ABSTRACT
Cancer cells secrete pronociceptive mediators that sensitize adjacent sensory neurons and cause pain. Identification and characterization of these mediators could pinpoint novel targets for cancer pain treatment. In this study, we identified candidate genes in cancer cell lines that encode for secreted or cell surface proteins that may drive nociception. To undertake this work, we used an acute cancer pain mouse model, transcriptomic analysis of publicly available human tumor-derived cell line data, and a literature review. Cancer cell line supernatants were assigned a phenotype based on evoked nociceptive behavior in an acute cancer pain mouse model. We compared gene expression data from nociceptive and nonnociceptive cell lines. Our analyses revealed differentially expressed genes and pathways; many of the identified genes were not previously associated with cancer pain signaling. Epidermal growth factor receptor (EGFR) and disintegrin metalloprotease domain 17 (ADAM17) were identified as potential targets among the differentially expressed genes. We found that the nociceptive cell lines contained significantly more ADAM17 protein in the cell culture supernatant compared to nonnociceptive cell lines. Cytoplasmic EGFR was present in almost all (>90%) tongue primary afferent neurons in mice. Monoclonal antibody against EGFR, cetuximab, inhibited cell line supernatant-induced nociceptive behavior in an acute oral cancer pain mouse model. We infer from these data that ADAM17-EGFR signaling is involved in cancer mediator-induced nociception. The differentially expressed genes and their secreted protein products may serve as candidate therapeutic targets for oral cancer pain and warrant further evaluation.
Subject(s)
Cancer Pain , Neoplasms , ADAM17 Protein/genetics , ADAM17 Protein/metabolism , Animals , Cancer Pain/genetics , Cell Line, Tumor , Disintegrins , ErbB Receptors/genetics , ErbB Receptors/metabolism , Mice , Signal TransductionABSTRACT
The palate functions as the roof of the mouth in mammals, separating the oral and nasal cavities. Its complex embryonic development and assembly poses unique susceptibilities to intrinsic and extrinsic disruptions. Such disruptions may cause failure of the developing palatal shelves to fuse along the midline resulting in a cleft. In other cases the palate may fuse at an arch, resulting in a vaulted oral cavity, termed high-arched palate. There are many models available for studying the pathogenesis of cleft palate but a relative paucity for high-arched palate. One condition exhibiting either cleft palate or high-arched palate is Treacher Collins syndrome, a congenital disorder characterized by numerous craniofacial anomalies. We quantitatively analyzed palatal perturbations in the Tcof1(+/-) mouse model of Treacher Collins syndrome, which phenocopies the condition in humans. We discovered that 46% of Tcof1(+/-) mutant embryos and new born pups exhibit either soft clefts or full clefts. In addition, 17% of Tcof1(+/-) mutants were found to exhibit high-arched palate, defined as two sigma above the corresponding wild-type population mean for height and angular based arch measurements. Furthermore, palatal shelf length and shelf width were decreased in all Tcof1(+/-) mutant embryos and pups compared to controls. Interestingly, these phenotypes were subsequently ameliorated through genetic inhibition of p53. The results of our study therefore provide a simple, reproducible and quantitative method for investigating models of high-arched palate.
Subject(s)
Maxillofacial Development/physiology , Nuclear Proteins/genetics , Palate/abnormalities , Phosphoproteins/genetics , Animals , Cleft Palate/diagnostic imaging , Cleft Palate/embryology , Cleft Palate/genetics , Crosses, Genetic , Disease Models, Animal , Female , Gene Knockout Techniques , Genes, p53 , Heterozygote , Humans , Imaging, Three-Dimensional , Intracellular Signaling Peptides and Proteins , Male , Mandibulofacial Dysostosis/diagnostic imaging , Mandibulofacial Dysostosis/embryology , Mandibulofacial Dysostosis/genetics , Maxillofacial Development/genetics , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Microscopy, Confocal , Nuclear Proteins/physiology , Palate/diagnostic imaging , Palate/embryology , Phenotype , Phosphoproteins/physiology , Species SpecificityABSTRACT
Ferritin is a 24-subunit molecule, made up of heavy chain (HC) and light chain (LC) subunits, which stores and controls the release of dietary iron in mammals, plants, and insects. In mosquitoes, dietary iron taken in a bloodmeal is stored inside ferritin. Our previous work has demonstrated the transport of dietary iron to the ovaries via ferritin during oogenesis. We evaluated the localization of ferritin subunits inside CCL-125 [Aedes aegypti Linnaeus (Diptera: Culicidae), yellow fever mosquito] and 4a3b [Anopheles gambiae Giles (Diptera: Culicidae), African malaria mosquito] cells under various iron treatment conditions to further elucidate the regulation of iron metabolism in these important disease vectors and to observe the dynamics of the intracellular ferritin subunits following iron administration. Deconvolution microscopy captured 3D fluorescent images of iron-treated mosquito cells to visualize the ferritin HC and LC homologue subunits (HCH and LCH, respectively) in multiple focal planes. Fluorescent probes were used to illuminate cell organelles (i.e., Golgi apparatus, lysosomes, and nuclei) while secondary probes for specific ferritin subunits demonstrated abundance and co-localization within organelles. These images will help to develop a model for the biochemical regulation of ferritin under conditions of iron exposure, and to advance novel hypotheses for the crucial role of iron in mosquito vectors.
