In order to design short hairpin RNA (shRNA) conform to demands in our experiments, we cooperated with SYSU-Software from Sun Yat-sen University to develop a corresponding software. We provided algorithms and design requirements, and SYSU-Software wrote this delicate software for us. With its help, we successfully designed K-ras siRNA, whose sequence and predicted structure are shown below. We validated that this shRNA was able to down-regulate the expression level of K-ras in A549 effectively. We thank our collaborator for receiving us with attention and for such strong contribution to our work