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Objective:To investigate the expressions of eukaryotic initiation factor-4B (eIF4B) and eukaryotic initiation factor-5A (eIF5A) in papillary thyroid carcinoma tissues, and to analyze their regulatory effects on cell proliferation in vitro.Methods:The clinical data of 61 patients diagnosed with papillary thyroid carcinoma who received surgical resection at Yuncheng Central Hospital from January 2020 to October 2021 were retrospectively analyzed. The postoperative tumor tissues and paracancerous normal thyroid tissues (>1 cm from the margin of the mass) were retained. Immunohistochemistry was used to detect the expressions of eIF4B, eIF5A and proliferating cell nuclear antigen (PCNA) in different tissues. The correlation of eIF4B, eIF5A expressions with the clinicopathological characteristics of patients, and the relationship between eIF4B, eIF5A and PCNA were analyzed. The thyroid cancer cell line SW1736 and normal thyroid cell line HT-ori3 were selected. The expressions of eIF4B mRNA and eIF5A mRNA were detected by using real-ime quantitative polymerase chain reaction (qRT-PCR). After the small interfering RNA (siRNA) of siRNA-eIF4B and siRNA-eIF5A were synthesized, the interfering plasmids were constructed, and SW1736 cells were transfected, siRNA-eIF4B group and siRNA-eIF5A group were obtained; the empty plasmid transfection group and the blank control group without transfection intervention were established. The cell proliferation activity was detected by using CCK-8 assay, and the expression of PCNA mRNA was detected by using qRT-PCR.Results:The positive rates of eIF4B and eIF5A in papillary thyroid cancer tissues were higher than those in paracancerous normal thyroid tissues [65.57% (40/61) vs. 29.51% (18/61), 57.38% (35/61) vs. 9.84% (6/61), P < 0.001]. The positive rates of eIF4B and eIF5A were statistically different in patients with different tumor diameter [>3 cm vs. ≤3 cm: 88.89% (16/18) vs. 55.81% (24/43),77.78% (14/18) vs. 48.84% (21/43), all P < 0.05], lymph node metastasis [with vs. without: 85.00% (17/20) vs. 56.10% (23/41), 80.00% (16/20) vs. 46.34% (19/41), all P < 0.05] and the number of different nodes [multiple vs. single: 86.67% (13/15) vs. 58.70% (27/46), 86.67% (13/15) vs. 47.83% (22/46), all P < 0.05]; there were no statistically significant differences in the positive rates of eIF4B and eIF5A among patients with different age and gender (all P > 0.05). Positive correlation was found between eIF4B score and the positive cell proportion of PCNA ( r = 0.66, P = 0.0324), eIF5A score and the positive cell proportion of PCNA ( r = 0.62, P = 0.024), eIF4B score and eIF5A score ( r = 0.63, P = 0.021). The expression levels of eIF4B mRNA and eIF5A mRNA in thyroid cancer cell line SW1736 cell was higher than that of HT-ori3 cell in normal thyroid (all P < 0.05). The cell proliferation activity of SW1736 and PCNA mRNA expression level in siRNA-eIF4B group and siRNA-eIF5A group were lower than those in the empty vector transfected group and the blank control group (all P < 0.05). Conclusions:eIF4B and eIF5A are expressed elevated in papillary thyroid carcinoma, and both are involved in tumor development and progression. The role of eIF4B and eIF5A may be related to promoting the proliferation of tumor cells.
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0.05).Conclusion CO2-independent culture cell system is parallel to CO2-dependent culture cell system in their effects on cell proliferation and gene expression.