人类癌细胞转化实验成功

经过15年的努力,研究人员已经成功地将培养皿中的正常人类细胞转化为肿瘤细胞。这一成就将有助于鉴定肿瘤转化过程中新的作用因子,而且有助于研究出针对这些致癌因素的防治方法。人们早已知道,肿瘤的形成历经多个步骤,包括遗传变异的逐渐积累。在肿瘤形成过程中会遇到很多细胞障碍,遗传变异可使细胞跨越这些障碍而癌变。但是直到现在,人们才能在培养皿里将正常人类细胞成功地转化为真正的肿瘤细胞。

食管鳞癌患者血清中lncRNA-TUSC7的表达及与细胞侵袭转移的关系

目的探究长链非编码lncRNA-TUSC7在食管鳞癌患者血清中表达的临床意义并进一步评估其对食管癌细胞侵袭和转移能力的影响。方法选取2017年1月~2019年5月南阳市第二人民医院和南阳市中心医院收治的60例食管鳞癌患者的血清,同时选取60例年龄、性别匹配的健康体检者血清作为对照组。采用RT-qPCR方法检测血清中TUSC7的表达,分析其与临床病理特征的关系。同时以正常食管上皮细胞为对照,检测4种食管鳞癌细胞系中TUSC7的表达,进一步通过体外过表达或抑制TUSC7,进行MTT,划痕实验和细胞侵袭实验分析TUSC7对细胞迁移及侵袭的影响。Western blot检测过表达或抑制TUSC7对食管鳞癌细胞上皮间质转化(EMT)的标志物(MMP-9、E-cadherin、N-cadherin和Vimentin)蛋白表达的影响。结果食管鳞癌患者血清中LncRNATUSC7的表达低于正常健康对照组(P<0.05);TUSC低表达与肿瘤分期、淋巴结转移及组织浸润程度相关(P<0.05)。细胞水平上实验组TUSC7表达水平低于对照组(P<0.05);过表达TUSC7可显著抑制食管癌细胞的迁移和侵袭能力(P<0.05);并提高KYSE-30细胞EMT相关蛋白E-cadherin,而降低MMP-9、N-cadherin和Vimentin蛋白表达量(P<0.05);而抑制TUSC7后结果相反。结论TUSC7在ESCC血清和细胞系中表达下调,与食管鳞癌淋巴结转移相关,且具有通过EMT促进肿瘤细胞迁移和侵袭的功能。因此血清中TUSC7具有成为食管鳞癌诊疗和转移监测的分子标记物的可能。

Connective tissue growth factor is overexpressed in human hepatocellular carcinoma and promotes cell invasion and growth

AIM:To determine the expression characteristics of connective tissue growth factor(CTGF/CCN2) in human hepatocellular carcinoma(HCC) in histology and to elucidate the roles of CCN2 on hepatoma cell cycle progression and metastasis in vitro.METHODS:Liver samples from 36 patients(who underwent hepatic resection for the first HCC between 2006 and 2011) and 6 normal individuals were examined for transforming growth factor β1(TGF-β1) or CCN2 mRNA by in situ hybridization.Computer image analysis was performed to measure integrated optimal density of CCN2 mRNA-positive cells in carcinoma foci and the surrounding stroma.Fibroblast-specific protein-1(FSP-1) and E-cadherin were examined to evaluate the process of epithelial to mesenchymal transition,α-smooth muscle actin and FSP-1 were detected to identify hepatic stellate cells,and CD34 was measured to evaluate the extent of vascularization in liver tissues by immunohistochemical staining.CCN2 was assessed for its stimulation of HepG2 cell migration and invasion using commercial kits while flow cytometry was used to determine CCN2 effects on HepG2 cell-cycle.RESULTS:In situ hybridization analysis showed that TGF-β1 mRNA was mainly detected in connective tissues and vasculature around carcinoma foci.In comparison to normal controls,CCN2 mRNA was enhanced 1.9-fold in carcinoma foci(12.36 ± 6.08 vs 6.42 ± 2.35) or 9.4-fold in the surrounding stroma(60.27 ± 28.71 vs 6.42 ± 2.35),with concomitant expression of CCN2 and TGF-β1 mRNA in those areas.Epithelial-mesenchymal transition phenotype related with CCN2 was detected in 12/36(33.3%) of HCC liver samples at the edges between carcinoma foci and vasculature.Incubation of HepG2 cells with CCN2(100 ng/mL) resulted in more of the cells transitioning into S phase(23.85 ± 2.35 vs 10.94 ± 0.23),and induced a significant migratory(4.0-fold) and invasive(5.7-fold) effect.TGF-β1-induced cell invasion was abrogated by a neutralizing CCN2 antibody showing that CCN2 is a downstream mediator of TGF-β1-induced hepatoma cell invasion.CONCLUSION:These data support a role for CCN2 in the growth and metastasis of HCC and highlight CCN2 as a potential novel therapeutic target.

Influence of CO_2 pneumoperitoneum on intracellular pH and signal transduction in cancer cells

Object: The authors studied the influence of CO2 pneumoperitoneum on intracellular pH and signal transduction arising from cancer cell multiplication in laparoscopic tumor operation. Method: They set up a simulation of pneumoperitoneum under different CO2 pressure, and then measured the variation of intracellular pH (pHi) at different time and the activity of protein kinase C (PKC) and protein phosphatase 2a (PP2a) at the end of the pneumoperitoneum. After 1 week, the concentration of cancer cells in the culture medium was calculated. Result: When the pressure of CO2 pneumoperitoneum was 0, 10, 20, 30 mmHg respectively, the average pHi was 7.273, 7.075, 6.783, 6.693 at the end of the pneumoperitoneum; PKC activity was 159.4, 168.5,178.0, 181.6 nmol/(g.min) and PP2a was 4158.3, 4066.9, 3984.0, 3878.5 nmol/(g.min) respectively. After 1 week, the cancer cells concentration was 2.15×105, 2.03×105, 2.20×105, 2.18×105 L-1. Conclusion: CO2 pneumoperitoneum could promote acidosis in cancer cells, inducing the activation of protein kinase C and deactivation of protein phosphatase 2a, but it could not accelerate the mitosis rate of the cancer cells.

Effects of thalidomide on angiogenesis and tumor growth and metastasis of human hepatocellular carcinoma in nude mice

AIM: To investigate the effects of thalidomide on angiogenesis, tumor growth and metastasis of hepatocellular carcinoma in nude mice.METHODS: Twenty-four nude mice were randomly divided into therapy group and control group, 12 mice in each group. Thalidomide dissolved in 0.5% sodium carboxyl methyl cellulose (CMC) suspension was administered intraperitoneally once a day at the dose of 200 mg/kg in therapy group, and an equivalent volume of 0.5% CMC in control group. Mice were sacrificed on the 30th d, tumor size and weight and metastases in liver and lungs were measured. CD34 and VEGF mRNA in tumor tissue were detected by immunohistochemistry and semi-quantitative RT-PCR respectively and microvessel density (MVD) was counted. Serum concentrations of TNF-α and ALT and AFP were also tested.RESULTS: MVD and VEGF mRNA in therapy group were less than those in control group (31.08±16.23 vessels/HP vs 80.00±26.27 vessels/HP, 0.0538±0.0165 vs 0.7373±0.1297,respectively, P＜0.05). No statistical difference was observed in tumor size and weight and metastases in liver and lungs.TNF-α was significantly lower in therapy group than in control group (28.64±4.64 ng/L vs42.69±6.99 ng/L, P＜0.05). No statistical difference in ALT and AFP was observed between groups.CONCLUSION: Thalidomide can significantly inhibitangiogenesis and metastasis of hepatocellular carcinoma.Italso has inhibitory effects on circulating TNF-α.

Relative predictive factors for hepatocellular carcinoma after HBeAg seroconversion in HBV infection

AIM： To determine the predictive factors for hepatocellular carcinoma （HCC） development in patients after spontaneous or therapeutic HBeAg seroconversion. METHODS： In 48 patients who seroconverted to anti- HBe positive during follow-up, the background factors for HCC development were analyzed. RESULTS： HCC was developed in six patients during follow-up （average follow-up after HBeAg seroconversion： 10.9±5.4 years）. The incidence of HCC evaluated by Kaplan-Meier analysis was significantly higher in patients with abnormal aspartate aminotransferase （AST〉 40 IU/L） level, lower platelet counts （PLT〈10×10^4/IJL）, lower albumin level （Alb〈30 g/L）, positive HBV-DNA or older age at seroconversion （〉40 years）. However, lower platelet count was the only predictive factor for HCC development shown by multivariate proportional-hazard analysis. CONCLUSION： Active hepatitis or advanced hepatitis at HBeAg seroconversion or progressive hepatitis even after HBeAg seroconversion would be the risk factors for HCC development. These predictive factors should be taken into account in determining the frequency of biochemical study or imaging studies for HCC surveillance.

Apoptotic cell death and its relationship to gastric carcinogenesis

AIM: To investigate the apoptotic process of cells with in the intestinal metaplasia areas co-localizing with chronic gastritis and gastric carcinomas and to analyze the involvement of proteins regulating apoptosis in the process of intestinal metaplasia related gastric carcinogenesis. METHODS: Forty-two gastric carcinoma and seventeen chronic gastritis cases were included in this study. All cases were examined for the existence of intestinal metaplasia. Ten cases randomly selected from each group were processed for TUNEL assay. TUNEL positive cells within the intestinal metaplasia areas, co-localizing either to gastric carcinoma or chronic gastritis, were counted and converted to apoptotic indices. In addition, p53, bcl-2 and bax expression patterns within these tissues were analyzed on the basis of immunohistochemistry. RESULTS: Twenty-eight of the cases were intestinal and 14 of the cases were diffuse type adenocarcinomas. 64% (27/42) of the gastric carcinoma cases had intestinal metaplasia. Intestinal metaplasia co-localized more with intestinal type carcinomas compared with diffuse type carcinomas [75% (21/28) vs 42% (6/14), respectively; P ≤0.05]. The mean apoptotic index in tumor cells was 0.70±0.08. The mean apoptotic index in intestinal metaplasias co-localizing to tumors was significantly higher than that of intestinal metaplasias co-localizing to chronic gastritis (0.70±0.03 vs 0.09±0.01, respectively; P≤0.05). p53 positivity was not observed in areas of intestinal metaplasia adjacent to tumors or chronic gastritis. Intestinal metaplasia areas adjacent to tumors showed lower cytoplasmic bcl-2 positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [55.5% (15/27) vs 70.5% (12/17), respectively]. On the other hand, intestinal metaplasia areas adjacent to tumors showed significantly higher cytoplasmic bax positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [44.4% (12/27) vs 11.7% (2/17), respectively; P ≤0.05]. CONCLUSION: Existence of apoptotic cells on the basis of TUNEL positivity is shown in intestinal metaplasias co-localizing to both diffuse and intestinal type gastric cancers in this study. Our results also suggested bax expression dependent induction of apoptosis especially in intestinal metaplasia areas adjacent to tumors. These findings strongly support the involvement of apoptotic mechanisms in the process of gastric carcinogenesis especially in the transition from intestinal metaplasia to gastric cancer. It may be suggested that induction of apoptosis in intestinal metaplasia areas adjacent to tumors may involve different mechanisms than induction by chronic inflammation.

SEVEN CASES OF EPITHELIAL OVARIAN CARCINOMA WITH BRAIN METASTASIS

Objective To summarize the clinical characteristics, treatment, and prognosis of brain metastasis in patients with epithelial ovarian carcinoma. Metbods Retrospective analysis was conducted in 7 cases of brain metastases of epithelial ovarian carcinoma from January 1986 to March 2007 in Peking Union Medical College Hospital for summarizing therapy results and prognosisaffecting factors. Results Incidence of brain metastases of epithelial ovarian carcinoma was about 0. 66% （7/1 055 ）. Serous adenocarcinoma was the predominant pathological type in 4 cases and the subsequent was adenocarcinoma in 3 cases. All the patients were diagnosed at late stage, 6 cases with the International Federation of Gynecology and Obstetrics （HGO） stage Ⅲc and 1 with FIGO stage IV. The mean duration from diagnosis of ovarian carcinoma to brain metastasis was 32.7 ± 20. 0 months （range, 23-73 months）. Single metastasis focus occurred in 43% of cases and multiple metastases in 57% of cases. Fifty-seven percent of patients presented extracranial metastasis. Serum CA125 played a role in monitoring reoccur- rence and brain metastases. The average survival time was about 12 months. Better treatment with prolonged survival could be achieved by combination of operation and chemotherapy or combination of radiotherapy with chemotherapy. Concltusions As a rare condition, brain metastasis of epithelial ovarian carcinoma is rising in incidence with improved treatment of ovarian carcinoma and prolonged survival. However, brain metastasis indicates bad prognosis which can be improved by combined therapy.

Targeting of RhoE inhibits epithelial-mesenchymal transition during colorectal cancer cell migration

Objective Despite microRNA （miR-200b） being proved to promote the proliferation of colorectal cancer （CRC） cells, the relationship between miR-200b and epithelial-mesenchymal transition （EMT） of CRC cells remains poorly understood. The aim of the study was to investigate the relationship between miR-200b and EMT during CRC cell migration. Methods The effect of miR-200b on EMT-associated markers E-cadherin and vimentin was evaluated by western blot in CRC cells （SW620 and HT-29） by treatment with miR-200b mimics and inhibitors. A lucifer- ase reporter assay was employed to detect downstream targets of miR-200b. Transwell migration assays were used to detect CRC cell migration. Results Westem blots revealed that treatment with miR-200b mimics led to up-regulation of E-cadherin and down-regulation of vimentin, metalloproteinase （MMP）-9, and MMP-2, whereas treatment with miR- 200b inhibitor exhibited opposite effects on expression of E-cadherin and vimentin. Luciferase reporter assays demonstrated that RhoE （RND3） was targeted by miR-200b. Two predicted target sites of miR-200b were present in the 3＇-UTR of RhoE. Predicted target site 1 was from nucleotides 1584 to 1591, and site 2 was from nucleotides 1729 to 1735. RhoE knockdown cell lines were also established to investigate the impact of RhoE and miR-200b on EMT and cell migration. RhoE knockdown enhanced the effect of miR- 200b mimics, up-regulating E-cadherin and down-regulating vimentin. RhoE knockdown also inhibited cell migration. Furthermore, miR-200b mimic treatment further promoted the inhibitory effect of RhoE knock- down on cell migration.

Expression of c-erbB-2 and glutathione S-transferase-pi in hepatocellular carcinoma and its adjacent tissue

AIM： To investigate the possible role of c-erbB-2 and glutathione S-transferase （GST-Pi） in primary hepatocellular carcinogenesis and the relationship between liver hyperplastic nodule （LHN）, liver cirrhosis （LC）, and hepatocellular carcinoma （HCC）.METHODS： The expression of c-erbB-2 and GST-Pi was detected immunohistochemically in 42 tissue specimens of HCC and 77 specimens of its adjacent tissue.RESULTS： The positive expression of c-erbB-2 in LHN （28.6%） was significantly higher than that in LC （0%） （P = 0.032〈0.05）, but no significant difference was seen between HCC and LHN or LC （P〉0.05, X^2 = 0.002, 3.447）.The positive expression of GST-Pi in HCC （89.6%） or LHN （72.2%） was significantly higher than that in LC（22.9%, P〈0.001, ;X^2= 49.91, 16.96）. There was a significant difference between HCC and LHN （P〈0.05,X^2= 6.353）.CONCLUSION： The c-erbB-2 expression is an early event in the pathogenesis of HCC. GST-Pi may be a marker enzyme for immunohistochemical detection of human HCC and its preneoplastic lesions. LHN seems to be a preneoplastic lesion related to hepatocarcinogenesis.

Cerebral and pulmonary embolisms after transcatheter arterial chemoembolization for hepatocellular carcinoma

A cerebral lipiodol embolism is an extremely rare complication of transcatheter arterial chemoembolization for hepatocellular carcinoma. We present a case of cerebral lipiodol embolism that occurred after the third arterial chemoembolization, report the clinical and radiological findings, and review the medical literature.

IMMUNORESPONSES OF HUMANIZED SCID MICE TO HUMAN LUNG CANCER CELLS

HuPBLSCID mice were used to explore how they would response to human tumor cells of 80llMLC.Living 80llMLC cells appeared to be fetal to the the mice due to the production of human TNF- The hupBL-SCID mice did not generate any noticeable amount of specific human immunoglobulin either by single immunization with living 801/MLC cells or by repeated immunization with irradiated 80llMLC cells. Our preliminary experiments with huPBL-SCID mice showed that such chimeras would be a very useful models for tumor immunological researches.

Inflammation-and stress-related signaling pathways in hepatocarcinogenesis

It has been established that cancer can be promoted and exacerbated by inflammation.Hepatocellular carcinoma(HCC) is the fifth most common cancer worldwide,and its long-term prognosis remains poor.Although HCC is a complex and heterogeneous tumor with several genomic mutations,it usually develops in the context of chronic liver damage and inflammation,suggesting that understanding the mechanism(s) of inflammation-mediated hepatocarcinogenesis is essential for the treatment and prevention of HCC.Chronic liver damage induces a persistent cycle of necroinflammation and hepatocyte regeneration,resulting in genetic mutations in hepatocytes and expansion of initiated cells,eventually leading to HCC development.Recently,several inflammation-and stress-related signaling pathways have been identified as key players in these processes,which include the nuclear factor B,signal transducer and activator of transcription,and stress-activated mitogen-activated protein kinase pathways.Although these pathways may suggest potential therapeutic targets,they have a wide range of functions and complex crosstalk occurs among them.This review focuses on recent advances in our understanding of the roles of these signaling pathways in hepatocarcinogenesis.

Testicular cancer in patients after treatment of cryptorchidism

Objective: We summarized the relationship between the descent of a testicle into the scrotum and testicular cancer.Methods: Twenty-eight patients with testicular cancer after surgical treatment of cryptorchidism were retrospective analysis.Results: All patients were performed surgical treatment of cryptorchidism from 2 to 28 years old (median,12 years;average,16 years).Testicular cancer age ranged from 19 to 53 years (median,33 years;average,36 years).Malignant transformation occurred from 3 to 25 years of operation time (average,18 years).Twenty-seven cases of malignant cryptorchidism ipsilateral,contralateral malignancy in 1 case,27 cases were underwent radical resection of testicular cancer.Pathology diagnosis was mainly seminoma.Retroperitoneal lymph node dissection was done in 3 cases,18 cases were chemotherapy and radiotherapy in 3 cases.Conclusion: The undescended testicle is the most common genital malformation in boys.When diagnosed,it should be treated as early as possible,but successful treatment appears not to lessen the risk of testicular cancer,patients must be closely monitored follow-up.

Relationship between epithelial to mesenchymaltransition and chemoresistance of lung cancer

Objective： The aim of this study was to explore the correlation between epithelial to mesenchymal transition （EMT） and chemoresistance of non-small-cell lung cancer （NSCLC）. Methods： In vitro, the drug resistance index of cisplatin resistant lung adenocarcinoma cell line （A549/DDP） was detected by CCK-8 assay; the morphological change between A549/ DDP cells and lung adenocarcinoma cells （A549） was observed by phase contrast microscope; expression of EMT markers （including E-cadherin and vimentin） and resistance protein, excision repair cross-complementing 1 （ERCC1） was detected by immunocytochemistry. The expression of E-cadherin, vimentin and ERCC1 was investigated by immunohistochemistry in 120 cases of NSCLC, half of that were treated with pre-operative neoadjuvant chemotherapy （neoadjuvant chemotherapy group）, and the other underwent surgery alone （simple surgery group）. Results： There was a significant difference between the ICso （half maximal inhibitory concentration） of A549/DDP cells （5.20） and A549 cells （1.88） （P 〈 0.05）, and the drug resistance index of A549/DDP cells was 2.77. Compared with A549 cells, A549/DDP cells increased expression of ERCC1 （P 〈 0.05）. Moreover, A549/DDP cells showed morphological and phenotypic changes consistent with EMT： with spindle-shaped morphology, and decreased expression of E-cadherin and increased expression of vimentin. Immunohistochemistry showed significant positive correlation between the expression of ERCCI and vimentin （r = 0.496, 0.332, P 〈 0.05）, and significant negative correlation between the ERCCI and E-cadherin （r = -0.403, -0.295, P 〈 0.05） in neoadjuvant chemotherapy group and simple surgery group. In addition, compared with simple surgery group, the expression of ERCC1 （P = 0.003） and vimentin （P = 0.004） was significantly increased, and the expression of E-cadherin was decreased in neoadjuvant chemotherapy group （P = 0.032）. Cenclusion： A549/DDP cells acquired cisplatin-resistance and occurred EMT simultaneously; the phenomenon of chemoresistance and EMT was caused more easily in neoadjuvant chemotherapy group. As such, we further confirmed the close correlation between chemoresistance and EMT of NSCLC, and provided theoretical basis for the targeting therapy with EMT regulatory factor for chemoresistant NSCLC patients.

Cloning and characterization of human IC53-2,a novel CDK5 activator binding protein

We have identified IC53-2, a human homologue of the rat C53 gene from a human placenta cDNA library (GeneBank Accession No. AF217982). IC53-2 can bind to the CDK5 activator p35 by in vitro association assay. IC53-2 is mapped to human chromosome 17q21.31. The IC53-2 transcript is highly expressed in kidney, liver, skeletal muscle and placenta. It is abundantly expressed in SMMC-7721, C-33A, 3AO, A431and MCF-7 cancer cell lines by RT-PCR assay. Stable transfection of IC53-2 cDNA into the hepatocellularcarcinoma SMMC-7721 cell remarkably stimulates its growth in vitro. The above results indicate thatIC53-2 is a novel human gene, which may be involved in the regulation of cell proliferation.

Epithelial-Mesenchymal Transitions and the Expression of Twist in MCF-7/ADR, Human Multidrug-Resistant Breast Cancer Cells

OBJECTIVE To study the expression levels of Twist and epithelialmesenchymal transitions in multidrug-resistant MCF-7/ADR breast cancer cells, and to study the relationship between multidrug resistance （MDR） and metastatic potential of the cells. METHODS RT-PCR, immunohistochemical and Western blotting methods were used to examine the changes of expression levels of the transcription factor Twist, E-cadherin and N-cadherin in the MCF-7 breast cancer cell line and its multidrug-resistant variant, MCF-7/ADR. RESULTS In MCF-7 cells, the expression of E-cadherin can be detected, but there is no expression of Twist or N-cadherin. In MCF-7/ADR cells, E-cadherin expression is lost, but the expression of two other genes was significantly positive. CONCLUSION Epithelial-mesenchymal transitions induced by Twist, may have a relationship with enhanced invasion and metastatic potential during the development of multidrug-resistant MCF-7/ADR breast cancer cells.

Aberrant methylation of SPARC in human hepatocellular carcinoma and its clinical implication

AIM:To investigate the methylation status of secreted protein acidic and rich in cysteine(SPARC) in human hepatocellular carcinoma(HCC) and evaluate its clinical implication.METHODS:The methylation status of SPARC was analyzed in one HCC cell line(SMMC-7721) and 60 pairs of HCC and corresponding nontumorous tissues by methylation-specific polymerase chain reaction and bisulfite sequencing.The expression of SPARC mRNA and protein were examined by reverse transcription polymerase chain reaction and immunohistochemistry,respectively.The correlations between the methylation status and the gene expression,the clinicopathological parameters,as well as the prognosis after surgery were analyzed.RESULTS:In the SMMC-7721 cell line,the loss of SPARC expression was correlated with the aberrant methylation and could be reactivated by the demethylating agent 5-aza-2'-deoxycytidine.Methylation frequency of SPARC in HCC was significantly higher than that in the corresponding nontumorous tissues(45/60 vs 7/60,P < 0.001),and it was correlated with the pathological classification(P = 0.019).The downregulation of the SPARC mRNA expression in HCC was correlated with the SPARC methylation(P = 0.040).The patients with methylated SPARC had a poorer overall survival than those without methylated SPARC(28.0 mo vs 41.0 mo,P = 0.043).CONCLUSION:Aberrant methylation is an important mechanism for SPARC inactivation in HCC and SPARC methylation may be a promising biomarker for the diagnosis and prognosis of HCC.

Aberrant methylation and downregulation of sall3 in human hepatocellular carcinoma

AIM: To investigated whether sall3 transcription was regulated by promoter CpG island hypermethylation in hepatocellular carcinoma (HCC). METHODS: The cell lines Huh7, HepG2, SK-HEP1, SM-MC7721, Bel7402, QGY7703 and a cohort of 38 HCC tissue specimens and corresponding nontumorous tissues were subjected to analysis for sall3 promoter CpG island methylation and mRNA transcription. sall3 promoter CpG island methylation levels were determined using the MassARRAY platform and mRNA transcription levels of the gene were detected by quantitative realtime polymerase chain reaction.RESULTS: The levels of sall3 mRNA were decreased by more than twofold in 33 of 38 tumor tissues compared to adjacent noncancerous tissues. Among these 33 tumor tissues with lower levels of sall3 mRNA, 24 showed higher levels of methylation. Based on these results, we hypothesized that the decrease in sall3 mRNA transcription level was likely due to promoter CpG island hypermethylation. Changes in sall3 mRNA transcription and promoter CpG island methylation were determined in the above six cell lines after treatment with 0, 0.1, 0.5 and 2.5 mmol 5-aza-2-deoxycytidine, a demethylating agent. Promoter CpG island methylation levels de- creased in a dose-dependent manner in all six cell lines, while the mRNA transcription level increased dose-dependently in Huh7, HepG2, SK-HEP1 and SMMC7721 cells and irregularly in Bel7402 and QGY7703 cells. CONCLUSION: These results indicated that promoter CpG island hypermethylation contributes to the downregulation of sall3 mRNA transcription in HCC.

In Vitro transformation of LW13 rat liver epithelial cells

A rat liver epithelial cell line designated LW13 was established using a sequential sedimentation method. The cell line retained many normal properties of liver epithelial cells and showed some structural and functional features resembling those of liver parenchymal cells. LW13 cells became malignant after the introduction of exogenous transforming EJ Ha ras gene. Tumors produced by inoculation of the transformed cells into baby rats .contained areas of poorly differentiated hepatocellular carcinoma. In situ hybridization analysis confirmed the random rather than specific integration of exogenous ras gene into host chromosomes. Furthermore , an at least tenfold increase in the expression of the endogenous c myc gene was detected among transformed cell lines, suggesting the involvement of the c myc proto oncogene in the in vitro transformation of rat liver epithelial cells by EJ Ha ras oncogene.