Reframing cancer drug resistance: transporters, persister cells, senescence, and emerging therapeutic strategies.

Cancer drug resistance remains one of the greatest barriers to durable therapeutic success. Here, we reframe resistance as a dynamic landscape shaped by transporter‑mediated efflux, reversible drug‑tolerant persister states, and therapy‑induced senescence. This review highlights areas where our group has made substantial contributions, with a particular focus on our own experimental and conceptual advances. We show how P‑glycoprotein (P-gp) overexpression, traditionally viewed as an obstacle sustaining cancer multidrug resistance (MDR), creates exploitable metabolic vulnerabilities, enabling the development of MDR‑selective compounds. We demonstrate that persister cells rely on transient P‑gp-mediated detoxification, revealing a therapeutic window during drug‑free intervals. We further show that senescence is not a terminal fate but a relapse‑initiating state requiring targeted intervention. Finally, we illustrate how pharmacokinetics and dosing schedules can be harnessed to reshape tumor evolution, culminating in LiPyDau, a next‑generation liposomal anthracycline with durable activity against resistant tumors. Together, these insights outline a unified strategy for anticipating, intercepting, and ultimately overcoming cancer drug resistance.