Effect Of PLOD2 On The Malignant Biological Behavior Of Oral Cancer

Objective:This study conducted experiments using bioinformatics data,oral cancer pathological tissue sections,and oral squamous cell carcinoma cells to investigate the expression of PLOD2 in oral cancer and its impact on the malignant biological behavior of oral cancer.Methods:Bioinformatics: The bioinformatics data of TCGA were analyzed using R language,and the differential genes related to Head and Neck Squamous Cell Carcinoma(HNSC)were screened,and the target genes were predicted by LASSO analysis and COX regression.Combined with clinicopathological features,target genes were analyzed.Histology:Pathological sections of 49 patients with oral cancer were collected from the Department of Pathology,Stomatology Hospital Affiliated to Nanjing Medical University from 2016 to 2020.The expression of PLOD2 in oral cancer tissues was detected by immunohistochemistry,and its clinical significance was analyzed combined with clinicopathological data.Cytology: The expressions of PLOD2 mRNA and protein in oral squamous cell cell lines HSC-2,HN4 and Human oral keratinocyte(HOK)were detected by quantitative real-time polymerase chain reaction(qRT-PCR)and western blot(WB)assay.PLOD2 lentivirus knockdown plasmid and no-load control plasmid were constructed and named as shRNA-PLOD2 and shRNA-NC,respectively.PLOD2 was knocked down in oral squamous cell cancer cell lines HSC-2 and HN4 with high expression of PLOD2,and transfection efficiency was observed by fluorescence inverted microscope.The knockdown effect was further determined by qRT-PCR and WB techniques.The effects of PLOD2 on the proliferation,colonization,migration and invasion of oral squamous cell carcinoma lines HSC-2 and HN4 were investigated in vitro.In this study,SPSS 26.0 was used for data analysis.The measurement data conforming to normal distribution were represented by mean plus or minus standard deviation.Independent sample t test was used for comparison between two groups,and one-way analysis of variance was used for comparison between multiple groups.Count data were represented by frequency(component ratio)[n(%)],and classification between groups was compared by 2 test or Fisher exact probability method.P<0.05 meant the difference was statistically significant(*P<0.05,**P<0.01).Results:Bioinformatics: The target gene PLOD2 was obtained by analyzing bioinformatics data,and PLOD2 was highly expressed in HNSCS by two online data analysis platforms simultaneously.The GEPIA data platform showed that PLOD2 expression was correlated with tumor stage and overall survival.TCGA data platform showed that PLOD2 expression was correlated with the differentiation degree of HNSC.Histology: Immunohistochemical results showed that the positive expression rate of PLOD2 in oral cancer was 76.2%,which was significantly higher than that in non-cancer tissues(14.3%,P<0.05),but there was no significant correlation between PLOD2 expression and clinicopathological features.Cytology:Cell experiments showed that the expression level of PLOD2 in oral squamous cell carcinoma lines HSC-2 and HN4 was significantly higher than that in oral normal keratinocyte HOK.Oral squamous cell carcinoma cell lines HSC-2 and HN4 successfully transformed lentivirus-knockout PLOD2 plasmid(shRNA-PLOD2),and shRNA-PLOD2 group significantly inhibited the migration and invasion of oral squamous cell carcinoma cell lines HSC-2 and HN4 in vitro compared with the knockout control group(shRNA-NC).Conclusion:PLOD2 has potential value in predicting the prognosis of oral cancer.PLOD2 knockdown can significantly inhibit the migration and invasion of oral cancer.