Low penetration ability of Small Interfering RNA (siRNA) through the cellular plasma membrane combined with its limited stability in blood, limits the effectiveness of the systemic delivery of siRNA. In order to overcome such difficulties, we constructed a nanocarrier-based delivery system by taking advantage of the lessons learned from the problems in the delivery of DNA. In the present study, siRNA nanoparticles were first formulated with Poly(Propyleneimine) (PPI) dendrimers. To provide lateral and steric stability to withstand the aggressive environment in the blood stream, the formed siRNA nanoparticles were caged with a dithiol containing cross-linker molecules followed by coating them with Poly(Ethylene Glycol) (PEG) polymer. A synthetic analog of Luteinizing Hormone-Releasing Hormone (LHRH) peptide was conjugated to the distal end of PEG polymer to direct the siRNA nanoparticles specifically to the cancer cells. Our results demonstrated that this layer-by-layer modification and targeting approach confers the siRNA nanoparticles stability in plasma and intracellular bioavailability, provides for their specific uptake by tumor cells, accumulation of siRNA in the cytoplasm of cancer cells, and efficient gene silencing. In addition, in vivo body distribution data confirmed high specificity of the proposed targeting delivery approach which created the basis for the prevention of adverse side effects of the treatment on healthy organs.

To compare the influence of different characteristics of nanocarriers on the efficacy of chemotherapy and imaging, we designed, characterized, and evaluated three widely used nanocarriers: linear polymer, dendrimer and liposome in vitro and in vivo. These nanocarriers delivered the same anticancer drug (paclitaxel) and/or imaging agent (Cy5.5). A synthetic analog of LHRH peptide targeted to receptors overexpressed on the membrane of cancer cells was attached to the nanocarriers as a tumor targeting moiety. Significant differences were found between various studied non-targeted carriers in their cellular internalization, cytotoxicity, tumor and organ distribution and anticancer efficacy. LHRH peptide substantially enhanced intratumoral accumulation and anticancer efficacy of all delivery systems and minimized their adverse side effects. For the first time, the present study revealed that the targeting of nanocarriers to tumorspecific receptors minimizes the influence of the architecture, composition, size and molecular mass of nanocarriers on the efficacy of imaging and cancer treatment.

Development of cancer cell resistance, low accumulation of therapeutic drug in the lungs, and severe adverse treatment side effects represent main obstacles to efficient chemotherapy of lung cancer. To overcome these difficulties, we propose inhalation local delivery of anticancer drugs in combination with suppressors of pump and nonpump cellular resistance. To test this approach, nanoscale-based delivery systems containing doxorubicin as a cell death inducer, antisense oligonucleotides targeted to MRP1 mRNA as a suppressor of pump resistance and to BCL2 mRNA as a suppressor of nonpump resistance, were developed and examined on an orthotopic murine model of human lung carcinoma. The experimental results show high antitumor activity and low adverse side effects of proposed complex inhalatory treatment that cannot be achieved by individual components applied separately. The present work potentially contributes to the treatment of lung cancer by describing a unique combinatorial local inhalation delivery of drugs and suppressors of pump and nonpump cellular resistance.inhalation | antisense oligonucleotides | liposomes | orthotopic lung cancer model | pump and nonpump resistance L ung cancer is the leading cause of cancer-related death worldwide (1). Because of the size and distribution of lung cancer, cytoreductive surgery is not very effective for this disease, and therefore chemotherapy and/or radiation are the treatments of choice. However, despite the advances in cancer treatment and improvements in lifestyle and health care, death rates from lung cancer have not changed significantly over the last 50 years. In contrast, mortality from heart disease, the leading cause of death, declined almost 2.5-fold over the same period (2). The patient survival has been in a plateau for three decades (3), with a 5-year relative survival rate of less than 18% in most countries (4). The efficacy of chemotherapy in lung cancer is limited by the rapid development of cancer cell resistance during treatment. To overcome this resistance, higher doses of toxic anticancer drug(s) are administered, often producing adverse side effects in healthy organs. We hypothesize that a substantial enhancement in the efficiency of lung cancer treatment is possible by (i) local delivery of chemotherapeutic agent(s) by inhalation and (ii) simultaneous suppression of at least major mechanisms of lung cancer cell resistance. Local delivery of anticancer drugs directly into the lungs will increase their accumulation in tumor cells and will reduce adverse side effects on healthy organs by limiting drug concentration in the blood. Simultaneous suppression of cellular resistance in tumors will increase the intracellular concentration of the drug in cancer cells and enhance its cytolethality for cancerous cells.Patients with asthma and chronic obstructive pulmonary disease commonly use inhaled drugs (5). Although some chemotherapeutic agents can be delivered through the pulmonary or intratracheal route (6-9), most anticancer drugs cannot be inhaled in t...

The efficacy of chemotherapy of lung cancer is limited by the development of resistance in cancer cells during treatment. In most lung cancers, this resistance is associated with the overexpression of (a) multidrug resistance-associated protein (MRP) responsible for drug efflux from the cancer cells (pump resistance) and (b) BCL2 protein that activates antiapoptotic cellular defense (nonpump resistance). A novel liposomal proapoptotic anticancer drug delivery system was developed to enhance anticancer efficacy of the well-established drug doxorubicin (DOX). This multicomponent drug delivery system was tested on multidrug-sensitive and -resistant human small-cell lung cancer cells. The drug delivery system includes four components: (a) liposome as a carrier, (b) DOX as an inductor of apoptosis, (c) antisense oligonucleotides (ASOs) targeted to MRP1 mRNA as a suppressor of pump resistance, and (d) ASOs targeted to BCL2 mRNA as a suppressor of nonpump resistance. Intracellular internalization of ASOs and DOX; the influence of the proposed system on the expression of genes and proteins involved in the multidrug resistance, cytotoxicity, and apoptosis induction and antiapoptotic defense; and the activity of caspases were studied. It was found that the proposed liposomal delivery system successfully delivered ASOs and DOX to cell nuclei, inhibited MRP1 and BCL2 protein synthesis, and substantially increased the anticancer action of DOX by stimulating the caspase-dependent pathway of apoptosis in multidrug-resistant human lung cancer cells.

Purpose. To compare systemic intravenous and local intratracheal delivery of doxorubicin (DOX), antisense oligonucleotides (ASO) and small interfering RNA (siRNA). Methods. "Neutral" and cationic liposomes were used to deliver DOX, ASO, and siRNA. Liposomes were characterized by dynamic light scattering, zeta-potential, and atomic force microscopy. Cellular internalization of DOX, ASO and siRNA was studied by confocal microscopy on human lung carcinoma cells. In vivo experiments were carried out on nude mice with an orthotopic model of human lung cancer. Results. Liposomes provided for an efficient intracellular delivery of DOX, ASO, and siRNA in vitro. Intratracheal delivery of both types of liposomes in vivo led to higher peak concentrations and much longer retention of liposomes, DOX, ASO and siRNA in the lungs when compared with systemic administration. It was found that local intratracheal treatment of lung cancer with liposomal DOX was more efficient when compared with free and liposomal DOX delivered intravenously. Conclusions. The present study outlined the clear advantages of local intratracheal delivery of liposomal drugs for the treatment of lung cancer when compared with systemic administration of the same drug.

We designed, synthesized, and evaluated in vitro and in vivo a novel targeted anticancer polymeric prodrug containing multiple copies of tumor targeting moiety [synthetic luteinizing hormone-releasing hormone (LHRH) peptide, analog of LHRH] and anticancer drug (camptothecin). One, two, or three molecules of the targeting peptide and anticancer drug were covalently conjugated with bis(2-carboxyethyl) polyethylene glycol polymer using citric acid as a multivalent spacer. We showed that LHRH peptide was bound to extracellular receptors and localized in plasma membrane of cancer cells. The designed tumortargeted prodrug increased the solubility of anticancer drug and offered cytoplasmic and/or nuclear delivery of drug to cancer cells expressing LHRH receptors. The multicomponent prodrug containing three copies of the targeting peptide and drug was almost 100 times more cytotoxic and substantially had enhanced antitumor activity compared with the analogous nontargeted prodrug and prodrugs containing one or two copies of active components.Many anticancer drugs used in chemotherapy require modifications to increase solubility, decrease adverse side effects, limit nonspecific activity, increase circulation time, modify biodistribution, and so on. Various drug delivery systems (DDS) have been developed to provide these modifications

The efficacy of chemotherapy is substantially limited by the resistance of cancer cells to anticancer drugs that fluctuates significantly in different patients. Under identical chemotherapeutic protocols, some patients may receive relatively ineffective doses of anticancer agents while other individuals obtain excessive amounts of drugs that induce severe adverse side effects on healthy tissues. The current review is focused on an individualized selection of drugs and targets to suppress multidrug resistance. Such selection is based on the molecular characteristics of a tumor from an individual patient that can potentially improve the treatment outcome and bring us closer to an era of personalized medicine.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and often fatal form of interstitial lung disease. We hypothesized that the local pulmonary delivery of prostaglandin E2 (PGE2) by liposomes can be used for the effective treatment of IPF. To test this hypothesis, we used a murine model of bleomycin-induced IPF to evaluate liposomes which carries PGE2 topically to the lungs. Animal survival, body weight, hydroxyproline content in the lungs, lung histology, mRNA and protein expression were studied. After inhalation delivery, liposomes accumulated predominately in the lungs. In contrast, intravenous administration led to the accumulation of liposomes mainly in kidney, liver, and spleen. Liposomal PGE2 prevented the disturbances in the expression of many genes associated with the development of IPF, substantially restricted inflammation and fibrotic injury in the lung tissues, prevented decrease in body weight, limited hydroxyproline accumulation in the lungs and virtually eliminated mortality of animals after intratracheal instillation of bleomycin. In summary, our data provide evidence that pulmonary fibrosis can be effectively treated by the inhalation administration of liposomal form of PGE2 into the lungs. The results of the present investigations make the liposomal form of PGE2 an attractive drug for the effective inhalation treatment of idiopathic pulmonary fibrosis.