Carew Jennifer S, Espitia Claudia M, Sureshkumar Sruthi, Carrera Espinoza Maria Janina, Gamble Madison E, Wang Wei, Lee Benjamin R, Nawrocki Steffan T
Department of Medicine, Division of Hematology and Oncology, University of Arizona Cancer Center, Tucson, AZ, USA.
Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA; Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA; Arizona Center for Drug Discovery, University of Arizona, Tucson, AZ, USA.
Cancer Lett. 2025 Mar 31;613:217496. doi: 10.1016/j.canlet.2025.217496. Epub 2025 Jan 30.
Repurposing FDA approved drugs with off-target autophagy inhibition such as chloroquine/hydroxychloroquine (CQ, HCQ) has produced modest anticancer activity in clinical trials, due in part, to a failure to define predictive biomarkers that enable the selection of patients that best respond to this treatment strategy. We identified a new role for REDD1 as a determinant of sensitivity to autophagy inhibition in renal cell carcinoma (RCC). RNA sequencing, qRT-PCR, immunoblotting, gene silencing, knockout and overexpression studies revealed that REDD1 expression is a key regulator of cell death stimulated by autophagy inhibitors. Comprehensive in vitro and in vivo studies were conducted to evaluate the selectivity, tolerability, and efficacy of the PIM kinase inhibitor TP-3654 and CQ in preclinical models of RCC. Markers of autophagy inhibition and cell death were evaluated in tumor specimens. Transcriptomic analyses identified REDD1 (DDIT4) as a highly induced gene in RCC cells treated with the PIM kinase inhibitor TP-3654. Focused studies confirmed that PIM1 inhibition was sufficient to induce REDD1 and stimulate autophagy through the AMPK cascade. DDIT4 knockout and overexpression studies established its mechanistic role as a regulator of sensitivity to autophagy inhibition. Inhibition of autophagy with CQ synergistically enhanced the in vitro and in vivo anticancer activity of TP-3654. Our findings identify REDD1 as a novel determinant of the sensitivity of RCC cells to autophagy inhibition and support further investigation of PIM kinase inhibition as a precision strategy to drive sensitivity to autophagy-targeted therapies through REDD1 upregulation.
重新利用美国食品药品监督管理局（FDA）批准的具有脱靶自噬抑制作用的药物，如氯喹/羟氯喹（CQ，HCQ），在临床试验中已产生了一定的抗癌活性，部分原因是未能确定预测性生物标志物，从而无法筛选出对该治疗策略反应最佳的患者。我们发现REDD1在肾细胞癌（RCC）中作为自噬抑制敏感性的决定因素具有新作用。RNA测序、qRT-PCR、免疫印迹、基因沉默、基因敲除和过表达研究表明，REDD1表达是自噬抑制剂刺激细胞死亡的关键调节因子。进行了全面的体外和体内研究，以评估PIM激酶抑制剂TP-3654和CQ在RCC临床前模型中的选择性、耐受性和疗效。在肿瘤标本中评估自噬抑制和细胞死亡的标志物。转录组分析确定REDD1（DDIT4）是在用PIM激酶抑制剂TP-3654处理的RCC细胞中高度诱导的基因。重点研究证实，抑制PIM1足以诱导REDD1并通过AMPK级联刺激自噬。DDIT4基因敲除和过表达研究确定了其作为自噬抑制敏感性调节因子的机制作用。用CQ抑制自噬可协同增强TP-3654的体外和体内抗癌活性。我们的研究结果确定REDD1是RCC细胞对自噬抑制敏感性的新决定因素，并支持进一步研究抑制PIM激酶作为一种精准策略，通过上调REDD1来提高对自噬靶向治疗的敏感性。
