Importantly, mammalian DDX5 and DDX17 are involved in cancer progression when overexpressed through alteration of transcription and signaling pathways, meaning that they are possible targets for cancer therapy.
In terms of the deregulated expression of p68 in breast cancer and the high prevalence of this cancer among women, it can be informative to review the precise function of this factor in the breast cancer.
Recently it has been reported that tyrosyl-phosphorylation of p68 promotes β-catenin nuclear translocation and cancer metastasis through elevating the epithelial-mesenchymal transition.
Nuclear accumulation of β-catenin is important for cancer development and it is found to overlap with p68 (DDX5) immunoreactivity in most breast cancers, as indicated by both clinical investigations and studies in cell lines.
p68 (DDX5) acts both as an ATP-dependent RNA helicase and as a transcriptional co-activator of several cancer-associated transcription factors, including the p53 tumor suppressor. p68 is aberrantly expressed in a high proportion of cancers, but the oncogenic drive for, or the consequences of, these expression changes remain unclear.
Here we show that the mutant p68 peptide has an exceptionally high affinity to the presenting MHC class I molecule K(b) and that spleen cells from immunized young syngeneic mice adoptively transferred to Rag(-/-) or cancer-suppressed euthymic mice eradicate 8101 tumors larger than 1 cm in average diameter and established for several weeks.
In the present study, we examined the phosphorylation status of p68 in six different cancer cell lines and compared the results with those in cells derived from the corresponding normal tissues.