Related Experiment Video
Updated: Jul 11, 2025
Testing Cancer Immunotherapeutics in a Humanized Mouse Model Bearing Human Tumors
Published on: December 16, 2022
MDR1-EXPRESSING CD4+ T CELLS WITH TH1.17 FEATURES RESIST TO NEOADJUVANT CHEMOTHERAPY AND ARE ASSOCIATED WITH BREAST
Anthony Di Roio1, Margaux Hubert1, Laurie Besson1
1TERI Department, Centre de Recherche en Cancerologie de Lyon, Lyon, France.
Background:
Multidrug resistance-1 (MDR1) transporter limits the intracellular accumulation of chemotherapies (paclitaxel, anthracyclines) used in breast cancer (BC) treatment. In addition to tumor cells, MDR1 is expressed on immune cell subsets in which it confers chemoresistance. Among human T cells, MDR1 is expressed by most CD8+ T cells, and a subset of CD4+ T helper (Th) cells. Here we explored the expression, function and regulation of MDR1 on CD4+ T cells and investigated the role of this population in response to neoadjuvant chemotherapy (NAC) in BC.
Methods:
Phenotypic and functional characteristics of MDR1+ CD4 Th cells were assessed on blood from healthy donors and patients with BC by flow cytometry. These features were extended to CD4+ Th cells from untreated breast tumor by flow cytometry and RNA-sequencing (RNA-seq). We performed in vitro polarization assays to decipher MDR1 regulation on CD4 Th cells. We evaluated in vitro the impact of chemotherapy agents on MDR1+ CD4+ Th cells. We analyzed the impact of NAC treatment on MDR1+ CD4+ Th cells from blood and tumors and their association with treatment efficacy in two independent BC cohorts and in a public RNA-seq data set of BC tumor biopsies before and after NAC. Finally, we performed single cell (sc) RNAseq of blood CD4+ memory T cells from NAC-treated patients and combined them with an scRNAseq public data set.
Results:
MDR1+ CD4 Th cells were strongly enriched in Th1.17 polyfunctional cells but also in Th17 cells, both in blood and untreated breast tumor tissues. Mechanistically, Tumor growth factor (TGF)-β1 was required for MDR1 induction during in vitro Th17 or Th1.17 polarization. MDR1 expression conferred a selective advantage to Th1.17 and Th17 cells following paclitaxel treatment in vitro and in vivo in NAC-treated patients. scRNAseq demonstrated MDR1 association with tumor Th1.17 and Th with features of cytotoxic cells. Enrichment in MDR1+ CD4+ Th1.17 and Th17 cells, in blood and tumors positively correlated with pathological response. Absence of early modulation of Th1.17 and Th17 in NAC-resistant patients, argue for its use as a biomarker for chemotherapy regimen adjustment.
Conclusion:
MDR1 favored the enrichment of Th1.17 and Th17 in blood and tumor after NAC that correlated to clinical response.
Insights
Multidrug resistance-1 (MDR1) transporter expression on CD4+ T cells, particularly Th1.17 and Th17 subsets, is linked to chemotherapy response in breast cancer (BC). Targeting MDR1+ cells may improve treatment efficacy.
Area of Science:
- Immunology
- Cancer Biology
- Pharmacology
Background:
- Multidrug resistance-1 (MDR1) transporter limits chemotherapy efficacy in breast cancer (BC) by reducing drug accumulation in tumor cells.
- MDR1 is also expressed on immune cells, including CD4+ T helper (Th) cells, conferring chemoresistance.
- The role of MDR1 on CD4+ T cells in BC response to neoadjuvant chemotherapy (NAC) requires further investigation.
Purpose of the Study:
- To explore the expression, function, and regulation of MDR1 on CD4+ T cells.
- To investigate the role of MDR1+ CD4+ T cells in response to NAC in breast cancer.
- To assess the potential of MDR1+ CD4+ T cells as biomarkers for treatment efficacy.
Main Methods:
- Flow cytometry and RNA-sequencing (RNA-seq) to characterize MDR1+ CD4+ Th cells in blood and tumor tissues.
- In vitro polarization assays to study MDR1 regulation on CD4+ Th cells.
- Evaluation of chemotherapy impact on MDR1+ CD4+ Th cells and analysis of NAC treatment effects in BC cohorts.
Main Results:
- MDR1+ CD4+ Th cells were enriched in Th1.17 and Th17 subsets in both blood and tumor tissues.
- Tumor growth factor-β1 was essential for MDR1 induction in Th17 and Th1.17 cells.
- MDR1 expression provided a survival advantage to Th1.17 and Th17 cells during paclitaxel treatment.
- Enrichment of MDR1+ CD4+ Th1.17 and Th17 cells correlated positively with pathological response to NAC.
- Early lack of modulation in Th1.17 and Th17 cells predicted NAC resistance.
Conclusions:
- MDR1 promotes the enrichment of Th1.17 and Th17 cells in blood and tumors following NAC, correlating with clinical response.
- MDR1+ CD4+ T cells, specifically Th1.17 and Th17 subsets, are associated with treatment efficacy in breast cancer.
- The modulation patterns of Th1.17 and Th17 cells may serve as biomarkers for adjusting chemotherapy regimens.
