Simvastatin treatment varies the radiation response of human breast cells in 2D or 3D culture.

Background Statins inhibit the cholesterol biosynthesis and are used as cholesterol-lowering agents in fat-metabolism disorders. Furthermore, several studies state that statins have supportive functions in breast cancer treatment. Therefore, simvastatin (SVA) as a potential radiosensitizer should be investigated on the basis of human breast cells. Methods First, an optimal concentration of SVA for normal (MCF10A) and cancer (MCF-7) cells was identified via growth and cytotoxicity assays that, according to the definition of a radiosensitizer in the narrower sense, enhances the effect of radiation therapy but has no cytotoxic effect. Next, in combination with radiation SVA's influence on DNA repair capacity and clonogenic survival in 2D and 3D was determined. Furthermore cell cycle distribution, expression of survivin and connective tissue growth factor (CTGF) as well as ERK1 map kinase were analysed. Results 1 µM SVA was identified as highest concentration without an influence on cell growth and cytotoxicity and was used for further analyses. In terms of early and residual γH2AX-foci, SVA affected the number of foci in both cell lines with or without irradiation. Different radiation responses were detected in 2D and 3D culture conditions. During the 2D cultivation, a radiosensitizing effect within the clonogenic survival was observable, but not in 3D. Conclusion The present study suggests that SVA may have potential for radiosensitization. Therefore, it is important to further investigate the role of SVA in relation to the extent of radiosensitization and how it could be used to positively influence the therapy of breast cancer or other entities.

Genetically Encoded Photosensitizer for Destruction of Protein or Cell Function.

There are several paths when excited molecules return to the ground state. In the case of fluorescent molecules, the dominant path is fluorescence emission that is greatly contributing to bioimaging. Meanwhile, photosensitizers transfer electron or energy from chromophore to the surrounding molecules, including molecular oxygen. Generated reactive oxygen species has potency to attack other molecules by oxidation. In this chapter, we introduce the chromophore-assisted light inactivation (CALI) method using a photosensitizer to inactivate proteins in a spatiotemporal manner and development of CALI tools, which is useful for investigation of protein functions and dynamics, by inactivation of the target molecules. Moreover, photosensitizers with high efficiency make it possible optogenetic control of cell ablation in living organisms and photodynamic therapy. Further development of photosensitizers with different excitation wavelengths will contribute to the investigation of multiple proteins or cell functions through inactivation in the different positions and timings.

Optochemical Control of Biological Processes in Cells and Animals.

Biological processes are naturally regulated with high spatial and temporal control, as is perhaps most evident in metazoan embryogenesis. Chemical tools have been extensively utilized in cell and developmental biology to investigate cellular processes, and conditional control methods have expanded applications of these technologies toward resolving complex biological questions. Light represents an excellent external trigger since it can be controlled with very high spatial and temporal precision. To this end, several optically regulated tools have been developed and applied to living systems. In this review we discuss recent developments of optochemical tools, including small molecules, peptides, proteins, and nucleic acids that can be irreversibly or reversibly controlled through light irradiation, with a focus on applications in cells and animals.

Manipulation of cells with laser microbeam scissors and optical tweezers: a review.

The use of laser microbeams and optical tweezers in a wide field of biological applications from genomic to immunology is discussed. Microperforation is used to introduce a well-defined amount of molecules into cells for genetic engineering and optical imaging. The microwelding of two cells induced by a laser microbeam combines their genetic outfit. Microdissection allows specific regions of genomes to be isolated from a whole set of chromosomes. Handling the cells with optical tweezers supports investigation on the attack of immune systems against diseased or cancerous cells. With the help of laser microbeams, heart infarction can be simulated, and optical tweezers support studies on the heartbeat. Finally, laser microbeams are used to induce DNA damage in living cells for studies on cancer and ageing.

Effects of the pulsed electromagnetic field PST® on human tendon stem cells: a controlled laboratory study.

BACKGROUND: Current clinical procedures for rotator cuff tears need to be improved, as a high rate of failure is still observed. Therefore, new approaches have been attempted to stimulate self-regeneration, including biophysical stimulation modalities, such as low-frequency pulsed electromagnetic fields, which are alternative and non-invasive methods that seem to produce satisfying therapeutic effects. While little is known about their mechanism of action, it has been speculated that they may act on resident stem cells. Thus, the purpose of this study was to evaluate the effects of a pulsed electromagnetic field (PST®) on human tendon stem cells (hTSCs) in order to elucidate the possible mechanism of the observed therapeutic effects. METHODS: hTSCs from the rotator cuff were isolated from tendon biopsies and cultured in vitro. Then, cells were exposed to a 1-h PST® treatment and compared to control untreated cells in terms of cell morphology, proliferation, viability, migration, and stem cell marker expression. RESULTS: Exposure of hTSCs to PST® did not cause any significant changes in proliferation, viability, migration, and morphology. Instead, while stem cell marker expression significantly decreased in control cells during cell culturing, PST®-treated cells did not have a significant reduction of the same markers. CONCLUSIONS: While PST® did not have significant effects on hTSCs proliferation, the treatment had beneficial effects on stem cell marker expression, as treated cells maintained a higher expression of these markers during culturing. These results support the notion that PST® treatment may increase the patient stem cell regenerative potential.

Exposure to 3G mobile phone signals does not affect the biological features of brain tumor cells.

BACKGROUND: The increase in mobile phone use has generated concerns about possible risks to human health, especially the development of brain tumors. Whether tumor patients should continue to use mobile telephones has remained unclear because of a paucity of information. Herein, we investigated whether electromagnetic fields from mobile phones could alter the biological features of human tumor cells and act as a tumor-promoting agent. METHODS: Human glioblastoma cell lines, U251-MG and U87-MG, were exposed to 1950-MHz time division-synchronous code division multiple access (TD-SCDMA) at a specific absorption rate (maximum SAR = 5.0 W/kg) for 12, 24, and 48 h. Cell morphologies and ultra-structures were observed by microscopy and the rates of apoptosis and cell cycle progression were monitored by flow cytometry. Additionally, cell growth was determined using the CKK-8 assay, and the expression levels of tumor and apoptosis-related genes and proteins were analyzed by real-time PCR and western blotting, respectively. Tumor formation and invasiveness were measured using a tumorigenicity assay in vivo and migration assays in vitro. RESULTS: No significant differences in either biological features or tumor formation ability were observed between unexposed and exposed glioblastoma cells. Our data showed that exposure to 1950-MHz TD-SCDMA electromagnetic fields for up to 48 h did not act as a cytotoxic or tumor-promoting agent to affect the proliferation or gene expression profile of glioblastoma cells. CONCLUSIONS: Our findings implied that exposing brain tumor cells in vitro for up to 48 h to 1950-MHz continuous TD-SCDMA electromagnetic fields did not elicit a general cell stress response.

Dose and dose-rate effects of ionizing radiation: a discussion in the light of radiological protection.

The biological effects on humans of low-dose and low-dose-rate exposures to ionizing radiation have always been of major interest. The most recent concept as suggested by the International Commission on Radiological Protection (ICRP) is to extrapolate existing epidemiological data at high doses and dose rates down to low doses and low dose rates relevant to radiological protection, using the so-called dose and dose-rate effectiveness factor (DDREF). The present paper summarizes what was presented and discussed by experts from ICRP and Japan at a dedicated workshop on this topic held in May 2015 in Kyoto, Japan. This paper describes the historical development of the DDREF concept in light of emerging scientific evidence on dose and dose-rate effects, summarizes the conclusions recently drawn by a number of international organizations (e.g., BEIR VII, ICRP, SSK, UNSCEAR, and WHO), mentions current scientific efforts to obtain more data on low-dose and low-dose-rate effects at molecular, cellular, animal and human levels, and discusses future options that could be useful to improve and optimize the DDREF concept for the purpose of radiological protection.

[Life Span of F1 Progeny of Female Drosophila Exposed to Low Intensity Terahertz Irradiation].

Virgin female fruit flies were stressed by placement into a confined space without food for 3 hours. Some flies were subjected to terahertz irradiation (0,1-2,2 THz) for the last 30 min. Irradiated and nonirradiated females were then copulated with males. We investigated the F1 progeny of fruit flies with mature and immature oocytes at the moment of irradiation (days of oviposition: 1-2 and 9-10 after irradiation). Life span of individual flies was evaluated. It was demonstrated that terahertz radiation does not influence the absolute and average lifespan of the F1 progeny in both sexes. In response to terahertz irradiation the sexual dimorphism was detected. Survival curves of males, developed from mature and immature oocytes at the time of irradiation, differ significantly from the appropriate control, whereas in the case of females the survival curves are similar to the control. It is concluded that terahertz radiation has a remote effect on a survival of the F1 male progeny.

Effects of low-intensity pulsed ultrasound on cell viability, proliferation and neural differentiation of induced pluripotent stem cells-derived neural crest stem cells.

Low-intensity pulsed ultrasound (LIPUS) acting on induced pluripotent stem cells-derived neural crest stem cells (iPSCs-NCSCs) is considered a promising therapy to improve the efficacy of injured peripheral nerve regeneration. Effects of LIPUS on cell viability, proliferation and neural differentiation of iPSCs-NCSCs were examined respectively in this study. LIPUS at 500 mW cm(-2) enhanced the viability and proliferation of iPSCs-NCSCs after 2 days and, after 4 days, up-regulated gene and protein expressions of NF-M, Tuj1, S100ß and GFAP in iPSCs-NCSCs whereas after 7 days expression of only NF-M, S100ß and GFAP were up-regulated. LIPUS treatment at an appropriate intensity can, therefore, be an efficient and cost-effective method to enhance cell viability, proliferation and neural differentiation of iPSCs-NCSCs in vitro for peripheral nerve tissue engineering.

[Heat shock proteins: aging changes, development thrombotic diseases and peptidergic regulation of genes].

The review and the data of our own investigation demonstrated the role of heat shock proteins in regulation of intracellular and tissue homeostasis at stress influence. The review told that decrease of expression of heat shock proteins can be one of the main causes of aging. Heat shock proteins, which are regulators of proliferation, apoptosis, differentiation of cells and intracellular homeostasis, play important role in activity of immune, cardiovascular and other systems and take part in development of atherosclerosis, heart attack, ischemic stroke and other thrombotic diseases. One of the ways to repair the expression of heat shock proteins is using short peptides.

[Low efficiency of repair of critical DNA damage induced by low doses of radiation].

This study provides an analysis of the development of cellular response to the critical DNA damage and the mechanisms for limiting the efficiency of repairing such damages induced by low doses of ionizing radiation exposure. Based on the data of many studies, one can conclude that the majority of damages occurring in the DNA of the cells after exposure to ionizing radiation significantly differ in their chemical nature from the endogenous ones. The most important characteristic of radiation-induced DNA damages is their complexity and clustering. Double strand breaks, interstrand crosslinks or destruction of the replication fork and formation of long single-stranded gaps in DNA are considered to be critical damages for the fate of cells. The occurrence of such lesions in DNA may be a key event in the etiology and the therapy of cancer. The appearance in the cells of the critical DNA damage induces a rapid development of a complex and ramified network of molecular and biochemical reactions which are called the cellular response to DNA damage. Induction of the cellular response to DNA damage involves the activation of the systems of cell cycle checkpoints, DNA repair, changes in the expression of many genes, reconstruction of the chromatin or apoptosis. However, the efficiency of repair of the complex DNA damage in cells after exposure to low doses of radiation remains at low levels. The development of the cell response to DNA damages after exposure to low doses of radiation does not reach the desired result due to a small amount of damage, with the progression of the phase cell cycle being ahead of the processes of DNA repair. This is primarily due to the failure of signalization to activate the checkpoint of the cell cycle for its arrest in the case of a small number of critical DNA lesions. In the absence of the arrest of the phase cell cycle progression, especially during the G2/M transition, the reparation mechanisms fail to completely restore DNA, and cells pass into mitosis with a damaged DNA. It is assumed that another reason for the low efficiency of DNA repair in the cells after exposure to low doses of radiation is the existence of a restricted access for the repair system components to the complex damages at the DNA sites of highly compacted chromatin.

Bioelectric effects of intense ultrashort pulses.

Models for electric field interactions with biological cells predict that pulses with durations shorter than the charging time of the outer membrane can affect intracellular structures. Experimental studies in which human cells were exposed to pulsed electric fields of up to 300 kV/cm amplitude, with durations as short as 10 ns, have confirmed this hypothesis. The observed effects include the breaching of intracellular granule membranes without permanent damage to the cell membrane, abrupt rises in intracellular free calcium levels, enhanced expression of genes, cytochrome c release, and electroporation for gene transfer and drug delivery. At increased electric fields, the application of nanosecond pulses induces apoptosis (programmed cell death) in biological cells, an effect that has been shown to reduce the growth of tumors. Possible applications of the intracellular electroeffects are enhancing gene delivery to the nucleus, controlling cell functions that depend on calcium release (causing cell immobilization), and treating tumors. Such nanosecond electrical pulses have been shown to successfully treat melanoma tumors by using needle arrays as pulse delivery systems. Reducing the pulse duration of intense electric field pulses even further into the subnanosecond range will allow for the use of wideband antennas to deliver the electromagnetic fields into tissue with a spatial resolution in the centimeter range. This review carefully examines the above concepts, provides a theoretical basis, and modeling results based on both continuum approaches and atomistic molecular dynamics methods. Relevant experimental data are also presented, and some of the many potential bioengineering applications discussed.

Recent insights into the biological action of heavy-ion radiation.

Biological effectiveness varies with the linear energy transfer (LET) of ionizing radiation. During cancer therapy or long-term interplanetary manned explorations, humans are exposed to high-LET energetic heavy ions that inactivate cells more effectively than low-LET photons like X-rays and gamma-rays. Recent biological studies have illustrated that heavy ions overcome tumor radioresistance caused by Bcl-2 overexpression, p53 mutations and intratumor hypoxia, and possess antiangiogenic and antimetastatic potential. Compared with heavy ions alone, the combination with chemical agents (a Bcl-2 inhibitor HA14-1, an anticancer drug docetaxel, and a halogenated pyrimidine analogue 5-iodo-2'-deoxyuridine) or hyperthermia further enhances tumor cell killing. Beer, its certain constituents, or melatonin ameliorate heavy ion-induced damage to normal cells. In addition to effects in cells directly targeted with heavy ions, there is mounting evidence for nontargeted biological effects in cells that have not themselves been directly irradiated. The bystander effect of heavy ions manifests itself as the loss of clonogenic potential, a transient apoptotic response, delayed p53 phosphorylation, alterations in gene expression profiles, and the elevated frequency of gene mutations, micronuclei and chromosome aberrations, which arise in nonirradiated cells having received signals from irradiated cells. Proposed mediating mechanisms involve gap junctional intercellular communication, reactive oxygen species and nitric oxide. This paper reviews briefly the current knowledge of the biological effects of heavy-ion irradiation with a focus on recent findings regarding its potential benefits for therapeutic use as well as on the bystander effect.

Molecular mechanisms involved in adaptive responses to radiation, UV light, and heat.

Viable organisms recognize and respond to environmental changes or stresses. When these environmental changes and their responses by organisms are extreme, they can limit viability. However, organisms can adapt to these different stresses by utilizing different possible responses via signal transduction pathways when the stress is not lethal. In particular, prior mild stresses can provide some aid to prepare organisms for subsequent more severe stresses. These adjustments or adaptations for future stresses have been called adaptive responses. These responses are present in bacteria, plants and animals. The following review covers recent research which can help describe or postulate possible mechanisms which may be active in producing adaptive responses to radiation, ultraviolet light, and heat.

Applications of particle microbeams in space radiation research.

Galactic cosmic radiation is acknowledged as one of the major barriers to human space exploration. In space, astronauts are exposed to charged particles from Z = 1 (H) up to Z = 28 (Ni), but the probability of a hit to a specific single cell in the human body is low. Particle microbeams can deliver single charged particles of different charge and energy to single cells from different tissues, and microbeam studies are therefore very useful for improving current risk estimates for long-term space travel. 2D in vitro cell cultures can be very useful for establishing basic molecular mechanisms, but they are not sufficient to extrapolate risk, given the substantial evidence proving tissue effects are key in determining the response to radiation insult. 3D tissue or animal systems represent a more promising target for space radiobiology using microbeams.

Monte Carlo dosimetry for targeted irradiation of individual cells using a microbeam facility.

Microbeam facilities provide a unique opportunity to investigate the effects of ionising radiation on living biological cells with a precise control of the delivered dose. This paper describes dosimetry calculations performed at the single-cell level in the microbeam irradiation facility available at the Centre d'Etudes Nucléaires de Bordeaux-Gradignan in France, using the object-oriented Geant4 Monte Carlo simulation toolkit. The cell geometry model is based on high-resolution three-dimensional voxelised phantoms of a human keratinocyte (HaCaT) cell line. Such phantoms are built from confocal microscopy imaging and from ion beam chemical elemental analysis. Results are presented for single-cell irradiation with 3 MeV incident alpha particles.

A brief review of radiation hormesis.

This paper reviews physical, experimental and epidemiological evidence for and against radiation hormesis and discusses implications with regards to radiation protection. The scientific community is still divided on the premise of radiation hormesis, with new literature published on a regular basis. The International Commission on Radiological Protection (ICRP) recommends the use of the Linear No Threshold (LNT) model, for planning radiation protection. This model states that the probability of induced cancer and hereditary effects increases with dose in a linear fashion. As a consequence, all radiation exposures must be justified and have a sufficient protection standard in place so that exposures are kept below certain dose limitations. The LNT model has sufficient evidence at high doses but has been extrapolated in a linear fashion to low dose regions with much less scientific evidence. Much experimentation has suggested discrepancies of this extrapolation at low doses. The hypothesis of radiation hormesis suggests low dose radiation is beneficial to the irradiated cell and organism. There is definite standing ground for the hormesis hypothesis both evolutionarily and biophysically, but experimental evidence is yet to change official policies on this matter. Application of the LNT model has important radiation protection and general human health ramifications, and thus it is important that the matter be resolved.

PROSPECTS FOR METROLOGY RELATED TO BIOLOGICAL RADIATION EFFECTS OF ION BEAMS.

In recent years, several approaches have been proposed to provide an understanding of the enhanced relative biological effectiveness of ion beams based on multi-scale models of their radiation effects. Among these, the BioQuaRT project was the only one which focused on developing metrology for a multi-scale characterization of particle track structure. The progress made within the BioQuaRT project has motivated the formation of a department 'Radiation Effects' at PTB dedicated to metrological research on ionizing radiation effects. This paper gives an overview of the department's present research directions and shortly discusses ideas for the future development of metrology related to biological effects of ion beams that are based on a stakeholder consultation.

Precise cell behaviors manipulation through light-responsive nano-regulators: recent advance and perspective.

Nanotechnology-assisted spatiotemporal manipulation of biological events holds great promise in advancing the practice of precision medicine in healthcare systems. The progress in internal and/or external stimuli-responsive nanoplatforms for highly specific cellular regulations and theranostic controls offer potential clinical translations of the revolutionized nanomedicine. To successfully implement this new paradigm, the emerging light-responsive nanoregulators with unparalleled precise cell functions manipulation have gained intensive attention, providing UV-Vis light-triggered photocleavage or photoisomerization studies, as well as near-infrared (NIR) light-mediated deep-tissue applications for stimulating cellular signal cascades and treatment of mortal diseases. This review discusses current developments of light-activatable nanoplatforms for modulations of various cellular events including neuromodulations, stem cell monitoring, immunomanipulation, cancer therapy, and other biological target intervention. In summary, the propagation of light-controlled nanomedicine would place a bright prospect for future medicine.

Enhanced Antitumor Efficacy Achieved Through Combination of nsPEFs and Low-Dosage Paclitaxel.

Looking for a safe and effective cancer therapy for patients is becoming an important and promising research direction. Nanosecond pulsed electric field (nsPEF) has been found to be a potential non-thermal therapeutic technique with few side effects in pre-clinical studies. On the other hand, paclitaxel (PTX), as a common chemotherapeutic agent, shows full anti-tumor activities and is used to treat a wide variety of cancers. However, the delivery of PTX is challenging due to its poor aqueous solubility. Hence, high dosages of PTX have been used to achieve effective treatment, which creates some side effects. In this study, nsPEF was combined with low-level PTX, in order to validate if this combined treatment could bring about enhanced efficacy and allow reduced doses of PTX in clinical application. Cell proliferation, apoptosis, and cell cycle distribution were examined using MTT and flow cytometry assay, respectively. Results showed that combination treatments of nsPEF and PTX exhibited significant synergistic effects in vitro. The underlying mechanism might be that these two agents acted at different targets and coordinately enhanced MDA-MB-231 cell death.