RESUMO
Esophageal squamous cell carcinoma (ESCC) is a prevalent malignancy of the digestive system. Hypoxia is a crucial player in tumor ferroptosis resistance. However, the molecular mechanism of hypoxia-mediated ferroptosis resistance in ESCC remains unclear. Here, USP2 expression was decreased in ESCC cell lines subjected to hypoxia treatment and was lowly expressed in clinical ESCC specimens. Ubiquitin-specific protease 2 (USP2) depletion facilitated cell growth, which was blocked in USP2-overexpressing cells. Moreover, USP2 silencing enhanced the iron ion concentration and lipid peroxidation accumulation as well as suppressed ferroptosis, while upregulating USP2 promoted ferroptotic cell death in ESCC cells. Furthermore, knockout of USP2 in ESCC models discloses the essential role of USP2 in promoting ESCC tumorigenesis and inhibiting ferroptosis. In contrast, overexpression of USP2 contributes to antitumor effect and ferroptosis events in vivo. Specifically, USP2 stably bound to and suppressed the degradation of nuclear receptor coactivator 4 (NCOA4) by eliminating the Lys48-linked chain, which in turn triggered ferritinophagy and ferroptosis in ESCC cells. Our findings suggest that USP2 plays a crucial role in iron metabolism and ferroptosis and that the USP2/NCOA4 axis is a promising therapeutic target for the management of ESCC.
Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Ferroptose , Ubiquitina Tiolesterase , Humanos , Ferroptose/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/genética , Ubiquitina Tiolesterase/metabolismo , Ubiquitina Tiolesterase/genética , Animais , Camundongos , Linhagem Celular Tumoral , Coativadores de Receptor Nuclear/metabolismo , Coativadores de Receptor Nuclear/genética , Regulação Neoplásica da Expressão Gênica , Ferritinas/metabolismo , Ferritinas/genética , Camundongos Nus , Autofagia/genética , Hipóxia/metabolismo , Proliferação de Células/genética , MasculinoRESUMO
BACKGROUND AND AIM: The high-mobility group box 1 (HMGB1) protein plays an important role in a lot of biological behaviors, including DNA damage repair, gene transcription, cell replication, and cell death, and its expression is higher in many solid tumors tissues than in their adjacent normal tissues, and it is always involved in tumor proliferation, metastasis, therapeutic tolerance, and poor prognosis. However, HMGB1 in proliferation and radioresistance of esophageal squamous cell carcinoma (ESCC) remains poorly understood. In this study, the effect of HMGB1 on proliferation, cell death, DNA damage repair and radioresistance, and its underlying mechanism was investigated in human ESCC. METHODS: The immunohistochemistry scores of tumor and adjacent normal tissues in ESCC tissue microarray were analyzed. Stable HMGB1 knockdown cell lines were constructed using Kyse150 and Kyse450 cells. Cell viability, radioresistance, apoptosis, autophagy, and DNA damage were determined using CCK-8, 5-ethynyl-2'-deoxyuridine, clonogenic survival assay, immunofluorescence, flow cytometry, and western blot assays. RESULTS: Differential analyses showed that the expression of HMGB1 in esophageal cancer tissue was significantly higher than that in adjacent normal tissues. The downregulation of HMGB1 could effectively inhibit proliferation, increase radiosensitivity, impair DNA damage repair abilities, reduce autophagy, and increase apoptosis rates in ESCC cells after irradiation. CONCLUSIONS: HMGB1 is expected to be a potential target for ESCC therapy and radiosensitization.
Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Proliferação de Células/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Proteína HMGB1/fisiologia , Tolerância a Radiação/genética , Apoptose/genética , Autofagia/genética , Carcinoma de Células Escamosas/terapia , Morte Celular/genética , Dano ao DNA/genética , Reparo do DNA/genética , Neoplasias Esofágicas/terapia , Humanos , Terapia de Alvo Molecular , Células Tumorais CultivadasRESUMO
Endocrine therapy and radiotherapy are the main treatments for luminal A breast cancer. However, drug and radiotherapy resistance could occur during long-term treatment, leading to local recurrence and distant metastasis. Some studies have found that drug resistance might be related to human epidermal growth factor receptor-3 (HER3) overexpression. However, whether HER3 plays a role in radiotherapy resistance is unknown. The purpose of this study is to elucidate the effect of HER3 in radiotherapy and to assess whether HER3 could be a potential target for radiosensitivity. We used retroviruses to construct stable low expression of HER3 in MCF-7 and ZR75-1cells. The CCK-8 assay was used to observe proliferation. Colony-forming assay was used to detect radiosensitivity. Flow cytometry was used to observe the cell cycle and apoptosis. Immunofluorescence assay was used to detect the number of γH2AX foci in the nucleus with or without ionizing radiation (IR). Western blot analysis was used to verify the change of relative proteins. Nude mice were used to observe tumor growth in vivo. In our study, silencing HER3 reduced cell proliferation and clone formation ability after IR, so silencing HER3 increased the sensitivity of luminal A breast cancer cells to radiotherapy. In terms of radiosensitivity mechanisms, it is suggested that the silencing of HER3 enhanced IR-induced DNA damage, reduced DNA repair, and increased apoptosis and G2 /M arrest. In addition, silencing HER3 combined with IR clearly inhibited the transplanted tumor growth in vivo. Therefore, we concluded that HER3 played a role in radiotherapy resistance. Silencing HER3 increased the radiosensitivity of luminal A breast cancer cells and HER3 could be a potential target for radiosensitivity.