Sanguinarine impedes metastasis and causes inversion of epithelial to mesenchymal transition in breast cancer

A large number of breast cancer patients perishes due to metastasis instead of primary tumor, but molecular mechanisms contributing towards cancer metastasis remain poorly understood. Therefore, prompting development of novel treatment is inevitable. A vast variety of plant derived natural substance possesses several therapeutically active constituents, e.g. alkaloids, flavonoids, tannins, resins, terpenoids etc. that exhibit various pharmacological properties e.g. anti-inflammatory, anti-microbial and anti-cancer properties. Sanguinarine (SAN) alkaloid found its place among such naturally occurring substances that exerts several pharmacological activities, including anti-cancer effects. Until now, role of SAN not only against epithelial-mesenchymal transition (EMT) but also against metastasis progression in breast cancer remains indistinct. Thus, aim of the present study was to investigate effects of SAN on EMT process and cancer metastasis in animal model. MTT assay was performed to assess SAN effects on proliferation in breast cancer. Scratch assay was performed to evaluate effects of SAN on migration in breast cancer. Colony formation assay was performed to determine effects of SAN on colonization characteristics of breast cancer. Western blotting was performed to measure EMT regulating protein expression as well as major pathway protein expression induced against TGF-β treatment in breast cancer. Tail vein method of injecting breast cancer cells in bulb/c mice was conducted to study metastasis progression and thereafter assessing effects of SAN against metastasis in mice. In vivo results: MTT assay performed, demonstrated dose dependent inhibition of cell proliferation in breast cancer. Scratch assay results showed, SAN played a major role as migration inhibitor in estrogen receptor positive (ER+) breast cancer. Colony forming assay results demonstrated that SAN constrains ability of breast cancer to develop into well-defined colonies. Western blotting results for EMT regulating protein expression, after TGF-β treatment showed, SAN inhibited cadherin switch in ER+ breast cancer. Moreover, expression of pathway proteins involved in EMT process after TGF-β treatment i.e. Smad, PI3K/Akt and MAP kinase were significantly masked against SAN treatment. The appearance of metastatic nodules in lung tissues of mice model, helps to study the effects of SAN against metastasis in bulb/c mice. The obtained results have confirmed that SAN impeded lung metastasis. The macroscopic examination has confirmed metastasis inhibitory role of SAN in breast cancer. The Hematoxylin and eosin (H&E) staining results further advocate anti-metastatic characteristics of SAN, presented by fewer metastatic nodule and lesions appearance in SAN treated mice compared to untreated metastasis mice. In summary, SAN displayed prominent anti-metastatic effects in animal model and anti-proliferation effects together with significant inhibitory potential on EMT regulating protein expression against TGF-β treatment in ER+ breast cancer. So, overall findings of our study highlighted the pre-clinical significance of SAN in animal model therefore, further studies in humans as a part of clinical trial will be needed to establish pharmacokinetics and other effects of SAN, so that it can be a potential candidate for future treatment of metastatic breast cancer (MBC).