Aims To develop a novel nanomedicine approach for the treatment of multidrug-resistant (MDR) cancer by combining an anticancer drug and suppressors of cellular resistance within one multifunctional nanocarrier-based delivery system (NDS). Materials & methods The NDS consisted of cationic liposomes (carrier, 100–140 nm), doxorubicin (DOX, anticancer drug), siRNA targeted to MRP1 and BCL2 mRNA (suppressors of pump and nonpump cellular-resistance, respectively). The resulting approximately 500 nm complex has a zeta potential of +4 mV. Results & discussion The NDS provides an effective co-delivery of DOX and siRNA as well as cell-death induction and suppression of cellular resistance in MDR lung cancer cells. Conclusion We demonstrate NDS-enhanced efficiency of chemotherapy to a level that cannot be achieved by applying its components separately.

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...

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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.