Objective:To evaluate the effects of high mobility group protein box 1 (HMGB1) on clinical prognosis of esophagus squamous cell carcinoma (ESCC) patients treated with chemoradiotherapy and the radiosensitivity of xenograft in nude mice.Methods:A total of 90 endoscopic biopsy specimens were obtained from ESCC patients treated with chemoradiotherapy. The expression level of HMGB1 was determined by immunohistochemical staining. High expression level was defined when staining was observed on ≥50% of the tumor cells. All patients were divided into the high expression group ( n=48) and low expression group ( n=42), and their survival information was retrospectively analyzed. Cell transfection was performed with the plasmid carrying human HMGB1-shRNA to knockdown HMGB1 expression in ECA109 cells and xenograft mouse models were established. The tumor volume and mass were calculated after irradiation with a dose of 15 Gy. The cell apoptosis in xenograft tissues were detected. Survival analysis was performed using Kaplan-Meier method. Univariate prognostic analysis was conducted by log-rank test. Intergroup comparison was performed by analysis of variance (ANOVA). Results:The expression level of HMGB1 was significantly associated with gross tumor volume, longest diameter of tumor, T staging and distant metastasis ( χ2=9.663, 5.625, 4.068, 7.146, all P<0.05). In the low expression group, the overall survival (OS) ( χ2=4.826, P=0.028), progression-free survival (PFS) ( χ2=4.390, P=0.036) were longer compared with that in the high expression group. Further analysis of HMGB1-high expression patients showed that the radiation dose and the combination of chemoradiotherapy did not significantly affect the OS or PFS of ESCC patients. We observed that knockdown of HMGB1 slowed the growth rate of xenograft, decreased the tumor volume and increased the apoptosis rate after irradiation. Conclusions:ESCC patients with high expression level of HMGB1 obtain poor prognosis after chemoradiotherapy, which can be enhanced by increasing the sensitivity to radiotherapy and chemotherapy. HMGB1 knockdown can effectively increase the radiosensitivity of xenograft in ESCC nude mice.

Objective:To examine the effect of FAM83D knockdown on proliferation, survival ability and invasion of human esophageal squamous cell carcinoma after X-ray radiation, and explore the mechanism.Methods:The expression of FAM83D, E-cadherin and vimentin in tumor tissues was detected in 69 cases of esophageal squamous cell cancer by using immunohistochemical method. The siRNA based on the sequences of the FAM83D mRNA were synthesized to transfect into the cultured ECA109 cells as FAM83D shRNA group. The effect of silencing FAM83D gene was evaluated to determine the protein levels of FAM83D in the human oesophageal squamous cell carcinoma ECA109 and KYSE30 cells using western blotting. MTS, clone formation, and Transwell assay were employed to examine the proliferation, survival ability and invasion of ECA109 and KYSE30 cells in vitro, respectively. We used flow cytometry assay to analyze distribution of cell apoptosis in different groups. Western blotting was used to examine the expression of cell metastasis-related molecules and apoptosis-related protein. Results:The strong expression rates of FAM83D, E-cadherin, and vimentin were 55%(38/69), 36%(25/69) and 61%(42/69) in the tumor tissues, respectively. FAM83D protein expression was significantly and negatively correlated with the expression of E-cadherin ( r=-0.350, P<0.01), and positively with the expression of vimentin ( r=0.470, P<0.01). Western blotting results demonstrated that silencing FAM83D gene significantly reduced the FAM83D protein expression ( P<0.01). MTS data demonstrated that FAM83D knockdown after irradiation significantly inhibited the proliferation of esophageal squamous cell carcinoma ECA109 and KYSE30 cells ( P<0.05). The data from the clone formation assay revealed that the radiosensitivity was increased after downragulation of FAM83D expression ( P<0.01). In addition, the invasive abilities of oesophageal carcinoma cells transfected with FAM83D shRNA after irradiation were significantly inhibited compared with those of the NC group ( P<0.01), followed by the downregulation of N-cadherin, vimentin, Snail, p-Akt and p-GSK-3β expression, and the upregulation of E-cadherin expression ( P<0.01). The apoptosis rate of tumor cells in FAM83D shRNA group after irradiation was markedly increased ( P<0.01), followed by a decrease of Bcl-2 and Mcl-1 expression and an increase of Cleaved caspase-3 expression ( P<0.01). Conclusions:FAM83D expressions was found to be closely related to the invasion and development of ESCC. Furthermore, siRNA interference technology inhibited the expression of FAM83D gene in oesophageal squamous cell carcinoma cells, reduced the proliferation, invasion of cells, induced cell apoptosis, and increased radiosensitivity, which may be associated with regulating the epithelial-mesenchymaltransition via Snail/Akt/GSK-3β signaling pathways.

Objective: To evaluate the effect of X-ray radiation on cell proliferation, migration, survival ability and cell cycle of human esophageal squamous cell carcinoma after RNA interference-mediated down-regulation of HMGB1 gene expression. Methods: The expression of HMGB1 at mRNA and protein levels in the human esophageal squamous cell carcinoma cell lines ECA109 and KYSE30 was determined using RT-PCR and Western blot assays. MTS and Transwell assays were employed to examine the proliferation and migration of ECA109 and KYSE30 cell lines. The cellular survival ability in vitro was assessed by clone formation assay. The cell cycle after X-ray radiation in different groups was detected by flow cytometry. Results: The expression of HMGB1 at mRNA and protein levels in ECA109 and KYSE30 cells were markedly higher in a dose-dependent and time-dependent manner in the radiation group than that in the control group (all P<0.05). MTS results demonstrated that the proliferation of ECA109 and KYSE30 cells was obviously lower at each time point after radiation than that in the group without radiation (all P<0.01). The expression of HMGB1 at mRNA and protein levels was significantly inhibited in the HMGB1 siRNA group than those in the control and NC groups (both P<0.01). The data from the clone formation assay revealed that the radiosensitivity was significantly increased after down-regulation of HMGB1 expression (P<0.01). Transwell migration assay revealed that the number of migrating cells at the fourth hour after X-ray irradiation in the HMGB1 siRNA group was significantly lower than those in the control and negative groups (both P<0.01). In the HMGB1 siRNA group, the percentage of cells at G₀/G₁ phase was obviously higher, whereas the percentage of S phase was significantly lower than those in the control and NC groups, and the trend was even more significant after X-ray radiation (all P<0.01). Conclusion Inhibition of HMGB1 expression by siRNA can suppress the proliferation and migration of ECA109 and KYSE30 cells and enhance the radiosensitivity by increasing the cell cycle arrest at G₀/G₁ stage after X-ray irradiation in vitro.