Irradiation induces DJ-1 secretion from esophageal squamous cell carcinoma cells to accelerate metastasis of bystander cells via a TGF-β1 positive feedback loop

• DOI: 10.1186/s13046-022-02471-6
• Publication Date: 2022-08-26T03:27:52Z
• Authors: Junjie Gu; Yuanyuan Sun; Jiahang Song; Ruiling Zhao; Xiaoke Di; Yumeng Zhang; Xiaolin Ge; Shu Zhang; Yun Gu; Xinchen Sun
• Keywords: DJ-1; 0303 health sciences; HSC70; Esophageal Neoplasms; Research; Neoplasms. Tumors. Oncology. Including cancer and carcinogens; Feedback; 3. Good health; TSP1; Gene Expression Regulation, Neoplastic; Transforming Growth Factor beta1; 03 medical and health sciences; Esophageal squamous cell carcinoma; Cell Movement; TGF-β1; Cell Line, Tumor; Humans; Esophageal Squamous Cell Carcinoma; RC254-282; Smad3; Cell Proliferation

Abstract Background Radiation-induced bystander effect (RIBE) can promote tumor metastasis contributing to the failure of radiotherapy for esophageal squamous cell carcinoma (ESCC). Aberrant expression of DJ-1 has been identified in ESCC; however, the relationship between DJ-1 and RIBE in ESCC remains unknown.

Methods We detected DJ-1 in the serum and cell supernatants by enzyme-linked immunosorbent assay (ELISA) and evaluated tumor metastasis by phenotypic experiments in vivo and in vitro. RNA-seq, mass spectrometry, western blot (WB), immunoprecipitation (IP), and dual-luciferase reporter assays were performed to explore the underlying mechanisms.

Results DJ-1 was highly expressed in the serum of patients with ESCC receiving radiotherapy and was significantly overexpressed in the medium of ESCC cells receiving irradiation. DJ-1 promoted tumor metastasis via the TGF-β1 pathway. Mechanistic studies revealed that DJ-1 bound to HSC70 to promote Smad3 phosphorylation and nuclear aggregation in a protein-interaction manner, which activated the transcription of Thrombospondin-1 (TSP1). Subsequently, the activation of TGF-β1 by TSP1 re-promoted Smad3 phosphorylation and nuclear aggregation, constituting a positive feedback loop to strengthen the metastasis of ESCC cells, which was effectively blocked by LY2109761 and LSKL. Moreover, higher levels of serum DJ-1 in patients with ESCC were related to a poorer prognosis of radiotherapy.

Conclusions Irradiation can induce ESCC cells secreting DJ-1. Secreted DJ-1 enters bystander cells to initiate activation of the TGF-β1 pathway via the DJ-1/HSC70/Smad3 signaling axis. The TSP1/TGF-β1/Smad3 positive feedback pathway constitutes the core pathway that promotes ESCC metastasis. DJ-1 is a useful biomarker for predicting the efficacy of radiotherapy and a potential therapeutic target for reversing RIBE in ESCC.

Graphical Abstract Schematic diagram showing the underlying mechanism that irradiation-induced secretion of DJ-1 accelerates the metastasis of bystander ESCC cells.