RESUMEN
Breast tumor-initiating cells (BTICs) of triple-negative breast cancer (TNBC) tissues actively repair DNA and are resistant to treatments including chemotherapy, radiotherapy, and targeted therapy. Herein, it is found that a previously reported secreted protein, sclerostin domain containing 1 (SOSTDC1), is abundantly expressed in BTICs of TNBC cells and positively correlated with a poor patient prognosis. SOSTDC1 knockdown impairs homologous recombination (HR) repair, BTIC maintenance, and sensitized bulk cells and BTICs to Olaparib. Mechanistically, following Olaparib treatment, SOSTDC1 translocates to the nucleus in an importin-α dependent manner. Nuclear SOSTDC1 interacts with the N-terminus of the nucleoprotein, chromatin helicase DNA-binding factor (CHD1), to promote HR repair and BTIC maintenance. Furthermore, nuclear SOSTDC1 bound to ß-transducin repeat-containing protein (ß-TrCP) binding motifs of CHD1 is found, thereby blocking the ß-TrCP-CHD1 interaction and inhibiting ß-TrCP-mediated CHD1 ubiquitination and degradation. Collectively, these findings identify a novel nuclear SOSTDC1 pathway in regulating HR repair and BTIC maintenance, providing insight into the TNBC therapeutic strategies.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Proteínas de Unión al ADN , Ftalazinas , Piperazinas , Neoplasias de la Mama Triple Negativas , Humanos , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Femenino , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Piperazinas/farmacología , Ftalazinas/farmacología , Ratones , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Línea Celular Tumoral , Animales , Resistencia a Antineoplásicos/genética , Reparación del ADN por Recombinación/genética , Progresión de la Enfermedad , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/efectos de los fármacos , Modelos Animales de Enfermedad , Núcleo Celular/metabolismo , ADN HelicasasRESUMEN
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited therapeutic options. IL1 receptor type 2 (IL1R2) promotes breast tumor-initiating cell (BTIC) self-renewal and tumor growth in TNBC, indicating that targeting it could improve patient treatment. In this study, we observed that IL1R2 blockade strongly attenuated macrophage recruitment and the polarization of tumor-associated macrophages (TAM) to inhibit BTIC self-renewal and CD8+ T-cell exhaustion, which resulted in reduced tumor burden and prolonged survival in TNBC mouse models. IL1R2 activation by TAM-derived IL1ß increased PD-L1 expression by interacting with the transcription factor Yin Yang 1 (YY1) and inducing YY1 ubiquitination and proteasomal degradation in both TAMs and TNBC cells. Loss of YY1 alleviated the transcriptional repression of c-Fos, which is a transcriptional activator of PDL-1. Combined treatment with an IL1R2-neutralizing antibodies and anti-PD-1 led to enhanced antitumor efficacy and reduced TAMs, BTICs, and exhausted CD8+ T cells. These results suggest that IL1R2 blockade might be a strategy to potentiate immune checkpoint blockade efficacy in TNBC to improve patient outcomes. Significance: IL1R2 in both macrophages and breast cancer cells orchestrates an immunosuppressive tumor microenvironment by upregulating PD-L1 expression and can be targeted to enhance the efficacy of anti-PD-1 in triple-negative breast cancer.
Asunto(s)
Neoplasias de la Mama Triple Negativas , Neoplasias de la Mama Triple Negativas/inmunología , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/patología , Neoplasias de la Mama Triple Negativas/metabolismo , Animales , Ratones , Humanos , Femenino , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Linfocitos T CD8-positivos/inmunología , Microambiente Tumoral/inmunología , Microambiente Tumoral/efectos de los fármacos , Macrófagos Asociados a Tumores/inmunología , Macrófagos Asociados a Tumores/metabolismo , Macrófagos Asociados a Tumores/efectos de los fármacos , Línea Celular Tumoral , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/metabolismo , Factor de Transcripción YY1/metabolismo , Factor de Transcripción YY1/genética , Ensayos Antitumor por Modelo de Xenoinjerto , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/inmunología , Células Madre Neoplásicas/patología , Células Madre Neoplásicas/efectos de los fármacosRESUMEN
Tumor-resident microbiota in breast cancer promotes cancer initiation and malignant progression. However, targeting microbiota to improve the effects of breast cancer therapy has not been investigated in detail. Here, we evaluated the microbiota composition of breast tumors and found that enterotoxigenic Bacteroides fragilis (ETBF) was highly enriched in the tumors of patients who did not respond to taxane-based neoadjuvant chemotherapy. ETBF, albeit at low biomass, secreted the toxic protein BFT-1 to promote breast cancer cell stemness and chemoresistance. Mechanistic studies showed that BFT-1 directly bound to NOD1 and stabilized NOD1 protein. NOD1 was highly expressed on ALDH+ breast cancer stem cells (BCSCs) and cooperated with GAK to phosphorylate NUMB and promote its lysosomal degradation, thereby activating the NOTCH1-HEY1 signaling pathway to increase BCSCs. NOD1 inhibition and ETBF clearance increase the chemosensitivity of breast cancer by impairing BCSCs.