Metastasis is the leading cause of cancer deaths due to the spread of cancer cells through the blood vessels and the subsequent formation of secondary tumors. Metastasizing cancer cells in the human vasculature are called circulating tumor cells (CTCs) and are characterized to express the epithelial cell adhesion molecule (EpCAM). They are further known to survive physiological fluid shear stress (FSS) conditions. However, the effect of FSS on CTC molecular phenotype, such as the epithelial to mesenchymal transition (EMT) and cancer stem cell (CSC) expression, has not been extensively studied. Here, CTCs in FSS are evaluated in an in vitro model system. MCF7 and MDA-MB-231 breast cancer cell lines were grown in adherent and suspension culture media. The cell lines were tested for EMT and CSC genetic and protein markers using qRT-PCR and flow cytometry, respectively. Suspension cells showed a significantly increased EMT signature compared to adherent cells (p<0.05), suggesting that they model cells detaching from primary tumors in vivo. Upon application of FSS, MCF7 and MDA-MB-231 cells did not show a significant change in EMT expression (p>0.05), but there was a statistically significant increase of the CSC population in MCF7 suspension cultures (p<0.05). These results with MCF7 suggest that CTCs can be modeled in vitro as non-adherent cancer cells in FSS and that they show an increased CSC-like signature during circulation, providing new insights to the importance of CSC-targeting strategies when treating metastatic patients.

As p38 in the spinal microglia plays a critical role in neuropathic pain, we expect that p38 siRNA NPs could be a promising tool for the treatment of neuropathic pain.

Due to their stem-like characteristics and their resistance to existing chemo- and radiation therapies, there is a growing appreciation that cancer stem cells (CSCs) are the root cause behind cancer metastasis and recurrence. However, these cells represent a small subpopulation of cancer cells and are difficult to propagate in vitro. Glioblastoma is an extremely deadly form of brain cancer that is hypothesized to have a subpopulation of CSCs called glioblastoma stem cells (GSCs; also called brain tumor initiating cells, BTICs). We propose the use of selective Rho-kinase (ROCK) inhibitors, Y-27632 and fasudil, to promote GSC/BTIC-like cell survival and propagation in vitro. ROCK inhibitors have been implicated in suppressing apoptosis, and it was hypothesized that they would increase the number of GSC/BTIC-like cells grown in vitro and improve cloning efficiencies. Indeed, our data demonstrate that transient and continuous supplementation of non-toxic concentrations of Y-27632 and fasudil inhibited apoptosis, enhanced the cells’ ability to form spheres, and increased stem cell marker expressing GSC/BTIC-like cell subpopulation. Our data indicated that pharmacological and genetic (siRNA) inhibitions of the ROCK pathway facilitates in vitro expansion of GSC/BTIC-like cells. Thus, ROCK pathway inhibition shows promise for future optimization of CSC culture media.

Circulating tumor cells (CTCs) are known to have cancer stem cell (CSC) properties and survive physiological conditions of fluid shear stress (FSS). However, current chemotherapy screening techniques do not adequately recapitulate this FSS environment and are not predictive of a drug response. In this study, MCF7 and MDA-MB-231 cells under FSS are used as an in vitro model of CTCs. The effects of doxorubicin (DOX) and paclitaxel on sheared cells using WST8 assay and stemness (CD44 + /CD24 − ) and apoptosis (Annexin V + /7-AAD + ) using flow cytometry are tested. Quantitative polymerase chain reaction is used to test gene expression. It is shown that suspension-cultured and FSS treated MCF7 cells increase in drug resistance, especially with DOX. There is a synergistic increase in the CD44 + /CD24 − CSC-like population and an increase in drug resistance-related gene expression in MCF7 cells co-treated with FSS and drugs. There is also a correlated increase in STAT3 and NANOG expression under FSS. To the best of the authors' knowledge, this is the first report to suggest that the increase in CSC-like cells from FSS contributes to drug resistance via the STAT3/NANOG pathway.This increase in CTC drug resistance also highlights the importance of implementing FSS, which is unavailable in current drug screening techniques.

We propose a novel mechanism of uncoupled eNOS and NO contribution to Tau phosphorylation and AT formation in rmTBI brain, toward an increased molecular understanding of the pathophysiology of human CTE. Antioxid. Redox Signal. 00, 000-000.