Alantolactone (Inula camphor)(Alant camphor), a sesquiterpene lactone, has potential activity against triple-negative breast Y MDA-MB-231 cells by suppressing the signal transducer and activator of transcription 3 (STAT3) signaling pathway.

Alantolactone selectively suppresses STAT3 activation and exhibits potent anticancer activity in MDA-MB-231 cells. Alantolactone effectively suppressed both constitutive and inducible STAT3 activation at tyrosine 705. It decreased STAT3 translocation to the nucleus, its DNA-binding, and STAT3 target gene expression. Alantolactone significantly inhibits STAT3 activation with a marginal effect on MAPKs and on NF-κB transcription; however, this effect is not mediated by inhibiting STAT3 upstream kinases. SHP-1, SHP-2, and PTEN, which are protein tyrosine phosphatases (PTPs) were not affected by alantolactone. Alantolactone treatment resulted in the inhibition of migration, invasion, adhesion, and colony formation[1]. Alantolactone could induce activin signaling and activin target gene expression. Alantolactone activated the activin signaling pathway in a cancer cell line. It could promote SMAD2/3 nuclear translocation in a very short time[3].

In vivo administration of alantolactone inhibited the growth of human breast xenograft tumors[1]. Alantolactone exerts no toxic effect on liver and kidneys in vivo, The drug was well tolerated by mice and no mortality or any sign of pharmacotoxicity was found at a dose of 100 mg/kg during all the experimental periods. Alantolactone can cross blood-brain barrier[2].

Cell viability was evaluated using MTT assay. The cells were seeded into 96-well plates and maintained at 37 °C for 24 h. The cells were treated with alantolactone for 24 h. The MTT solution (0.5 mg/mL) was added to each well, and the cells were incubated for another 3 h. The MTT formazan crystals were dissolved in DMSO. The results were obtained by measuring the absorbance at a wavelength of 540 nm using a microplate reader.(Only for Reference)