Regulatory T cells: Their role in triple-negative breast cancer progression and metastasis.

Triple-negative breast cancer (TNBC) is an aggressive and immunogenic subtype of breast cancer. This tumorigenicity is independent of hormonal or HER2 pathways because of a lack of respective receptor expression. TNBC is extremely prone to drug resistance and early recurrence because of T-regulatory cell (Treg) infiltration into the tumor microenvironment (TME) in addition to other mechanisms like genomic instability. Tumor-infiltrating Tregs interact with both tumor and stromal cells as well as extracellular matrix components in the TME and induce an immune-suppressive phenotype. Hence, treatment of TNBC with conventional therapies remains challenging. Understanding the protective mechanism of Tregs in shielding TNBC from antitumor immune responses in the TME will pave the way for developing novel, immune-based therapeutics. The current review focuses on the role of tumor-infiltrating Tregs in tumor progression and metabolic reprogramming of the TME. The authors have extended their focus to oncotargeting Treg-mediated immune suppression in breast cancer. Because of its potential role in the TME, modulating Treg activity may provide a novel strategic intervention to combat TNBC. Both under laboratory conditions and in clinical trials, currently available anticancer drugs and natural therapeutics as potential agents for targeting Tregs are explored.

In vitro evidence that an aqueous extract of Centella asiatica modulates α-synuclein aggregation dynamics.

α-Synuclein aggregation is one of the major etiological factors implicated in Parkinson's disease (PD). The prevention of aggregation of α-synuclein is a potential therapeutic intervention for preventing PD. The discovery of natural products as alternative drugs to treat PD and related disorders is a current trend. The aqueous extract of Centella asiatica (CA) is traditionally used as a brain tonic and CA is known to improve cognition and memory. There are limited data on the role of CA in modulating amyloid-ß (Aß) levels in the brain and in Aß aggregation. Our study focuses on CA as a modulator of the α-synuclein aggregation pattern in vitro. Our investigation is focused on: (i) whether the CA leaf aqueous extract prevents the formation of aggregates from monomers (Phase I: α-synuclein + extract co-incubation); (ii) whether the CA aqueous extract prevents the formation of fibrils from oligomers (Phase II: extract added after oligomers formation); and (iii) whether the CA aqueous extract disintegrates the pre-formed fibrils (Phase III: extract added to mature fibrils and incubated for 9 days). The aggregation kinetics are studied using a thioflavin-T assay, circular dichroism, and transmission electron microscopy. The results showed that the CA aqueous extract completely inhibited the α-synuclein aggregation from monomers. Further, CA extract significantly inhibited the formation of oligomer to aggregates and favored the disintegration of the preformed fibrils. The study provides an insight in finding new natural products for future PD therapeutics.

Protection of DNA and erythrocytes from free radical induced oxidative damage by black gram (Vigna mungo L.) husk extract.

Antioxidants present in various plant tissues exhibit health benefits by scavenging reactive oxygen species generated under various pathophysiological conditions. In the present study, bioactive compounds from black gram husk were extracted with water and the protection of black gram husk (BGH) extract against oxidative damage in DNA and erythrocytes were studied. BGH extract had total polyphenol content of 59 mg of gallic acid equivalents (GAE). The phenolic acids identified in the extract using RP-HPLC were gallic, protocatechuic, gentisic and ferulic acids. The extract showed good antioxidant properties. The IC(50) value for DPPH radical scavenging activity was found to be 3.92 µg of GAE. The BGH extract also showed α-glucosidase inhibition and the IC(50) value was found to be 2.78 µg of GAE. The oxidative hemolysis caused by hydrogen peroxide in rat erythrocytes was inhibited by BGH extract in a dose dependent manner. The IC(50) values for BGH extract and BHA for hemolysis were 11.5 and 14 µg of GAE, respectively. Morphological changes in erythrocyte membrane caused by hydrogen peroxide were protected by BGH extract. As BGH extract exhibited various antioxidant properties in different systems, it could be used as a functional food or nutraceutical product for health benefits.

DNA induced folding/fibrillation of alpha-synuclein: new insights in Parkinson's disease.

Emerging evidences on the nuclear localization of alpha-Synuclein in neurons and a close look in to its primary sequence/structural organization led us to examine its DNA binding ability. Subsequently, we first time demonstrated the interaction of DNA with alpha-Synuclein which was also confirmed by others. We recently showed that double-stranded oligos induce partial folding in alpha-Synuclein and promote its aggregation, where as single-strand circular DNA and supercoiled plasmid DNA induced a helix-rich conformation and protected the protein from fibrillation. In turn, alpha-Synuclein modulates DNA conformation from B- to an altered B-form, which may affect DNA transactions. Interestingly, amyloid-beta peptides and prion proteins implicated in Alzheimer's disease and Prion diseases respectively, were also shown to have DNA binding activity which suggests that DNA binding may be a common property of many amyloidogenic proteins associated with various neurodegenerative disorders. In this review, we debate the biological significance of DNA-alpha-Synuclein interactions; it's beneficial vs. toxic role in relevance to Parkinson's disease.