic Acids Res. 2014; 42(19):11928-40 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
The RAS/ERK pathway is commonly activated in carcinomas and promotes oncogenesis by altering transcriptional programs. However, the array of cis-regulatory elements and trans-acting factors that mediate these transcriptional changes is still unclear. Our genome-wide analysis determined that a sequence consisting of neighboring ETS and AP-1 transcription factor binding sites is enriched near cell migration genes activated by RAS/ERK signaling in epithelial cells. In vivo screening of candidate ETS proteins revealed that ETS1 is specifically required for migration of RAS/ERK activated cells. Furthermore, both migration and transcriptional activation through ETS/AP-1 required ERK phosphorylation of ETS1. Genome-wide mapping of multiple ETS proteins demonstrated that ETS1 binds specifically to enhancer ETS/AP-1 sequences. ETS1 occupancy, and its role in cell migration, was conserved in epithelial cells derived from multiple tissues, consistent with a chromatin organization common to epithelial cell lines. Genome-wide expression analysis showed that ETS1 was required for activation of RAS-regulated cell migration genes, but also identified a surprising role for ETS1 in the repression of genes such as DUSP4, DUSP6 and SPRY4 that provide negative feedback to the RAS/ERK pathway. Consistently, ETS1 was required for robust RAS/ERK pathway activation. Therefore, ETS1 has dual roles in mediating epithelial-specific RAS/ERK transcriptional functions.

Fu J, Cheng L, Wang Y, et al.
The RNA-binding protein RBPMS1 represses AP-1 signaling and regulates breast cancer cell proliferation and migration.
Biochim Biophys Acta. 2015; 1853(1):1-13 [PubMed] Related Publications
The activator protein-1 (AP-1) transcription factor complex plays a crucial role in tumor growth and progression. However, how AP-1 transcriptional activity is repressed is not fully understood. Here, we show that RNA-binding protein with multiple splicing 1 (RBPMS1) physically and functionally interacts with AP-1 in vitro and in vivo. The RNA-recognition motif (RRM) and C-terminus of the RBPMS1 isoforms RBPMS1A and RBPMS1C, but not RBPMS1B, interacted with cFos, a member of the AP-1 family that dimerizes with cJun to stimulate AP-1 transcriptional activity. RBPMS1 did not associate with Jun proteins. RBPMS1A and RBPMS1C bound to the basic leucine zipper (bZIP) domain of cFos that mediates dimerization of AP-1 proteins. In addition, RBPMS1A-C interacted with the transcription factor Smad3, which was shown to interact with cJun and increase AP-1 transcriptional activity. RBPMS1 inhibited c-Fos or Smad3-mediated AP-1 transactivation and the expression of AP-1 target genes known to be the key regulators of cancer growth and progression, including vascular endothelial growth factor (VEGF) and cyclin D1. Mechanistically, RBPMS1 blocks the formation of the cFos/cJun or Smad3/cJun complex as well as the recruitment of cFos or Smad3 to the promoters of AP-1 target genes. In cultured cells and a mouse xenograft model, RBPMS1 inhibited the growth and migration of breast cancer cells through c-Fos or Smad3. These data suggest that RBPMS1 is a critical repressor of AP-1 signaling and RBPMS1 activation may be a useful strategy for cancer treatment.

Liu JJ, Lin XJ, Yang XJ, et al.
A novel AP-1/miR-101 regulatory feedback loop and its implication in the migration and invasion of hepatoma cells.
Nucleic Acids Res. 2014; 42(19):12041-51 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
MicroRNA-101 (miR-101) is frequently downregulated in various cancers. To date, the regulatory networks of miR-101 remain obscure. In this study, we demonstrated that miR-101 was mainly transcribed from human miR-101-2 and mouse miR-101bgene loci. Subsequent analyses revealed that activator protein-1 (AP-1) directly binded to the -17.4 to -16.4 k region upstream of pre-miR-101-2 and activated the expression of miR-101. On the other hand, miR-101 could inhibit the expression of ERK2 and c-Fos, two key factors of the AP-1 pathway, by binding to their 3'-UTRs. Furthermore, reintroduction of miR-101 efficiently suppressed the AP-1 activity and pri-miR-101-2 transcription. These data thus suggest a novel AP-1/miR-101 regulatory circuitry, that is, AP-1 promotes the transcription of miR-101, whereas the expression of miR-101 reduces the level of ERK2 and c-Fos and thereby attenuates the AP-1 signaling. Further investigation disclosed that the AP-1 activator TPA-induced MMP9 activity and the TPA-promoted migration and invasion of hepatoma cells were significantly attenuated by miR-101 but were enhanced by miR-101 inhibitor. Our results suggest that the AP-1/miR-101 feedback loop may prevent the excessive activation of metastatic signals imposed by ERK2/AP-1 and highlight the biological significance of miR-101 downregulation in cancer metastasis.

Moquet-Torcy G, Tolza C, Piechaczyk M, Jariel-Encontre I
Transcriptional complexity and roles of Fra-1/AP-1 at the uPA/Plau locus in aggressive breast cancer.
Nucleic Acids Res. 2014; 42(17):11011-24 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Plau codes for the urokinase-type plasminogen activator (uPA), critical in cancer metastasis. While the mechanisms driving its overexpression in tumorigenic processes are unknown, it is regulated by the AP-1 transcriptional complex in diverse situations. The AP-1 component Fra-1 being overexpressed in aggressive breast cancers, we have addressed its role in the overexpression of Plau in the highly metastatic breast cancer model cell line MDA-MB231 using ChIP, pharmacological and RNAi approaches. Plau transcription appears controlled by 2 AP-1 enhancers located -1.9 (ABR-1.9) and -4.1 kb (ABR-4.1) upstream of the transcription start site (TSS) of the uPA-coding mRNA, Plau-001, that bind Fra-1. Surprisingly, RNA Pol II is not recruited only at the Plau-001 TSS but also upstream in the ABR-1.9 and ABR-4.1 region. Most Pol II molecules transcribe short and unstable RNAs while tracking down toward the TSS, where there are converted into Plau-001 mRNA-productive species. Moreover, a minority of Pol II molecules transcribes a low abundance mRNA of unknown function called Plau-004 from the ABR-1.9 domain, whose expression is tempered by Fra-1. Thus, we unveil a heretofore-unsuspected transcriptional complexity at Plau in a reference metastatic breast cancer cell line with pleiotropic effects for Fra-1, providing novel information on AP-1 transcriptional action.

Han SS, Han S, Kamberos NL
Piperlongumine inhibits the proliferation and survival of B-cell acute lymphoblastic leukemia cell lines irrespective of glucocorticoid resistance.
Biochem Biophys Res Commun. 2014; 452(3):669-75 [PubMed] Related Publications
Piperlongumine (PL), a pepper plant alkaloid from Piper longum, has anti-inflammatory and anti-cancer properties. PL selectively kills both solid and hematologic cancer cells, but not normal counterparts. Here we evaluated the effect of PL on the proliferation and survival of B-cell acute lymphoblastic leukemia (B-ALL), including glucocorticoid (GC)-resistant B-ALL. Regardless of GC-resistance, PL inhibited the proliferation of all B-ALL cell lines, but not normal B cells, in a dose- and time-dependent manner and induced apoptosis via elevation of ROS. Interestingly, PL did not sensitize most of B-ALL cell lines to dexamethasone (DEX). Only UoC-B1 exhibited a weak synergistic effect between PL and DEX. All B-ALL cell lines tested exhibited constitutive activation of multiple transcription factors (TFs), including AP-1, MYC, NF-κB, SP1, STAT1, STAT3, STAT6 and YY1. Treatment of the B-ALL cells with PL significantly downregulated these TFs and modulated their target genes. While activation of AURKB, BIRC5, E2F1, and MYB mRNA levels were significantly downregulated by PL, but SOX4 and XBP levels were increased by PL. Intriguingly, PL also increased the expression of p21 in B-ALL cells through a p53-independent mechanism. Given that these TFs and their target genes play critical roles in a variety of hematological malignancies, our findings provide a strong preclinical rationale for considering PL as a new therapeutic agent for the treatment of B-cell malignancies, including B-ALL and GC-resistant B-ALL.

Limm K, Wallner S, Milenkovic VM, et al.
The metabolite 5'-methylthioadenosine signals through the adenosine receptor A2B in melanoma.
Eur J Cancer. 2014; 50(15):2714-24 [PubMed] Related Publications
Several recent studies have shown evidence supporting the general knowledge that tumour cells exhibit changes in metabolism. It is becoming increasingly important to understand how these metabolic changes in tumour cells promote carcinogenesis and disease progression. We recently discovered a lack of methylthioadenosine phosphorylase (MTAP) expression in melanoma, which resulted in an accumulation of the metabolite 5'-methylthioadenosine (MTA) in melanoma cells and in the extracellular environment. MTA was shown to affect cell proliferation of surrounding stroma cells and cell invasiveness and the activation of the transcription factor activator protein-1 (AP-1) in melanoma cells. In this study, we addressed the regulation of cellular signalling by extracellular MTA accumulation. By focusing on putative receptors that could modulate MTA signalling, we identified the adenosine receptor ADORA2B as an important candidate. Knockdown experiments and the use of specific agonists and antagonists confirmed a link between MTA and AP-1 signalling through the ADORA2B receptor. Interestingly, stimulation of the cells with MTA did not result in activation of the classical cyclic adenosine monophosphate (cAMP) signalling cascades or in Ca(2+)-dependent signalling. We instead showed protein kinase C (PKC) signalling to be involved in MTA-mediated AP-1 activation. In summary, we identified ADORA2B to be the specific receptor and signalling pathway for the metabolite MTA. These findings may influence the use of MTA in a therapeutic manner.

Qi L, Ding Y
Involvement of the CREB5 regulatory network in colorectal cancer metastasis.
Yi Chuan. 2014; 36(7):679-84 [PubMed] Related Publications
The signal regulatory network involved in colorectal cancer metastasis is complicated and thus the search for key control steps in the network is of great significance for unraveling colorectal cancer metastasis mechanism and finding drug-target site. Previous studies suggested that CREB5 (cAMP responsive element binding protein 5) might play key role in the metastatic signal network of colorectal cancer. Through colorectal cancer expression profile and enriching analysis of the effect of CREB5 gene expression levels on colorectal cancer molecular events, we found that these molecular events are correlated with tumor metastasis. Based on the feature that CREB5 could combine with c-Jun to form heterodimer, together with enriched binding sites for transcription factor AP-1, we identified 16 genes which were up-regulated in the CREB5 high-expression group, contained AP-1 binding sites, and participated in cancer pathway. The molecular network involving these 16 genes, in particular, CSF1R, MMP9, PDGFRB, FIGF and IL6, regulates cell migration. Therefore, CREB5 might accelerate the metastasis of colorectal cancer by regulating these five key genes.

Sutinen P, Malinen M, Heikkinen S, Palvimo JJ
SUMOylation modulates the transcriptional activity of androgen receptor in a target gene and pathway selective manner.
Nucleic Acids Res. 2014; 42(13):8310-9 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Androgen receptor (AR) plays an important regulatory role in prostate cancer. AR's transcriptional activity is regulated by androgenic ligands, but also by post-translational modifications, such as SUMOylation. To study the role of AR SUMOylation in genuine chromatin environment, we compared androgen-regulated gene expression and AR chromatin occupancy in PC-3 prostate cancer cell lines stably expressing wild-type (wt) or doubly SUMOylation site-mutated AR (AR-K386R,K520R). Our genome-wide gene expression analyses reveal that the SUMOylation modulates the AR function in a target gene and pathway selective manner. The transcripts that are differentially regulated by androgen and SUMOylation are linked to cellular movement, cell death, cellular proliferation, cellular development and cell cycle. Fittingly, SUMOylation mutant AR cells proliferate faster and are more sensitive to apoptosis. Moreover, ChIP-seq analyses show that the SUMOylation can modulate the chromatin occupancy of AR on many loci in a fashion that parallels their differential androgen-regulated expression. De novo motif analyses reveal that FOXA1, C/EBP and AP-1 motifs are differentially enriched at the wtAR- and the AR-K386R,K520R-preferred genomic binding positions. Taken together, our data indicate that SUMOylation does not simply repress the AR activity, but it regulates AR's interaction with the chromatin and the receptor's target gene selection.

Zhang R, Kang KA, Piao MJ, et al.
Epigenetic alterations are involved in the overexpression of glutathione S-transferase π-1 in human colorectal cancers.
Int J Oncol. 2014; 45(3):1275-83 [PubMed] Related Publications
Glutathione S-transferase π-1 (GSTP-1) is a member of the glutathione S-transferase enzyme superfamily, which catalyzes the conjugation of electrophiles to glutathione during the process of detoxification. In this study, the epigenetic alterations of GSTP-1 expression in human colorectal cancers and the underlying mechanisms were investigated. In 10 colon cancer patients, proteomic analysis revealed that expression of GSTP-1 protein was higher in tumor tissues than in paired adjacent normal tissues. Likewise, in 7 of 10 colon cancer patients, GSTP-1 protein expression was more than 1.5-fold higher in tumor tissues than in adjacent normal tissues, as determined by western blotting. Immunohistochemical data confirmed that GSTP-1 protein was expressed at higher levels in colon cancer tissues compared to normal mucosa. GSTP-1 enzyme activity was closely correlated with GSTP-1 protein expression in colon cancer patients. Consistent with this, GSTP-1 mRNA, protein and activity levels were higher in the colorectal cancer cell lines Caco-2, HCT-116, HT-29, SNU-407 and SNU-1033 compared to the normal colon cell line FHC. Methylation-specific PCR results indicated that the high levels of GSTP-1 in human colorectal cancer cell lines were likely due to the lower degree of promoter methylation in colon cancer cell lines compared to the normal colon cell line, consistent with findings in colon cancer patients. Moreover, the levels of specific activator-protein complexes and histone marks were higher in human colorectal cancer cells compared to the normal human colon cell line, whereas the repressor protein complexes exhibited the opposite pattern. Furthermore, chromatin immunoprecipitation assays demonstrated that expression levels of the transcription factors AP-1 and SP-1 were correlated with the upregulation of GSTP-1 expression in colorectal cancer cells. Finally, knockdown of GSTP-1 promoted the sensitivity of SNU-407 cells to the anticancer agent 5-fluorouracil. These data indicate that GSTP-1 may serve as a clinically useful biomarker of colon cancer and a target for anti-colon cancer drugs.

Lee YR, Kim KM, Jeon BH, Choi S
The hexane fraction of Naematoloma sublateritium extract suppresses the TNF-α-induced metastatic potential of MDA-MB-231 breast cancer cells through modulation of the JNK and p38 pathways.
Int J Oncol. 2014; 45(3):1284-92 [PubMed] Related Publications
Naematoloma sublateritium (Fr.) P. Karst is a basidiomycete that has been used as traditional medicine. N. sublateritium produces a triterpenoid antitumor compound, clavaric acid, but, in general, the effects of N. sublateritium constituents against tumor invasion and metastasis have been poorly studied. To investigate the inhibitory effect of N. sublateritium constituents on highly invasive and metastatic tumor cells, the TNF-α-stimulated human breast cancer cell line, MDA-MB‑231 was treated with the hexane fraction of an N. sublateritium extract (HFNS). Non-cytotoxic concentrations of HFNS markedly inhibited the invasion and migration of the MDA-MB‑231 cells in the Matrigel invasion assay and wound-healing analysis, respectively. Gelatin zymography showed that HFNS suppressed the activity of MMP-9, but not of MMP-2. Immunoblotting demonstrated that treatment with HFNS had decreased the level of MMP-9 and urokinase plasminogen activator-1 (uPA-1), but had upregulated expression of the endogenous inhibitor proteins, including TIMP-1,-2, and PAI-1, in a dose-dependent manner. Furthermore, HFNS suppressed the phosphorylation of p38 and JNK1/2, but not that of ERK1/2. This was confirmed by pretreatment of cells with specific inhibitors prior to stimulation with TNF-α. HFNS treatment also led to a dose-dependent inhibition of the DNA-binding activities of AP-1 and NFκB, which are downstream targets of JNK and p38. These data suggested that HFNS inhibits the metastatic potential of MDA-MB‑231 cells by inhibiting the phosphorylation of JNK/p38 and reducing AP-1 and NFκB DNA-binding activities. Therefore, HFNS may be a potential therapeutic agent against metastasis of breast cancer.

Yamazaki S, Miyoshi N, Kawabata K, et al.
Quercetin-3-O-glucuronide inhibits noradrenaline-promoted invasion of MDA-MB-231 human breast cancer cells by blocking β₂-adrenergic signaling.
Arch Biochem Biophys. 2014; 557:18-27 [PubMed] Related Publications
Endogenous catecholamines such as adrenaline (A) and noradrenaline (NA) are released from the adrenal gland and sympathetic nervous system during exposure to stress. The adrenergic system plays a central role in stress signaling, and excessive stress was found to be associated with increased production of reactive oxygen species (ROS). Overproduction of ROS induces oxidative damage in tissues and causes the development of diseases such as cancer. In this study, we investigated the effects of quercetin-3-O-glucuronide (Q3G), a circulating metabolite of quercetin, which is a type of natural flavonoid, on the catecholamine-induced β2-adrenergic receptor (β2-AR)-mediated response in MDA-MB-231 human breast cancer cells expressing β2-AR. Treatment with A or NA at concentrations above 1μM generated significant levels of ROS, and NA treatment induced the gene expression of heme oxygenase-1 (HMOX1), and matrix metalloproteinase-2 (MMP-2) and -9 (MMP9). Inhibitors of p38 MAP kinase (SB203580), cAMP-dependent protein kinase (PKA) (H-89), activator protein-1 (AP-1) transcription factor (SR11302), and NF-κB and AP-1 (Tanshinone IIA) decreased MMP2 and MMP9 gene expression. NA also enhanced cAMP induction, RAS activation and phosphorylation of ERK1/2. These results suggested that the cAMP-PKA, MAPK, and ROS-NF-κB pathways are involved in β2-AR signaling. Treatment with 0.1μM Q3G suppressed ROS generation, cAMP and RAS activation, phosphorylation of ERK1/2 and the expression of HMOX1, MMP2, and MMP9 genes. Furthermore, Q3G (0.1μM) suppressed invasion of MDA-MB-231 breast cancer cells and MMP-9 induction, and inhibited the binding of [(3)H]-NA to β2-AR. These results suggest that Q3G may function to suppress invasion of breast cancer cells by controlling β2-adrenergic signaling, and may be a dietary chemopreventive factor for stress-related breast cancer.

Lee HM, Kim KS, Kim J
A comparative study of the effects of inhibitory cytokines on human natural killer cells and the mechanistic features of transforming growth factor-beta.
Cell Immunol. 2014; 290(1):52-61 [PubMed] Related Publications
The major factors and mechanisms by which natural killer (NK) cells are inhibited in cancer patients have not yet been well defined. In this study, we conducted a comparative analysis of the effects of TGF-β, IL-10, and IL-4 on primary NK cells, and it was demonstrated that (1) TGF-β most potently inhibited the overall function of NK cells. (2) It appears that TGF-β reduced the tyrosine phosphorylation of Syk and the expression of c-myc. (3) It was also found that the IL-2-induced promoter-binding activities of C-myb, AP-1, CREB, and AR were also completely suppressed upon TGF-β treatment. Interestingly, TGF-β also completely suppressed other transcription factors, which are constitutively activated. Among these factors, we further confirmed roles of AP-1 in NK-92 cell activation through c-jun and MEK1 inhibitor assay. Our study provides insight into the effects of TGF-β in modulating NK cell functions.

Volk A, Li J, Xin J, et al.
Co-inhibition of NF-κB and JNK is synergistic in TNF-expressing human AML.
J Exp Med. 2014; 211(6):1093-108 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Leukemic stem cells (LSCs) isolated from acute myeloid leukemia (AML) patients are more sensitive to nuclear factor κB (NF-κB) inhibition-induced cell death when compared with hematopoietic stem and progenitor cells (HSPCs) in in vitro culture. However, inadequate anti-leukemic activity of NF-κB inhibition in vivo suggests the presence of additional survival/proliferative signals that can compensate for NF-κB inhibition. AML subtypes M3, M4, and M5 cells produce endogenous tumor necrosis factor α (TNF). Although stimulating HSPC with TNF promotes necroptosis and apoptosis, similar treatment with AML cells (leukemic cells, LCs) results in an increase in survival and proliferation. We determined that TNF stimulation drives the JNK-AP1 pathway in a manner parallel to NF-κB, leading to the up-regulation of anti-apoptotic genes in LC. We found that we can significantly sensitize LC to NF-κB inhibitor treatment by blocking the TNF-JNK-AP1 signaling pathway. Our data suggest that co-inhibition of both TNF-JNK-AP1 and NF-κB signals may provide a more comprehensive treatment paradigm for AML patients with TNF-expressing LC.

Zhu Y, Zhu L, Lu L, et al.
Role and mechanism of the alkylglycerone phosphate synthase in suppressing the invasion potential of human glioma and hepatic carcinoma cells in vitro.
Oncol Rep. 2014; 32(1):431-6 [PubMed] Related Publications
Ether lipids have been implicated in the exacerbation of human tumors. Accumulating evidence suggests that the alkylglycerone phosphate synthase (AGPS) is involved in the suppression of some types of tumor. However, the role and molecular mechanism of AGPS in the invasion of human glioma and hepatic carcinoma remain unclear. In the present study, using AGPS-knockdown human glioma U87 and hepatic carcinoma HepG2 cell lines, we explored the role of AGPS, as well as its molecular mechanism, in invasion in vitro. It was demonstrated that silencing AGPS expression resulted in a decreased expression of cellular lipids such as LPA, LPAe and PGE2, adhesion, invasion potential and arrested cell cycle in tumor cells. The expression of invasion-related genes such as MMP-2/9, E-cadherin and CD44 showed marked changes in AGPS‑knockdown cells. In addition, we found that AGPS regulated the activity of the MAPK pathway, as well as the transcriptional activity of Twist, AP-1, and Snail. The results demonstrated that AGPS negatively regulated the invasion potential of glioma and hepatic carcinoma cells by modulating the expression of relevant genes and activity of the MAPK pathway. Therefore, AGPS may be a potential glioma and hepatic carcinoma therapeutic target.

Zhao C, Qiao Y, Jonsson P, et al.
Genome-wide profiling of AP-1-regulated transcription provides insights into the invasiveness of triple-negative breast cancer.
Cancer Res. 2014; 74(14):3983-94 [PubMed] Related Publications
Triple-negative breast cancer (TNBC) is an aggressive clinical subtype accounting for up to 20% of all breast cancers, but its malignant determinants remain largely undefined. Here, we show that in TNBC the overexpression of Fra-1, a component of the transcription factor AP-1, offers prognostic potential. Fra-1 depletion or its heterodimeric partner c-Jun inhibits the proliferative and invasive phenotypes of TNBC cells in vitro. Similarly, RNAi-mediated attenuation of Fra-1 or c-Jun reduced cellular invasion in vivo in a zebrafish tumor xenograft model. Exploring the AP-1 cistrome and the AP-1-regulated transcriptome, we obtained insights into the transcriptional regulatory networks of AP-1 in TNBC cells. Among the direct targets identified for Fra-1/c-Jun involved in proliferation, adhesion, and cell-cell contact, we found that AP-1 repressed the expression of E-cadherin by transcriptional upregulation of ZEB2 to stimulate cell invasion. Overall, this work illuminates the pathways through which TNBC cells acquire invasive and proliferative properties.

Han J, Xie Y, Lan F, et al.
Additive effects of EGF and IL-1β regulate tumor cell migration and invasion in gastric adenocarcinoma via activation of ERK1/2.
Int J Oncol. 2014; 45(1):291-301 [PubMed] Related Publications
Growth and inflammatory factors are associated with poor prognosis in gastric adenocarcinoma (GA); however, the additive effects of growth and inflammatory factors in GA remain unclear. In this study, we investigated the ability of epidermal growth factor (EGF) and interleukin (IL-1β) to activate extracellular signal-regulated kinase (ERK)1/2 in GA cells, and correlated the relationships between their roles with the metastatic potential both in GA cells and GA tissues. The effects of EGF, IL-1β and EGF plus IL-1β in AGS and MKN-45 GA cells were examined using western blotting, Transwell migration and invasion assays, immunocytochemical staining and an activator protein (AP)-1 luciferase reporter gene assay, and was further characterized in GA tissues by immunohistochemistry. The results exhibited that EGF and IL-1β additively activated ERK1/2, increased migration and invasion than either EGF or IL-1β alone in AGS and MKN-45 cells. The mechanisms were involved in upregulating MMP-9 expression through increasing AP-1 transcriptional activity via ERK1/2 pathway; these effects were dose-dependently inhibited by silencing ERK1/2 or using U0126. In vivo data also confirmed that the overexpression of p-ERK1/2 in GA tissues correlated well with the EGF, IL-1β, EGF plus IL-1β, and was associated with metastasis, which was well correlation with the expression of MMP-9 and c-fos (AP-1). The results demonstrate that growth and inflammatory factors play an important role in metastasis of GA by additively activating ERK-1/2 and AP-1, and upregulating MMP-9. As both cytokines contribute to the migration and invasion of GA cells, EGF/IL-1β/ERK1/2 pathways may be key pathways closely associated with GA progression.

Lee JY, Chung TW, Choi HJ, et al.
A novel cantharidin analog N-benzylcantharidinamide reduces the expression of MMP-9 and invasive potentials of Hep3B via inhibiting cytosolic translocation of HuR.
Biochem Biophys Res Commun. 2014; 447(2):371-7 [PubMed] Related Publications
Invasion and metastasis are major causes of malignant tumor-associated mortality. The present study aimed to investigate the molecular events underlying inhibitory effect of N-benzylcantharidinamide, a novel synthetic analog of cantharidin, on matrix metalloproteinase-9 (MMP-9)-mediated invasion in highly metastatic hepatocellular carcinoma Hep3B cells. In this investigation, among six analogs of cantharidin, only N-benzylcantharidinamide has the inhibitory action on MMP-9 expression at non-toxic dose. The MMP-9 expression and invasion of Hep3B cells were significantly suppressed by treatment of N-benzylcantharidinamide in a dose-dependent manner. On the other hand, the transcriptional activity of MMP-9 promoter and nuclear levels of NF-κB and AP-1 as the main transcriptional factors inducing MMP-9 expression were not affected by it although the level of MMP-9 mRNA was reduced by treatment of N-benzylcantharidinamide. Interestingly, the stability of MMP-9 mRNA was significantly reduced by N-benzylcantharidinamide-treatment. In addition, the cytosolic translocation of human antigen R (HuR), which results in the increase of MMP-9 mRNA stability through interaction of HuR with 3'-untranslated region of MMP-9 mRNA, was suppressed by treatment of N-benzylcantharidinamide, in a dose-dependent manner. Taken together, it was demonstrated, for the first time, that N-benzylcantharidinamide suppresses MMP-9 expression by reducing HuR-mediated MMP-9 mRNA stability for the inhibition of invasive potential in highly metastatic Hep3B cells.

Yang F, Nam S, Brown CE, et al.
A novel berbamine derivative inhibits cell viability and induces apoptosis in cancer stem-like cells of human glioblastoma, via up-regulation of miRNA-4284 and JNK/AP-1 signaling.
PLoS One. 2014; 9(4):e94443 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Glioblastoma (GBM) is the most common primary brain tumor, accounting for approximately 40% of all central nervous system malignancies. Despite standard treatment consisting of surgical resection, radiotherapy and/or chemotherapy, the prognosis for GBM is poor; with a median survival of 14.6 months. The cancer stem cell or cancer-initiating cell model has provided a new paradigm for understanding development and recurrence of GBM following treatment. Berbamine (BBM) is a natural compound derived from the Berberis amurensis plant, and along with its derivatives, has been shown to exhibit antitumor activity in several cancers. Here, we reported that a novel synthetic Berbamine derivative, BBMD3, inhibits cell viability and induces apoptosis of cancer stem-like cells (CSCs) in a time- and dose-dependent manner when the CSCs from four GBM patients (PBT003, PBT008, PBT022, and PBT030) were cultured. These CSCs grew in neurospheres and expressed CD133 and nestin as markers. Treatment with BBMD3 destroyed the neurosphere morphology, and led to the induction of apoptosis in the CSCs. Induction of apoptosis in these CSCs is dependent upon activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). MicroRNA-4284 (miR-4284) was shown to be over-expressed about 4-fold in the CSCs following BBMD3 treatment. Furthermore, transfection of synthetic anti-sense oligonucleotide against human miR-4284 partially blocked the anticancer effects of BBMD3 on the GBM derived CSCs. BBMD3 also increased phosphorylation of the c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK), resulting in an increase expression of phosphorylated c-Jun and total c-Fos; the major components of transcriptional factor AP-1. The JNK-c-Jun/AP-1 signaling pathway plays an important role in the induction of apoptosis in response to UV irradiation and some drug treatments. Targeting glioblastoma stem-like cells with BBMD3 is therefore novel, and may have promise as an effective therapeutic strategy for treating GBM patients.

Wu H, Zhang K, Gong P, et al.
A novel functional TagSNP Rs7560488 in the DNMT3A1 promoter is associated with susceptibility to gastric cancer by modulating promoter activity.
PLoS One. 2014; 9(3):e92911 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
DNA-methyltransferase (DNMT)-3A which contains DNMT3A1 and DNMT3A2 isoforms have been suggested to play a crucial role in carcinogenesis and showed aberrant expression in most cancers. Accumulated evidences also indicated that single nucleotide polymorphisms (SNP) in DNMT genes were associated with susceptibility to different tumors. We hypothesized that genetic variants in DNMT3A1 promoter region are associated with gastric cancer risk. We selected the tagSNPs from the HapMap database for the Chinese and genotyped in a case-control study to evaluate the association with gastric cancer (GC) in a Chinese population. We identified that the functional tagSNP rs7560488 T>C associated with a significantly increased risk of GC. In vitro functional analysis by luciferase reporter assay and EMSA indicated that the tagSNP rs7560488 T>C substantially altered transcriptional activity of DNMT3A1 gene via influencing the binding of some transcriptional factors, although a definite transcriptional factor remains to be established. Compared with TT homozygotes, subjects who were TC heterozygotes and CC homozygotes exhibited a reduced expression of DNMT3A1. Furthermore, stratified analysis showed that individuals who harbor TC or CC genotypes less than 60 years old were more susceptible to GC. Our results suggest that the genetic variations in the DNMT3A1 promoter contribute to the susceptibility to GC and also provide an insight that tagSNP rs7560488 T>C may be a promising biomarker for predicting GC genetic susceptibility and a valuable information in GC pathogenesis.

Fitzgerald KA, Evans JC, McCarthy J, et al.
The role of transcription factors in prostate cancer and potential for future RNA interference therapy.
Expert Opin Ther Targets. 2014; 18(6):633-49 [PubMed] Related Publications
INTRODUCTION: Prostate cancer is a leading cause of cancer-related death in men and current treatments offer only a modest survival benefit in advanced stages of the disease. RNA interference (RNAi) is a therapeutic option that has received great attention in recent years with the potential to treat a variety of disorders, including prostate cancer. Transcription factors are cellular proteins that can up-regulate or down-regulate the transcription of genes and offer promising therapeutic targets.
AREAS COVERED: This review will focus on transcription factors that have been identified as key molecules in drug resistance, disease progression and metastases in prostate cancer, which may offer potential as therapeutic targets for RNAi in the future.
EXPERT OPINION: By identifying therapeutically viable transcription factor targets in prostate cancer, it is hoped that treatment strategies using RNAi will augment the effect of current chemotherapy regimens, slow disease progression and reduce metastases in prostate cancer, resulting in disease regression.

Diesch J, Sanij E, Gilan O, et al.
Widespread FRA1-dependent control of mesenchymal transdifferentiation programs in colorectal cancer cells.
PLoS One. 2014; 9(3):e88950 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Tumor invasion and metastasis involves complex remodeling of gene expression programs governing epithelial homeostasis. Mutational activation of the RAS-ERK is a frequent occurrence in many cancers and has been shown to drive overexpression of the AP-1 family transcription factor FRA1, a potent regulator of migration and invasion in a variety of tumor cell types. However, the nature of FRA1 transcriptional targets and the molecular pathways through which they promote tumor progression remain poorly understood. We found that FRA1 was strongly expressed in tumor cells at the invasive front of human colorectal cancers (CRCs), and that its depletion suppressed mesenchymal-like features in CRC cells in vitro. Genome-wide analysis of FRA1 chromatin occupancy and transcriptional regulation identified epithelial-mesenchymal transition (EMT)-related genes as a major class of direct FRA1 targets in CRC cells. Expression of the pro-mesenchymal subset of these genes predicted adverse outcomes in CRC patients, and involved FRA-1-dependent regulation and cooperation with TGFβ signaling pathway. Our findings reveal an unexpectedly widespread and direct role for FRA1 in control of epithelial-mesenchymal plasticity in CRC cells, and suggest that FRA1 plays an important role in mediating cross talk between oncogenic RAS-ERK and TGFβ signaling networks during tumor progression.

Ruan M, Zhang Z, Li S, et al.
Activation of Toll-like receptor-9 promotes cellular migration via up-regulating MMP-2 expression in oral squamous cell carcinoma.
PLoS One. 2014; 9(3):e92748 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
PURPOSE: Activation of Toll like receptors (TLRs) signaling has been implicated in promoting malignant cell invasion and metastatic potential. Previously we demonstrated that increased TLR-9 expression predicted poor survival in oral cancer patients. The objective of this study is to further investigate the roles and potential molecular mechanisms of TLR-9 signaling in human oral cancer cell invasion.
METHODS: Cell migration, invasion and protein expression were detected by wound healing assay, Transwell chambers model and western blot. The secretion and activity levels of metalloproteinases-2/9 were quantified by ELISA and Gelatin zymography. EMSA and ChIP assays were employed to detect the activity of AP-1signal pathway. TLR-9 siRNA transfection was used to regulate the expression and activity of TLR-9 in oral cancer cell line HB cells.
RESULT: The results of both wound healing assay and in vitro Transwell assay revealed that activation of TLR-9 induced dose- and time- dependent migration and invasion of HB cells. An increased expression, secretion and activity of MMP-2 were observed upon the treatment of CpG-ODN. The TLR-9 signaling-mediated MMP-2 expression appeared to be a consequence of AP-1 activation, because that their DNA binding activity was enhanced by CpG-ODN treatment. All these influences were efficiently repressed by the knockdown of TLR-9 through siRNA or pretreatment of an AP-1 inhibitor.
CONCLUSION: Activation of TLR-9 signaling could promote human oral cancer HB cells invasion with the induction of MMP-2 presentation by attenuating AP-1 binding activity, suggesting a novel anti-metastatic application for TLR-9 targeted therapy in oral cancer in the future.

Katsuyama M, Ibi M, Matsumoto M, et al.
Clioquinol increases the expression of VGF, a neuropeptide precursor, through induction of c-Fos expression.
J Pharmacol Sci. 2014; 124(4):427-32 [PubMed] Related Publications
Clioquinol was used extensively in the mid-1900s as an amebicide to treat indigestion and diarrhea. It was eventually withdrawn from the market because it was linked to subacute myelo-optic neuropathy (SMON) in Japan. However, the pathogenesis of SMON has not yet been elucidated in detail. As reported previously, we performed a global analysis on human neuroblastoma cells using DNA chips. The global analysis and quantitative PCR demonstrated that the mRNA level of VGF (nonacronymic), the precursor of neuropeptides involved in pain reactions, was significantly increased when SH-SY5Y and IMR-32 neuroblastoma cells were treated with clioquinol. Promoter analyses in SH-SY5Y cells revealed that a region responsive to clioquinol exists between -1381 and -1349 of the human VGF gene, which contains an activator protein (AP)-1 site-like sequence. The introduction of mutations at this site significantly reduced clioquinol-induced transcriptional activation. Clioquinol induced the expression of the AP-1 family transcription factors, c-Jun and c-Fos. Electrophoresis mobility shift assays demonstrated that c-Jun and c-Fos could bind to the AP-1 site at -1374/-1368 in SH-SY5Y cells treated with clioquinol. RNA interference against c-Fos significantly suppressed clioquinol-induced VGF mRNA expression. These results suggest that the clioquinol-induced expression of c-Fos mediates the induction of VGF expression.

Selvaraj N, Budka JA, Ferris MW, et al.
Prostate cancer ETS rearrangements switch a cell migration gene expression program from RAS/ERK to PI3K/AKT regulation.
Mol Cancer. 2014; 13:61 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: The RAS/ERK and PI3K/AKT pathways induce oncogenic gene expression programs and are commonly activated together in cancer cells. Often, RAS/ERK signaling is activated by mutation of the RAS or RAF oncogenes, and PI3K/AKT is activated by loss of the tumor suppressor PTEN. In prostate cancer, PTEN deletions are common, but, unlike other carcinomas, RAS and RAF mutations are rare. We have previously shown that over-expression of "oncogenic" ETS transcription factors, which occurs in about one-half of prostate tumors due to chromosome rearrangement, can bypass the need for RAS/ERK signaling in the activation of a cell migration gene expression program. In this study we test the role of RAS/ERK and PI3K/AKT signaling in the function of oncogenic ETS proteins.
RESULTS: We find that oncogenic ETS expression negatively correlates with RAS and RAF mutations in prostate tumors. Furthermore, the oncogenic ETS transcription factors only increased cell migration in the absence of RAS/ERK activation. In contrast to RAS/ERK, it has been reported that oncogenic ETS expression positively correlates with PI3K/AKT activation. We identified a mechanistic explanation for this finding by showing that oncogenic ETS proteins required AKT signaling to activate a cell migration gene expression program through ETS/AP-1 binding sequences. Levels of pAKT correlated with the ability of oncogenic ETS proteins to increase cell migration, but this process did not require mTORC1.
CONCLUSIONS: Our findings indicate that oncogenic ETS rearrangements cause a cell migration gene expression program to switch from RAS/ERK control to PI3K/AKT control and provide a possible explanation for the high frequency of PTEN, but not RAS/RAF mutations in prostate cancer.

Jung HS, Seo YR, Yang YM, et al.
Gα12gep oncogene inhibits FOXO1 in hepatocellular carcinoma as a consequence of miR-135b and miR-194 dysregulation.
Cell Signal. 2014; 26(7):1456-65 [PubMed] Related Publications
The high mortality rate of hepatocellular carcinoma (HCC) is associated with its fast-growing malignancy. In tumor microenvironments, certain GPCRs are coupled to Gα12 for signal transduction. Given the role of forkhead box O1 (FOXO1) in the inhibition of various tumors, this study investigated whether increase of Gα12 in HCC causes FOXO1 repression, and if so, whether this event occurs through microRNA dysregulation. Overexpression of an active mutant of Gα12 (Gα12QL) decreased FOXO1 levels, whereas knockdown of Gα12 had the opposite effect. Of the microRNAs targeting FOXO1, miR-135b levels were markedly increased by Gα12 signaling, which led to FOXO1 repression as shown by the experiments using mimic, antisense oligonucleotide or siRNA. Gα12QL increased the primary form of miR-135b by activating JunB (or c-Jun)/AP-1. Consistently, knockdown of JunB (or c-Jun) decreased miR-135b levels, thereby increasing FOXO1. Moreover, Gα12QL induced MDM2, the deficiency of which facilitated FOXO1 accumulation. In addition, Gα12QL repressed miR-194 cluster gene products (194/192/215), which contributed to MDM2-mediated FOXO1 repression. In functional assays, Gα12QL facilitated tumor cell growth with alterations in cell cycle-associated protein levels, which was antagonized by enforced expression of FOXO1. In human HCCs, FOXO1 levels were decreased as compared with the surrounding liver tissue. Moreover, decrease of FOXO1 or miR-194 was statistically significant between stages T1 and T2, whereas increase of miR-135b discriminated tumor stage T3a versus T1/T2. In conclusion, Gα12gep oncogene inhibits FOXO1, which may result from the inhibition of FOXO1 de novo synthesis by miR-135b in conjunction with MDM2-mediated destabilization of FOXO1.

Leibovich-Rivkin T, Liubomirski Y, Meshel T, et al.
The inflammatory cytokine TNFα cooperates with Ras in elevating metastasis and turns WT-Ras to a tumor-promoting entity in MCF-7 cells.
BMC Cancer. 2014; 14:158 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: In the present study we determined the relative contribution of two processes to breast cancer progression: (1) Intrinsic events, such as activation of the Ras pathway and down-regulation of p53; (2) The inflammatory cytokines TNFα and IL-1β, shown in our published studies to be highly expressed in tumors of >80% of breast cancer patients with recurrent disease.
METHODS: Using MCF-7 human breast tumor cells originally expressing WT-Ras and WT-p53, we determined the impact of the above-mentioned elements and cooperativity between them on the expression of CXCL8 (ELISA, qRT-PCR), a member of a "cancer-related chemokine cluster" that we have previously identified. Then, we determined the mechanisms involved (Ras-binding-domain assays, Western blot, luciferase), and tested the impact of Ras + TNFα on angiogenicity (chorioallantoic membrane assays) and on tumor growth at the mammary fat pad of mice and on metastasis, in vivo.
RESULTS: Using RasG12V that recapitulates multiple stimulations induced by receptor tyrosine kinases, we found that RasG12V alone induced CXCL8 expression at the mRNA and protein levels, whereas down-regulation of p53 did not. TNFα and IL-1β potently induced CXCL8 expression and synergized with RasG12V, together leading to amplified CXCL8 expression. Testing the impact of WT-Ras, which is the common form in breast cancer patients, we found that WT-Ras was not active in promoting CXCL8; however, TNFα has induced the activation of WT-Ras: joining these two elements has led to cooperative induction of CXCL8 expression, via the activation of MEK, NF-κB and AP-1. Importantly, TNFα has led to increased expression of WT-Ras in an active GTP-bound form, with properties similar to those of RasG12V. Jointly, TNFα + Ras activities have given rise to increased angiogenesis and to elevated tumor cell dissemination to lymph nodes.
CONCLUSIONS: TNFα cooperates with Ras in promoting the metastatic phenotype of MCF-7 breast tumor cells, and turns WT-Ras into a tumor-supporting entity. Thus, in breast cancer patients the cytokine may rescue the pro-cancerous potential of WT-Ras, and together these two elements may lead to a more aggressive disease. These findings have clinical relevance, suggesting that we need to consider new therapeutic regimens that inhibit Ras and TNFα, in breast cancer patients.

Sanz-Pamplona R, Berenguer A, Cordero D, et al.
Aberrant gene expression in mucosa adjacent to tumor reveals a molecular crosstalk in colon cancer.
Mol Cancer. 2014; 13:46 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
BACKGROUND: A colorectal tumor is not an isolated entity growing in a restricted location of the body. The patient's gut environment constitutes the framework where the tumor evolves and this relationship promotes and includes a complex and tight correlation of the tumor with inflammation, blood vessels formation, nutrition, and gut microbiome composition. The tumor influence in the environment could both promote an anti-tumor or a pro-tumor response.
METHODS: A set of 98 paired adjacent mucosa and tumor tissues from colorectal cancer (CRC) patients and 50 colon mucosa from healthy donors (246 samples in total) were included in this work. RNA extracted from each sample was hybridized in Affymetrix chips Human Genome U219. Functional relationships between genes were inferred by means of systems biology using both transcriptional regulation networks (ARACNe algorithm) and protein-protein interaction networks (BIANA software).
RESULTS: Here we report a transcriptomic analysis revealing a number of genes activated in adjacent mucosa from CRC patients, not activated in mucosa from healthy donors. A functional analysis of these genes suggested that this active reaction of the adjacent mucosa was related to the presence of the tumor. Transcriptional and protein-interaction networks were used to further elucidate this response of normal gut in front of the tumor, revealing a crosstalk between proteins secreted by the tumor and receptors activated in the adjacent colon tissue; and vice versa. Remarkably, Slit family of proteins activated ROBO receptors in tumor whereas tumor-secreted proteins transduced a cellular signal finally activating AP-1 in adjacent tissue.
CONCLUSIONS: The systems-level approach provides new insights into the micro-ecology of colorectal tumorogenesis. Disrupting this intricate molecular network of cell-cell communication and pro-inflammatory microenvironment could be a therapeutic target in CRC patients.

Disclaimer: This site is for educational purposes only; it can not be used in diagnosis or treatment.

Cite this page: Cotterill SJ. FOSB, Cancer Genetics Web: http://www.cancer-genetics.org/FOSB.htm Accessed:

Creative Commons License
This page in Cancer Genetics Web by Simon Cotterill is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Note: content of abstracts copyright of respective publishers - seek permission where appropriate.

 [Home]    Page last revised: 16 March, 2015     Cancer Genetics Web, Established 1999