Browsing by Author "Quest, Andrew F.G."
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Item Biomimetic quantum dot-labeled B16F10 murine melanoma cells as a tool to monitor early steps of lung metastasis by in vivo imaging(2018) Díaz-García, Víctor Manuel; Guerrero, Simón; Díaz-Valdivia, Natalia; Lobos-González, Lorena; Kogan, Marcelo; Pérez-Donoso, José Manuel.; Quest, Andrew F.G.Background: Numerous studies have proposed the use of fluorescent semiconductor nanoparticles or quantum dots (QDs) as novel tools to label cells and tumors. However, QD applications are limited by their toxicity in biological systems and little is known about whether QDs affect the capacity of cancer cells to metastasize. Previously, we described the “biomimetic” synthesis of CdTe-QDs (QDs- glutathione [GSH]) with increased biocompatibility and the potential utility in labeling cells. Purpose: In order to determine the feasibility of using QDs-GSH as a tool for tracking tumor cells during early metastasis, we characterized here for the first time, the in vitro and in vivo effects of the incorporation of green or red biomimetic QDs-GSH into B16F10 cells, a syngeneic mouse melanoma line for metastasis assays in C57BL/6 mice. Methods: B16F10 cells were labeled with green or red biomimetic QDs-GSH in the presence or absence of n-acetylcysteine. Then, migration, invasion and proliferation of labeled B16F10 were evaluated in vitro. Finally, the B16F10 cells labeled with red QDs-GSH were used to monitor in vivo lung metastasis at early time points (5 minutes to 24 hours) or after 21 days in C57BL/6 mice. Results: We developed a methodology that allows obtaining QDs-GSH-labeled B16F10 cells (nearly 100% viable labeled cells), which remained viable for at least 5 days and migrated similarly to control cells. However, proliferation, invasion, and the capacity to form metastatic nodules in the lungs were severely attenuated. Fluorescence imaging revealed that distribution/accumulation of QDs-GSH-labeled B16F10 cells could be tracked following injection into C57BL/6 mice (syngeneic preclinical metastasis model) and that these cells preferentially accumulated in the perialveolar area in lungs as early as 5 minutes post-injection. Conclusion: The methodology described here represents a useful alternative for monitoring initial events during tumor cell metastasis.Item Src-family kinase inhibitors block early steps of caveolin-1-enhanced lungmetastasis by melanoma cells(2020) Ortiz, Rina; Díaz, Jorge; Díaz-Valdivia, Natalia; Martínez, Samuel; Simón, Layla; Contreras, Pamela; Lobos-González, Lorena; Guerrero, Simón; Leyton, Lisette; Quest, Andrew F.G.In advanced stages of cancer disease, caveolin-1 (CAV1) expression increases and correlates with increased migratory and invasive capacity of the respective tumor cells. Previous findings from our laboratory revealed that specific ECM-integrin interactions and tyrosine-14 phosphorylation of CAV1 are required for CAV1-enhanced melanoma cell migration, invasion and metastasis in vivo. In this context, CAV1 phosphorylation on tyrosine-14 mediated by non-receptor Src-family tyrosine kinases seems to be important; however, the effect of Src-family kinase inhibitors on CAV1-enhanced metastasis in vivo has not been studied. Here, we evaluated the effect of CAV1 and c-Abl overexpression, as well as the use of the Src-family kinase inhibitors, PP2 and dasatinib (more specific for Src/Abl) in lung metastasis of B16F10 melanoma cells. Overexpression of CAV1 and c-Abl enhanced CAV1 phosphorylation and the metastatic potential of the B16F10 murine melanoma cells. Alternatively, treatment with PP2 or dasatinib for 2 h reduced CAV1 tyrosine-14 phosphorylation and levels recovered fully within 12 h of removing the inhibitors. Nonetheless, pre-treatment of cells with these inhibitors for 2 h sufficed to prevent migration, invasion and trans-endothelial migration in vitro. Importantly, the transient decrease in CAV1 phosphorylation by these kinase inhibitors prevented early steps of CAV1-enhanced lung metastasis by B16F10 melanoma cells injected into the tail vein of mice. In conclusion, this study underscores the relevance of CAV1 tyrosine-14 phosphorylation by Src-family kinases during the first steps of the metastatic sequence promoted by CAV1. These findings open up potential options for treatment of metastatic tumors in patients in which Src-family kinase activation and CAV1 overexpression favor dissemination of cancer cells to secondary sites.