RECK in osteosarcoma: a novel role in tumour vasculature and inhibition of tumorigenesis in an orthotopic model.

BACKGROUND: Targeted therapy in osteosarcoma (OS) is needed to improve patient outcomes. Human RECK may have a role because it inhibits cancer invasion and regulates angiogenesis. This study aimed to characterize RECK expression in human OS, to examine in vitro effects of RECK on vascular endothelium and OS cell behavior, and to analyze the effect of RECK on OS grown orthotopically in nude mice. METHODS: RECK was examined in human OS samples. Interactions between RECK and VEGF were studied in tissue and cells. RECK transfection was used to study its effects on vascular endothelial (HMEC-1) and OS (SaOS-2) cell behavior in vitro and in vivo. SaOS-2 co-culture with RAW 246.7-derived osteoclasts on osteoslides was used to assess effects on osteoclast activity. RESULTS: RECK was absent from OS cells but was expressed in tumor vessel endothelium. Via microarray analysis, RECK mRNA was elevated in samples with low proliferative activity, a trend most evident in poorly differentiated samples. VEGF induced RECK expression in HMEC-1. RECK transfection inhibited HMEC-1 invasion and induced thicker, although more numerous, tube formation. RECK inhibited SaOS-2 invasion, proliferation, colony formation, and osteoclast activity but supported SaOS-2 adhesion to collagen I. In vivo, RECK inhibited SaOS-2 tumor growth, bone destruction, and consequent metastasis. CONCLUSIONS: RECK expression is downregulated in highly proliferative OS but is present in tumor vessels and upregulated in endothelium by VEGF. RECK inhibits invasion and tumorigenic properties in SaOS-2, as confirmed in vivo. Further testing of RECK delivery in OS is warranted.

Dz13 induces a cytotoxic stress response with upregulation of E2F1 in tumor cells metastasizing to or from bone.

The oligonucleotide Dz13 is a DNA enzyme (deoxyribozyme) that cleaves c-Jun mRNA. It has efficacious effects against tumors directly, is active against tumor-induced angiogenesis, inhibits neointima formation after arterial injury, and controls inflammatory responses. The off-target effects of Dz13 may in fact be driving some of these potentially therapeutic effects, though no mechanisms have been clearly defined in target cells. To this end, we here show that when a panel of human tumor cells that naturally propagate in bone are challenged with Dz13, the tumor suppressor E2F1 is upregulated regardless of cellular p53 status. The piddosomal components, p53-induced protein with a death domain and caspase-2, were translocated to the nucleus when deoxyribozymes were incubated with cells, but RIP associated Ich-1/CED homologous protein with death domain levels increased throughout the cell with either Dz13 or its scrambled control oligonucleotide. In response to Dz13-mediated cytotoxicity, cells upregulated levels of ERK, Akt, and p38. Summarily, these results suggest a cytotoxic stress (resembling DNA damage) response of tumor cells to Dz13, which induces apoptosis via the activation of inhibitor of caspase-activated deoxyribonuclease and protein kinase C delta. In vivo, in tumor-in-bone orthotopic and clinically relevant models for prostate and breast cancer metastasis, and a novel spontaneously metastasizing model for osteosarcoma (OS), Dz13 decreased growth in bone, and also metastasis for OS. This new model for OS was assessed to be clinically relevant in its expression of typical bone markers, osteopontin and osteocalcin. These results provide an off-target mechanism for Dz13 function, but this may be useful therapeutically against tumors.

Dz13, a c-jun DNAzyme, is a potent inducer of caspase-2 activation.

Signaling pathways for caspase-2-mediated apoptosis are poorly defined. This is partially due to a lack of a reproducible stimulus to trigger caspase-2 activation. We present the oligonucleotide Dz13, a DNA enzyme that cleaves c-Jun mRNA and is capable of inhibiting various model tumors in mice, which potently induces caspase-2 resulting in apoptosis in a panel of tumor cell lines. Dz13-mediated cell death occurred even in the absence of known caspase-2 molecular partners in p53-induced protein with a death domain, RIP-associated Ich-1/CED homologous protein with death domain, or DNA-dependent protein kinase catalytic subunit, or other caspases in cell lines of breast cancer, prostate cancer, osteosarcoma, and liposarcoma. z-VDVAD-fmk, caspase-2(-/-) mouse embryonic fibroblasts and siRNA silencing of caspase-2 in tumor cells abrogated Dz13-mediated cell death. In an orthotopic tumor model, expression of caspase-2 increased as the tumor metastasized and caspase-2 expression was sporadic in patient tumor specimens. These findings provide hope that Dz13, and other agents that evoke activation of caspase-2, may be therapeutic clinically.

Myoepithelioma within the carpal tunnel: a case report and review of the literature.

Myoepitheliomas of the extremity are rare and usually benign, while a minority display malignant features. This case demonstrates the diagnosis and management of myoepithelioma within the carpal tunnel. Clinical and radiological tumour features were evaluated. Hematoxylin and eosin stained tumour sections were examined, and immunohistochemistry was performed. Histology revealed a nodular mass of epithelioid cells in clusters within a myxoid/chondroid stroma. No mitoses were noted. Cytokeratins, neuron-specific enolase, synaptophysin, glial fibrillary acidic protein, and S100 were positive on immunohistochemistry. A literature review revealed very few prior reports of myoepithelioma in the wrist, and limited data concerning any relationship between recurrence and quality of surgical margins. In this case, wide local excision would have significantly compromised dominant hand function, and therefore a marginal excision was deemed appropriate in the context of bland histological features. Surgical margins noted in future case reports will aid clinical decision making.

Involvement of c-jun in human liposarcoma growth: supporting data from clinical immunohistochemistry and DNAzyme efficacy.

c-jun has been found to be upregulated in a variety of cancers. Recently, this oncogene has also been implicated in liposarcoma (LS) progression. c-jun knockdown mediated by a deoxyribozyme induced apoptosis in LS cells via evoking caspase-10, but not the Fas/FasL pathway. A novel orthotopic model for LS was established in the hindlimb of mice using human cells to extend the evaluation of effects of c-jun knockdown in vivo. Tumor take in vivo was 100%, with growths resembling high grade aggressive LS. The c-jun deoxyribozyme inhibited the growth of LS in this model. Clinically, downregulation of c-jun may proffer an improved treatment outcome for liposarcoma. The new model for LS described here will enable better testing of agents with therapeutic potential against LS.

Biocompatible properties of surgical mesh using an animal model.

AIM: To study the biocompatibility of surgical meshes for use in pelvic reconstructive surgery using an animal model. METHODS: Eight different types of mesh: Atrium, Dexon, Gynemesh, IVS tape, Prolene, SPARC tape, TVT tape and Vypro II, were implanted into the abdominal walls of rats for 3 months' duration. Explanted meshes were assessed, using light microscopy, for parameters of rejection and incorporation. RESULTS: Type 1 (Atrium, Gynemesh, Prolene, SPARC and TVT) and type 3 (Vypro II, Dexon and IVS) meshes demonstrated different biocompatible properties. Inflammatory cellular response and fibrosis at the interface of mesh and host tissue was most marked with Vypro II and IVS. All type 1 meshes displayed similar cellular responses despite markedly different mesh architecture. CONCLUSIONS: The inflammatory response and fibrous reaction in the non-absorbable type 3 meshes tested (IVS and Vypro II) was more marked than the type 1 meshes. The increased inflammatory and fibrotic response may be because of the multifilamentous polypropylene components of these meshes. Material and filament composition of mesh is the main factor in determining cellular response.