ZIP4 Promotes Muscle Wasting and Cachexia in Mice With Orthotopic Pancreatic Tumors by Stimulating RAB27B-Regulated Release of Extracellular Vesicles From Cancer Cells.

BACKGROUND & AIMS: Cachexia, which includes muscle wasting, is a frequent complication of pancreatic cancer. There are no therapies that reduce cachexia and increase patient survival, so it is important to learn more about its mechanisms. The zinc transporter ZIP4 promotes growth and metastasis of pancreatic tumors. We investigated its effects on muscle catabolism via extracellular vesicle (EV)-mediated stimulation of mitogen-activated protein kinase 14 (p38 MAPK). METHODS: We studied nude mice with orthotopic tumors grown from human pancreatic cancer cell lines (AsPC-1 and BxPC-3); tumors were removed 8 days after cell injection and analyzed by histology. Mouse survival was analyzed by Kaplan-Meier curves. ZIP4 was knocked down in AsPC-1 and BxPC-3 cells with small hairpin RNAs; cells with empty vectors were used as controls. Muscle tissues were collected from mice and analyzed by histology and immunohistochemistry. Conditioned media from cell lines and 3-dimensional spheroid/organoid cultures of cancer cells were applied to C2C12 myotubes. The myotubes and the media were analyzed by immunoblots, enzyme-linked immunosorbent assays, and immunofluorescence microscopy. EVs were isolated from conditioned media and analyzed by immunoblots. RESULTS: Mice with orthotopic tumors grown from pancreatic cancer cells with knockdown of ZIP4 survived longer and lost less body weight and muscle mass than mice with control tumors. Conditioned media from cancer cells activated p38 MAPK, induced expression of F-box protein 32 and UBR2 in C2C12 myotubes, and also led to loss of myofibrillar protein myosin heavy chain and myotube thinning. Knockdown of ZIP4 in cancer cells reduced these effects. ZIP4 knockdown also reduced pancreatic cancer cell release of heat shock protein (HSP) 70 and HSP90, which are associated with EVs, by decreasing CREB-regulated expression of RAB27B. CONCLUSIONS: ZIP4 promotes growth of orthotopic pancreatic tumors in mice and loss of muscle mass by activating CREB-regulated expression of RAB27B, required for release of EVs from pancreatic cancer cells. These EVs activate p38 MAPK and induce expression of F-box protein 32 and UBR2 in myotubes, leading to loss of myofibrillar myosin heavy chain and myotube thinning. Strategies to disrupt these pathways might be developed to reduce pancreatic cancer progression and accompanying cachexia.

Transcanal Endoscopic Ear Surgery for the Management of Congenital Ossicular Fixation.

OBJECTIVES: 1) To describe the technique for transcanal endoscopic management of congenital ossicular chain fixation. 2) To highlight the utility and outcomes of the endoscopic approach for management of congenital ossicular fixation. STUDY DESIGN: Retrospective patient series. SETTING: Academic tertiary pediatric hospital. PATIENTS: Pediatric patients (age 6-12) undergoing transcanal endoscopic management of congenital ossicular fixation from May 2014 to December 2014. INTERVENTIONS: A transcanal endoscopic approach was used in eight procedures. Ossicular chain pathology was managed with either mobilization, ossiculoplasty with a stapes prosthesis, or incus interposition. MAIN OUTCOME MEASURES: Pure-tone averages, speech reception thresholds, and speech discrimination scores were recorded pre- and postoperatively for each subject. Preoperative computed tomography evaluations were compared to intraoperative findings for each subject. RESULTS: An improvement in the pure-tone average, as well as air-bone gap, was noted after six of eight procedures. No patients experienced a complication or a reduction in their bone conduction hearing. The chorda tympani nerve was preserved in all eight patients. Conversion to open approach was not necessary for any of the eight procedures performed. CONCLUSION: The transcanal endoscopic approach was successful in improving hearing in pediatric patients with congenital ossicular fixation that involves any of the three ossicles. An endoscopic transcanal approach provides an alternative method to manage congenital ossicular pathology with the advantage of providing excellent visualization and the avoidance of a postauricular incision.

Transcanal Endoscopic Management of Cerebrospinal Fluid Otorrhea Secondary to Congenital Inner Ear Malformations.

OBJECTIVE: To describe the feasibility of using a transcanal endoscopic approach for management of cerebrospinal leaks secondary to congenital inner ear malformations. PATIENTS: Two pediatric patients with congenital inner ear malformations and concurrent cerebrospinal fluid leakage. INTERVENTION: A stapedectomy was performed and the inner ear was packed with temporalis muscle using a transcanal endoscopic approach. MAIN OUTCOME MEASURE: Cessation of cerebrospinal fluid leakage from the inner ear to the middle ear. RESULTS: An otic capsule malformation with a modiolar defect as well as a defect in the stapes footplate was noted in both patients. Successful repair of cerebrospinal fluid otorrhea was achieved in both patients using a minimally invasive transcanal endoscopic approach. One patient developed postoperative meningitis that was successfully managed with antibiotics. CONCLUSIONS: Cerebrospinal fluid otorrhea from an inner ear malformation often presents as persistent clear otorrhea after tympanostomy tube placement or recurrent meningitis as was the case in the two patients in this series. A minimally invasive transcanal endoscopic approach is a viable alternative to manage this unique entity.

Recurrent cholesteatoma with massive extension to temporoparietal scalp: case report and literature review.

BACKGROUND: Cholesteatomas are locally destructive collections of epithelial debris arising from temporal bone squamous epithelium. Recurrences may occur after removal and are typically located within the temporal bone. OBJECTIVE: This study aimed to report a case of a massive, recurrent cholesteatoma with extension to temporoparietal scalp in a 37-year-old woman. METHODS: Case report with literature review. RESULTS: The patient underwent complete excision of a well-circumscribed left temporal mass, intraoperatively identified to arise from the middle ear and to contain keratin debris. CONCLUSION: We report a case of recurrent cholesteatoma with massive extension to temporoparietal scalp. Clinical suspicion of recurrent cholesteatoma should remain in the differential diagnosis of temporal mass with prior history of cholesteatoma.

A novel epigenetic CREB-miR-373 axis mediates ZIP4-induced pancreatic cancer growth.

Changes in the intracellular levels of the essential micronutrient zinc have been implicated in multiple diseases including pancreatic cancer; however, the molecular mechanism is poorly understood. Here, we report a novel mechanism where increased zinc mediated by the zinc importer ZIP4 transcriptionally induces miR-373 in pancreatic cancer to promote tumour growth. Reporter, expression and chromatin immunoprecipitation assays demonstrate that ZIP4 activates the zinc-dependent transcription factor CREB and requires this transcription factor to increase miR-373 expression through the regulation of its promoter. miR-373 induction is necessary for efficient ZIP4-dependent enhancement of cell proliferation, invasion, and tumour growth. Further analysis of miR-373 in vivo oncogenic function reveals that it is mediated through its negative regulation of TP53INP1, LATS2 and CD44. These results define a novel ZIP4-CREB-miR-373 signalling axis promoting pancreatic cancer growth, providing mechanistic insights explaining in part how a zinc transporter functions in cancer cells and may have broader implications as inappropriate regulation of intracellular zinc levels plays an important role in many other diseases.

ZIP4 is a novel molecular marker for glioma.

BACKGROUND: Dysregulated zinc transport has been observed in many cancers. However, the status of zinc homeostasis and the expression profile of zinc transporters in brain and brain tumors have not been reported. METHODS: The gene profiles of 14 zinc importers (ZIPs) and 10 zinc exporters (ZnTs) in patients with glioma were studied by investigating the association between the zinc transporters and brain tumor characteristics (tumor grade and overall survival time). Three independent cohorts were analyzed to cross-validate the findings: the Chinese Glioma Genome Atlas (CGCA) cohort (n = 186), the US National Cancer Institute Repository for Molecular Brain Neoplasia Data (REMBRANDT) cohort (n = 335), and The University of Texas (UT) cohort (n = 34). RESULTS: The expression of ZIP3, 4, 8, 14, ZnT5, 6, and 7 were increased, and the expression of ZnT10 was decreased in grade IV gliomas, compared with grade II gliomas. Among all 24 zinc transporters, ZIP4 is most significantly associated with tumor grade and overall survival; this finding is consistent across 2 independent cohorts (CGCA and REMBRANDT) and is partially validated by the third cohort (UT). High ZIP4 expression was significantly associated with higher grade of gliomas and shorter overall survival (hazard ratio = 1.61, 95% confidence interval = 1.02-2.53, P = .040 in CGCA cohort; hazard ratio = 1.32, 95% confidence interval = 1.08-1.61, P = .007 in REMBRANDT cohort). CONCLUSIONS: Dysregulated expression of zinc transporters is involved in the progression of gliomas. Our results suggest that ZIP4 may serve as a potential diagnostic and prognostic marker for gliomas.

Deregulated signaling pathways in glioblastoma multiforme: molecular mechanisms and therapeutic targets.

Glioblastoma multiforme (GBM) is the most malignant and aggressive type of brain tumor with an average life expectancy of less than 15 months. This is mostly due to the highly mutated genome of GBM, which is characterized by the deregulation of many key signaling pathways involving growth, proliferation, survival, and apoptosis. It is critical to explore novel diagnostic and therapeutic strategies that target these pathways to improve the treatment of malignant glioma in the future. This review summarizes the most common and important pathways that are highly mutated or deregulated in GBM and discusses potential therapeutic strategies targeting these pathways.

Understanding the role of cytokines in Glioblastoma Multiforme pathogenesis.

Cytokines play a significant role in cancer diagnosis, prognosis and therapy. The immune system's failure to recognize the malignant tumor cells and mount an effective response may be the result of tumor-associated cytokine deregulation. Glioblastoma Multiforme (GBM) has a characteristic cytokine expression pattern, and abnormalities in cytokine expression have been implicated in gliomagenesis. Within the heterogeneous GBM microenvironment, the tumor cells, normal brain cells, immune cells, and stem cells interact with each other through the complex cytokine network. This review summarizes the current understanding of the functions of key cytokines on GBM, and highlights potential therapeutic applications targeting these cytokines.