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HMGB3 Contributes to Anti-PD-1 Resistance by Inhibiting IFN-γ-Driven Ferroptosis in TNBC
Bo Luo1,2,3, Hongmei Zheng2,3,4, Gai Liang1
1Department of Radiotherapy Center, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Abstract:
Our previous studies showed HMGB3 expression may correlate with immunotherapy efficacy in breast cancer patients. Here, we investigated whether HMGB3 overexpression has an impact on anti-PD-1 therapy in triple-negative breast cancer (TNBC) and its molecular mechanisms. Animal models were established to observe the effect of HMGB3 on sensitivity to anti-PD-1 treatment. Correlation of HMGB3 expression and ferroptosis preventive proteins in TNBC patients' tissues with anti-PD-1 therapy efficacy was analyzed. The impact of HMGB3 on IFN-γ (Interferon-gamma) inhibitory effects and signaling was examined in human TNBC cells where HMGB3 expression was knocked down using siRNA. Moreover, TNBC cells stably transfected with lentiviral vectors containing cDNA of HMGB3 were also used to confirm the effect of overexpression of HMGB3 on IFN-γ inhibitory effect and signaling. Effect of HMGB3 on IFN-γ-driven ferroptosis and ferroptosis-associated protein expression were also investigated. Correlation of HMGB3 and IRF1 and GPX4 expression in patient's cancer tissue were also investigated. Our results demonstrated that HMGB3 expression contributes to resistance to anti-PD-1 therapy in vivo. HMGB3 expression correlated with treatment efficacy of immunotherapy and survival in TNBC patients. HMGB3 silence decreased resistance of breast cancer cells to IFN-γ cytotoxic effect, while HMGB3 overexpression increased resistance of these cancer cells. HMGB3 silence increased STAT1 phosphorylation and IRF1 expression upon IFN-γ treatment compared with control. Overexpression of HMGB3 inhibited STAT1 phosphorylation and IFN-γ signaling in TNBC cells. Moreover, HMGB3 also increased STAT3 activation and had an effect of interaction between STAT1 and STAT3. HMGB3 overexpression decreased IFN-γ-driven ferroptosis in TNBC cells. HMGB3 increased ferroptosis-inhibitory proteins (SLC7A11, GPX4, and SLC3A2) expression in TNBC cells. Ferroptosis inhibition recovers resistance to anti-PD-1 therapy in vivo. Immunohistochemistry showed HMGB3 expression correlated with ferroptosis-associated proteins and IRF1 expression in breast cancer tissue. HMGB3 contributes to anti-PD-1 resistance by inhibiting IFN-γ-driven ferroptosis in TNBC which suggested HMGB3 is a potential co-target with anti-PD-1 therapy for TNBC.
Insights
High mobility group box 3 (HMGB3) overexpression promotes resistance to anti-PD-1 immunotherapy in triple-negative breast cancer (TNBC) by inhibiting interferon-gamma (IFN-γ)-driven ferroptosis. Targeting HMGB3 may enhance anti-PD-1 therapy efficacy in TNBC patients.
Area of Science:
- Oncology
- Immunology
- Molecular Biology
Background:
- Previous studies indicated a correlation between HMGB3 expression and immunotherapy efficacy in breast cancer.
- Triple-negative breast cancer (TNBC) remains a challenging subtype with limited treatment options, particularly regarding immunotherapy response.
Purpose of the Study:
- To investigate the impact of HMGB3 overexpression on anti-PD-1 therapy efficacy in TNBC.
- To elucidate the molecular mechanisms by which HMGB3 influences anti-PD-1 therapy response, focusing on interferon-gamma (IFN-γ) signaling and ferroptosis.
Main Methods:
- Utilized animal models to assess HMGB3's effect on anti-PD-1 therapy sensitivity.
- Analyzed HMGB3 and ferroptosis-associated protein expression in TNBC patient tissues.
- Employed siRNA-mediated knockdown and lentiviral overexpression of HMGB3 in human TNBC cells to study IFN-γ signaling and ferroptosis.
- Investigated STAT1/STAT3 activation and ferroptosis-related protein expression (SLC7A11, GPX4, SLC3A2).
Main Results:
- HMGB3 overexpression conferred resistance to anti-PD-1 therapy in vivo and correlated with poorer treatment efficacy and survival in TNBC patients.
- HMGB3 knockdown sensitized breast cancer cells to IFN-γ cytotoxicity by enhancing STAT1 phosphorylation and IRF1 expression.
- HMGB3 overexpression inhibited IFN-γ signaling, STAT1 phosphorylation, and increased STAT3 activation, while decreasing IFN-γ-driven ferroptosis by upregulating ferroptosis-inhibitory proteins (SLC7A11, GPX4, SLC3A2).
- Inhibition of ferroptosis restored resistance to anti-PD-1 therapy in vivo.
Conclusions:
- HMGB3 contributes to anti-PD-1 resistance in TNBC by suppressing IFN-γ-induced ferroptosis.
- HMGB3 represents a potential co-targeting strategy to improve anti-PD-1 therapy outcomes in TNBC.
