Zhongguo aizheng zazhi (Feb 2022)
Expression, prognostic value of CBX3 in lung adenocarcinoma and its effect on biological behavior of cancer cells
Abstract
Background and purpose: Chromobox 3 (CBX3), an important component of chromatin, is involved in the development and progression of various cancers. However, the expression and role of CBX3 in lung adenocarcinoma are still unclear. This study aimed to investigate the relationship between the expression of CBX3 in lung adenocarcinoma and prognosis of lung adenocarcinoma, and to study the effects of CBX3 on proliferation, migration and invasion of A549 lung adenocarcinoma cells. Methods: Transcriptome data of lung adenocarcinoma and corresponding clinical data were downloaded from the Cancer Genome Atlas (TCGA), and R software was used to analyze the expression difference of CBX3 and the correlation of immune infiltration in lung adenocarcinoma. The prognostic significance of CBX3 in lung adenocarcinoma was analyzed by receiver operating characteristic (ROC) curve and Kaplan-Meier analysis. Twenty lung adenocarcinoma samples from patients (with informed consent obtained) who underwent palliative or radical lung cancer resection from August 2020 to January 2021 were collected from the intelligent Biobank of Peking University Shenzhen Hospital at -80 ℃. Real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) was used to verify the expression of CBX3 in 20 frozen lung adenocarcinoma tissue samples and paired normal lung tissues. A549 cells were transfected with small interfering RNA (siRNA) to silence the expression of CBX3, and A549 cells were divided into silent group (si-CBX3 group) and negative control group (si-NC group) according to the type of siRNA transfection. The effects of CBX3 on proliferation, migration and invasion of A549 cells were investigated by cell counting kit-8 (CCK-8) assay, clone formation assay, scratch assay and transwell assay, respectively. Results: The difference analysis based on TCGA lung adenocarcinoma data and RTFQ-PCR results of lung adenocarcinoma samples showed that CBX3 was significantly overexpressed in lung adenocarcinoma (P<0.05). The infiltration of T helper 2 (Th2) cells was positively correlated with the expression of CBX3 [correlation coefficient (r)=0.437], while mast cells (r=-0.444), eosinophils (r=-0.380) and other immune cells were negatively correlated with the expression of CBX3. The area under ROC curve (AUC) value was 0.912, indicating that CBX3 has a good diagnostic value for lung adenocarcinoma. Kaplan-Meier analysis showed that the survival period of the group with high expression of CBX3 was shorter, suggesting a poor prognosis. After the expression of CBX3 was silenced in A549 cells, significantly decreased proliferation ability of A549 cells was detected by CCK-8 and clone formation assays (P<0.01). The results of scratch assay showed that the mobility of A549 cells was (22.68±3.44)% after silencing, which was significantly lower compared with the control group (P<0.05). Transwell assay results showed that the relative invasion rate of A549 cells was (53.94±5.39)%, and the invasion ability was significantly decreased (P<0.01). Conclusion: CBX3 is significantly overexpressed in lung adenocarcinoma, which predicts poor prognosis of lung adenocarcinoma and can be used as a prognostic marker of lung adenocarcinoma, and the high expression of CBX3 promotes the proliferation, migration and invasion of A549 cells.
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