Although various pharmacological activities of the shikonins have been documented, understanding of the hierarchical regulation of these diverse and integrated bio-activities at the genome level is still lacking. In this study, through cross-examination between transcriptome and microRNA array analyses, we predicted that topical treatment of mouse skin tissues in vivo affects epithelial-mesenchymal transition (EMT) and the expression of related microRNAs, including 200a, 200b, 200c, 141, 205 and 429 microRNAs. In situ immunohistological analyses on test skin tissues demonstrated that specific EMT regulatory molecules are involved in the effect on shikonin-treated epidermal tissues. RT-PCR analyses subsequently confirmed the downregulating effects of shikonin on expression of microRNA 205 and members of the microRNA 200 family, which are known as key regulators of the EMT process. Expression of two RNA targets of the microRNA 200 family in EMT regulation, namely Sip1 (Zeb2) and Tcf8 (Zeb1), were consistently upregulated by shikonin treatment. These results suggest that topical treatment with shikonin can confer a potent stimulatory effect on EMT and suppress the expression of the associated microRNAs in vivo in skin tissues. The cellular and molecular evidence presented here supports our previous findings on the specific pharmacological effects of shikonin in wound-healing and immune-modulation.
