Purinergic Receptor Expression and Cellular Responses to Purinergic Agonists in Human Prostate Cancer Cells.

BACKGROUND: Anticancer activity of extracellular nucleotides has been investigated in many types of cancer. Herein, the effects of extracellular nucleotides and the receptor profile for these nucleotides on prostate cancer (PCa) were elaborated. MATERIALS AND METHODS: PCa cell lines representing different stages of PCa were used. The effects of ATP and adenosine on PCa growth and migration on different extracellular matrix proteins were examined by MTT and wound-healing assays. Purinergic receptor profiling was carried out by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: A growth-inhibitory effect of ATP and adenosine was observed on all PCa cell lines tested. Several ATP-recognized P2 receptors and adenosine receptors were commonly expressed in PCa cell lines. Neither ATP nor adenosine had any significant effect on PCa migration. CONCLUSION: ATP and adenosine had an antiproliferative effect on PCa cells without affecting their motility, indicating their potential as a novel therapy for PCa.

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-ß1 treatment led to a suppression of HS-5 DF activity, a property consistent with bone metastasis in prostate cancer. Examination of TGF-ß1 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.