Baicalin from Chinese skullcap inhibits growth of squamous cell skin carcinoma

In this study, researchers from China investigated the cellular gene targets responsible for baicalin’s anti-tumor activity. The results of their functional and proteomic analysis were published in The American Journal of Chinese Medicine.

• There is abundant evidence of the key role ultraviolet radiation (UVR) plays in the development of skin cancer.
• The human skin, especially the epidermal layer, is the main defense against UV radiation.
• Baicalin is a major bioactive component of Scutellaria baicalensis (Chinese skullcap), a plant that exhibits anti-tumor activity. The mechanism behind its anticarcinogenic activity is not completely understood.
• Baicalin inhibited UVB-induced photo-damage and apoptosis in HaCaT cells (human skin keratinocytes) in a previous study done by the researchers.
• Here, they performed two-dimensional electrophoresis liquid chromatography-mass spectrometry/mass spectrometry (2-DE LC-MS/MS) with HaCaT cells following UVB and baicalin exposure. They also did 2-DE for protein separation, followed by matrix-assisted laser desorption/ionization mass spectrometry and database searches.
• They designed and synthesized nucleophosmin (NPM)-specific siRNA (small interfering RNA) and transfected it into skin squamous cancer A431 cells to knockdown NPM expression.
• They assessed proliferation and cell cycle status using CCK8 and flow cytometry, respectively.
• The researchers identified 38 protein spots that are differentially expressed in HaCaT cells exposed to baicalin and/or UVB irradiation.
• These proteins are involved in detoxification, proliferation, metabolism, cytoskeleton and motility.
• They also found several proteins that have been linked to tumor progression and resistance, such as NPM.
• Baicalin treatment reduced the cellular proliferation rate and induced arrest during the S-phase of the cell cycle in A431 cells.
• NPM1 silencing significantly enhanced the effect of baicalin.

Based on their results, the researchers concluded that baicalin exerted its antitumor activity by inhibiting tumor growth in the A431 cell line, and this inhibition may be associated with the regulation of NPM gene expression.

Journal Reference:

Li D, Lin B, Yusuf N, Burns EM, Yu X, Luo D, Min W. PROTEOMIC ANALYSIS AND FUNCTIONAL STUDIES OF BAICALIN ON PROTEINS ASSOCIATED WITH SKIN CANCER. The American Journal of Chinese Medicine. 2017;45(03):599–614. DOI: 10.1142/s0192415x17500355