The estrogenic effect of trigonelline and 3,3-diindolymethane on cell growth in non-malignant colonocytes

Estrogenic actions of alkaloids: Structural characteristics and molecular mechanisms

This comprehensive review of estrogenic alkaloids reveals that although the number is small, they exhibit a wide range of structures, biosynthesis pathways, mechanisms of action, and applications. Estrogenic alkaloids belong to different classes, different biosynthetic pathways, different estrogenic actions (estrogenic/synergistic, anti-estrogenic/antagonistic, biphasic, and acting as a selective estrogen receptor modulator or SERM), different receptor-initiated signaling pathways, different ways of modulations of estrogen action, and different applications. The future applications of estrogenic alkaloids, such as those for diagnostics, drug development, and therapeutics, are considered with the help of new databases containing comprehensive descriptions of their relationships and more elaborate artificial intelligence-based prediction technologies. Structure-activity studies reveal the significance of the nitrogen atom for their structural and functional diversity, which may help support their broader applications. Based on the summary of previous reports, estrogenic alkaloids have significant potential for future applications.

Pharmacological Activities, Therapeutic Effects, and Mechanistic Actions of Trigonelline

Trigonelline (TRG) is a natural polar hydrophilic alkaloid that is found in many plants such as green coffee beans and fenugreek seeds. TRG potentially acts on multiple molecular targets, including nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor γ, glycogen synthase kinase, tyrosinase, nerve growth factor, estrogen receptor, amyloid-β peptide, and several neurotransmitter receptors. In this review, we systematically summarize the pharmacological activities, medicinal properties, and mechanistic actions of TRG as a potential therapeutic agent. Mechanistically, TRG can facilitate the maintenance and restoration of the metabolic homeostasis of glucose and lipids. It can counteract inflammatory constituents at multiple levels by hampering pro-inflammatory factor release, alleviating inflammatory propagation, and attenuating tissue injury. It concurrently modulates oxidative stress by the blockage of the detrimental Nrf2 pathway when autophagy is impaired. Therefore, it exerts diverse therapeutic effects on a variety of pathological conditions associated with chronic metabolic diseases and age-related disorders. It shows multidimensional effects, including neuroprotection from neurodegenerative disorders and diabetic peripheral neuropathy, neuromodulation, mitigation of cardiovascular disorders, skin diseases, diabetic mellitus, liver and kidney injuries, and anti-pathogen and anti-tumor activities. Further validations are required to define its specific targeting molecules, dissect the underlying mechanistic networks, and corroborate its efficacy in clinical trials.

The neuroprotective and antidiabetic effects of trigonelline: A review of signaling pathways and molecular mechanisms

The global epidemic of diabetes has brought heavy pressure on public health. New effective anti-diabetes strategies are urgently needed. Trigonelline is the main component of fenugreek, which has been proved to have a good therapeutic effect on diabetes and diabetic complications. Trigonelline achieves amelioration of diabetes, the mechanisms of which include the modulation of insulin secretion, a reduction in oxidative stress, and the improvement of glucose tolerance and insulin resistance. Besides, trigonelline has been reported to be a neuroprotective agent against many neurologic diseases including Alzheimer's disease, Parkinson's disease, stroke, and depression. Concerning the potential therapeutic effects of trigonelline, comprehensive clinical trials are warranted to evaluate this valuable molecule.

PPARγ activation by pioglitazone enhances the anti-proliferative effects of doxorubicin on pro-monocytic THP-1 leukemia cells via inducing apoptosis and G2/M cell cycle arrest

PURPOSE

Doxorubicin (DOX) is a common chemotherapeutic agent, with toxic side effects, and chemoresistance. Combination chemotherapy is a successful approach to overcome these limitations. Here, we investigated the effects of pioglitazone (PGZ), a PPARγ agonist, and/or DOX on the viability, cell cycle, apoptosis on THP-1 cells and normal human monocytes (NHMs).

METHODS

MTT assay was used to evaluate the cytotoxicity of DOX and/or PGZ. Cell cycle progression and apoptosis induction were examined by PI or Annexin V-PI double staining, and analyzed by flow cytometry. Quantitative RT-PCR was used to evaluate the changes in the mRNA expression of cell cycle progression or apoptosis-associated genes including P27, P21, CDK2, P53, BCL2 and FasR.

RESULTS

DOX, PGZ and DOX + PGZ exerted their cytotoxic effects in a dose- and time-dependent manner with low toxicity on NHMs. The cell growth inhibitory effects of DOX were in association with G2/M arrest, while PGZ executed S phase arrest. PGZ treatment enhanced G2/M among DOX-treated combinations with moderate elevation in the S phase. DOX, PGZ and combined treatments induced apoptosis (mostly late phase) in a dose-dependent manner. All treatments resulted in the significant overexpression of p21, p27, p53 and FasR genes and downregulation of CDK2. DOX + PGZ combined treatments exhibited the most significant changes in mRNA expression.

CONCLUSION

We demonstrated that the antiproliferative, cell cycle regulation and apoptosis-inducing capacity of DOX was enhanced by PGZ in THP-1 leukemia cells in a dose-dependent manner. Therefore, the combination of DOX + PGZ could be used as a novel combination to target AML.

Studies on the mode of action of synthetic diindolylmethane derivatives against triple negative breast cancer cells

Diindolylmethane (DIM) is a metabolic product of indole-3-carbinol (I3C), the major phytochemicals present in cruciferous vegetables, which can modulate multiple signalling pathways in cancer. The present study deals with the mechanism of action of two synthetic biaryl conjugates of DIM in triple negative breast cancer cells. Out of twelve DIM derivatives tested, two compounds, DIM-1 and DIM-4, exhibit cytotoxicity with GI₅₀ values of 9.83±0.2195 μM and 8.726±0.5234 μM, respectively, in 2D culture. In 3D culture, DIM-1 and DIM-4 show GI₅₀ values of 24.000±0.7240 μM and 19.230±0.3754 μM, respectively. The non-toxic nature of the compounds was also established by the toxicity studies using the zebrafish model system. The two compounds induced apoptosis and anoikis in the cancer cells, which was confirmed by morphological analysis, nuclear fragmentation, membrane integrity assay, caspase activity measurements, and modulation of pro/anti-apoptotic proteins. The compounds inhibited cell migration and MMP-2 and MMP-9 activities indicating their anti-metastatic property. They also reduced the expression of active Ras, phosphorylated forms of PI3K, Akt and mTOR. Immunofluorescence studies revealed the reduced expression of EGFR and pEGFR in treated cells. To conclude, DIM-1 and DIM-4 induced anti-breast cancer effects by blocking EGF receptor and subsequently inhibiting Ras-mediated PI3K-Akt-mTOR signalling pathway.

Trigonelline prevents kidney stone formation processes by inhibiting calcium oxalate crystallization, growth and crystal-cell adhesion, and downregulating crystal receptors

Trigonelline is the second most abundant bioactive alkaloid found in coffee. It is classified as a phytoestrogen with similar structure as of estradiol and exhibits an estrogenic effect. A previous study has reported that fenugreek seed extract rich with trigonelline can reduce renal crystal deposition in ethylene glycol-induced nephrolithiatic rats. However, direct evidence of such anti-lithogenic effects of trigonelline and underlying mechanisms have not previously been reported. Our study therefore addressed the protective effects and mechanisms of trigonelline against kidney stone-forming processes using crystallization, crystal growth, aggregation and crystal-cell adhesion assays. Also, proteomics was applied to identify changes in receptors for calcium oxalate monohydrate (COM), the most common stone-forming crystal, on apical membranes of trigonelline-treated renal tubular cells. The analyses revealed that trigonelline significantly reduced COM crystal size, number and mass during crystallization. Additionally, trigonelline dose-dependently inhibited crystal growth and crystal-cell adhesion, but did not affect crystal aggregation. Mass spectrometric protein identification showed the smaller number of COM crystal receptors on apical membranes of the trigonelline-treated cells. Western blotting confirmed the decreased levels of some of these crystal receptors by trigonelline. These data highlight the protective mechanisms of trigonelline against kidney stone development by inhibiting COM crystallization, crystal growth and crystal-cell adhesion via downregulation of the crystal receptors on apical membranes of renal tubular cells.

Estrogen receptor actions in colitis

In recent years, researchers have demonstrated that estrogen and its receptors, aside from their role in regulating several biological functions, contribute to the development and progression/severity of inflammatory bowel diseases (IBDs). IBDs include both ulcerative colitis (UC) and Crohn's disease (CD). Epidemiological data indicate a clear difference in the incidence, severity, and complications of IBDs between sexes. Men present a higher risk of developing colitis than women and a higher risk of developing colorectal cancer, a common complication of this condition. However, fluctuations of estrogen levels have yielded inconsistent data, where oral contraceptives and hormone replacement therapy have been associated with an increased risk of IBDs in premenopausal women but significantly reduce disease activity after menopause. Likewise, improvement of symptoms related to CD has been reported during pregnancy, but not in UC, who often experience worsening symptoms. In the colonic epithelium, estrogen receptor β (ERβ) is the predominant form of the protein expressed, and it helps maintain normal epithelial function and organization. Preclinical data suggest that ER expression and activation via estrogen confers different responses on disease severity depending on the model used to induce colitis, which may reflect what is observed in patients with IBDs. Hence, this review aims to provide an overview of estrogen and its receptors, particularly ERβ, in the pathophysiology of IBDs.

DIM-C-pPhtBu induces lysosomal dysfunction and unfolded protein response - mediated cell death via excessive mitophagy

Despite technological advances in cancer treatment, the survival rate of patients with head and neck cancer (HNC) has not improved significantly. Many studies have shown that endoplasmic reticulum (ER) stress-related signals are associated with mitochondrial damage and that these signals determine whether cells maintain homeostasis or activate cell death programs. The unfolded protein response (UPR) is regulated by ER membrane proteins such as double-stranded RNA-activated protein kinase R(PKR)-like ER kinase (PERK), which directly activate transcription of chaperones or genes that function in redox homeostasis, protein secretion, or cell death programs. In this study, we focused on the role of mitophagy and ER stress-mediated cell death induced by DIM-C-pPhtBu in HNC cancer. We found that DIM-C-pPhtBu, a compound that activates ER stress in many cancers, induced lysosomal dysfunction, excessive mitophagy, and cell death in HNC cells. Moreover, DIM-C-pPhtBu strongly inhibited HNC progression in a xenograft model by altering mitophagy related protein expression. Taken together, the results demonstrate that DIM-C-pPhtBu induces excessive mitophagy and eventually UPR-mediated cell death in HNC cells, suggesting that new anti-cancer drugs could be developed based on the connection between mitophagy and cancer cell death.

Absorption, Pharmacokinetics, and Urinary Excretion of Pyridines After Consumption of Coffee and Cocoa-Based Products Containing Coffee in a Repeated Dose, Crossover Human Intervention Study

SCOPE

The present study assesses the absorption, pharmacokinetics, and urinary excretion of coffee pyridines and their metabolites after daily regular exposure to specific dosages of coffee or cocoa-based products containing coffee (CBPCC), considering different patterns of consumption.

METHODS AND RESULTS

In a three-arm, crossover, randomized trial, 21 volunteers are requested to randomly consume for 1 month: one cup of espresso coffee per day, three cups of espresso coffee per day, or one cup of espresso coffee plus two CBPCC twice per day. The last day of the one-month treatment, blood and urine samples are collected for 24 h. Trigonelline, N-methylpyridinium, N-methylnicotinamide, and N-methyl-4-pyridone-5-carboxamide are quantified. Trigonelline and N-methylpyridinium absorption curves and 24-h urinary excretion reflect the daily consumption of different servings of coffee or CBPCC, showing also significant differences in main pharmacokinetic parameters. Moreover, inter-subject variability due to sex and smoking is assessed, showing sex-related differences in the metabolism of trigonelline and smoking-related ones for N-methylpyridinium.

CONCLUSION

The daily exposure to coffee pyridines after consumption of different coffee dosages in a real-life setting is established. This data will be useful for future studies aiming at evaluating the bioactivity of coffee-derived circulating metabolites in cell experiments, mimicking more realistic experimental conditions.

Trigonelline-loaded chitosan nanoparticles prompted antitumor activity on glioma cells and biocompatibility with pheochromocytoma cells

Trigonelline-loaded water-soluble chitosan nanoparticles (Trigo-WSCS NPs) were prepared for the treatment of glioblastoma (targeting C6 glioma cells) and also evaluated its biocompatibility with rat adrenal pheochromocytoma cells (PC12 cells). WSCS-Trigo NPs characteristics were determined using UV-Visible spectrophotometer, FTIR, XRD, TEM, DLS, and Zeta potential. Trigo-WSCS NPs were noted to have a spherical shape, with an average size of 356 nm. Trigo-WSCS NPs zeta potential was 30.9 mv, which expresses its good stability. The WSCS-Trigo NPs considerably inhibited the growth of rat C6 glioma cells and exhibited an IC₅₀ concentration of 34 μg/mL. Further, Trigo-WSCS NPs were biocompatible with PC12 cells in terms of enhancing neurite growth and differentiation. In conclusion, Trigo-WSCS NPs could act as an antitumor drug for the treatment of glioblastoma as suggested by the in vitro studies.

Estrogenic Activity of Coffee Constituents

Here, the constituents of coffee with estrogenic activity are summarized by a comprehensive literature search, and their mechanisms of action for their physiological effects are discussed at the molecular and cellular levels. The estrogenic activity of coffee constituents, such as acids, caramelized products, carbohydrates, lignin, minerals, nitrogenous compounds, oil (lipids), and others, such as volatile compounds, was first evaluated by activity assays, such as animal tests, cell assay, ligand-binding assay, protein assay, reporter-gene assay, transcription assay, and yeast two-hybrid assay. Second, the health benefits associated with the estrogenic coffee constituents, such as bone protection, cancer treatment/prevention, cardioprotection, neuroprotection, and the improvement of menopausal syndromes, were summarized, including their potential therapeutic/clinical applications. Inconsistent results regarding mixed estrogenic/anti-estrogenic/non-estrogenic or biphasic activity, and unbeneficial effects associated with the constituents, such as endocrine disruption, increase the complexity of the effects of estrogenic coffee constituents. However, as the increase of the knowledge about estrogenic cell signaling, such as the types of specific signaling pathways, selective modulations of cell signaling, signal crosstalk, and intercellular/intracellular networks, pathway-based assessment will become a more realistic means in the future to more reliably evaluate the beneficial applications of estrogenic coffee constituents.

Indole-3-carbinol induces G1 cell cycle arrest and apoptosis through aryl hydrocarbon receptor in THP-1 monocytic cell line

OBJECTIVES

The role of aryl hydrocarbon receptor (AhR) in carcinogenesis has been studied recently. Indole-3-carbinol (I3C) is an AhR agonist and a potential anticancer agent. Here, we investigated the effects of I3C on cell cycle progression and apoptosis through activation of AhR on THP-1 acute myeloid leukemia (AML) cell line.

METHODS

MTT viability assay was used to measure the cytotoxic effects of I3C on THP-1 cells. Apoptosis and cell cycle assays were investigated using flow cytometry. Real time RT-PCR was conducted to measure the alterations in the expression of AhR gene, key genes associated with AhR activation (IL1β and CYP1A1) and major genes involved in cell cycle regulation and apoptosis including P27, P21, CDK2, P53, BCL2 and FasR.

RESULTS

Our findings revealed that I3C inhibits the proliferation of THP-1 cells in a dose- and time-dependent manner with minimal toxicity over normal monocytes. The AhR target genes (CYP1A1, IL1β) were overexpressed upon I3C treatment (p < .05 to p < .001). The antiproliferative effects of I3C were in association with programed cell death. I3C downregulated BCL2 and upregulated FasR in THP-1 cells (p < .05 to p < .001). G1 cell cycle arrest was also observed using flow cytometry. G1-acting cell cycle genes (P21, P27 and P53) were overexpressed (p < .05 to p < .001), while CDK2 was downregulated upon I3C treatment (p < .01 to p < .001).

CONCLUSIONS

I3C could exert its antileukemic effects through AhR activation which is associated with programed cell death and G1 cell cycle arrest in a dose- and time-dependent manner. Therefore, AhR could be targeted as a novel treatment possibility in AML.