Taken together, in the light of all the observations, we suggest
that RBM5 could be a promising candidate towards lung cancer clinical management in terms of the metastatic status. Nevertheless, the detailed molecular mechanism involved in RBM5-mediated metastasis needs to be further investigated. Our data also showed an inverse correlation between RBM5 expression and EGFR and KRAS expression in NSCLC. Alteration of EGFR expression and gene amplification has been reported as between 7 % and 45 % in lung cancer selleck cases [28–30], which may also be due to variations in techniques, criteria to determine positivity, and inter-observer variability [29, 30]. In our study, overexpression of EGFR was found in 33 % of specimens of NSCLC, with a somewhat higher incidence in ACs than in SCCs. Moreover, overexpression
of KRAS was found in 45 % of specimens of NSCLC, with a somewhat higher incidence in SCCs than in ACs. Overexpression of EGFR and KRAS proteins was associated with lymph node metastasis and with a more advanced pathologic stage. Our current study for the first time demonstrated www.selleckchem.com/products/pf299804.html a correlation between the expression levels of RBM5, EGFR and KRAS in NSCLC tissues, with the data suggesting that disruption of RBM5 apoptosis-induced activity and tumor suppressor Ruxolitinib molecular weight function is consistent with the potent oncogenic activity associated with EGFR and KRAS overexpression. The differential expression of these three genes in NSCLC suggests the presence of Depsipeptide order a complex regulatory network involving tumor suppression and oncogenic expression. Details of the inverse relationship between RBM5, EGFR and KRAS are only beginning to be delineated [19, 31]. For instance, HER2 overexpression was shown to affect the alternative splicing of RBM5. One cytotoxic isoform, RBM5 + 5 + 6 t, was downregulated in breast cancer cells (both primary tumors and a cell line) that have overexpressed HER2
, which suggested that factors in the EGFR pathway may function as upstream modulators of RBM5 function and/or expression. In order to investigate this hypothesis, we downregulated EGFR in NCI-H1975 lung adenocarcinoma cells that have activated EGFR, using small interfering RNA, and analyzed RBM5 expression [CMJ, submitted]. The results of this study demonstrated that downregulation of activated EGFR, in the NCI-H1975 lung cancer cell line, did not, in fact, correlate with upregulation of RBM5, suggesting that RBM5 functions upstream of EGFR. That deletion of the region encompassing the RBM5 gene is one of the earliest lesions associated with smoking does suggest that downregulation of RBM5 is necessary for cancer initiation events.