A Bifunctional PARP-HDAC Inhibitor with Activity in Ewing Sarcoma.

PURPOSE: Histone deacetylase (HDAC) inhibition has been shown to induce pharmacologic "BRCAness" in cancer cells with proficient DNA repair activity. This provides a rationale for exploring combination treatments with HDAC and PARP inhibition in cancer types that are insensitive to single-agent PARP inhibitors (PARPi). Here, we report the concept and characterization of a novel bifunctional PARPi (kt-3283) with dual activity toward PARP1/2 and HDAC enzymes in Ewing sarcoma cells. EXPERIMENTAL DESIGN: Inhibition of PARP1/2 and HDAC was measured using PARP1/2, HDAC activity, and PAR formation assays. Cytotoxicity was assessed by IncuCyte live cell imaging, CellTiter-Glo, and spheroid assays. Cell-cycle profiles were determined using propidium iodide staining and flow cytometry. DNA damage was examined by γH2AX expression and comet assay. Inhibition of metastatic potential by kt-3283 was evaluated via ex vivo pulmonary metastasis assay (PuMA). RESULTS: Compared with FDA-approved PARP (olaparib) and HDAC (vorinostat) inhibitors, kt-3283 displayed enhanced cytotoxicity in Ewing sarcoma models. The kt-3283-induced cytotoxicity was associated with strong S and G2-M cell-cycle arrest in nanomolar concentration range and elevated DNA damage as assessed by γH2AX tracking and comet assays. In three-dimensional spheroid models of Ewing sarcoma, kt-3283 showed efficacy in lower concentrations than olaparib and vorinostat, and kt-3283 inhibited colonization of Ewing sarcoma cells in the ex vivo PuMA model. CONCLUSIONS: Our data demonstrate the preclinical justification for studying the benefit of dual PARP and HDAC inhibition in the treatment of Ewing sarcoma in a clinical trial and provides proof-of-concept for a bifunctional single-molecule therapeutic strategy.

Patients may respond differently to paper and electronic versions of the same questionnaires.

AIM: To adapt the Asthma Quality of Life Questionnaire (AQLQ(S)), the Asthma Control Questionnaire (ACQ) and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ(S)) for a personal digital assistant (Palm TX) and to examine the validity of the electronic versions by comparing them with the original paper versions. METHODS: 84 adults with asthma and 32 with rhinitis were randomised to complete either the paper or the electronic version first. After 2h, they completed the other version. RESULTS: 68 asthma and 27 rhinitis patients provided analysable data. For the AQLQ(S) and RQLQ(S) differences between paper and electronic were significant. Concordance between paper and electronic, evaluated using an intraclass correlation coefficient were: AQLQ=0.92, ACQ=0.90 and RQLQ=0.85. Concordance for the individual domains of the AQLQ and RQLQ ranged from 0.52 to 0.94. These levels of concordance did not reach the a priori defined requirement for validity. CONCLUSIONS: The significant bias between paper and electronic versions and only modest concordance provides evidence that patients may respond differently to questionnaires in different formats and show that different formats must not be used interchangeably.