An in vitro investigation into the protective and genotoxic effects of myricetin bulk and nano forms in lymphocytes of MGUS patients and healthy individuals

Assessment of the cytostasis and chromosomal instability potential of myricetin and its chemopreventive effect against bleomycin-induced cyto-genotoxicity

Myricetin (ME) is a major constituent of various foods and beverages consumed by humans, including vegetables, teas and fruits, and is primarily recognized for its iron-chelating, antioxidant, anti-inflammatory and anti-cancer properties. This study evaluated the cytostatic, genotoxic, and chemopreventive effects of ME in CHO-K1 cells using the Cytokinesis-Block Micronucleus (CBMN) assay and explored molecular interactions through in silico systems biology analysis. CHO-K1 cells were exposed to ME (2.5-40 µM). Cytostasis was assessed by the Cytokinesis-Block Proliferation Index (CBPI), and chromosomal instability was measured by the frequency of micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs). ME at 40 µM significantly reduced CBPI, while concentrations of 20 and 40 µM increased chromosomal instability (p < 0.05). For chemoprevention, ME (2.5-10 µM) was administered in pre-, co-, and post-treatment with bleomycin (BLM). ME significantly reduced BLM-induced MNi and NPBs in all protocols (p < 0.05). In silico analysis revealed strong interactions between ME and key proteins related to DNA damage response, apoptosis, and bleomycin detoxification. Notably, the in silico analysis revealed a strong association between ME and bleomycin hydrolase (BLMH) and the interaction of ME with proteins related to DNA damage response and apoptosis regulation. Overall, ME exhibited genotoxicity at high concentrations but demonstrated a significant chemopreventive effect at lower, nontoxic doses. These findings provide insights into the dual biological activity of ME and support its potential use as a protective agent against genotoxic damage.

Bioinspired synthesis of protein/polysaccharide-decorated folate as a nanocarrier of curcumin to potentiate cancer therapy

Curcumin is a promising anticancer agent, but its clinical utilization has been hindered by its low solubility and bioaccessibility. To overcome these obstacles, we developed a natural protein-polysaccharide nanocomplex made from casein nanoparticles coated with a double layer of alginate and chitosan and decorated with folic acid (fCs-Alg@CCasNPs) for use as a nanocarrier for curcumin. The developed nanoformulation showed a drug encapsulation efficiency = 75%. The measured size distribution of fCs-Alg@CCasNPs was 333.8 ± 62.35 nm with a polydispersity index (PDI) value of 0.179. The recorded zeta potential value of fCs-Alg@CCasNPs was 28.5 mV. Morphologically, fCs-Alg@CCasNPs appeared spherical, as shown by transmission electron microscopy (TEM). The successful preparation of fCs-Alg@CCasNPs was confirmed by Fourier transform infrared (FTIR) spectroscopy of all the constituents forming the nanoformulation. Further in vitro investigations indicated the stability of fCs-Alg@CCasNPs as well as their controlled and sustained release of curcumin in the tumor microenvironment. Compared with free curcumin, fCs-Alg@CCasNPs induced a higher cytotoxic effect against a pancreatic cancer cell line. The in vivo pharmacokinetics of fCs-Alg@CCasNPs showed a significant AUC_0-24 = 2307 ng.h/ml compared to 461 ng.h/ml of free curcumin; these results indicated high curcumin bioavailability in plasma. The in vivo results of tumor weight, the amount of DNA damage measured by comet assay and histopathological examination revealed that treating mice with fCs-Alg@CCasNPs (either intratumorally or intraperitonially) prompted higher therapeutic efficacy against Ehrlich carcinoma than treatment with free curcumin. Therefore, the incorporation of curcumin with protein/polysaccharide/folate is an innovative approach that can synergistically enhance curcumin bioavailability and potentiate cancer therapy with considerable biosafety.

Ex vivo/in vitro effects of aspirin and ibuprofen, bulk and nano forms, in peripheral lymphocytes of prostate cancer patients and healthy individuals

Inhibiting inflammatory processes or eliminating inflammation represents a logical role in the suppression and treatment strategy of cancer. Several studies have shown that anti-inflammatory drugs (NSAIDs) act as anticancer agents while reducing metastases and mortality rate. NSAIDs are seriously limited by their side effects and toxicity, which can become cumulative with their long-term administration for chemoprevention. In the current ex vivo / in vitro study, the genotoxicity mechanisms of NSAIDS in bulk and nanoparticle forms allowed a strategy to prevent and minimise the damage in human lymphocytes. When compared to their bulk forms, acetylsalicylic acid (Aspirin) nano and ibuprofen nano (IBU N), both NSAIDs in 500 μg/mL concentration significantly decreased DNA damage measured by alkaline comet assay. Micronuclei (MNi) frequency also decreased after ASP N (500 μg/mL), ASP B (500 μg/mL) and IBU N (200 μg/mL) in prostate cancer patients and healthy individuals, however, the ibuprofen bulk (200 μg/mL) showed a significant increase in MNi formation in lymphocytes from healthy and prostate cancer patients when compared to the respective untreated lymphocytes. These findings suggest that a reduction in particle size had an impact on the reactivity of the drug, further emphasising the potential of nanoparticles to improve the current treatment options.

Anticancer potential of myricetin bulk and nano forms in vitro in lymphocytes from myeloma patients

Evading apoptosis and chemo-resistance are considered as very important factors which help tumour progression and metastasis. Hence, to overcome chemo-resistance, there is an urgent requirement for emergence of more effective treatment options. Myricetin, a naturally occurring flavonoid, is present in various plant-derived foods and shows antitumour potential in different cancers. In the present in vitro study, results from the comet assay demonstrated that myricetin bulk (10 µM) and nano (20 µM) forms exhibited a non-significant level of genotoxicity in lymphocytes from multiple myeloma patients when compared to those from healthy individuals. Western blot results showed a decrease in Bcl-2/Bax ratio and an increase in P53 protein levels in lymphocytes from myeloma patients, but not in lymphocytes from healthy individuals. A significant increase in intracellular reactive oxygen species level was also observed, suggesting that regulation of apoptotic proteins triggered by myricetin exposure in lymphocytes from myeloma patients occurred through P53 and oxidative stress-dependent pathways. The potency of myricetin against lymphocytes from myeloma patients marks it a potential candidate to be considered as an alternative to overcome chemo-resistance in cancer therapies.

Recent applications of the Comet Assay: A report from the International Comet Assay Workshop 2019

The International Comet Assay Workshops (ICAW) are a series of scientific conferences dealing with different aspects of the comet assay. The assay itself is a simple method for the detection of DNA strand breaks at the cellular level and can be applied to any cell type derived from different organs and tissues of eukaryotic organisms. Additionally, the comet assay is widely applied in human biomonitoring, ecotoxicology, genotoxicity testing of chemicals, but also in basic research studying the mechanisms of DNA damage and repair. The 2019 ICAW edition gathered about 80 participants with over 30 lecturers, 27 poster presentations and 2 open discussion sessions presenting the latest advances in technical developments as well as applications of the comet assay in genetic toxicology, and environmental and human biomonitoring. This report summarises the important issues that were raised and discussed during the sessions as well as a short synopsis of the papers selected for inclusion in this special issue. Based on the topics presented at the workshop, the assay with its new modifications and applications has a bright future and will for sure stay one of the most popular methods in genetic toxicology and beyond in the years to come.