Targeting of Ubiquitin E3 Ligase RNF5 as a Novel Therapeutic Strategy in Neuroectodermal Tumors

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• RNF5, an endoplasmic reticulum (ER) E3 ubiquitin ligase, is involved in ER-associated protein degradation and maintaining protein homeostasis.
• RNF5 exhibits context-dependent pro- or anti-tumor activity in various cancer models.
• Its role in neuroectodermal tumors like neuroblastoma and melanoma remains controversial.

Purpose of the Study:

• To clarify the role of RNF5 in neuroblastoma and melanoma.
• To investigate the therapeutic potential of Analog-1, a pharmacological RNF5 activator, in these cancers.

Main Methods:

• Analysis of RNF5 gene expression in publicly available datasets of primary neuroblastoma and melanoma tumors.
• In vitro studies using neuroblastoma and melanoma cell lines treated with Analog-1.
• In vivo studies using neuroblastoma and melanoma xenograft mouse models treated with Analog-1.

Main Results:

• High RNF5 gene expression correlated with a better prognostic outcome in both neuroblastoma and melanoma patients.
• Analog-1 treatment reduced cell viability in vitro by inhibiting F1Fo ATP-synthase, impairing glutamine availability and energy metabolism, leading to oxidative stress and cell death.
• Analog-1 treatment significantly delayed tumor growth in vivo in both neuroblastoma and melanoma models.

Conclusions:

• RNF5 plays a protective role in neuroblastoma and melanoma, with higher expression linked to better patient prognosis.
• Analog-1 demonstrates significant anti-tumor efficacy in preclinical models of neuroblastoma and melanoma by targeting cellular metabolism.
• RNF5 is validated as an innovative drug target, and Analog-1 warrants further clinical development for these pediatric and adult neuroectodermal tumors.