Anticancer research

Tunicamycin induces paraptosis potentiated by inhibition of BRAFV600E in FRO anaplastic thyroid carcinoma cells.

PMID 25202067


The aim of the present study was to elucidate whether tunicamycin (TM) induces paraptosis as a cell death subroutine in anaplastic thyroid carcinoma (ATC) cells. 8505C, CAL62 and FRO cells were used. After treatment of TM, cell survival and morphology were investigated. The effect of the BRAF(V600E) inhibitor PLX4032 in combination with TM was evaluated. In FRO cells, TM induced paraptosis characteristic of cytoplasmic vacuolation and endoplasmic reticulum (ER) swelling, which was not associated with caspase activation and ER stress. TM-induced paraptosis was ameliorated by pre-treatment with the translation inhibitor cycloheximide, while it was accelerated by pre-treatment with the proteasome inhibitor MG132. PLX4032 augmented TM-induced paraptosis. TM induces paraptosis relevant to de novo protein synthesis and proteasomal activity, and inhibition of BRAF(V600E) potentiates TM-induced paraptosis in FRO cells harboring BRAF(V600E).