Signaling pathways governing the maintenance of breast cancer stem cells and their therapeutic implications.

Breast cancer stem cells (BCSCs) represent a distinct subpopulation of cells with the ability to self-renewal and differentiate into phenotypically diverse tumor cells. The involvement of CSC in treatment resistance and cancer recurrence has been well established. Numerous studies have provided compelling evidence that the self-renewal ability of cancer stem cells is tightly regulated by specific signaling pathways, which exert critical roles to maintain an undifferentiated phenotype and prevent the differentiation of CSCs. Signaling pathways such as Wnt/ß-catenin, NF-κB, Notch, Hedgehog, TGF-ß, and Hippo have been implicated in the promotion of self-renewal of many normal and cancer stem cells. Given the pivotal role of BCSCs in driving breast cancer aggressiveness, targeting self-renewal signaling pathways holds promise as a viable therapeutic strategy for combating this disease. In this review, we will discuss the main signaling pathways involved in the maintenance of the self-renewal ability of BCSC, while also highlighting current strategies employed to disrupt the signaling molecules associated with stemness.

Airway Hyperresponsiveness in Asthma Model Occurs Independently of Secretion of ß1 Integrins in Airway Wall and Focal Adhesions Proteins Down Regulation.

The extracellular domains of some membrane proteins can be shed from the cell. A similar phenomenon occurs with ß1 integrins (α1ß1 and α2ß1) in guinea pig. The putative role of ß1 integrin subunit alterations due to shedding in airway smooth muscle (ASM) in an allergic asthma model was evaluated. Guinea pigs were sensitized and challenged with antigen. Antigenic challenges induced bronchoobstruction and hyperresponsiveness at the third antigenic challenge. Immunohistochemistry and immunoelectronmicroscopy studies showed that the cytosolic and extracellular domains of the ß1 integrin subunit shared the same distribution in airway structures in both groups. Various polypeptides with similar molecular weights were detected with both the cytosolic and extracellular ß1 integrin subunit antibodies in isolated airway myocytes and the connective tissue that surrounds the ASM bundle. Flow cytometry and Western blot studies showed that the expression of cytosolic and extracellular ß1 integrin subunit domains in ASM was similar between groups. An increment of ITGB1 mRNA in ASM was observed in the asthma model group. RACE-PCR of ITGB1 in ASM did not show splicing variants. The expression levels of integrin-linked kinase (ILK) and paxillin diminished in the asthma model, but not talin. The levels of phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Thr(696) increased in asthma model. Our work suggests that ß1 integrin is secreted in guinea pig airway wall. This secretion is not altered in asthma model; nevertheless, ß1 integrin cytodomain assembly proteins in focal cell adhesions in which ILK and paxillin are involved are altered in asthma model. J. Cell. Biochem. 117: 2385-2396, 2016. © 2016 Wiley Periodicals, Inc.

Neutrophilia induced by histamine challenge in guinea pig: The role of IL-5, IL-10 and IL-17A, but not CXCL8

Background: Histamine is widely used as a pharmacological tool for the evaluation of airway responsiveness. Nevertheless, undesirable and contradictory effects have been described after histamine provocation tests. In previous evaluations of airway responsiveness in a guinea pig asthma model, the control groups consistently showed high neutrophil counts in bronchoalveolar lavage fluid (BALF) immediately after the histamine challenge. The changes in cytokine and chemokine levels in guinea pig lung associated with histamine induced-neutrophilia are described in this paper. Methods: Immediately and 24 h after histamine challenge, airway wall and BALF eosinophil and neutrophil counts as well as lung cytokines (IL-5, IL-10, IL-17A, TNFα and TGFβ) and chemokines (CCL11 and CXCL8) levels were evaluated. Results: Histamine inhalation generated an all-or-none bronchial response, and the dose inducing airway obstruction was similar in all guinea pigs. Immediate increases in neutrophil counts in airway wall and BALF and in IL-5, IL-10 and IL-17A levels in the lung homogenate were observed after histamine challenge. Significant correlations were found between neutrophil counts from airway wall and IL-5, IL-10 and IL-17A levels in the lung homogenate. Conclusions: Histamine inhalation induced rapid neutrophil LBA and airway wall infiltration that was not associated with CXCL8 expression but with a Th2 and Th17 cytokines that probably are involved in the recruitment and activation of neutrophils.