Browsing by Subject "neuroblastoma"
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Item Optimization of Reconstituted High Density Lipoprotein nanoparticles as a Delivery System for Neuroblastoma(2013-12-01) Hinze, Cheryl L.; Lacko, Andras G.Despite many advances in cancer therapy over the last few decades, cancer remains one of the most common causes of death in not only the United States, but around the world. Two of the major problems cancer patients face today are the horrific side effects associated with chemotherapy, and the development of drug resistance. Both of these become even bigger problems when they are applied to children. Neuroblastoma is one of the most common forms of pediatric cancer. High risk Neuroblastoma patients are commonly faced with intensive multi-modal therapies in attempt to overcome a very aggressive disease. Due to the intensive therapy required, side effects can often linger even after remission is achieved in these patients, and multi-drug resistance is common due to the high levels of Doxorubicin administered. New solutions are needed in order to overcome both of these problems in Neuroblastoma as well as other types of cancer. In this thesis, we studied the effects of different formulation and preparation techniques for the reconstituted high density lipoprotein nanoparticle model for anti-cancer agent delivery. During these studies we found that naturally derived mixes of phosphatidylcholine, and lower levels of apolipoprotein A-1 increase the encapsulation efficiency of the rHDL nanoparticles. We also determined that the addition of lyophilization during preparation before cholate dialysis, forms a more homogeneous preparation. After the optimization of the particle formulation and preparation, we tested the efficacy of two model anti-cancer agents in different cancer cells. First we showed the ability of the rHDL-siRNA nanoparticles to knockdown the SR-B1 protein is greater than the knockdown of a commercial transfection kit. Finally we prove that the rHDL also improves the cytotoxic efficacy of a novel treatment for Neuroblastoma involving Imatinib Mesylate and Saquinavir. In conclusion, the results of this thesis show a more detailed knowledge of the rHDL nanoparticle formulation as well as how it can be applied as an effective delivery system for both siRNA and chemotherapeutic agents. This data should help push our formulations closer to clinical applications, and toward helping reduce the toxic side effects of many chemotherapeutic agents, as well as reducing the incidence of drug resistance.Item TARGETED DELIVERY OF A NOVEL COMBINATION THERAPY FOR NEUROBLASTOMA(2013-04-12) Hinze, CherylPurpose: Neuroblastoma (NB) is the most common solid extra-cranial tumor found in children. The prognosis for late stage or high risk Neuroblastoma patients remains very low despite very intense multi-modal therapies. The patients that do survive, and reach remission from aggressive NB have a much increased risk of developing cancer again later in life. Therefore it is important to increase the efficacy of the current treatments, while decreasing their toxic side effects in order to raise these patients' standard of living. One of the novel therapies currently being explored for NB is a combination of the chemotherapeutic agent Imatinib Mesylate (Imatinib), a tyrosine kinase inhibitor specific for c-kit and platelet derived growth factor receptor, both of which are expressed on NB cells, and Saquinavir, a protease inhibitor with anti-cancer properties, that is currently used in anti-HIV therapy. Previous studies have shown Saquinavir to be effective against Chronic Myeloid Leukemia cells; therefore we anticipate that it might also be effective against NB cells and tumors. We propose that the encapsulation of this combination of drugs into our reconstituted high density lipoprotein (rHDL) system will not only improve their therapeutic action against NB, but will also reduce their off target toxicity, via amount of toxic side effects due to the selective delivery properties of the rHDL Nanoparticles. Methods: The rHDL particles were prepared using the cholate dialysis method. The particles were then characterized for their physical properties and chemical composition. Size of the particles was determined using dynamic light scattering. SJ-N-KP and SMS-KCNR cells were plated in 96 well plates at a concentration of 5 x 103 cells per well. The Dojindo CCK8 test was used to measure cytotoxicity for both free and encapsulated Imatinib and Saquinavir after 48 hour exposure to the drugs. Results: The mean diameter of the Imatinib-rHDL particles was found to be 97.1 nm, and the mean diameter of the Saquinavir-rHDL particles was found to be 33.1 nm. Encapsulation of the Saquinavir into rHDL nanoparticles has shown up to a 100 fold increase in cytotoxicity in NB cell lines. Conclusions: Our studies show that encapsulation of this novel drug combination into rHDL nanoparticles greatly increases their efficacy against NB cell lines, thus indicating the potential of this system in combination to improve therapy, and raise the prognosis of NB patients.Item Targeted Nanoparticles for the Treatment of Neuroblastoma(2011-05-01) Pratap, Suraj; Lacko, Andras G.Neuroblastoma (NB) is one of the most frequently diagnosed tumors in infants and children. However, the mechanism by which it is initiated and subsequently develops on the molecular and cellular level is yet to be fully elucidated. Its wide spectrum of clinical presentation has baffled physicians and biomedical scientists alike. The variant called high risk neuroblastoma (HRNB) is extremely resistant to the currently available drug regimes. Despite the recent advances in anti-cancer agents and the use of multi-modality therapy for the treatment of HRNB the morbidity and mortality in this group of patients continues to remain high. The purpose of our project was to find novel alternative therapeutic approaches by encapsulating known anti-NB agents in a lipoprotein based formulation to achieve selected, targeted delivery of these drugs to HRNB tumors. We wanted to enhance the therapeutic efficacy of these drugs that have shown encouraging results in pre-clinical trials but have so far exhibited an adverse pharmacokinetic profile precluding their systemic application. Our laboratory has been working for the last several years on a novel drug delivery platform by encapsulating drugs into the core of high density lipoprotein (HDL) type nano-particles. Using this strategy, we encapsulated all-trans retinoic acid (ATRA), fenretinide (FR) and valrubicin into reconstituted HDL (rHDL) nanoparticles and subsequently evaluated some of their physical and chemical properties and their anti-NB potential. Further, we tested the efficiency of an apolipoprotein mimetic peptide called 5-A peptide as a component of rHDL particles and compared its efficiency with apolipoprotein A-1 (Apo-A1). The 5-A peptide offers numerous advantages over the Apo-A-1 both in terms of cost of production as well as manufacturing time. After successfully encapsulating the drugs, we characterized them and tested their cytotoxic potential on various cancerous cell lines. We also conducted cell uptake studies to test our hypothesis of tissue targeting and selective uptake of rHDL nano-particles mediated by the scavenger receptor type B1 (SR-B1). We conducted a pilot study on nude mice in which we administered rHDL containing fluorescent dye intravenously in mice xenografted with NB tumors and took subsequent images to track its distribution in the body. Our results demonstrate that it is possible to encapsulate ATRA, FR and valrubicin into rHDL preparations with a predictable efficiency; these nano-particles show a dose dependent cytotoxic effect on NB cell lines. We anticipate that the results of our studies will facilitate the application of liposomal nano-particles and these novel drugs in the treatment of HRNB in the future.