We have used multiple methods to introduce plasmids containting target cDNA or siRNA or shRNA into multiple myeloma cell lines. These methods include Amaxa Nucleofector, lipofectamine, and electroporation, and retrovirus vector expression system and Lentivirus vector expression system. The highest transfection (infection) efficiency among these methods is lentivirus vector expressing system, the gift from lab of Prof. Didier Trono (Université de Genève, Switzerland). Besides the high efficiency, cDNA in lentivirus expressing vector integrates with chromosome of the cells and thus prevents leaking of ectopic expressing genes in the vector from the expressed cells after culture of myeloma cells in vitro for long time.
I am also facing a similar problem in transfecting myeloma cell lines. I have tried all lipid based reagents and non of them have worked. I am now trying Amaxa nucleofection and trying to optimize the best program. I have tried those settings recommended by Amaxa, but all of my cells were killed. So I am now trying different settings. May I know which myeloma cell lines are you transfecting? I am using RPMi 8226 and U266.
I will update you as I have some positive results.