B16 melanoma growth characteristic in C57BL/6 mice with various methods of obtaining tumor material and syngeneic tumor transplantation sites

Background. In non-clinical studies of antitumor agents, the use of various sources of tumor material and transplant sites significantly affects the growth parameters of syngeneic tumors, their invasive potential, and the profile of metastasis.

Aim. To evaluate the growth kinetics of syngeneic melanoma B16 in C57BL/6 mice after orthotopic (intradermally) and intramammary (into the mammary fat pad) transplantation of tumor material obtained by different methods.

Materials and methods. The experiment was carried out on mature C57BL/6 female mice. There were six groups with eight animals each. Groups 1–3 were transplanted with isografts of melanoma B16 (50 % cell suspension from tumor fragments), groups 4–6 were inoculated with cancer cells from primary culture, cultured in vitro to the early (P6) and late (P14) passages. Inoculation was performed intradermally or into the mammary fat pad.

Results. It was found that the method of obtaining tumor material (isograft or cell line), the number of in vitro passages and the site of transplantation (intradermally or intramammary) significantly affects the phenotypic features of melanoma B16 after inoculation with animals. As a result of clonal selection in vitro and in vivo, significant differences were observed in the time of appearance of the measured tumors, growth kinetics and metastasis profile. Intramammary tumor transplantation provided a reduction in the incidence of ulcers (tumor necrosis) compared with intradermal transplantation, regardless of the source of tumor material. At the same time, the development of tumor ulceration did not significantly affect the life span of animals.

Conclusion. The results of the study complement the existing data that B16 syngeneic melanoma cells have both hereditary and selective phenotypic characteristics that affect their ability to metastasize. Our data can be used in the routine work of preclinical centers for the purpose of planning and conducting studies using syngeneic tumor models.

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