Tambulin Targets Histone Deacetylase 1 Inhibiting Cell Growth and Inducing Apoptosis in Human Lung Squamous Cell Carcinoma

Advances in targeting histone deacetylase for treatment of solid tumors

Histone deacetylase (HDAC) serves as a critical molecular regulator in the pathobiology of various malignancies and have garnered attention as a viable target for therapeutic intervention. A variety of HDAC inhibitors (HDACis) have been developed to target HDACs. Many preclinical studies have conclusively demonstrated the antitumor effects of HDACis, whether used as monotherapy or in combination treatments. On this basis, researchers have conducted various clinical studies to evaluate the potential of selective and pan-HDACis in clinical settings. In our work, we extensively summarized and organized current clinical trials, providing a comprehensive overview of the current clinical advancements in targeting HDAC therapy. Furthermore, we engaged in discussions about several clinical trials that did not yield positive outcomes, analyzing the factors that led to their lack of anticipated therapeutic effectiveness. Apart from the experimental design factors, issues such as toxicological side effects, tumor heterogeneity, and unexpected off-target effects also contributed to these less-than-expected results. These challenges have naturally become significant barriers to the application of HDACis. Despite these challenges, we believe that advancements in HDACi research and improvements in combination therapies will pave the way or lead to a broad and hopeful future in the treatment of solid tumors.

Comprehensive metabolomic variations of hawthorn before and after insect infestation based on the combination analysis of 1H NMR and UPLC-MS

Hawthorn, the sliced and dried ripe fruits of Crataegus pinnatifida Bge. Var. Major N. E. Br. (Rosaceae), is an edible and medicinal substance with a variety of health-promoting benefits. Hawthorn needs to be stored in warehouses after harvesting to meet people's perennial demand. However, it is easily infested by insects of Plodia interpunctella and Tribolium castaneum during storage, which inevitably leads to poor quality and causes adverse effects on people's health. So far, there has been no report on insect-infested hawthorn. In this study, we analyzed the changes of metabolites in hawthorn before and after insect infestation and screened out potential biomarkers to effectively and quickly detect the occurrence of insect infestation. A combination analysis of 1H nuclear magnetic resonance (NMR) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to identify the primary and secondary metabolites. By the comparison of hawthorn and insect-infested hawthorn samples, it was found that the differences were mainly manifested in the content of metabolites. The metabolites of 32 and 1463 were identified by 1H NMR and UPLC-MS analysis, respectively. According to the parameters of VIP >1 and P < 0.05, 10 differential metabolites were screened from 1H NMR analysis. Based on the parameters of VIP >1.0, P < 0.05, and (FC) > 1 or < 1, 47 differential metabolites were screened from UPLC-MS analysis. Therefore, a total of 57 differential metabolites were considered as differential biomarkers. The heat map analysis showed that the content of some differential biomarkers with significant pharmacological activities decreased after insect infestation. Through receiver operating characteristic (ROC) curve assessment, 52 differential biomarkers (6 of 1H NMR analysis and 46 of UPLC-MS analysis) were screened to distinguish whether insect infestation occurred in hawthorn. This is the first report on the changes of metabolites between hawthorn and insect-infested hawthorn and on the screening of differential biomarkers for monitoring insects. These results contributed to evaluate quality of hawthorn and ensure food safety for consumers. It also laid a foundation for further research on the infestation mechanism and safe storage monitoring in hawthorn.

Eupalinolide O Induces Apoptosis in Human Triple-Negative Breast Cancer Cells via Modulating ROS Generation and Akt/p38 MAPK Signaling Pathway

Background

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with limited therapeutic options. Eupalinolide O (EO) was reported to inhibit tumor growth. This study is aimed at exploring the role of EO on TNBC both in vivo and in vitro. Methods. In in vitro experiments, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assay were conducted to measure the impact of EO on TNBC cell growth at different concentrations and time points. Flow cytometry was conducted to evaluate cell apoptosis. Mitochondrial membrane potential (MMP) loss, caspase-3 activity, and reactive oxygen species (ROS) generation were assessed. The expressions of apoptosis-related mRNAs and Akt/p38 MAPK signaling pathway-related proteins were measured. In in vivo experiments, by injecting TNBC cells into the nude mice to induce xenograft tumor, mice were treated with EO for 20 days. Then, in vivo bioluminescence imaging system was utilized to monitor the growth and distribution of TNBC cells. Tumor volume and weight were also recorded. Hematoxylin-eosin (HE) staining and ELISA assay were applied to observe tumor tissue morphology and ROS levels. Furthermore, western blotting was conducted to observe the expression of apoptosis-related proteins and Akt/p38 MAPK signaling pathway-associated proteins.

Results

EO inhibited the cell viability and proliferation of TNBC cells but not normal epithelial cells. Furthermore, EO induced apoptosis, decreased MMP, and elevated caspase-3 activity and ROS content in TNBC cells. Meanwhile, the expression of apoptosis-related mRNAs and Akt/p38 MAPK pathway-related proteins was regulated by EO treatment. Besides, in vivo experiments demonstrated EO not only suppressed tumor growth, Ki67 expression, ROS generation, and Akt phosphorylation but also upregulated caspase-3 expression and p-38 phosphorylation.

Conclusion

EO may induce cell apoptosis in TNBC via regulating ROS generation and Akt/p38 MAPK pathway, indicating EO may be a candidate drug for TNBC.

4-Hydroxyderricin Promotes Apoptosis and Cell Cycle Arrest through Regulating PI3K/AKT/mTOR Pathway in Hepatocellular Cells

4-hydroxyderricin (4-HD), as a natural flavonoid compound derived from Angelica keiskei, has largely unknown inhibition and mechanisms on liver cancer. Herein, we investigated the inhibitory effects of 4-HD on hepatocellular carcinoma (HCC) cells and clarified the potential mechanisms by exploring apoptosis and cell cycle arrest mediated via the PI3K/AKT/mTOR signaling pathway. Our results show that 4-HD treatment dramatically decreased the survival rate and activities of HepG2 and Huh7 cells. The protein expressions of apoptosis-related genes significantly increased, while those related to the cell cycle were decreased by 4-HD. 4-HD also down-regulated PI3K, p-PI3K, p-AKT, and p-mTOR protein expression. Moreover, PI3K inhibitor (LY294002) enhanced the promoting effect of 4-HD on apoptosis and cell cycle arrest in HCC cells. Consequently, we demonstrate that 4-HD can suppress the proliferation of HCC cells by promoting the PI3K/AKT/mTOR signaling pathway mediated apoptosis and cell cycle arrest.

Renoprotective effects of levosimendan on acute kidney injury following cardiac arrest via anti-inflammation, anti-apoptosis, and ERK activation

ATP‐sensitive potassium channels (KATPs) have protective effects in ischemia–reperfusion‐induced injuries and can be activated by levosimendan. This study investigated the effects of levosimendan on renal injury, inflammation, apoptosis, and survival in a rat model of acute kidney injury (AKI) following cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). Rats underwent a 5‐min asphyxia‐based CA and resuscitation. The rats were treated with levosimendan after successful resuscitation. Renal functions, histological changes, inflammatory responses, and apoptosis were examined. NRK‐52E cells treated by hypoxia/reoxygenation (H/R) were used to establish an in vitro CA‐CPR model. Rats in the CA‐induced AKI group had a low survival rate and increased levels of creatinine, blood urea nitrogen, and proinflammatory cytokines, as well as increased tubular injury. These results were significantly reversed after treatment with levosimendan. Levosimendan downregulated the expression of the apoptosis‐related proteins Bax, cleaved caspase‐3, and cleaved caspase‐9, as well as upregulated Bcl‐2 and p‐ERK expression in vivo and in vitro. Thus, our data suggest that levosimendan reduces mortality and AKI following CA and CPR via suppression of inflammation and apoptosis, and activation of ERK signaling.

Restoring microRNA-499-5p Protects Sepsis-Induced Lung Injury Mice Via Targeting Sox6

BACKGROUND

MicroRNAs (miRs) are known to participate in sepsis; hence, we aim to discuss the protective effect of miR-499-5p targeting sex-determining region Y-related high-mobility-group box 6 (Sox6) on sepsis-induced lung injury in mice.

METHODS

The sepsis-induced lung injury model was established by cecal ligation and puncture. The wet/dry weight (W/D) ratio, miR-499-5p, Sox6, Caspase-3 and Caspase-9 expression in lung tissues of mice were tested. Lung injury score, collagen fibers and the degree of pulmonary fibrosis in lung tissues were determined. Further, the cell apoptosis in lung tissues was measured. The inflammatory factors contents and oxidative stress indices in bronchoalveolar lavage fluid (BALF) and lung tissues were detected via loss- and gain-of-function assays. The targeting relation between miR-499-5p and Sox6 was verified.

RESULTS

W/D ratio and Sox6 were increased while miR-499-5p was decreased in lung tissues of sepsis-induced lung injury mice. Restored miR-499-5p or depleted Sox6 alleviated lung tissues pathology, reduced lung injury score, collagen fibers, the degree of pulmonary fibrosis, TUNEL positive cells, Caspase-3 and Caspase-9 protein expression and inflammatory factors contents in BALF and lung tissues as well as oxidative stress response in lung tissues of sepsis-induced lung injury mice. miR-499-5p targeted Sox6.

CONCLUSION

High expression of miR-499-5p can attenuate cell apoptosis in lung tissues and inhibit inflammation of sepsis-induced lung injury mice via depleting Sox6, and it is a potential candidate marker and therapeutic target for sepsis-induced lung injury.

Identification of potential histone deacetylase inhibitory biflavonoids from Garcinia kola (Guttiferae) using in silico protein-ligand interaction

Overactivity of histone deacetylases (HDACs) is the underlying cause of some cancers, thus, inhibiting their overactivities is a rational treatment option. However, endeavors to employ current anti-HDACs agents in cancer treatment have yielded limited success. Consequently, there is need to explore anti-HDACs natural products, especially from plants sources, because of the intimate relationship plant products and drug discovery have enjoyed over the centuries. To identify possible HDACs inhibitors, Garcinia kola (Guttiferae) seed-derived compounds were screened in silico for HDAC-inhibitory tendencies because of their reported anticancer potentials. Fifteen G. kola-derived compounds and givinostat were docked with five selected HDACs using AutodockVina, while the binding interactions of the compounds with high binding affinities for the five HDACs were viewed with Discovery Studio Visualizer BIOVIA, 2016. Results indicated that four of the compounds studied, including amentoflavone, Garcinia biflavonoid 1, Garcinia biflavonoid 2 and kolaflavanone have higher binding propensity for all the five HDACs relative to givinostat, the standard HDAC inhibitor. This study indicated that inhibition of HDAC might be another key mechanism accountable for the bioactivities of G. kola and its intrinsic compounds. The results from this study implied that the compounds could be further investigated as drugable HDAC inhibitors with potential pharmacological applications in the treatment of cancers.

Epigenetic modulation and understanding of HDAC inhibitors in cancer therapy

The role of genetic and epigenetic factors in tumor initiation and progression is well documented. Histone deacetylases (HDACs), histone methyl transferases (HMTs), and DNA methyl transferases. (DNMTs) are the main proteins that are involved in regulating the chromatin conformation. Among these, histone deacetylases (HDAC) deacetylate the histone and induce gene repression thereby leading to cancer. In contrast, histone acetyl transferases (HATs) that include GCN5, p300/CBP, PCAF, Tip 60 acetylate the histones. HDAC inhibitors are potent drug molecules that can induce acetylation of histones at lysine residues and induce open chromatin conformation at tumor suppressor gene loci and thus resulting in tumor suppression. The key processes regulated by HDAC inhibitors include cell-cycle arrest, chemo-sensitization, apoptosis induction, upregulation of tumor suppressors. Even though FDA approved drugs are confined mainly to haematological malignancies, the research on HDAC inhibitors in glioblastoma multiforme and triple negative breast cancer (TNBC) are providing positive results. Thus, several combinations of HDAC inhibitors along with DNA methyl transferase inhibitors and histone methyl transferase inhibitors are in clinical trials. This review focuses on how HDAC inhibitors regulate the expression of coding and non-coding genes with specific emphasis on their anti-cancer potential.