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The complexity of cancer biology and its clinical manifestation are driven by genetic, epigenetic, transcriptomic, proteomic and metabolomic alterations, supported by genomic instability as well as by environmental conditions and lifestyle factors. Although novel therapeutic modalities are being introduced, efficacious cancer therapy is not achieved due to the frequent emergence of distinct mechanisms of multidrug resistance (MDR). Advanced technologies with the potential to identify and characterize cancer MDR could aid in selecting the most efficacious therapeutic regimens and prevent inappropriate treatments of cancer patients. Herein, we aim to present technological tools that will enhance our ability to surmount drug resistance in cancer in the upcoming decade. Some of these tools are already in practice such as next-generation sequencing. Identification of genes and different types of RNAs contributing to the MDR phenotype, as well as their molecular targets, are of paramount importance for the development of new therapeutic strategies aimed to enhance drug response in resistant tumors. Other techniques known for many decades are in the process of adaptation and improvement to study cancer cells’ characteristics and biological behavior including atomic force microscopy (AFM) and live-cell imaging. AFM can monitor in real-time single molecules or molecular complexes as well as structural alterations occurring in cancer cells induced upon treatment with various antitumor agents. Cell tracking methodologies and software tools recently progressed towards quantitative analysis of the spatio-temporal dynamics of heterogeneous cancer cell populations and enabled direct monitoring of cells and their descendants in 3D cultures. Besides, novel 3D systems with the advanced mimicking of the in vivo tumor microenvironment are applicable to study different cancer biology phenotypes, particularly drug-resistant and aggressive ones. They are also suitable for investigating new anticancer treatment modalities. The ultimate goal of using phenotype-driven 3D cultures for the investigation of patient biopsies as the most appropriate in vivo mimicking model, can be achieved in the near future.

Islet transplantation has the potential of reestablishing naturally-regulated insulin production in Type 1 diabetic patients. Nevertheless, this procedure is limited due to the low islet survival after transplantation and the lifelong immunosuppression to avoid rejection. Islet embedding within a biocompatible matrix provides mechanical protection and a physical barrier against the immune system thus, increasing islet survival. Alginate is the preferred biomaterial used for embedding insulin-producing cells because of its biocompatibility, low toxicity and ease of gelation. However, alginate gelation is poorly controlled, affecting its physicochemical properties as an injectable biomaterial. Including different concentrations of the phosphate salt Na2HPO4 in alginate hydrogels, we can modulate their gelation time, tuning their physicochemical properties like stiffness and porosity while maintaining an appropriate injectability. Moreover, these hydrogels showed good biocompatibility when embedding a rat insulinoma cell line, especially at low Na2HPO4 concentrations, indicating that these hydrogels have potential as injectable biomaterials for Type 1 Diabetes Mellitus treatment.

The main reasons for the inefficiency of standard glioblastoma (GBM) therapy are the occurrence of chemoresistance and the invasion of GBM cells into surrounding brain tissues. New therapeutic approaches obstructing these processes may provide substantial survival improvements. The purpose of this study was to assess the potential of lipophilic antioxidant coenzyme Q10 (CoQ10) as a scavenger of reactive oxygen species (ROS) to increase sensitivity to temozolomide (TMZ) and suppress glioma cell invasion. To that end, we used a previously established TMZ-resistant RC6 rat glioma cell line, characterized by increased production of ROS, altered antioxidative capacity, and high invasion potential. CoQ10 in combination with TMZ exerted a synergistic antiproliferative effect. These results were confirmed in a 3D model of microfluidic devices showing that the CoQ10 and TMZ combination is more cytotoxic to RC6 cells than TMZ monotherapy. In addition, cotreatment with TMZ increased expression of mitochondrial antioxidant enzymes in RC6 cells. The anti-invasive potential of the combined treatment was shown by gelatin degradation, Matrigel invasion, and 3D spheroid invasion assays as well as in animal models. Inhibition of MMP9 gene expression as well as decreased N-cadherin and vimentin protein expression implied that CoQ10 can suppress invasiveness and the epithelial to mesenchymal transition in RC6 cells. Therefore, our data provide evidences in favor of CoQ10 supplementation to standard GBM treatment due to its potential to inhibit GBM invasion through modulation of the antioxidant capacity.

The use of scaffolds composed of natural biodegradable matrices represents an attractive strategy to circumvent the lack of cell engraftment, a major limitation of stem cell therapy in cardiovascular diseases. Bovine-derived non-porous collagen scaffolds with different degrees of cross-linking (C0, C2, C5 and C10) were produced and tested for their mechanical behavior, in vitro biocompatibility with adipose-derived stem cells (ADSCs) and tissue adhesion and inflammatory reaction. Uniaxial tensile tests revealed an anisotropic behavior of collagen scaffolds (2×0.5cm) and statistically significant differences in the mechanical behavior between cross-linked and non-cross-linked scaffolds (n=5). In vitro, ADSCs adhered homogenously and showed a similar degree of proliferation on all four types of scaffolds (cells×10(3)cm(-2) at day 7: C0: 94.7±37.1; C2: 91.7±25.6; C5: 88.2±6.8; C10: 72.8±10.7; P=n.s.; n=3). In order to test the in vivo biocompatibility, a chronic myocardial infarction model was performed in rats and 1.2×1.2cm size collagen scaffolds implanted onto the heart 1month post-infarction. Six animals per group were killed 2, 7 and 30days after transplant. Complete and long-lasting adhesion to the heart was only observed with the non-cross-linked scaffolds with almost total degradation 1month post-transplantation. After 7 and 30days post-implantation, the degree of inflammation was significantly lower in the hearts treated with non-cross-linked scaffolds (day 7: C0: 10.2±2.1%; C2: 16.3±2.9%; C5: 15.9±4.8%; C10: 17.4±4.1%; P0.05 vs. C0; day 30: C0: 1.3±1.3%; C2: 9.4±3.0%; C5: 7.0±2.1%; C10: 9.8±2.5%; P0.01 vs. C0). In view of the results, the non-cross-linked scaffold (C0) was chosen as an ADSC-carrier sheet and tested in vivo. One week post-implantation, 25.3±7.0% of the cells transplanted were detected in those animals receiving the cell-carrier sheet whereas no cells were found in animals receiving cells alone (n=3 animals/group). We conclude that the biocompatibility and mechanical properties of the non-cross-linked collagen scaffolds make them a useful cell carrier that greatly favors tissue cell engraftment and may be exploited for cell transplantation in models of cardiac disease.

Chemoresistance and invasion properties are severe limitations to efficient glioma therapy. Therefore, development of glioma in vivo models that more accurately resemble the situation observed in patients emerges. Previously, we established RC6 rat glioma cell line resistant to DNA damaging agents including antiglioma approved therapies such as 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide (TMZ). Herein, we evaluated the invasiveness of RC6 cells in vitro and in a new orthotopic animal model. For comparison, we used C6 cells from which RC6 cells originated. Differences in cell growth properties were assessed by real-time cell analyzer. Cells’ invasive potential in vitro was studied in fluorescently labeled gelatin and by formation of multicellular spheroids in hydrogel. For animal studies, fluorescently labeled cells were inoculated into adult male Wistar rat brains. Consecutive coronal and sagittal brain sections were analyzed 10 and 25 days post-inoculation, while rats’ behavior was recorded during three days in the open field test starting from 25th day post-inoculation. We demonstrated that development of chemoresistance induced invasive phenotype of RC6 cells with significant behavioral impediments implying usefulness of orthotopic RC6 glioma allograft in preclinical studies for the examination of new approaches to counteract both chemoresistance and invasion of glioma cells.

We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC-19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC-19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it.

During the last years, a great effort has been invested into developing new TRAIL formulations with increased bioactivity, trying to overcome the resistance to conventional soluble TRAIL (sTRAIL) exhibited by many primary tumours. In our group, we have generated artificial lipid nanoparticles decorated with sTRAIL (LUV-TRAIL), emulating the physiological TRAIL-containing exosomes by which T-cells release TRAIL upon activation. We already demonstrated that LUV-TRAIL has greater cytotoxicity against both chemoresistant haematologic tumour cells and epithelial carcinoma cells compared to a form of sTRAIL similar to that used in clinical trials. In this study we have tested LUV-TRAIL in several human colon cancer cell lines with different sensitivity to sTRAIL. LUV-TRAIL significantly improved sTRAIL cytotoxicity in all colon cancer cell lines tested. Trying to ascertain the molecular mechanism by which LUV-TRAIL exhibited improved cytotoxicity, we demonstrated that TRAIL-coated lipid nanoparticles were able to activate DR5 more efficiently than sTRAIL, and this relied on LUV-TRAIL ability to promote DR5 clustering on the cell surface. Moreover, we show that TRAIL molecules are arranged in higher order oligomers only in LUV-TRAIL, which may explain their enhanced DR5 clustering ability. Finally, LUV-TRAIL showed significantly better antitumour activity than sTRAIL in an in vivo model using HCT-116 xenograft tumours in nude mice, validating its potential clinical application.

Background Despite being the stiffest airway of the bronchial tree, the trachea undergoes significant deformation due to intrathoracic pressure during breathing. The mechanical properties of the trachea affect the flow in the airway and may contribute to the biological function of the lung. Method A Fung-type strain energy density function was used to investigate the nonlinear mechanical behavior of tracheal cartilage. A bending test on pig tracheal cartilage was performed and a mathematical model for analyzing the deformation of tracheal cartilage was developed. The constants included in the strain energy density function were determined by fitting the experimental data. Result The experimental data show that tracheal cartilage is a nonlinear material displaying higher strength in compression than in tension. When the compression forces varied from −0.02 to −0.03 N and from −0.03 to −0.04 N, the deformation ratios were 11.03±2.18% and 7.27±1.59%, respectively. Both were much smaller than the deformation ratios (20.01±4.49%) under tension forces of 0.02 to 0.01 N. The Fung-type strain energy density function can capture this nonlinear behavior very well, whilst the linear stress–strain relation cannot. It underestimates the stability of trachea by exaggerating the displacement in compression. This study may improve our understanding of the nonlinear behavior of tracheal cartilage and it may be useful for the future study on tracheal collapse behavior under physiological and pathological conditions.

Cell microencapsulation represents a great promise for long-term drug delivery, but still several challenges need to be overcome before its translation into the clinic, such as the long term cell survival inside the capsules. On this regard, graphene oxide has shown to promote proliferation of different cell types either in two or three dimensions. Therefore, we planned to combine graphene oxide with the cell microencapsulation technology. We first studied the effect of this material on the stability of the capsules and next we analyzed the biocompatibility of this chemical compound with erythropoietin secreting C2C12 myoblasts within the microcapsule matrix. We produced 160 μm-diameter alginate microcapsules with increasing concentrations of graphene oxide and did not find modifications on the physicochemical parameters of traditional alginate microcapsules. Moreover, we observed that the viability of encapsulated cells within alginate microcapsules containing specific graphene oxide concentrations was enhanced. These results provide a relevant step for the future clinical application of graphene oxide on cell microencapsulation.

Background: Apo2-ligand/TRAIL, a member of the TNF cytokine superfamily capable of inducing apoptosis on tumor cells while sparing normal cells, is a promising anti-tumor agent. However, about 50% of human cancer are TRAIL resistant. Consequently, future TRAIL-based therapies will require the use of novel highly bioactive forms of TRAIL and/or the addition of sensitizing agents to TRAIL-induced apoptosis. Recently, we demonstrated that artificial lipid nanoparticles coated with bioactive TRAIL (LUV-TRAIL) greatly improved TRAIL activity and were able to induce apoptosis in chemoresistant hematological tumor cells. Objective: In this study, we have tested LUV-TRAIL-pro-apoptotic potential in human breast cancer. Method: Comparative analysis of cytotoxicity induced by sTRAIL and LUV-TRAIL was performed using several human breast tumor cell lines with different sensitivity to TRAIL. In vivo anti-tumor activity of LUV-TRAIL was also studied using a xeno-graft tumor model. Results: LUV-TRAIL improved not only sTRAIL in vitro cytotoxicity in all breast tumor cell lines tested but also showed more anti-tumor activity than sTRAIL in an in vivo xeno-graft tumor model. On the other hand, the concomitant treatment of LUV-TRAIL with the sensitizing agent flavopiridol (FVP) induced a higher level of cell death in TRAIL-resistant cell lines. TRAIL-sensitization induced by FVP was mediated by DR5 up-regulation, and interestingly TRAIL-apoptotic signaling was completely shifted towards DR5 upon FVP treatment. LUV-TRAIL could especially take advantage of this DR5 up-regulation, while sTRAIL was not able. Conclusion: To date, no special attention had been paid to this aspect of FVP-induced TRAIL-sensitization, may be because sTRAIL used were not able to take advantage of this DR5 up-regulation. Hence, LUV-TRAIL could be a better choice than sTRAIL to be used in combination with anti-tumor drugs inducing DR5 over-expression, since LUV-TRAIL is especially effective activating this death-receptor.

[EN] Polymer ceramic composites obtained as the result of a mineralization process hold great promise for the future of tissue engineering. Simulated body fluids (SBFs) are widely used for the mineralization of polymer scaffolds. In this work an exhaustive study with the aim of optimizing the mineralization process on a poly(L-lactic acid) (PLLA) macroporous scaffold has been performed. We observed that when an air plasma treatment is applied to the PLLA scaffold its hydroxyapatite nucleation ability is considerably improved. However, plasma treatment only allows apatite deposition on the surface of the scaffold but not in its interior. When a 5 wt % of synthetic hydroxyapatite (HAp) nanoparticles is mixed with PLLA a more abundant biomimetic hydroxyapatite layer grows inside the scaffold in SBF. The morphology, amount, and composition of the generated biomimetic hydroxyapatite layer on the pores surface have been analyzed. Large mineralization times are harmful to pure PLLA as it rapidly degrades and its elastic compression modulus significantly decreases. Degradation is retarded in the composite scaffolds because of the faster and extensive biomimetic apatite deposition and the role of HAp to control the pH. Mineralized scaffolds, covered by an apatite layer in SBF, were implanted in osteochondral lesions performed in the medial femoral condyle of healthy sheep. We observed that the presence of biomimetic hydroxyapatite on the pore s surface of the composite scaffold produces a better integration in the subchondral bone, in comparison to bare PLLA scaffolds., Contract grant sponsor: CIBER-BBN, VI National R&D&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, Instituto de Salud Carlos III with assistance from the European Regional Development Fund

The angiogenic properties of micron-sized (m-BG) and nano-sized (n-BG) bioactive glass (BG) filled poly(D,L lactide) (PDLLA) composites were investigated. On the basis of cell culture work investigating the secretion of vascular endothelial growth factor (VEGF) by human fibroblasts in contact with composite films (0, 5, 10, 20 wt %), porous 3D composite scaffolds, optimised with respect to the BG filler content capable of inducing angiogenic response, were produced. The in vivo vascularisation of the scaffolds was studied in a rat animal model and quantified using stereological analyses. The prepared scaffolds had high porosities (81 – 93 %), permeability (k = 5.4 – 8.6 × 10-9 m2) and compressive strength values (0.4 – 1.6 MPa) all in the range of trabecular bone. On composite films containing 20 wt % m-BG or n-BG, human fibroblasts produced 5 times higher VEGF than on pure PDLLA films. After 8 weeks of implantation, m-BG and n-BG containing scaffolds were well-infiltrated with newly formed tissue and demonstrated higher vascularisation and percentage blood vessel to tissue (11.6 – 15.1 %) than PDLLA scaffolds (8.5 %). This work thus shows potential for the regeneration of hard-soft tissue defects and increased bone formation arising from enhanced vascularisation of the construct.

The main goal of this study was to evaluate the potential of collagen meshes derived from porcine dermis as scaffolds for repairing pelvic organ prolapses. Mechanical properties of collagen meshes with different cross-linking percentages before and after Adipose Derived Stromal Cells (ADSC) seeding were studied as well as the cell-scaffold interaction. Uniaxial tensile tests of the collagen meshes with three different cross-linking percentages (full-, partial-, and noncross-linked) were carried out along orthogonal directions. Their mechanical properties were studied with the same tests before and after seeding with human derived adipose stem cells (ADSC) after 1 and 7 days. Histological analyses were performed to determine adhesion and proliferation of ADSC. Significant differences in mechanical properties of the unseeded meshes were observed between each orthogonal direction independently of the cross-linking percentage. A better cell adhesion rate was observed in the cross-linked meshes. An increase in the mechanical properties after cell seeding was observed with a direct relation with the degree of cross-linking. All meshes analyzed showed a marked anisotropy that should be taken into account during the surgical procedure. The cross-linking treatment increased cell adhesion and the mechanical properties of the collagen meshes after seeding. These results suggest that the mechanical properties of this type of collagen mesh could be useful as scaffolds for repair of pelvic organ prolapse.

Tracheal cartilage has been widely regarded as a linear elastic material either in experimental studies or in analytic and numerical models. However, it has been recently demonstrated that, like other fiber-oriented biological tissues, tracheal cartilage is a nonlinear material, which displays higher strength in compression than in extension. Considering the nonlinearity requires a more complex theoretical frame work and costs more to simulate. This study aims to quantify the deviation due to the simplified treatment of the tracheal cartilage as a linear material. It also evaluates the improved accuracy gained by considering the nonlinearity. Pig tracheal rings were used to exam the mechanical properties of cartilage and muscular membrane. By taking into account the asymmetric shape of tracheal cartilage, the collapse behavior of complete rings was simulated, and the compliance of airway and stress in the muscular membrane were discussed. The results obtained were compared with those assuming linear mechanical properties. The following results were found: (1) Models based on both types of material properties give a small difference in representing collapse behavior; (2) regarding compliance, the relative difference is big, ranging from 10 to 40% under negative pressure conditions; and (3) the difference in determining stress in the muscular membrane is small too

Samples of male and female mice skin were tested under monotonic and cyclic loading to mechanically characterize the tissue for large deformations. Cyclic tests have shown a typical Mullins effect widely known for elastomers and other soft tissues. No statistical difference was found in the maximum stretch of the sample after the fifth loading cycle for male ( 1.26 ± 0.035 ) and female ( 1.18 ± 0.083 ) . However, larger dispersion was obtained for the maximum stress for both genders, 0.61 ± 0.16 MPa for male and 0.78 ± 0.32 MPa for female. Results show the presence of inelastic strain and stress softening in the skin at large deformations. They also have shown how stress softening and residual strain change with the magnitude of the applied load. Good correlation was observed between the residual strain and the maximum strain previously attained by the sample during loading for all samples. However, the correlation was different between genders.

The mechanical property of the trachea affects the flow in the airway and may contribute to the biological function of the lung. Like many other biological tissues, the tracheal cartilage is likely to be a nonlinear material. To investigate the nonlinearity of tracheal cartilage, Fung-type strain energy density function was used. A mathematical model for analyzing the deformation of tracheal cartilage was developed and a bending test on pig trachea was performed. By fitting the experimental data, the constants included in the strain energy density function were therefore determined. The experimental data shows that tracheal cartilage displays higher strength in compression than in extension. Fung-type strain energy density function can capture this nonlinear behavior very well, whilst the linear stress-strain relation cannot. This study contributes to a better understanding of the material of tracheal cartilage and further benefits to its mechanical behavior under physiological and pathological conditions.