小干扰RNA靶向MIF对胃癌细胞SGC 7901增殖和凋亡的影响#br#

目的探讨靶向巨噬细胞移动抑制因子（MIF）的小干扰RNA（siRNA）对胃癌细胞SGC 7901增殖和凋亡的影响。 方法取对数生长期的SGC 7901细胞，采用脂质体法分别转染靶向人MIF的siRNA（siMIF组）或阴性对照序列（NC组），48 h后采用Western blotting检测MIF蛋白的表达情况，MTT法观察转染后24、48、72 h的细胞增殖情况，流式细胞仪检测转染后72 h的细胞凋亡率，Western blotting检测凋亡相关蛋白Bcl 2和Bax的表达变化。 结果siMIF组转染48 h后的MIF相对表达量为0321±0104，低于NC组的1078±0212，差异有统计学意义（P＜005）。siMIF组转染48～72 h后的细胞增殖率低于NC组，差异有统计学意义（P＜005）。转染MIF siRNA 72 h后，siMIF组的细胞凋亡率为（235±36）％，高于NC组的（47±17）％，差异有统计学意义（P＜005）。siMIF组Bcl 2的相对表达量为0663±0209，低于NC组的1129±0178，而Bax相对表达量为0981±0225，高于NC组的0587±0254，以上差异均有统计学意义（P＜005）。 结论siRNA靶向沉默MIF能够降低SGC 7901细胞中MIF蛋白表达，抑制SGC 7901细胞的增殖并促进凋亡，在胃癌的靶向治疗中有一定前景。     

组蛋白脱乙酰基酶抑制剂苯丁酸钠对基因PIG7的表达作用研究

目的研究组蛋白脱乙酰基酶抑制剂苯丁酸钠（PB）作用于Kasumi-1细胞后PIG7基因的表达变化及其与细胞分化凋亡的关系。方法采用半定量RT—PCR检测1,2,3mmol／LPB作用后24h、48hKasumi-1细胞PIG7基因的表达水平,同步观察细胞的形态变化,流式细胞仪检测CD11b、CD13和AnnexinV／PI表达水平。结果处理前PIG7低表达不能检测到,处理后均明显升高（P〈0．05）,不同浓度、作用时间间差异无统计学意义（P〉0．05）;细胞形态呈现分化凋亡改变;CD11b、CD13表达增加（P〈0．05）,AnnexinV^＊／PI^-增加（P〈0．05）。结论组蛋白脱乙酰基酶抑制剂苯丁酸钠作用后Kasumi-1细胞PIG7基因的表达增加,同时细胞发生分化凋亡,PB可能通过上调PIG7的表达引起上述生物学效应。     

小干扰RNA靶向MIF对胃癌细胞SGC 7901增殖和凋亡的影响#br#

目的探讨靶向巨噬细胞移动抑制因子（MIF）的小干扰RNA（siRNA）对胃癌细胞SGC 7901增殖和凋亡的影响。 方法取对数生长期的SGC 7901细胞,采用脂质体法分别转染靶向人MIF的siRNA（siMIF组）或阴性对照序列（NC组）,48 h后采用Western blotting检测MIF蛋白的表达情况,MTT法观察转染后24、48、72 h的细胞增殖情况,流式细胞仪检测转染后72 h的细胞凋亡率,Western blotting检测凋亡相关蛋白Bcl 2和Bax的表达变化。 结果siMIF组转染48 h后的MIF相对表达量为0321±0104,低于NC组的1078±0212,差异有统计学意义（P＜005）。siMIF组转染48～72 h后的细胞增殖率低于NC组,差异有统计学意义（P＜005）。转染MIF siRNA 72 h后,siMIF组的细胞凋亡率为（235±36）％,高于NC组的（47±17）％,差异有统计学意义（P＜005）。siMIF组Bcl 2的相对表达量为0663±0209,低于NC组的1129±0178,而Bax相对表达量为0981±0225,高于NC组的0587±0254,以上差异均有统计学意义（P＜005）。 结论siRNA靶向沉默MIF能够降低SGC 7901细胞中MIF蛋白表达,抑制SGC 7901细胞的增殖并促进凋亡,在胃癌的靶向治疗中有一定前景。     

明胶/细菌纤维素复合材料生物相容性的实验研究

目的探讨明胶/细菌纤维素复合支架材料生物相容性。方法将明胶（Gel）和细菌纤维素（BC）通过物理混合法和化学交联法制备成物理组Gel/BC和化学组Gel/BC,以BC为对照组,对3种支架材料进行细胞粘附实验,MTT比色法测定细胞增殖情况,扫描电镜观察细胞的生长情况。将3种材料分别植入20只雄性新西兰大白兔下颌骨缺损模型中,分别于4,8,12 w进行组织学染色分析、电镜扫描指标检测,统计学分析,比较各组修复骨缺损的效果。结果与对照组比较,实验组细胞增殖有统计学差异（P〈0.05）,SEM观察可见3组材料中均有细胞的粘附,细胞在物理组Gel/BC上生长状态好于其他两组,胞体均较饱满,伪足较多。体内植入后分别于4,8,12 w经扫描电镜和组织学观察,观察期间材料和骨组织由纤维结缔组织构成,物理组Gel/BC更加致密,空隙更小,骨小梁,新生骨均优于对照组。结论物理组Gel/BC对骨的修复效果最好,化学组Gel/BC次之,均优于BC。明胶/细菌纤维素复合支架材料具有良好生物相容性,有望成为新一代骨组织工程替代材料。     

DON 对胃癌细胞HGC-27 细胞周期和凋亡的影响

 目的 探讨脱氧雪腐镰刀菌烯醇（DON）对体外培养胃癌细胞HGC-27细胞周期和凋亡的影响。方法 体外培养的胃癌细胞HGC-27经50、100、1000、2000μg／L DON处理12h、24h、48h，应用流式细胞术（FCM）进行细胞周期分析，检测凋亡情况及其量效关系，Western blot检测凋亡相关蛋白Bax、Bcl-2和Caspase-3的表达情况。结果 FCM检测结果表明，较高浓度（1000和2000μg／L）DON处理对细胞周期分布的影响随处理时间不同有明显差异。DON处理12h，可明显降低G0／G1细胞百分率、增加S期细胞百分率。处理时间延长至24h和48h，则表现为G0／G1细胞百分率增加，S期细胞百分率降低（P〈0．05）。DON处理24h和48h，各DON实验组HGC-27细胞凋亡率均高于对照组，在50～2000ug／L浓度范围内，凋亡率随着DON处理浓度的升高而升高。Western blot检测凋亡相关蛋白结果显示，DoN处理12、24和48h，Bax和Caspase-3蛋白表达均明显升高，而Bcl-2蛋白表达降低。结论 DON处理可影响体外培养的胃癌细胞象HGC-27细胞的细胞周期分布，其作用依DON浓度和作用时间的不同而有差异。同时DON可诱导HGC-27细胞凋亡，上调Bax和Caspase-3蛋白表达和下调Bcl-2蛋白表达可能是其诱导细胞凋亡的机制之一。     

依托泊苷对人骨髓瘤细胞 RPMI8226增殖与凋亡的影响

目的：探讨依托泊苷对人骨髓瘤细胞 RPMI8226的增殖抑制作用及其分子机制。方法：将依托泊苷作用于骨髓瘤细胞,用 MTT 法检测细胞增殖抑制率,光学显微镜和电子显微镜观察细胞形态及超微结构变化,流式细胞术检测细胞凋亡率和细胞周期分布,半定量 RT －PCR 检测 Bax 及 Caspase －3 mRNA 表达量的变化,Western blot 检测 Bax 及 Caspase －3蛋白表达量变化。结果：依托泊苷可抑制 RPMI8226细胞增殖,抑制率呈时间（r ＝0．926）和浓度（r ＝0．938）依赖性增强。24h 后在光学显微镜下可见依托泊苷组细胞数量减少,排列紊乱,细胞形态变得不规则,可见凋亡细胞及坏死细胞。48h 电子显微镜下可见细胞典型凋亡改变,凋亡小体形成。流式细胞术检测结果显示,依托泊苷组 RPMI8226细胞凋亡率明显增高（P ＜0．05）;依托泊苷作用48h 后将 RPMI8226细胞阻滞于 S 期（P ＜0．05）;依托泊苷作用48h,Bax、Caspase －3 mRNA 及蛋白表达量增加（P ＜0．05）。结论：依托泊苷可诱导 RPMI8226细胞凋亡,可能与细胞周期阻滞,激活细胞内、外源性凋亡通路有关。     

GOLPH3沉默对顺铂诱导的人上皮性卵巢癌 A2780／DDP 细胞凋亡的影响

目的：探究 GOLPH3对顺铂诱导的人上皮性卵巢癌 A2780／DDP 细胞凋亡的影响。方法：不同浓度顺铂处理 A2780和 A2780／DDP 细胞72h,MTT 检测半数抑制浓度 IC50,Western blot 检测 GOLPH3的表达。将培养细胞分为4组：A2780组及 A2780／DDP 组（对照组、Scrambled siRNA 组、GOLPH3 siRNA 组）。40μmol／L顺铂处理48h 后,MTT 检测对细胞活性的影响,流式细胞术检测对细胞凋亡的影响,Western blot 检测对Caspase －3、p －Akt 和 p －mTOR 蛋白表达的影响。Western blot 检测 mTOR 抑制剂雷帕霉素（Rapamycin）和PI3K／Akt 抑制剂（LY294002）对 Caspase －3蛋白表达的影响。结果：顺铂处理72h 时,A2780和 A2780／DDP细胞的 IC50分别为9．8μmol／L 和60．14μmol／L。与 A2780组相比,A2780／DDP 组 GOLPH3蛋白表达明显增加（P ＜0．05）。GOLPH3 siRNA 转染可显著下调 A2780／DDP 细胞中 GOLPH3蛋白的表达（P ＜0．05）。顺铂处理后,与 A2780／DDP 对照组相比,A2780组和 A2780／DDP 细胞 GOLPH3 siRNA 转染组细胞活性显著降低,顺铂敏感性增加,细胞凋亡率和 Caspase －3蛋白表达上调,p －Akt 和 p －mTOR 蛋白表达下调;LY294002和 Ra-pamycin 处理均显著增加 Caspase －3蛋白表达（P ＜0．05）。结论：GOLPH3沉默可通过抑制 Akt／mTOR 激活促进顺铂诱导的 A2780／DDP 细胞凋亡。     

不同肌腱处理方法对同种异体肌腱生物学性能的影响

目的探讨不同处理方法对同种异体肌腱生物学性能的影响,并筛选最佳处理方法。方法应用四种处理方法:1%TnBP+1%Triton X-100(A组)、0.5%胰蛋白酶+0.5%Triton X-100(B组)、1%TnBP(C组)、1%Triton X-100+70%异丙醇(D组)分别对新鲜肌腱进行处理,组织学染色观察去细胞效果;CCK8法检测细胞毒性;扫描电镜观察细胞黏附情况;皮内刺激实验评价体内相容性。结果采用0.5%胰蛋白酶+0.5%Triton X-100去除细胞最彻底,纤维排列整齐,结构完整,其它组均观察到有少部分细胞残留;CCK8结果显示,A组和C组处理的肌腱为二级细胞毒性,B组和D组处理的肌腱为1级细胞毒性。扫描电镜结果显示A组和C组处理的肌腱上细胞黏附数量较少,且基本呈圆形;D组处理的肌腱上细胞黏附数量较多,细胞状态较好;B组处理的肌腱上细胞黏附数量最多,细胞成片生长,状态较好。皮内刺激实验结果显示,各组均出现红肿和焦痂。结论在四种肌腱处理方法中,0.5%胰蛋白酶+0.5%Triton X-100的处理方法最为理想。     

辛伐他汀对人乳腺癌细胞MCF-7的生长抑制作用及机制研究

目的 探讨辛伐他汀（SVA）体外对乳腺癌细胞MCF-7的生长抑制作用及其可能的机制。 方法 选用人乳腺癌MCF-7细胞进行体外培养,采用四甲基偶氮唑盐法检测不同浓度SVA（0、3.25、6.25、12.5、25、50和100 μmol／L）处理MCF-7细胞24、48、72 h后的增殖抑制作用,荧光染色法观察SVA（0、2和4 μmol／L）处理MCF-7细胞48 h后的凋亡形态学变化,流式细胞仪测定SVA（0和4 μmol／L）处理MCF-7细胞48 h后的细胞周期变化,免疫印迹法分析SVA（0、2、4和8 μmol／L）处理MCF-7细胞72 h后细胞内Bcl-2和Bax蛋白水平的表达。结果 不同浓度SVA处理不同时间后,MCF-7细胞的增殖明显受到抑制,且增殖抑制作用呈时间和浓度依赖性;荧光显微镜观察发现SVA能够诱导MCF-7细胞出现核固缩、染色质凝集等凋亡形态学改变。流式细胞仪检测细胞周期显示,SVA阻滞MCF-7细胞于G0／G1期。免疫印迹 结果 显示,SVA处理组的Bcl-2蛋白表达水平低于对照组,Bax蛋白表达水平明显高于对照组,且随SVA浓度的增高,Bcl-2蛋白水平逐渐降低,Bax蛋白水平逐渐升高。结论 SVA对人乳腺癌MCF-7细胞具有增殖抑制作用,且呈浓度和时间依赖性,其抗肿瘤机制可能与诱导细胞周期阻滞、下调Bcl-2蛋白及上调Bax蛋白表达有关。     

香加皮杠柳苷对人食管癌细胞TE-13生长抑制作用

目的：分析中药香加皮醇提物杠柳苷（periplocin from cortex periplocae，CPP）对食管癌细胞株TE-13的生长抑制作用，探讨其诱导细胞周期阻滞的机制。方法：应用MTr法检测CPP对TE-13细胞的抑制作用；Gimsa染色法分析TE-13细胞的形态学变化；FCM法检测细胞周期分布和凋亡率；Western印迹法检测TE-13细胞经药物处理前后细胞周期蛋白依赖性激酶CDK4、CDK2蛋白表达的变化。结果：CPP对TE-13细胞增殖具有明显的抑制作用（P〈0．01），并呈时间和浓度依赖性，药物浓度越大，作用时间越长，抑制效应越强，CPP作用48h时，对TE-13细胞的半数抑制浓度（IC50）为0．61μg／mL。经2μg／mL的CPP作用48h后，TE-13细胞发生明显的凋亡形态学变化；G0／G1期细胞明显增多（P〈0．01），S期细胞明显减少（P〈0．01），G2／M期细胞没有明显变化（P〉0．05）。不同浓度CPP作用48h后能降低TE-13细胞中CDK4蛋白的表达（P〈0．01），对CDK2蛋白的表达则没有明显影响（P〉0．05）。结论：CPP能显著抑制，TE-13细胞的增殖，其作用机制可能与CPP诱导细胞周期阻滞和细胞凋亡有关。     

仙灵冲剂治疗化疗后血小板减少小鼠的实验研究

目的：观察自拟中药仙灵冲剂治疗化疗后血小板减少小鼠的血小板计数水平及白介素 １１（ＩＬ-１１）、血小板生成素（ＴＰＯ）表达水平。方法：将实验小鼠分为空白对照组、模型组、巨和粒组和仙灵冲剂高、中、低剂量组,构建血小板减少的模型后分别进行相应理,于实验第１４天观察血小板计数水平及ＩＬ-１１、ＴＰＯ表达水平。结果：仙灵冲剂高剂量组、中剂量组血小板计数均高于模型组（Ｐ＜０.０５）,低剂量组高于模型组但无统计学意义（Ｐ＞０.０５）,仙灵冲剂各组ＩＬ-１１、ＴＰＯ表达水平均高于模型组。结论：仙灵冲剂可以提高小鼠骨髓ＩＬ-１１及ＴＰＯ表达,促进血小板的升高。     

Ultrastructure and cytokinetics of leukemic myeloblasts containing giant granules.

Leukemic myeloblasts containing abnormal granules were studied with ultrastructural, cytochemical, and thymidine labeling techniques to evaluate defects in granulogenesis and proliferation. Giant granules (1 to 3 micron in diameter) and Auer rods were observed in leukemic cells from two patients, and only rarely were both abnormal granule types observed in the same cell. The lysosomal origin of these abnormal granules was demonstrated by their content of peroxidase, esterase, and anionic glycoconjugates. Fusion of small dense granules (less than 0.2 micron in diameter) appeared to be increased in cells containing Auer rods and/or giant granules, but fusion of intact primary granules (0.2 to 0.4 micron in diameter) and sequestration of cytoplasmic contents were observed only in giant granules and not in Auer rods. Although the small granules that fused to form giant granules and Auer rods appeared similar, there was no evidence for transformation of giant granules into Auer rods. In one patient, cells with abnormal granules could easily be distinguished from the larger population of cells that lacked abnormal granules. The perturbation of these two distinct populations by chemotherapy was evaluated with thymidine labeling experiments. A high percentage (2- or 3-fold greater) of the abnormally granulated myeloblasts incorporated tritiated thymidine when compared to myeloblasts without abnormal granules in the same specimen. This difference could have resulted from an underlying metabolic defect which affected both granulogenesis and cell division. These results demonstrate that the formation of giant granules in leukemic cells is morphologically similar to that observed in the Chediak-Higashi syndrome and that leukemic cells with abnormal granules may differ cytokinetically from uninvolved leukemic cells.     

Histone deacetylase inhibitor (HDACI) PCI-24781 potentiates cytotoxic effects of doxorubicin in bone sarcoma cells

Purpose

To better understand the mechanisms of cytotoxicity and cell death induced by HDACI PCI-24781 in bone sarcoma cells.

Methods

Four bone sarcoma cell lines were treated with PCI-24781, and the cytotoxicity was investigated. Further, accumulation of acetylated histones, p21, and PARP cleavage were evaluated in PCI-24781-treated cells. The synergistic effect of PCI-24781 to doxorubicin and its mechanism was investigated in bone sarcoma cells.

Results

MTT assay demonstrated that the growth of bone sarcoma cells was inhibited after treatment with PCI-24781. Accumulation of acetylated histones, p21, and PARP cleavage were found in PCI-24781-treated cells. Expression of DNA repair protein RAD51 was inhibited, and the expression of apoptosis protein GADD45α was induced by PCI-24781 in bone sarcoma cells. Bone sarcoma cells treated with PCI-24781 become more sensitive to doxorubicin. The caspase-3/7 activity was increased with doxorubicin and PCI-24781 treatment in these cells.

Conclusions

HDACI PCI-24781 has a synergistic effect on doxorubicin-induced apoptosis in bone sarcoma cells.     

Isolation and characterization of cytotoxic granules from human lymphokine (interleukin 2) activated killer cells

Cytotoxic granules were isolated from human lymphokine-activated killer (LAK) cells and analyzed for their biochemical properties. Isolated granules of approximately 85-95% purity were obtained by differential centrifugation followed by discontinuous Percoll gradient centrifugation. The murine lymphocyte granule marker N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase as well as cytotoxic activity toward the human tumor cell lines K562, Raji, Daudi, and CEM were associated with LAK granule fractions. Granule-associated N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase activity increased in recombinant interleukin 2 expanded human LAK cells in parallel with cytotoxic activity for Raji tumor cell targets. Cytotoxic LAK cell granules mediated calcium-dependent killing of the tumor cell lines K562, Raji, Daudi, and CEM. However, no calcium-dependent hemolytic activity was found. Preincubation of human granules with calcium, a treatment which totally inactivates the hemolytic and cytotoxic activity of murine lymphocyte granules [perforin 1 (P1)] had no effect on human LAK granule cytotoxicity for nucleated cells. Human LAK granules appear to contain P1 detected as cross-reactive antigen detected by mouse anti-P1 and human anti-C9 in Western blot analysis. In addition, Northern blot analysis of polyadenylated RNA isolated from human LAK cells using a murine P1 complementary DNA probe showed a cross-hybridizing 2.8- to 3.0-kilobase mRNA species identical in size to murine P1 mRNA. These results demonstrate that despite similar biochemical composition, functional differences exist between human and murine cytotoxic granules. Human LAK granules were synthesized in response to recombinant interleukin 2 activation and appeared in parallel with cytotoxicity for tumor targets, suggesting an important role for LAK granules in tumor cell cytotoxicity by human LAK cells.     

Carcinoid tumor of the gallbladder associated with adenocarcinoma

A case of carcinoid tumor of the gallbladder associated with adenocarcinoma in a 56-year-old man is reported and a review of the literature is made. The tumor was a polypoid mass with a size of 5.5 X 4.0 X 2.8 cm. Histologically, the tumor showed carcinoid and adenocarcinoma with areas of mucous change. Tumor cells containing argyrophil granules were observed in both carcinoidal and adenocarcinomatous areas, but no argentaffin granules were detected in either of the neoplastic areas. Some of the tumor cells had both argyrophil granules and mucin in the same cytoplasm. The electron microscopic study revealed several tumor cells containing neurosecretory granules; however, no clinical signs of hormonal activities of the tumor were observed. The patient died of generalized bone metastases 16 months after surgery. This appears to be the second case of composite tumor of the gallbladder.     

In vivo animal histomorphometric study for evaluating biocompatibility and osteointegration of nano-hydroxyapatite as biomaterials in tissue engineering

The coming decade will bring new and even more complex advances that will transform oral and maxillofacial surgery practice if the specialty is capable of transferring the advances of basic science into clinical practice. Such advances include those in tissue engineering and nanotechnology. Three groups of eight animals (rats), each was evaluated by grouting bone graft substitutes into 3 mm holes that were made into the anteromedialtibialmetaphyses of rats. Two different formulations varying as to the type of hydroxyapatite (HA) were used; Group 1: Nano-hydroxyapatite, Group 2: Control with HA only. Group 3: Control without any bone graft substitutes (empty defects). Animals of each of the three groups were sacrificed in groups of eight at postoperative week four. Histologic analysis revealed superior biocompatibility and osteointegration of bone graft substitutes when nanohydroxyapatite was employed. At four weeks, there was more reactive new bone formation in this group when compared to the hydroxyapatite group. The control group showed incomplete closure of the defect. This study demonstrated that nano-hydroxyapatite improves the bioactivity of bone implant and repair materials. Nanohydroxyapatite has good biocompatibility, finer mechanical properties, adjustable degradation properties, good osteointegration and offers a wide range of potential applications in the tissue engineering. KEY WORDS: Osteointegration- Nano-Hydroxyapatite- Biomaterials- Tissue engineering.     

急性嗜碱粒细胞白血病及其超微结构

报告了一例急性嗜碱粒细胞白血病及其超微结构，观察了嗜碱早幼粒、中幼粒、晚幼粒及成熟嗜碱粒细胞。超微结构结果：骨髓嗜碱粒细胞的颗粒基质易水解，固定困难，它可能是嗜碱颗粒的特点，其他细胞的颗粒未见抽提现象。     

Cycloheximide-induced modulation of TNF-mediated cytotoxicity in sensitive and resistant ovarian tumor cells

The mechanism of sensitivity and resistance of various ovarian carcinoma lines to recombinant tumor necrosis factor (rTNF)-mediated cytotoxicity has been investigated using a 24-h 51Cr-release assay. The cell line PA-1 is sensitive to TNF in a dose-dependent manner, whereas the cell line SKOV-3 is resistant to TNF even at high concentrations. The simultaneous addition of TNF and cycloheximide (CHX) in the assay converted the resistant SKOV-3 line into a sensitive line, but no detectable change was observed with PA-1. rTNF inhibited DNA, RNA, and protein synthesis of the sensitive PA-1 line, whereas it had no effect on SKOV-3. This finding was not due to differences in the expression of TNF receptors, as both cell lines expressed equivalent numbers of receptors. The addition of CHX to TNF resulted in suppression of DNA, RNA, and protein synthesis in both the sensitive and the resistant cell lines. Pretreatment of the cell line with TNF for 3 h and subsequent washing resulted in significant cytotoxicity of the sensitive PA-1 line and some cytotoxicity against SKOV-3. However, if the cells were pretreated with CHX for 3 h followed by rTNF for 24 h, a significant decrease in cytotoxicity was observed in both cell lines. Under these conditions, there was no significant inhibition of DNA, RNA, or protein synthesis. Pretreatment of cells for 24 h with TNF and 24 h with CHX resulted in augmentation of the cytotoxicity of PA-1 and SKOV-3, whereas pretreatment for 24 h with CHX followed by 24 h with TNF resulted in no cytotoxicity. Cells pretreated with CHX for 24 h showed poor binding of [125]I-TNF and poor internalization, whereas cells pretreated for 24 h with TNF showed marked enhancement of internalization. The sensitivity of freshly derived ovarian carcinoma lines to TNF and CHX demonstrated that TNF-resistant cells became more sensitive if treated with CHX. These results demonstrate the potential use of metabolic inhibitors in increasing the sensitivity of fresh ovarian tumor cells to TNF.     

Influence of WR2721 on DNA cross-linking by nitrogen mustard in normal mouse bone marrow and leukemia cells in vivo

In previous studies we showed that WR2721 enhanced nitrogen mustard (HN2) cytotoxicity to AKR mouse leukemia. Simultaneously, it protected normal bone marrow from drug cytotoxicity. In this study, the method of alkaline elution was used to measure the modifications of HN2 induced DNA damage in the same animal model. In leukemia cells, no significant differences in DNA-DNA interstrand cross-links were observed between mice treated with WR2721 and HN2 and mice treated with HN2 alone. In normal bone marrow, DNA-DNA cross-linking was decreased by about 50% in mice treated by WR2721 and HN2. The difference was significant (P = 0.01). In leukemia, half-time of repair was 73 min for HN2 and 83 for WR2721 and HN2 treated mice, while in normal bone marrow, respectively, 73 and 64 min were calculated. WR2721 modulation significantly decreases DNA-protein cross-links in leukemia cells (P less than 0.05). This decrease was observed for early as well as for late DNA-protein cross-links. In normal bone marrow cells, only early DNA-protein cross-links were decreased. The meaning of this observation is unclear.