[Proteins in cancer multidrug resistance]

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Multidrug resistance (MDR) is a major challenge in cancer chemotherapy, characterized by cancer cells' insensitivity to structurally unrelated drugs with different molecular targets.
• Various cellular mechanisms contribute to MDR, with proteins playing a pivotal role in mediating resistance.
• Key proteins involved include membrane transporters (P-gp, MRP1, BCRP, LRP), detoxification enzymes (GSTP-1), altered drug targets (TopoIIa), and apoptosis regulators (MT, CK18).

Purpose of the Study:

• To review the current understanding of key proteins responsible for MDR in cancer cells.
• To elucidate the molecular mechanisms underlying the action of these MDR-associated proteins.
• To highlight the challenges and limitations in developing clinical strategies to overcome MDR.

Main Methods:

• Literature review of current research on MDR mechanisms in cancer.
• Analysis of the roles of specific protein families, including ABC transporters, glutathione S-transferases, topoisomerases, metallothioneins, and cytokeratins.
• Examination of strategies aimed at inhibiting these proteins to overcome drug resistance.

Main Results:

• Membrane transporters like P-gp, MRP1, BCRP, and LRP reduce intracellular drug concentrations.
• Glutathione S-transferase P1 (GSTP-1) enhances drug detoxification.
• Altered topoisomerase II alpha (TopoIIa) and dysregulated apoptosis (via MT and CK18) contribute to resistance.
• Current therapeutic strategies targeting these proteins have limited clinical success.

Conclusions:

• Proteins involved in drug transport, detoxification, target modification, and apoptosis regulation are central to cancer MDR.
• Despite identified mechanisms, clinical strategies to overcome MDR remain largely ineffective, contributing to increased patient mortality.
• Further research into novel therapeutic targets and combination therapies is essential to combat MDR and improve cancer treatment outcomes.