Multidrug resistance mechanisms influencing paclitaxel response

Multidrug resistance (MDR) mechanisms influencing paclitaxel response refer to the complex array of cellular adaptations that limit the efficacy of paclitaxel in cancer treatment. A primary driver of this resistance is the overexpression of the ABCB1 transporter (P-glycoprotein), which facilitates the ATP-dependent efflux of paclitaxel from the cytoplasm, thereby preventing it from reaching therapeutic concentrations (Gottesman et al., 2002). Furthermore, structural alterations in the target protein, beta-tubulin, including specific mutations or the overexpression of the TUBB3 isotype, can significantly reduce the drug's binding affinity and its ability to stabilize microtubules (Kavallaris, 2010). Resistance is also mediated by the dysregulation of apoptotic signaling molecules, such as the Bcl-2 family, and changes in the expression of microtubule-associated proteins like MAP4 and stathmin, which modulate microtubule dynamics (Orr et al., 2003). Additionally, variations in the metabolic clearance of paclitaxel by hepatic enzymes, specifically CYP2C8 and CYP3A4, contribute to inter-individual differences in drug response and resistance (Baker et al., 2002). These mechanisms collectively present a major challenge in oncology, necessitating the development of P-gp inhibitors and microtubule-stabilizing agents that are not substrates for these resistance pathways (Alzahrani et al., 2022).

Other names

Paclitaxel resistanceTaxane resistanceMDR in paclitaxel therapyChemoresistance to paclitaxel

Paclitaxel binds to the beta-subunit of tubulin, stabilizing microtubules and inducing cell cycle arrest; resistance mechanisms counteract this by effluxing the drug or altering the tubulin target.