Recently, the work from Dr. Haifan Lin’s group (Lab of Stem Cell Biology, SIAIS, ShanghaiTech University), titled “The Role of PIWIL4, an Argonaute Family Protein, in Breast Cancer”, was published in Journal of Biological Chemistry (doi: 10.1074/jbc.M116.723239).
PIWI proteins bind to PIWI-interacting RNAs (piRNAs) and play key roles in the biogenesis and functions of piRNAs. It has been reported that PIWI proteins are essential for stem cell self-renewal and germline development in diverse organisms, and are ectopically expressed in multiple forms of cancer. However, the role of PIWI in cancer remains elusive. Here we report that one of the four PIWI proteins in humans, PIWIL4, is highly expressed in both breast cancer tissues and the cytoplasm of MDA-MB-231 cell line derived from breast cancer. Reducing PIWIL4 expression drastically impairs migration ability of MDA-MB-231 cell, significantly increases their apoptosis apotosis, and mildly affects their proliferation. Our transcriptome and proteome analysis reveal that these functions are at least partially achieved via the PIWIL4 regualtion of TGF-β and FGF signaling pathways and major histocompatibility complex (MHC) class II proteins. These findings suggest that PIWIL4 may serving as a potential therapeutic target for breast cancer.
A proposed regulation mechanism of PIWIL4 in breast cancer cell line MDA-MB-231