A robust ex vivo model for evaluation of induction of apoptosis by rhTRAIL in combination with proteasome inhibitor MG132 in human premalignant cervical explants

Development of medical therapies for high-grade cervical intraepithelial neoplasia (CIN II/III) is hampered by the lack of CIN II/III cell lines. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis upon binding to its receptors DR4 or DR5. Proteasome inhibition by MG132 sensitized cervical cancer cell lines to recombinant human (rh)TRAIL. In our study, we aimed to develop an ex vivo model for CIN II/III and to investigate (lie apoptosis-inducing effect of rhTRAIL, and/or MG132 in cervical explants front CIN II/III patients. A short-term ex viva culture system was optimized for cervical biopsies, in which explants from normal cervix and CIN II/III lesions were exposed to either rhTRAIL, (1 mu g/ml), MG132 (5 mu M) or the combination and compared to untreated explants for apoptosis induction. Normal cervix (n = 90) and CIN II/III (n = 24) explants could be reproducibly put in culture and kept viable for of) to 7 days using a transwell membrane system. CIN II/III explants (n = 5) were highly sensitive to rhTRAIL plus MG132 (mean % apoptosis: 91 +/- 5) compared to normal cervix (n = 10) treated with rhTRAIL, plus MG132 (mean % apoptosis: 24 +/- 10, p <0.0001), while monotherapy with either rhTRAIL, MG132 or medium resulted in a mean % apoptosis