Clinical Significance of Peroxisome Proliferator-Activated Receptor γ and TRAP220 in Patients with Operable Colorectal Cancer

UCP2 as a Cancer Target through Energy Metabolism and Oxidative Stress Control

Despite numerous therapies, cancer remains one of the leading causes of death worldwide due to the lack of markers for early detection and response to treatment in many patients. Technological advances in tumor screening and renewed interest in energy metabolism have allowed us to identify new cellular players in order to develop personalized treatments. Among the metabolic actors, the mitochondrial transporter uncoupling protein 2 (UCP2), whose expression is increased in many cancers, has been identified as an interesting target in tumor metabolic reprogramming. Over the past decade, a better understanding of its biochemical and physiological functions has established a role for UCP2 in (1) protecting cells from oxidative stress, (2) regulating tumor progression through changes in glycolytic, oxidative and calcium metabolism, and (3) increasing antitumor immunity in the tumor microenvironment to limit cancer development. With these pleiotropic roles, UCP2 can be considered as a potential tumor biomarker that may be interesting to target positively or negatively, depending on the type, metabolic status and stage of tumors, in combination with conventional chemotherapy or immunotherapy to control tumor development and increase response to treatment. This review provides an overview of the latest published science linking mitochondrial UCP2 activity to the tumor context.

A review on the molecular mechanisms, the therapeutic treatment including the potential of herbs and natural products, and target prediction of obesity-associated colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer death worldwide. Obesity has been proven to be closely related to colorectal carcinogenesis. This review summarized the potential underlying mechanisms linking obesity to CRC in different aspects, including energy metabolism, inflammation, activities of adipokines and hormones. Furthermore, the potential therapeutic targets of obesity-associated CRC were predicted using network-based target analysis, with total predicted pathways not only containing previously reported pathways, but also putative signaling pathways pending for investigation. In addition, the current conventional therapeutic treatment options, plus the potential use of herbs and natural products in the management of obesity-associated CRC were also discussed. Taken together, the aim of this review article is to provide strong theoretical basis for future drug development, particularly herbs and natural products, in obesity-associated CRC.

Lycopene supplementation regulates the gene expression profile and fat metabolism of breeding hens

This study investigated the effects of lycopene on the gene expression profile and expression of genes related to fat metabolism of Xinghua breeding hens. Seven hundred and twenty healthy breeding hens were randomly assigned to four treatments; each treatment was replicated six times with 30 hens each. Broken rice and soybean meal were adopted for the basal diet and added with 0 (control group), 20, 40 and 80 mg/kg lycopene respectively. Gene expression profile of the liver induced by lycopene and expression of genes related to fat metabolism in hens liver and intestine were analysed after 42-day feeding trial including 7-day pre-feeding period and 35-day formal period. The genes involved in fat metabolism were analysed, and we found that lycopene significantly increased the expression of PGC1α, PPARα, RXRα and RARα in the liver, PPARγ, RXRα and RXRγ in the jejunum, and RARα in the duodenum (p < .05); reduced the expression of FABP1 and FABP10 in the liver, and FATP4 in the jejunum (p < .05). By analysing gene expression profile, 158 differentially expressed genes (DEGs) including 69 up-regulated genes and 89 down-regulated genes were obtained between control group and 40 mg/kg group. KEGG pathway analysis was performed on all DEGs, and 5 pathways were obtained. In conclusion, lycopene can affect the expression of related genes, and this may be one of the reasons that lycopene can regulate fat metabolism.

Activation of β2-Adrenergic Receptor Promotes Growth and Angiogenesis in Breast Cancer by Down-regulating PPARγ

Purpose

Chronic stress and related hormones are key in cancer progression. Peroxisome proliferator-activated receptor γ (PPARγ) and its agonists was reported that inducing anti-tumor effect. However, the function of PPARγ in pro-tumorigenic effects induced by chronic stress in breast cancer remains unknown. Herein, we have characterized a novel role of PPARγ and vascular endothelial growth factor (VEGF)/fibroblast growth factor 2 (FGF2) signals in breast cancer promoted by chronic stress.

Materials and Methods

We performed experiments in vivo and in vitro and used bioinformatics data to evaluate the therapeutic potential of PPARγ in breast cancer promoted by stress.

Results

Chronic stress significantly inhibited the PPARγ expression and promoted breast cancer in vivo. VEGF/FGF2-mediated angiogenesis increased in the chronic stress group compared to the control group. PPARγ agonist pioglitazone (PioG) injection offset the pro-tumorigenic effect of chronic stress. Moreover, specific β₂-adrenergic receptor (β₂R) antagonist ICI11-8551 inhibited the effect of chronic stress. In vitro, norepinephrine (NE) treatment had a similar tendency to chronic stress. The effect of NE was mediated by the β₂R/adenylate cyclase signaling pathway and suppressed by PioG. PPARγ suppressed VEGF/FGF2 through reactive oxygen species inhibition. Bioinformatics data confirmed that therewas a lowPPARγ expression in breast invasive carcinoma. Lower PPARγ was associated with a significantly worse survival.

Conclusion

β₂R activation induced by chronic stress and related hormones promotes growth and VEGF/FGF2-mediated angiogenesis of breast cancer by down-regulating PPARγ. Our findings hint that β receptor and PPARγ as two target molecules and the novel role for their agonists or antagonists as clinical medicine in breast cancer therapy

Expression and role of nuclear receptor coregulators in colorectal cancer

Colorectal cancer (CRC) is one of the most common human cancers and the cause of about 700000 deaths per year worldwide. Deregulation of the WNT/β-catenin pathway is a key event in CRC initiation. This pathway interacts with other nuclear signaling pathways, including members of the nuclear receptor superfamily and their transcription coregulators. In this review, we provide an overview of the literature dealing with the main coactivators (NCoA-1 to 3, NCoA-6, PGC1-α, p300, CREBBP and MED1) and corepressors (N-CoR1 and 2, NRIP1 and MTA1) of nuclear receptors and summarize their links with the WNT/β-catenin signaling cascade, their expression in CRC and their role in intestinal physiopathology.

Checkpoint-dependent phosphorylation of Med1/TRAP220 in response to DNA damage

Mediator complex subunit 1 (Med1)/Thyroid hormone receptor-associated protein 220 (TRAP220), an essential component of thyroid hormone receptor-associated proteins (TRAP)/mediator, plays important roles in hormone responses and tumorigenesis. However, the role of Med1 in the DNA damage response has not been studied. In this study, we found that DNA damage, resulted from γ-irradiation, ultraviolet (UV)-irradiation, or hydroxyurea, induced phosphorylation of Med1 in vivo. Phosphorylation of Med1 was abrogated by either caffeine or wortmannin treatment, suggesting that Med1 is phosphorylated through the DNA damage checkpoint pathway. A checkpoint kinase 1 (Chk1)/checkpoint kinase 2 (Chk2) consensus phosphorylation motif was identified at Serine 671 of Med1 and Ser671 motif was primarily phosphorylated by Chk2 in vitro. Moreover, the in vivo phosphorylation of Med1 was abrogated by a Chk2 inhibitor, and physical interaction between Chk2 and Med1 was observed, confirming that Chk2 is responsible for Med1 phosphorylation upon DNA damage. These results suggest that Med1 is a novel target for the DNA damage checkpoint pathway and may participate in the DNA damage response. Consistent with this notion, knockdown of Med1 expression caused a significant increase in cellular sensitivity to UV irradiation. Moreover, microarray analysis revealed that the UV-induced activation of the transcription of important regulators of cell cycle control and DNA repair, including p21, Gadd45, Rad50, DnaJ, and RecQL, was impaired upon Med1 knockdown. Taken together, our data suggest that Med1 is a novel target for Chk2-mediated phosphorylation and may play a role in cellular DNA damage responses by mediating proper induction of gene transcription upon DNA damage.

Obesity and colorectal cancer: molecular features of adipose tissue

The huge part of population in developed countries is overweight or obese. Obesity is often determined by body mass index (BMI) but new accurate methods and ratios have recently appeared to measure body fat or fat located in the intestines. Early diagnosis of obesity is crucial since it is considered an increasing colorectal cancer risk factor. On the one hand, colorectal cancer has been strongly associated with lifestyle factors. A diet rich in red and processed meats may increase colorectal cancer risk; however, high-fiber diets (grains, cereals and fruits) have been associated with a decreased risk of colorectal cancer. Other life-style factors associated with obesity that also increase colorectal cancer risk are physical inactivity, smoking and high alcohol intake. Cutting-edge studies reported that high-risk transformation ability of adipose tissue is due to production of different pro-inflammatory cytokines like IL-8, IL-6 or IL-2 and other enzymes like lactate dehydrogenase (LDH) and tumour necrosis factor alpha (TNFα). Furthermore, oxidative stress produces fatty-acid peroxidation whose metabolites possess very high toxicities and mutagenic properties. 4-hydroxy-2-nonenal (4-HNE) is an active compounds that upregulates prostaglandin E2 which is directly associated with high proliferative colorectal cancer. Moreover, 4-HNE deregulates cell proliferation, cell survival, differentiation, autophagy, senescence, apoptosis and necrosis via mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PIK3CA)—AKT and protein kinase C pathways. Other product of lipid peroxidation is malondialdehyde (MDA) being able to regulate insulin through WNT-pathway as well as having demonstrated its mutagenic capability. Accumulation of point mutation enables genomic evolution of colorectal cancer described in the model of Fearon and Vogelstein. In this review, we will summarize different determination methods and techniques to assess a truthfully diagnosis and we will explain some of the capabilities that performs adipocytes as the largest endocrine organ.

Update on genetics and diabetic retinopathy

Clinical risk factors for diabetic retinopathy (DR), such as duration of disease and degree of glucose control, do not adequately predict disease progression in individual patients, suggesting the presence of a genetic component. Multiple smaller studies have investigated genotype–phenotype correlations in genes encoding vascular endothelial growth factor, aldose reductase, the receptor for advanced glycation end products, and many others. In general, reported results have been conflicting, due to factors including small sample sizes, variations in study design, differences in clinical end points, and underlying genetic differences between study groups. At this time, there is no confirmed association with any risk allele reported. As we continue to collect data from additional studies, the role of genetics in DR may become more apparent.