Growth factor regulation of secreted matrix metalloproteinase and plasminogen activators in prostate cancer cells, normal prostate fibroblasts and normal osteoblasts

Osteoblasts Promote Prostate Cancer Cell Proliferation Through Androgen Receptor Independent Mechanisms

Patients with metastatic prostate cancer frequently develop bone metastases that elicit significant skeletal morbidity and increased mortality. The high tropism of prostate cancer cells for bone and their tendency to induce the osteoblastic-like phenotype are a result of a complex interplay between tumor cells and osteoblasts. Although the role of osteoblasts in supporting prostate cancer cell proliferation has been reported by previous studies, their precise contribution in tumor growth remains to be fully elucidated. Here, we tried to dissect the molecular signaling underlining the interactions between castration-resistant prostate cancer (CRPC) cells and osteoblasts using in vitro co-culture models. Transcriptomic analysis showed that osteoblast-conditioned media (OCM) induced the overexpression of genes related to cell cycle in the CRPC cell line C4-2B but, surprisingly, reduced androgen receptor (AR) transcript levels. In-depth analysis of AR expression in C4-2B cells after OCM treatment showed an AR reduction at the mRNA (p = 0.0047), protein (p = 0.0247), and functional level (p = 0.0029) and, concomitantly, an increase of C4-2B cells in S-G2-M cell cycle phases (p = 0.0185). An extensive proteomic analysis revealed in OCM the presence of some molecules that reduced AR activation, and among these, Matrix metalloproteinase-1 (MMP-1) was the only one able to block AR function (0.1 ng/ml p = 0.006; 1 ng/ml p = 0.002; 10 ng/ml p = 0.0001) and, at the same time, enhance CRPC proliferation (1 ng/ml p = 0.009; 10 ng/ml p = 0.033). Although the increase of C4-2B cell growth induced by MMP-1 did not reach the proliferation levels observed after OCM treatment, the addition of Vorapaxar, an MMP-1 receptor inhibitor (Protease-activated receptor-1, PAR-1), significantly reduced C4-2B cell cycle (0.1 μM p = 0.014; 1 μM p = 0.0087). Overall, our results provide a novel AR-independent mechanism of CRPC proliferation and suggest that MMP-1/PAR-1 could be one of the potential pathways involved in this process.

Integrin β3 targeting biomaterial preferentially promotes secretion of bFGF and viability of iPSC-derived vascular smooth muscle cells

Human-induced pluripotent stem cell-derived-vascular smooth muscle cells (hiPSC-VSMC) and their secretome have been shown to promote angiogenesis and wound healing. However, there is a paucity of research on how the extracellular matrix (ECM) microenvironment may impact the hiPSC-VSMC's functions. In this study, we investigated the effect of specific ECM ligand-integrin interaction on hiPSC-VSMC's paracrine secretion, cell viability, and morphology. Here, we show precise modulation of hiPSC-VSMC in a fibronectin functionalized fibrillar collagen scaffold by targeting their integrin β3. The secretion of proangiogenic growth factor, basic fibroblast growth factor (bFGF) was found to be fibronectin-dependent via αvβ3 integrin interactions. In addition, our data show the possible role of a positive feedback loop between integrin β3, bFGF, and matrix metalloproteinase-2 in regulating hiPSC-VSMC's morphology and cell viability. Finally, the secretome with enhanced bFGF shows potential for future wound healing applications.

The Design, Characterizations, and Tumor Angiogenesis Inhibition of a Multi-Epitope Peptibody With bFGF/VEGFA

Tumor angiogenesis is dependent on growth factors, and inhibition of their pathways is one of the promising strategies in cancer therapy. However, resistance to single pathway has been a great concern in clinical trials so that it necessitates multiple targetable factors for developing tumor angiogenesis inhibitors. Moreover, the strategy of Fc fusion protein is an attractive platform for novel peptide agents, which gains increasing importance with FDA approval because of better immunogenicity and stability. Here, we applied the Fc fusion protein concept to bFGF/VEGFA pathways and designed a multi-epitope Peptibody with immunogenic peptides derived from human bFGF and VEGFA sequences. Immunization with Peptibody could elicit high-titer anti-bFGF and anti-VEGFA antibodies, activate T cells, and induce Th1/Th2-type cytokines. In in vitro experiments, the isolated anti-Peptibody antibody inhibited the proliferation and migration of A549 cells and human umbilical vein endothelial cells (HUVECs) by decreasing the MAPK/Akt/mTOR signal pathways. In the murine tumor model, pre-immunization with Peptibody suppressed the tumor growth and neovascularization of lung cancer by decreasing the production of bFGF/VEGFA/PDGF, the MAPK/Akt/mTOR signal pathways, and the activation of suppressive cells in tumor sites. Further, the biological characterizations of the recombinant Peptibody were investigated systematically, including protein primary structure, secondary structure, stability, and toxicity. Collectively, the results highlighted the strategy of bFGF/VEGFA pathways and Fc fusion protein in suppressing tumor progression and angiogenesis, which emphasized the potential of multiple targetable factors for producing enduring clinical responses in tumor patients.

Growth Differentiation Factor 5 (GDF-5) Induces Matrix Metalloproteinase 2 (MMP-2) Expression in Periodontal Ligament Cells and Modulates MMP-2 and MMP-13 Activity in Osteoblasts

Growth differentiation factor 5 (GDF-5), a member of the transforming growth factor beta (TGF-β) superfamily expressed in periodontal tissues, promotes extracellular matrix (ECM) in periodontal ligament (PDL) cells. Matrix metalloproteinases (MMP) are proteolytic enzymes that degrade ECM and are expressed in PDL cells. To date, little is known about the regulation of MMP synthesis and secretion in PDL cells. The aim of this study is to examine the effects of GDF-5 on MMP production and activity in PDL cells. GDF-5 increased both collagen type I alpha 2 (Col Iα2) and MMP-2 gene expression in cells derived from mouse PDL tissues after 3 days of culture. Because PDL cells represent a heterogeneous population, we examined gelatinolytic activity and gene expression profiles in an osteoblast cell line. After 6, 12, 24, and 48 hours of culture, GDF-5 increased both Col Iα2 and MMP gene expression in osteoblasts. GDF-5 also promoted MMP-2 activity as revealed by gelatin zymography after 7 days of culture. In the presence of the p38 MAP kinase inhibitor SB202190, on the other hand, MMP-2 activity was blocked. Taken together, these results indicate that GDF-5 may increase simultaneously the gene expression of type I collagen and MMP-2 in the osteoblast-like cells among the PDL cells and p38 MAP kinase pathway in osteoblast could involve in the regulation of MMP-2 enzyme activity induced by GDF-5.

Effect of bFGF on invasion of ovarian cancer cells through the regulation of Ets-1 and urokinase-type plasminogen activator

The aim of the study was to explore the role of basic fibroblast growth factor (bFGF) in ovarian cancer progression. This was done by investigating the effects of bFGF on both the secretion of urokinase-type plasminogen activator (uPA) and the invasion of tumor cells in SKOV(3) ovarian cancer cells. Human ovarian cancer cell line SKOV(3) was cultured in vitro. The expression of uPA gene and protein was induced in SKOV(3) cells; the impact of bFGF on the expression of uPA gene in SKOV(3) cells was studied by RT-PCR, and the impact of bFGF on the expression of uPA protein was tested by ELISA. Ets-1 antisense oligonucleotides were transfected into SKOV(3) cells by liposome protocol. The effects of bFGF on Ets-1 expression and the invasion ability of SKOV(3) cells were determined both before and after exposure to different concentrations of bFGF for 24 h. The expression of both uPA gene and protein was induced in SKOV(3) cells, p < 0.05. The expression of uPA was suppressed by Ets-1 antisense oligonucleotides in SKOV(3) cells, p < 0.05. The invasion ability of SKOV(3) cells was increased by 2.3-fold, and this effect was also suppressed by Ets-1 antisense oligonucleotides. bFGF can enhance the invasion ability of ovarian cancer cells in vitro by inducing the expression of uPA, and this effect is also regulated by the transcription factor Ets-1.

CXCR4 and matrix metalloproteinase-1 are elevated in breast carcinoma-associated fibroblasts and in normal mammary fibroblasts exposed to factors secreted by breast cancer cells

The complex molecular communications that occur between neoplastic and stromal cells within the tumor microenvironment play an integral role in breast cancer pathogenesis. Carcinoma-associated fibroblasts (CAF) produce tumor-enhancing factors and have been strongly implicated in breast cancer development. Similar to the way in which tumors have been compared with "wounds that never heal," CAFs have been equated to activated fibroblasts, which are present in inflammatory environments, in which they aid in wound healing through tissue remodeling and repair. Matrix metalloproteinase-1 (MMP-1) and G protein-coupled receptor, CXCR4, are elevated in these activated fibroblasts, in which they facilitate angiogenesis and matrix degradation, processes that are also vital to breast cancer metastasis. In this study, we investigated MMP-1 and CXCR4 expression in normal human mammary fibroblasts (HMF) exposed to soluble breast cancer factors. Historically, elevated CXCR4 expression is associated with breast cancer cells. However, we show that soluble factors secreted by SUM102 breast cancer cells stimulated the expression of MMP-1 and CXCR4 in HMFs. As a result, these stromal cells acquired an invasive and migratory phenotype. To confirm the clinical relevancy of our findings, we analyzed CAFs obtained from primary breast cancers. These cells also displayed elevated MMP-1 and CXCR4 levels compared with counterpart fibroblasts, and were more invasive and migratory. Together, our data suggest that soluble breast cancer factors initiate the transdifferentiation of normal HMFs to tumor-promoting CAFs, and that through the induction of MMP-1 and CXCR4 levels, these cells exhibit an invasive and migratory phenotype.

Effects of geldanamycin on HIF-1α mediated angiogenesis and invasion in prostate cancer cells

Geldanamycin (GA), a benzoquinone ansamycin, is a naturally occurring inhibitor of heat shock protein (Hsp90), which regulates the transcription activity of hypoxia-inducible factor 1 (HIF-1alpha). Under hypoxia, HIF-1alpha is activated in tumor cells, and induces the transcription of vascular endothelial growth factor (VEGF), which is the prime regulator for angiogenesis. VEGF promotes the formation of new blood vessels by stimulating endothelial cell division and migration. This eventually forms a vascular network that allows for tumor growth and metastasis. In this study, we used GA to inhibit HIF-1alpha transcription function. Human prostate cancer DU-145 cells were incubated in a hypoxic chamber at 1% O(2) and 37 degrees C for different durations. Both mRNA and protein levels of HIF-1alpha and VEGF were upregulated under hypoxic conditions. We demonstrated that GA treatment of hypoxic DU-145 cells abolished the induction of HIF-1alpha protein in a time-dependent manner and decreased VEGF mRNA and its protein levels. The transient transfection of DU-145 cells with luciferase reporter gene construct (5HRE/hCMVmp-luc) showed that the transcriptional activity of HIF-1alpha was significantly induced in response to hypoxia, but inhibited by GA. In addition, using conditioned medium from GA-treated hypoxic cells led to a significant decrease in cell invasion in comparison with using conditioned medium from nontreated hypoxic cells. These data provide evidence for the important role of GA in inhibition of angiogenesis and also invasion mediated by HIF-1alpha in prostate cancer cells.

Dual growth factor-induced angiogenesis in vivo using hyaluronan hydrogel implants

Crosslinked hyaluronan (HA) hydrogels preloaded with two cytokine growth factors, vascular endothelial growth factor (VEGF) and keratinocyte growth factor (KGF), were employed to elicit new microvessel growth in vivo. As a major glycosaminoglycan (GAG) component of extracellular matrix (ECM), HA is an excellent biopolymeric building block for new biomimetic, biocompatible therapeutic materials. HA hydrogel film samples were surgically implanted in the ear pinnae of mice, and the ears were harvested at 7 or 14 days post-implantation. Histologic analysis showed that each of the groups receiving an implant demonstrated significantly more microvessel density than control ears undergoing surgery but receiving no implant (p<0.001). Treatment groups receiving either co-delivery of both KGF and VEGF, an HA hydrogel lacking a growth factor or HA hydrogels containing a single cytokine were statistically unchanged with time, whereas treatment with KGF alone produced continuing increases in vascularization from day 7 to day 14. Strikingly, presentation of both VEGF and KGF in crosslinked HA generated intact microvessel beds with well-defined borders. In addition, an additive response to co-delivery of both cytokines in the HA hydrogel was observed. The HA hydrogels containing KGF+VEGF produced the greatest angiogenic response of any treatment group tested (NI=5.4 at day 14, where NI is a neovascularization index). This was 33% greater vessel density than in the next largest treatment group, that received HA+KGF (NI=4.0, p<0.002). New therapeutic approaches for numerous pathologies could be notably enhanced by the localized, sustained angiogenic response produced by release of both VEGF and KGF from crosslinked HA films.

Stimulation of in vivo angiogenesis by cytokine-loaded hyaluronic acid hydrogel implants

Crosslinked hyaluronic acid (HA) hydrogels were evaluated for their ability to elicit new microvessel growth in vivo when preloaded with one of two cytokines, vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF). HA film samples were surgically implanted in the ear pinnas of mice, and the ears retrieved 7 or 14 days post implantation. Histologic analysis showed that all groups receiving an implant demonstrated significantly more microvessel density than control ears undergoing surgery but receiving no implant (p < 0.01). Moreover, aqueous administration of either growth factor produced substantially more vessel growth than an HA implant with no cytokine. However, the most striking result obtained was a dramatic synergistic interaction between HA and VEGF. Presentation of VEGF in crosslinked HA generated vessel density of NI = 6.7 at day 14, where NI is a neovascularization index defined below, more than twice the effect of the sum of HA alone (NI = 1.8) plus VEGF alone (NI=1.3). This was twice the vessel density generated by co-addition of HA and bFGF (NI=3.4, p<0.001). New therapeutic approaches for numerous pathologies could be notably enhanced by the localized, synergistic angiogenic response produced by release of VEGF from crosslinked HA films.