Studies on DNA repair in early spermatid stages of male mice after in vivo treatment with methyl-, ethyl-, propyl-, and isopropyl methanesulfonate

IK is a mitotic factor that promotes cell cycle progression. Our previous investigation of 271 endometrial cancer (EC) samples from the Cancer Genome Atlas (TCGA) dataset showed IK somatic mutations were enriched in a cluster of patients with high-grade and high-stage cancers, and this group had longer survival. This study provides insight into how IK somatic mutations contribute to EC pathophysiology. We analyzed the somatic mutational landscape of IK gene in 547 EC patients using expanded TCGA dataset. Co-immunoprecipitation and mass spectrometry were used to identify protein interactions. In vitro and in vivo experiments were used to evaluate IK’s role in EC. The patients with IK-inactivating mutations had longer survival during 10-year follow-up. Frameshift and stop-gain were common mutations and were associated with decreased IK expression. IK knockdown led to enrichment of G2/M phase cells, inactivation of DNA repair signaling mediated by heterodimerization of Ku80 and Ku70, and sensitization of EC cells to cisplatin treatment. IK/Ku80 mutations were accompanied by higher mutation rates and associated with significantly better overall survival. Inactivating mutations of IK gene and loss of IK protein expression were associated with weakened Ku80/Ku70-mediated DNA repair, increased mutation burden, and better response to chemotherapy in patients with EC.

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Poly(ADP-ribose) molecules formed during DNA repair in vivo

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)32496-1 ◽

1994 ◽

Vol 269 (26) ◽

pp. 17691-17696 ◽

Cited By ~ 1

Author(s):

M. Malanga ◽

F.R. Althaus

Keyword(s):

Dna Repair

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The Large Subunit of Replication Factor C (Rfclp/Cdc44p) Is Required for DNA Replication and DNA Repair in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.1.65 ◽

1996 ◽

Vol 142 (1) ◽

pp. 65-78 ◽

Cited By ~ 7

Author(s):

Michael A McAlear ◽

K Michelle Tuffo ◽

Connie Holm

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Repair ◽

Dna Replication ◽

Uv Radiation ◽

Large Subunit ◽

Restrictive Temperature ◽

Replication Factor C ◽

Replication Factor ◽

Factor C

We used genetic and biochemical techniques to characterize the phenotypes associated with mutations affecting the large subunit of replication factor C (Cdc44p or Rfc1p) in Saccharomyces cerevisiae. We demonstrate that Cdc44p is required for both DNA replication and DNA repair in vivo. Cold-sensitive cdc44 mutants experience a delay in traversing S phase at the restrictive temperature following alpha factor arrest; although mutant cells eventually accumulate with a G2/M DNA content, they undergo a cell cycle arrest and initiate neither mitosis nor a new round of DNA synthesis. cdc44 mutants also exhibit an elevated level of spontaneous mutation, and they are sensitive both to the DNA damaging agent methylmethane sulfonate and to exposure to UV radiation. After exposure to UV radiation, cdc44 mutants at the restrictive temperature contain higher levels of single-stranded DNA breaks than do wild-type cells. This observation is consistent with the hypothesis that Cdc44p is involved in repairing gaps in the DNA after the excision of damaged bases. Thus, Cdc44p plays an important role in both DNA replication and DNA repair in vivo.

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MODL-16. ABEMACICLIB, A SELECTIVE CDK4/6 INHIBITOR, RESTRICTS GROWTH OF PEDIATRIC GLIAL-LINEAGE TUMORS IN VITRO AND IN VIVO

Neuro-Oncology ◽

10.1093/neuonc/noaa222.590 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii414-iii414

Author(s):

Muh-Lii Liang ◽

Tsung-Han Hsieh ◽

Tai-Tong Wong

Keyword(s):

Dna Repair ◽

Therapeutic Strategy ◽

Target Genes ◽

Rna Seq ◽

Downstream Target ◽

Rb Phosphorylation ◽

Glial Lineage

Abstract BACKGROUND Glial-lineage tumors constitute a heterogeneous group of neoplasms, comprising gliomas, oligodendrogliomas, and ependymomas, which account for 40%–50% of all pediatric central nervous system tumors. Advances in modern neuro-oncological therapeutics are aimed at improving neoadjuvant chemotherapy and deferring radiotherapy because radiation exposure may cause long-term side effects on the developing brain in young children. Despite aggressive treatment, more than half the high-grade gliomas (pHGGs) and one-third of ependymomas exhibit recurrence within 2 years of initial treatment. METHODS By using integrated bioinformatics and through experimental validation, we found that at least one gene among CCND1, CDK4, and CDK6 was overexpressed in pHGGs and ependymomas. RESULTS The use of abemaciclib, a highly selective CDK4/6 inhibitor, effectively inhibited cell proliferation and reduced the expression of cell cycle–related and DNA repair–related gene expression, which was determined through RNA-seq analysis. The efficiency of abemaciclib was validated in vitro in pHGGs and ependymoma cells and in vivo by using subcutaneously implanted ependymoma cells from patient-derived xenograft (PDX) in mouse models. Abemaciclib demonstrated the suppression of RB phosphorylation, downstream target genes of E2F, G2M checkpoint, and DNA repair, resulting in tumor suppression. CONCLUSION Abemaciclib showed encouraging results in preclinical pediatric glial-lineage tumors models and represented a potential therapeutic strategy for treating challenging tumors in children.

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