Development of Dual-Target Small Molecules for Cancer Therapy: Biological Evaluation of CDC25-HDAC Inhibitors and Synthetic Exploration of EZH2-Based Compounds.

Cancer continues to pose a major clinical challenge due to its heterogeneity, recurrence, and therapeutic resistance. Dual-target inhibitors that simultaneously disrupt complementary oncogenic pathways have emerged as a promising strategy to enhance efficacy and overcome resistance. This thesis explores the rational design, synthesis, and evaluation of such small molecules, with emphasis on targeting aggressive cancers including triple-negative breast cancer (TNBC) and glioblastoma (GBM).
In the first part of this work, dual CDC25–HDAC inhibitors were developed and evaluated in TNBC models. One compound displayed potent anti-tumor activity, effectively inhibiting both CDC25 and HDAC enzymes. Mechanistic studies revealed suppression of CDK1 dephosphorylation, induction of DNA damage, arrest of cell cycle progression at the S and G2/M phases, and apoptosis, while sparing non-malignant cells. These results established the therapeutic relevance of CDC25–HDAC dual inhibition in TNBC.
Subsequent investigations extended this series to GBM, where a lead compound demonstrated superior potency, exerting strong cytotoxic effects in both parental and temozolomide-resistant GBM cells. In vivo, the compound prolonged survival in an orthotopic GBM mouse model with favorable safety outcomes. Transcriptomic analysis revealed marked downregulation of cell cycle checkpoint and mitosis-associated genes, particularly members of the chromosomal passenger complex, whose high expression in GBM patients correlates with poor prognosis. Protein-level validation confirmed disruption of this complex, leading to defective mitosis and reduced tumor proliferation.
In addition to these biological studies, two series of EZH2-based dual inhibitors were designed and synthesized by integrating EZH2-targeting pharmacophores with Linezolid and Imiquimod scaffolds, respectively. Both series were successfully synthesized and characterized, thereby expanding the chemical space of EZH2 dual inhibitors and establishing a foundation for future pharmacological evaluation.
Collectively, this thesis underscores the potential of dual inhibition strategies in addressing aggressive cancers. The CDC25–HDAC series yielded promising therapeutic candidates with validated activity in TNBC and GBM, while the EZH2-based hybrids contribute new chemical entities for future translational research. Together, these findings highlight the value of rational dual-target design in advancing anticancer drug discovery.