Adenovirus‐mediated expression of TIMP‐1 and TIMP‐2 in bone inhibits osteolytic degradation by human prostate cancer

Abstract

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play critical roles in the pathogenesis of human cancers. Clinical trials using synthetic small molecule MMP inhibitors have been carried out but with little success. Tissue inhibitors of metallopro-teinases (TIMPs) are endogenous inhibitors that block the extrac-ellular matrix-degrading activity of MMPs. Here, we investigated the possibilities of genetically modifying human bones with TIMPs to create a high-TIMP bone microenvironment, which is hostile to metastatic prostate cancer cells using adenovirus-mediated gene transfer technology and SCID-hu end-organ coloniza-tion mouse model. Two strategies were used to achieve bone-specific TIMP expression: (i) ex vivo bone adenoviral infection followed by in vivo bone implantation; and (ii) ex vivo BMS cell infection followed by injection into in vivo implanted human fetal bones. PC-3 prostate cancer cells were injected into human fetal bones 4 weeks after implantation in SCID mice. In vitro, adenovi-rus-mediated expression of TIMP-1 or TIMP-2 in bone fragments inhibited MMP-2 activity, bone turnover and prostate cancer cell-induced proteolytic degradation as determined by gelatin zymography, calcium measurement and DQ protein quenched fluorescence assay, respectively. In vivo, immunohistochemistry confirmed TIMP-2 expression in AdTIMP-2-infected bone implants 4 weeks after implantation in SCID mice. Mice receiving AdTIMP-treated bone fragments showed significantly reduced PC-3-induced osteolysis, osteoclast recruitment and bone turnover in the implanted bones. We propose that adenoviral gene transfer of TIMP-1 and TIMP-2 can prevent the proteolytic activity of prostate cancer cells in bone and that enhancing anti-proteolytic defense mechanisms in target organs represents a promising form of prostate cancer gene therapy. ' 2007 Wiley-Liss, Inc. Key words: prostate cancer; matrix metalloproteinases; tissue inhibitors of metalloproteinases; recombinant adenovirus; bone metastasis; SCID-hu mouse model Prostate cancer (PCa) is the most common type of cancer in men and the second leading cause of cancer-related deaths in men in the US. 1 Metastases to bone, which occur early in the course of disease, are responsible for most of the morbidity associated with this disease. 2 Currently available therapeutic modalities for PCa, such as surgery, androgen ablation, radiation and chemotherapy, are mostly palliative and have failed to cure patients with advanced disease. 3 Therefore, new approaches to treat PCa bone metastasis are urgently needed. It has been reported that therapies that specifically target bone metastases using bone-homing radio-nuclides (such as strontium-89) alone or in combination with chemotherapy may extend survival in PCa patients in randomized clinical trials. 4,5 However, while the results are not conclusive and need further confirmation, dose-limiting toxicity of the radionu-clides remains a problem that hampers their further application. Recently, improved understanding of molecular pathways...

Genes and pathways identified in thyroid carcinoma based on bioinformatics analysis

“…Importantly, TIMP1 up-regulation in PTC was reported recently [34]. Earlier studies indicated that TIMP1 displayed anti-cancer activities [35,36], however, recent studies demonstrated a paradoxical protumor effect of TIMP1 [31,37]. In the present study, TIMP1 was up-regulated in PTC and ATC, while down-regulated in FTC, which was in accordance with the findings above.…”

SKI-606 (Bosutinib) Blocks Prostate Cancer Invasion, Growth, and Metastasis In vitro and In vivo through Regulation of Genes Involved in Cancer Growth and Skeletal Metastasis

“…TIMPs balance the activity of proteases in cooperation with additional factors within the tumor microenvironment but may also promote tumor metastases (36). Another study reports that decreasing the expression of TIMPs by gene transfer or by chemical agents results in decreased tumor metastases (37). Repression of several other genes, such as BMP-2, BMP-6, IL-8, and TGF-β, by SKI-606 is most likely beneficial.…”

Inhibition of tumor growth and induction of apoptosis in prostate cancer cell lines by overexpression of tissue inhibitor of matrix metalloproteinase-3

“…37,38 Most of them use recombinant adenoviruses or lentiviruses, 39,40 but because of the possibility of recombination with wildtype adenovirus and the antiviral immune response, these approaches have been limited to research use. 41 More recently, electroporation has been applied in vivo and shown to be potentially safe for clinical use.…”