Enhanced Expression of Interferon-γ-Induced Antigen-Processing Machinery Components in a Spontaneously Occurring Cancer

AbstractIn human tumors, changes in the surface expression and/or function of major histocompatibility complex (MHC) class I antigens are frequently found and may provide malignant cells with a mechanism to escape control of the immune system. This altered human lymphocyte antigen (HLA) class I phenotype can be caused by either structural alterations or dysregulation of genes encoding subunits of HLA class I antigens and/or components of the MHC class I antigen-processing machinery (APM). Herein we analyze the expression of several proteins involved in the generation of MHC class I epitopes in feline injection site sarcoma, a spontaneously occurring tumor in cats that is an informative model for the study of tumor biology in other species, including humans. Eighteen surgically removed primary fibrosarcoma lesions were analyzed, and an enhanced expression of two catalytic subunits of immunoproteasomes, PA28 and leucine aminopeptidase, was found in tumors compared to matched normal tissues. As a functional counterpart of these changes in protein levels, proteasomal activities were increased in tissue extracts from fibrosarcomas. Taken together, these results suggest that alterations in the APM system may account for reduced processing of selected tumor antigens and may potentially provide neoplastic fibroblasts with a mechanism for escape from T-cell recognition and destruction

Effects of Two Concentrations of a Clinical Propofol Formulation on Canine Mammary Tumor Cells NET1 Gene Expression: A Preliminary Evaluation of Possible Anti-Metastatic Properties

Background: Several studies show that anesthesia for primary cancer surgery might influence cancer recurrence regulating specific gene expression like the Neuroepithelial transforming (NET) 1 protein. This gene has been associated with malignant behaviors and represents a novel prognostic marker in human epithelial cancers. The present study investigates the in vitro effects of a clinically available propofol formulation on NET1 expression in canine mammary tumor cells, as a potential translational model. Methods: Two canine mammary tumor cell lines, primary (CIPp) and metastatic (CIPm), were incubated with propofol (1-10 μg ml-1). Cells were lysate and RNA isolated at pre-established time points. A quantitative PCR was performed to evaluate NET1 gene expression and resulting delta cycle thresholds compared. Results: Baseline NET1 gene expression was lower in CIPm compared with CIPp. Both propofol concentrations increased NET1 mRNA levels in CIPp after 6 hours. In CIPm the higher propofol concentration caused a reduction in gene expression after 6 hours. Propofol decreased gene expression in both cell lines and only in CIPp after 12 and 24 hours, respectively. No differences were found in CIPm after 48 hours. The higher concentration of propofol increased gene expression in CIPp after 48 hours. Conclusions: Metastatic cells showed a lower basal NET1 expression and were less responsive to treatments compared to primary tumor cells. Propofol effectively influenced NET1 gene expression without a clear dose dependency. Most treatment time-points showed a decreased NET1 gene expression, although increases were also observed. Keywords: Anesthesia cancer; canine mammary tumor; NET1 gene; propofol.Peer reviewe

Canine mammary tumour cells exposure to sevoflurane : effects on cell proliferation and neuroepithelial transforming gene 1 expression

Objective The influence of perioperative factors, such as anaesthetic and analgesic techniques, on metastatic spread following surgery for primary cancer removal is of growing interest. The present study investigated the effects of sevoflurane on canine mammary tumour cell proliferation (MTT colorimetric assay) and on the expression of neuroepithelial transforming gene 1 (NET1). Study design Prospective controlled in vitro trial. Study material Primary (CIPp) and metastatic canine tubular adenocarcinoma (CIPm) cells. Methods To perform MTT tests, cell lines were seeded at a density of 3000 cells per well and incubated with sevoflurane (1, 2.5 or 4 mM) or only with the culture medium (control). Sevoflurane was added to the cell cultures every hour to avoid changes in drug concentration. MTT assays were performed after 6 hours of exposure obtaining absolute values of absorbance. The RNA isolated from the lysates of the same cell lines underwent quantitative polymerase chain reaction to evaluate NET1 gene expression changes compared with controls. One-or two-way analysis of variance was used as appropriate (p <0.05). Results A significant increase in cell proliferation compared with controls was observed in CIPp treated with lower sevoflurane concentrations, whereas a significant decrease in cell proliferation was found in CIPm treated with all the sevoflurane concentrations. All CIPp treatments did not induce changes in gene expression compared with controls, whereas a significant increase in gene expression was observed in CIPm between controls and the higher sevoflurane concentration. Conclusions and clinical relevance Sevoflurane treatments modified the cell proliferation rate in both cell lines showing an increase or decrease when applied to CIPp or CIPm, respectively. Expression of the NET1 gene increased after treatment with sevoflurane 4 mM in metastatic cells. The role of sevoflurane on cancer recurrence should be further investigated.Peer reviewe