Investigating the impact of microgravity on thyroid cells is crucial for space travel readiness. Thyroid gland is one of the important endocrine organs to maintain the body homeostasis and associated with high frequent malignancy. This study aimed to find out the gene expression differences in five thyroid cell lines under between normal gravity and microgravity.

We cultured five types of thyroid cell lines (Nthy-ori 3-1, TPC-1, BAPAP, SNU-790 and SNU-80) under the normal gravity and microgravity, using clinostat, microgravity simulator. Five thyroid cancer cell lines underwent cDNA microarray analysis after 5 days. Differentially expressed genes (DEGs) were identified using Transcriptome Analysis Console, and Gene Set Enrichment Analysis (GSEA) was employed for pathway analysis.

Nthy-ori 3-1 (48), and SNU-80 (29). Among the cellular component gene ontology, DEGs were related with extracellular region and cell membrane in Nthy-ori 3-1, BCPAP and SNU-80; whereas nucleosome and DNA packing complex in SNU-790 and TPC-1. In the GSEA, carcinogenesis related pathways (Chemokine, JAK-STAT, MAPK, VEGF and WNT signaling) are enriched in all 5 micro-gravity cultured cells.

Microgravity induces differential expression in genes related to cellular membrane and nuclear packing, with enrichment of carcinogenesis related pathways. This suggests the need for thorough thyroid examinations during space habitation. Future research should extend to other organs and real microgravity conditions.