Liposomes as vehicles for targeted therapy of cancer. Part 2: clinical development

Lipopeptide Delivery of siRNA to the Central Nervous System

RNA interference is a relatively new tool used to silence specific genes in diverse biological systems. The development of this promising new technique for research and therapeutic use in studying and treating neurological diseases has been hampered by the lack of an efficient way to deliver siRNA transvascularly across the blood-brain barrier (BBB) to the central nervous system (CNS). Here we describe the generation of three different liposomal siRNA delivery vehicles to the CNS using the thin film hydration method. Utilizing cationic or anionic liposomes protects the siRNA from serum nucleases and proteases en route. To deliver the siRNA specifically to the CNS, the liposomes are complexed to a peptide that acts as a neuronal address by binding to nicotinic acetylcholine receptors (nAchRs). When injected intravenously, these liposome-siRNA-peptide complexes (LSPCs) or peptide addressed liposome encapsulated therapeutic siRNA (PALETS) resist serum degradation, effectively cross the BBB and deliver siRNA to AchR-expressing cells to suppress protein expression in the CNS.

Preparation and Antiproliferative Activity of Liposomes Containing a Combination of Cisplatin and Procainamide Hydrochloride

We have previously reported the enhancement of the antiproliferative and apoptotic activities of cis-diamminedichloroplatinum(II) (DDP) when it is coadministered with a class I antiarrhythmic drug procainamide hydrochloride (PA). Here, we determined the antiproliferative activity of DDP, either in solution or loaded in liposomes, in the presence of PA, in the bulk solution, or directly embedded in liposomes together with DDP. Our results show that PA potentiates the activity of DDP-liposomes and that this effect is maintained at least in some of the investigated cell types when both drugs were mixed and loaded together into liposomes.

Nuclear molecular imaging with nanoparticles: radiochemistry, applications and translation

Molecular imaging provides considerable insight into biological processes for greater understanding of health and disease. Numerous advances in medical physics, chemistry and biology have driven the growth of this field in the past two decades. With exquisite sensitivity, depth of detection and potential for theranostics, radioactive imaging approaches have played a major role in the emergence of molecular imaging. At the same time, developments in materials science, characterization and synthesis have led to explosive progress in the nanoparticle (NP) sciences. NPs are generally defined as particles with a diameter in the nanometre size range. Unique physical, chemical and biological properties arise at this scale, stimulating interest for applications as diverse as energy production and storage, chemical catalysis and electronics. In biomedicine, NPs have generated perhaps the greatest attention. These materials directly interface with life at the subcellular scale of nucleic acids, membranes and proteins. In this review, we will detail the advances made in combining radioactive imaging and NPs. First, we provide an overview of the NP platforms and their properties. This is followed by a look at methods for radiolabelling NPs with gamma-emitting radionuclides for use in single photon emission CT and planar scintigraphy. Next, utilization of positron-emitting radionuclides for positron emission tomography is considered. Finally, recent advances for multimodal nuclear imaging with NPs and efforts for clinical translation and ongoing trials are discussed.

Lipopeptide delivery of siRNA to the central nervous system

RNA interference is a relatively new tool used to silence specific genes in diverse biological systems. The development of this promising new technique for research and therapeutic use in studying and treating neurological diseases has been hampered by the lack of an efficient way to deliver siRNA transvascularly across the blood-brain barrier (BBB) to the central nervous system (CNS). Here we describe a method for delivering siRNA to the CNS by complexing it to a peptide that acts as a neuronal address by binding to acetylcholine receptors (AchRs). Adding cationic liposomes to the complex protects it from serum nucleases and proteases en route. When injected intravenously, these liposome-siRNA-peptide complexes resist serum degradation, effectively cross the BBB, and deliver siRNA to AchR-expressing cells to suppress protein expression in the CNS.

Nanotargeted radionuclides for cancer nuclear imaging and internal radiotherapy

Current progress in nanomedicine has exploited the possibility of designing tumor-targeted nanocarriers being able to deliver radionuclide payloads in a site or molecular selective manner to improve the efficacy and safety of cancer imaging and therapy. Radionuclides of auger electron-, α-, β-, and γ-radiation emitters have been surface-bioconjugated or after-loaded in nanoparticles to improve the efficacy and reduce the toxicity of cancer imaging and therapy in preclinical and clinical studies. This article provides a brief overview of current status of applications, advantages, problems, up-to-date research and development, and future prospects of nanotargeted radionuclides in cancer nuclear imaging and radiotherapy. Passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy are reviewed and summarized. Research on combing different modes of selective delivery of radionuclides through nanocarriers targeted delivery for tumor imaging and therapy offers the new possibility of large increases in cancer diagnostic efficacy and therapeutic index. However, further efforts and challenges in preclinical and clinical efficacy and toxicity studies are required to translate those advanced technologies to the clinical applications for cancer patients.