title: Engineering a waste management enzyme to overcome cancer resistance to apoptosis: adding DNase1 to the anti-cancer toolbox.
abstract: Cancer treatment is often complicated by resistance to conventional anti-cancer treatment and to more recently developed immunotherapy and gene therapy. These therapeutic modalities aim at activating death pathways within cancer cells. Attempts to activate the apoptotic death pathway, by overexpressing proapoptotic signals, are compromised by cancer defense mechanisms, which disrupt the apoptotic-signaling cascade downstream of the overexpressed component. Here, we describe a therapeutic option of triggering apoptosis without activating the apoptotic-signaling cascade or using the native apoptosis executioner nuclease. We have engineered Deoxyribonuclease-1 (DNase1), a waste-management enzyme, by deleting its signal peptide, adding a nuclear localization signal, and mutating its actin-binding site. Apoptosis studies and colony-forming assay for assessing cell viability were conducted in apoptosis-resistant Mel-Juso human melanoma cells. The modified DNase1 reduced cell viability by 77% relative to controls. It also induced typical microscopic features of cellular apoptosis, such as Terminal Transferase dUTP Nick-End Labeling-positive cells and DNA fragmentation. Quantification of apoptosis by Laser scanning cytometry demonstrated high-killing efficiency of 70-100%. The results suggest that this modified DNase1 can efficiently eliminate apoptosis-resistant cancer cells through apoptosis. Coupled to different tissue-specific gene expression elements, this recombinant DNase1 may serve as a platform for eliminating a variety of cancer types.
authors.affiliation: Laboratory for Molecular Dermatology, Program in Molecular Biology and Genetics, Barbara Ann Karmanos Cancer Institute, Detroit, MI 48201, USA. krosner@med.wayne.edu
authors.forename: K
authors.initials: K
authors.lastname: Rosner
authors.forename: M F
authors.initials: MF
authors.lastname: Kasprzak
authors.forename: A C J
authors.initials: AC
authors.lastname: Horenstein
authors.forename: H L
authors.initials: HL
authors.lastname: Thurston
authors.forename: J
authors.initials: J
authors.lastname: Abrams
authors.forename: L Y
authors.initials: LY
authors.lastname: Kerwin
authors.forename: D A
authors.initials: DA
authors.lastname: Mehregan
authors.forename: D R
authors.initials: DR
authors.lastname: Mehregan
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D003114:Colony-Forming Units Assay; D053938:DNA Fragmentation; D003850:Deoxyribonuclease I / Q000378:metabolism*; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D020287:In Situ Nick-End Labeling; D047569:Laser Scanning Cytometry; D008545:Melanoma / Q000235:genetics / Q000628:therapy*; D015202:Protein Engineering / Q000379:methods*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*
chemical_list: C085693:DNASE1 protein, human; D003850:Deoxyribonuclease I