The genomic instability may lead to an initiation of cancer in many organisms. Homologous recombination repair (HRR) is vital in maintaining cellular genomic stability. RAD51 associated protein 1 (RAD51AP1), which plays a crucial role in HRR and primarily participates in forming D-loop, was reported as an essential protein for maintaining cellular genomic stability. However, recent studies showed that RAD51AP1 was significantly overexpressed in various cancer types and correlated with poor prognosis. These results suggested that RAD51AP1 may play a significant pro-cancer effect in multiple cancers. The underlying mechanism is still unclear. Cancer stemness-maintaining effects of RAD51AP1 might be considered as the most reliable mechanism. Meanwhile, RAD51AP1 also promoted resistance to radiation therapy and chemotherapy in many cancers. Thus, researches focused on RAD51AP1, and its regulatory molecules may provide new targets for overcoming cancer progression and treatment resistance. Here, we reviewed the latest research on RAD51AP1 in cancers and summarized its differential expression and prognostic implications. In this review, we also outlined the potential mechanisms of its pro-cancer and drug resistance-promoting effects to provide several potential directions for further research.
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Humans ; DNA-Binding Proteins/metabolism* ; RNA-Binding Proteins/metabolism* ; Lung Neoplasms ; DNA Repair ; Genomic Instability ; Rad51 Recombinase/metabolism*

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.
Animals ; Male ; Female ; Mice ; Humans ; CRISPR-Cas Systems/genetics* ; RNA, Guide, CRISPR-Cas Systems ; Rad51 Recombinase/genetics* ; Mice, Inbred C57BL ; Disease Models, Animal ; Recombination, Genetic

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.
Animals ; Cell Cycle Proteins/genetics* ; Cell Line ; Cell Survival ; Chondroitin Sulfate Proteoglycans/genetics* ; Chromosomal Proteins, Non-Histone/genetics* ; Gene Expression Regulation ; Gene Knockdown Techniques ; Infertility, Male ; Male ; Meiosis/genetics* ; Mice ; Mice, Knockout ; Mice, Transgenic ; Phosphate-Binding Proteins/genetics* ; Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics* ; Rad51 Recombinase/genetics* ; Real-Time Polymerase Chain Reaction ; Spermatocytes/metabolism* ; Spermatogenesis/genetics* ; Spermatogonia/metabolism*

PURPOSE: The characteristic expression of DNA damage response proteins in familial breast cancers with BRCA1, BRCA2, or non-BRCA1/2 mutations has not been analyzed in Chinese patients. Our study aimed to assess the differential expression of microcephalin 1 (BRIT1), ATM serine/threonine kinase (ATM), checkpoint kinase 2 (CHEK2), BRCA1, RAD51 recombinase (RAD51), and poly (ADP-ribose) polymerase 1 (PARP-1) and establish the profile of Chinese familial breast cancers with different mutation status. METHODS: We constructed five tissue microarrays from 183 familial breast cancer patients (31 with BRCA1 mutations; 14 with BRCA2 mutations, and 138 with non-BRCA1/2 mutations). The DNA response and repair markers used for immunohistochemistry analysis included BRIT1, ATM, CHEK2, BRCA1, RAD51, and PARP-1. The expressions of these proteins were analyzed in BRCA1/2 mutated tumors. The association between pathologic characteristics with BRCA1/2 mutation status was also analyzed. RESULTS: In familial breast cancer patients, BRCA1 mutated tumors were more frequent with high nuclear grade, estrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 negative, low Ki-67, and positive CK5/6. BRCA1 mutated tumors had lower CHEK2 and higher cytoplasmic BRIT1 expression than BRCA2 and non-BRCA1/2 mutation tumors. BRCA2-associated tumors showed higher CHEK2 and cytoplasmic RAD51 expression than those in other groups. Nuclear PARP-1 expression in BRCA1/2-associated tumors was significantly higher than in non-BRCA1/2 mutation tumors. Moreover, we found quite a few of negative PARP-1 expression cases in BRCA1/2 mutated groups. CONCLUSION: The clinicopathologic findings of BRCA1-associated Chinese familial breast cancers were similar to the results of other studies. Chinese familial breast cancer patients with BRCA1/2 mutations might have distinctive expression of different DNA damage response proteins. The reduced expression of PARP-1 in Chinese BRCA1/2 mutated breast cancer patients could influence the therapeutic outcome of PARP-1 inhibitors.
Asian Continental Ancestry Group* ; Breast Neoplasms* ; Breast* ; Checkpoint Kinase 2 ; Cytoplasm ; DNA Damage* ; DNA Repair ; DNA* ; Estrogens ; Genes, BRCA1 ; Genes, BRCA2 ; Humans ; Immunohistochemistry ; Phosphotransferases ; Rad51 Recombinase ; Receptor, Epidermal Growth Factor

BACKGROUNDOvarian serous adenocarcinoma can be divided into low- and high-grade tumors, which exhibit substantial differences in pathogenesis, clinicopathology, and prognosis. This study aimed to investigate the differences in the PH domain leucine-rich repeat protein phosphatase (PHLPP), forkhead homeobox type O 3a (FoxO3a), and RAD51 protein expressions, and their associations with prognosis in patients with low- and high-grade ovarian serous adenocarcinomas.

METHODSThe PHLPP, FoxO3a, and RAD51 protein expressions were examined in 94 high- and 26 low-grade ovarian serous adenocarcinomas by immunohistochemistry. The differences in expression and their relationships with pathological features and prognosis were analyzed.

RESULTSIn high-grade serous adenocarcinomas, the positive rates of PHLPP and FoxO3a were 24.5% and 26.6%, while in low-grade tumors, they were 23.1% and 26.9%, respectively (P < 0.05 vs. the control specimens; low- vs. high-grade: P > 0.05). The positive rates of RAD51 were 70.2% and 65.4% in high- and low-grade serous adenocarcinomas, respectively (P < 0.05 vs. the control specimens; low- vs. high-grade: P > 0.05). Meanwhile, in high-grade tumors, Stage III/IV tumors and lymph node and omental metastases were significantly associated with lower PHLPP and FoxO3a and higher RAD51 expression. The 5-year survival rates of patients with PHLPP- and FoxO3a-positive high-grade tumors (43.5% and 36.0%) were significantly higher than in patients with PHLPP-negative tumors (5.6% and 7.2%, respectively; P< 0.05). Similarly, the 5-year survival rate of RAD51-positive patients (3.0%) was significantly lower than in negative patients (42.9%; P< 0.05). In low-grade tumors, the PHLPP, FoxO3a, and RAD51 expressions were not significantly correlated with lymph node metastasis, omental metastasis, Federation of Gynecology and Obstetrics stage, or prognosis.

CONCLUSIONSAbnormal PHLPP, FoxO3a, and RAD51 protein expressions may be involved in the development of high- and low-grade ovarian serous adenocarcinomas, suggesting common molecular pathways. Decreased PHLPP and FoxO3a and increased RAD51 protein expression may be important molecular markers for poor prognosis, and RAD51 may be an independent prognosis factor, of high-grade, but not low-grade, ovarian serous adenocarcinomas.

Adult ; Aged ; Biomarkers, Tumor ; metabolism ; Cystadenocarcinoma, Serous ; metabolism ; pathology ; Female ; Forkhead Box Protein O3 ; metabolism ; Humans ; Immunohistochemistry ; Lymphatic Metastasis ; Middle Aged ; Neoplasm Staging ; Nuclear Proteins ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; Phosphoprotein Phosphatases ; metabolism ; Prognosis ; Rad51 Recombinase ; metabolism

OBJECTIVETo investigate the relationship between RAD51-G135C and XRCC3-C241T single nucleotide polymorphisms and onset of acute myeloid leukemia (AML).

METHODSThe study was performed in 2 groups: AML patient group and normal person group as control group. Genomic DNA was extracted from peripheral blood cells of 545 AML patients and 1 034 normal persons. Genotypes of RAD51-G135C and XRCC3-C241T were analyzed by TaqMan probe technology and the ralatienship between RAD51-G135C/XRCC3-C241T polymorphisms and onset of acute myeloid leukemia was investigated.

RESULTSCompared with the control group, RAD51-G135C homozygous mutant (CC) could significantly increase the risk of AML patients (OR=3.07), and there was no statistical relationship between heterozygous mutant (GC) of RAD51-G135C and onset of AML. There was no statistical relationship between homozygous mutant (TT) of XRCC3-C241T and onset of AML, and the XRCC3-C241T heterozygous mutation type (CT) increased the risk of AML patients (OR=0.66).

CONCLUSIONRAD51-G135C homozygous mutant and XRCC3-C241T heterozygous mutation significantly increase the risk of the AML onset, which can provide more predictive value for incidence of AML.

DNA-Binding Proteins ; Heterozygote ; Homozygote ; Humans ; Leukemia, Myeloid, Acute ; Polymorphism, Single Nucleotide ; Rad51 Recombinase

Ovarian carcinoma is the most lethal gynecologic malignancy. Resistance to platinum is considered the major problem affecting prognosis. Our recent study established that microRNA-506 (miR-506) expression was closely associated with progression-free survival and overall survival in two independent patient cohorts totaling 598 epithelial ovarian cancer cases. Further functional study demonstrated that miR-506 could augment the response to cisplatin and olaparib through targeting RAD51 and suppressing homologous recombination in a panel of ovarian cancer cell lines. Systemic delivery of miR-506 in an orthotopic ovarian cancer mouse model significantly augmented the cisplatin response, thus recapitulating the clinical observation. Therefore, miR-506 plays a functionally important role in homologous recombination and has important therapeutic value for sensitizing cancer cells to chemotherapy, especially in chemo-resistant patients with attenuated expression of miR-506.
Animals ; Antineoplastic Agents ; Cell Line, Tumor ; Cisplatin ; Disease-Free Survival ; Drug Resistance, Neoplasm ; Drug Therapy, Combination ; Female ; Homologous Recombination ; Humans ; Mice ; MicroRNAs ; Ovarian Neoplasms ; Piperazines ; Prognosis ; Rad51 Recombinase

OBJECTIVEThe functional characters of MCF7 and HCC1937 cell lines were compared through the activity of BRCA1 and p53 following DNA damage in order to provide more research evidence for the related studies in both breast cancer cell lines.

METHODSThe protein level of BRCA1 and p53 in two breast cancer cell lines and the protein level of BRCA1 in MCF7, HCC1937 and HCC1937 wtBRCA1 breast cancer cell lines treated with 10Gy after 1 h, 4 h or 8 h were detected by western blotting analysis. The distribution and foci formation of BRCA1 in the cells were observed through immunostaining assay and the percentage of BRCA1 or Rad51 foci formation after ionizing radiation was calculated. Cell cycle profiling was analyzed using flow cytometry.

RESULTSMost of BRCA1 and p53 localized in nucleus, and both proteins responded to DNA damage in MCF7 cells. In MCF7 cells,BRCA1 and Rad51 foci formation respectively increased to (59.40 ± 3.66)% from (11.80 ± 3.51)% (t = 16.26, P < 0.05) and (73.90 ± 8.66) % from (16.70 ± 3.76) % (t = 10.49, P < 0.05) after 10 Gy 8 h ; p53 and p21 protein level was further separately induced and enhanced to (82.54 ± 1.04) from (23.75 ± 0.51) (t = 87.90, P < 0.05) and (90.95 ± 1.13) from (50.19 ± 0.89) ( t = 49.11, P < 0.05) after 10 Gy 8 h; and the cells were accumulated in G1 phase. In contrast to MCF7, in HCC1937 cell line, both of BRCA1 and p53 were defective in nucleus since both proteins were mutated; in response to DNA damage, BRCA1 foci formation was not found, p53 and p21 was not induced; there was no cell accumulation in both of G1-S and G2-M phases. However, after complementation of wild-type BRCA1 in HCC1937 cells, DNA damage-induced Rad51 foci formation increased to (61.70 ± 4.03) % from (6.22 ± 2.27) % (t = 20.78, P < 0.05) and accumulation of cells in G2-M phase was also restored after 10 Gy 8h , which was similar to that of in MCF7 cells.

CONCLUSIONSWe have identified that BRCA1 and p53 have dramatically different functions in MCF7 and HCC1937 cell lines in response to DNA damage.

Cell Cycle ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; DNA Damage ; Humans ; MCF-7 Cells ; Rad51 Recombinase ; Radiation, Ionizing ; Tumor Suppressor Protein p53 ; Ubiquitin-Protein Ligases

OBJECTIVETo investigate the impact of polymorphisms of DNA homologous recombination (HR) repair genes RAD51-G135C and XRCC3-C241T on the prognosis of acute myeloid leukemia (AML) with inv(16)/t(16;16)(CBFbeta-MYH1).

METHODSOne hundred and three de novo inv(16)/t(16;16) (CBFbeta-MYH11) AML patients were followed-up and retrospectively analyzed. Polymorphisms of RAD51-G135C and XRCC3-C241T were detected by PCR-RFLP. The prognostic factors,including sex, age, white blood cell count, platelet count, hemoglobin level, karyotype, KIT mutation, RAD51-G135C and XRCC3-C241T polymorphisms at diagnosis, for complete remission (CR) achievement, overall survival (OS) and relapse-free survival (RFS) were analyzed by univariate and multivariate analyses.

RESULTSThe median follow-up of all patients was 28 (1 - 106) months. The overall CR rate was 92.2%. The estimated 5-year OS and RFS rates were 43.6% (95% CI 37.7% - 49.5%) and 26.4% (95% CI 21.1% - 31.7%), and the median OS and RFS were 53 (95% CI 133.4 - 72.7) and 27 (95% CI 22.9 - 31.1) months, respectively. In multivariate analysis, higher WBC (P = 0.004) and older than 30 years of age (P = 0.035) were independent poor factors for CR achievement, the XRCC3-241T variant (P = 0.007) and higher WBC (P = 0.009) were independent poor factors for 5-year RFS, and higher WBC (P = 0.002) and trisomy 8 (P = 0.035) were independent poor factors for 5-year survival. Polymorphism of RAD51-G135C had no significant impact on the prognosis.

CONCLUSIONThe XRCC3-241T variant is an independent poor prognostic factor for AML with inv(16)/t(16;16)/CBFbeta-MYH11.

Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; Chromosome Inversion ; Chromosomes, Human, Pair 16 ; DNA-Binding Proteins ; genetics ; Female ; Humans ; Karyotype ; Leukemia, Myeloid, Acute ; diagnosis ; genetics ; Male ; Middle Aged ; Oncogene Proteins, Fusion ; genetics ; Polymorphism, Single Nucleotide ; Prognosis ; Rad51 Recombinase ; genetics ; Young Adult

OBJECTIVETo investigate the relationship between DNA homologous recombination (HR) repair genes RAD51-G135C/XRCC3-C241T polymorphisms and development of acute myeloid leukemia (AML) with recurrent chromosome translocation.

METHODSGenomic DNA was extracted from bone marrow cells of 625 de novo AML patients and peripheral blood cells of 806 patient family members and 704 unrelated volunteers. Genotypes of RAD51-G135C and XRCC3-C241T were analyzed by PCR-RFLP. Cell lines with genotypes differed from XRCC3-C241T were selected and irradiated in vitro. The CBFβ-MYH11 fusion gene was detected by TaqMan real-time PCR.

RESULTSThe XRCC3-C241T variant (C/T + T/T) showed 6.22-fold and 6.99-fold increase in the risk of developing the AML with inv(16)/t(16;16)/CBFβ-MYH11 as compared with the volunteer and family member controls respectively; the RAD51-G135C homozygote-type (C/C) variant showed 0.87-fold (P = 0.010) and 1.15-fold (P = 0.001) respectively increase in the risk of this subtype AML. In the irradiated group, the CBFβ-MYH11 mRNA level in HL-60 cells was 59.49 times increased than that in KG1a cells. However, the RAD51-G135C and XRCC3-C241T variants had no correlations with the risk of development of t(15;17)/PML-RARα(+)AML, t(8;21)/AML1-ETO(+) AML and 11q23 AML subtypes.

CONCLUSIONThe XRCC3-C241T variant and the RAD51-G135C homozygote-type significantly increase the risk of the development of AML with inv(16)/t(16;16)/CBFβ-MYH11.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Case-Control Studies ; Child ; Child, Preschool ; DNA-Binding Proteins ; genetics ; Female ; Genetic Predisposition to Disease ; Genotype ; Humans ; Leukemia, Myeloid, Acute ; etiology ; genetics ; Male ; Middle Aged ; Oncogene Proteins, Fusion ; genetics ; Polymorphism, Single Nucleotide ; Rad51 Recombinase ; genetics ; Translocation, Genetic ; Young Adult