Paclitaxel resistance and nucleostemin upregulation in metastatic mouse breast cancer cells

BACKGROUND: In patients with metastatic breast cancer, paclitaxel is the first-line chemotherapeutic treatment. In these cases, paclitaxel resistance is a fatal side effect. Nucleostemin (NS) is involved in the proliferation of some stem cells and cancer cells, but no studies have been done to examine the relationship between nucleostemin, metastasis, and chemoresistance in breast cancer. METHODS: After generating an animal model of breast cancer, primary and metastatic tumor cells were isolated, multiplied, and called 4T1T, 4T1L, and 4T1B from the tumor mass, lung, and brain of cancerous mice respectively. The expression of NS in 4T1T, 4T1L, and 4T1B was examined using real-time polymerase chain reaction. By using MTT assays, the cytotoxic effect of paclitaxel on these cells was evaluated. RESULTS: Our findings revealed that metastatic tumor cells significantly increased their NS expression. When compared to primary tumor cells, NS was up-regulated 6-fold and 23-fold in 4T1L and 4T1B, respectively. Simultaneously, our findings also show that 4T1L and 4T1B are more resistant to the cytotoxic effects of paclitaxel than 4T1T. CONCLUSIONS: For the first time, these findings provided important insights into the NS expression in the metastatic cascade of breast cancer. The analysis of the molecular properties of metastatic tumor cells can be used to obtain a greater understanding of the molecular and genetic aspects of chemoresistance and to also design targeted therapeutic strategies to combat breast cancer metastasis. (Cite this article as: Rezapour N, Kamalabadi-Farahani M, Atashi A, Zarrinpour V. Paclitaxel resistance and nucleostemin upregulation in metastatic mouse breast cancer cells. Minerva Biotechnol Biomol Res 2023;35:16-21. DOI: 10.23736/S2724-542X.23.02945-0)