Grape Seed Proanthocyanidins Inhibit the Growth of Human Non-Small Cell Lung Cancer Xenografts by Targeting Insulin-Like Growth Factor Binding Protein-3, Tumor Cell Proliferation, and Angiogenic Factors

Purpose: Lung cancer is a leading cause of cancer-related deaths worldwide. Here, we assessed the chemotherapeutic effect of grape seed proanthocyanidins (GSPs) on human non-small cell lung cancer (NSCLC) cells in vitro and in vivo using a tumor xenograft model. Experimental Design: The effects of GSPs on human NSCLC cell lines in terms of cellular proliferation were determined. The chemotherapeutic effects of a GSP- supplemented AIN76A control diet fed to nude mice bearing tumor xenografts (A549 and H1299) were evaluated in terms of biomarkers of cell proliferation and angiogenesis and on insulin-like growth factor binding protein-3 using immunohistochemical detection, ELISA, and Western blotting. Results: In vitro treatment of NSCLC cells with GSPs resulted in inhibition of cellular proliferation. Administration of GSPs (0.1%, 0.2%, and 0.5%, w/w) as a supplement of an AIN76A control diet resulted in a dose-dependent inhibition of the growth of NSCLC (A549 and H1299) tumor xenografts in athymic nude mice (25-76%; P < 0.05-0.001). The growth-inhibitory effect of GSPs on the NSCLC xenograft tumors was associated with the enhancement of the levels of insulin-like growth factor binding protein-3 in the tumor microenvironment and plasma and antiproliferative, antiangiogenic, and proapoptotic effects. Conclusions: This preclinical study reveals for the first time that dietary GSPs have the ability to inhibit the growth of human NSCLC tumor xenografts grown in vivo in athymic nude mice. More studies are needed to develop GSPs as a pharmacologically safe agent for the prevention of lung cancer in humans.