Iron, hepcidin, and microcytosis in canine hepatocellular carcinoma

Abstract

Background: Erythrocyte microcytosis in some dogs with hepatocellular carcinoma (HCC) suggests a derangement in systemic iron. Hepcidin, the master regulator of iron, is secreted by the liver in response to interleukin 6 (IL-6) and/or bone morphogenetic protein 6 (BMP6) and can cause microcytosis.Objectives: Pilot study to compare the quantities of hepcidin, IL-6, and BMP6 RNA molecules in archival tumoral (HCC) and adjacent peritumoral (non-HCC) hepatic tissue to determine if they are different between tissue types or associated with microcytosis.Methods: RNA was isolated from formalin-fixed, paraffin-embedded HCC and non-HCC tissue from seven microcytic dogs and four normocytic dogs. Digital RNA counts of hepcidin, IL-6, or BMP6, and six other iron-regulatory genes were determined using the Nanostring nCounter system. The area of blue on each section was digitally evaluated to measure the extent of Prussian blue staining objectively. Parameters were compared between HCC and non-HCC tissue and between microcytic and normocytic groups.Results: Hepcidin was decreased, and transferrin receptor 1 (TfR1) was increased in HCC tissue compared with non-HCC tissue. Non-HCC hepcidin RNA counts correlated negatively with MCV and positively with the extent of iron staining. Hepcidin expression was higher in non-HCC tissue of microcytic cases than in normocytic cases.Conclusions: Canine HCC cases showed relatively increased iron staining in non-HCC tissue and decreased hepcidin RNA in HCC tissue. Microcytic cases had higher hepcidin RNA in non-HCC tissue than normocytic cases. Future studies may extend these findings to protein quantification, cellular localization of RNA changes, and determining if iron loading in canine liver is a predisposing factor for HCC.

Leading the pack: Best practices in comparative canine cancer genomics to inform human oncology

“…More recently, high intensity focused ultrasound (HIFU) was used to treat pet dogs with solid tumours and nCounter analysis of biopsy samples demonstrated differential expression of 28 genes associated with T‐cell activation following treatment 103 . Several other groups have published gene expression data generated from canine samples using the nCounter platform, and a multitude of studies are ongoing using this tool as part of the PRECINCT consortium 104–106 . It is worth noting that custom panels can be designed to facilitate targeted interrogation.…”

“…103 Several other groups have published gene expression data generated from canine samples using the nCounter platform, and a multitude of studies are ongoing using this tool as part of the PRECINCT consortium. [104][105][106] It is worth noting that custom panels can be designed to facilitate targeted interrogation. This approach was recently employed to support validation of an antibody panel designed to distinguish lymphoid versus myeloid lineage leukaemias, demonstrating 100% concordance between flow cytometry and gene expression for the lymphoid leukaemias and 80% concordance for myeloid leukaemias.…”