Paeonol repurposing for cancer therapy: From mechanism to clinical translation.

Paeonol (PAE) is a natural phenolic monomer isolated from the root bark of Paeonia suffruticosa that has been widely used in the clinical treatment of some inflammatory-related diseases and cardiovascular diseases. Much preclinical evidence has demonstrated that PAE not only exhibits a broad spectrum of anticancer effects by inhibiting cell proliferation, invasion and migration and inducing cell apoptosis and cycle arrest through multiple molecular pathways, but also shows excellent performance in improving cancer drug sensitivity, reversing chemoresistance and reducing the toxic side effects of anticancer drugs. However, studies indicate that PAE has the characteristics of poor stability, low bioavailability and short half-life, which makes the effective dose of PAE in many cancers usually high and greatly limits its clinical translation. Fortunately, nanomaterials and derivatives are being developed to ameliorate PAE's shortcomings. This review aims to systematically cover the anticancer advances of PAE in pharmacology, pharmacokinetics, nano delivery systems and derivatives, to provide researchers with the latest and comprehensive information, and to point out the limitations of current studies and areas that need to be strengthened in future studies. We believe this work will be beneficial for further exploration and repurposing of this natural compound as a new clinical anticancer drug.

Therapeutic Effects of Punicalagin Against Ovarian Carcinoma Cells in Association With ß-Catenin Signaling Inhibition.

AIM: The aim of this study was to investigate the effects of punicalagin, a polyphenol isolated from Punica granatum, on human A2780 ovarian cancer cells in vitro. METHODS: The viability of human A2780 ovarian cells was evaluated using Cell Counting Kit-8 assay. Cell cycle was detected with flow cytometry analysis. The protein expression levels of Bcl-2, Bax, ß-catenin, cyclin D1, survivin, tissue inhibitor of metalloproteinase (TIMP)-2, and TIMP-3 were measured using Western blot analysis. Matrix metalloproteinase (MMP)-2 and MMP-9 activity was determined with gelatin zymography. Wound healing assay was used to determine cell migration. RESULTS: Punicalagin inhibited the cell viability of A2780 cells in a dose- and time-dependent manner, and the cell cycle of A2780 cells was arrested in G1/S phase transition. The treatment also induced apoptosis as shown by the up-regulation of Bax and down-regulation of Bcl-2. On the other hand, punicalagin treatment increased the expressions of TIMP-2 and TIMP-3, decreased the activities of MMP-2 and MMP-9, and inhibited cell migration. In addition, the ß-catenin pathway was suppressed as shown by the down-regulations of ß-catenin and its downstream factors including cyclin D1 and survivin. CONCLUSIONS: Punicalagin may have cancer-chemopreventive as well as cancer-chemotherapeutic effects against human ovarian cancer in humans through the inhibition of ß-catenin signaling pathway.

Realgar-induced apoptosis of cervical cancer cell line Siha via cytochrome c release and caspase-3 and caspase-9 activation.

OBJECTIVE: To explore the molecular mechanism of realgar-induced apoptosis of cervical cancer cells. METHODS: The cervical cancer cell line Siha was used to determine the cell viability and apoptosis after treatment with realgar using MTT assay and flow cytometry. The activities of caspase-3, -8, and -9 were detected by fluorescence resonance energy transfer technology and colorimetric assay, while the levels of Bcl-2, cytochrome c, and Bax were detected by Western blot method. RESULTS: Induction of apoptosis by realgar was detected in Siha cell line in a dose-dependent manner. The apoptosis was accompanied by a significant increase in cytochrome c release and activation of caspase-3 and caspase-9 but not caspase-8. Further, the realgar-induced apoptosis was inhibited by a broad-spectrum caspase inhibitor, a caspase-3 inhibitor, and a caspase-9 inhibitor but not by a caspase-8 inhibitor. Bcl-2 and Bax protein expressions were not changed by realgar. CONCLUSION: The induction of apoptosis by realgar is mediated through a cytochrome c-dependent pathway, which sequentially activates caspase-9 and caspase-3.