Dihydrocelastrol induces cell death and suppresses angiogenesis through BCR/AP-1/junb signalling in diffuse large B cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. Although treatment options have improved, a large proportion of patients show low survival rates, highlighting an urgent need for novel therapeutic strategies. The aim of this study was to investigate the efficacy of the new small-molecule compound dihydrocelastrol (DHCE), acquired through the structural modification of celastrol (CE), in the treatment of DLBCL. DHCE showed potent anti-lymphoma efficacy and synergistic effects with doxorubicin. DHCE triggered DLBCL cell apoptosis and G0/G1-phase blockade, thereby hindering angiogenesis. DHCE inhibited B-cell receptor cascade signalling and Jun B and p65 nuclear translocation, thereby suppressing pro-tumourigenic signalling. Finally, DHCE exerted lower toxicity than CE, which showed severe hepatic, renal, and reproductive toxicity in vivo. Our findings support further investigation of the clinical efficacy of DHCE against DLBCL.

Dihydrocelastrol induces antitumor activity and enhances the sensitivity of bortezomib in resistant multiple myeloma by inhibiting STAT3-dependent PSMB5 regulation.

Multiple myeloma (MM) is characterized by excessive aggregation of B-cell-derived malignant plasma cells in the hematopoietic system of bone marrow. Previously, we synthesized an innovative molecule named dihydrocelastrol (DHCE) from celastrol, a triterpene purified from medicinal plant Tripterygium wilfordii. Herein, we explore the therapeutic properties and latent signal transduction mechanism of DHCE action in bortezomib (BTZ)-resistant (BTZ-R) MM cells. In this study, we first report that DHCE shows antitumor activities in vitro and in vivo and exerts stronger inhibitory effects than celastrol on BTZ-R cells. We find that DHCE inhibits BTZ-R cell viability by promoting apoptosis via extrinsic and intrinsic pathways and suppresses BTZ-R MM cell proliferation by inducing G0/G1 phase cell cycle arrest. In addition, inactivation of JAK2/STAT3 and PI3K/Akt pathways are involved in the DHCE-mediated antitumor effect. Simultaneously, DHCE acts synergistically with BTZ on BTZ-R cells. PSMB5, a molecular target of BTZ, is overexpressed in BTZ-R MM cells compared with BTZ-S MM cells and is demonstrated to be a target of STAT3. Moreover, DHCE downregulates PSMB5 overexpression in BTZ-R MM cells, which illustrates that DHCE overcomes BTZ resistance through increasing the sensitivity of BTZ in resistant MM via inhibiting STAT3-dependent PSMB5 regulation. Overall, our findings imply that DHCE may become a potential therapeutic option that warrants clinical evaluation for BTZ-R MM.

The effectiveness of anti-biofilm and anti-virulence properties of dihydrocelastrol and dihydrocelastryl diacetate in fighting against methicillin-resistant Staphylococcus aureus.

Human pathogens have readily been converted into multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), because of the long-term use of conventional antibiotics. In addition, the biofilms formed by S. aureus cells are especially problematic and are related to the persistence of chronic infections because they constitute a major mechanism of promoting tolerance to diverse antimicrobial agents. Hence, the inhibitions of biofilm formation and/or toxin production are accepted as alternative means of controlling S. aureus infections. The present study was aimed at identifying novel anti-biofilm and/or anti-virulence compounds in friedelane-based pentacyclic triterpenoids present in many edible and medicinal plants-and investigating them against MRSA strains. As a result, dihydrocelastrol and dihydrocelastryl diacetate were found to both inhibit the biofilm formation of, and to disrupt the preformed biofilms of, MRSA strains to an increasingly greater degree with increasing concentrations of each compound. Furthermore, these two triterpenoids also clearly inhibited the hemolytic activity of MRSA-and in-line with their anti-biofilm activities, rendered the cell more hydrophilic. Additionally, corroborating phenotypic results, transcriptional analyses showed that both dihydrocelastrol and dihydrocelastryl diacetate disturbed the expression of gene related to α-hemolysin (hla) and down-regulated the expressions of the crucial biofilm-associated genes (agrA, sarA, ica, RNAIII, and rbf) in MRSA. The findings of this study suggest that friedelane-based pentacyclic triterpenoids-especially dihydrocelastrol and dihydrocelastryl diacetate-have the potential to be candidates both for use in controlling biofilm-related infections and for use as important components of anti-virulence strategies for fighting against MRSA infection.

Dihydrocelastrol inhibits multiple myeloma cell proliferation and promotes apoptosis through ERK1/2 and IL-6/STAT3 pathways in vitro and in vivo.

Multiple myeloma (MM) is the second most frequent malignant hematological disease. Dihydrocelastrol (DHCE) is synthesized by hydrogenated celastrol, a treterpene isolated from Chinese medicinal plant Tripterygium regelii. In this study, we first reported the anti-tumor activity of DHCE on MM cells. We found that DHCE could inhibit cell proliferation and promote apoptosis through caspase-dependent way in vitro. In addition, DHCE could inactivate the expression of interleukin (IL)-6 and downregulate the phosphorylation of extracellular regulated protein kinases (ERK1/2) and the signal transducer and activator of transcription 3 (STAT3) in MM. It also retained its activity against MM cell lines in the presence of IL-6. Furthermore, treatment of MM cells with DHCE resulted in an accumulation of cells in G0/G1 phase of the cell cycle. Notably, DHCE reduced the expression of cyclin D1 and cyclin-dependent kinases 4 and 6 in MM cell lines. Additionally, its efficacy toward the MM cell lines could be enhanced in combination with the histone deacetylase inhibitor panobinostat (LBH589), which implied the possibility of the combination treatment of DHCE and LBH589 as a potential therapeutic strategy in MM. In addition, treatment of NCI-H929 tumor-bearing nude mice with DHCE (10 mg/kg/d, i.p., 1-14 days) resulted in 73% inhibition of the tumor growth in vivo. Taken together, the results of our present study indicated that DHCE could inhibit cellular proliferation and induce cell apoptosis in myeloma cells mediated through different mechanisms, possibly through inhibiting the IL-6/STAT3 and ERK1/2 pathways. And it may provide a new therapeutic option for MM patients.