Immunomodulatory activity of two new aza alkyl phospholipid antineoplastic drugs

The present work reports the modulation of immunocompetent cell functions by two aza alkyl phospholipids (AAP), BN 52205 and BN 52211. Each compound was compared with 1-O-octadecyl-2-O-rac-glycero-3-phosphocholine (ET-18-OCH3) and/or three drugs used for cancer treatment, i.e. cisplatyl (CIS), 5-fluorouracil (5-FU) and cytosine arabinoside (ARA-C). Interleukin (IL)-1 release from P388D1 cells was increased 2-fold in the presence of 5 micrograms/ml BN 52205 or BN 52211. However, these stimulations were lower than those obtained with ARA-C, 5-FU and CIS. Compared with ET-18-OCH3, CIS and 5-FU, BN 52205 and BN 52211 were more efficient in increasing tumor necrosis factor production induced by lipopolysaccharide (LPS) from human monocytes. In vitro, all compounds exhibited similar activity in enhancing IL-6 production from human monocytes stimulated with LPS, with the exception of 5-FU and CIS that were inactive. At 20 mg/kg (i.v.), a peak of IL-6 production was reached 2 h after injection of ET-18-OCH3 [> 1280 U/ml (n = 4, p < 0.001) versus 3.5 +/- 0.2 U/ml (n = 7)], whereas BN 52211 induced a maximum of IL-6 production after 4 h (77 +/- 27 U/ml, n = 5, p < 0.001). BN 52205 induced peaks of IL-6 production after 3 and 6 h (90 +/- 62 and 68 +/- 35 U/ml, respectively, p < 0.001, n = 4). The proliferation of rat splenocytes was abolished in the presence of BN 52205 and BN 52211 at 10 micrograms/ml, corresponding to only a partial reduction of IL-2 production at the same concentration. The production of interferon-gamma was stimulated 6- to 10-fold in the presence of 1-5 micrograms/ml BN 52205, BN 52211 and ARA-C. BN 52211 and BN 52205 were also potent enhancers of IL-3 production, whereas 5-FU and ARA-C were inhibitory. These results indicate that in addition to a direct antitumoral effect, AAP may also exhibit immunomodulatory activity both in vitro and in vivo.