23 research outputs found
Al2O3 microresonators for passive and active sensing applications
The Al2O3 waveguide technology was explored for sensing applications. Passive microring resonators with a quality factor in air of 3.2×105 were developed with a bulk refractive index sensitivity of ~100 nm/RIU and limit of detection of ~10-6 RIU. These were functionalized to detect the biomarker rhS100A4 from urine down to concentrations of 3 nM. Furthermore, Al2O3:Yb3+ microdisk lasers were realized that exhibited single mode lasing operation in water. Their lasing wavelength was tuned by varying the bulk refractive index and a bulk refractive index sensitivity of ~20 nm/RIU with a LOD of ~3×10-6 was achieved
In vivo anticancer evaluation of the hyperthermic efficacy of anti-human epidermal growth factor receptor-targeted PEG-based nanocarrier containing magnetic nanoparticles
Polymeric nanoparticles with targeting moieties containing magnetic nanoparticles as theranostic agents have considerable potential for the treatment of cancer. Here we report the chemical synthesis and characterization of a poly(D,L-lactide-co-glycolide)-b-poly(ethylene glycol)-based nanocarrier containing iron oxide nanoparticles and human epithelial growth factor receptor on the outer shell. The nanocarrier was also radiolabeled with (99m)Tc and tested as a theranostic nanomedicine, ie, it was investigated for both its diagnostic ability in vivo and its therapeutic hyperthermic effects in a standard A431 human tumor cell line. Following radiolabeling with (99m)Tc, the biodistribution and therapeutic hyperthermic effects of the nanosystem were studied noninvasively in vivo in tumor-bearing mice. A substantial decrease in tumor size correlated with an increase in both nanoparticle concentration and local temperature was achieved, confirming the possibility of using this multifunctional nanosystem as a therapeutic tool for epidermoid carcinoma
Therapeutic targeting of tumor growth and angiogenesis with a novel anti-S100A4 monoclonal antibody
S100A4, a member of the S100 calcium-binding protein family secreted by tumor and stromal cells, supports tumorigenesis by stimulating angiogenesis. We demonstrated that S100A4 synergizes with vascular endothelial growth factor (VEGF), via the RAGE receptor, in promoting endothelial cell migration by increasing KDR expression and MMP-9 activity. In vivo overexpression of S100A4 led to a significant increase in tumor growth and vascularization in a human melanoma xenograft M21 model. Conversely, when silencing S100A4 by shRNA technology, a dramatic decrease in tumor development of the pancreatic MiaPACA-2 cell line was observed. Based on these results we developed 5C3, a neutralizing monoclonal antibody against S100A4. This antibody abolished endothelial cell migration, tumor growth and angiogenesis in immunodeficient mouse xenograft models of MiaPACA-2 and M21-S100A4 cells. It is concluded that extracellular S100A4 inhibition is an attractive approach for the treatment of human cancer
Overexpression of S100A4 in human cancer cell lines resistant to methotrexate
Methotrexate is a chemotherapeutic drug that is used in therapy of a wide variety of cancers. The
efficiency of treatment with this drug is compromised by the appearance of resistance. Combination treatments of
MTX with other drugs that could modulate the expression of genes involved in MTX resistance would be an adequate
strategy to prevent the development of this resistance.
Methods: The differential expression pattern between sensitive and MTX-resistant cells was determined by whole
human genome microarrays and analyzed with the GeneSpring GX software package. A global comparison of all the
studied cell lines was performed in order to find out differentially expressed genes in the majority of the MTX-resistant
cells. S100A4 mRNA and protein levels were determined by RT-Real-Time PCR and Western blot, respectively.
Functional validations of S100A4 were performed either by transfection of an expression vector for S100A4 or a siRNA
against S100A4. Transfection of an expression vector encoding for β-catenin was used to inquire for the possible
transcriptional regulation of S100A4 through the Wnt pathway.
Results: S100A4 is overexpressed in five out of the seven MTX-resistant cell lines studied. Ectopic overexpression of this
gene in HT29 sensitive cells augmented both the intracellular and extracellular S100A4 protein levels and caused
desensitization toward MTX. siRNA against S100A4 decreased the levels of this protein and caused a
chemosensitization in combined treatments with MTX. β-catenin overexpression experiments support a possible
involvement of the Wnt signaling pathway in S100A4 transcriptional regulation in HT29 cells.
Conclusions: S100A4 is overexpressed in many MTX-resistant cells. S100A4 overexpression decreases the sensitivity of
HT29 colon cancer human cells to MTX, whereas its knockdown causes chemosensitization toward MTX. Both
approaches highlight a role for S100A4 in MTX resistanc
Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort
Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2, 445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD
Tackling Lipophilicity of Peptide Drugs: Replacement of the Backbone <i>N</i>‑Methyl Group of Cilengitide by <i>N</i>‑Oligoethylene Glycol (<i>N</i>‑OEG) Chains
Cilengitide is an RGD-peptide of
sequence cyclo[RGDf<i>N</i>MeV] that was was developed as
a highly active and selective ligand
for the α<sub>v</sub>β<sub>3</sub> and α<sub>v</sub>β<sub>5</sub> integrin receptors. We describe the synthesis
of three analogues of this peptide in which the <i>N</i>-Me group has been replaced by <i>N</i>-oligoethylene glycol
(<i>N</i>-OEG) chains of increasing size: namely <i>N</i>-OEG<sub>2</sub>, <i>N</i>-OEG<sub>11</sub>,
and <i>N</i>-OEG<sub>23</sub>, which are respectively composed
of 2, 11, and 23 ethylene oxide monomer units. The different <i>N</i>-OEG cyclopeptides and the original peptide were compared
with respect to lipophilicity and biological activity. The <i>N</i>-OEG<sub>2</sub> analogue was straightforward to synthesize
in solid phase using an Fmoc-<i>N</i>-OEG<sub>2</sub> building
block. The syntheses of the <i>N</i>-OEG<sub>11</sub> and <i>N</i>-OEG<sub>23</sub> cyclopeptides are hampered by the increased
steric hindrance of the <i>N</i>-substituent, and could
only be achieved by segment coupling, which takes place with epimerization
and thus requires extensive product purification. All the <i>N</i>-OEG analogues were found to be more hydrophobic than the
parent peptide, and their hydrophobicity was systematically enhanced
upon increasing the length of the OEG chain. The <i>N</i>-OEG<sub>2</sub> cyclopeptide displayed the same capacity as Cilengitide
to inhibit the integrin-mediated adhesion of HUVEC endothelial, DAOY
gliobastoma, and HT-29 colon cancer cells to their ligands vitronectin
and fibrinogen. The <i>N</i>-OEG<sub>11</sub> and <i>N</i>-OEG<sub>23</sub> analogues also inhibited cell adhesion
to these immobilized ligands, but their IC<sub>50</sub> values dropped
by 1 order of magnitude with respect to the parent peptide. These
results indicate that replacement of the backbone <i>N</i>-Me group of Cilengitide by a short <i>N</i>-OEG chain
provides a more lipophilic analogue with a similar biological activity.
Upon increasing the size of the <i>N</i>-OEG chain, liophilicity
is enhanced, but synthetic yields drop and the longer polymer chains
may impede targeted binding
Overexpression of S100A4 in human cancer cell lines resistant to methotrexate
Abstract Background Methotrexate is a chemotherapeutic drug that is used in therapy of a wide variety of cancers. The efficiency of treatment with this drug is compromised by the appearance of resistance. Combination treatments of MTX with other drugs that could modulate the expression of genes involved in MTX resistance would be an adequate strategy to prevent the development of this resistance. Methods The differential expression pattern between sensitive and MTX-resistant cells was determined by whole human genome microarrays and analyzed with the GeneSpring GX software package. A global comparison of all the studied cell lines was performed in order to find out differentially expressed genes in the majority of the MTX-resistant cells. S100A4 mRNA and protein levels were determined by RT-Real-Time PCR and Western blot, respectively. Functional validations of S100A4 were performed either by transfection of an expression vector for S100A4 or a siRNA against S100A4. Transfection of an expression vector encoding for β-catenin was used to inquire for the possible transcriptional regulation of S100A4 through the Wnt pathway. Results S100A4 is overexpressed in five out of the seven MTX-resistant cell lines studied. Ectopic overexpression of this gene in HT29 sensitive cells augmented both the intracellular and extracellular S100A4 protein levels and caused desensitization toward MTX. siRNA against S100A4 decreased the levels of this protein and caused a chemosensitization in combined treatments with MTX. β-catenin overexpression experiments support a possible involvement of the Wnt signaling pathway in S100A4 transcriptional regulation in HT29 cells. Conclusions S100A4 is overexpressed in many MTX-resistant cells. S100A4 overexpression decreases the sensitivity of HT29 colon cancer human cells to MTX, whereas its knockdown causes chemosensitization toward MTX. Both approaches highlight a role for S100A4 in MTX resistance.</p
Al2O3 Microresonator Based Passive and Active Biosensors
Al2O3 microresonators were realized for sensing applications of both passive and active devices. Passive microring resonators exhibited quality factors up to 3.2×105 in air. A bulk refractive index sensitivity of 100 nm/RIU was demonstrated together with a limit of detection of 10-6 RIU. Functionalizing their surface allowed for the label-free detection of the biomarker rhS100A4 from urine with a limit of detection of 3 nM. Furthermore, single-mode Al2O3:Yb3+ microdisk lasers were realized that could operate in an aqueous environment. Upon varying the bulk refractive index their lasing wavelength could be tuned with a sensitivity of 20 nm/RIU and a LOD of 3×10-6 RIU
In vivo anticancer evaluation of the hyperthermic efficacy of anti-human epidermal growth factor receptor-targeted PEG-based nanocarrier containing magnetic nanoparticles
Polymeric nanoparticles with targeting moieties containing magnetic nanoparticles as theranostic agents have considerable potential for the treatment of cancer. Here we report the chemical synthesis and characterization of a poly(D,L-lactide-co-glycolide)-b-poly(ethylene glycol)-based nanocarrier containing iron oxide nanoparticles and human epithelial growth factor receptor on the outer shell. The nanocarrier was also radiolabeled with 99mTc and tested as a theranostic nanomedicine, ie, it was investigated for both its diagnostic ability in vivo and its therapeutic hyperthermic effects in a standard A431 human tumor cell line. Following radiolabeling with 99mTc, the biodistribution and therapeutic hyperthermic effects of the nanosystem were studied noninvasively in vivo in tumor-bearing mice. A substantial decrease in tumor size correlated with an increase in both nanoparticle concentration and local temperature was achieved, confirming the possibility of using this multifunctional nanosystem as a therapeutic tool for epidermoid carcinoma