Soloxolone methyl inhibits influenza virus replication and reduces virus-induced lung inflammation

Recent Efforts in Identification of Privileged Scaffolds as Antiviral Agents

Viral infections are the most important health concern nowadays to mankind, which is unexpectedly increasing the health complications and fatality rate worldwide. The recent viral infection outbreak developed a pressing need for small molecules that can be quickly deployed for the control/treatment of re-emerging or new emerging viral infections. Numerous viruses, including the human immunodeficiency virus (HIV), hepatitis, influenza, SARS-CoV-1, SARS-CoV-2, and others, are still challenging due to emerging resistance to known drugs. Therefore, there is always a need to search for new antiviral small molecules that can combat viral infection with new modes of action. This review highlighted recent progress in developing new antiviral molecules based on natural product-inspired scaffolds. Herein, the structure-activity relationship of the FDA-approved drugs along with the molecular docking studies of selected compounds have been discussed against several target proteins. The findings of new small molecules as neuraminidase inhibitors, other than known drug scaffolds, Anti-HIV and SARS-CoV are incorporated in this review paper.

Soloxolone methyl induces apoptosis and oxidative/ER stress in breast cancer cells and target cancer stem cell population

One of the most prevalent malignancies in women and one of the leading causes of cancer-related death is breast cancer. There is a need for new treatment approaches and drugs for breast cancer. Many studies show the high potential of triterpene compounds and their semisynthetic derivatives as anticancer agents due to their ability to induce apoptosis and suppress tumorigenesis. The effects of soloxolone methyl (SM), a semisynthetic derivative of 18-H-glycyrrhetinic acid, on the cytotoxicity and apoptosis of human breast cancer cell line (T-47D) and cancer stem cell (CSCs) population (mammospheres; CD44+/CD24-antigen) derived from breast cancer cells, were examined in this work. The ATP assay was used to determine SM growth-inhibitory effects. Fluorescent staining, caspase-cleaved cytokeratin 18, and flow cytometry analysis were used to determine the mode of the cell death. In addition, cell death was investigated at protein and gene levels by Western Blotting and PCR, respectively. SM resulted in cytotoxicity in a time and dose dependent manner via ROS production and ER stress in T-47D cells in 2 models. The mode of cell death was apoptosis, evidenced by phosphatidylserine exposure, caspase activation, and bax overexpression. In mammospheres as 3D model, SM decreased stem cell properties and induced cell death. Taken together, SM may be a promising agent in the treatment of breast cancer, especially due to its antigrowth activity on CSCs.

Protective effect of soloxolone derivatives in carrageenan- and LPS-driven acute inflammation: Pharmacological profiling and their effects on key inflammation-related processes

The anti-inflammatory potential of three cyanoenone-containing triterpenoids, including soloxolone methyl (SM), soloxolone (S) and its novel derivative bearing at the C-30 amidoxime moiety (SAO), was studied in murine models of acute inflammation. It was found that the compounds effectively suppressed the development of carrageenan-induced paw edema and peritonitis as well as lipopolysaccharide (LPS)-driven acute lung injury (ALI) with therapeutic outcomes comparable with that of the reference drugs indomethacin and dexamethasone. Non-immunogenic carrageenan-stimulated inflammation was more sensitive to the transformation of C-30 of SM compared with immunogenic LPS-induced inflammation: the anti-inflammatory properties of the studied compounds against carrageenan-induced paw edema and peritonitis decreased in the order of SAO > S > > SM, whereas the efficiency of these triterpenoids against LPS-driven ALI was similar (SAO ≈ S ≈ SM). Further studies demonstrated that soloxolone derivatives significantly inhibited a range of immune-related processes, including granulocyte influx and the expression of key pro-inflammatory cytokines and chemokines in the inflamed sites as well as the functional activity of macrophages. Moreover, SM was found to prevent inflammation-associated apoptosis of A549 pneumocytes and effectively inhibited the protease activity of thrombin (IC₅₀ = 10.3 µM) tightly associated with rodent inflammatome. Taken together, our findings demonstrate that soloxolone derivatives can be considered as novel promising anti-inflammatory drug candidates with multi-targeted mechanism of action.

Potential of glycyrrhizic and glycyrrhetinic acids against influenza type A and B viruses: A perspective to develop new anti-influenza compounds and drug delivery systems

Despite the recent dynamic development of medicine, influenza is still a significant epidemiological problem for people around the world. The growing resistance of influenza viruses to currently available antiviral drugs makes it necessary to search for new compounds or drug forms with potential high efficacy against human influenza A and B viruses. One of the methods of obtaining new active compounds is to chemically modify privileged structures occurring in the natural environment. The second solution, that is gaining more and more interest, is the use of modern drug carriers, which significantly improve physicochemical and pharmacokinetic parameters of the transported substances. Molecules known from the earliest times for their numerous therapeutic properties are glycyrrhizinic acid (GA) and glycyrrhetinic acid (GE). Both compounds constitute the main active agents of the licorice (Glycyrrhiza glabra, Leguminosae) root and, according to a number of scientific reports, show antiviral properties against both DNA and RNA viruses. The above information prompted many scientific teams around the world to obtain and test in vitro and/or in vivo new synthetic GA and GE derivatives against influenza A and B viruses. Similarly, in recent years, a significant amount of GA and GE-based drug delivery systems (DDS) such as nanoparticles, micelles, liposomes, nanocrystals, and carbon dots has been prepared and tested for antiviral activity, including those against influenza A and B viruses. This work systematizes the attempts undertaken to study the antiviral activity of new GA and GE analogs and modern DDS against clinically significant human influenza viruses, at the same time indicating the directions of their further development.

Assembly of Poly(ethylene glycol)ylated Oleanolic Acid on a Linear Polymer as a Pseudomucin for Influenza Virus Inhibition and Adsorption

Biomimicry of the mucin barrier function is an efficient strategy to counteract influenza. We report the simple aminolyzation of poly(methyl vinyl ether-alt-maleic anhydride) (PM) using amine-terminated poly(ethylene glycol)ylated oleanolic acid (OAPEG) to mimic the mucin structure and its adsorption of the influenza virus. Direct interactions between influenza hemagglutinin (HA) and the prepared macromolecule evaluated by surface plasmon resonance and isothermal titration calorimetry demonstrated that the multivalent presentation of OAPEG on PM enhanced the binding affinity to HA with a decrease in K_D of approximately three orders of magnitude compared with monomeric OAPEG. Moreover, hemagglutination inhibition assay, viral growth inhibition assay, and cytopathic effect reduction assay indicated that the nonglycosylated polymer could mimic natural heavily glycosylated mucin and thus promote the attachment of the virus in a subnanomolar range. Further investigation of the antiviral effects via time-of-addition assay, dynamic light scattering experiments, and transmission electron microscopy photographs indicated that the pseudomucin could adsorb the virion particles and synergistically inhibit the early attachment and final release steps of the influenza infection cycle. These findings demonstrate the effectiveness of the macromolecule in the physical sequestration and prevention of viral infection. Notably, due to its structural similarities with mucin, the biomacropolymer also has the potential for the rational design of antiviral drugs, influenza adsorbents, or filtration materials and the construction of model systems to explore protection against other pathogenic viruses.

Novel Epoxides of Soloxolone Methyl: An Effect of the Formation of Oxirane Ring and Stereoisomerism on Cytotoxic Profile, Anti-Metastatic and Anti-Inflammatory Activities In Vitro and In Vivo

It is known that epoxide-bearing compounds display pronounced pharmacological activities, and the epoxidation of natural metabolites can be a promising strategy to improve their bioactivity. Here, we report the design, synthesis and evaluation of biological properties of αO-SM and βO-SM, novel epoxides of soloxolone methyl (SM), a cyanoenone-bearing derivative of 18βH-glycyrrhetinic acid. We demonstrated that the replacement of a double-bound within the cyanoenone pharmacophore group of SM with α- and β-epoxide moieties did not abrogate the high antitumor and anti-inflammatory potentials of the triterpenoid. It was found that novel SM epoxides induced the death of tumor cells at low micromolar concentrations (IC₅₀^(24h) = 0.7–4.1 µM) via the induction of mitochondrial-mediated apoptosis, reinforced intracellular accumulation of doxorubicin in B16 melanoma cells, probably by direct interaction with key drug efflux pumps (P-glycoprotein, MRP1, MXR1), and the suppressed pro-metastatic phenotype of B16 cells, effectively inhibiting their metastasis in a murine model. Moreover, αO-SM and βO-SM hampered macrophage functionality in vitro (motility, NO production) and significantly suppressed carrageenan-induced peritonitis in vivo. Furthermore, the effect of the stereoisomerism of SM epoxides on the mentioned bioactivities and toxic profiles of these compounds in vivo were evaluated. Considering the comparable antitumor and anti-inflammatory effects of SM epoxides with SM and reference drugs (dacarbazine, dexamethasone), αO-SM and βO-SM can be considered novel promising antitumor and anti-inflammatory drug candidates.

A Mini-Review on Structure-Activity Relationships of Glycyrrhetinic Acid Derivatives with Diverse Bioactivities

Pentacyclic triterpenoids, consisting of six isoprene units, are a kind of natural active substance. At present, numerous pentacyclic triterpene have been observed and classified into four subgroups of oleanane, ursane, lupane, and xylene on the basis of the carbon skeleton. Among them, oleanane is the most popular due to its rich backbone and diverse bioactivities. 18β-Glycyrrhetinic acid (GA), an oleanane-type pentacyclic triterpene isolated from licorice roots, possesses diverse bioactivities including antitumor, anti-inflammatory, antiviral, antimicrobial, enzyme inhibitor, hepatoprotective and so on. It has received more attention in medicinal chemistry due to the advantages of easy-to-access and rich bioactivity. Thus, numerous novel lead compounds were synthesized using GA as a scaffold. Herein, we summarize the structure-activity relationship and synthetic methodologies of GA derivatives from 2010 to 2020 as well as the most active GA derivatives. Finally, we anticipate that this review can benefit future research on structural modifications of GA to enhance bioactivity and provide an example for developing pentacyclic triterpene-based novel drugs.

Antiinflammatory phytochemicals against virus-induced hyperinflammatory responses: Scope, rationale, application, and limitations

Uncontrolled inflammatory responses or cytokine storm associated with viral infections results in deleterious consequences such as vascular leakage, severe hemorrhage, shock, immune paralysis, multi-organ failure, and even death. With the emerging new viral infections and lack of effective prophylactic vaccines, evidence-based complementary strategies that limit viral infection-mediated hyperinflammatory responses could be a promising approach to limit host tissue injury. The present review emphasizes the potentials of antiinflammatory phytochemicals in limiting hyperinflammatory injury caused by viral infections. The predominant phytochemicals along with their mechanism in limiting hyperimmune and pro-inflammatory responses under viral infection have been reviewed comprehensively. How certain phytochemicals can be effective in limiting hyper-inflammatory response indirectly by favorably modulating gut microbiota and maintaining a functional intestinal barrier has also been presented. Finally, we have discussed improved systemic bioavailability of phytochemicals, efficient delivery strategies, and safety measures for effective antiinflammatory phytotherapies, in addition to emphasizing the requirement of tightly controlled clinical studies to establish the antiinflammatory efficacy of the phytochemicals. Collectively, the review provides a scooping overview on the potentials of bioactive phytochemicals to mitigate pro-inflammatory injury associated with viral infections.

Core genes involved in the regulation of acute lung injury and their association with COVID-19 and tumor progression: A bioinformatics and experimental study

Acute lung injury (ALI) is a specific form of lung damage caused by different infectious and non-infectious agents, including SARS-CoV-2, leading to severe respiratory and systemic inflammation. To gain deeper insight into the molecular mechanisms behind ALI and to identify core elements of the regulatory network associated with this pathology, key genes involved in the regulation of the acute lung inflammatory response (Il6, Ccl2, Cat, Serpine1, Eln, Timp1, Ptx3, Socs3) were revealed using comprehensive bioinformatics analysis of whole-genome microarray datasets, functional annotation of differentially expressed genes (DEGs), reconstruction of protein-protein interaction networks and text mining. The bioinformatics data were validated using a murine model of LPS-induced ALI; changes in the gene expression patterns were assessed during ALI progression and prevention by anti-inflammatory therapy with dexamethasone and the semisynthetic triterpenoid soloxolone methyl (SM), two agents with different mechanisms of action. Analysis showed that 7 of 8 revealed ALI-related genes were susceptible to LPS challenge (up-regulation: Il6, Ccl2, Cat, Serpine1, Eln, Timp1, Socs3; down-regulation: Cat) and their expression was reversed by the pre-treatment of mice with both anti-inflammatory agents. Furthermore, ALI-associated nodal genes were analysed with respect to SARS-CoV-2 infection and lung cancers. The overlap with DEGs identified in postmortem lung tissues from COVID-19 patients revealed genes (Saa1, Rsad2, Ifi44, Rtp4, Mmp8) that (a) showed a high degree centrality in the COVID-19-related regulatory network, (b) were up-regulated in murine lungs after LPS administration, and (c) were susceptible to anti-inflammatory therapy. Analysis of ALI-associated key genes using The Cancer Genome Atlas showed their correlation with poor survival in patients with lung neoplasias (Ptx3, Timp1, Serpine1, Plaur). Taken together, a number of key genes playing a core function in the regulation of lung inflammation were found, which can serve both as promising therapeutic targets and molecular markers to control lung ailments, including COVID-19-associated ALI.

Uncovering the anti-angiogenic effect of semisynthetic triterpenoid CDDO-Im on HUVECs by an integrated network pharmacology approach

AIM

To reveal the molecular mechanism of anti-angiogenic activity of semisynthetic triterpenoid CDDO-Im.

MATERIALS AND METHODS

Using re-analysis of cDNA microarray data of CDDO-Im-treated human vascular endothelial cells (HUVECs) (GSE71622), functional annotation of revealed differentially expressed genes (DEGs) and analysis of their co-expression, the key processes induced by CDDO-Im in HUVECs were identified. Venn diagram analysis was further performed to reveal the common DEGs, i.e. genes both susceptible to CDDO-Im and involved in the regulation of angiogenesis. A list of probable protein targets of CDDO-Im was prepared based on Connectivity Map/cheminformatics analysis and chemical proteomics data, among which the proteins that were most associated with the angiogenesis-related regulome were identified. Finally, identified targets were validated by molecular docking and text mining approaches.

KEY FINDINGS

The effect of CDDO-Im in HUVECs can be divided into two main phases: the short early phase (0.5-3 h) with an acute FOXD1/CEBPA/JUNB-regulated pro-angiogenic response induced by xenobiotic stress, and the second anti-angiogenic step (6-24 h) with massive suppression of various angiogenesis-related processes, accompanied by the activation of cytoprotective mechanisms. Our analysis showed that the anti-angiogenic activity of CDDO-Im is mediated by its inhibition of the expression of PLAT, ETS1, A2M, SPAG9, RASGRP3, FBXO32, GCNT1 and HDGFRP3 and its direct interactions with EGFR, mTOR, NOS2, HSP90AA1, MDM2, SYK, IRF3, ATR and KIF14.

SIGNIFICANCE

Our findings provide valuable insights into the understanding of the molecular mechanisms of the anti-angiogenic activity of cyano enone-bearing triterpenoids and revealed a range of novel promising therapeutic targets to control pathological neovascularization.

Glycyrrhetinic acid derivatives as Zika virus inhibitors: Synthesis and antiviral activity in vitro

Zika virus (ZIKV) is an arbovirus of the Flaviviridae family (Flavivirus genus), causing serious neurological complications, such as Guillain-Barre Syndrome (GBS) in adults and fetal microcephaly. Licensed vaccines or specific antiviral agents against ZIKV do not currently exist. Therefore, the search and development of anti-ZIKV agents are particularly relevant and necessary. Glycyrrhetinic (3β-hydroxy-11-oxo-18βH-Olean-12-en-30-oic acid) (GA) 1 is one of the well-known pentacyclic triterpenoids isolated from licorice root (Glycyrrhiza glabra L., Gl. uralensis Fisher) (Leguminosae) possessing many biological features, including antiviral activity. This paper is devoted to the synthesis and studies of a number of nitrogen and sulfur-containing GA derivatives as ZIKV inhibitors. Sixteen GA and related triterpenoids (3β-hydroxy-18βH-Olean-12-en-30-oic acid and 3β-hydroxy-11-oxo-18βH-Olean-12(13),18(19)-dien-30-oic acid) derivatives were synthesized (amides, semi- and thiosemicarbazones, and 1,2,3-thiadiazoles) and antiviral activity against ZIKV was studied in vitro, including the inhibitory assays on cytopathic effect (CPE), viral protein synthesis, and replication stages. Four active compounds were found among GA derivatives tested, 13 (3-O-acetyl-30-aminopyridine GA), 16 (3-semicarbazone-30-butyl GA), 18 (1,2,3-thiadiazole-30-methyl GA), and 19 (1,2,3-thiadiazole-30-butyl GA) with IC₅₀ < 1 μM against ZIKV replication. These compounds had a stronger inhibitory activity on ZIKV-induced CPE and viral protein translation in infected cells as compared to derivatives of 11-desoxo-GA. The most active compound was amide 13 (IC₅₀ 0.13 μM, TI ˃ 384). Time-of-addition assays indicated that 1,2,3-thiadiazole ring is important for inhibiting viral entry stage (compounds 18 and 19), while the 30-butyl ester group influenced on post-entry stage (compound 19). The molecular docking analysis demonstrated that lead compounds 13 and 19 forms a hydrogen-bond interaction with the catalytic triad (His51-Asp75-Ser135) of ZIKV NS2B-NS3 protease. Therefore, the active GA derivatives are promising for developing new antiviral agents against ZIKV infection.

Cyano Enone-Bearing Triterpenoid Soloxolone Methyl Inhibits Epithelial-Mesenchymal Transition of Human Lung Adenocarcinoma Cells In Vitro and Metastasis of Murine Melanoma In Vivo

Introduction of α-cyano α,β-unsaturated carbonyl moiety into natural cyclic compounds markedly improves their bioactivities, including inhibitory potential against tumor growth and metastasis. Previously, we showed that cyano enone-bearing derivatives of 18βH-glycyrrhetinic (GA) and deoxycholic acids displayed marked cytotoxicity in different tumor cell lines. Moreover, GA derivative soloxolone methyl (SM) was found to induce ER stress and apoptosis in tumor cells in vitro and inhibit growth of carcinoma Krebs-2 in vivo. In this work, we studied the effects of these compounds used in non-toxic dosage on the processes associated with metastatic potential of tumor cells. Performed screening revealed SM as a hit compound, which inhibits motility of murine melanoma B16 and human lung adenocarcinoma A549 cells and significantly suppresses colony formation of A549 cells. Further study showed that SM effectively blocked transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition (EMT) of A549 cells: namely, inhibited TGF-β-stimulated motility and invasion of tumor cells as well as loss of their epithelial characteristics, such as, an acquisition of spindle-like phenotype, up- and down-regulation of mesenchymal (vimentin, fibronectin) and epithelial (E-cadherin, zona occludens-1 (ZO-1)) markers, respectively. Network pharmacology analysis with subsequent verification by molecular modeling revealed that matrix metalloproteinases MMP-2/-9 and c-Jun N-terminal protein kinase 1 (JNK1) can be considered as hypothetical primary targets of SM, mediating its marked anti-EMT activity. The inhibitory effect of SM on EMT revealed in vitro was further confirmed in a metastatic model of murine B16 melanoma: SM was found to effectively block metastatic dissemination of melanoma B16 cells in vivo, increase expression of E-cadherin and suppress expression of MMP-9 in lung metastatic foci. Altogether, our data provided valuable information for a better understanding of the antitumor activity of cyano enone-bearing semisynthetic compounds and revealed SM as a promising anti-metastatic drug candidate.

Dual Effect of Soloxolone Methyl on LPS-Induced Inflammation In Vitro and In Vivo

Plant-extracted triterpenoids belong to a class of bioactive compounds with pleotropic functions, including antioxidant, anti-cancer, and anti-inflammatory effects. In this work, we investigated the anti-inflammatory and anti-oxidative activities of a semisynthetic derivative of 18βH-glycyrrhetinic acid (18βH-GA), soloxolone methyl (methyl 2-cyano-3,12-dioxo-18βH-olean-9(11),1(2)-dien-30-oate, or SM) in vitro on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and in vivo in models of acute inflammation: LPS-induced endotoxemia and carrageenan-induced peritonitis. SM used at non-cytotoxic concentrations was found to attenuate the production of reactive oxygen species and nitric oxide (II) and increase the level of reduced glutathione production by LPS-stimulated RAW264.7 cells. Moreover, SM strongly suppressed the phagocytic and migration activity of activated macrophages. These effects were found to be associated with the stimulation of heme oxigenase-1 (HO-1) expression, as well as with the inhibition of nuclear factor-κB (NF-κB) and Akt phosphorylation. Surprisingly, it was found that SM significantly enhanced LPS-induced expression of the pro-inflammatory cytokines interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in RAW264.7 cells via activation of the c-Jun/Toll-like receptor 4 (TLR4) signaling axis. In vivo pre-exposure treatment with SM effectively inhibited the development of carrageenan-induced acute inflammation in the peritoneal cavity, but it did not improve LPS-induced inflammation in the endotoxemia model.

Trioxolone Methyl, a Novel Cyano Enone-Bearing 18βH-Glycyrrhetinic Acid Derivative, Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice

Semi-synthetic triterpenoids, bearing cyano enone functionality in ring A, are considered to be novel promising therapeutic agents with complex inhibitory effects on tissue damage, inflammation and tumor growth. Previously, we showed that the cyano enone-containing 18βH-glycyrrhetinic acid derivative soloxolone methyl (SM) effectively suppressed the inflammatory response of macrophages in vitro and the development of influenza A-induced pneumonia and phlogogen-stimulated paw edema in vivo. In this work, we reported the synthesis of a novel 18βH-glycyrrhetinic acid derivative trioxolone methyl (TM), bearing a 2-cyano-3-oxo-1(2)-en moiety in ring A and a 12,19-dioxo-9(11),13(18)-dien moiety in rings C, D, and E. TM exhibited a high inhibitory effect on nitric oxide (II) production by lipopolysaccharide-stimulated J774 macrophages in vitro and dextran sulfate sodium (DSS)-induced colitis in mice, displaying higher anti-inflammatory activity in comparison with SM. TM effectively suppressed the DSS-induced epithelial damage and inflammatory infiltration of colon tissue, the hyperproduction of colonic neutral mucin and TNFα and increased glutathione synthesis. Our in silico analysis showed that Akt1, STAT3 and dopamine receptor D2 can be considered as mediators of the anti-colitic activity of TM. Our findings provided valuable information for a better understanding of the anti-inflammatory activity of cyano enone-bearing triterpenoids and revealed TM as a promising anti-inflammatory candidate.

Novel 3'-Substituted-1',2',4'-Oxadiazole Derivatives of 18βH-Glycyrrhetinic Acid and Their O-Acylated Amidoximes: Synthesis and Evaluation of Antitumor and Anti-Inflammatory Potential In Vitro and In Vivo

A series of novel 18βH-glycyrrhetinic acid (GA) derivatives containing 3'-(alkyl/phenyl/pyridin(-2″, -3″, and -4″)-yl)-1',2',4'-oxadiazole moieties at the C-30 position were synthesized by condensation of triterpenoid's carboxyl group with corresponding amidoximes and further cyclization. Screening of the cytotoxicity of novel GA derivatives on a panel of tumor cell lines showed that the 3-acetoxy triterpenoid intermediates-O-acylated amidoxime 3a-h-display better solubility under bioassay conditions and more pronounced cytotoxicity compared to their 1',2',4'-oxadiazole analogs 4f-h (median IC50 = 7.0 and 49.7 µM, respectively). Subsequent replacement of the 3-acetoxy group by the hydroxyl group of pyridin(-2″, 3″, and -4″)-yl-1',2',4'-oxadiazole-bearing GA derivatives produced compounds 5f-h, showing the most pronounced selective toxicity toward tumor cells (median selectivity index (SI) > 12.1). Further detailed analysis of the antitumor activity of hit derivative 5f revealed its marked proapoptotic activity and inhibitory effects on clonogenicity and motility of HeLa cervical carcinoma cells in vitro, and the metastatic growth of B16 melanoma in vivo. Additionally, the comprehensive in silico study revealed intermediate 3d, bearing the tert-butyl moiety in O-acylated amidoxime, as a potent anti-inflammatory candidate, which was able to effectively inhibit inflammatory response induced by IFNγ in macrophages in vitro and carrageenan in murine models in vivo, probably by primary interactions with active sites of MMP9, neutrophil elastase, and thrombin. Taken together, our findings provide a basis for a better understanding of the structure-activity relationship of 1',2',4'-oxadiazole-containing triterpenoids and reveal two hit molecules with pronounced antitumor (5f) and anti-inflammatory (3d) activities.

Deep insights into the response of human cervical carcinoma cells to a new cyano enone-bearing triterpenoid soloxolone methyl: a transcriptome analysis

Semisynthetic triterpenoids, bearing cyano enone functionality in ring A, are considered now as novel promising anti-tumor agents. However, despite the large-scale studies, their effects on cervical carcinoma cells and, moreover, mechanisms underlying cell death activation by such compounds in this cell type have not been fully elucidated. In this work, we attempted to reconstitute the key pathways and master regulators involved in the response of human cervical carcinoma KB-3-1 cells to the novel glycyrrhetinic acid derivative soloxolone methyl (SM) by a transcriptomic approach. Functional annotation of differentially expressed genes, analysis of their cis^- regulatory sequences and protein-protein interaction network clearly indicated that stress of endoplasmic reticulum (ER) is the central event triggered by SM in the cells. A range of key ER stress sensors and transcription factor AP-1 were identified as upstream transcriptional regulators, controlling the response of the cells to SM. Additionally, by using Gene Expression Omnibus data, we showed the ability of SM to modulate the expression of key genes involved in regulation of the high proliferative rate of cervical carcinoma cells. Further Connectivity Map analysis revealed similarity of SM's effects with known ER stress inducers thapsigargin and geldanamycin, targeting SERCA and Grp94, respectively. According to the molecular docking study, SM could snugly fit into the active sites of these proteins in the positions very close to that of both inhibitors. Taken together, our findings provide a basis for the better understanding of the intracellular processes in tumor cells switched on in response to cyano enone-bearing triterpenoids.