[The cultivation and identification of lacrimal gland adenoid cystic cancer stem cells].

OBJECTIVE: To isolate and cultivate the Lacrimal gland Adenoid Cystic Carcinoma cells line, study Cancer Stem Cells properties. METHOD: Experimental study. Lacrimal gland adenoid cystic carcinoma cancer stem cells were cultivated in serum-free suspension culture and the morphological changes were observed. Cells were divided into two groups, the LACC-CSC experimental group and the LACC control group. The flow cytometry instrument was used to detect the expression of classical stem cell markers CD133 and ABCG2. Transwell chamber was used to detect the cancer stem cell aggressivity and differentiated into the vascular endothelial cells. The tumorigenic force in vitro xenotransplantation were applied. RESULT: LACC cells can grow suspensively after vaccinated in serum free medium and form tumor microspheres after 10-12 days. Flow cytometry experiments showed that the expression ratio of stem cell markers CD133 in LACC-CSC was (35.67 ± 6.86)%, significantly different to LACC with (0.46 ± 0.48)%, (t = 8.867, P < 0.05). Similarly, the expression ratio of stem cell marker ABCG2 in LACC-CSC was (39.99 ± 4.54)%, significantly different to LACC with (6.75 ± 1.34)%, (t = -9.932, P < 0.05). In vitro experiment of Matrigel invasion, LACC-CSC went through the matrigel basement membrane averagely (32.60 ± 8.79)/HP contrary to LACC with average (10.20 ± 2.77)/HP after 24 hours, showing statistically significance (t = 5.433, P < 0.05) between the two groups. After training for 48 hours, the difference between two groups was still obvious (t = 5.779, P < 0.05) with LACC-CSC average (62.60 ± 4.83)/HP to LACC (44.00 ± 5.34)/HP. When induced by serum medium containing VEGF and bFGF, LACC-CSC grew adherent gradually and cell morphological changes occurred after continuous induction to long spindle cells. When cultured into three-dimensional matrix structure they formed vessel samples and expressed vascular endothelial marker CD31 and CD34. Transplanted tumor in vitro experiment, mice of LACC-CSC group grew tumors in 9 days with 100% tumorigenic rate, whereas LACC group 12 days with 100% tumorigenic rate. CONCLUSIONS: LACC-CSC can be obtained through serum-free culture method. LACC-CSC grew suspensively and expressed classical stem cell markers. LACC-CSC were identified as cancer stem cells with stronger migration and invasion. LACC-CSC have tumorigenic force and multi-directional differentiation potential with general characteristics of the stem cell.

[Isolation and identification of cancer stem cells from human LACC cell line].

OBJECTIVE: To find ways to isolate and culture lacrimal adenoid cystic carcinoma (LACC) stem cells from human LACC cell line and to identify their biological properties. METHODS: Experimental research. LACC cells were digested, centrifuged and suspended in specific serum free medium (SFM) to get LACC cancer stem cell spheres. Limiting dilution analysis and monoclonal formation assay were performed to determine the proportion of cancer stem cells in LACC cell line. MTT assay was used to determine the proliferation and chemotherapeutic drug resistance of stem cell spheres. The expressions of cell surface markers CD44⁺/CD24⁻ were detected by flow cytometry. Stem cell spheres differentiation were induced by dropping serum medium into SFM and the morphologic changes were observed. The IC50 and UV optical density of two kinds of cells were tested by Student's t-test. RESULTS: About (0.92 ± 0.02) % cells were clonogenic in LACC cell line. They could survive and proliferate to form free-floating cell spheres in SFM, which could stably passaged. The IC50 values of cancer stem cells and LACC cell line were 22.53 mg/L and 11.06 mg/L (t = 37.94, P < 0.05), which suggested that cancer stem cells were more resistant to cis-platinum than LACC cell line. In flow cytometry assay, 84.25% stem cell spheres were CD44⁺/CD24⁻ cells, comparing with 23.77% in LACC cell line. Stem cell spheres could differentiate into normal adenoid cystic carcinoma cells in medium with serum. CONCLUSION: LACC stem cell spheres, containing a large number of cancer stem cells, could be obtained by serum free suspension culture. This provide us an ideal model system for cancer stem cell research.