Enhancement of p53 gene transfer efficiency in hepatic tumor mediated by transferrin receptor through trans-arterial delivery

Transferrin-DNA complex mediated by transferrin receptor in combination with interventional trans-arterial injection into a target organ may be a duel-target-oriented delivery means to achieve an efficient gene therapy. In this study, transferrin receptor expression in normal human hepatocyte and two hepatocellular-carcinoma cells (Huh7/SK-Hep1) was determined. p53-LipofectAMINE with different amounts of transferrin was transfected into the cells and the gene transfection efficiency was evaluated. After VX2 rabbit hepatocarcinoma model was established, the transferrin-p53-LipofectAMINE complex was delivered into the hepatic artery via interventional techniques to analyze the therapeutic p53 gene transfer efficiency in vivo by Western blot, immunohistochemical/immunofluorescence staining analysis and survival time. The results were transferrin receptor expression in Huh7 and SK-Hep1 cells was higher than in normal hepatocyte. Transfection efficiency of p53 was increased in vitro in both Huh7 and SK-Hep1 cells with increasing transferrin in a dose-dependent manner. As compared to intravenous administration, interventional injection of p53-gene complex into hepatic tumor mediated by transferrin-receptor, could enhance the gene transfer efficiency in vivo as evaluated by Western blot, immunohistochemical/immunofluorenscence staining analyses and improved animal survival (H = 12.567, p = 0.0019). These findings show the transferrin-transferrin receptor system combined with interventional techniques enhanced p53-gene transfer to hepatic tumor and the duel-target-oriented gene delivery may be an effective approach for gene therapy.     

Hodgkin's cell lectin: an ectosialyltransferase and lymphocyte agglutinant related to the hepatic asialoglycoprotein receptor

The galactophilic lectin expressed on the surface of cultured Hodgkin's cells, recently described by this laboratory, has binding characteristics similar to those of the hepatic asialoglycoprotein receptor (HBP), and has been recognized as a Mr 55,000 (p55) membrane glycoprotein by a polyclonal antiserum to rat HBP. This study confirms the close structural relationship between the two lectins showing immunological cross-reactivity of monoclonal and polyclonal antibodies recognizing distinct epitopes on rat or human HBP. In support of the suggested dual nature of p55 as lectin and ectosialyltransferase, enzyme activity is inhibited by the monoclonal anti-HBP antibody, anti-HA 116. Cultured Hodgkin's cells, as purified HBP, agglutinate T-lymphocytes expressing hyposialylated membrane glycosyl determinants. This cell-cell interaction mediated by p55 results in the incorporation of sialic acid into lymphocyte surface asialo-glycans. The function of the Hodgkin's lectin as lymphocyte agglutinant in vitro suggests its role as an immunomodulator contributing to the immunodeficiencies associated with Hodgkin's disease.     

Inhibition of hepatocarcinoma and tumor metastasis to liver by gene therapy with recombinant CBD-HepII polypeptide of fibronectin

Unlike the intact fibronectin (FN) molecule, some proteolytic or recombinant fragments of FN possess inhibitory activities on tumor, providing potential strategies in tumor therapeutics. Using the hydrodynamics-based gene delivery technique, we demonstrated that the treatment by in vivo expression of a recombinant CBD-HepII polypeptide of FN, designated as CH50, strongly inhibited the tumor growth, tumor invasion and angiogenesis. Such inhibitory effects of CH50 on tumor were partly ascribed to its influence on the activities of MMP-9 and alphavbeta3 integrin. The in vivo expressed CH50 decreased both the production and the activity of MMP-9 in tumor tissues. CH50 also down-regulated alphavbeta3 expression in tumor cells and endothelial cells in vitro. The decreased activity of alphavbeta3 integrin was proved by its reduced binding ability to fibrinogen and the down-regulation of cdc2 expression. The gene therapy with CH50 not only prolonged the survival of mice bearing hepatocarcinoma in the liver, but also suppressed the growth and invasive ability of tumor in spleen and its metastasis to liver. Taken together, these findings suggest a prospective utility of CH50 in the gene therapy of liver cancer.     

Experimental Study of the Effect of the Bax Gene on Human Hepatocellular Carcinoma and Therapy via Hepatic Artery Delivery

OBJECTIVE To investigate apoptosis induced by Bax in hepatocellular carcinoma cells and to examine the results of 2 different routes for in vivo gene delivery.METHODS The anti-hepatocellular carcinoma activity of the Bax gene transferred to the human hepatocellular carcinoma QGY7703 cell line was examined. In addition the Bax gene was transferred in vivo in mice via the caudal vein or hepatic artery to investigate the differences in target organ and non-target organ transfection.RESULTS 1)The Bax gene mediated by a binary adenoviral vector system induced apoptosis in the human hepatic carcinoma QFY7703 cell line. The cell apoptotic rate in the experimental group (Bax) was 50.2± 6.9% but only 32.1 ± 9.7% in the Ad/CMV-p53 group, showing that the Bax-apoptotic rate was significantly higher than the control group. 2) LacZ expression was higher in the target organ (liver) when given through the hepatic artery than through the tail vein. In contrast, LacZ expression in the nontarget organs was higher if given through the tail vein compared to the hepatic artery.CONCLUSION Superselective hepatic artery delivery with Bax gene therapy is safe, specific, effective and has low toxicity. This study provided the basis for Bex-gene therapy via the hepatic artery in vivo.     

Apoptin gene transfer via modified wheat histone H4 facilitates apoptosis of human ovarian cancer cells

Nonviral approaches have been used extensively for intracellular gene transfer and gene therapy. A modified wheat histone H4 protein, H4TL (H4-TAT-LHRH), as a protein-based gene delivery vector that was able to form stable complexes with plasmid DNA and increase gene delivery efficiency has been described previously. In this study, H4TL has been used to deliver apoptin gene into a human ovarian carcinoma cell line HO8910. After transfection, increased expression of apoptin at both mRNA and protein levels was detected in HO8910 cells, accompanied by reduced rate of growth of HO8910 cells in vitro and the loss of mitochondrial membrane potential in these cells. These data demonstrate that H4TL-mediated transfer of apoptin initiates mitochondrial death pathway in ovarian cancer cells and suggest a novel therapeutic strategy for cancer.     

Modulation of asialoglycoprotein receptor levels in rat liver by phenobarbital treatment

The effect of the liver tumor promoter, phenobarbital, on thelevel of the asialoglycoprotein receptor (ASGP-R) was examinedin adult rat liver. ASGP-R, a liver-specific cell surface membraneprotein, was studied using antibody against this receptor togetherwith immunofluorescence techniques and radioreceptor assay withasialofetuin as the ligand. Both acute and chronic phenobarbitaladministration decreased the number of receptors per cell; partialhepatectomy had a similar effect on the number of receptorsper cell. However, after phenobarbital administration, the receptor-deficientareas were centrilobular, whereas after partial hepatectomy,ASGP-R positive and negative areas were intermingled throughoutthe liver lobule but were most pronounced in the periportalarea. Phenobarbital treatment, in contrast to its effect onthe ASGP-R level, did not change the cell surface binding ofconcanavalin A on rat hepatocytes. Four days after birth thenumber of hepatocytes with surface receptors was 50% of thatin the adult rats. At 10 days after birth the number of ASGP-Rpositive cells was the same as in adult rats, although the receptordensity was significantly lower than in adults. Treatment witha single dose of chemical carcinogen one day after birth combinedwith promotion by phenobarbital resulted in a significant reductionof ASGP-Rs in pre-neoplastic and neoplastic areas of livers.Whereas the pre-neoplastic and neoplastic areas displayed uniformreduction in the ASGP-R, normal parts of the liver showed receptor-deficiencyprimarily in the centrilobular areas.     

Tie2介导的基因导入系统转导p53基因对肺癌的抑制作用

目的：探讨Tie2介导的基因导入系统体内靶向转导p53基因治疗肺癌的效果。方法：应用双功能交联剂SMCC将Tie2配体寡肽GA3与PEI连接构建靶向Tie2的基因载体。体外试验将GA3-PEI/luciferase导入Tie2表达阳性的SPC-A1肺癌细胞与Tie2表达阴性的SMMC7721肝癌细胞中,24 h后检测luciferase活性。体内导入试验将GA3-PEI/β-gal复合物注射SPC-A1细胞裸鼠种植瘤周围皮下,同时设立PEI/β-gal组为对照;24 h后牺牲裸鼠,检测心、肝、脾、肺、肾和瘤体的β-gal表达。另外将另一批四周龄SPC-A1肺癌种植瘤裸鼠随机分为5组：（1）NS;（2）GA3;（3）p53;（4）PEI/p53;（5）GA3-PEI/p53;每组6只;皮下注射GA3-PEI/p53基因复合物,隔2天1次,并测量肿瘤长短径,计算瘤体积及抑瘤率。结果：GA3-PEI/luciferase组的luciferase活性在SPC-A1细胞中明显高于SMMC7721细胞（P〈0.05）。在种植瘤中可见较多蓝染细胞,心、肝、脾、肾组织中几乎不见篮染,肺支气管黏膜除外。与对照组比较,GA3-PEI/p53治疗组对肿瘤生长有明显抑制作用（P〈0.05）,其抑瘤率为61.29%。结论：GA3基因导入系统靶向转导p53基因,显著抑制肿瘤生长。     

Stimulation of mammary tumorigenesis by systemic tissue inhibitor of matrix metalloproteinase 4 gene delivery

Tissue inhibitors of matrix metalloproteinase (TIMPs) are multifunctional proteins with both matrix metalloproteinase (MMP) inhibitory effects and growth-regulatory activity. TIMPs inhibit MMP activity, suggesting a use for cancer gene therapy. However, here we report that systemic administration of human TIMP-4 by electroporation-mediated i.m. injection of naked TIMP-4 DNA stimulates tumorigenesis of human breast cancer cells in nude mice. Consistent with tumor stimulation, TIMP-4 up-regulates Bcl-2 and Bcl-X(L) protein. TIMP-4 also inhibits apoptosis in human breast cancer cells in vitro and mammary tumors in vivo. A synthetic MMP inhibitor BB-94 did not have such antiapoptotic effect. Analysis of TIMP-4 expression in human mammary specimens indicates that TIMP-4 protein is increased in mammary carcinoma cells compared with normal mammary epithelial cells. These data indicate an antiapoptotic activity in breast cancer cells and a tumor-stimulating effect of TIMP-4 when administrated systemically.     

Cationic lipid-based delivery system for systemic cancer gene therapy

A cationic lipid-based gene delivery system composed of N-[(1-(2,3-dioleyloxy)propyl)]-N-N-N-trimethylammonium chloride and cholesterol, at a 4:1 molar ratio, was developed for systemic administration. Plasmid biodistribution and expression were characterized in syngeneic mouse tumor model squamous cell carcinoma VII cells. A reporter gene expression plasmid was used for biodistribution of plasmid and expression. The results showed that lungs and primary tumors were transfected. Fluorescence microscopy showed that fluorescent-labeled transfection complexes were passively targeted to the tumor vasculature and that the endothelial cells internalized the plasmid. Transgene expression was characterized based on duration of expression and dosing schedule. In vivo gene transfer with an interleukin-12 expression plasmid yielded protein levels in blood, lungs, and primary tumor after intravenous administration. Efficacy studies showed that 15 microg of interleukin-12 plasmid was sufficient to produce a gene-specific inhibition of primary tumor growth. These results characterize the vascularity of the tumor model, characterize the in vivo gene transfer properties of the plasmid-based gene delivery system, and show that the transgene expression level was sufficient to elicit a biological response by inhibiting tumor growth.     

SOX30基因调控桥粒基因DSC3抑制肺腺癌的增殖与迁移

目的：探讨SOX30基因对桥粒基因DSC3的表达调控及其在肺腺癌发生中的作用。方法：利用基因功能富集分析（GO分析）获取SOX30调控的重要基因及通路;利用JASPAR数据库预测DSC3启动子区SOX30蛋白结合位点;利用TCGA数据库分析SOX30与DSC3在肺癌中表达的相关性,并用逆转录PCR检测A549细胞高表达SOX30后对DSC3 mRNA表达的影响;同时检测SOX30基因敲除小鼠肺组织中DSC3 mRNA的表达情况;利用平板细胞集落形成实验及细胞划痕愈合实验分析DSC3是否参与SOX30对肺腺癌细胞的增殖与迁移抑制。结果：GO分析显示SOX30基因与黏着斑、锚定连接、黏着连接等细胞连接基因表达显著相关;DSC3启动子区存在多个SOX30蛋白结合位点;SOX30与DSC3在肺腺癌中表达正相关（r=0.154,P=0.000）;高表达SOX30后,A549细胞中DSC3 mRNA水平较对照组显著上调（P < 0.05）;敲除SOX30基因后,纯合子（SOX30^-/-）小鼠肺组织中DSC3 mRNA水平显著低于杂合子（SOX30^+/-）及野生型（SOX30^+/+）小鼠（P均 < 0.01）;在高表达SOX30后的A549细胞中,干扰DSC3的表达后将显著减弱SOX30对A549细胞的增殖和迁移抑制（P均 < 0.05）。结论：SOX30是调控DSC3表达的关键分子,DSC3是SOX30发挥抑癌功能的重要下游基因,SOX30-DSC3调控可能在肺腺癌发生发展中起重要作用。     

Inhibition of tumorigenesis by intratumoral delivery of the circadian gene mPer2 in C57BL/6 mice

Biological clocks are intrinsic time-keeping systems that regulate behavior and physiological functions in most living organisms. Previous works suggested a possible link between the endogenous circadian clock and cell cycle regulation. The mammalian Period-2 gene (mPer2), an important component of the circadian clock mechanism, is recently demonstrated to play an important role in repressing tumor growth. In this study, we found that polyethylenimine-mediated intratumoral Per2 gene delivery had significant antitumor effects in C57BL/6 mice transplanted with Lewis lung carcinoma. Our data illustrated that the Per2 gene delivery inhibited PCNA expression and induced apoptosis. Our results support the emerging role of the circadian clock in critical aspects of tumorigenesis. These findings underscore the potential use of Per2 gene delivery as a novel therapeutic intervention for the treatment of malignant tumors.     

Inhibition of hepatic phosphoenolpyruvate carboxykinase by avian reticuloendotheliosis viruses

Severe weight loss is associated with many malignant diseases of humans and animals. Avian reticuloendotheliosis viruses (RE viruses) induce runting in experimentally infected chickens. Chickens infected with a replication-competent RE virus, reticuloendotheliosis-associated virus, weighed 30-50% less than control birds at the time of death. Chickens infected with reticuloendotheliosis virus, a replication-defective acute leukemia virus, weighed 30% less than the controls. The runting induced by RE viruses does not occur because of reduced food intake. Activities of phosphoenolpyruvate carboxykinase, a key gluconeogenic enzyme in the liver, were reduced approximately 40 and 50%, respectively, by infection with reticuloendotheliosis-associated virus and reticuloendotheliosis virus. RE virus infection, however, did not affect the hepatic pyruvate carboxylase activity, indicating that inhibition of phosphoenolpyruvate carboxykinase is not due to a general inhibition of all liver enzymes. Birds given injections of UV-inactivated RE viruses or reticuloendotheliosis virus-transformed, non-virus-producing tumor cells also exhibited a reduction in phosphoenolpyruvate carboxykinase activity.     

Inhibition of oncogenic K-ras signaling by aerosolized gene delivery in a mouse model of human lung cancer.

PURPOSE: Transfer of growth-suppressive genes to lung tumors has therapeutic potential, but effective delivery techniques have not been developed. Here, we investigated gene delivery to lung tumors by aerosolization of adenoviral vectors incorporated into calcium phosphate precipitates. EXPERIMENTAL DESIGN: To investigate the efficacy of this delivery method in normal and neoplastic lung, an adenoviral vector expressing beta-galactosidase was administered by jet nebulization to K-ras(LA1) mice, which develop lung adenocarcinomas through activation of a latent allele carrying mutant K-ras(G12D). Furthermore, we investigated whether aerosolized delivery of Ad-MKK4 (KR), an adenoviral vector expressing dominant-negative mutant mitogen-activated protein kinase kinase 4(MKK4), can block Ras-dependent signaling in K-ras(LA1) mice. RESULTS: After a single administration, beta-galactosidase was detected in lung tissue for up to 21 days, and expression was much greater in tumors than in normal lung tissue. MKK4 was activated in the lungs of K-ras(LA1) mice, and aerosolized treatment with Ad-MKK4 (KR) decreased c-Jun-NH(2)-terminal kinase but not extracellular signal- regulated kinase activity, providing evidence that MKK4 was selectively inhibited. CONCLUSIONS: These findings demonstrate a novel approach to targeting oncogenic pathways in lung tumors by aerosolized gene delivery.     

Characterisation of systemic dissemination of nonreplicating adenoviral vectors from tumours in local gene delivery

Systemic virus dissemination is a potential problem during local gene delivery in solid tumours. However, the kinetics and pathways of the dissemination have not been well characterised during the first 24 h after the infusion is started. To this end, we infused adenoviral vectors for luciferase or enhanced green fluorescence protein into three different tumour models in mice. During and/or after the infusion, we determined the amount of adenoviruses in the tumour, blood, and liver, and examined the transgene expression in the liver, lung, blood, and tumour. In addition, we intravenously injected tumour cells expressing luciferase and examined the biodistribution of these cells in the body. We observed transgene expression in the liver and tumour at 24 h after the infusion, but could not detect transgene expression in the blood and lung. The peak concentration of viral vectors in the plasma occurred during the intratumoral infusion. At 10 min after the infusion, few viral vectors remained in the blood and the ratio of copy numbers of adenoviruses between liver and tumour was > 2 in 80% and > or = 10 in 40% of the mice. Most tumour cells injected intravenously accumulated in the lung within the first 24 h. Taken together, these data indicated that systemic virus dissemination occurred mainly during the first 10 min after the intratumoral infusion was started, and that the dissemination was due to infusion-induced convective transport of viral vectors into leaky tumour microvessels.     

Targeting of suicide gene delivery in pancreatic cancer cells via FGF receptors

Pancreatic ductal adenocarcinomas (PDACs) overexpress various cell-surface tyrosine kinase receptors, including the type I high-affinity fibroblast growth factor receptor (FGFR-1). The purpose of this study was to determine whether FGFR-targeted gene therapy is feasible in this disorder. Accordingly, the effects of a conjugate consisting of fibroblast growth factor (FGF)-2 linked to a Fab' fragment against the adenovirus knob region were evaluated in human pancreatic cancer cell lines treated with an adenoviral vector containing the herpes simplex virus thymidine kinase (AdTK) gene. An adenoviral vector containing the firefly luciferase reporter gene (AdLuc) served to assess infection efficiency, and was initially tested in L6 rat myoblasts. In parental L6 cells that express exceedingly low levels of high-affinity FGFRs, transduction with AdLuc was enhanced 7- to 10-fold with the FGF2-Fab' conjugate, whereas in L6 cells transfected to express FGFR-1, it was enhanced 39- to 52-fold. The pancreatic cancer cell lines expressed variable levels of the four high-affinity FGF receptors, and exhibited 2- to 34-fold increases in gene transduction in the presence of the FGF2-Fab' conjugate. In the absence of FGF2-Fab' there was no correlation between surface binding of FGF2 and AdLuc transduction efficiency, whereas in the presence of FGF2-Fab', enhanced AdLuc transduction efficiency correlated with greater surface binding of FGF2. In the absence of AdTK, all the cell lines were insensitive to ganciclovir, whereas after AdTK transduction, only ASPC-1 and PANC-1 cells were resistant to ganciclovir even in the presence of FGF2-Fab'. Ganciclovir-mediated inhibition was dependent on the conjugate in CAPAN-1 and COLO-357 cells, but was independent of the conjugate in T3M4 and MIA-PaCa-2 cells. Real-time quantitative PCR of laser-captured cancer cells revealed high levels of various FGFR mRNA species in six of seven PDAC tumor samples. These findings indicate that transduction efficiency with FGF2-Fab' in pancreatic cancer cells is independent of native adenoviral transduction efficiency and is greatest in cells that exhibit concomitant expression of various high-affinity FGFRs. In view of the overexpression of high-affinity FGFRs in the cancer cells in PDAC, our findings also suggest that the combined use of AdTK, ganciclovir, and FGF2-Fab' may ultimately be a promising therapeutic approach in a subgroup of patients with PDAC.     

Inhibition of systemic TNF-alpha cytotoxicity in cancer patients by D-peptidoglycan

The current study was designed to investigate direct inhibitory effects of N-acetylglucosaminyl-muramyldipeptide (GMDP) over the cytotoxic nature of TNF-α. A lactate dehydrogenase (LDH) assay of the inhibition of TNF-α cytotoxicity was donein vitro on the following cell lines: A549 (human lung carcinoma cells), A431 (human breast cancer cells) and L929 (mouse breast cancer cells). In a double-blind placebo-controlled trial, cancer patients with an elevated activity of all five LDH isoensymes were randomized to receive either a GMDP solution or a placebo; 63 patients were evaluated every third day for the mean daily number of episodes of nausea or vomiting, changes in clinical status, cell blood count and blood chemistry. A 95% inhibition of LDH release was noticed on A549 cells. Other cell lines were less sensitive to GMDP, with an observed 72% dose-dependent reduction in LDH activity.In vivo, LDH activity was decreased by 41% (+/−4%) (mean +/−SD) in all 21 subjects who were given 0.5–1.0 mg of GMDP daily. A lowering of LDH activity by 73.4% (+/−4%) was observed in 23 patients who received GMDP at a dosage of 1.5 mg/kg daily. Correspondingly, a 10% (+/−2%) increase in LDH activity was noticed in 19 patients who were given a placebo (P<0.01). During the follow-up period, the overall clinical condition of all patients treated with GMDP was improved. No side effects were observed. In nine patients who experienced nausea from tumor toxicity before treatment, the symptom subsided. In parallel, an extremely beneficial effect on lipids metabolism was noticed in all patients with elevated cholesterol and trigliceride levels. A dietary supplementation of GMDP has been shown to reduce systemic TNF-α cytotoxicity during tumor shock.     

Inhibition of melanoma by ultrasound-microbubble-aided drug delivery suggests membrane permeabilization

Ultrasound exposure-induced cavitation has been shown to accentuate cell membrane permeability, thus promoting effective drug delivery into cells, a technique that can be enhanced in the presence of microbubbles (MB). Here we applied this method as a treatment for malignant melanoma of the eyelid. The incidence of malignant melanoma in ophthalmology is relatively high, but its treatment is cosmetically difficult. A greater in vitro growth suppression of B-16 melanoma cells was achieved using ultrasound and MB in combination with the anticancer drug bleomycin than when a more concentrated dose of bleomycin alone was applied to the cell culture. Moreover, this effect was enhanced in an in vivo tumor model created by injecting B-16 melanoma cells into the lower eyelids of SCID mice. The antitumor effect of bleomycin was observed at a lower dose (0.5 mg/ ml) when the treatment was used in conjunction with ultrasound. The effect was further enhanced when MB were included, with tumor shrinkage occurring at bleomycin levels of 0.06 mg/ml. These results show that ultrasound and MB promote efficient bleomycin uptake by cells, and that the technique is a potentially useful drug delivery method.     

Apoptin对肝癌细胞的体内、外抑制效应

目的: 探讨Apoptin对人肝癌细胞株HepG2及C57BL/6小鼠H22移植瘤的抑制作用。方法：应用脂质体转染法将重组质粒pVAX1Apoptin转染HepG2细胞,应用Western blotting检测Apoptin蛋白在转染后HepG2细胞中的表达,应用MTT检测Apoptin对HepG2细胞生长的抑制作用,通过AO/EB染色法检测pVAX1Apoptin致肿瘤细胞凋亡作用。建立C57BL/6小鼠H22荷瘤模型,瘤内注射pVAX1Apoptin,观察pVAX1Apoptin对体内肿瘤的抑制作用。结果： Apoptin基因可在HepG2细胞中有效表达,pVAX1Apoptin能够诱导HepG2细胞凋亡,并显著地抑制其生长,48 h抑制率为69.28%。pVAX1Apoptin瘤内注射能够有效抑制移植肿瘤的生长,抑制率为46.71%;治疗后39 d小鼠生存率为40%,显著高于对照组(P<005)。结论： Apoptin转染可抑制HepG2细胞的生长,重组质粒pVAX1Apoptin瘤内注射对移植肿瘤有显著的抑制作用。     

Ａｄ-ＩＮＧ４抑制裸鼠人肝癌移植瘤生长的体内实验研究

目的　研究携带ＩＮＧ４基因的重组腺病毒（Ａｄ-ＩＮＧ４）对人肝癌细胞株ＳＭＭＣ-７７２１移植瘤生长的抑制作用及其潜在的分子机制。方法　将扩增的Ａｄ-ＩＮＧ４感染ＳＭＭＣ-７７２１细胞,Ｗｅｓｔｅｒｎｂｌｏｔ法检测Ａｄ-ＩＮＧ４在ＳＭＭＣ-７７２１细胞中的转录。用ＳＭＭＣ-７７２１细胞建立裸鼠人肝癌移植瘤模型,予Ａｄ-ＩＮＧ４（１×１０^９ｐｆｕ／ｍｌ）５０μｌ对移植瘤瘤体注射治疗,观察肿瘤生长变化;３周后处死裸鼠,摘除瘤体,称瘤重;免疫组化法检测ｐ２１、ＣＯＸ-２、Ｆａｓ、Ｂｃｌ-２、Ｂａx、Ｃａｓｐａｓｅ-３、ＶＥＧＦ、ＣＤ３４等因子的表达。结果　Ａｄ-ＩＮＧ４在ＳＭＭＣ-７７２１细胞中成功表达;Ａｄ-ＩＮＧ４对裸鼠人肝癌移植瘤有明显的生长抑制作用,Ａｄ-ＩＮＧ４组瘤体显著减小（Ｐ＜０.０１）,抑瘤率达４１.６４％;免疫组化检测显示,Ａｄ-ＩＮＧ４抑癌的分子机制可能与上调ｐ２１、Ｆａｓ、Ｂａｘ和Ｃａｓｐａｓｅ-３的表达及下调ＣＯＸ-２、Ｂｃｌ-２、ＶＥＧＦ和ＣＤ３４的表达有关。结论　Ａｄ-ＩＮＧ４能有效抑制ＳＭＭＣ-７７２１裸鼠人肝癌移植瘤的生长,其机制可能通过抑制肿瘤细胞生长、血管形成和激活细胞凋亡等多个途径共同发挥抑癌效应。     

Inhibition of p53 increases chemosensitivity to 5-FU in nutrient-deprived hepatocarcinoma cells by suppressing autophagy

Activation of p53 can induce apoptosis, cell cycle arrest, and cell senescence, although some evidence has suggested that p53 could promote cell survival. However, whether p53 plays a positive role in cancer cell survival to chemotherapy remains unknown. In this study, we show that inhibition of p53 enhanced apoptosis and increased chemosensitivity to 5-fluorouracil (5-FU) in nutrient-deprived hepatocarcinoma cells (HCC). Meanwhile, nutrient-deprivation-induced autophagy was inhibited by pifithrin-α or small interfering RNA targeting p53. The expression of p53 was not increased when HCC were incubated under nutrient-deprived conditions. This indicates that the basal level of p53 is important to autophagy activation in nutrient-deprived HCC cells. Furthermore, combining p53 inhibition and nutrient deprivation or 5-FU treatment resulted in a marked increase in reactive oxygen species generation and mitochondrial damage. Antioxidants reduced nutrient deprivation or 5-FU-induced cell death of HCC after p53 inhibition. Our results suggest that p53 contributes to cell survival and chemoresistance in HCC under nutrient-deprived conditions by modulating autophagy activation.