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AIMS: AHNAK2 may be used as a candidate marker for TC diagnosis and treatment. BACKGROUND: Thyroid cancer [TC] is the most frequent malignancy in endocrine carcinoma, and the incidence has been increasing for decades. OBJECTIVE: To understand the molecular mechanism of DTC, we performed next-generation sequencing [NGS] on 79 paired DTC tissues and normal thyroid tissues. The RNA-sequencing [RNA-seq] data analysis results indicated that AHNAK nucleoprotein 2 [AHNAK2] was significantly upregulated in the thyroid cancer patient's tissue. METHOD: We also analyzed AHNAK2 mRNA levels of DTC tissues and normal tissues from The Cancer Genome Atlas [TCGA]. The association between the expression level of AHNAK2 and clinicopathological features was evaluated in the TCGA cohort. Furthermore, AHNAK2 gene expression was analyzed by quantitative real-time polymerase chain reaction [qRT-PCR] in 40 paired DTC tissues and adjacent normal thyroid tissues. The receiver operating characteristic [ROC] curve was performed to evaluate the diagnostic value of AHNAK2. For cell experiments in vitro, AHNAK2 was knocked down using small interfering RNA [siRNA], and the biological function of AHNAK2 in TC cell lines was investigated. The expression of AHNAK2 was significantly upregulated in both the TCGA cohort and the local cohort. RESULT: The analysis results of the TCGA cohort indicated that the upregulation of AHNAK2 was associated with tumor size [P<0.001], lymph node metastasis [P<0.001], and disease stage [P<0.001]. The area under the curve [AUC] [TCGA: P<0.0001; local validated cohort: P<0.0001.] in the ROC curve revealed that AHNAK2 might be considered a diagnostic biomarker for TC. The knockdown of AHNAK2 reduced TC cell proliferation, colony formation, migration, invasion, cell cycle, and induced cell apoptosis. CONCLUSION: Furthermore, the protein levels of phospho-PI3 Kinase p85 and phospho-AKT were down-regulated in the transfected TC cell. Our study results indicate that AHNAK2 may promote metastasis and proliferation of thyroid cancer through PI3K/AKT signaling pathway. Thus, AHNAK2 may be used as a candidate marker for TC diagnosis and treatment.
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Background: Thyroid carcinoma (TC) is an increasingly common malignancy of endocrine organs, and its most frequently encountered histotype is papillary thyroid cancer (PTC). Identifying new potential gene alterations is important for completely elucidating the mechanism of PTC initiation and progression. Thus, we performed whole transcriptome sequence analysis (RNA-seq) on 79 PTC tissue samples and paired adjacent nontumor tissue samples to study the molecular mechanism of TC tumorigenesis and progression further. The results of RNA-seq analysis showed that spectrin beta, nonerythrocytic 2 (SPTBN2), was markedly overexpressed in PTC tissues relative to that in the paired nontumor tissues. Additionally, the analysis results for 502 PTC samples and 58 nontumor thyroid samples from The Cancer Genome Atlas dataset were consistent with our RNA-seq results. However, the molecular mechanisms and function of SPTBN2 in TC progression remain unknown. Methods: We examined SPTBN2 gene expression in 48 papillary thyroid tumor tissues and paired adjacent normal thyroid tissues by using qRT-PCR. SPTBN2 expression in the TC cell lines was silenced by small interfering RNA. Then, the transfected TC cells were used to investigate the in vitro function of SPTBN2. Result: The expression of SPTBN2 was significantly upregulated in our RNA-seq cohort, our local validated cohort, and TCGA RNA-seq cohort. The results of the in vitro experiment revealed that in TC cell lines, SPTBN2 downregulation considerably suppressed tumor cell proliferation, the cell cycle, migration, colony formation, and invasion and induced cell apoptosis. Furthermore, the protein levels of CCNE2, CDK2, CDK4, and Bcl-2 were downregulated, and those of P21, Bax, cleaved caspase-8, and cleaved caspase-3 had increased in transfected TC cells relative to in control TC cells. Conclusion: The downregulation of SPTBN2 caused apoptosis and retarded G1/S cell cycle transition in TC cells. Thus, SPTBN2 may be a good candidate gene for TC diagnosis and therapy.
