[Establishment of human colon cancer transplantation tumor model in normal immune mice]

Objective: Establishment of a new model of human primary colon cancer transplantation tumor in normal immune mice and to provide a reliable experimental animal model for studying the pathogenesis of colon cancer under normal immunity. Methods: Human colon cancer cells come from colon cancer patients who underwent surgery in the Affiliated Hospital of Jining Medical College in 2017. The mice in the cell control group were inoculated with phosphate buffered solution (PBS) containing colon cancer cells, the microcarrier control group was inoculated with PBS containing microcarrier 6, and the cell-microcarrier complex group was inoculated with the PBS containing colon cancer cell-microcarrier complex. The cells of each group were inoculated under the skin of the right axilla of mice by subcutaneous injection, and the time, size, tumor formation rate and pathological changes under microscope were recorded. The transplanted tumor tissue was immunohistochemically stained with the EnVisiion two-step method, and the tumor formation rate of the transplanted tumor was judged according to the proportion of positive cells in the visual field. The polymerase chain reaction (PCR) method was used to detect the expression of human-specific Alu sequence in mice tumor tissue. Results: After inoculation with tumor cells, the mice in the cell control group and the microcarrier control group did not die and did not form tumors; the mice in the cell-microcarrier complex group had palpable subcutaneous tumors in the right axillary subcutaneously on the 5th to 7th days after inoculation, and tumor formation rate is 67% (10/15), and the tumor volume can reach about 500 mm(3) 2 to 3 weeks after vaccination. The immunohistochemistry results showed that CK20, CDX-2 and carcinoembryonic antigen were all positively expressed. The PCR results showed that the expression of human-specific Alu sequence can be detected in the transplanted tumor tissue of tumor-bearing mice. Conclusion: Human primary colon cancer cells used microcarrier 6 as a carrier to form tumors in normal immunized mice, and successfully established a new model of human colon cancer transplantation tumor in normal immune mice.