Expression of complement C3 in serums and tissues of lung adenocarcinoma patients with brain metastases and mechanism of complement C3 in inducing epithelial mesenchymal transition
10.3760/cma.j.cn115355-20240107-00016
- VernacularTitle:肺腺癌脑转移患者血清和组织中补体C3的表达及其诱导上皮间质转化的机制研究
- Author:
Wenwen YUE
1
;
Weiwei SHAO
;
Chen ZHANG
;
Xichao DAI
;
Jun YUAN
;
Weigang BIAN
Author Information
1. 徐州医科大学盐城临床学院 盐城市第一人民医院肿瘤科，盐城 224001
- Keywords:
Lung neoplasms;
Brain metastasis;
Adenocarcinoma;
Neoplasm metastasis;
Complement C3;
Epithelial-mesenchymal transition
- From:
Cancer Research and Clinic
2024;36(10):721-727
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the expression of complement C3 in serums and tissues of lung adenocarcinoma patients with brain metastases and the mechanism of complement C3 in inducing epithelial mesenchymal transition (EMT).Methods:The retrospective case-control study, cell experiments and animal experiments were conducted. The serum samples from 20 healthy examinees, 20 advanced lung adenocarcinoma patients without brain metastases and 20 advanced lung adenocarcinoma patients with brain metastases at the First People's Hospital of Yancheng from January 2021 to January 2023 were collected, and the expression of complement C3 in serum samples was detected by immunoturbidimetry. At the same time, lung tissue samples were collected from 10 lung adenocarcinoma patients without brain metastases, and lung tissue and brain tissue samples were collected from 10 lung adenocarcinoma patients with brain metastases in the First People's Hospital of Yancheng. Immunohistochemistry was used to detect the expression of complement C3, C3aR, Kruppel like factor 5 (KLF5), and N-cadherin (N-cad) in the tissue samples. Using lentivirus to construct a human lung adenocarcinoma with brain metastases cell line PC14-C3 with stable overexpression of complement C3, with cells infected with empty vector virus as the control group (PC14-Ctrl). Western blotting was used to detect the expression of complement C3, KLF5, N-cad, and E-cadherin (E-cad) in PC14-C3 and PC14-Ctrl cells, and scratch assay was used to assess cell migration ability. Using the random number table method, 12 BALB/c nude mice were evenly divided into PC14-C3 group and PC14-Ctrl group. PC14-C3 cells and PC14-Ctrl cells were subcutaneously inoculated on the ventral side, and the body mass and tumor volume of the nude mice were recorded. Real-time fluorescence quantitative polymerase chain reaction was used to detect the expression of KLF5, N-cad and E-cad mRNA in various tumor cells and tumor tissues of nude mice.Results:The serum complement C3 levels in healthy individuals, lung adenocarcinoma patients without brain metastases and lung adenocarcinoma patients with brain metastases were (1.14±0.17) g/L, (1.20±0.15) g/L and (1.61±0.21) g/L, respectively. The serum complement C3 level in lung adenocarcinoma patients with brain metastases was higher than that in lung adenocarcinoma patients without brain metastases and healthy individuals, and the differences were statistically significant (both P < 0.001). The results of immunohistochemical testing showed that the proportions of positive expression areas of complement C3, C3aR, KLF5, and N-cad proteins in the lung primary lesions of lung adenocarcinoma patients with brain metastases were higher than those of patients without brain metastases, and the differences were statistically significant (all P < 0.05). The mRNA ( P < 0.05) and protein expression levels of complement C3 in PC14-C3 cells were higher than those in PC14-Ctrl cells, indicating successful transfection. The scratch assay results showed that the migration rate of PC14-Ctrl cells was (37.5±4.1)%, and the migration rate of PC14-C3 cells was (60.4±2.9)%, and the difference was statistically significant ( t = 7.86, P < 0.01). The relative expressions of EMT promoting molecules KLF5 and N-cad mRNA in PC14-C3 cells were higher than those in PC14-Ctrl cells, while the relative expression of EMT inhibiting molecule E-Cad mRNA was lower than that in PC14-Ctrl cells, and the differences were statistically significant (all P < 0.05). On the 26th day of tumor loading, the tumor volume of nude mice in PC14-C3 group was (610±10) mm 3, while that of PC14-Ctrl group was (321±30) mm 3; the body mass of nude mice in PC14-C3 group was lower than that in PC14-Ctrl group [(21.6±0.6) g vs. (23.2±0.6) g], and the differences were statistically significant (both P < 0.05). At the end of the experiment, 5 nude mice died and 1 survived in the PC14-C3 group; 1 nude mouse died and 5 survived in the PC14-Ctrl group. The relative expressions of KLF5 and N-cad mRNA in the tumor tissues of nude mice in PC14-C3 group were higher than those in PC14-Ctrl group, while the relative expression of E-Cad mRNA was lower than that in PC14-Ctrl group, and the differences were statistically significant (all P < 0.05). Conclusions:Lung adenocarcinoma patients with brain metastases have high levels of complement C3 in their serums and primary lesions. Complement C3 may induce EMT and promote the occurrence of lung adenocarcinoma brain metastases by affecting the expressions of KLF5, N-cad and E-cad.
