EFFECTS OF MUTATION AND EXPRESSION OF PTEN GENEmRNA ON TUMORIGENESIS AND PROGRESSION OFEPITHELIAL OVARIAN CANCER

Objective To investigate the mutation and expression of tumor suppressor gene-PTEN mRNA and explore their roles in tumorigenesis and progression of ovarian cancer. Methods Mutated exon 5 of PTEN gene was examined in normal ovary(n = 5), ovarian cyst (n =5), ovarian borderline tumor (n = 9), epithelial ovarian cancer(n = 60), and ovarian cancer cell line (n = 1)by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). mRNA expression of PTEN gene was evaluated in corresponding tissues and cell line by reverse transcription polymerase chain reaction(RT-PCR). The mutation and mRNA expression of PTEN gene were compared with clini-copathological features of ovarian cancer. Results Mutated exon 5 of PTEN gene was detected only in 5(7.1%)cases of epithelial ovarian cancer. mRNA expression level of PTEN gene in ovarian borderline tumor or ovarian cancer was lower than that in normal ovary or ovarian cyst(P < 0.05). The level of PTEN gene mRNA expression was negatively correlated with clinicopathological staging of ovarian cancer, whereas positively correlated with histological differentiation (P < 0.05). mRNA expression level of PTEN gene in ovarian endometrioid cancer was significantly lower than that in ovarian serous or mucinous cancer (P < 0.05=. Conclusions Mutation of PTEN gene occurs in ovarian cancer. Down-regulated expression of PTEN is probably an important molecular event in tumorigenesis of ovarian cancer. Abnormal expression of PTEN gene is involved in progression of ovarian cancer. Reduced expression of PTEN gene is closely associated with tumorigenesis and pathobiological behaviors of ovarian endometrioid cancer.

Expression of vascular endothelial growth factor and its role in oncogenesis of human gastric carcinoma

AIM: To establish the role of vascular endothelial growth factor (VEGF) in the oncogenesis of human gastric carcinoma more directly. METHODS: The expression of VEGF and its receptor kinase-domain insert containing receptor (KDR) in human gastric cancer tissue were observed by immunohistochemical staining. VEGF levels were manipulated in human gastric cancer cell using eukaryotic expression constructs designed to express the complete VEGF(165) complimentary DNA in either the sense or antisense orientation. The biological changes of the cells were observed in which VEGF was up-regulated or down-regulated. RESULTS: VEGF-positive rate was 50%, and VEGF was mainly localized in the cytoplasm and membrane of the tumor cells, while KDR was mainly located in the membrane of vascular endothelial cells in gastric cancer tissues and peri-cancerous tissue. In 2 cases of 50 specimens, the gastric cancer cells expressed KDR, localized in both the cytoplasm and membrane. Introduction of VEGF(165) antisense into human gastric cancer cells (SGC-7901, immunofluorescence intensity, 31.6%)) resulted in a significant reduction in VEGF-specific messenger RNA and total and cell surface VEGF protein (immunofluorescence intensity, 8.9%) (P【0.05). Conversely, stable integration of VEGF(165) in the sense orientation resulted in an increase in cellular and cell surface VEGF (immunofluorescence intensity, 75.4%) (P【0.05). Lowered VEGF levels were associated with a marked decrease in the growth of nude mouse xenografted tumor (at 33 days postimplantation, tumor volume: 345.40 +/- 136.31 mm3)(P【0.05 vs control SGC-7901 group: 1534.40 +/- 362.88 mm3), whereas up-regulation of VEGF resulted in increased xenografted tumor size (at 33 days postimplantation, tumor volume: 2350.50 +/- 637.70 mm3) (P【0.05 vs control SGC-7901 group). CONCLUSION: This study provides direct evidence that VEGF plays an important role in the oncogenesis of human gastric cancer.

The clinical significance of the expression of the metastasis suppressor gene KAI1 in epithelial ovarian carcinoma

Objective:To investigate the potential role of KAI1 in epithelial ovarian carcinoma(EOC), and to determine whether the expression of the KAI1 gene is associated with EOC progression.The clinical significance in this tumor is also evaluated.Method: Immunohistochemistry SP method was performed to examine the expression level of KAI1 in EOC.Results: Thirty eight of 66 cancer specimens showed KAI1 protein positive (57.58%),which lower significantly than that in the patients with benign and borderline tumors(90.91%).The statistical evaluation showed that the expression of KAI1 had a correlation with FIGO stags as well as lymph node metastasis(or distant metastasis)(P<0.05).It also revealed an inverse relationship between histological grade and KAI1 expression (P<0.05).Conclusion: KAI1 protein expression is closely correlated with the malignent progression and metastasis of EOC; detecting the expression of KAI1 probably possesses clinical significance in evaluating the differentiation,tumor progression and predicting the prognosis of EOC.

Study of cellular immunity response of mB7-1 gene transfected mouse ovarian cancer cell line and its tumorigenecities in vivo

Objective:To investigate the cellular immunity response in vitro and the tumorigenecities in vivo of mB7 1 gene transfected murine ovarian cancer cell line.Methods:mB7 1 gene was transfected into the NuTu 19 cell line by retrovirus vector, and the expression of mB7 1 gene was confirmed by flow cytometry(FCM).NuTu 19/neo and NuTu 19/mB7 1 cells were injected subcutaneously into syngeneic Fischer 344 rats respectively,and their tumorigenecities were recorded.Proliferation indices of lymphocyte were assayed after syngenieic mixed tumor lymphocyte cultures(MTLCs).The lysis activity of CTL toward tumor cells was determined using methyl thiazolyl tetrazolium(MTT) assay.Results:Successful transfection of mB7 1 gene into NuTu 19 cell line was comfirmed with FCM.In vitro study showed that there was no obvious changes in cell growth of gene transfected cell line,compared with the cell line NuTu 19.NuTu 19/mB7 1 cells could induce more effective proliferation of effector lymphocytes(P<0.05). The lysis activity of CTL activated by NuTu 19/mB7 1 was stronger than that of NuTu 19/neo (P<0.01).Tumor sizes were smaller in the NuTu 19/mB7 1 receptance syngeneic Fischer 344 rats compared with those in the control group.Conclusion:mB7 1 genetically modified ovarian cancer cells could induce the cellular immunity response in vitro and the tumorigenecitiy of NuTu 19 cells was decreased after inoculation with the experimental vaccine.

Expression Profile of Immune-Associated Genes in the Kidney of Cultured Large Yellow Croaker Larimichthys crocea in the East China Sea Area

To explore the effect of environment conditions on immune activity of fish, eight immune-associated genes responsible for innate immunity were selected from the Gen Bank, i.e. Pgrn-a, Ifit2, P-hepcidin, Lect2, β2m, Irf1, Il25 and Hsp96, and the m RNA expressions of them in the kidney of cultured large yellow croaker Larimichthys crocea in different sea areas in the East China Sea were examined with q PCR techniques. In the contrasts of immune-associated gene expression between areas and populations, significant differences were found, expression levels of these immune-associated genes were lower in the clear water area than in the poor water quantity area, and lower in May than in October. MY was more sensitive to environmental factors than DQ, which was coincident with the water quality in the culturing areas. Differential analyses of the expression levels of these immune-associated genes showed that significant up-regulation could be triggered by poor environmental factors. The expression patterns indicated that the expression levels of these genes were sensitive to ecological changes, thereby the immune-associated genes, especially Pgrn-a, Ifit2, β2m, Il25 and Hsp96, might serve as immediate and sensitive indicators of population immunologic vigor and ecosystem health. But the expression of immunity-associated genes at the level of gene transcription is highly influenced by multiple factors, and the exact causes or influencing factors of the up-regulation or down-regulation of these genes still need further thorough investigation.

Identification of differentially expressed genes in normal mucosa,adenoma and adenocarcinoma of colon by SSH

AIM: To construct subtracted cDNA libraries and further identify differentially expressed genes that are related to the development of colorectal carcinoma(CRC). METHODS: Suppression subtractive hybridization(SSH) was done on cDNAs of normal mucosa, adenoma and adenocarcinoma tissues from the same patient. Three subtracted cDNA libraries were constructed and then hybridized with forward and backward subtracted probes for differential screening. Positive clones from each subtracted cDNA library were selected for sequencing and BLAST analysis. Finally, virtual Northern Blot confirmed such differential expression. RESULTS: By this way, there were about 3-4 X 10(2) clones identified in each subtracted cDNA library, in which about 85% positive clones were differentially screened. Sequencing and BLAST homology search revealed some clones containing sequences of known gene fragments and several possibly novel genes showing few or no sequence homologies with any known sequences in the database. CONCLUSION: All results confirmed the effectiveness and sensitivity of SSH. The differentially expressed genes during the development of CRC can be used to shed light on the pathogenesis of CRC and be useful genetic markers for early diagnosis and therapy.

Applying a highly specific and reproducible cDNA RDA method to clone garlic up-regulated genes in human gastric cancer cells

AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.

Differential expression of a novel colorectal cancer differentiation-related gene in colorectal cancer

AIM: To investigate SBA2 expression in CRC cell lines and surgical specimens of CRC and autologous healthy mucosa. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used for relative quantification of SBA2 mRNA levels in 4 human CRC cell lines with different grades of differentiation and 30 clinical samples. Normalization of the results was achieved by simultaneous amplification of beta-actin as an internal control. RESULTS: In the exponential range of amplification, fairly good linearity demonstrated identical amplification efficiency for SBA2 and beta-actin (82%). Markedly lower levels of SBA2 mRNA were detectable in tumors, as compared with the coupled normal counterparts P【0.01). SBA2 expression was significantly (0.01】P 【 0.05) correlated with the grade of differentiation in CRC, with relatively higher levels in well-differentiated samples and lower in poorly-differentiated cases. Of the 9 cases with lymph nodes affected, 78% (7/9) had reduced SBA2 mRNA expression in contrast to 24% (5/21) in non-metastasis samples 0.01】P【0.05). CONCLUSION: SBA2 gene might be a promising novel biomarker of cell differentiation in colorectal cancer and its biological features need further studies.

Cloning of differentially expressed genes in human hepatocellular carcinoma and nontumor liver

INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in gene expression which distinguished tumor from nontumor[1-6].The new genes,especially the functional genes directly related with tumor are still worth being found.The purpose of our study is to find the different genes between human liver tumor and normal tissues using suppression subtractive hybridization.

Cloning of WWOX Gene and Its Growth-inhibiting Effects on Ovarian Cancer Cells

The growth-inhibiting and apoptosis-inducing effects of WW domain-containing oxidoreductase(WWOX) gene on ovarian cancer cell line A2780 were investigated.The full length cDNA of human WWOX gene was amplified from normal human ovary tissues.The correct cDNA of full length WWOX was subcloned into eukaryocytic expression vector pCMV.After introduction of WWOX gene into cancer cells with liposome,the WWOX mRNA and protein level in the cancer cells were detected by reverse transcription polymerase chain reaction(RT-PCR) and immunoblotting.The growth activities of cancer cells were detected by Trypan blue staining.The clone formation assay in soft agar was employed to observe the proliferation of the cancer cells.Apoptosis was examined by DNA ladder and acridine orange-ethidium bromide fluorescent staining.The results showed that 72 h after WWOX gene transfection,the WWOX expression was increased significantly(P<0.01).The growth of ovarian cancer cells was decreased by 16.41% to 38.49%(P<0.01).The clone formation abilities were reduced(P<0.01).Some cancer cells presented the characteristic morphological changes of apoptosis with obvious ladder bands on electrophoresis.The apoptosis rate was(20.7±6.0)%(P<0.01).It was concluded that over-expression of WWOX gene could induce apoptosis and inhibit the growth of ovarian cancer cells,which might be potentially useful in the gene therapy of ovarian cancers.

Identification of differentially expressed genes in human uterine leiomyomas using differential display

In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were eliminated by reverse Northern analysis. Positives were confirmed by Northern blot analysis. RESULTS: Four of 69 cDNA fragments (3 up-regulated named L1, L2 and L3 and 1 down-regulated named M1 in leiomyoma) were confirmed by Northern analysis. Sequence comparison and Northern analysis proved that L1 is exactly the human ribosomal protein S19. It was present ubiquitously in 13 tissues tested but in various levels and even in different size. L1 was highly expressed in parotidean cystadenocarcinoma, pancreatic cancer and breast cancer examined. No mutations have been found in human uterine leiomyomas (n=6). CONCLUSIONS: hRPS19 overexpression might be a universal signal in rapid cell growth tissues.

Alterations in metastatic properties of hepatocellular carcinoma cell following H-ras oncogene transfection

AIM: To demonstrate the relationship between H-ras oncogene and hepatocellular carcinoma (HCC) metastasis. METHODS: Activated H-ras oncogene was transfected into SMMC 7721, a cell line derived from human HCC, by calcium phosphate transfection method. Some metastasis-related parameters were detected in vitro, including adhesion assay, migration assay, expression of collagenase IV(c IV ase) and epidermal growth factor receptor (EGFR). RESULTS: The abilities of H-ras-transfected cell clones in adhesion to laminin (LN) or fibronectin (FN), migration, c IV ase secretion increased markedly, and the expression of EGFR elevated moderately. More importantly, these alterations were consistent positively with the expression of p21, the protein product of H-ras oncogene. CONCLUSION: H-ras oncogene could induce the metastatic phenotype of HCC cell in vitro to raise its metastatic potential.

Methylation status of c-fms oncogene in HCC and its relationship with clinical pathology

INTRODUCTIONThe mechanism that DNA hypomethylation leads toactivation of oncogene and occurrence of malignantneoplasm is being increasingly recognized byresearchers. Normal DNA methylation playsimportant role in stabilizing the phenotype of cell.DNA methylation status reduction and/or patternalteration are related to activation and abnormallyhigh expression of some oncogenes and cellularmalignancy[1-6]. c-fms oncogene encodes for colonystimulating factor 1 receptor (CSF-1R)[7], c-fms/CSF-1R was highly expressed in hepatocellularcarcinoma (HCC) tissue, but the mechanismremained obscure[8,9].

Effect of 5-Aza-2'-deoxycytidine on the P16 tumor suppressor gene in hepatocellular carcinoma cell line HepG2

INTRODUCTIONHepatocellular carcinoma (HCC) is one of the mostcommon human malignancies worldwide[1,2], and isclosely associated with infection of HBV and HCVand contamination of aflatoxin B1[3-6]. Althoughthe molecular mechanisms of hepatocarcinogenesisremain poorly understood, an increasing number ofgenetic abnormalities have been recognized[7-10],for example, the p16 gene[11,12] the p53gene[13-18], the E-cadherin gene[19], and the c-mycgene[20].

Relationship between Fas/ FasL expression and apoptosis of colon adenocarcinoma cell lines

INTRODUCTIONFas/ FasL system has been identified as a keymediator of apoptosis in tumor cells[1-4]. Theoccurrence and development of neoplasm are closelyrelated to apoptosis[5-7] Most chemotherapeuticdrugs kill cancer cells mainly by inducingapoptosis[8-14].'

Transplantation of human hepatocytes into tolerized genetically immunocompetent rats

AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.

Altered expression of nuclear matrix proteins in etoposide induced apoptosis in HL-60 cells

The events of cell death and the expression of nuclear matrix protein (NMP) have been investigated in a promyelocytic leukemic cell line HL-60 induced with etoposide. By means of TUNEL assay, the nuclei displayed a characteristic morphology change, and the amount of apoptotic cells increased early and reached maximun about 39% after treatment with etoposide for 2 h. Nucleosomal DNA fragmentation was observed after treatment for 4 h. The morphological change of HL-60 cells, thus, occurred earlier than the appearance of DNA ladder. Total nuclear matrix proteins were analyzed by 2-dimensional gel electrophoresis. Differential expression of 59 nuclear matrix proteins was found in 4 h etoposide treated cells. Western blotting was then performed on three nuclear matrix acssociated proteins, PML, HSC70 and NuMA. The expression of the suppressor PML protein and heat shock protein HSC70 were significantly upregulated after etoposide treatment, while NuMA, a nuclear mitotic apparatus protein, was down regulated. These results demonstrate that significant biochemical alterations in nuclear matrix proteins take place during the apoptotic process.

黄芪多糖对乳腺癌细胞抑制作用机制研究

目的 考察黄芪多糖对乳腺癌细胞的抑制作用并预测参与的通路,对关键通路进行验证,并对涉及的免疫通路进行富集分析。方法 采用CCK-8法检测不同浓度黄芪多糖(0、0.5、1.0、2.0、4.0、8.0 mg/mL)对乳腺癌MDA-MB-231细胞增殖的抑制作用;对黄芪多糖给药组和对照组进行基因表达谱测定,筛选差异表达基因,应用R语言clusterProfiler包将筛选出的差异表达基因进行京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)分析。采用Western blot法检测黄芪多糖处理后乳腺癌MDA-MB-231细胞Wnt信号通路Wnt1和β-catenin蛋白的表达;应用ImmPort数据库免疫相关基因集与差异表达基因取交集,进行免疫相关通路分析;考察不同组别程序性细胞死亡配体1(programmed cell death ligand 1,PD-L1)的表达水平。结果 黄芪多糖以浓度依赖性方式抑制乳腺癌细胞增殖作用,与对照组相比,黄芪多糖给药组共筛选出363个差异表达基因,主要富集在Wnt信号通路、ECM受体相互作用、乳腺癌等;Western blot分析进一步证实黄芪多糖能够浓度依赖性抑制Wnt信号通路中Wnt1和β-catenin蛋白的表达。与ImmPort数据库免疫基因集进行交集后获取到42个差异表达的免疫基因,KEGG通路富集结果提示,通路主要富集在抗原提呈、炎症反应和TNF信号通路,提示黄芪多糖可能主要通过增加抗原提呈作用介导其发挥乳腺癌免疫调节作用。黄芪多糖能适度降低PD-L1的表达水平,但差异无统计学意义。结论 黄芪多糖以浓度依赖性方式抑制乳腺癌细胞增殖,主要通过Wnt信号通路发挥其抑制作用,此外免疫调节方面可能通过增加抗原提呈作用介导乳腺癌免疫调节作用。

盐酸双吗啡肽对耐药食管癌细胞迁移和侵袭能力的影响

目的 探讨骨形态发生蛋白(BMP)小分子抑制剂盐酸双吗啡肽(Dorsomorphin)对耐药食管癌EC109/PTX细胞迁移和侵袭能力的影响。方法 MTT实验检测不同浓度盐酸双吗啡肽对EC109/PTX细胞增殖的影响并确定后续实验的浓度。以筛选出的1μmol/L盐酸双吗啡肽的浓度作为试验组,同时设立空白对照组,处理EC109/PTX细胞48 h。采用流式细胞仪检测盐酸双吗啡肽对EC109/PTX细胞凋亡的影响。采用划痕实验和Transwell实验检测两组EC109/PTX细胞的迁移和侵袭能力。采用Western blotting实验检测两组EC109/PTX细胞中Vimentin、E-cadherin、N-cadherin蛋白相对表达水平。结果 1μmol/L盐酸双吗啡肽对EC109/PTX细胞的细胞抑制率为(9.89±1.12)%。培养第48小时时,对照组和实验组EC109/PTX细胞的凋亡率比较差异无显著性(P>0.05)。划痕实验和Transwell实验显示,与对照组相比,实验组EC109/PTX细胞的迁移率和细胞穿膜率显著降低(t=85.42、19.65,P<0.05)。Western blotting实验显示,与对照组相比,实验组细胞中Vimentin、N-cadherin蛋白相对表达量显著降低(t=19.40、41.79,P<0.05),N-cadherin蛋白表达量显著增高(t=58.12,P<0.05)。结论 BMP抑制剂盐酸双吗啡肽能影响耐药食管癌细胞中EMT相关蛋白表达,从而抑制耐药肿瘤细胞的迁移和侵袭。

Expression of cyclin genes in human gastric cancer and in first degree relatives

OBJECTIVE: To clarify the role of these cyclins in human gastric cancer. METHODS: 38 gastric cancer patients, 29 first degree relatives of gastric cancer patients, as well as 18 healthy subjects were included. The mRNA expression of cyclins D1, D2, D3 and E in gastric biopsies was evaluated by RT-PCR analysis using specific primers. Histomorphological features such as intestinal metaplasia, atrophy, H. pylori infection and severity of gastritis were determined by the updated Sydney System. RESULTS: Significant mRNA overexpression was found for cyclins D2, D3 and E compared with healthy normal specimen, but cyclin D1 expression was not different between tumor and normal tissues. In addition, cyclin D2 and D3 overexpression was significantly more frequent in first degree relatives than in healthy controls (P