Reliable and mobile all-fiber modular optical tweezers

Miniaturization and integration of optical tweezers are attractive. Optical fiber-based trapping systems allow optical traps to be realized in miniature systems, but the optical traps in these systems lack reliability or mobility. Here, we present the all-fiber modular optical tweezers (AFMOTs), in which an optical trap can be reliably created and freely moved on a sample substrate. Two inclined optical fibers are permanently fixed to a common board, rendering a modular system where fiber alignments are maintained over months. The freely movable optical trap allows particles to be trapped in their native locations. As a demonstration, we applied AFMOTs to trap and deform freely floating individual cells. By the cell mechanical responses, we differentiated the nontumorigenic breast epithelial cell line (MCF10A) from its cancerous PTEN mutants (MCF10 PTEN-/-). To further expand the functionalities, three modalities of AFMOTs are demonstrated by changing the types of fibers for both the optical trap creation and particle position detection. As a miniature and modular system that creates a reliable and mobile optical trap, AFMOTs can find potential applications ranging from point-of-care diagnostics to education, as well as helping transition the optical trapping technology from the research lab to the field.

Ru(ii)-Naphthoquinone complexes with high selectivity for triple-negative breast cancer

Ru(ii)/lapachol complex shows significant selectivity for triple negative breast cancer (TNBC) compared to the non-tumor human breast epithelial cell line.

Calpain 9 as a therapeutic target in TGFβ-induced mesenchymal transition and fibrosis

Fibrosis is a common pathologic outcome of chronic disease resulting in the replacement of normal tissue parenchyma with a collagen-rich extracellular matrix produced by myofibroblasts. Although the progenitor cell types and cellular programs giving rise to myofibroblasts through mesenchymal transition can vary between tissues and diseases, their contribution to fibrosis initiation, maintenance, and progression is thought to be pervasive. Here, we showed that the ability of transforming growth factor–β (TGFβ) to efficiently induce myofibroblast differentiation of cultured epithelial cells, endothelial cells, or quiescent fibroblasts is dependent on the induced expression and activity of dimeric calpains, a family of non-lysosomal cysteine proteases that regulate a variety of cellular events through posttranslational modification of diverse substrates. siRNA-based gene silencing demonstrated that TGFβ-induced mesenchymal transition of a murine breast epithelial cell line was dependent on induction of expression of calpain 9 (CAPN9), an isoform previously thought to be restricted to the gastrointestinal tract. Mice lacking functional CAPN9 owing to biallelic targeting of Capn9 were viable and fertile but showed overt protection from bleomycin-induced lung fibrosis, carbon tetrachloride–induced liver fibrosis, and angiotensin II–induced cardiac fibrosis and dysfunction. A predicted loss-of-function allele of CAPN9 is common in Southeast Asia, with the frequency of homozygosity matching the prediction of Hardy-Weinberg equilibrium. Together with the highly spatially restricted pattern of CAPN9 expression under physiologic circumstances and the heartiness of the murine knockout, these data provide a strong signature for tolerance of therapeutic strategies for fibrosis aimed at CAPN9 antagonism.

Inferring intracellular signal transduction circuitry from molecular perturbation experiments

The development of network inference methodologies that accurately predict connectivity in dysregulated pathways may enable the rational selection of patient therapies. Accurately inferring an intracellular network from data remains a very challenging problem in molecular systems biology. Living cells integrate extremely robust circuits that exhibit significant heterogeneity, but still respond to external stimuli in predictable ways. This phenomenon allows us to introduce a network inference methodology that integrates measurements of protein activation from perturbation experiments. The methodology relies on logic-based networks to provide a predictive approximation of the transfer of signals in a network. The approach presented was validated in silico with a set of test networks and applied to investigate the epidermal growth factor receptor signaling of a breast epithelial cell line, MFC10A. In our analysis, we predict the potential signaling circuitry most likely responsible for the experimental readouts of several proteins in the mitogen activated protein kinase and phosphatidylinositol-3 kinase pathways. The approach can also be used to identify additional necessary perturbation experiments to distinguish between a set of possible candidate networks.