Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA; Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA; Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN, USA; Division of Oral and Maxillofacial Pathology, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
Oral Oncol. 2023 Feb;137:106304. doi: 10.1016/j.oraloncology.2022.106304. Epub 2023 Jan 4.
In head and neck squamous cell carcinoma (HNSCC), poor prognosis and low survival rates are associated with downregulated calprotectin. Calprotectin (S100A8/A9) inhibits cancer cell migration and invasion and facilitates G2/M cell cycle arrest. We investigated whether S100A8/A9 regulates DNA damage responses (DDR) and apoptosis in HNSCC after chemoradiation.
Human HNSCC cases in TCGA were analyzed for relationships between S100A8/A9 and expression of apoptosis-related genes. Next, S100A8/A9-expressing and non-expressing carcinoma lines (two different lineages) were exposed to genotoxic agents and assessed for 53BP1 and γH2AX expression and percent of viable/dead cells. Finally, S100A8/A9-wild-type and S100A8/A9 C57BL/6j mice were treated with 4-NQO to induce oral dysplastic and carcinomatous lesions, which were compared for levels of 53BP1.
In S100A8/A9-high HNSCC tumors, apoptosis-related caspase family member genes were upregulated, whereas genes limiting apoptosis were significantly downregulated based on TCGA analyses. After X-irradiation or camptothecin treatment, S100A8/A9-expressing carcinoma cells (i.e., TR146 and KB-S100A8/A9) showed significantly higher 53BP1 and γH2AX expression, DNA fragmentation, proportions of dead cells, and greater sensitivity to cisplatin than wild-type KB or TR146-S100A8/A9-KD cells. Interestingly, KB-S100A8/A9 cells showed similar 53BP1 and γH2AX levels to S100A8/A9-negative KB and KB-EGFP cells. After 4-NQO treatment, 53BP1 expression in oral lesions was significantly greater in calprotectin than S100A8/A9 mice.
In HNSCC cells, intracellular calprotectin is strongly suggested to potentiate DDR and promote apoptosis in response to genotoxic agents. Hence, patients with S100A8/A9-high HNSCC may encounter more favorable outcomes because more tumor cells enter apoptosis with increased sensitivity to chemoradiation therapy.
在头颈部鳞状细胞癌（HNSCC）中，预后不良和生存率低与钙卫蛋白下调有关。钙卫蛋白（S100A8/A9）抑制癌细胞迁移和侵袭，并促进 G2/M 细胞周期阻滞。我们研究了 S100A8/A9 是否在 HNSCC 放化疗后调节 DNA 损伤反应（DDR）和细胞凋亡。
分析 TCGA 中的人类 HNSCC 病例，以研究 S100A8/A9 与细胞凋亡相关基因表达之间的关系。接下来，用致突变剂处理 S100A8/A9 表达和不表达的癌细胞系（两种不同谱系），并检测 53BP1 和 γH2AX 的表达以及存活/死亡细胞的百分比。最后，用 4-NQO 处理 S100A8/A9 野生型和 S100A8/A9 C57BL/6j 小鼠，诱导口腔发育不良和癌前病变，并比较 53BP1 的水平。
在 S100A8/A9 高表达的 HNSCC 肿瘤中，细胞凋亡相关的半胱天冬酶家族成员基因上调，而限制细胞凋亡的基因则根据 TCGA 分析显著下调。用 X 射线或喜树碱处理后，S100A8/A9 表达的癌细胞（即 TR146 和 KB-S100A8/A9）显示出明显更高的 53BP1 和 γH2AX 表达、DNA 片段化、死亡细胞比例和对顺铂的敏感性，而野生型 KB 或 TR146-S100A8/A9-KD 细胞则较低。有趣的是，KB-S100A8/A9 细胞的 53BP1 和 γH2AX 水平与 S100A8/A9 阴性 KB 和 KB-EGFP 细胞相似。用 4-NQO 处理后，钙卫蛋白组口腔病变中的 53BP1 表达明显高于 S100A8/A9 组。
在 HNSCC 细胞中，强烈提示细胞内钙卫蛋白增强了对致突变剂的 DDR，并促进了细胞凋亡。因此，S100A8/A9 高表达的 HNSCC 患者可能会有更好的预后，因为更多的肿瘤细胞进入凋亡，对放化疗的敏感性增加。
