背景:尽管他莫昔芬在治疗雌激素受体α(ERα)阳性乳腺癌方面取得了成功,随后的他莫昔芬耐药性的发展是临床上的共同挑战。催乳素受体(PRLR)下游信号可能与ERα在乳腺癌进展中协同作用。然而,针对PRL-PRLR轴联合他莫昔芬的潜在效应尚未得到彻底研究.
方法:从TCGA获得的高通量RNA-seq数据,分析了Metabric和GEO数据集,以探索乳腺癌细胞中PRLR的表达以及PRLR表达与他莫昔芬治疗的相关性。使用外源性或PRL过表达细胞模型来研究活化的PRLR途径在介导他莫昔芬不敏感性中的作用。免疫毒素靶向PRLR(N8-PE24)是用剪接-内皮素技术构建的,N8-PE24对乳腺癌的疗效进行了体外和体内评估,包括分析细胞生长或凋亡,3D球状体培养,和动物异种移植。
结果:PRL激活的PRLR通路可显著降低ERα阳性乳腺癌细胞对他莫昔芬的敏感性。他莫昔芬处理可上调PRLR的转录,并可通过碱化溶酶体诱导PRLR蛋白在乳腺癌细胞中的大量积累。同时,通过长期他莫昔芬压力获得的他莫昔芬抗性MCF7表现出PRLR转录和蛋白质水平的上调。免疫毒素N8-PE24在体外和体内均增强了乳腺癌细胞对他莫昔芬的敏感性。在异种移植模型中,当治疗PRLR阳性三阴性乳腺癌时,N8-PE24显著增强他莫昔芬和紫杉醇的疗效。
结论:PRL-PRLR轴可能与ERα阳性乳腺癌细胞中他莫昔芬不敏感相关。N8-PE24可以抑制乳腺癌细胞的生长,并提高PRLR阳性乳腺癌细胞对他莫昔芬和紫杉醇的药物敏感性。我们的研究为靶向PRLR治疗乳腺癌提供了新的视角。
BACKGROUND: Though
tamoxifen achieves success in treating estrogen receptor α (ERα)-positive breast cancer, the followed development of
tamoxifen resistance is a common challenge in clinic. Signals downstream of prolactin receptor (PRLR) could synergize with ERα in breast cancer progression. However, the potential effect of targeting PRL-PRLR axis combined with
tamoxifen has not been thoroughly investigated.
METHODS: High-throughput RNA-seq data obtained from TCGA, Metabric and GEO datasets were analyzed to explore PRLR expression in breast cancer cell and the association of PRLR expression with tamoxifen treatment. Exogenous or PRL overexpression cell models were employed to investigate the role of activated PRLR pathway in mediating tamoxifen insensitivity. Immunotoxin targeting PRLR (N8-PE24) was constructed with splicing-intein technique, and the efficacy of N8-PE24 against breast cancer was evaluated using in vitro and in vivo methods, including analysis of cells growth or apoptosis, 3D spheroids culture, and animal xenografts.
RESULTS: PRLR pathway activated by PRL could significantly decrease sensitivity of ERα-positive breast cancer cells to tamoxifen. Tamoxifen treatment upregulated transcription of PRLR and could induce significant accumulation of PRLR protein in breast cancer cells by alkalizing lysosomes. Meanwhile,
tamoxifen-resistant MCF7 achieved by long-term
tamoxifen pressure exhibited both upregulated transcription and protein level of PRLR. Immunotoxin N8-PE24 enhanced sensitivity of breast cancer cells to
tamoxifen both in vitro and in vivo. In xenograft models, N8-PE24 significantly enhanced the efficacy of tamoxifen and paclitaxel when treating PRLR-positive triple-negative breast cancer.
CONCLUSIONS: PRL-PRLR axis potentially associates with tamoxifen insensitivity in ERα-positive breast cancer cells. N8-PE24 could inhibit cell growth of the breast cancers and promote drug sensitivity of PRLR-positive breast cancer cells to tamoxifen and paclitaxel. Our study provides a new perspective for targeting PRLR to treat breast cancer.