Widely used to promote cardiovascular health, grape seed extract (GSE) contains high levels of proanthocyanidins with strong antioxidant properties. In preliminary in vitro studies, we identifie a variety of GSE-mediated anti-neoplastic mechanisms, including induction of apoptosis and inhibition of cell proliferation via down-regulation of specific microRNA (miRNA). We now aim to translate these in vitro findings and set the stage for future clinical trial. A standardized GSE preparation complexed with soy phospholipids into phytosomes to improve bioavailability (Leucoselect) is available over the counter. Leucoselect has been shown to improve the total antioxidant capacity of plasma and reduce LDL susceptibility to oxidative stress in heavy smokers, but the potential of Leucoselect against lung cancer has never been evaluated. We therefore hypothesize that oral administration of Leucoselect will exert antineoplastic effects and favorably modulate mechanisms associated with lung cancer.
Three specific aims are proposed:
Aim #1 : To determine the maximum tolerated dose (MTD), pharmacokinetics (PK)/ pharmacodynamics (PD), and anti-cancer effects of Leucoselect in mouse models. A dose range finding study with leucoselect will be conducted in nude mice given varying doses via oral gavage. Blood and lung samples will be obtained to determine PK of grape seed procyanidin (GSP) and metabolites as surrogate markers of bioavailability of GSE (systemically and in the lungs), and to establish the MTD over 2 weeks treatment duration.
Aim #1. 1: To determine the bioactivity of oral Leucoselect at the targeted organ site using a novel co-culture system of snap frozen mouse lung sections with human lung neoplastic cells. Bioactivity in the lungs will be assessed by comparing lung tissue sections from control vs. Leucoselect treated mice co-cultured with the human nonsmall cell lung cancer (NSCLC) cell line, A549, and the bronchial premaligant cell line, 1198. The effects of varying GSE doses on proliferation and apoptosis in co-cultured A549 and 1198 cells will be correlated to GSP and metabolites levels.
Aim #2 : To determine the anti-caner effects of Leucoselect on lung cancer xenograft models. Varying doses of Leucoselect based on MTD will be administered via oral gavage to mice bearing subcutaneous NSCLC xenografts for up to 8 weeks, with serial collections of plasma, lung tissues and tumor xenografts from each treatment group. The anticancer effects will be determined by tumor growth delay or time to reach maximum tumor volume, proliferation (Ki-67) and apoptotic (cleaved caspase 3) indices, and correlated to GSP levels in plasma, lung tissue, and xenograft tumor samples.
Aim #2. 1: To further characterize and correlate the mechanistic effects of Leucoselect against lung cancer in xenograft models. The mechanistic effects of GSE will be measured by modulations of: 1) COX-2 expression and PGE2 production, and 2) Additional markers of inflammations: 15(S)-hydroxy-eicosatetraenoic acid (15-HETE), interleukin (IL)-6, IL-10, and 3) mir-19a, -19b and -106b levels, 4) cancer relevant, pathway specific gene expression profiles (GEP), 5) microRNA expression, and 6) common biomarkers of cancerization such as p53, p27, p21 and p16, in various sample types.
Aim #3 : To validate and characterize the roles of mir-19a, mir-19b, and mir-106b in mediating the anti- neoplastic effects of Leucoselect and examine the potential of plasma mir-19a, mir-19b, mir-106b as SEBM for therapeutic monitoring. In our preliminary in vitro studies, we have identified significant down-regulation of 3 oncomirs: mir-19a, mir-19b, and mir-106b in NSCLC and 1198 cell lines by GSE. These miRNAs are among the major plasma miRNAs identified to be predictors of lung cancer development. Therefore, we will measure these miRNA levels in plasma obtained from xenograft models to determine their utility as surrogate endpoint biomarkers (SEBM). IMPACT: Findings from the study will provide important insights into the feasibility and mechanistic effects of GSE against lung cancer, help identify SEBM and pave the way for clinical trials in the near future. The potential gain for the management and prevention of lung cancer is enormous.
Lung cancer is the leading cause of cancer death in the country, surpassing deaths caused by colorectal, prostate and breast cancers combined. The lack of effective therapy provides the impetus to search for alternative, anti-neoplastic and chemopreventive agents. Grape seed extract (GSE) contains high level of proanthocyanidins with strong antioxidant properties and is used to promote cardiovascular health. It has also been reported as a natural cyclooxygenase-2 (COX-2) inhibitor. Based on our encouraging in vitro findings, the purpose of this new Merit Review proposal is to evaluate the in vivo anti-neoplastic properties of Leucoselect, a specially formulated GSE phytosome with enhanced bioavailability, in mouse models of lung cancer, determine its pharmacokinetics and pharmacodynamics against lung cancer, identify suitable surrogate endpoint biomarkers and set the stage for clinical trials in the near future.