Autophagic mechanisms in longevity intervention: role of natural active compounds

The term 'autophagy' literally translates to 'self-eating' and alterations to autophagy have been identified as one of the several molecular changes that occur with aging in a variety of species. Autophagy and aging, have a complicated and multifaceted relationship that has recently come to light thanks to breakthroughs in our understanding of the various substrates of autophagy on tissue homoeostasis. Several studies have been conducted to reveal the relationship between autophagy and age-related diseases. The present review looks at a few new aspects of autophagy and speculates on how they might be connected to both aging and the onset and progression of disease. Additionally, we go over the most recent preclinical data supporting the use of autophagy modulators as age-related illnesses including cancer, cardiovascular and neurodegenerative diseases, and metabolic dysfunction. It is crucial to discover important targets in the autophagy pathway in order to create innovative therapies that effectively target autophagy. Natural products have pharmacological properties that can be therapeutically advantageous for the treatment of several diseases and they also serve as valuable sources of inspiration for the development of possible new small-molecule drugs. Indeed, recent scientific studies have shown that several natural products including alkaloids, terpenoids, steroids, and phenolics, have the ability to alter a number of important autophagic signalling pathways and exert therapeutic effects, thus, a wide range of potential targets in various stages of autophagy have been discovered. In this review, we summarised the naturally occurring active compounds that may control the autophagic signalling pathways.

Individual susceptibility has a major impact on strong association between oxidative stress, defence systems and Parkinson's disease

Oxidative stress plays an important role in the degeneration of dopaminergic neurons, which causes Parkinson's disease (PD). Oxidative stress products, antioxidant and their balance have important roles in the development of oxidative stress-based PD. The impact of reactive oxygen species (ROS) and defence systems can be altered by genetic polymorphisms, and thus the risk of PD may also be affected. We aimed to investigate the possible association of individual susceptibility with the development of oxidative stress-based PD. For this purpose, we measured serum levels of folic acid, homocysteine, Vitamin B6 and B12 that play roles in folate-dependent one-carbon pathway, oxidant or antioxidant enzymes (NADPH oxidase, MnSOD, GPX), 8-OHdG and repair enzymes (OGG1, XRCC1 and MTH1) by ELISA, and analysed related gene polymorphisms by PCR-RFLP. XRCC1, ROS, NADPH and folic acid levels were found to be statistically higher in patients than controls. XRCC1, MnSOD and GPX activities were increased. We observed higher levels of 8-OHdG in patients with MnSOD and XRCC1 mutant genotypes and higher XRCC1 levels in patients with NOX p22 fox mutant genotypes rather than controls. We suggest that routinely clinical validation of major oxidative stress-related biomarkers will be a good approach to manage detrimental effects of PD.

Correlation Between Gamma-Glutamyl Transferase Activity and Glutathione Levels in Molecular Subgroups of Breast Cancer

Objective

The gamma-glutamyl cycle catalyzed by gamma-glutamyl transferase (GGT) plays an important role in glutathione (GSH) homeostasis in the cell. In cells continuously exposed to the drug, the main phase of the enzymatic detoxification is the conjugation of the drug with GSH catalyzed by glutathione-S-transferase (GST). Conjugation of drugs with GSH is the first step in the development of chemotherapeutic drug resistance. In this study, we aimed to investigate the relationship between GGT and GSH in molecular subgroups of breast cancer patients.

Materials and Methods

Serum GGT activity and GSH levels for patients diagnosed with breast cancer (n=58) and healthy controls (n=8) were measured by a spectrophotometric method and a colorimetric kit, respectively.

Results

GGT activity was significantly higher in the total patient group and in the molecular subgroups than those in the control groups (p<0.05). Serum GSH levels were higher in the patient groups compared to controls without reaching statistical significance (p>0.05). GGT activity was positively correlated with GSH levels in the total patients and healthy controls (p<0.001 and p<0.05, respectively). There was also a positive correlation between GGT activity and GSH levels in Luminal A, HER2-positive (Human epidermal growth factor receptor 2), and Triple-negative groups (p<0.05).

Conclusion

This is the first study showing the relationship between GGT and GSH in molecular subgroups of breast cancer. An increase in GGT activity may affect intracellular GSH synthesis. Therefore, having a correlation between GGT and GSH in some molecular subgroups may affect the course of treatment in these patients.

Normal and Tumour Tissue mRNA Expressions of Telomerase Complex Genes in Several Types of Cancer

Aims:

To investigate the changes in mRNA expression levels of telomerase-related significant proteins in several types of cancer.

Methods:

Human telomerase reverse transcriptase, pontin, reptin and dyskerin expressions were measured in normal and tumour tissues obtained from 26 patients with colorectal, breast and gastric cancers, using the real-time reverse transcriptase-polymerase chain reaction method.

Results:

For all patients, no significant difference was found in mRNA expressions of human telomerase reverse transcriptase and dyskerin (p>0.05), although their levels in tumour tissues were found to be higher than in normal tissues. However, pontin and reptin mRNA expressions were significantly higher in tumour tissues than in normal tissues (p<0.01). While human telomerase reverse transcriptase showed a high correlation with only pontin (p<0.001) in normal tissues, high positive correlations were observed between human telomerase reverse transcriptase with pontin (p<0.005), reptin (p<0.01) and dyskerin (p<0.01) in tumour tissues.

Conclusion:

The increased mRNA expressions of all four genes in tumour tissues may suggest a role in cancer development. Correlations of pontin, reptin and dyskerin with human telomerase reverse transcriptase support the hypotheses describing their roles in telomerase complexes.