Eng Zing Hong, Abdul Aziz Azlina, Ng Khoon Leong, Mat Junit Sarni
Department of Molecular Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
Department of Surgery, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
Front Mol Biosci. 2023 Aug 24;10:1237548. doi: 10.3389/fmolb.2023.1237548. eCollection 2023.
Papillary thyroid cancer (PTC) accounts for approximately 80% of all thyroid cancer cases. The mechanism of PTC tumourigenesis is not fully understood, but oxidative imbalance is thought to play a role. To gain further insight, this study evaluated antioxidant status, DNA repair capacity and genetic alterations in individuals diagnosed with benign thyroid lesion in one lobe (BTG) and PTC lesion in another. Individuals with coexisting BTG and PTC lesions in their thyroid lobes were included in this study. Reactive oxygen species (ROS) level, ABTS radical scavenging activity, ferric reducing antioxidant capacity, glutathione peroxidase and superoxide dismutase activities were measured in the thyroid tissue lysate. The expression of selected genes and proteins associated with oxidative stress defence and DNA repair were analysed through quantitative real-time PCR and Western blotting. Molecular alterations in genomic DNA were analysed through whole-exome sequencing and the potentially pathogenic driver genes filtered through Cancer-Related Analysis of Variants Toolkit (CRAVAT) analysis were subjected to pathway enrichment analysis using Metascape. Significantly higher ROS level was detected in the PTC compared to the BTG lesions. The PTC lesions had significantly higher expression of , and but significantly lower expression of and genes than the BTG lesions. Pathway enrichment analysis identified "regulation of MAPK cascade," "positive regulation of ERK1 and ERK2 cascade" and "negative regulation of reactive oxygen species metabolic process" to be significantly enriched in the PTC lesions only. Four pathogenic genetic variants were identified in the PTC lesions; , -rs2145142862, -rs372013175 and NM_001291737.1:p.Gln23fs while and were among 11 genes that were mutated in both BTG and PTC lesions. Our findings provided further insight into the connection between oxidative stress, DNA damage, and genetic changes associated with BTG-to-PTC transformation. The increased oxidative DNA damage due to the heightened ROS levels could have heralded the BTG-to-PTC transformation, potentially through mutations in the genes involved in the MAPK signalling pathway and stress-activated MAPK/JNK cascade. Further functional analyses and studies involving a larger sample size would need to be carried out to validate the findings from this pilot study.
甲状腺乳头状癌（PTC）约占所有甲状腺癌病例的80%。PTC的肿瘤发生机制尚未完全明确，但氧化失衡被认为在其中发挥作用。为了深入了解，本研究评估了一侧叶诊断为良性甲状腺病变（BTG）而另一侧叶为PTC病变的个体的抗氧化状态、DNA修复能力和基因改变。甲状腺叶中同时存在BTG和PTC病变的个体被纳入本研究。在甲状腺组织裂解物中测量活性氧（ROS）水平、ABTS自由基清除活性、铁还原抗氧化能力、谷胱甘肽过氧化物酶和超氧化物歧化酶活性。通过定量实时PCR和蛋白质印迹分析与氧化应激防御和DNA修复相关的选定基因和蛋白质的表达。通过全外显子测序分析基因组DNA中的分子改变，并使用Metascape对通过癌症相关变异分析工具包（CRAVAT）分析筛选出的潜在致病驱动基因进行通路富集分析。与BTG病变相比，PTC中检测到的ROS水平显著更高。与BTG病变相比，PTC病变中 、 和 的表达显著更高，但 和 基因的表达显著更低。通路富集分析确定“MAPK级联反应的调节”、“ERK1和ERK2级联反应的正调节”和“活性氧代谢过程的负调节”仅在PTC病变中显著富集。在PTC病变中鉴定出四个致病基因变异； 、-rs2145142862、-rs372013175和NM_001291737.1:p.Gln23fs，而 和 是在BTG和PTC病变中均发生突变的11个基因之一。我们的研究结果进一步深入了解了氧化应激、DNA损伤以及与BTG向PTC转变相关的基因变化之间的联系。由于ROS水平升高导致的氧化DNA损伤增加可能预示着BTG向PTC的转变，可能是通过参与MAPK信号通路和应激激活的MAPK/JNK级联反应的基因突变。需要进行进一步的功能分析和涉及更大样本量的研究来验证这项初步研究的结果。
