Product Description

Etoposide hinders DNA repair, inhibits DNA replication, and induces cell death (apoptosis and autophagy) along with cell cycle arrest by reversibly inhibiting topoisomerase II. This reversible nature of its action suggests that prolonged administration may enhance its anti-tumor efficacy.

Screeningbio‘s Mia-pa-ca-2/Etoposide resistance cell line generated by exposing to increasing concentration of drug for certain period of time. After stable acquire resistance, cells were harvested and characterized for drug resistance by 7 days proliferation assay.

Data

Target Background

Etoposide (VP-16) is a widely used chemotherapeutic agent derived from podophyllotoxin that inhibits topoisomerase II by stabilizing the DNA–topoisomerase II complex, leading to DNA double‑strand breaks and subsequent cell cycle arrest (primarily in the G2/M phase) and apoptosis in rapidly dividing cancer cells. It is commonly employed in the treatment of small cell lung cancer, testicular carcinoma, lymphomas, and various pediatric malignancies. However, the development of drug resistance remains a major challenge limiting its long‑term efficacy.

Mechanistically, etoposide resistance arises through multiple cellular adaptations. Reduced expression or mutations of topoisomerase IIα (TOP2A) decrease drug binding and cleavage complex formation, while upregulation of efflux transporters such as P‑glycoprotein (MDR1/ABCB1) and multidrug resistance‑associated protein 1 (MRP1/ABCC1) reduces intracellular drug accumulation. Additionally, activation of survival pathways—including PI3K/Akt, MAPK, and NF‑κB signaling—promotes anti‑apoptotic responses. Enhanced DNA repair capacity (e.g., through ATM/ATR and homologous recombination), changes in apoptotic regulators (such as Bcl‑2 overexpression or p53 mutations), and increased autophagic flux or epithelial–mesenchymal transition (EMT) also contribute to reduced drug sensitivity.

Understanding these mechanisms is critical for designing strategies to overcome resistance, such as combination therapy with efflux transporter inhibitors (e.g., verapamil or zosuquidar), targeting compensatory signaling networks (e.g., PI3K/Akt or NF‑κB inhibitors), modulating autophagy or DNA repair pathways, or employing patient‑derived resistant cell models to guide personalized therapy development.