Synthesis and evaluation of pentacyclic triterpenoids conjugates as novel HBV entry inhibitors targeting NTCP receptor

Study on the activity of targeted delivery of DOX against melanoma by exosome-like nanovesicles of Rhodiola rosea

Melanoma is the main cause of death from skin cancer. The current treatment methods have prominent toxic side effects. In order to more effectively inhibit melanoma and reduce the toxic side effects during treatment, this paper constructs an engineering system using DSPE-PEG2000-pYEEIE(pYEEIE) molecules to modify exosome-like nanovesicles vesicles of Rhodiola rosea (RELNs) and load Doxorubicin (DOX). As a drug system, the aim is to achieve better targeting activity of the system towards melanoma cell A375. The results showed that the morphology and particle size of the prepared RELNs met the defined criteria for evaluating extracellular vesicles. The pYEEIE-RELNs-DOX drug delivery system has a better inhibitory effect on cell proliferation compared to DOX and RELNs-DOX. At the same time, the pYEEIE-RELN-DOX drug delivery system also showed better targeting towards tumor cells. In summary, this study proposes for the first time RELNs as a new generation of drug delivery carriers and uses them for drug delivery and inhibition of melanoma cell toxicity. This lays the foundation for subsequent animal and clinical experiments, and provides new ideas for the treatment of skin cancer caused by melanoma.

Discovery of pentacyclic triterpene conjugates as HBV polymerase/NTCP dual-targeting inhibitors with potent anti-HBV activities

The inhibition of HBV DNA and elimination of HBsAg has already been established as an indicator for HBV clinic cure, and a novel dual-targeting inhibitors of HBV polymerase/entry are designed and synthesized in this study. Pentacyclic triterpenes (PTs) scaffold of exhibiting a high affinity to NTCP, including glycyrrhitinic acid (GA), oleanolic acid (OA), ursolic acid (UA), and betulinic acid (BA) were linked neatly with the nucleoside drug zidovudine (AZT) through a molecular hybrid strategy to synthesize twenty of PTs-AZT conjugates for targeting HBV polymerase as well as sodium taurocholate cotransporting polypeptide (NTCP). The conjugates showed significant inhibitory effects on the secretion of HBsAg and HBeAg in HepG2.2.15 cells, and the activity on HBsAg were better. Moreover, HBV DNA replication was also notably suppressed after incubated with the conjugates. The IC50 value of BA-AZT1 on HBsAg inhibition was 0.65 ± 0.07 μM, and it was 284.2 times and 442.2 times higher comparing to corresponding parent compound BA and AZT. Additionally, the therapeutic index (TI) was also improved by 87.8 times than AZT. And the IC50 value of BA-AZT1 on inhibition of HBV DNA replication was 0.70 ± 0.02 μM, 10.4 times higher than that of AZT besides conspicuous TI. Molecular docking suggested that AZT skeleton of conjugate BA-AZT1 interacted with B region of HBV Polymerase reverse transcription region, and BA structure simultaneously targeted to C region of polymerase via hydrophobic chain, establishing strong binding interactions with the HBV Pol protein. In addition, docked with NTCP, BA-AZT1 with flat pentacyclic structure inserted into the interface and also formed hydrogen bonds, hydrophobic and van der Waals forces with the amino residue 157-165 of NTCP. Further SPR analysis demonstrated the binding affinity of BA-AZT1 to C region of polymerase was 19.55 μM, stronger than 53.21 μM of BA and 31.82 μM of AZT. BA-AZT1 selectively bound to the 157-165 epitopes of NTCP receptors in host cell but not PreS1 of virus. As a result, we deduced that the designed conjugates targeted NTCP and HBV polymerase, not only prevented HBV from entering host cells via selective binding NTCP, but also inhibited HBV DNA replication through obstructing the function of HBV polymerase, and it could potentially serve as a promising dual-functional and dual-target inhibitor with both replication and entry inhibition to exert anti-HBV activity.

Novel mechanistic insights - A brand new Era for anti-HBV drugs

Hepatitis B Virus (HBV) remains a critical global health issue, with substantial morbidity and mortality. Current therapies, including interferons and nucleoside analogs, often fail to achieve complete cure or functional eradication. This review explores recent advances in anti-HBV agents, focusing on their innovative mechanisms of action. HBV entry inhibitors target the sodium taurocholate cotransporting polypeptide (NTCP) receptor, impeding viral entry, while nucleus translocation inhibitors disrupt key viral life cycle steps, preventing replication. Capsid assembly modulators inhibit covalently closed circular DNA (cccDNA) formation, aiming to eradicate the persistent viral reservoir. Transcription inhibitors targeting cccDNA and integrated DNA offer significant potential to suppress HBV replication. Immunomodulatory agents are highlighted for their ability to enhance host immune responses, facil-itating better control and possible eradication of HBV. These novel approaches represent significant advancements in HBV therapy, providing new strategies to overcome current treatment limitations. The development of cccDNA reducers is particularly critical, as they directly target the persistent viral reservoir, offering a promising pathway towards achieving a functional cure or complete viral eradication. Continued research in this area is essential to advance the effectiveness of anti-HBV therapies.