Expression of survivin in human gastric carcinoma and gastric carcinoma model of rats

Survivin as a potential biomarker for early diagnosis of the progression of precancerous lesions to gastric cancer

BACKGROUND

Gastric cancer is a common cancer developed in a carcinogenesis process from precancerous lesions including chronic gastritis, intestinal metaplasia, and dysplasia. Survivin, an inhibitor-of-apoptosis protein, is associated with the initiation and progression of gastric cancer. The present study aimed to evaluate the immunohistochemical expression patterns of survivin and its relationship with early diagnosis of gastric cancer in Iranian patients.

METHODS

In this retrospective case-control study, immunoexpression of survivin was investigated on sections obtained from formalin-fixed paraffin-embedded tissue blocks of 38 chronic gastritis, 32 intestinal metaplasia, 20 dysplasia, 28 gastric adenocarcinoma, and 22 controls.

RESULTS

Survivin immunoexpression in chronic gastritis was higher than controls, but this difference was not statistically significant (P > 0.05). However, survivin immunoexpression had a steady significant increase from control and chronic gastritis to intestinal metaplasia to dysplasia to gastric adenocarcinoma (P < 0.05). Sensitivity, specificity, and area under the curve of survivin immunohistochemical test for the diagnosis of gastric cancer were 87.5%, 74.4%, and 0.85, respectively. Males had a significantly higher survivin expression than females (P < 0.001). Also, survivin expression was significantly higher in older patients than in younger ones (P < 0.001).

CONCLUSION

It seems that the steady increase in survivin expression from different precancerous lesions to gastric adenocarcinoma suggests that survivin can be used as a potential biomarker for the prevention and early diagnosis of gastric cancer.

Elevated Expressions of Survivin and Endoglin in Patients with Hepatic Carcinoma

OBJECTIVE

To investigate expression profiles of survivin and endoglin in patients with hepatic carcinoma.

MATERIALS AND METHODS

Cancerous tissues (hepatic carcinoma group) of 48 patients with hepatic carcinoma and adjacent noncancerous hepatic tissues (control group) were used as objects of study. Histopathological staining [hematoxylin & eosin (H&E) staining] was used to study the pathological differences in hepatic tissues between hepatic carcinoma group and control group. Moreover, survivin and endoglin protein expressions in hepatic tissues in hepatic carcinoma group and control group were detected via western blotting. Finally, Statistical Product and Service Solutions 17.0 statistical software was used to analyze the differences in survivin and endoglin expressions in hepatic tissues between hepatic carcinoma group and control group.

RESULTS

H&E staining showed that histopathological features in hepatic carcinoma group were significantly different from those in control group. Compared with those in control group, the cell structure in hepatic carcinoma group was damaged, karyopyknosis was obvious, and the hepatic injury was serious. Reverse transcription-polymerase chain reaction showed that survivin and endoglin mRNA expression levels in hepatic carcinoma group were significantly increased compared with those in control group. Besides, immunofluorescence method and western blotting revealed the low expressions of survivin and endoglin proteins in tissues in control group, which were obviously lower than those in hepatic tissues in hepatic carcinoma group. Results of analyses of variance showed that the expressions of survivin and endoglin in normal hepatic tissues and cancerous tissues had statistically significant differences (p < 0.01). Furthermore, expressions of survivin and endoglin were significantly associated with histological grade, tumor size, and tumor, node, metastasis (TNM) stage.

CONCLUSION

Elevated expressions of survivin and endoglin are associated with histological grade, tumor size, and TNM stage in patients with hepatic carcinoma, indicating that survivin and endoglin might be involved in the pathogenesis of hepatic carcinoma and therapeutic targeting them might be a novel approach for the treatment of hepatic carcinoma.

Functional pharmacogenomics and toxicity of PolyPurine Reverse Hoogsteen hairpins directed against survivin in human cells

PolyPurine Reverse Hoogsteen (PPRH) hairpins constitute a relatively new pharmacological agent for gene silencing that has been applied for a growing number of gene targets. Previously we reported that specific PPRHs against the antiapoptotic gene survivin were able to decrease viability of PC3 prostate cancer cells by increasing apoptosis, while not acting on HUVEC non-tumoral cells. These PPRHs were efficient both in vitro and in vivo. In the present work, we performed a functional pharmacogenomics study on the effects of specific and unspecific hairpins against survivin. Incubation of PC3 cells with the specific HpsPr-C-WT led to 244 differentially expressed genes when applying the p < 0.05, FC > 2, Benjamini-Hochberg filtering. Importantly, the unspecific or control Hp-WC did not originate differentially expressed genes using the same settings. Gene Set Enrichment Analysis (GSEA) revealed that the differentially expressed genes clustered very significantly within the gene sets of Regulation of cell proliferation, Cellular response to stress, Apoptosis and Prostate cancer. Network analyses using STRING identified important interacting gene-nodes within the response of PC3 cells to treatment with the PPRH against survivin, mainly POLR2G, PAK1IP1, SMC3, SF3A1, PPARGC1A, NCOA6, UGT2B7, ALG5, VAMP7 and HIST1H2BE, the former six present in the Gene Sets detected in the GSEA. Additionally, HepG2 and 786-O cell lines were used to carry out in vitro experiments of hepatotoxicity and nephrotoxicity, respectively. The unspecific hairpin did not cause toxicity in cell survival assays (MTT) and produced minor changes in gene expression for selected genes in RT-qPCR arrays specifically developed for hepatic and renal toxicity screening.

Survivin and XIAP expression in distinct tumor compartments of surgically resected gastric cancer: XIAP as a prognostic marker in diffuse and mixed type adenocarcinomas

There is considerable evidence that the inhibitor of apoptosis protein (IAP) family serves a role in tumorigenesis. The most studied IAP family members, survivin and X-linked inhibitor of apoptosis (XIAP), have been demonstrated to serve as biomarkers in distinct tumor entities. Thus, the present study aimed to investigate the expression levels of both IAPs in the tumor center, invasion front and lymph node metastases of surgically resected gastric cancer (GC) specimens. Tissue microarrays containing samples from 201 primary GCs were analyzed. IAP expression was detected using immunohistochemistry in different tumor compartments, normal mucosa and lymph node metastases. In addition, the association between the expression levels of these proteins, and clinicopathological parameters and overall survival was investigated. High levels of survivin and XIAP were evident in GC, when compared with normal mucosa, and were correlated with intestinal-type and well-differentiated GC, as well as low International Union Against Cancer stages. Increased XIAP expression was detected in lymph node metastases as compared with corresponding primary tumors. XIAP overexpression was identified to be an independent negative prognostic marker in diffuse and mixed type GC. These results suggest a potential role of survivin and XIAP in the early phase of gastric carcinogenesis. In addition, increased XIAP expression in lymph node metastases supports the observation that IAPs serve an essential role in metastatic tumor disease. Since XIAP expression was identified to be associated with poor survival in diffuse and mixed type GC, XIAP may serve as a novel therapeutic target in these types of GC.

Role of survivin as prognostic and clinicopathological marker in gastric cancer: a meta-analysis

Survivin has been implicated as a potential prognostic marker in a wide range of malignant tumours. However, the prognostic impact of survivin in gastric cancer remains to be controversial and published data are sometimes heterogeneous. Thus, aim of this study was to review the literature by performing an electronical database search via PubMed and EMBASE to identify eligible studies that assessed the impact of survivin as prognostic marker and its association with clinicopathological variables. Database search until November 21st 2012 retrieved 20 studies comprising 2,695 gastric cancer patients that assessed expression of survivin by immunohistochemistry or RT-PCR analyses in gastric cancer specimens. Meta-analyses of clinicopathological variables revealed an association between the expression of survivin and the presence of lymph node metastases (pooled OR: 0.58; 95 % CI 0.35-0.96). In addition, a correlation between the expression of survivin and overall survival for patients with gastric cancer (pooled HR 1.93; 95 % CI 1.51-2.48) became evident. More importantly, we were able to exclude a severe heterogeneity (I(2) = 31 %) or publication bias for the survival analyses. Furthermore, one-way sensitivity analysis and subgroup analyses regarding the method used to detect survivin, the type of survival analysis, the study quality and whether information was provided regarding neoadjuvant therapy supported our initial results. In conclusion, this meta-analysis indicates the prognostic significance of survivin in patients with gastric cancer.

DcR3 and survivin are highly expressed in colorectal carcinoma and closely correlated to its clinicopathologic parameters

OBJECTIVE

To investigate the expression of death decoy receptor 3 (DcR3) and survivin in colorectal carcinoma.

METHODS

Tumor and normal tissues were taken from a total of 100 colorectal carcinoma patients during surgery, and the expression of DcR3 and survivin was examined by immunohistochemistry, Western blotting, and reverse transcription-polymerase chain reaction (RT-PCR) analyses.

RESULTS

RT-PCR showed that the expression levels of DcR3 mRNA (0.846+/-0.242, P<0.01) and survivin mRNA (0.7835+/-0.2392, P<0.01) in colorectal cancer tissues were significantly higher than those in adjacent normal tissues. Western blotting showed that the expression levels of DcR3 protein (0.795+/-0.261, P<0.01) and survivin protein (0.6765+/-0.1351, P<0.01) in tumor tissues were significantly higher than those in non-cancer tissues. The immunohistochemical streptavidin-peroxidase (SP) method showed that the positive expression rates of DcR3 and survivin were 67.0% and 58.0% in colorectal cancer tissues, and 18.0% and 3.0% in non-cancerous colorectal tissues (P<0.05), respectively. The positive correlations of DcR3 (P<0.01) and survivin (P<0.01) to the differentiation of colorectal carcinoma cells, lymph node metastasis, and pathological stage were observed. The expression of DcR3 and survivin was found to be positively correlated to clinicopathologic parameters of colorectal carcinoma.

CONCLUSION

The overexpressed DcR3 and survivin in colorectal cancer may contribute to the development of the cancer. The monitoring of these two proteins may be useful for the diagnosis, differentiation, metastasis, and determination of stages of colorectal carcinoma.

The association between the survivin C-31G polymorphism and gastric cancer risk in a Chinese population

INTRODUCTION

The C-31G polymorphism in the survivin promoter could de-repress the cell-cycle-dependent transcription of the human survivin gene, resulting in overexpression of survivin. This survivin mutation has only been studied on cervical carcinoma. However, no study has ever been conducted to evaluate the effect of the polymorphism on other cancers, including gastric cancer.

METHODS

In this hospital-based, case-control study, we investigated the association between the survivin C-31G polymorphism and risk of gastric cancer in a Chinese population using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) protocols.

RESULTS

No statistically significant association was observed between gastric cancer risk and the variant genotype (GG + GC). However, the variant genotype (GG + GC) was either associated with risk of distal gastric cancer (odds ratios=0.50, 95% confidence interval=0.30-0.83) or with risk of well-differentiated tumor (odds ratios=0.46, 95% confidence interval=0.22-0.97).

CONCLUSION

Our results demonstrate that the survivin C-31G polymorphism may be involved in distal gastric carcinogenesis and tumor differentiation in a Chinese population.

Inhibitor of apoptosis proteins and apoptosis

Apoptosis is a physiological cell death process that plays a critical role in development, homeostasis, and immune defense of multicellular animals. Inhibitor of apoptosis proteins (IAPs) constitute a family of proteins that possess between one and three baculovirus IAP repeats. Some of them also have a really interesting new gene finger domain, and can prevent cell death by binding and inhibiting active caspases, but are regulated by IAP antagonists. Some evidence also indicates that IAP can modulate the cell cycle and signal transduction. The three main factors, IAPs, IAP antagonists, and caspases, are involved in regulating the progress of apoptosis in many species. Many studies and assumptions have been focused on the anfractuous interactions between these three main factors to explore their real functional model in order to develop potential anticancer drugs. In this review, we describe the classification, molecular structures, and properties of IAPs and discuss the mechanisms of apoptosis. We also discuss the promising significance of clinical applications of IAPs in the diagnosis and treatment of malignancy.

Survivin expression in early hepatocellular carcinoma and post-treatment with anti-cancer drug under hypoxic culture condition

AIM: To investigate the expression of survivin during the early stages of hepatocellular carcinoma (HCC).

METHODS: Immunohistochemical expression of survivin in liver tumor and non-tumor tissue specimens taken from 17 patients was compared. In addition, to determine the survivin expression in response to anti-cancer drugs in early stage HCC, the survivin expression was determined after the treatment of the HCC cells with anti-cancer drugs under hypoxic culture conditions.

RESULTS: Survivin proteins were expressed in 64.7% of cells in early HCC specimens. A correlation between the survivin expression rate in the peritumoral hepatocytes and the rate of expression in the HCC specimens (low-rate group vs high-rate group) was observed. The survivin protein concentration in HCC cells was increased by the combination of hypoxia and anti-cancer drugs.

CONCLUSION: This study suggests that survivin could be used as a therapeutic target in early HCC.

Downregulation of survivin by RNAi inhibits growth of human gastric carcinoma cells

AIM: To investigate the inhibitory effect of a specific small survivin interfering RNA (siRNA) on cell proliferation and the expression of survivin in human gastric carcinoma cell line SGC-7901.

METHODS: To knockdown survivin expression, a small interfering RNA targeting against survivin was synthesized and transfected into SGC-7901 cells with lipofectamine^TM2000. The downregulation of survivin expression at both mRNA and protein levels were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Cell proliferation inhibition rates were determined by methyl thiazolyl tetrazolium (MTT) assay. The effect of survivin siRNA on cell cycle distribution and cell apoptosis was determined by flow cytometry (FCM).

RESULTS: RNA interference could efficiently suppress the survivin expression in SGC-7901 cells. At 48 h after transfection, the expression inhibition rate was 44.52% at mRNA level detected by RT-PCR and 40.17% at protein level by Western blot analysis. Downregulation of survivin resulted in significant inhibition of tumor cell growth in vitro. The cell proliferation inhibition rates at 24, 48 and 72 h after survivin siRNA and non-siliencing siRNA transfection, were 34.06%, 47.61% and 40.36%, respectively. The apoptosis rate was 3.56% and the number of cells was increased in G₀/G₁ phase from 38.2% to 88.6%, and decreased in S and G₂/M phase at 48 h after transfection.

CONCLUSION: Downregulation of survivin results in significant inhibition of tumor growth in vitro. The inhibition of survivin expression can induce apoptosis of SGC-7901 cells. The use of survivin siRNA deserves further investigation as a novel approach to cancer therapy.

Therapeutic effects of survivin antisense oligonucleotide on nude mice bearing human pancreatic carcinoma xenograft

AIM: To investigate the therapeutic effects of survivin antisense oligonucleotide (ASODN) on nude mice bearing human pancreatic carcinoma xenograft.

METHODS: The nude mouse model of pancreatic cancer was established using human pancreatic cancer cell line BxPC-3. The mice bearing tumor were intratumorally injected with survivin ASODN (40 g/200 L per mouse). The tumor size and volume were measured before and after injection. The pathological changes of tumor tissues were observed. The expression level of survivin mRNA was measured by reverse transcription-polymerase chain reaction (RT- PCR), and the activity of caspase-3 was evaluated using a caspase-3 assay kit. The expression of proliferating cell nuclear antigen (PCNA) and microvessel density (MVD) were detected by immunohistochemistry.

RESULTS: Twenty days after injection, the tumor volume and weight were significantly decreased in survivin ASODN group as compared with those in the control and SODN group (427.34 ± 12.44 mm³vs 703.56 ± 12.51, 687.59 ± 12.44 mm³, P < 0.01; 0.57 ± 0.06 g vs 1.16 ± 0.12, 1.07 ± 0.10 g, P < 0.01), and the tumor inhibition rate was 50.86%. The expression of survivin mRNA was decreased by 50%, while the caspase-3 activity was significantly higher in survivin ASODN group than that in the control and SODN group (0.040 ± 0.018 vs 0.006 ± 0.001, 0.007 ± 0.002, P < 0.01). The expression of PCNA and MVD were significantly lower in survivin ASODN group than those in the control and SODN group (28.33 ± 2.16 vs 35.17 ± 3.71, 34.33 ± 3.27, P < 0.01; 15.50 ± 3.08 vs 21.33 ± 2.94, 20.67 ± 2.16, P < 0.01). However, both expression of PCNA and MVD had no significant difference between the control and SODN group (P > 0.05).

CONCLUSION: Survivin ASODN can inhibit the growth of human pancreatic carcinoma xenograft in nude mouse through activating caspase-3 to induce apoptosis, and suppressing the proliferation of pancreatic cancer cells as well as the angiogenesis of carcinoma.

Effects of survivin siRNA expression plasmid on proliferation of MGC-803 cells

AIM: To silence the expression of survivin gene in MGC-803 cells by the siRNA expression vector-based RNA interference (RNAi) technique, and to investigate its effects on the proliferation of MGC-803 cells.

METHODS: The survivin siRNA expression plasmid was transfected into MGC-803 cells by lipofectamine. Morphological changes of the cells were observed under invert microscope. The expression of survivin mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). The changes of cell cycle and the cell proliferation were analyzed by flow cytometry and MTT assay, respectively.

RESULTS: Abnormal morphological changes of MGC-803 cells were observed in the group transfected with the survivin siRNA expression plasmid. The survivin siRNA expression plasmid significantly down-regulated the expression of survivin mRNA in MGC-803 cells with a percentage of 48.2% ( vs empty controls), and it arrested the cell cycle in G1 phase (77.4%). The cell proliferation was significantly inhibited, and the optical density in siRNA-transfected cells was markedly lower than that in the empty controls (24 h: 0.272 ± 0.048 vs 0.576 ± 0.018; 48 h: 0.270 ± 0.060 vs 0.809 ± 0.027; 72 h: 0.143 ± 0.046 vs 1.015 ± 0.075; all P < 0.01). The growth inhibitory rates of MGC-803 cells were 53.4%, 66.7%, and 86.3% after 24, 48, and 72 h of the transfection, respectively.

CONCLUSION: The expression of survivin in MGC-803 cells can be down-regulated by the plasmid-based RNAi technique, and the down-regulation can inhibit the cell proliferation in vitro.

Knockdown of survivin gene expression by RNAi induces apoptosis in human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the survivin gene expression in human hepatocellular carcinoma cell line SMMC-7721 and the effects of survivin gene RNA interference (RNAi) on cell apoptosis and biological behaviors of SMMC-7721 cells.

METHODS: Eukaryotic expression vector of survivin gene RNAi and recombinant plasmid pSuppressorNeo-survivin(pSuNeo-SVV), were constructed by ligating into the vector, pSupperssorNeo (pSuNeo) digested with restriction enzymes Xba I and Sal I and the designed double-chain RNAi primers. A cell model of SMMC-7721 after treatment with RNAi was prepared by transfecting SMMC-7721 cells with the lipofectin transfection method. Strept-avidin- biotin-complex (SABC) immunohistochemical staining and RT-PCR were used to detect survivin gene expressions in SMMC-7721 cells. Flow cytometry was used for the cell cycle analysis. Transmission electron microscopy was performed to determine whether RNAi induced cell apoptosis, and the method of measuring the cell growth curve was utilized to study the growth of SMMC-7721 cells before and after treatment with RNAi.

RESULTS: The eukaryotic expression vector of survivin gene RNAi and pSuNeo-SVV, were constructed successfully. The expression level of survivin gene in SMMC-7721 cells was observed. After the treatment of RNAi, the expression of survivin gene in SMMC-7721 cells was almost absent, apoptosis index was increased by 15.6%, and the number of cells was decreased in G2/M phase and the cell growth was inhibited.

CONCLUSION: RNAi can exert a knockdown of survivin gene expression in SMMC-7721 cells, and induce apoptosis and inhibit the growth of carcinoma cells.

Survivin antisense compound inhibits proliferation and promotes apoptosis in liver cancer cells

AIM: To evaluate the effects of survivin on cell proliferation and apoptosis in liver cancer.

METHODS: MTT assay was used to generate and optimize phosphorothioate antisense oligonucleotides (ODNs)-Lipofectamine^TM2000 (LiP) compound by varying ODNs (μg):LiP (μL) ratios from 1:0.5 to 1:5. Then, liver cancer cells (HepG₂) were transfected with the compound. By using RT-PCR and Western blot, the expression levels of survivin mRNA and proteins were detected in HepG₂ cells treated with antisense compounds (ODNs:LiP = 1:4), and compared with those treated with sense compounds (1:4) as control. MTT assay was applied to the determination of cell proliferation in HepG₂ cells. Active caspase-3 was evaluated by flow cytometric analysis. The morphological changes were assessed by electron microscopy. Laser scanning confocal microscopy was performed to detect the subcellular localization of survivin proteins in treated and untreated cells.

RESULTS: Antisense compounds (1:4) down-regulated survivin expression (mRNA and protein) in a dose-dependent manner with an IC₅₀ of 250 nmol/L. Its maximum effect was achieved at a concentration of 500 nmol/L, at which mRNA and protein levels were down-regulated by 80%. The similar results were found in MTT assay. Antisense compound (1:4)-treated cells revealed increased caspase-3-like protease activity compared with untreated cells. Untreated cells as control were primarily negative for the presence of active-caspase-3. As shown by transmission electron microscopy, treated cells with antisense compounds (1:4) resulted in morphological changes such as blebbing and loss of microvilli, vacuolization in the cytoplasm, condensation of the cytoplasm and nuclei, and fragmented chromatin. Immunofluorescence analysis confirmed the presence of survivin protein pool inside the cytoplasm in untreated cells. Labeled-FITC immunofluorescence staining of survivin clearly showed that survivin was distributed mainly in a spotted form inside the cytoplasm. Whereas cells treated with antisense compounds were rare and weak inside the cytoplasm.

CONCLUSION: Down-regulation of survivin expression induced by the antisense compounds reduces tumor growth potential, promotes apoptosis and affects the localization of survivin proteins in HepG₂ cells. Furthermore, survivin protein is a key molecule associated with proliferation and apoptosis, and antisense oligonucleotides targeting survivin have a bright prospect in the therapy of liver cancer.

Inhibitory effect of antisense oligonucleotide on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the inhibitory effect of survivin antisense oligonucleotide (ASODN) on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721.

METHODS: The 20mer antisense oligonucleotide (ASODN) targeted to the promotor region of survivin mRNA was designed and synthesized. The expression of survivin gene in hepatocellular carcinoma cell line SMMC-7721 was blocked by means of ASODN transfection mediated by DOTAP liposomal reagent. The changes of survivin protein and mRNA expression after transfection were assessd by Western blot and in situ hybridization, respectively. The apoptotic rate was detected by flow cytometer. The changes of cell adherent rate, cell growth activity, and the inhibitory rate of cell growth were also studied.

RESULTS: The expression of survivin protein and mRNA was decreased markedly after survivin ASODN transfection (69.59 vs 10.71, and 75.61 vs 22.94, P < 0.01). Meanwhile, the cell adherent rate also decreased markedly (90.68% vs 33.16%, P < 0.01) while the apoptotic rate increased markedly (0.7% vs 31.35%, P < 0.01). The inhibitory effect on the cell growth could maintain about a week after transfection, and the highest inhibitory rate could be 71.8% three d after transfection.

CONCLUSION: Transfection of ASODN targeted to the promotor region of survivin mRNA by DOTAP liposomal transfection reagent can down-regulate the expression of survivin protein and mRNA significantly in 7721 cell line and inhibit the proliferation of cancer cells. survivin may be an important target in the therapy of hepatocellular carcinoma.

Effects of BAK gene over-expression on apoptosis in gastric cancer cells and its molecular mechanisms

AIM: To explore the apoptosis-inducing effects of extrinsic BAK gene transfer and its over-expression on gastric cancer cells and its molecular mechanisms.

METHODS: The eukaryotic expression for BAK gene was constructed and transferred into gastric cancer MKN-45 cell line. After being transferred for 1 to 5 d, cellular BAK gene expression was detected by RT-PCR and Western blotting methods. The growth activities of cancer cells were detected by cell count and MTT colorimetry. Cell cycle changes were assayed by flow cytometry. Cellular apoptosis was assayed by electronic microscopy and in situ terminally labeled transferase technique (TUNEL). Cellular caspase-3 activities were observed by colorimetric method.

RESULTS: After being transferred for 1 to 5 d, cellular BAK mRNA and protein expression levels were significantly increased (P < 0.01). In vitro growth of gastric cancer cells was inhibited by 11.6-35.3% (P < 0.01). The cellular proliferation activities were decreased by 10.2-32.4% (P < 0.01), with cell cycle being blocked at G0/G1 phase. Partial cancer cells presented the characteristic morphological changes of apoptosis, with the apoptotic rates being 21.4% (P < 0.01). The cellular caspase-3 activities were enhanced by 4.45 times (P < 0.01).

CONCLUSION: Transfection of extrinsic BAK gene, resulting in its over-expression, can significantly induce apoptosis of gastric cancer MKN-45 cells through activating caspase-3, which is a potential strategy for gene therapy of gastric cancer.

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.