1. ¹Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
2. ²Department of Oncological Sciences, University of Utah, Salt Lake City, UT, USA
3. ³Department of Dermatology, University of Utah, Salt Lake City, UT, USA
4. ⁴Department of Medicine, University of Utah, Salt Lake City, UT, USA

Correspondence: Dr D Grossman, Department of Dermatology and Oncological Sciences, University of Utah/Huntsman Cancer Institute, 2000 Circle of Hope, Suite 5243, Salt Lake City, UT 84112, USA. E-mail: doug.grossman@hci.utah.edu

⁵These authors contributed equally to this work.

Received 30 December 2005; Revised 31 March 2006; Accepted 8 April 2006; Published online 15 May 2006.

Abstract

The inhibitor of apoptosis gene family member Survivin is highly expressed in most tumors, and appears to be a promising target for cancer therapy. Although a variety of Survivin antagonists have been shown to induce apoptosis in malignant cells, the potential utility of these agents is limited by inefficient delivery and cell impermeability. We generated recombinant fusion proteins containing the TAT protein transduction domain and either wild-type Survivin (TAT-Surv-WT) or a dominant-negative mutant (TAT-Surv-T34A). The TAT-Surv proteins were purified by sequential affinity and ion–exchange chromatography, and at 30 nM concentration demonstrated rapid entry into cells at 30 min. Whereas TAT-Surv-WT had minimal effect on YUSAC2 or WM793 melanoma cells, TAT-Surv-T34A induced cell detachment, DNA fragmentation, caspase-3 activation and mitochondrial release of apoptosis-inducing factor at low M concentrations. Intraperitoneal (i.p.) injection of mice bearing subcutaneous YUSAC2 xenografts with TAT-Surv-T34A (10 mg/kg) was associated with rapid tumor accumulation at 1 h, and increased tumor cell apoptosis and aberrant nuclei formation in situ. Repeated i.p. injection of TAT-Surv-T34A resulted in a 40–50% reduction in growth and mass of established tumors, compared to those similarly injected with saline buffer or TAT-Surv-WT. These studies demonstrate the feasibility of systemic tumor treatment using a cell-permeable Survivin antagonist.