14-3-3epsilon contributes to tumour suppression in laryngeal carcinoma by affecting apoptosis and invasion.
BACKGROUND
14-3-3epsilon regulates a wide range of biological processes, including cell cycle control, proliferation, and apoptosis, and plays a significant role in neurogenesis and the formation of malignant tumours. However, the exact function and regulatory mechanism of 14-3-3epsilon in carcinogenesis have not been elucidated.


METHODS
The expression of 14-3-3epsilon was assessed by RT-PCR and western blotting. The invasiveness and viability of Hep-2 cells were determined by the transwell migration assay and MTT assay, respectively. Cell cycle and apoptosis of Hep-2 cells were detected by flow cytometry.


RESULTS
The mRNA and protein expression of 14-3-3epsilon in larynx squamous cell carcinoma (LSCC) tissues were significantly lower than those in clear surgical margin tissues. Statistical analysis showed that the 14-3-3epsilon protein level in metastatic lymph nodes was lower than that in paired tumour tissues. In addition, the protein level of 14-3-3epsilon in stage III or IV tumours was significantly lower than that in stage I or II tumours. Compared with control Hep-2 cells, the percentages of viable cells in the 14-3-3epsilon-GFP and negative control GFP groups were 36.68 +/- 14.09% and 71.68 +/- 12.10%, respectively. The proportions of S phase were 22.47 +/- 3.36%, 28.17 +/- 3.97% and 46.15 +/- 6.82%, and the apoptotic sub-G1 populations were 1.23 +/- 1.02%, 2.92 +/- 1.59% and 13.72 +/- 3.89% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The percentages of the apoptotic cells were 0.84 +/- 0.25%, 1.08 +/- 0.24% and 2.93 +/- 0.13% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The numbers of cells that penetrated the filter membrane in the control, negative control GFP and 14-3-3epsilon-GFP groups were 20.65 +/- 1.94, 17.63 +/- 1.04 and 9.1 +/- 0.24, respectively, indicating significant differences among the different groups.


CONCLUSIONS
Decreased expression of 14-3-3epsilon in LSCC tissues contributes to the initiation and progression of LSCC. 14-3-3epsilon can promote apoptosis and inhibit the invasiveness of LSCC.
Che
Xing-Hua
XH
Department of Medical Genetics, China Medical University, Heping District, Shenyang, China.
Chen
Hong
H
Xu
Zhen-Ming
ZM
Shang
Chao
C
Sun
Kai-Lai
KL
Fu
Wei-Neng
WN
D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control* / Q000556:secondary; D045744:Cell Line, Tumor; D002465:Cell Movement; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase; D014162:Transfection
D048948:14-3-3 Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C482983:YWHAE protein, human