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Paclitaxel causes mouse splenic lymphocytes to a state hyporesponsive to lipopolysaccharide stimulation
1Cell Cycle and Signal Transduction Research Unit, Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon, South Korea. mikelee@kribb4680.kribb.re.kr
Abstract:
Multiple immune system actions have been ascribed to paclitaxel (taxol), a novel anticancer drug, including the capacity to induce macrophage antitumor cytotoxic molecule production. In the present studies, we demonstrated that paclitaxel produced a selective inhibition of lipopolysaccharide (LPS)-induced B cell proliferation. Similarly, in vitro polyclonal antibody-forming cell responses also were found to be inhibited by paclitaxel. Conversely, paclitaxel exhibited no inhibitory effects on concanavalin A (Con A)-induced T cell proliferation. To study the pathway leading to paclitaxel-induced immunosuppression, we analyzed Raf-1/ERK and JNK/p38 MAPK pathways, both of which have been reported to be involved in LPS signaling. Our results indicate that taxol treatment inhibits Raf-1 kinase activation while having no effect on ERK activation suggesting that ERK activation is distinct from upstream Raf-1 kinase in taxol-induced immunomodulation. Furthermore, paclitaxel pretreatment caused down-regulation of stress-activated MAPKs, JNK and p38 MAPK in lipopolysaccharide (LPS)-stimulated mouse splenic lymphocytes, demonstrating that spleen cells are induced to a state hyporesponsive to LPS stimulation by pre-exposing them to paclitaxel. Taken together, these results suggest that down-regulation of JNK/p38 MAP kinase may contribute to paclitaxel-induced immunosuppression in mouse splenic lymphocytes.
Insights
Paclitaxel (Taxol) selectively inhibits B cell proliferation and antibody production by down-regulating JNK/p38 MAPK pathways. This anticancer drug impacts immune responses, affecting specific lymphocyte functions.
Area of Science:
- Immunology
- Pharmacology
- Cell Biology
Background:
- Paclitaxel (Taxol) is a novel anticancer drug with known immune system effects.
- Its capacity to induce macrophage antitumor cytotoxic molecule production is established.
- However, its precise impact on lymphocyte function requires further elucidation.
Purpose of the Study:
- To investigate the effects of paclitaxel on B cell and T cell proliferation.
- To explore the molecular pathways, specifically Raf-1/ERK and JNK/p38 MAPK, involved in paclitaxel-induced immunomodulation.
- To determine if paclitaxel induces immunosuppression in splenic lymphocytes.
Main Methods:
- Assessing paclitaxel's effect on lipopolysaccharide (LPS)-induced B cell proliferation in vitro.
- Evaluating paclitaxel's impact on polyclonal antibody-forming cell responses.
- Analyzing the activation of Raf-1/ERK and JNK/p38 MAPK pathways in response to paclitaxel and LPS stimulation in mouse splenic lymphocytes.
Main Results:
- Paclitaxel selectively inhibited lipopolysaccharide (LPS)-induced B cell proliferation and in vitro polyclonal antibody-forming cell responses.
- Paclitaxel did not inhibit concanavalin A (Con A)-induced T cell proliferation.
- Paclitaxel treatment inhibited Raf-1 kinase activation but not ERK activation.
- Paclitaxel pretreatment led to the down-regulation of stress-activated MAPKs, JNK and p38 MAPK, in LPS-stimulated mouse splenic lymphocytes.
Conclusions:
- Paclitaxel selectively suppresses B cell immune responses.
- The inhibition of JNK/p38 MAPK pathways is a key mechanism contributing to paclitaxel-induced immunosuppression in splenic lymphocytes.
- These findings provide insights into the immunomodulatory effects of paclitaxel.