Sensitization effect of kaempferol from persimmon leaves on HepG2 hepatoma cells with ABT-199 resistance and its molecular mechanisms

Mcl-1 is an important target protein for kaempferol from persimmon leaves in sensitizing ABT-199 to induce apoptosis in hepatoma cancer cells

Overexpression of Mcl-1 causes hepatocellular carcinoma resistance to Bcl-2 inhibitors, but there are currently no direct Mcl-1 inhibitors available for clinical application. Our previous research demonstrated that kaempferol from persimmon leaves (KPL) can sensitize ABT-199 to inhibit liver cancer cell proliferation. This study further explored the effect of KPL sensitizing ABT-199 on liver cancer cell apoptosis and its potential mechanisms. The inhibitory effects of KPL and ABT-199, both individually and in combination, on the proliferation of HepG2, Huh7, and HCCLM3 cells were evaluated. Cell apoptosis and mitochondrial morphology were assessed with flow cytometry and confocal microscopy, respectively. Apoptosis and changes in Mcl-1 protein expression were evaluated after siMcl-1 knockdown. Molecular docking simulations were used to analyze the interactions of KPL and ABT-199, both individually and in combination, with Mcl-1 protein. The effect of KPL on Mcl-1 stability was investigated with proteasome inhibitor MG132. The results demonstrated that KPL showed a strong sensitizing effect on ABT-199 (CI value < 1), enhanced liver cancer cell proliferation inhibition and increased apoptosis rate. Combined treatment led to mitochondrial fragmentation and swelling, and significantly reduced Mcl-1 expression. siMcl-1 interference resulted in little difference in apoptosis rates and Mcl-1 expression between the combination treatment and untreated groups. Molecular docking revealed that KPL increased the affinity of ABT-199 for Mcl-1, whereas MG132 prevented KPL from downregulating Mcl-1 expression. These findings suggest that KPL enhances ABT-199-induced apoptosis in HCC cells by targeting Mcl-1 protein through increasing the affinity between ABT-199 and Mcl-1, while also promoting Mcl-1 degradation by affecting post-translational modifications.

Pharmacodynamics and safety in relation to dose and response of plant flavonoids in treatment of cancers

Despite the recent advancements in developing bioactive nutraceuticals as anticancer modalities, their pharmacodynamics, safety profiles, and tolerability remain elusive, limiting their success in clinical trials. The failure of anticancer drugs in clinical trials can be attributed to the changes in drug clearance, absorption, and cellular responses, which alter the dose-response efficacy, causing adverse health effects. Flavonoids demonstrate a biphasic dose-response phenomenon exerting a stimulatory or inhibitory effect and often follow a U-shaped curve in different preclinical cancer models. A double-edged sword, bioflavonoids' antioxidant or prooxidant properties contribute to their hormetic behavior and facilitate redox homeostasis by regulating the levels of reactive oxygen species (ROS) in cells. Emerging reports suggest a need to discuss the pharmacodynamic broad-spectrum of plant flavonoids to improve their therapeutic efficacy, primarily to determine the ideal dose for treating cancer. This review discusses the dose-response effects of a few common plant flavonoids against some types of cancers and assesses their safety and tolerability when administered to patients. Moreover, we have emphasized the role of dietary-rich plant flavonoids as nutraceuticals in cancer treatment and prevention.

3DSTarPred: A Web Server for Target Prediction of Bioactive Small Molecules Based on 3D Shape Similarity

Target identification plays a critical role in preclinical drug development. The in silico approach has been developed and widely applied to assist medicinal chemists and pharmacologists in drug target identification. There are many target prediction web servers available today that have revealed both advantages and shortcomings in practical applications. Here, we present 3DSTarPred, a web server for three-dimensional (3D) shape similarity-based target prediction of small molecules. A benchmark study showed that 3DSTarPred achieved a target prediction success rate of 76.27%, which was higher than that of existing target prediction web servers. In addition, the performance of 3DSTarPred in the target prediction of diverse substructures/superstructures was also better than that of the existing target prediction web servers. In case studies, 3DSTarPred was used to identify the potential targets of two small molecules, one being kaempferol, a natural lead compound for the treatment of Alzheimer's disease (AD), and the other being sildenafil, a candidate for drug repurposing in AD. The case studies further demonstrated the reliability and success of 3DSTarPred in practice. The 3DSTarPred server is freely available at http://3dstarpred.pumc.wecomput.com.

Research progress of Paris polyphylla in the treatment of digestive tract cancers

Cancer has become one of the most important causes of human death. In particular, the 5 year survival rate of patients with digestive tract cancer is low. Although chemotherapy drugs have a certain efficacy, they are highly toxic and prone to chemotherapy resistance. With the advancement of antitumor research, many natural drugs have gradually entered basic clinical research. They have low toxicity, few adverse reactions, and play an important synergistic role in the combined targeted therapy of radiotherapy and chemotherapy. A large number of studies have shown that the active components of Paris polyphylla (PPA), a common natural medicinal plant, can play an antitumor role in a variety of digestive tract cancers. In this paper, the main components of PPA such as polyphyllin, C21 steroids, sterols, and flavonoids, amongst others, are introduced, and the mechanisms of action and research progress of PPA and its active components in the treatment of various digestive tract cancers are reviewed and summarized. The main components of PPA have been thoroughly explored to provide more detailed references and innovative ideas for the further development and utilization of similar natural antitumor drugs.