Journal Article

MMPSense; in vivo imaging; matrix metalloproteinases; stroke

Matrix metalloproteinases (MMPs) have been implicated in the pathophysiology of cerebral ischemia. In this study, we explored whether MMP activity can be visualized by noninvasive near-infrared fluorescence (NIRF) imaging using an MMP-activatable probe in a mouse model of stroke. C57Bl6 mice were subjected to transient middle cerebral artery occlusion (MCAO) or sham operation. Noninvasive NIRF imaging was performed 24 h after probe injection, and target-to-background ratios (TBRs) between the two hemispheres were determined. TBRs were significantly higher in MCAO mice injected with the MMP-activatable probe than in sham-operated mice and in MCAO mice that were injected with the nonactivatable probe as controls. Treatment with an MMP inhibitor resulted in significantly lower TBRs and lesion volumes compared to injection of vehicle. To test the contribution of MMP-9 to the fluorescence signal, MMP9-deficient (MMP9(-/-)) mice and wild-type controls were subjected to MCAO of different durations to attain comparable lesion volumes. TBRs were significantly lower in MMP9(-/-) mice, suggesting a substantial contribution of MMP-9 activity to the signal. Our study shows that MMP activity after cerebral ischemia can be imaged noninvasively with NIRF using an MMP-activatable probe, which might be a useful tool to study MMP activity in the pathophysiology of the disease.

Journal Article

MDA-MB-231-luc-D3H2Ln, D3H2Ln, Bioware, IVIS

Metastases, and not the primary tumor from which they originate, are the main reason for mortality from carcinoma. Although the molecular mechanisms behind metastasis are poorly understood, it is clear that epigenetic dysregulation at the level of microRNA expression is a key characteristic of the metastatic process that can be exploited for therapy. Here, we describe an miRNA-targeted therapeutic approach for the prevention and arrest of lymph node metastasis. Therapy relies on the inhibition of the pro-metastatic microRNA-10b. It is delivered to primary and lymph node metastatic tumor cells using an imaging-capable nanodrug that is designed to specifically home to these tissues. Treatment of invasive human breast tumor cells (MDA-MB-231) with the nanodrug in vitro downregulates miR-10b and abolishes the invasion and migration of the tumor cells. After intravenous delivery to mice bearing orthotopic MDA-MB-231-luc-D3H2LN tumors, the nanodrug accumulates in the primary tumor and lymph nodes. When treatment is initiated before metastasis to lymph nodes, metastasis is prevented. Treatment after the formation of lymph node metastases arrests the metastatic process without a concomitant effect on primary tumor growth raising the possibility of a context-dependent variation in miR-10b breast oncogenesis.Oncogene advance online publication, 14 May 2012; doi:10.1038/onc.2012.173.

Journal Article

Actins; Animals; B16-F10-luc-G5; Bioware; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cofilin 1; Cytoskeleton; Female; Humans; Immunoblotting; Immunoprecipitation; Male; Mammary Neoplasms, Experimental; MDA-MB-231-D3H2LN cells; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphorylation; Protein Binding; Protein Kinases; Protein Phosphatase 2; Protein-Serine-Threonine Kinases; RNA Interference; Transplantation, Heterologous

Metastasis leads to the death of most cancer patients, and basal breast cancer is the most aggressive breast tumor type. Metastasis involves a complex cell migration process dependent on cytoskeletal remodeling such that targeting such remodeling in tumor cells could be clinically beneficial. Here we show that Hormonally Up-regulated Neu-associated Kinase (HUNK) is dramatically down-regulated in tumor samples and cell lines derived from basal breast cancers. Reconstitution of HUNK expression in basal breast cancer cell lines blocked actin polymerization and reduced cell motility, resulting in decreased metastases in two in vivo murine cancer models. Mechanistically, HUNK overexpression sustained the constitutive phosphorylation and inactivation of cofilin-1 (CFL-1), thereby blocking the incorporation of new actin monomers into actin filaments. HUNK reconstitution in basal breast cancer cell lines prevented protein phosphatase 2-A (PP2A), a phosphatase putatively acting on CFL-1, from binding to CFL-1. Our investigation of HUNK suggests that the interaction between PP2A and CFL-1 may be a target for antimetastasis therapy, particularly for basal breast cancers.

Journal Article

Animals; Bioware; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; GRB2 Adaptor Protein; Humans; Mice; Mice, SCID; Microscopy, Fluorescence; Neoplasm Metastasis; Neoplasm Transplantation; PC-3M-luc; Protein Binding; Protein Structure, Tertiary; Tetrazolium Salts; Thiazoles

Metastasis, the primary cause of death in most forms of cancer, is a multistep process whereby cells from the primary tumor spread systemically and colonize distant new sites. Blocking critical steps in this process could potentially inhibit tumor metastasis and dramatically improve cancer survival rates; however, our understanding of metastasis at the molecular level is still rudimentary. Growth factor receptor binding protein 2 (Grb2) is a widely expressed adapter protein with roles in epithelial cell growth and morphogenesis, as well as angiogenesis, making it a logical target for anticancer drug development. We have previously shown that a potent antagonist of Grb2 Src homology-2 domain-binding, C90, blocks growth factor-driven cell motility in vitro and angiogenesis in vivo. We now report that C90 inhibits metastasis in vivo in two aggressive tumor models, without affecting primary tumor growth rate. These results support the potential efficacy of this compound in reducing the metastatic spread of primary solid tumors and establish a critical role for Grb2 Src homology-2 domain-mediated interactions in this process.

Journal Article

SKOV3-luc-D3, SKOV3-luc, IVIS, Ovarian Cancer, Animals; Antineoplastic Agents, Phytogenic/*administration & dosage; Cell Line, Tumor; Drug Carriers/*chemical synthesis/chemistry/therapeutic use; Drug Delivery Systems/*methods; Female; Flow Cytometry; Humans; Integrin alpha Chains/metabolism; Mice; Mice, Nude; Micelles; Microscopy, Confocal; Nanoparticles/chemistry/therapeutic use; Ovarian Neoplasms/*drug therapy; Paclitaxel/*administration & dosage; Peptides/chemical synthesis/therapeutic use; Polyethylene Glycols/chemistry

Micellar nanoparticles based on linear polyethylene glycol (PEG) block dendritic cholic acids (CA) copolymers (telodendrimers), for the targeted delivery of chemotherapeutic drugs in the treatment of cancers, are reported. The micellar nanoparticles have been decorated with a high-affinity “OA02” peptide against alpha-3 integrin receptor to improve the tumor-targeting specificity which is overexpressed on the surface of ovarian cancer cells. “Click chemistry” was used to conjugate alkyne-containing OA02 peptide to the azide group at the distal terminus of the PEG chain in a representative PEG(5k)-CA(8) telodendrimer (micelle-forming unit). The conjugation of OA02 peptide had negligible influence on the physicochemical properties of PEG(5k)-CA(8) nanoparticles and as hypothesized, OA02 peptide dramatically enhanced the uptake efficiency of PEG(5k)-CA(8) nanoparticles (NP) in SKOV-3 and ES-2 ovarian cancer cells via receptor-mediated endocytosis, but not in alpha-3 integrin-negative K562 leukemia cells. When loaded with paclitaxel, OA02-NPs had significantly higher in vitro cytotoxicity against both SKOV-3 and ES-2 ovarian cancer cells as compared with nontargeted nanoparticles. Furthermore, the in vivo biodistribution study showed OA02 peptide greatly facilitated tumor localization and the intracellular uptake of PEG(5k)-CA(8) nanoparticles into ovarian cancer cells as validated in SKOV3-luc tumor-bearing mice. Finally, paclitaxel (PTX)-loaded OA02-NPs exhibited superior antitumor efficacy and lower systemic toxicity profile in nude mice bearing SKOV-3 tumor xenografts, when compared with equivalent doses of nontargeted PTX-NPs as well as clinical paclitaxel formulation (Taxol). Therefore, OA02-targeted telodendrimers loaded with paclitaxel have great potential as a new therapeutic approach for patients with ovarian cancer.