Expression of intracellular regulators of apoptosis in TRAIL-sensitive and TRAIL-resistant myeloma cells.

Immunoblot analysis was used to examine cell lysates from myeloma cells that are moderately resistant (ARH-77), highly resistant (HS-Sultan, IM-9), or sensitive (MM.1S, MM.1R, RPMI 8226, RPMI-Dox 40, ARP-1) to TRAIL for expression of apoptosis-inducing (procaspase-8 and FADD) or apoptosis-blocking (FLIP, cIAP1, cIAP2, XIAP, and survivin) proteins. Equal protein loading was ensured by demonstration of uniform tubulin expression.