Abstract 1000: Treatment efficiency of regorafenib combined with magnolol was associated with suppression of VEGF and Mcl-1 on hepatocellular carcinoma
Authors: Yueh Po-Fu , Tan Zhao-Lin , Chiang Yuan , Chiang I-Tsang , Lan Keng-Li , Hus Fei-Ting 
Published: July 2021

Hepatocellular carcinoma (HCC) was known as a malignant tumor that has been reported with vascular endothelial growth factor (VEGF) and myeloid cell leukemia 1 (Mcl-1) overexpression. Both VEGF and Mcl-1 are the important downstream factors of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) which was also reported to highly associated with HCC progression. Regorafenib a multi-kinase inhibitor of HCC can inhibit part of the expression of VEGF and Mcl-1 in HCC. However, the single treatment efficiency of regorafenib on HCC still needs to be improved. Due to the important role of VEGF and Mcl-1 in HCC progression, we hypothesize that enhance the inhibition of VEGF and Mcl-1 could ameliorate regorafenib therapeutic effect. Magnolol is a natural compound extract from the bark of Magnolia officinalis. It has been demonstrated as a multifunctional bioactive compound by several studies, including anti-inflammation, antioxidation, anti-cancer⋯etc. In this study, we aim to combine magnolol with regorafenib to enhance the inhibition efficacy of VEGF and Mcl-1 and thus improve therapeutic efficiency on HCC. We used SK-Hep1 and Hep3B cells to perform this project. In in vitro study, recombination protein VEGF, VEGF interference RNA (siVEGF), Mcl-1 interference RNA (siMcl-1) and magnolol were used to investigate the mechanism of these reagents combine with regorafenib. Here we used MTT assay and NF-κB reporter gene assay to investigate the viability of cells and the regulation of NF-κB under VEGF induction condition and/or combined with regorafenib. To validate the alteration of apoptosis and migration after regorafenib combined with magnolol, we performed flow cytometry, immunofluorescence, comet assay, and transwell assay. For in vivo study, Hep3B cells were subcutaneously inject into nude mice and treated magnolol, regorafenib, and combination treatment. The protein regulation of regorafenib combined with magnolol on tumor tissues was assayed by Western blotting. The suppression of VEGF and Mcl-1 was markedly enhanced in regorafenib combined with magnolol as compare to single treatment. In addition, the apoptosis effect was effectively increased and the migration ability were effectively suppressed by regorafenib combined with magnolol as compare to single treatment. Greatest Hep3B tumor growth inhibition was found in the combination treatment group as compared to single treatments. IHC staining also revealed that NF-κB mediated tumor progression markers, such as VEGF and Mcl-1 were significantly reduced after combination treatment as compared to single therapy.Taken together, regorafenib combined with magnolol showed greater anti-HCC efficacy which may majorly correlate to the enhancing regorafenib-induced suppression of VEGF and Mcl-1.

Citation Format: Po-Fu Yueh, Zhao-Lin Tan, Yuan Chiang, I-Tsang Chiang, Keng-Li Lan, Fei-Ting Hus. Treatment efficiency of regorafenib combined with magnolol was associated with suppression of VEGF and Mcl-1 on hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1000.