Cristina Borselli

Antiangiogenic activity of the endocannabinoid anandamide: Correlation to its tumor-suppressor efficacy†

Endocannabinoids are now emerging as suppressors of key cell‐signaling pathways involved in cancer cell growth, invasion, and metastasis. We have previously observed that the metabolically stable anandamide analog, 2‐methyl‐2′‐F‐anandamide (Met‐F‐AEA) can inhibit the growth of thyroid cancer in vivo. Our hypothesis was that the anti‐tumor effect observed could be at least in part ascribed to inhibition of neo‐angiogenesis. Therefore, the aim of this study was to assess the anti‐angiogenic activity of Met‐F‐AEA, to investigate the molecular mechanisms underlying this effect and whether Met‐F‐AEA could antagonize tumor‐induced endothelial cell sprouting. We show that Met‐F‐AEA inhibited bFGF‐stimulated endothelial cell proliferation, in a dose‐dependent manner, and also induced apoptosis, both effects reliant on cannabinoid CB1 receptor stimulation. Analyzing the signaling pathways implicated in angiogenesis, we observed that the bFGF‐induced ERK phosphorylation was antagonized by Met‐F‐AEA, and we found that p38 MAPK was involved in Met‐F‐AEA‐induced apoptosis. Moreover, Met‐F‐AEA was able to inhibit bi‐dimensional capillary‐like tube formation and activity of matrix metalloprotease MMP‐2, a major matrix degrading enzyme. Importantly, we demonstrated that Met‐F‐AEA is also functional in vivo since it inhibited angiogenesis in the chick chorioallantoic neovascularization model. Finally, Met‐F‐AEA inhibited tumor‐induced angiogenesis in a three‐dimensional model of endothelial and thyroid tumor cell (KiMol) spheroids co‐cultures in different 3‐D polymeric matrices that resemble tumor microenvironment and architecture. Thus, our results suggest that anandamide could be involved in the control of cancer growth targeting both tumor cell proliferation and the angiogenic stimulation of the vasculature. J. Cell. Physiol. 211: 495–503, 2007.

Bioactivation of collagen matrices through sustained VEGF release from PLGA microspheres.

The success of any tissue engineering implant relies upon prompt vascularization of the cellular construct and, hence, on the ability of the scaffold to broadcast specific activation of host endothelium and guide vessel ingrowth. Vascular endothelial growth factor (VEGF) is a potent angiogenic stimulator, and if released in a controlled manner it may enhance and guide scaffold vascularization. Therefore, the aim of this work was to realize a scaffold with integrated depots able to release VEGF in a controlled rate and assess the ability of this scaffold to promote angiogenesis. VEGF-loaded poly(lactide-co-glycolide) (PLGA) microspheres were produced and included in a collagen scaffold. The release of VEGF from microspheres was tailored to be sustained over several weeks and occurred at a rate of approximately 0.6 ng/day per mg of microspheres. It was found that collagen scaffolds bioactivated with VEGF-loaded microspheres strongly enhanced endothelial cell activation and vascular sprouting both in vitro and in vivo as compared with a collagen scaffold bioactivated with free VEGF. This report demonstrates that by finely tuning VEGF release rate within a polymeric scaffold, sprouting of angiogenic vessels can be guided within the scaffolds interstices as well as broadcasted from the host tissues.

Human papilloma virus 16 E7 oncogene does not cooperate with RET/PTC 3 oncogene in the neoplastic transformation of thyroid cells in transgenic mice

We have previously reported that the thyroid-targeted expression of the RET/PTC3 oncogene (Tg-RET/PTC3) in transgenic mice induces follicular hyperplasia with papillary architecture, resulting in a modest increase of the thyroid gland volume, followed by the appearance of papillary carcinomas in approximately 1-year-old animals. In order to analyze the genetic alterations that may cooperate with RET/PTC3 in the development or progression of thyroid tumors, we interbred Tg-RET/PTC3 mice with Tg-E7 transgenic mice, which express the E7 oncogene of the human papilloma virus 16 in thyroid cells. Tg-E7 mice develop large colloid goiters with small papillae and well-differentiated thyroid carcinomas in older animals. Here we show that thyroid lesions in Tg-RET/PTC3-Tg-E7 double transgenics were morphologically different from those occurring in Tg-RET/PTC3 mice, while they were virtually indistinguishable from those occurring in Tg-E7 mice. In addition, the coexpression of RET/PTC3 and E7 oncogenes neither enhanced the malignant phenotype nor reduced the latency period of thyroid lesions with respect to parental transgenic lines. We conclude that the coexpression of RET/PTC3 and E7 lacks any cooperative effect in the neoplastic transformation of thyroid cells and that the E7-induced thyroid phenotype is dominant with respect to the RET/PTC3 one.

Cellular mechanosensory: tissue engineering material design

Is well known that complex biological processes such as development, tissue function, immune response, and wound healing require the orchestration of a variety of biochemical signals, primarily achieved by active cross-talk between cells and their environment. For this reason, in the last ten years the research interest have been focused on the study and design of novel materials able to stimulate, control and promote cell growth and remodelling, to enhance the recovery and repair of tissue functions. On the contrary the influence of the structure of the material on the mechanism of cellular function has never been addressed in a specific manner. The aim is to study the influence of the microstructure of different materials on the cell viability and motility and to define not only the chemical but also the physical characteristics of an engineered gel.