The role of tazarotene-induced gene 1 in carcinogenesis:is it a tumor suppressor gene or an oncogene?

Tazarotene-induced gene 1(TIG1)is induced by a derivative of vitamin A and is known to regulate many important biological processes and control the development of cancer.TIG1 is widely expressed in various tissues;yet in many cancer tissues,it is not expressed because of the methylation of its promoter.Additionally,the expression of TIG1 in cancer cells inhibits their growth and invasion,suggesting that TIG1 acts as a tumor suppressor gene.However,in some cancers,poor prognosis is associated with TIG1 expression,indicating its protumor growth characteristics,especially in promoting the invasion of inflammatory breast cancer cells.This review comprehensively summarizes the roles of the TIG1 gene in cancer development and details the mechanisms through which TIG1 regulates cancer development,with the aim of understanding its various roles in cancer development.

Wilm′s tumor gene1肽疫苗Galinpepimut-S在肿瘤免疫治疗中的应用

目的为Wilm′s tumor gene1(WT1)肽疫苗Galinpepimut-S(GPS)用于肿瘤免疫治疗的后续研究提供参考。方法采用计算机检索中国知网、PubMed等数据库自建库起至2022年12月的肿瘤免疫治疗相关文献,总结GPS在肿瘤免疫治疗中的应用现状。结果GPS能激发自身免疫系统,对WT1抗原产生强烈免疫反应而发挥抗肿瘤作用,在卵巢癌、恶性胸膜间皮瘤、急性髓系白血病、多发性骨髓瘤的治疗中均显示出较好的疗效。结论以GPS为代表的肿瘤疫苗是未来肿瘤治疗的重要方向,需进一步进行临床研究,以获取更多数据。

miR-30a-5p/PHTF2 axis regulates the tumorigenesis and metastasis of lung adenocarcinoma

Background:Lung adenocarcinoma is a very pervasive histological form of lung cancers,and inhibiting metastasis is crucial for effective treatment.In this investigation,we explored the functional interaction of miR-30a-5p and the putative transcription factor 2 of the homeodomain(PHTF2)in dictating the aggressiveness and metastasis of lung adenocarcinoma.Method:We collected clinical samples to evaluate the expression patterns of miR-30a-5p and PHTF2 in lung adenocarcinoma along with normal tissues.Cellular experiments including cell count kit(CCK)-8 growth assay,apoptosis analysis,migration and invasion examinations were performed to assess the aggressiveness of lung adenocarcinoma cells.Furthermore,we examined tumorigenesis and metastasis in a nude mouse model.Results:MiR-30a-5p exhibited downregulation pattern in lung adenocarcinoma samples.Transfection of miR-30a-5p mimic in lung adenocarcinoma cells resulted in the suppression of malignant characteristics.Notably,the administration of miR-30a-5p mimic also curbed tumorigenesis and metastasis of lung adenocarcinoma cells in animal model.Moreover,PHTF2 was found to be a molecular target of miR-30a-5p.Upregulating PHTF2 counteracted the tumor-suppressive effect of the miR-30a-5p mimic.Conclusion:miR-30a-5p functions as a tumor-suppressive molecule while PHTF2 acts as an oncogenic factor in the development and metastasis of lung adenocarcinoma.Therefore,targeting miR-30a-5p and PHTF2 could be developed into a promising therapeutic approach for inhibiting metastasis in lung adenocarcinoma.

LATS1 Promotes B-ALL Tumorigenesis by Regulating YAP1 Phosphorylation and Subcellular Localization

Objective YAP1 plays a dual role as an oncogene and tumor suppressor gene in several tumors;differentiating between these roles may depend on the YAP1 phosphorylation pattern.The specific function of YAP1 in B cell acute lymphoblastic leukemia(B-ALL),however,is currently unclear.Thus,in the present study,the role of YAP1 in B-ALL was investigated using relevant cell lines and patient datasets.Methods The effects of shRNA-mediated knockdown on YAP1 and LATS1 levels in the NALM6 and MOLT-4 cell lines were examined using Western blotting,quantitative real-time polymerase chain reaction,flow cytometry,immunostaining,and nude mouse subcutaneous tumorigenesis experiments.Gene expression levels of Hippo pathway-related molecules before and after verteporfin(VP)treatment were compared using RNA-Seq to identify significant Hippo pathway-related genes in NALM6 cells.Results Patients with ALL showing high YAP1 expression and low YAP1-Ser127 phosphorylation levels had worse prognoses than those with low YAP1 protein expression and high YAP1-Ser127 phosphorylation levels.YAP1-Ser127 phosphorylation levels were lower in NALM6 cells than in MOLT-4 and control cells;YAP1 was distributed in the nuclei in NALM6 cells.Knockdown of YAP1 inhibited MOLT-4 and NALM6 cell proliferation and arrested the NALM6 cell cycle in the G0/G1 phase.Before and after VP treatment,the expression of the upstream gene LATS1 was upregulated;its overexpression promoted YAP1-Ser127 phosphorylation.Further,YAP1 was distributed in the plasma.Conclusion LATS1 may downregulate YAP1-Ser127 phosphorylation and maintain B-ALL cell function;thus,VP,which targets this axis,may serve as a new therapeutic method for improving the outcomes for B-ALL patients.

Relationship of ultrasonic shear wave velocity with oncogene and tumor suppressor gene expression in primary liver cancer lesions as well as angiogenesis factor contents

Objective:To discuss the relationship of ultrasonic shear wave velocity (SWV) with oncogene and tumor suppressor gene expression in primary liver cancer lesions as well as angiogenesis factor contents.Methods:100 patients with primary liver cancer who underwent surgical treatment in our hospital between March 2014 and September 2016 were collected as observation group, and 50 healthy subjects who received physical examination in our hospital during the same period were collected as normal control group. The ultrasonic SWV levels of two groups of subjects were measured before the operation, and the observation groups were further divided into high SWV group and low SWV group, 50 cases in each group. Intraoperative tumor tissue samples were kept and fluorescence quantitative PCR was used to determine the mRNA expression of oncogenes and tumor suppressor genes. Enzyme-linked immunosorbent assay was used to determine serum contents of angiogenesis factors in observation group before operation.Results:Hepatic ultrasonic SWV level in observation group was significantly higher than that in normal control group;proto-oncogene CK, Ki67, Gly-3, Survivin and Pokemon mRNA expression in tumor tissue of high SWV group were higher than those of low SWV group while tumor suppressor genes Tg737, p16, p27, PTEN and runx3 mRNA expression were lower than those of low SWV group;serum angiogenesis factors VEGF, MMP-9 and IGF-1R contents were higher than those in low SWV group. Conclusion: The hepatic ultrasonic SWV level increases in patients with primary liver cancer, and the SWV level is directly correlated with oncogene and tumor suppressor gene expression as well as angiogenesis factor contents.

Aberrant Methylation in CpG Islands of pl5 and pl6 Tumor Suppressor Genes in Pancreatic Cancer Tissue

Objective： To detect the aberrant methylation patterns in the CpG islands of p16 and p15 tumor suppressor genes, and to analyze its correlation with pancreatic carcinogenesis and with clinicopathological characteristics of patients with pancreatic cancer （PC）. Methods： The methylation-specific polymerase chain reaction （MSP） method was used to monitor methylation patterns in the CpG islands of p15 and p16 genes from 29 cases of PC and 3 cases of chronic pancreatitis （CP） paraffin-embedded tissue, as well as 2 cases of normal liver tissues and 12 cases of normal blood samples. Results： p15 and p16 genes were detected to show unmethylation patterns and no amplification using methylation-specific primers in control group. The aberrant methylation rates of p16 in carcinoma tissue and adjacent noncarcinoma tissue were 37.9% （11 of 29 cases） and 34.5% （10 of 29 cases） respectively. Of the 11 aberrant methylated samples, 5 showed complete methylation and 6 hemimethylation. The methylation rates of p15 gene in carcinoma tissue and adjacent noncarcinoma tissue were 27.5% （8/29） and 24.4% （7/29） respectively. Of the 8 aberrant methylated samples, 3 showed complete methylation and 5 hemimethylation. In 6 PC samples, aberrant methylation in CpG islands of both p15 and p16 genes existed simultaneously. The aberrant methylation patterns in CpG islands of p15 and p16 genes had no close correlation with the clinicopathological characteristics （age, sex, smoking, volume of primary tumor, differentiation, clinical stage and histological classification） of the patients with PC （P〉0.05）. Conclusion： The aberrant methylation in CpG islands of p15 and p16 genes could be regarded as an early molecular event in PC and had no close correlation with the clinicopathological characteristics of the patients with PC.

Alteration of tumor suppressor gene p16 and Rb in gastric cancinogesis

IM To study the alterations of tumor suppressor gene p16 and Rb in the carcinogenesis of the stomach. METHODS Different mucosal biopsies were endoscopically obtained, all samples were immediately fixed with 10% buffered formalin, embedded with paraffin and sectioned serielly. Alterations of p16 and Rb protein in 12 cases of superficial gastritis, 15 atrophic gastritis, 20 atypical hyperplasia and 40 cancerous tissues were detected by the immunohistochemical method (ABC). RESULTS Different degrees of nuclear immunostaining of p16 and Rb occurred on gastric epithelium in different stages of lesions. With the lesions progressing, the positive immunostaining rate of p16 protein had a decreasing tendency (833%→733%→300%→275%), and on the other hand, that of Rb protein had an increasing tendency (250%→467%→600%→675%). A negative correlationship was found between these two parameters in the gastric cancer. Of 40 cases of gastric cancer, a negative relationship was observed in 20 cases. In comparison with both positive (9 cases) and both negative tissues (11 cases), there was a significant difference (500%,225%,275%) (P<005).CONCLUSION Abnormal expression of p16 and Rb plays an important role in gastric carcinogenesis.

A review of the literature on the use of CRISPR/Cas9 gene therapy to treat hepatocellular carcinoma

Noncoding RNAs instruct the Cas9 nuclease to site speifillyl cleave DNA in the CRISPR/Cas9 system.Despite the high incidence of hepatocellular carcinoma(HCC),the patient's outcome is poor.As a result of the emergence of therapeutic resistance in HCC patients,dlinicians have faced difficulties in treating such tumor.In addition,CRISPR/Cas9 screens were used to identify genes that improve the dlinical response of HCC patients.It is the objective of this article to summarize the current understanding of the use of the CRISPR/Cas9 system for the treatment of cancer,with a particular emphasis on HCC as part of the current state of knowledge.Thus,in order to locate recent developments in oncology research,we examined both the Scopus database and the PubMed database.The ability to selectively interfere with gene expression in combinatorial CRISPR/Cas9 screening can lead to the discovery of new effective HCC treatment regimens by combining clinically approved drugs.Drug resistance can be overcome with the help of the CRISPR/Cas9 system.HCC signature genes and resistance to treatment have been uncovered by genome-scale CRISPR activation screening although this method is not without limitations.It has been extensively examined whether CRISPR can be used as a tool for disease research and gene therapy.CRISPR and its applications to tumor research,particularly in HCC,are examined in this study through a review of the literature.

Cloning and Expression Analysis of a Human Putative Tumor Suppressor Gene Homologue from Rice

A gene homologous to the human Putative tumor suppressor gone QM, designated OSQM1, was isolated from rice (Oryza sativa L.) genomic DNA library using through homology screening. It contained 4 exons and 3 introns, encoding a protein of 219 amino acids with 46 basic amino acids, leading to a high isoelectric point of 11.02. Homology search showed that this gene existed in eukaryotes and highly conserved throughout eukaryotes, suggesting an essential role of this gene. Northern Not analysis showed that it was expressed in various rice organs, but at lower level in developing flower and callus tissue than in other vegetative organs. Its expression levels in roots and leaves were influenced by different environmental factors.

Overexpression and mutations of tumor suppressor gene p53 in hepatocellular carcinoma

AIMS To examine the prevalance of p53 mutations in hepatocellular carcinoma (HCC) from Chongqing area and the relationship between the p53 mutations and clinicopathological features of HCC,as well as the risk factors. METHODS The overexpression and point mutations of tumor suppressor gene p53 in 38 cases of HCC were detected by a sensitive antigen retrieval fluid (ARF) immunohistochemical method and polymerase chain re- action(PCR)-restriction fragment length polymorphism (RFLP),and single strand conformation polymorphism (SSCP)-silver staining analysis. RESULTS The results showed that 16 of 38 HCCs had positive p53 protein (42.1%),7 HCCs had p53 mutation at 249 (18.4 % ) and 2 HCCS had point muta- tion within exon 7 other than 249. Among 9 cases of HCC with mutations,8 cases demonstrated positive p53 protein,its coincidental rate was 88.9%. The overexpression and mutations of p53 were significantly related to the differentiation and metastasis of HCCs. The frequency of p53 mutations was consistent with high prevalence of HBV and a moderate aflatoxin B1 (AFB1) exposure in our area. CONCLUSIONS The results suggest that AFB1 acts synergistically with HBV in the generation of p53 mutations. Furthermore,dietary exposure to AFB1 may mainly contribute to the tumor specific mutation at codon 249,while HBV may account for other scattered mutations in HCC.

Prediction of Tumor Microenvironment Characteristics and Treatment Response in Lung Squamous Cell Carcinoma by Pseudogene OR7E47P-related Immune Genes

Objective Pseudogenes are initially regarded as nonfunctional genomic sequences,but some pseudogenes regulate tumor initiation and progression by interacting with other genes to modulate their transcriptional activities.Olfactory receptor family 7 subfamily E member 47 pseudogene(OR7E47P)is expressed broadly in lung tissues and has been identified as a positive regulator in the tumor microenvironment(TME)of lung adenocarcinoma(LUAD).This study aimed to elucidate the correlation between OR7E47P and tumor immunity in lung squamous cell carcinoma(LUSC).Methods Clinical and molecular information from The Cancer Genome Atlas(TCGA)LUSC cohort was used to identify OR7E47P-related immune genes(ORIGs)by weighted gene correlation network analysis(WGCNA).Based on the ORIGs,2 OR7E47P clusters were identified using non-negative matrix factorization(NMF)clustering,and the stability of the clustering was tested by an extreme gradient boosting classifier(XGBoost).LASSO-Cox and stepwise regressions were applied to further select prognostic ORIGs and to construct a predictive model(ORPScore)for immunotherapy.The Botling cohorts and 8 immunotherapy cohorts(the Samstein,Braun,Jung,Gide,IMvigor210,Lauss,Van Allen,and Cho cohorts)were included as independent validation cohorts.Results OR7E47P expression was positively correlated with immune cell infiltration and enrichment of immune-related pathways in LUSC.A total of 57 ORIGs were identified to classify the patients into 2 OR7E47P clusters(Cluster 1 and Cluster 2)with distinct immune,mutation,and stromal programs.Compared to Cluster 1,Cluster 2 had more infiltration by immune and stromal cells,lower mutation rates of driver genes,and higher expression of immune-related proteins.The clustering performed well in the internal and 5 external validation cohorts.Based on the 7 ORIGs(HOPX,STX2,WFS,DUSP22,SLFN13,GGCT,and CCSER2),the ORPScore was constructed to predict the prognosis and the treatment response.In addition,the ORPScore was a better prognostic factor and correlated positively with the immunotherapeutic response in cancer patients.The area under the curve values ranged from 0.584 to 0.805 in the 6 independent immunotherapy cohorts.Conclusion Our study suggests a significant correlation between OR7E47P and TME modulation in LUSC.ORIGs can be applied to molecularly stratify patients,and the ORPScore may serve as a biomarker for clinical decision-making regarding individualized prognostication and immunotherapy.

Bioinformatics Analysis Revealed Potential Tumor Suppressors (KLF4/CGN), Oncogenes (SHH/LIF) and Biomarkers of Asian Stomach Adenocarcinoma

Stomach adenocarcinoma (STAD) is the fifth most prevalent cancer and the third leading cause of cancer-related death in the world and is more common in Asia than in most Western countries. There is an urgent need to identify potential novel oncogenes and tumor suppressor genes, and biomarkers for STAD. 6652 differentially expressed genes were identified between STAD and normal samples based on the transcriptome data analysis of the TCGA and GEO databases. 13 key modules were identified in STAD by WGCNA analysis. 293 potential STAD associated genes were identified from intersection by Venn Diagram. The 293 intersected genes were enriched in cell cortex and infection by GO and KEGG analysis. 10 hub genes were identified from PPI and Cytoscape analyses of the intersected genes. KLF4/CGN low and SHH/LIF high expression were associated with short overall survival of Asian STAD patients. Bioinformatics analysis revealed potential novel tumor suppressors (KLF4/CGN), oncogenes (SHH/LIF) and biomarkers for diagnosis, therapy and prognosis of STAD, specifically for Asian patients.

Correlation research of Runt-related transcription factor 2 with proliferation genes, tumor suppressor genes and angiogenesis molecules in colon cancer lesions

Objective: To investigate the correlation of Runt-related transcription factor 2 (RunX2) with proliferation genes, tumor suppressor genes and angiogenesis molecules in colon cancer lesions. Methods: A total of 90 patients with primary colon cancer were enrolled in colon cancer group, 68 patients with benign colon polyps were enrolled in colon polyps group, the differences in the expression levels of RunX2, proliferation genes, tumor suppressor genes and angiogenesis molecules in the two groups of lesions were compared, and Pearson test was further used to evaluate the correlation of RunX2 expression level with proliferation gene, tumor suppressor gene and angiogenesis molecule expression levels in colon cancer tissues. Results: RunX2 mRNA expression level in the lesions of colon cancer group was higher than that of colon polyps group. Proliferation genes GTPBP4, HOXB7, ZNF331, ADAM17 and HSP60 mRNA expression levels in the lesions of colon cancer group were higher than those of colon polyps group;tumor suppressor genes ATF3, FOXN3, OTUD1 and NDRG2 mRNA expression levels were lower than those of colon polyps group;angiogenesis molecules Musashi 1, NF-κB, RegⅣ and STAT3 mRNA expression levels were higher than those of colon polyps group. RunX2 mRNA expression level in the colon cancer lesions was directly correlated with the expression levels of the above proliferation genes, tumor suppressor genes and angiogenesis molecules. Conclusion: RunX2 expression is abnormally high in colon cancer lesions, the specific expression level is positively correlated with cancer cell proliferation activity and angiogenesis activity, and it is an important molecular target that can lead to the occurrence and development of colon cancer.

Effect of cisplatin-based concurrent radiochemotherapy on malignant degree of advanced cervical cancer and expression of proto-oncogene and tumor suppressor genes

Objective:To study the effect of cisplatin-based concurrent radiochemotherapy on the malignant degree of advanced cervical cancer and the expression of proto-oncogene and tumor suppressor genes.Methods: A total of 82 patients with advanced cervical cancer who were treated in our hospital between July 2013 and December 2016 were collected and divided into control group and observation group according to random number table, with 41 cases in each group. The control group of patients received radiotherapy alone, while the observation group of patients received cisplatin-based concurrent radiochemotherapy. Tumor marker levels in serum as well as proto-oncogene and tumor suppressor gene expression in tumor tissue were compared between two groups of patients before and after treatment.Results:Before treatment, differences in tumor marker levels in serum as well as proto-oncogene and tumor suppressor gene expression in tumor tissue were not statistically significant between two groups of patients. After treatment, serum tumor markers SCC, CA50, CA724 and CEA levels of observation group were significantly lower than those of control group;proto-oncogene DEK, c-myc and PIK3CA mRNA expression in tumor tissue were significantly lower than those of control group;tumor suppressor genes p53, SOCS-1, FHIT and PTEN mRNA expression in tumor tissue were significantly higher than those of control group.Conclusions:Cisplatin-based concurrent radiochemotherapy can effectively reduce the tumor malignancy and balance the proto-oncogene / tumor suppressor gene expression in patients with advanced cervical cancer.

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].

Characterization of six tumorsuppressor genes and microsatellite instability in hepatocellular carcinomain southern African blacks

AIM To analyse cumulative loss of heterozygosity (LOH) of chromosomal regions and tumor suppressor genes in hepatocellular carcinomas (HCCs) from 20 southern African blacks. METHODS p53, RB1, BRCA1, BRCA2, WT1 and E cadherin genes were analysed for LOH, and p53 gene was also analysed for the codon 249 mutation, in tumor and adjacent non tumorous liver tissues using molecular techniques and 10 polymorphic microsatellite markers. RESULTS p53 codon 249 mutation was found in 25% of the subjects, as was expected, because many patients were from Mozambique, a country with high aflatoxin B 1 exposure. LOH was found at the RB1, BRCA2 and WT1 loci in 20%(4/*!20) of the HCCs, supporting a possible role of these genes in HCC. No LOH was evident in any of the remaining genes. Reports of mutations of p53 and RB1 genes in combination, described in other populations, were not confirmed in this study. Change in microsatellite repeat number was noted at 9/*!10 microsatellite loci in different HCCs, and changes at two or more loci were detected in 15%(3/*!20) of subjects. CONCLUSION We propose that microsatellite/genomic instability may play a role in the pathogenesis of a subset of HCCs in black Africans.

Inactivation of RASSF1A, the tumor suppressor gene at 3p21.3 in extrahepatic cholangiocarcinoma

AIM: To evaluate the genetic and epigenetic inactivation mechanism of the RASSF1A tumor suppressor gene at 3p21.3 in extrahepatic cholangiocarcinoma. METHODS: RT-PCR was used to investigate the transcriptional expressing and re-expression of RASSFIA. RASSFIA mutation was analyzed with SSCP and selective sequencing. PCR was performed to detect the loss of heterozygosity (LOH) at the region of chromosome 3p21.3. Genomic DNA were modificated bisulfite and the frequency of methylation of CpG islands in RASSFIA promoter were evaluated by methylation specific PCR (MS-PCR). RESULTS: In all 48 samples and one cell lines of extrahepatic cholangiocarcinoma, the RASSFIA mutation is rare (6.12%, 3/49), 33 samples (68.75%) and QBC-939 cell lines (X2= 14.270, P= 0.001<0.01) showed RASSFIA express inactivation with LOH at microsatellite loci D3S4604. Among these 33 samples and QBC-939, 28 of 33 (84.85%) tumor samples and 1 cell lines were methylated for majority of 16 CpGs, the average frequency is 73.42%. CONCLUSION: The data we present suggest that RASSFIA which we have been searching for at 3p21.3 may be one of the key tumor suppressor gene and play an important role in the pathogenesis of extrahepatic cholangiocarcinoma, and the promoter methylation and allelic loss are the major mechanism for inactivation of RASSFIA.

Potential roles of tumor suppressor genes and microsatellite instability in hepatocellular carcinogenesis in southern African blacks

MAJOR POINTS OF THE COMMENTED ARTICLECumulative loss of heterozygosity(LOH)ofchromosomal regions and tumor suppressor geneshas been reported in hepatocellular carcinomas(HCCs) from China,Japan,and Korea.In thisissue of the World Journal of Gastroenterology,Martins et al report an analysis of LOH andmicrosatellite instability in HCCs from a group of

Hepatocellular carcinoma mouse models:Hepatitis B virusassociatedhepatocarcinogenesis and haploinsufficienttumor suppressor genes

The multifactorial and multistage pathogenesis of hepatocellular carcinoma(HCC)has fascinated a wide spectrum of scientists for decades.While a number of major risk factors have been identified,their mechanistic roles in hepatocarcinogenesis still need to be elucidated.Many tumor suppressor genes(TSGs)have been identified as being involved in HCC.These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors:the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele.Hepatitis B virus(HBV)is one of the most important risk factors associated with HCC.Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor,one advantage of mouse models for HBV/HCC research is the numerous and powerfulgenetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs.Here,we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner.Discoveries obtained using mouse models will have a great impact on HCC translational medicine.

Reduction of tumorigenicity of SMMC-7721 hepatoma cells by vascular endothelial growth factor antisense gene therapy

AIM: To test the hypothesis to block VEGF expression of SMMC-7721 hepatoma cells may inhibit tumor growth using the rat hepatoma model. METHODS: Amplify the 200 VEGF cDNA fragment and insert it into human U6 gene cassette in the reverse orientation transcribing small antisense RNA which could specifically interact with VEGF165, and VEGF121 mRNA. Construct the retroviral vector containing this antisense VEGF U6 cassette and package the replication-deficient recombinant retrovirus. SMMC-7721 cells were transduced with these virus and positive clones were selected with G418. PCR and Southern blot analysis were performed to determine if U6 cassette integrated into the genomic DNA of positive clone. Transfected tumor cells were evaluated for RNA expression by ribonuclease protection assays. The VEGF protein in the supernatant of parental tumor cells and genetically modified tumor cells was determined with ELISA. In vitro and in vivo growth properties of antisense VEGF cell clone in nude mice were analyzed. RESULTS: Restriction enzyme digestion and PCR sequencing verified that the antisense VEGF RNA retroviral vector was successfully constructed.After G418 selection, resistant SMMC-7721 cell clone was picked up. PCR and Southern blot analysis suggested that U6 cassette was integrated into the cell genomic DNA. Stable SMMC-7721 cell clone transduced with U6 antisense RNA cassette could express 200 bp small antisense VEGF RNA and secrete reduced levels of VEGF in culture condition. Production of VEGF by antisense transgene-expressing cells was 65+/-10 ng/L per 10(6) cells, 42045 ng/L per 10(6) cells in sense group and 485+/-30 ng/L per 10(6) cells in the negative control group, (P【 0.05). The antisense-VEGF cell clone appeared phenotypically indistinguishable from SMMC-7721 cells and SMMC-7721 cells transfected sense VEGF. The growth rate of the antisense-VEGF cell clone was the same as the control cells. When S.C. was implanted into nude mice, growth of antisense-VEGF cell lines was greatly inhibited compared with control cells. CONCLUSION: Expression of antisense VEGF RNA in SMMC-7721 cells could decrease the tumorigenicity, and antisense-VEGF gene therapy may be an adjuvant treatment for hepatoma.