# A novel TAp73‐inhibitory compound counteracts stemness features of glioblastoma stem cells

## TL;DR

A new compound that inhibits TAp73 reduces stem cell features in glioblastoma, suggesting a potential new treatment approach.

## Contribution

A novel natural compound that represses TAp73 is identified as a potential therapy for glioblastoma stem cells.

## Key findings

- TAp73 is essential for maintaining stemness in glioblastoma stem cells.
- The TAp73-inhibitory compound BMT9 reduces stem cell invasion and stemness features.
- TAp73 may sustain tumor progression by regulating neurodevelopmental programs.

## Abstract

Glioblastoma (GB) is the most common and fatal type of primary malignant brain tumor for which effective therapeutics are still lacking. GB stem cells, with tumor‐initiating and self‐renewal capacity, are mostly responsible for GB malignancy, representing a crucial target for therapies. The TP73 gene, which is highly expressed in GB, gives rise to the TAp73 isoform, a pleiotropic protein that regulates neural stem cell biology; however, its role in cancer has been highly controversial. We inactivated TP73 in human GB stem cells and revealed that TAp73 is required for their stemness potential, acting as a regulator of the transcriptional stemness signatures, highlighting TAp73 as a possible therapeutic target. As proof of concept, we identified a novel natural compound with TAp73‐inhibitory capacity, which was highly effective against GB stem cells. The treatment reduced GB stem cell‐invasion capacity and stem features, at least in part by TAp73 repression. Our data are consistent with a novel paradigm in which hijacking of p73‐regulated neurodevelopmental programs, including neural stemness, might sustain tumor progression, pointing out TAp73 as a therapeutic strategy for GB.

In glioblastoma (GB) tumors, a dynamic population of cancer stem cells (CSCs) drives tumor initiation, resistance, and recurrence. In this work, we demonstrated that TAp73 is crucial to sustain CSC features. We identified a TAp73‐repressive natural compound (BMT9) that impairs key GB stem cell properties. Together, our results postulate TP73 as an interesting therapeutic target, particularly in advanced tumor stages.