Differential Phosphorylations of NFkB and Cell Growth of MDA-MB 231 Human Breast Cancer Cell Line by Limonins Conference Paper uri icon


  • The present research focused on investigating cell growth inhibition and total and differential NFkB serine residue phosphorylations on estrogen insensitive MDA-MB 231 breast cancer cells by various citrus limonoids and camptothecin. A cell growth assay was carried out after a 24 hr incubation with various concentrations of limonin glucoside, limonin, obacunone and obacunone glucoside (1, 5 and 10 M) and camptothecin (10 M), as a standard chemotherapy drug, along with DMSO solvent control. NFkB phosphorylations were assayed using a commercially available NFkB Elisa profiler kit (Active motif, Carlsbad CA) on these cells. The specific serine residue phosphorylation was studied using respective anti-phospho serine antibodies (anti-phospho ser-468 and ser-536, respectively) supplied in the kit. The WST-1 cell growth assay showed that limonoids, at all tested concentrations, did not show a significant decrease in MDA-MB 231 cell growth when compared to camptothecin (37-40% growth inhibition). The NFkB p65 profiler Elisa assay with 10 uM concentration of three types of limonoids (limonin glucoside, obacunone and obacunone glucoside) exhibited a significant increase (50%) and limonin showed only a 10% increase in ser-468 residue phosphorylations than DMSO treated cells. However, camptothecin treated hormone insensitive cells exhibited a 50% increase in the phosphorylations of both ser-536 and ser-468 residues than DMSO treated cells and inhibiting the cell growth. The total constitutive NFkB phosphorylation activity of limonoids treated, show a decrease than DMSO treated control cells. On the other hand, camptothecin treated cells showed a significant increase in total constitutive NFkB phosphorylation activity. These results may suggest that hormone insensitive MDA-MB 231 cell growth were not inhibited by limonin glucoside, limonin, obacunone and obacunone glucoside, but perhaps was due to differential phosphorylations of serine residues of NFkB.

published proceedings


author list (cited authors)

  • Somasundaram, S., Pearce, K., Gunasekera, R., Jayaprakasha, G. K., & Patil, B.

citation count

  • 2

complete list of authors

  • Somasundaram, S||Pearce, K||Gunasekera, R||Jayaprakasha, GK||Patil, B

publication date

  • August 2009