Biomedical subjects

Yan Xin

Publications and source records attributed to Yan Xin.

At least 19 recordsLinked to original sources

PubMed2006

Enzyme specific activation of benzoquinone ansamycin prodrugs using HuCC49DeltaCH2-beta-galactosidase conjugates.

To activate prodrugs for cancer treatment, an anti-TAG-72 antibody (HuCC49DeltaCH2) was used for delivery of an activation enzyme (beta-galactosidase) to specifically activate a geldanamycin prodrug (17-AG-C2-Gal) against colon cancer. The geldanamycin prodrug 17-AG-C2-Gal was synthesized by coupling a galactose-amine derivative with geldanamycin at the C-17 position. Molecular docking with two different programs (Affinity and Autodock) showed that the prodrug (17-AG-C2-Gal) was unable to bind to Hsp90; however, the product (17-AG-C2), enzymatically cleaved by beta-galactosidase conjugate, bound to Hsp90 in a similar way as geldanamycin and 17-AG. The computational docking results were further confirmed in experimental testing by the tetrazolium [3-(4,5-dimethythiazol-2-yl)]-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and mass spectrometry. HuCC49DeltaCH2 was chemically conjugated to beta-galactosidase. The antibody-enzyme conjugate was able to target tumor antigen TAG-72 with the well-preserved enzymatic activity to activate 17-AG-C2-Gal prodrug. The released active drug 17-AG-C2 was demonstrated to induce up to 70% AKT degradation and enhance anticancer activity by more than 25-fold compared to the prodrug.

Antibodies, Monoclonal↗

PubMed2006

Loss of heterozygosity and microsatellite instabilities of fragile histidine triad gene in gastric carcinoma.

AIM: To detect the loss of heterozygosity (LOH) and microsatellite instabi1ities (MSI) of fragile histidine triad (FHIT) gene in gastric carcinoma and to study their association with the clinical pathological characteristics of gastric carcinoma. METHODS: LOH and MSI of FHIT gene were detected at four microsaterllite loci D3Sl3H, D3S4l03, D3Sl48l and D3S1234 using PCR in matched normal and cancerous tissues from 50 patients with primary gastric cancer. RESULTS: The average frequency of LOH and MSI of FHIT gene in gastric cancer was 32.4% and 26.4% respectively. LOH and MSI of FHIT gene in gastric cancer had no association with histological, Borrmann, and Lauren's classification. LOH of FHIT gene in gastric cancer was related to invasive depth. The frequency of FHIT LOH in gastric cancer with serosa-penetration was obviously higher than that in gastric cancer without serosa-penetration (73.5% vs 37.5%, P < 0.05). MSI of FHIT gene in gastric cancer was associated with the lymph node metastasis. The frequency of MSI in gastric cancer without lymph node metastasis was significantly higher than that in gastric cancer with lymph node metastasis (66.7% vs 34.3%, P < 0.05). CONCLUSION: LOH of FHIT gene is correlated with invasive depth of gastric carcinoma. MSI of FHIT gene is correlated with lymph node metastases. LOH and MSI of FHIT gene play an important role in carcinogenesis of gastric cancer.

Acid Anhydride Hydrolases↗

PubMed2006

[Analysis of genes related to sensitivity to navalbine and docetaxel in 10 lung cancer cell lines].

OBJECTIVE: To analyze the drug-sensitivity-related genes to anti-tumor drugs navalbine (NVB) and docetaxel (Doc) in four SCLC and six NSCLC cell lines. METHODS: The sensitivity of 4 SCLC lines and 6 NSCLC lines to NVB and to Doc was determined with MTT test. The expression of 1291 anti-tumor drug sensitivity-related genes in the 10 cell lines was assayed by cDNA macroarray technique, and cluster analysis was performed to find the relationship between the results obtained by the above mentioned two measurements. RESULTS: (1) The anti-tumor effect of NVB on the 10 cell lines was apparently better than that of Doc. (2) The drug sensitivity-related genes in these 10 cell lines showed a more close positive correlation with Doc than that with NVB, whereas more genes showed negative correlation with NVB than that with Doc. But in 6 NSCLC cell lines, more genes showed the same positive or negative correlation with the two drugs. (3) 51 genes in the 10 cell lines showed correlation with Doc or NVB. 13 of them had negative correlation with Doc, 11 of them showed positive correlation. 24 of them showed negative correlation with NVB, 3 of them showed positive correlation. 67 genes in 6 NSCLC cell lines showed a correlation with sensitivity to Doc or NVB, among them 34 had negative correlation with Doc, 4 had positive correlation. 25 genes had negative correlation with NVB, 4 had positive correlation. (4) Rab 1, Rab 3, Rho B, Rho C, Rac 1, Rac 2, Gho GDI beta, CD44, integrin alpha5, integrin alpha6, integrin beta5, vinculin showed to be cytoskeleton-related genes differently expressing in SCLC or NSCLC cell lines. CONCLUSION: There is obvious difference in the drug sensitivity-related genes to NVB or Doc between SCLC and NSCLC cell lines.

Antineoplastic Agents↗

PubMed2006

[Exogenous PTEN enhances apoptosis in pancreas cancer cell line ASPC-1 induced by hypoxia].

OBJECTIVE: To investigate the effect of exogenous phosphatase and tensin homologue deleted on chromosome ten (PTEN) on cell cycle, the expression of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) proteins, and cellular proliferation ability in human pancreas cancer cell line (ASPC-1) exposed to normal oxygen or hypoxia 1% for 24 h were determined. METHODS: ASPC-1 cells were transfected in vitro with an eukaryotic expression plasmid (pEAK8) containing PTEN or not by lipofectin. Positive cell clones were selected, amplified and named ASPC-1-pEAK8-PTEN or ASPC-1-pEAK8 cells. RT-PCR and Western blot were used to determine the target gene expression. PTEN, VEGF and EGFR proteins were assessed by Western blot assay. Cell cycle and the induction of apoptosis were detected by flow cytometry. The tumor growth ability in vivo was assessed in nude mice, and cologenic survival ability was assayed under normal oxygen or hypoxia condition. RESULTS: The expression of PTEN mRNA and protein in ASPC-1-pEAK8-PTEN cells were significantly higher than that in ASPC-1-pEAK8 or ASPC-1 cells. The expression of VEGF protein in ASPC-1-pEAK8-PTEN cells decreased by 23.4%, but EGFR showed no change. The plating efficiency was decreased by 28.0% (F = 4.283, P < 0.05) under normal oxygen condition, compared with those in ASPC-1 cells. The tumor volume in nude mice with ASPC-1-pEAK8-PTEN were significantly different compared to those with ASPC-1 5 weeks after implantation (t = 4.834, P < 0.01). The tumor inhibitory rate was 42.4% in ASPC-1-pEAK8-PTEN group. The expressions of VEGF and EGFR were decreased by 31.4% and 25.0%, respectively. In comparison with ASPC-1 cells, the plating efficiency of ASPC-1-pEAK8-PTEN cells was decreased by 33.2% (F = 9.152, P < 0.01) under hypoxic condition. The cellular apoptosis 8 h after hypoxia and G(2)/M blockage in ASPC-1-pEAK8-PTEN cells were remarkably higher than those in ASPC-1 cells. CONCLUSION: Exogenous PTEN can block ASPC-1 cell cycle at the G(2)/M phase, enhance the cell apoptosis induced by hypoxia, inhibit the expression of VEGF and EGFR proteins under hypoxic condition, and inhibit the proliferation and growth of ASPC-1 cells.

Animals↗

PubMed2006

[Down-regulation of Caspase-3 expression in precancerous lesions and its relation to gastric carcinogenesis].

OBJECTIVE: To study the level of expression of Caspase-3 protein in precancerous lesions of stomach and its relation to gastric carcinogenesis. METHODS: Formalin-fixed paraffin embedded tissues from 184 cases of gastric mucosa biopsy and surgically removed specimens, including gastric cancer (GC, N = 20), chronic atrophic gastritis (CAG, N = 6), atrophic gastritis with intestinal metaplasia (IM, N = 31), atrophic gastritis with dysplasia (DYS, N = 114) and normal controls (N = 13) were examined for expression of Caspase-3 protein and Ki-67 index by SABC immunohistochemistry, and for apoptosis by TdT-mediated dUTP biotin nick end labeling (TUNEL) method. Caspase-3, Ki-67 and TUNEL index were compared in different stages of gastric precancerous lesions and their correlation was analyzed. RESULTS: The positive index of Caspase-3 protein in severe DYS (29.8% +/- 3.9%) showed no significant difference compared with that in GC (26.9% +/- 3.0%, P > 0.05), but was significantly lower than that in low (58.3% +/- 4.2%) and moderate grade DYS (50.4% +/- 4.8%), CAG (68.3% +/- 3.3%) and IM (70.9% +/- 4.3%, P < 0.05). Caspase-3 positive index was significantly correlated with that of apoptosis detected by TUNEL (r = 0.94, P < 0.05). Ki-67 index in Caspase-3 protein positive group (18.3% +/- 2.2%) was significantly lower than that in Caspase-3 negative group (48.9% +/- 3.1%, P < 0.05). CONCLUSION: Caspase-3 protein expression was upregulated in CAG with or without IM and low or moderately low in DYS, while down-regulated in severe DYS and gastric carcinoma, and significantly positively correlated with cell apoptosis. It is suggested that down-regulated expression of Caspase-3 protein somehow contributes to gastric carcinogenesis through an imbalance between cell apoptosis and proliferation.

Adult↗

PubMed2005

Relationship between abnormality of FHIT gene and EBV infection in gastric cancer.

AIM: To examine the aberrant expression of fragile histidine triad (FHIT) gene and protein in gastric cancer, and to evaluate the role of FHIT gene and the relationship between FHIT gene and EBV infection in gastric carcinogenesis. METHODS: FHIT transcripts were detected by nested RT-PCR in 30 cases of gastric cancer and their products were sequenced. FHIT protein was detected by Western blot. EBV infection was detected by PCR method in 50 cases of gastric cancer. RESULTS: The wild type transcripts were detected in all 30 matched normal tissues of gastric cancer. Aberrant transcripts were found in 11/30 (36.7%) gastric cancerous tissues. Sequencing analysis of the aberrant fragments found an RT-PCR product missing exons 5-7 in one case of gastric cancer, and another product missing exons 4-7. Four of ten (40.0%) cases of primary gastric cancer showed absent or decreased expression of FHIT protein as compared with their matched normal tissues. EBV was detected in 5/50 (10%) gastric cancers, among which 4/5 (80%) had aberrant transcripts of FHIT gene. CONCLUSION: Loss of FHIT gene or FHIT protein p1ays an important role in carcinogenesis, development and progression of gastric cancer. EBV infection might influence carcinogenesis of gastric cancer by inducing the abnormality of FHIT gene.

Acid Anhydride Hydrolases↗

PubMed2005

Loss of heterozygosity on 10q23.3 and mutation of tumor suppressor gene PTEN in gastric cancer and precancerous lesions.

AIM: To investigate the loss of heterozygosity (LOH) and mutation of tumor suppressor gene PTEN in gastric cancer and precancerous lesions. METHODS: Thirty cases of normal gastric mucosa, advanced and early stage gastric cancer, intestinal metaplasia, atrophic gastritis, and atypical hyperplasia were analyzed for PTEN LOH and mutations within the entire coding region of PTEN gene by PCR-SSCP denaturing PAGE gel electrophoresis, and PTEN mutation was detected by PCR-SSCP sequencing followed by silver staining. RESULTS: LOH rate found in respectively atrophic gastritis was 10% (3/30), intestinal metaplasia 10% (3/30), atypical hyperplasia 13.3% (4/30), early stage gastric cancer 20% (6/30), and advanced stage gastric cancer 33.3% (9/30), None of the precancerous lesions and early stage gastric cancer showed PTEN mutations, but 10% (3/30) of the advanced stage gastric cancers, which were all positive for LOH, showed PTEN mutation. CONCLUSION: LOH of PTEN gene appears in precancerous lesions, and PTEN mutations are restricted to advanced gastric cancer, LOH and mutation of PTEN gene are closely related to the infiltration and metastasis of gastric cancer.

Base Sequence↗

PubMed2005

Mutations of mitochondrial 12S rRNA in gastric carcinoma and their significance.

AIM: To detect the variations of mitochondrial 12S rRNA in patients with gastric carcinoma, and to study their significance and the relationship between these variations and the genesis of gastric carcinoma. METHODS: PCR amplified mitochondrial 12S rRNA of 44 samples including 22 from gastric carcinoma tissues and 22 from adjacent normal tissues, was detected by direct DNA sequencing. Then laser capture microdissection technique (LCM) was used to separate the cancerous cells and dysplasia cells with specific mutations. Denaturing high performance liquid chromatography (DHPLC) plus allele-specific PCR (AS-PCR), nest-PCR and polyacrylamide gel electrophoresis (PAGE) were used to further evaluate this mutant property and quantitative difference of mutant type between cancerous and dysplasia cells. Finally, RNAdraw biosoft was used to analyze the RNA secondary structure of mutant-type 12S rRNA. RESULTS: Compared with Mitomap database, some new variations were found, among which np652 G insertion and np716 T-G transversion were found only in cancerous tissues. There was a statistic difference in the frequency of 12S rRNA variation between intestinal type (12/17, 70.59%) and diffusive type (5/17, 29.41%) of gastric carcinoma (P<0.05). DHPLC analysis showed that 12S rRNA np652 G insertion and np716 T-G transversion were heteroplasmic mutations. The frequency of 12S rRNA variation in cancerous cells was higher than that in dysplasia cells (P<0.01). 12S rRNA np652 G insertion showed obviously negative effects on the stability of 12S rRNA secondary structure, while others such as T-G transversion did not. CONCLUSION: The mutations of mitochondrial 12S rRNA may be associated with the occurrence of intestinal-type gastric carcinoma. Most variations exist both in gastric carcinomas and in normal tissues, and they might not be the characteristics of tumors. However, np652 G insertion and np716 T-G transversion may possess some molecular significance in gastric carcinogenesis. During the process from normality to dysplasia, then to carcinoma, 12S rRNA tends to convert from homoplasmy (wild type) to heteroplasmy, then to homoplasmy (mutant type, np717 T-G).

Base Sequence↗

PubMed2005

Quantitative analysis of tumor mitochondrial RNA using microarray.

AIM: To design a novel method to rapidly detect the quantitative alteration of mtRNA in patients with tumors. METHODS: Oligo 6.22 and Primer Premier 5.0 bio-soft were used to design 15 pairs of primers of mtRNA cDNA probes in light of the functional and structural property of mtDNA, and then RT-PCR amplification was used to produce 15 probes of mtRNA from one normal gastric mucosal tissue. Total RNA extracted from 9 gastric cancers and corresponding normal gastric mucosal tissues was reverse transcribed into cDNA labeled with fluorescein. The spotted mtDNA microarrays were made and hybridized. Finally, the microarrays were scanned with a GeneTAC laser scanner to get the hybridized results. Northern blot was used to confirm the microarray results. RESULTS: The hybridized spots were distinct with clear and consistent backgrounds. After data was standardized according to the housekeeping genes, the results showed that the expression levels of some mitochondrial genes in gastric carcinoma were different from those in the corresponding non-cancerous regions. CONCLUSION: The mtDNA expression microarray can rapidly, massively and exactly detect the quantity of mtRNA in tissues and cells. In addition, the whole expressive information of mtRNA from a tumor patient on just one slide can be obtained using this method, providing an effective method to investigate the relationship between mtDNA expression and tumorigenesis.

Blotting, Northern↗

PubMed2005

Low dose suramin as a chemosensitizer of bladder cancer to mitomycin C.

PURPOSE: We have reported that acidic and basic fibroblast growth factors expressed in solid tumors induce broad-spectrum chemoresistance and their nonspecific inhibitor suramin (Sigma Chemical Co., St. Louis, Missouri) at nontoxic concentrations enhances the activity of chemotherapeutic agents. In the current study we evaluated whether low dose suramin enhances tumor sensitivity to mitomycin C (MMC) (Bristol-Myer Squibb Co., Wallingford, Connecticut). MATERIALS AND METHODS: Three-dimensional histocultures of RT4 (American Type Culture Collection, Rockville, Maryland) xenograft tumors and tumors from patients with bladder cancer were treated with MMC with or without 20 microM suramin. For in vivo studies mice bearing RT4 tumors received physiological saline, MMC (3 mg/kg), suramin (10 mg/kg) or MMC/suramin combination every 3 or 4 days. Two MMC schedules were studied, namely subtherapeutic (3 treatments) and therapeutic (6 treatments) schedules. RESULTS: Suramin enhanced MMC activity in xenograft and patient tumor histocultures by greater than 2-fold. The chemosensitization effect was observed in all patient tumors (2 superficial and 9 muscle invading lesions). In animals tumors in the control and suramin groups increased to approximately 3 to 5 times the initial size. The subtherapeutic MMC schedule retarded tumor growth but did not produce tumor shrinkage, whereas the therapeutic MMC schedule reduced tumor size by 27%. The addition of suramin enhanced MMC activity. Respective tumor sizes were 40% and 63% of the sizes after subtherapeutic and therapeutic MMC alone (p <0.01). The combination groups showed body weight losses similar to those of MMC alone. CONCLUSIONS: Low dose suramin enhanced the in vitro and in vivo activity of subtherapeutic and therapeutic MMC without enhancing host toxicity, thus, providing proof of concept for evaluating low dose suramin as a chemosensitizer with MMC in bladder cancer.

Animals↗

PubMed2005

[Mutation of mitochondrial 12S rRNA in gastric carcinomas and its significance].

OBJECTIVE: To detect the alterations of mitochondrial 12S rRNA in patients with gastric cancer, and further evaluate their effects on development of gastric carcinomas. METHODS: Mitochondrial 12S rRNA of 22 samples of gastric cancer tissues and 22 corresponding normal gastric mucosa taken from the distal portion of surgical specimens were PCR amplified, followed by direct DNA sequencing. Laser capture microdissection technique (LCM) was used to isolate cancerous cells and dysplastic cells from patients with specific mutations. Denaturing high-performance liquid chromatography (DHPLC) plus allele-specific PCR (AS-PCR), nest-PCR and polyacrylamide gel electrophoresis (PAGE) were applied to further evaluate this mutant property and quantitative difference of mutant type between cancerous and dysplastic cells. Finally, RNAdraw bio-soft was used to analyze the RNA secondary structure of mutant type 12S rRNA. RESULTS: Compared with mitomap database, some variations were firstly found, among which np652 G insertion and np716 T-G transversion were only found in cancers. There existed statistically significant difference in variant frequency of 12S rRNA between intestinal type and diffuse type of gastric carcinoma, 5/17 (29.4%) and 12/17 (70.6%) respectively (P < 0.05). DHPLC analysis showed that 12S rRNA np652 G insertion and np716 T-G transversion were heteroplasmic mutation. Variant frequency of 12S rRNA in cancer was higher than that in dysplasia (P < 0.01). 12S rRNA 652G insertion had more adverse effect on secondary structure stability of 12S rRNA than T-G transversion did. CONCLUSION: Highly variant frequency of mitochondrial 12S rRNA may be associated with intestinal type of gastric cancer. Most parts of variations exist in both cancer and normal tissues and may not be characteristic of tumor specificity. However np652 G insertion and np716 T-G transversion may possess some molecular significance on gastric cancerogenesis. During the process of progression from normality through dysplasia to cancer, 12S rRNA tended to transit from homoplasmy (wild type) and heteroplasmy to homoplasmy (mutant type, np717 T-G).

Base Sequence↗

PubMed2004

Pathobiological significance of vascular endothelial growth factor and Maspin expressions in human gastric carcinoma.

AIM: To investigate the correlation between expression of vascular endothelial growth factor (VEGF) and cell differentiation, invasion, metastasis and Maspin expression in gastric carcinoma. METHODS: Formalin-fixed paraffin-embedded tissue specimens from 73 cases of gastric carcinoma were studied with SP immunohistochemistry, using anti-VEGF monoclonal antibody, and thirty-nine of them were studied using anti-Maspin monoclonal antibody. VEGF expression was compared with the clinical stage, lymph node metastasis, and Borrmann's and WHO's classification of gastric carcinoma. RESULTS: The positive rate of VEGF expression was significantly higher in adjacent non-carcinoma epithelia (ANCE) than in non-metaplastic, non-carcinoma gastric epithelia (NMNCE), which were at least 4 cm distant from the primary tumor (P = 0.000, chi2 = 73.03). The positive rate of VEGF expression was significantly higher in advanced gastric carcinoma (AGC) than in early gastric carcinoma (EGC) (P = 0.032, chi2 = 4.62). The positive rate of VEGF expression in gastric carcinomas with lymph node metastases was significantly higher than that in those without metastasis (P = 0.006, chi2 = 7.47). Maspin was weakly expressed in 16 out of 39 cases of NMNCE, and the positive immunoreaction was limited to gland cells of the stomach body. There was no significant correlation between the expression of VEGF and histological or gross classifications, and correlation between the expressions of VEGF and Maspin in gastric carcinoma (P = 0.648, chi2 = 0.21). CONCLUSION: Expression of VEGF is significantly correlated to the malignant biological behaviors of gastric carcinoma, but there is no significant correlation between the expression of VEGF and Maspin.

Adenocarcinoma, Mucinous↗

PubMed2004

Pathobiological behavior and molecular mechanism of signet ring cell carcinoma and mucinous adenocarcinoma of the stomach: a comparative study.

AIM: To elucidate the distinctive pathobiological behavior between signet ring cell carcinoma (SRC) and mucinous adenocarcinoma of the stomach. METHODS: Based on the histological growth patterns and cell-functional differentiation classifications of stomach carcinoma, we conducted a series of comparative studies. All paraffin-embedded and frozen blocks were collected from the files of Cancer Institute of China Medical University. On the basis of histopathological observation, we applied enzymatic and mucous histochemistry, immunohistochemistry, flow cytometry (FCM) and molecular biology to compare these two categories of gastric cancers in terms of the DNA ploidy, proliferative kinetics, the expression of gastric carcinoma associated gene product and instabilities of mitochondrial DNA (mtDNA). RESULTS: Gastric SRC was commonly seen in females below 45 years, mostly presenting diffuse growth and ovary or uterine cervix metastasis. The majority of SRC were absorptive and mucus-producing functional differentiation type (AMPFDT), which growth relied on estrogen. Meanwhile, stomach mucinous adenocarcinomas were mostly observed in males over 50 years, prone to massive growth or nest growth and extensive peritoneal infiltration, showing two categories of cell-functional differentiation types: AMPFDT and mucus-secreting functional differentiation type (MSFDT). Expressions of ER, enzyme c-PDE and 67kDaLN-R in SRC were evidently higher than that in mucinous adenocarcinoma, while expressions of LN, CN-IV, CD44v6, and PTEN protein were obviously lower in SRC than that in mucinous adenocarcinoma (P<0.05). There was no statistic significance in VEGF, ECD and instabilities of mtDNA (P>0.05) between the above two gastric carcinomas. CONCLUSION: Though SRC and mucinous adenocarcinoma were both characterized by abundant mucus-secretion, they were quite different in morphology, ultrastructure, cell-functional differentiation and protein expression, indicating different mechanisms of carcinogenesis. We concluded that combining histological growth patterns, cell-functional differentiation type with tumor related markers might be significant in early diagnosis and prognosis assessment for SRC and mucinous adenocarcinoma of the stomach.

Adenocarcinoma, Mucinous↗

PubMed2004

[Quantitation and detection of deletion in tumor mitochondrial DNA by microarray technique].

OBJECTIVE: To develop a method to rapidly quantitate and detect deletion of mitochondrial DNA (mtDNA) by microarray technique as a tool to study its relationship to tumorigenesis. METHODS: A modified PCR was used to amplify full length mtDNA sequence in two samples of normal human blood leukocytes and five samples of gastric cancerous tissues, which were simultaneously labeled with fluorescin. The amplified products were verified by polyacrylamide gel electrophoresis (PAGE) and silver staining. Then, 17 pairs of overlapping primers of mtDNA were designed and their PCR products were used as mitochondrial probes. They were spotted onto amino-slides as microarray and hybridized. Hybridization image was scanned with GeneTAC laser, mtDNA copy number was counted by ScanAnalyzer software. RESULTS: PAGE analysis showed that the designed probes were quite reasonable and strongly specific. The modified PCR method was efficient to amplify the whole mitochondrial genome with high-yield specific bands. The hybridizing spots were distinct, and background was clear. The signals of negative probes were close to those of background, and there was no significant difference between them (P > 0.05). The results were identical to those in the designed experiment. There were no significant differences between the results when the same sample of blood leucocytes or cancer tissues repeatedly examined with the same positive probes (P > 0.05), while there were significant differences when different types of samples were examined (P < 0.01). The hybridizing signals were stable and most of the data distributed in the range of mean +/- 2xSD. CONCLUSION: The method here reported can rapidly, correctly and massively determine whether there exist special deletion and/or quantitative changes of mtDNA in patients with tumors. It will be helpful for the study of the relationship between mtDNA alteration and tumor development.

DNA, Mitochondrial↗

PubMed2004

Expression of PTEN and Caspase-3 and their clinicopathological significance in primary gastric malignant lymphoma.

OBJECTIVE: To investigate the expression of PTEN and Caspase-3 in malignant lymphoma of the stomach and explore their role in progression of primary gastric malignant lymphoma. METHODS: Formalin-fixed paraffin embedded tissues from 56 cases of primary gastric malignant lymphoma and their adjacent non-tumor mucosa were evaluated for PTEN and Caspase-3 protein expression by streptavidin-biotin-complex (SABC) immunohistochemistry. Their expression was compared with clinical tumor parameters with the relationship between PTEN and Caspase-3 expression concerned as well. RESULTS: The positive rate of PTEN expression in primary gastric lymphomas (50.0%, 28/56) was significantly lower than that in adjacent non-tumor gastric mucosa (96.4%, 27/28) (P < 0.05). Meanwhile, 43 of 56 (76.8%) gastric lymphomas indicated Caspase-3 expression, less than that in adjacent non-tumor mucosa (93.5%, 29/31) (P < 0.05). The expression of PTEN was negatively correlated with invasion and lymph node metastasis of gastric lymphoma (P < 0.05), while the Caspase-3 expression was negatively associated with the latter one (P < 0.05). Additionally, the PTEN expression was positively correlated with Caspase-3 expression in the primary gastric malignant lymphoma (P < 0.05). CONCLUSIONS: The down-regulated expression of PTEN and Caspase-3 played an important role in progression of primary malignant gastric lymphoma. PTEN, as a molecular marker of pathobiological behaviors of tumor, contributes to tumor progression by increasing cell mobility and angiogenesis, as well as decreasing cell adhesion and apoptosis.

Adult↗

PubMed2004

Effects of mutation and expression of PTEN gene mRNA on tumorigenesis and progression of epithelial 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 clinicopathological 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.

Adolescent↗

PubMed2004

[Altered expression of PTEN gene and LOH of its epigenetic microsatellite in gastric carcinoma].

OBJECTIVE: To investigate the expression of PTEN and loss of heterozygosity (LOH) of its epigenetic microsatellite in gastric carcinoma and explore their roles in progression of gastric carcinoma. METHODS: LOH of epigenetic microsatellites of PTEN (D10S541, D10S583 and D10S1687) in advanced gastric cancer was detected by PCR-SSCP. Expression of PTEN mRNA and protein in normal gastric mucosa and gastric cancer was evaluated by RT-PCR and SABC immunohistochemistry, respectively. The relationship between expression of PTEN mRNA and protein and lymph node metastasis or LOH of microsatellites was discussed. RESULTS: LOH of D10S541, D10S583 and D10S1687 was found in 37.5% (21/56) of advanced gastric cancers. The positive rates of PTEN mRNA expression were 80.4% (45/56), 45.5% (5/11) and 32.1% (18/56) in normal mucosa, early and advanced gastric carcinomas, respectively, while 78.6% (44/56), 44.5% (5/11) and 28.6% (16/56) at the protein level. PTEN mRNA and protein were less frequently expressed in early and advanced gastric carcinomas than that in normal gastric mucosa (P < 0.05). There was positive correlation between PTEN mRNA expression and LOH of microsatellites in advanced gastric carcinomas. PTEN protein expression paralleled with its mRNA expression (P < 0.05). The expression of PTEN mRNA and protein was negatively correlated with lymph node metastasis of advanced gastric carcinomas (P < 0.05). CONCLUSION: Down-regulated expression of PTEN gene is found in different stages of gastric carcinoma, and is closely correlated with LOH of its epigenetic microsatellites, which probably is its underlying molecular mechanisms. It suggests that altered PTEN gene contributes to tumorigenesis and progression of gastric carcinomas.

Gastric Mucosa↗

PubMed2004

Expression of maspin and kai1 and their clinicopathological significance in carcinogenesis and progression of gastric cancer.

OBJECTIVE: To investigate the roles of maspin and kai1 expression in tumorigenesis and progression of gastric cancer. METHODS: Maspin and kai1 expressions were detected in normal gastric mucosa (n = 182), gastric dysplasia (n = 69), and gastric cancer (n = 113) by immunohisto-chemistry. Their expressions were compared with clinicopathological parameters of tumors. Relationship between maspin and kai1 expression was also concerned in gastric cancer. RESULTS: The positive rates of maspin expression were 79.8% (145/182), 75.4% (52/69), and 50.4% (57/113) in normal gastric mucosa, gastric dysplasia, and gastric cancer, while those of kai1 expression were 81.9% (149/182), 65.2% (49/69), and 58.4% (66/113) in corresponding tissues respectively. Gastric cancer less frequently expressed maspin than the normal gastric mucosa and gastric dysplasia (P < 0.05), while dysplasia and cancer showed less frequent expression of kai1 than normal mucosa (P < 0.05). Maspin expression showed negative association with invasive depth, metastasis, Lauren's and histological classifications (P < 0.05), but not with tumor size, Borrmann's classification, growth pattern or TNM staging (P > 0.05). Kai1 expression was negatively correlated with invasive depth, metastasis, growth pattern, Lauren's and histological classifications (P < 0.05), but not with tumor size, Borrmann's classification or TNM staging (P > 0.05). Maspin and kai1 were collaboratively expressed in gastric cancer (P < 0.05). CONCLUSIONS: Down-regulated expressions of maspin and kai1 play an important role in gastric carcinogenesis. Abnormal expression of maspin and kai1 might have inhibitory effects on invasion and metastasis of gastric cancer and act as an effective and objective marker to indicate the pathobiological behaviors of gastric cancer.

Adenocarcinoma↗