Satoshi Tanaka1, Kanayo Suzuki1, Minoru Sakaguchi2. 1. Laboratory of Cell Biology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan. 2. Laboratory of Cell Biology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan. sakaguti@gly.oups.ac.jp.
Abstract
BACKGROUND: Prolyl oligopeptidase (POP, EC 3.4.1.26) is a serine peptidase that hydrolyzes post-proline peptide bonds in peptides that are <30 amino acids in length. We previously reported that POP inhibition suppressed the growth of NB-1 human neuroblastomas cells and KATO III human gastric cancer cells. POP activity is commonly elevated in many cancers, which includes breast cancer. However, the effect of POP inhibition as a candidate breast cancer therapy is unknown. METHODS: The effects of POP inhibition and knockdown on the proliferation of cultured human estrogen receptor-positive (ER+) MCF7 and T47D, and ER-negative (ER-) MDA-MB-231 breast cancer cell lines and the MCF12A non-tumorigenic epithelial cell line were tested by analyzing their influence on cell proliferation (WST-1 assay), cell viability (trypan blue exclusion assay), and cell cycle arrest (cell cycle analysis, cell cycle regulator proteins expression). RESULTS: POP-specific inhibitors 3-({4-[2-(E)-styrylphenoxy]butanoyl}-L-4-hydroxyprolyl)-thiazolidine (SUAM-14746) and benzyloxycarbonyl-thiopropyl-thioprolinal and RNAi-mediated POP knockdown inhibited the proliferation of MCF7 cells without inducing cell death. SUAM-14746-induced growth inhibition was also observed in T47D and MDA-MB-231 cells, but not in MCF12A cells. This growth inhibition was associated with G1 phase arrest; reduced cyclin D1 and D3, cyclin-dependent kinase 4 (CDK4), E2F1, and retinoblastoma protein (pRb) expression; and increased cyclin-dependent kinase inhibitor 1B (p27kip1) expression. Moreover, the SUAM-14746-mediated cell cycle arrest of MCF7 cells was associated with increased pRb2/p130 protein expression and an increase in the number of cells in the quiescent G0 state, as defined by low RNA levels. CONCLUSIONS: SUAM-14746 inhibited breast cancer cell growth in a cytostatic manner without inducing lethality, and POP-specific inhibitors may be an effective treatment against ER+ and ER- breast cancer.
BACKGROUND:Prolyl oligopeptidase (POP, EC 3.4.1.26) is a serine peptidase that hydrolyzes post-proline peptide bonds in peptides that are <30 amino acids in length. We previously reported that POP inhibition suppressed the growth of NB-1 humanneuroblastomas cells and KATO III humangastric cancer cells. POP activity is commonly elevated in many cancers, which includes breast cancer. However, the effect of POP inhibition as a candidate breast cancer therapy is unknown. METHODS: The effects of POP inhibition and knockdown on the proliferation of cultured human estrogen receptor-positive (ER+) MCF7 and T47D, and ER-negative (ER-) MDA-MB-231 breast cancer cell lines and the MCF12A non-tumorigenic epithelial cell line were tested by analyzing their influence on cell proliferation (WST-1 assay), cell viability (trypan blue exclusion assay), and cell cycle arrest (cell cycle analysis, cell cycle regulator proteins expression). RESULTS:POP-specific inhibitors 3-({4-[2-(E)-styrylphenoxy]butanoyl}-L-4-hydroxyprolyl)-thiazolidine (SUAM-14746) and benzyloxycarbonyl-thiopropyl-thioprolinal and RNAi-mediated POP knockdown inhibited the proliferation of MCF7 cells without inducing cell death. SUAM-14746-induced growth inhibition was also observed in T47D and MDA-MB-231 cells, but not in MCF12A cells. This growth inhibition was associated with G1 phase arrest; reduced cyclin D1 and D3, cyclin-dependent kinase 4 (CDK4), E2F1, and retinoblastoma protein (pRb) expression; and increased cyclin-dependent kinase inhibitor 1B (p27kip1) expression. Moreover, the SUAM-14746-mediated cell cycle arrest of MCF7 cells was associated with increased pRb2/p130 protein expression and an increase in the number of cells in the quiescent G0 state, as defined by low RNA levels. CONCLUSIONS:SUAM-14746 inhibited breast cancer cell growth in a cytostatic manner without inducing lethality, and POP-specific inhibitors may be an effective treatment against ER+ and ER- breast cancer.
Entities:
Keywords:
Cell cycle arrest; Human breast cancer cell lines; Prolyl oligopeptidase; Quiescent G0 state; SUAM-14746
Authors: Ricardo E Perez; Sarah Calhoun; Daeun Shim; Victor V Levenson; Lei Duan; Carl G Maki Journal: Cancer Biol Ther Date: 2020-10-12 Impact factor: 4.742
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