Effect of Tacrolimus in Triple Negative Breast Cancer Animal Model

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Aktaş S., Erçetin A. P., Kolatan H. E.

International Journal of Clinical and Experimental Medicine Research, cilt.5, sa.3, ss.269-277, 2021 (Hakemli Dergi)

Özet

Aim: Triple negative breast cancer has poor prognosis requiring new combination treatments strategies. Structurally resembling the best known mTOR inhibitor of rapamycin and a calcineurin inhibitor, tacrolimus modulates mTOR in the absence of rapamycin with antiproliferative efficacy shown for cancer types like glioblastoma multiforme, hepatocellular carcinoma, and lymphoma, the aim of this study is to assess the efficacy of tacrolimus on tumor cells from an in vitro 4T1 cell line representing triple-negative breast cancer and in a cancer model in experimental animals. Method: 4T1 triple-negative breast cancer cell line was incubated with tacrolimus (1, 10, 20, 30, 40, 50, 100 µm) for 24, 48 and 72 hours. Cell viability percentages were assessed with WST-1 analysis. 14 athymic nude mice with mean weight 25 g aged 5-7 weeks were injected with 4T1 cells subcutaneously. After 150 mm 3 tumor development, animals were randomized into a control group administered physiologic serum and an experimental group administered 10 mg/kg tacrolimus, on the 1st and 8th days via the intraperitoneal route. On the 14th day, animals were sacrificed and changes in tumor tissue were examined histopathologically and for apoptosis with flow cytometry with annexin-V and propidium iodide in fresh tissue suspension. Results: The LD50 dose of tacrolimus was identified as 30 µM. In the triple-negative breast cancer model in experimental animals, the targeted tumor size was reached in 8-12 days. Side effects were not observed from the two doses of tacrolimus administered at a one-week interval. After sacrifice on the 14th day, histopathologic assessment of tumor tissues observed prominent necrosis, necrobiosis and apoptosis in the tumor group compared to the control group. Annexin-V+PI flow cytometry investigation found the early apoptotic effect of tacrolimus was higher compared to late apoptosis and necrosis. Conclusion: Tacrolimus was found to be effective both in vitro and in vivo on triple-negative breast cancer triggering necrosis in addition to apoptosis. Tacrolimus is promising as a treatment choice for the clinical problem of triple-negative breast cancer.