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

Background: 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. Objectives: 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. Methods: 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. Results: 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). Conclusion: 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.