Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Combination therapy with docetaxel and mSTAR1302 elicits antitumor effects in triple negative breast cancer (4T1) and androgen-independent prostate cancer (TRAMP-C2) mouse models. (A–E) 8–12-week-old female Balb/c mice were inoculated subcutaneously with 5x10 4 4T1 in the mammary fat pad (n=8–10 per group). (A) pictogram depicts experimental design. When the tumors reached 40-70mm 3 , mice were administered 3 doses of mSTAR1302 (1 mg/kg, i.p.) once per week on days 9, 16, and 23 and 3 doses of docetaxel (500 µg, i.p.), every other day, 7 days post-initial mSTAR1302 treatment, on days 16, 18, and 20. Primary tumors were measured in terms of mean (B) and individual (C) tumor volumes, as depicted. Inset numbers are tumor-free mice. In two additional cohorts, to assess metastatic growth, lungs were removed from 4T1 tumor-bearing mice 28 days post-tumor inoculation following the same treatment schedule. Lungs were dissociated, cultured in medium (2x FBS with 6-thioguanine) and incubated at 37 °C with 5% CO 2 for 12 days. (D) a meta-analysis from two separate studies is depicted with closed and opened circles differentiating data collected from each study. Cell colonies representing lung metastases were stained with 0.05% methylene blue and counted for each treatment group (n=14–20 per group total). Survival (E) was measured over time with inset numbers depicting median overall survival (mOS) and shaded bands depicting 95% confidence intervals. (F–I) 8–12-week-old male C57bl/6 mice were inoculated subcutaneously with 2.5x10 6 TRAMP-C2, on the right flank (n=8–10 per group). (F) pictogram depicts experimental design. Mice were administered mSTAR1302 (1 mg/kg, i.p.) when tumors reached 70–100mm 3 on days 22, 29, and 36, and docetaxel (500 µg, i.p.) on days 29, 31, and 33. Tumors were measured with mean (G) and individual (H) tumor volumes depicted. Inset numbers are tumor-free mice. Survival (I) was measured over time with mOS and 95% confidence intervals (shaded bands) depicted. Statistical tests: tumor growth: two-way ANOVA with Tukey’s post hoc test; comparison between groups: one-way ANOVA with Tukey’s post hoc test; survival; Mantel-Cox test. Error bars, SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ANOVA, analysis of variance; FBS, fetal bovine serum; i.p., intraperitoneal; mets, metastases; s.c., subcutaneously.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Cell Culture, Incubation, Staining, Comparison

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Docetaxel induces upregulation of death receptors TRAIL-R2 and FAS in 4T1 and TRAMP-C2 cells. (A) 4T1 and TRAMP-C2 cells were treated in vitro with either no drug or docetaxel (250 ng/mL) for 48 hours and analyzed for surface expression of FAS and TRAIL-R2 via flow cytometry. Histograms indicating frequency and gMFI are shown. Experiment repeated twice with similar results. (B) 4T1 and TRAMP-C2 cells were treated as described in Figure 1A and then co-cultured with TRAIL ligand or FAS ligand and protein G and measured for relative cell lysis compared to cells alone. (C, D) tumors harvested on day 28, after treatment as described in Figure 1A , were fixed for multiplex immunofluorescence staining and quantified for CD8 (green) and TRAIL-R2 or FAS (red) expression. (E) differential gene expression was interrogated using NanoString murine PanCancer immune profiling panel on tumors harvested on day 23 from 4T1 tumor-bearing Balb/c female mice, following treatment as previously described. Fold change compared to untreated tumors reported for TRAIL and FAS ligands. (F) 4T1 cells were exposed to docetaxel (250 ng/mL) for 48 hours and co-cultured with NK cells isolated from tumor-free Balb/c mice (E:T = 25:1) and monitored for relative NK-specific lysis of tumor cells for up to 8 hours post-effector addition. Statistical tests: comparison between groups: One-way ANOVA with Tukey’s post hoc test. comparison between two groups: unpaired T-test. Error bars, SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ANOVA, analysis of variance; FoV, field of view; gMFI, geometric mean fluorescence intensity; NK, natural killer.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: In Vitro, Expressing, Flow Cytometry, Cell Culture, Lysis, Multiplex Assay, Immunofluorescence, Staining, Gene Expression, Isolation, Comparison, Fluorescence

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Antitumor activity of docetaxel and mSTAR1302 attenuated in TRAIL-R2 knockdown tumor mouse models. (A) TRAIL-R2 was knocked down via CRISPR in TRAMP-C2 and 4T1 cell lines. Flow cytometry was used to confirm expression in clones and WT cell lines. (B) 8–12-week-old male C57bl/6 mice were implanted with 2.5x10 6 TRAMP-C2 (n=10–12 per group) or TRAMP-C2 TRAIL-KO (n=7–9 per group) cells in the right flank. Treatment schedules for each group are depicted. Mean tumor volumes graphed. (C) 8–12-week-old female Balb/c mice were implanted with 5x10 4 4T1 (n=18–20 per group) or 4T1 TRAIL KO cells (n=10) in the mammary fat pad. WT 4T1 mice from this study were assessed concurrently in the study from Figure 7 and mean tumor volumes displayed in Figure 7C are the same tumor volumes displayed in Figure 7B . Statistical tests: tumor growth: two-way ANOVA with Tukey’s post hoc test. Error bars, SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. WT, wild type; KO, knockouts; CRISPR, clustered regularly interspaced short palindromic repeats; i.p., intraperitoneal; s.c., subcutaneously; ns, not significant.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Activity Assay, Knockdown, CRISPR, Flow Cytometry, Expressing, Clone Assay

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Co-treatment of 4T1 tumors with docetaxel and mSTAR1302 enhances tumor-infiltrating lymphocytes. RNA was isolated from tumors collected on day 23 from 4T1 tumor-bearing Balb/c female mice, following treatment, as previously described in Figure 1A . RNA analysis performed via NanoString murine PanCancer immune profiling panel. Heatmaps displaying (A) the top 10 differentially upregulated and downregulated genes by fold change for treatment groups compared to control, weighted by combination, and (B) a cell profiling analysis normalized via an abundance score. DC, dendritic cells; NK, natural killer cells; Th1, T helper 1 cells; Tregs, regulatory T cells.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Isolation, Control

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Vβ13 T cells are upregulated with docetaxel and mSTAR1302 combination treatment in 4T1 triple negative breast cancer model. Balb/c mice were inoculated with 4T1 cells on day 0 and treated with mSTAR1302 and docetaxel as previously described in Figure 1A . Tumors were harvested, processed, and stained on day 23. Flow cytometry was performed to determine the frequency of (A) CD4 and (B) CD8 T cells, which were further analyzed for expression of Vβ13 (Vβ8.1), (C) Tregs, (D) NK cells, (E) MDSCs, and (F) macrophages, which were further analyzed to determine M1, M2, and M1:M2 status. Statistical tests: comparison between groups: one-way ANOVA with Tukey’s post hoc test. Error bars, SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ANOVA, analysis of variance; MDSCs, myeloid-derived suppressor cells; NK, natural killer cells; Tregs, regulatory T cells.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Staining, Flow Cytometry, Expressing, Comparison, Derivative Assay

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Docetaxel and mSTAR1302 antitumor immune response dependent on CD4+ T, CD8+ T, and NK cell activity. Female Balb/c mice were implanted with 4T1 tumors and treated as described in Figure 1A with docetaxel and mSTAR1302. (B, D, H) anti-CD4 (100 μg, i.p.) and (C, D, H) anti-CD8 depleting antibodies were administered on days 6, 7, and 8, post-tumor implantation and then once every 7 days thereafter. (E) an anti-Vβ13 (1 mg/kg, i.p.) depleting antibody was administered on days 6 and 8, and every 7 days thereafter. (F) anti-IFN-γ (100 μg, i.p.) was administered 2 days prior to, the same day as, and 2 days following mSTAR1302 treatment (i.e., days 7, 9, 11, 14, 16, 18, 21, 23, and 25). (G, H) anti-NK–depleting antibody (25 µl in 100 µl of PBS, i.p.) was administered on days 5 and 7 and then every 5 days subsequently. (A–H) mean tumor volume displayed. Statistical tests: tumor growth: two-way ANOVA with Tukey’s post hoc test; error bars, SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ANOVA, analysis of variance; anti, antibody; IFN-γ, interferon gamma; i.p., intraperitoneal; ns, not significant; NK, natural killer.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Activity Assay, Tumor Implantation

Journal: Frontiers in Immunology

Article Title: Docetaxel enhances Vβ-directed T-cell activation and antitumor immunity mediated by a bifunctional TCR agonist in breast and prostate cancer models

doi: 10.3389/fimmu.2026.1850760

Figure Lengend Snippet: Docetaxel and mSTAR1302 co-treatment promote antigen-specific T cells in the 4T1 tumor model. Female Balb/c 4T1 tumor-bearing mice were treated with mSTAR1302 and docetaxel as previously described (n=20/group). (A) pictogram depicts experimental design. (B) mean and individual tumor volumes recorded over time. On day 23, the spleens of 8 mice per group were surgically excised and processed. Splenocytes were plated on ELISPOT plates coated with IFN-γ–specific capture antibody and co-cultured with AH1 peptide, CD3/CD28 antibody as a positive control, or β-gal overnight, then developed with detection antibody. β-gal was used to normalize data to account for non-specific binding and background. ELISPOT plates were pictured (C) and quantified (D) for total number of spots. Statistical tests: tumor growth: two-way ANOVA with Tukey’s post hoc test. Comparison between groups: one-way ANOVA with Tukey’s post hoc test. Error bars, SEM. *p < 0.05, ***p < 0.001, ****p < 0.0001. ANOVA, analysis of variance; IFN-γ, interferon gamma; i.p., intraperitoneal; s.c., subcutaneously; SFC, spot-forming cells.

Article Snippet: Wild-type (WT) female Balb/c mice and WT male C57BL/6 mice were obtained from Charles River Laboratory (Wilmington, MA, USA) or bred in-house at the National Institutes of Health (NIH; Bethesda, MD, USA).

Techniques: Enzyme-linked Immunospot, Cell Culture, Positive Control, Binding Assay, Comparison