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Even though the majority of breast cancers respond well to primary therapy, a large percentage of patients relapse with metastatic disease, for which there is no treatment. In metastasis, a tumor sheds a small number of cancerous cells, termed circulating tumor cells (CTCs), into the local vasculature, from where they spread throughout the body to form new tumors. As CTCs move through the circulatory system, they experience physiological forces not present in the initial tumor environment, namely, fluid shear stress (FSS). Evidence suggests that CTCs respond to FSS by adopting a more aggressive phenotype; however, to date single-cell morphological changes have not been quantified to support this observation. Furthermore, the methodology of previous studies involves inducing FSS by flowing cells through the tubing, which lacks a precise and tunable control of FSS. Here, a microfluidic approach is used for isolating and characterizing the biophysical response of single breast cancer cells to conditions experienced in the circulatory system during metastasis. To evaluate the single-cell response of multiple breast cancer types, two model circulating tumor cell lines, MDA-MB-231 and MCF7, were challenged with FSS at precise magnitudes and durations. As expected, both MDA-MB-231 and MCF7 cells exhibited greater deformability due to increasing duration and magnitudes of FSS. However, wide variations in single-cell responses were observed. MCF7 cells were found to rapidly deform but reach a threshold value after 5 min of FSS, while MDA-MB-231 cells were observed to deform at a slower rate but with a larger threshold of deformation. This behavioral diversity suggests the presence of distinct cell subpopulations with different phenotypes. [ABSTRACT FROM AUTHOR]

Aim: To investigate whether p38 small-interfering RNA-loaded nanoparticles (p38 siRNA NPs) attenuate spinal nerve ligation (SNL)-induced neuropathic pain in rats by suppressing spinal microglia activation via p38 targeting. Materials & methods: After synthesizing p38 siRNA NPs with sonication, physical characteristics were measured for size and zeta potential. p38 siRNA NPs were then administrated intrathecally into SNL rats if they could reduce pain behavior excellently. Results: p38 siRNA NPs significantly reduced mechanical allodynia as well as microgliosis in the spinal dorsal horns of SNL rats, consistent with a downregulation of p38-related proinflammatory mediators. Conclusion: 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Akt (also known as protein kinase B, PKB) has been seen to play a role in astrocyte activation of neuroprotection; however, the underlying mechanism on deregulation of Akt signaling in brain injuries is not fully understood. We investigated the role of carboxy-terminal modulator protein (CTMP), an endogenous Akt inhibitor, in brain injury following kainic acid (KA)-induced neurodegeneration of mouse hippocampus. In control mice, there was a weak signal for CTMP in the hippocampus, but CTMP was markedly increased in the astrocytes 3 days after KA treatment. To further investigate the effectiveness of Akt signaling, the phosphorylation of CTMP was examined. KA treatment induced an increased p-CTMP expression in the astrocytes of hippocampus at 1 day. LPS/IFN-γ-treatment on primary astrocytes promoted the p-CTMP was followed by phosphorylation of Akt and finally upregulation of CTMP and p-CREB. Time-dependent expression of p-CTMP, p-Akt, p-CREB, and CTMP indicate that LPS/IFN-γ-induced phosphorylation of CTMP can activate Akt/CREB signaling, whereas lately emerging enhancement of CTMP can inhibit it. These results suggest that elevation of CTMP in the astrocytes may suppress Akt activity and ultimately negatively affect the outcome of astrocyte activation (astroglisiois). Early time point enhancers of phosphorylation of CTMP and/or late time inhibitors specifically targeting CTMP may be beneficial in astrocyte activation for neuroprotection within treatment in neuroinflammatory conditions.