Targeting the BMP Pathway in Prostate Cancer Induced Bone Disease

From the 33,000 men in the U.S. who die from prostate cancer each year, the majority of these patients exhibit metastatic disease with bone being the most common site of metastasis. Prostate cancer bone metastases are commonly blastic, exhibiting new growth of unhealthy sclerotic bone, which can cause painful skeletal related events. Patient’s current care entails androgen deprivation therapy, anti-resorptive agents, radiation, and chemotherapy to help control the spread of the cancer but little intervention is available to treat blastic bone disease. The transforming growth factor beta (TGFβ) and bone morphogenetic protein (BMP) pathways are known to regulate bone growth and resorption of destructive lytic bone lesions, yet the role of TGFβ/BMP signaling in prostate cancer blastic vs lytic bone lesions are not fully understood. We hypothesized that to target the BMP/TGFβ pathway, a useful biomarker of bone lytic or blastic pathology would have superior response. We show distinct BMP vs. TGFβ signaling in clinical samples of human prostate cancer bone metastases with either lytic or blastic pathologies. BMPs exhibit distinct effects on bone homeostasis, so to examine the effect of BMP inhibition on healthy bone, we treated mice with the BMP receptor small molecule antagonist DMH1 and saw a modest temporary improvement in bone health, with increased trabecular bone. We next sought to use the BMP inhibitor DMH1 to treat bone metastasis engraftment seeded by a caudal artery injection of the lytic human prostate cell line PC3 in immunodeficient mice. The colonization by PC3 cells to the bone were restricted with DMH1 treatment and bone health was importantly preserved. We next proceeded to test BMP inhibition in an injury model of established bone metastasis via intratibial injection of the MYC-CaP mouse prostate cell line into FVBN syngeneic mice. DMH1 treated mice had a modest decrease in trabecular bone and reduced lymphocytes in circulation without affecting tumor growth. Taken together we show unique responses to BMP inhibition in metastatic prostate cancer in the bone. These studies suggest that profiling bone lesions in metastatic prostate cancer can help identify therapeutic targets that not only treat the metastatic tumor but also address the need to better treat the distinct tumor induced bone disease.

Preliminary In Vitro Studies on Corynebacterium urealyticum Pathogenetic Mechanisms, a Possible Candidate for Chronic Idiopathic Prostatitis?

Corynebacterium urealyticum is a well-known opportunistic uropathogen that can occur with cystitis, pyelonephritis, and urinary sepsis. Although a wide variety of coryneform bacteria have been found from the male genital tract of prostatitis patients, only one clinical case of prostatitis caused by C. urealyticum has been reported. The aim of this study was to evaluate the in vitro tropism of C. urealyticum towards LNCaP (lymph node carcinoma of the prostate) human cells line and the influence of acetohydroxamic acid as an irreversible urease inhibitor on different aspects of its pathogenicity by means of several in vitro tests, such as the determination and analysis of growth curves, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, the production of biofilms, and adhesion to LNCaP and HeLa cell lines. Results have brought new pieces of evidence on the in vitro tropism of C. urealyticum for the human prostate cell line LNCaP and the therapeutic use of the irreversible urease inhibitors such as acetohydroxamic acid (AHA), not only as enzyme blockers to facilitate the removal of encrustations but also as modulators of some pathogenic mechanisms. These interesting preliminary data allow us to assert that there is a real possibility that C. urealyticum is a new candidate for chronic idiopathic prostatitis.

The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response

Adherent/invasiveEscherichia coli(AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenicE. coli(ExPEC), neonatal meningitis-associatedE. coli(NMEC), and uropathogenicE. coli(UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers.In silicoanalysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Ourin vitrodata support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract.

Cerebellar Degeneration-Related Autoantigen 1 (CDR1) Gene Expression in Prostate Cancer Cell Lines

Prostate cancer (PCa) is the most frequent cancer among men in many developing countries, and the second leading cause of cancer-related death in men. A genetic component has been implicated in PCa onset and development. The cerebellar degeneration-related autoantigen 1 ( CDR1) gene, mapping in Xq26-q27.2, is expressed in cerebrum, cerebellum, heart, lung, liver, and kidney. In addition, CDR1 expression has been detected in neuroblastoma, renal carcinoma cell lines, and other cancer cell lines. In this study, we investigated the expression of the CDR1 gene in the LNCaP and PC-3 PCa cell lines, and in the PNT1A normal prostate cell line. CDR1 mRNA expression was evaluated by qRT-PCR. We found that the CDR1 gene was overexpressed in the LNCaP and PC-3 PCa cell lines as compared with the PNT1A normal prostate cell line. These data suggest that CDR1 could be a new biomarker for PCa identification.

Studies on the Cytotoxic Activities of Punica granatum L. var. spinosa (Apple Punice) Extract on Prostate Cell Line by Induction of Apoptosis

The Punica granatum L. var. granatum (pomegranate) has been demonstrated to exert antitumor effects on various types of cancer cells. The present study aimed to evaluate the medicinal herbs Punica granatum L. var. spinosa (apple punice) that are native to Iran. This study was determined to test the possible cytotoxic activity and induction of apoptosis on human prostate cell lines. The effect of ethanol extracts of the herbs on the inhibition of cell proliferation was assessed by MTT colorimetric assay. PC3 cell lines treated with the extracts were analyzed for the induction of apoptosis by cell death detection (ELISA) and TUNEL assay. Dye exclusion analysis was performed for viability rate. Our results demonstrated that the Punica granatum L. var. spinosa extract dose dependently suppressed the proliferation of PC3 cells (IC50= 250.21 μg/mL) when compared with a chemotherapeutic anticancer drug (Toxol) (Vesper Pharmaceuticals) with increased nucleosome production from apoptotic cells. The Punica granatum L. var. spinosa extract attenuated the human prostate cell proliferation in vitro possibly by inducing apoptosis. The Punica granatum L. var. spinosa is likely to be valuable for the treatment of some forms of human prostate cell line.