In this study the effects of crude garlic extract (CGE) on four human cancer cell lines; HepG2 (hepatic cancer cells), Caco-2 (colon cancer cells), MCF-7 (breast cancer cells), PC-3 (prostate cancer cells) and mouse macrophageal cell line TIB-71 were studied in vitro. The effects of CGE on cell cycle arrest and induction of apoptosis in PC-3 cells were also examined. A significant inhibition of cell growth was observed in HepG2, MCF-7, TIB-71 and PC-3 by 90% and Caco-2 by 60% when treated with 1 μg/ml, 0.5 μg/ml, and 0.25 μg/ml of CGE. A decrease in cell growth (60% HepG2, 20% Caco-2, 58% PC-3 and 55% MCF-7) was observed when the cells were treated with 0.125 μg/ml. Furthermore, an increase (90%) in cell growth inhibition was observed in Caco-2 cells when co-cultured with TIB-71 and treated with 1 μg/ml, 0.5 μg/ml, and 0.25 μg/ml of CGE. CGE also induced cell cycle arrest in PC-3 cells when treated with 0.5 μg/ml. A four-fold increase in caspase activation was seen when PC-3 cells were treated with 1 μg/ml of CGE.

The goal of study 2 was to formulate paclitaxel into a self assembling nanoemulsion (SANE) formulation that does not contain Cremophor EL and ethanol and demonstrate that paclitaxel SANE formulation inhibited cell proliferation of MCF-7 breast (80%), CCL-221 colon (60%), and P10.05 and PL-45 pancreatic cell lines (60%) compared to a blank nanoemulsion. In addition, nanoemulsion of paclitaxel with a mean particle size of 20 nm dramatically reduced zeta potential and showed up to 12 fold greater apoptosis in the PL-45 pancreatic cancer cell line compared to the blank nanoemulsion.

In a follow up study to this previous study, the third study was set up to establish a novel delivery system for an anti cancer drug such as paclitaxel that will not only be Cremophor EL free but also has the same mode of action as the paclitaxel suspended in DMSO on breast cancer cells MCF-7 and ovarian cancer cells OVCAR-3. The nanoemulsion formulation of paclitaxel (NFP) and paclitaxel suspended in DMSO (PSD) effectively inhibited the cell growth of human breast cancer cells MCF-7 (67%) and human ovarian cancer cells OVCAR-3 (72%) by MTS assay when treated with concentrations ranging from 1.2 μM-0.012 μM. The most important finding in this case was that NFP was 9-fold more potent than PSD at 12 nM in MCF-7 cells and 3-fold more potent in OVCAR-3 cells. In addition a 2-fold increase in caspase activation was observed when OVCAR-3 cells were treated with NFP and PSD in a time and dose dependent manner. To clarify the mechanism of action of NFP, the G2/M cell cycle arrest of MCF-7 and OVCAR-3 cells treated with NFP were studied by flow cytometry. A significant G2/M arrest in MCF-7 (67%) and OVCAR-3 (99%) was observed when the cells were treated with 1.2μM of NFP. Comparable cell cycle arrest results were obtained when MCF-7 and OVCAR-3 cells were treated with PSD while blank nanoemulsion control had no effect on G2/M cell cycle arrest and on cell proliferation.

In conclusion these studies successfully investigated the anti-cancer effects of crude garlic extract on a panel of human cancer cell lines via the mechanism of apoptosis and cell cycle arrest and thus demonstrate the potential of crude garlic extract as a pan cancer agent. Furthermore these research studies successfully demonstrated with our co-culture studies that CGE is also effective and inhibits the growth of tumors associated macrophages that are an important part of tumor microenvironment and in turn can play a critical role in slowing down cancer progression after further studies are carried out. These research studies also demonstrate that a SANE formulation of paclitaxel having a particle size of 20 nm can significantly inhibit cell proliferation, dramatically reduced zeta potential and increase apoptosis by 12-fold when compared to a nano blank, thus indicating the therapeutic potential for SANE as an anti-cancer drug delivery system. Further these results demonstrate that the effect of the SANE formulation of paclitaxel on the cell proliferation, apoptosis and cell cycle arrest of MCF-7 and OVCAR-3 cells are paclitaxel specific and is greater or as effective as paclitaxel suspended in DMSO (PSD) in vitro even after encapsulation into nanoemulsion, indicating its potential as an alternative drug delivery system for paclitaxel. (Abstract shortened by UMI.)