Background: Disintegrins from snake venoms bind with high specificity cell surface integrins,
which are important pharmacological targets associated with cancer development and progression.
Objective: In this study, we isolated a disintegrin from the Porthidium lansbergii lansbergii venom and
evaluated its antitumoral effects on breast cancer cells.
Methods: The isolation of the disintegrin was performed on RP-HPLC and the inhibition of platelet aggregation
was evaluated on human platelet-rich plasma. The inhibition of cell adhesion was also evaluated
in vitro on cultures of cell lines by the MTT method as well as the inhibition of breast cancer cell
migration by the wound healing assay. The binding of the disintegrin to integrin subunits was verified by
flow cytometry and confocal microscopy. Finally, inhibition of angiogenesis was assessed in vitro on
HUVEC cells and the concentration of VEGF was measured in the cellular supernatants.
Results: The disintegrin, named Lansbermin-I, is a low molecular weight protein (< 10 kDa) that includes
an RGD on its sequence identified previously. Lansbermin-I showed potent inhibition of ADP and
collagen-induced platelet aggregation on human plasma and also displayed inhibitory effects on the adhesion
and migration of breast cancer MCF7 and MDA-MB 231cell lines, without affecting nontumorigenic
breast MCF-10A and lung BEAS cells. Additionally, Lansbermin-I prevented MCF7 cells to
adhere to fibronectin and collagen, and also inhibited in vitro angiogenesis on human endothelial HUVEC
Conclusion: Our results display the first report on the antitumor and anti-metastatic effects of an RGDdisintegrin
isolated from a Porthidium snake venom by possibly interfering with α2 and/or β1-containing
integrins. Thus, Lansbermin-I could be an attractive model to elucidate the role of disintegrins against
breast cancer development.