Identification of Fibulin-1 as a Human Bone Marrow Stromal (HS-5) Cell-Derived Factor That Induces Human Prostate Cancer Cell Death.
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.


CONCLUSIONS
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.
Department of Biological Sciences, Center for Translational Cancer Research, University of Delaware, Newark, Delaware.|Department of Biological Sciences, Laboratory for Cancer Ontogeny and Therapeutics, University of Delaware, Newark, Delaware.
Kornkamon
K
Lertsuwan
Delaware Biotechnology Institute, Newark, Delaware.
Leila H
LH
Choe
Department of Biological Sciences, Center for Translational Cancer Research, University of Delaware, Newark, Delaware.|Department of Biological Sciences, Laboratory for Cancer Ontogeny and Therapeutics, University of Delaware, Newark, Delaware.
Irene R
IR
Marwa
Delaware Biotechnology Institute, Newark, Delaware.
Kelvin
K
Lee
Department of Biological Sciences, Center for Translational Cancer Research, University of Delaware, Newark, Delaware.|Department of Biological Sciences, Laboratory for Cancer Ontogeny and Therapeutics, University of Delaware, Newark, Delaware.
Robert A
RA
Sikes
D017209:Apoptosis / Q000502:physiology; D001859:Bone Neoplasms / Q000378:metabolism / Q000556:secondary; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D017077:Culture Media, Conditioned / Q000032:analysis / Q000378:metabolism; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
D002135:Calcium-Binding Proteins; D017077:Culture Media, Conditioned; D053773:Transforming Growth Factor beta1; C060820:fibulin
HS-5; bone marrow stromal cells; bone metastasis; fibulin-1; prostate cancer