ACYP2 Induces Temozolomide Resistance in Glioblastoma by Promoting PARP1-Mediated DNA Damage Repair

Abstract Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with a poor prognosis. Temozolomide (TMZ) is the most widely used chemotherapeutic agent and can significantly improve patient survival rates. However, numerous patients develop TMZ resistance, leading to limited therapeutic benefits. Therefore, it is crucial to investigate the mechanisms of TMZ resistance in patients with GBM and identify the sensitizing targets of TMZ to improve its clinical efficacy. In this study, we demonstrated that acylphosphatase 2 (ACYP2) was involved in regulating the sensitivity of GBM to TMZ. ACYP2 knockdown significantly reduced the IC50 values of TMZ in GBM cells, whereas overexpression of ACYP2 increased their IC50 values. The combination of ACYP2 knockdown and TMZ treatment not only inhibited the malignant behavior of GBM cells in vitro but also slowed the progression of intracranial GBM in mice. Additionally, comet tail and γ-H2AX staining assays showed that ACYP2 knockdown enhanced the TMZ-induced DNA damage. Mechanistically, ACYP2 upregulates the transcription factor c-Myc to promote the transcription of its downstream target PARP1, an important regulatory molecule for DNA damage repair, ultimately inducing TMZ resistance in GBM cells. Thus, this study demonstrated that ACYP2 is a potential therapeutic target for TMZ-resistant patients with GBM. Implications: The ACYP2-driven c-Myc/PARP1 signaling axis defines a critical pathway driving TMZ resistance and represents a translationally actionable target for therapeutic intervention in GBM.