Hypersensitive Inhibition of the Proliferation of Cells with Mutated DNA Repair-Related Genes by the Catalytic Topoisomerase II Inhibitor 20-O-IngenolEZ

We previously reported that many ingenol compounds derived from Euphoria kansui exhibit topoisomerase inhibitory activity. 20-O-ingenolEZ in these compounds exerted inhibitory effects on both topoisomerase II (topo II) activity and cell proliferative activity. Topoisomerase II inhibitors can be divided into the poison and catalytic inhibitor types and 20-O-ingenolEZ is a catalytic inhibitor and inhibits topo IIα through inhibition of ATPase activity, but induces topo II-mediated DNA damage and apoptosis in BLM-/- DT40 cells through the induction of the DNA damage checkpoint, similar to the poison type inhibitor adriamycin. The ATPase inhibitor of topo II ICRF-193 also showed poison-like characteristics in the same cell line. However, the inhibitory effects of ICRF-193 on the proliferation of BLM-/- DT40 cells differed from those of 20-O-ingenolEZ, as did the specificity of its inhibition of the proliferation of other cell lines. 20-O-ingenolEZ showed hypersensitive inhibition of the proliferation of MCF-7 cells and BLM-/- DT40 cells with mutated DNA repair-related genes.

Mutation profiles of classic myeloproliferative neoplasms detected by a customized next-generation sequencing-based 50-gene panel

Objective:A sequencing panel consisting of 50 genes was customized to reveal the potential molecular land-scapes of essential thrombocytosis,polycythemia vera,and primary myelofibrosis in Chinese patients with myeloproliferative neoplasm(MPN).Methods:Sixty-five MPN patients(38 with essential thrombocytosis,21 with polycythemia vera,and 6 with primary myelofibrosis),including 12 triple-negative patients,were recruited and were screened for their mutational spectrum using next-generation sequencing technology in this retrospective observational study.This study was approved by the Institutional Review Board of Changhai Hospital,Naval Military Medical University,China.Results:In addition to the typical driver mutations in JAK2,CALR,and MPL,pathogenic mutations in 15 other genes were frequently detected among the 65 patients with MPN.The 15 mutated genes were TET2,EZH2,ASXL1,MIR662,MLH1,MLH3,SF3B1,MSH6,BARD1,DNMT3A,KIT,MSH2,RUNX1,TP53,and NRAS in this order according to the mutational frequency detected.The average number of mutated genes was 1.2 genes per patient,while in the 12 triple-negative patients with MPN(ie,patients that lack the JAK2,CALR,or MPL mutations),at least one of the 15 pathogenic mutations was detected for each patient.Interestingly,4 single nucleotide polymorphisms(rs4858647,rs9376092,rs58270997,rs621940)that might be correlated to individual susceptibility to myeloproliferative neoplasm were identified among the 65 patients.We also found that single nucleotide polymorphism and/or single nucleotide variation mutations occurred in multiple loci of mismatch repair-related genes,which might contribute to the development of MPN.Conclusion:Our study confirms the importance of the previously known MPN relative genes and,more importantly,provides some new and potentially valuable information about mutations associated with MPNs.