Blocking PI3K/Akt signaling attenuates metastasis of nasopharyngeal carcinoma cells through induction of mesenchymal-epithelial reverting transition

Chitinase 3 like-1 activates the Akt pathway, inducing NF-κB-dependent release of pro-inflammatory cytokines and promoting the proliferative ability in nasopharyngeal carcinoma cells

BACKGROUND

Chitinase 3 like-1 (CHI3L1) has been reported to function as an oncogene in many types of cancer. However, the biological function of CHI3L1 in nasopharyngeal carcinoma (NPC) remains unknown.

METHODS

Differentially expressed genes (DEGs) in NPC tissues in GSE64634 and GSE12452 were downloaded from Gene Expression Omnibus (GEO). CHI3L1, interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) mRNA expression was examined by qRT-PCR. Cell proliferation was evaluated by CCK-8 and EdU incorporation assays. Western blot analysis was used to measure the changes of CHI3L1, nuclear factor-κappaB (NF-κB), and protein kinase B (Akt) pathways. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analyses were performed using DAVID database.

RESULTS

We identified 3 overlapping DEGs using Draw Venn diagram, among which CHI3L1 was chosen for the following analyses. CHI3L1 was upregulated in NPC tissues and cells. CHI3L1 silencing suppressed inflammatory response by inactivating the NF-κB pathway and inhibited cell proliferation in NPC cells. On the contrary, CHI3L1 overexpression induced inflammatory response by activating the NF-κB pathway and promoted cell proliferation in NPC cells. According to GO and KEGG analyses, CHI3L1 positive regulates Akt signaling and is enriched in the PI3K-Akt pathway. CHI3L1 knockdown inhibited the Akt pathway, and CHI3L1 overexpression activated the Akt pathway in NPC cells. Akt overexpression abolished the effects of CHI3L1 knockdown on inflammatory response, NF-κB pathway, and proliferation in NPC cells. On the contrary, Akt knockdown abolished the effects of CHI3L1 overexpression on inflammatory response, NF-κB pathway, and proliferation in NPC cells.

CONCLUSION

CHI3L1 knockdown inhibited NF-κB-dependent inflammatory response and promoting proliferation in NPC cells by inactivating the Akt pathway.

Unleashing the pathological imprinting of cancer in autoimmunity: Is ZEB1 the answer?

The intriguing scientific relationship between autoimmunity and cancer immunology have been traditionally indulged to throw spotlight on novel pathological targets. Understandably, these "slowly killing" diseases are on the opposite ends of the immune spectrum. However, the immune regulatory mechanisms between autoimmunity and cancer are not always contradictory and sometimes mirror each other based on disease stage, location, and timepoint. Moreover, the blockade of immune checkpoint molecules or signalling pathways that unleashes the immune response against cancer is being leveraged to preserve self-tolerance and treat many autoimmune disorders. Therefore, understanding the common crucial factors involved in cancer is of paramount importance to paint the autoimmune disease spectrum and validate novel drug candidates. In the current review, we will broadly describe how ZEB1, or Zinc-finger E-box Binding Homeobox 1, reinforces immune exhaustion in cancer or contributes to loss of self-tolerance in auto-immune conditions. We made an effort to exchange information about the molecular pathways and pathological responses (immune regulation, cell proliferation, senescence, autophagy, hypoxia, and circadian rhythm) that can be regulated by ZEB1 in the context of autoimmunity. This will help untwine the intricate and closely postured pathogenesis of ZEB1, that is less explored from the perspective of autoimmunity than its counterpart, cancer. This review will further consider several approaches for targeting ZEB1 in autoimmunity.

Irisin/FNDC5 inhibits the epithelial-mesenchymal transition of epithelial ovarian cancer cells via the PI3K/Akt pathway

PURPOSE

This study explored the role of irisin/fibronectin type III domain-containing protein 5 (FNDC5) in epithelial ovarian cancer and investigated its underlying mechanisms.

METHODS

Immunohistochemistry was performed to analyze the expression of irisin/FNDC5 in epithelial ovarian cancer and normal ovarian tissues. Cell Counting Kit-8, transwell, and wound-healing assays were performed to examine the effect of irisin on the viability, migration, and invasion of ovarian cancer cells, respectively. Western blotting was used to detect the changes of epithelial-mesenchymal transition (EMT)-related proteins and phosphatidylinositol 3-kinase (PI3K)/Akt pathway proteins. Ovarian cancer cells were treated in vitro with the PI3K agonist (740Y-P) in combination with irisin to explore the mechanism of irisin in ovarian cancer.

RESULTS

The expression of irisin/FNDC5 in epithelial ovarian cancer tissue was significantly higher than that in normal ovarian tissues, and the expression in late stage patients with lymph node metastasis was lower than that in early stage patients without metastasis. Irisin inhibited the proliferation, invasion, and migration of epithelial ovarian cancer cells, down-regulated phosphorylated Akt, and inhibited EMT progression. The PI3K agonist, 740Y-P, partially reversed the effects of irisin on the invasion, migration, and EMT of ovarian cancer cells.

CONCLUSION

These findings show that irisin/FNDC5 was highly expressed in ovarian cancer tissues, which may regulate the EMT through the PI3K/Akt signaling pathway and inhibit the proliferation, invasion, and migration of epithelial ovarian cancer.

Circular RNA circ_0008450 regulates the proliferation, migration, invasion, apoptosis and chemosensitivity of CDDP-resistant nasopharyngeal carcinoma cells by the miR-338-3p/SMAD5 axis

Circular RNAs have recently been implicated in the tumorigenesis and chemoresistance of nasopharyngeal carcinoma (NPC). In this report, we identified the precise action of circ_0008450 in NPC progression and cisplatin (CDDP) resistance. The levels of circ_0008450, microRNA (miR)-338-3p and SMAD family member 5 (SMAD5) were gauged by quantitative real-time PCR or western blot. Cell proliferation and IC50 value for CDDP were detected by the Cell Counting Kit-8 assay. Cell colony formation, cell cycle progression, apoptosis, migration and invasion were assessed by colony formation, flow cytometry and transwell assays, respectively. Targeted relationships among circ_0008450, miR-338-3p and SMAD5 were determined by dual-luciferase reporter and RNA immunoprecipitation assays. Tumor models were assayed to evaluate the role of circ_0008450 in tumor growth. Our data indicated that up-regulated circ_0008450 was correlated with NPC CDDP resistance. Moreover, the knockdown of circ_0008450 suppressed cell proliferation, migration, invasion, and promoted apoptosis and CDDP sensitivity in vitro, as well as weakened tumor growth in vivo. Mechanistically, circ_0008450 directly bound to miR-338-3p, and the regulatory effects of circ_0008450 on cell malignant behaviors and CDDP sensitivity were mediated by miR-338-3p in vitro. SMAD5 was a direct target of miR-338-3p and circ_0008450 mediated SMAD5 expression through miR-338-3p. Furthermore, the enforced level of miR-338-3p regulated cell malignant behaviors and CDDP sensitivity in vitro via down-regulating SMAD5. Additionally, the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway was modulated by the circ_0008450/miR-338-3p axis in the two CDDP-resistant NPC cell lines. Our current study suggested that circ_0008450 modulated the malignant behaviors and drug sensitivity of CDDP-resistant NPC cells at least in part by targeting the miR-338-3p/SMAD5 axis, providing potential targets for improving the treatment of chemoresistant NPC.

Advances in pathogenesis and precision medicine for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a squamous carcinoma with apparent geographical and racial distribution, mostly prevalent in East and Southeast Asia, particularly concentrated in southern China. The epidemiological trend over the past decades has suggested a substantial reduction in the incidence rate and mortality rate due to NPC. These results may reflect changes in lifestyle and environment, and more importantly, a deeper comprehension of the pathogenic mechanism of NPC, leading to much progress in the preventing, screening, and treating for this cancer. Herein, we present the recent advances on the key signal pathways involved in pathogenesis of NPC, the mechanism of Epstein‐Barr virus (EBV) entry into the cell, and the progress of EBV vaccine and screening biomarkers. We will also discuss in depth the development of various therapeutic approaches including radiotherapy, chemotherapy, surgery, targeted therapy, and immunotherapy. These research advancements have led to a new era of precision medicine in NPC.

CKB inhibits epithelial-mesenchymal transition and prostate cancer progression by sequestering and inhibiting AKT activation

Epithelial-mesenchymal transition (EMT) contributes to tumor invasion, metastasis and drug resistance. AKT activation is key in a number of cellular processes. While many positive regulators for either EMT or AKT activation have been reported, few negative regulators are established. Through kinase cDNA screen, we identified brain-type creatine kinase (CKB or BCK) as a potent suppressor for both. As a ubiquitously expressed kinase in normal tissues, CKB is significantly downregulated in several solid cancer types. Lower CKB expression is significantly associated with worse prognosis. Phenotypically, CKB overexpression suppresses, while its silencing promotes, EMT and cell migration, xenograft tumor growth and metastasis of prostate cancer cells. AKT activation is one of the most prominent signaling events upon CKB silencing in prostate cancer cells, which is in line with prostate cancer TCGA data. EMT enhanced by CKB silencing is abolished by AKT inhibition. Mechanistically, CKB interacts with AKT and sequestrates it from activation by mTOR. We further elucidated that an 84aa fragment at C-terminus of CKB protein interacts with AKT's PH domain. Ectopic expression of the 84aa CKB fragment inhibits AKT activation, EMT and cell proliferation. Interestingly, molecular dynamics simulation on crystal structures of AKT and CKB independently demonstrates that AKT's PH domain and CKB's 84aa fragment establish their major interaction interface. In summary, we have discovered CKB as a negative regulator of EMT and AKT activation, revealing a new mode of their regulation . We have also demonstrated that CKB downregulation is a poor prognosticator, which is sufficient to promote prostate cancer progression.

Influences of S100A8 and S100A9 on Proliferation of Nasopharyngeal Carcinoma Cells through PI3K/Akt Signaling Pathway

Objective

To investigate the effects of S100A8 and S100A9 on proliferation in nasopharyngeal carcinoma cells and the regulatory effects of PI3K/Akt signaling pathway.

Methods

Nasopharyngeal carcinoma cells (CNE1) were cultured and randomly divided into three groups: control group, S100A8/S100A9 overexpression group, and siRNA S100A8/S100A9 group. CCK-8 method was used to detect the effect of S100A8 and S100A9 on the viability of nasopharyngeal carcinoma cells. The effects of S100A8 and S100A9 on the colony forming ability of nasopharyngeal carcinoma cells were detected by colony forming assay. The effects of S100A8 and S100A9 on the proliferation of nasopharyngeal carcinoma cells were detected by EdU staining. The mRNA levels of PI3K and Akt were detected by RT-PCR. The expression levels of PI3K and Akt in NPC cells were detected by Western blot. Wortmannin, an inhibitor of PI3K/Akt pathway, was used to inhibit the activation of PI3K/Akt pathway.

Results

Compared with the control group, the cell viability, the number of plate clones, the positive rate of EdU staining, and the mRNA and protein levels of PI3K and Akt were increased in the overexpression group. Compared with the control group, the cell viability, the number of plate clones, the positive rate of EdU staining, and the mRNA and protein levels of PI3K and Akt were decreased in the siRNA group. After inhibiting the activation of PI3K/Akt pathway, the viability of NPC cells in the overexpression group decreased significantly at 48 h and 72 h, while that in the siRNA group increased significantly.

Conclusion

SiRNA S100A8 and S100A9 could inhibit the proliferation of nasopharyngeal carcinoma cells, and the underlying mechanism may be related to the inhibition of PI3K/Akt signaling pathway.

Cell Proliferation and Apoptosis-Related Genes Affect the Development of Human Nasopharyngeal Carcinoma Through PI3K/AKT Signaling Pathway

Nasopharyngeal carcinoma (NPC) is one of the common malignant tumors in China, which occurs on the top and sidewalls of the nasopharyngeal cavity. The incidence of malignant tumors of the ear, nose and throat is the highest. However, little is known about the growth of the cells. Therefore, this study constructed a multi-regulator-driven NPC cell growth-related module, aiming to explore the mechanism of functional pathways regulating the proliferation of NPC cells in an all-round way. Firstly, differential expression analysis, co-expression analysis, enrichment analysis and connectivity analysis were synthesized to identify the intrinsic genes of expression disorder module. Subsequently, we analyzed the module by crosstalk, and observed the interaction between modules intuitively. Finally, based on hypergeometric test, the significance of multi-regulators on the regulation of potential modules is calculated. We obtained 17 cell growth-related expression disorder modules by 2148 gene modules focusing. These modules are mainly involved in the growth cycle of NPC cells, including cell proliferation, migration and apoptosis. At the same time, they mainly affect the proliferation and apoptosis of NPC cells through PI3K-AKT signaling pathway, NF-kappa B signaling pathway and Wnt signaling pathway. Based on the growth-related modules of NPC cells, we have obtained a series of non-coding RNAs (ncRNAs) including microRNA-92a-3p, microRNA-19a-3p and microRNA-130a-3p, play an important role in regulating the growth of NPC cells. Similarly, we also predicted transcription factors (involving E2F1, NFKB1, SP1, etc.) that may play a key role in cell growth-related modules. This study is based on cell growth-related expression disorder module to explore the regulatory role of its functional pathway on cell proliferation mechanism, which will help researchers to have a deeper understanding of the potential pathogenesis of NPC.

Crosstalk between endothelial cell-specific calpain inhibition and the endothelial-mesenchymal transition via the HSP90/Akt signaling pathway

HYPOTHESIS

The role of non-cardiomyocytes in cardiac remodeling and fibrosis has not been totally understood until now. This study investigated if endothelial cell (EC)-specific calpain participates in myocardial endothelial injury via the endothelial- mesenchymal transition (EndMT) and in cardiac fibroblasts during cell proliferation, thereby contributing to cardiac fibrosis eventually.

METHODS

in vitro cultured mouse cardiac ECs were induced with transforming growth factor (TGF)-β1 (10 ng/ml) and calpain inhibitor III (20 μM) or Akt inhibitor (LY294002, 20 μM). Isolated cardiac fibroblasts were induced by TGF-β1 and an HSP90 inhibitor (17AAG, 20 μM), and EndMT were analysed. Capn4-knockout (KO) specific to ECs of mice was generated. We induced the pathological process mimicking cardiac hypertrophy and fibrosis in both Capn4-KO mice and their wild-type littermates. The histological analysis was used to measure cardiomyocyte size and collagen contained in the heart. The immunofluorescence analysis was performed to demonstrate that the ECs went through the EndMT, transforming mesenchymal cells into fibroblasts and myofibroblasts.

RESULTS

Capn4 deletion specific to ECs abrogated activity of both calpain 1 and calpain 2 in ECs, lowered the volume of cardiac collagen and cardiomyocytes size, and ameliorated myocardial dysfunction in the isoproterenol-treated cardiac fibrosis model. An ex vivo analysis of cardiomyocytes by Evans Blue staining revealed that isoproterenol increased cell death compared with the control, and Capn4-KO alleviated this result. Inhibiting calpain in cultured cardiac microvascular endothelial cells (MCECs) reversed the EndMT process, which was induced by TGF-β1. Overexpression of calpastatin decreased the pathological EndMT process, showing that the cultured MCECs have more mesenchymal markers, such as α-smooth muscle actin (SMA), and fewer endothelial markers, such as VE-cadherin. Activating calpain elevated phosphorylated Akt in mice cultured ECs, and inhibiting calpain decreased phosphorylated Akt. Upregulation of phosphorylated Akt by calpain promoted the EndMT, whereas inhibiting calpain switched on the protective mechanism during the EndMT via the heat shock protein (HSP)90/Akt signaling way in cultured ECs.

CONCLUSIONS

This study demonstrated a vital role of calpain in ECs for inducing myocardiocyte hypertrophy, cell death and the EndMT via the HSP90/Akt signaling pathway, thereby promoting cardiac fibrosis. The results indicate that inhibiting ECs calpain is a novel therapeutic target to retard cardiac fibrosis and has positive effects on heart failure.

Inhibition of PTEN Gene Expression by Small Interfering RNA on PI3K/Akt/FoxO3a Signaling Pathway in Human Nasopharyngeal Carcinoma

The objective of this article is to study the effect of inhibiting phosphatase and tensin homolog deleted chromatosome 10 gene on phosphoinositide 3-kinase/protein kinase B (Akt)/Forkhead homeobox O3a signaling pathway in human nasopharyngeal carcinoma HK-1 cells. Nasopharyngeal carcinoma HK-1 cell lines were divided into PTEN gene interference group (siPTEN), nonspecific small interfering RNA group (siNC), empty vector group (Vector), and no transfection control group (Normal). The mRNA and protein expression levels of PTEN, PI3K, p-Akt, and FoxO3a were detected by real-time fluorescence quantitative polymerase chain reaction and Western blot. Immunofluorescence was used to detect the subcellular localization of PTEN, PI3K, p-Akt, and FoxO3a in HK-1 cells. The proliferation of HK-1 cells was detected by MTT assay, and the apoptosis of HK-1 cells was detected by flow cytometry. Compared with the siNC group, the expression levels of PTEN, FoxO3a messenger RNA, and protein in the siPTEN group were significantly decreased (P < .05), while the expression levels of PI3K, p-Akt messenger RNA, and protein were significantly increased (P < .05). The growth rate of HK-1 cells in the siPTEN group was significantly higher than the siNC group (P < .05), while the apoptosis rate was significantly lower than that of the siNC group (P < .05). Small interfering RNA can inhibit the expression of PTEN in HK-1 cells, and PTEN can participate in the development of NPC by affecting PI3K/Akt/FoxO3a signaling pathway.

RETRACTED: Endogenous production of C-C motif chemokine ligand 2 by nasopharyngeal carcinoma cells drives radioresistance-associated metastasis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Following the publication of the above article, the Editor was notified by a concerned reader that the authors supplied duplicated images. Specifically, overlap in Figures 1C, 4A, 4B, 4D, and 5C. These concerns were also reported at PubPeer https://pubpeer.com/publications/CAC11E726E1C3E261A1F8BB90FF173. After review, the Editor found that duplication did occur and therefore the decision was made to retract the article. After re-examination of the entire paper, raw data and lab records, the authors have found that “pictures between different experiments were carelessly mixed. We want to apologize for all the inconvenience it caused to the editorial board, and to all our peers and to all the readers of our paper.”

Comprehensive analysis of key genes associated with ceRNA networks in nasopharyngeal carcinoma based on bioinformatics analysis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with high morbidity rates in the east and southeast Asia. The molecular mechanisms of NPC remain largely unknown. We explored the pathogenesis, potential biomarkers, and prognostic indicators of NPC.

METHODS

We analyzed mRNAs, long non-coding RNAs (lncRNAs), and microRNAs (miRNAs) in the whole transcriptome sequencing dataset of our hospital (five normal tissues vs. five NPC tissues) and six microarray datasets (62 normal tissues vs. 334 NPC tissues) downloaded from the Gene Expression Omnibus (GSE12452, GSE13597, GSE95166, GSE126683, and GSE70970, GSE43039). Differential expression analyses, gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) analysis, and gene set enrichment analysis (GSEA) were conducted. The lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) networks were constructed using the miRanda and TargetScan database, and a protein-protein interaction (PPI) network of differentially expressed genes (DEGs) was built using Search Tool for the Retrieval of Interacting Genes (STRING) software. Hub genes were identified using Molecular Complex Detection (MCODE), NetworkAnalyzer, and CytoHubba.

RESULTS

We identified 61 mRNAs, 14miRNAs, and 10 lncRNAs as shared DEGs related to NPC in seven datasets. Changes in NPC were enriched in the chromosomal region, sister chromatid segregation, and nuclear chromosome segregation. GSEA indicated that the mitogen-activated protein kinase (MAPK) pathway, phosphatidylinositol-3 OH kinase/protein kinase B (PI3K-Akt) pathway, apoptotic pathway, and tumor necrosis factor (TNF) were involved in the initiation and development of NPC. Finally, 20 hub genes were screened out via the PPI network.

CONCLUSIONS

Several DEGs and their biological processes, pathways, and interrelations were found in our current study by bioinformatics analyses. Our findings may offer insights into the biological mechanisms underlying NPC and identify potential therapeutic targets for NPC.

PNCK depletion inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cells in vitro and in vivo

Purpose: Recent studies indicate that pregnancy upregulated non-ubiquitous calmodulin kinase (PNCK) is significantly up-regulated in breast and renal carcinomas. However, the expression profile and its biological relevance of PNCK in nasopharyngeal carcinoma (NPC) have not been elucidated.

Methods: The expression level of PNCK was detected in specimens of NPC (n=10) and normal tissues (n=10) by real-time PCR and immunohistochemistry. Celigo Cell Counting and MTT assay were used to measure cell viability. Apoptosis was detected by flow cytometric analysis and caspases 3/7 activity assay. Real-time PCR and Western blotting were performed to evaluate the expression of PNCK. The bioluminescence imaging was used to evaluate the effects of PNCK knockdown on tumor growth using a xenograft animal model. The global gene expression profile was determined in wild type and PNCK-depleted CNE-2 cells via transcriptomics analysis. For mechanical investigation, the changes of PI3K/AKT/mTOR signaling pathway were detected by Western blotting.

Results: The mRNA and protein levels of PNCK were increased in human NPC samples. In vitro experiments showed that shRNA or CRISPR-Cas9 mediated silencing of PNCK inhibited proliferation and induced apoptosis in NPC cells. In addition, in vivo assay revealed that knockdown of PNCK suppressed tumor growth. Consistently, a significant reduction of tumor bioluminescence in mice inoculated with PNCK-knockdown cells compared to that of control cells. In gene expression, the transcriptomics analysis revealed that there were 589 upregulated genes and 589 downregulated genes in PNCK-knockdown cells. Ingenuity Pathway Analysis (IPA) identified significant changes of PI3K/AKT/mTOR signaling pathway in PNCK-knockdown cells. Furthermore, western blot analysis revealed that interference with PNCK reduced the phosphorylation levels of PI3K, AKT and mTOR in CNE-2 cells.

Conclusion: This study for the first time demonstrates that knockdown of PNCK could suppress growth and induce apoptosis of NPC cells both in vitro and in vivo by regulating PI3K/AKT/mTOR signaling pathway. These findings suggest that PNCK might be a novel therapeutic target for NPC treatment.

[Quantitative proteomics and differential signal enrichment in nasopharyngeal carcinoma cells with or without SETD2 gene knockout]

OBJECTIVE

To analyze the effects of alterations in the expressions of methyltransferase SETD2 on protein expression profiles in human nasopharyngeal carcinoma (NPC) cells and enrich the differential signaling pathways.

METHODS

The total protein was extracted from SETD2-knockout cell line CNE1^SETD2-KO and the wild-type cell line CNE1^WT, and the differentially expressed proteins were screened by tandem mass tag (TMT) labeled protein quantification technique and tandem mass spectrometry. GO analysis was used to annotate and enrich the differentially expressed proteins, and the KEGG database was used to enrich and analyze the pathways of the differential proteins.

RESULTS

With a fold change (FC)≥1.2 and P < 0.05 as the screening standard, 2049 differentially expressed proteins were identified in CNE1^SETD2-KO cells, among which 904 were up-regulated and 1145 were down-regulated. GO functional annotation results indicated that SETD2 knockout caused characteristic changes in multiple biological processes (cell processes and regulation, cell movement, metabolic processes, and biosynthesis of cellular components), molecular functions (catalytic activity and molecular binding, transcription factor activity), and cellular components (cell membrane, organelle, macromolecular complex). KEGG analysis showed that the differentially expressed proteins were involved in an array of signaling pathways closely related to tumors, including MAPK, PI3K-Akt, Ras, Rap1, mTOR, Hippo, HIF-1, Wnt, AMPK, FoxO, ErbB, P53 and JAK-STAT.

CONCLUSIONS

SETD2 knockout significantly changes the protein expression characteristics of NPC cells and affects a number of signal pathways closely related to tumors. The results provide evidence for investigation of the pathogenesis and therapeutic target screening of NPC.

microRNA-613 exerts anti-angiogenic effect on nasopharyngeal carcinoma cells through inactivating the AKT signaling pathway by down-regulating FN1

Background: Nasopharyngeal carcinoma (NPC) is a disease highly sensitive to radiotherapy with the unclear etiology. However, the specific effects of microRNA-613 (miR-613) on NPC still remain elusive. Therefore, the present study probes into the underlying mechanism of miR-613 in NPC via AKT signaling pathway by regulating Fibronectin 1 (FN1).

Methods: First, microarray analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs associated with NPC. Next, miR-613 and FN1 expression in NPC cells was determined, followed by verification of target relationship between miR-613 and FN1. With NPC cells exposed to miR-613 mimic, si-FN1 and LY294002 (inhibitor of AKT signaling pathway), the regulatory effects of miR-613 on proliferation, apoptosis, invasion, migration and angiogenesis of NPC cells were detected with ratio of B-cell lymphoma 2/Bcl-2-associated X protein (Bcl-2/Bax), Cleaved-caspase3, matrix metallopeptidase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), and cell adhesion molecule-1 (CD31) expression measured. Then, tumorigenesis and MVD were determined after Xenograft in nude mice.

Results: FN1 modulated by miR-613 was critical for NPC via the AKT signaling pathway. NPC cells exhibited down-regulated miR-613 and up-regulated FN1. Besides, miR-613 was verified to target FN1. Moreover, overexpressed miR-613, silenced FN1 or LY294002 treatment suppressed proliferation, invasion, migration, and angiogenesis in NPC cells, which was indicated by reduced expression of AKT, mTOR, MMP-2, MMP-9, VEGF, and CD31 as well as decreased ratio of Bcl-2/Bax and increased expression of Cleaved-caspase3. Furthermore, cell apoptosis was promoted and tumorigenesis and MVD in nude mice were inhibited with overexpression of miR-613, silenced FN1 or LY294002 treatment.

Conclusion: Taken together, miR-613 inhibits angiogenesis in NPC cells through inactivating FN1-dependent AKT signaling pathway.

Short-term stimulation with histone deacetylase inhibitor trichostatin a induces epithelial-mesenchymal transition in nasopharyngeal carcinoma cells without increasing cell invasion ability

Background

Epithelial-mesenchymal transition (EMT) may be one of the reasons for the failure in some clinical trials regarding histone deacetylase inhibitors (HDACIs)-treated solid tumors. We investigated the effects of a pan-HDACI trichostatin A (TSA) on the proliferation and EMT of nasopharyngeal carcinoma (NPC) cells.

Methods

Poorly-differentiated NPC cell line CNE2 and undifferentiated C666–1 were treated with various concentrations of TSA, the cell viability was assessed by CCK-8 assay, the morphology was photographed, and the mRNA level of HDACs was assessed by semiquantitative PCR. After determination the cell cycle distributions, cells were subjected to western blotting analysis of cell cycle and EMT-associated genes expression. And the changes in migration ability were assessed by transwell migration assay and scratch wound healing assay. Finally, histone deacetylases activator ITSA-1 was used to assess the reverse of TSA-induced changes in NPC cells.

Results

TSA inhibited the proliferation of CNE2 and C666–1 cells in a concentration-dependent manner and arrested the cell cycle at G1 phases. TSA reduced PCNA, cyclin D1, cyclin E1, CDK2, p16 and p21 expressions and stimulated CDK6 levels. TSA stimulation for 48 h could effectively induce the EMT in CNE2 and C666–1 cells, which showed an increase of spindle-like cells and promoted expression of Vimentin and Snail1 expression in a concentration-dependent manner. Surprisingly, this short period of TSA treatment that induced EMT also impeded the migration ability of CNE2 and C666–1 cells. Interestingly, ITSA-1 rescued TSA-impeded CNE2 and C666–1 cells’ proliferation, migration and HDACs expression, also re-induced the cells to turn into epithelial cell phenotypes.

Conclusions

These results indicate that short-term stimulation of TSA effectively inhibits cell proliferation and induce EMT-like changes in NPC cells but not increase its invasion ability.

Expression of vimentin in nasopharyngeal carcinoma and its possible molecular mechanism: A study based on immunohistochemistry and bioinformatics analysis

BACKGROUND

Although previous researchers have analyzed the expression level of vimentin in nasopharyngeal carcinoma (NPC), the sample size of each study was too small, and there was no further in-depth study utilizing microarray and RNA-sequencing data. More importantly, the role and molecular mechanism of vimentin in NPC have not yet been addressed comprehensively. Accordingly, the aim of the present research was to conduct a full exploration of the clinical significance of vimentin in NPC in a large sample size.

MATERIALS AND METHODS

Immunohistochemistry was used to test the expression of vimentin in clinical samples. Data from relevant microarray and RNA-sequencing datasets were screened and extracted to explore the clinical role of vimentin in NPC. Subsequently, vimentin-related signaling pathways were investigated via in-silico approaches.

RESULTS

The clinical immunohistochemistry detection showed the positive expression ratio of vimentin was 24.6% (14/57) of the NPC specimens, whereas vimentin expression was negative in nasopharyngitis (NPG) tissues (0/20, P = 0.016). The mRNA and protein levels of vimentin were both remarkably up-regulated in NPC based on 196 and 1566 cases, respectively. The protein level of vimentin was also a risky factor for the prognosis prediction of NPC with the hazard ratios (HR) being 3.831. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses, the localization of vimentin was in both the cytoplasm and the cytoskeleton, and vimentin was involved in the regulation of molecular function, the execution phase of apoptosis, and the regulation of cellular component organization.

CONCLUSION

The high expression of vimentin plays a pivotal role in the development and poor progression of NPC, which indicates that vimentin may be an effective predictive indicator for NPC.

Epstein-Barr virus-encoded LMP1 regulated Pim1 kinase expression promotes nasopharyngeal carcinoma cells proliferation

Background

Epstein–Barr virus-encoded LMP1 plays a critical role in the carcinogenesis of nasopharyngeal carcinoma (NPC), but the mechanism remains elusive. We aimed to analyze the expression and clinical pathological significance of provirus integration site for Moloney murine leukemia virus 1 (Pim1) in clinical NPC, and to elucidate the effect of LMP1 on Pim1 expression and its mechanism.

Methods

Immunohistochemical staining was used to detect the expression of Pim1 in clinical NPC tissues and control nasopharyngeal chronic inflammation (NPI) tissues, and the correlation between Pim1 and clinical parameters of NPC patients was analyzed. The LMP1 stable expression cell line CNE1-LMP1-OV was constructed through infecting the well-differentiated nasopharyngeal carcinoma cells CNE1 with LMP1 overexpressing lentivirus. Then the in vivo experiments were conducted.

Results

Among 89 NPC patients, 48 cases (53.93%) were positive for Pim1, while only one case was Pim1 positive in 15 NPI controls (6.67%). Pim1 expression was not correlated with gender, age, smoking status and clinical classification of NPC patients, but positively correlated with T, N and M classification. CNE1-LMP1-OV cell line was successfully established, which displayed a higher cell proliferation ability and Pim1 expression. NF-κB inhibitor PDTC, PKC inhibitor GF109203X and STAT3 inhibitor Stattic significantly attenuated LMP1-induced Pim1 expression, and while AP-1 inhibitor SR11302 showed no inhibitory effect. Interestingly, Pim1 inhibitor quercetagetin significantly inhibited the proliferation of CNE1-LMP1-OV cells.

Conclusion

LMP1 mediates Pim1 expression through NF-κB, PKC and STAT3 signaling, which promotes the proliferation of NPC cells and participate in the clinical progression of NPC.

ZnSO4 rescued vimentin from collapse in DBP-exposed Sertoli cells by attenuating ER stress and apoptosis

Sertoli cells (SCs) provide physical and nutritional support for spermatogenesis. Dibutyl phthalate (DBP) is a plasticizer that has male reproductive toxicity. The collapse of vimentin in DBP-exposed SCs is thought to induce the sloughing of spermatocytes from seminiferous tubules. In this study, we explored methods to rescue vimentin from collapse in DBP-exposed SCs. DBP not only induced the hyperphosphorylation of vimentin but also triggered endoplasmic reticulum (ER) stress and apoptosis in SCs. Treatment with BAPTA-AM, an antagonist of Ca²⁺, significantly decreased the level of phosphorylated vimentin, while LY294002, an inhibitor of Akt1, did not. ER stress and apoptosis remained at high levels, and the distribution of vimentin was not improved. ZnSO₄ treatment did not decrease the level of phosphorylated vimentin. However, after treatment, ER stress and apoptosis were obviously inhibited, and the distribution of vimentin was reconverted. These results indicated that ZnSO₄ could alleviate the collapse of vimentin by attenuating ER stress and apoptosis. This study suggested that an appropriate zinc supply might be a choice to alleviate DBP-induced adverse reproductive effects.

Along with its favorable prognostic role, CLCA2 inhibits growth and metastasis of nasopharyngeal carcinoma cells via inhibition of FAK/ERK signaling

Background

CLCA2 was reported as a tumor suppressor and disregulated in breast cancer. However, its function in tumor growth and metastasis in NPC has rarely been reported. In this study, we investigated the functional and molecular mechanisms by which CLCA2 influences NPC.

Methods

CLCA2 expression in human NPC cell lines and tissues was examined via real-time PCR (RT-PCR), Western blot and IHC. The biological roles of CLCA2 in proliferative, migration and invasion of NPC cell lines was evaluated in 5-8F, S18, S26 and SUNE-1 cells. Cell viability, migration and invasion were assessed in vitro by MTS, colony formation and transwell assay, respectively. CLCA2 in growth and metastasis of NPC were evaluated in vivo through NPC xenograft tumor growth, lung metastatic mice model and popliteal lymph node (LN) metastasis model.

Results

Overexpression of CLCA2 significantly decreased proliferation, migration and invasion of NPC cells. In contrast, knockdown of CLCA2 elicited the opposite effects. CLCA2 overexpression suppressed xenograft tumor growth and lung, popliteal lymph node (LN) metastasis in vivo. CLCA2 inhibited tumor metastasis through suppressing epithelial-Mesenchymal transition (EMT) and in-activating FAK/ERK1/2 signaling pathway in NPC cells. Immunohistochemical staining of 143 NPC samples revealed that CLCA2 expression was an independent, favorable prognostic factor for overall survival and distant metastasis-free survival of patients. In addition, inhibition of FAK and ERK1/2 reversed CLCA2 silencing-induced tumor cell migration. Furthermore, inhibitors against chloride channels suppressed NPC cellular migration which could have been enhanced by the presence of CLCA2.

Conclusion

CLCA2 suppress NPC proliferation, migration, invasion and epithelial-mesenchymal transition through inhibiting FAK/ERK signaling.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0692-8) contains supplementary material, which is available to authorized users.

Differential role of intravenous anesthetics in colorectal cancer progression: implications for clinical application

Anesthetics are unavoidable to colorectal cancer (CRC) patients who underwent surgical treatment. Thus, the molecular mechanisms underlying the role of the intravenous anesthetics in CRC metastasis are still unclear. In this study, the effects of intravenous anesthetics, such as propofol, etomidate and dexmedetomidine, on cell migration were determined. The migration of CRC cells was inhibited by propofol in vitro, but not in vivo. Etomidate, however, promoted the migration of CRC cells both in vitro and in vivo. Epithelial-mesenchymal transition (EMT) mediated the promotive effect of propofol and etomidate on the migration of CRC cells through PI3K/AKT signaling pathway. Dexmedetomidine alone or in combination with propofol or etomidate had minor effect on the migration of CRC cells. These findings indicate that propofol inhibites CRC cell migration in vitro. Etomidate playes a role for prompting CRC metastasis progression by activating (PI3K)/AKT signaling and inducing EMT. It provides an important hint for the clinical application of these anesthetics.

Hippo pathway contributes to cisplatin resistant-induced EMT in nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a kind of head-neck malignant tumor derived from the nasopharyngeal epithelium and is mainly prevalent in Southern China and Southeast Asia countries. Cisplatin (DDP) provides the first-line therapeutic administration in NPC patients. However, chemoresistance has been a main barrier and caused bad treatment outcome in NPC therapy. To understand the molecular mechanism of acquired resistance to DDP, multiple methods were performed to examine the morphocytology and molecular changes in DDP-resistant NPC cells. We found that drug resistance cells displayed epithelial-mesenchymal transition (EMT) characteristics. DDP-resistant NPC cells exhibited enhanced migration and invasion potential. Moreover, overexpression of TAZ, one key gene in Hippo pathway, is closely associated with the DDP resistance of NPC cells and its EMT properties. Depletion of TAZ in DDP-resistant cells reversed EMT phenotypes to MET characteristics and restored chemosensitivity of DDP-resistant cells to DDP treatment. These results suggest that inactivation of TAZ could be a promising approach for the treatment of NPC patients.

Secreted Protein Acidic and Rich in Cysteine (SPARC) Enhances Cell Proliferation, Migration, and Epithelial Mesenchymal Transition, and SPARC Expression is Associated with Tumor Grade in Head and Neck Cancer

Secreted protein acidic and rich in cysteine (SPARC) is a secreted protein which is involved in various biological processes. SPARC expression is associated with tumor metastasis and poor prognosis in several types of cancer. However, the SPARC-induced signaling pathway was not fully understood in head and neck cancer. In this study, our results showed that SPARC treatment promoted cell proliferation and migration in head and neck cancer cell lines FaDu and Detroit 562. In addition, SPARC induced expression of epithelial mesenchymal transition (EMT) regulators, including Slug, Snail, and Twist in Detroit 562. The results of phospho-kinase array analysis showed that SPARC treatment increased phosphorylation of some molecules including protein kinase B (PKB/AKT), ribosomal S6 kinase (RSK), and extracellular signal–regulated kinases (ERK). The expression of SPARC-induced EMT regulator Slug was suppressed by AKT inhibitor, but not ERK and RSK inhibitors. The SPARC expression in grade IV tumor samples is higher when compared to that in grade I–III tumor samples. Our results suggest that SPARC treatment enhances the EMT signaling pathway via activation of AKT, and exogenous SPARC and tumor expressing SPARC might be associated with tumor progression in head and neck cancers.

ZNRF3 Inhibits the Invasion and Tumorigenesis in Nasopharyngeal Carcinoma Cells by Inactivating the Wnt/β-Catenin Pathway

Zinc and ring finger 3 (ZNRF3), which belongs to the E3 ubiquitin ligase family, is involved in the progression and development of cancer. However, the expression and function of ZNRF3 in human nasopharyngeal carcinoma (NPC) remain unclear. Thus, the aim of this study was to investigate the role of ZNRF3 in human NPC. Our results showed that ZNRF3 was downregulated in NPC cell lines. Restoration of ZNRF3 significantly inhibited the proliferation of NPC cells and tumor xenograft growth in vivo. In addition, overexpression of ZNRF3 suppressed migration and invasion, as well as attenuated the epithelial-mesenchymal transition (EMT) process in NPC cells. Furthermore, restoration of ZNRF3 obviously downregulated the expression levels of β-catenin, cyclin D1, and c-Myc in NPC cells. In conclusion, these data suggest that ZNRF3 inhibited the metastasis and tumorigenesis via suppressing the Wnt/β-catenin signaling pathway in NPC cells. Thus, ZNRF3 may act as a novel molecular target for the treatment of NPC.

High FMNL3 expression promotes nasopharyngeal carcinoma cell metastasis: role in TGF-β1-induced epithelia-to-mesenchymal transition

Formin-like 3 (FMNL3) plays a crucial role in cytoskeletal mediation and is potentially a biomarker for cell migration; however, its role in cancer metastasis remains unknown. In this study, we found elevated FMNL3 protein expression in clinical nasopharyngeal carcinoma (NPC) tissues. FMNL3 expression positively correlated to the clinical stage, T (tumour), N (lymph node metastasis) and M (distant metastasis) classification of NPC patients. Moreover, FMNL3 positively correlated to Vimentin expression and negatively correlated to E-cadherin expression in clinical NPC samples. In vitro experiments showed that FMNL3 expression was inversely related to NPC cell differentiation status. Overexpression of FMNL3 led to epithelial-to-mesenchymal transition (EMT) in well differentiated CNE1 cells. TGF-β1-treated poorly differentiated CNE2 cells showed changes in EMT accompanied by enhanced FMNL3 expression and cell migration. On the contrary, knockdown of FMNL3 partially attenuated the TGF-β1-promoted CNE2 cell migration, together with associated changes in EMT markers. Finally, knockdown of FMNL3 also weakened EMT in tumours in xenographs. Our study indicates for the first time that TGF-β1/FMNL3 signalling may be a novel mechanism mediating EMT in NPC, which is closely associated with NPC metastasis.

Genetic variations in the PI3K-PTEN-AKT-mTOR pathway are associated with distant metastasis in nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

Distant metastasis is the primary failure pattern of nasopharyngeal carcinoma(NPC) in intensity-modulated radiation therapy(IMRT) era. This study was conducted to find the impact of genetic variations in the phosphatidylinositol 3-kinase(PI3K)/phosphatase and tensin homologue(PTEN)/v-akt murine thymoma viral oncogene homologue(AKT)/mammalian target of rapamycin(mTOR) pathway on the risk of distant metastasis in NPC. We genotyped 16 single-nucleotide polymorphisms(SNPs) in five core genes in this pathway from 496 patients treated by IMRT with or without chemotherapy. The relationships between genetic polymorphisms and distant progression were evaluated. We observed that two loci in the AKT1 gene(rs3803300 and rs2494738 alone or combined) were associated with prognosis, with patients carrying at least one variant allele had significantly reduced risk of distant failure, especially in N2-3 group. In addition, we found that genetic variation may had some joint effect with N classification in recursive-partitioning analysis(RPA) analysis, with which patients were stratified into four different risk subgroups (RPA model): RPA1(low risk), RPA2(moderate risk), RPA3(high risk) and RPA4(highest risk). Our findings suggested that genetic variations within the PI3K signaling pathway modulate the development and invasion of NPC patients. Further research is needed to replicate the study in other centers and races, and to unravel the functional significance of these polymorphisms.

The roles of microRNAs related with progression and metastasis in human cancers

Metastasis is an important factor in predicting the prognosis of the patients with cancers and contributes to high cancer-related mortality. Recent studies indicated that microRNAs (miRNAs) played a functional role in the initiation and progression of human malignancies. MicroRNAs are small non-coding RNAs of about 22 nucleotides in length that can induce messenger RNA (mRNA) degradation or repress mRNA translation by binding to the 3' untranslated region (3'-UTR) of their target genes. Overwhelming reports indicated that miRNAs could regulate cancer invasion and metastasis via epithelial-to-mesenchymal transition (EMT)-related and/or non-EMT-related mechanisms. In this review, we concentrate on the underlying mechanisms of miRNAs in regulating cancer progression and metastasis.

PTPRG suppresses tumor growth and invasion via inhibition of Akt signaling in nasopharyngeal carcinoma

Protein Tyrosine Phosphatase, Receptor Type G (PTPRG) was identified as a candidate tumor suppressor gene in nasopharyngeal carcinoma (NPC). PTPRG induces significant in vivo tumor suppression in NPC. We identified EGFR as a PTPRG potential interacting partner and examined this interaction. Dephosphorylation of EGFR at EGFR-Y1068 and -Y1086 sites inactivated the PI3K/Akt signaling cascade and subsequent down-regulation of downstream pro-angiogenic and -invasive proteins (VEGF, IL6, and IL8) and suppressed tumor cell proliferation, angiogenesis, and invasion. The effect of Akt inhibition in NPC cells was further validated by Akt knockdown experiments in the PTPRG-down-regulated NPC cell lines. Our results suggested that inhibition of Akt in NPC cells induces tumor suppression at both the in vitro and in vivo levels, and also importantly, in vivo metastasis. In conclusion, we confirmed the vital role of PTPRG in inhibiting Akt signaling with the resultant suppression of in vivo tumorigenesis and metastasis.

Upregulation of metastasis-associated gene 2 promotes cell proliferation and invasion in nasopharyngeal carcinoma

Aims

Metastasis-associated gene 2 (MTA2) is reported to play an important role in tumor progression, but little is known about the role of MTA2 in nasopharyngeal carcinoma (NPC). The aim of the study was to explore the expression and function of MTA2 in NPC.

Methods

Expression of MTA2 in NPC tissues and cell lines was detected by immunohistochemistry and Western blotting. Relationship between MTA2 expression and clinicopathological features was analyzed. Stable MTA2-overexpressing and MTA2-siliencing NPC cells were established by transfection with plasmids encoding MTA2 cDNA and lentivirus-mediated short hairpin RNA, respectively. Cell viability was determined by Cell Counting Kit-8 and colony formation assay. Cell migration ability was evaluated by wound healing and transwell invasion assay. The impact of MTA2 knockdown on growth and metastasis of CNE2 cells in vivo was determined by nude mouse xenograft models. Expression of several Akt pathway proteins was detected by Western blotting.

Results

MTA2 was upregulated in NPC tissues and three NPC cell lines detected (CNE1, CNE2, and HNE1). MTA2 expression was related to clinical stage and lymph node metastasis of patients with NPC. MTA2 upregulation promoted proliferation and invasion of CNE1 cells, while MTA2 depletion had opposite effects on CNE2 cells. Moreover, MTA2 depletion suppressed growth and metastasis of CNE2 cells in vivo. MTA2 overexpression activated Akt and upregulated the expression of matrix metalloproteinase 7 and cyclin D1.

Conclusion

We conclude that MTA2 acts as an oncogene in tumorigenesis of NPC. MTA2 may be a potential target for gene therapy in NPC.

MiR-205 promotes proliferation, migration and invasion of nasopharyngeal carcinoma cells by activation of AKT signalling

Objective

To examine the role of microRNA (miR)-205 in proliferation, migration and invasion of nasopharyngeal carcinoma (NPC).

Methods

The human NPC cell line CNE2 was transfected with miR-205 mimic, anti-miR-205 inhibitor or scrambled oligonucleotide (control). Cell proliferation was assessed via MTT assay. Cell migration and invasion were evaluated by transwell migration and Matrigel® invasion assay, respectively. Radiation induced apoptosis was quantified via Caspase-Glo3/7 assay. Apoptotic proteins and epithelial–mesenchymal transition (EMT) proteins were semiquantified by Western blot analysis.

Results

Overexpression of miR-205 increased the proliferation, migration and invasion of CNE2 cells, and decreased radiation-induced apoptosis compared with control cells. MiR-205 overexpression downregulated E-cadherin and upregulated Snail expression via downregulation of PTEN and upregulation of AKT.

Conclusion

MiR-205 plays vital roles in tumourigenesis and tumour progression in NPC, and may be a potential treatment target.

Pathophysiological Functions of Rnd3/RhoE

Rnd3, also known as RhoE, belongs to the Rnd subclass of the Rho family of small guanosine triphosphate (GTP)-binding proteins. Rnd proteins are unique due to their inability to switch from a GTP-bound to GDP-bound conformation. Even though studies of the biological function of Rnd3 are far from being concluded, information is available regarding its expression pattern, cellular localization, and its activity, which can be altered depending on the conditions. The compiled data from these studies implies that Rnd3 may not be a traditional small GTPase. The basic role of Rnd3 is to report as an endogenous antagonist of RhoA signaling-mediated actin cytoskeleton dynamics, which specifically contributes to cell migration and neuron polarity. In addition, Rnd3 also plays a critical role in arresting cell cycle distribution, inhibiting cell growth, and inducing apoptosis and differentiation. Increasing data have shown that aberrant Rnd3 expression may be the leading cause of some systemic diseases; particularly highlighted in apoptotic cardiomyopathy, developmental arrhythmogenesis and heart failure, hydrocephalus, as well as tumor metastasis and chemotherapy resistance. Therefore, a better understanding of the function of Rnd3 under different physiological and pathological conditions, through the use of suitable models, would provide a novel insight into the origin and treatment of multiple human diseases.

Role of the LKB1/AMPK pathway in tumor invasion and metastasis of cancer cells (Review)

Liver kinase B1 (LKB1), also known as serine/threo-nine kinase 11 (STK11), is a tumor suppressor that is inactivated in Peutz-Jeghers familial cancer syndrome. LKB1 phosphorylates and activates AMP-activated protein kinase (AMPK), which negatively regulates cancer cell proliferation and metabolism. However, recent evidence demonstrates that the LKB1/AMPK pathway is involved in the process of tumor invasion and migration, which is an important hallmark of carcinoma progression to higher pathological grades of malignancy. This review focuses on the function of the LKB1/AMPK pathway in the invasion and migration of cancer cells and provides an overview of therapeutic strategies aimed at this pathway in malignant tumors.

Downregulation of miR203 induces overexpression of PIK3CA and predicts poor prognosis of gastric cancer patients

Background

Despite advances in clinical therapies and technologies, the prognosis for patients with gastric cancer is still poor. The aim of this study is to investigate new predictive markers for prognosis of gastric cancer.

Methods

In this study, we evaluated the expression pattern of PIK3CA in 107 gastric cancer specimens and their adjacent nontumorous tissues. PIK3CA siRNA was synthesized and transfected into gastric cancer cell lines. Colony formation and MTT assays were employed to analyze the cell proliferation. PIK3CA expression was examined by using immunohistochemical analysis and Western blot assay. Transwell invasion assay was used to detect the invasion capability of the cells. Luciferase activity was examined by using 3′-untranslated region luciferase reporter assays.

Results

We observed that PIK3CA was significantly upregulated in gastric cancer tissues. High expression level of PIK3CA was detectable in 48 (44.86%) of the gastric cancer specimens, and correlated with poor prognosis. In addition, our study indicated that miR203 inhibits cell proliferation and invasion via directly targeting and suppressing the PIK3CA expression. MiR203 expression is downregulated in gastric cancer tissues. Moreover, low expression level of miR203 predicted poor prognosis of gastric patients and induced overexpression of PIK3CA. Our further study also reported that overexpression of miR203 inhibited phosphorylation of AKT, while cotransfection of PIK3CA reversed the effect of miR203.

Conclusion

Our study suggested a miR203-PIK3CA-AKT signaling pathway in gastric cancer cells. This signaling pathway might play an important role in gastric cancer genesis and development.