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Identification of Fibulin‐1 as a Human Bone Marrow Stromal (HS‐5) Cell‐Derived Factor That Induces Human Prostate Cancer Cell Death
Author(s) -
Lertsuwan Kornkamon,
Choe Leila H.,
Marwa Irene R.,
Lee Kelvin,
Sikes Robert A.
Publication year - 2017
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.23303
Subject(s) - fibulin , stromal cell , prostate cancer , bone marrow , programmed cell death , cancer research , biology , microbiology and biotechnology , apoptosis , cancer , immunology , biochemistry , genetics , extracellular matrix
BACKGROUND Previous studies showed that human bone marrow stromal HS‐5 cells secreted unidentified factor(s) inducing PCa cell death. Herein, the HS‐5‐derived factor (HS‐5 DF) was characterized and identified. METHODS Conditioned media from confluent HS‐5 cells were collected and modified for biochemical characteristic testing of HS‐5 DF. Cell survival was measured by apoptosis assay and live/dead assay. Fibulin‐1 was identified from gel electrophoresis and mass spectrometry. The validation of Fibulin‐1 as a HS‐5 DF was done by immunoprecipitation (IP) and genetic knockdown by CRISPR/Cas9 system. RESULTS HS‐5 DF was trypsin and heat sensitive, but pH stable. The tentative size of the factor fell between 30 kDa and 100 kDa. TGF‐β1 treatment led to a suppression of HS‐5 DF activity, a property consistent with bone metastasis in prostate cancer. Examination of TGF‐β1 down regulated proteins led to identification of fibulin‐1 as a candidate for the DF. IP of Fibulin‐1 from HS‐5 CM and CRISPR knockdown of Fibulin‐1 showed a significant reduction of HS‐5 CM‐derived PCa cell death. These results strongly support a role for fibulin‐1 in HS‐5 bone marrow stromal cell induction of PCa cell death. CONCLUSION Our data indicate that Fibulin‐1 functions as a HS‐5 bone marrow stromal cell‐derived factor inducing prostate cancer cell death. Prostate 77:729–742, 2017 . © 2016 Wiley Periodicals, Inc.