Design, Synthesis, and Biological Evaluation of Novel Biotinylated Podophyllotoxin Derivatives as Potential Antitumor Agents oleh Cheng-Ting Zi, Cheng-Ting Zi, Cheng-Ting Zi, Ying-Sheng Gao, Liu Yang, Shu-Yun Feng, Yue Huang, Li Sun, Yi Jin, Feng-Qing Xu, Fa-Wu Dong, Yan Li, Zhong-Tao Ding, Jun Zhou, Zi-Hua Jiang, Sheng-Tao Yuan, Jiang-Miao Hu