CD44+ cancer cell-induced metastasis: A feasible neck metastasis model.

Neck metastasis of oral squamous cell carcinoma (OSCC) indicates a poor prognosis. Few neck metastasis models are currently available for drug trials and clinical research on OSCC. This study constructed a feasible animal model of neck metastasis by using CD44+ stem cell-like cancer cells. Real-time PCR was used to determine the expression levels of several reported cancer stem cell (CSC) markers, including CD44, CD133, ALDH1 and OCT4, in three OSCC cell lines. Magnetic sorting and DiO/DiD labelling were used to isolate subpopulations of cells and monitor cancer cell migration. Sorted and labelled CSC-like cells were injected into the tongue of nude mice. Tumour and metastatic lymph nodes were histologically examined through immunostaining and tracer staining. High rate of metastasis was observed in neck lymph nodes in CD44+ group. This phenomenon was confirmed in clinical OSCC patients, and CD44 expression levels were higher in tumours with lymph node metastasis than in carcinomas in situ. Therefore, we have successfully constructed a neck metastasis model by using CD44+ CSCs. This model can form tumour and show metastases within a short period of time compared with other models; additionally, this model may be used in short-term pharmacological experiments involving animals and in basic clinical studies.