RNAi-mediated Silencing of LY6K Expression Suppresses the Growth of EpCAM+ CD44+ HCT116 Human Colon Cancer Stem Cells In Vitro and In Vivo

Introduction: Colorectal cancer (CRC) is a leading cause of cancer-related mortality, with poor survival outcomes due to therapy-resistant cancer stem cells (CSCs). CSCs contribute to tumor initiation, progression, and recurrence. Lymphocyte antigen 6 complex, locus K (LY6K), a member of the Ly6/uPAR family, is highly expressed in various human cancers and associated with poor prognosis, but its role in CRC remains unclear. This study investigates the function of LY6K in colorectal CSCs (CCSCs) and its therapeutic potential.

Methods: EpCAM⁺ CD44⁺ CCSCs were isolated from HCT116 cells, and the expression of LY6K was analyzed by qPCR and Western blot. RNA interference was used to silence LY6K to evaluate its potential role of LY6K on the proliferation, migration and invasion, and cell cycle of CCSCs using MTS assays, Transwell migration and invasion assays, flow cytometric analyses, respectively. In vivo, CCSCs were implanted into BALB/c nude mice, and tumor growth and survival were assessed following siLY6K treatment.

Results: LY6K expression was elevated in CCSCs. siLY6K-mediated silencing in CCSCs inhibited cell proliferation by inducing G1 phase cell cycle arrest and suppressed migration and invasion. LY6K silencing significantly reduced tumor growth and extended survival in a mouse model.

Conclusion: LY6K is a critical regulator of CCSC proliferation and invasion. Its silencing suppresses tumor growth and extended survival in a CRC colorectal cancer xenograft model. These findings suggest that targeting LY6K may be a promising therapeutic strategy to reduce tumor metastasis and therapy resistance in colorectal cancer.