As a terpenoids natural product isolated from the plant Thunder God Vine, Celastrol is widely studied for its pharmacological activities, including anti-tumor activities. The clinical application of Celastrol is strictly limited due to its severe side effects, whereas previously revealed targets and mechanism of Celastrol seldom reduce its in vivo toxicity via structural optimization. Target identification has a far-reaching influence on the development of innovative drugs, and omics data has been widely used for unbiased target prediction. However, it is difficult to enrich target of specific phenotype from thousands of genes or proteins, especially for natural products with broad promising activities. Here, we developed a text-mining-based web-server tool to enrich targets from omics data of inquired compounds. Then peroxiredoxin 1 (PRDX1) was identified as the ROS-manipulating target protein of Celastrol in colorectal cancer. Our solved high-resolution crystal structure revealed the unique covalent binding mode of Celastrol with PRDX1. New derivative compound 19-048 with improved potency against PRDX1 and selectivity towards PRDX2~PRDX6 were synthesized based on crystal structure analysis. Both Celastrol and 19-048 effectively suppressed the proliferation of colorectal cancer cells. The anti-tumor efficacy of Celastrol and 19-048 was significantly diminished on xenograft nude mice bearing PRDX1 knock-down colorectal cancer cells. Several downstream genes of p53 signaling pathway were dramatically up-regulated with Celastrol or 19-048 treatment. Our findings reveal that the side effects of Celastrol could be reduced via structural modification, and PRDX1 inhibition is promising for the treatment of colorectal cancer.
Reactive oxygen species exacerbate nonalcoholic steatohepatitis (NASH) by oxidizing macromolecules; yet how they promote NASH remains poorly understood. Here, we show that peroxidase activity of global hepatic peroxiredoxin (PRDX) is significantly decreased in NASH, and palmitic acid (PA) binds to PRDX1 and inhibits its peroxidase activity. Using three genetic models, we demonstrate that hepatic PRDX1 protects against NASH in male mice. Mechanistically, PRDX1 suppresses STAT signaling and protects mitochondrial function by scavenging hydrogen peroxide, and mitigating the oxidation of protein tyrosine phosphatases and lipid peroxidation. We further identify rosmarinic acid (RA) as a potent agonist of PRDX1. As revealed by the complex crystal structure, RA binds to PRDX1 and stabilizes its peroxidatic cysteine. RA alleviates NASH through specifically activating PRDX1’s peroxidase activity. Thus, beyond revealing the molecular mechanism underlying PA promoting oxidative stress and NASH, our study suggests that boosting PRDX1’s peroxidase activity is a promising intervention for treating NASH.
4 October 2016 in Current Protein & Peptide Science
As a family of chromatin remodeling proteins, metastasis-associated proteins (MTAs) have shown to be the master regulators in both physiological and pathological context. Although MTA3 is the latest being identified in MTA family, it has started to draw as much attention as the other family members. MTA3 is expressed in various tissues and is associated with different physiological functions. In cancerous context, both MTA1 and MTA2 are generally considered as oncogenes because they are capable of enhancing metastasis. However, MTA3 appears to play more complicated roles in cancers depending on the context. As a tumor suppressor, MTA3 usually down-regulates Snail, the master regulator of epithelium-mesenchymal transition, and subsequently represses cancer cell invasion and migration. Additionally, MTA3 may function by enhancing cancer cell differentiation without affecting proliferation in certain cancers. On the other hand, MTA3 might function in oncogencerelated properties similarly as MTA1 and MTA2. In this review, we summarize our current understanding about MTA3 in normal development, cancers as well as other human diseases by comparing the similarities and differences between MTA3 and the other members of the MTA family.
Breast cancer is one of the most common malignancies that threaten the health of women. Although there are a few chemotherapies for the clinical treatment of breast cancer, these therapies are faced with the problems of drug‑resistance and metastasis. Drug combination can help to reduce the adverse side effects of chemotherapies using single drugs, and also help to overcome common drug‑resistance during clinical treatment of breast cancer. The present study reported the synergistic effect of the heat shock protein 90 inhibitor 17‑AAG and the histone deacetylase 6 inhibitor Belinostat in triple‑negative breast cancer (TNBC) MDA‑MB‑231 cells, by detection of proliferation, apoptosis and cell cycle arrest following treatment with this combination. Subsequently, RNA sequencing (RNA‑seq) data was collected and analyzed to investigate the synergistic mechanism of this combination. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways revealed by RNA‑seq data analysis, a wound‑healing assay was used to investigate the effect of this combination on the migration of MDA‑MB‑231 cells. Compared with treatment with 17‑AAG or Belinostat alone, both the viability inhibition and apoptosis rate of MDA‑MB‑231 cells were significantly enhanced in the combination group. The combination index values were <1 in three concentration groups. Revealed by the RNA‑seq data analysis, the most significantly enriched KEGG pathways in the combination group were closely associated with cell migration. Based on these findings, the anti‑migration effect of this combination was investigated. It was revealed that the migration of MDA‑MB‑231 cells was significantly suppressed in the combination group compared with in the groups treated with 17‑AAG or Belinostat alone. In terms of specific genes, the mRNA expression levels of TEA domain family proteins were significantly decreased in the combination group, whereas the phosphorylation of YY1 associated protein 1 and modulator of VRAC current 1 was significantly enhanced in the combination group. These alterations may help to explain the anti‑migration effect of this combination. Belinostat has already been approved as a treatment for T‑cell lymphoma and 17‑AAG is undergoing clinical trials. These findings could provide a beneficial reference for the clinical treatment of patients with TNBC.