Predictive value of sCTLA-4 and RAD51C proteins for recurrence after interventional therapy for cervical cancer patients / 中华内分泌外科杂志

Objective:To analyze the predictive value of soluble cytotoxic T lymphocyte-associated antigen 4 (sCTLA-4) and RAD51 paralogous gene C (RAD51C) protein in the recurrence of cervical cancer patients after interventional therapy.Methods:A total of 107 patients with cervical cancer who underwent interventional surgery in our hospital from May. 2015 to Apr. 2019 were selected as the research group. postoperative recurrence were recorded. Another 107 patients with benign cervical disease during the same period were selected as the control group. The protein expressions of sCTLA-4 and RAD51C were compared between the two groups and patients with or without recurrence. Logistic regression was used to analyze the influencing factors of postoperative recurrence of cervical cancer patients, and a nomogram model of postoperative recurrence of cervical cancer patients was constructed and verified by calibration curve. The postoperative recurrence rate of cervical cancer patients with different sCTLA-4 and RAD51C protein expressions was compared.Results:The level of sCTLA-4 and the high expression rate of RAD51C protein in the study group were higher than those in the control group ( P<0.05). High-risk human papillomavirus positive, vascular infiltration, interstitial infiltration ≥1/2, paracterine infiltration, high expression of RAD51C protein and high SCTLA-4 level were independent risk factors for postoperative recurrence of cervical cancer ( P<0.05). High-risk human papillomavirus, vascular invasion, interstitial invasion, parametrial invasion, RAD51C protein and sCTLA-4 levels were used to construct a nomogram prediction model for postoperative recurrence of cervical cancer patients. The consistency indices were 0.610 (95% CI: 0.511-0.702), 0.616 (95% CI: 0.517-0.708), 0.640 (95% CI: 0.541-0.730), 0.609 (95% CI: 0.510-0.702), 0.728 (95% CI ranged from 0.633 to 0.809), 0.817 (95% CI ranged from 0.731 to 0.885), and the calibration curve validation showed high consistency. The net benefit rate of combined detection of sCTLA-4 and RAD51C proteins was greater than that of single detection. Conclusions:sCTLA-4 and RAD51C proteins are highly expressed in cervical cancer patients, and the high expression of both indicates that cervical cancer patients have a higher risk of recurrence after surgery. Clinically, the detection of sCTLA-4 and RAD51C protein expression can be used to screen patients with high recurrence risk.

Development of a tau-V337M mouse model using CRISPR/Cas9 system and enhanced ssODN-mediated recombination / 生物工程学报

The generation of a tau-V337M point mutation mouse model using gene editing technology can provide an animal model with fast disease progression and more severe symptoms, which facilitate the study of pathogenesis and treatment of Alzheimer's disease (AD). In this study, single guide RNAs (sgRNA) and single-stranded oligonucleotides (ssODN) were designed and synthesized in vitro. The mixture of sgRNA, Cas9 protein and ssODN was microinjected into the zygotes of C57BL/6J mice. After DNA cutting and recombination, the site homologous to human 337 valine (GTG) in exon 11 was mutated into methionine (ATG). In order to improve the efficiency of recombination, a Rad51 protein was added. The female mice mated with the nonvasectomy male mice were used as the surrogates. Subsequently, the 2-cell stage gene edited embryos were transferred into the unilateral oviduct, and the F0 tau-V337M mutation mice were obtained. Higher mutation efficiency could be obtained by adding Rad51 protein. The F0 tau-V337M point mutation mice can pass the mutation on to the F1 generation mice. In conclusion, this study successfully established the first tau-V337M mutation mouse by using Cas9, ssODN and Rad51. These results provide a new method for developing AD mice model which can be used in further research on the pathogenesis and treatment of AD.

MiR-375-3p enhanced radiosensitivity of colorectal cancer cells by inhibiting homologous recombination repair of DSBs / 中华放射医学与防护杂志

Objective:To investigate the effect of miR-375-3p on DNA damage repair and radioresistance of colorectal cancer cells.Methods:After overexpression of miR-375-3p in HCT116 and HT29, cell proliferation ability was detected by CCK-8 assay, clone formation ability was detected by clone formation assay, apoptosis was detected by Annexin V-FITC/PI double staining method and cell cycle distribution was detected by flow cytometry, and the formation of γ-H2AX foci were used to analyze homologous recombination (HR) repair efficiency. Bioinformatics was used to predict the downstream target genes of miR-375-3p in the HR repair pathway. A dual luciferase reporter gene assay was used to validate the regulation effect of miR-375-3p on Rad51 gene. The expression of miR-375-3p in HCT116 cells irradiated with 60Co γ-rays at 2 and 6 Gy was measured by RT-qPCR. The inhibition effect of miR-375-3p on the radiosensitivity of HCT116 cells was analyzed after irradiation with different doses of 0, 1, 2, 4 and 6 Gy. Results:Overexpression of miR-375-3p inhibited the proliferation and colony formation ability, induced G1 phase cycle arrest and cell apoptosis of colorectal cancer cells, enhanced DSBs formation, inhibited Rad51 expression, and significantly decreased HR repair efficiency ( t = 10.055, P < 0.05). Dual luciferase reporter gene assay demonstrated that miR-375-3p bound to Rad51 3′UTR region ( t = 5.013, P< 0.05). In addition, irradiation increased miR-375-3p expression, and inhibition of miR-375-3p expression reduced radiosensitivity of colorectal cancer cells ( t=6.460, 5.619, 10.150, P<0.05). Conclusions:miR-375-3p inhibited the homologous recombination repair efficiency of DSBs and enhanced the radiosensitivity of colorectal cancer cells.

Association of XRCC1 Arg399Gln and RAD51 135 G>C polymorphisms and epidemiologic risk factors with colorectal cancer among selected Filipinos

@#<p style="text-align: justify;"><strong>Objectives.</strong> Several studies have demonstrated that genetic variants of certain DNA repair genes such as the RAD51 and XRCC1 increase cancer risk substantially. The results were also observed to be race- and tumor site specific. Hence, this study aimed to determine the possible association of XRCC1 Arg399Gln and RAD51 135G>C polymorphisms combined with risk factors of colorectal cancer (CRC) among selected Filipinos.</p><p style="text-align: justify;"><strong>Methods.</strong> Genomic DNA isolated from peripheral blood samples of histologically confirmed CRC patients (n=70) and their age- and sex-matched clinically healthy controls (n=70) were analyzed for polymorphisms of XRCC1 and RAD51 genes by polymerase chain reaction.</p><p style="text-align: justify;"><strong>Results.</strong> The genotypic distribution pattern of RAD51 135G>C (p?0.05) was not significantly different between the CRC cases and controls. Significantly higher incidence (p=0.016) of the XRCC1 GG genotype was noted among the cases (n=34, 49%) compared with controls (n= 20, 29%). Individuals carrying the XRCC1 AG genotype have a lower risk of developing CRC (OR=0.42, 95% CI=0.21-0.85) than the XRCC1 GG genotype. XRCC1 AG genotype combined with alcohol drinking, smoking, or family history of cancer also showed a lower risk of developing CRC. There was no significant association between the genetic variants of RAD51 135G>C and CRC risk. Carriers of both XRCC1  GG and RAD51 CC genotypes showed a 5x higher risk (OR=5.02; 95%; CI=1.0429-24.1283) compared to those carrying other genotype combinations (p=0.028).</p><p style="text-align: justify;"><strong>Conclusions. </strong>XRCC1 Arg399Gln but not RAD51 135G>C may be associated with CRC development among Filipinos. Individuals who drink alcohol, smoke tobacco and have a family history of cancer have a lower risk of developing CRC when they are also carrying the XRCC1 AG genotype. The findings may have significant impli cations in designing personalized methods for screening, diagnosing, and treating CRC.</p>

Berberine enhances the radiosensitivity of osteosarcoma by targeting Rad51 and epithelial–mesenchymal transition

Objective: Osteosarcoma is a malignant bone tumor and is generally treated with radiotherapy combined with radiosensitizers. The aim of the present study was to investigate the radiosensitization effects of berberine on osteosarcoma cells and the role of Rad51 in radiosensitivity by berberine. Materials and Methods: Cells from the human osteosarcoma cell line MG-63 were exposed to γ-ray irradiation (0, 2, 4, 6, and 8 Gy) and berberine (20 μM). Radiosensitivity was evaluated by determining cell viability using an MTT assay. Flow cytometry was used to determine cell cycle and apoptosis. Real-time PCR and western blot were performed to analyze the mRNA and protein expressions of Rad51. The protein levels of E-cadherin and vimentin were also measured to evaluate the epithelial–mesenchymal transition (EMT) process. Tumor invasion was determined by the Boyden chamber assay. Results: Berberine exacerbated the decline in viability of MG-63 cells exposed to γ-rays irradiation at various concentrations (25, 50, 75, and 100 μmol/L) and induced cell cycle arrest in the G2/M phase as well as apoptosis. The mRNA and protein expressions of Rad51 were significantly decreased by berberine in MG-63 cells. Inhibition of Rad51 by B02 enhanced the radiosensitivity of MG-63 cells. Berberine inhibited their invasive capability as well as increased E-cadherin and decreased vimentin protein levels; this indicated that berberine suppressed the EMT process in MG-63 cells exposed to γ-rays irradiation. Conclusion: Berberine enhances the radiosensitivity of MG-63 osteosarcoma cells. Rad51 is a potential target of berberine in the radiosensitization of osteosarcoma

Expressions of HELQ and RAD51C in endometrial stromal sarcoma and their clinical significance / 南方医科大学学报

OBJECTIVE@#To observe the expression of HELQ and RAD51C in normal endometrial and endometrial stromal sarcoma (ESS) and analyze their correlation with the clinical features of the patients.@*METHODS@#The expressions of HELQ and RAD51C proteins were detected by immunohistochemical staining in normal endometrial tissues (14 cases) and tumor tissues from patients with ESS (37 cases) treated in Hunan Provincial Cancer Hospital from January, 2013 to December, 2016. The correlations of the expressions of the two proteins with the patients'age, FIGO staging, tissue type, tumor size, and lymph node metastasis were analyzed.@*RESULTS@#Immunohistochemical staining showed that the expressions of HELQ and RAD51C were both decreased in ESS patients compared with the normal group, and there was a positive correlation between HELQ and RAD51C expression ( < 0.05). HELQ expression in ESS was correlated with the tumor size and type. The expressions of HELQ and RAD51C were not correlated with the patients' age, FIGO stage and status of lymph node metastasis ( > 0.05).@*CONCLUSIONS@#Homologous recombination- directed DNA repair involving HELQ and RAD51C may participate in the occurrence and progression of ESS.

Study on RAD51 Gene Regulatory Mechanism of Apigenin Affecting Cisplatin Sensitivity to NSCLC A 549 Cells / 中国药房

OBJECTIVE：To study the effects and mechanism o f apigenin on cisplatin sensitivity of NSCLC A 549 cells by regulating RAD51 gene. METHODS ：Human lung cancer cisplatin-resistant cells A 549/DDP were selected and divided into control group（blank culture medium ），cisplatin group （5 g/L），apigenin low-dose and high-dose groups （10，20 μmol/L）. MTT assay was used to detect the growth of A 549/DDP cells ，while the Annexin Ⅴ/PI double staining combined with flow cytometry were used to detect the apoptosis. A 549/DDP cells were collected and divided into cisplatin alone group （1，2，4，8，16 μg/mL）， apigenin combination group （10 μmol/L，based on cisplatin ）. MTT method was used to determine and calculate inhibitory rate of cell proliferation. IC 50 values of drugs were calculated by regression model ，and reversion index of apigenin was calculated. 18 nude mice were randomly divided into control group ，cisplatin alone group and apigenin combination group ，with 6 mice in each group. After A 549/DDP cells were inoculated to form the transplanted tumor ，normal saline ，cisplatin（2 mg/kg，once every other day ）， cisplatin（the same dosage and usage ）+apigenin solution （30 mg/kg，once a day ）were injected intraperitoneally respectively. After 18 days of continuous administration ，the body weight of mice and the mass of the transplanted tumor were detected and the tumor inhibition rate was calculated. Human lung cancer cells A 549 and A 549/DDP were collected and divided into normal group （A549 cells），control group （A549/DDP cells ），cisplatin group （5 g/L，A549/DDP cells ）and apigenin low-dose and high-dose groups （10，20 μmol/L，A549/DDP cells ），respectively. mRNA and protein expression of RAD51 were detected by real-time fluorescence quantitative PCR and Western blotting assay. RESULTS ： Δ 基金项目：四川省教育厅（自筹经费）科研项目（No.12ZB227） ＊讲师，硕士。研究方向：肿瘤病理。E-mail：molin212@163.com Compared with control group ，the cell growth of apigenin # 通信作者：副教授，硕士生导师，硕士。研究方向：肿瘤病理。 low-dose and high-dose groups were decreased significantly ， E-mail：xinrongH292@163.com apoptosis rates of them w ere increased significantly and higher ·708· China Pharmacy 2020Vol. 31 No. 6 中国药房 2020年第31卷第6期 than those of cisplat in group （P＜0.05 or P＜0.01）. After combined with apigenin ，proliferation inhibition rate of A 549/DDP cells was increased significantly ，compared with cisplatin alone group with the same concentration （P＜0.05）. The IC 50 in the apigenin combination group was （5.81±0.47）μg/mL，significantly lower than （14.44±0.52）μg/mL in cisplatin alone group（P＜0.05），and reversal index of apigenin was 2.49. The results of nude mice tumor inhibition experiment showed that after combined with apigenin，tumor inhibition rate of A 549/DDP bearing nude mice was 68.72％，significantly lower than 33.82％ in cisplatin alone group. Compared with A 549 cells of normal group ，relative expression of RAD51 mRNA and protein were increased significantly in A549/DDP cells of control group （P＜0.05）. Compared with A 549/DDP cells of control group ，relative expression of RAD51 mRNA and protein in A 549/DDP cells were decreased significantly in apigenin low-dose and high-dose groups （P＜0.05）. Compared with cisplatin group ，relative expression of RAD51 mRNA and protein in A 549/DDP cells of apigenin low-dose and high-dose group were decreased significantly （P＜0.05）. CONCLUSIONS ：Apigenin can effectively reverse drug resistance of cisplatin-resistant A 549/DDP cells in human lung cancer. The mechanism may be related to the reduction of RAD51 gene transcription and protein expression.

Effect of ionizing radiation on DNA damage repair in hela cells silencing ATRX / 吉林大学学报(医学版)

Objective: To silence α-thalassemia/mental retardation syndrome XTinked gene (ATRX) in the cervical cancer HeLa cells, to detect the effect of ionizing radiation on the protein expressions of ATRX, γH2AX, Rad51 and γH2AX, Rad51 foci, and to explore the role of ATRX in DNA damage repair of the HeLa cells after irradiation. Methods: Three ATRX-shRNA and negative Control-shRNA lentiviral vectors were transfected into the 293T cells, and the Antiviruses were collected to infect the HeLa cells; puromycin was used to obtain the HeLa cells stably silencing ATRX named shAi-HeLa, shA2-HeLa, shA3-HeLa, and shCon-HeLa; the silencing efficiency was detected by Western blotting method. After ionizing radiation, the expressions of ATRX, γH2AX, and Rad51 proteins were measured by Western blotting method, and the numbers of γH2AX and Rad51 foci in shCon-HeLa and shAi-HeLa groups were observed and counted by immunofluorescence technique. Results: The ATRX protein expressed in shCon-HeLa cells, but did not express in shA1-HeLa, shA2-HeLa, and shA3-HeLa cells; it indicated that the silencing efficiency was higher. At 1, 6, and 24 h after 2 and 8 Gy irradiation, the ATRX protein expression levels in shCon-HeLa group were increased gradually; it was most at 24 h, and the ATRX was highly expressed at 1, 6, and 24 h after 8 Gy irradiation. Compared with shCon-HeLa group, at 0-6 h after 4 Gy irradiation, the number of γH2AX foci in shA1-HeLa group was significantly increased at 1 h (P<0. 05), then was gradually decreased, but the number of γH2AX foci in shA1-HeLa group was still higher at 6 h (P<0. 01). The number of Rad51 foci was consistent with the changes of γH2AX focus number. Compared with shCon-HeLa group, the number of Rad51 foci was significantly increased at 1 h (P<0. 05), and the number in shA1-HeLa group was still higher at 6 h (P<0.01). At 0-16 h after 4 Gy irradiation, compared with shCon-HeLa, the expression amounts of γH2AX and Rad51 proteins in shAi-HeLa group were increased. Conclusion: The HeLa cell models silencing ATRX are successfully obtained; ionizing radiation can cause the increase of ATRX expression level; the focus number and the protein expression amounts of γH2AX and Rad51 in HeLa cells silencing ATRX are higher than those in control group, which indicates that ATRX involves in the repair of radiation-induced DNA damage.

FoxM1 inhibitor sensitize resistant osteosarcoma cells to cisplatin by down-regulation of Rad51 / 临床与实验病理学杂志

Purpose To investigate whether FoxM1 participate in inhibitory effect of cisplatin (CDP) in resistant osteosarcoma cell lines by down-regulation of Rad51.Methods The resistant osteosarcoma cell lines were induced by gradually increasing dose intermittent action,and were named MG-63/R and HOS-MNNG/R respectively.The mRNA and protein level of FoxMl and Rad51 were detected by qRT-PCR and Western blot analysis in resistant cells and parental cells.The mRNA and protein level of FoxM1 and Rad51 were detected by qRT-PCR and Western blot analysis in resistant cells after treatment of 4 μmol/L Thiostrepton.The effect of single or combined treated of 4 tμmol/L Thiostrepton or 2 tμg/mL CDP on the rate of cell proliferation in resistant cells was examed by cell counting.Results Resistant osteosarcoma cell lines MG-63/R and HOSMNNG/R were established and stablely growthed in the concentration of 2 μg/mL CDP,and the resistance index was 30.52 and 37.87 respectively (severe CDP resistance).The mRNA and protein level of FoxM1 and Rad51 were significantly increaced in resistant cells compared with parental cells.The proliferation rate of resistant cells in conbination of 4 μmol/L Thiostrepton and 2 μg/mL CDP treated group was significantly lower than these two drugs single treated group.The level of mRNA and protein of FoxM1 and Rad51 were significantly decreased after 4 μmol/L Thiostrepton treatment in CDP resistant cells.Conclusion The results suggest that FoxM1 and Rad51 may participate in the resistant osteosarcoma cells to CDP.FoxM1 inhibitor Thiostrepton may strengthen the inhibitory effect of CDP in the resistant cells by down-regulation of Rad51.

Lethal effect of RI-1 on MSH2-deficient colorectal cancer cells / 基础医学与临床

Objective To explore the lethal action and possible mechanism of RI-1, a RAD51 inhibitor, on MSH2 deficient colorectal cancer cells.Methods The expression of MSH2 protein level was assessed by Western blot, and the sensibility of human colorectal cancer cells to RI-1 (10, 20, 30, 40 and 50 μmol/L)was measured by MTT method.Lentivirus vectors MSH2-shRNA and Neg-shRNA (negative control) were constructed and transfected into HT29 cell.Apoptosis and DNA damage of cells treated with RI-1(40 μmol/L)were detected by flow cytometry and Single cell gel electrophoresis respectively.In addition, the formation of γ-H2AX foci was analyzed by immunofluorescence.Results Compared with control, MSH2-deficient HCT8 cells had obviously apoptosis(P<0.01);in HCT8 and HT29 Shmsh2 cells, tail DNA%, tail length, tail moment and olive tail moment were markedly increased(P<0.05),and the number of γ-H2AX focus were increased(P<0.01).Conclusions RAD51 inhibitor RI-1 selectively kills MSH2 deficient colorectal cancer cells by increasing DNA damage.

Valor prognóstico de polimorfismos nos genes de reparo do DNA XRCC3 E RAD51 em pacientes com carcinoma epidermóide oral e de orofaringe / Prognostic value of polymorphisms of DNA repair gene RAD51 XRCC3 and in patients with oral squamous cell carcinoma and oropharyngeal

Falhas nos genes responsáveis por reparos no DNA podem influenciar no surgimento de câncer ou afetar a resposta aos tratamentos. Estudos têm demonstrado que a variação na capacidade de reparo do DNA pode ser resultado de polimorfismos funcionais nestes genes, e alguns destes experimentos sugerem que a presença de polimorfismos de nucleotídeos simples (SNPs), em genes de reparo, está relacionada ao desenvolvimento e resposta ao tratamento de vários cânceres, incluindo o Carcinoma Epidermoide Oral (CEO) e o Carcinoma Epidermoide de Orofaringe (CEOR). Nesta pesquisa avaliou-se a frequência de três SNPs em dois genes de reparo do DNA RAD51 172G>T (c.-61 G>T, rs1801321), RAD51 135G>C (c.-98 G>C, rs1801320) e XRCC3 T241M (c. 722 C>T, rs861539) em indivíduos saudáveis (n=130) e indivíduos com CEO e CEOR (n=126) e investigou-se possíveis relações de tais achados com os desfechos clínicos: resposta tumoral ao tratamento com radioterapia e quimioterapia, recidiva, e sobrevida global. Constatou-se frequência alélica e genotípica em equilíbrio. A presença dos SNPs analisados não revelou ser um fator de risco para o desenvolvimento de CEO ou CEOR; contudo, quando associado ao hábito de fumar ou beber, aumentou o risco de desenvolver o câncer de três a cento e cinquenta vezes (p<000,1). A resposta tumoral ao tratamento de radioterapia e quimioterapia foi semelhante nos pacientes com ou sem SNPs. Nenhum polimorfismo demonstrou significância estatística em relação à sobrevida livre de recidiva ou sobrevida global. Os genótipos AA e AC do SNP rs861539 no gene XRCC3, os genótipos CC e CG do SNP rs1801320 e GG e GT do SNP 1801321 no gene RAD51, aumentam o risco do desenvolvimento de carcinoma epidermoide oral e de orofaringe, quando associados ao hábito de beber ou fumar. Os polimorfismos estudados nos genes XRCC3 e RAD51 não estão associados à resposta à radioterapia, sobrevida livre de recidiva ou sobrevida global

Faults in the genes responsible for repairs to the DNA can influence the onset of cancer or affect the response to treatment. This research evaluated the frequency of three single nucleotide polymorphisms (SNPs) in two repair genes DNA RAD51 172g> T (rs1801321), RAD51 135G> C (rs1801320) and XRCC3 T241M (rs861539) in individuals without cancer (n = 130) and patients with oral squamous cell carcinoma (OSC) and carcinoma oropharyngeal squamous (ORSC) (n = 126) and investigated possible relationships of these findings with clinical and pathological data and clinical outcomes: tumor response to radiotherapy and chemotherapy, disease-free survival, and overall survival. It was found that the allele and genotype frequencies were in equilibrium Hard-Weinberg equilibrium. The presence of at least one polymorphic allele in XRCC3 (rs861539) gene is associated with histological grade (WHO) higher (p = 0.007). We observed a higher recurrence rate trend (p = 0.08) and more advanced stage (p = 0.08) in the group that had at least one polymorphic allele of RAD51 gene (rs1801321). The presence of the analyzed SNPs not proved to be a risk factor for the development of CEO or CEOR; however, when combined with smoking or drinking, increased the risk of developing cancer from three to one hundred and fifty times. The tumor response to radiotherapy and chemotherapy was similar in patients with and without SNPs. No polymorphism showed statistical significance in relation to recurrence-free survival or overall survival. We conclude that the presence of at least one polymorphic allele of the SNPs rs861539 in XRCC3 gene, rs1801320 and rs1801321 in the RAD51 gene increase the risk of development of OSC and ORSC, when associated with the habit of drinking or smoking. Polymorphisms studied in XRCC3 and RAD51 genes are not associated with response to radiation therapy, relapse-free survival or overall survival

Research progress on Rad51C in DNA damage repair / 中国肿瘤临床

Cytotoxic substances and ionizing radiation can easily induce DNA damage, and double strand breaks (DSBs) are the main form of DNA damage. DNA damage can activate intracellular DNA damage responses and further induce related biological effects, such as DNA damage repair and cell cycle arrest. Homologous recombination (HR) is the primary DSB repair mechanism in eukaryotes. Abnormal expression of Rad51C, which is a key factor in the HR pathway, may result in DNA repair disorder, genomic instability, and eventually lead to tumor formation. In recent studies, researchers considered Rad51C as a potential target for cancer treatment. We reviewed the research progress on Rad51C in DNA damage repair and radiotherapy.

Mutaciones del gen RAD51 en el cáncer familiar de ovario: revisión de la literatura / RAD51 gene mutations in familial ovarian cancer: literature review

ANTECEDENTES: En los últimos 15 años, el carcinoma familiar de ovario, ha sido atribuido en su mayoría a mutaciones en BRCA 1 y 2. Sin embargo, aproximadamente el 25% de los nuevos casos se asocian a mutaciones aisladas de genes implicados en el mecanismo de reparación del ADN por recombinación homóloga. Mutaciones monoalélicas de RAD51 han sido identificadas en pacientes con historia de carcinoma mama y ovario, tamizaje negativo para BRCA 1 y 2, y por lo menos con un caso de carcinoma de ovario en el linaje. OBJETIVO: Describir las mutaciones en el complejo RAD51 con el fin de identificar su papel en el cáncer de ovario familiar. MÉTODO: Se realizó una búsqueda de la literatura en bases de datos de los últimos 10 años con los siguientes términos MeSH: "RAD51", "ovarian cancer" "ovarian neoplasm", "family ovarian cancer". RESULTADOS: Se encontró una prevalencia de la mutación en genes del complejo RAD51 que varía entre 0,2% y 2,5%, según la etnia estudiada, siendo una de las causas de tumores serosos de ovario de alto grado en mujeres entre los 57 y 60 años. CONCLUSIÓN: Mutaciones de RAD51 en pacientes negativas para mutaciones de BRCA 1 y 2, se asocian al síndrome familiar mama-ovario, con un aumento del riesgo para carcinoma de ovario, pero sin modificaciones para el carcinoma de mama.

BACKGROUND: In the last fifteen years, familiar ovarian carcinoma has been related to BRCA 1 and 2 mutations. However, 25% of new cases of ovarian neoplasm are explained by isolated genes involved in the mechanism of homologous recombination. Patients with family history of ovarian and breast carcinoma, negative for BRCA mutations and at least with one case of invasive ovarian carcinoma have been identify with monoallelic mutations in RAD51. OBJECTIVE: To describe mutations on RAD51 complex, in order to identify its role in familiar ovarian cancer. METHODOLOGY: A systematic review of the literature of the last ten years involving the main data bases and using the following MeSH terms: "RAD51", "ovarian cancer", "ovarian neoplasm", "family ovarian cancer". RESULTS: Prevalence reported for RAD51 mutation is between 0.2 and 2.5%, associated with the ethnicity of the population involved. Also is considered a cause for high grade serous ovarian carcinoma in women between 57 and 60 years old. RAD51C and RAD51D germ line mutations are related to ovarian-breast hereditary syndrome, in negative population for BRCA 1 and 2 mutations. CONCLUSION: Patients with RAD51 mutations, negative for BRCA mutation are associated with ovarian-breast cancer syndrome increasing the risk just for ovarian cancer.

BMS-345541 regulates repair of DNA double-strand breaks induced by VP-16 in acute myeloid leukemia cells / 中国药理学通报

Aim To investigate the effect of BMS- 345541 on the repair of DNA DSBs induced by VP-16 in AML cells and its possible mechanism. Methods The effects of BMS-345541 on the sensitivity of AML cells to VP-16 were determined by MTT. Flow cytome-try ( FCM) was applied to test the level of DNA dam-age, cell cycle progression and apoptosis in AML cells. High content analysis ( HCA) was used to verify the amount ofγ-H2AX,p-ATM,RAD51 in AML cells. Results BMS-345541 could significantly inhibit the proliferation of AML cells induced by VP-16 . BMS- ＜br> 345541 increased the amount of RAD51 foci and p-ATM foci in AML cells treated with VP-16 after 6 hours , which led to increased numbers of cells in the G2/M phases of the cell cycle,then induced apoptotic cell death. Conclusion BMS-345541 sensitizes AML cells to VP-16 via selective inhibition of homologous recombinational repair of DNA double-strand breaks.

Relationship between RAD51 Polymorphism and Therapeutic Efficacy of Cisplatin Chemotherapy in Cervical Cancer Patients / 中国药房

OBJECTIVE:To observe the effects of RAD51 gene polymorphism on cancer prognosis and its relationship with therapeutic efficacy of cisplatin chemotherapy in patients with cervical cancer. METHODS:193 cervical cancer patients were selected and genotyped by TaqmanTM genotyping method. Therapeutic efficacy and survival period were observed in cisplatin chemotherapy combined with radiotherapy. RESULTS:The mean survival rate and therapeutic efficacy was significantly correlated with RAD51 genotype. The patients carrying the T gene had better response to drugs,compared to patients with type GG (P<0.05),and the average survival rate significantly increased(P<0.05). CONCLUSIONS:Genetic variation in RAD51 have obvious influence on the prognosis of cervical cancer chemotherapy. Therefore,RAD51 G172T genotypes give effective prognosis information about cervical cancer patients who received cisplatin chemotherapy.

Relationship between RAD51 135G ＞ C polymorphism and prognosis in triple-negative breast cancer patients / 中华内分泌外科杂志

Objective To investigate the relationship between RAD51 135G ＞ C polymorphism and prognosis in triple-negative breast cancer patients by retrospective analysis.Methods The clinical data of 62 triplenegative breast cancer patients were collected.The 62 cases underwent standard chemotherapy and radiotherapy after tumor resection from Jan.2004 to Dec.2010 in Affiliated Cancer Hospital of Zhengzhou University.RAD51 135G ＞ C polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP) technology.The survival curve about progress free and overall survival time were then made.Results The median progress free and overall survival time in triple-negative breast cancer patients with or with-out RAD51 135G ＞ C polymorphism were(77.00 ±5.55)and(89.00 ± 10.40) months vs(99.00 ±4.26)and (103.00 ±4.30) months.The difference had statistical significance(P =0.039 and 0.015 respectively).Conclusion RAD51 135G ＞ C polymorphism is related with prognosis of triple-negative breast cancer patients,which might be a prognostic factor for breast cancer.

Effect of EGFR mutation on radiation-induced DNA repair in pulmonary adenocarcinoma cells / 中华放射医学与防护杂志

Objective To observe the effect of EGFR mutation on radiation induced DNA repair in pulmonary adenocarcinoma ceils.Methods A549 cells with wild-type EGFR and H1975 cells with mutated-type of EGFR were irradiated by 4 Gy of 6 MV X-rays.After irradiation,the formation of nuclear γ-H2AX foci was assayed with immunostaining method,the level of DNA-PKcs-EGFR interaction was detected with coimmunoprecipitation,and nuclear RAD51 expression and EGFR nuclear translocation were detected using Western blot.Results DNA repair in the H1975 cells was significantly lower than that in A549 cells.In the irradiated H1975 cells,there was no EGFR translocation with further nuclear DNA-PKcs binding,and the expression of nucleus RAD51 was not altered.But in the irradiated A549 cells,EGFRDNA-PKcs interaction and nucleus RAD51 were increased.Conclusions Lung adenocarcinoma cell line with mutations in the tyrosine kinase domain (TKD) of EGFR exhibits a high radiosensitivity due to the reduction of the non-homologous end-joining (NHEJ) and homologous recombination (HR) DNA DSB repair kinetics.

Correlation of RAD51 and radiosensitization of methotrexate / 中华放射医学与防护杂志

Objective To evaluate the correlation between homologous recombination repair protein RAD51 and methotrexate-enhanced radiosensitivity.Methods Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate.Colony formation assay was used to test the survival fraction of HOS cells exposed to γ-rays and methotrexate.Results Methotrexate inhibited both protein and RNA expressions of RAD51,and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression.Moreover,transfection of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays.The sensitizer enhancerment ratios after irradiation in combination with methotrexate were 1.51 and 0.99,respectively.Methotrenate was a preferred radiosensitizer to HOS cell.Conclusions RAD51 might be involved in the methotrexate-enhanced radiosensitivity.

Influence of tumor suppressor gene PTEN expression on biological behaviors of radiation-induced mouse thymoma cells / 第二军医大学学报

Objective: To investigate the expression of tumor suppressor gene PTEN in the radiation-induced mouse thymoma cells, and to observe the inhibitory effect of exogenous PTEN transfection on the in vitro proliferation and in vivo tumor forming ability of radiation-induced thymoma. Methods: Immunohistochemistry SP and Western blotting assay were used to examine the expression of PTEN, γ-H2AX, and Rad51 protein in radiation-induced mice thymoma and normal thymus tissues. RT-PCR assay was conducted to examine the PTEN gene loss. Exogenous PTEN gene was transferred into mouse thymoma cells and its inhibitory effects on cell proliferation and tumor-forming ability were observed. Results: The positive rate of PTEN protein expression was 22.73% (5/22) in radiation-induced thymoma tissue, significantly lower than that in the normal thymus tissue (P < 0.01). Western blotting assay showed that the expression of PTEN protein in thymoma was markedly lower than that in the normal thymus tissue (P<0.01). RT-PCR found that in tumor tissue there was high-frequency of PTEN gene loss. Exogenous PTEN expression in thymoma significantly inhibited the cell proliferation and the tumor-forming ability (P<0.01). The expression of γ-H2AX protein in the thymoma tissue was significantly higher than that in the normal thymus tissue; the expression of Rad51 protein was significantly lower than that in the normal tissue. Conclusion: Loss of PTEN gene may contribute to radiation-induced thymoma via influencing the Rad51-mediated DNA repair pathway. Exogenous PTEN gene transfer can inhibit the in vitro proliferation of thymoma cells, which may contribute to the treatment and prevention of radiation-induced tumor.

Expression of RAD51 and MAX in pancreatic cancer rats / 中南大学学报(医学版)

Objective To establish a model of pancreatic cancer induced by 7,12-dimethylbenzathracene (DMBA) in SD rats, and to detect the expression levels of RAD51 and Myc-associated factor X (MAX) and their effect on carcinogenesis of rat pancreas. Methods Ninety SD rats were randomly divided into 3 groups: a model group, an intervention group, and a control group. DMBA was directly implanted into the parenchyma of rat pancreas (the model group and the intervention group). Rats in the intervention group were treated with 1 mL trichostatin A (TSA) saline solution (1 μg/mL) via ip weekly. Rats within 3～5 months in the model group and the intervention group were executed and observed by macrograph and under microscope. Meanwhile, the rats in the control group were executed at 5th month. The EnVision~(TM) immunohistochemistry to assay the expression levels of RAD51 and MAX was used in conventional paraffin-embedded sections from the above pancreatic specimens.Results The incidence of pancreatic cancer in the model group within 3-5 months was 48.7% (18/37), including 17 ductal adenocarcinomas and 1 fibrosarcoma. The incidence of pancreatic cancer in the intervention group within 3-5 months was 33.3%(12/36), including 11 ductal adenocarcinomas and 1 fibrosarcoma. The maximal diameter of mass in the model group was significantly higher than that in the intervention group (P＜0.05). No pathological changes were found in pancreas of the control group and other extra-pancreatic main organs of the model group and the intervention group (such as the liver, biliary tract, gastrointestine tract, kidney, and lung). The positive rate of RAD51 was significantly higher in ductal adenocarcinoma in the model group, the intervention group, and the model group +the intervention group than those in corresponding groups of non-cancerous pancreatic tissues (P＜0.01), but the positive rate of MAX expression was opposite to RAD51 expression(P＜0.01). The positive tissues of RAD51 expression and/or negative tissues of MAX expression in non-cancerous tissues showed atypical-hyperplasia of ductal epitheli. Pacncreas of the control group showed the negative expression of RAD51 and positive expression of MAX. Two cases of fibrosarcoma showed the negative expression of RAD51 and MAX.Conclusion DMBA directly implanted into the parenchyma of pancreas can obtain an ideal pancreatic cancer model with high incidence in a short time. The TSA might have an inhibitive effect on carcinogenesis and growth of rat pancreas. The over-expression of RAD51 and/or lose-expression might have important effect on carcinogenesis induced DMBA in rat pancreas.