In vivo manipulation of the protein homeostasis network in rhabdomyosarcoma (IMAGE)
Caption
Figure 1: p97 inhibition activates the unfolded protein response and induces apoptosis in rhabdomyosarcoma. (A) RMS13 cells were treated with DMSO or 10 micromolar MAL3-101 for 9 hours, and total RNA was extracted and subjected to whole transcriptome sequencing. Differentially expressed genes (log2 fold-change ≥1 or ≤−1), treated with MAL3-101 compared to DMSO were uploaded to SigCom LINCS to identify genetic perturbations in a panel of cell lines with matching transcriptional effects. (B) The top 50 such genetic perturbations showed that loss of VCP, encoding the ATPase p97, resulted in similar transcriptomes in 8 cell lines. (C) Immunoblots from RMS13 cells treated with the p97 inhibitors CB-5083 and UPCDC-30766 or the HSP70 inhibitor MAL3-101 show similar kinetics of UPR activation. Phosphorylated, active PERK demonstrates a slower migration and upward shift. (D) The effects of these compounds on the transcription of UPR targets, as measured by qPCR for spliced XBP1 (XBP1(s)), ATF4, and DDIT3 (p-value by one-way ANOVA = 0.0015, 0.3551, and 0.0076 respectively; p-values by Dunnett’s post-hoc multiple comparisons test are shown, *p < 0.05, **p < 0.01, ***p < 0.001, Abbreviation: ns: not significant). (E) Four patient-derived rhabdomyosarcoma cell lines were treated with increasing doses of CB-5083 and viability analyzed by CellTiterGlo. EC50 doses are in the sub-micromolar range.
Credit
Copyright: © 2025 Kwong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Usage Restrictions
With credit to the original source.
License
Original content