Bone morphogenetic protein-2 (BMP-2) is a potent osteoinductive factor, yet its clinical use is limited by a short biological half-life, rapid local clearance and propensity for side effects. Heparin (HP), a highly sulfated glycosaminoglycan (GAG) that avidly binds BMP-2, has inherent biological properties that may circumvent these limitations. Here, we compared hyaluronan-based hydrogels formulated to include heparin (Heprasil™) with similar gels without heparin (Glycosil™) for their ability to deliver bioactive BMP-2 in vitro and in vivo. The osteogenic activity of BMP-2 released from the hydrogels was evaluated by monitoring alkaline phosphatase (ALP) activity and SMAD 1/5/8 phosphorylation in mesenchymal precursor cells. The osteoinductive ability of these hydrogels was determined in a rat ectopic bone model by 2D radiography, 3D µ-CT and histological analyses at 8 weeks post-implantation. Both hydrogels sustain the release of BMP-2. Importantly, the inclusion of a small amount of heparin (0.3% w/w) attenuated release of BMP-2 and sustained its osteogenic activity for up to 28 days. In contrast, hydrogels lacking heparin released more BMP-2 initially but were unable to maintain BMP-2 activity at later time points. Ectopic bone-forming assays using transplanted hydrogels emphasized the therapeutic importance of the initial burst of BMP-2 rather than its long-term osteogenic activity. Thus, tuning the burst release phase of BMP-2 from hydrogels may be advantageous for optimal bone formation.

Lowering the efficacious dose of bone morphogenetic protein-2 (BMP-2) for the repair of critical-sized bone defects is highly desirable, as supra-physiological amounts of BMP-2 have an increased risk of side effects and a greater economic burden for the healthcare system. To address this need, we explored the use of heparan sulfate (HS), a structural analog of heparin, to enhance BMP-2 activity. We demonstrate that HS isolated from a bone marrow stromal cell line (HS5) and heparin each enhances BMP-2-induced osteogenesis in C2C12 myoblasts, through increased ALP activity and osteocalcin mRNA expression. Commercially available HS variants from porcine kidney and bovine lung failed to generate similar effects. Heparin and HS5 influence BMP-2 activity by (i) prolonging BMP-2 half-life, (ii) reducing interactions between BMP-2 with its antagonist noggin, and (iii) modulating BMP2 distribution on the cell surface. Importantly, long-term supplementation of HS5 but not heparin greatly enhances BMP-2-induced bone formation in vitro and in vivo. These results show that bone marrow-derived HS effectively support bone formation, and suggests its applicability in bone repair by selectively facilitating the delivery and bioavailability of BMP-2.

The aim of the current study is to elucidate the mechanism of proline-rich tyrosine kinase 2 (Pyk2)-mediated cell proliferation and invasiveness in hepatocellular carcinoma (HCC) cells. Human HCC cell lines PLC and MHCC97L were stably transfected with either full-length Pyk2 or C-terminal non-kinase region of Pyk2 (PRNK). Functional studies on cell proliferation and invasion were conducted in vitro by colony formation assay, adhesion assay, migration assay and wound-healing assay. For the in vivo study, an orthotopic nude mice liver tumor model was applied to investigate the effects of Pyk2 overexpression on tumor growth and metastasis. Overexpression of Pyk2 in PLC cells resulted in an upregulation of colony formation (P = 0.021) and adhesion toward laminin (P = 0.018). Pyk2 promoted wound recovery by stimulation of actin stress fiber polymerization. In the in vivo study, transfection of PRNK in MHCC97L cells significantly decreased tumor volume (P = 0.001) and the incidence of lung metastasis (P = 0.014). Overexpression of Pyk2 promoted the activation of c-Src, formation of Pyk2/c-Src complex and activated the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-signaling pathway. Pyk2 upregulated the activation of ERK1/2 that is insensitive to MAPK/ERK kinase (MEK)1/2 inhibition. On the contrary, PRNK overexpression downregulated the activation of c-Src and ERK/MAPK-signaling pathways. Immunofluorescence staining showed that the focal adhesion localization of Pyk2 is a major determinant for c-Src and ERK/MAPK activation. In conclusion, our results showed that Pyk2 promoted cell proliferation and invasiveness by upregulation of the c-Src and ERK/MAPK-signaling pathways.

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Purpose: We aimed to investigate the effects of adiponectin on liver cancer growth and metastasis and explore the underlying mechanisms.Experimental Design: An orthotopic liver tumor nude mice model with distant metastatic potential was applied. Either Ad-adiponectin (1 × 10 8 ; treatment group) or Ad-luciferase (control group) was injected via portal vein after tumor implantation. Tumor growth and metastasis were monitored by Xenogen In vivo Imaging System. Hepatic stellate cell activation by α-smooth muscle actin staining, microvessel density by CD34 staining, macrophage infiltration in tumor tissue, and cell signaling leading to invasion, migration [Rho kinase (ROCK), IFN-inducible protein 10 (IP10), and matrix metalloproteinase 9], and angiogenesis [vascular endothelial growth factor (VEGF) and angiopoietin 1] were also compared. Tumor-nontumor margin was examined under electron microscopy. Direct effects of adiponectin on liver cancer cells and endothelial cells were further investigated by a series of functional studies.Results: Tumor growth was significantly inhibited by adiponectin treatment, accompanied by a lower incidence of lung metastasis. Hepatic stellate cell activation and macrophage infiltration in the liver tumors were suppressed by adiponectin treatment, along with decreased microvessel density. The treatment group had less Ki-67-positive tumor cells and downregulated protein expression of ROCK1, proline-rich tyrosine kinase 2, and VEGF. Tumor vascular endothelial cell damage was found in the treatment group under electron microscopy. In vitro functional study showed that adiponectin not only downregulated the ROCK/IP10/VEGF signaling pathway but also inhibited the formation of lamellipodia, which contribute to cell migration.Conclusion: Adiponectin treatment significantly inhibited liver tumor growth and metastasis by suppression of tumor angiogenesis and downregulation of the ROCK/IP10/matrix metalloproteinase 9 pathway. Clin Cancer Res; 16(3); 967-77. ©2010 AACR.Although surgical procedures such as liver resection and liver transplantation are first-line treatments for liver cancer, tumor recurrence and metastasis remain to be major problems affecting long-term disease-free survival. Therefore, development of novel adjuvant therapies targeting liver cancer growth, recurrence, and metastasis without obvious toxicity to the liver itself is essential.Adiponectin, a fat-derived hormone, has been shown to have a correlation with tumor development and prognosis (1, 2). Lower circulating levels of adiponectin have been found to be an independent predictor of colorectal cancer recurrence (3). Adiponectin can suppress hepatic stellate cell activation that plays an important role in angiogenesis. Hypoadiponectinemia accelerated liver tumor formation in a nonalcoholic steatohepatitis mouse model (4). It has been found that recombinant adiponectin not only significantly attenuated liver steatosis but also improved liver function by amelioration of inflammation (5) and rescued the marginal liver...

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CXCL10 over-expression, the distinct gene signature of acute-phase graft injury and tumor invasiveness in small-for-size liver grafts, may contribute to early tumor recurrence after liver transplantation. CXCL10 and its downstream signals may be potential therapeutic targets in the prevention of tumor recurrence after liver transplantation using small-for-size graft.

We previously demonstrated that the overexpression of homeoprotein Six1 in hepatocellular carcinoma (HCC) patients is associated with venous infiltration, advanced pathologic tumor metastasis (pTNM) stage and poor overall survival rate (Ng et al. Br J Cancer 2006;95:1050-5). In this study, short hairpin RNA (shRNA) interference approach was used to suppress the expression of Six1 in a metastatic HCC cell line MHCC97L. Stable transfectant MHCC97L-shSix1 carrying Six1-specific shRNA plasmid was established to downregulate Six1 expression to about 40% when compared with MHCC97L-Control. In vitro functional assays demonstrated that the growth rate and proliferation ability of MHCC97L-shSix1 cells were markedly decreased. Moreover, significant decrease of cell motility and invasiveness were observed in MHCC97L-shSix1 cells. Data from in vivo xenograft tumorigenesis model demonstrated that the size of tumor in MHCC97L-shSix1 group was dramatically reduced. Experimental and spontaneous metastasis models indicated that targeting Six1 suppression noticeably reduced the pulmonary metastasis in MHCC97L-shSix1 group. To identify Six1-regulated targets, cDNA microarray was employed to compare the expression profiles of MHCC97L-Control and MHCC97L-shSix1 cells. Twenty-eight downregulated and 24 upregulated genes with known functions were identified in MHCC97L-shSix1. The functions of these target genes are involved in diverse biological activities. Our data suggest that Six1 may be involved in regulation of proliferation and invasiveness of HCC; thus targeting suppression of Six1 is a viable option for treating HCC patients.Hepatocellular carcinoma (HCC) is one of the most malignant tumors in the world, causing more than 600,000 deaths per year. 1 Surgical treatments in terms of hepatic resection and orthotopic liver transplantation are frontline treatments for HCC, but the long-term disease-free survival remains unsatisfactory. 2,3 Tumor recurrence and metastases are the major causes of death in HCC patients after surgical treatments, 4,5 indicating the necessity of developing new therapeutic strategies targeting at tumor recurrence and metastases in HCC. Up to now, the molecular mechanisms of HCC metastasis remain unclear; hence, identification and characterization of novel metastasis-associated genes are indispensable for development of effective treatment of HCC patients.Homeoprotein Six1 belongs to a subfamily of the Six family of homeodomain-containing transcription factors that shares a lysine within the DNA-binding helix of the homeodomain. 6,7 Six1, located at 14q23 of the chromosome, is involved in early developments of diverse organs such as the brain, ear, eye, muscle and kidney. 7-11 Alteration of Six1 expression takes place in human breast cancer, Wilms' cancer, cervical cancer, ovarian cancer and rhabdomyosarcoma, indicating its possible contributions in the tumorigenicity of different cancers. [12][13][14][15][16] Six1 can transform the adult mammary gland to hyperplasia and highly aggressive tumor as well as...