Cell Line-Specific Direct Irradiation and Bystander Responses are Influenced by Fetal Bovine Serum Serotonin Concentrations

Commonalities in the Features of Cancer and Chronic Fatigue Syndrome (CFS): Evidence for Stress-Induced Phenotype Instability?

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) and Cancer-Related Fatigue (CRF) are syndromes with considerable overlap with respect to symptoms. There have been many studies that have compared the two conditions, and some of this research suggests that the etiologies of the conditions are linked in some cases. In this narrative review, CFS/ME and cancer are introduced, along with their known and putative mechanistic connections to multiple stressors including ionizing radiation. Next, we summarize findings from the literature that suggest the involvement of HPA-axis dysfunction, the serotonergic system, cytokines and inflammation, metabolic insufficiency and mitochondrial dysfunction, and genetic changes in CRF and CFS/ME. We further suspect that the manifestation of fatigue in both diseases and its causes could indicate that CRF and CFS/ME lie on a continuum of potential biological effects which occur in response to stress. The response to this stress likely varies depending on predisposing factors such as genetic background. Finally, future research ideas are suggested with a focus on determining if common biomarkers exist in CFS/ME patients and those afflicted with CRF. Both CFS/ME and CRF are relatively heterogenous syndromes, however, it is our hope that this review assists in future research attempting to elucidate the commonalities between CRF and CFS/ME.

Environmental radiobiology of amphibians - knowledge gaps to be filled using cell lines

Amphibians are facing an unprecedented level of population declines worldwide. The causes run the gamut from habitat loss and succumbing to opportunistic pathogen infections to vulnerability to toxic pollutants and ultraviolet (UV)-B radiation exposure. Anthropogenic activities including Chernobyl and Fukushima nuclear disasters and radioactive waste leakage into the environment raise the background radiation levels. Their immediate and chronic effects on amphibian populations are still being studied. However, the literature on environmental radiation effects on amphibian health still requires a lot more work. Laboratory and field works need to be conducted hand in hand in order to make informative and conclusive analyses to distinguish bad from good and harm from risk or to argue for or against the linear no-threshold model in radioprotection programs. Amphibian cell lines can help seek answers to important questions pertaining environmental radiobiology and amphibian health wherever they can suitably and effectively. The purpose of this work is to show that amphibian cell lines can 'rescue' important knowledge gaps in the literature, especially in the low-dose radiation mechanisms. Presently, there are 142 amphibian cell lines developed from six urodelans and 17 anurans. Amphibian cell lines can help expand and enrich the limited literature on environmental radiation effects on amphibians. They can be used to study mechanisms of radiation actions and discover reliable biomarkers for low-dose exposure. They can be used in environmental radiation monitoring and radioprotection programs. They can be used to determine the effects of co-exposure of IR and other stressors in the environment on amphibian health. They represent an ethical choice for amphibian conservation efforts in the current global amphibian declines. Lessons learned from cellular data can be useful guides to gain a better picture of effects occurring at the amphibian population and ecosystem levels.

External modulators and redox homeostasis: Scenario in radiation-induced bystander cells

Redox homeostasis is imperative to maintain normal physiologic and metabolic functions. Radiotherapy disturbs this balance and induces genomic instability in diseased cells. However, radiation-induced effects propagate beyond the targeted cells, affecting the adjacent non-targeted cells (bystander effects). The cellular impact of radiation, thus, encompasses both targeted and non-targeted effects. Use of external modulators along with radiation can increase radio-therapeutic efficiency. The modulators' classification as protectors or sensitizers depends on interactions with damaged DNA molecules. Thus, it is necessary to realize the functions of various radio-sensitizers or radio-protectors in both irradiated and bystander cells. This review focuses on some modulators of radiation-induced bystander effects (RIBE) and their action mechanisms. Knowledge about the underlying signaling cross-talk may promote selective sensitization of radiation-targeted cells and protection of bystander cells.

Synthesis and biological evaluation of new 3(2H)-pyridazinone derivatives as non-toxic anti-proliferative compounds against human colon carcinoma HCT116 cells

Novel 3(2H)-pyridazinone derivatives were designed, synthesised in satisfactory yields and evaluated in different experimental assays to assess their preliminary toxicity in vivo and anti-proliferative effects against HCT116 cell lines in vitro. Artemia salina lethality test provided LC50 values >100 µg/mL for all compounds. Successive assays revealed that some compounds were endowed with a promising anti-proliferative effect against HCT116 cells, alone or stimulated by serotonin as a pro-inflammatory factor in order to mimick an inflamed model in vivo of cancer cell microenvironment. Moreover, the kinurenic acid level after treatment with these newly synthesised compounds was monitored as a marker of anti-proliferation in colon carcinoma models. The IC50 values obtained for the best-in-class compounds were comparable to that of daunorubicin as a reference drug. Conversely, these compounds were not able to counteract the spontaneous migration of human cancer HCT116 cell line in the wound healing paradigm.

Biopotential of Bersama abyssinica Fresen Stem Bark Extracts: UHPLC Profiles, Antioxidant, Enzyme Inhibitory, and Antiproliferative Propensities

In this study, ethyl acetate, methanol, and water extracts of Bersama abyssinica (Melianthaceae) stem bark were screened for enzyme inhibitory and antioxidant properties. The water extract possessed the highest concentration of phenols (230.83 mg gallic acid equivalent/g extract), while the methanol extract was rich in flavonoids (75.82 mg rutin equivalent/g extract), and the ethyl acetate extract possessed the highest amount of saponins (97.37 mg quillaja equivalent/g). The aim of this study was to investigate the antiproliferative effects against the human colon cancer HCT116 cell line challenged with serotonin (5-HT) as a stimulating-proliferation factor. The level of HCT116 cell-deriving pool of kynurenic acid (KA) was also assessed. The UHPLC results confirmed the presence of 58, 68, and 63 compounds in the ethyl acetate, methanol, and water extracts, respectively. Mangiferin, vitexin and its isomer isovitexin were tentatively identified in all extracts and KA (m/z 190.05042 [M−H]⁺) was also tentatively identified in the methanol and water extracts. The methanol extract (1464.08 mg Trolox equivalent [TE]/g extract) showed the highest activity in the CUPRAC assay, whereas the water extract (1063.70 mg TE/g extract) showed the highest activity with the FRAP technique. The ethyl acetate extract was the most active acetylcholinesterase (4.43 mg galantamine equivalent/g extract) and α-glucosidase (mmol acarbose equivalent /g extract) inhibitor. The water extract was able to inhibit 5-HT-stimulated viability of HCT116 cells, and blunt 5-HT-induced reduction of cell-deriving KA. The scientific data generated in this study provide baseline data regarding the biological properties of B. abyssinica stem bark, highlighting its potential use for the development of new pharmaceutic and cosmetic agents.

5-HT2A and 5-HT3 receptors contribute to the exacerbation of targeted and non-targeted effects of ionizing radiation-induced cell death in human colon carcinoma cells

Purpose: Serotonin (5-HT) is implicated in the underlying mechanisms which mediate cell death following ionizing radiation exposure, however, effects appear to be cell type-dependent. We sought to further characterize the role of 5-HT and 5-HT receptors (5-HTRs) in the exacerbation of cell death following ionizing radiation exposure in human colon carcinoma cells.Materials and methods: We examined the clonogenic survival of colon carcinoma HCT116 cells treated with 5-HT and the selective 5-HTR antagonists ketanserin (5-HT_2A) and ondansetron (5-HT₃), following exposure to direct ionizing radiation and irradiated cell-conditioned medium (ICCM). The relative expression of these target receptors was measured using western blotting.Results: Western blotting results revealed that relative protein levels of the 5-HT_2A and 5-HT₃ receptors were similar. 5-HT concentration-dependent increases in cell death that occurred following direct ionizing radiation exposure were abolished by both 5-HTR antagonists. Death of nonirradiated cells recipient of ICCM was increased in a concentration-dependent manner by 5-HT when present during donor cell irradiation. Both 5-HTR antagonists completely abolished the increases in bystander-induced cell death generated by 5-HT. Finally, we show that exposure of cells to 5-HT prior to receipt of ICCM can also dictate the degree of bystander-induced cell death.Conclusions: Our findings demonstrate a definitive role for 5-HT in the exacerbation of cell death following ionizing radiation exposure in colon carcinoma cells and highlight 5-HTRs as potential markers for predicting cellular radiosensitivity.

Serotonin and 5-HT3 receptors sensitize human skin cells to direct irradiation cell death but not to soluble radiation-induced bystander signals

Ionizing radiation (IR) is an environmental carcinogen and the biological damages it elicits are mechanistically distinct between high and low doses. Non-targeted effects occurring in nonirradiated cells such as the radiation-induced bystander effect predominate at low doses of IR. However, the role of non-targeted effects in environmental radiation protection is often overlooked because the governing mechanisms are complex and multifactorial. An improved understanding of the signaling molecules and their capacity to sensitize specific cell types are essential in establishing environmental IR risks. In particular, serotonin (5-HT) has been identified to exacerbate both direct irradiation and bystander-induced cell death (CD) in certain cell types, although not all cell types are responsive to 5-HT in this respect. In this study, we further characterize the role of 5-HT and 5-HT receptors (5-HTR) in the amplification of CD following IR exposure in human keratinocytes. We examined the survival of HaCaT cells treated with 5-HT and the 5-HTR antagonists ketanserin (5-HT_2A) and ondansetron (5-HT₃) following exposure to direct IR and irradiated cell condition medium (ICCM). Nonirradiated cell survival was consistent with the vehicle control among 5-HT concentrations ranging from 0.001 to 100 μM. Significant 5-HT concentration-dependent increases in CD occurred following direct IR exposure. Nonirradiated ICCM-recipient CD was not altered by 5-HT (0.001-100 μM) when present during donor cell irradiation among all IR doses. Increases in direct irradiation CD evoked by 5-HT were significantly attenuated by ondansetron, blocking the effect of 5-HT, whereas ketanserin did not alter CD. Western blotting of these target 5-HTRs revealed protein expression of the 5-HT₃ receptor, while the 5-HT_2A receptor was not detected. We have demonstrated a definitive role for 5-HT in the exacerbation of CD following direct IR exposure and identified the 5-HT₃ receptor as a potential target for ameliorating radiation damage in keratinocytes.

Relevance of Non-Targeted Effects for Radiotherapy and Diagnostic Radiology; A Historical and Conceptual Analysis of Key Players

Non-targeted effects (NTE) such as bystander effects or genomic instability have been known for many years but their significance for radiotherapy or medical diagnostic radiology are far from clear. Central to the issue are reported differences in the response of normal and tumour tissues to signals from directly irradiated cells. This review will discuss possible mechanisms and implications of these different responses and will then discuss possible new therapeutic avenues suggested by the analysis. Finally, the importance of NTE for diagnostic radiology and nuclear medicine which stems from the dominance of NTE in the low-dose region of the dose–response curve will be presented. Areas such as second cancer induction and microenvironment plasticity will be discussed.

Qualitative Fingerprint Analysis and Multidirectional Assessment of Different Crude Extracts and Essential Oil from Wild Artemisia santonicum L

Artemisia species are used as folk medicines in several countries. This work was aimed to shed more light on the effect of methanol, water, ethyl acetate extracts, and essential oil (EO) of A. santonicum on selected enzymes (cholinesterase, tyrosinase α-amylase, and α-glucosidase) as well of their antioxidant and pharmacological effects. The chemical profile of the essential oil was determined using gas chromatography coupled to mass spectrometry (GC-MS) analysis, while the extracts were chemically characterized by high performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Forty-nine constituents were identified and camphor (36.6%), 1,8-cineole (10.2%), α-thujone (10.1%), borneol (4.5%), and β-thujone (3.6%) were the major components. Overall, 45, 74, and 67 components were identified from the ethyl acetate, methanol, and water extracts, respectively. The EO and extracts showed significant antioxidant properties, in a cell-free model; particularly, methanol and water extracts revealed promising sources of antioxidant compounds. Additionally, we evaluated protective effects of EO and extracts in isolated rat colon tissue challenged with lipopolysaccharide (LPS), as an ex vivo model of colon inflammation, and human colon cancer HCT116 cell line. Particularly, we observed that, among all tested samples, A. santonicum ethyl acetate displayed the best pharmacological profile, being able to blunt LPS-induced levels of all tested biomarkers of inflammation and oxidative stress, including colon nitrites, lactate dehydrogenase, prostaglandin E2, and serotonin. Additionally, this extract was also able to reduce HCT116 cell viability, thus suggesting potential antiproliferative effects against colon cancer cells. Based on our results, A. santonicum has great potential for developing novel functional agents including pharmaceuticals, cosmeceuticals, and nutraceuticals.

An investigation into neutron-induced bystander effects: How low can you go?

Neutron radiation is very harmful to both individual organisms and the environment. A n understanding of all aspects of both direct and indirect effects of radiation is necessary to accurately assess the risk of neutron radiation exposure. This review seeks to review current evidence in the literature for radiation-induced bystander effects and related effects attributable to neutron radiation. It also attempts to determine if the suggested evidence in the literature is sufficient to justify claims that neutron-based radiation can cause radiation-induced bystander effects. Lastly, the present paper suggests potential directions for future research concerning neutron radiation-induced bystander effects. Data was collected from studies investigating radiation-induced bystander effects and was used to mathematically generate pooled datasets and putative trends; this was done to potentially elucidate both the appearance of a conventional trend for radiation-induced bystander effects in studies using different types of radiation. Furthermore, literature review was used to compare studies utilizing similar tissue models to determine if neutron effects follow similar trends as those produced by electromagnetic radiation. We conclude that the current understanding of neutron-attributable radiation-induced bystander effects is incomplete. Various factors such as high gamma contamination during the irradiations, unestablished thresholds for gamma effects, different cell lines, energies, and different dose rates affected our ability to confirm a relationship between neutron irradiation and RIBE, particularly in low-dose regions below 100 mGy. It was determined through meta-analysis of the data that effects attributable to neutrons do seem to exist at higher doses, while gamma effects seem likely predominant at lower dose regions. Therefore, whether neutrons can induce bystander effects at lower doses remains unclear. Further research is required to confirm these findings and various recommendations are made to assist in this effort. With these recommendations, we hope that research conducted in the future will be better equipped to explore the indirect effects of neutron radiation as they pertain to biological and ecological phenomena.