Expression and secretion of the pro­inflammatory cytokine IL­8 is increased in colorectal cancer cells following the knockdown of non­erythroid spectrin αII.

Non­erythroid spectrin αII (SPTAN1) expression is decreased in ~40% of cases of MLH1­deficient colorectal cancer (CRC). SPTAN1 knockdown reduces cell viability, cellular mobility and cell­cell contact formation, indicating that the SPTAN1 plays an important role in tumour growth, attachment and in regulating the tumour microenvironment. Changes in the tumour microenvironment can affect the immune response. Therefore, in the present study, proteome arrays were used to analyse the expression of 119 different chemokines and soluble receptors in CRC cell lines in which mutL homologue 1 (MLH1) or SPTAN1 were knocked down. The levels of interleukin (IL)­8 were significantly increased in the cells in which SPTAN1 was knocked down, both at the mRNA and protein level. ELISA demonstrated that the cells in which SPTAN1 was knocked down secreted increased quantities of IL­8, and chemotaxis assays revealed the enhanced trafficking of neutrophils, which was induced by media containing higher levels of IL­8. The IL­8 receptors, CRCX1 and CRCX2, were expressed in all the cell lines examined; however, their expression was not directly associated with IL­8 expression. The results of the present study thus demonstrated that CRC cells in which SPTAN1 was knocked down secreted significantly higher levels of IL­8, which in­turn increased the migration of neutrophilic granulocytes. As MLH1­deficient CRC exhibits an increased infiltration of cytotoxic T­cells and is associated with a decreased SPTAN1 expression, it can thus be hypothesized that CRC with a low SPTAN1 expression may release increased quantities of IL­8, resulting in increased immune cell infiltration.

Rejection quantity in kidney transplant recipients is associated with increasing intracellular interleukin-2 in CD8+ T-cells.

BACKGROUND: CD8+ T-cells and interleukin-2 play an important role during organ rejection in kidney transplant recipients. Numerous studies showed increased interleukin-2 levels during acute rejection. The aim of our study is to show an association between intracellular interleukin-2 in CD8+ T-cells and the incidence of those who underwent organ rejection in kidney transplant recipients. METHODS: 407 transplant recipients were included into this study. The rejection incidence was investigated from the patient records. White blood cells from recipients were separated using a ficoll gradient. The cells were double-gated (CD3+ and CD8+) for the analysis of cellular percentage for intracellular interleukin-2 with a flow cytometer. RESULTS: The percentage of CD8+ cells with detectable intracellular interleukin-2 was significantly higher in renal transplant recipients with a documented rejection compared to recipients without any history of rejection (9.06±0.50, N=133 vs. 4.28±0.24, N=274, p<0.0001, t-test). Further, there was a significant increase in patients with one (8.02±0.54, N=80, p<0.0001, t-test), two (10.40±1.17, N=33, p<0.0001, t-test) or three (11.82±1.58, N=18, p<0.0001, t-test) rejection events. CONCLUSIONS: Past studies showed, that during acute organ rejection intracellular interleukin-2 is increased in cytotoxic T-cells, supposed to be a marker for this event. We were able to show, that intracellular interleukin-2 in CD8+ T-cells is also increased after organ rejection. Furthermore it seems to depend on the quantity of rejection events. Further studies in recipients with increased intracellular interleukin-2 in cytotoxic CD8+ T-cells and documented history of organ rejection are needed to identify this as a possible risk factor for further rejection events.