Growth factor-dependent activation of the MAPK pathway in human pancreatic cancer: MEK/ERK and p38 MAP kinase interaction in uPA synthesis

The covert symphony: cellular and molecular accomplices in breast cancer metastasis

Breast cancer has emerged as the most commonly diagnosed cancer and primary cause of cancer-related deaths among women worldwide. Although significant progress has been made in targeting the primary tumor, the effectiveness of systemic treatments to prevent metastasis remains limited. Metastatic disease continues to be the predominant factor leading to fatality in the majority of breast cancer patients. The existence of a prolonged latency period between initial treatment and eventual recurrence in certain patients indicates that tumors can both adapt to and interact with the systemic environment of the host, facilitating and sustaining the progression of the disease. In order to identify potential therapeutic interventions for metastasis, it will be crucial to gain a comprehensive framework surrounding the mechanisms driving the growth, survival, and spread of tumor cells, as well as their interaction with supporting cells of the microenvironment. This review aims to consolidate recent discoveries concerning critical aspects of breast cancer metastasis, encompassing the intricate network of cells, molecules, and physical factors that contribute to metastasis, as well as the molecular mechanisms governing cancer dormancy.

Functional network analysis reveals potential repurposing of β-blocker atenolol for pancreatic cancer therapy

BACKGROUND

The survival rate of patients with pancreatic cancer is low; therefore, continuous discovery and development of novel pancreatic cancer drugs are required. Functional network analysis is an integrated bioinformatics approach based on gene, target, and disease networks interaction, and it is extensively used in drug discovery and development.

OBJECTIVE

This study aimed to identify if atenolol, a selective adrenergic inhibitor, can be repurposed for the treatment of pancreatic cancer using functional network analysis.

METHODS

Direct target proteins (DTPs) and indirect target proteins (ITPs) were obtained from STITCH and STRING databases, respectively. Atenolol-mediated proteins (AMPs) were collected from DTPs and ITPs and further analyzed for gene ontology, KEGG pathway enrichment, genetic alterations, overall survival, and molecular docking.

RESULTS

We obtained 176 AMPs that consisted of 10 DTPs and 166 ITPs. Among the AMPs involved in the pancreatic cancer pathways, several AMPs such as MAPK1, RELA, MAPK8, STAT1, and STAT3 were identified. Genetic alterations in seven AMPs were identified in 0.9%-16% of patients. Patients with high mRNA levels of MAPK1, RELA, STAT3, GNB1, and MMP9 had significantly worse overall survival rates compared with patients with low expression. Molecular docking studies showed that RELA and MMP9 are potential target candidates of atenolol in the treatment of patients with pancreatic cancer.

CONCLUSION

In conclusion, atenolol can potentially be repurposed to target pancreatic cancer cells by modulating MMP9 and NF-κB signaling. The results of this study need to be further validated in vitro and in vivo.

The Function of the HGF/c-Met Axis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, leading to a large global cancer burden. Hepatocyte growth factor (HGF) and its high-affinity receptor, mesenchymal epithelial transition factor (c-Met), are closely related to the onset, progression, and metastasis of multiple tumors. The HGF/c-Met axis is involved in cell proliferation, movement, differentiation, invasion, angiogenesis, and apoptosis by activating multiple downstream signaling pathways. In this review, we focus on the function of the HGF/c-Met axis in HCC. The HGF/c-Met axis promotes the onset, proliferation, invasion, and metastasis of HCC. Moreover, it can serve as a biomarker for diagnosis and prognosis, as well as a therapeutic target for HCC. In addition, it is closely related to drug resistance during HCC treatment.

Increased expression of hematological and neurological expressed 1 (HN1) is associated with a poor prognosis of hepatocellular carcinoma and its knockdown inhibits cell growth and migration partly by down-regulation of c-Met

Hematologic and neurological expression 1 (HN1) has been reported to involved in certain cancers, but its role in hepatocellular carcinoma (HCC) is largely unknown. The contribution of HN1 to HCC progression was investigated in the present study. We found that HN1 was significantly up-regulated in HCC tissues, compared with normal tissues, by analyzing the Oncomine and Human Protein Atlas database; and found that high expression of HN1 was markedly associated with worse overall survival, relapse-free survival, progression- free survival and disease-specific survival in HCC patients via exploring the Kaplan-Meier plotter database. Functional assays revealed that HN1 knockdown by siRNA induced G1 cell cycle arrest, and inhibited the growth and migration of HCC cells; accordingly, HN1 over-expression promoted HCC cells proliferation and migration. Further studies indicated that HN1 knockdown reduced the expression of cyclin D1 and CDK4, while upregulated the cell cycle inhibitor p21WAF1/Cip1. Moreover, HN1 knockdown decreased c-Met (receptor tyrosine kinase of hepatocyte growth factor) expression, and suppressed ERK activation, which is a common downstream signaling pathway triggered by c-Met; consistently, HN1 over-expression reversed these effects. Meanwhile, down-regulation of c-Met partly eliminated the effect of HN1 over-expression in HCC cells. Thus, the present findings suggested that HN1 promotes the progression of HCC to some extent by up-regulating the expression of c-Met, and may act as a potential biomarker and therapeutic target for the treatment of HCC.

Potential Mechanisms of Action of Dietary Phytochemicals for Cancer Prevention by Targeting Cellular Signaling Transduction Pathways

Cancer is a severe health problem that significantly undermines life span and quality. Dietary approach helps provide preventive, nontoxic, and economical strategies against cancer. Increased intake of fruits, vegetables, and whole grains are linked to reduced risk of cancer and other chronic diseases. The anticancer activities of plant-based foods are related to the actions of phytochemicals. One potential mechanism of action of anticancer phytochemicals is that they regulate cellular signal transduction pathways and hence affects cancer cell behaviors such as proliferation, apoptosis, and invasion. Recent publications have reported phytochemicals to have anticancer activities through targeting a wide variety of cell signaling pathways at different levels, such as transcriptional or post-transcriptional regulation, protein activation and intercellular messaging. In this review, we discuss major groups of phytochemicals and their regulation on cell signaling transduction against carcinogenesis via key participators, such as Nrf2, CYP450, MAPK, Akt, JAK/STAT, Wnt/β-catenin, p53, NF-κB, and cancer-related miRNAs.

Cellular Mechanisms of Hepatocyte Growth Factor-Mediated Urokinase Plasminogen Activator Secretion by MAPK Signaling in Hepatocellular Carcinoma

Aims and Background

The hepatocyte growth factor, its receptor c-Met, and urokinase-type plasminogen mediate various cellular responses on activation, including proliferation, survival, invasion, and metastasis. The regulatory mechanisms for the proliferation and the particular invasive phenotypes of hepatocellular carcinoma are not yet fully understood. In order to clarify the intracellular downstream signal for hepatocyte growth factor/c-Met signaling in tumor progression and metastasis in hepatoma, we determined the effects of a specific MEK1 inhibitor (PD 098059) and a p38 kinase inhibitor (SB 203580) on hepatocyte growth factor-mediated cell proliferation and urokinase-type plasminogen expression in hepatoma cell lines (HepG2 and Hep3B).

Results

Hepatocyte growth factor treatment induced the phosphorylation of ERK and p38 kinase in a dose-dependent manner, resulting in an early peak of phosphorylation at 3 to 10 min, which then rapidly decreased to a near basal level. Pretreatment with PD 098059 reduced hepatocyte growth factor-mediated cell proliferation and urokinase-type plasminogen secretion. In contrast, SB 203580 pretreatment enhanced cell proliferation and urokinase-type plasminogen secretion due to induction of ERK phosphorylation. Treatment with PD 098059 and SB 203580 resulted in a decrease in phospho-ERK activity. Stable expression of dominant negative-MEK1 in HepG2 cells showed a decrease in hepatocyte growth factor-mediated urokinase-type plasminogen secretion.

Conclusions

Such results suggest that interaction of an MEK/ERK and a p38 kinase might be critical in intrahepatic invasion and metastasis of human hepatoma cells.

Diversity and functional evolution of the plasminogen activator system

The urokinase plasminogen activator system is a family of serine proteases which consists of uPA (urokinase plasminogen activator), uPAR (urokinase type plasminogen activator receptor) and PAI-1 (plasminogen activator inhibitor 1). In addition to their significant roles in activation, these proteases act as key regulators of the tumor microenvironment and are involved in the metastatic process in many cancers. High levels of uPA system proteases in many human cancer predicts poor patient prognosis and strongly indicated a key role of uPA system in cancer metastasis. Individual components of uPA system are found to be differentially expressed in cancer cells compared to normal cells and therefore are potential therapeutic targets. In this review, we present the molecular and cellular mechanisms underlying the role of uPA system in cancer progression. Epithelial to mesenchymal transitions (EMT) is the main cause of the cancer cell metastasis. We have also attempted to relate the role of uPA signaling in EMT of cancer cells.

The Therapeutic Targeting of HGF/c-Met Signaling in Hepatocellular Carcinoma: Alternative Approaches

The poor prognosis of hepatocellular carcinoma (HCC), one of the most devastating cancers worldwide, is due to frequent recurrence and metastasis. Among the metastatic factors in the tumor microenvironment, hepatocyte growth factor (HGF) has been well known to play critical roles in tumor progression, including HCC. Therefore, c-Met is now regarded as the most promising therapeutic target for the treatment of HCC. However, there are still concerns about resistance and the side effects of using conventional inhibitors of c-Met, such as tyrosine kinase inhibitors. Recently, many alternative strategies of c-Met targeting have been emerging. These include targeting the downstream effectors of c-Met, such as hydrogen peroxide-inducible clone 5 (Hic-5), to block the reactive oxygen species (ROS)-mediated signaling for HCC progression. Also, inhibition of endosomal regulators, such as PKCε and GGA3, may perturb the c-Met endosomal signaling for HCC cell migration. On the other hand, many herbal antagonists of c-Met-dependent signaling, such as saponin, resveratrol, and LZ-8, were identified. Taken together, it can be anticipated that more effective and safer c-Met targeting strategies for preventing HCC progression can be established in the future.

Thrombosis recanalization by paeoniflorin through the upregulation of urokinase‑type plasminogen activator via the MAPK signaling pathway

Paeoniflorin, the major component of Paeonia lactiflora pall, has previously been reported to prevent thrombosis. Plasminogen activator urokinase (uPA) is a serine protease that markedly facilitates normal thrombosis resolution. Paeoniflorin and uPA have been linked to the mitogen-activated protein kinase (MAPK) signaling pathway. In the current study, the influence of paeoniflorin on the expression of uPA was investigated and the underlying regulatory mechanism was preliminarily determined. The prothrombotic state of the model animals treated with paeoniflorin were assessed by enzyme-linked immunosorbent assay (ELISA). Additionally, the cytotoxicity of paeoniflorin on human umbilical vein endothelial cell (HUVEC) cultures was estimated using a methyl thiazolyl tetrazolium assay and the possible pathways involved in the interaction between paeoniflorin and uPA were evaluated using western blot analysis. The ELISA results demonstrated that the levels of 6-keto prostaglandin F_1a, fibronectin and uPA were significantly upregulated by treatment with paeoniflorin compared with control (P<0.05). By contrast, the expression of fibrinogen, D-dimer and thromboxane B₂ were inhibited. With an increase in the concentration of paeoniflorin the cell viability of HUVECs decreased gradually. The results of western blot analysis demonstrated that paeoniflorin increased the phosphorylation of MAPK 14 (p38) and MAPK 8 (JNK). The present study demonstrated that paeoniflorin has the potential to improve the prethrombotic state and recanalize thrombosis by increasing the expression of uPA, which may be mediated via regulation of the p38 and JNK MAPK signaling pathways. However, this treatment effect was dependent on the concentration of paeoniflorin used, an unsuitable concentration of the agent would result in a negative effect on the anti-thrombosis pathways.

Synergistic effect of combinatorial treatment with curcumin and mitomycin C on the induction of apoptosis of breast cancer cells: a cDNA microarray analysis

In order to explore the synergistic mechanisms of combinatorial treatment using curcumin and mitomycin C (MMC) for breast cancer, MCF-7 breast cancer xenografts were conducted to observe the synergistic effect of combinatorial treatment using curcumin and MMC at various dosages. The synergistic mechanisms of combinatorial treatment using curcumin and MMC on the inhibition of tumor growth were explored by differential gene expression profile, gene ontology (GO), ingenuity pathway analysis (IPA) and Signal-Net network analysis. The expression levels of selected genes identified by cDNA microarray expression profiling were validated by quantitative RT-PCR (qRT-PCR) and Western blot analysis. Effect of combinatorial treatment on the inhibition of cell growth was observed by MTT assay. Apoptosis was detected by flow cytometric analysis and Hoechst 33258 staining. The combinatorial treatment of 100 mg/kg curcumin and 1.5 mg/kg MMC revealed synergistic inhibition on tumor growth. Among 1501 differentially expressed genes, the expression of 25 genes exhibited an obvious change and a significant difference in 27 signal pathways was observed (p<0.05). In addition, Mapk1 (ERK) and Mapk14 (MAPK p38) had more cross-interactions with other genes and revealed an increase in expression by 8.14- and 11.84-fold, respectively during the combinatorial treatment by curcumin and MMC when compared with the control. Moreover, curcumin can synergistically improve tumoricidal effect of MMC in another human breast cancer MDA-MB-231 cells. Apoptosis was significantly induced by the combinatorial treatment (p<0.05) and significantly inhibited by ERK inhibitor (PD98059) in MCF-7 cells (p<0.05). The synergistic effect of combinatorial treatment by curcumin and MMC on the induction of apoptosis in breast cancer cells may be via the ERK pathway.

Terminalia catappa attenuates urokinase-type plasminogen activator expression through Erk pathways in Hepatocellular carcinoma

Background

The survival rate of malignant tumors, and especially hepatocellular carcinoma (HCC), has not improved primarily because of uncontrolled metastasis. In our previous studies, we have reported that Terminalia catappa leaf extract (TCE) exerts antimetastasis effects on HCC cells. However, the molecular mechanisms of urokinase-type plasminogen activator (u-PA) in HCC metastasis have not been thoroughly investigated, and remain poorly understood.

Methods

The activities and protein levels of u-PA were determined by casein zymography and western blotting. Transcriptional levels of u-PA were detected by real-time PCR and promoter assays.

Results

We found that treatment of Huh7 cells with TCE significantly reduced the activities, protein levels and mRNA levels of u-PA. A chromatin immunoprecipitation (ChIP) assay showed that TCE inhibited the transcription protein of nuclear factors SP-1 and NF-κB. TCE also did inhibit the effects of u-PA by reducing the phosphorylation of ERK1/2 pathway.

Conclusions

These results show that u-PA expression may be a potent therapeutic target in the TCE-mediated suppression of HCC metastasis.

RY10-4 suppressed metastasis of MDA-MB-231 by stabilizing ECM and E-cadherin

In the article, we investigated the anti-metastasis mechanism of RY10-4, an anti-tumor compound derived from protoapigenone, in breast tumor cells MB-MDA-231. The analog of protoapigenone with an unaromatic B-ring was verified to suppress the proliferation of several tumor cells by previous research that also showed that several tumor progression such as inducing apoptosis and anti-angiogenesis could be acted on by RY10-4. In the article, we investigated the mechanism about how RY10-4 suppressed the invasion of MDA-MB-231. Firstly, the transwells assays with and without matrigel were adapted to evaluate the anti-metastasis and anti-invasion activity. Much research had demonstrated that the ECM and E-cadherin/β-catenin complex play an important role in cell adhesion and the formation of the cell skeleton, and as we knew the abnormal and absent expression of ECM and E-cadherin/β-catenin complex are found in many malignant cells. The result demonstrated that the amount and distribution of E-cadherin/β-catenin complex were backed on track by RY10-4, and the expression of MMP-2/9 in MDA-MB-231, which functions as a major negative factor of ECM, was down-regulated after co-cultured with RY10-4. Furthermore the pathway related to MMP-2/9 and E-cadherin was assessed by the western blot. As the results showed, the MAPK pathway and the spread of β-catenin were affected by RY10-4 to exert the anti-metastasis on MDA-MB-231. Collectively, the research revealed a novel anti-tumor ability of RY10-4 by inhibiting migration and invasion in MDA-MB-231.

Gelatinase B/MMP-9 in Tumour Pathogenesis and Progression

Since its original identification as a leukocyte gelatinase/type V collagenase and tumour type IV collagenase, gelatinase B/matrix metalloproteinase (MMP)-9 is now recognised as playing a central role in many aspects of tumour progression. In this review, we relate current concepts concerning the many ways in which gelatinase B/MMP-9 influences tumour biology. Following a brief outline of the gelatinase B/MMP-9 gene and protein, we analyse the role(s) of gelatinase B/MMP-9 in different phases of the tumorigenic process, and compare the importance of gelatinase B/MMP-9 source in the carcinogenic process. What becomes apparent is the importance of inflammatory cell-derived gelatinase B/MMP-9 in tumour promotion, early progression and triggering of the "angiogenic switch", the integral relationship between inflammatory, stromal and tumour components with respect to gelatinase B/MMP-9 production and activation, and the fundamental role for gelatinase B/MMP-9 in the formation and maintenance of tumour stem cell and metastatic niches. It is also apparent that gelatinase B/MMP-9 plays important tumour suppressing functions, producing endogenous angiogenesis inhibitors, promoting inflammatory anti-tumour activity, and inducing apoptosis. The fundamental roles of gelatinase B/MMP-9 in cancer biology underpins the need for specific therapeutic inhibitors of gelatinase B/MMP-9 function, the use of which must take into account and substitute for tumour-suppressing gelatinase B/MMP-9 activity and also limit inhibition of physiological gelatinase B/MMP-9 function.

The urokinase plasminogen activator system in breast cancer invasion and metastasis

The urokinase plasminogen activator system, which is a serine protease family include urokinase-type plasminogen activator (uPA), the uPA receptor and plasminogen activator inhibitors (PAIs). uPA catalyzes the transformation of plasminogen to its active form plasmin, which is able to degrade the extracellular matrix (ECM) and basement membranes, directly or indirectly through activating pro-matrix metalloproteinases (pro-MMPs), promoting cancer cell metastasis and invasion. Both uPA and PAI-1 are poor prognosis markers in primary breast cancer. Evidence has been presented that the uPA system facilitates breast cancer metastasis by several different mechanisms, such as the Ras-ERK pathway and p38 MAPK pathway. This review focuses on uPA system, summarizes their biological effects, highlights the molecular mechanism and pathway, and discusses the role of uPA system in the prevention and treatment of human breast cancers.

Isoproterenol modulates matrix metalloproteinase-2 (MMP-2) and its tissue inhibitor-2 (TIMP-2) in rat parotid gland

OBJECTIVE

Chronic isoproterenol treatment causes hypertrophy and hyperplasia of rodent salivary glands. Cell-extracellular matrix interactions play a critical role in salivary gland proliferation and matrix metalloproteinases (MMPs) are known to be involved in cell proliferation. The present study was undertaken to investigate the expression of MMP-2 and the tissue inhibitor metalloproteinase (TIMP)-2 in rat parotid gland following isoproterenol treatment.

DESIGN

Female Wistar rats were daily treated with isoproterenol (25mg/kg body weight) for 0, 1, 3, and 7 days. Expression of parotid gland MMP-2 and its tissue inhibitor TIMP-2 was analysed by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTS

Our results suggest that isoproterenol modulates expression of MMP-2 and TIMP-2 mRNAs, as well as their protein expression levels in a time dependent-manner. Interestingly, at day 1 of treatment, MMP-2 and TIMP-2 expression were higher in comparison to untreated gland. At days 3 and 7, we can observe a gradual decrease of mRNA and protein levels of MMP-2 and TIMP-2.

CONCLUSIONS

Our results suggest the presence of a isoproterenol-dependent modulation of extracellular matrix components. Such a modulation seems to be associated with β-adrenergic agonist-induced hyperplasy, occurring during the first 24h of agonist treatment, and hypertrophy of the parotid gland.

Antimetastatic effects and mechanisms of apo-8'-lycopenal, an enzymatic metabolite of lycopene, against human hepatocarcinoma SK-Hep-1 cells

Lycopene is primarily metabolized by carotenoid monoxygenase II into apo-8'- and apo-12'-lycopenal in the rat liver. Although lycopene possesses antimetastatic activity in a highly invasive hepatoma SK-Hep-1 cell line, little is known whether its metabolites have a similar effect. In this study, we investigated the antimetastatic effects of apo-8'-lycopenal (1-10 μM) in comparison with lycopene (10 μM) in SK-Hep-1 cells. We found that both apo-8'-lycopenal and lycopene inhibited the invasion and migration of SK-Hep-1 cells, and the effect of apo-8'-lycopenal was stronger than that of lycopene at the same concentration (10 μM). Mechanistically, apo-8'-lycopenal: 1) decreased the activities and protein expression of metalloproteinase-2 (MMP-2) and -9; 2) increased the protein expression of nm23-H1 and the tissue inhibitor of MMP (TIMP)-1 and -2; 3) suppressed protein expression of Rho small GTPases; and 4) inhibited focal adhesion kinase-mediated signaling pathway, such as ERK/p38 and PI3K-Akt axis. Overall, these results demonstrate that apo-8'-lycopenal possesses antimetastatic activity in SK-Hep-1 cells and that this effect is stronger than that of lycopene, suggesting that the antimetastatic effect may be attributed, at least in part, to its metabolites such as apo-8'-lycopenal.

HGF/c-Met overexpressions, but not met mutation, correlates with progression of non-small cell lung cancer

Hepatocyte Growth Factor (HGF) and its receptor c-Met are suggested to play an important role in progression of solid organ tumors by mediating cell motility, invasion and metastasis. Overexpression of HGF and c-Met have been shown in non-small-cell lung cancer (NSCLC). However, their role in tumor progression is not clearly defined. The aim of this study is to determine the role of HGF/c-Met pathway and its association with invasion related markers and clinicopathologic parameters in NSCLC. Immunohistochemical analysis was performed on 63 paraffin-embedded NSCLC tumor sections. The expressions of invasion related markers such as Matrix Metalloproteinases (MMPs) 2 and 9, Tissue Inhibitor Metalloproteinase (TIMP) 1 and 3 and RhoA were also examined. Co-expression of HGF/c-Met was significantly associated with lymph node invasion and TIMP-3 and RhoA overexpressions. There were positive correlation between TIMP-3 overexpression and advanced stage and negative correlation between RhoA overexpression and survival. DNA sequencing for Met mutations in both nonkinase and tyrosine kinase (TK) domain was established. A single nucleotide polymorphism (SNP) in sema domain and two SNPs in TK domain of c-Met were found. There was no statistically significant correlation between the presence of c-Met alterations and clinicopathologic parameters except shorter survival time in cases with two SNPs in TK domain. These results suggest that HGF/c-Met might exert their effects in tumor progression in association with RhoA and probably with TIMP-3. The blockade of the HGF/c-Met pathway with RhoA and/or TIMP-3 inhibitors may be an effective therapeutic target for NSCLC treatment.

High-throughput RNAi screening identifies a role for TNK1 in growth and survival of pancreatic cancer cells

To identify novel targets in pancreatic cancer cells, we used high-throughput RNAi (HT-RNAi) to select genes that, when silenced, would decrease viability of pancreatic cancer cells. The HT-RNAi screen involved reverse transfecting the pancreatic cancer cell line BxPC3 with a siRNA library targeting 572 kinases. From replicate screens, approximately 32 kinases were designated as hits, of which 22 kinase targets were selected for confirmation and validation. One kinase identified as a hit from this screen was tyrosine kinase nonreceptor 1 (TNK1), a kinase previously identified as having tumor suppressor-like properties in embryonic stem cells. Silencing of TNK1 with siRNA showed reduced proliferation in a panel of pancreatic cancer cell lines. Furthermore, we showed that silencing of TNK1 led to increased apoptosis through a caspase-dependent pathway and that targeting TNK1 with siRNA can synergize with gemcitabine treatment. Despite previous reports that TNK1 affects Ras and NF-κB signaling, we did not find similar correlations with these pathways in pancreatic cancer cells. Our results suggest that TNK1 in pancreatic cancer cells does not possess the same tumor suppressor properties seen in embryonic cells but seems to be involved in growth and survival. The application of functional genomics by using HT-RNAi screens has allowed us to identify TNK1 as a growth-associated kinase in pancreatic cancer cells.

Carbonic anhydrase XII promotes invasion and migration ability of MDA-MB-231 breast cancer cells through the p38 MAPK signaling pathway

Carbonic anhydrase (CA) XII, an extracellular enzyme involved in the regulation of the microenvironment acidity and tumor malignant phenotype, was originally identified as a protein overexpressed in some types of cancers, including breast cancer. However, the cellular function and mechanism of CAXII remained unclear. In this study, the effects of CAXII expression on invasion and migration of breast cancer cells was investigated. Gene knockdown of CAXII in the human breast cancer cell line MDA-MB-231 resulted in decreased invasion and migration by interfering with the p38 MAPK pathway. CAXII knockdown also decreased the expression of matrix metalloproteinase (MMP)-2, MMP-9, and urokinase-type plasminogen activator (u-PA), but increased tissue inhibitor of metalloproteinases (TIMP)-2 and plasminogen activator inhibitor (PAI)-1 expression. Furthermore, decreased invasive and migration ability of CAXII-knockdown cells were restored by an overexpression of CAXII. Results also showed that CAXII knockdown may decrease anchorage-independent growth and cell growth by inhibiting CDK6 and cyclin D1 expression. Furthermore, the impact of CAXII knockdown on invasion, migration and cell growth was further evidenced by effects on tumor size and metastasis of MDA-MB-231 cells in vivo. Taken together, these data suggested that CAXII may affect the capability of invasion and migration of MDA-MB-231 cells, which may be mediated through the p38 MAPK pathway.

Curcumin reduced the side effects of mitomycin C by inhibiting GRP58-mediated DNA cross-linking in MCF-7 breast cancer xenografts

Mitomycin C (MMC), a chemotherapeutic agent in breast cancer treatments, inhibits tumor growth through DNA cross-linking and breaking, but it has severe side effects. Here we examined whether and how curcumin reduced the side effects of MMC. We found that combination treatment with MMC and curcumin reduced tumor weight by 70% and 36% compared with saline and curcumin-treated groups, respectively. The combination treatment reduced weight loss and improved kidney function and bone marrow suppression compared with MMC treatment alone. Moreover, the combination treatment inhibited glucose regulatory protein (GRP58)-mediated DNA cross-linking. The combination treatment inhibited GRP58 through the ERK/p38 MAPK pathway. In conclusion, the current study provided evidence that MMC and curcumin combination treatment reduced MMC side effects by inhibiting GRP58-mediated DNA cross-linking through the ERK/p38 MAPK pathway.

Analysis of the pancreatic tumor progression by a quantitative proteomic approach and immunhistochemical validation

To increase the knowledge about the development of pancreatic ductal adenocarcinoma, (PDAC) detailed analysis of the tumor progression is required. To identify proteins differentially expressed in the pancreatic intraepithelial neoplasia (PanIN), the precursor lesions of PDAC, we conducted a quantitative proteome study on microdissected PanIN cells. Proteins from 1000 microdissected cells were subjected to a procedure combining fluorescence dye saturation labeling with high resolution two-dimensional gel electrophoresis (2-DE). Differentially regulated protein spots were identified using protein lysates from PDAC tissues as a reference proteome followed by nanoLC-ESI-MS/MS. Thirty-seven single lesions of different PanIN grade (PanIN 1A/B, PanIN 2, PanIN 3) from nine patients were analyzed. Their protein expression was compared with each other, with PDAC cells and with normal ductal cells. The differential expression of differentially regulated protein spots was validated by means of immunohistochemistry using tissue microarrays. Of 2500 protein spots, 86 were found to be significantly regulated (p < 0.05, ratio > 1.6) during PanIN progression. Thirty-one nonredundant proteins were identified by mass spectrometry. Immunohistochemistry revealed that the differential expression of the selected candidate proteins major vault protein (MVP), anterior gradient 2 (AGR 2) and 14-3-3 sigma, annexin A4, and S100A10 could be successfully validated in PanIN lesions. The highly sensitive and robust proteome analysis revealed differentially regulated proteins involved in pancreatic tumor progression. The analysis of normal preneoplastic and neoplastic pancreatic tissue establishes a basis for identification of candidate biomarkers in PanIN progression that can be detected in pancreatic juice and in serum or are candidates for in vivo imaging approaches.

Reactive oxygen species regulate urokinase plasminogen activator expression and cell invasion via mitogen-activated protein kinase pathways after treatment with hepatocyte growth factor in stomach cancer cells

Background

Reactive oxygen species (ROS) are closely associated with the intracellular signal cascade, thus strongly implicating involvement in tumor progression. However, the mechanism by which ROS are generated and how ROS target downstream molecules to trigger tumor metastasis is unclear. In this study, we investigated the underlying signal pathways in ROS-induced urokinase plasminogen activator (uPA) expression in the human gastric cancer cells, NUGC-3 and MKN-28.

Methods and Results

Intracellular ROS, as determined using the fluorescent probe, 2'-7' dichlorofluorescein diacetate, decreased after treatment with hepatocyte growth factor (HGF). We confirmed that Rac-1 regulated ROS production after activation of the AKT pathway with HGF. Exogenously added H₂O₂ promoted the expression of HGF, but not in a dose-dependent manner and also showed negative expression of HGF after co-treatment with H₂O₂ and HGF. Treatment with NAC, an intracellular free radical scavenger, decreased the enhancement of uPA production and tumor invasion in both cells. We clarified the downstream pathways regulated by ROS after treatment with H₂O₂, which showed negative control between FRK and p38 kinase activities for uPA regulation.

Conclusion

HGF regulates Rac-1-induced ROS production through the Akt pathway and ROS regulates uPA production and invasion via MAP kinase, which provides novel insight into the mechanisms underlying the progression of gastric cancer.

Identification of novel alternative splice isoforms of circulating proteins in a mouse model of human pancreatic cancer

To assess the potential of tumor-associated, alternatively spliced gene products as a source of biomarkers in biological fluids, we have analyzed a large data set of mass spectra derived from the plasma proteome of a mouse model of human pancreatic ductal adenocarcinoma. MS/MS spectra were interrogated for novel splice isoforms using a nonredundant database containing an exhaustive three-frame translation of Ensembl transcripts and gene models from ECgene. This integrated analysis identified 420 distinct splice isoforms, of which 92 did not match any previously annotated mouse protein sequence. We chose seven of those novel variants for validation by reverse transcription-PCR. The results were concordant with the proteomic analysis. All seven novel peptides were successfully amplified in pancreas specimens from both wild-type and mutant mice. Isotopic labeling of cysteine-containing peptides from tumor-bearing mice and wild-type controls enabled relative quantification of the proteins. Differential expression between tumor-bearing and control mice was notable for peptides from novel variants of muscle pyruvate kinase, malate dehydrogenase 1, glyceraldehyde-3-phosphate dehydrogenase, proteoglycan 4, minichromosome maintenance, complex component 9, high mobility group box 2, and hepatocyte growth factor activator. Our results show that, in a mouse model for human pancreatic cancer, novel and differentially expressed alternative splice isoforms are detectable in plasma and may be a source of candidate biomarkers.

Involvement of protein kinase C beta-extracellular signal-regulating kinase 1/2/p38 mitogen-activated protein kinase-heat shock protein 27 activation in hepatocellular carcinoma cell motility and invasion

To understand the molecular mechanism that underlies the role of various prominent signal pathways in hepatocellular carcinoma (HCC) metastasis, a human signal transduction oligonucleotide microarray analysis was carried out in cultured HCC cell models with increasing spontaneous metastatic potential (MHCC97L, MHCC97H, and HCCLM6). The results revealed that the mitogen-activated protein kinase (MAPK) pathway is the prominently upregulated pathway in HCC metastasis. Further study showed that basal phosphorylated levels of extracellular signal-regulating kinase (ERK)(1/2) and p38 MAPK consecutively increased from MHCC97L to MHCC97H to HCCLM6 cells, but not c-Jun N-terminal kinase. The phosphorylation of ERK(1/2) and p38 MAPK was regulated by upregulated protein kinase C beta (PKC beta) in HCC cells through the integrated use of PKC beta RNA interference, the PKC beta specific inhibitor enzastaurin and a PKC activator phorbol-12-myristate-13-acetate. Heat shock protein 27 (HSP27) was also verified as a downstream common activated protein of PKC beta-ERK(1/2) and PKC beta-p38 MAPK. In vitro migration and invasion assay further showed that the depletion of PKC beta or inhibition of PKC beta activation effectively decreased HCC cell motility and invasion. Moreover, the motility and invasion of phorbol-12-myristate-13-acetate-stimulated PKC beta-mediated HCC cells was significantly negated by an ERK inhibitor, 1.4-diamino-2.3-dicyano-1.4-bis[2-aminophenylthio] butadiene, or a p38 MAPK inhibitor, 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole. It also showed that HSP27 is critical in PKC beta-mediated HCC cell motility and invasion. Taken together, this study reveals the important role of this PKC beta-ERK(1/2)/p38MAPK-HSP27 pathway, which was verified for the first time, in modulating HCC cell motility and invasion.

Role of p38 mapk on the down-regulation of matrix metallo-proteinase-9 expression in rat astrocytes

In spite of their pathophysiological importance in neuro-inflammatory diseases, little is known about the signal transduction pathways that lead to the induction of matrix metalloproteinases (MMPs) in the central nervous system. We reported previously that lipopolysaccharide (LPS) induced MMP-9 expression through ERK1/2 pathway in rat primary astrocytes (Glia 41:15-24, 2003). Here, we investigated the role of other MAPK pathways, including p38 and JNK/SAPK, on the regulation of MMP-9 expression in LPS-stimulated rat primary astrocytes. LPS activated both p38 and JNK in astrocytes. Treatment with a specific p38 MAPK inhibitor SB203580, but not JNK inhibitor SP600125, increased the LPS-stimulated MMP-9 expression in a concentration-dependent manner. Anti-inflammatory cytokines, including IFN-gamma and IL-4, activated p38 MAPK and decreased MMP-9 production in LPS-stimulated astrocytes. When p38 MAPK activation was blocked by SB203580, the inhibitory effects of these cytokines on MMP-9 induction were abolished. Finally, direct injection of SB203580 into the lateral ventricle of rat brain increased the LPS-induced MMP-9 activity in cerebral cortex. Altogether, these results suggest that p38 activation down-regulates the inflammatory stimulation-induced overexpression of MMP-9, both in primary astrocytes and in cerebral cortex. The elaborate interplay between ERK1/2 and p38 pathways provides a more sophisticated mechanism for regulating MMP-9 activity in neuroinflammatory diseases.

The androgen receptor negatively regulates the expression of c-Met: implications for a novel mechanism of prostate cancer progression

The precise molecular mechanisms by which prostate cancer cells progress from androgen-sensitive to androgen-insensitive status still remain largely unclear. The hepatocyte growth factor/scatter factor (HGF/SF) plays a critical role in the regulation of cell growth, cell motility, morphogenesis, and angiogenesis. The aberrant expression of HGF/SF and its receptor, c-Met, often correlates with poor prognosis in a variety of human malignancies, including prostate cancer. Here, we investigate a potential link between androgen signaling and c-Met expression in prostate cancer cells. First, we showed that the androgen receptor (AR) represses the expression of c-Met in a ligand-dependent manner. Using different c-Met promoter/reporter constructs, we identified that Sp1 induces the transcription of c-Met and that AR can repress the Sp1-induced transcription in prostate cancer cells. Moreover, the data from electrophoretic mobility shift assay showed that AR interferes with the interaction between Sp1 and the functional Sp1 binding site within the c-Met promoter. Furthermore, we tested the effect of AR on c-Met expression in an androgen-insensitive prostate cancer cell line, CWR22Rv1. Finally, the repressive role of androgen signaling on c-Met expression was confirmed in prostate cancer xenografts. The above data indicate a dual role of AR in transcriptional regulation. Although the current androgen ablation therapy can repress the expression of growth-promoting genes that are activated by the AR, it may also attenuate the repressive role of AR on c-Met expression. Therefore, the therapeutic strategies to inhibit the activation of the HGF/c-Met pathway may be of benefit when combined with current androgen ablation treatment.

Hepatocyte growth factor installs a survival platform for colorectal cancer cell invasive growth and overcomes p38 MAPK-mediated apoptosis

Hepatocyte growth factor (HGF) induces invasive growth, a biological program that confers tumor cells the capability to invade and metastasize by integrating cell proliferation, motility, morphogenesis, and survival. We here demonstrate that HGFR activation promotes survival of colorectal carcinoma (CRC) cells exposed to conditions that mimic those met during tumor progression, i.e. nutrient deprivation or substrate detachment, and following chemotherapeutic treatment. In all these conditions, a sustained activation of p38 MAPK delivers a main death signal that is overcome by cell treatment with HGF. HGF-driven survival requires the engagement of the PI3K/Akt/mTOR/p70S6K and ERK MAPK transduction pathways. Abrogation of p38 MAPK activity prevents CRC cell apoptosis also when these transduction pathways are inhibited, and treatment with HGF further increases survival. Engagement of these signaling cascades is also needed for HGF to induce CRC cell scattering, morphogenesis, motility and invasion. Activation of p38 MAPK signaling is therefore a main apoptotic switch for CRC cells in the stressful conditions encountered during tumor progression. Conversely, HGF orchestrates several biochemical pathways, which allow cell survival in these same conditions and promote the biological responses required for tumor invasive growth. Both p38 MAPK and HGF/HGFR signaling constitute potential molecular targets for inhibiting colorectal carcinogenesis.

Activation of c-jun N-terminal kinase is associated with cell proliferation and shorter relapse-free period in superficial spreading malignant melanoma

Signaling pathways regulating cell proliferation and survival have become attractive targets for anticancer strategies. In the present study, we analyzed by immunohistochemistry, a panel of benign nevi, superficial spreading and nodular primary melanomas and metastases for expression of activated p38/mitogen-activated protein kinase (p-p38) and c-jun N-terminal kinase (JNK) (p-JNK) and correlated the findings with known prognostic variables. Twenty-five and 35% of the primaries and 9 and 25% of the metastases expressed variable levels of p-p38 and p-JNK, respectively. In benign nevi, 73.5% expressed p-JNK and 7% expressed p-p38. For patients with superficial spreading melanomas, high level of cytoplasmic p-JNK was associated with thicker tumors (P=0.017) and shorter disease-free survival (P=0.003) as well as with markers of cell proliferation (cyclin A (P=0.017) and p21 (P=0.021)). In nodular melanomas, nuclear p-p38 was associated with Ki-67 (P=0.012), but neither cytoplasmic nor nuclear localized p-p38 was associated with disease outcome. Of note, in superficial spreading melanomas, a positive correlation between cytoplasmic p-JNK and cytoplasmic p-extracellular signal-regulated kinase ERK(1/2) (P=0.005) and p-p38 (P=0.003) was observed. Likewise, p-p38 in cytoplasm was positively associated with cytoplasmic p-ERK1/2 (P<0.0005) and p-Akt (P=0.047). In contrast, except for a positive correlation between nuclear p-p38 and membranous p-TrkA (P=0.02), no correlation between the activation status of the different signaling pathways was observed in nodular melanomas. In conclusion, our results suggest that in benign nevi activated JNK may have a role in restricting uncontrolled cell proliferation or survival. However, during tumor progression, activation of JNK is associated with cell proliferation and shorter relapse-free period for patients with superficial spreading melanomas, suggesting that the JNK activation status could be a marker for clinical outcome in at least a subgroup of malignant melanoma. In contrast, activation of p38 seems to play a less important role in development and progression of malignant melanomas.

Reactive Oxygen Species Mediated Sustained Activation of Protein Kinase C α and Extracellular Signal-Regulated Kinase for Migration of Human Hepatoma Cell Hepg2

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) can trigger growth inhibition, epithelial-mesenchymal transition (EMT)-like cell scattering, and migration of hepatoma cells HepG2 in a protein kinase C-alpha (PKC-alpha)-dependent manner. Saikosaponin a, an ingredient of antitumorigenic Chinese herb Sho-Saiko-to, inhibited cell growth but did not induce EMT-like cell scattering and cell migration of HepG2. Saikosaponin a and TPA induced transient (for 30 minutes) and sustained (until 6 hours) phosphorylation of extracellular signal-regulated kinase (ERK), respectively. Generation of the reactive oxygen species (ROS) was induced by TPA, but not saikosaponin a, for 3 hours. As expected, scavengers of ROS, such as superoxide dismutase, catalase, and mannitol, and the thiol-containing antioxidant N-acetylcystein dramatically suppressed the TPA-triggered cell migration but not growth inhibition of HepG2. The generation of ROS induced by TPA was PKC, but not ERK, dependent. On the other hand, scavengers of ROS and N-acetylcystein also prevented PKC activation and ERK phosphorylation induced by TPA. On the transcriptional level, TPA can induce gene expression of integrins alpha5, alpha6, and beta1 and reduce gene expression of E-cahedrin in a PKC- and ROS-dependent manner. In conclusion, ROS play a central role in mediating TPA-triggered sustained PKC and ERK signaling for regulation of gene expression of integrins and E-cahedrin that are responsible for EMT and migration of HepG2.

Expressions of inducible nitric oxide synthase and matrix metalloproteinase-9 and their effects on angiogenesis and progression of hepatocellular carcinoma

AIM: To determine the expressions of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-9 (MMP-9) in hepatocellular carcinoma (HCC) and to investigate the relationship between iNOS and MMP-9 expression and their effects on angiogenesis and progression of HCC.

METHODS: In this study, we examined iNOS, MMP-9, and CD34 expression in specimens surgically removed from 32 HCC patients and 7 normal liver tissues by immunohistochemical staining. Meanwhile, microvessel density (MVD) was determined as a marker of angiogenesis by counting CD34-positive cells.

RESULTS: The positive rates of iNOS and MMP-9 expression were 71.88% (23/32) and 78.13% (25/32) in HCC. MMP-9 expression was significantly correlated with tumor size, capsule status, TNM stage, and risk of HCC recurrence (P = 0.032, P = 0.033, P = 0.007, and P = 0.001, respectively). There was also a significant relationship between iNOS expression and capsule status and risk of HCC recurrence (P = 0.049 and P = 0.004, respectively), but no correlation between iNOS expression and tumor size and TNM stage. There was a positive association between MVD and TNM stage and risk of HCC recurrence (P = 0.037 and P = 0.000, respectively). The count of MVD was significantly different in different iNOS and MMP-9 immunoreactivity groups (F = 17.713 and 17.097, P = 0.000 and P = 0.000, respectively). The examination of Spearman’s rank correlation coefficient showed that there was a

significant positive correlation between MVD and iNOS, MMP-9 immunoreactivity (r = 0.754 and 0.751, P = 0.000 and P=0.000, respectively). There was also a significant association between MMP-9 and iNOS expression in HCC (P = 0.010).

CONCLUSION: Nitric oxide (NO) produced by iNOS could modulate MMP-9 production and therefore contribute to tumor cell angiogenesis and invasion and metastasis in HCC. The strong expression of iNOS and MMP-9 in HCC may be helpful in evaluating the recurrence of HCC, predicting poor prognosis. For patients with strong expression of MMP-9 and iNOS, the optimal treatment scheme needs to be selected.

Regulation of MMP-9 gene expression for the development of novel molecular targets against cancer and inflammatory diseases

The need to pharmacologically control the proteolytic activity of matrix metalloproteinases (MMPs) has been commonly acknowledged, despite its limited efficacy in clinical trials. Among the reasons that explain this failure is our limited understanding of the signals that control the expression of MMPs in different cell types during different pathological conditions. Thus, future therapies must rely on more selective approaches. With the continually increasing body of proof implicating MMPs in a large number of diseases, it has become a priority to establish the pertinence of molecules involved in the signalling pathways leading to the expression of these enzymes. MMP-9 is a case in point: its dramatic overexpression in cancer and various inflammatory conditions clearly points to the molecular mechanisms controlling its expression as a potential target for eventual rational therapeutic intervention. In this article, recent progress in the signalling pathways that regulate MMP-9 expression is reviewed, and the latest strategies to be considered in the search for a specific inhibitor of its expression are presented.

Matrix metalloproteinases mediate β-adrenergic receptor-stimulated apoptosis in adult rat ventricular myocytes

Changes in the synthesis and activity of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are associated with myocardial remodeling. Here we measured the expression and activity of MMPs and TIMPs, and tested the hypothesis that increased MMP activity plays a proapoptotic role in β-adrenergic receptor (β-AR)-stimulated apoptosis of adult rat ventricular myocytes (ARVMs). β-AR stimulation (isoproterenol, 24 h) increased mRNA levels of MMP-2 and TIMP-1 while it decreased TIMP-2 mRNA levels as analyzed by real-time PCR. Western blot analysis, immunocytochemical analysis, in-gel zymography, and MMP-2 activity assay confirmed β-AR-stimulated increases in MMP-2 protein levels and activity. Inhibition of MMPs using GM-6001 (a broad-spectrum inhibitor of MMPs), SB3CT (inhibitor of MMP-2), and purified TIMP-2 inhibited β-AR-stimulated apoptosis as determined by TdT-mediated dUTP nick end labeling staining. Treatment with active MMP-2 alone increased the number of apoptotic cells. This increase in MMP-2-mediated apoptosis was inhibited by GM-6001 and SB3CT pretreatment. Coimmunoprecipitation studies indicated increased physical association of MMP-2 with β1-integrins after β-AR stimulation. Inhibition of MMP-2 using SB3CT or stimulation of β1-integrin signaling using laminin inhibited the increased association of MMP-2 with β1-integrins. β-AR stimulation increased poly-ADP-ribose-polymerase cleavage, which was inhibited by inhibition of MMP-2. These data suggest the following: 1) β-AR stimulation increases MMP-2 expression and activity and inhibits TIMP-2 expression; 2) inhibition of MMPs, most likely MMP-2, inhibits β-AR-stimulated apoptosis; and 3) the apoptotic effects of MMP-2 may be mediated, at least in part, via its interaction with β1integrins and poly-ADP-ribose-polymerase cleavage.

Involvement of HGF/SF-Met signaling in prostate adenocarcinoma cells: evidence for alternative mechanisms leading to a metastatic phenotype in Pr-14c

BACKGROUND

Hepatocyte growth factor/scatter factor (HGF/SF) facilitates intercellular communication between the epithelial carcinoma and its surrounding stromal tissue during metastatic invasion through interaction with its proto-oncogenic receptor, Met, found on carcinoma cells. This study utilizes the C31/Tag transgenic mouse prostate cancer cell line model in an attempt to characterize the interaction between HGF/SF and Met on the metastatic potential of prostate cancer.

METHODS

Exogenous HGF was supplied to the prostate adenocarcinoma cell line (Pr-14) and metastatic cell line (Pr-14c) to evaluate mitogenicity by proliferation assays, morphological characteristics on an extracellular matrix substrate, and motogenic properties using the scatter assay, invasion chambers, and zymogram studies to analyze secretory enzymes produced by the cell lines.

RESULTS

RNA and protein analyses show that the cell lines express similar amounts of Met. Pr-14 cells have an increased growth rate following HGF/SF treatment, whereas the metastatic Pr-14c cells show little change. Morphological studies of Pr-14c cells on extracellular matrix demonstrate negligible changes when compared to the tubular formation of Pr-14 cells after HGF/SF stimulation. Motility studies of the metastatic cells following HGF/SF treatment reveal a potentially faulty signaling pathway downstream of Met activation in the metastatic prostate cells.

CONCLUSIONS

Our studies suggest that proliferation, invasion, and cell morphological characteristics may be induced independently from the HGF/SF-Met pathway in C31/Tag metastatic prostate cancer cells.

Des-gamma-carboxy prothrombin is a potential autologous growth factor for hepatocellular carcinoma

Des-gamma-carboxyl prothrombin (DCP) is a well recognized tumor marker for hepatocellular carcinoma (HCC). In the present study, we demonstrate that DCP has a mitogenic effect on HCC cell lines. Purified DCP stimulated DNA synthesis of Hep3B and SK-Hep-1 cells in a dose-dependent manner. DCP was found to bind with cell surface receptor Met causing Met autophosphorylation and also to activate STAT3 signaling pathway through Janus kinase 1. Luciferase gene reporter analysis showed that DCP induced STAT3-related transcription. Small interfering RNAs against both STAT3 and Met abrogated DCP-induced cell proliferation. DCP did not affect the mitogen-activated protein kinase pathway, Myc signaling pathway, or phosphoinositide 3-kinase/Akt pathway. Based on these results, we believe that DCP acts as an autologous mitogen for HCC cell lines. The Met-Janus kinase 1-STAT3 signaling pathway may be a major signaling pathway for DCP-induced cell proliferation.

MAPK signal transduction and apoptosis of human gastric carcinoma cells induced by liposomes of survivin antisense oligonucleotide

AIM: To study the relation of mitogen-activated protein kinase (MAPK) signal transduction and apoptosis of human gastric carcinoma cells HS-746T induced by liposomes of survivin antisense oligonucleotide (ASODN).

METHODS: Survivin ASODN was designed and synthesised to transfect human gastric carcinoma cells HS-746T. The cultured cells were divided into 6 groups: vacuity control group, liposome and sense oligonucleotide (SODN) group, 100, 200 and 400 nmoL/L ASODN group and P38MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor groups. Apoptotic index (AI) and proliferative index (PI) were examined by flow cytometry after transfection 2, 4, 8, 12, 24 and 48 h. RT-PCR, immunocytochemical stain, Western blot, immuno-precipitation and kinase activity assay were used to detect protein expression and activity of P38MAPK, ERK1/2, survivin and survivin mRNA after transfection.

RESULTS: Expression of ERK1/2 and P38MAPK has not significantly different among vacuity control group, liposomes group and SODN group. The apoptotic cells increased in anisoconcentration survivin ASODN groups and AI was higher than that of other control group. Apoptotic cells decreased in P38MAPK inhibitor group while increased in ERK1/2. The protein and mRNA expression of survivin decreased when transfection concentration was increased. The phosphorylated and nonphosphorylated ERK1/ 2 showed a dose-and time-dependent decrease whereas protein level of p38MAPK remained unchanged, but activity increased.

CONCLUSION: Survivin ASODN can induce apoptosis of human gastric carcinoma cells in vitro though MAPK signal transduction including activating apoptosis-related signal P38MAPK and suppressing proliferation-related signal ERK1/2.