Inhibitory effect of berberine on interleukin-2 secretion from PHA-treated lymphocytic Jurkat cells.

Berberine is an isoquinoline alkaloid isolated from herb plants, such as Cortex phellodendri (Huangbai) and Rhizoma coptidis (Huanglian). Huanglian and Huangbai have been used as "heat-removing" agents. In addition, berberine has been reported to exert anti-inflammatory effect both in vivo and in vitro, where mitogen-activated protein kinase (MAPK) and cyclooxygenase-2 (COX-2) expressions are critically implicated. We herein tested the hypothesis that berberine exerts an anti-inflammatory effect through MAPK and COX-2 signaling pathway in T-cell acute lymphoblastic leukemia (T-ALL). In Jurkat cells, we found that PHA exposure caused elevation on interleukin-2 (IL-2) production in a time-dependent manner. PHA-stimulated reactions were steeply suppressed by berberine, such as IL-2 mRNA expression and protein secretion. However, berberine did not exert any cytotoxic effect at doses of 40 µg/ml. In addition, the possible molecular mechanism of anti-inflammation effect of berberine could be the inhibition of PHA-evoked phosphorylation of p38, since c-Jun N-terminal kinases (JNK) and extracellular signal-regulated kinase (ERK) expressions did not alter. Consistent with above results, berberine inhibition on PHA-induced IL-2 secretion could be reversed by treatment of SB203580, a specific inhibitor of p38-MAPK. Interestingly, upregulation of PHA-induced COX-2 expression was also observed following berberine treatment of Jurkat cells. Furthermore, flow cytometry analysis showed berberine-induced cell cycle arrest at G1 phase after PHA stimulation and decreased percentage of G2/M phase. In conclusion, our study demonstrated that the anti-inflammatory effect of berberine largely potentially results from its ability to attenuate p38 MAPK expression, and does not exclude a positive action of berberine on cell cycle arrest. These results provide an innovative medicine strategy to against or treat T-ALL patients.

Anti-inflammatory Effects of Gossypol on Human Lymphocytic Jurkat Cells via Regulation of MAPK Signaling and Cell Cycle.

Gossypol, a natural polyphenolic compound extracted from cottonseed oil, has been reported to possess pharmacological properties via modulation cell cycle and immune signaling pathway. However, whether gossypol has anti-inflammatory effects against phytohemagglutinin (PHA)-induced cytokine secretion in T lymphocytes through similar mechanism remains unclear. Using the T lymphocytes Jurkat cell line, we found that PHA exposure caused dramatic increase in interleukin-2 (IL-2) mRNA expression as well as IL-2 secretion. All of these PHA-stimulated reactions were attenuated in a dose-dependent manner by being pretreated with gossypol. However, gossypol did not show any in vitro cytotoxic effect at doses of 5-20 µM. As a possible mechanism underlying gossypol action, such as pronounced suppression IL-2 release, robust decreased PHA-induced phosphorylation of p38 and c-Jun N-terminal kinase expressions was found with gossypol pretreatment, but not significant phosphorylation of extracellular signal-regulated kinase expression. Furthermore, gossypol could suppress the Jurkat cells' growth, which was associated with increased percentage of G1/S phase and decreased fraction of G2 phase in flow cytometry test. We conclude that gossypol exerts anti-inflammatory effects probably through partial attenuation of mitogen-activated protein kinase (phosphorylated JNK and p38) signaling and cell cycle arrest in Jurkat cells.