Page 83 - 《中国药科大学学报》2025年第4期

第 56 卷第 4 期 於珈墨，等：胸腺五肽促进 T 细胞浸润抑制小鼠肝细胞癌皮下瘤生长的作用研究 479

100, 1000 ng/mL) for 72 hours. Cell viability was detected by sulforhodamine B (SRB) colorimetry. A
subcutaneous tumor model of liver cancer LM3 in immunocompromised mice was constructed, with three
randomly divided groups based on tumor volume: control group, TP5 group (20 mg/kg), and positive drug
Sorafinib group (30 mg/kg). The intervention effect of thymopentin on the growth of subcutaneous tumors in
immunocompromised mice was evaluated. Flow cytometry was used to analyze the changes in the proportion of
T cells and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment 11 days after TP5
administration in the Hepa1-6 model. MDSCs were cultured in vitro and treated with TP5. The effect of TP5 on
MDSCs was evaluated by detecting the levels of ROS, IL-6, and NO, which are effector molecules of MDSCs.
The mouse subcutaneous liver cancer model was established again using C57BL/6N mice. After 10 days, they
were randomly divided into four groups based on tumor volume: control group, low-dose TP5 group (10 mg/kg),
high-dose TP5 group (20 mg/kg), and arginine-deficient TP5 group (15 mg/kg). Drugs were administered
continuously for 11 days, and the intervention effect of arginine-deficient TP5 on tumor growth was evaluated
based on tumor weight. Annexin-V staining was used to detect the impact of TP5 on T cell survival. The results
showed that both low and high doses of TP5 inhibited the growth of subcutaneous liver cancer in
immunocompetent mice (P < 0.05), yet TP5 had no direct inhibitory effect on the proliferation of tumor cells
cultured in vitro. Besides, a high dose of TP5 could not inhibit the growth of subcutaneous liver cancer in
immunocompromised mice. Furthermore, TP5 promoted the infiltration of CD4 and CD8 T cells but decreased
MDSCs in the subcutaneous tumor microenvironment of immunocompetent mice. TP5 did not affect the levels of
ROS, IL-6, and NO in MDSCs. Lastly, arginine-deficient TP5 could not inhibit the growth of subcutaneous liver
cancer in immunocompetent mice. Accordingly, TP5 but not arginine-deficient TP5 promoted the increase in the
proportion of viable CD4 and CD8 T cells cultured in vitro. These results suggest that TP5 may inhibit the growth
of liver cancer by increasing T cell number in the liver cancer microenvironment.
Key words thymopentin; hepatocellular carcinoma; tumor microenvironment; arginine; T cells

肝细胞癌（hepatocellular carcinoma, HCC）是肝 抑制细胞（myeloid derived suppressor cells, MDSCs)、
癌的主要组织亚型，占原发性肝癌的 90%，是世界 调节性 T 细胞（Treg）、细胞毒性 T 淋巴细胞（cyto-
第三大肿瘤相关死亡的病因。中国 HCC 患者人数 toxic T lymphocyte, CTL）等。CTL 是杀伤肝癌细胞
占全球 50%，每年死亡人数 30 万~40 万，位居世界 的“主力军”，其浸润与患者预后密切相关 。目前
[3]
[1]
首位 。HCC 常起源于病毒性肝炎、非酒精性脂肪 研究发现，CTL 主要通过分泌Ⅱ型干扰素（interferon-
性肝炎（non-alcoholic steatohepatitis，NASH）等具有 gama, IFN-γ）促进肿瘤细胞抗原提呈，并通过分泌
慢性炎症的肝脏，因此其微环境非常复杂。HCC 起 颗粒酶 B、穿孔素和凋亡配体（Fas ligand, FasL）等
病隐匿，超过 70% 的患者确诊时已是晚期，限制了 效应分子直接杀伤肿瘤细胞。由于肝癌的免疫抑
手术、射频消融、肝移植等常规治疗方法的应用。 制微环境，肝癌微环境中的 CTL 细胞常表现出失能

HCC 同时是一种化疗难治性肿瘤，对大部分在其他 状态，主要抑制机制包括：（1）基质微环境限制
类型肿瘤中广泛使用的化疗药物耐受。血管新生 CTL 浸润，包括下调 T 细胞趋化因子及趋化因子受
是 HCC 的重要生物学特征，目前有多种血管生成 体，肝癌微环境基质细胞产生的物理屏障和异常的
抑制剂被批准用于 HCC 的一、二线治疗。然而，只 肿瘤脉管系统等；（2）肝癌微环境中的营养限制，如
有不到三分之一的患者从该治疗中受益，并且在开 葡萄糖、胆固醇及精氨酸等必需营养素的缺乏，对
始该方案的六个月内出现明显的耐药性，因此，这 T 细胞的功能和存活产生负面影响；（3）免疫抑制分
类药物只能在一定程度上改善患者的生存时间 。 子的高表达，如细胞间的信号延长、共抑制信号以
[2]
目前认为 HCC 治疗的长期疗效依赖于免疫系统的 及可溶性细胞因子的过量产生，如 IL-10、TGF-β
[4]
激活。 等，也可能导致 T 细胞的衰竭 。因此，寻找逆转
近年来，单细胞及空间转录组等技术的发展， T 细胞失能的药物是肝癌免疫治疗的一种重要策略。
极大地推动人类对肿瘤微环境特征的认识。肝脏 胸腺五肽（thymopentin, TP5）是由精氨酸、赖
是一个免疫特惠器官，具有特殊的免疫学特征，含 氨酸、天门冬氨酸、缬氨酸、酪氨酸五种氨基酸组
有大量的免疫细胞，包括库否细胞、骨髓来源免疫 成的多肽，其来源于胸腺激素中分离出来的单一多