Contribution of Mesenchymal-like and Epithelial Cellular Subsets to Chemotherapy Resistance in Triple-Negative Breast Cancer

Vuong, N. B.; korolkova, O. Y.; Izban, M.; SAKWE, N. I.; McIntosh, A. R.; Ball, D.; Black, P. J.; Edwards, A.; Ballard, B. R.; Adunyah, S. E.; Sakwe, A. M.

doi:10.1101/2025.11.01.685128

bioRxiv · 10.1101/2025.11.01.685128

Contribution of Mesenchymal-like and Epithelial Cellular Subsets to Chemotherapy Resistance in Triple-Negative Breast Cancer

Vuong, N. B.·korolkova, O. Y.·Izban, M.·SAKWE, N. I.·McIntosh, A. R.·Ball, D.·Black, P. J.·Edwards, A.·Ballard, B. R.·Adunyah, S. E.·Sakwe, A. M.

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Abstract

Background/ObjectivesTriple-negative breast cancer (TNBC) tumors are typically heterogeneous, predominantly epithelial tissues with discrete patches of mesenchymal-like TNBC cells, that differ in their invasiveness, proliferation potential and response to treatment. However, the contribution of mesenchymal-like and epithelial TNBC cells in the persistence of chemotherapy resistant disease remains poorly understood. MethodsMesenchymal-like and epithelial TNBC cell types were detected by multiplex fluorescent immunohistochemistry using antibodies against vimentin, Ki67, and Annexin A6 (AnxA6). Chemotherapy drug resistant mesenchymal-like and epithelial TNBC cell populations were established by pulse exposure and stepwise dose escalation and validated by 3D cultures and unbiased antibody arrays. ResultsAnalysis of the response of stage IV TNBC tumors treated with six common chemotherapy regimens resulted in 36% complete response and 64% partial response with residual tumor sizes ranging from 0.5 to 37.0 mm. Treatment of TNBC cells with chemotherapy agents led to distinct resistance signatures including downregulation of survivin and upregulation of M-CSF and CXCL8/IL-8 in model mesenchymal-like, and upregulation of CCL2/MCP-1, CTSS and DKK-1 in model epithelial TNBC cells. The inhibitory phosphorylation of GSK-3{beta} (p-S9) increased in paclitaxel resistant epithelial cells but decreased in resistant mesenchymal-like TNBC cells. Finally, chemotherapy resistance also activated p90 ribosomal S6 kinases (RSK1/2) in both cell types, while activation of mitogen- and stress-activated kinases (MSK1/2) was only observed in chemotherapy resistant epithelial TNBC cells. ConclusionsThese data reveal that chemotherapy resistance of epithelial and mesenchymal-like TNBC cellular subsets upregulated distinct profiles of proinflammatory and immune cell chemotactic cytokines and modulated the activities of GSK-3{beta}, p90 RSK1/2 and the related MSK1/2. Targeting these factors and/or the associated signaling pathways may help overcome chemotherapy resistance in TNBC. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/685128v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@1c5481dorg.highwire.dtl.DTLVardef@101a766org.highwire.dtl.DTLVardef@1954523org.highwire.dtl.DTLVardef@ee2ddb_HPS_FORMAT_FIGEXP M_FIG C_FIG TNBC tumors are typically heterogeneous, predominantly epithelial tissues with discrete patches of mesenchymal-like TNBC cells, that differ in their invasiveness, proliferation potential and response to treatment. This study reveals that Chemotherapy resistance in epithelial and mesenchymal-like TNBC cells is maintained by distinct signatures of proinflammatory and immune cell chemotactic cytokines, and activities of GSK-3{beta} and p90 ribosomal S6 kinases.

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Vuong, N. B., korolkova, O. Y., Izban, M., SAKWE, N. I., McIntosh, A. R., Ball, D., Black, P. J., Edwards, A., Ballard, B. R., Adunyah, S. E., Sakwe, A. M.. 2025-11-03. Contribution of Mesenchymal-like and Epithelial Cellular Subsets to Chemotherapy Resistance in Triple-Negative Breast Cancer. https://doi.org/10.1101/2025.11.01.685128

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