Most human tumors find ways to resist anticancer drug monotherapy. Akt is considered a likely peptide providing such monotherapy drug resistance. Data indicates that Akt chemoresistance is induced in a p53-dependent manner and that inhibition of Akt may be an effective means of overcoming chemoresistance in cancer cells expressing wild-type p53. Breast, ovarian, lung cancer and leukemia cells lines were treated with combinations of Akt activation inhibitor Triciribine (TCN) or Triciribine phosphate (TCNP) and chemotherapeutic drugs to determine the efficiency of combination therapy. Additionally, cells were introduced into xenograft models to determine in vivo effects of combination treatment. Combining TCN or TCNP with other anticancer drugs overcame cytotoxic or treatment resistance. Thus, TCN and TCNP are shown to broaden the spectrum of human tumors that can be effectively treated.