ABSTRACT
Objective@#To explore the expression of FAT1 in esophageal squamous cell carcinoma (ESCC) tissues, and its effect on cell proliferation.@*Methods@#The expression levels of FAT1 protein in human ESCC tissues and matched adjacent normal tissues were determined by immunohistochemistry (IHC). Lentivirus based knockdown of FAT1 was carried out in YSE2 and Colo680N cell lines and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assays was performed to examine the effect of FAT1 on the proliferation of these ESCC cells. Colony formation assay was used to detect the colony formation ability. Flow cytometry was performed to analyze the cell cycle and apoptosis. The expression levels of cell cycle markers in FAT1 knock out ESCC cell lines were detected by real-time quantitative reverse transcription polymerase chain reaction(qRT-PCR) and Western blot.@*Results@#The relative expression of FAT1 in ESCC tissues was 66.97±21.53, significantly lower than 78.13±16.76 of adjacent normal tissues(P<0.05). Knockdown of FAT1 promoted cell proliferation and colony formation. In YSE2 cell, the division time in negative control (NC) group was (1 570±51) min, significantly longer than (1 356±31) min in shFAT1 group. In Colo680N cell, division time in NC group was (1 532±53) min, significantly longer than (1 290±30) min in shFAT1 group (P<0.05). Knockdown of FAT1 promoted G1-to S-phase transition and resulted in the upregulation of CDK4/CDK6/CCND1.@*Conclusion@#FAT1 inhibits the proliferation and G1-to S-phase transition of ESCC cells through regulating the protein expression of CDK4/CDK6/CCND1 complex.
ABSTRACT
Objective:To analyze the expression of LETM2 in KYSE150 and ECA109 cell lines and its effect on the proliferation, migra-tion, and invasion of esophageal squamous cell carcinoma (ESCC). Methods:The expression level of the LETM2 protein in 90 paired hu-man ESCC tissues and matched adjacent normal tissues was determined through immunohistochemistry. The expression level of LETM2 in ESCC cell lines was detected by real-time PCR and Western blot. The expression levels of LETM2 in KYSE150 and ECA109 cell lines were knocked down using lentivirus. MTT assays were performed to examine the effect of LETM2 on the proliferation of ESCC cells. Colony formation assay was used to detect the colony formation ability. Flow cytometry was performed to analyze the cell cycle. The effect of LETM2 depletion on the migration and invasion of ESCC cells was determined by Transwell assay. Results:LETM2 expres-sion was frequently upregulated in the ESCC tissues than in the adjacent normal tissues. The suppressed exogenous expression of LETM2 led to the inhibition of cell proliferation and colony formation. However, cell migration and invasion were not affected. The re-sults on the cell cycle distribution revealed that LETM2 knockdown acts as a negative regulator of the cell cycle at the G1 to S phase transition. Conclusion:LETM2 acts as a tumor-driven gene in the development and progression of ESCC. This finding suggests that LETM2 can be used as an efficient prognosis biomarker and a potential therapeutic target for ESCC.