Overexpression of Argonaute HIWI Gene in Colorectal Cancer Stem Cells and Colorectal Cancerous Tissue

Recent studies have demonstrated that Hiwi has a crucial role in stem cell self-renewal in various organisms, and it is associated with some cancers.

In the present study, Hiwi expression was examined in different grades of primary human colorectal cancer (CRC), colorectal cancer stem cells (CRCSCs), and HT-29 CRC cell line.

The CRC tissue samples were collected from 20 patients with CRC. Furthermore, the HT-29 cell line, CRCSC, and 13 normal colorectal tissue samples were prepared. The expression of Hiwi at mRNA and protein levels was determined by real-time polymerase chain reaction (Real-time PCR), flow cytometry, Western blot, and immunohistochemistry.

The overexpression of Hiwi was detected in 40% (3.351±2.94, P<0.05) of clinical CRC tissue specimens. We also observed a significant increase in the expression of Hiwi in CRCSCs (5.94±0.05, P<0.005). Hiwi expression was significantly higher in CRCSC compared to that in the colorectal cancer tissue and HT-29 cells (P<0.01). Hiwi mRNA level was significantly correlated to tumor grade (P< 0.01) and stage (P< 0.01).

As evidenced by the obtained results, Hiwi can be considered an oncogene in progressive cancer and, therefore, can be a valuable biomarker and target in therapeutic procedures.