TGFB1-TGF-β/Smad信号在甲状腺乳头状癌侵袭相关表型中的表达特征

Expression characteristics of TGFB1-TGF-β/Smad signaling in invasion-related phenotypes of papillary thyroid carcinoma

摘要:

目的 探讨TGFB1-TGF-β/Smad信号在甲状腺乳头状癌(PTC)中的表达特征。方法 收集31例PTC患者的癌组织及配对癌旁组织，采用实时荧光定量PCR(qPCR)检测TGFB1 mRNA表达水平，采用Western blot分析TGF-β1蛋白整体表达情况，并通过免疫组化结合QuPath软件对TGF-β1及其下游分子p-Smad2/3的组织定位及表达强度进行定量分析。根据术后病理结果进行腺外侵犯(ETE)及淋巴结转移(LNM)分层，并在癌组织-癌旁组织配对基础上分别进行分层内配对比较及分层间组间比较。结果 qPCR结果显示，TGFB1 mRNA在PTC肿瘤组织中的表达显著高于配对癌旁组织(P<0.05)，该差异在ETE及LNM各分层内均可重复，但分层组间(No-ETE vs. ETE 和 N0 vs. N1)比较差异无统计学意义(P>0.05)。Western blot结果显示，TGF-β1蛋白整体表达水平在癌与癌旁组织间差异无统计学意义(P>0.05)，提示其蛋白表达与mRNA水平存在不一致性。免疫组化结果显示，TGF-β1主要定位于癌组织细胞胞浆，其表达水平在癌组织中显著高于癌旁组织(P<0.05)，在ETE及LNM各分层内均呈相似趋势。p-Smad2/3在癌组织中呈明显核定位增强，提示TGF-β/Smad信号通路在肿瘤层面处于激活状态。进一步分层分析发现，p-Smad2/3核定位增强现象在No-ETE分层中表现更明显，在N0分层中亦呈相似趋势，而在ETE及N1样本内，该差异趋于减弱或表现不稳定；分层组间比较差异无统计学意义(P>0.05)。结论 PTC组织中TGFB1转录水平升高，TGF-β1表达增强，p-Smad2/3核定位状态在不同侵袭相关分层中呈现差异性变化，提示TGF-β/Smad信号在PTC侵袭过程中可能具有阶段相关的调控特征。

Abstract:

Objective To investigate the expression characteristics of TGFB1-TGF-β/Smad signaling in papillary thyroid carcinoma (PTC). Methods Cancer tissues and paired adjacent non-cancerous tissues were collected from 31 patients with PTC. The expression level of TGFB1 mRNA was detected using real-time fluorescence quantitative polymerase chain reaction (qPCR), and the overall expression of TGF-β1 protein was evaluated by Western blot. The tissue localization and expression intensity of TGF-β1 and its downstream molecule p-Smad2/3 were quantitatively analyzed by immunohistochemistry combined with QuPath software. Samples were stratified into extrathyroidal extension (ETE) and lymph node metastasis (LNM) groups according to the postoperative pathological results, and comparisons were conducted both within and between stratified groups based on the paired cancer tissue and adjacent non-cancerous tissue. Results The qPCR results indicated that the expression of TGFB1 mRNA in PTC cancer tissues was significantly higher than that in the paired adjacent tissues (P<0.05), and this difference was consistently observed within ETE and LNM subgroups, whereas no significant differences were found between stratified subgroups (No-ETE vs ETE and N0 vs N1) (P>0.05). Western blot analysis showed no statistically significant difference in the overall expression level of TGF-β1 protein between the cancer and adjacent tissues (P>0.05), suggesting a discrepancy between the protein expression and mRNA level. The immunohistochemical results revealed that TGF-β1 was mainly localized in the cytoplasm of cancer cells and was significantly elevated in cancer tissues compared with adjacent tissues (P<0.05), with a similar trend within each of the ETE and LNM subgroups. p-Smad2/3 showed a significantly enhanced nuclear localization in cancer tissues, indicating that the TGF-β/Smad signaling pathway was activated at the tumor level. Further subgroup analysis revealed that the enhanced nuclear localization of p-Smad2/3 was more pronounced in the No-ETE subgroup and showed a similar trend in the N0 subgroup, while in the ETE and N1 subgroups, this difference tended to weaken or become unstable; there was no statistically significant difference between the subgroups (P>0.05). Conclusions The transcriptional level of TGFB1 in PTC tissues is elevated, and the expression of TGF-β1 is enhanced. The nuclear localization status of p-Smad2/3 shows differential changes in different invasion-related stratifications, suggesting that the TGF-β/Smad signaling may have stage-related regulatory characteristics during the invasion process of PTC.