Sir,
We are grateful for the feedback regarding our article ‘Strong reduction of AGO2 expression in melanoma and cellular consequences' (Völler et al, 2013b). In this study, we discovered a melanoma-specific modulation of AGO2, a member of the miRNA-processing cascade. Moreover, we demonstrated that AGO2 reduction is a direct trigger for the deregulated miRNA pattern in melanoma.
The reduced AGO2 protein amount was observed in melanoma cell lines as well as tissue samples of primary tumours and metastasis. Interestingly, AGO2 reduction was not detectable at mRNA expression level, which indicates a further processing of the AGO2 mRNA transcript in melanoma.
Previous studies analysing the enzymes of the miRNA-processing cascade in cancer were either focused on the mRNA level (e.g., Sand et al, 2012; Jafari et al, 2013) or did not connect the deregulation with a disordered miRNA pattern (e.g., Ma et al, 2011; Grund et al, 2012; Jafarnejad et al, 2013; Völler et al, 2013a). Therefore, we stated that ‘Deregulation of miRNA expression was observed in several types of cancer, but changes in the miRNA-processing enzymes have not been analyzed until today'. However, this statement would have to be focused on the enzyme AGO2 and analysis on protein level in melanoma. We apologize that the current statement is too general as the authors of the previous comment correctly stated.
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