A novel treatment for cancer patients with homozygous deletions of BRCA1 and BRCA2 is to use drugs that inhibit the enzyme poly(ADP-ribose) polymerase (PARP). Specific inhibition of PARP-1 can induce synthetic lethali...A novel treatment for cancer patients with homozygous deletions of BRCA1 and BRCA2 is to use drugs that inhibit the enzyme poly(ADP-ribose) polymerase (PARP). Specific inhibition of PARP-1 can induce synthetic lethality in irradiated cancer cells while theoretically leaving normal tissue unaffected. We recently demonstrated in a cell survival assay that lymphoblastoid cells with mono-allelic mutations of BRCA1 were hypersensitive to gamma radiation in the presence of the PARP-1 inhibitor Olaparib compared to normal cells and mono-allelic BRCA2 cells. To determine if the enhanced radiation sensitivity was due to a persistence of DNA strand breaks, we performed γ-H2AX foci analysis in cells derived from two normal individuals, three heterozygous BRCA1 and three heterozygous BRCA2 cell lines. Cells were exposed to 2 Gy gamma radiation in the presence or absence of 5 μM Olaparib. Using immunofluorescence and imaging flow cytometry, foci were measured in untreated cells and at 0.5, 3, 5 and 24 hours post-irradiation. In all lymphoblastoid cells treated with 2 Gy gamma radiation, there was a predictable induction of DNA strand breaks, with a modest but significant retention of foci over 24 hours in irradiated cells treated with Olaparib (ANOVA P < 0.05). However, in mono-allelic BRCA1 cells, there was a failure to fully repair DNA double-strand breaks (DSB) in the presence of Olaparib, evidenced by a significant retention of foci at 24 hours’ post irradiation (t-Test P These data show that the cellular hypersensitivity of mono-allelic BRCA1 lymphoblastoid cells to gamma radiation in the presence of the Olaparib is due to the retention of DNA DSB. These data may indicate that patients with inherited mutations in the BRCA1 gene treated with radiotherapy and PARP-1 inhibitors may experience elevated radiation-associated normal tissue toxicity.展开更多
【目的】评价不同吉富罗非鱼群体的遗传多样性,筛选出鉴别不同群体的分子标记,为吉富罗非鱼种质资源保护及其新品种选育提供理论依据。【方法】对48尾来自两个不同群体的吉富罗非鱼进行尾静脉采血,抽提其基因组DNA,应用微卫星标记技术...【目的】评价不同吉富罗非鱼群体的遗传多样性,筛选出鉴别不同群体的分子标记,为吉富罗非鱼种质资源保护及其新品种选育提供理论依据。【方法】对48尾来自两个不同群体的吉富罗非鱼进行尾静脉采血,抽提其基因组DNA,应用微卫星标记技术判定其等位基因和基因型,然后采用Gen Al Ex 6.2、Cervus 3.0和Populations软件进行数据分析,计算有效等位基因数（Ne）等群体遗传多样性相关参数,对两个吉富罗非鱼群体进行遗传差异分析。【结果】从50对微卫星引物中筛选出23对扩增产物稳定、条带清晰、特异性好的引物,扩增出的DNA片段大小在110~388 bp。利用23个微卫星位点,从两个吉富罗非鱼群体中共检测到89个等位基因和163种基因型,平均每个位点的等位基因数（Na）3.8个、基因型7.1种。两个吉富罗非鱼群体的平均观察杂合度（Ho）分别为0.6383和0.5957,平均期望杂合度（He）分别为0.5759和0.5559;23个位点在两个群体中平均多态信息含量（PIC）分别为0.5131和0.4942,平均固定系数（FIS）分别为-0.1184和-0.0718;两个群体间的遗传距离（DA）为0.1287,平均遗传分化系数（FST）为0.135。UNH911、GM141、GM287、GM134等4个位点在两个群体中扩增的条带存在明显差异。【结论】两个吉富罗非鱼群体遗传多样性水平较高,均存在杂合子过剩现象,群体间遗传分化程度中等,具有较强的环境适应能力,且选育空间大。UNH911、GM141、GM287、GM134等4个微卫星位点可作为鉴别两个吉富罗非鱼群体的分子标记,也可用于分子标记辅助育种研究。展开更多
文摘A novel treatment for cancer patients with homozygous deletions of BRCA1 and BRCA2 is to use drugs that inhibit the enzyme poly(ADP-ribose) polymerase (PARP). Specific inhibition of PARP-1 can induce synthetic lethality in irradiated cancer cells while theoretically leaving normal tissue unaffected. We recently demonstrated in a cell survival assay that lymphoblastoid cells with mono-allelic mutations of BRCA1 were hypersensitive to gamma radiation in the presence of the PARP-1 inhibitor Olaparib compared to normal cells and mono-allelic BRCA2 cells. To determine if the enhanced radiation sensitivity was due to a persistence of DNA strand breaks, we performed γ-H2AX foci analysis in cells derived from two normal individuals, three heterozygous BRCA1 and three heterozygous BRCA2 cell lines. Cells were exposed to 2 Gy gamma radiation in the presence or absence of 5 μM Olaparib. Using immunofluorescence and imaging flow cytometry, foci were measured in untreated cells and at 0.5, 3, 5 and 24 hours post-irradiation. In all lymphoblastoid cells treated with 2 Gy gamma radiation, there was a predictable induction of DNA strand breaks, with a modest but significant retention of foci over 24 hours in irradiated cells treated with Olaparib (ANOVA P < 0.05). However, in mono-allelic BRCA1 cells, there was a failure to fully repair DNA double-strand breaks (DSB) in the presence of Olaparib, evidenced by a significant retention of foci at 24 hours’ post irradiation (t-Test P These data show that the cellular hypersensitivity of mono-allelic BRCA1 lymphoblastoid cells to gamma radiation in the presence of the Olaparib is due to the retention of DNA DSB. These data may indicate that patients with inherited mutations in the BRCA1 gene treated with radiotherapy and PARP-1 inhibitors may experience elevated radiation-associated normal tissue toxicity.
文摘【目的】评价不同吉富罗非鱼群体的遗传多样性,筛选出鉴别不同群体的分子标记,为吉富罗非鱼种质资源保护及其新品种选育提供理论依据。【方法】对48尾来自两个不同群体的吉富罗非鱼进行尾静脉采血,抽提其基因组DNA,应用微卫星标记技术判定其等位基因和基因型,然后采用Gen Al Ex 6.2、Cervus 3.0和Populations软件进行数据分析,计算有效等位基因数（Ne）等群体遗传多样性相关参数,对两个吉富罗非鱼群体进行遗传差异分析。【结果】从50对微卫星引物中筛选出23对扩增产物稳定、条带清晰、特异性好的引物,扩增出的DNA片段大小在110~388 bp。利用23个微卫星位点,从两个吉富罗非鱼群体中共检测到89个等位基因和163种基因型,平均每个位点的等位基因数（Na）3.8个、基因型7.1种。两个吉富罗非鱼群体的平均观察杂合度（Ho）分别为0.6383和0.5957,平均期望杂合度（He）分别为0.5759和0.5559;23个位点在两个群体中平均多态信息含量（PIC）分别为0.5131和0.4942,平均固定系数（FIS）分别为-0.1184和-0.0718;两个群体间的遗传距离（DA）为0.1287,平均遗传分化系数（FST）为0.135。UNH911、GM141、GM287、GM134等4个位点在两个群体中扩增的条带存在明显差异。【结论】两个吉富罗非鱼群体遗传多样性水平较高,均存在杂合子过剩现象,群体间遗传分化程度中等,具有较强的环境适应能力,且选育空间大。UNH911、GM141、GM287、GM134等4个微卫星位点可作为鉴别两个吉富罗非鱼群体的分子标记,也可用于分子标记辅助育种研究。
