Caffeic acid hinders the proliferation and migration through inhibition of IL-6 mediated JAK-STAT-3 signaling axis in human prostate cancer.

Background: Caffeic acid (CA) is considered a promising phytochemical that has inhibited numerous cancer cell proliferation. Therefore, it is gaining increasing attention due to its safe and pharmacological applications. In this study, we investigated the role of CA in inhibiting the Interleukin-6 (IL-6)/Janus kinase (JAK)/Signal transducer and activator of transcription-3 (STAT-3) mediated suppression of the proliferation signaling in human prostate cancer cells.

Materials and methods: The role of CA in proliferation and colony formation abilities was studied using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and colony formation assays. Tumour cell death and cell cycle arrest were identified using flow cytometry techniques. CA treatment-associated protein expression of mitogen-activated protein kinase (MAPK) families, IL-6/JAK/STAT-3, proliferation, and apoptosis protein expressions in PC-3 and LNCaP cell lines were measured using Western blot investigation.

Results: We have obtained that treatment with CA inhibits prostate cancer cells (PC-3 and LNCaP) proliferation and induces reactive oxygen species (ROS), cell cycle arrest, and apoptosis cell death in a concentration-dependent manner. Moreover, CA treatment alleviates the expression phosphorylated form of MAPK families, i.e., extracellular signal-regulated kinase 1 (ERK1), c-Jun N-terminal kinase (JNK), and p38 in PC-3 cells. IL-6 mediated JAK/STAT3 expressions regulate the proliferation and antiapoptosis that leads to prostate cancer metastasis and migration. Therefore, to mitigate the expression of IL-6/JAK/STAT-3 is considered an important target for the treatment of prostate cancer. In this study, we have observed that CA inhibits the expression of IL-6, JAK1, and phosphorylated STAT-3 in both PC-3 and LNCaP cells. Due to the inhibitory effect of IL-6/JAK/STAT-3, it resulted in decreased expression of cyclin-D1, cyclin-D2, and CDK1 in both PC-3 cells. In addition, CA induces apoptosis by enhancing the expression of Bax and caspase-3; and decreased expression of Bcl-2 in prostate cancer cells.

Conclusions: Thus, CA might act as a therapeutical application against prostate cancer by targeting the IL-6/JAK/STAT3 signaling axis.