Role of TNFRSF12A in cell proliferation, apoptosis, and proinflammatory cytokine expression by regulating the MAPK and NF-κB pathways in thyroid cancer cells

Tumor necrosis factor receptor superfamily member 12A (TNFRSF12A) has been reported to be upregulated in thyroid cancer (THCA). However, the role and mechanism of TNFRSF12A in THCA remain largely unknown. TNFRSF12A expression in THCA samples was analyzed using bioinformatics analysis. CCK-8, EdU incorporation assay, TUNEL, and caspase-3 activity assay was used to detect cell proliferation and apoptosis in THCA cells. Correlated genes of TNFRSF12A were identified using LinkedOmics database and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Western blot analysis was performed to determine proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1), Bax, and Bcl-2 expression and to analyze the effect of TNFRSF12A on mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-κB) pathways. Results showed that TNFRSF12A was increased in THCA tissue samples and cells. KEGG analysis showed that correlated genes of TNFRSF12A were significantly enriched in MAPK and NF-κB signaling pathways. Moreover, TNFRSF12A knockdown inactivated the MAPK and NF-κB signaling pathways in THCA cells. TNFRSF12A silencing alone or combined with inhibitor of ERK (PD98059), JNK (SP600125), p38 (SB203580), or NF-κB (Bay 11-7082) impeded cell proliferation and reduced PCNA and CCND1 expression in THCA cells. Meanwhile, TNFRSF12A knockdown alone or combined with PD98059, SP600125, SB203580, or Bay 11-7082 facilitated cell apoptosis, increased caspase-3 activity, downregulated Bcl-2 expression, and upregulated Bax expression in THCA cells. TNFRSF12A knockdown alone or combined with PD98059, SP600125, SB203580, or Bay 11-7082 also decreased the expression levels of proinflammatory cytokines IL-1β, IL-6, and IL-8 in THCA cells. On the contrary, TNFRSF12A overexpression showed an opposite effect. Treatment with PD98059, SP600125, SB203580, or Bay 11-7082 reversed the effects of TNFRSF12A overexpression on cell proliferation, apoptosis, and proinflammatory cytokine expression. In conclusion, the effects of TNFRSF12A on proliferation, apoptosis, and proinflammatory cytokine expression in THCA cells were regulated by the MAPK and NF-κB pathways.