Nanotechnology based platforms for survivin targeted drug discovery

Introduction: Development of an effective, safe and targeted drug delivery system to fight cancer and other diseases is a prime focus in the area of drug discovery. The emerging field of nanotechnology has revolutionised the way cancer therapy and diagnosis is achieved primarily due to the recent advances in material engineering and drug availability. Further, the recognition of the crucial role played by anti-apoptotic proteins such as survivin, has initiated the development of therapeutics that can target this protein as an attempt to develop alternative cancer therapies. However, a key challenge faced in drug development is the efficient delivery of survivin-targeted molecules to specific areas in the body.Areas covered: This review primarily focuses on the different strategies employing nanotechnology for targeting survivin expressed in human cancers. Different nanomaterials incorporating nucleic molecules or drugs targeted at survivin are discussed and the results obtained from studies are highlighted.Expert opinion: There are extensive studies reporting different treatment regimens for cancer, however, they still result in systemic toxicity, reduced bioavailability and ineffective delivery. Novel approaches involve the use of biocompatible nanomaterials together with gene or drug molecules to target proteins such as survivin, which is overexpressed in cancerous cells. These nanoformulations allow the benefits of protecting easily degradable molecules, allow controlled release, and enhance targeted delivery and effectiveness. Hence, nanotherapy utilizing survivin targeting can be considered to play a key role in the development of personalized nanomedicine for cancer.

Novel alginate-enclosed chitosan–calcium phosphate-loaded iron-saturated bovine lactoferrin nanocarriers for oral delivery in colon cancer therapy

Aim: To develop polymeric-ceramic nanocarriers (NCs) in order to achieve oral delivery of the anticancer neutraceutical iron-saturated bovine lactoferrin (Fe-bLf) protein.

Materials & methods: Fe-bLf or paclitaxel (Taxol®) were adsorbed onto calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate. The Fe-bLf or Taxol-loaded NCs indicated as AEC–CP–Fe-bLf or AEC–CP–Taxol NCs, respectively, were made by combination of ionic gelation and nanoprecipitation. Size distribution, morphology, internalization and release profiles of the NCs were studied along with evaluation of in vitro and in vivo anticancer activities and compared with paclitaxel.

Results: AEC–CP–Fe-bLf NCs obtained spherical morphology and showed enhanced endocytosis, transcytosis and anticancer activity in Caco-2 cells in vitro. AEC–CP–Fe-bLf NCs were supplemented in an AIN 93G diet and fed to mice in both prevention and treatment human xenograft colon cancer models. AEC–CP–Fe-bLf NCs were found to be highly significantly effective when given orally, as a pretreatment, 1 week before Caco-2 cell injections. None of the mice from the AEC–CP–Fe-bLf NC-fed group developed tumors or showed any signs of toxicity, while the mice fed the control AIN 93G diet showed normal tumor growth. Fe-bLf or Taxol, when given orally in a diet as nanoformulations post-tumor development, showed a significant regression in the tumor size with complete inhibition of tumor growth later, while intratumoral injection of Taxol just delayed the growth of tumors. The pharmacokinetic and bioavailability studies indicated that nanoformulated Fe-bLf was predominantly present on tumor cells compared to non-nanoformulated Fe-bLf. Fe-bLf-loaded NCs were found to help in absorption of iron and thus may have utility in enhancing the iron uptake during iron deficiency without interfering with the absorption of calcium.

Conclusion: With the promising results of our study, the future potential of NC-loaded Fe-bLf in chemoprevention and in the treatment of human colon cancer, deserves further investigation for translational research and preclinical studies of other malignancies.

Synthesis and biological evaluation of novel folic acid receptor-targeted, β-cyclodextrin-based drug complexes for cancer treatment

Drug targeting is an active area of research and nano-scaled drug delivery systems hold tremendous potential for the treatment of neoplasms. In this study, a novel cyclodextrin (CD)-based nanoparticle drug delivery system has been assembled and characterized for the therapy of folate receptor-positive [FR(+)] cancer. Water-soluble folic acid (FA)-conjugated CD carriers (FACDs) were successfully synthesized and their structures were confirmed by 1D/2D nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and circular dichroism. Drug complexes of adamatane (Ada) and cytotoxic doxorubicin (Dox) with FACD were readily obtained by mixed solvent precipitation. The average size of FACD-Ada-Dox was 1.5-2.5 nm. The host-guest association constant Ka was 1,639 M-1 as determined by induced circular dichroism and the hydrophilicity of the FACDs was greatly enhanced compared to unmodified CD. Cellular uptake and FR binding competitive experiments demonstrated an efficient and preferentially targeted delivery of Dox into FR-positive tumor cells and a sustained drug release profile was seen in vitro. The delivery of Dox into FR(+) cancer cells via endocytosis was observed by confocal microscopy and drug uptake of the targeted nanoparticles was 8-fold greater than that of non-targeted drug complexes. Our docking results suggest that FA, FACD and FACD-Ada-Dox could bind human hedgehog interacting protein that contains a FR domain. Mouse cardiomyocytes as well as fibroblast treated with FACD-Ada-Dox had significantly lower levels of reactive oxygen species, with increased content of glutathione and glutathione peroxidase activity, indicating a reduced potential for Dox-induced cardiotoxicity. These results indicate that the targeted drug complex possesses high drug association and sustained drug release properties with good biocompatibility and physiological stability. The novel FA-conjugated β-CD based drug complex might be promising as an anti-tumor treatment for FR(+) cancer.

The Australian multiple sclerosis (MS) immunotherapy study: A prospective, multicentre study of drug utilisation using the MSBase platform

To prospectively characterise treatment persistence and predictors of treatment discontinuation in an Australian relapsing-remitting multiple sclerosis (RRMS) population. Tertiary MS treatment centres participating in the MSBase registry prospectively assessed treatment utilisation, persistence, predictors of treatment discontinuation and switch rates. Multivariable survival analyses were used to compare treatment persistence between drugs and to identify predictors of treatment discontinuation. 1113 RRMS patients were studied. Patients persisted on their first disease-modifying therapy (DMT) for a median of 2.5 years. Treatment persistence on GA was shorter than on all IFNβ products (p<0.03). Younger age at treatment initiation and higher EDSS were predictive of DMT discontinuation. Patients persisted on subsequent DMTs, for 2.3 years. Patients receiving natalizumab (NAT) as a subsequent DMT persisted longer on treatment than those on IFNβ or GA (p<0.000). The primary reason for treatment discontinuation for any drug class was poor tolerability. Annualised switch or cessation rates were 9.5–12.5% for individual IFNβ products, 11.6% for GA and 4.4% for NAT. This multicentre MS cohort study is the first to directly compare treatment persistence on IFNβ and GA to NAT. We report that treatment persistence in our Australian RRMS population is short, although patients receiving IFNβ as a first DMT persisted longer on treatment than those on GA. Additionally, patients receiving NAT as a subsequent DMT were more likely to persist on treatment than those switched to IFNβ or GA. EDSS and age at DMT initiation were predictive of DMT discontinuation. Treatment intolerance was the principal reason for treatment cessation.

Clinical aspects for survivin: a crucial molecule for targeting drug-resistant cancers

Drug resistance is frequently found in cancer patients who have prolonged chemotherapeutic treatments. Overcoming this phenomenon to make therapy available to these patients is one of the most important features in developing effective cancer therapeutic strategies. Identification of drug resistance causative molecules is one of the most focused areas of cancer research today. Many molecules have been identified in conferring cancer cells the property of drug resistance, and various small molecule inhibitors have been developed to target these molecules to restore the sensitivity of different traditional chemotherapeutic agents, which are frequently found to exhibit reduced potency during prolonged treatment, in cancer patients. Survivin, a member of the inhibitor of apoptosis proteins (IAP) family, has been identified as one of the most crucial biomarkers in the recognition of drug resistance. Survivin is overexpressed in tumor cells, helping in its proliferation and survival, and its overexpression is positively correlated with poor prognosis for cancer patients. Targeted therapeutic measures to inhibit survivin in cancers, particularly drug-resistant tumors, are the recent focus of research for cancer treatment.

Encapsulation of hydrophobic phthalocyanine with poly(N-isopropylacrylamide)/lipid composite microspheres for thermo-responsive release and photodynamic therapy

Phthalocyanine (Pc) is a type of promising sensitizer molecules for photodynamic therapy (PDT), but its hydrophobicity substantially prevents its applications. In this study, we efficiently encapsulate Pc into poly(N-isopropylacrylamide) (pNIPAM) microgel particles, without or with lipid decoration (i.e., Pc@pNIPAM or Pc@pNIPAM/lipid), to improve its water solubility and prevent aggregation in aqueous medium. The incorporation of lipid molecules significantly enhances the Pc loading efficiency of pNIPAM. These Pc@pNIPAM and Pc@pNIPAM/lipid composite microspheres show thermo-triggered release of Pc and/or lipid due to the phase transition of pNIPAM. Furthermore, in the in vitro experiments, these composite particles work as drug carriers for the hydrophobic Pc to be internalized into HeLa cells. After internalization, the particles show efficient fluorescent imaging and PDT effect. Our work demonstrates promising candidates in promoting the use of hydrophobic drugs including photosensitizers in tumor therapies. © 2014 by the authors.

Tailored hollow mesoporous silica nanoplatforms with biological labels for colon targeted drug deliver systems

Hollow mesoporous silica nanoparticles (HMSNs) were synthesized via a new strategy. HMSNs have a high drug loading, controlled release behaviour, and specifically targeting when bioconjugated with Epidermal Growth Factor. The promising in vitro cell tests have revealed the great potential of the HMSNs to be used for cancer therapy.

Molecular insights and oligonucleotide based targeted gene therapy against cancer

The thesis helps to unravel the function of T lymphoma invasion and metastasis protein (TIAM1) and nucleolin, a nucleolar protein in retinoblastoma tumorigenesis. Aptamer based targeted imaging; drug and gene delivery to retinoblastoma and epithelial cancer cells was attained. The work work finally opened up avenues for cancer stem cell targeting using aptamers, imaging of cancer cells using novel bio-orthogonal agent and use of aptamer for blocking the miRNA-17-92 cluster maturation.

Locked nucleic acid modified bi-specific aptamer-targeted nanoparticles carrying survivin antagonist towards effective colon cancer therapy

We investigated the anti-cancer activity of alginate coated chitosan nanoparticles (CHNP) encapsulating cell-permeable dominant negative survivin (SR9) with locked nucleic acid (LNA) aptamers targeting EpCAM and nucleolin (termed as "nanobullets") in vitro (2D and 3D cell culture models) and in vivo (colon cancer mouse xenograft model). We incorporated three LNA modifications in each sequence in order to enhance the stability of these aptamers. Confocal microscopy revealed binding of the LNA-aptamers to their specific markers with high affinity. The muco-adhesive nanobullets showed 6-fold higher internalization in cancer cells when compared to non-cancerous cells, suggesting a tumour specific uptake. A higher intensity of nanobullets was observed in both the periphery and the core of the multicellular tumour spheroids compared to non-targeted CHNP-SR9. The nanobullets were found to be the highly effective as they led to a 2.26 fold (p < 0.05) reduction at 24 h and a 4.95 fold reduction (p ≤ 0.001) in the spheroid size at 72 h. The tumour regression was 4 fold higher in mice fed on a nanobullet diet when compared to a control diet. The nanobullets were able to show a significantly high apoptotic (p ≤ 0.0005) and necrotic index in the tumour cell population (p ≤ 0.005) when compared to void NPs. Therefore, our nanoparticles have shown highly promising results and therefore deliver a new conduit towards the approach of cancer-targeted nanodelivery. This journal is

Molecular regulation of survivin targeted nano-therapy in advanced prostate cancer

 The increasing complexities of prostate cancer disease progression necessitates more stable and less toxic therapeutic strategies. The current study demonstrated for the first time, the survivin targeted anti-cancer therapeutic activity of the bio-molecular drugs such as SurR9-C84A and bovine lactoferrin in inducing prostate cancer specific apoptosis. Moreover, improved therapeutic efficacy was conferred to these bio-molecules either by their encapsulation in stem cell targeted bio-compatible nanoparticles, or by the synthesis of protein-cytotoxic drug conjugates. This study also highlighted the role played by miRNAs in the regulation of iron metabolism and apoptosis, mediated by the selective activation of p53 and PTEN pathways.

Can cancer therapy be achieved by bridging apoptosis and autophagy: A method based on microRNA-dependent gene therapy and phytochemical targets

A failure of a cell to self destruct has long been associated with cancer progression and development. The fact that tumour cells may not instigate cell arrest or activate cell death mechanisms upon cancer drug delivery is a major concern. Autophagy is a mechanism whereby cell material can be engulfed and digested while apoptosis is a self-killing mechanism, both capable of hindering multiplication after cell injury. In particular situations, autophagy and apoptosis seem to co-exist simultaneously or interdependently with the aid of mutual proteins. This review covers roles of microRNAs and chemopreventive agents and makes an attempt at outlining possible partnerships in maximizing cancer cell death with minimal normal cell damage.

The Glutathione System: a new drug target in neuroimmune disorders

Glutathione (GSH) has a crucial role in cellular signaling and antioxidant defenses either by reacting directly with reactive oxygen or nitrogen species or by acting as an essential cofactor for GSH S-transferases and glutathione peroxidases. GSH acting in concert with its dependent enzymes, known as the glutathione system, is responsible for the detoxification of reactive oxygen and nitrogen species (ROS/RNS) and electrophiles produced by xenobiotics. Adequate levels of GSH are essential for the optimal functioning of the immune system in general and T cell activation and differentiation in particular. GSH is a ubiquitous regulator of the cell cycle per se. GSH also has crucial functions in the brain as an antioxidant, neuromodulator, neurotransmitter, and enabler of neuron survival. Depletion of GSH leads to exacerbation of damage by oxidative and nitrosative stress; hypernitrosylation; increased levels of proinflammatory mediators and inflammatory potential; dysfunctions of intracellular signaling networks, e.g., p53, nuclear factor-κB, and Janus kinases; decreased cell proliferation and DNA synthesis; inactivation of complex I of the electron transport chain; activation of cytochrome c and the apoptotic machinery; blockade of the methionine cycle; and compromised epigenetic regulation of gene expression. As such, GSH depletion has marked consequences for the homeostatic control of the immune system, oxidative and nitrosative stress (O&NS) pathways, regulation of energy production, and mitochondrial survival as well. GSH depletion and concomitant increase in O&NS and mitochondrial dysfunctions play a role in the pathophysiology of diverse neuroimmune disorders, including depression, myalgic encephalomyelitis/chronic fatigue syndrome and Parkinson’s disease, suggesting that depleted GSH is an integral part of these diseases. Therapeutical interventions that aim to increase GSH concentrations in vivo include N-acetyl cysteine; Nrf-2 activation via hyperbaric oxygen therapy; dimethyl fumarate; phytochemicals, including curcumin, resveratrol, and cinnamon; and folate supplementation.