... In vitro activities of novel 4-HPR derivatives on a panel of rhabdoid and other tumor cell lines Melissa E Smith1, Bhaskar C Das 2,3,4, and Ganjam V Kalpana1,4,5 Department of Genetics, Albert ... combined chemotherapy and radiotherapy Radioactive derivatives can also be used to evaluate bioavailability of 4-HPR in vivo, using non-invasive imaging In addition, the peptidomimetic derivatives ... cancer cells by inducing apoptosis and, in some cases, cell cycle arrest at various stages [9-13] Inhibition of tumor cell growth by 4-HPR in vitro occurs at clinically achievable concentrations...