Jolkinolide B induces apoptosis and G1 arrest in A549 cells via JAK2/STAT3 inhibition

Lung cancer is the most common pulmonary malignancy. WHO data show that its incidence and mortality are rising globally, severely threatening public health.

This study aims to investigate the regulatory effect of Jolkinolide B (JB) on lung cancer A549 cells and to preliminarily explore the potential molecular mechanisms underlying its anti-lung cancer effects.

In this study, A549 lung adenocarcinoma cells were used to investigate the anti-lung cancer effects of JB. CCK-8 and colony formation assays were performed to evaluate cell proliferation. Molecular docking and molecular dynamics simulation were applied to verify the binding between JB and JAK2, while Western blot was used to detect the expression of JAK2/STAT3 pathway-related proteins. Flow cytometry, immunofluorescence and Western blot were employed to explore the regulatory roles of JB in cell apoptosis and cycle. In addition, a nude mouse xenograft model was established and HE staining and immunohistochemistry were used to verify the in-vivo efficacy of JB. All data were statistically analyzed using GraphPad Prism and SPSS.

The results demonstrated that JB inhibited A549 cell proliferation in a dose‑dependent manner with an IC50 of 39.34 μM at 24 h. JB bound stably to JAK2 (PDB: 7RN6) with a binding free energy of -8.33 kcal/mol and suppressed the JAK2/STAT3 pathway. JB significantly promoted apoptosis and induced G1‑phase arrest via regulating P21, Cyclin D1, BAX, Caspase 3, PARP1 and Bcl‑2. In-vivo, JB reduced tumor growth in a dose‑dependent manner, induced tumor cell necrosis and downregulated p‑JAK2 and p‑STAT3 expression.

Jolkinolide B can significantly inhibit the proliferation of human lung adenocarcinoma A549 cells. Its mechanism of action is closely related to inducing cell cycle arrest and promoting cell apoptosis. The above effects may be partially achieved by inhibiting the JAK2/STAT3 pathway. In animal experiments, JB also significantly inhibits the growth of lung cancer transplanted tumors.