Li Na, Zhang Kun, Mu Xin, Tian Qiong, Liu Wenli, Gao Tianyuan, Ma Xiaona, Zhang Jian
Department of Dermatology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China.
Department of Ophthalmology and Cosmetic Plastic Surgery, The Second Affiliated Hospital of Xi'an Medical University, Xi'an 710004 Shaanxi, China.
Anticancer Agents Med Chem. 2018;18(7):1001-1008. doi: 10.2174/1871520618666171229190835.
Actinic Keratosis (AK), is the most common precancerous skin lesion induced by the excessive Ultraviolet B (UVB) and is a significant threat to the public health. UVB exposure causes oxidative DNA damage and is considered to be a significant contributor to AK and subsequent development of skin cancer. Besides, activation of p38 MAPK also plays a significant role in the development of AK.
This study aimed at the development of a nature compound which can inhibit UVB-induced AK.
MTS Cell Proliferation Assay Kit was used to detect the toxicity of astragalin. HE-staining, Immunohistochemical, Western blot and Enzyme Linked Immunosorbent Assay were applied to examine the clinicopathologic feature of AK and the change of p38 MAPK signal pathway treated with astraglin under the condition of UVB in vitro and in vivo. Results：In our clinical findings revealed that p38 MAPK, phospho-MSK1, and γ -H2AX were significantly highly expressed in human AK tissue than the normal healthy skin tissue. Moreover, in vitro studies showed that UVB induced the phospho-MSK1 and γ-H2AX in a time- and dose-dependent manner in HaCaT cells. Further, in vitro kinase assay demonstrated that astragalin could directly bind to p38 MAPK and suppress p38 MAPK activity. Furthermore, astragalin exhibited no toxicity and suppressed the UVB-induced expression of phospho- MSK1 and γ -H2AX by suppressing p38 MAPK activity in a time-dependent and dose-dependent manner in HaCaT cells. The in vivo studies with animal UV model demonstrated that astragalin inhibited UVB-induced expression of phospho-MSK1 and γ-H2AX in Babl/c mice.
These results suggested that p38 MAPK is a direct valid molecular target of astragalin for the attenuation of UVB-induced AK. Furthermore, astragalin could be a potential promising novel natural therapeutic agent for the prevention and management of UVB-induced AK with high target specificity and low toxicity.
光化性角化病（AK）是由过量紫外线B（UVB）诱导产生的最常见的癌前皮肤病变，对公众健康构成重大威胁。UVB暴露会导致氧化性DNA损伤，被认为是AK及后续皮肤癌发展的重要因素。此外，p38丝裂原活化蛋白激酶（p38 MAPK）的激活在AK的发展中也起着重要作用。
本研究旨在开发一种能够抑制UVB诱导的AK的天然化合物。
使用MTS细胞增殖检测试剂盒检测紫云英苷的毒性。采用苏木精-伊红（HE）染色、免疫组织化学、蛋白质印迹法和酶联免疫吸附测定法，在体外和体内UVB条件下，检测AK的临床病理特征以及经紫云英苷处理后p38 MAPK信号通路的变化。
我们的临床研究结果显示，与正常健康皮肤组织相比，p38 MAPK、磷酸化丝裂原和应激激活蛋白激酶1（phospho-MSK1）以及γ-H2AX在人AK组织中显著高表达。此外，体外研究表明，UVB在HaCaT细胞中以时间和剂量依赖性方式诱导phospho-MSK1和γ-H2AX。进一步的体外激酶测定表明，紫云英苷可直接结合p38 MAPK并抑制p38 MAPK活性。此外，紫云英苷无毒性，并通过在HaCaT细胞中以时间和剂量依赖性方式抑制p38 MAPK活性，抑制UVB诱导的phospho-MSK1和γ-H2AX的表达。在动物UV模型上进行的体内研究表明，紫云英苷可抑制Babl/c小鼠中UVB诱导的phospho-MSK1和γ-H2AX的表达。
这些结果表明，p38 MAPK是紫云英苷减轻UVB诱导的AK的直接有效分子靶点。此外，紫云英苷可能是一种具有潜力的新型天然治疗剂，用于预防和治疗UVB诱导的AK，具有高靶点特异性和低毒性。
