Targeted magnetic nanoparticle hyperthermia for the treatment of oral cancer.

INTRODUCTION: Patients with oral squamous cell carcinoma currently experience a five-year survival rate of approximately 60% with conventional surgical, chemotherapy and radiotherapy treatments. Magnetic hyperthermia offers an alternative treatment method by utilising the heating properties of magnetic nanoparticles to produce thermal ablation of the tumour site when exposed to an alternating magnetic field. In this study, we investigate in vitro if targeted magnetic hyperthermia offers a potential treatment for oral squamous cell carcinoma. MATERIALS AND METHODS: Magnetic iron oxide nanoparticles, with a biocompatible silica coating, were produced and conjugated with antibodies to target integrin αvß6, a well-characterised oral squamous cell carcinoma biomarker. Utilising the heating properties of the magnetic nanoparticles, we exposed them to an alternating magnetic field to produce thermo ablation of tumour cells either negative for or overexpressing integrin αvß6. RESULTS: The cell surface biomarker, αvß6 integrin, was upregulated in tissue biopsies from oral squamous cell carcinoma patients compared to normal tissue. Functionalisation of the silica coating with anti-αvß6 antibodies enabled direct targeting of the nanoparticles to αvß6 overexpressing cells and applying thermal therapy significantly increased killing of the targeted tumour cells compared to control cells. CONCLUSION: Combining antibody-targeting magnetic nanoparticles with thermal ablation offers a promising therapy for the targeted treatment of oral squamous cell carcinoma.

Characterisation of a functional rat hepatocyte spheroid model.

Many in vitro liver cell models, such as 2D systems, that are used to assess the hepatotoxic potential of xenobiotics suffer major limitations arising from a lack of preservation of physiological phenotype and metabolic competence. To circumvent some of these limitations there has been increased focus on producing more representative 3D models. Here we have used a novel approach to construct a size-controllable 3D hepatic spheroid model using freshly isolated primary rat hepatocytes (PRH) utilising the liquid-overlay technique whereby PRH spontaneously self-assemble in to 3D microtissues. This system produces viable spheroids with a compact in vivo-like structure for up to 21 days with sustained albumin production for the duration of the culture period. F-actin was seen throughout the spheroid body and P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (MRP2) transporters had polarised expression on the canalicular membrane of hepatocytes within the spheroids upon formation (day 3). The MRP2 transporter was able to functionally transport 5 µM 5-chloromethylfluorescein diacetate (CMFDA) substrates into these canalicular structures. These PRH spheroids display in vivo characteristics including direct cell-cell contacts, cellular polarisation, 3D cellular morphology, and formation of functional secondary structures throughout the spheroid. Such a well-characterised system could be readily exploited for pre-clinical and non-clinical repeat-dose investigations and could make a significant contribution to replace, reduce and refine the use of animals for applied research.

A simple rocker-induced mechanical stimulus upregulates mineralization by human osteoprogenitor cells in fibrous scaffolds.

Biodegradable electrospun polycaprolactone scaffolds can be used to support bone-forming cells and could fill a thin bony defect, such as in cleft palate. Oscillatory fluid flow has been shown to stimulate bone production in human progenitor cells in monolayer culture. The aim of this study was to examine whether bone matrix production by primary human mesenchymal stem cells from bone marrow or jaw periosteal tissue could be stimulated using oscillatory fluid flow supplied by a standard see-saw rocker. This was investigated for cells in two-dimensional culture and within electrospun polycaprolactone scaffolds. From day 4 of culture onwards, samples were rocked at 45 cycles/min for 1 h/day, 5 days/week (rocking group). Cell viability, calcium deposition, collagen production, alkaline phosphatase activity and vascular endothelial growth factor secretion were evaluated to assess the ability of the cells to undergo bone differentiation and induce vascularisation. Both cell types produced more mineralized tissue when subjected to rocking and supplemented with dexamethasone. Mesenchymal progenitors and primary human mesenchymal stem cells from bone marrow in three-dimensional scaffolds upregulated mineral deposition after rocking culture as assessed by micro-computed tomography and alizarin red staining. Interestingly, vascular endothelial growth factor secretion, which has previously been shown to be mechanically sensitive, was not altered by rocking in this system and was inhibited by dexamethasone. Rocker culture may be a cost effective, simple pretreatment for bone tissue engineering for small defects such as cleft palate.