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Purpose:Proliferating cell nuclear antigen (PCNA) plays an essential role in regulating DNA synthesis and repair and is indispensable to cancer cell growth and survival. We previously reported a novel cancer associated PCNA isoform (dubbed caPCNA), which was ubiquitously expressed in a broad range of cancer cells and tumor tissues, but not significantly in nonmalignant cells. We found the L126-Y133 region of caPCNA is structurally altered and more accessible to protein–protein interaction. A cell-permeable peptide harboring the L126-Y133 sequence blocked PCNA interaction in cancer cells and selectively kills cancer cells and xenograft tumors. On the basis of these findings, we sought small molecules targeting this peptide region as potential broad-spectrum anticancer agents.Experimental Design:By computer modeling and medicinal chemistry targeting a surface pocket partly delineated by the L126-Y133 region of PCNA, we identified a potent PCNA inhibitor (AOH1160) and characterized its therapeutic properties and potential toxicity.Results:AOH1160 selectively kills many types of cancer cells at below micromolar concentrations without causing significant toxicity to a broad range of nonmalignant cells. Mechanistically, AOH1160 interferes with DNA replication, blocks homologous recombination–mediated DNA repair, and causes cell-cycle arrest. It induces apoptosis in cancer cells and sensitizes them to cisplatin treatment. AOH1160 is orally available to animals and suppresses tumor growth in a dosage form compatible to clinical applications. Importantly, it does not cause significant toxicity at 2.5 times of an effective dose.Conclusions:These results demonstrated the favorable therapeutic properties and the potential of AOH1160 as a broad-spectrum therapeutic agent for cancer treatment.

Supplementary Figures Supplemental figure legend: Figure S1. A diagram illustrating the process of virtual screen and follow-up cellular assays used in compound triage. The virtual screen by the computer modeling programs, MOE and Glide, is based on the known crystal structures of the PCNA/FEN1 complex that are available from the RCSB protein database. The cellular assays that led to the identification of AOH39 is described in Figure S3. Figure S2. The chemical structures of the 57 hits (AOH compounds) identified by the virtual screen. Compounds sharing structural similarities are organized on the same rows. Compounds that showed inhibitory activities on cancer cells are highlighted. Figure S3. Effect of AOH compounds on cell growth. The SK-N-AS and SK-N-DZ NB cells and human PBMCs were incubated in the presence of various concentrations of the indicated AOH compounds for 72 hours. The cell growth was measured by a CellTiter-Glo assay (Promega, Madison, WI). The relative cell abundance was graphed by Prism. Figure S4. Effect of AOH1160 on NCI60 cancer cells. AOH1160 was submitted to the Developmental Therapeutics Program (DTP) of the National Cancer Institute (NCI). The compound was tested in the NCI60 cell lines in the standard 5-dose assay as described (https://dtp.cancer.gov/discovery_development/nci-60/methodology.htm). Briefly, cells were incubated in the presence of various concentrations of AOH1160 for 48 hours. Cells growth was analyzed by a Sulforhodamine B (SRB) assay after cells were fixed by ice-cold 10% trichloroacetic acid (TCA). The GI50 in molar for each cell line was calculated by DTP. Shown in the graph are the LogGI50. Figure S5. Enhanced sensitivity to cisplatin by AOH1160. Human SK-N-AS NB cells were treated with or without 1 �M of cisplatin (CPT) in the presence or absence of 500 nM of AOH1160 for 18 h. Cells were washed with growth medium and were cultured in fresh media for 3 weeks to allow colony formation. The normalized colony counts under each treatment condition in triplicates were averaged and graphed plus/minus standard deviations. Based on Bliss independence model (see Methods), the combination index (Cl) for 1 �M of CPT and 500 nM of AOH1160 is about 0.74.

Supplementary report

Figure Legends Supplemental figure legend: Figure S1. A diagram illustrating the process of virtual screen and follow-up cellular assays used in compound triage. The virtual screen by the computer modeling programs, MOE and Glide, is based on the known crystal structures of the PCNA/FEN1 complex that are available from the RCSB protein database. The cellular assays that led to the identification of AOH39 is described in Figure S3. Figure S2. The chemical structures of the 57 hits (AOH compounds) identified by the virtual screen. Compounds sharing structural similarities are organized on the same rows. Compounds that showed inhibitory activities on cancer cells are highlighted. Figure S3. Effect of AOH compounds on cell growth. The SK-N-AS and SK-N-DZ NB cells and human PBMCs were incubated in the presence of various concentrations of the indicated AOH compounds for 72 hours. The cell growth was measured by a CellTiter-Glo assay (Promega, Madison, WI). The relative cell abundance was graphed by Prism. Figure S4. Effect of AOH1160 on NCI60 cancer cells. AOH1160 was submitted to the Developmental Therapeutics Program (DTP) of the National Cancer Institute (NCI). The compound was tested in the NCI60 cell lines in the standard 5-dose assay as described (https://dtp.cancer.gov/discovery_development/nci-60/methodology.htm). Briefly, cells were incubated in the presence of various concentrations of AOH1160 for 48 hours. Cells growth was analyzed by a Sulforhodamine B (SRB) assay after cells were fixed by ice-cold 10% trichloroacetic acid (TCA). The GI50 in molar for each cell line was calculated by DTP. Shown in the graph are the LogGI50. Figure S5. Enhanced sensitivity to cisplatin by AOH1160. Human SK-N-AS NB cells were treated with or without 1 �M of cisplatin (CPT) in the presence or absence of 500 nM of AOH1160 for 18 h. Cells were washed with growth medium and were cultured in fresh media for 3 weeks to allow colony formation. The normalized colony counts under each treatment condition in triplicates were averaged and graphed plus/minus standard deviations. Based on Bliss independence model (see Methods), the combination index (Cl) for 1 �M of CPT and 500 nM of AOH1160 is about 0.74.

US emergency departments are facing a number of operational challenges related to chronic shortages of registered nurses. Many of the tasks done by registered nurses can be safely and successfully delegated to the emergency department technician (EDT), particularly if a hospital's nursing and administrative leadership are affirmatively engaged in a process to professionalize and train their EDT workforce. This paper examines the state, Joint Commission on Accreditation of Healthcare Organizations, and Centers for Medicare & Medicaid Services regulatory landscape for the EDT, reviews the literature on how hospital's utilize EDT's, discusses approaches to skills training, and examines the need for profession standardization that enables job role expansion.