Browsing by Author "Balko, JM"

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Activation of MAPK pathways due to DUSP4 loss promotes cancer stem cell-like phenotypes in basal-like breast cancer
(American Association for Cancer Research Inc., 2020) Balko, JM; Schwarz, LJ; Bhola, NE; Kurupi, R; Owens, P; Miller, TW; Gómez, H; Cook, RS; Arteaga, CL
Basal-like breast cancer (BLBC) is an aggressive disease that lacks a clinically approved targeted therapy. Traditional chemotherapy is effective in BLBC, but it spares the cancer stem cell (CSC)-like population, which is likely to contribute to cancer recurrence after the initial treatment. Dual specificity phosphatase-4 (DUSP4) is a negative regulator of the mitogen-activated protein kinase (MAPK) pathway that is deficient in highly aggressive BLBCs treated with chemotherapy, leading to aberrant MAPK activation and resistance to taxane-induced apoptosis. Herein, we investigated how DUSP4 regulates the MAP-ERK kinase (MEK) and c-jun-NH2-kinase (JNK) pathways in modifying CSC-like behavior. DUSP4 loss increased mammosphere formation and the expression of the CSC-promoting cytokines interleukin (IL)-6 and IL-8. These effects were caused in part by loss of control of the MEK and JNK pathways and involved downstream activation of the ETS-1 and c-JUN transcription factors. Enforced expression of DUSP4 reduced the CD44(+)/CD24(-) population in multiple BLBC cell lines in a MEK-dependent manner, limiting tumor formation of claudin-low SUM159PT cells in mice. Our findings support the evaluation of MEK and JNK pathway inhibitors as therapeutic agents in BLBC to eliminate the CSC population.
Effect of CCL5 expression in the recruitment of immune cells in triple negative breast cancer
(Nature Publishing Group, 2018) Araujo, JM; Gomez, AC; Aguilar, A; Salgado, R; Balko, JM; Bravo, L; Doimi, F; Bretel, D; Morante, Z; Flores, C; Gomez, HL; Pinto, JA
Triple negative breast cancer (TNBC) is the most aggressive form of breast cancer with limited options of targeted therapy. Recent findings suggest that the clinical course of TNBC may be modified by the presence of tumor-infiltrating lymphocytes (TILs) and chemokine's expression, such as CCL5. Diverse studies have shown that CCL5 suppresses anti-tumor immunity and it has been related to poor outcome in different types of cancer while in other studies, this gene has been related with a better outcome. We sought to determine the association of CCL5 with the recruitment of TILs and other immune cells. With this aim we evaluated a retrospective cohort of 72 TNBC patients as well as publicly available datasets. TILs were correlated with residual tumor size after neoadjuvant chemotherapy (NAC) and CCL5 expression. In univariate analysis, TILs and CCL5 were both associated to the distant recurrence free survival; however, in a multivariate analysis, TILs was the only significant marker (HR = 0.336; 95%IC: 0.150-0.753; P = 0.008). CIBERSORT analysis suggested that a high CCL5 expression was associated with recruitment of CD8 T cells, CD4 activated T cells, NK activated cells and macrophages M1. The CD8A gene (encoding for CD8) was associated with an improved outcome in several public breast cancer datasets.
Epithelial Expressed B7-H4 Drives Differential Immunotherapy Response in Murine and Human Breast Cancer
(American Association for Cancer Research Inc., 2024) Wescott, EC; Sun, X; Gonzalez-Ericsson, P; Hanna, A; Taylor, BC; Sanchez, V; Bronzini, J; Opalenik, SR; Sanders, ME; Wulfkuhle, J; Gallagher, RI; Gomez, H; Isaacs, C; Bharti, V; Wilson, JT; Ballinger, TJ; Santa-Maria, CA; Shah, PD; Dees, EC; Lehmann, BD; Abramson, VG; Hirst, GL; Swigart, LB; van't, Veer, LJ; Esserman, LJ; Petricoin, EF; Pietenpol, JA; Balko, JM
Combinations of immune checkpoint inhibitors (ICI, including anti-PD-1/PD-L1) and chemotherapy have been FDA approved for metastatic and early-stage triple-negative breast cancer (TNBC), but most patients do not benefit. B7-H4 is a B7 family ligand with proposed immunosuppressive functions being explored as a cancer immunotherapy target and may be associated with anti-PD-L1 resistance. However, little is known about its regulation and effect on immune cell function in breast cancers. We assessed murine and human breast cancer cells to identify regulation mechanisms of B7-H4 in vitro. We used an immunocompetent anti-PD-L1–sensitive orthotopic mammary cancer model and induced ectopic expression of B7-H4. We assessed therapy response and transcriptional changes at baseline and under treatment with anti-PD-L1. We observed B7-H4 was highly associated with epithelial cell status and transcription factors and found to be regulated by PI3K activity. EMT6 tumors with cell-surface B7-H4 expression were more resistant to immunotherapy. In addition, tumor-infiltrating immune cells had reduced immune activation signaling based on transcriptomic analysis. Paradoxically, in human breast cancer, B7-H4 expression was associated with survival benefit for patients with metastatic TNBC treated with carboplatin plus anti-PD-L1 and was associated with no change in response or survival for patients with early breast cancer receiving chemotherapy plus anti-PD-1. While B7-H4 induces tumor resistance to anti-PD-L1 in murine models, there are alternative mechanisms of signaling and function in human cancers. In addition, the strong correlation of B7-H4 to epithelial cell markers suggests a potential regulatory mechanism of B7-H4 independent of PD-L1. Significance: This translational study confirms the association of B7-H4 expression with a cold immune microenvironment in breast cancer and offers preclinical studies demonstrating a potential role for B7-H4 in suppressing response to checkpoint therapy. However, analysis of two clinical trials with checkpoint inhibitors in the early and metastatic settings argue against B7-H4 as being a mechanism of clinical resistance to checkpoints, with clear implications for its candidacy as a therapeutic target. © 2024 The Authors; Published by the American Association for Cancer Research.
NKG2A Is a Therapeutic Vulnerability in Immunotherapy Resistant MHC-I Heterogeneous Triple-Negative Breast Cancer
(American Association for Cancer Research Inc., 2024) Taylor, BC; Sun, X; Gonzalez-Ericsson, PI; Sanchez, V; Sanders, ME; Wescott, EC; Opalenik, SR; Hanna, A; Chou, S-T; Van, Kaer, L; Gomez, H; Isaacs, C; Ballinger, TJ; Santa-Maria, CA; Shah, PD; Dees, EC; Lehmann, BD; Abramson, VG; Pietenpol, JA; Balko, JM
Despite the success of immune checkpoint inhibition (ICI) in treating cancer, patients with triple-negative breast cancer (TNBC) often develop resistance to therapy, and the underlying mechanisms are unclear. MHC-I expression is essential for antigen presentation and T-cell–directed immunotherapy responses. This study demonstrates that TNBC patients display intratumor heterogeneity in regional MHC-I expression. In murine models, loss of MHC-I negates antitumor immunity and ICI response, whereas intratumor MHC-I heterogeneity leads to increased infiltration of natural killer (NK) cells in an IFNγ-dependent manner. Using spatial technologies, MHC-I heterogeneity is associated with clinical resistance to anti-programmed death (PD) L1 therapy and increased NK:T-cell ratios in human breast tumors. MHC-I heterogeneous tumors require NKG2A to suppress NK-cell function. Combining anti-NKG2A and anti–PD-L1 therapies restores complete response in heterogeneous MHC-I murine models, dependent on the presence of activated, tumor-infiltrating NK and CD8+ T cells. These results suggest that similar strategies may enhance patient benefit in clinical trials. SIGNIFICANCE: Clinical resistance to immunotherapy is common in breast cancer, and many patients will likely require combination therapy to maximize immunotherapeutic benefit. This study demonstrates that heterogeneous MHC-I expression drives resistance to anti–PD-L1 therapy and exposes NKG2A on NK cells as a target to overcome resistance.