Research Projects

Triple-negative breast cancer (TNBC) is a highly heterogeneous disease, and its treatment is particularly challenging due to the absence of receptors for estrogen, progesterone, and human epidermal growth factor. Paclitaxel (PTX) is a commonly used frontline chemotherapeutic drug for the treatment of advanced TNBC, either alone or in combination with other therapies. However, resistance to PTX is a major obstacle to successful TNBC treatment. PTX-resistant TNBC cells develop resistance through various mechanisms, including inducing stemness, recruiting tumor-associated macrophages (TAMs), and inducing the expression of ABC family proteins by activating the Yes-associated protein (YAP) signaling pathway. Furthermore, CD151 mediates the recruitment and bidirectional interactions of stem cells and TAMs. To overcome this resistance, a combination of verteporfin (VP) and 2-thio-6-azauridine (TAU) has been proposed, and their potential synergistic effects are being investigated. VP has been reported to inhibit YAP and has broad clinical application prospects in various cancers, including breast cancer. Targeting CD151 using TAU sensitizes PTX-resistant TNBC cells by targeting ABC transporters. Additionally, a combination of VP and TAU has been shown to induce toxicity in PTX-resistant TNBC stem cells and inhibit the proliferation of tumor cell-induced TAMs. Based on these findings, the CD151/YAP axis may contribute to PTX resistance by promoting stemness, activating ABC family members and polarizing TAMs. Therefore, targeting YAP and CD151 with the combinatorial treatment of VP and TAU sensitizes PTX-resistant TNBC stem cells. The objectives of this study are to evaluate the combinatorial effect of VP and TAU on the growth and self-renewal of PTX-resistant TNBC stem cells, the interplay of PTX-resistant TNBC stem cells and TAMs, and the growth of PTX-resistant TNBC stem cells in nude mice. The main experimental strategies include examining the combinatorial effect of VP and TAU on sensitization of PTX-resistant MDA-MB 231 cells and patient-derived PTX-resistant TNBC stem cells using BrdU incorporation, γ-H2AX, flow cytometry, and TUNEL assays. The self-renewal capacity and differentiation of cells will be assessed using a mammosphere formation assay, as well as examining the expression of CD44, CD24, ALDH1, SOX2, OCT4, and NANOG by flow cytometry, immunofluorescence, and western blot analysis, and cytokine secretion by cytokine profiling. The combinatorial effect of VP and TAU on the expression of CD163 and CD206 by flow cytometry, STAT3, and PD-1 by western blot analysis in PTX-resistant TNBC stem cell-induced TAMs will be investigated using a coculture model. Finally, tumor growth will be assessed in a nude mouse model, and the VP and TAU present in plasma samples of mice will be analyzed by LC-MS/MS. Overall, this study suggests that the combination of VP and TAU could be an effective treatment for paclitaxel-resistant TNBC.