Balcioglu Ozlen, Heinz Richard E, Freeman David W, Gates Brooke L, Hagos Berhane M, Booker Evan, Mirzaei Mehrabad Elnaz, Diesen Hyrum T, Bhakta Kishan, Ranganathan Supraja, Kachi Masami, Leblanc Mathias, Gray Peter C, Spike Benjamin T
Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112, USA.
Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA.
Breast Cancer Res. 2020 Nov 13;22(1):125. doi: 10.1186/s13058-020-01361-z.
CRIPTO is a multi-functional signaling protein that promotes stemness and oncogenesis. We previously developed a CRIPTO antagonist, ALK4-Fc, and showed that it causes loss of the stem cell phenotype in normal mammary epithelia suggesting it may similarly inhibit CRIPTO-dependent plasticity in breast cancer cells.
We focused on two triple negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) to measure the effects of ALK4-Fc on cancer cell behavior under nutrient deprivation and endoplasmic reticulum stress. We characterized the proliferation and migration of these cells in vitro using time-lapse microscopy and characterized stress-dependent changes in the levels and distribution of CRIPTO signaling mediators and cancer stem cell markers. We also assessed the effects of ALK4-Fc on proliferation, EMT, and stem cell markers in vivo as well as on tumor growth and metastasis using inducible lentiviral delivery or systemic administration of purified ALK4-Fc, which represents a candidate therapeutic approach.
ALK4-Fc inhibited adaptive responses of breast cancer cells under conditions of nutrient and ER stress and reduced their proliferation, migration, clonogenicity, and expression of EMT and cancer stem cell markers. ALK4-Fc also inhibited proliferation of human breast cancer cells in stressed tumor microenvironments in xenografts and reduced both primary tumor size and metastatic burden.
Cancer cell adaptation to stresses such as nutrient deprivation, hypoxia, and chemotherapy can critically contribute to dormancy, metastasis, therapy resistance, and recurrence. Identifying mechanisms that govern cellular adaptation, plasticity, and the emergence of stem-like cancer cells may be key to effective anticancer therapies. Results presented here indicate that targeting CRIPTO with ALK4-Fc may have potential as such a therapy since it inhibits breast cancer cell adaptation to microenvironmental challenges and associated stem-like and EMT phenotypes.
CRIPTO是一种多功能信号蛋白，可促进干性和肿瘤发生。我们之前开发了一种CRIPTO拮抗剂ALK4-Fc，并表明它会导致正常乳腺上皮细胞中干细胞表型的丧失，这表明它可能同样抑制乳腺癌细胞中依赖CRIPTO的可塑性。
我们聚焦于两种三阴性乳腺癌细胞系（MDA-MB-231和MDA-MB-468），以测量ALK4-Fc在营养剥夺和内质网应激条件下对癌细胞行为的影响。我们使用延时显微镜在体外对这些细胞的增殖和迁移进行了表征，并对CRIPTO信号介质和癌症干细胞标志物的水平及分布的应激依赖性变化进行了表征。我们还使用可诱导的慢病毒递送或纯化的ALK4-Fc的全身给药评估了ALK4-Fc在体内对增殖、上皮-间质转化（EMT）和干细胞标志物以及肿瘤生长和转移的影响，这代表了一种候选治疗方法。
ALK4-Fc在营养和内质网应激条件下抑制了乳腺癌细胞的适应性反应，并降低了它们的增殖、迁移、克隆形成能力以及EMT和癌症干细胞标志物的表达。ALK4-Fc还抑制了异种移植中应激肿瘤微环境中人类乳腺癌细胞的增殖，并减小了原发性肿瘤大小和转移负担。
癌细胞对营养剥夺、缺氧和化疗等应激的适应可能对休眠、转移、治疗抗性和复发起关键作用。确定控制细胞适应、可塑性以及类干细胞样癌细胞出现的机制可能是有效抗癌治疗的关键。此处呈现的结果表明，用ALK4-Fc靶向CRIPTO可能具有作为此类治疗的潜力，因为它抑制乳腺癌细胞对微环境挑战以及相关的类干细胞样和EMT表型的适应。
