title: Taxol, a microtubule-stabilizing antineoplastic agent, differentially regulates normal and tumor-bearing host macrophage nitric oxide production.
abstract: Taxol, a potent antitumor chemotherapeutic, promotes in vitro cytotoxic antitumor activities by normal host macrophage (M phi s). Because tumor growth induces functional changes among M phi populations, we determined whether fibrosarcoma growth (Meth-KDE) modified M phi responsiveness to the activating agent taxol. Tumors induce tumor-distal M phi populations to become immune suppressor cells, partially through overproduction of the cytotoxic and proinflammatory molecules nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha). Beneficial to the tumor-bearing host (TBH) when released by tumor-proximal M phi s, NO and TNF-alpha suppress lymphoproliferation and fail to impart antitumor activity when expressed in tumor-distal compartments. We report that taxol differentially regulated normal host and TBH M phi production of the immunosuppressive molecule NO by tumor-distal M phi populations. In response to IFN-gamma-priming and taxol triggering, TBH M phi s increase their production of NO as compared to resting M phi s; however, unlike normal host M phi s, taxol-induced TBH M phi NO production was significantly suboptimal. Modulation of TBH M phi NO production in tumor-distal compartments may alleviate M phi-mediated suppression of T-cell proliferative responses, yet promote sufficient NO production by tumor-associated M phi s to affect cytotoxicity. Collectively, these data leave implications for immunotherapeutic activities by the anticancer drug taxol.
authors.affiliation: Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0406, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Mullins
authors.forename: D G
authors.initials: DG
authors.lastname: Alleva
authors.forename: C J
authors.initials: CJ
authors.lastname: Burger
authors.forename: K D
authors.initials: KD
authors.lastname: Elgert
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D005354:Fibrosarcoma / Q000188:drug therapy / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008870:Microtubules / Q000187:drug effects; D009368:Neoplasm Transplantation; D009569:Nitric Oxide / Q000096:biosynthesis*; D017239:Paclitaxel / Q000494:pharmacology*; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D017239:Paclitaxel