Current Molecular Pharmacology - Current Issue

Disease relapse and therapy resistance remain serious impediments to treating cancer. Leukemia stem cells (LSC) are therapy resistant and the cause of relapse. A state of deep quiescence appears to enable cancer stem cells (CSC) to acquire new somatic mutations essential for disease progression and therapy resistance. Both normal hematopoietic stem cells (HSC) and LSC share many common features, thereby complicating the safe elimination of LSC. A recent study demonstrated that long lived normal oocytes exist without mitochondrial complex I (MC-1), expressing it in a developmentally regulated fashion, thereby mitigating their vulnerability to ROS. Quiescent CSC rely on mitochondrial FAO, without complex I expression, thereby avoiding the generation of damaging ROS, similar to long lived normal human stem cells. A deeper understanding of the biology of therapy resistance is important for the development of optimal strategies to attain complete leukemia cures.

Here, using scRNA-sequencing and ATAC-seq on primary chronic myelogenous leukemia (CML) patient samples, combined with bioinformatics analyses, we further examine the heterogeneity of a previously characterized in vitro imatinib-selected CD34^-CD38^- CML LSC population. We utilized a series of functional analyses, including single-cell metabolomic and Seahorse analyses, to validate the existence of the deepest quiescent leukemia initiators (LI) subset.

Current study revealed heterogeneity of therapy resistant LSC in CML patients and their existence of two functionally distinct states. The most deeply quiescent LI suppress the expression of MC-1, yet are highly dependent on fatty acid oxidation (FAO) for their metabolic requirements and ATAC-seq demonstrated increased chromatin accessibility in this population, all consistent with an extremely primitive, quiescent stemness transcriptional signature. Importantly, the specific CREB binding protein (CBP)/β-catenin antagonist ICG-001 initiates the differentiation of LSC, including LI, decreases chromatin accessibility with differentiation and increasing expression of MC-1, CD34, CD38 and BCR-ABL1, thereby re-sensitizing them to imatinib.

We investigated the biological aspects related to LSC heterogeneity in CML patients and demonstrated the ability of specific small molecule CBP/β-catenin antagonists to safely eliminate deeply quiescent therapy resistant CSC. These observations may represent an attractive generalizable therapeutic strategy that could help develop better protocols to eradicate the quiescent LSC population.

Psoriasis is an acute to chronic multifunctional inflammatory skin disorder mediated through T-cell activation, dendritic cell intervention, local vascular variations, atypical keratinocyte proliferation, and neutrophil activation, leading to a skin disorder with no permanent cure.

This review aims to find a potent, secure, and dependable medication, with a more scientific examination of herbal resources and recent targeted immunobiological therapies.

Reports evaluating the effectiveness of biologics & herbal remedies for the topical therapy of psoriasis against control therapies were taken into consideration (placebo or active therapy). The work examined cellular circuits involved in inflammation with its immunogenetic mechanism behind various options available for treating psoriasis in addition to the role of agents inducing psoriasis.

The extent of psoriasis can range from small, localized spots to total body coverage, and it can happen at any stage of life. Several theories exist for clarification however, the exact cause of psoriasis is not entirely understood. Researchers have discovered genetic loci linkages, environmental changes, drug induction, lifestyle conditions, some infections, etc. resulting in this disorder. There are numerous known conventional medical treatments for psoriasis, ranging from topical and systemic medicines to phototherapy or combinations of both with recent immunobiological treatment. However, the majority of these treatments are ineffective and have a variety of side effects that limit their long-term usage, such as cutaneous atrophy, tissue toxicity, mutagenicity, and immunosuppression.

Herbal extracts or isolated compounds can be considered as a substitute for conventional psoriasis treatment. Unfortunately, many investigations often provide a small amount of facts about the safety and effectiveness of topically applied herbal remedies for the treatment of psoriasis. Thus, further factual evidences and validations are needed to promote herbal options, which must be supported by rigorous animal studies or clinical trials using standardised materials and compositions.

The study aimed to investigate the effects of low concentrations of mitochondrial uncouplers in endothelial cells on the CpG dinucleotide methylation of the ICAM1 gene promoter. The excessive inflammatory response in the endothelium is responsible for the development of many cardiovascular diseases. Mitochondria are important regulators of endothelial cell functions. Mild uncoupling of oxidative phosphorylation and respiration in endothelial mitochondria exerts a long lasting anti-inflammatory effect. However, the detailed mechanism of the anti-inflammatory activity of mitochondrial uncouplers remains unclear.We hypothesized that mild mitochondrial uncoupling leads to epigenetic changes in genomic DNA contributing to the anti-inflammatory response.

We studied the long-term effects of mitochondria-targeted compounds with the uncoupler’s activities: the antioxidant plastoquinonyl-decyl-triphenylphosphonium (SkQ1), dodecyl-triphenylphosphonium (C12TPP), and 2,4-dinitrophenol (DNP). The mRNA expression of the intercellular adhesion molecule 1 (ICAM1), a marker of inflammatory activation of endothelial cells, was measured by RT-qPCR. Cytosine methylation in the CpG sites of the ICAM1 gene promoter was estimated by bisulfite sequencing of individual clones.

It was found that downregulation of ICAM1 expression caused by DNP and C12TPP was accompanied by an increase in the methylation of CpG sites in the ICAM1 gene promoter. None of the compounds affected intracellular or intramitochondrial ATP levels.

Low concentrations of mitochondrial oxidative phosphorylation uncouplers are able to increase methylation of ICAM1 gene promoter, which corresponds to the observed decrease in the levels of mRNA of this gene. Thus, the change in methylation of the ICAM1 gene promoter may underlie the mechanism of decreased ICAM1 expression caused by mild mitochondrial depolarization. Mitochondrial uncouplers may be exploited as possible therapeutic candidates to treat excessive inflammation in endothelium, by changing the methylation status of genomic DNA.

Glucoregulatory protein 94 (Grp94) is necessary for the post-viral life cycle and plays a quality control role in viral proteins, but the role of Grp94 in regulating viral replication in host cells is not well known. Therefore, finding a compound that can regulate Grp94 will help us to study the mechanism of viral replication. Previously, we synthesized a coumarin pyrazoline derivative HCP1 that is an effective inhibitor of Grp94. We suppose that HCP1 may inhibit viral replication.

This study aimed to investigate the effect of HCP1 on the replication ability of Senecavirus A (SVA), so as to provide a target and a leading compound for revealing the pathogenic mechanism of the virus and developing antiviral drugs.

Rat cell lines BHK-21 and porcine cell lines PK-15 were infected with SVA, and the infected cells were treated with different concentrations of HCP1. The cell viability (CCK-8), virus titer (TCID50), autophagy level, and Grp94 expression were measured.

The results showed that a low concentration of HCP1 decreased viral titer and viral load in BHK-21 and PK-15 cells, and 5μM HCP1 significantly decreased the expression of SVA VP2 protein. In addition, SVA infection can lead to an increased level of autophagy, and HCP1 can inhibit host cell autophagy caused by SVA infection, thereby inhibiting viral replication and infection.

These findings reveal that Grp94 is a key factor in controlling SVA replication, and its inhibitor HCP1 suppresses SVA replication by inhibiting the increase of Grp94 protein level and autophagy induced by SVA. This study will contribute to the development of a new class of small-molecule antiviral drugs.

Our previous work has demonstrated significant effects on the oxidative stress response, mitochondrial function, and oxidative phosphorylation in the livers and intestines of p300 S89A knockin (S89AKI) mice. We now show that this mutation is also associated with brain metabolic defects and neuronal differentiation.

p300 S89A edited P19 cells, and S89AKI mice demonstrated metabolic and neuronal differentiation defects based on proteomic, cell biological and PET imaging studies.

The metabolic and differentiation defects associated with the p300 S89A knockin mutation could be corrected both in vitro and in vivo utilizing the small molecule CBP/beta-catenin antagonist ICG-001.

Rebalancing the equilibrium between CBP/β-catenin versus p300/β-catenin associated transcription, utilizing the small molecule CBP/beta-catenin antagonist ICG-001, enhances mitochondrial oxidative phosphorylation, metabolic function, and neuronal differentiation and may be able to ameliorate the cognitive decline seen in neurodegenerative disorders, including Alzheimer’s Disease.

Physalin B (PB) is one of the main active compounds of Solanaceae plants, with a wide range of biological activities. PB reportedly has the potential to treat Alzheimer’s disease (AD).

In this study, we investigated the effect of PB on Tau phosphorylation and cell apoptosis using Tau-expressing HEK293 cells (HEK293/Tau) as a cellular model.

The optimum concentration of PB to treat HEK293/Tau cells was determined using the CCK-8 assay. Additionally, the expression of FoxO1, Tau-5, p-Tau (T231, S262, and S404), ERK, p-ERK, GSK-3β, and p-GSK-3β was detected using western blotting to determine the effect of PB on Tau phosphorylation. The apoptosis rate was detected using flow cytometry, and the expression of Bax and Bcl-2 was detected using western blotting and verified using real-time quantitative polymerase chain reaction (RT-qPCR). Moreover, cells were transfected with FoxO1 siRNA to downregulate FoxO1 expression, and the expression of the above-mentioned proteins was detected to verify the effect of PB on Tau phosphorylation and cell apoptosis.

After 24 h of PB treatment, the phosphorylation levels of Tau at S404, S262, and T231 sites decreased significantly, and the activities of GSK-3β and ERK were inhibited. PB also reduced cell apoptosis by reducing the expression of Bax and increasing the expression of Bcl-2. In addition, PB decreased Tau phosphorylation and cell apoptosis by upregulating FoxO1.

The natural compound PB exhibited a protective effect in the AD cell model by increasing FoxO1 expression and reducing Tau phosphorylation and cell apoptosis.

Liver fibrosis is associated with the activation of hepatic stellate cells (HSCs). Inhibition of HSCs activation is a strategy for alleviating hepatic fibrogenesis. CD73 is involved in liver disease development, while the mechanism remains unclear.

This study aimed to investigate the effect of CD73 targeting inhibition on liver fibrosis.

Intraperitoneal injection of CCl4 was used to induce liver fibrosis in mice models. Adenosine 5′-(α, β-methylene) diphosphate sodium salt (APCP) was used for CD73 blockade. The siRNA was used to induce CD73 knockdown in HSCs. LX2 and HSC-T6 were used to investigate the role of CD73 in HSCs activation in vitro.

The results showed that APCP treatment could alleviate hepatic fibrosis. In fibrotic liver tissues, CD73 exhibited a positive correlation with markers of HSCs activation. Furthermore, APCP treatment and CD73 knockdown could inhibit HSCs (LX2 and HSC-T6) activation and proliferation. By using RNA sequencing of liver tissues from control, CCl4-mice, and APCP-treated mice, 851 genes that were significantly changed in CCl4 mice (vs. control) were reversed by APCP treatment. These genes were mainly enriched in cell division-associated biological processes. Moreover, we found that CD73 might be associated with autophagy in HSCs. In fibrotic liver tissues and HSCs, ATG5 and Beclin1 expression could be downregulated by CD73 knockdown and APCP treatment.

This study demonstrated the effects and mechanism of CD73 in HSCs activation and proliferation, which presents the therapeutical potential of CD73 blockage for liver fibrosis.

Esophageal carcinoma (ESCA) is a common malignancy characterized by high morbidity and mortality. Our work managed to dissect the modulatory mechanism of E2F1/miR-29c-3p/COL11A1 in the malignant progression and sensitivity of ESCA cells to sorafenib.

Via bioinformatics approaches, we identified the target miRNA. Subsequently, CCK-8, cell cycle analysis, and flow cytometry were used to check the biological influences of miR-29c-3p on ESCA cells. TransmiR, mirDIP, miRPathDB, and miRDB databases were used as tools for the prediction of upstream transcription factors and downstream genes of miR-29c-3p. The targeting relationship of genes was detected via RNA immunoprecipitation and chromatin immunoprecipitation, which was further validated by dual-luciferase assay. Finally, in vitro experiments revealed the way E2F1/miR-29c-3p/COL11A1 affected sorafenib’s sensitivity, and in vivo experiments were used to verify the way E2F1 and sorafenib impacted ESCA tumor growth.

miR-29c-3p, downregulated in ESCA, could suppress ESCA cell viability, arrest the cell cycle in the G0/G1 phase, and impel apoptosis. E2F1 was found to be upregulated in ESCA and it could abate the transcriptional activity of miR-29c-3p. COL11A1 was found to be a downstream target of miR-29c-3p to enhance cell viability, induce cell cycle arrest in S phase, and constrain apoptosis. Cellular and animal experiments together demonstrated that E2F1 abated the sorafenib’s sensitivity of ESCA cells via miR-29c-3p/COL11A1.

E2F1 affected the viability, cell cycle, and apoptosis of ESCA cells by modulating miR-29c-3p/COL11A1, and it attenuated the sensitivity of ESCA cells to sorafenib, shedding new light on the treatment of ESCA.

The mammalian role of the rapamycin (mTOR) pathway is the practical nutrient-sensitive regulation of animal growth and plays a central role in physiology, metabolism, and common diseases. The mTOR is activated in response to nutrients, growth factors, and cellular energy. The mTOR pathway activates in various cellular processes and human cancer diseases. Dysfunction of mTOR signal transduction is associated with metabolic disorders, cancer for instance.

In recent years, significant achievements envisaged in developing targeted drugs for cancer. The global impact of cancer continues to grow. However, the focus of disease-modifying therapies remains elusive. The mTOR is a significant target in cancer to be considered for mTOR inhibitors, even though the costs are high. Despite many mTOR inhibitors, potent, selective inhibitors for mTOR are still limited. Therefore, in this review, the mTOR structure and protein-ligand interactions of utmost importance to provide the basis for molecular modelling and structure-based drug design are discussed.

This review introduces the mTOR, its crystal structure, and the latest research on mTOR.Besides, the role of mTOR in cancer, its function, and its regulation are reviewed. In addition, the mechanistic role of mTOR signalling networks in cancer and interaction with drugs that inhibit the development of mTOR and crystal structures of mTOR and its complexes are explored. Finally, the current status and prospects of mTOR-targeted therapy are addressed.

The first clinically evaluated CBP/β-catenin antagonist, PRI-724, displayed an excellent safety profile administered intravenously via continuous infusion. Eisai recently disclosed a third-generation, orally available, reportedly CBP/β-catenin antagonist, E7386. However, several structural features and the reported cytotoxicity of E7386 were unexpected for a specific CBP/β-catenin antagonist. Therefore, we undertook a comparison of E7386 versus the highly specific bona fide CBP/β-catenin antagonists, ICG-001 and C82, the active agents derived from the prodrug PRI-724.

CBP/β-catenin antagonists rebalance the equilibrium between CBP/β-catenin and p300/β-catenin dependent transcription and may be able to treat or prevent many diseases of aging via maintenance of somatic stem cell pool and regulating mitochondrial function and metabolism involved in differentiation and immune cell function. The safety, efficacy, and therapeutic potential of the specific CBP/β-catenin antagonists, ICG-001, and the second-generation compound, C82, the active agent derived from the pro-drug PRI-724, have been studied extensively in a variety of preclinical disease models and in the clinic for oncology and hepatic fibrosis. However, the lack of oral bioavailability has hampered the further development of PRI-724. Thus, Eisai recently proposed a third-generation, orally available, reportedly CBP/β-catenin antagonist E7386. Here, we have performed a comparative analysis of E7386 with the highly specific bona fide CBP/β-catenin antagonists, ICG-001 and C82.

We utilized a series of previously validated biochemical and transcriptional assays to investigate the selective targeting of the CBP/β-catenin interaction in conjunction with global transcriptional profiling to compare the three small molecules, ICG-001, C82, and E7386.

Our data cast significant doubt that the mechanism of action of E7386 is via specific CBP/β-catenin antagonism.

It can thus be concluded that E7386 is not a specific CBP/β-catenin antagonist.