One of the apoptotic resistance mechanisms in breast cancer stem cells (CSCs) is designed by the existence of tumorassociated macrophages (TAMs), type 2 macrophages. TAMs enhance the apoptotic resistance of CSCs by extremely decreasing low levels of inducible nitric oxide (iNO) and a reactive oxygen intermediate (ROI). On the other hand, heat shock protein-70 (Hsp-70) expression may modulate TAMs to upregulate those molecules. Typhonium flagelliforme (TF) tuber extract has an apoptotic activity through increasing iNO and ROI levels of cancer cells. However, the role of TF in increasing the Hsp-70 expression of TAMs leading to apoptosis improvement remains unclear. TAMs were produced by coculturing the human breast cancer-derived peripheral blood mononuclear cells with the CSCs. TAMs were assigned into two treatment groups consisting of one treatment group (treated by TF at 50.89 μg/ml) and the control group (medium administration only). The expression of Hsp-70 was analyzed by immunocytochemistry. This study found that Hsp-70 expression was shown to be significantly increased in TAMs. In conclusion, TF may promote the increase of Hsp-70 expression in TAMs. Hsp-70 as a promising drug target in cancer therapy for reducing resistance to cancer therapy has the potential to be developed and investigated further.
Key words: apoptosis resistance, CSCs, Hsp70, TAM, Typhonium flagelliforme.
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