Gassner Tamara, Chittilappilly Christina, Pirich Theo, Neuditschko Benjamin, Hackner Klaus, Lind Judith, Aksoy Osman, Graichen Uwe, Klee Sascha, Herzog Franz, Wiesner Christoph, Errhalt Peter, Pecherstorfer Martin, Podar Klaus, Vallet Sonia
Department of Basic and Translational Oncology and Hematology, Division of Molecular Oncology and Hematology, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria.
Institute Krems Bioanalytics, IMC University of Applied Sciences, Krems an der Donau, Austria.
J Immunother Cancer. 2024 May 3;12(5):e008669. doi: 10.1136/jitc-2023-008669.
Skeletal morbidity in patients with cancer has a major impact on the quality of life, and preserving bone health while improving outcomes is an important goal of modern antitumor treatment strategies. Despite their widespread use in early disease stages, the effects of immune checkpoint inhibitors (ICIs) on the skeleton are still poorly defined. Here, we initiated a comprehensive investigation of the impact of ICIs on bone health by longitudinal assessment of bone turnover markers in patients with cancer and by validation in a novel bioengineered 3D model of bone remodeling.
An exploratory longitudinal study was conducted to assess erum markers of bone resorption (C-terminal telopeptide, CTX) and formation (procollagen type I N-terminal propeptide, PINP, and osteocalcin, OCN) before each ICI application (programmed cell death 1 (PD1) inhibitor or programmed death-ligand 1 (PD-L1) inhibitor) for 6 months or until disease progression in patients with advanced cancer and no evidence of bone metastases. To validate the in vivo results, we evaluated osteoclast (OC) and osteoblast (OB) differentiation on treatment with ICIs. In addition, their effect on bone remodeling was assessed by immunohistochemistry, confocal microscopy, and proteomics analysis in a dynamic 3D bone model.
During the first month of treatment, CTX levels decreased sharply but transiently. In contrast, we observed a delayed increase of serum levels of PINP and OCN after 4 months of therapy. In vitro, ICIs impaired the maturation of preosteoclasts by inhibiting STAT3/NFATc1 signaling but not JNK, ERK, and AKT while lacking any direct effect on osteogenesis. However, using our bioengineered 3D bone model, which enables the simultaneous differentiation of OB and OC precursor cells, we confirmed the uncoupling of the OC/OB activity on exposure to ICIs by demonstrating impaired OC maturation along with increased OB differentiation.
Our study indicates that the inhibition of the PD1/PD-L1 signaling axis interferes with bone turnover and may exert a protective effect on bone by indirectly promoting osteogenesis.
癌症患者的骨骼病变对生活质量有重大影响，在改善治疗结果的同时保持骨骼健康是现代抗肿瘤治疗策略的一个重要目标。尽管免疫检查点抑制剂（ICI）在疾病早期阶段广泛应用，但其对骨骼的影响仍不明确。在此，我们通过对癌症患者骨转换标志物的纵向评估以及在新型生物工程三维骨重塑模型中的验证，对ICI对骨骼健康的影响展开了全面调查。
开展一项探索性纵向研究，在每次应用ICI（程序性细胞死亡蛋白1（PD1）抑制剂或程序性死亡配体1（PD-L1）抑制剂）前，评估晚期癌症且无骨转移证据患者的骨吸收血清标志物（C端肽，CTX）和骨形成血清标志物（I型前胶原N端前肽，PINP，以及骨钙素，OCN），持续6个月或直至疾病进展。为验证体内结果，我们评估了ICI治疗时破骨细胞（OC）和成骨细胞（OB）的分化。此外，通过免疫组织化学、共聚焦显微镜检查和蛋白质组学分析，在动态三维骨模型中评估了它们对骨重塑的影响。
在治疗的第一个月，CTX水平急剧但短暂下降。相比之下，我们观察到治疗4个月后PINP和OCN血清水平延迟升高。在体外，ICI通过抑制STAT3/NFATc1信号通路而非JNK、ERK和AKT来损害前破骨细胞的成熟，同时对成骨没有任何直接影响。然而，使用我们的生物工程三维骨模型，该模型能够同时分化OB和OC前体细胞，我们通过证明OC成熟受损以及OB分化增加，证实了暴露于ICI时OC/OB活性的解偶联。
我们的研究表明，PD1/PD-L1信号轴的抑制会干扰骨转换，并可能通过间接促进成骨作用对骨骼发挥保护作用。
