The extracellular matrix protein fibulin-3/EFEMP1 promotes pleural mesothelioma growth by activation of PI3K/Akt signaling.

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis and limited therapeutic options. The extracellular matrix protein fibulin-3/EFEMP1 accumulates in the pleural effusions of MPM patients and has been proposed as a prognostic biomarker of these tumors. However, it is entirely unknown whether fibulin-3 plays a functional role on MPM growth and progression. Here, we demonstrate that fibulin-3 is upregulated in MPM tissue, promotes the malignant behavior of MPM cells, and can be targeted to reduce tumor progression. Overexpression of fibulin-3 increased the viability, clonogenic capacity and invasion of mesothelial cells, whereas fibulin-3 knockdown decreased these phenotypic traits as well as chemoresistance in MPM cells. At the molecular level, fibulin-3 activated PI3K/Akt signaling and increased the expression of a PI3K-dependent gene signature associated with cell adhesion, motility, and invasion. These pro-tumoral effects of fibulin-3 on MPM cells were disrupted by PI3K inhibition as well as by a novel, function-blocking, anti-fibulin-3 chimeric antibody. Anti-fibulin-3 antibody therapy tested in two orthotopic models of MPM inhibited fibulin-3 signaling, resulting in decreased tumor cell proliferation, reduced tumor growth, and extended animal survival. Taken together, these results demonstrate for the first time that fibulin-3 is not only a prognostic factor of MPM but also a relevant molecular target in these tumors. Further development of anti-fibulin-3 approaches are proposed to increase early detection and therapeutic impact against MPM.

Resection of a large presacral schwannoma from an all-posterior trans-sacral approach.

BACKGROUND: Presacral schwannomas vary greatly in size, and symptomatology. Resections may utilize anterior, posterior, or combined 360-degree approaches. CASE DESCRIPTION: A 67-year-old female presented with a progressively enlarging presacral schwannoma originating from the S1 nerve root. Here, we utilized a unique all-posterior, trans-sacral tumor resection technique that did not result in any increased neurological deficit, or warrant fusion (e.g., including operative video). Further, we avoided potential urogenital, vascular, and bowel injuries that are associated with anterior approaches to such lesions. CONCLUSION: Here, we described and demonstrated successful resection of a large presacral schwannoma originating from the S1 nerve root that was safely resected utilizing an all-posterior resection without fusion.

Reelin Deficiency Delays Mammary Tumor Growth and Metastatic Progression.

Reelin is a regulator of cell migration in the nervous system, and has other functions in the development of a number of non-neuronal tissues. In addition, alterations in reelin expression levels have been reported in breast, pancreatic, liver, gastric, and other cancers. Reelin is normally expressed in mammary gland stromal cells, but whether stromal reelin contributes to breast cancer progression is unknown. Herein, we used a syngeneic mouse mammary tumor transplantation model to examine the impact of host-derived reelin on breast cancer progression. We found that transplanted syngeneic tumors grew more slowly in reelin-deficient (rl Orl -/- ) mice and had delayed metastatic colonization of the lungs. Immunohistochemistry of primary tumors revealed that tumors grown in rl Orl -/- animals had fewer blood vessels and increased macrophage infiltration. Gene expression studies from tumor tissues indicate that loss of host-derived reelin alters the balance of M1- and M2-associated macrophage markers, suggesting that reelin may influence the polarization of these cells. Consistent with this, rl Orl -/- M1-polarized bone marrow-derived macrophages have heightened levels of the M1-associated cytokines iNOS and IL-6. Based on these observations, we propose a novel function for the reelin protein in breast cancer progression.

A Complex Interaction Between Reduced Reelin Expression and Prenatal Organophosphate Exposure Alters Neuronal Cell Morphology.

Genetic and environmental factors are both likely to contribute to neurodevelopmental disorders including schizophrenia, autism spectrum disorders, and major depressive disorders. Prior studies from our laboratory and others have demonstrated that the combinatorial effect of two factors-reduced expression of reelin protein and prenatal exposure to the organophosphate pesticide chlorpyrifos oxon-gives rise to acute biochemical effects and to morphological and behavioral phenotypes in adolescent and young adult mice. In the current study, we examine the consequences of these factors on reelin protein expression and neuronal cell morphology in adult mice. While the cell populations that express reelin in the adult brain appear unchanged in location and distribution, the levels of full length and cleaved reelin protein show persistent reductions following prenatal exposure to chlorpyrifos oxon. Cell positioning and organization in the hippocampus and cerebellum are largely normal in animals with either reduced reelin expression or prenatal exposure to chlorpyrifos oxon, but cellular complexity and dendritic spine organization is altered, with a skewed distribution of immature dendritic spines in adult animals. Paradoxically, combinatorial exposure to both factors appears to generate a rescue of the dendritic spine phenotypes, similar to the mitigation of behavioral and morphological changes observed in our prior study. Together, our observations support an interaction between reelin expression and chlorpyrifos oxon exposure that is not simply additive, suggesting a complex interplay between genetic and environmental factors in regulating brain morphology.