Design, syntheses and biological evaluation of natural product aiphanol derivatives and analogues: Discovery of potent anticancer agents.

The natural product aiphanol (1) is one of the substances with anticancer biological activity isolated from traditional Chinese medicines (TCM) Smilax glabra Roxb. (Tufuling). Our recent research found that aiphanol could suppress angiogenesis and tumor growth by dual-blocking VEGF/VEGFRs and COX2 signal pathway. In this study, four series of 40 aiphanol derivatives and analogues were designed, synthesized and evaluated for their anticancer activity. Among them, the analogues 10j and 14c exhibited the most potent inhibition and broad-spectrum antiproliferative activity toward nine tumor cell lines. The IC50 values of the analogues 10j and 14c range from 0.81 to 10 µmol/L which up to 80-fold vs. parent compound aiphanol. The structure-activity relationship (SAR) studies indicated that the substrate at 7-position of benzo 1,4-dioxane is very crucial for anticancer activity. Molecular docking indicated that the compound 14c (ent-14c) tightly binds to VEGFR2 and COX2, respectively. Therefore, compounds 10j and 14c could be promising candidates for the development of anticancer agents in the future.

Aiphanol, a multi-targeting stilbenolignan, potently suppresses mouse lymphangiogenesis and lymphatic metastasis.

The high incidence of lymphatic metastasis is closely related to poor prognosis and mortality in cancers. Potent inhibitors to prevent pathological lymphangiogenesis and lymphatic spread are urgently needed. The VEGF-C-VEGFR3 pathway plays a vital role in driving lymphangiogenesis and lymph node metastasis. In addition, COX2 in tumor cells and tumor-associated macrophages (TAMs) facilitates lymphangiogenesis. We recently reported that aiphanol, a natural stilbenolignan, attenuates tumor angiogenesis by repressing VEGFR2 and COX2. In this study, we evaluated the antilymphangiogenic and antimetastatic potency of aiphanol using in vitro, ex vivo and in vivo systems. We first demonstrated that aiphanol directly bound to VEGFR3 and blocked its kinase activity with an half-maximal inhibitory concentration (IC50) value of 0.29 µM in an in vitro ADP-GloTM kinase assay. Furthermore, we showed that aiphanol (7.5-30 µM) dose-dependently counteracted VEGF-C-induced proliferation, migration and tubular formation of lymphatic endothelial cells (LECs), which was further verified in vivo. VEGFR3 knockdown markedly mitigated the inhibitory potency of aiphanol on lymphangiogenesis. In 4T1-luc breast tumor-bearing mice, oral administration of aiphanol (5 and 30 mg· kg-1 ·d-1) dose-dependently decreased lymphatic metastasis and prolonged survival time, which was associated with impaired lymphangiogenesis, angiogenesis and, interestingly, macrophage infiltration. In addition, we found that aiphanol decreased the COX2-dependent secretion of PGE2 and VEGF-C from tumor cells and macrophages. These results demonstrate that aiphanol is an appealing agent for preventing lymphangiogenesis and lymphatic dissemination by synergistically targeting VEGFR3 and inhibiting the COX2-PGE2-VEGF-C signaling axis.

A multi-targeting natural product, aiphanol, inhibits tumor growth and metastasis.

Cancer is one of the main causes of death in humans worldwide, the development of more effective anticancer drugs that can inhibit the malignant progression of cancer cells is of great significance. Aiphanol is a natural product identified from the seeds of Arecaceae and the rhizome of Smilax glabra Roxb. Our preliminary studies revealed that it had potential antiangiogenic and antilymphangiogenic activity by directly targeting VEGFR2/3 and COX2 in endothelial cells. However, the influence of aiphanol on cancer cells per se remains largely undefined. In this study, the effects and related mechanisms of aiphanol on cancer growth and metastasis were evaluated in vitro and in vivo. Acute toxicity assay and pharmacokinetic analysis were utilized to investigate the safety profile and metabolism characteristics of aiphanol. We revealed that aiphanol inhibited the proliferation of various types of cancer cells and the growth of xenograft tumors in mice and zebrafish models. The possible mechanism was associated with the inactivation of multiple kinases, including FAK, AKT and ERK, and the upregulation of BAX and cleaved caspase-3 to promote cancer cell apoptosis. Aiphanol significantly inhibited cancer cell migration and invasion, which was related to the inhibition of epithelial-mesenchymal transition (EMT) and F-actin aggregation. Aiphanol effectively attenuated the metastasis of several types of cancer cells in vivo. In addition, aiphanol exerted no significant toxicity and had fast metabolism. Collectively, we demonstrated the anticancer effects of aiphanol and suggested that aiphanol has potential as a safe and effective therapeutic agent to treat cancer.