HBEGF通过调控CXCL8募集肿瘤相关中性粒细胞促进膀胱癌化疗耐药的机制研究

化疗耐药是膀胱癌复发和治疗失败的主要原因之一，但肿瘤微环境中的免疫细胞在其中的作用未明。我们发现肿瘤相关中性粒细胞（TANs）在化疗抵抗的膀胱癌组织高度浸润，并且促进肿瘤细胞的化疗拮抗能力。为了探索TANs的浸润机制，我们建立了膀胱癌化疗耐药细胞株，发现HBEGF在耐药株和化疗抵抗的癌组织中高表达，与患者不良预后相关，并且增强膀胱癌细胞在体内外的化疗拮抗能力。测序发现HBEGF调控CXCL8的表达，进而影响膀胱癌细胞的化疗敏感性和趋化中性粒细胞的能力。由此我们提出：HBEGF通过转录激活CXCL8，募集中性粒细胞浸润至肿瘤组织，进而导致膀胱癌的化疗耐药。本研究拟进一步采用体内外实验、免疫共沉淀、共培养等实验获得HBEGF通过调控CXCL8介导TANs浸润促进膀胱癌耐药的证据，明确其临床意义，为发现预测化疗敏感性的标记物和提高化疗疗效的新靶点提供理论基础，为膀胱癌精准诊疗提供新策略。

Chemoresistance is the main reason of relapse and treatment failure in bladder cancer, but the roles and mechanism of the tumor microenvironment-associated immune cells in chemoresistance of bladder cancer remain unknown. We found that tumor-associated neutrophils (TANs) were markedly enriched in chemotherapy nonresponders than responders, and promoted the chemoresistance of bladder cancer cells in vitro. To explore the mechanism of TANs recruitment, chemoresistant bladder cancer cells were established, and HBEGF was identified significantly upregulated in chemoresistant bladder cancer cell sublines and tumor tissues, and its expression level was correlated with overall survival of bladder cancer patients. Through gain or loss of function, we found that HBEGF significantly promoted the chemoresistance of bladder cancer cells in vitro and in vivo. Furthermore, HBEGF regulated the transcriptional expression of CXCL8, enhancing the chemoresistance of bladder cancer cells and recruitment of TANs. Therefore, we propose a new mechanism that HBEGF recruits TANs infiltrating in tumor tissues through regulating transcription of CXCL8, ultimately driving chemoresistance of bladder cancer. We will perform in vitro and in vivo functional experiments, co-immunoprecipitation and co-culture experiments to further gain the proof of HBEGF regulates chemoresistance of bladder cancer via CXCL8-mediated recruiting TANs. This study intends to demonstrate the function and mechanism of HBEGF in bladder cancer, and clarify the clinical significance of HBEGF in bladder cancer recurrence, therapy resistance and prognosis, and identify the novel diagnostic biomarker and therapeutic target for chemoresistant bladder cancer.