Plasminogen activator inhibitor 1 RNAi suppresses gastric cancer metastasis in vivo

Expression of Serpin Family E Member 1 (SERPINE1) Is Associated with Poor Prognosis of Gastric Adenocarcinoma

BACKGROUND

The aberrant expression of serpin family E member 1 (SERPINE1) is associated with carcinogenesis. This study assessed the alteration of SERPINE1 expression for an association with gastric adenocarcinoma prognosis.

METHODS

The Cancer Genome Atlas (TCGA) dataset was applied to investigate the impact of SERPINE1 expression on the survival of patients afflicted with gastric cancer. Subsequently, 136 samples from the Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University were subjected to qRT-PCR and Western blot to validate the expression level of SERPINE1 between tumor and adjacent normal tissues. The correlation between the expression of SERPINE1 with the clinicopathological features in TCGA patients was analyzed using Wilcoxon signed-rank and logistic regression tests. The potential molecular mechanism associated with SERPINE1 expression in gastric cancer were confirmed using gene set enrichment analysis (GSEA).

RESULTS

The TCGA data showed that SERPINE1 was overexpressed in tumor tissues compared to normal mucosae and associated with the tumor T stage and pathological grade. SERPINE1 overexpression was associated with the poor overall survival (OS) of patients. The findings were confirmed with 136 patients, that is, SERPINE1 expression was associated with poor OS (hazard ratio (HR): 1.82; 95% confidence interval (CI): 0.84-1.83; p = 0.012)) as an independent predictor (HR: 2.11, 95% CI: 0.81-2.34; p = 0.009). The resulting data were further processed by GSEA showed that SERPINE1 overexpression was associated with the activation of EPITHELIAL_MESENCHYMAL_TRANSITION, TNFA_SIGNALING_VIA_NFKB, INFLAMMATORY_RESPONSE, ANGIOGENESIS, and HYPOXIA.

CONCLUSIONS

SERPINE1 overexpression is associated with a poor gastric cancer prognosis.

The Regulatory Network of Gastric Cancer Pathogenesis and Its Potential Therapeutic Active Ingredients of Traditional Chinese Medicine Based on Bioinformatics, Molecular Docking, and Molecular Dynamics Simulation

Objective. This study aims to investigate the functional gene network in gastric carcinogenesis by using bioinformatics; besides, the diagnostic utility of key genes and potential active ingredients of traditional Chinese medicine (TCM) for treatment in gastric cancer have been explored. Methods. The Cancer Genome Atlas and Gene Expression Omnibus databases have been applied to analyze the differentially expressed genes (DEGs) between gastric cancer and normal gastric tissues. Then, the DEGs underwent Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses using the Metascape database. The STRING database and the Cytoscape software were utilized for the protein-protein interaction network of DEGs and hub genes screening. Furthermore, survival and expression analyses of hub genes were conducted using Gene Expression Profiling Interactive Analysis and Human Protein Atlas databases. By using the Comparative Toxicogenomics Database, the hub genes interconnected with active ingredients of TCM were analyzed to provide potential information for the treatment of gastric cancer. After the molecular docking of the active ingredients of TCM to specific hub gene receptor proteins, the molecular dynamics simulation GROMACS was applied to validate the conformation of the strongest binding ability in the molecular docking. Results. A total of 291 significant DEGs were found, from which 12 hub genes were screened out. Among these hub genes, the expressions of five hub genes including COL1A1, COL5A2, MMP12, SERPINE1, and VCAN were significantly correlated with the overall survival. Furthermore, four potential therapeutic active ingredients of TCM were acquired, including quercetin, resveratrol, emodin, and schizandrin B. In addition, the molecular docking results exhibited that the active ingredients of TCM formed stable binding with the hub gene targets. SERPINE1 (3UT3)-Emodin and COL1A1 (7DV6)-Quercetin were subjected to molecular dynamics simulations as conformations of continuing research significance, and both were found to be stably bound as a result of the interaction of van der Waals potentials, electrostatic, and hydrogen bonding. Conclusion. Our findings may provide novel insights and references for the screening of biomarkers, the prognostic evaluation, and the identification of potential active ingredients of TCM for gastric cancer treatment.

Naa10p promotes cell invasiveness of esophageal cancer by coordinating the c-Myc and PAI1 regulatory axis

N-α-acetyltransferase 10 protein, Naa10p, is involved in various cellular functions impacting tumor progression. Due to its capacity to acetylate a large spectrum of proteins, both oncogenic and tumor-suppressive roles of Naa10p have been documented. Here, we report an oncogenic role of Naa10p in promoting metastasis of esophageal cancer. NAA10 is more highly expressed in esophageal cancer tissues compared to normal tissues. Higher NAA10 expression also correlates with poorer survival of esophageal cancer patients. We found that NAA10 expression was transcriptionally regulated by the critical oncogene c-Myc in esophageal cancer. Furthermore, activation of the c-Myc-Naa10p axis resulted in upregulated cell invasiveness of esophageal cancer. This increased cell invasiveness was also elucidated to depend on the enzymatic activity of Naa10p. Moreover, Naa10p cooperated with Naa15p to interact with the protease inhibitor, PAI1, and prevent its secretion. This inhibition of PAI1 secretion may derive from the N-terminal acetylation effect of the Naa10p/Naa15p complex. Our results establish the significance of Naa10p in driving metastasis in esophageal cancer by coordinating the c-Myc-PAI1 axis, with implications for its potential use as a prognostic biomarker and therapeutic target for esophageal cancer.

Oncolytic virus: A catalyst for the treatment of gastric cancer

Gastric cancer (GC) is a leading contributor to global cancer incidence and mortality. According to the GLOBOCAN 2020 estimates of incidence and mortality for 36 cancers in 185 countries produced by the International Agency for Research on Cancer (IARC), GC ranks fifth and fourth, respectively, and seriously threatens the survival and health of people all over the world. Therefore, how to effectively treat GC has become an urgent problem for medical personnel and scientific workers at this stage. Due to the unobvious early symptoms and the influence of some adverse factors such as tumor heterogeneity and low immunogenicity, patients with advanced gastric cancer (AGC) cannot benefit significantly from treatments such as radical surgical resection, radiotherapy, chemotherapy, and targeted therapy. As an emerging cancer immunotherapy, oncolytic virotherapies (OVTs) can not only selectively lyse cancer cells, but also induce a systemic antitumor immune response. This unique ability to turn unresponsive 'cold' tumors into responsive 'hot' tumors gives them great potential in GC therapy. This review integrates most experimental studies and clinical trials of various oncolytic viruses (OVs) in the diagnosis and treatment of GC. It also exhaustively introduces the concrete mechanism of invading GC cells and the viral genome composition of adenovirus and herpes simplex virus type 1 (HSV-1). At the end of the article, some prospects are put forward to determine the developmental directions of OVTs for GC in the future.

SERBP1 affects the apoptotic level by regulating the expression and alternative splicing of cellular and metabolic process genes in HeLa cells

Background

RNA-binding proteins (RBPs) have important roles in orchestrating posttranscriptional regulation and modulating many tumorigenesis events. SERBP1 has been recognized as an important regulator in multiple cancers, while it remains unclear whether SERBP1-regulated gene expression at the transcriptome-wide level is significantly correlated with tumorigenesis.

Methods

We overexpressed SERBP1 in HeLa cells and explored whether SERBP1 overexpression (SERBP1-OE) affects the proliferation and apoptosis of HeLa cells. We analyzed the transcriptome-wide gene expression changes and alternative splicing changes mediated by SERBP1-OE using the transcriptome sequencing method (RNA-seq). RT-qPCR was conducted to assay SERBP1-regulated alternative splicing.

Results

SERBP1-OE induced the apoptosis of HeLa cells. The downregulated genes were strongly enriched in the cell proliferation and apoptosis pathways according to the GO analysis, including FOS, FOSB, PAK6 and RAB26. The genes undergoing at least one SERBP1-regulated alternative splicing event were enriched in transcriptional regulation, suggesting a mechanism of the regulation of gene expression, and in pyruvate and fatty acid metabolic processes critical for tumorigenesis events. The SERBP1-regulated alternative splicing of ME3, LPIN3, CROT, PDP1, SLC27A1 and ALKBH7 was validated by RT-qPCR analysis.

Conclusions

We for the first time demonstrated the cellular function and molecular targets of SERBP1 in HeLa cells at transcriptional and post-transcriptional levels. The SERBP1-regulated gene expression and alternative splicing networks revealed by this study provide important information for exploring the functional roles and regulatory mechanisms of SERBP1 in cancer development and progression.

Construction and validation of a novel coagulation-related 7-gene prognostic signature for gastric cancer

Background: Gastric cancer (GC) is the most common malignant tumor. Due to the lack of practical molecular markers, the prognosis of patients with advanced gastric cancer is still poor. A number of studies have confirmed that the coagulation system is closely related to tumor progression. Therefore, the purpose of this study was to construct a coagulation-related gene signature and prognostic model for GC by bioinformatics methods.

Methods: We downloaded the gene expression and clinical data of GC patients from the TCGA and GEO databases. In total, 216 coagulation-related genes (CRGs) were obtained from AmiGO 2. Weighted gene co-expression network analysis (WGCNA) was used to identify coagulation-related genes associated with the clinical features of GC. Last absolute shrinkage and selection operator (LASSO) Cox regression was utilized to shrink the relevant predictors of the coagulation system, and a Coag-Score prognostic model was constructed based on the coefficients. According to this risk model, GC patients were divided into high-risk and low-risk groups, and overall survival (OS) curves and receiver operating characteristic (ROC) curves were drawn in the training and validation sets, respectively. We also constructed nomograms for predicting 1-, 2-, and 3-year survival in GC patients. Single-sample gene set enrichment analysis (ssGSEA) was exploited to explore immune cells’ underlying mechanisms and correlations. The expression levels of coagulation-related genes were verified by real-time quantitative polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC).

Results: We identified seven CRGs employed to construct a Coag-Score risk model using WGCNA combined with LASSO regression. In both training and validation sets, GC patients in the high-risk group had worse OS than those in the low-risk group, and Coag-Score was identified as an independent predictor of OS, and the nomogram provided a quantitative method to predict the 1-, 2-, and 3-year survival rates of GC patients. Functional analysis showed that Coag-Score was mainly related to the MAPK signaling pathway, complement and coagulation cascades, angiogenesis, epithelial–mesenchymal transition (EMT), and KRAS signaling pathway. In addition, the high-risk group had a significantly higher infiltration enrichment score and was positively associated with immune checkpoint gene expression. Conclusion: Coagulation-related gene models provide new insights and targets for the diagnosis, prognosis prediction, and treatment management of GC patients.

Ligand-mediated PAI-1 inhibition in a mouse model of peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) present a ubiquitous clinical conundrum in all intra-abdominal malignancies. Via functional and transcriptomic experiments of ascites-treated PC cells, we identify STAT3 as a key signaling pathway. Integrative analysis of publicly available databases and correlation with clinical cohorts (n = 7,359) reveal putative clinically significant activating ligands of STAT3 signaling. We further validate a 3-biomarker prognostic panel in ascites independent of clinical covariates in a prospective study (n = 149). Via single-cell sequencing experiments, we uncover that PAI-1, a key component of the prognostic biomarker panel, is largely secreted by fibroblasts and mesothelial cells. Molecular stratification of ascites using PAI-1 levels and STAT3 activation in ascites-treated cells highlight a therapeutic opportunity based on a phenomenon of paracrine addiction. These results are recapitulated in patient-derived ascites-dependent xenografts. Here, we demonstrate therapeutic proof of concept of direct ligand inhibition of a prognostic target within an enclosed biological space.

Experimental and Clinical Evidence Supports the Use of Urokinase Plasminogen Activation System Components as Clinically Relevant Biomarkers in Gastroesophageal Adenocarcinoma

Simple Summary

Patients with gastric and oesophageal adenocarcinomas (GOCs) have short life expectancies as their tumours spread to other sites early. This is facilitated by the increased expression of the urokinase plasminogen activation system (uPAS); a feature of the majority of GOCs. There is increasing appreciation of the importance of uPAS expression in a range of cell types within the tumour microenvironment. Abundant clinical evidence indicates that altered expression of uPAS proteins is associated with worse outcomes, including time to tumour recurrence and patient survival. Emerging technologies, including liquid biopsy, suggest a role of uPAS for the detection of circulating tumour cells, which are responsible for the dissemination of cancers. We review and summarise pre-clinical and clinical data that supports the use of uPAS as a biomarker in GOC.

Abstract

Gastric and oesophageal cancers (GOCs) are lethal cancers which metastasise early and recur frequently, even after definitive surgery. The urokinase plasminogen activator system (uPAS) is strongly implicated in the invasion and metastasis of many aggressive tumours including GOCs. Urokinase plasminogen activator (uPA) interaction with its receptor, urokinase plasminogen activator receptor (uPAR), leads to proteolytic activation of plasminogen to plasmin, a broad-spectrum protease which enables tumour cell invasion and dissemination to distant sites. uPA, uPAR and the plasminogen activator inhibitor type 1 (PAI-1) are overexpressed in some GOCs. Accumulating evidence points to a causal role of activated receptor tyrosine kinase pathways enhancing uPAS expression in GOCs. Expression of these components are associated with poorer clinicopathological features and patient survival. Stromal cells, including tumour-associated macrophages and myofibroblasts, also express the key uPAS proteins, supporting the argument of stromal involvement in GOC progression and adverse effect on patient survival. uPAS proteins can be detected on circulating leucocytes, circulating tumour cells and within the serum; all have the potential to be developed into circulating biomarkers of GOC. Herein, we review the experimental and clinical evidence supporting uPAS expression as clinical biomarker in GOC, with the goal of developing targeted therapeutics against the uPAS.

Identification of a nine-gene prognostic signature for gastric carcinoma using integrated bioinformatics analyses

BACKGROUND

Gastric carcinoma (GC) is one of the most aggressive primary digestive cancers. It has unsatisfactory therapeutic outcomes and is difficult to diagnose early.

AIM

To identify prognostic biomarkers for GC patients using comprehensive bioinformatics analyses.

METHODS

Differentially expressed genes (DEGs) were screened using gene expression data from The Cancer Genome Atlas and Gene Expression Omnibus databases for GC. Overlapping DEGs were analyzed using univariate and multivariate Cox regression analyses. A risk score model was then constructed and its prognostic value was validated utilizing an independent Gene Expression Omnibus dataset (GSE15459). Multiple databases were used to analyze each gene in the risk score model. High-risk score-associated pathways and therapeutic small molecule drugs were analyzed and predicted, respectively.

RESULTS

A total of 95 overlapping DEGs were found and a nine-gene signature (COL8A1, CTHRC1, COL5A2, AADAC, MAMDC2, SERPINE1, MAOA, COL1A2, and FNDC1) was constructed for the GC prognosis prediction. Receiver operating characteristic curve performance in the training dataset (The Cancer Genome Atlas-stomach adenocarcinoma) and validation dataset (GSE15459) demonstrated a robust prognostic value of the risk score model. Multiple database analyses for each gene provided evidence to further understand the nine-gene signature. Gene set enrichment analysis showed that the high-risk group was enriched in multiple cancer-related pathways. Moreover, several new small molecule drugs for potential treatment of GC were identified.

CONCLUSION

The nine-gene signature-derived risk score allows to predict GC prognosis and might prove useful for guiding therapeutic strategies for GC patients.

The plasminogen activator inhibitor-1 paradox in cancer: a mechanistic understanding

The paradoxical pro-tumorigenic function of plasminogen activator inhibitor 1 (PAI-1, aka Serpin E1) in cancer progression and metastasis has been the subject of an abundant scientific literature that has pointed to a pro-angiogenic role, a growth and migration stimulatory function, and an anti-apoptotic activity, all directed toward promoting tumor growth, cancer cell survival, and metastasis. With uPA, PAI-1 is among the most reliable biomarkers and prognosticators in many cancer types. More recently, a novel pro-tumorigenic function of PAI-1 in cancer-related inflammation has been demonstrated. These multifaceted activities of PAI-1 in cancer progression are explained by the complex structure of PAI-1 and its multiple functions that go beyond its anti-fibrinolytic and anti-plasminogen activation activities. However, despite the multiple evidences supporting a pro-tumorigenic role of PAI-1 in cancer, and the development of several inhibitors, targeting PAI-1, has remained elusive. In this article, the various mechanisms responsible for the pro-tumorigenic functions of PAI-1 are reviewed with emphasis on its more recently described contribution to cancer inflammation. The challenges of targeting PAI-1 in cancer therapy are then discussed.

Proteomic analysis of evodiamine-induced cytotoxicity in thyroid cancer cells

Evodiamine is a natural product extracted from herbal plants such as Tetradium which has shown to have anti-fat uptake and anti-proliferation properties. However, the effects of evodiamine on the behavior of thyroid cancers are largely unknown. To determine if evodiamine might be useful in the treatment of thyroid cancer and its cytotoxic mechanism, we analyzed the impact of evodiamine treatment on differential protein expression in human thyroid cancer cell line ARO using lysine-labeling two-dimensional difference gel electrophoresis (2D-DIGE) combined with mass spectrometry (MS). This study demonstrated 77 protein features that were significantly changed in protein expression and revealed evodiamine-induced cytotoxicity in thyroid cancer cells involves dysregulation of protein folding, cytoskeleton, cytoskeleton regulation and transcription control. Our work shows that this combined proteomic strategy provides a rapid method to study the molecular mechanisms of evodiamine-induced cytotoxicity in thyroid cancer cells. The identified targets may be useful for further evaluation as potential targets in thyroid cancer therapy.

Plasminogen activator inhibitor-1 in cancer research. Biomed Pharmacother. 2018;105:83-94. [PMID: 29852393 DOI: 10.1016/j.biopha.2018.05.119]

[Despite as a major inhibitor of urokinase (uPA), paradoxically,] Plasminogen activator inhibitor-1 (PAI-1) has been validated to be highly expressed in various types of tumor biopsy tissues or plasma compared with controls based on huge clinical data bases analysis, more importantly, PAI-1 alone or in conjunction with uPA have been identified as prognostic for disease progression and relapse in certain cancer types. particularly in breast cancer. In addition to play important roles in cell adhesion, migration and invasion, PAI-1 has been reported to induce tumor vascularization and thus promote cell dissemination and tumor metastasis. Furthermore, there are many tumor promoting factors involved in the modulation of PAI-1 expression and activity, which will strengthen the pro-tumorigenic roles of PAI-1. Undoubtedly, PAI-1 may be a promising target for therapeutic intervention of specific cancer treatment. In fact, some PAI-1 inhibitors are currently being evaluated in cancer therapy, which may be developed to new antitumor agents in the future.

Construction of a Bcl-2-shRNA expression vector and its effect on the mitochondrial apoptosis pathway in SW982 cells

Apoptosis is considered to serve an important role in the pathogenesis of rheumatoid arthritis. The aim of the present study was to construct Bcl-2-short hairpin (sh)RNA expression vectors and transfect them into human synovial sarcoma SW982 cells, in order to screen for an effective interference sequence and analyze the effects of this interference on the expression levels of Bcl-2 and other molecules associated with the mitochondrial apoptosis pathway. Three different shRNAs (Bcl-2-sh1, 2 and 3) were designed according to the human Bcl-2 mRNA target sequence and were transformed into competent DH5α Escherichia coli cells following the construction of an expression vector, which was then transfected into SW982 cells. SW982 cells were grouped into a control group (transfected with a negative control shRNA), and Bcl-2-sh1, Bcl-2-sh2 and Bcl-2-sh3 groups (transfected with Bcl-2-sh1, 2 and 3, respectively). The expression levels of Bcl-2 mRNA were detected using reverse transcription-quantitative PCR (RT-qPCR). Bcl-2-sh1 was identified as the most effective shRNA sequence for interference, and was used for subsequent experiments. The mRNA and protein expression levels of Bcl-2, Bax, CytC and Caspase-3 were detected in SW982 cells by RT-qPCR and western blotting at various time-points (48 and 72 h) following transfection with Bcl-2-sh1, in order to observe the effectiveness of this interference. Compared with the control group, the expression levels of Bcl-2 were decreased, while those of Bax, CytC and Caspase-3 were increased in Bcl-2-sh1-transfected cells (P<0.01). The interference effect was greater at 48 h than at 72 h. In summary, an effective shRNA sequence (Bcl-2-sh1) targeting the Bcl-2 gene was identified from three candidates, and was demonstrated to significantly interfere with the expression of Bcl-2, Bax, CytC and Caspase-3 when transfected into SW982 cells. The interference effect of Bcl-2-sh1 was more pronounced at 48 h than at 72 h post-transfection.

Intracellular Expression of PAI-1 Specific Aptamers Alters Breast Cancer Cell Migration, Invasion and Angiogenesis

Plasminogen activator inhibitor-1 (PAI-1) is elevated in various cancers, where it has been shown to effect cell migration and invasion and angiogenesis. While, PAI-1 is a secreted protein, its intercellular levels are increased in cancer cells. Consequently, intracellular PAI-1 could contribute to cancer progression. While various small molecule inhibitors of PAI-1 are currently being investigated, none specifically target intracellular PAI-1. A class of inhibitors, termed aptamers, has been used effectively in several clinical applications. We previously generated RNA aptamers that target PAI-1 and demonstrated their ability to inhibit extracellular PAI-1. In the current study we explored the effect of these aptamers on intracellular PAI-1. We transiently transfected the PAI-1 specific aptamers into both MDA-MB-231 human breast cancer cells, and human umbilical vein endothelial cells (HUVECs) and studied their effects on cell migration, invasion and angiogenesis. Aptamer expressing MDA-MB-231 cells exhibited a decrease in cell migration and invasion. Additionally, intracellular PAI-1 and urokinase plasminogen activator (uPA) protein levels decreased, while the PAI-1/uPA complex increased. Moreover, a significant decrease in endothelial tube formation in HUVECs transfected with the aptamers was observed. In contrast, conditioned media from aptamer transfected MDA-MB-231 cells displayed a slight pro-angiogenic effect. Collectively, our study shows that expressing functional aptamers inside breast and endothelial cells is feasible and may exhibit therapeutic potential.

TEL2 suppresses metastasis by down-regulating SERPINE1 in nasopharyngeal carcinoma

Metastasis is the major cause of treatment failure in patients with nasopharyngeal carcinoma (NPC). However, the molecular mechanisms of NPC metastasis are poorly understood. Here, using our customized gene microarray containing all of the known human transcription factors and the current markers for epithelial-mesenchymal transition, we report that TEL2 was down-regulated in highly metastatic NPC cells and the metastatic tissues in lymph node. Mechanistically, TEL2 inhibits the cell migration and invasion in vitro and metastasis in vivo by releasing its direct suppression on the SERPINE1 promoter in NPC. Consistently, an inverse correlation was observed between the protein levels of TEL2 and SERPINE1 using clinical NPC samples. Collectively, we have provided the first evidence that TEL2 plays a key role in NPC metastasis by directly down-regulating SERPINE1, and that this novel axis of TEL2 / SERPINE1 may be valuable to develop new strategies for treating NPC patients with metastasis.

Overexpression of Plasminogen Activator Inhibitor-1 in Advanced Gastric Cancer with Aggressive Lymph Node Metastasis

Purpose

The purpose of this study is to investigate differentially expressed genes using DNA microarray between advanced gastric cancer (AGC) with aggressive lymph node (LN) metastasis and that with a more advanced tumor stage but without LN metastasis.

Materials and Methods

Five sample pairs of gastric cancer tissue and normal gastric mucosa were taken from three patients with T3N3 stage (highN) and two with T4N0 stage (lowN). Data from triplicate DNA microarray experiments were analyzed, and candidate genes were identified using a volcano plot that showed ≥ 2-fold differential expression and were significant by Welch's t test (p < 0.05) between highN and lowN. Those selected genes were validated independently by reverse-transcriptase–polymerase chain reaction (RT-PCR) using five AGC patients, and tissue-microarray (TMA) comprising 47 AGC patients.

Results

CFTR, LAMC2, SERPINE2, F2R, MMP7, FN1, TIMP1, plasminogen activator inhibitor-1 (PAI-1), ITGB8, SDS, and TMPRSS4 were commonly up-regulated over 2-fold in highN. REG3A, CD24, ITLN1, and WBP5 were commonly down-regulated over 2-fold in lowN. Among these genes, overexpression of PAI-1 was validated by RT-PCR, and TMA showed 16.7% (7/42) PAI-1 expression in T3N3, but none (0/5) in T4N0 (p=0.393).

Conclusion

DNA microarray analysis and validation by RT-PCR and TMA showed that overexpression of PAI-1 is related to aggressive LN metastasis in AGC.

Impact of S-1 plus Cisplatin Neoadjuvant Chemotherapy on Scirrhous Gastric Cancer

OBJECTIVE

This retrospective study aimed to address the therapeutic outcome for scirrhous gastric cancer patients by evaluating the effect of neoadjuvant chemotherapy prior to gastrectomy.

METHODS

Two cycles of a 3-week regimen of fluoropyrimidine S-1 (40 mg/m(2), orally, twice daily), together with cisplatin (60 mg/m(2), intravenously, day 8), were administered to patients, separated by a 2-week rest period. Surgery was performed 3 weeks later in the neoadjuvant group (n = 27). We retrospectively evaluated overall survival and prognostic factors in these patients.

RESULTS

Univariate analysis showed that positive lavage cytology indicated significantly worse prognoses. In the 15 patients who also underwent curative gastrectomies after S-1 plus cisplatin chemotherapy, the pathological response grade was a significant prognostic factor for 5-year survival. Additionally, lymph node metastasis tended to be an adverse prognostic factor.

CONCLUSION

After S-1 plus cisplatin neoadjuvant chemotherapy, a grade 2-3 pathological response may predict favorable outcomes in scirrhous gastric cancer patients receiving curative gastrectomy, but further studies are needed to confirm these results.

Lentivirus-mediated knockdown of CUGBP1 suppresses gastric cancer cell proliferation in vitro

Gastric cancer is the second most common cause of cancer-related death worldwide. This study was designed to examine the role of CUGBP1 in cell growth via an RNA interference (RNAi) lentivirus system in gastric cancer cells in vitro. The expression of CUGBP1 was much stronger in gastric cancer tissues than that in adjacent normal tissues. The lentivirus-mediated knockdown of CUGBP1 resulted in a significant reduction of CUGBP1 expression in MGC-803 gastric cancer cells. The cell viability was remarkably decreased by 50 % after 5 days of infection, as determined by MTT assay. Moreover, the size and the number of colonies formed in MGC-803 cells were markedly reduced in the absence of CUGBP1. Furthermore, the silencing of CUGBP1 downregulated the expression levels of cyclin B1 and cyclin D1, which are involved in cell cycle control. These results clearly indicated that CUGBP1 is essential for the growth of gastric cancer cells. Therefore, silencing of CUGBP1 by RNAi could be developed as a promising therapeutic approach for gastric cancer.

Enhancement of DEN-induced liver tumourigenesis in hepatocyte-specific Lass2-knockout mice coincident with upregulation of the TGF-β1-Smad4-PAI-1 axis

Longevity assurance homolog 2 of yeast LAG1 (Lass2) gene is capable of suppressing the proliferation and metastasis of several types of tumours including liver cancer. In the present study, hepatocyte-specific Lass2-knockout (Lass2 KO) and wild-type (WT) mice were exposed to the carcinogen, diethylnitrosamine (DEN), to induced liver tumours. At week 23 following DEN injection, tumours were produced in 100% of the Lass2 KO mice and 21.4% of the WT mice. At week 40, 100% of the Lass2 KO mice and 78.6% of the WT mice developed tumours, with no distinct significant difference in tumour occurrences between the two genotypes; yet, tumours in the Lass2 KO mouse livers were more numerous and larger in size. Hepatocellular carcinoma (HCC) was confirmed by α-fetoprotein (AFP). PCNA and EdU assays indicated more active proliferation whereas TUNEL assay revealed decreased apoptosis in Lass2 KO livers, when compared with the WT control. The expression of plasminogen activator inhibitor type-1 (PAI-1), a tumour-promoting gene, in the liver tissues of the 2 genotypes was detected using qPCR and western blotting, showing that PAI-1 levels were significantly elevated in Lass2 KO livers at week 40 following DEN introduction. Moreover, the expression of PAI-1-related TGF-β1, Smad-4 and -7 was detected, displaying an elevation in TGF-β1 and Smad-4 (not including Smad-7) in the Lass2 KO livers. Our data demonstrates that i) Lass2 is a protective gene against DEN-induced liver tumourigenesis; and ii) upregulation of the TGF-β1-Smad4-PAI-1 axis may contribute to the vulnerability of Lass2-knockout mice to DEN.

Cell density-dependent nuclear accumulation of ELK3 is involved in suppression of PAI-1 expression

Cell-cell contact regulates the proliferation and differentiation of non-transformed cells, e.g., NIH/3T3 cells show growth arrest at high cell density. However, only a few reports described the dynamic behavior of transcription factors involved in this process. In this study, we showed that the mRNA levels of plasminogen activator inhibitor type 1 (PAI-1) decreased drastically at high cell density, and that ELK3, a member of the Ets transcription factor family, repressed PAI-1 expression. We also demonstrated that while ELK3 was distributed evenly throughout the cell at low cell density, it accumulated in the nucleus at high cell density, and that binding of DNA by ELK3 at the A domain facilitated its nuclear accumulation. Furthermore, we found that ETS1, a PAI-1 activator, occupied the ELK3-binding site within the PAI-1 promoter at low cell density, while it was released at high cell density. These results suggest that at high cell density, the switching of binding of transcription factors from ETS1 to ELK3 occurs at a specific binding site of the PAI-1 promoter, leading to the cell-density dependent suppression of PAI-1 expression.

Knock-down of plasminogen-activator inhibitor-1 enhances expression of E-cadherin and promotes epithelial differentiation of human pancreatic adenocarcinoma cells

High levels of plasminogen activator inhibitor-1 (PAI-1), which is produced by stromal, endothelial, and cancer cells and has multiple complex effects on cancers, correlate with poor cancer prognosis. To more definitively study the role of endogenously produced PAI-1 in human pancreatic adenocarcinoma (PAC) PANC-1 cell line biology, we used anti-PAI-1 shRNA to create stable PAI-1 deficient cells (PD-PANC-1s). PD-PANC-1s exhibited a heterogeneous morphology. While the majority of cells exhibited a cuboidal shape similar to the parental PANC-1 or the vector-infected control cells, numerous large cells with long filopodia and a neuronal-like appearance were observed. Although both Vector-control cells and PD-PANC-1s expressed mRNAs that are characteristic of mesenchymal, neural, and epithelial phenotypes, epithelial marker RNAs were up-regulated (e.g., E-cadherin, 32-fold) whereas mesenchymal marker RNAs were down-regulated (e.g., Thy1, ninefold) in PD-PANC-1s, suggesting mesenchymal-to-epithelial transition. Neural markers exhibited both up- and down-regulation. Immunocytochemistry indicated that epithelial-like PD-PANC-1s expressed E-cadherin and β-catenin in significantly more cells, while neural-like cells exhibited robust expression of organized β-3-tubulin. PAI-1 and E-cadherin were rarely co-expressed in the same cells. Indeed, examination of PAI-1 and E-cadherin mRNAs expression in additional cell lines yielded clear inverse correlation. Indeed, infection of Colo357 PAC cells (that exhibit high expression of E-cadherin) with PAI-1-expressing adenovirus led to a marked decrease in E-cadherin expression and to enhanced migration of cells from clusters. Our results suggest that endogenous PAI-1 suppresses expression of E-cadherin and differentiation in PAC cells in vitro, supporting its negative impact on tumor prognosis.

TLS-CHOP represses miR-486 expression, inducing upregulation of a metastasis regulator PAI-1 in human myxoid liposarcoma

Myxoid liposarcomas (MLSs) are characterized by t(12;16)(q13;p11) translocation and expression of TLS-CHOP chimeric oncoprotein. However, the molecular functions of TLS-CHOP have not been fully understood. On the other hand, microRNAs (miRNAs) comprise an abundant class of endogenous small non-coding RNAs that negatively regulate the expression of their target genes, and are involved in many biological processes. It is now evident that dysregulation of miRNAs is an important step in the development of many cancers. To our knowledge, however, there have been no reports of the miRNAs involved in MLS tumorigenesis and development. In this study, we have found that miR-486 expression was repressed in TLS-CHOP-expressed NIH3T3 fibroblasts and MLS tissues, and exogenous overexpression of miR-486 repressed growth of MLS cells. Thus, downregulation of miR-486 may be an important process for MLS. In addition, we have identified plasminogen activator inhibitor-1 (PAI-1) as a novel target gene of miR-486. PAI-1 is a unique type of serine protease inhibitor and is known to be one of the key regulators of tumor invasion and metastasis. Furthermore, knockdown of PAI-1 by a specific small interfering RNA (siRNA) inhibited growth of MLS cells, suggesting that increased expression of PAI-1 by miR-486 repression is critical for survival of MLS cells. Collectively, these results suggest a novel essential molecular mechanism that TLS-CHOP activates PAI-1 expression by repression of miR-486 expression in MLS tumorigenesis and development.