Deregulated expression of hnRNP A/B proteins in human non-small cell lung cancer: parallel assessment of protein and mRNA levels in paired tumour/non-tumour tissues

<p>Abstract</p> <p>Background</p> <p>Heterogeneous nuclear ribonucleoproteins (hnRNPs) of the A/B type (hnRNP A1, A2/B1, A3) are highly related multifunctional proteins participating in alternative splicing by antagonising other splicing factors, notably ASF/SF2. The altered expression pattern of hnRNP A2/B1 and/or splicing variant B1 alone in human lung cancer and their potential to serve as molecular markers for early diagnosis remain issues of intense investigation. The main objective of the present study was to use paired tumour/non-tumour biopsies from patients with non-small cell lung cancer (NSCLC) to investigate the expression profiles of hnRNP A1, A2/B1 and A3 in conjunction with ASF/SF2.</p> <p>Methods</p> <p>We combined western blotting of tissue homogenates with immunohistochemical examination of fixed tissue sections and quantification of mRNA expression levels in tumour versus adjacent normal-looking areas of the lung in the same patient.</p> <p>Results</p> <p>Our study, in addition to clear evidence of mostly uncoupled deregulation of hnRNPs A/B, has revealed hnRNP A1 to be the most deregulated protein with a high frequency of over-expression (76%), followed by A3 (52%) and A2/B1 (43%). Moreover, direct comparison of protein/mRNA levels showed a lack of correlation in the case of hnRNP A1 (as well as of ASF/SF2), but not of A2/B1, suggesting that different mechanisms underlie their deregulation.</p> <p>Conclusion</p> <p>Our results provide strong evidence for the up-regulation of hnRNP A/B in NSCLC, and they support the existence of distinct mechanisms responsible for their deregulated expression.</p

Regulatory cells in transplantation.

Regulatory T cells can play an important role in both the induction and maintenance of tolerance to donor alloantigens in vivo. Regulatory activity specific for donor alloantingens is enriched amongst CD4+CD25+ T cells in some settings and can be induced by manipulating the immune system before transplantation. Donor alloantigen-specific CD4+CD25+ regulatory T cells can control aggressive CD4+ as well as CD8+ T cells thereby preventing rejection and can mediate linked unresponsiveness. In vivo, donor alloantigen specific CD4+CD25+ cells are dependent on interleukin (IL)10 and CTLA4 for functional activity. These populations of regulatory cells induced by manipulating the adult immune system therefore have properties in common with naturally occurring regulatory T cells. The active regulation/suppression of immune responsiveness to donor alloantigens offers a way to silence aggressive immune responses directed to donor alloantigens thereby preventing damage to the graft from being inflicted. The generation of regulatory T cells with defined alloantigen specificity could provide dynamic control of rejection responses and offers a potential route to permanent graft survival without the need for life-long non-specific immunosuppression