Oleic acid and oleoylethanolamide decrease interferon-γ-induced expression of PD-L1 and induce apoptosis in human lung carcinoma cells

Harnessing the capacity of phytochemicals to enhance immune checkpoint inhibitor therapy of cancers: A focus on brain malignancies

Brain cancers, particularly glioblastoma multiforme (GBM), are challenging health issues with frequent unmet aspects. Today, discovering safe and effective therapeutic modalities for brain tumors is among the top research interests. Immunotherapy is an emerging area of investigation in cancer treatment. Since immune checkpoints play fundamental roles in repressing anti-cancer immunity, diverse immune checkpoint inhibitors (ICIs) have been developed, and some monoclonal antibodies have been approved clinically for particular cancers; nevertheless, there are significant concerns regarding their efficacy and safety in brain tumors. Among the various tools to modify the immune checkpoints, phytochemicals show good effectiveness and excellent safety, making them suitable candidates for developing better ICIs. Phytochemicals regulate multiple immunological checkpoint-related signaling pathways in cancer biology; however, their efficacy for clinical cancer immunotherapy remains to be established. Here, we discussed the involvement of immune checkpoints in cancer pathology and summarized recent advancements in applying phytochemicals in modulating immune checkpoints in brain tumors to highlight the state-of-the-art and give constructive prospects for future research.

DPP3 promotes breast cancer tumorigenesis by stabilizing FASN and promoting lipid synthesis

DPP3, a dipeptidyl peptidase, participates in a variety of pathophysiological processes. DPP3 is upregulated in cancer and might serve as a key factor in the tumorigenesis and progression of various malignancies. However, its specific role and molecular mechanism are still unknown. In this study, the expression of DPP3 in breast cancer tissues is analyzed using TCGA database. Kaplan-Meier survival analysis is performed to estimate the effect of DPP3 on the survival outcomes. To explore the biological function and mechanisms of DPP3 in breast cancer, biochemical and cell biology assays are conducted in vitro. DPP3 expresses at a higher level in breast cancer tissues than that in adjacent tissues in both TCGA database and clinical samples. Patients with high expression of DPP3 have poor survival outcomes. The proliferation and migration abilities of tumor cells with stable DPP3 knockout in breast cancer cell lines are significantly inhibited, and apoptosis is increased in vitro. GSEA analysis shows that DPP3 can affect lipid metabolism and fatty acid synthesis in tumors. Subsequent experiments show that DPP3 could stabilize FASN expression and thus promote fatty acid synthesis in tumor cells. The results of the metabolomic analysis also confirm that DPP3 can affect the content of free fatty acids. This study demonstrates that DPP3 plays a role in the reprogramming of fatty acid metabolism in tumors and is associated with poor prognosis in breast cancer patients. These findings will provide a new therapeutic target for the treatment of breast cancer.

Cymbopogon proximus phytochemicals induce S-phase arrest in A549 lung cancer cell lines via CDK2/cyclin A2 inhibition: gas chromatography-mass spectrometry and molecular docking analyses

Cymbopogon proximus comprises several phytoconstituent classes that are reported to possess anticancer activity; however, studies on the anticancer potentials of the plant are lacking. C. proximus was extracted using solvents with increasing polarity. In-vitro cytotoxic activity of C. proximus extracts was examined against liver (HepG2), lung (A549), prostate (PC3), and bone (MG63) cell lines using MTT assay in comparison to doxorubicin. Flow cytometry was used to analyze the cell cycle for identification of the phase of inhibition. Chemical composition of the most active fraction was examined using the GC/MS technique. Molecular docking was used to explore the mechanism of cytotoxicity against A549, and the results were confirmed by Western blot analysis. Petroleum ether fraction was the highly effective fraction against A549 with IC50 = 14.02 ± 2.79. GC/MS analysis of Pet.Eth led to the identification of nine compounds in unsaponifiable matter and 27 components in the saponifiable fraction. Di-N-octyl phthalate, 3-β-hydroxylean-11.13(18)-dien-30-oic acid methyl ester, elemol hydrocarbons, linoelaidic acid and linoleic acid demonstrated the lowest docking binding scores and similar binding modes against CDK2 as compared to that attained by the native ligand R-Roscovitine "CDK2 ATP inhibitor". Western blot analysis demonstrated that CDK2/cyclinA2 protein expression has been suppressed in A549 cell lines by Pet.Eth fraction.

Oleoylethanolamide and Palmitoylethanolamide Enhance IFNβ-Induced Apoptosis in Human Neuroblastoma SH-SY5Y Cells

Oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) are endogenous lipids that act as agonists of the peroxisome proliferator-activated receptor α (PPARα). Recently, an interest in the role of these lipids in malignant tumors has emerged. Nevertheless, the effects of OEA and PEA on human neuroblastoma cells are still not documented. Type I interferons (IFNs) are immunomodulatory cytokines endowed with antiviral and anti-proliferative actions and are used in the treatment of various pathologies such as different cancer forms (i.e., non-Hodgkin's lymphoma, melanoma, leukemia), hepatitis B, hepatitis C, multiple sclerosis, and many others. In this study, we investigated the effect of OEA and PEA on human neuroblastoma SH-SY5Y cells treated with IFNβ. We focused on evaluating cell viability, cell proliferation, and cell signaling. Co-exposure to either OEA or PEA along with IFNβ leads to increased apoptotic cell death marked by the cleavage of caspase 3 and poly-(ADP ribose) polymerase (PARP) alongside a decrease in survivin and IKBα levels. Moreover, we found that OEA and PEA did not affect IFNβ signaling through the JAK-STAT pathway and the STAT1-inducible protein kinase R (PKR). OEA and PEA also increased the phosphorylation of p38 MAP kinase and programmed death-ligand 1 (PD-L1) expression both in full cell lysate and surface membranes. Furthermore, GW6471, a PPARα inhibitor, and the genetic silencing of the receptor were shown to lower PD-L1 and cleaved PARP levels. These results reveal the presence of a novel mechanism, independent of the IFNβ-prompted pathway, by which OEA and PEA can directly impair cell survival, proliferation, and clonogenicity through modulating and potentiating the intrinsic apoptotic pathway in human SH-SY5Y cells.

From immune checkpoints to therapies: understanding immune checkpoint regulation and the influence of natural products and traditional medicine on immune checkpoint and immunotherapy in lung cancer

Lung cancer is a disease of global concern, and immunotherapy has brought lung cancer therapy to a new era. Besides promising effects in the clinical use of immune checkpoint inhibitors, immune-related adverse events (irAEs) and low response rates are problems unsolved. Natural products and traditional medicine with an immune-modulating nature have the property to influence immune checkpoint expression and can improve immunotherapy's effect with relatively low toxicity. This review summarizes currently approved immunotherapy and the current mechanisms known to regulate immune checkpoint expression in lung cancer. It lists natural products and traditional medicine capable of influencing immune checkpoints or synergizing with immunotherapy in lung cancer, exploring both their effects and underlying mechanisms. Future research on immune checkpoint modulation and immunotherapy combination applying natural products and traditional medicine will be based on a deeper understanding of their mechanisms regulating immune checkpoints. Continued exploration of natural products and traditional medicine holds the potential to enhance the efficacy and reduce the adverse reactions of immunotherapy.

Oleic Acid Exhibits Anti-Proliferative and Anti-Invasive Activities via the PTEN/AKT/mTOR Pathway in Endometrial Cancer

Reprogramming of fatty acid metabolism promotes cell growth and metastasis through a variety of processes that stimulate signaling molecules, energy storage, and membrane biosynthesis in endometrial cancer. Oleic acid is one of the most important monounsaturated fatty acids in the human body, which appears to have both pro- and anti-tumorigenic activities in various pre-clinical models. In this study, we evaluated the potential anti-tumor effects of oleic acid in endometrial cancer cells and the LKB1fl/flp53fl/fl mouse model of endometrial cancer. Oleic acid increased lipogenesis, inhibited cell proliferation, caused cell cycle G1 arrest, induced cellular stress and apoptosis, and suppressed invasion in endometrial cancer cells. Targeting of diacylglycerol acyltransferases 1 and 2 effectively increased the cytotoxicity of oleic acid. Moreover, oleic acid significantly increased the expression of wild-type PTEN, and knockdown of PTEN by shRNA partially reversed the anti-proliferative and anti-invasive effects of oleic acid. Inhibition of the AKT/mTOR pathway by ipatasertib effectively increased the anti-tumor activity of oleic acid in endometrial cancer cells. Oleic acid treatment (10 mg/kg, daily, oral) for four weeks significantly inhibited tumor growth by 52.1% in the LKB1fl/flp53fl/fl mice. Our findings demonstrated that oleic acid exhibited anti-tumorigenic activities, dependent on the PTEN/AKT/mTOR signaling pathway, in endometrial cancer.

In vitro evaluation of the anti‑breast cancer properties and gene expression profiles of Thai traditional formulary medicine extracts

Breast cancer is a leading cause of cancer-related deaths worldwide. Moreover, standard treatments are limited, so new alternative treatments are required. Thai traditional formulary medicine (TTFM) utilizes certain herbs to treat different diseases due to their dominant properties including anti-fungal, anti-bacterial, antigenotoxic, anti-inflammatory and anti-cancer actions. However, very little is known about the anti-cancer properties of TTFM against breast cancer cells and the underlying molecular mechanism has not been elucidated. Therefore, the present study, evaluated the metabolite profiles of TTFM extracts, the anti-cancer activities of TTFM extracts, their effects on the apoptosis pathway and associated gene expression profiles. Liquid chromatography with tandem mass spectroscopy analysis identified a total of 226 compounds within the TTFM extracts. Several of these compounds have been previously shown to have an anti-cancer effect in certain cancer types. The MTT results demonstrated that the TTFM extracts significantly reduced the cell viability of the breast cancer 4T1 and MDA-MB-231 cell lines. Moreover, an apoptosis assay, demonstrated that the TTFM extracts significantly increased the proportion of apoptotic cells. Furthermore, the RNA-sequencing results demonstrated that 25 known genes were affected by TTFM treatment in 4T1 cells. TTFM treatment significantly up-regulated Slc5a8 and Arhgap9 expression compared with untreated cells. Moreover, Cybb, and Bach2os were significantly downregulated after TTFM treatment compared with untreated cells. Reverse transcription-quantitative PCR demonstrated that TTFM extract treatment significantly increased Slc5a8 and Arhgap9 mRNA expression levels and significantly decreased Cybb mRNA expression levels. Moreover, the mRNA expression levels of Bax and Casp9 were significantly increased after TTFM treatment in 4T1 cells compared with EpH4-Ev cells. These findings indicated anti-breast cancer activity via induction of the apoptotic process. However, further experiments are required to elucidate how TTFM specifically regulates genes and proteins. This study supports the potential usage of TTFM extracts for the development of anti-cancer drugs.

A fatty acid-rich fraction of an endolichenic fungus Phoma sp. suppresses immune checkpoint markers via AhR/ARNT and ESR1

Lung cancer has the highest mortality rates worldwide. The disease is caused by environmental pollutants, smoking, and many other factors. Recent treatments include immunotherapeutics, which have shown some success; however, the search for new therapeutics is ongoing. Endolichenic fungi produce a whale of a lot of secondary metabolites, the therapeutic effects of which are being evaluated. Here, we used a crude extract and subfractions of the endolichenic fungus, Phoma sp. (EL006848), isolated from the Pseudevernia furfuracea. It was identified the fatty acid components, palmitic acid, stearic acid, and oleic acid, exist in subfractions E1 and E2. In addition, EL006848 and its fatty acids fractions suppressed benzo[a]pyrene (an AhR ligand)- induced expression of PD-L1 to inhibit the activity of multiple immune checkpoints. E2 subfraction, which had a higher fatty acid content than E1, downregulated expression of AhR/ARNT and several human transcription factors related to ESR1. Moreover, E2 showed a strong inhibitory effect on STAT3 expression and mild effect on NF-kB activity. These results suggest that fatty acids extracted from an endolichenic fungus can exert strong immunotherapeutic effects.

Unveiling the MUFA-Cancer Connection: Insights from Endogenous and Exogenous Perspectives

Monounsaturated fatty acids (MUFAs) have been the subject of extensive research in the field of cancer due to their potential role in its prevention and treatment. MUFAs can be consumed through the diet or endogenously biosynthesized. Stearoyl-CoA desaturases (SCDs) are key enzymes involved in the endogenous synthesis of MUFAs, and their expression and activity have been found to be increased in various types of cancer. In addition, diets rich in MUFAs have been associated with cancer risk in epidemiological studies for certain types of carcinomas. This review provides an overview of the state-of-the-art literature on the associations between MUFA metabolism and cancer development and progression from human, animal, and cellular studies. We discuss the impact of MUFAs on cancer development, including their effects on cancer cell growth, migration, survival, and cell signaling pathways, to provide new insights on the role of MUFAs in cancer biology.

Role of Olive Bioactive Compounds in Respiratory Diseases

Respiratory diseases recently became the leading cause of death worldwide, due to the emergence of COVID-19. The pathogenesis of respiratory diseases is centred around inflammation and oxidative stress. Plant-based alongside synthetic drugs were considered as therapeutics due to their proven nutraceutical value. One such example is the olive, which is a traditional symbol of the MedDiet. Olive bioactive compounds are enriched with antioxidant, anti-inflammatory, anticancer and antiviral properties. However, there are few studies relating to the beneficial effect of olive bioactive compounds on respiratory diseases. A vague understanding of its molecular action, dosage and bioavailability limits its usefulness for clinical trials about respiratory infections. Hence, our review aims to explore olive bioactive compound's antioxidant, anti-inflammatory and antiviral properties in respiratory disease defence and treatment. Molecular insight into olive compounds' potential for respiratory system protection against inflammation and ensuing infection is also presented. Olive bioactive compounds mainly protect the respiratory system by subsiding proinflammatory cytokines and oxidative stress.

Garcinia oligantha: A comprehensive overview of ethnomedicine, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia oligantha Merr. is an ethnomedicine plant mainly distributed in Guangdong and Hainan, China. It has the effects of heat-clearing and detoxicating, which has been used by local ethnic minorities to treat a variety of diseases, including inflammation, internal heat, toothache and scald.

THE AIM OF THE REVIEW

This review summarizes and discusses the progress of the chemical compounds and biological activities of G. oligantha that have been studied in recent years to provide the direction for the prospective research and applications of G. oligantha.

MATERIALS AND METHODS

The relevant literature about G. oligantha was accessible from ancient Chinese medical books and records, theses, as well as major scientific databases such as Google Scholar, PubMed, Web of Science, ScienceDirect, SciFinder, Baidu Scholar and China National Knowledge Infrastructure (CNKI).

RESULTS

To date, more than 150 chemical compounds were isolated from this plant, including xanthones, volatile oil, fatty acid, benzofurane derivative and biphenyl compounds. Xanthones are the main bioactive compounds that exhibit diverse biological effects, such as antitumor, analgesic, anti-inflammatory, antioxidative, neuroprotective, antimalarial and antibacterial effects, which are consistent with its traditional uses as a folk medicine. Modern pharmacological studies show that these compounds participate in a variety of signaling pathways underlying different pathophysiologies, making them a valuable medicinal resource.

CONCLUSION

G. oligantha is an ethnomedicine with a long history. However, due to regional and cultural constraints, the popularisation and use of ethnomedicine are still limited. Modern pharmacological and chemical research suggest that G. oligantha contains a variety of bioactive compounds and showed diverse biological functions, which is worthy of comprehensive and in-depth research. This review summarizes and discusses the recent progress in studies on G. oligantha, looking forward to promote further research and sustainable development of folk medicinal plants.

Acacia Honey-derived Bioactive Compounds Exhibit Induction of p53-dependent Apoptosis in the MCF-7 Human Breast Cancer Cell Line

Background

Research studies have focused on discovering new anti-proliferative and pro-apoptotic agents derived from natural products from which honey constitutes a prominent candidate. The Acacia honey (AH) is known to display anticancer activity, but the mechanisms of action are still not well defined.

Objectives

Using in vitro and computational approaches, we aimed to assess the interaction among selected bioactive compounds derived from AH, with the apoptotic protein p53, which could trigger apoptosis.

Methods

The phytocompounds of AH were investigated via gas chromatography–mass spectrophotometry analysis. The cytotoxic effect and induced apoptosis on the MCF-7 breast cancer cell line were assessed by 3-(4,5-dimethylthiazolyl-2)-2,5 diphenyltetrazolium bromide and acridine orange-ethidium bromide staining approaches. The molecular docking analysis between AH compounds and p53 was carried out.

Results

The drug-likeness prediction revealed that most of the identified compounds meet Lipinski’s rules. We demonstrate that AH exerts an interesting cytotoxic effect in a dose-dependent manner against the MCF-7 cell line with IC50 5.053µg/mL. Significant cell alterations and notable induced apoptosis were detected when cells were treated with AH. The molecular docking analysis revealed that melezitose is among the most important potential bioactive compounds that interact with p53 leading to apoptosis. The binding affinity was −8.1 kcal/mol, and the closest molecular interactions in the active site included 10 residues, which could explain the potential biological activity.

Conclusion

This work sheds light on AH as a significant source of bioactive chemicals with potential for promoting apoptosis that may be exploited as an alternative therapy for breast cancer.

Extra-Virgin Olive Oil and Its Minor Compounds Influence Apoptosis in Experimental Mammary Tumors and Human Breast Cancer Cell Lines

Simple Summary

Breast cancer is a disease influenced by dietetic factors, such as the type and amount of lipids in a diet. In this work, we aimed to elucidate the different effects of two high-fat diets on the histopathological and molecular characteristics of mammary tumors in an experimental model. Animals fed with a diet high in extra-virgin olive oil (EVOO), compared to those fed with a diet high in seed oil, developed tumors with less aggressiveness and proliferation. Tumor molecular analyses of several cell death pathways also suggested an effect of EVOO in this process. In vitro experiments indicated the role of EVOO minor compounds on the effects of this oil. Obtaining insights into the influence and the mechanisms of action of dietary compounds are necessary to understand the relevance that dietetic habits from childhood may have on health and the risk of disease.

Abstract

Breast cancer is the most common malignancy among women worldwide. Modifiable factors such as nutrition have a role in its etiology. In experimental tumors, we have observed the differential influence of high-fat diets in metabolic pathways, suggesting a different balance in proliferation/apoptosis. In this work, we analyzed the effects of a diet high in n-6 polyunsaturated fatty acids (PUFA) and a diet high in extra-virgin olive oil (EVOO) on the histopathological features and different cell death pathways in the dimethylbenz(a)anthracene-induced breast cancer model. The diet high in n-6 PUFA had a stimulating effect on the morphological aggressiveness of tumors and their proliferation, while no significant differences were found in groups fed the EVOO-enriched diet in comparison to a low-fat control group. The high-EVOO diet induced modifications in proteins involved in several cell death pathways. In vitro analysis in different human breast cancer cell lines showed an effect of EVOO minor compounds (especially hydroxytyrosol), but not of fatty acids, decreasing viability while increasing apoptosis. The results suggest an effect of dietary lipids on tumor molecular contexts that result in the modulation of different pathways, highlighting the importance of apoptosis in the interplay of survival processes and how dietary habits may have an impact on breast cancer risk.

Glyoxalase-1-Dependent Methylglyoxal Depletion Sustains PD-L1 Expression in Metastatic Prostate Cancer Cells: A Novel Mechanism in Cancer Immunosurveillance Escape and a Potential Novel Target to Overcome PD-L1 Blockade Resistance

Simple Summary

Metastatic prostate cancer (mPCa) is a well-known lethal condition. One of the mechanisms through which PCa cells become so aggressive is the avoidance of immune surveillance that further fosters cell growth, invasion, and migration. PD-L1/PD-1 axis plays a crucial role in inhibiting cytotoxic T cells and maintaining an immunosuppressive cancer microenvironment. Hence, targeting PD-L1/PD-1 axis represents a potential way to control mPCa. Unfortunately, mPCa patients do not respond to PD-L1/PD-1 axis blockade, focusing the research to understand the possible underpinning mechanisms. Our results provide a novel pathway taking part in cancer immunosurveillance escape and in the above-mentioned immunotherapy resistance, which provides the basis for additional studies aimed at developing novel therapeutic opportunities, possibly also in combination with antibodies blocking PD-L1/PD-1 axis.

Abstract

Metastatic prostate cancer (mPCa) is a disease for which to date there is not curative therapy. Even the recent and attractive immunotherapeutic approaches targeting PD-L1, an immune checkpoint protein which helps cancer cells to escape from immunosurveillance, have proved ineffective. A better understanding of the molecular mechanisms contributing to keep an immunosuppressive microenvironment associated with tumor progression and refractoriness to PD-L1 inhibitors is urgently needed. In the present study, by using gene silencing and specific activators or scavengers, we demonstrated, in mPCa cell models, that methylglyoxal (MG), a potent precursor of advanced glycation end products (AGEs), especially 5-hydro-5-methylimidazolone (MG-H1), and its metabolizing enzyme, glyoxalase 1 (Glo1), contribute to maintain an immunosuppressive microenvironment through MG-H1-mediated PD-L1 up-regulation and to promote cancer progression. Moreover, our findings suggest that this novel mechanism might be responsible, at least in part, of mPCa resistance to PD-L1 inhibitors, such as atezolizumab, and that targeting it may sensitize cells to this PD-L1 inhibitor. These findings provide novel insights into the mechanisms of mPCa immunosurveillance escape and help in providing the basis to foster in vivo research toward novel therapeutic strategies for immunotherapy of mPCa.