中药制剂预防放射性直肠炎37例临床观察

目的 研究野生型p53基因转染卵巢癌SKOV－3细胞对放疗敏感性的影响。方法 用脂质体介导的转染技术，将人野生型p53 cDNA的真核表达重组质粒分别导入受不同剂量放射照射的SKOV－3培养细胞中，观察p53不同状态下对肿瘤细胞放疗敏感性的差异。结果 SKOV－3、SKOV－3－vect及SKOV－3－p53经2Gy照射后，其集落形成数分别下降了18．6％、22．9％及44．5％；经4Gy照射后，其集落形成数分别下降了63．6％、64．9％及88．9％。转染p53基因后，肿瘤细胞S期和G2／M期的比例下降，G1／G0期的比例增加，p53基因的转染使卵巢癌细胞发生G1期阻滞。结论 外源性野生型p53基因的转染，增加了卵巢癌SKOV－3细胞对放疗的敏感性。     

p53腺病毒重组体转染对p53缺失肿瘤细胞辐射敏感性的影响

目的观察p53腺病毒重组体（AdCMV-p53）转染对p53缺失肿瘤细胞辐射敏感性的影响。方法用腺病毒重组体（AdCMV—p53／GFP）转染经0、0．25、0．5、1．0、1．5、2．0Gyγ射线辐射的H1299（nullp53）和PC-3（nullp53）细胞，用流式细胞分析法检测外源性p53表达，用克隆形成法检测肿瘤细胞增殖能力。结果辐射联合AdCMV-p53转染组p53阳性细胞所占比例均明显高于单纯辐射组、单纯AdCMV—p53转染组和辐射联合AdCMV—GFP转染组同种细胞p53阳性率（P〈0．05）；AdCMV—p53转染不仅明显提高肿瘤细胞辐射敏感性，而且与肿瘤细胞组织来源有关。结论p53腺病毒重组体转染对p53基因缺失肿瘤细胞低剂量辐射敏感性的增强作用与肿瘤细胞来源的组织器官和细胞类型有关。     

电离辐射调控脂质体介导的p16基因在HeLa细胞中的表达

目的探讨不同剂量γ射线照射后诱导脂质体介导的p16基因在HeLa细胞中的表达及抗癌作用。方法用脂质体Lipofectamin介导重组质粒Egr-p16转染人HeLa细胞，采用RT-PCR的方法检测了。Coγ射线照射转染后的人HeLa细胞剂量效应和时程变化，用细胞计数检测细胞增殖的变化，用流式细胞术检测细胞周期的变化。结果研究证实0．5～8Gv照射后p16的转录水平高于对照，在2～4Gy照射后达到峰值，2Gy照射后2—24h高于对照组，在照射后4h达到峰值，然后逐渐下降。细胞生长曲线显示体外稳定转染联合。Coγ射线照射对HeLa细胞的增殖具有明显的抑制作用。细胞周期变化显示转染后的HeLa细胞经过照射后G0／G1期比例呈现剂量依赖性的下降，而S期则出现剂量依赖性的增加，出现明显的S期阻滞，G2／M期在2Gy出现明显的阻滞，在5和10Gy时逐渐下降，但是仍然高于对照组。结论^60Coγ射线可诱导转染的HeLa细胞p16转录水平的增强，同时在细胞增殖上出现明显的变化。     

pEgr-hPTEN稳定转染联合辐射诱导人胶质瘤SHG-44细胞凋亡及Bcl-2表达下调

目的 探讨辐射诱导表达载体pEgr-hPTEN体外稳定转染人胶质瘤SHG-44细胞后联合X射线照射，诱导细胞凋亡的作用及凋亡相关蛋白Bcl-2表达的变化。方法 以脂质体介导携有外源野生型PTEN基因的辐射诱导表达载体pEgr-hPTEN，体外转染SHG-44细胞，筛选稳定转染的细胞克隆并扩增培养；应用电子显微镜、流式细胞仪等方法，检测稳定转染联合X射线照射对胶质瘤细胞超微结构、细胞凋亡及Bcl-2蛋白表达等特性的影响。结果 稳定转染细胞超微结构有明显的退行性改变，可见核内染色质趋边的类似早期凋亡的改变；稳定转染联合X射线照射可诱导肿瘤细胞凋亡，5Gy以内随吸收剂量的增加，早期凋亡细胞百分数明显增加，稳定转染不同剂量照射组早期凋亡细胞百分数分别为稳定转染0Gy假照组的1．5—2．3倍、为未转染照射组的1．9—4．4倍、为未转染0Gy假照组的3．4—5．1倍；同时稳定转染细胞Bcl-2蛋白表达则呈剂量依赖性下降。结论 体外PTEN基因转染联合X射线照射可诱导肿瘤细胞凋亡明显增多，Bcl-2蛋白表达下调，具有显著的肿瘤抑制作用。     

辐射联合外源性野生型p53基因对不同p53状态的黑色素瘤细胞系的生物学效应

目的研究辐射结合腺病毒（Ad CMV）载体介导的p53基因转导对不同p53状态的人黑色素瘤细胞系基因转移效率、凋亡和辐射敏感性的影响。方法用复制缺陷的重组腺病毒载体（AdCMV-p53）介导入p53基因转导1Gy X射线预照射的黑色素瘤细胞系A375（wt p53）和WM983a（mu p53），RT-PCR检测mRNA水平，流式细胞仪测定细胞周期阻滞及外源性P53蛋白表达情况，Tunel法检测细胞凋亡，克隆形成率测定辐射后细胞存活率。用携带报道基因的复制缺陷重组腺病毒载体AdCMV-GFP作为对照。结果1Gy X射线照射可较高地增加AdCMV-p53对A375和WM983a细胞系的基因转导效率，转导的外源性野生型p53可在两种细胞中高效表达，并诱导细胞周期G1期阻滞；单纯转导p53对A375（wt p53）细胞无明显诱导凋亡和生长抑制效应，但可部分诱导WM983a（mu p53）细胞凋亡；而转导p53基因48h后给予X射线辐射，两种细胞的克隆存活率较其对照组均明显减低，外源性p53基因对WM983a（mu p53）细胞的辐射增敏作用较A375（wt p53）细胞明显。结论外源性野生型p53基因过表达可增加黑色素瘤细胞系A375和WM983a的辐射敏感性，但对WM983a细胞系的辐射增敏作用高于A375细胞系。表明p53是基因治疗黑色素瘤较好的候选基因。     

外源性野生型p53基因对不同p53功能状态的人肺腺癌细胞株的放射增敏作用

目的 观察外源性野生型p53基因(wtp53)对人肺腺癌细胞株的放射增敏作用,比较不同p53基因状态对照射的影响。 方法 免疫组织化学法、聚合酶链反应-单链构象多态性分析(PCR-SSCP法)筛选p53基因状态不同的两种人肺腺癌细胞系A549及GLC-82,用腺病毒介导wtp53 (Ad-p53)转染后分别给予0、2和4 Gy照射,测定集落形成率,流式细胞仪检测细胞周期分布和凋亡。结果 A549细胞的p53基因正常,而GLC-82细胞的p53基因第7外显子突变,转染后wtp53在两种细胞内均成功表达。Ad-p53对A549及GLC-82细胞抑制率分别为55%和88%,对GLC-82抑制作用较强(P<0.01)。转染Ad-p53后照射,两种细胞集落形成率较对照组明显下降(P<0.001)。流式细胞仪分析Ad-p53使G₁期细胞比例增加和凋亡指数增高,Ad-p53＋照射组最为明显(P<0.001)。结论 Ad-wtp53可以抑制人肺腺癌细胞株的生长,增加其放射敏感性,其放射增敏作用并不依赖于细胞内源性p53基因的状态。     

bcl-2基因转染对大鼠胰岛细胞培养的影响

目的探讨bcl-2基因转染对培养的胰岛细胞凋亡和生物活性的影响。方法用腺病毒介导的基因转染方法把bcl-2转染人胰岛细胞，用RT—PCR和免疫细胞化学方法检测转染细胞中bcl-2的表达，原位末端标记（TUNEL）检测细胞凋亡，台盼蓝测定细胞活度，放免法测定培养液巾胰岛素水平了解胰岛功能。结果转染的胰岛细胞中70％的细胞有bcl-2蛋白的表达，转染细胞的凋亡率为6％，对照组为22死，转染胰岛细胞的活度为91％，对照组为68％，转染胰岛细胞在高糖培养基中胰岛素水平高于对照组。结论腺病毒介导的基冈转染方法能成功转染胰岛细胞，bcl-2基因转染能降低细胞凋亡率，改善胰岛细胞功能。     

X射线诱导人肺腺癌A549细胞凋亡及线粒体DNA基因表达下调

目的 研究不同剂量X线对人肺腺癌A549细胞增殖及凋亡的影响，并检测其线粒体DNA（mtDNA）基因的差异表达。方法 以同步培养的未受照细胞为对照，8MVX线分别以2、4、6和8Gy的吸收剂量照射A549细胞，MTT比色法分析细胞增殖曲线；并于照射后24h，流式细胞仪测定细胞周期分布和凋亡率，电镜观察细胞超微结构，人mtDNA基因表达谱芯片检测靶基因的表达变化。结果X射线抑制A549细胞增殖，以4Gv为显著；随着照射剂量的增加，细胞凋亡率增加，G2／M期细胞比率增加，6和8Gy组表现出G2／M期阻滞，透射电镜下4Gy组可见凋亡的形态改变，8Gy组细胞近碎裂；X射线照射后mtDNA编码基因呈普遍下调表达，包括2Gy组的3种tRNA基因、4Gy组的2种tRNA基因和4种mRNA基因、6Gy组的6种tRNA基因和1种rRNA基因，8Gy组的2种tRNA基因。结论X射线可抑制A549细胞增殖，诱导细胞凋亡及mtDNA编码基因的普遍下调表达。随着辐射剂量的增加，剂量依赖性效应逐步减弱而解除。4Gy为体外研究的相对高效、安全剂量。     

Ad-Rb94联合照射对体外人大肠癌细胞的抑瘤作用

目的 探讨人视网膜母细胞瘤Rb94基因重组腺病毒载体(Ad-Rb94)联合γ射线照射对体外人大肠癌细胞生长的联合抑瘤作用及其机制.方法 将Ad-Rb94于体外转染大肠癌HT29细胞,转染后12h进行4Gy 137Csγ射线照射.实验分组为5组:对照组、β-半乳糖苷酶基因重组腺病毒载体组(Ad-lacZ组)、Ad-Rb94组、照射组和Ad-Rb94联合照射组.用噻唑蓝法检测HT29细胞的生长,用流式细胞术检测HT29细胞的细胞周期和细胞凋亡的变化.结果 当Ad-Rb94有效转染HT29细胞后,从转染第4日开始,照射组和联合照射组细胞生长速率较对照组和Ad-lacZ组缓慢;与Ad-Rb94组和照射组相比,Ad-Rb94联合照射组细胞的生长表现出更强的抑制效应(t=15.02、17.30,P＜0.01).细胞周期结果表明,与对照组、Ad-lacZ组和Ad-Rb94组相比,照射组大量细胞停留在G2期,各组间差异有统计学意义(t=18.65、15.23、16.38,P＜0.01);但Ad-Rb94联合照射组停留在G2期细胞更多(约40％),远高于照射组(t=7.78,P＜0.05).细胞凋亡结果表明,与对照组相比,Ad-Rb94组和照射组细胞凋亡率明显增加(t=16.19、10.72,P＜0.01);Ad-Rb94联合照射组细胞凋亡率最高(21％),与Ad-Rb94组和照射组相比,差异有统计学意义(t=6.17、9.25,P＜0.05).结论 腺病毒介导的Rb94基因联合照射对大肠癌细胞的抑瘤作用具有协同效应,其机制可能是促进细胞G2期阻滞和凋亡.     

重组质粒p-Egr-p16的构建及在SMMC-7721细胞中的辐射诱导表达

目的 构建重组质粒p-Egr-p16并探讨在SMMC-772l细胞中的辐射诱导表达及抗肝癌的作用。方法 用双酶切、粘端连接的方法构建了含有辐射诱导特性的早期反应因子Egr—1和p16的p-Egr-p16的质粒载体，以脂质体介导的方法，将重组载体导人人肝癌SMMC-772l细胞，采用RT-PCR的方法检测了不同剂量^60Coγ射线照射转染后的人肝癌细胞p16基因转录水平的变化和2Gy照射后不同时间的p16基因转录水平的变化。结果经研究证实，1～6Gy照射后p16的转录水平高于对照，在2～4Gy照射后达到峰值，2Gy照射后不同时间均有所增高，在照射后24h增高最明显。结论 2Gy^60Coγ射线照射后p16基因转录水平在2～24h呈现时问依赖性的增高，在24h增高最明显，48和72h逐渐降低，但仍高于对照组。提示^60Coγ射线可激活早期反应生长因子Egr-1，从而介导其下游基因p16的表达增强。     

照射后不同p53基因状态胃癌细胞的G1期阻滞和凋亡

目的　评价抑癌基因ｐ５３（ 野生型ｐ５３） 对照射后人胃癌细胞系（ＢＧＣ８２３） 的Ｇ１ 期阻滞和凋亡的控制作用。方法　３ 种具有不同ｐ５３ 状态的人胃癌细胞系,即转染人野生型ｐ５３ 基因的ＢＧＣ８２３ｗｔｐ５３ 细胞、转染人突变型ｐ５３ 基因的ＢＧＣ８２３ｍｕｔｐ５３ 细胞和转染无ｐ５３ 基因的空载质粒的ＢＧＣ８２３ｖｅｃｔ 细胞,用流式细胞计分析细胞,４Ｇｙ 照射后０、８ 和２４ 小时后各细胞时相分布和凋亡的反应。结果　照射４Ｇｙ 后８ 小时和２４ 小时后的ＢＧＣ８２３ｗｔｐ５３ 细胞出现强烈的Ｇ１ 期阻滞（分别占原细胞总数的６７－９％ 和６１－１ ％） ,而ＢＧＣ８２３ｍｕｔｐ５３ 、ＢＧＣ８２３ｖｅｃｔ 细胞几乎没有Ｇ１ 期阻滞;照射４Ｇｙ 后８ 小时和２４ 小时后的ＢＧＣ８２３ｗｔｐ５３ 细胞出现明显的预示凋亡的亚Ｇ１ 峰,凋亡细胞比例分别达１３－０ ％ 和１５－３ ％ ;而ＢＧＣ８２３ｍｕｔｐ５３ 和ＢＧＣ８２３ｖｅｃｔ 细胞几乎没有出现亚Ｇ１ 峰和凋亡细胞比例都为零。结论　野生型ｐ５３ 基因具有促进照射后肿瘤细胞的Ｇ１ 期阻滞和凋亡作用,而ｐ５３ 变异和缺失则减低了肿瘤细胞对放射线的反应。     

辐射增强启动子调控的p53基因联合照射对肿瘤细胞的作用

目的 研究辐射增强启动子调控的野生型-p53抑癌基因系统联合照射对人肿瘤细胞系HeLa和A549细胞的特异性杀伤作用。方法 构建辐射增强启动子pE6（TATA）-p53,Western blot检测不同射线剂量诱导下人肺腺癌A549细胞系和人宫颈癌HeLa细胞系中P53蛋白的表达水平,筛选出最适的照射剂量;AnnexinV-FITC试剂盒检测肿瘤细胞系早期凋亡率;利用克隆形成实验检测此系统对肿瘤细胞放射敏感性的影响。结果 在HeLa和A549细胞中,P53蛋白表达均受放射线诱导增高,且在6 Gy时辐射诱导活性最高;实验组质粒的细胞早期凋亡率与转染对照组质粒的细胞早期凋亡率相比有明显提高（F=11.018、10.736,P<0.05）。HeLa细胞和A549细胞的放射增敏比（SER）分别为2.56和2.36。结论 辐射增强启动子调控的p53基因系统具有显著的诱导肿瘤细胞凋亡的作用,可以提高肿瘤细胞的辐射敏感性,对肿瘤的治疗提供了新思路。     

Effects of Serum Starvation on Radiosensitivity,Proliferation and Apoptosis in Four Human Tumor Cell Lines with Different p53 Status

PURPOSE: The effects of serum starvation on radiation sensitivity, cell proliferation and apoptosis were investigated with particular consideration of the p53 status. MATERIAL AND METHODS: Four human tumor cell lines, Be11 (melanoma, p53 wild-type), MeWo (melanoma, p53 mutant), 4197 (squamous cell carcinoma, p53 wild-type) and 4451 (squamous cell carcinoma, p53 mutant), were used. After the cells had been incubated in starvation medium (0.5% FCS) for 1-6 days, changes in cell cycle distribution, induction of apoptosis and necrosis, and changes in radiation sensitivity were assessed by two-parameter flow cytometric measurements of DNA-dye-exclusion/Annexin V binding, and a conventional colony assay, respectively. RESULTS: p53 wild-type cell lines showed a decrease in the BrdU labeling index and an increase in the apoptotic cell frequency in starvation medium. p53 mutant cell lines showed a decrease in the BrdU labeling index but no evidence of apoptosis. These cells went into necrosis instead. The radiation sensitivity was increased in 4451 and slightly decreased in Be11 and 4197 in starvation medium. CONCLUSION: These data suggest a functional involvement of p53 in starvation-induced G1-block and apoptosis in tumor cells. Altered radiosensitivity after culture in starvation medium seemed to be explained at least in part by the starvation-induced G1-block. The frequency of starvation-induced apoptosis or necrosis was not correlated with radiation sensitivity.     

野生型p53基因转染卵巢癌SKOV-3细胞对放疗敏感性的影响

目的 探讨γ射线照射抑制平滑肌细胞（SMC）增殖的信号传递途径。方法 培养的动脉平滑肌细胞分别接受吸收剂量为3.5、7．0、14Gy^60Coγ射线照射后，以^3H-TdR掺入法测定平滑肌细胞增殖程度，放射活性法测定蛋白激酶C（PKC）及丝裂素活化蛋白激酶（MAPK）活性。结果 7．0、14Gy^60Coγ射线能明显抑制平滑肌细胞增殖，同时有MAPK、PKC活性明显降低。结论 7．0、14Gy^60Coγ射线抑制血管平滑肌细胞增殖可能是通过降低MAPK、PKC活性途径实现的。     

Preferential radiosensitization in p53-mutated human tumour cell lines by pentoxifylline-mediated disruption of the G2/M checkpoint control

PURPOSE: There is evidence that the duration of the G2/M delay following irradiation is correlated with cell survival. We studied the radiosensitizing potential of pentoxifylline (PTX) and the PTX-mediated modulation of cell-cycle progression dependent on the p53 status of various human tumour cell lines. MATERIALS AND METHODS: The cellular radiosensitivity of human MCF-7 (wild-type p53) and HT-29 (p53-defective) tumour cells, which were exposed to PTX (2 mM) immediately after gamma-irradiation was determined by colony forming assay. The influence on cell cycle progression after irradiation (6 Gy) was assessed by flow cytometric analysis using p53 wild-type MCF-7 and HPR600 cells, and p53-defective HT-29 and WiDr cells. RESULTS: Clonogenic survival assays up to 8 Gy demonstrated that p53-defective HT-29 cells (sensitizer enhancement ratio [SER]=1.54) were sensitized by PTX (2 mM) to a significantly higher degree than p53 wild-type MCF-7 (SER=1.14) cells. Exposure of irradiated (6 Gy) cells to PTX (2 mM) resulted in abrogation of the radiation-induced G2/M arrest in the p53-defective HT-29 and WiDr cells, whereas the p53 wild-type-expressing MCF-7 and HPR600 cells showed less significant impairment of the G2/M checkpoint. In HT-29 cells, the rate of transition into mitosis was even higher than in the sham-treated control cells. G2/M abrogation was accompanied by an increase of apoptosis only in HPR600 cells. CONCLUSIONS: Since PTX was less effective in cells expressing intact p53, the application of PTX suggests a promising strategy of pharmacological disruption of the G2/M checkpoint control by which preferentially radiation-resistant tumours with defective p53 function might be rendered more sensitive to ionizing radiation.     

Preferential radiosensitization in p53-mutated human tumour cell lines by pentoxifylline-mediated disruption of the G2/M checkpoint control

Purpose : There is evidence that the duration of the G2/M delay following irradiation is correlated with cell survival. We studied the radiosensitizing potential of pentoxifylline (PTX) and the PTX-mediated modulation of cell-cycle progression dependent on the p53 status of various human tumour cell lines. Materials and methods : The cellular radiosensitivity of human MCF-7 (wild-type p53) and HT-29 (p53-defective) tumour cells, which were exposed to PTX (2 mM) immediately after γ-irradiation was determined by colony forming assay. The influence on cell cycle progression after irradiation (6 Gy) was assessed by flow cytometric analysis using p53 wild-type MCF-7 and HPR600 cells, and p53-defective HT-29 and WiDr cells. Results : Clonogenic survival assays up to 8 Gy demonstrated that p53-defective HT-29 cells (sensitizer enhancement ratio [SER]=1.54) were sensitized by PTX (2 mM) to a significantly higher degree than p53 wild-type MCF-7 (SER=1.14) cells. Exposure of irradiated (6 Gy) cells to PTX (2 mM) resulted in abrogation of the radiation-induced G2/M arrest in the p53-defective HT-29 and WiDr cells, whereas the p53 wild-type-expressing MCF-7 and HPR600 cells showed less significant impairment of the G2/M checkpoint. In HT-29 cells, the rate of transition into mitosis was even higher than in the sham-treated control cells. G2/M abrogation was accompanied by an increase of apoptosis only in HPR600 cells. Conclusions : Since PTX was less effective in cells expressing intact p53, the application of PTX suggests a promising strategy of pharmacological disruption of the G2/M checkpoint control by which preferentially radiation-resistant tumours with defective p53 function might be rendered more sensitive to ionizing radiation.     

Radiation induced chromosome aberrations and clonogenic survival in human lymphoblastoid cell lines with different p53 status

PURPOSE: To better understand the relation of radiation induced chromosome aberrations and clonogenic survival in cells with different p53 status. MATERIALS AND METHODS: The human lymphoblasts TK6 and WTK1 were derived from the same donor, but differ in radiosensitivity, p53 status and kinetics of apoptosis. TK6 cells have wild type p53 (p53wt), whereas WTK1 cells have a mutated, non-functional p53 (p53mut). Additionally, a HPV16 E6 transfected TK6 cell line (TK6E6), which is also negative for p53 function (p53neg), was studied. The cells were irradiated, incubated with colcemid, hypotonically lysed and fixed. After staining with Giemsa, asymmetric chromosomal exchange type aberrations were counted in 50 mitoses each per dose point (0 to 4 Gy). Clonogenic survival was determined using the microtiter plate assay. All experiments were performed in triplicate. RESULTS: WTK1 (p53mut) show a higher spontaneous frequency of chromosome aberrations than TK6 (p53wt). No significant differences were noted in radiation induced aberration frequency. TK6E6 (p53neg) show comparable aberration frequencies like TK6. However, the dose required to reduce survival to 10% (D10) was about 2 Gy for TK6 and TK6E6, whereas the D10 for WTK1 was approximately 3 Gy. CONCLUSION: The p53 status influences the radiosensitivity in this lymphoblast cell system showing a high rate of radiation induced apoptosis. Cells with p53mut (WTK1), survive with a damaged genome, because they do not undergo apoptosis to loose their clonogenicity. There was no difference between the p53wt (TK6) and p53neg cells (TK6E6) suggesting a suppression of radiation induced apoptosis by p53mut.     

Adenovirus-mediated wild-type p53 gene expression radiosensitizes non-small cell lung cancer cells but not normal lung fibroblasts

Purpose : We compared the ability of adenoviral-mediated wildtype p53 RPR/INGN201(Ad5/CMV/p53) to radiosensitize nonsmall cell lung carcinoma (NSCLC) and normal lung fibroblast cells. Materials and methods : NSCLC cell lines (A549 and H322) and human lung fibroblast cells (MRC-9 and CCD-16) were used in this study. Radiosensitivity was determined by clonogenic assay and tumor growth delay. Expression of p53, Bax, and p21 WAF1 protein were evaluated by immunoblot. A FITC conjugate of annexin V was used for flow cytometric detection of apoptosis. Results : Clonogenic and apoptotic assays indicated that Ad5/CMV/p53 enhanced the radiosensitivity of both NSCLC cell lines. On the other hand, the two normal human fibroblast cell lines appeared to be resistant to the cytotoxic effects of Ad5/CMV/p53 and were not radiosensitized compared to the NSCLC cells. According to immunoblot analysis, Bax expression was increased in the NSCLC cells treated with the combination therapy; Bax expression, however, was unchanged in normal cells. In in vivo studies, tumor growth suppression was enhanced by this combination strategy in xenograft tumors growing in nude mice compared to Ad5/CMV/p53 or radiation therapy when used alone. Conclusions : Our data indicate that therapy using Ad5/CMV/p53 and irradiation in combination is more effective than either treatment when used alone on NSCLC cells, is not limited to cells with defective endogenous p53, and does not enhance the radiosensitivity of normal cells.     

Adenovirus-mediated wild-type p53 gene expression radiosensitizes non-small cell lung cancer cells but not normal lung fibroblasts

PURPOSE: We compared the ability of adenoviral-mediated wild-type p53 RPR/INGN201(Ad5/CMV/p53) to radiosensitize non-small cell lung carcinoma (NSCLC) and normal lung fibroblast cells. MATERIALS AND METHODS: NSCLC cell lines (A549 and H322) and human lung fibroblast cells (MRC-9 and CCD-16) were used in this study. Radiosensitivity was determined by clonogenic assay and tumor growth delay. Expression of p53, Bax, and p21WAF1 protein were evaluated by immunoblot. A FITC conjugate of annexin V was used for flow cytometric detection of apoptosis. RESULTS: Clonogenic and apoptotic assays indicated that Ad5/CMV/p53 enhanced the radiosensitivity of both NSCLC cell lines. On the other hand, the two normal human fibroblast cell lines appeared to be resistant to the cytotoxic effects of Ad5/CMV/p53 and were not radiosensitized compared to the NSCLC cells. According to immunoblot analysis, Bax expression was increased in the NSCLC cells treated with the combination therapy; Bax expression, however, was unchanged in normal cells. In in vivo studies, tumor growth suppression was enhanced by this combination strategy in xenograft tumors growing in nude mice compared to Ad5/CMV/p53 or radiation therapy when used alone. CONCLUSIONS: Our data indicate that therapy using Ad5/CMV/p53 and irradiation in combination is more effective than either treatment when used alone on NSCLC cells, is not limited to cells with defective endogenous p53, and does not enhance the radiosensitivity of normal cells.