title: RNase activity of sialic acid-binding lectin from bullfrog eggs drives antitumor effect via the activation of p38 MAPK to caspase-3/7 signaling pathway in human breast cancer cells.
abstract: Sialic acid-binding lectin obtained from bullfrog eggs (SBL) induces cell death in cancer cells but not in normal cells. This antitumor effect is mediated through its ribonuclease (RNase) activity. However, the underlying molecular mechanisms remain unclear. We found that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated when SBL induced cell death in three human breast cancer cell lines: SK-BR-3, MCF-7, and MDA‑MB231. The suppression of p38 MAPK phosphorylation by a p38 MAPK inhibitor as well as short interference RNA knockdown of p38 MAPK expression significantly decreased cell death and increased the cell viability of SBL-treated MDA‑MB231 cells. H103A, an SBL mutant lacking in RNase activity, showed decreased SBL-induced cell death compared with native SBL. However, the loss of RNase activity of SBL had no effect on its internalization into cells. The H103A mutant also displayed decreased phosphorylation of p38 MAPK. Moreover, SBL promoted caspase‑3/7 activation followed by a cleavage of poly (ADP-ribose)-polymerase, whereas the SBL mutant, H103A, lost this ability. The SBL-induced caspase‑3/7 activation was suppressed by the p38 MAPK inhibitor, SB203580, as well as pan-caspase inhibitor, zVAD-fmk. In the presence of zVAD-fmk, the SBL-induced cell death was decreased. In addition, the cell viability of SBL-treated MDA‑MB231 cells recovered by zVAD-fmk treatment. Taken together, our results suggest that the RNase activity of SBL leads to breast cancer cell death through the activation of p38 MAPK followed by the activation of caspase‑3/7.
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan.
authors: Yukiko
authors: Y
authors: Kariya
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan.
authors: Takeo
authors: T
authors: Tatsuta
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan.
authors: Shigeki
authors: S
authors: Sugawara
authors: Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima City, Fukushima 960-1295, Japan.
authors: Yoshinobu
authors: Y
authors: Kariya
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan.
authors: Kazuo
authors: K
authors: Nitta
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan.
authors: Masahiro
authors: M
authors: Hosono
mesh_terms: D029845:Amphibian Proteins / Q000235:genetics / Q000494:pharmacology*; D000818:Animals; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D037102:Lectins / Q000235:genetics / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D061986:MCF-7 Cells; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects; D011892:Rana catesbeiana / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000235:genetics / Q000494:pharmacology*; D015843:Serpins / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D029845:Amphibian Proteins; D037102:Lectins; C102316:SERPINB9 protein, human; D015843:Serpins; D048051:p38 Mitogen-Activated Protein Kinases; D012260:Ribonucleases; C448662:leczyme protein, Rana; C505520:CASP7 protein, human; D053179:Caspase 7