Fig. 3.

Coadministration of miRNAs with chemotherapeutic agents may be more effective to control tumor progression. There is growing evidence supporting the feasibility of combination therapy. MicroRNAs downregulate the expression of efflux transporters in tumor cells, resulting in a higher level of intracellular drug accumulation and thus an improved efficacy (Zhu et al., 2008; Pan et al., 2009g, 2013; Liang et al., 2010; Shang et al., 2014; Li et al., 2015). In addition, miRNAs may directly target (proto-)oncogenes and thus additively or synergistically suppress tumor growth (Deng et al., 2014; Zhao et al., 2015).