EXPRESSION OF THE O^6－METHYLGUANINE－DNA METHYLTRANSFERASE GENE IN EIGHT HUMAN TUMOR CELL LINES

O6-methylguanine-DNA methyltransferase (MGMT) gene expression in 6 Mer+ (HeLa S3, SMMC-7721,SGC-7901, B-239, AGZY83-a, and Cc80 1) and 2 Mer- (SHG-44 , and HeLa MR) human tumor cell lines was examined. Southern blot analysis revealed no deletion, amplification, or rearrangement of the MGMT gene in these cell lines. However ,～ 1. 0 kb transcripts were detected in the 6 Mer+ cell lines but not in the 2 Mer-cell lines by Northern blot analysis. Furthermore,a rough correlation between MGMT activity and mRNA level in these cell lines was observed. These results suggest that transcriptional regulation of the MGMT gene is the molecular basis of the absence of MGMT activity in Mer-cell lines.

Human ovarian neoplasm cell CD147 stimulates production and activation of matrix metalloproteinases in co-cultures with mouse fibroblasts

Objective: To investigate the expression of CD147 on human ovarian neoplasm cell lines and its influence on production and activation of matrix metallproteinases(MMPs). Methods: The expression of CD147 on different human ovarian neoplasm cell lines was studied by western blotting. Co-culture was carried out to investigate the stimulative effect of the positive expression CD147 cell HO-8910 on the production of MMPs of fibroblast cell in vitro. Zymography and immune blotting were used to study the production and activity of positive MMPs, at the time, to explore the relation between CD147 and MMPs. Results: CD147 was positively presented in 2 ovarian neoplasm cell lines(HO-8910,3-AO), but in SKOV3, TC-1,NIN3T3 cell was negative. MMP-2 and MMP-9 were detected by HO-8910 cell line, mouse fibroblast cell and co-culture cells; but the expression in co-culture cell is obviously higher than individual cultures of each type alone.CD147 stimulated MMPs in dose-dependent manner. Conclusion: CD147 causes increased production and activation of MMP-2, MMP-9.CD147 is probably a indirect marker of some ovarian cancer cells with invasion and metastasis.

Effect of gastrin on protein kinase C and its subtype in human colon cancer cell line SW480

INTRODUCTIONGastrin is atrophic gastrointestinal hormone whichis secreted by G cell.Gastrin has long beenconsidered a growth stimulatory hormone formucosa of the gastrointestinal tract.The growthresponses of certain colorectal cancer cells,andxenografts,can be stimulated by endogenousgastrin.Protein kinase C (PKC) is a family ofisozymes that plays a crucial role in transducingsignals of many hormones,growth peptides,

Relationship between NRAGE and the radioresistance of esophageal carcinoma cellline TE13R120

Background and Objective: The mRNA levels of 59 genes, detected by cDNA microarray, were up-regulated in the radioresistant human esophageal cacinoma cell line TE13R120 as compared with its parental cell line TE13 before and after radiation, and the expression of NRAGE gene showed a gradually up-regulating tendency. This study aimed to further detect the differences of NRAGE gene and protein expression and apoptosis between TE13R120 and TE13 cells, and to investigate the relationship between the NRAGE and the radioresistance of TE13R120 cells and its mechanism. Methods: The two cell lines were irradiated by 60 Co γ-ray at different conditions. Reverse transcription- polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry were used to detect the expression of NRAGE. Flow cytometry (FCM) was used to detect the cell apoptosis before and after irradiation. Results: The mRNA level of NRAGE was higher in TE13R120 cells than in TE13 cells before and after irradiation (before radiation: 0.25 ± 0.03 vs. 0.49 ± 0.03; 4 Gy 4 h: 0.31 ± 0.03 vs. 0.53 ± 0.02; 4 Gy 16 h: 0.32 ± 0.04 vs. 0.59 ± 0.04; 4 Gy 24 h: 0.36 ± 0.05 vs. 0.72 ± 0.04; 2 Gy 12 h: 0.32 ± 0.02 vs. 0.64 ± 0.04; 6 Gy 12 h: 0.36 ± 0.02 vs. 0.79 ± 0.05; 10 Gy 12 h: 0.46 ± 0.04 vs. 0.85 ± 0.01; P < 0.01), and the mRNA level of NRAGE was increased gradually with the increase of radiation dose and time in the two cell lines (P < 0.05 and P < 0.01). Western blot results showed no difference of NRAGE protein level in cytoplasm between TE13R120 cells and TE13 cells before and after irradiation, but its level in nuclei was higher in TE13R120 cells than in TE13 cells at different radiation time and dosages. Immunocytochemistry showed similar results as Western blot. FCM showed no significant difference in apoptosis rate between TE13R120 and TE13 cells before and after radiation. Conclusion: NRAGE may play an important role in the radiation responses of the two cell lines, and may participate in the formation of radioresistance of TE13R120 cells by changing its subcellular localization, but its relationship with cell apoptosis has not been confirmed.

Effect of cell fusion on metastatic ability of mouse hepatocarcinoma cell lines

AIM To study the effect of cell fusion on metastatic ability of mouse hepatocarcinoma cells and the factors involved in the process of metastasis. METHODS By the method of successively increasing the concentrations, cell fusion and limit dilution, 8 Ag resistant cells were selected, and HGPRT - Hca P cells and eight cloned hybridoma cells were obtained. To observe their metastatic ability, they were inoculated into mice foodtaps and the drainage lymph nodes were examined under microscope. RESULTS The end concentration of 8 Ag which was used to select HGPRT deficient Hca P cells was 30mg/L . All the cells selected died in HAT culture medium in one week. Fused cells appeared approximately 9 days later. They were round, transparent and a little larger than their parental cells. Eight clones of hybridoma cells were obtained and named as PSH1 PSH8. The metastatic rate of HGPRT - Hca P cells and PSH7 cells was 28 6% and 71 4% respectively, the difference being significant ( P <0 05). The metastatic rate of other clones was no more than 20% and there was no significant difference from HGPRT - Hca P cells ( P >0 05). CONCLUSION In normal mice splenic lymphocytes, there are some factors that could inhibit tumor metastasis, however, there are some other factors accelerating tumor cells to metastasize. The establishment of PSH7 provides an experimental model which could be used to study the factors involved in metastasis.

Interaction between cisplatin,5-fluorouracil and vincristine on human hepatoma cell line (7721)

AIM To evaluate the killing effects of CDDP, 5-Fu and VCR on human hepaoma cell line (7721).METHODS The median-effect principle was used.RESULTS Killing effects of the individual drug were enhanced as the median concentration increased. Antagonism was produced when two drugs were used at a higher concentration (CI＞1), and synergism was achiened when CI＜1. Finally, the effect was influenced by both the ratios of drug concentration and the sequence of administration.CONCLUSION The drug administration order and drug concentrations are significant factors that need to be considered in clinical practice.INTRODUCTIONThe combined chemotherapy for malignant carcinoma is desired to produce efficacious synergism between each drug, alleviate side effects of drugs and delay drug resistance. Clinically, the interaction (namely synergism, summation and antagonism) of different anticancer drugs in combination is usually evaluated by Chou-Talalay′s combination index (i.e., median-effect principle)[1-9]. In this paper the combination effect between Cisplatin (Cis), 5-Fluorouracil (5-Flu) and Vincristine (VCR) on human hepatoma cell line 7721, was analyzed in vitro.

Determination of β-glucuronidase in human colorectal carcinoma cell lines

IM To study the relationship between βglucuronidase and the invasiveness of human colorectal carcinoma cell lines.METHODS Six colorectal carcinoma cell lines including three welldifferentiated (CX1, CCL 187, CCL 229) and three poorlydifferentiated ones (CCL 227, CCL 228, Clone A) were analyzed for βglucuronidase in the medium by Fischman′s method.RESULTS Low levels of βglucuronidase (activity range, 129 to 196μg/106 cells·h) were associated with the poorly invasive cells. This was in contrast to the elevated levels of the enzyme (246337μg/106·h) present in the medium derived from the more aggressive cells (CCL 227, CCL 228, Clone A, CCL 229).CONCLUSION The highly invasive colorectal carcinoma cells secreted higher levels of βglucuronidase than the poorly invasive ones, and the determination of secreted βglucuronidase might provide a useful in vitro measurement of the invasiveness of colorectal carcinoma.

Establishment and characterization of four human hepatocellular carcinoma cell lines containing hepatitis B virus DNA

AIM To investigate the characteristics of newly established four hepatocellular carcinoma cell lines (SNU 739, SNU 761, SNU 878 and SNU 886) from Korean hepatocellular cancer patients. METHODS Morphologic and genetic studies were done. RESULTS All four lines grew as a monolayer with an adherent pattern, and their doubling times ranged from 20 to 29 hours. The viability rate was relatively high (88%-94%). Neither mycoplasmal nor bacterial contamination was present. The lines showed different patterns in fingerprinting analysis. The hepatitis B virus (HBV) DNA was integrated in the genomes of all four lines, and in all of them HBx, HBc and HBs transcripts were detected by reverse transcriptase PCR methods. Among the three cell lines used as control (Hep 3B, SK Hep1 and Hep G2), only Hep 3B showed HBx expression, and this line was used as a HBV integrated control. The RNA of albumin was detected in three lines (SNU 761, SNU 878 and SNU 886), that of transferrin in two lines (SNU 878, SNU 886), and that of IGF Ⅱ was detected in none of the cell lines. CONCLUSION These well characterized cell lines may be very useful for studying the biology of hepatocellular carcinoma in association with the hepatitis B virus.

Expression of VEGF_(121)in gastric carcinoma MGC803 cell line

INTRODUCTIONVascular endothelial growth factor(VEGF)whichis also known as vascular permeability factor(VPF)is a heparin-binding,dimeric polypeptide growthfactor and a potent mitogen for endothelial cells.VEGF can stimulate the endothelial cell growth andenhance the motility through its two knownreceptors flt-1 and KDR.Acting through thesereceptors,VEGF may stimulate angiogenesis

Fourier transform infrared spectroscopy of gallbladder carcinoma cell line

BACKGROUND: Fourier transform infrared (FT-IR) spectroscopy is a physical method applied to the study of cellular changes at the molecular level in various normal and diseased human tissues, including cancer. This study was undertaken to establish a cellular basis for the diagnosis of carcinoma tissue, using FT-IR spectroscopy to study a carcinoma cell line and investigating the specific spectral features of the cell line. METHODS: The FT-IR spectra of cultured gallbladder carcinoma cells (GBC-SD) smeared on a BaF(2) window were measured with a Nicolet Magna750-II FT-IR spectrometer. A comparative study was subsequently carried out between the spectra of cultured gallbladder carcinoma cells and those of corresponding carcinoma tissue. RESULTS: Several infrared spectral features were obtained, and the results suggest that the spectral features of the carcinoma cell line reflect those of carcinoma tissue, though the latter are more complex, probably due to the intrinsic complexity of the tissue. CONCLUSION: The diagnosis of carcinoma tissue by FTIR spectroscopy has a sufficient cellular basis.

EXPRESSION AND REVERSION OF DRUG RESISTANCE-AND APOPTOSIS-RELATED GENES OF A DDP-RESISTANT LUNG ADENOCARCINOMA CELL LINE

Objective: To investigate the co-expression of drug resistance- and apoptosis-related genes of cisplatin (CDDP)-selected lung adenocarcinoma cell line A 549 DDP for compared to the parental cell line A549, and reverse of drug resistance by antisense s-oligodeoxynucleotides (S-ODNs) of differentially expressed genes. Methods: Sense and antisense S-ODN were transferred into A 549 DDP cells by lipofectin. The expression of drug resistance and apoptosis related genes was examined by RT-PCR, immunocytochemistry and flow cytometry, respectively. Apoptostic cells were identified by DNA electrophoresis and terminal deoxynucleotidyl transferase (TdT)-mediated biotin dUTP nick end-labeling(TUNEL). Drug resistance of tumor cells was detected by a cell viability (MTT) assay. Results: The expression of bcl-2 was positive and that of multidrug resistance-associated protein (MRP) at mRNA and protein level was increased in A 549 DDP compared to A549 cells. MDR1, c-myc and topoisomeras II (TOPO II) were similarly co-expressed in two cell lines. Both cell lines were negative for c-erbB-2 expression. In A 549 DDP cells, the expression of bcl-2 and MRP was significantly inhibited by their respective antisense S-ODNs. Antisense S-ODNs could also decrease significantly drug resistance of A 549 DDP cells to CDDP by promoting cell apoptosis. Conclusion: Both intrinsic and acquired drug resistance were involved in co-expression of multiple MDR-related genes in lung adenocarcinoma. Cooperation of bcl-2 and MRP genes appeared to play an important action to confer the resistance of A 549 DDP cells to CDDP. Their antisense S-ODNs are responsible for the decrease of drug resistance of this cell line by promoting apoptosis.

Up-Regulation of the Gap Junction Intercellular Communication by Tea Polyphenol in the Human Metastatie Lung Carcinoma Cell Line

Our previous study has proven that tea polyphenol has a role in lung neoplasms. The present communication was to investage the anti-proliferation effect of tea polyphenol on the PG cells, which was a high metastatic human lung carcinoma cell line, by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide (MTT) cell viability assay, and to study the change of intracellular calcium concentration, connexin43 (Cx43) expression, gap junctional intercellular communication (GJIC) and cell cycle distribution after the tea polyphenol treatment by laser scanning confocal microscopy and flow cytometry. The results showed that 1) tea polyphenol could kill the PG cells in a dose-depent manner via inhibiting the PG cell proliferation and blocking the PG cell cycle progression staying in G0/G1 phase and not transfering in S and G2/M phases to reduce the PG cell proliferation index;2) the increases of intracellular calcium concentration, GJIC and Cx43 expression were related with the tea polyphenol doses. The data suggested that tea polyphenol could inhibit the growth of PG cells, which mechanism was associated with the up-regulation of GJIC.

STUDY ON EFFECTS OF ARSENIC TRIOXIDE ON GASTRIC CANCER CELL LINES

Objective To evaluate the effects of arsenic trioxide (As-2O-3) on apoptosis and differentiation of gastric cancer cell lines (GCCL). Methods MKN45 and SGC7901 cells were treated with As-2O-3 at different concentrations, then the apoptosis rates and cell cycle were determined by flow cytometry assays, the morphologic changes were observed under fluorescence microscopy and electronic microscopy, and the gene expressions were tested with immunohistologic staining. Results Higher apoptosis rates of GCCL were seen in the As-2O-3-treated group at concentrations of 5μmol and 10μmol, as compared with those in the 5-Fu-treated group. Cell-nuclear pyknosis and chromosomal condensation were observed. The As-2O-3 at a concentration of 0.5 μmol could induce the cell cycle changes of GCCL, revealing an increase in the proportion of G1/G0 phase cells and a decrease in the proportion of S phase cells. From the fifth day after treatment of SGC7901 with As-2O-3 at a low concentration, P53 and bcl-XL genes expression rates were reduced, Bax gene expression rate increased, and bcl-2 gene expression showed little change. Conclusion As-2O-3 could induce GCCL apoptosis at a high concentration and differentiation at a low concentration, but it could not completely reverse the malignant biological behaviours of cancer cells.

Effect of DRB on the Biological Characteristics of Human Laryngeal Carcinoma Hep-2 Cell Line

In order to study the effect of 5, 6-Dichloro-l-13-D-ribofuranosyl-benzimidazole （DRB） on the biological characteristics of human laryngeal carcinoma Hep-2 cell line in vitro, Hep-2 cells cultured in vitro were treated with different concentrations of DRB. Changes in cell proliferation, apoptotic rate and invasiveness were detected by MTT assay, flow cytometry （FCM） and matrigel in vitro invasion assay, respectively. It was found that DRB inhibited the proliferation of Hep-2 cells in a dose- and time-dependent manner. After being treated with 0, 10, 20, 40, 80 μmmol/L DRB for 24 h, the apoptotic rate in Hep-2 cells was （0.68±0.19）%, （1.95±0.12）%, （8.51±0.26）%, （11.26±0.17）% and （14.99±0.32）%, respectively. The matrigel in vitro invasion assay revealed that DRB began to inhibit the invasion of Hep-2 cells at the concentration of 5 μmmol/L, and with the increase of DRB concentration, the inhibitory effect was enhanced. It was suggested that DRB could influence the essential biological characteristics of Hep-2 cells, inhibit Hep-2 cells proliferation, reduce invasive ability and induce apoptosis of Hep-2 cells.

Construction of cell lines with CD44 cDNA and its application in hepatocellular carcinoma

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Retrovirus-mediated antisense RNA to bcl-2 alter the biological behavior of stomach carcinoma MGC-803 cell lines

AIM To demonstrate whether bcl 2 gene can affect or alter biological behavior of a stomach carcinoma cell line MGC 803. METHODS To transduct a retrovirus containing bcl 2 antisense RNA to MGC 803 cells and then to analyse the Bcl 2 protein expression in the cells by Western blotting. To observe the morphology alteration, detect the G1 phase arrest by FCM, inhibition of proliferation by MTT method and tumorigenicity in nude mice. RESULTS The MGC anti bcl 2 cells shows contact inhibition, morphological alteration, from round or near round to shuttle like, decelerated growth rate, G1 phase arrest and weakened tumorigenicity in nude mice unlike the control (MGC neo cells). CONCLUSION Antisense RNA to bcl 2, not only can induce apoptosis, but also reverse the biological behavior of MGC 803 cells. This would be a potential application to the gene therapy for stomach cancers.

RADIATION-INDUCED APOPTOSIS OF TWO NASOPHARANGEALCARCINOMA CELL LINES

Objective: To study apoptosis induced by radiation in two nasopharyngeal carcinoma (NPC) cell lines, CNE and CNE-2. Methods: Hoechst 33342 staining, immuno-histochemical staining, RT-PCR, DNA dot blotting and Southern blotting were used to identify apoptosis. Results: A single dose of X-irradiation resulted in apoptosis, the apoptotic index (AI) was time- and dose-dependent. Different apoptotic responses existed in the two cell lines. Immunohistochemical staining showed that bcl-2 protein was strongly positive in CNE but negative in CNE-2. However, RT-PCR revealed p53 mRNA in CNE-2 but not in CNE. P53 and bcl-2 genes were both present in the two cell lines as shown by DNA blotting, but the 2.8 kb fragment of the p53 gene was much lower than the 5.6 kb fragment on CNE which was clearly shown in Southern hybridization, suggestive of partial deletion of p53 gene in CNE. Conclusion: Apoptotic response to radiation is different in two NPC cell lines. CNE is more radioresistant than CNE-2. Overexpression of bcl-2 protein and partial deletion of p53 gene may explain their difference in radiosensitivity.

细胞外基质硬度对人前列腺癌细胞可塑性调控作用的研究

目的探讨细胞外基质硬度对人前列腺癌细胞LNCaP可塑性调控的作用。方法将人LNCaP细胞分别于杨氏模量为3 GPa(A组)、20 kPa(B组)、6 kPa(C组)和1 kPa(D组)四种不同硬度细胞外基质培养皿中培养1周。采用明场显微镜及荧光显微镜观察各组细胞在不同硬度基底上的形态;采用实时荧光定量聚合酶链反应(RT-qPCR)技术检测各组细胞的管腔细胞标志物基因AR、CK 8、CK 18、PSA,基底细胞标志物基因CK 5、P 63,以及增殖基因KI 67、PCNA的表达水平。结果明场显微镜及荧光显微镜观察结果显示,A组人LNCaP细胞呈现典型铺展上皮细胞形态,而B~D组均呈现团聚小细胞片状态,且D组细胞形成了三维类器官结构。RT-qPCR结果显示,四组人LNCaP细胞中KI 67、P 63基因表达水平无显著差异(P>0.05);B组PCNA基因表达水平显著高于A、C组(F=34.96,t=8.39、6.37,P<0.05);B组CK 5基因表达水平显著高于其他三组(F=29.35,t=4.46~6.73,P<0.05);D组AR、CK 8、CK 18、PSA基因表达水平显著高于其他三组(F=13.66~56.43,t=3.03~11.51,P<0.05)。结论硬度较低(杨氏模量1 kPa)的细胞外基质环境能较好维持人LNCaP细胞的管腔细胞特征,而硬度较高(杨氏模量20 kPa)的细胞外基质能使人LNCaP细胞呈现出中间态细胞表型,或许是导致前列腺癌发生的因素之一。

核糖体调控因子1对人乳腺癌MDA-MB-468细胞增殖和转移能力的影响

目的探讨核糖体合成调控因子1(RRS1)对人乳腺癌细胞增殖和转移能力的影响。方法通过Western Blot实验检测人乳腺癌细胞系(MDA-MB-231、MDA-MB-468、BT549、MCF-7细胞)以及正常人乳腺上皮细胞中RRS1蛋白的表达量;将MDA-MB-468细胞分别感染sh-RRS1慢病毒(sh-RRS1组)和阴性对照慢病毒(Con组),未进行任何感染的MDA-MB-468细胞为Blank组,在荧光显微镜下观察Con组和sh-RRS1组慢病毒感染效率,采用实时荧光定量PCR(RT-qPCR)技术和Western Blot实验分别检测各组细胞中RRS 1 mRNA和蛋白的表达水平;采用CCK-8实验检测RRS1对MDA-MB-468细胞活力的影响;采用划痕实验、Transwell实验以及侵袭实验检测RRS1对MDA-MB-468细胞侵袭和迁移能力的影响。结果各乳腺癌细胞系中RRS1的表达水平均明显高于正常人乳腺上皮细胞(F=28.71,P<0.05);相较于Blank组和Con组,sh-RRS1组细胞中RRS 1 mRNA和蛋白的表达水平均显著降低(F=118.10、335.40,P<0.05),细胞增殖活力明显减弱(F=825.60~2839.00,P<0.05),侵袭和迁移能力明显降低(F=25.60~430.80,P<0.05)。结论RRS 1基因可能参与了乳腺癌细胞的增殖和转移过程,其作用可能与细胞中RRS 1的高表达有关。