Zeng Peng, Shen Duo, Shu Wenbin, Min Shudan, Shu Min, Yao Xijuan, Wang Yong, Chen Rong
Department of Oncology, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu, China.
Department of Gastroenterology, The Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu, China.
Front Oncol. 2023 Apr 14;13:1143266. doi: 10.3389/fonc.2023.1143266. eCollection 2023.
Hepatocellular carcinoma (HCC) has very poor prognosis due to its immunosuppressive properties. An effective measure to regulate tumor immunity is brachytherapy, which uses I seeds planted into tumor. T cell immune receptors with immunoglobulin and ITIM domains (TIGIT) is highly expressed in HCC. The TIGIT-targeted probe is expected to be an effective tool for indicating immunomodulation of I seed brachytherapy in HCC. In this study, We constructed a novel peptide targeting TIGIT to evaluate the immune regulation of I seed brachytherapy for HCC by near-infrared fluorescence (NIRF).
Expression of TIGIT by immunofluorescence (IF) and flow cytometry (FCM) in different part and different differentiated human liver cancer tissues was verified. An optical fluorescence probe (Po-12) containing a NIRF dye and TIGIT peptide was synthesized for evaluating the modulatory effect of I seed brachytherapy. Lymphocytes uptake by Po-12 were detected by FCM and confocal microscopy. The distribution and accumulation of Po-12 in vivo were explored by NIRF imaging in subcutaneous and orthotopic tumors. IHC and IF staining were used to verify the expression of TIGIT in the tumors.
TIGIT was highly expressed in HCC and increased with tumor differentiation. The dye-labeled peptide (Po-12) retained a stable binding affinity for the TIGIT protein . Accumulation of fluorescence intensity (FI) increased with time extended in subcutaneous H22 tumors, and the optimal point is 1 h. TIGIT was highly expressed on lymphocytes infiltrated in tumors and could be suppressed by I seed brachytherapy. Accumulation of Po-12-Cy5 was increased in tumor-bearing groups while declined in 125I radiation group.
肝细胞癌（HCC）因其免疫抑制特性，预后极差。调节肿瘤免疫的一种有效措施是近距离放射治疗，即把碘-125种子植入肿瘤。具有免疫球蛋白和免疫受体酪氨酸抑制基序结构域的T细胞免疫受体（TIGIT）在HCC中高表达。靶向TIGIT的探针有望成为一种有效的工具，用于指示碘-125种子近距离放射治疗对HCC的免疫调节作用。在本研究中，我们构建了一种靶向TIGIT的新型肽，以通过近红外荧光（NIRF）评估碘-125种子近距离放射治疗对HCC的免疫调节作用。
通过免疫荧光（IF）和流式细胞术（FCM）验证不同部位和不同分化程度的人肝癌组织中TIGIT的表达。合成了一种包含近红外荧光染料和TIGIT肽的光学荧光探针（Po-12），用于评估碘-125种子近距离放射治疗的调节作用。通过FCM和共聚焦显微镜检测Po-12对淋巴细胞的摄取。通过NIRF成像在皮下和原位肿瘤中探索Po-12在体内的分布和蓄积情况。采用免疫组化（IHC）和IF染色验证肿瘤中TIGIT的表达。
TIGIT在HCC中高表达，并随肿瘤分化程度增加而升高。染料标记的肽（Po-12）对TIGIT蛋白保持稳定的结合亲和力。皮下H22肿瘤中荧光强度（FI）的蓄积随时间延长而增加，最佳时间点为1小时。TIGIT在浸润肿瘤的淋巴细胞上高表达，并且可被碘-125种子近距离放射治疗抑制。荷瘤组中Po-12-Cy5的蓄积增加，而在碘-125放射组中则下降。
