Expression of c-fos was associated with clinicopathologic characteristics and prognosis in pancreatic cancer

MIF/NR3C2 axis regulates glucose metabolism reprogramming in pancreatic cancer through MAPK-ERK and AP-1 pathways

Inflammation and aberrant cellular metabolism are widely recognized as hallmarks of cancer. In pancreatic ductal adenocarcinoma (PDAC), inflammatory signaling and metabolic reprogramming are tightly interwoven, playing pivotal roles in the pathogenesis and progression of the disease. However, the regulatory functions of inflammatory mediators in metabolic reprogramming in pancreatic cancer have not been fully explored. Earlier, we demonstrated that pro-inflammatory mediator macrophage migration inhibitory factor (MIF) enhances disease progression by inhibiting its downstream transcriptional factor nuclear receptor subfamily 3 group C member 2 (NR3C2). Here, we provide evidence that MIF and NR3C2 interactively regulate metabolic reprogramming, resulting in MIF-induced cancer growth and progression in PDAC. MIF positively correlates with the HK1 (hexokinase 1), HK2 (hexokinase 2) and LDHA (lactate dehydrogenase) expression and increased pyruvate and lactate production in PDAC patients. Additionally, MIF augments glucose uptake and lactate efflux by upregulating HK1, HK2 and LDHA expression in pancreatic cancer cells in vitro and in mouse models of PDAC. Conversely, a reduction in HK1, HK2 and LDHA expression is observed in tumors with high NR3C2 expression in PDAC patients. NR3C2 suppresses HK1, HK2 and LDHA expression, thereby inhibiting glucose uptake and lactate efflux in pancreatic cancer. Mechanistically, MIF-mediated regulation of glycolytic metabolism involves the activation of the mitogen-activated protein kinase-ERK signaling pathway, whereas NR3C2 interacts with the activator protein 1 to regulate glycolysis. Our findings reveal an interactive role of the MIF/NR3C2 axis in regulating glucose metabolism supporting tumor growth and progression and may be a potential target for designing novel approaches for improving disease outcome.

Phylogenetic and Expression Analysis of Fos Transcription Factors in Zebrafish

Members of the FOS protein family regulate gene expression responses to a multitude of extracellular signals and are dysregulated in several pathological states. Whilst mouse genetic models have provided key insights into the tissue-specific functions of these proteins in vivo, little is known about their roles during early vertebrate embryonic development. This study examined the potential of using zebrafish as a model for such studies and, more broadly, for investigating the mechanisms regulating the functions of Fos proteins in vivo. Through phylogenetic and sequence analysis, we identified six zebrafish FOS orthologues, fosaa, fosab, fosb, fosl1a, fosl1b, and fosl2, which show high conservation in key regulatory domains and post-translational modification sites compared to their equivalent human proteins. During embryogenesis, zebrafish fos genes exhibit both overlapping and distinct spatiotemporal patterns of expression in specific cell types and tissues. Most fos genes are also expressed in a variety of adult zebrafish tissues. As in humans, we also found that expression of zebrafish FOS orthologs is induced by oncogenic BRAF-ERK signalling in zebrafish melanomas. These findings suggest that zebrafish represent an alternate model to mice for investigating the regulation and functions of Fos proteins in vertebrate embryonic and adult tissues, and cancer.

Tescalcin promotes highly invasive papillary thyroid microcarcinoma by regulating FOS/ERK signaling pathway

Background

Part of papillary thyroid microcarcinoma (PTMC) has a high risk of tumor invasion and metastasis, which may occur in the regional lymph node metastasis or distant metastasis, severely threatening the life of patients. Invasion and metastasis are tightly involved in the proliferation, migration and invasion in cancer. This study aimed to investigate the role of tescalcin (TESC) in the proliferation, migration and invasion of PTMC.

Methods

The expressions of TESC in PTMC tissues and cells were detected by immunohistochemistry or qRT-PCR. Then, TPC-1 and BHT101 cells transfected with TESC-RNAi were used for the transcriptome sequencing. The proliferation, apoptosis, migration and invasion of TPC-1 and BHT101 cells were detected by CCK-8, colony formation, flow cytometric assay, transwell migration and scratch test. Moreover, TESC-RNAi transfected TPC-1 and BHT101 cells were subcutaneously injected into mice. Tumor volume and weight were calculated, and the positive rate of Ki-67 was determined by immunohistochemistry. Finally, the levels of c-Fos, ERK1/2 and p-ERK1/2 were determined by western blot.

Results

The expressions of TESC in PTMC tissues and cell lines were prominently enhanced. Transcriptome sequencing results showed that c-Fos was decreased in TPC-1 and BHT101 cells transfected with TESC-RNAi, which was associated with multiple different signaling pathways including the MAPK signaling pathway. Furthermore, TESC promoted the progress of PTMC by regulating the expression of c-Fos, which might be associated with the ERK signaling pathway.

Conclusions

TESC promoted the growth and metastasis of PTMC through regulating c-Fos/ERK1/2.

The Adipokine Component in the Molecular Regulation of Cancer Cell Survival, Proliferation and Metastasis

A hormonal imbalance may disrupt the rigorously monitored cellular microenvironment by hampering the natural homeostatic mechanisms. The most common example of such hormonal glitch could be seen in obesity where the uprise in adipokine levels is in virtue of the expanding bulk of adipose tissue. Such aberrant endocrine signaling disrupts the regulation of cellular fate, rendering the cells to live in a tumor supportive microenvironment. Previously, it was believed that the adipokines support cancer proliferation and metastasis with no direct involvement in neoplastic transformations and tumorigenesis. However, the recent studies have reported discrete mechanisms that establish the direct involvement of adipokine signaling in tumorigenesis. Moreover, the individual adipokine profile of the patients has never been considered in the prognosis and staging of the disease. Hence, the present manuscript has focused on the reported extensive mechanisms that culminate the basis of poor prognosis and diminished survival rate in obese cancer patients.

Prediction and identification of synergistic compound combinations against pancreatic cancer cells

Resistance to current therapies is common for pancreatic cancer and hence novel treatment options are urgently needed. In this work, we developed and validated a computational method to select synergistic compound combinations based on transcriptomic profiles from both the disease and compound side, combined with a pathway scoring system, which was then validated prospectively by testing 30 compounds (and their combinations) on PANC-1 cells. Some compounds selected as single agents showed lower GI50 values than the standard of care, gemcitabine. Compounds suggested as combination agents with standard therapy gemcitabine based on the best performing scoring system showed on average 2.82-5.18 times higher synergies compared to compounds that were predicted to be active as single agents. Examples of highly synergistic in vitro validated compound pairs include gemcitabine combined with Entinostat, thioridazine, loperamide, scriptaid and Saracatinib. Hence, the computational approach presented here was able to identify synergistic compound combinations against pancreatic cancer cells.

Targeting AP-1 transcription factors by CRISPR in the prostate

Prostate cancer is the second most diagnosed cancer in men. It is a slow progressing cancer, but when the disease reaches an advanced stage, treatment options are limited. Sequencing analyses of cancer samples have identified genes that can potentially drive disease progression. We implemented the CRISPR/Cas9 technology to simultaneously manipulate multiple genes in the murine prostate and thus to functionally test putative cancer driver genes in vivo. The activating protein-1 (AP-1) transcription factor is associated with many different cancer types, with the proto-oncogenes JUN and FOS being the two most intensely studied subunits. We analyzed expression of FOS and JUNB in human prostate cancer datasets and observed decreased expression in advanced stages. By applying CRISPR/Cas9 technology, the role of these two transcription factors in prostate cancer progression was functionally tested. Our data revealed that loss of either JunB or Fos in the context of Pten loss drives prostate cancer progression to invasive disease. Furthermore, loss of Fos increases Jun expression, and CRISPR inactivation of Jun in this context decreases cell proliferation. Overall, these in vivo studies reveal that JunB and Fos exhibit a tumor suppressor function by repressing invasive disease, whereas Jun is oncogenic and increases cell proliferation. This demonstrates that AP-1 factors are implicated in prostate cancer progression at different stages and display a dual function as tumor suppressor and as an oncogene in cancer progression.

In vivo CRISPR inactivation of Fos promotes prostate cancer progression by altering the associated AP-1 subunit Jun

Prostate cancer is a major global health concern with limited treatment options for advanced disease. Its heterogeneity challenges the identification of crucial driver genes implicated in disease progression. Activating protein-1 (AP-1) transcription factor is associated with cancer since the first identification of its subunits, the proto-oncogenes JUN and FOS. Whereas both JUN and FOS, have been implicated in prostate cancer, this study provides the first functional evidence that FOS acts as a tumor suppressor during prostate cancer progression and invasion. Data mining revealed decreased FOS expression in prostate cancer and a further downregulation in metastatic disease, consistent with FOS expression in cell lines derived from different prostate cancer stages. FOS deficiency in prostate cancer cell lines increases cell proliferation and induces oncogenic pathway alterations. Importantly, in vivo CRISPR/Cas9-mediated Fos and Pten double mutation in murine prostate epithelium results in increased proliferation and invasiveness compared to the abrogation of Pten alone. Interestingly, enhanced Jun expression is observed in the murine prostatic intraepithelial neoplasia lacking Fos. CRISPR/Cas9-mediated knockout of Jun combined with Fos and Pten deficiency diminishes the increased proliferation rate in vivo, but not the ability to form invasive disease. Overall, we demonstrate that loss of Fos promotes disease progression from clinical latent prostate cancer to advanced disease through accelerated proliferation and invasiveness, partly through Jun.

Selective antagonism of cJun for cancer therapy

The activator protein-1 (AP-1) family of transcription factors modulate a diverse range of cellular signalling pathways into outputs which can be oncogenic or anti-oncogenic. The transcription of relevant genes is controlled by the cellular context, and in particular by the dimeric composition of AP-1. Here, we describe the evidence linking cJun in particular to a range of cancers. This includes correlative studies of protein levels in patient tumour samples and mechanistic understanding of the role of cJun in cancer cell models. This develops an understanding of cJun as a focal point of cancer-altered signalling which has the potential for therapeutic antagonism. Significant work has produced a range of small molecules and peptides which have been summarised here and categorised according to the binding surface they target within the cJun-DNA complex. We highlight the importance of selectively targeting a single AP-1 family member to antagonise known oncogenic function and avoid antagonism of anti-oncogenic function.

The lncRNA RUNX1-IT1 regulates C-FOS transcription by interacting with RUNX1 in the process of pancreatic cancer proliferation, migration and invasion

Numerous long noncoding RNAs (lncRNAs) are aberrantly expressed in pancreatic cancer (PC); however, their functions and mechanisms in cancer progression are largely unknown. In this study, we identified a novel PC-associated lncRNA, RUNX1-IT1, that was significantly upregulated in PC patient samples from multiple centers and associated with poor prognosis. In vitro and in vivo, alterations in RUNX1-IT1 expression markedly affected PC proliferation, migration and invasion. RUNX1-IT1 contributed to the progression of PC by interacting with the adjacent gene RUNX1. Rescue experiments showed that RUNX1 reduced the cancer-promoting effect of RUNX1-IT1. RNA-seq analysis after silencing RUNX1-IT1 and RUNX1 highlighted alterations in the common target C-FOS. Mechanistically, we demonstrated that RUNX1-IT1 was a trans-acting factor that participated in the proliferation, migration and invasion of PC by recruiting RUNX1 to the C-FOS gene promoter. Furthermore, RUNX1-IT1 enhanced the transcription of the RUNX1 gene, indicating its potential as a cis-regulatory RNA involved in the upstream regulation of RUNX1. Overall, RUNX1-IT1 is a crucial oncogenic lncRNA that activates C-FOS expression by regulating and recruiting RUNX1 and is a potential prognostic biomarker and therapeutic target for PC.

Nuclear Tau, p53 and Pin1 Regulate PARN-Mediated Deadenylation and Gene Expression

While nuclear tau plays a role in DNA damage response (DDR) and chromosome relaxation, the mechanisms behind these functions are not fully understood. Here, we show that tau forms complex(es) with factors involved in nuclear mRNA processing such as tumor suppressor p53 and poly(A)-specific ribonuclease (PARN) deadenylase. Tau induces PARN activity in different cellular models during DDR, and this activation is further increased by p53 and inhibited by tau phosphorylation at residues implicated in neurological disorders. Tau's binding factor Pin1, a mitotic regulator overexpressed in cancer and depleted in Alzheimer's disease (AD), also plays a role in the activation of nuclear deadenylation. Tau, Pin1 and PARN target the expression of mRNAs deregulated in AD and/or cancer. Our findings identify novel biological roles of tau and toxic effects of hyperphosphorylated-tau. We propose a model in which factors involved in cancer and AD regulate gene expression by interactions with the mRNA processing machinery, affecting the transcriptome and suggesting insights into alternative mechanisms for the initiation and/or developments of these diseases.

Targeting acquired oncogenic burden in resilient pancreatic cancer: a novel benefit from marine polyphenols

The upsurge of marine-derived therapeutics for cancer treatment is evident, with many drugs in clinical use and in clinical trials. Seaweeds harbor large amounts of polyphenols and their anti-cancer benefit is linear to their anti-oxidant activity. Our studies identified three superlative anti-cancer seaweed polyphenol drug candidates (SW-PD). We investigated the acquisition of oncogenic burden in radiation-resilient pancreatic cancer (PC) that could drive tumor relapse, and elucidated the efficacy of SW-PD candidates as adjuvants in genetically diverse in vitro systems and a mouse model of radiation-residual disease. QPCR profiling of 88 oncogenes in therapy-resilient PC cells identified a 'shared' activation of 40 oncogenes. SW-PD pretreatment inflicted a significant mitigation of acquired (shared) oncogenic burden, in addition to drug- and cell-line-specific repression signatures. Tissue microarray with IHC of radiation-residual tumors in mice signified acquired cellular localization of key oncoproteins and other critical architects. Conversely, SW-PD treatment inhibited the acquisition of these critical drivers of tumor genesis, dissemination, and evolution. Heightened death of resilient PC cells with SW-PD treatment validated the translation aspects. The results defined the acquisition of oncogenic burden in resilient PC and demonstrated that the marine polyphenols effectively target the acquired oncogenic burden and could serve as adjuvant(s) for PC treatment.

Chemerin and Cancer

Chemerin is a multifunctional adipokine with established roles in inflammation, adipogenesis and glucose homeostasis. Increasing evidence suggest an important function of chemerin in cancer. Chemerin's main cellular receptors, chemokine-like receptor 1 (CMKLR1), G-protein coupled receptor 1 (GPR1) and C-C chemokine receptor-like 2 (CCRL2) are expressed in most normal and tumor tissues. Chemerin's role in cancer is considered controversial, since it is able to exert both anti-tumoral and tumor-promoting effects, which are mediated by different mechanisms like recruiting innate immune defenses or activation of endothelial angiogenesis. For this review article, original research articles on the role of chemerin and its receptors in cancer were considered, which are listed in the PubMed database. Additionally, we included meta-analyses of publicly accessible DNA microarray data to elucidate the association of expression of chemerin and its receptors in tumor tissues with patients' survival.

DNA hypermethylation of aurora kinase A in hepatitis C virus‑positive hepatocellular carcinoma

Changes in the methylation levels of tumor suppressor genes or proto-oncogenes are involved in the pathogenesis of hepatitis C virus (HCV) infection-induced hepatocellular carcinoma (HCC). The aim of the present study was to identify novel aberrantly methylated differentially expressed genes by integrating mRNA expression profile (GSE19665 and GSE62232) and methylation profile (GSE60753) microarrays downloaded from the Gene Expression Omnibus database. Functional enrichment analysis of screened genes was performed using the DAVID software and BinGO database. Protein-protein interaction (PPI) networks were constructed using the STRING database, followed by module analysis with MCODE software. The transcriptional and translational expression levels of crucial genes were confirmed using The Cancer Genome Atlas (TCGA) datasets and Human Protein Atlas database (HPA). A total of 122 downregulated/hypermethylated genes and 63 upregulated/hypomethylated genes were identified. These genes were enriched in the Gene Ontology biological processes terms of ‘inflammatory response’ [Fos proto-oncogene, AP-1 transcription factor subunit (FOS)] and ‘cell cycle process’ [aurora kinase A (AURKA), cyclin dependent kinase inhibitor 3 (CDKN3) and ubiquitin conjugating enzyme E2 C (UBE2C)]. PPI network and module analysis indicated that human oncogenes FOS, AURKA, CDKN3 and UBE2C may be hub genes. mRNA, protein expression and methylation levels of AURKA and FOS were validated by TCGA and HPA data. In conclusion, aberrantly methylated AURKA and FOS may be potential therapeutic targets for HCV-positive HCC.

EGFR is required for FOS-dependent bone tumor development via RSK2/CREB signaling

Osteosarcoma (OS) is a rare tumor of the bone occurring mainly in young adults accounting for 5% of all childhood cancers. Because of the limited therapeutic options, there has been no survival improvement for OS patients in the past 40 years. The epidermal growth factor receptor (EGFR) is highly expressed in OS; however, its clinical relevance is unclear. Here, we employed an autochthonous c‐Fos‐dependent OS mouse model (H2‐c‐fosLTR) and human OS tumor biopsies for preclinical studies aimed at identifying novel biomarkers and therapeutic benefits of anti‐EGFR therapies. We show that EGFR deletion/inhibition results in reduced tumor formation in H2‐c‐fosLTR mice by directly inhibiting the proliferation of cancer‐initiating osteoblastic cells by a mechanism involving RSK2/CREB‐dependent c‐Fos expression. Furthermore, OS patients with co‐expression of EGFR and c‐Fos exhibit reduced overall survival. Preclinical studies using human OS xenografts revealed that only tumors expressing both EGFR and c‐Fos responded to anti‐EGFR therapy demonstrating that c‐Fos can be considered as a novel biomarker predicting response to anti‐EGFR treatment in OS patients.

Analysis of Transcription Factor-Related Regulatory Networks Based on Bioinformatics Analysis and Validation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for a significant proportion of liver cancer, which has become the second most common cause of cancer-related mortality worldwide. To investigate the potential mechanisms of invasion and progression of HCC, bioinformatics analysis and validation by qRT-PCR were performed. We found 237 differentially expressed genes (DEGs) including EGR1, FOS, and FOSB, which were three cancer-related transcription factors. Subsequently, we constructed TF-gene network and miRNA-TF-mRNA network based on data obtained from mRNA and miRNA expression profiles for analysis of HCC. We found that 42 key genes from the TF-gene network including EGR1, FOS, and FOSB were most enriched in the p53 signaling pathway. The qRT-PCR data confirmed that mRNA levels of EGR1, FOS, and FOSB all were decreased in HCC tissues. In addition, we confirmed that the mRNA levels of CCNB1, CCNB2, and CHEK1, three key markers of the p53 signaling pathway, were all increased in HCC tissues by bioinformatics analysis and qRT-PCR validation. Therefore, we speculated that miR-181a-5p, which was upregulated in HCC tissues, could regulate FOS and EGR1 to promote the invasion and progression of HCC by p53 signaling pathway. Overall, the study provides support for the possible mechanisms of progression in HCC.

c-Fos over-expression promotes radioresistance and predicts poor prognosis in malignant glioma

c-Fos is a major component of activator protein (AP)-1 complex. It has been implicated in cell differentiation, proliferation, angiogenesis, invasion, and metastasis. To investigate the role of c-Fos in glioma radiosensitivity and to understand the underlying molecular mechanisms, we downregulated c-Fos gene expression by lentivirus-mediated shRNA in glioma cell lines and subsequently analyzed the radiosensitivity, DNA damage repair capacity, and cell cycle distribution. Finally, we explored its prognostic value in 41 malignant glioma patients by immunohistochemistry. Our results showed that silencing c-Fos sensitized glioma cells to radiation by increasing radiation-induced DNA double strand breaks (DSBs), disturbing the DNA damage repair process, promoting G2/M cell cycle arrest, and enhancing apoptosis. c-Fos protein overexpression correlated with poor prognosis in malignant glioma patients treated with standard therapy. Our findings provide new insights into the mechanism of radioresistance in malignant glioma and identify c-Fos as a potentially novel therapeutic target for malignant glioma patients.

C-fos upregulates P-glycoprotein, contributing to the development of multidrug resistance in HEp-2 laryngeal cancer cells with VCR-induced resistance

Background

Laryngeal cancer tends to have a very poor prognosis due to the unsatisfactory efficacy of chemotherapy for this cancer. Multidrug resistance (MDR) is the main cause of chemotherapy failure. The proto-oncogene c-fos has been shown to be involved in the development of MDR in several tumor types, but few studies have evaluated the relationship between c-fos and MDR in laryngeal cancer. We investigated the role of c-fos in MDR development in laryngeal cancer cells (cell line: human epithelial type 2, HEp-2) using the chemotherapeutic vincristine (VCR).

Methods

HEp-2/VCR drug resistance was established by selection against an increasing drug concentration gradient. The expressions of c-fos and multidrug resistance 1 (mdr1) were measured using qPCR and western blot. C-fos overexpression or knockdown was performed in various cells. The intracellular rhodamine-123 (Rh-123) accumulation assay was used to detect the transport capacity of P-glycoprotein (P-gp, which is encoded by the mdr1 gene).

Results

HEp-2 cells with VCR-induced resistance (HEp-2/VCR cells) were not only resistant to VCR but also evolved cross-resistance to other chemotherapeutic drugs. The expressions of the c-fos and mdr1genes were significantly higher in the HEp-2/VCR cells than in control cells. C-fos overexpression in HEp-2 cells (c-fos WT) resulted in increased P-gp expression and increased the IC₅₀ for 5-FU. C-fos knockdown in the HEp-2/VCR cells (c-fos shRNA) resulted in decreased P-gp expression and decreased IC₅₀ for 5-FU. An intracellular Rh-123 accumulation assay showed that the mean intracellular fluorescence intensity (MFI) was lower in the HEp-2/VCR cells than in HEp-2 cells. C-fos WT cells also showed lower MFI. By contrast, c-fos shRNA cells exhibited a higher MFI than the control group.

Conclusion

C-fos increased the expression of P-gp and mdr1 in the HEp-2/VCR cells, and enhanced the efflux function of the cells, thereby contributing to the development of MDR.

Comprehensive analysis of normal adjacent to tumor transcriptomes

Histologically normal tissue adjacent to the tumor (NAT) is commonly used as a control in cancer studies. However, little is known about the transcriptomic profile of NAT, how it is influenced by the tumor, and how the profile compares with non-tumor-bearing tissues. Here, we integrate data from the Genotype-Tissue Expression project and The Cancer Genome Atlas to comprehensively analyze the transcriptomes of healthy, NAT, and tumor tissues in 6506 samples across eight tissues and corresponding tumor types. Our analysis shows that NAT presents a unique intermediate state between healthy and tumor. Differential gene expression and protein–protein interaction analyses reveal altered pathways shared among NATs across tissue types. We characterize a set of 18 genes that are specifically activated in NATs. By applying pathway and tissue composition analyses, we suggest a pan-cancer mechanism of pro-inflammatory signals from the tumor stimulates an inflammatory response in the adjacent endothelium.

Normal tissue adjacent to the tumour (NAT) is often used as a control in cancer studies. Here, the authors analyse across cancer types the transcriptomes of healthy, NAT, and tumour tissues, and find that NAT presents a unique state, potentially due to inflammatory response of the NAT to the tumour tissue.

G-protein-coupled receptor kinase 2 in pancreatic cancer: clinicopathologic and prognostic significance

G-protein-coupled receptor kinase 2 (GRK2) was found to regulate biological behaviors in some cancers, including pancreatic cancer (PC). However, its clinicopathologic and prognostic implications in cancer remain unclear. This study was designed to address the issues in PC. Expression of GRK2 was measured by Western blotting and tissue microarray-based immunohistochemical staining in 3 and 171 patients with PC, respectively. The H-score was used to evaluate the staining results. In addition, GRK2 expression was correlated with clinicopathologic variables and overall survival. Finally, the prognostic value of GRK2 was validated in a publically available PC dataset, GSE21501. It was suggested that GRK2 expression was highly up-regulated in 2 out of 3 tumor samples, in contrast to corresponding non-tumor ones. Furthermore, H-score of GRK2 staining was significantly higher in tumor than in non-tumor tissues. Tumoral expression of GRK2 was significantly associated with T stage. Univariate analysis showed that high GRK2 expression in tumor tissues was predictive for poor overall survival of PC. However, GRK2 expression was not identified as an independent prognostic marker in multivariate Cox regression test, although close to the statistical significance. In dataset GSE21501, GRK2 was also revealed to be prognostic. Our data establish that GRK2 is overexpressed in PC, and might serve as a potential indicator of unfavorable prognosis.