title: The inhibition of human tumor cell proliferation by RNase Pol, a member of the RNase T1 family, from Pleurotus ostreatus.
abstract: RNase Po1 is a guanylic acid-specific ribonuclease (a RNase T1 family RNase) from Pleurotus ostreatus. We determined the cDNA sequence encoding RNase Po1 and expressed RNase Po1 in Escherichia coli. A comparison of the enzymatic properties of RNase Po1 and RNase T1 indicated that the optimum temperature for RNase Po1 activity was 20 °C higher than that for RNase T1. An MTT assay indicated that RNase Po1 inhibits the proliferation of human neuroblastoma cells (IMR-32 and SK-N-SH) and human leukemia cells (Jurkat and HL-60). Furthermore, Hoechst 33342 staining showed morphological changes in HL-60 cells due to RNase Po1, and flow cytometry indicated the appearance of a sub-G1 cell population. The extent of these changes was dependent on the concentration of RNase Pol. We suggest that RNase Po1 induces apoptosis in tumor cells.
authors.affiliation: School of Pharmacy, Nihon University, Funabashi, Chiba 274-8555, Japan. kobayashi.hiroko@nihon-u.ac.jp
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Naomi
authors.initials: N
authors.lastname: Motoyoshi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Itagaki
authors.forename: Keiichi
authors.initials: K
authors.lastname: Tabata
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Norio
authors.initials: N
authors.lastname: Inokuchi
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003001:Cloning, Molecular; D018922:HL-60 Cells; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D020076:Pleurotus / Q000201:enzymology* / Q000235:genetics; D006163:Ribonuclease T1 / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D006163:Ribonuclease T1