Cortisol promotes breast-to-brain metastasis through the blood-cerebrospinal fluid barrier.

BACKGROUND: Elevated basal cortisol levels are present in women with primary and metastatic breast cancer. Although cortisol's potential role in breast-to-brain metastasis has yet to be sufficiently studied, prior evidence indicates that it functions as a double-edged sword-cortisol induces breast cancer metastasis in vivo, but strengthens the blood-brain-barrier (BBB) to protect the brain from microbes and peripheral immune cells. AIMS: In this study, we provide a novel examination on whether cortisol's role in tumor invasiveness eclipses its supporting role in strengthening the CNS barriers. We expanded our study to include the blood-cerebrospinal fluid barrier (BCSFB), an underexamined site of tumor entry. METHODS AND RESULTS: Utilizing in vitro BBB and BCSFB models to measure barrier strength in the presence of hydrocortisone (HC). We established that lung tumor cells migrate through both CNS barriers equally while breast tumors cells preferentially migrate through the BCSFB. Furthermore, HC treatment increased breast-to-brain metastases (BBM) but not primary breast tumor migratory capacity. When examining the transmigration of breast cancer cells across the BCSFB, we demonstrate that HC induces increased traversal of BBM but not primary breast cancer. We provide evidence that HC increases tightness of the BCSFB akin to the BBB by upregulating claudin-5, a tight junction protein formerly acknowledged as exclusive to the BBB. CONCLUSION: Our findings indicate, for the first time that increased cortisol levels facilitate breast-to-brain metastasis through the BCSFB-a vulnerable point of entry which has been typically overlooked in brain metastasis. Our study suggests cortisol plays a pro-metastatic role in breast-to-brain metastasis and thus caution is needed when using glucocorticoids to treat breast cancer patients.

Neuronal exposure induces neurotransmitter signaling and synaptic mediators in tumors early in brain metastasis.

BACKGROUND: Brain metastases (BM) are responsible for neurological decline and poor overall survival. Although the pro-metastatic roles of glial cells, and the acquisition of neuronal attributes in established BM tumors have been described, there are no studies that investigate the initial interplay between neurons and brain-seeking tumor cells. The aim of this study was to characterize early tumor-neuron interactions and the induced CNS-adaptive changes in tumor cells prior to macro-colonization. METHODS: Utilizing pure neuronal cultures and brain-naïve and patient-derived BM tumor cells, we surveyed the early induction of mediators of neurotransmitter (NT) and synaptic signaling in breast and lung tumor cells. Reliance on microenvironmental GABA in breast-to-brain metastatic cells (BBMs) was assessed in vitro and in vivo. RESULTS: Coculture with neurons induces early expression of classical NT receptor genes (HTR4, GRIA2, GRIN2B, GRM4, GRM8, DRD1) and neuronal synaptic mediators (CNR1, EGR2, ARC, NGFR, NRXN1) in breast and lung cancer cells. NT-dependent classification of tumor cells within the neuronal niche shows breast cancer cells become GABAergic responsive brain metastases (GRBMs) and transition from relying on autocrine GABA, to paracrine GABA from adjacent neurons; while autocrine Dopaminergic breast and lung tumor cells persist. In vivo studies confirm reliance on paracrine GABA is an early CNS-acclimation strategy in breast cancer. Moreover, neuronal contact induces early resurgence in Reelin expression in tumor cells through epigenetic activation, facilitating CNS adaptation. CONCLUSION: Tumor-neuron interactions allow for CNS adaptation early in the course of brain metastasis.

Risk Factors for Plate Extrusion After Mandibular Reconstruction With Vascularized Free Flap.

PURPOSE: Plate extrusion after mandibular reconstruction is a complication that imposes significant morbidity on the patient. The goal of this study is to estimate the incidence of plate extrusion after mandible reconstruction with a vascularized free flap and to identify the factors associated with plate extrusion. METHODS: This was a retrospective cohort study involving patients who underwent mandibular reconstruction from October 2008 to July 2019 at LAC + USC or Keck Hospital of USC. Inclusion criteria were age ≥ 18 years, single-stage mandibular reconstruction with vascularized free flap, and follow-up of at least 12 months. Relevant demographic, intraoperative, and postoperative data were collected. The primary outcome was postoperative plate extrusion within the 12-month follow-up. Descriptive, univariate, and multivariate analyses were performed. Statistical significance was set at P ≤ .05. RESULTS: A total of 102 patients were included in this study. The majority received a fibula free flap (90%) for a malignant neoplasm (76%). All patients had at least 12 months of follow-up. The rate of plate extrusion was 16%, with the majority of those patients undergoing plate removal (69%). After adjusting for postoperative fistula, soft tissue, and length of hospitalization, we found that any history of smoking (odds ratio = 12.8; confidence interval, 1.57 to 104.2), number of osteotomies (odds ratio 3.07; confidence interval, 1.09 to 8.6), flap nonviability (odds ratio = 18.2; confidence interval, 2.22 to 148.8) were associated with plate extrusion on multivariate analysis. Postoperative soft tissue infection approached significance. CONCLUSIONS: This study demonstrates that smoking history, number of osteotomies, and flap nonviability are associated with plate extrusion after mandible reconstruction. Performing fewer osteotomies when possible to avoid excessively small flap bone segments and minimizing postoperative complications may improve long-term outcomes after mandibular reconstruction.

Comorbid depression associated with non-routine discharge following craniotomy for low-grade gliomas and benign tumors - a nationwide readmission database analysis.

PURPOSE: Prior studies have demonstrated elevated rates of depression in patients with malignant brain tumor; however, the prevalence and effect on surgical outcomes in patients with low-grade gliomas (LGG) and benign brain tumors (BBT) remain unknown. Readmission and non-routine discharge, which includes discharge to skilled nursing, rehabilitative, and other inpatient facilities, are well-established quality of care indicators. We sought to analyze the association between comorbid depression and non-routine discharge, readmission, and other post-operative inpatient outcomes in patients with LGG and BBT. METHODS: The Nationwide Readmissions Database from 2010 to 2014 was retrospectively queried to select for surgically treated patients with LGG and BBT. Multivariable logistic regression models adjusting for patient and hospital characteristics were used to determine the effects of comorbid depression on post-operative outcomes. Interaction of gender and depression on non-routine disposition was analyzed. RESULTS: We identified 31,654 craniotomies for resection of BBT and LGG (2010-2014). The majority of patients (64.1%) were female. The rate of depression comorbid with BBT and LGG was 11.9%. Depression was associated with non-routine discharge after surgery (OR 1.19, p 0.0002*), but was not associated with increased morbidity, mortality, or readmission at 30 or 90 days. The rate of comorbid depression was higher among female than male patients (14.0 vs. 8.0%). Depression in males was associated with a 38% increased likelihood of non-routine disposition (p = 0.0002*), while depression in females was associated with a 13% increased likelihood of non-routine disposition (p = 0.03*). CONCLUSION: Depression is prevalent in patients with LGG and BBT and is associated with increased risk of non-routine discharge following surgical intervention. The increased likelihood of non-routine disposition is greater for males than that for females. Awareness of the risk factors for depression may aid in early screening and intervention and improve overall patient outcomes.

Isolation of Neural Stem Cells from Whole Brain Tissues of Adult Mice.

A population of neural stem cells exists in the adult mammalian central nervous system. Purification and characterization of neurospheres provide valuable tools to study the regulation and differentiation of neural stem cells both in vitro and in vivo. Successful stimulation and production of neurospheres can ultimately be used for therapeutic purposes. The currently available methods are limited by their poor yield and the large number of animals required to compensate for that. Here, we describe a procedure to purify neurospheres from adult mouse whole brain. We provide detailed steps on how to propagate, passage, and maintain the adult neurospheres, and how to differentiate the pure neurospheres into the lineage of interest. Using this method, neurospheres can be easily derived from adult mouse whole brain. The derived adult neurospheres maintain their homogenous undifferentiated status while retaining their differentiation potential. This new protocol facilitates adult neurospheres isolation, purification, maintenance, and differentiation. © 2019 by John Wiley & Sons, Inc.