Artonin E and Structural Analogs from Artocarpus Species Abrogates Estrogen Receptor Signaling in Breast Cancer

In Silico Drug Design of Anti-Breast Cancer Agents

Cancer is a condition marked by abnormal cell proliferation that has the potential to invade or indicate other health issues. Human beings are affected by more than 100 different types of cancer. Some cancer promotes rapid cell proliferation, whereas others cause cells to divide and develop more slowly. Some cancers, such as leukemia, produce visible tumors, while others, such as breast cancer, do not. In this work, in silico investigations were carried out to investigate the binding mechanisms of four major analogs, which are marine sesquiterpene, sesquiterpene lactone, heteroaromatic chalcones, and benzothiophene against the target estrogen receptor-α for targeting breast cancer using Schrödinger suite 2021-4. The Glide module handled the molecular docking experiments, the QikProp module handled the ADMET screening, and the Prime MM-GB/SA module determined the binding energy of the ligands. The benzothiophene analog BT_ER_15f (G-score -15.922 Kcal/mol) showed the best binding activity against the target protein estrogen receptor-α when compared with the standard drug tamoxifen which has a docking score of -13.560 Kcal/mol. TRP383 (tryptophan) has the highest interaction time with the ligand, and hence it could act for a long time. Based on in silico investigations, the benzothiophene analog BT_ER_15f significantly binds with the active site of the target protein estrogen receptor-α. Similar to the outcomes of molecular docking, the target and ligand complex interaction motif established a high affinity of lead candidates in a dynamic system. This study shows that estrogen receptor-α targets inhibitors with better potential and low toxicity when compared to the existing market drugs, which can be made from a benzothiophene derivative. It may result in considerable activity and be applied to more research on breast cancer.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Visible Light-Promoted Green and Sustainable Approach for One-Pot Synthesis of 4,4'-(Arylmethylene)bis(1H-pyrazol-5-ols), In Vitro Anticancer Activity, and Molecular Docking with Covid-19 Mpro

A visible light-promoted, efficient, green, and sustainable strategy has been adopted to unlatch a new pathway toward the synthesis of a library of medicinally important 4,4'-(arylmethylene)bis(1H-pyrazol-5-ols) moieties using substituted aromatic aldehydes and sterically hindered 3-methyl-1-phenyl-2-pyrazoline-5-one in excellent yield. This reaction shows high functional group tolerance and provides a cost-effective and catalyst-free protocol for the quick synthesis of biologically active compounds from readily available substrates. Synthesized compounds were characterized by spectroscopic techniques such as IR, 1HNMR, 13CNMR, and single-crystal XRD analysis. All the synthesized compounds were evaluated for their antiproliferative activities against a panel of five different human cancer cell lines and compared with Tamoxifen using MTT assay. Compound 3m exhibited maximum antiproliferative activity and was found to be more active as compared to Tamoxifen against both the MCF-7 and MDA-MB-231 cell lines with an IC50 of 5.45 and 9.47 μM, respectively. A molecular docking study with respect to COVID-19 main protease (Mpro) (PDB ID: 6LU7) has also been carried out which shows comparatively high binding affinity of compounds 3f and 3g (-8.3 and -8.8 Kcal/mole, respectively) than few reported drugs such as ritonavir, remdesivir, ribacvirin, favipiravir, hydroxychloroquine, chloroquine, and olsaltamivir. Hence, it reveals the possibility of these compounds to be used as effective COVID-19 inhibitors.

Hydroxysafflor Yellow A Alleviates Ischemic Stroke in Rats via HIF-1[Formula: see text], BNIP3, and Notch1-Mediated Inhibition of Autophagy

Stroke has become a major cause of death and disability worldwide. The cellular recycling pathway autophagy has been implicated in ischemia-induced neuronal changes, but whether autophagy plays a beneficial or detrimental role is controversial. Hydroxysafflor Yellow A (HSYA), a popular herbal medicine, is an extract of Carthamus tinctorius and is used to treat ischemic stroke (IS) in China. HSYA has been shown to prevent cardiovascular and cerebral ischemia/reperfusion injury in animal models. However, the specific active ingredients and molecular mechanisms of HSYA in IS remain unclear. Here, we investigated the effect of HSYA treatment on autophagy in a rat model of IS. IS was induced in rats by middle cerebral artery occlusion. Rats were treated once daily for 3 days with saline, HYSA, or the neuroprotective agent Edaravone. Neurobehavioral testing was performed on days 1, 2, and 3 post-surgery. Brains were removed on day 3 post-surgery for histological evaluation of infarct area, morphology, and for qRT-PCR and western blot analysis of the expression of the autophagy factor LC3 and the signaling molecules HIF-1[Formula: see text], BNIP3, and Notch1. Molecular docking studies were performed in silico to predict potential interactions between HSYA and LC3, HIF-1[Formula: see text], BNIP3, and Notch1 proteins. The result showed that HSYA treatment markedly alleviated IS-induced neurobehavioral deficits and reduced brain infarct area and tissue damage. HSYA also significantly reduced hippocampal expression levels of LC3, HIF-1[Formula: see text], BNIP3, and Notch1. The beneficial effect of HSYA was generally superior to that of Edaravone. Molecular modeling suggested that HSYA may bind strongly to HIF-1[Formula: see text], BNIP3, and Notch1 but weakly to LC3. In conclusion, HSYA inhibits post-IS autophagy induction in the brain, possibly by suppressing HIF-1[Formula: see text], BNIP3 and Notch1. HSYA may have utility as a post-IS neuroprotective agent.

Antiproliferative Activity of Triterpenoid and Steroid Compounds from Ethyl Acetate Extract of Calotropis gigantea Root Bark against P388 Murine Leukemia Cell Lines

Calotropis gigantea has been known to produce bioactive secondary metabolites with antiproliferative activities against cancer cells. Herein, we extracted the secondary metabolites using ethyl acetate from its root bark and further tested its antiproliferative activities against P388 murine leukemia cell lines. The subfractions from the ethyl acetate extract was obtained from Vacuum Liquid Column Chromatography (VLCC), and followed by Gravity Column Chromatography (GCC). The subfraction C2 and D1 were identified to contain triterpenoids and steroids with the most potent cytotoxicity against Brine Shrimp Lethality Test (BSLT). A 3-(4,5-dimethylthiazol-2-yl) -2-5 diphenyl tetrazolium bromide (MTT) assay suggested that ethyl acetate extract has the highest antiproliferative activities against P388 murine leukemia cell lines (IC50 = 21.79 μg/mL), as opposed to subfraction C2 (IC50 = 50.64 µg/mL) and subfraction D1 (IC50 = 49.33 µg/mL). The compound identified in subfraction C2 and D1 are taraxerol acetate and calotropone, respectively. Though taraxerol acetate and calotropone were active in inhibiting the leukemic cell lines, their IC50s were lower than the ethyl acetate extract, which is probably due to the synergism of the secondary metabolites.

Artonin E sensitizes TRAIL-induced apoptosis by DR5 upregulation and cFLIP downregulation in TRAIL-refractory colorectal cancer LoVo cells

Background

The TRAIL treatment is an ideal strategy for colorectal cancer (CRC) therapy because of minimal collateral damage to normal cells. Unfortunately, some CRC is TRAIL-refractory cancer, such as LoVo cells. In an effort to overcome TRAIL-refractory cancer, we investigated the effect of artonin E in regulating death receptor 5 (DR5) and cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (cFLIP), two major mediators regulate TRAIL-induced apoptosis, in LoVo cells as a model of TRAIL refractory CRC.

Methods

TRAIL-refractory cancer (LoVo cells) was treated with artonin E and TRAIL. Cell viability was determined by MTT assay. Apoptotic chromatin condensation was observed by fluorescent Hoechst33342 staining. The mRNA and protein expression of DR5 and FLIP was determined by quantitative PCR and Western blotting analysis, respectively.

Results

The combination treatment of artonin E and TRAIL enhanced cytotoxicity and apoptotic chromatin condensation in LoVo cells significantly, while treatment of artonin E or TRAIL alone was not. Artonin E enhanced both mRNA and protein expression of DR5. Interestingly, this is the first report showing that artonin E decreased protein expression of cFLIP. All together we showed that artonin E enhanced TRAIL-induced apoptosis in LoVo cells through DR5 upregulation and cFLIP downregulation.

Conclusions

Artonin E was able to increase DR5 expression and decrease cFLIP expression in LoVo cells. These results showed that LoVo cells sensitized TRAIL-induced apoptosis in combined treatment with artonin E and TRAIL. Therefore, the combination treatment of artonin E and TRAIL is one of the potential strategies used for TRAIL-refractory CRC therapy in the future.

A New Class of Pure Estrogen Alpha Receptor Antagonists; Design, Synthesis and in-vitro Screening

Background:

In view of the estrogenic receptor inhibitory properties of coumarin nucleus, long chain nature of fatty acid and anti-breast cancer activity of fatty acids, it was proposed to attach long chain fatty acids at 3rd,4th and 7th position of coumarin nucleus and evaluate for their anti-breast cancer activity through suitable in-vitro methods.

Methods:

The present study focuses a library of fatty acid coumarin conjugates as ligands to the ligand-binding domain of the human estrogen receptor α (PDB ID 2IOG) and their binding affinities using GLIDE module of Schrodinger after ascertaining their drug-likeness with QIKPROP. The compounds LNAC 8, SAC 1 and OAC 5 are the best hits based on their docking scores as well as the Prime MM-GBSA free energy of binding. Based on the in-silico results and synthetic feasibility the compounds SAC 1 PAC 1 and OAC 1 are synthesized, characterized and investigated for their time interval growth inhibitory effect on MCF-7 which is an ER positive breast cancer cell lines.

Results:

SAC 1, showed better in vitro growth inhibitory effect in sub micromolar range as compared to Tamoxifen, a standard estrogen receptor modulator.

Conclusion:

Conclusively, in silico molecular docking studies have been very useful in predicting the pharmacokinetic profiles and the binding affinities of new hits before a detailed preclinical and clinical evaluation.

The molecular mechanism of the anticancer effect of Artonin E in MDA-MB 231 triple negative breast cancer cells

Nature has provided us with a wide spectrum of disease healing phytochemicals like Artonin E, obtained from the root bark of Artocarpus elasticus. This molecule had been predicted to be drug-like, possessing unique medicinal properties. Despite strides made in chemotherapy, prognosis of the heterogenous aggressive triple negative breast cancer is still poor. This study was conducted to investigate the mechanism of inhibition of Artonin E, a prenylated flavonoid on MDA-MB 231 triple negative breast cancer cell, with a view of mitigating the hallmarks displayed by these tumors. The anti-proliferative effect, mode of cell death and the mechanism of apoptosis induction were investigated. Artonin E, was seen to effectively relinquish MDA-MB 231 breast cancer cells of their apoptosis evading capacity, causing a half-maximal growth inhibition at low concentrations (14.3, 13.9 and 9.8 μM) after the tested time points (24, 48 and 72 hours), respectively. The mode of cell death was observed to be apoptosis with defined characteristics. Artonin E was seen to induce the activation of both extrinsic and intrinsic caspases initiators of apoptosis. It also enhanced the release of total reactive oxygen species which polarized the mitochondrial membrane, compounding the release of cytochrome c. Gene expression studies revealed the upregulation of TNF-related apoptosis inducing ligand and proapoptotic genes with down regulation of anti-apoptotic genes and proteins. A G2/M cell cycle arrest was also observed and was attributed to the observed upregulation of p21 independent of the p53 status. Interestingly, livin, a new member of the inhibitors of apoptosis was confirmed to be significantly repressed. In all, Artonin E showed the potential as a promising candidate to combat the aggressive triple negative breast cancer.

Artonin E induces p53-independent G1 cell cycle arrest and apoptosis through ROS-mediated mitochondrial pathway and livin suppression in MCF-7 cells

Artonin E is a prenylated flavonoid compound isolated from the stem bark of Artocarpus elasticus. This phytochemical has been previously reported to be drug-like with full compliance to Lipinski's rule of five and good physicochemical properties when compared with 95% of orally available drugs. It has also been shown to possess unique medicinal properties that can be utilized in view of alleviating most human disease conditions. In this study, we investigated the cytotoxic mechanism of Artonin E in MCF-7 breast cancer cells, which has so far not been reported. In this context, Artonin E significantly suppressed the breast cancer cell's viability while inducing apoptosis in a dose-dependent manner. This apoptosis induction was caspase dependent, and it is mediated mainly through the intrinsic pathway with the elevation of total reactive oxygen species. Gene and protein expression studies revealed significant upregulation of cytochrome c, Bax, caspases 7 and 9, and p21 in Artonin E-treated MCF-7 cells, while MAPK and cyclin D were downregulated. Livin, a member of the inhibitors of apoptosis, whose upregulation has been noted to precede chemotherapeutic resistance and apoptosis evasion was remarkably repressed. In all, Artonin E stood high as a potential agent in the treatment of breast cancer.