Coagulation Factor Xa Promotes Solid Tumor Growth, Experimental Metastasis and Endothelial Cell Activation.

Hypercoagulable state is linked to cancer progression; however, the precise role of the coagulation cascade is poorly described. Herein, we examined the contribution of a hypercoagulative state through the administration of intravenous Coagulation Factor Xa (FXa), on the growth of solid human tumors and the experimental metastasis of the B16F10 melanoma in mouse models. FXa increased solid tumor volume and lung, liver, kidney and lymph node metastasis of tail-vein injected B16F10 cells. Concentrating on the metastasis model, upon coadministration of the anticoagulant Dalteparin, lung metastasis was significantly reduced, and no metastasis was observed in other organs. FXa did not directly alter proliferation, migration or invasion of cancer cells in vitro. Alternatively, FXa upon endothelial cells promoted cytoskeleton contraction, disrupted membrane VE-Cadherin pattern, heightened endothelial-hyperpermeability, increased inflammatory adhesion molecules and enhanced B16F10 adhesion under flow conditions. Microarray analysis of endothelial cells treated with FXa demonstrated elevated expression of inflammatory transcripts. Accordingly, FXa treatment increased immune cell infiltration in mouse lungs, an effect reduced by dalteparin. Taken together, our results suggest that FXa increases B16F10 metastasis via endothelial cell activation and enhanced cancer cell-endothelium adhesion advocating that the coagulation system is not merely a bystander in the process of cancer metastasis.

Curcumin-loaded nanoemulsion: a new safe and effective formulation to prevent tumor reincidence and metastasis.

Curcumin is widely considered beneficial to human health, but insolubility and instability greatly hamper reproducible exploitation of the advantageous traits. Here we report on the development, characterization and evaluation of a curcumin-loaded nanoemulsion (CUR-NEM) that is highly effective in preventing post-surgery tumor reincidence and metastasis. The method of fabrication utilized safe excipients and generated particles of 200 nm (PDI ≤ 0.2) with negative zeta potential (-30 mV) and a high yield of curcumin (95%), which can be converted by lyophilization to a dry powder. In vitro assays showed that CUR-NEM is safe in non-cancerous human cells (HEK-293T) and preferentially cytotoxic in gastric (AGS), colon (HT29-ATCC, HT29-US), breast (MDA-MB-231) and melanoma (B16F10) cells. In addition, in melanoma cells the nanoformulation increases intracellular curcumin accumulation and reactive oxygen species (ROS) formation, while preventing cell-migration and invasion. In vivo studies in C57BL/6 mice demonstrated that a single dose, applied topically to the wounded area after surgical excision of primary tumors formed upon subcutaneous injection of syngeneic B16F10 cells, was sufficient to completely prevent reincident tumor growth and spontaneous lung metastasis, while in untreated animals 70% reincidence and metastasis were observed. In vivo experiments also showed that the fluorescence signal due to curcumin was maintained at least 15 days after topical application of CUR-NEM, while when administered in DMSO the curcumin signal disappeared within 4 days. Importantly, the administration of a dose 22 times larger than that applied topically to animals after tumor surgery did not alter biochemical parameters. Due to the safety and efficacy of the formulation, we envisage it as ideal for topical application in cancer patients following surgery, to prevent tumor reincidence and metastasis. In addition, other routes of administration/protocols could also be proposed to treat/prevent malignant tumors in patients.

Gold nanoparticles as tracking devices to shed light on the role of caveolin-1 in early stages of melanoma metastasis.

AIM: To track early events during lung metastasis, we labeled cells expressing (B16F10CAV1) or lacking CAV1 (B16F10mock) with gold nanoparticles conjugated to the peptide TAT (AuNPs-PEG-TAT). METHODS: B16F10 expressing or lacking CAV1 were labeled with AuNPs-PEG-TAT. The physicochemical properties and cytotoxicity of these nanoparticles, as well as their effects on migration and invasiveness of B16F10 cells in vitro were evaluated. Ex vivo lung distribution of the labeled cells after tail vein injection into C57BL/6 mice was examined. RESULTS: AuNPs-PEG-TAT did not affect B16F10 viability, migration and invasiveness. The metastatic and tumorigenic capability of the labeled B16F10 was also not modified in comparison to unlabeled B16F10 cells. CAV1 expression favored the retention of B16F10 cells in the lungs of mice 2 h post injection, suggesting CAV1 promoted adherence to endothelial cells and transendothelial migration. CONCLUSIONS: We developed a protocol to label B16F10 cells with AuNPs-PEG-TAT that permits subsequent tracking of cells in mice. CAV1 overexpression was found to increase retention and transendothelial migration of B16F10 cells in the lung.