Connexin 43 mediated gap junctional communication enhances breast tumor cell diapedesis in culture

INTRODUCTION: Metastasis involves the emigration of tumor cells through the vascular endothelium, a process also known as diapedesis. The molecular mechanisms regulating tumor cell diapedesis are poorly understood, but may involve heterocellular gap junctional intercellular communication (GJIC) between tumor cells and endothelial cells. METHOD: To test this hypothesis we expressed connexin 43 (Cx43) in GJIC-deficient mammary epithelial tumor cells (HBL100) and examined their ability to form gap junctions, establish heterocellular GJIC and migrate through monolayers of human microvascular endothelial cells (HMVEC) grown on matrigel-coated coverslips. RESULTS: HBL100 cells expressing Cx43 formed functional heterocellular gap junctions with HMVEC monolayers within 30 minutes. In addition, immunocytochemistry revealed Cx43 localized to contact sites between Cx43 expressing tumor cells and endothelial cells. Quantitative analysis of diapedesis revealed a two-fold increase in diapedesis of Cx43 expressing cells compared to empty vector control cells. The expression of a functionally inactive Cx43 chimeric protein in HBL100 cells failed to increase migration efficiency, suggesting that the observed up-regulation of diapedesis in Cx43 expressing cells required heterocellular GJIC. This finding is further supported by the observation that blocking homocellular and heterocellular GJIC with carbenoxolone in co-cultures also reduced diapedesis of Cx43 expressing HBL100 tumor cells. CONCLUSION: Collectively, our results suggest that heterocellular GJIC between breast tumor cells and endothelial cells may be an important regulatory step during metastasis

Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors

Context Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs). Objective To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients. Design 12-year prospective, observational study. Participants & Setting We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases. Interventions & Outcome AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310). Results Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650). Conclusions Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course

[14C]-Pyrene Bound Residue Evaluation Using MIBK Fractionation Method for Creosote-Contaminated Soil

The fate of [14C]pyrene was evaluated in creosote-contaminated soil undergoing remediation in a prepared bed system at the Champion International Superfund site in Libby, MT. 14C-bound residue formation was evaluated using the methyl isobutyl ketone (MIBK) humic fractionation procedure, and it increased through 294 days of incubation in biologically active microcosms for humic acid, fulvic acid, bound humic acid, and mineral-associated organic carbon fractions. The relative affinity of the added pyrene and transformation products was highest for the humic acid fraction. Bound residue formation in PAH-contaminated soil was observed to be an important fate mechanism in the prepared bed system and may be an acceptable end point in the remediation of contaminated soil

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-degrading Mycobacterium Isolates from Soil

Bioremediation of soils contaminated with wood preservatives containing polycyclic aromatic hydrocarbons (PAHs) is desired because of their toxic, mutagenic, and carcinogenic properties. Creosote wood preservative–contaminated soils at the Champion International Superfund Site in Libby, Montana currently undergo bioremediation in a prepared-bed land treatment unit (LTU) process. Microbes isolated from these LTU soils rapidly mineralized the 14C-labeled PAH pyrene in the LTU soil. Gram staining, electron microscopy, and 16S rDNA-sequencing revealed that three of these bacteria, JLS, KMS, and MCS, were Mycobacterium strains. The phylogeny of the 16S rDNA showed that they were distinct from other Mycobacterium isolates with PAH-degrading activities. Catalase and superoxide dismutase (SOD) isozyme profiles confirmed that each isolate was distinct from each other and from the PAH-degrading mycobacterium, Mycobacterium vanbaalenii sp. nov, isolated from a petroleum-contaminated soil. We find that dioxygenase genes nidA and nidB are present in each of the Libby Mycobacterium isolates and are adjacent to each other in the sequence nidB-nidA, an order that is unique to the PAH-degrading mycobacteria