Despite major therapeutic advances, triple-negative breast cancer (TNBC) still presents a worth prognosis than hormone receptors-positive breast cancers. One major issue relies in the molecular and mutational heterogeneity of TNBC subtypes that is reinforced by the absence of reliable tumor-antigen that could serve as a specific target to further promote efficient tumor cell recognition and depletion. CD160 is a receptor mainly expressed by NK lymphocytes and presenting two isoforms, namely the GPI-anchored form (CD160-GPI) and the transmembrane isoform (CD160-TM). While CD160-GPI is constitutively expressed on resting cells and involved in the generation of NK cells' cytotoxic activity, CD160-TM is neo-synthesized upon activation and promotes the amplification of NK cells' killing ability. CD160 expression was assessed by immunohistochemistry (IHC) and flow cytometry on TNBC patient biopsies or cell lines, respectively. Antibody (Ab)-mediated tumor depletion was tested in vitro by performing antibody-dependent cell cytotoxicity (ADCC) and phagocytosis (ADCP) assays, and in vivo on a TNBC mouse model. Preliminary data obtained by IHC on TNBC patients' tumor biopsies revealed an unconventional expression of CD160 by TNBC tumor cells. By using a specific but conformation-dependent anti-CD160-TM Ab, we established that CD160-TM, but not CD160-GPI, was expressed by TNBC tumor cells. A conformation-independent anti-CD160-TM mAb (22B12; muIgG2a isotype) was generated and selected according to pre-defined specificity and functional criterions. In vitro functional assays demonstrated that ADCC and ADCP could be induced in the presence of 22B12, resulting in TNBC cell line apoptosis. The ability of 22B12 to exert an in vivo anti-tumor activity was also demonstrated on a TNBC murine model. Our data identify CD160-TM as a tumor marker for TNBC and provide a rational for the use of anti-CD160-TM antibodies as therapeutic tools in this tumor context.

中文翻译：

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鉴定 CD160-TM 作为三阴性乳腺癌的肿瘤靶点：可能的治疗应用

尽管治疗取得了重大进展，但三阴性乳腺癌 (TNBC) 的预后仍优于激素受体阳性乳腺癌。一个主要问题在于 TNBC 亚型的分子和突变异质性，而这种异质性由于缺乏可靠的肿瘤抗原而得到加强，而可靠的肿瘤抗原可以作为进一步促进有效的肿瘤细胞识别和清除的特定靶点。 CD160是一种主要由NK淋巴细胞表达的受体，具有两种亚型，即GPI锚定型（CD160-GPI）和跨膜亚型（CD160-TM）。 CD160-GPI 在静息细胞上组成型表达并参与 NK 细胞细胞毒活性的产生，而 CD160-TM 是在激活后新合成的，并促进 NK 细胞杀伤能力的放大。分别通过免疫组织化学 (IHC) 和流式细胞术对 TNBC 患者活检或细胞系评估 CD160 表达。通过抗体依赖性细胞毒性 (ADCC) 和吞噬作用 (ADCP) 测定在体外测试抗体 (Ab) 介导的肿瘤耗竭，并在 TNBC 小鼠模型上进行体内测试。 IHC 对 TNBC 患者肿瘤活检获得的初步数据显示，TNBC 肿瘤细胞异常表达 CD160。通过使用特异性但构象依赖性的抗 CD160-TM Ab，我们确定 TNBC 肿瘤细胞表达 CD160-TM，而不是 CD160-GPI。根据预定义的特异性和功能标准生成和选择构象独立的抗 CD160-TM mAb（22B12；muIgG2a 同种型）。体外功能测定表明，22B12 存在时可诱导 ADCC 和 ADCP，导致 TNBC 细胞系凋亡。 22B12 发挥体内抗肿瘤活性的能力也在 TNBC 小鼠模型上得到了证明。我们的数据将 CD160-TM 确定为 TNBC 的肿瘤标志物，并为在这种肿瘤背景下使用抗 CD160-TM 抗体作为治疗工具提供了合理性。