Glioblastoma (GBM) is an aggressive brain cancer that frequently returns after treatment, largely due to acquired resistance to standard chemotherapy such as temozolomide (TMZ). In this new study, researchers explore whether a targeted drug combination can disable tumor survival programs and improve the effectiveness of TMZ against resistant disease.
The team focused on CUDC-907, a dual inhibitor that combines PI3K and HDAC blockade. PI3K pathway activity can support growth and resistance, while HDAC inhibition can reshape gene expression and stress responses. Together, these actions were tested for their ability to slow GBM proliferation and weaken the mechanisms tumors use to withstand DNA damage.
In cultured GBM cells, the investigators used cell-cycle and apoptosis assays to track how CUDC-907 changes cellular fate. The results showed a pronounced arrest in the G0/G1 phase, consistent with impaired cell-cycle progression. Molecular profiling further supported this shift, revealing decreased levels of core cycle and oncogenic regulators, alongside increased activity of a checkpoint protein.
To connect these phenotypes to specific signaling and transcriptional outputs, the study measured key proteins including MYC and cyclin-dependent kinases such as CDK2 and CDK4. CUDC-907 reduced MYC-driven expression programs while increasing p21, a checkpoint mediator known to restrain cell-cycle advancement when stresses accumulate.
Beyond proliferation, the researchers evaluated tumor aggressiveness traits relevant to invasion. They reported that CUDC-907 reduced migration and invasion-associated markers, including N-Cadherin, MMP2, and vimentin—molecular changes that suggest a weakened metastatic phenotype.
The central translational question was whether CUDC-907 can sensitize GBM to TMZ. Across multiple experimental platforms, including organoid systems and orthotopic mouse models, the combination produced a synergistic anti-tumor effect rather than simply additive inhibition.
Mechanistically, TMZ normally kills cells by damaging DNA, but resistant GBM can repair that damage. Here, CUDC-907 intensified DNA double-strand break indicators and increased PARP1 cleavage, while broadly disrupting DNA repair responses. The study also highlighted alterations in JAK-STAT signaling, linking pathway modulation to impaired repair and heightened chemotherapy vulnerability.
Overall, the findings position CUDC-907 as a promising pharmacological strategy to counter TMZ resistance. By concurrently suppressing MYC-associated cell-cycle control and undermining DNA damage repair, the dual PI3K/HDAC approach may help convert resistant GBM into a more treatable state.
Subject of Research: Glioblastoma chemoresistance; targeted PI3K/HDAC inhibition; TMZ sensitization
Article Title: CUDC-907 inhibits glioblastoma and enhances glioblastoma sensitivity to temozolomide by inhibiting DNA damage repair
References: 10.1016/j.gendis.2025.101948
Image Credits: Credit: Chencheng Fang, Pan Gou, Dandan Zhang, Xuanxuan Wu, Xiao Li, Man Li, Lu Gan, Jinjin Luo, Hongjuan Cui, Man Xu, Ping Liang
Keywords: glioblastoma, CUDC-907, PI3K, HDAC, temozolomide, TMZ resistance, MYC, p21, DNA damage repair, γ-H2AX, PARP1, JAK-STAT, organoids, orthotopic mouse model
