Research Progress of the Molecular Mechanism of Antithyroid Cancer Activity of Shikonin.

Thyroid cancer is one of the most common endocrine neoplasms. Treatment methods include surgical resection, radioactive iodine therapy, inhibition of thyroid-stimulating hormone, and inhibition of kinase-based target therapies. These treatments induced adverse effects. Lithospermum officinale possesses antioxidant, anticancer, burn-healing, and anti-inflammatory activities, and Shikonin is the main ingredient. Antithyroid cancer studies of Shikonin discovered that it inhibited thyroid cancer cell migration and invasion by suppressing the epithelial-mesenchymal transition; induced cell cycle arrest; induced DNA damage and apoptosis by producing excessive reactive oxygen species; upregulated Bax; increased the stability of p53; decreased the expression of Mdm2; downregulated Slug and MMP-2, MMP-9, and MMP-14; repressed the phosphorylation of Erk and Akt; activated the p16/retinoblastoma protein pathway, leading to apoptosis; suppressed the expression of DNMT1; reduced the PTEN gene methylation; increased the expression of PTEN, leading to the inhibition of migration; increased LC3-II to induce autophagy and apoptosis of medullary thyroid carcinoma; and upregulated βII-tubulin in the cell to produce less resistance to cisplatin and paclitaxel, without cross-resistance to other anticancer agents. In vivo studies showed that it is safe in Sprague-Dawley rats, Beagle dogs, and nude mice.