Synthesis approaches of amphiphilic copolymers for spherical micelle preparation: application in drug delivery.

The formation of polymeric micelles in aqueous environments through the self-assembly of amphiphilic polymers can provide a versatile platform to increase the solubility and permeability of hydrophobic drugs and pave the way for their administration. In comparison to various self-assembly-based vehicles, polymeric micelles commonly have a smaller size, spherical morphology, and simpler scale up process. The use of polymer-based micelles for the encapsulation and carrying of therapeutics to the site of action triggered a line of research on the synthesis of various amphiphilic polymers in the past few decades. The extended knowledge on polymers includes biocompatible smart amphiphilic copolymers for the formation of micelles, therapeutics loading and response to external stimuli, micelles with a tunable drug release pattern, etc. Different strategies such as ring-opening polymerization, atom transfer radical polymerization, reversible addition-fragmentation chain-transfer, nitroxide mediated polymerization, and a combination of these methods were employed to synthesize copolymers with diverse compositions and topologies with the proficiency of self-assembly into well-defined micellar structures. The current review provides a summary of the important polymerization techniques and recent achievements in the field of drug delivery using micellar systems. This review proposes new visions for the design and synthesis of innovative potent amphiphilic polymers in order to benefit from their application in drug delivery fields.

Evaluation of CAG repeat length in the androgen receptor gene and polycystic ovary syndrome risk in Iranian women: A case-control study.

Background: Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, which affects about 15-20% of women of reproductive age. The most important etiopathogenesis factor in its incidence is hyperandrogenism; over 70 candidate genes are known to be associated with this syndrome, such as the androgen receptor (AR) gene which encodes a steroid receptor and is located on the Xq11-12 chromosome. The N-terminus of exon 1 of AR contains a polymorphic trinucleotide repeat (CAG)n region that encodes glutamine tract. There are some studies showing that shorter AR CAG repeats are significantly related to enhanced AR sensitivity. Objective: This study investigated the frequency of the polymorphic expansion of the trinucleotide CAG repeats of AR in PCOS. Materials and Methods: 160 Iranian women aged 17-40 yr participated in this case-control study: 80 women as PCOS patients and 80 women as healthy controls according to the Rotterdam criteria. Other similar phenotype factors such as hyperandrogenism were not considered as PCOS. The frequency of polymorphic expansion of CAG trinucleotide repeats in PCOS patients was compared with the frequency in non-PCOS controls in using two primer sets for nested polymerase chain reaction. The polymerase chain reaction products were visualized on polyacrylamide gel and then were confirmed by a sequencing process. Results: The results did not show a significant correlation between the frequency of CAG repeats in AR and PCOS incidence. Conclusion: In contrast to some previous reports, the present data showed that the CAG length in PCOS cases did not significantly differ from that of controls. So, the AR (CAG)n does not appear to be a major factor for PCOS in Iranian women.

Self-assembled polymeric vesicles: Focus on polymersomes in cancer treatment.

The progress in advanced materials using nanoscale components can be conducted by an innovative idea involving combining nanotechnology approaches with supramolecular chemistry. This concept which is called self-assembly, is employed for formation of nanoscale self-assembled architectures with desirable properties. Self-assembly has emerged as a potent procedure for controlling the structure and characteristics of ensembles. Among self-assembled structures, polymersomes have revealed prodigious potential in drug delivery and development of smart nanomedicine due to their morphological similarities to cellular membranes and viral capsids. Moreover, their functional, tunable and stable membrane render them more advantageous to their lipid counter parts. Polymersomes have been used as different therapeutic carriers as drugs and imaging agents, as well as nanoreactors and artificial organelles. Here we review different basis of self-assembling polymersomes and their properties, the synthesis of various amphiphilic copolymers for vesicles preparation and potential applications of smart controlled release vesicles.

Na+/K+ ATPase-targeted delivery to metastatic breast cancer models.

In this study, we reported doxorubicin (DOX)-encapsulated nanoparticles (NPs) formulated with biocompatible and biodegradable poly (lactic-co-glycolic acid) (PLGA) and modified with a 13-amino acid peptide (S3) against sodium/potassium (Na+/K+)-ATPase pump alpha subunit to investigate its potential as antitumor agent. The morphological properties and size dispersity of the prepared nanoparticles were evaluated using scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation efficiency and in vitro release during 7 days were evaluated. Comparative in vitro cytotoxicity experiments demonstrated that the S3-conjugated nanoparticles (S3-PLGA-DOX NPs) had higher antiproliferative activity. Flow cytometry analysis confirmed the enhanced cellular uptake of S3-PLGA-DOX NPs in comparison with PLGA-DOX. In vivo study in 4T1 tumor-bearing BALB/C mice revealed that the S3-functionalized DOX-loaded NPs improved antitumor activity and survival rate of 4T1 tumor bearing mice. In this regard, conjugation of S3 peptide to the surface of DOX-loaded PLGA NPs provides site-specific delivery of DOX, inhibits 4T1 tumor growth in vivo and significantly decreases systemic toxicity. The obtained results suggested that the new (Na+/K+)-ATPase pump-targeted PLGA NPs as a target-selective delivery system for DOX has great potential for the treatment of breast cancer.

Peptide-based targeted therapeutics: Focus on cancer treatment.

Therapeutic peptides are attracting increasing attention for biomedical applications. Peptides present promising opportunities in targeted drug delivery due to their high specificity, selectivity, small dimensions, ease of modification, and high biocompatibility. During the last decade, the potential of peptides as therapeutics or targeting ligands has been boomed in nanotechnology and cancer research. This review summarizes various peptides as therapeutics and targeting ligands in cancer therapy. At first, two categories of tumor homing and cell penetrating peptides (CPPs) are introduced and then we will discuss the modification of CPPs. Then various types of tumor targeting peptides and their applications in cancer research are represented.

A novel VHH nanobody against the active site (the CA domain) of tumor-associated, carbonic anhydrase isoform IX and its usefulness for cancer diagnosis.

Expression of carbonic anhydrase IX (CAIX) significantly increases under hypoxic conditions in tumor cells. CAIX activity is executed by the catalytic domain (CA) located on the extracellular part of the enzyme. Neutralization of CAIX enzymatic activity reduces malignancy and survival of tumor cells. To inhibit the enzymatic activity, a VHH nanobody was developed against the CA domain of CAIX using phage display technology. Following immunization of a camel with the recombinant CAIX, VHH fragments were isolated by nested PCR on lymphocyte cDNA. Binding affinity of isolated nanobodies was tested by ELISA. A clone (K24) with the highest binding affinity was expressed in a soluble form. Affinity of K24 nanobody was determined to be approx. 2.3 × 10(-5). K24 nanobody recognized the expressed CAIX in the HeLa cell lines with high selectivity and specificity. These findings thus have usefulness for the diagnosis and treatment of cancers.