The mechanism of epithelial-mesenchymal transition (EMT) consists of the cellular phenotypic transition from epithelial to mesenchymal status. The cells exhibiting EMT exist in cancer stem cell (CSC) population, which is involved in drug resistance. CSCs demonstrating EMT feature remain after cancer treatment, which leads to drug resistance, recurrence, metastasis and malignancy of cancer. In this context, the recent advance of nanotechnology in the medical application has ascended the possibility to target CSCs using nanomedicines. In this review article, we focused on the mechanism of CSCs and EMT, especially into the signaling pathways in EMT, regulation of EMT and CSCs by microRNAs and nanomedicine-based approaches to target CSCs.

While cancer remains the major cause of death worldwide, nanomaterial (NM)-based diagnosis and treatment modalities are showing remarkable potential to better tackle clinical oncology by effectively targeting therapeutic agents to tumors. NMs can selectively accumulate in solid tumors, and they can improve the bioavailability and reduce the toxicity of encapsulated cytotoxic agents. Additional noteworthy functions of NMs in cancer treatment include the delivery of contrast agents to image tumor sites, delivery of genetic materials for gene therapy, and co-delivery of multiple agents to achieve combination therapy or simultaneous diagnostic and therapeutic outcomes. Although several NM therapeutics have been successfully translated to clinical applications, the gap between the bench and the bedside remains ominously wide. Tumor heterogeneity and the disparity between pre-clinical and clinical studies have been identified as two of the major translational challenges of NM-based cancer therapies. Herein, we review a handful of recent research studies on the use of NMs in cancer therapy and imaging, with a limited discussion on the consequences of tumor heterogeneity and pre-clinical studies on translational research of NM-based delivery systems and propositions in the literature to overcome these challenges.