Crosstalk between focal adhesions and material mechanical properties governs cell mechanics and functions

Mechanical properties of materials strongly influence cell fate and functions. Focal adhesions are involved in the extremely important processes of mechanosensing and mechanotransduction. To address the relationship between the mechanical properties of cell substrates, focal adhesion/cytoskeleton assembly and cell functions, we investigated the behavior of NIH/3T3 cells over a wide range of stiffness (3-1000 kPa) using two of the most common synthetic polymers for cell cultures: polyacrylamide and polydimethylsiloxane. An overlapping stiffness region was created between them to compare focal adhesion characteristics and cell functions, taking into account their different time-dependent behavior. Indeed, from a rheological point of view, polyacrylamide behaves like a strong gel (elastically), whereas polydimethylsiloxane like a viscoelastic solid. First, focal adhesion characteristics and dynamics were addressed in terms of material stiffness, then cell spreading area, migration rate and cell mechanical properties were correlated with focal adhesion size and assembly. Focal adhesion size was found to increase in the whole range of stiffness and to be in agreement in the overlapping rigidity region for the investigated materials. Cell mechanics directly correlated with focal adhesion lengths, whereas migration rate followed an inverse correlation. Cell spreading correlated with the substrate stiffness on polyacrylamide hydrogel, while no specific trend was found on polydimethylsiloxane. Substrate mechanics can be considered as a key physical cue that regulates focal adhesion assembly, which in turn governs important cellular properties and functions

Investigation on specific solutions of Gerchberg-Saxton algorithm

The most popular method used to generate the Computer Generated Holograms (CGH) is the Gerchberg-Saxton (GS) algorithm. GS computes an approximation of the desired beam shape, and consequently, some distortions may arise. Although many algorithms have been proposed, exact methods to overcome the problem completely do not yet exist. Here we show, for the first time to best of our knowledge, that in some specific configurations exact solutions of the GS algorithm can be achieved so as to produce a limited number of light intensity spots in a clean array. The basic concept is described and both numerical as well as experimental implementations are provided

NCL Inhibition Exerts Antineoplastic Effects against Prostate Cancer Cells by Modulating Oncogenic MicroRNAs

Prostate cancer (PCa) is the most frequently diagnosed cancer in men and second most common cause of cancer-related deaths in the United States. Androgen deprivation therapy (ADT) is only temporarily effective for advanced-stage PCa, as the disease inevitably progresses to castration-resistant prostate cancer (CRPC). The protein nucleolin (NCL) is overexpressed in several types of human tumors where it is also mislocalized to the cell surface. We previously reported the identification of a single-chain fragment variable (scFv) immuno-agent that is able to bind NCL on the surface of breast cancer cells and inhibit proliferation both in vitro and in vivo. In the present study, we evaluated whether NCL could be a valid therapeutic target for PCa, utilizing DU145, PC3 (CRPC), and LNCaP (androgen-sensitive) cell lines. First, we interrogated the publicly available databases and noted that higher NCL mRNA levels are associated with higher Gleason Scores as well as with recurrent and metastatic tumors. Then, using our anti-NCL scFv, we demonstrated that NCL is expressed on the surface of all three tested cell lines and that NCL inhibition results in reduced proliferation and migration. We also measured the inhibitory effect of NCL targeting on the biogenesis of oncogenic microRNAs such as miR-21, -221 and -222, which was cell context dependent. Taken together, our data provide evidence that NCL targeting inhibits the key hallmarks of malignancy in PCa cells and may provide a novel therapeutic option for patients with advanced-stage PCa