Utilizing tumor hypoxia to enhance oncolytic viral therapy in colorectal metastases

OBJECTIVE: To determine the effects of hypoxia-induced ribonucleotide reductase (RR) production on herpes oncolytic viral therapy. SUMMARY BACKGROUND DATA: Hypoxia is a common tumor condition correlated with therapeutic resistance and metastases. Attenuated viruses offer a unique cancer treatment by specifically infecting and lysing tumor cells. G207 is an oncolytic herpes virus deficient in RR, a rate-limiting enzyme for viral replication. METHODS: A multimerized hypoxia-responsive enhancer was constructed (10xHRE) and functionally tested by luciferase assay. 10xHRE was cloned upstream of UL39, the gene encoding the large subunit of RR (10xHRE-UL39). CT26 murine colorectal cancer cells were transfected with 10xHRE-UL39, incubated in hypoxia (1% O2) or normoxia (21% O2), and infected with G207 for cytotoxicity assays. CT26 liver metastases, with or without 10xHRE-UL39, were created in syngeneic Balb/C mice (n = 40). Livers were treated with G207 or saline. Tumors were assessed and stained immunohistochemically for G207. RESULTS: 10xHRE increased luciferase expression 33-fold in hypoxia versus controls (P < 0.001). In normoxia, 10xHRE-UL39 transfection did not improve G207 cytotoxicity. In hypoxia, G207 cytotoxicity increased 87% with 10xHRE-UL39 transfection versus nontransfected cells (P < 0.001). CT26 were resistant to G207 alone. Combining 10xHRE-UL39 with G207 resulted in a 66% decrease in tumor weights (P < 0.0001) and a 65% reduction in tumor nodules (P < 0.0001) versus G207 monotherapy. 10xHRE-UL39-transfected tumors demonstrated greater viral staining. CONCLUSIONS: Hypoxia-driven RR production significantly enhances viral cytotoxicity in vitro and reduces tumor burden in vivo. G207 combined with RR under hypoxic control is a promising treatment for colorectal cancer, which would otherwise be resistant to oncolytic herpes virus alone.     

Utilizing alpha-fetoprotein expression to enhance oncolytic viral therapy in hepatocellular carcinoma

OBJECTIVE: To determine whether alpha-fetoprotein (AFP)-regulated ribonucleotide reductase (RR) production would promote more vigorous and specific viral killing in AFP-expressing hepatocellular carcinoma (HCC). BACKGROUND: AFP is expressed in over 70% of primary HCC but not in normal adult liver. AFP production by HCC can be exploited to target viral killing of tumor cells. G207 is an oncolytic herpes virus lacking UL39, the gene encoding RR. RR is an enzyme required for viral DNA synthesis and cytotoxicity. METHODS: Enzyme-linked immunosorbent assay (ELISA) was performed for AFP levels on Hep3B and PLC5 human HCC cells. An AFP-albumin enhancer-promoter complex (AFP-alb) was constructed in a luciferase vector to assess function. AFP-alb was cloned upstream of UL39 (AFP-alb/UL39) and transfected into HCC cells for G207 cytotoxicity assays. Viral plaque forming assays evaluated G207 replication. Hep3B flank tumors, with and without AFP-alb/UL39 transfection, were established in athymic mice (n = 28) and treated with G207. RESULTS: Hep3B had 5-fold higher AFP levels than PLC5 (P < 0.00001). AFP-alb increased luciferase expression 72-fold in Hep3B (P < 0.001) and 3-fold in PLC5 (P < 0.001). AFP-alb/UL39 transfection increased G207 cytotoxicity 93% in Hep3B (P < 0.0005), with no significant increase in PLC5. Peak viral titers were 46-fold higher in Hep3B transfected with AFP-alb/UL39 versus mock-transfected cells (P < 0.01), with no significant change in PLC5. Flanks tumors transfected with AFP-alb/UL39 and treated with G207 demonstrated a 76% volume reduction versus mock-transfected tumors infected with G207 (P < 0.0001). CONCLUSIONS: AFP-driven RR production by hepatoma cells significantly enhances herpes viral cytotoxicity and specificity in vitro and reduces tumor burden in vivo.     

Ionizing radiation potentiates the antitumor efficacy of oncolytic herpes simplex virus G207 by upregulating ribonucleotide reductase

BACKGROUND: Replication-competent herpes simplex virus-1 (HSV-1) mutants have an oncolytic effect on human and animal cancers. The aim of this study was to determine whether G207, an HSV-1 mutant, can be combined with ionizing radiation (IR) to increase antitumor activity while decreasing treatment-associated toxicity. METHODS: This study was performed by using G207, a replication-competent HSV-1 mutant deficient in viral ribonucleotide reductase (RR) and the gamma(1)34.5 neurovirulence protein. The antitumor activity of G207 or IR was tested against HCT-8 human colorectal cancer cells in vitro and in an in vivo mouse subcutaneous tumor model. RESULTS: We demonstrated that G207 has significant oncolytic effect on HCT-8 cells in vitro in a cytotoxicity assay and in vivo in a mouse flank tumor model and that these effects are improved with low-dose IR. We further illustrated that the increased tumoricidal effect is dependent on the up-regulation of cellular RR by IR measured by a functional bioassay for RR activity. Chemical inhibition of RR by hydroxyurea abrogates the enhanced effect. In contrast to G207, R3616, the parent virus of G207 that expresses functional RR, does not exhibit enhanced oncolysis when combined with IR. CONCLUSIONS: These data encourage clinical investigation of combination radiation therapy and HSV oncolytic therapy.     

Oncolytic herpes viral therapy is effective in the treatment of hepatocellular carcinoma cell lines

The rising incidence of hepatocellular carcinoma (HCC) in western countries, along with the poor prognosis offered by present-day treatment modalities, makes novel therapies for this disease necessary. Oncolytic herpes simplex viruses (HSV) are replication-competent viruses that are highly effective in the treatment of a wide variety of experimental models of human malignancies. This study seeks to investigate the effectiveness of oncolytic herpes viruses in the treatment of primary HCC cell lines. Sixteen commercially available human HCC cell lines were studied. G207 is an attenuated, replication-competent, oncolytic HSV engineered to selectively replicate within cancer cells. Cell lines were tested for viral sensitivity to G207 and their ability to support viral replication using standard cytotoxicity and viral replication assays. Eleven of 16 cell lines were moderately to highly sensitive to G207 viral oncolysis. HCC cell lines additionally demonstrated the ability to support viral replication in vitro with as high as 800-fold amplification of the administered viral dose observed. G207 is cytotoxic to, and efficiently replicates within, HCC cell lines in vitro. From these data, we suggest that oncolytic HSV therapy may have a role in the treatment of HCC, and in vivo studies are warranted. Presented in part at the 2005 American Hepato-Pancreato-Biliary Association Congress, Hollywood, Florida, April 14–17, 2005. Supported by grants R01CA75461 and R01CA72632 from the National Institutes of Health, and by grant MBC-99366 from the American Cancer Society (Yuman Fong).     

Effective treatment of pancreatic tumors with two multimutated herpes simplex oncolytic viruses

Pancreatic cancer is an aggressive, rapidly fatal disease against which current nonsurgical therapy has minimal impact. This study evaluates the efficacy of two novel, replication-competent, multimutated herpes viruses (G207 and NV1020) in an experimental model of pancreatic cancer. Four human pancreatic carcinoma cell lines were exposed to G207 or NV1020, and cell survival and viral progeny production were determined. Flank tumors in athymic mice were subjected to single or multiple injections of 1 X 10⁷ G207 or NV1020, and tumor volume was evaluated over time. For all of the cell lines, G207 and NV1020 produced infection, viral replication, and cell lysis (P <0.05). NV1020 resulted in a higher production of viral progeny compared to G207. The efficacy of viral tumor cell kill was greatest in those cells with the shortest in vitro doubling time. For flank tumors derived from hs766t, single or multiple injections of both viruses were equally effective and significantly reduced flank tumor burden (P <0.05). Complete hs766t flank tumor eradication was achieved in 25% (5 of 20) of animals treated with G207 and 40% (8 of 20) of animals treated with NV1020. In vivo efficacy correlated with in vivo tumor doubling time. There were no adverse effects related to viral administration observed in any animal. NV1020 and G2O7 effectively infect and kill human pancreatic cancer cells in vitro and in vivo. Given the lack of effective nonoperative treatments for pancreatic cancer, oncolytic herpes viruses should be considered for clinical evaluation. Presented in part at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 21–24, 2000.     

G207, modified herpes simplex virus type 1, kills human pancreatic cancer cells in vitro

Pancreatic cancer is often fetal, and farther effective therapeutic options are needed. This study was designed to assess whether the replication-restricted herpes simplex virus, G207, was effective in killing human pancreatic cancer cells in vitro. G207, a multimutated strain of herpes simplex virus type 1 carrying lacZ reporter gene, is capable of efficient cytolytic growth in many dividing cells, including certain tumor cells, but not in nondividing cells. Three human pancreatic cell lines, AsPC-1, MIA PaCa-2, and BxPC-3, were infected with G207 at different multiplicities of infection. After 24 hours, expression of the lacZ reporter gene was tested using a histochemical X-gal assay. In addition, cell lines were infected with G207 for 24 to 48 hours; then the virus obtained from cell pellets and media supernatant was used to infect Vero cells to obtain G207 titers by plaque assay. To assess whether increasing viral immediate early gene expression would improve cytolysis and virus production, similar experiments were performed with the addition of 0.5 mmol/L of hexamethylene bisacetamide (HMBA) 1 hour after viral infection. Finally, MTS cell viability assays were performed to measure viable cells at 24 to 96 hours post infection. The X-gal assay data revealed a viral dose-dependent β-galactosidase expression, indicating G207 infectivity and expression of the lacZ reporter gene. Plaque assays demonstrated a viral dose-dependent increase in plaque formation, indicating viral production from all three cell lines. In addition, HMBA data indicated a modest increase in viral production. The MTS assay data indicated a dose-dependent cytotoxicity for G207 in the cell lines tested. G207 infects, replicates in, and is cytotoxic to the above-listed human pancreatic cell lines in vitro and warrants therapeutic evaluation in models of pancreatic cancer. Supported by the Wilmot Cancer Research Fellowship Program funded by the James P. Wilmot Foundation. Presented at the Thirty-Ninth Annual Meeting of The Society for Surgery of the Alimentary Tract, New Orleans, La., May 17–20,1998.     

Employing Tumor Hypoxia for Oncolytic Therapy in Breast Cancer

Hypoxia is a common tumor condition associated with metastases, therapeutic resistance, and poor patient survival. Forty percent of breast cancers are hypoxic, with a median oxygen concentration of 3.9%, and a third of tumors have regions less than 0.3%. Normal breast tissue is reported to have oxygen concentrations greater than 9%. This tumor hypoxia in breast cancer confers resistance to conventional radiation therapy and chemotherapy, as well as making estrogen-receptor-positive tumors less sensitive to hormonal therapy. Novel treatment modalities are needed to target hypoxic tumor cells. Lower tumor oxygen levels compared with surrounding normal tissues may be utilized to target and enhance herpes oncolytic viral therapy in breast cancer. Attenuated oncolytic herpes simplex viruses offer a unique cancer treatment by specifically infecting, replicating within, and lysing tumor cells. They carry genetically engineered mutations to reduce their virulence and attenuate their ability to infect normal tissues. Studies have shown the safety and efficacy of oncolytic herpes simplex viruses in treating breast cancer both in humans and in preclinical models. The placement of essential viral genes under the control of a hypoxia-responsive enhancer, which is upregulated selectively in hypoxic tissue, represents a promising strategy to target oncolytic viruses precisely to hypoxic cancer cells. In this review we describe strategies to harness hypoxia as a trigger for oncolytic viral gene expression in breast cancer, thereby increasing the specificity of viral infection, replication, and cytotoxicity to hypoxic areas of tumor. Such a targeted approach will increase efficacy in the therapy of hypoxic tumors while achieving a reduction in total dose of viral therapy.Supported in part by AACR-Astra Zeneca Cancer Research and Prevention Foundation Fellowship (P.S.A), grants RO1 CA 75416 and RO1 CA/DK80982 (Y.F.) from the National Institutes of Health, grant MBC-99366 (Y.F.) from the American Cancer Society, grant BC024118 from the US Army (Y.F.), grant IMG0402501 from the Susan G. Komen Breast Cancer Foundation (Y.F. and P.S.A.) and grant 032047 from Flight Attendant Medical Research Institute (Y.F. and P.S.A.)     

缺氧下调结肠癌细胞株CDX2表达的研究

目的探讨缺氧诱导因子1α(HIF-1α)和基因系尾型同源盒基因2(CDX2)在人结肠癌细胞株SW480和LS174T不同缺氧时间的表达及其可能的作用机制。方法(1)MTT方法检测在不同CoCl2浓度(100,150,200μmol/L)下和不同时点(24,36,48 h)时对SW480和LS174T细胞活力以及增殖的影响,筛选适宜的CoCl2作用浓度。(2)在细胞化学缺氧培养相应时段,采用半定量RT-PCR技术检测HIF-1α,Snail和CDX2的mRNA的表达变化;同时采用Western blotting技术检测CDX2的蛋白表达。结果结肠癌细胞株在不同浓度CoCl2环境下随缺氧时间的延长,细胞活力明显受到抑制。在低浓度CoCl2(100μmol/L)干预下,随着缺氧时间的延长,HIF-1α和Snail mRNA表达逐渐上升,缺氧24 h时达到高峰,CDX2 mRNA及蛋白表达水平逐渐下降。结论缺氧诱导HIF-1α过表达可通过下调CDX2而加速结直肠癌的进展。     

表没食子儿茶素没食子酸酯对结肠癌细胞株HCT-8和HT29的抑制作用及影响机制

目的探讨绿茶提取物表没食子儿茶素没食子酸酯（EGCG）对结肠癌细胞株HCT－8细胞和HT29细胞增殖的抑制作用,研究其对HESl与JAGl基因表达的影响。方法体外培养HCT-8细胞和HT29细胞,采用不同浓度的EGCG（10、20、35mg／L）对其进行干预,MTT法检测EGCG对HCT-8细胞和HT29细胞增殖的抑制作用：用流式细胞仪检测EGCG对HCT-8细胞和HT29细胞细胞凋亡和细胞周期的影响。实时荧光定量PCR检测EGCG干预后的HCT-8细胞和HT29细胞的HESl与JAGl基因的表达情况。结果EGCG对HCT-8细胞和HT29细胞增殖及凋亡均有影响,3个EGCG浓度对HCT-8增殖抑制率分别为（28．894±5．076）％,（34．903±1．794）％和（39．028±0．105）％;对HT29的增殖抑制率分别为（14．682±4．244）％、（22．429±3．847）％和（29．840±5．076）％。EGCG能将HCT-8细胞阻滞在G／M期,阻碍其向M期转换,将HT29细胞阻滞在S期,阻碍其向G2期转换,抑制其细胞增殖。EGCG可下调两株细胞HESl的基因表达,但差异均无统计学意义（P〉0．05）：EGCG能上调两株细胞JAGl的基因表达,但只有HCT．8细胞的基因表达差异有统计学意义（O．201±0．018比0．440±0．077．P=0．029）。结论EGCG对体外培养的HCT-8细胞和HT29细胞的增殖有明显抑制作用．且能诱导细胞凋亡和影响细胞周期。其作用机制可能与上调JAGl的基因表达有关。     

5-Fluorouracil and gemcitabine potentiate the efficacy of oncolytic herpes viral gene therapy in the treatment of pancreatic cancer

Oncolytic herpes viruses are attenuated, replication-competent viruses that selectively infect, replicate within, and lyse cancer cells and are highly efficacious in the treatment of a wide variety of experimental cancers. The current study seeks to define the pharmacologic interactions between chemotherapeutic drugs and the oncolytic herpes viral strain NV1066 in the treatment of pancreatic cancer cell lines. The human pancreatic cancer cell lines Hs 700T, PANC-1, and MIA P_aC_a-2 were treated in vitro with NV1066 at multiplicities of infection (MOI; ratio of the number of viral particles per tumor cell) ranging from 0.01 to 1.0 with or without 5-fluorouracil (5-FU) or gemcitabine. Synergistic efficacy was determined by the isobologram and combination-index methods of Chou and Talalay. Viral replication was measured using a standard plaque assay. Six days after combination therapy, 76% of Hs 700T cells were killed compared with 43% with NV1066 infection alone (MOI = 0.1) or 0% with 5-FU alone (2 βmol/L) (P < .01). Isobologram and combination-index analyses confirmed a strongly synergistic pharmacologic interaction between the agents at all viral and drug combinations tested (LD5 to LD95) in the three cell lines. Dose reductions up to 6- and 78-fold may be achieved with combination therapy for NV1066 and 5-FU, respectively, without compromising cell kill. 5-FU increased viral replication up to 19-fold compared with cells treated with virus alone. Similar results were observed by combining gemcitabine and NV1066. We have demonstrated that 5-FU and gemcitabine potentiate oncolytic herpes viral replication and cytotoxicity across a range of clinically achievable doses in the treatment of human pancreatic cancer cell lines. The potential clinical implications of this synergistic interaction include improvements in efficacy, treatment-associated toxicity, tolerability of therapeutic regimens, and quality of life. These data provide the cellular basis for the clinical investigation of combined oncolytic herpes virus therapy and chemotherapy in the treatment of pancreatic cancer. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 141-18, 2005 (oral presentation). Supported in part by training grant T 32 CA09501 (D.P.E. and K.J.H.), AACR-AstraZeneca Cancer Research and Prevention fellowship (P.S.A), grants RO1 CA 76416 and RO1 CA/DK80982 (Y.F.) from the National Institutes of Health, grant BC024118 from the U.S. Army (Y.F.), grant IMG0402501 from the Susan G. Komen Foundation (Y.F.), and grant 032047 from Flight Attendant Medical Research Institute (Y.F.).     

苯乙酸对人结直肠癌细胞HCT-8的G1细胞周期阻滞及增殖抑制作用

摘要：目的 探讨诱导分化剂苯乙酸（PA）对人结直肠癌细胞系HCT 8细胞周期及增殖的影响。 方法 应用MTT比色法，以1.0，2.0，3.0，4.0，5.0 mmol/L的PA作用于体外培养的HCT 8细胞，分别于24，48，72h后对细胞增殖进行检测；流式细胞术分析细胞周期。结果 随着PA浓度的增加（1～5 mmol/L）或药物作用时间的延长（24～72h），肿瘤细胞生长抑制率明显增加。PA1~5mmol/L作用24h细胞生长抑制率为5.1%-24.3%，48h为16.7%-72.3%，72h为30.2%-93.4%。PA作用细胞72h后，G0/G1期比例显著下降，S期比例相对升高，组间差异显著（P＜0.05）。结论 PA在诱导分化结直肠癌HCT 8细胞过程中，可诱导G1细胞周期阻滞，抑制细胞增殖。     

Ligand-dependent activation of the epidermal growth factor receptor by secondary bile acids in polarizing colon cancer cells

BACKGROUND: Secondary bile acids such as deoxycholic acid (DCA) are known to promote colorectal cancer (CRC). Increasing evidence suggests that DCA-induced signaling is mediated by activation of the epidermal growth factor receptor (EGFR). We have shown that activation of the EGFR induces up-regulation of cyclooxygenase 2, basolateral release of prostaglandins (PGs), and mitogenesis in a polarizing human colon cancer cell line, HCA-7. The purpose of this study was to determine the mechanism by which DCA activates EGFR in human polarizing CRC cell lines HCA-7 and HCT-8. METHODS: A primary, non-tumor-promoting bile acid (cholic acid [CA]) and a secondary, tumor-promoting bile acid, DCA, were added to the apical and basolateral compartment of polarized HCA-7 and HCT-8 cells. These cells were pretreated with monoclonal antibody 528, a monoclonal antibody that inhibits ligand binding to EGFR, or with WAY-022, a selective inhibitor of tumor necrosis factor-alpha converting enzyme/a disintegrin and metalloprotease-17 (TACE/ADAM-17), which cleaves amphiregulin (AR) to its mature, soluble form from the basolateral cell membrane. AR levels were measured in the apical and basolateral medium and cell lysates by radioimmunoassay. PGs were measured in the apical and basolateral medium by gas chromatography/mass spectrometry. RESULTS: Basolateral delivery of DCA, but not CA, preferentially stimulated release of AR into the basolateral medium compared with cell lysates of polarized HCA-7 and HCT-8 cells. Basolateral delivery of DCA resulted in increased basolateral PGE2 levels (P < .05), and this effect was attenuated by pretreatment with monoclonal antibody 528 (P < .05). Inhibiting cell surface cleavage of AR with WAY-022 before DCA treatment reduced AR (P < .05) and PGE2 (P < .05) levels in the basolateral medium. CONCLUSION: DCA, but not CA, results in compartment-specific, ligand-dependent activation of EGFR and subsequent increased basolateral PGE2 levels. The mechanism of DCA-induced EGFR activation is ligand-dependent and is controlled, at least in part, at the level of AR release from the basolateral cell membrane.     

尿核苷检测在结直肠癌诊断与手术治疗监测中的应用

目的探讨尿核苷检测对结直肠癌的诊断价值及在手术治疗监测中的应用。方法采用反相高效液相色谱法检测经结肠镜与活检病理证实的52例结直肠癌患者术前1天与术后第8天尿中14种正常与修饰核苷水平,同时以62例健康人作为对照组,并与传统肿瘤标记物癌胚抗原(CEA),CA199,CA125,甲胎蛋白(AFP)相比较,探讨尿核苷与结直肠癌临床病理特征的关系。结果结直肠癌组14种核苷中假尿嘧啶核苷(Pseu),腺嘌呤核苷(A),胞嘧啶核苷(C),1甲基腺苷(m1A),1甲基次黄嘌呤核苷(m1I),3甲基尿苷+5甲基尿苷(mU),2,2二甲基鸟苷(m22G),次黄嘌呤核苷(I),1甲基鸟苷(m1G),N4乙酰胞苷(ac4C),6甲基腺苷(m6A)等11种核苷水平显著升高,与正常对照组相比差异具有统计学意义(P<0.05);通过主成分分析,76.9%(40/52)的结直肠癌患者被正确识别,敏感性与传统标记物CEA(38.5%),CA199(40.4%),CA125(15.4%),AFP(17.3%)相比差异有统计学意义(均P<0.01);Pseu与m1G的受试者操作特征曲线下面积分别达到0.896与0.816;对8种核苷(Pseu,m1A,m1I,m22G,I,m1G,ac4C,m6A)进行逐步判别分析,发现Pseu、m1G在判别分析中有统计学意义,建立判别函数Y正常人=-3.009+0.0272×Pseu+4.918×m1G,Y结直肠癌=-8.057+0.0667×Pseu+8.258×m1G;40例结直肠癌患者的Pseu,C,U(尿嘧啶核苷)     

AdKDR-CDglyTK系统对结直肠癌细胞及血管内皮细胞的靶向杀伤作用

目的研究腺病毒介导的血管内皮细胞生长因子受体(KDR)启动子驱动CD/TK双自杀基因系统对血管内皮细胞及结直肠癌肿瘤细胞的选择性杀伤作用。方法质粒pAdEasy-KDR-CDglyTK和pAdEasy-CMV-CDglyTK在293细胞中包装、扩增后,体外感染表达KDR的ECV304、SW620细胞株和不表达KDR的LS174T细胞株,观察其感染效率并以RT-PCR方法检测转基因细胞CDglyTK的表达,然后给予不同浓度的前药5-氟胞嘧啶(5-FC)及更昔洛韦(GCV)处理,观察该体系对不同细胞株的杀伤效应及其旁观者效应。结果两种病毒滴度均为2.0×1012pfu/ml。两种重组体对各细胞株的感染率相似,其感染率随腺病毒滴度的增高而递增。RT-PCR方法检测发现:除感染AdKDR-CDglyTK的LS174T细胞外,感染AdCMV-CDglyTK的所有细胞及感染AdKDR-CDglyTK的其他两种细胞均有目的基因CDglyTK的表达。该体系治疗结果提示:(1)感染AdCMV-CDglyTK的所有细胞株和感染AdKDR-CDglyTK的ECV304、SW620细胞对前药具有较高的敏感性,且其敏感性差异无显著性意义(均P>0.05),与前两者相比感染AdKDR-CDglyTK的LS174T细胞对前药不敏感(均P<0.001);(2)双自杀基因的疗效优于任一单自杀基因的疗效(均P<0.001);(3)该体系旁观者效应明显。结论KDR基因启动子可调控双自杀基因系统选择性杀伤表达KDR的血管     

腺病毒驱动KDR启动子介导CD/TK融合基因系统对血管内皮细胞的靶向杀伤作用

目的　探讨腺病毒介导KDR启动子驱动的融合基因体系,对人脐血管内皮细胞ECV30 4的选择性杀伤作用。方法　将质粒pAdEasy -KDR- CDglyTK在2 93细胞内包装、扩增后,体外感染表达KDR的ECV30 4细胞株和不表达KDR的LS174T细胞株,并给予不同浓度的前药5 - 氟胞嘧啶(5 -fuorocytosine ,5 -FC)和/或丙氧鸟苷(ganciclovir,GCV) ,观察该体系对不同细胞株的杀伤效应及其旁观者效应;并以流式细胞仪检测细胞周期的变化,电镜观察细胞的病变。结果　所得病毒对两种细胞细胞的感染率相似,其感染率随腺病毒滴度的递增而增加;表达KDR的ECV30 4细胞对前药的具有较高的敏感性,不表达KDR的LS174T细胞对前药不敏感(P均<0 . 0 1) ;融合基因的疗效优于任一单自杀基因(P均<0 . 0 1) ;且观察到该体系明显的旁观者效应。流式细胞术检测治疗后ECV30 4细胞G1期比率增多及S期细胞减少(P均<0 . 0 1) ,同时,电镜下可见ECV30 4有凋亡和坏死改变。结论　KDR基因启动子可调控融合基因体系选择性杀伤人血管内皮细胞。     

Cortactin表达与结肠直肠癌肿瘤出芽的相关研究

目的: 分析皮层蛋白Cortactin在肿瘤组织的表达水平和肿瘤出芽程度与结肠直肠癌特征的相关关系。方法: 检测97例结肠直肠癌病人癌组织Cortactin的表达水平和肿瘤出芽程度,分析其与病人临床特征的相关性。结果: Cortactin表达水平与结肠直肠癌病人T分期（P=0.017）和N分期（P<0.001）显著相关。结肠直肠癌Cortactin表达水平较高的病人年龄较小（P=0.043）。肿瘤出芽程度与病人T分期（P=0.031）、血浆CEA水平（P=0.038）以及结肠直肠癌高危因素（P=0.008）显著相关。Cortactin表达与结肠直肠癌肿瘤出芽程度显著相关（P=0.011）。结论: Cortactin表达水平与结肠直肠癌出芽显著相关,提示Cortactin可能促进结肠直肠癌细胞出芽、恶性进展和预后不良。