Overexpression of c-fos promotes cell invasion and migration via CD44 pathway in oral squamous cell carcinoma

Global gene expression profile of proliferative verrucous leukoplakia and its underlying biological disease mechanisms

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a rare and enigmatic oral potentially malignant disorder which almost invariably results in oral squamous cell carcinoma (OSCC). The aims of this project were to use transcriptome profiling to characterise PVL gene expression patterns for biomarker identification and gain insight into the molecular aetiopathogenesis of PVL.

METHODS

Forty-three oral cavity mucosal biopsies from 32 patients with oral lesions clinically compatible with either PVL or non-PVL conventional oral leukoplakia (OLK) underwent transcriptome profiling by RNA sequencing. Data was analysed by hierarchical clustering, differential gene expression, functional enrichment and network analysis, sparse partial least squares discriminant analysis sPLS-DA, and immune cell phenotypic estimation.

RESULTS

We found 464 genes significantly differentially expressed at least 2-fold between PVL and non-PVL OLK (193 up and 271 down). HOX genes, including HOXA1 and HOXB7, keratin-associated proteins (KRTAPs) and olfactory receptor G proteins (OR) were significantly upregulated in PVL. Other upregulated genes in PVL included FOS, WNT16 and IFNA1. Pathway analysis showed that there was a significant downregulation of connective tissue signalling in PVL. Classifying multivariate models based upon 22 genes discriminated PVL from non-PVL OLK. Bioinformatic profiling showed that immune cell profiles in PVL and OLK were similar except that fibroblast markers were reduced in PVL.

CONCLUSION

These results demonstrate that PVL and conventional OLK are molecularly distinct with upregulation of many cancer-associated genes. They provide insight into the pathogenesis of PVL and show that biomarker based molecular diagnostics is feasible to discriminate and inform diagnosis and management.

The effect of c-Fos on the prognosis, proliferation, and invasion of oral squamous cell carcinoma

OBJECTIVE

This study aimed to determine the role of c-Fos in growth and invasion of oral squamous cell carcinoma (OSCC).

METHODS

Immunohistochemistry was used to assess c-Fos expression in 94 OSCC tissues and 30 adjacent normal tissues, the correlation between c-Fos expression and clinicopathological characteristics was examined, and Kaplan-Meier and Cox analysis were used to investigate the role of c-Fos in predicting the prognosis of OSCC patients. The effects of c-Fos on the growth and invasion of OSCC were disclosed by overexpression and knockdown of c-Fos. Furthermore, based on bioinformatics prediction, the effect of miR-155-5p on c-Fos expression was examined, and dual-luciferase reporter assay system was used to determine whether miR-155-5p regulated the transcriptional activity of c-Fos in OSCC.

RESULTS

c-Fos was markedly increased in OSCC tissues and cells. c-Fos upregulation indicates a poor prognosis in OSCC patients, and c-Fos promotes cell proliferation, migration, and invasion in OSCC. miR-155-5p could regulate the expression and the transcriptional activity of c-Fos by directly targeting the c-Fos 3'-UTR.

CONCLUSION

This study demonstrated that c-Fos contributed to the progression of OSCC and may act as a potential target for OSCC therapy, and a potential prognostic biomarker of OSCC.

Correlation of hsa miR-101-5p and hsa miR-155-3p Expression With c-Fos in Patients of Oral Submucous Fibrosis (OSMF) and Oral Squamous Cell Carcinoma (OSCC)

Aim

MicroRNAs have been widely acknowledged as a diagnostic, prognostic, and/or therapeutic biomarker for the progression of OSCC, but the correlation of hsa-miR-101-5p and hsa-miR-155-3p is yet to be established with c-Fos in OSCC and OSMF.

Methodology

An observational study enrolled 40 patients divided into 2 groups: Group I-21 OSMF patients without malignant transformation, Group II-19 patients with locally advanced, large-operable, or metastatic OSCC, after applying inclusion and exclusion criteria. Both miRNAs were extracted and analyzed from the tissue sample excised from the involved site. The linear regression analysis of the expression of hsa-miR-155-3p, hsa-miR-101-5p, and levels of c-fos in OSMF and OSCC patients and its correlation for habits, age, and gender were evaluated.

Results

The expression of hsa-miR-101-5p was 0.81 times downregulated in OSCC tissue compared to OSMF, whereas hsa-miR-155-3p and c-fos were both upregulated 9.30 times and 1.75 times, respectively, in OSCC tissue. In Gutkha and tobacco chewers, the hsa-miR-155-3p expression could explain 12.3% (p = 0.031) for Gutkha chewers, whereas c-fos could explain 38.6% of the cases (p = 0.020) for tobacco chewers. The expression of hsa-miR-101-5p and hsa-miR-155-3p explained 43.7% and 59.5% of OSCC cases in alcoholics, respectively. Interestingly, in non-alcoholics, hsa-miR-155-3p and hsa-miR-101-5p were significant predictors of OSCC.

Conclusion

Downregulation of tumor-suppressor hsa-miR-101-5p and upregulation of proto-onco hsa-miR-155-3p is responsible for intricate regulation of the progression of OSMF to OSCC via deregulated expression of c-Fos and tobacco chewing and advancing age is significant contributors for OSCC.

Anti-Inflammatory Activities of an Anti-Histamine Drug, Loratadine, by Suppressing TAK1 in AP-1 Pathway

Loratadine is an anti-histamine routinely used for treating allergies. However, recent findings have shown that Loratadine may also have anti-inflammatory functions, while their exact mechanisms have not yet been fully uncovered. In this paper, we investigated whether Loratadine can be utilized as an anti-inflammatory drug through a series of in vitro and in vivo experiments using a murine macrophage cell line and an acute gastritis mouse model. Loratadine was found to dramatically reduce the expression of pro-inflammatory genes, including MMP1, MMP3, and MMP9, and inhibit AP-1 transcriptional activation, as demonstrated by the luciferase assay. Therefore, we decided to further explore its role in the AP-1 signaling pathway. The expression of c-Jun and c-Fos, AP-1 subunits, was repressed by Loratadine and, correspondingly, the expression of p-JNK, p-MKK7, and p-TAK1 was also inhibited. In addition, Loratadine was able to reduce gastric bleeding in acute gastritis-induced mice; Western blotting using the stomach samples showed reduced p-c-Fos protein levels. Loratadine was shown to effectively suppress inflammation by specifically targeting TAK1 and suppressing consequent AP-1 signaling pathway activation and inflammatory cytokine production.

A Functional Network Model of the Metastasis Suppressor PEBP1/RKIP and Its Regulators in Breast Cancer Cells

Drug screening strategies focus on quantifying the phenotypic effects of different compounds on biological systems. High-throughput technologies have the potential to understand further the mechanisms by which these drugs produce the desired outcome. Reverse causal reasoning integrates existing biological knowledge and measurements of gene and protein abundances to infer their function. This approach can be employed to appraise the existing biological knowledge and data to prioritize targets for cancer therapies. We applied text mining and a manual literature search to extract known interactions between several metastasis suppressors and their regulators. We then identified the relevant interactions in the breast cancer cell line MCF7 using a knockdown dataset. We finally adopted a reverse causal reasoning approach to evaluate and prioritize pathways that are most consistent and responsive to drugs that inhibit cell growth. We evaluated this model in terms of agreement with the observations under treatment of several drugs that produced growth inhibition of cancer cell lines. In particular, we suggested that the metastasis suppressor PEBP1/RKIP is on the receiving end of two significant regulatory mechanisms. One involves RELA (transcription factor p65) and SNAI1, which were previously reported to inhibit PEBP1. The other involves the estrogen receptor (ESR1), which induces PEBP1 through the kinase NME1. Our model was derived in the specific context of breast cancer, but the observed responses to drug treatments were consistent in other cell lines. We further validated some of the predicted regulatory links in the breast cancer cell line MCF7 experimentally and highlighted the points of uncertainty in our model. To summarize, our model was consistent with the observed changes in activity with drug perturbations. In particular, two pathways, including PEBP1, were highly responsive and would be likely targets for intervention.

Expression and significance of laminin receptor in squamous cell carcinoma of the tongue

BACKGROUND

Laminin receptor is a non-integrin cell-surface receptor that binds laminin present on the basement membrane. It has been reported to be associated with infiltration and metastasis of various malignant tumors. However, no studies regarding tongue cancer have been reported. This study aimed to clarify the role of laminin receptor in squamous cell carcinoma of the tongue.

METHODS

We performed immunohistochemical staining of specimens from 66 patients with squamous cell carcinoma of the tongue and assessed laminin receptor expression and clinicopathological factors. As epithelial-mesenchymal transition has been shown to be associated with infiltration and metastasis of malignant tumors, staining for E-cadherin, vimentin, and N-cadherin were also performed.

RESULTS

Of 20 patients with postoperative recurrence, 14 exhibited high laminin receptor expression (p = 0.0025). Kaplan-Meier analysis revealed a significantly shorter time to postoperative recurrence for the high laminin receptor expression group than that for the low laminin receptor expression group (p = 0.0008). Based on multivariate analyses for postoperative recurrence, high laminin receptor expression was associated with poor prognosis (high expression vs. low expression; HR =3.19, 95% CI =0.92-11.08; p = 0.0682). There was a correlation between laminin receptor and N-cadherin (p = 0.0089) but not between laminin receptor and E-cadherin (p = 0.369) or vimentin (p = 0.4221).

CONCLUSION

These results suggest that high laminin receptor expression is a useful prognostic factor for postoperative recurrence and may be a target for molecular therapy to treat squamous cell carcinoma of the tongue.

CD44 Sorted Cells Have an Augmented Potential for Proliferation, Epithelial-Mesenchymal Transition, Stemness, and a Predominantly Inflammatory Cytokine and Angiogenic Secretome

Cancer stem cells (CSCs) have garnered attention with their potential for early diagnosis and prognosis of oral squamous cell carcinoma (OSCC). It is still indistinct whether CSCs are recognized with a specific set of characteristics. The present study aimed to assess the association of CD44 with stemness-related, Epithelial Mesenchymal Transition EMT-related genes and the secretome of the CSCs. The single-cell suspension from primary OSCC tumors was prepared by enzymatic digestion and the cells were cultured in-vitro. The cancer stem cells were isolated by CD44+ selection using magnetic cell-sorting. The expression of CD44, proliferation rate, gene expression of EMT-related transcription factors, stemness markers, cytokine levels and angiogenic factors in both cell population was assessed. The sorted CD44+ cells showed significantly higher proliferation rate than heterogenous population. The CD44 expression was >90% in the sorted cells which was higher than the heterogenous cells. The CD44+ CSCs cells demonstrated significant increased levels of EMT-related genes TWIST1 and CDH2 (N-cadherin), CSC-related genes CD44 and CD133 (PROM1), stemness-related genes OCT4, SOX2, inflammatory cytokines IL-1ß, IL-12, IL-18 and TNF-α and angiogenic factors Angiopoietin-1, Angiopoietin-2, bFGF and VEGF while levels of epithelial gene CDH1 (E-cadherin) decreased in comparison to mixed cell population. The genetic and secretome profiling of the CD44+ CSCs could serve as diagnostic and prognostic tools in the treatment of oral cancers.

Targeted Nanoparticles for Co-delivery of 5-FU and Nitroxoline, a Cathepsin B Inhibitor, in HepG2 Cells of Hepatocellular Carcinoma

BACKGROUND

The first choice of treatment in Hepatocellular Carcinoma (HCC) is 5-fluorouracil (5-FU). Nitroxoline (NIT), a potent inhibitor of Cathepsin B, impairs tumor progression by decreased extracellular matrix degradation. The objective of the current project was designed to target nanoparticles for co-delivery of 5-FU and NIT in order to enhance the 5-FU cytotoxic effects and reduce the metastatic properties of HepG2 cells.

METHODS

5-FU and NIT were loaded in chitosan-chondroitin nanoparticles. To target the CD44 receptors of HepG2 cells, Hyaluronic Acid (HA) was conjugated to the chondroitin by adipic acid dihydrazide and the conjugation was confirmed by FTIR and 1HNMR. After physicochemical characterization and optimization of the processing variables, MTT assay was done on HepG2 and NIH3T3 cell lines to determine the cytotoxic properties of HA targeted nanoparticles. Migration of the cells was studied to compare the co-delivery of the drugs with each drug alone.

RESULTS

The optimized nanoparticles showed the particle size of 244.7±16.3nm, PDI of 0.30±0.03, drug entrapment efficiency of 46.3±5.0% for 5-FU and 75.1±0.9% for NIT. The drug release efficiency up to 8 hours was about 37.6±0.9% for 5-FU and 62.9±0.7% for NIT. The co-delivery of 5-FU and NIT in targeted nanoparticles showed significantly more cytotoxicity than the mixture of the two free drugs, non-targeted nanoparticles or each drug alone and reduced the IC50 value of 5-FU from 3.31±0.65μg/ml to 0.17±0.03μg/ml and the migration of HepG2 cells was also reduced to five-fold.

CONCLUSION

Co-delivery of 5-FU and NIT by HA targeted chitosan-chondroitin nanoparticles may be promising in HCC.

Down regulation of lactotransferrin enhanced radio-sensitivity of nasopharyngeal carcinoma

INTRODUCTION

It is reported that LTF had a radiation resistance effect, and its expression in nasopharyngeal carcinoma (NPC) was significantly down-regulated. However, the mechanism of down-regulated LTF affecting the sensitivity of radiotherapy has remained elusive.

METHODS

We re-analyzed the microarray data GSE36972 and GSE48503 to find differentially expressed genes (DEGs) in NPC cell line 5-8 F transfected with LTF or vector control, and the DEGs between radio-resistant and radio-sensitive NPC cell lines. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and protein-protein interaction network (PPI) analysis of DEGs were performed to obtain the node genes. The target genes of miR-214 were also predicted to complement the mechanism associated with radiotherapy resistance because it could directly target LTF.

RESULTS

This study identified 1190 and 1279 DEGs, respectively. GO and KEGG analysis showed that apoptotic process and proliferation, PI3K-Akt signaling pathway were significantly enriched pathways. Four nodes (DUSP1, PPARGC1A, FOS and SMARCA1) associated with LTF were screened. And 42 target genes of miR-214 were cross-linked to radiotherapy sensitivity.

CONCLUSIONS

The present study demonstrates the possible molecular mechanism that the down-regulated LTF enhances the radiosensitivity of NPC cells through interaction with DUSP1, PPARGC1A, FOS and SMARCA1, and miR-214 as its superior negative regulator may play a role in regulating the radiotherapy effect.

Development and Validation of Autophagy-Related Gene Signature and Nomogram for Predicting Survival in Oral Squamous Cell Carcinoma

Background

Autophagy, a highly conserved self-digesting process, has been deeply involved in the development and progression of oral squamous cell carcinoma (OSCC). However, the prognostic value of autophagy-related genes (ARGs) for OSCC still remains unclear. Our study set out to develop a multigene expression signature based on ARGs for individualized prognosis assessment in OSCC patients.

Methods

Based on The Cancer Genome Atlas (TCGA) database, we identified prognosis-related ARGs through univariate COX regression analysis. Then we performed the least absolute shrinkage and selection operator (LASSO) regression analysis to identify an optimal autophagy-related multigene signature with the subsequent validation in testing set, GSE41613 and GSE42743 datasets.

Results

We identified 36 prognosis-related ARGs for OSCC. Subsequently, the multigene signature based on 13 prognostic ARGs was constructed and successfully divided OSCC patients into low and high-risk groups with significantly different overall survival in TCGA training set (p < 0.0001). The autophagy signature remained as an independent prognostic factor for OSCC in univariate and multivariate Cox regression analyses. The area under the curve (AUC) values of the receiver operating characteristic (ROC) curves for 1, 3, and 5-year survival were 0.758, 0.810, 0.798, respectively. Then the gene signature was validated in TCGA testing set, GSE41613 and GSE42743 datasets. Moreover, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and single-sample gene set enrichment analysis (ssGSEA) revealed the underlying biological characteristics and signaling pathways associated with this signature in OSCC. Finally, we constructed a nomogram by combining the gene signature with multiple clinical parameters (age, gender, TNM-stage, tobacco, and alcohol history). The concordance index (C-index) and calibration plots demonstrated favorable predictive performance of our nomogram.

Conclusion

In summary, we identified and verified a 13-ARGs prognostic signature and nomogram, which provide individualized prognosis evaluation and show insight for potential therapeutic targets for OSCC.

External validation of putative biomarkers in eutopic endometrium of women with endometriosis using NanoString technology

PURPOSE

To combine different independent endometrial markers to classify the presence of endometriosis.

METHODS

Endometrial biopsies were obtained from 109 women with endometriosis as well as 110 control women. Nine candidate biomarkers independent of cycle phase were selected from the literature and NanoString was performed. We compared differentially expressed genes between groups and generated generalized linear models to find a classifier for the disease.

RESULTS

Generalized linear models correctly detected 68% of women with endometriosis (combining deep infiltrating and ovarian endometriosis). However, we were not able to distinguish between individual types of endometriosis compared to controls. From the 9 tested genes, FOS, MMP7, and MMP11 seem to be important for disease classification, and FOS was the most over-expressed gene in endometriosis.

CONCLUSION(S)

Although generalized linear models may allow identification of endometriosis, we did not obtain perfect classification with the selected gene candidates.

Inhibitory effect of microRNA-608 on lung cancer cell proliferation, migration, and invasion by targeting BRD4 through the JAK2/STAT3 pathway

Lung cancer is the leading cause of cancer-related mortality around the world. This malignancy has a 5-year survival rate of 21%, because most of the patients are diagnosed in the middle or late stage of the disease when local metastasis and tumor invasion have already progressed. Therefore, the investigation of the pathogenesis of lung cancer is an issue of crucial importance. MicroRNAs (miRNAs) seem to be involved in the evolution and development of lung cancer. MicroRNA-608 is likely to be downregulated in lung cancer tissues. Regarding this, the current study involved the determination of the fundamental mechanism of microRNA-608 in the development of lung cancer. Based on the results of quantitative reverse transcription polymerase chain reaction (RT-qPCR), the expression level of microRNA-608 was downregulated in 40 lung cancer tissues, compared to that in the adjacent normal tissues. The results of dual-luciferase reporter assay revealed that bromodomain-containing protein 4 (BRD4) was the direct target of microRNA-608. Accordingly, the lung cancer tissues had an elevated expression level of BRD4, in contrast to the adjacent normal tissues. The results of Cell Counting Kit 8 assay demonstrated that the high expression of microRNA-608 notably restrained lung cancer cell proliferation. The scratch wound and transwell assays showed that the upregulation of microRNA-608 suppressed the migration and invasion of lung cancer cells. Finally, the western blot assay showed that in the microRNA-608 mimics group, the expression levels of BRD4, p-JAK2, p-STATA3, CD44, and MMP9 were significantly decreased, compared with those in the negative control miRNA mimics group. Our results indicate that high expression of microRNA-608 inhibits the proliferation, migration, and invasion of lung cancer cells by targeting BRD4 via the JAK2/STAT3 pathway.

hnRNPK promotes gastric tumorigenesis through regulating CD44E alternative splicing

Background

The high prevalence of alternative splicing among genes implies the importance of genomic complexity in regulating normal physiological processes and diseases such as gastric cancer (GC). The standard form of stem cell marker CD44 (CD44S) and its alternatives with additional exons are reported to play important roles in multiple types of tumors, but the regulation mechanism of CD44 alternative splicing is not fully understood.

Methods

Here the expression of hnRNPK was analyzed among the Cancer Genome Atlas (TCGA) cohort of GC. The function of hnRNPK in GC cells was analyzed and its downstream targeted gene was identified by chromatin immunoprecipitation and dual luciferase report assay. Finally, effect of hnRNPK and its downstream splicing regulator on CD44 alternative splicing was investigated.

Results

The expression of hnRNPK was significantly increased in GC and its upregulation was associated with tumor stage and metastasis. Loss-of-function studies found that hnRNPK could promote GC cell proliferation, migration, and invasion. The upregulation of hnRNPK activates the expression of the splicing regulator SRSF1 by binding to the first motif upstream the start codon (- 65 to - 77 site), thereby increasing splicing activity and expression of an oncogenic CD44 isoform, CD44E (has additional variant exons 8 to 10, CD44v8-v10).

Conclusion

These findings revealed the importance of the hnRNPK-SRSF1-CD44E axis in promoting gastric tumorigenesis.

The Jun N-terminal kinases signaling pathway plays a "seesaw" role in ovarian carcinoma: a molecular aspect

Ovarian cancer is the most common gynecological malignancy that causes cancer-related deaths in women today; this being the case, developing an understanding of ovarian cancer has become one of the major driving forces behind cancer research overall. Moreover, such research over the last 20 years has shown that the Jun N-terminal kinase (JNK) signaling pathway plays an important role in regulating cell death, survival, growth and proliferation in the mitogen-activated protein kinases (MAPK) signaling pathway, an important pathway in the formation of cancer. Furthermore, the JNK signaling pathway is often regulated by an abnormal activation in human tumors and is frequently reported in the literature for its effect on the progression of ovarian cancer. Although the FDA has approved some JNK inhibitors for melanoma, the agency has not approved JNK inhibitors for ovarian cancer. However, there are some experimental data on inhibitors and activators of the JNK signaling pathway in ovarian cancer, but related clinical trials need to be further improved. Although the Jun N-terminal kinase (JNK) signaling pathway is implicated in the formation of cancer in general, research has also indicated that it has a role in suppressing cancer as well. Here, we summarize this seemingly contradictory role of the JNK signaling pathway in ovarian cancer, that ‘seesaws’ between promoting and suppressing cancer, as well as summarizing the application of several JNK pathway inhibitors in cancer in general, and ovarian cancer in particular.

Salivary Extracellular Vesicle-Associated exRNA as Cancer Biomarker

Extracellular vesicles (EVs) secreted in biological fluids contain several transcripts of the cell of origin, which may modify the functions and phenotype of proximal and distant cells. Cancer-derived EVs may promote a favorable microenvironment for cancer growth and invasion by acting on stroma and endothelial cells and may favor metastasis formation. The transcripts contained in cancer EVs may be exploited as biomarkers. Protein and extracellular RNA (exRNA) profiling in patient bio-fluids, such as blood and urine, was performed to identify molecular features with potential diagnostic and prognostic values. EVs are concentrated in saliva, and salivary EVs are particularly enriched in exRNAs. Several studies were focused on salivary EVs for the detection of biomarkers either of non-oral or oral cancers. The present paper provides an overview of the available studies on the diagnostic potential of exRNA profiling in salivary EVs.

Gab2 promotes cancer stem cell like properties and metastatic growth of ovarian cancer via downregulation of miR-200c

Scaffolding adaptor Gab2 is overexpressed in a subset of high-grade ovarian cancer. Our published work shows that Gab2 via PI3K enhances migratory behaviors and epithelial to mesenchymal transition (EMT) features of ovarian cancer cells in vitro. However, it is still unclear how Gab2/PI3K pathway reuglates EMT characteristics and whether Gab2 promotes the growth of ovarian cancer stem cell (CSC)-like population and metastatic growth. In this study, we examined the effects of Gab2 expression on CSC-like cell growth using Aldefluor and tumorshpere assays commonly used for assessing ovarian cancer cells with CSC properties. Gab2 overexpression increased the number of ALDH⁺ cells and tumorsphere formation in two different ovarian cancer cell lines OVCAR5 and OVCAR8, whereas knockdown of Gab2 decreased the number of ALDH⁺ cells and tumorsphere formation in Caov-3 cells. Furthermore, Gab2 promoted metastatic tumor growth of OVCAR5 in nude mice. Mechanistically, we uncovered that Gab2 via PI3K specifically inhibited miR-200c expression. miR-200c downregulation contributed to the Gab2-enhanced cell migratory behaviors, EMT properties, and the expansion of ALDH⁺ cells and tumorspheres. Furthermore, Gab2 promoted CD44 expression and cell migration/invasion through miR-200c downregulation. Our findings support a model that Gab2-PI3K pathway via miR-200c downregulation promotes CD44 expression, EMT characteristics, and CSC-like cell growth. Therapies involving miR-200c or targeting CD44 should help treat ovarian cancer with high Gab2 expression.

Repression of AXL expression by AP-1/JNK blockage overcomes resistance to PI3Ka therapy

AXL overexpression is a common resistance mechanism to anti-cancer therapies, including the resistance to BYL719 (Alpelisib) - the p110α isoform specific inhibitor of phosphoinositide 3-kinase (PI3K) - in esophagus and head and neck squamous cell carcinoma (ESCC, HNSCC respectively). However, the mechanisms underlying AXL overexpression in resistance to BYL719 remain elusive. Here we demonstrated that the AP-1 transcription factors, c-JUN and c-FOS, regulate AXL overexpression in HNSCC and ESCC. The expression of AXL was correlated with that of c-JUN both in HNSCC patients and in HNSCC and ESCC cell lines. Silencing of c-JUN and c-FOS expression in tumor cells downregulated AXL expression and enhanced the sensitivity of human papilloma virus positive (HPVPos) and negative (HPVNeg) tumor cells to BYL719 in vitro. Blocking of the c-JUN N-terminal kinase (JNK) using SP600125 in combination with BYL719 showed a synergistic anti-proliferative effect in vitro, which was accompanied by AXL downregulation and potent inhibition of the mTOR pathway. In vivo, the BYL719-SP600125 drug combination led to the arrest of tumor growth in cell line-derived and patient-derived xenograft models, and in syngeneic head and neck murine cancer models. Collectively, our data suggests that JNK inhibition in combination with anti-PI3K therapy is a new therapeutic strategy that should be tested in HPVPos and HPVNeg HNSCC and ESCC patients.

Yes-associated protein promotes cell migration via activating Wiskott-Aldrich syndrome protein family member 1 in oral squamous cell carcinoma

BACKGROUND

Yes-associated protein (YAP) is a candidate oncogene in various cancers including oral squamous cell carcinoma (OSCC). Our previous study demonstrated that TNF-alpha could inhibit cell proliferation and invasion by YAP phosphorylation in OSCC. However, the role of YAP in OSCC is not yet clear. The objective of the present study was to elucidate the function of YAP in promoting migration in OSCC and to explore the possible mechanism with a novel YAP inhibitor CA3.

METHODS

A total of 68 OSCC patients were enrolled, and the expression levels of YAP were investigated in tissue specimens by immunohistochemical staining. The inhibitory effects of CA3, a novel inhibitor of YAP, were demonstrated by immunofluorescence, Western blotting, and transwell assays. A human PCR motility array was performed to screen the changes in the gene expression profiles of the cells. In addition, shRNA interference, YAP re-expression, and WAVE1 overexpression plasmids were used to detect the regulatory mechanism of YAP and its relationship with cell migration.

RESULTS

Yes-associated protein nuclear expression levels were associated with metastasis and 5-year overall survival rate. CA3 exhibited potent inhibitory effects on OSCC migration. YAP knockdown significantly suppressed tumor cell migration in OSCC. These effects were rescued when YAP was re-expressed and during WAVE1 overexpression in YAP-shRNA stable cells.

CONCLUSIONS

The present study revealed that YAP was associated with cell migration and that this process was regulated by YAP/WAVE1. We also demonstrated that CA3 exhibited marked inhibitory effects on YAP expression and that it could be considered a potential therapeutic target for the treatment of OSCC.

Crosstalk between Raf-MEK-ERK and PI3K-Akt-GSK3β signaling networks promotes chemoresistance, invasion/migration and stemness via expression of CD44 variants (v4 and v6) in oral cancer

BACKGROUND

The cell-surface glycoprotein CD44 is an important oral cancer stem cell (OCSC) marker and plays significant role in oral squamous cell carcinoma (OSCC) aggressiveness, however, the regulation of CD44 is incompletely understood.

METHODS

In the present study, 145 fresh human OSCC tissue specimens, including 18 adjacent normal, 42 noninvasive (N0), 53 invasive tumor samples (N_1-3) and 32 chemo-radiation resistant samples (RCRT), were included. The expression of CD44 standard (CD44s) and variants (CD44v4, CD44v6); the activation of pERK1/2, GSK3β, NICD (Notch) pathways; the cell viability; and the MMP-9/-2 activity were assessed using RT-PCR, immunohistochemistry, Western blotting, MTT assay and gelatin zymography. OSCC cell lines, including parental (SCC9/SCC4) and Cisplatin-resistant (CisR-SCC9/-SCC4) cells, were used. Knock down of CD44v4/CD44v6 (by siRNA) or inactivation of MAPK/PI3K pathways using specific PD98059/LY294002 was achieved for in vitro analysis of chemoresistance and invasion/migration.

RESULTS

Elevated CD44 variants were associated with overall OSCC progression, chemoresistance and invasion. Positive correlations were observed, mainly between the expression of CD44v4 and the activation of ERK1/2 causing chemoresistance, whereas CD44v6 expression and inactivation of GSK3β caused invasiveness of OSCC. Cisplatin resistant, CisR-SCC9/SCC4 cell lines showed OCSC properties. Inhibition of MEK/ERK1/2 by SMI or knock down (KD) of CD44v4 by siRNA reversed cisplatin-resistance, whereas blocking the PI3K/Akt/GSK3β pathway by SMI or KD of CD44v6 isoforms by respective siRNA diminished invasion/metastasis potential.

CONCLUSION

Collectively, our results demonstrated that CD44v4 expression is more linked with ERK1/2 activation and promote cisplatin resistance, whereas CD44v6 expression is associated primarily with PI3K/Akt/GSK3β activation and driving tumor invasion/migration.

Salivary extracellular vesicle-associated miRNAs as potential biomarkers in oral squamous cell carcinoma

BACKGROUND

Several studies in the past have investigated the expression of micro RNAs (miRNAs) in saliva as potential biomarkers. Since miRNAs associated with extracellular vesicles (EVs) are known to be protected from enzymatic degradation, we evaluated whether salivary EVs from patients with oral squamous cell carcinoma (OSCC) were enriched with specific subsets of miRNAs.

METHODS

OSCC patients and controls were matched with regards to age, gender and risk factors. Total RNA was extracted from salivary EVs and the differential expression of miRNAs was evaluated by qRT-PCR array and qRT-PCR. The discrimination power of up-regulated miRNAs as biomarkers in OSCC patients versus controls was evaluated by the Receiver Operating Characteristic (ROC) curves.

RESULTS

A preliminary qRT-PCR array was performed on samples from 5 OSCC patients and 5 healthy controls whereby a subset of miRNAs were identified that were differentially expressed. On the basis of these results, a cohort of additional 16 patients and 6 controls were analyzed to further confirm the miRNAs that were up-regulated or selectively expressed in the previous pilot study. The following miRNAs: miR-302b-3p and miR-517b-3p were expressed only in EVs from OSCC patients and miR-512-3p and miR-412-3p were up-regulated in salivary EVs from OSCC patients compared to controls with the ROC curve showing a good discrimination power for OSCC diagnosis. The Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway analysis suggested the possible involvement of the miRNAs identified in pathways activated in OSCC.

CONCLUSIONS

In this work, we suggest that salivary EVs isolated by a simple charge-based precipitation technique can be exploited as a non-invasive source of miRNAs for OSCC diagnosis. Moreover, we have identified a subset of miRNAs selectively enriched in EVs of OSCC patients that could be potential biomarkers.

Notch activity mediates oestrogen-induced stromal cell invasion in endometriosis

Oestrogen has been reported to control the invasiveness of endometrial stromal cells in endometriosis. Notch signalling, a master regulator of cell invasion in tumours, is regulated by oestrogen in other diseases and hyperactivated in endometriotic stromal cells. Therefore, we hypothesized that an interaction between Notch signalling and oestrogen may exist in the regulation of endometrial stromal cell invasion, which is essential for the development of endometriosis. Western blot analysis of tissues showed that the expression levels of Notch components (JAG1 and NOTCH1) and Notch activity were markedly higher in ectopic endometria than in their eutopic and normal counterparts. Primary stromal cells obtained from normal endometria cultured with oestrogen presented significant increases in the expression of Notch components and Notch activity, the cytoplasmic and nuclear accumulation of NOTCH1 intracellular domain, the expression of matrix metallopeptidase 9 and vascular endothelial growth factor and cell invasiveness. Knockdown ofNOTCH1markedly alleviated oestrogen-induced matrix metallopeptidase 9 and vascular endothelial growth factor expression and cell invasion. ICI (an oestrogen receptor α antagonist) also blocked these oestrogenic effects. Oestrogen-responsive elements were found in the promoters ofNOTCH1andJAG1. A luciferase reporter analysis revealed that oestrogen regulated the expression of Notch components via oestrogen receptor alpha, which is bound to oestrogen-responsive elements in theJAG1andNOTCH1promoters. Collectively, our findings indicate that oestrogen engages in crosstalk with Notch signalling to regulate cell invasion in endometriosis via the activation of oestrogen receptor alpha and the enhancement of Notch activity. Notch signalling blockade may therefore be a novel therapeutic target for endometriosis.

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.

c-Fos mediates α1, 2-fucosyltransferase 1 and Lewis y expression in response to TGF-β1 in ovarian cancer

FUT1 is a key rate-limiting enzyme in the synthesis of Lewis y, a membrane-associated carbohydrate antigen. The aberrant upregulation of FUT1 and Lewis y antigen is related to proliferation, invasion and prognosis in malignant epithelial tumors. A c-Fos/activator protein-1 (AP-1) binding site was found in the FUT1 promoter. However, the mechanisms of transcriptional regulation of FUT1 remain poorly understood. TGF-β1 is positively correlated to Lewis y. In the present study, we investigated the molecular mechanism of FUT1 gene expression in response to TGF-β1. We demonstrated that c-Fos was highly expressed in 77.50% of ovarian epithelial carcinoma cases and was significantly correlated with Lewis y. Using luciferase activity and chromatin immunoprecipitation (ChIP) assay, we further revealed that c-Fos interacted with the FUT1 promoter in ovarian cancer cells and transcriptional capacity of the heterodimer formed by c-Fos and c-Jun was stronger than that of the c-Fos or c-Jun homodimers. Then, we demonstrated that TGF-β1 induced dose-dependent c-Fos expression, which was involved in TGF-β1-induced ovarian cancer cell proliferation. In addition, inhibition of MAPK activation or TGF-β1 receptor by pharmacological agents prevented TGF-β1-induced c-Fos and Lewis y expression. Silencing of c-Fos prevented TGF-β1-induced Lewis y expression. Collectively, the results of these studies demonstrated that TGF-β1 regulated FUT1 and Lewis y expression by activating the MAPK/c-Fos pathway.

Musashi-2, a novel oncoprotein promoting cervical cancer cell growth and invasion, is negatively regulated by p53-induced miR-143 and miR-107 activation

Background

Although previous studies have shown promise for targeting Musashi RNA-binding protein 2 (MSI-2) in diverse tumors, the role and mechanism of MSI-2 for cervical cancer (CC) progression and the regulation of MSI-2 expression remains unclear.

Methods

Using gene expression and bioinformatic analysis, together with gain- and loss-of-function assays, we identified MSI-2 as a novel oncogenic driver and a poor prognostic marker in CC. We explored the regulation of c-FOS by MSI-2 via RNA-immunoprecipitation and luciferase assay, and confirmed a direct inhibition of MSI-2 by miR-143/miR-107 using luciferase assay. We assessed the effect of a natural antibiotic Mithramycin A on p53, miR-143/miR-107 and MSI-2 expression in CC cells.

Results

MSI-2 mRNA is highly expressed in CC tissues and its overexpression correlates with lower overall survival. MSI-2 promotes CC cell growth, invasiveness and sphere formation through directly binding to c-FOS mRNA and by increasing c-FOS protein expression. Furthermore, miR-143/miR-107 are two tumor suppressor miRNAs that directly bind and inhibit MSI-2 expression in CC cells, and downregulation of miR-143/miR-107 associates with poor patient prognosis. Importantly, we found that p53 decreases the expression of MSI-2 through elevating miR-143/miR-107 levels, and treatment with a natural antibiotic Mithramycin A increased p53 and miR-143/miR-107 expression and reduced MSI-2 expression, resulting in the inhibition of CC cell proliferation, invasion and sphere formation.

Conclusions

These results suggest that MSI-2 plays a crucial role in promoting the aggressive phenotypes of CC cells, and restoration of miR-143/miR-107 by Mithramycin A via activation of p53 may represent a novel therapeutic approach for CC.

The Role of p16INK4a Pathway in Human Epidermal Stem Cell Self-Renewal, Aging and Cancer

The epidermis is a self-renewing tissue. The balance between proliferation and differentiation processes is tightly regulated to ensure the maintenance of the stem cell (SC) population in the epidermis during life. Aging and cancer may be considered related endpoints of accumulating damages within epidermal self-renewing compartment. p16^INK4a is a potent inhibitor of the G1/S-phase transition of the cell cycle. p16^INK4a governs the processes of SC self-renewal in several tissues and its deregulation may result in aging or tumor development. Keratinocytes are equipped with several epigenetic enzymes and transcription factors that shape the gene expression signatures of different epidermal layers and allow dynamic and coordinated expression changes to finely balance keratinocyte self-renewal and differentiation. These factors converge their activity in the basal layer to repress p16^INK4a expression, protecting cells from senescence, and preserving epidermal homeostasis and regeneration. Several stress stimuli may activate p16^INK4a expression that orchestrates cell cycle exit and senescence response. In the present review, we discuss the role of p16^INK4a regulators in human epidermal SC self-renewal, aging and cancer.

Involvement of c-Fos in the Promotion of Cancer Stem-like Cell Properties in Head and Neck Squamous Cell Carcinoma

Purpose: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Although improvements in surgical techniques, chemotherapy and radiation delivery, and supportive care have improved quality of life for patients with HNSCC, regional and distant recurrence remain common. Recent evidence suggests that cancer stem-like cells (CSC) play a significant role in recurrence and chemoresistance. We previously observed that c-Fos was highly upregulated in the HNSCC sphere-forming cells. Consequences of c-Fos upregulation for the biology of HNSCC-CSCs are poorly understood. In this study, we investigated the role of c-Fos in renewal of stemness of HNSCC and tumor growth.Experimental Design and Results: We generated stable HNSCC cell lines ectopically expressing the c-Fos gene. Exogenous expression of c-Fos in nontumorigenic MDA1386Tu cells makes these cells tumorigenic in nude mice. Furthermore, subcutaneous transplantation of c-Fos-overexpressing Cal27 cells (tumorigenic) into immunocompromised mice enhanced tumor growth as compared with parental cells. Mechanistic investigations demonstrated that c-Fos overexpression enhanced the epithelial-mesenchymal transition (EMT) state and expression of CSC markers (Nanog, c-Myc, Sox2, and Notch1). Ectopic expression of c-Fos in HNSCC cells also displays increased sphere formation. We further observed that overexpression of c-Fos increased the expression of pERK and cyclin D1 in HNSCC cells.Conclusions: Together, our results strongly suggest a novel role of c-Fos as a regulator of EMT and cancer stem cell reprogramming in HNSCC cells, which may hold potential as a CSC-directed therapeutic approach to improve HNSCC treatment. Clin Cancer Res; 23(12); 3120-8. ©2016 AACR.

Positive association between CD44 gene rs13347 C>T polymorphism and risk of cancer in Asians: a systemic review and meta-analysis

Background

Cluster of differentiation 44 (CD44) is an important surface marker of cancer stem cells in a variety of tumors. A number of previous studies have been conducted to investigate the association between CD44 gene rs13347 C>T polymorphism and cancer risk in humans; nevertheless, the results remain controversial. We therefore performed this meta-analysis to confirm the role of this polymorphism in susceptibility to human cancer.

Materials and methods

The studies published up to December 2015 were searched in PubMed, Web of Science, and China National Knowledge Infrastructure databases. Twelve eligible case–control studies were identified, involving a total of 6,982 cases and 7,430 controls. Pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were calculated using a fixed or random-effect model to estimate the strength of the association.

Results

The results of the overall analyses indicated that CD44 gene rs13347 polymorphism was significantly associated with cancer risk in Asians (CT vs CC: OR =1.35, 95% CI =1.12–1.62; TT vs CC: OR =1.99, 95% CI =1.52–2.60; TT + CT vs CC: OR =1.41, 95% CI =1.16–1.71; and TT vs CC + CT: OR =1.74, 95% CI =1.41–2.14), especially in Chinese population (CT vs CC: OR =1.42, 95% CI =1.16–1.75; TT vs CC: OR =2.13, 95% CI =1.58–2.86; TT + CT vs CC: OR =1.50, 95% CI =1.21–1.87; and TT vs CC + CT: OR =1.80, 95% CI =1.43–2.26). In stratified analyses by cancer types, there was evidence for an association between this polymorphism and nasopharyngeal cancer and breast cancer, respectively.

Conclusion

The results of this meta-analysis suggest that the CD44 gene rs13347 C>T polymorphism is associated with elevated risk of human cancer in Asians, especially in Chinese population. Further well-designed studies on a larger population covering other ethnicities should be carried out to validate our results.

Association of CD44 Gene Polymorphism with Survival of NSCLC and Risk of Bone Metastasis

Background

Previous studies have reported CD44 expression influenced the development and progression of tumors. The aim of this study was to investigate whether single-nucleotide polymorphisms (SNPs) of the CD44 gene are associated with survival of non-small cell lung cancer (NSCLC) and occurrence rate of bone metastasis.

Material/Methods

A total of 234 patients with NSCLC between 2003 and 2010 were enrolled in this study and 468 healthy persons were used as controls. Two polymorphisms, rs13347 and rs187115, in the CD44 gene were genotyped using DNA from blood lymphocytes. For statistical analysis we used the chi-square test, Fisher’s exact test, Kaplan-Meier method, and log-rank test.

Results

CD44 gene rs13347 polymorphism was not associated with NSCLC risk. For rs187115, the association with NSCLC risk was observed (P<0.001). Allele G carriers had significantly higher occurrence rates of bone metastasis (OR=0.4, 95%CI: 0.20–0.64, P<0.001) and more advanced tumor stage (OR=2.6, 95%CI: 1.50–4.45, P=0.001) compared to carriers of allele A. The survival rates for patients with AA genotype were significantly higher than for patients with the AG+GG genotypes (P<0.001). In multivariate analysis of survival in NSCLC patients, significant predictors were CD44 gene (AG+GG) (RR=0.48, 95%CI: 0.34–0.68, P<0.001), tumor stage (RR=0.45, 95%CI: 0. 0.31–0.65, P<0.001), and bone metastasis (RR=1.52, 95%CI: 1.05–2.21, P=0.027).

Conclusions

CD44 gene rs187115 polymorphism is a potential predictive marker of survival in NSCLC patients, and is significantly correlated with bone metastasis and tumor stage.