The influence of peroxisome proliferator-activated receptor γ (PPARγ) ligands on cancer cell tumorigenicity

Analysis of arsenic-modulated expression of hypothalamic estrogen receptor, thyroid receptor, and peroxisome proliferator-activated receptor gamma mRNA and simultaneous mitochondrial morphology and respiration rates in the mouse

Arsenic has been identified as an environmental toxicant acting through various mechanisms, including the disruption of endocrine pathways. The present study assessed the ability of a single intraperitoneal injection of arsenic, to modify the mRNA expression levels of estrogen- and thyroid hormone receptors (ERα,β; TRα,β) and peroxisome proliferator-activated receptor gamma (PPARγ) in hypothalamic tissue homogenates of prepubertal mice in vivo. Mitochondrial respiration (MRR) was also measured, and the corresponding mitochondrial ultrastructure was analyzed. Results show that ERα,β, and TRα expression was significantly increased by arsenic, in all concentrations examined. In contrast, TRβ and PPARγ remained unaffected after arsenic injection. Arsenic-induced dose-dependent changes in state 4 mitochondrial respiration (St4). Mitochondrial morphology was affected by arsenic in that the 5 mg dose increased the size but decreased the number of mitochondria in agouti-related protein- (AgRP), while increasing the size without affecting the number of mitochondria in pro-opiomelanocortin (POMC) neurons. Arsenic also increased the size of the mitochondrial matrix per host mitochondrion. Complex analysis of dose-dependent response patterns between receptor mRNA, mitochondrial morphology, and mitochondrial respiration in the neuroendocrine hypothalamus suggests that instant arsenic effects on receptor mRNAs may not be directly reflected in St3-4 values, however, mitochondrial dynamics is affected, which predicts more pronounced effects in hypothalamus-regulated homeostatic processes after long-term arsenic exposure.

Differential Tumor Gene Expression Profiling of Patients With Prostate Adenocarcinoma on the Basis of BMI

PURPOSE

An increased BMI is linked to increased prostate adenocarcinoma incidence and mortality. Baseline tumor gene expression profiling (GEP) can provide a comprehensive picture of the biological processes related to treatment response and disease progression. We interrogate and validate the underlying differences in tumor GEP on the basis of BMI in patients with prostate adenocarcinoma.

METHODS

The inclusion criteria consisted of histologically confirmed prostate adenocarcinoma and the availability of RNA sequencing data obtained from treatment-naïve primary prostate tissue. RNA sequencing was performed by a Clinical Laboratory Improvement Amendments-certified laboratory (Tempus or Caris Life Sciences). The Tempus cohort was used for interrogation and the Caris cohort for validation. Patients were stratified on the basis of BMI at the time of prostate cancer diagnosis: BMI-high (BMIH; BMI ≥30) and BMI-low (BMIL; BMI <30). Differential gene expression analysis between the two cohorts was conducted using the DEseq2 pipeline. The resulting GEPs were further analyzed using Gene Set Enrichment software to identify pathways that exhibited enrichment in each cohort.

RESULTS

Overall, 102 patients were eligible, with 60 patients in the Tempus cohort (BMIL = 38, BMIH = 22) and 42 patients in the Caris cohort (BMIL = 24, BMIH = 18). Tumor tissues obtained from patients in the BMIL group exhibited higher expression of genes associated with inflammation pathways. BMIH displayed increased expression of genes involved in pathways such as heme metabolism and androgen response.

CONCLUSION

Our study shows the upregulation of distinct genomic pathways in BMIL compared with BMIH patients with prostate cancer. These hypothesis-generating data could explain different survival outcomes in both groups and guide personalized therapy for men with prostate cancer.

Potential molecular biomarkers for the diagnosis and prognosis of bladder cancer

Bladder cancer (BC) is a common malignant tumor of urinary system, which can be divided into muscle-invasive BC (MIBC) and nonmuscle-invasive BC (NMIBC). The number of BC patients has been gradually increasing currently. At present, bladder tumours are diagnosed and followed-up using a combination of cystoscopic examination, cytology and histology. However, the detection of early grade tumors, which is much easier to treat effectively than advanced stage disease, is still insufficient. It frequently recurs and can progress when not expeditiously diagnosed and monitored following initial therapy for NMIBC. Treatment strategies are totally different for different stage diseases. Therefore, it is of great practical significance to study new biomarkers for diagnosis and prognosis. In this review, we summarize the current state of biomarker development in BC diagnosis and prognosis prediction. We retrospectively analyse eight diagnostic biomarkers and eight prognostic biomarkers, in which CK, P53, PPARγ, PTEN and ncRNA are emphasized for discussion. Eight molecular subtype systems are also identified. Clinical translation of biomarkers for diagnosis, prognosis, monitoring and treatment will hopefully improve outcomes for patients. These potential biomarkers provide an opportunity to diagnose tumors earlier and with greater accuracy, and help identify those patients most at risk of disease recurrence.

Integrated network pharmacology and experimental verification to explore the potential mechanism of San Ying decoction for treating triple-negative breast cancer

Traditional Chinese medicine (TCM) has been used to treat triple-negative breast cancer (TNBC), a breast cancer subtype with poor prognosis. Clinical studies have verified that the Sanyingfang formula (SYF), a TCM prescription, has obvious effects on inhibiting breast cancer recurrence and metastasis, prolonging patient survival, and reducing clinical symptoms. However, its active ingredients and molecular mechanisms are still unclear. In this study, the active ingredients of each herbal medicine composing SYF and their target proteins are obtained from the Traditional Chinese Medicine Systems Pharmacology database. Breast cancer-related genes are obtained from the GeneCards database. Major targets and pathways related to SYF treatment in breast cancer are identified by analyzing the above data. By conducting molecular docking analysis, we find that the active ingredients quercetin and luteolin bind well to the key targets KDR1, PPARG, SOD1, and VCAM1. In vitro experiments verify that SYF can reduce the proliferation, migration, and invasion ability of TNBC cells. Using a TNBC xenograft mouse model, we show that SYF could delay tumor growth and effectively inhibit the occurrence of breast cancer lung metastasis in vivo. PPARG, SOD1, KDR1, and VCAM1 are all regulated by SYF and may play important roles in SYF-mediated inhibition of TNBC recurrence and metastasis.

Abscisic acid signaling through LANCL2 and PPARγ induces activation of p38MAPK resulting in dormancy of prostate cancer metastatic cells

Prostate cancer (PCa) is one the most common malignancies in men. The high incidence of bone metastasis years after primary therapy suggests that disseminated tumor cells must become dormant, but maintain their ability to proliferate in the bone marrow. Abscisic acid (ABA) is a stress response molecule best known for its regulation of seed germination, stomal opening, root shoot growth and other stress responses in plants. ABA is also synthesized by mammalian cells and has been linked to human disease. The aim of the present study was to examine the role of ABA in regulating tumor dormancy via signaling through lanthionine synthetase C‑like protein 2 (LANCL2) and peroxisome proliferator activated receptor γ (PPARγ) receptors. ABA signaling in human PCa cell lines was studied using targeted gene knockdown (KD), western blotting, quantitative PCR, cell proliferation, migration, invasion and soft agar assays, as well as co‑culture assays with bone marrow stromal cells. The data demonstrated that ABA signaling increased the expression of p21, p27 and p16, while inhibiting viability, migration, invasion and colony size in a reversable manner without toxicity. ABA also induced p38MAPK activation and NR2F1 signaling. Targeted gene KD of LANCL2 and PPARγ abrogated the cellular responses to ABA. Taken together, these data demonstrate that ABA may induce dormancy in PCa cell lines through LANCL2 and PPARγ signaling, and suggest novel targets to manage metastatic PCa growth.

Involvement of the aryl hydrocarbon receptor (AhR) in the mechanism of action of elastin-derived peptide (VGVAPG) and its impact on neurosteroidogenesis

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor from the family of basic helix-loop-helix transcription factors. Several studies have indicated an important role of AhR signaling pathways in senescence, aging, and neurodegenerative diseases. During aging, elastin is degraded and elastin-derived peptides (EDPs) are formed. EDPs have been detected in human blood, serum, and cerebrospinal fluid. Literature data suggest a role of EDPs in the development of neurodegenerative diseases. However, the impact of EDPs on the AhR signaling pathway has never been investigated. Therefore, the aim of our paper was to study the role of AhR in the mechanism of action of the VGVAPG peptide (one of the EDPs) in mouse primary astrocytes in vitro. Our experiments have shown that AhR plays an important role in the EDP mechanism of action in a model of mouse primary astrocytes. Moreover, due to the involvement of Sirt3, Pparγ, AhR, Glb1, Nf-κb1, Ece1, Ide, and Nepr genes and the production and release of neurosteroids, VGVAPG can accelerate the development of neurodegenerative diseases in which the proper metabolism of astrocytes is crucial. Furthermore, our studies have proved that AhR is likely involved in the co-control of the Sirt1, Glb1, Nf-κb1, Ece1, and Nepr expression in astrocytes.

PPARG, GNG12, and CD19 are potential independent predictors of central nerve recurrence in childhood acute lymphoblastic leukemia

OBJECTIVE

To identify biomarkers that can predict the recurrence of the central nervous system (CNS) in children with acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

The transcriptome and clinical data of ALL in children were downloaded from the TARGET database. Transcriptome data were analyzed by bioinformatics method to identify core (hub) genes and establish a risk assessment model. Univariate Cox analysis was performed on each clinical data, and multivariate Cox regression analysis was performed on the obtained results and risk score. The children ALL phase I samples from TARGET database were used for validation.

RESULTS

Univariate multivariate Cox analysis of 10 hub genes identified showed that PPARG (HR = 0.78, 95%CI = 0.67-0.91, p = 0.007), CD19 (HR = 1.15, 95%CI = 1.05-1.26, p = 0.003) and GNG12 (HR = 1.25, 95%CI = 1.04-1.51, p = 0.017) had statistical differences. The risk score was statistically significant in univariate (HR = 3.06, 95%CI = 1.30-7.19, p = 0.011) and multivariate (HR = 1.81, 95%CI = 1.16-2.32, p = 0.046) Cox regression analysis. The survival analysis results of the high and low-risk groups were different when the validation dataset was substituted into the model (p = 0.018). Then, we constructed a Nomogram which had a concordance index of survival prediction of 0.791(95%CI= 0.779-0.803). In addition, the CNS involvement grading status at first diagnosis CNS3 vs. CNS1 (HR = 5.74, 95%CI = 2.01-16.4, p = 0.001), T cell vs B cell (HR = 1.63, 95% CI = 1.06-2.49, p = 0.026) were also statistically significant.

CONCLUSIONS

PPARG, GNG12, and CD19 may be predictors of CNS relapse in childhood ALL.

Therapeutic strategies targeting AMPK-dependent autophagy in cancer cells

Macroautophagy is a health-modifying process of engulfing misfolded or aggregated proteins or damaged organelles, coating these proteins or organelles into vesicles, fusion of vesicles with lysosomes to form autophagic lysosomes, and degradation of the encapsulated contents. It is also a self-rescue strategy in response to harsh environments and plays an essential role in cancer cells. AMP-activated protein kinase (AMPK) is the central pathway that regulates autophagy initiation and autophagosome formation by phosphorylating targets such as mTORC1 and unc-51 like activating kinase 1 (ULK1). AMPK is an evolutionarily conserved serine/threonine protein kinase that acts as an energy sensor in cells and regulates various metabolic processes, including those involved in cancer. The regulatory network of AMPK is complicated and can be regulated by multiple upstream factors, such as LKB1, AKT, PPAR, SIRT1, or noncoding RNAs. Currently, AMPK is being investigated as a novel target for anticancer therapies based on its role in macroautophagy regulation. Herein, we review the effects of AMPK-dependent autophagy on tumor cell survival and treatment strategies targeting AMPK.

Immune Checkpoint Inhibitors, Small-Molecule Immunotherapies and the Emerging Role of Neutrophil Extracellular Traps in Therapeutic Strategies for Head and Neck Cancer

Immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of many cancer types, including head and neck cancers (HNC). When checkpoint and partner proteins bind, these send an "off" signal to T cells, which prevents the immune system from destroying tumor cells. However, in HNC, and indeed many other cancers, more people do not respond and/or suffer from toxic effects than those who do respond. Hence, newer, more effective approaches are needed. The challenge to durable therapy lies in a deeper understanding of the complex interactions between immune cells, tumor cells and the tumor microenvironment. This will help develop therapies that promote lasting tumorlysis by overcoming T-cell exhaustion. Here we explore the strengths and limitations of current ICI therapy in head and neck squamous cell carcinoma (HNSCC). We also review emerging small-molecule immunotherapies and the growing promise of neutrophil extracellular traps in controlling tumor progression and metastasis.

Targeting lipid-sensing nuclear receptors PPAR (α, γ, β/δ): HTVS and molecular docking/dynamics analysis of pharmacological ligands as potential pan-PPAR agonists

The global prevalence of obesity-related systemic disorders, including non-alcoholic fatty liver disease (NAFLD), and cancers are rapidly rising. Several of these disorders involve peroxisome proliferator-activated receptors (PPARs) as one of the key cell signaling pathways. PPARs are nuclear receptors that play a central role in lipid metabolism and glucose homeostasis. They can activate or suppress the genes responsible for inflammation, adipogenesis, and energy balance, making them promising therapeutic targets for treating metabolic disorders. In this study, an attempt has been made to screen novel PPAR pan-agonists from the ZINC database targeting the three PPAR family of receptors (α, γ, β/δ), using molecular docking and molecular dynamics (MD) simulations. The top scoring five ligands with strong binding affinity against all the three PPAR isoforms were eprosartan, canagliflozin, pralatrexate, sacubitril, olaparib. The ADMET analysis was performed to assess the pharmacokinetic profile of the top 5 molecules. On the basis of ADMET analysis, the top ligand was subjected to MD simulations, and compared with lanifibranor (reference PPAR pan-agonist). Comparatively, the top-scoring ligand showed better protein-ligand complex (PLC) stability with all the PPARs (α, γ, β/δ). When experimentally tested in in vitro cell culture model of NAFLD, eprosartan showed dose dependent decrease in lipid accumulation and oxidative damage. These outcomes suggest potential PPAR pan-agonist molecules for further experimental validation and pharmacological development, towards treatment of PPAR-mediated metabolic disorders.

Cannabidiol goes nuclear: The role of PPARγ

BACKGROUND

Cannabidiol (CBD) is one of the main phytocannabinoids found in Cannabis sativa. In contrast to Δ9-tetrahydrocannabinol, it has a low affinity for cannabinoid receptors CB1 and CB2, thereby it does not induce significant psychoactive effects. However, CBD may interact with other receptors, including peroxisome proliferator-activated receptor gamma (PPARγ). CBD is a PPARγ agonist and changes its expression. There is considerable evidence that CBD's effects are mediated by its interaction with PPARγ. So, we reviewed studies related to the interaction of CBD and PPARγ.

METHODS

In this comprehensive literature review, the term 'cannabidiol' was used in combination with the following keywords including 'PPARγ', 'Alzheimer's disease', 'Parkinson's disease', 'seizure', 'multiple sclerosis', 'immune system', 'cardiovascular system', 'cancer', and 'adipogenesis'. PubMed, Web of Science, and Google Scholar were searched until December 20, 2022. A total of 78 articles were used for the reviewing process.

RESULTS

CBD, via activation of PPARγ, promotes significant pharmacological effects. The present review shows that the effects of CBD on Alzheimer's disease and memory, Parkinson's disease and movement disorders, multiple sclerosis, anxiety and depression, cardiovascular system, immune system, cancer, and adipogenesis are mediated, at least in part, via PPARγ.

CONCLUSION

CBD not only activates PPARγ but also affects its expression in the body. It was suggested that the late effects of CBD are mediated via PPARγ activation. We suggested that CBD's chemical structure is a good backbone for developing new dual agonists. Combining it with other chemicals enhances their biological effectiveness while reducing their dosage. The present study indicated that PPARγ is a key target for CBD, and its activation by CBD should be considered in all future studies.

A positive feedback loop between ID3 and PPARγ via DNA damage repair regulates the efficacy of radiotherapy for rectal cancer

OBJECTIVE

To study the effect of inhibitor of differentiation 3 (ID3) on radiotherapy in patients with rectal cancer and to explore its primary mechanism.

METHODS

Cell proliferation and clonogenic assays were used to study the relationship between ID3 and radiosensitivity. Co-immunoprecipitation and immunofluorescence were performed to analyze the possible mechanism of ID3 in the radiosensitivity of colorectal cancer. At the same time, a xenograft tumor model of HCT116 cells in nude mice was established to study the effect of irradiation on the tumorigenesis of ID3 knockdown colorectal cancer cells in vivo. Immunohistochemistry was performed to analyze the relationship between ID3 expression and the efficacy of radiotherapy in 46 patients with rectal cancer.

RESULTS

Proliferation and clonogenic assays revealed that the radiosensitivity of colorectal cancer cells decreased with ID3 depletion through p53-independent pathway. With the decrease in ID3 expression, MDC1 was downregulated. Furthermore, the expression of ID3, MDC1, and γH2AX increased and formed foci after irradiation. ID3 interacted with PPARγ and form a positive feedback loop to enhance the effect of ID3 on the radiosensitivity of colorectal cancer. Irradiation tests in nude mice also confirmed that HCT116 cells with ID3 knockdown were more affected by irradiation. Immunohistochemical study showed that rectal cancer patients with low expression of ID3 had better radiotherapy efficacy.

CONCLUSIONS

ID3 and PPARγ influence the radiosensitivity of colorectal cancer cells by interacting with MDC1 to form a positive feedback loop that promotes DNA damage repair. Patients with low expression of ID3 who received neoadjuvant chemoradiotherapy can obtain a better curative effect.

Activation of PPAR-γ prevents TERT-mediated pulmonary vascular remodeling in MCT-induced pulmonary hypertension

Background

It has been demonstrated that elevated telomerase reverse transcriptase (TERT) expression or activity is implicated in pulmonary hypertension (PH). In addition, activation of peroxisome-proliferator-activated receptor γ (PPAR-γ) has been found to prevent PH progression. However, the molecular mechanism responsible for the protective effect of PPAR-γ activation on TERT expression in the pathogenesis of PH remains unknown. This study was performed to address these issues.

Methods

Intraperitoneal injection of monocrotaline (MCT) was used to establish PH. BIBR1532 was applied to inhibit the activity of telomerase. The right ventricular systolic pressure (RVSP) and histological analysis were used to detect the development of PH. The protein levels of p-Akt, t-Akt, c-Myc and TERT were determined by western blotting. Pharmacological inhibition of TERT by BIBR1532 effectively suppressed RVSP, RVHI and the WT% in MCT-induced PH rats.

Results

Pharmacological inhibition of Akt/c-Myc pathway by LY294002 diminished TERT upregulation, RVSP, RVHI and WT% in MCT-PH rats. Activation of PPAR-γ by pioglitazone inhibited p-Akt and c-Myc expressions and further downregulated TERT, thus to reduced RVSP, RVHI and WT% in MCT-treated PH rats.

Conclusions

In conclusion, TERT upregulation contributes to PH development in MCT-treated rats. Activation of PPAR-γ prevents pulmonary arterial remodeling through Akt/c-Myc/TERT axis suppression.

The role of peroxisome proliferator-activated receptors in the modulation of hyperinflammation induced by SARS-CoV-2 infection: A perspective for COVID-19 therapy

Coronavirus disease 2019 (COVID-19) is a severe respiratory disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that affects the lower and upper respiratory tract in humans. SARS-CoV-2 infection is associated with the induction of a cascade of uncontrolled inflammatory responses in the host, ultimately leading to hyperinflammation or cytokine storm. Indeed, cytokine storm is a hallmark of SARS-CoV-2 immunopathogenesis, directly related to the severity of the disease and mortality in COVID-19 patients. Considering the lack of any definitive treatment for COVID-19, targeting key inflammatory factors to regulate the inflammatory response in COVID-19 patients could be a fundamental step to developing effective therapeutic strategies against SARS-CoV-2 infection. Currently, in addition to well-defined metabolic actions, especially lipid metabolism and glucose utilization, there is growing evidence of a central role of the ligand-dependent nuclear receptors and peroxisome proliferator-activated receptors (PPARs) including PPARα, PPARβ/δ, and PPARγ in the control of inflammatory signals in various human inflammatory diseases. This makes them attractive targets for developing therapeutic approaches to control/suppress the hyperinflammatory response in patients with severe COVID-19. In this review, we (1) investigate the anti-inflammatory mechanisms mediated by PPARs and their ligands during SARS-CoV-2 infection, and (2) on the basis of the recent literature, highlight the importance of PPAR subtypes for the development of promising therapeutic approaches against the cytokine storm in severe COVID-19 patients.

Could dietary erucic acid lower risk of brain tumors? An epidemiological look to Chinese population with implications for prevention and treatment

Erucic acid, an omega-9 monounsaturated fatty acid present in Brassicaceae plants (rapeseed and mustard oils) is highly consumed by the Chinese population and according to several global survey studies, its highest levels are encountered in the Chinese women's milk. Erucic acid is an activating ligand of the transcription factor PPARδ and an inhibitor of the transcriptional activity of PPARγ, which drive tumorigenesis of glioblastomas and medulloblastomas. In this theoretical review, we propose that erucic acid in diet may associate with the risk of brain tumors. High grade brain tumors including medulloblastomas in children and glioblastomas in adults have devastating consequences for human health and the latter tumors are practically incurable. CONCORD-3 epidemiological study recently published in 2021 revealed a low ratio of medulloblastomas in the pediatric age group and also a low ratio of glioblastomas in adults in the Chinese population. It is certain that such profound differences can not be attributed to a single genetic factor or a single nurture pattern. It is very likely that multiple hereditary, nutritional and environmental factors are responsible for these lower ratios; yet here we propose that erucic acid may be one of the contributing factors. If future epidemiological studies and animal models show antitumor activity of erucic acid regarding brain neoplasias, it can be utilized as a preventive strategy for populations possessing very high risks to develop brain tumors such as those harbouring hereditary syndromes increasing the vulnerability to develop such malignancies.

Brown adipocytes promote epithelial mesenchymal transition of neuroblastoma cells by inducing PPAR-γ/UCP2 expression

Neuroblastoma (NB) is an embryonic malignant tumour of the sympathetic nervous system, and current research shows that activation of brown adipose tissue accelerates cachexia in cancer patients. However, the interaction between brown adipose tissues and NB remains unclear. The study aimed to investigate the effect of brown adipocytes in the co-culture system on the proliferation and migration of NB cells. Brown adipocytes promoted the proliferation and migration of Neuro-2a, BE(2)-M17, and SH-SY5Y cells under the co-culture system, with an increase of the mRNA and protein levels of UCP2 and PPAR-γ in NB cells. The UCP2 inhibitor genipin or PPAR-γ inhibitor T0090709 inhibited the migration of NB cells induced by brown adipocytes. Genipin or siUCP2 upregulated the expression of E-cadherin, and downregulated the expression of N-cadherin and vimentin in NB cells. We suggest that under co-cultivation conditions, NB cells can activate brown adipocytes, which triggers changes in various genes and promotes the proliferation and migration of NB cells. The PPAR-γ/UCP2 pathway is involved in the migration of NB cells caused by brown adipocytes.

Molecular mechanism of benign biliary stricture inhibition by rosiglitazone-activated peroxisome proliferator-activated receptor gamma

OBJECTIVE

The aim of this study was to investigate whether rosiglitazone-activated peroxisome proliferator-activated receptor gamma can inhibit the occurrence of benign biliary stricture and further elucidate the relevant molecular signaling mechanism.

METHODS

The primary cultured rat biliary fibroblasts following experiments were performed using within the fifth generation cells, which were separated from the bile ducts of Sprague-Dawley rats. The primary cultured rat biliary fibroblasts were co-cultured with 10 ng/mL transforming growth factor-beta 1 for stimulating collagen formation. Competent cells were transfected with siRNA that specifically target Smad3 or connective tissue growth factor to inhibit the expression of the corresponding proteins. The cells were incubated with 10 μmol/L rosiglitazone to activate peroxisome proliferator-activated receptor gamma. The cells were incubated with 10 μmol/L GW9662 in the pretreatment session to inactivate peroxisome proliferator-activated receptor gamma. ELISA was used to determine the levels of connective tissue growth factor and type I collagen in the cell supernatant. Western blotting was used to detect the levels of intracellular p-Smad3/t-Smad3.

RESULTS

Rosiglitazone-activated peroxisome proliferator-activated receptor gamma inhibited the secretion of type I collagen induced by transforming growth factor-beta 1. Peroxisome proliferator-activated receptor gamma inhibitor GW9662 could significantly reverse the rosiglitazone-triggered inhibition of transforming growth factor-beta 1-induced type I collagen secretion by suppressing peroxisome proliferator-activated receptor gamma activation (p<0.01). Furthermore, we also found that the activation of peroxisome proliferator-activated receptor gamma was accompanied by the inhibition of transforming growth factor-beta 1-induced Smad3 phosphorylation (p<0.01), increased connective tissue growth factor expression (p<0.01), and production of type I collagen (p<0.01), all of which effects elicited by rosiglitazone could be reversed by peroxisome proliferator-activated receptor gamma inhibitor GW9662.

CONCLUSION

Peroxisome proliferator-activated receptor gamma activated by rosiglitazone inhibits the transforming growth factor-beta1 -induced phosphorylation of Smad3 and the increased connective tissue growth factor expression as well as inhibits the secretion of type I collagen in biliary fibroblasts.

The Potential Role of PPARs in the Fetal Origins of Adult Disease

The fetal origins of adult disease (FOAD) hypothesis holds that events during early development have a profound impact on one’s risk for the development of future adult disease. Studies from humans and animals have demonstrated that many diseases can begin in childhood and are caused by a variety of early life traumas, including maternal malnutrition, maternal disease conditions, lifestyle changes, exposure to toxins/chemicals, improper medication during pregnancy, and so on. Recently, the roles of Peroxisome proliferator-activated receptors (PPARs) in FOAD have been increasingly appreciated due to their wide variety of biological actions. PPARs are members of the nuclear hormone receptor subfamily, consisting of three distinct subtypes: PPARα, β/δ, and γ, highly expressed in the reproductive tissues. By controlling the maturation of the oocyte, ovulation, implantation of the embryo, development of the placenta, and male fertility, the PPARs play a crucial role in the transition from embryo to fetus in developing mammals. Exposure to adverse events in early life exerts a profound influence on the methylation pattern of PPARs in offspring organs, which can affect development and health throughout the life course, and even across generations. In this review, we summarize the latest research on PPARs in the area of FOAD, highlight the important role of PPARs in FOAD, and provide a potential strategy for early prevention of FOAD.

Signaling pathways in the regulation of cancer stem cells and associated targeted therapy

Cancer stem cells (CSCs) are defined as a subpopulation of malignant tumor cells with selective capacities for tumor initiation, self-renewal, metastasis, and unlimited growth into bulks, which are believed as a major cause of progressive tumor phenotypes, including recurrence, metastasis, and treatment failure. A number of signaling pathways are involved in the maintenance of stem cell properties and survival of CSCs, including well-established intrinsic pathways, such as the Notch, Wnt, and Hedgehog signaling, and extrinsic pathways, such as the vascular microenvironment and tumor-associated immune cells. There is also intricate crosstalk between these signal cascades and other oncogenic pathways. Thus, targeting pathway molecules that regulate CSCs provides a new option for the treatment of therapy-resistant or -refractory tumors. These treatments include small molecule inhibitors, monoclonal antibodies that target key signaling in CSCs, as well as CSC-directed immunotherapies that harness the immune systems to target CSCs. This review aims to provide an overview of the regulating networks and their immune interactions involved in CSC development. We also address the update on the development of CSC-directed therapeutics, with a special focus on those with application approval or under clinical evaluation.

Bone marrow mesenchymal stem cell-derived extracellular vesicles facilitate endometrial injury repair by carrying the E3 ubiquitin ligase WWP1

Bone marrow mesenchymal stem cells-derived extracellular vesicles (BMSC-EVs) relieve endometrial injury. This study aimed to elucidate the BMSC-EV mechanism in alleviating endometrial injury. Endometrial injury model in vivo was induced using 95% ethanol, and endometrial epithelial cells (EECs) treated with mifepristone were applied as an endometrial injury model in vitro. After BMSCs and BMSC-EVs were isolated and identified, the BMSC-EV function was evaluated by hematoxylin-eosin and Masson staining, immunohistochemistry, quantitative real-time PCR, Cell Counting Kit-8 assay, flow cytometry, enzyme-linked immunosorbent assay, and Transwell and tubule formation assays. The BMSC-EV mechanism was assessed using Western blot, ubiquitination, and cycloheximide-chase assays. After isolation and identification, BMSC-EVs were effective in endometrial injury repair in vivo and facilitated EEC proliferation and repressed cell apoptosis in vitro; the EEC supernatants accelerated human umbilical vein endothelial cell proliferation, migration, and invasion and facilitated angiogenesis after endometrial injury in vitro. For the BMSC-EV mechanism, E3 ubiquitin ligase WWP1 in BMSC-EVs mediated the ubiquitination of peroxisome proliferator-activated receptor gamma (PPARγ), thus relieving the PPARγ inhibition on vascular endothelial growth factor expression. Furthermore, the WWP1 in BMSC-EVs alleviated endometrial injury in vitro and in vivo. BMSC-EVs facilitated endometrial injury repair by carrying WWP1.

Cannabinoids and PPAR Ligands: The Future in Treatment of Polycystic Ovary Syndrome Women with Obesity and Reduced Fertility

Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases. Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition. The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth.

Thiazolidine-2,4-dione derivative exhibits antitumoral effect and reverts behavioral and metabolic changes in a model of glioblastoma

The aim of the present study was to evaluate the anti-glioma activity of 3-(4-fluorobenzyl)-5-(4-methoxybenzylidene)thiazolidine-2,4-dione (AV23) in a preclinical model of glioblastoma, as well as behavioral parameters and toxicological profile. The implantation of C6 cells in the left striatum of male Wistar rats was performed by stereotaxic surgery. After recovery, animals were treated with vehicle (canola oil) or AV23 (10 mg/kg/day) intragastrically for 15 days. It was found that AV23 reduced tumor volume by 90%. Serum biochemical parameters such as triglycerides, cholesterol, HDL-cholesterol, LDL-cholesterol, albumin, aspartate aminotransferase, urea, creatinine and total proteins were not changed; however, there was a slight increase in alanine aminotransferase. The compound AV23 reverted the hypoglycemia and the reduction in body weight caused by glioblastoma. Additionally, AV23 was able to revert the reduction of locomotion caused by the tumor implantation. Therefore, the compound AV23 can be considered a promising candidate in the treatment of glioblastoma.

PPARγ activation inhibits PDGF-induced pulmonary artery smooth muscle cell proliferation and migration by modulating TERT

Vascular remodeling is a significant feature of pulmonary artery hypertension (PAH), and is characterized by abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Telomerase reverse transcriptase (TERT), as a determining factor for controlling telomerase activity, has been proven to be associated with cell proliferation. This study aims to explore whether TERT mediates the proliferation and migration of PASMCs and the underlying molecular mechanism. Primary PASMCs from Sprague-Dawley (SD) rats were used in this experiment. Cell proliferation and migration were evaluated by Cell Counting Kit-8, EdU incorporation assay and transwell assay, respectively. Telomerase activity was assessed with a rat TE ELISA kit. Small interfering RNA (siRNA) transfection was conducted to silence c-MYC expression. The protein levels of p-Akt, c-MYC, PPARγ and TERT were determined through western blotting. Our work demonstrates that PDGF upregulated TERT expression and telomerase activation by activating Akt and upregulating of c-MYC in PASMCs. Inhibition of Akt with LY294002, knockdown of c-MYC by siRNA or suppression of telomerase activity with BIBR1532 repressed PDGF-induced PASMC proliferation and migration. Furthermore, activation of peroxisome proliferator-activated receptor γ (PPARγ) with pioglitazone suppressed PDGF-induced TERT expression and telomerase activation, leading to inhibition of PASMC proliferation and migration.

Peroxisome proliferator-activated receptor gamma as a therapeutic target for hepatocellular carcinoma: Experimental and clinical scenarios

Hepatocellular carcinoma (HCC) is the most common type of liver cancer worldwide. Viral hepatitis is a significant risk factor for HCC, although metabolic syndrome and diabetes are more frequently associated with the HCC. With increasing prevalence, there is expected to be > 1 million cases annually by 2025. Therefore, there is an urgent need to establish potential therapeutic targets to cure this disease. Peroxisome-proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that plays a crucial role in the patho-physiology of HCC. Many synthetic agonists of PPARγ suppress HCC in experimental studies and clinical trials. These synthetic agonists have shown promising results by inducing cell cycle arrest and apoptosis in HCC cells and preventing the invasion and metastasis of HCC. However, some synthetic agonists also pose severe side effects in addition to their therapeutic efficacy. Thus natural PPARγ agonists can be an alternative to exploit this potential target for HCC treatment. In this review, the regulatory role of PPARγ in the pathogenesis of HCC is elucidated. Furthermore, the experimental and clinical scenario of both synthetic and natural PPARγ agonists against HCC is discussed. Most of the available literature advocates PPARγ as a potential therapeutic target for the treatment of HCC.

Quercetin Inhibits KBM7R Cell Proliferation through Wnt/β-Catenin Signaling

Background

Tyrosine kinase inhibitors could treat chronic myelogenous leukemia (CML) effectively, but they have no effect on patients with T315I mutation. It is necessary to find drugs to overcome the resistance. Quercetin (Qu) is a kind of bioflavonoid with an antitumor effect. In this study, we observed the effect of Qu on proliferation and Wnt/β-catenin pathway in KBM7R cells, an imatinib-resistant cell with T315I mutation.

Methods

The IC50 of Qu was detected by trypan blue staining. The KBM7R cell apoptosis and cycle were detected through the method of flow cytometry (FCM). The expression of the related mRNA and protein was evaluated by means of an RT-PCR assay and western blot in KBM7 (sensitive to IM) and KBM7R cells.

Results

These results showed that in the KBM7R cell, the proliferation inhibition effect was increased after 48 h administration with different Qu concentrations. The IC50 to Qu was 241.7 μmol/L. The different doses of Qu (50, 100, and 200 μmol/L) would raise apoptosis and depress the cell cycle at the G1 phase. Dealing with a median Qu concentration (100 μmol/L) for 48 h, the mRNA and the protein level of caspase-3, caspase-8, and caspase-9 along with p21 and p27 raised compared with the control. The median concentration of Qu could inhibit both the mRNA and protein levels of GSK-3β, β-catenin, and Lef-1 in the Wnt/β-catenin signal pathway and also the downstream targets PPAR-δ and cyclin D1 in both KBM7 and KBM7R cells.

Conclusions

Our findings suggest that Qu could inhibit proliferation, induce apoptosis, and arrest the cell cycle on IM-resistant KBM7R cells with T315I mutation. And this effect could be related with the inhibition of the Wnt/β-catenin signal pathway and downstream targets.

The Preparation of Gen-NH2-MCM-41@SA Nanoparticles and Their Anti-Rotavirus Effects

Genistein (Gen), a kind of natural isoflavone drug monomer with poor water solubility and low oral absorption, was incorporated into oral nanoparticles with a new mesoporous carrier material, NH₂-MCM-41, which was synthesized by copolycondensation. When the ratio of Gen to NH₂-MCM-41 was 1:0.5, the maximum adsorption capacity of Gen was 13.15%, the maximum drug loading was 12.65%, and the particle size of the whole core–shell structure was in the range of 370 nm–390 nm. The particles were characterized by a Malvern particle size scanning machine, XRD, Fourier transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption and desorption. Finally, Gen-NH₂-MCM-41 was encapsulated by sodium alginate (SA), and the chimerism of this material, denoted as GEN-NH₂-MCM-41@SA, was investigated. In vitro release experiments showed that, after 5 h in artificial colon fluid (pH = 8.0), the cumulative release reached 99.56%. In addition, its anti-rotavirus (RV) effect showed that the maximum inhibition rate was 62.24% at a concentration of 30 μM in RV-infected Caco-2 cells, and it significantly reduced the diarrhea rate and diarrhea index in an RV-infected-neonatal mice model at a dose of 0.3 mg/g, which was better than the results of Gen. Ultimately, Gen-NH₂-MCM-41@SA was successfully prepared, which solves the problems of low solubility and poor absorption and provides an experimental basis for the application of Gen in the clinical treatment of RV infection.

Lipid Metabolism and Cancer

Lipid metabolism is involved in the regulation of numerous cellular processes, such as cell growth, proliferation, differentiation, survival, apoptosis, inflammation, movement, membrane homeostasis, chemotherapy response, and drug resistance. Reprogramming of lipid metabolism is a typical feature of malignant tumors. In a variety of cancers, fat uptake, storage and fat production are up-regulated, which in turn promotes the rapid growth, invasion, and migration of tumors. This paper systematically summarizes the key signal transduction pathways and molecules of lipid metabolism regulating tumors, and the role of lipid metabolism in programmed cell death. In conclusion, understanding the potential molecular mechanism of lipid metabolism and the functions of different lipid molecules may facilitate elucidating the mechanisms underlying the occurrence of cancer in order to discover new potential targets for the development of effective antitumor drugs.

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

MicroRNAs and Corresponding Targets in Esophageal Cancer as Shown In Vitro and In Vivo in Preclinical Models

Squamous cell carcinoma of the esophagus is associated with a dismal prognosis. Therefore, identification of new targets and implementation of new treatment modalities are issues of paramount importance. Based on a survey of the literature, we identified microRNAs conferring antitumoral activity in preclinical in vivo experiments. In the category of miRs targeting secreted factors and transmembrane receptors, four miRs were up-regulated and 10 were down-regulated compared with five out of nine in the category transcription factors, and six miRs were down-regulated in the category enzymes, including metabolic enzymes. The down-regulated miRs have targets which can be inhibited by small molecules or antibody-related entities, or re-expressed by reconstitution therapy. Up-regulated miRs have targets which can be reconstituted with small molecules or inhibited with antagomirs.

A Bibliometric Analysis Based on Web of Science: Current Perspectives and Potential Trends of SMAD7 in Oncology

Background: The number of publications on SMAD7 in the field of oncology is increasing rapidly with an upward tendency. In most cases, the mechanisms of carcinogenesis usually relate to disorders of signaling activity. Considering the crucial role of SMAD7 in the crosstalk of multiple signaling pathways, it is necessary to clarify and define the dominant research topics, core authors, and their cumulative research contributions, as well as the cooperative relationships among documents or researchers.

Methods: Altogether, 3477 documents were retrieved from the Web of Science Core Collection with the following criteria: TS= (SMAD7 OR SMAD7-protein OR Small-Mothers-Against-Decapentaplegic-7) refined by WEB OF SCIENCE CATEGORY (ONCOLOGY) AND [excluding] PUBLICATION YEARS (2021) AND DOCUMENT TYPES (ARTICLE OR REVIEW) AND LANGUAGES (ENGLISH) AND WEB OF SCIENCE INDEX (Web of Science Core Collection, SCI), and the timespan of 2011–2020. Bibliometric visualization analysis was conducted with CiteSpace and VOSviewer.

Results: The number of documents grew each year. A total of 2703 articles and 774 reviews were identified from 86 countries/regions, 3524 organizations, 928 journals, and 19,745 authors. China was the most prolific country, with 1881 documents. Contributions from China, the United States, and Germany were the most substantial. The most influential author was Lan Huiyao at The Chinese University of Hong Kong, with 24 publications and 2348 total citations. The bibliometric analysis showed that multilateral cooperation among diverse institutions or investigators was beneficial to high-quality outputs. The keyword “PPAR-gamma” exhibited the strongest burst in recent years, suggesting a potent research focus in the future.

Conclusion: Research on SMAD7 in oncology is continuously developing. Bibliometrics is an interesting tool to present the characteristics of publication years, main authors, and productive organizations in a visualized way. It is worth mentioning that a prospective focus might be the specific mechanism of the interaction of PPAR-gamma with SMAD7 in oncology. In all, bibliometric analysis provides an overview and identifies potential research trends for further studies in this academic field.

Potential Therapeutic Effects of PPAR Ligands in Glioblastoma

Glioblastoma (GB), also known as grade IV astrocytoma, represents the most aggressive form of brain tumor, characterized by extraordinary heterogeneity and high invasiveness and mortality. Thus, a great deal of interest is currently being directed to investigate a new therapeutic strategy and in recent years, the research has focused its attention on the evaluation of the anticancer effects of some drugs already in use for other diseases. This is the case of peroxisome proliferator-activated receptors (PPARs) ligands, which over the years have been revealed to possess anticancer properties. PPARs belong to the nuclear receptor superfamily and are divided into three main subtypes: PPAR-α, PPAR-β/δ, and PPAR-γ. These receptors, once activated by specific natural or synthetic ligands, translocate to the nucleus and dimerize with the retinoid X receptors (RXR), starting the signal transduction of numerous genes involved in many physiological processes. PPARs receptors are activated by specific ligands and participate principally in the preservation of homeostasis and in lipid and glucose metabolism. In fact, synthetic PPAR-α agonists, such as fibrates, are drugs currently in use for the clinical treatment of hypertriglyceridemia, while PPAR-γ agonists, including thiazolidinediones (TZDs), are known as insulin-sensitizing drugs. In this review, we will analyze the role of PPARs receptors in the progression of tumorigenesis and the action of PPARs agonists in promoting, or not, the induction of cell death in GB cells, highlighting the conflicting opinions present in the literature.

Targeting Breast Cancer and Their Stem Cell Population through AMPK Activation: Novel Insights

Despite some significant advancements, breast cancer has become the most prevalent cancer in the world. One of the main reasons for failure in treatment and metastasis has been attributed to the presence of cancer initiating cells—cancer stem cells. Consequently, research is now being focussed on targeting cancer cells along with their stem cell population. Non-oncology drugs are gaining increasing attention for their potent anticancer activities. Metformin, a drug commonly used to treat type 2 diabetes, is the best example in this regard. It exerts its therapeutic action by activating 5′ adenosine monophosphate-activated protein kinase (AMPK). Activated AMPK subsequently phosphorylates and targets several cellular pathways involved in cell growth and proliferation and the maintenance of stem-like properties of cancer stem cells. Therefore, AMPK is emerging as a target of choice for developing effective anticancer drugs. Vanadium compounds are well-known PTP inhibitors and AMPK activators. They find extensive applications in treatment of diabetes and obesity via PTP1B inhibition and AMPK-mediated inhibition of adipogenesis. However, their role in targeting cancer stem cells has not been explored yet. This review is an attempt to establish the applications of insulin mimetic vanadium compounds for the treatment of breast cancer by AMPK activation and PTP1B inhibition pathways.

Cytochrome b561 Serves as a Potential Prognostic Biomarker and Target for Breast Cancer

PURPOSE

Cytochrome b561 (CYB561) is a transmembrane protein and participates in ascorbate recycling and iron homeostasis. However, its role in breast cancer remains unclear.

PATIENTS AND METHODS

In this study, we explored the expression pattern and prognostic value of CYB561 in breast cancer through The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), PrognoScan and Kaplan-Meier Plotter and confirmed its mRNA expression in human breast cell lines. LinkedOmics, Metascape and Gene Expression Profiling Interactive Analysis (GEPIA2) databases were applied to investigate the co-expression genes and construct microRNA (miRNA) networks associated with CYB561. The correlations between CYB561 and immune infiltration cells and genes were also illustrated.

RESULTS

The CYB561 expression was upregulated in breast cancer tissues and cell lines and significantly correlated with the clinical features of breast cancer patients. High CYB561 expression was associated with poor survival and was an independent risk factor for overall and disease-specific survival. Functional enrichment analysis showed that CYB561 and its co-expressed genes were mainly enriched in lipid biosynthetic process, Wnt signaling pathway, Hippo signaling pathway, etc. The miRNA network analysis suggested that hsa-miR-497 was negatively correlated with CYB561 expression and was predicted to direct target CYB561. CYB561 expression was positively correlated with infiltrating levels of CD4+ T cells, neutrophils and dendritic cells in breast cancer. Subsequent analysis found that B cells could predict the outcome of breast cancer. Also, CYB561 showed strong correlations with diverse immune marker sets in breast cancer.

CONCLUSION

CYB561 may serve as a potential prognostic biomarker and target for breast cancer. Our findings laid foundation for future research on molecular mechanisms of CYB561 in breast cancer.

Cancer Stem Cells Contribute to Drug Resistance in Multiple Different Ways

Many tumors are resistant to conventional cancer therapies because a tumor is composed of heterogeneous cell population. Especially, subpopulation of cancer stem cells, which have self-renewal and differentiation properties and responsible for the tumor initiation, is generally considered resistant to chemo-, radio-, and immune therapy. Understanding the mechanism of drug resistance in cancer stem cells should lead to establish more effective therapeutic strategies. Actually, different molecular mechanisms are conceivable for cancer stem cells acquiring drug resistance. These mechanisms include not only cytoplasmic signaling pathways but also the intercellular communications in the tumor microenvironment. Recently, a great deal of successful reports challenged to elucidate the mechanisms of drug resistance and to develop novel treatments targeting cancer stem cells.

Fish and the Thyroid: A Janus Bifrons Relationship Caused by Pollutants and the Omega-3 Polyunsaturated Fatty Acids

Benefits of the omega-3 polyunsaturated fatty acids (PUFA) on a number of clinical disorders, including autoimmune diseases, are widely reported in the literature. One major dietary source of PUFA are fish, particularly the small oily fish, like anchovy, sardine, mackerel and others. Unfortunately, fish (particularly the large, top-predator fish like swordfish) are also a source of pollutants, including the heavy metals. One relevant heavy metal is mercury, a known environmental trigger of autoimmunity that is measurable inside the thyroid. There are a number of interactions between the omega-3 PUFA and thyroid hormones, even at the level of the thyroid hormone transport proteins. Concerning the mechanisms behind the protection from/amelioration of autoimmune diseases, including thyroiditis, that are caused by the omega-3 PUFA, one can be the decreased production of chemokines, a decrease that was reported in the literature for other nutraceuticals. Recent studies point also to the involvement of resolvins. The intracellular increase in resolvins is associated with the tissue protection from inflammation that was observed in experimental animals after coadministration of omega-3 PUFA and thyroid hormone. After having presented data on fish consumption at the beginning, we conclude our review by presenting data on the market of the dietary supplements/nutraceuticals. The global omega-3 products market was valued at USD 2.10 billion in 2020, and was projected to go up at a compound annual growth rate of 7.8% from 2020 to 2028. Among supplements, fish oils, which are derived mainly from anchovies, are considered the best and generally safest source of omega-3. Taking into account (i) the anti-autoimmunity and anti-cancer properties of the omega-3 PUFA, (ii) the increasing incidence of both autoimmune thyroiditis and thyroid cancer worldwide, (iii) the predisposing role for thyroid cancer exerted by autoimmune thyroiditis, and (iv) the risk for developing metabolic and cardiovascular disorders conferred by both elevated/trendwise elevated serum TSH levels and thyroid autoimmunity, then there is enough rationale for the omega-3 PUFA as measures to contrast the appearance and/or duration of Hashimoto's thyroiditis as well as to correct the slightly elevated serum TSH levels of subclinical hypothyroidism.

Hydroxysafflor yellow A inhibits the proliferation, migration, and invasion of colorectal cancer cells through the PPARγ/PTEN/Akt signaling pathway

The natural compound Hydroxysafflor yellow A (HSYA) has been demonstrated to exert anti-cancer effect on multiple cancers. This study aimed to clarify the role of HSYA in inhibiting colorectal cancer (CRC) in vitro and the underlying mechanisms. Different concentrations of HSYA (0, 25, 50, and 100 μM) was exposed to HCT116 CRC cells, then cell proliferation, apoptosis, migration, and invasion were estimated by colony formation assay, TUNEL staining, wound-healing, and transwell assays, respectively. Western blotting assay was utilized to observe the expression of proteins involved in cell apoptosis, migration, and peroxisome proliferator-activated receptor γ (PPARγ)/PTEN/Akt signaling, including PCNA, Bax, Bcl-2, cleaved-caspase3, E-cadherin, N-cadherin, vimentin, PPARγ, and phosphorylated (p)-Akt. HCT116 cells that treated with 100 μM HSYA were also pre-treated with PPARγ antagonist, GW9662, or knockdown with PPARγ using short hairpin (sh)-RNA, to down-regulate PPARγ expression. Then, the above functional analysis was repeated. Results demonstrated that HSYA (25, 50 and 100 μM) significantly reduced HCT116 cell viability, but had no effect on the cell viability of human normal intestinal epithelial cell HIEC. HSYA also inhibited colony formation, migration, and invasion but promoted apoptosis of HCT116 cell in a concentration-dependent manner. Besides, the PPARγ/PTEN/Akt signaling was activated upon HSYA treatment. Finally, GW9662 and PPARγ knockdown blocked all the effects of HSYA on HCT116 cells. In conclusion, HSYA could exhibit anti-cancer effect on CRC via activating PPARγ/PTEN/Akt signaling, thereby inhibiting cells proliferation, migration, and invasion in vitro.

Morin inhibits the transformation of fibroblasts towards myofibroblasts through regulating "PPAR-γ-glutaminolysis-DEPTOR" pathway in pulmonary fibrosis

Morin, a natural flavonoid exists in many foods and dietary plants, owns good bioactivities. Herein, we investigated its effect on pulmonary fibrosis (PF), and further explored the mechanisms. Results showed that morin remarkably improved the pathologic alterations, and inhibited the transformation of fibroblasts towards myofibroblasts in lungs of mice with bleomycin-induced PF as well as TGF-β1 or hypoxia-stimulated NIH-3T3 cells. Mechanistic studies revealed that morin activated peroxisome proliferator activated receptor-gamma (PPAR-γ), and GW9662 or siPPAR-γ significantly weakened the inhibition of morin on the transformation of NIH-3T3 cells. Furthermore, morin restricted glutaminolysis by down-regulating the level of glutaminase 1 (GLS1), which was confirmed by glutamine deprivation, and GLS1 overexpression. Replenishment of metabolite α-ketoglutarate (α-KG) and 2-hydroxyglutarate (2-HG) inhibited morin-prevented transformation of fibroblasts, but neither TGF-β1 nor hypoxia could induce the transformation of IDH2-knockdown fibroblasts, suggesting 2-HG was directly involved in the action of morin. Then, ubiquitination of DEPTOR was demonstrated to be prevented by morin, which was attributed to KDM4A, an enzyme inactivated by 2-HG, and leucine as well as KDM4A inhibitor obstructed the effect of morin. Finally, the mechanisms of morin were further confirmed in vivo. Collectively, morin inhibited PF through intervening in "PPAR-γ-glutaminolysis-DEPTOR" signals, and subsequent restriction on the transformation of fibroblasts towards myofibroblasts.

Moracin D induces apoptosis in prostate cancer cells via activation of PPAR gamma/PKC delta and inhibition of PKC alpha

Herein, apoptotic mechanism of Moracin D was explored in prostate cancer cells in association with peroxisome proliferator-activated receptor gamma (PPAR-γ)-related signaling involved in lipid metabolism. Moracin D augmented cytotoxicity and sub G1 population in PC3 and DU145 prostate cancer cells, while DU145 cells were more susceptible to Moracin D than PC3 cells. Moracin D attenuated the expression of caspase-3, poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2), and B-cell lymphoma-extra-large (Bcl-xL) in DU145 cells. Consistently, Moracin D significantly augmented the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in DU145 cells. Interestingly, Moracin D activated PPAR-γ and phospho-protein kinase C delta (p-PKC-δ) and inhibited phospho-protein kinase C alpha (p-PKC-α) in DU145 cells. Furthermore, STRING bioinformatic analysis reveals that PPAR-γ interacts with nuclear factor-κB (NF-κB) that binds to PKC-α/PKC-δ or protein kinase B (AKT) or extracellular signal-regulated kinase (ERK). Indeed, Moracin D decreased phosphorylation of NF-κB, ERK, and AKT in DU145 cells. Conversely, PPAR-γ inhibitor GW9662 reduced the apoptotic ability of Moracin D to activate caspase 3 and PARP in DU145 cells. Taken together, these findings provide a novel insight that activation of PPAR-γ/p-PKC-δ and inhibition of p-PKC-α are critically involved in Moracin D-induced apoptosis in DU145 prostate cancer cells.

Adipose mesenchymal stem cells and gingival mesenchymal stem cells have a comparable effect in endothelium repair

Restenosis is the major factor influencing the long-term success rate of angioplasty and stent implantation and effective strategies to prevent restenosis remain limited. Mesenchymal stem cells (MSCs) are pluripotent stem cells capable of self-renewal and multidirectional differentiation, which may be able to promote endothelium repair, thereby reducing restenosis. The present study aimed to evaluate the effects of adipose MSCs (AMSCs) and gingival MSCs (GMSCs) on endothelium repair. MSCs were isolated from two human tissue types, namely adipose tissue and gingival tissue, and the effects of AMSCs and GMSCs in ex vivo endothelium repair and on vascular smooth muscle cell (SMC) growth were examined. To compare the feasibility of using AMSCs and GMSCs for the repair of endothelium damage in endothelial cell (EC) damage and vasoproliferative disorders, an ex vivo model of endothelium repair in a co-culture system was developed. It was indicated that AMSCs and GMSCs expressed characteristic MSC markers (CD105 and CD166). 3H-thymidine incorporation in the co-culture group of AMSCs and SMCs in the presence of ECs was lower compared with that in the GMSC and SMC co-culture group. The protein expression level of proliferating cell nuclear antigen in the co-culture group of AMSCs and SMCs in the presence of ECs were lower compared with that in the GMSC and SMC co-culture group. After co-culture with ECs for 5 days, 25.71±3.08% of AMSCs began to express CD31 protein and 20.06±2.09% of GMSCs began to express CD31 protein. Furthermore, anti-VEGF antibody was able to inhibit MSC differentiation. Collectively, the present results suggested that seeding of AMSCs had a stronger effect to inhibit the proliferation and migration of SMCs compared with GMSCs.

PPARγ Targets-Derived Diagnostic and Prognostic Index for Papillary Thyroid Cancer

Simple Summary

Through targeted next-generation sequencing of thyroid cancer-related genes in monozygotic twins with papillary thyroid cancer (PTC), we identified common variants of the gene encoding peroxisome proliferator activated receptor gamma (PPARG). Notably, the expression levels of PPARγ target genes were frequently deregulated in PTC compared to benign tissues and were closely associated with disease-specific survival (DSS) outcomes in a TCGA-PTC cohort. Machine learning-powered personalized scoring index comprising 10 PPARγ targets, termed as PPARGi, achieved a near-perfect accuracy in distinguishing cancers from benign tissues, and further identified a small subpopulation of patients at high-risk across different profiling platforms.

Abstract

In most cases, papillary thyroid cancer (PTC) is highly curable and associated with an excellent prognosis. Yet, there are several clinicopathological features that lead to a poor prognosis, underscoring the need for a better genomic strategy to refine prognostication and patient management. We hypothesized that PPARγ targets could be potential markers for better diagnosis and prognosis due to the variants found in PPARG in three pairs of monozygotic twins with PTC. Here, we developed a 10-gene personalized prognostic index, designated PPARGi, based on gene expression of 10 PPARγ targets. Through scRNA-seq data analysis of PTC tissues derived from patients, we found that PPARGi genes were predominantly expressed in macrophages and epithelial cells. Machine learning algorithms showed a near-perfect performance of PPARGi in deciding the presence of the disease and in selecting a small subset of patients with poor disease-specific survival in TCGA-THCA and newly developed merged microarray data (MMD) consisting exclusively of thyroid cancers and normal tissues.

Troglitazone-Induced PRODH/POX-Dependent Apoptosis Occurs in the Absence of Estradiol or ERβ in ER-Negative Breast Cancer Cells

Simple Summary

PRODH/POX (proline dehydrogenase/proline oxidase) is a mitochondrial enzyme that catalyzes proline degradation generating reactive oxygen species (ROS). Estrogens limit proline availability for PRODH/POX by stimulating collagen biosynthesis. It has been considered that estrogens determine efficiency of troglitazone (TGZ)-induced PRODH/POX-dependent apoptosis in breast cancer cells. The studies were performed in wild-type and PRODH/POX-silenced estrogen-dependent MCF-7 cells and estrogen-independent MDA-MB-231 cells. DNA and collagen biosynthesis were determined by radiometric method, ROS production was measured by fluorescence assay, protein expression was determined by Western blot and proline concentration by LC/MS analysis. We found that: i/TGZ-induced apoptosis in MDA-MB-231 occurs only in the absence of estradiol or ERβ, ii/the process is mediated by PRODH/POX, iii/and is facilitated by proline availability for PRODH/POX by TGZ-dependent inhibition of collagen biosynthesis (proline utilizing process). The data suggest that combined TGZ and anti-estrogen treatment could be considered in experimental therapy of ER negative breast cancers.

Abstract

The impact of estradiol on troglitazone (TGZ)-induced proline dehydrogenase/proline oxidase (PRODH/POX)-dependent apoptosis was studied in wild-type and PRODH/POX-silenced estrogen receptor (ER) dependent MCF-7 cells and ER-independent MDA-MB-231 cells. DNA and collagen biosynthesis were determined by radiometric method, prolidase activity evaluated by colorimetric method, ROS production was measured by fluorescence assay. Protein expression was determined by Western blot and proline concentration by LC/MS analysis. PRODH/POX degrades proline yielding reactive oxygen species (ROS). Estrogens stimulate collagen biosynthesis utilizing free proline and limiting its availability for PRODH/POX-dependent apoptosis. TGZ cytotoxicity was highly pronounced in wild-type MDA-MB-231 cells cultured in medium without estradiol or in the cells cultured in medium with estradiol but deprived of ERβ (by ICI-dependent degradation), while in PRODH/POX-silenced cells the process was not affected. The TGZ cytotoxicity was accompanied by increase in PRODH/POX expression, ROS production, expression of cleaved caspase-3, caspase-9 and PARP, inhibition of collagen biosynthesis, prolidase activity and decrease in intracellular proline concentration. The phenomena were not observed in PRODH/POX-silenced cells. The data suggest that TGZ-induced apoptosis in MDA-MB-231 cells cultured in medium without estradiol or deprived of ERβ is mediated by PRODH/POX and the process is facilitated by proline availability for PRODH/POX by TGZ-dependent inhibition of collagen biosynthesis. It suggests that combined TGZ and antiestrogen treatment could be considered in experimental therapy of estrogen receptor negative breast cancers.

Treatment of acromegaly by rosiglitazone via upregulating 15-PGDH in both pituitary adenoma and liver

Rosiglitazone, a synthetic peroxisome proliferator-activated receptor γ (PPARγ) ligand, has been reported to reduce growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in 10 patients with acromegaly. However, the mechanisms remain unknown. Here, we reveal that PPARγ directly enhances 15-hydroxyprostaglandin dehydrogenase (15-PGDH) expression, whose expression is decreased and negatively correlates with tumor size in acromegaly. Rosiglitazone decreases GH production and promotes apoptosis and autophagy in GH3 and primary somatotroph adenoma cells and suppresses hepatic GH receptor (GHR) expression and IGF-1 secretion in HepG2 cells. Activating the PGE2/cAMP/PKA pathway directly increases GHR expression. Rosiglitazone suppresses tumor growth and decreases GH and IGF-1 levels in mice inoculated subcutaneously with GH3 cells. The above effects are all dependent on 15-PGDH expression. Rosiglitazone as monotherapy effectively decreases GH and IGF-1 levels in all nineteen patients with active acromegaly. Evidence suggests that rosiglitazone may be an alternative pharmacological approach for acromegaly by targeting both pituitary adenomas and liver.

Phillygenin inhibits the inflammation and apoptosis of pulmonary epithelial cells by activating PPARγ signaling via downregulation of MMP8

Acute lung injury (ALI) is often responsible for the high morbidity of critically ill patients. The present study aimed to investigate whether phillygenin (PHI) can inhibit inflammation and apoptosis of pulmonary epithelial cells by activating peroxisome proliferator-activated receptor γ (PPARγ) signaling. The in vitro model of ALI was established using lipopolysaccharide (LPS) and PHI was used to treat the LPS-induced cells. Cell viability was assessed using the MTT assay and the concentration levels of the inflammatory factors were detected by ELISA. Western blotting and reverse transcription-quantitative PCR were conducted to measure the expression levels of the inflammation- and apoptosis-associated proteins. The MMP8-overexpression plasmid was transfected into LPS-induced cells, which were treated with PHI treatment and the expression levels of PPARγ were detected via western blotting. PHI treatment suppressed the induction of inflammation and apoptosis of LPS-induced BEAS-2B cells. Furthermore, the expression levels of MMP8 in BEAS-2B cells induced by LPS were decreased following PHI treatment. Following transfection of the MMP8 overexpression plasmid into the LPS-induced BEAS-2B cells and subsequent treatment of these cells with PHI, the expression levels of PPARγ were decreased. In conclusion, it was shown that PHI inhibited the inflammation and apoptosis of pulmonary epithelial cells by activating PPARγ signaling via downregulating MMP8. These data may provide valuable information for future studies exploring the therapeutic effects of PHI for ALI.

Molecular Iodine/Cyclophosphamide Synergism on Chemoresistant Neuroblastoma Models

Neuroblastoma (Nb), the most common extracranial tumor in children, exhibited remarkable phenotypic diversity and heterogeneous clinical behavior. Tumors with MYCN overexpression have a worse prognosis. MYCN promotes tumor progression by inducing cell proliferation, de-differentiation, and dysregulated mitochondrial metabolism. Cyclophosphamide (CFF) at minimum effective oral doses (metronomic therapy) exerts beneficial actions on chemoresistant cancers. Molecular iodine (I₂) in coadministration with all-trans retinoic acid synergizes apoptosis and cell differentiation in Nb cells. This work analyzes the impact of I₂ and CFF on the viability (culture) and tumor progression (xenografts) of Nb chemoresistant SK-N-BE(2) cells. Results showed that both molecules induce dose-response antiproliferative effects, and I₂ increases the sensibility of Nb cells to CFF, triggering PPARγ expression and acting as a mitocan in mitochondrial metabolism. In vivo oral I₂/metronomic CFF treatments showed significant inhibition in xenograft growth, decreasing proliferation (Survivin) and activating apoptosis signaling (P53, Bax/Bcl-2). In addition, I₂ decreased the expression of master markers of malignancy (MYCN, TrkB), vasculature remodeling, and increased differentiation signaling (PPARγ and TrkA). Furthermore, I₂ supplementation prevented loss of body weight and hemorrhagic cystitis secondary to CFF in nude mice. These results allow us to propose the I₂ supplement in metronomic CFF treatments to increase the effectiveness of chemotherapy and reduce side effects.

SIRT1/PGC-1α/PPAR-γ Correlate With Hypoxia-Induced Chemoresistance in Non-Small Cell Lung Cancer

Resistance is the major cause of treatment failure and disease progression in non-small cell lung cancer (NSCLC). There is evidence that hypoxia is a key microenvironmental stress associated with resistance to cisplatin, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), and immunotherapy in solid NSCLCs. Numerous studies have contributed to delineating the mechanisms underlying drug resistance in NSCLC; nevertheless, the mechanisms involved in the resistance associated with hypoxia-induced molecular metabolic adaptations in the microenvironment of NSCLC remain unclear. Studies have highlighted the importance of posttranslational regulation of molecular mediators in the control of mitochondrial function in response to hypoxia-induced metabolic adaptations. Hypoxia can upregulate the expression of sirtuin 1 (SIRT1) in a hypoxia-inducible factor (HIF)-dependent manner. SIRT1 is a stress-dependent metabolic sensor that can deacetylate some key transcriptional factors in both metabolism dependent and independent metabolic pathways such as HIF-1α, peroxisome proliferator-activated receptor gamma (PPAR-γ), and PPAR-gamma coactivator 1-alpha (PGC-1α) to affect mitochondrial function and biogenesis, which has a role in hypoxia-induced chemoresistance in NSCLC. Moreover, SIRT1 and HIF-1α can regulate both innate and adaptive immune responses through metabolism-dependent and -independent ways. The objective of this review is to delineate a possible SIRT1/PGC-1α/PPAR-γ signaling-related molecular metabolic mechanism underlying hypoxia-induced chemotherapy resistance in the NSCLC microenvironment. Targeting hypoxia-related metabolic adaptation may be an attractive therapeutic strategy for overcoming chemoresistance in NSCLC.

The Emerging Role of COX-2, 15-LOX and PPARγ in Metabolic Diseases and Cancer: An Introduction to Novel Multi-target Directed Ligands (MTDLs)

Emerging evidence supports an intertwining framework for the involvement of different inflammatory pathways in a common pathological background for a number of disorders. Of importance are pathways involving arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). Both enzyme activities and their products are implicated in a range of pathophysiological processes encompassing metabolic impairment leading to adipose inflammation and the subsequent vascular and neurological disorders, in addition to various pro- and antitumorigenic effects. A further layer of complexity is encountered by the disparate, and often reciprocal, modulatory effect COX-2 and 15-LOX activities and metabolites exert on each other or on other cellular targets, the most prominent of which is peroxisome proliferator-activated receptor gamma (PPARγ). Thus, effective therapeutic intervention with such multifaceted disorders requires the simultaneous modulation of more than one target. Here, we describe the role of COX-2, 15-LOX, and PPARγ in cancer and complications of metabolic disorders, highlight the value of designing multi-target directed ligands (MTDLs) modifying their activity, and summarizing the available literature regarding the rationale and feasibility of design and synthesis of these ligands together with their known biological effects. We speculate on the potential impact of MTDLs in these disorders as well as emphasize the need for structured future effort to translate these early results facilitating the adoption of these, and similar, molecules in clinical research.

Xeroderma Pigmentosum group D suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via the PPARγ pathway

Xeroderma Pigmentosum group D (XPD) gene has been shown to suppress hepatocellular carcinoma (HCC) progression, but its mechanism remains not fully understood. ETS-related gene (ERG) is generally known as an oncogenic gene. This study aimed to explore whether XPD regulated HCC cell proliferation, apoptosis and cell cycle by inhibiting ERG expression via the PPARγ pathway. The human hepatoma cells (HepG2) were transfected with the XPD overexpression vector (pEGFP-N2/XPD) or empty vector (pEGFP-N2). The PPARγ inhibitor GW9662 was used to determine whether XPD effects were mediated by activation of PPARγ pathway. Cell cycle and apoptosis were ascertained by flow cytometry, and cell viability was measured by MTT assay. Reverse transcription-polymerase chain reaction and Western blot were performed to determine the mRNA and protein levels. Overexpression of XPD significantly enhanced the expression of PPARγ and p-PPARγ, whereas it downregulated that of ERG and cdk7. Furthermore, XPD overexpression notably inhibited proliferation, promoted apoptosis and decreased the percentage of cells in the S + G2 phase of HepG2 cells. However, these effects of XPD overexpression were abrogated by GW9662. Collectively, XPD suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via activation of the PPARγ pathway.

A unique understanding of traditional medicine of pomegranate, Punica granatum L. and its current research status

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate, Punica granatum L., has been used in traditional medicine in China and several regions of the world including Ayurveda, Islamic, and Persian for the treatment of atherosclerosis, diabetes, hypertension, hyperlipidemia, and several types of cancer, as well as for peptic ulcer and oral diseases for hundreds of years. Presently, pomegranate is treated as both a "medicine food homology" herbal medicine and a healthy food supplemental product.

AIM OF THE STUDY

The aim of this work is to develop an overview of pomegranate in the context of the status of its traditional medicine theories, the spread along the Silk Road, ethnopharmacological uses, chemical compositions, pharmacological activities, toxicology, and the involved pathways.

MATERIALS AND METHODS

Information on P. granatum L. was acquired from published materials, including monographs on medicinal plants, ancient and modern recorded classical texts; and pharmacopoeias and electronic databases (PubMed, Science Direct, Web of Science, Google Scholar, CNKI, and Wanfang Data).

RESULTS

Pomegranate has been used in many traditional medical systems throughout history. It is widely cultivated in Central Asia and spread throughout China along the Silk Road. Many phytochemicals, such as tannins, organic acids, flavonoids, alkaloids, and volatile oils have been identified from different parts of pomegranate, these compounds have a wide range of activities, including antioxidant, antimicrobial, and anti-oncogenic properties, as well as conferring resistance to cerebrovascular disease. Furthermore, A summary of the four promising pharmacological pathways is provided.

CONCLUSIONS

The traditional uses, chemical compositions, pharmacological activities, and signaling pathways of pomegranate are summarized comprehensively in the review. It can be treated as a guidance for the future clinical and basic research. The information provided in this review will be very useful for further studies to develop novel therapeutic directions for application of pomegranate.

A nomogram combining PPARγ expression profiles and clinical factors predicts survival in patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with poor prognosis. Peroxisome proliferator-activated receptor γ (PPARγ) is involved in the development of various tumor types. However, its role in hepatocellular carcinoma (HCC) remains unclear. Multiple databases including The Cancer Genome Atlas, Gene Expression Omnibus and Kaplan-Meier plotter were used for bioinformatics analysis of the PPARγ gene or protein. Immunohistochemical labeling of tumor and adjacent normal tissues obtained from 125 patients with HCC was performed to analyze the relationship between PPARγ expression and overall survival (OS) rate. PPARγ was evaluated using functional enrichment analyses and Lasso regression was used to conduct a dimensionality reduction analysis of 43 clinical factors for HCC. An OS prognostic nomogram was then established using seven independent risk factors screened via Lasso regression. PPARγ expression in HCC tumor tissues was higher compared with that in normal liver tissues, and its high expression was associated with poor prognosis, as indicated by bioinformatics analysis. However, opposite results were obtained using the clinical specimens. Functional enrichment analysis indicated that PPARγ was enriched in the 'fatty acid metabolism' pathway. Lasso regression identified seven clinical factors associated with prognosis, including Tumor-Node-Metastasis stage, grade, vascular invasion, α fetoprotein, carbohydrate antigen 199, γ-glutamyl transpeptidase and the PPARγ protein. These seven clinical factors were to construct an OS prognostic nomogram. Overall, PPARγ was highly expressed in the livers of patients with HCC and can be included in an OS prognostic nomogram. However, the factors underlying the differential association of PPARγ expression with HCC prognosis in different datasets should be further investigated.