Recombinant human holo-lactoferrin in complex with oleic acid suppresses the growth of solid myeloma more efficiently than its apo-form.

Our previous study showed antitumor activity of the complex formed by iron-free recombinant human lactoferrin (apo-recHLF) and oleic acid (OA) (1:8 molar ratio) in a model of murine hepatoma 22a inoculated to C3HA mice. Taken alone, apo-recHLF was less efficient; i.e., the tumor growth index was 0.14 for recHLF-8OA and 0.63 for recHLF as compared with 1.0 in the control animals. In the present study, we evaluated antitumor activity of iron-saturated recHLF per se and of the complexes formed by OA with apo-recHLF and holo-recHLF. Balb/c mice with solid myeloma Sp2/0 were subjected to the 10-day treatment with daily intraperitoneal (i/p) injections of 10 mg iron-saturated recHLF with OA (1:8) per animal (0.4 g/kg). In 15 days, the tumor growth was substantially inhibited. Mean tumor mass was 93% lower as compared with the control value (p < 0.01). I/p injections of apo-recHLF/OA complex did not inhibit the tumor growth. Holo-recHLF used without OA had less pronounced antitumor effect as compared with their complex.