Wang Ling, Yang Chao, Liu Xin-Bo, Wang Li, Kang Fu-Biao
1Department of Orthopedic Oncology, the Third Hospital of Hebei Medical University, Shijiazhuang, Hebei People's Republic of China.
2Department of General Surgery, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei People's Republic of China.
Cancer Cell Int. 2018 Jul 13;18:100. doi: 10.1186/s12935-018-0597-9. eCollection 2018.
The expression of the immunoregulatory protein B7-H4 has been reported in many types of cancer, including breast cancer. However, its role in triple-negative breast cancer (TNBC), especially its correlation with patients' prognosis and chemoresistance remains unclear.
The expression of B7-H4 in TNBC tissues and cell lines were measured with Real-Time PCR and western blotting. 65 cases of TNBC tissue samples and adjacent non-tumor tissue samples were analyzed by immunochemistry to demonstrate the correlation between the B7-H4 expression and clinicopathological characteristics. In vitro studies assessed mAb MIH43 alone and in combination with transfecting B7-H4 siRNA on the growth of chemosensitive and chemoresistant TNBC cell lines by CCK-8 and apoptotic enzyme-linked immunosorbent assay (ELISA).
B7-H4 expression was detected positive in 59 of 65 (90.8%) different stage TNBC patients, especially in the samples of recurrence TNBC patients after receiving neoadjuvant chemotherapy treatment. Survival curves showed that patients with B7-H4 overexpression had significantly shorter survival and recurrence time than those with low B7-H4 expression (< 0.005). Univariate and multivariate COX regression analysis demonstrated that B7-H4 was an independent predictor for advanced tumor stage. The monoclonal antibody of B7-H4 has the potential anti-proliferative effects on inhibiting the chemoresistant TNBC cell lines and increasing the sensitivity of TNBC cell lines to doxorubicin, paclitaxel or carboplatin. RNAi-mediated silencing of B7-H4 in TNBC cells enhanced drug-induced apoptosis via inhibiting PTEN/PI3K/AKT pathway, whereas reexpression of B7-H4 in B7-H4 knockdown and low B7-H4 expressing cells increased the phosphorylation of PI3K and AKT along with restoration of PETN expression.
Our data show that B7-H4 is a biomarker indicative of a poor prognosis in TNBC patients and at least partially downregulated in chemoresistance via PTEN/PI3K/AKT pathway. Targeting B7-H4 might provide an attractive therapeutic approach specifically for TNBC patients.
免疫调节蛋白B7-H4的表达已在包括乳腺癌在内的多种癌症类型中被报道。然而，其在三阴性乳腺癌（TNBC）中的作用，尤其是与患者预后和化疗耐药性的相关性仍不清楚。
采用实时定量PCR和蛋白质印迹法检测TNBC组织和细胞系中B7-H4的表达。通过免疫组织化学分析65例TNBC组织样本和相邻的非肿瘤组织样本，以证明B7-H4表达与临床病理特征之间的相关性。体外研究通过CCK-8和凋亡酶联免疫吸附测定（ELISA）评估单克隆抗体MIH43单独以及与转染B7-H4小干扰RNA联合使用对化疗敏感和化疗耐药的TNBC细胞系生长的影响。
在65例不同分期的TNBC患者中的59例（90.8%）检测到B7-H4表达呈阳性，尤其是在接受新辅助化疗治疗后的复发TNBC患者样本中。生存曲线显示，B7-H4过表达的患者比B7-H4低表达的患者生存和复发时间显著缩短（<0.005）。单因素和多因素COX回归分析表明，B7-H4是晚期肿瘤分期的独立预测因子。B7-H4单克隆抗体对抑制化疗耐药的TNBC细胞系具有潜在的抗增殖作用，并能增加TNBC细胞系对阿霉素、紫杉醇或卡铂的敏感性。RNA干扰介导的TNBC细胞中B7-H4沉默通过抑制PTEN/PI3K/AKT途径增强药物诱导的凋亡，而在B7-H4敲低和B7-H4低表达细胞中重新表达B7-H4会增加PI3K和AKT的磷酸化以及PETN表达的恢复。
我们的数据表明，B7-H4是TNBC患者预后不良的生物标志物，并且至少部分通过PTEN/PI3K/AKT途径在化疗耐药中下调。靶向B7-H4可能为TNBC患者提供一种有吸引力的治疗方法。
