19 research outputs found
Rapid Prototyping of 3D Biochips for Cell Motility Studies Using Two-Photon Polymerization
The study of cellular migration dynamics and strategies plays a relevant role in the
understanding of both physiological and pathological processes. An important example
could be the link between cancer cell motility and tumor evolution into metastatic
stage. These strategies can be strongly influenced by the extracellular environment
and the consequent mechanical constrains. In this framework, the possibility to study
the behavior of single cells when subject to specific topological constraints could
be an important tool in the hands of biologists. Two-photon polymerization is a
sub-micrometric additive manufacturing technique that allows the fabrication of 3D
structures in biocompatible resins, enabling the realization of ad hoc biochips for cell
motility analyses, providing different types of mechanical stimuli. In our work, we present
a new strategy for the realization of multilayer microfluidic lab-on-a-chip constructs
for the study of cell motility which guarantees complete optical accessibility and the
possibility to freely shape the migration area, to tailor it to the requirements of the
specific cell type or experiment. The device includes a series of micro-constrictions
that induce different types of mechanical stress on the cells during their migration. We
show the realization of different possible geometries, in order to prove the versatility of
the technique. As a proof of concept, we present the use of one of these devices for the
study of the motility of murine neuronal cancer cells under high physical confinement,
highlighting their peculiar migration mechanisms
Intermediate filaments ensure resiliency of single carcinoma cells, while active contractility of the actin cortex determines their invasive potential
During the epithelial-to-mesenchymal transition, the intracellular cytoskeleton undergoes severe
reorganization which allows epithelial cells to transition into a motile mesenchymal phenotype.
Among the different cytoskeletal elements, the intermediate filaments keratin (in epithelial cells)
and vimentin (in mesenchymal cells) have been demonstrated to be useful and reliable histological
markers. In this study, we assess the potential invasiveness of six human breast carcinoma cell lines
and two mouse fibroblasts cells lines through single cell migration assays in confinement. We find
that the keratin and vimentin networks behave mechanically the same when cells crawl through
narrow channels and that vimentin protein expression does not strongly correlate to single cells
invasiveness. Instead, we find that what determines successful migration through confining spaces
is the ability of cells to mechanically switch from a substrate-dependent stress fibers based
contractility to a substrate-independent cortical contractility, which is not linked to their tumor
phenotype
Characterization of timing and spacial resolution of novel TI-LGAD structures before and after irradiation
The characterization of spacial and timing resolution of the novel Trench
Isolated LGAD (TI-LGAD) technology is presented. This technology has been
developed at FBK with the goal of achieving 4D pixels, where an accurate
position resolution is combined in a single device with the precise timing
determination for Minimum Ionizing Particles (MIPs). In the TI-LGAD technology,
the pixelated LGAD pads are separated by physical trenches etched in the
silicon. This technology can reduce the interpixel dead area, mitigating the
fill factor problem. The TI-RD50 production studied in this work is the first
one of pixelated TI-LGADs. The characterization was performed using a scanning
TCT setup with an infrared laser and a Sr source setup
A retrospective multicentric observational study of trastuzumab emtansine in HER2 positive metastatic breast cancer: A real-world experience
We addressed trastuzumab emtansine (T-DM1) efficacy in HER2+ metastatic breast cancer patients treated in real-world practice, and its activity in pertuzumab-pretreated patients. We conducted a retrospective, observational study involving 23 cancer centres, and 250 patients. Survival data were analyzed by Kaplan Meier curves and log rank test. Factors testing significant in univariate analysis were tested in multivariate models. Median follow-up was 15 months and median T-DM1 treatment-length 4 months. Response rate was 41.6%, clinical benefit 60.9%. Median progression-free and median overall survival were 6 and 20 months, respectively. Overall, no differences emerged by pertuzumab pretreatment, with median progression-free and median overall survival of 4 and 17 months in pertuzumab-pretreated (p=0.13), and 6 and 22 months in pertuzumab-na\uc3\uafve patients (p=0.27). Patients who received second-line T-DM1 had median progression-free and median overall survival of 3 and 12 months (p=0.0001) if pertuzumab-pretreated, and 8 and 26 months if pertuzumab-na\uc3\uafve (p=0.06). In contrast, in third-line and beyond, median progression-free and median overall survival were 16 and 18 months in pertuzumab-pretreated (p=0.05) and 6 and 17 months in pertuzumab-na\uc3\uafve patients (p=0.30). In multivariate analysis, lower ECOG performance status was associated with progression-free survival benefit (p < 0.0001), while overall survival was positively affected by lower ECOG PS (p < 0.0001), absence of brain metastases (p 0.05), and clinical benefit (p < 0.0001). Our results are comparable with those from randomized trials. Further studies are warranted to confirm and interpret our data on apparently lower T-DM1 efficacy when given as second-line treatment after pertuzumab, and on the optimal sequence order
Microfluidic Lab-on-a-Chip for Studies of Cell Migration under Spatial Confinement
Understanding cell migration is a key step in unraveling many physiological phenomena and predicting several pathologies, such as cancer metastasis. In particular, confinement has been proven to be a key factor in the cellular migration strategy choice. As our insight in the field improves, new tools are needed in order to empower biologists’ analysis capabilities. In this framework, microfluidic devices have been used to engineer the mechanical and spatial stimuli and to investigate cellular migration response in a more controlled way. In this work, we will review the existing technologies employed in the realization of microfluidic cellular migration assays, namely the soft lithography of PDMS and hydrogels and femtosecond laser micromachining. We will give an overview of the state of the art of these devices, focusing on the different geometrical configurations that have been exploited to study specific aspects of cellular migration. Our scope is to highlight the advantages and possibilities given by each approach and to envisage the future developments in in vitro migration studies under spatial confinement in microfluidic devices
Intermediate filaments ensure resiliency of single carcinoma cells, while active contractility of the actin cortex determines their invasive potential
During the epithelial-to-mesenchymal transition, the intracellular cytoskeleton undergoes severe
reorganization which allows epithelial cells to transition into a motile mesenchymal phenotype.
Among the different cytoskeletal elements, the intermediate filaments keratin (in epithelial cells)
and vimentin (in mesenchymal cells) have been demonstrated to be useful and reliable histological
markers. In this study, we assess the potential invasiveness of six human breast carcinoma cell lines
and two mouse fibroblasts cells lines through single cell migration assays in confinement. We find
that the keratin and vimentin networks behave mechanically the same when cells crawl through
narrow channels and that vimentin protein expression does not strongly correlate to single cells
invasiveness. Instead, we find that what determines successful migration through confining spaces
is the ability of cells to mechanically switch from a substrate-dependent stress fibers based
contractility to a substrate-independent cortical contractility, which is not linked to their tumor
phenotype