MicroRNAs are short non-coding RNAs that tune protein output by binding messenger RNAs and altering their stability or translation. Victor Ambros at University of Massachusetts Medical School first characterized microRNAs, establishing them as fundamental regulators of gene expression. Subsequent cancer research led by Carlo M. Croce at Ohio State University and George A. Calin at MD Anderson Cancer Center documented widespread microRNA dysregulation in tumors, linking these small RNAs to cell survival, proliferation, and therapy response. This foundational work underpins current understanding of how microRNAs contribute to anticancer drug resistance.
Mechanisms driving drug resistance
MicroRNAs can cause resistance by modulating multiple cellular pathways simultaneously. By downregulating tumor suppressors or upregulating survival factors, microRNAs alter apoptosis thresholds and reduce drug-induced cell death. They influence drug efflux through control of transporter expression, promoting reduced intracellular drug accumulation. MicroRNAs also affect DNA repair pathways and the epithelial-to-mesenchymal transition that supports invasive, therapy-resistant phenotypes. Because a single microRNA targets networks of messenger RNAs, its dysregulation produces complex, robust changes that conventional single-gene approaches may miss. This network effect helps explain why resistance often emerges despite initial tumor shrinkage.
Consequences for treatment and society
Clinically, microRNA-driven resistance complicates durable responses to chemotherapy, targeted agents, and immunotherapies. Research by Croce at Ohio State University and collaborators has shown that restoring or inhibiting specific microRNAs can reverse resistance in preclinical models, pointing to microRNA mimics and antagonists as therapeutic strategies under investigation. However, translating these approaches faces safety, delivery, and specificity challenges. Beyond biology, access to genomic and microRNA profiling is uneven across regions and health systems, meaning that potential predictive biomarkers may not benefit patients in low-resource settings. Environmental exposures and cultural factors that influence cancer incidence can also shape microRNA landscapes in populations, creating territorial differences in resistance mechanisms. Recognizing these social and ecological dimensions is essential for equitable implementation of microRNA-informed therapies.
Overall, microRNAs act as versatile modulators of anticancer drug resistance by rewiring gene networks that determine cell fate. Evidence from leading laboratories including Victor Ambros at University of Massachusetts Medical School, Carlo M. Croce at Ohio State University, and George A. Calin at MD Anderson Cancer Center supports their central role and motivates ongoing efforts to harness microRNAs for predictive diagnostics and targeted interventions.