Charlène Vigouroux1, Jean-Matthieu Casse2, Shyue-Fang Battaglia-Hsu3, Lydia Brochin1, Amandine Luc4, Christophe Paris5, Stéphanie Lacomme6, Jean-Louis Gueant3, Jean-Michel Vignaud7, Guillaume Gauchotte8. 1. Department of Pathology, CHU Nancy, France. 2. Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France. 3. INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France; Department of Molecular Biology and Biochemistry, CHU Nancy, France. 4. INGRES, EA7298, Faculty of Medicine, Université de Lorraine, Nancy, France. 5. INGRES, EA7298, Faculty of Medicine, Université de Lorraine, Nancy, France; Department of Occupational Diseases, CHU Nancy, France. 6. Centre de Ressources Biologiques, BB-0033-00035, CHU Nancy, France. 7. Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France; Centre de Ressources Biologiques, BB-0033-00035, CHU Nancy, France. 8. Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France. Electronic address: g.gauchotte@chu-nancy.fr.
Abstract
OBJECTIVES: In non small cell lung carcinoma (NSCLC), earlier studies supported a prognostic value of intra-cytoplasmic HuR expression. HuR is a RNA binding protein previously shown to stimulate proliferation, but the link between HuR and proliferation in NSCLC has not yet been evaluated. The first objective of this study was to analyze the expression of HuR in a series of NSCLC and to correlate this to two proliferation markers, Ki-67 and MCM6. As potential post-transcriptional regulatory mechanisms for HuR expression, two miRNAs, miR16 and miR519, were also analyzed. Finally, because HuR methylation could be involved in its nucleocytoplasmic shuttling, the expression of methyl(R217)HuR and its relation to cancer survival were determined. MATERIALS AND METHODS: Immunohistochemistry was used to evaluate the expression of HuR, methy(R217)HuR, Ki-67 and MCM6 in a series of 190 NSCLCs. The level of miR16 and miR519 was determined by qRT-PCR. RESULTS: Higher cytoplasmic HuR staining was found in tumor vs. control paired normal lung (p<0.0001), but without correlation with survival. The level of methyl(R217)HuR was correlated both significantly with intra-cytoplasmic HuR staining (p<0.001), and overall survival (p=0.01). MCM6 correlated to a poorer overall survival (p<0.01). Both MCM6 and Ki-67 were positively correlated with HuR nuclear staining (p<0.0001 and p<0.001, respectively). On the contrary, MCM6 and Ki-67 correlated inversely to methyl(R217)HuR (p<0.001 and p=0.01, respectively). The levels of miR16 and miR519 were significantly lower in tumor tissue vs. paired normal lung (p<0.0001), but only miR519 correlated inversely to HuR expression (p=0.01). CONCLUSION: While overall cytoplasmic HuR level was higher in tumor tissues, we found unexpectedly that methyl(R217)HuR was a marker of good prognosis. Furthermore, our data suggest that HuR level could be regulated by miR519. Finally, we demonstrated that Ki-67 and MCM6, both correlated with HuR, are valuable markers of poor prognosis in NSCLC.
OBJECTIVES: In non small cell lung carcinoma (NSCLC), earlier studies supported a prognostic value of intra-cytoplasmic HuR expression. HuR is a RNA binding protein previously shown to stimulate proliferation, but the link between HuR and proliferation in NSCLC has not yet been evaluated. The first objective of this study was to analyze the expression of HuR in a series of NSCLC and to correlate this to two proliferation markers, Ki-67 and MCM6. As potential post-transcriptional regulatory mechanisms for HuR expression, two miRNAs, miR16 and miR519, were also analyzed. Finally, because HuR methylation could be involved in its nucleocytoplasmic shuttling, the expression of methyl(R217)HuR and its relation to cancer survival were determined. MATERIALS AND METHODS: Immunohistochemistry was used to evaluate the expression of HuR, methy(R217)HuR, Ki-67 and MCM6 in a series of 190 NSCLCs. The level of miR16 and miR519 was determined by qRT-PCR. RESULTS: Higher cytoplasmic HuR staining was found in tumor vs. control paired normal lung (p<0.0001), but without correlation with survival. The level of methyl(R217)HuR was correlated both significantly with intra-cytoplasmic HuR staining (p<0.001), and overall survival (p=0.01). MCM6 correlated to a poorer overall survival (p<0.01). Both MCM6 and Ki-67 were positively correlated with HuR nuclear staining (p<0.0001 and p<0.001, respectively). On the contrary, MCM6 and Ki-67 correlated inversely to methyl(R217)HuR (p<0.001 and p=0.01, respectively). The levels of miR16 and miR519 were significantly lower in tumor tissue vs. paired normal lung (p<0.0001), but only miR519 correlated inversely to HuR expression (p=0.01). CONCLUSION: While overall cytoplasmic HuR level was higher in tumor tissues, we found unexpectedly that methyl(R217)HuR was a marker of good prognosis. Furthermore, our data suggest that HuR level could be regulated by miR519. Finally, we demonstrated that Ki-67 and MCM6, both correlated with HuR, are valuable markers of poor prognosis in NSCLC.