MEROCYANINE 540-SENSITIZED PHOTOINACTIVATION OF HIGH-GRADE NON-HODGKINS-LYMPHOMA CELLS - POTENTIAL APPLICATION IN AUTOLOGOUS BMT

This paper reports on the preclinical evaluation of merocyanine 540 (M C540) as an agent for the inactivation of tumour cells in BM grafts fr om non-Hodgkin's lymphoma (NHL) patients. The three cell lines used fo r this study, OCI-LY13.1, OCI-LY13.2 and OCI-LY9, originate from two p atients with high-grade NHL. The OCI-LY13.1 and OCI-LY13.2 lines are d erived from the same patient. The OCT-LY13.1 line was established at t he time of diagnosis while the OCI-LY13.2 line was established after t he tumour had become refractory to therapy. When used under conditions that are known to preserve about 50% of normal human pluripotent hema topoietic progenitor cells (CFU-GEMM), MC540-sensitized photoirradiati on reduced in vitro clonogenic OCI-LY9 cells by 4 orders of magnitude and OCI-LY13.1 and OCI-LY13.2 cells by greater-than-or-equal-to 5. Sur vival curves for OCI-LY13.1 and OCI-LY13.2 cells were similar and foll owed first order kinetics, while those for OCI-LY9 cells were distinct ly biphasic. Suspension cultures established with photoinactivated lym phoma cells confirmed that MC540-sensitized photoirradiation was cytot oxic and capable of eliminating greater-than-or-equal-to 4 log of tumo ur cells. These results encourage the further exploration of MC540-sen sitized photoirradiation as a means to purge autologous marrow grafts from NHL patients.