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

Abstract

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.

Proanthocyanidins Inhibit In vitro and In vivo Growth of Human Non–Small Cell Lung Cancer Cells by Inhibiting the Prostaglandin E2 and Prostaglandin E2 Receptors

“…Recently, we found that dietary GSPs resulted in the significant inhibition of the growth of human non-small cell lung cancer (NSCLC) cell xenografts in nude mice and that this was associated with the inhibition of lung tumor cell proliferation and the inhibition of angiogenic factors (28). In the present study, we investigated the mechanism responsible for the inhibition of lung cancer cell proliferation using in vitro and in vivo models.…”

“…The effect of GSPs on the proliferative capacity of the cells was determined using the MTT assay as previously described (28). The effect of GSPs on cell viability was assessed as the percent cell viability compared with vehicle-treated control cells, which were arbitrarily assigned 100% viability.…”

“…GSP-induced apoptosis of the human NSCLC cells was determined by flow cytometry using the Annexin V-conjugated Alexa Fluor488 (Alexa488) Apoptosis Detection kit following the instructions of the manufacturer, and as described by us (28,29). Briefly, after overnight serum starvation, cells were treated with varying concentrations of GSPs for 48 h. The cells were then harvested, washed in PBS, and incubated with Alexa488 and propidium iodide in the dark at room temperature.…”

“…Following treatment of the NSCLC cells with or without GSPs, the cells were harvested, washed with cold PBS, and lysed with ice-cold lysis buffer supplemented with protease inhibitors, as detailed previously (28,29). Lysates of tumor xenografts were prepared similarly.…”

“…(28). Briefly, the female athymic nude mice (6-to 7-wk-old) used in these studies were purchased from the National Cancer Institute.…”