Polymeric micelles for MCL-1 gene silencing in breast tumors following systemic administration.

Aim: To develop delivery systems for efficient siRNA delivery to breast cancer.

Methods: Poly(ethylene oxide)-block-poly(ϵ-caprolactone-grafted-spermine) (PEO-b-P(CL-g-SP)) micelles were modified with cholesterol group in their core and with RGD4C peptide on their shell. Transfection efficiency of complexed MCL-1 siRNA in MDA-MB-435 was investigated, in vitro and in vivo following intratumoral and intravenous injection.

Effective down-regulation of signal transducer and activator of transcription 3 (STAT3) by polyplexes of siRNA and lipid-substituted polyethyleneimine for sensitization of breast tumor cells to conventional chemotherapy.

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that plays a major role in the development of resistance to conventional anti-cancer drugs in many types of cancer, when constitutively activated. Inhibition of STAT3 is considered as a promising strategy for inhibition of tumor growth and overcoming the drug resistance manifested. In this study, the capability of STAT3 knockdown by lipid substituted low molecular weight (2 kDa) polyethyleneimine (PEI2) complexes of STAT3-siRNA was assessed.

Engineering of amphiphilic block copolymers for polymeric micellar drug and gene delivery.

The use of nano-delivery systems formed through assembly of synthetic amphiphilic block copolymers (ABCs) in experimental medicine and pharmaceutical sciences is experiencing rapid development. This rapid development is driven by a crucial need in improving the performance of existing therapeutic agents, as well as the necessity for the development of advanced delivery systems for complex new entities such as genes, proteins and other cellular components. The flexibility in the construction of appropriate carriers for the delivery requirements of these complex new "drugs" offered by versatile polymer chemistry provides an undeniable advantage for polymer based nano-delivery systems compared to other colloids in this regard.

Optimization of the hydrophobic domain in poly(ethylene oxide)-poly(varepsilon-caprolactone) based nano-carriers for the solubilization and delivery of Amphotericin B.

The aim of the study was to develop a polymeric nano-carrier based on methoxy poly(ethylene oxide)-b-poly(epsilon-caprolactone) (MePEO-b-PCL) for the optimum solubilization and delivery of Amphotericin B (AmB). For this purpose, MePEO-b-PCL block co-polymers containing palmitoyl substituent on PCL (at a 100% substitution level) were synthesized through preparation of substituted monomer, that is, alpha-palmitoyl-epsilon-caprolactone, and further ring opening polymerization of this monomer by methoxy PEO (5000 g mol(-1)) using stannous octoate as catalyst. Prepared block co-polymers were characterized for their molecular weight by (1)H NMR and gel permeation chromatography, and assembled to polymeric nano-carriers.

Chemical modification of hydrophobic block in poly(ethylene oxide) poly(caprolactone) based nanocarriers: effect on the solubilization and hemolytic activity of amphotericin B.

The aim of this study was to develop methoxy poly(ethylene oxide)-b-poly(epsilon-caprolactone) (MePEO-b-PCL) containing stearyl (St) substituents on PCL, and assess the efficacy of nanocarriers formed from this structure in comparison to unmodified MePEO-b-PCL and those with carboxyl substitutes on PCL on the solubilization and delivery of Amphotericin B (AmB). Prepared block copolymers were characterized for their molecular weight by (1)H NMR and gel permeation chromatography. The self-assembly of synthesized MePEO-b-PStCL to spherical particles of nanometer size range was shown by dynamic light scattering as well as electron and atomic force microscopy.