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Oncotarget Mar 2016Radiation therapy (RT) is one of the most important strategies in cancer treatment. Radioresistance (the failure to RT) results in locoregional recurrence and... (Review)
Review
Radiation therapy (RT) is one of the most important strategies in cancer treatment. Radioresistance (the failure to RT) results in locoregional recurrence and metastasis. Therefore, it is critically important to investigate the mechanisms leading to cancer radioresistance to overcome this problem and increase patients' survival. Currently, the majority of the radioresistance-associated researches have focused on preclinical studies. Although the exact mechanisms of cancer radioresistance have not been fully uncovered, accumulating evidence supports that cancer stem cells (CSCs) and different signaling pathways play important roles in regulating radiation response and radioresistance. Therefore, targeting CSCs or signaling pathway proteins may hold promise for developing novel combination modalities and overcoming radioresistance. The present review focuses on the key evidence of CSC markers and several important signaling pathways in cancer radioresistance and explores innovative approaches for future radiation treatment.
Topics: Animals; Humans; Neoplasms; Neoplastic Stem Cells; Radiation Tolerance; Signal Transduction
PubMed: 26716904
DOI: 10.18632/oncotarget.6760 -
Small (Weinheim An Der Bergstrasse,... Jan 2023Carbon nanotube (CNT) field-effect transistors (FETs) have been considered ideal building blocks for radiation-hard integrated circuits (ICs), the demand for which is...
Carbon nanotube (CNT) field-effect transistors (FETs) have been considered ideal building blocks for radiation-hard integrated circuits (ICs), the demand for which is exponentially growing, especially in outer space exploration and the nuclear industry. Many studies on the radiation tolerance of CNT-based electronics have focused on the total ionizing dose (TID) effect, while few works have considered the single event effects (SEEs) and displacement damage (DD) effect, which are more difficult to measure but may be more important in practical applications. Measurements of the SEEs and DD effect of CNT FETs and ICs are first executed and then presented a comprehensive radiation effect analysis of CNT electronics. The CNT ICs without special irradiation reinforcement technology exhibit a comprehensive radiation tolerance, including a 1 × 10 MeVcm mg level of the laser-equivalent threshold linear energy transfer (LET) for SEEs, 2.8 × 10 MeV g for DD and 2 Mrad (Si) for TID, which are at least four times higher than those in conventional radiation-hardened ICs. The ultrahigh intrinsic comprehensive radiation tolerance will promote the applications of CNT ICs in high-energy solar and cosmic radiation environments.
Topics: Transistors, Electronic; Nanotubes, Carbon; Radiation Tolerance
PubMed: 36366937
DOI: 10.1002/smll.202204537 -
Cancer Radiotherapie : Journal de La... Oct 2020From surviving fraction to tumour curability, definitions of tumour radioresistance may vary depending on the view angle. Yet, mechanisms of radioresistance have been... (Review)
Review
From surviving fraction to tumour curability, definitions of tumour radioresistance may vary depending on the view angle. Yet, mechanisms of radioresistance have been identified and involve tumour-specific oncogenic signalling pathways, tumour metabolism and proliferation, tumour microenvironment/hypoxia, genomics. Correlations between tumour biology (histology) and imaging allow theragnostic approaches that use non-invasive biological imaging using tracer functionalization of tumour pathway biomarkers, imaging of hypoxia, etc. Modelling dose prescription function based on their tumour radio-resistant factor enhancement ratio, related to metabolism, proliferation, hypoxia is an area of investigation. Yet, the delivery of dose painting by numbers/voxel-based radiotherapy with low lineal energy transfer particles may be limited by the degree of modulation complexity needed to achieve the doses needed to counteract radioresistance. Higher lineal energy transfer particles or combinations of different particles, or combinations with drugs and devices such as done with radioenhancing nanoparticles may be promising.
Topics: Brain Neoplasms; Humans; Radiation Tolerance; Radiotherapy, Intensity-Modulated
PubMed: 32753241
DOI: 10.1016/j.canrad.2020.05.005 -
FEMS Microbiology Letters Oct 2021Metarhizium is an important genus of soil-inhabiting fungi that are used for the biological control of insects. The efficiency of biocontrol is dependent on the...
Metarhizium is an important genus of soil-inhabiting fungi that are used for the biological control of insects. The efficiency of biocontrol is dependent on the maintenance of inoculum viability under adverse field conditions such as solar ultraviolet (UV) radiation. Therefore, increasing the tolerance of Metarhizium to UV radiation is necessary. It was previously established that, in mycelium, exposure to visible light increases tolerance to UV radiation. Similarly, growth under visible light for 14 days induces the production of tolerant conidia. However, a study evaluating if and how visible light affects conidia and their relationship with UV radiation was never performed. Here, we report that a relatively short and timed exposure to light around the time of conidiation is sufficient to induce the production of conidia with increased photoreactivating capacity and UV tolerance in Metarhizium acridum. Conidia produced by this method retain their characteristic higher tolerance even after many days of being transferred to the dark. Furthermore, we show that mature conidia of M. acridum and Metarhizium brunneum can still answer to light and regulate UV tolerance, suggesting that gene expression is possible even in dormant spores. Being able to respond to light in the dormant stages of development is certainly an advantage conferring improved environmental persistence to Metarhizium.
Topics: Metarhizium; Radiation Tolerance; Spores, Fungal; Time Factors; Ultraviolet Rays
PubMed: 34665247
DOI: 10.1093/femsle/fnab133 -
Journal of Radiological Protection :... Jun 2023The article is concerned with the radioprotection of a substantial radiosensitive population who present with cancer in early adulthood and will probably be treated with...
The article is concerned with the radioprotection of a substantial radiosensitive population who present with cancer in early adulthood and will probably be treated with radiotherapy. A theory of radiation-induced health effects based on the induction of DNA double strand breaks is used to associate the radio-sensitivity of carriers of the BRCA1 and BRCA2 genes and the PALB2 gene with the defects in the homologous recombination repair of DNA damage found in the carriers. It is concluded that the defects in homologous recombination repair in these carriers will lead to an increased level of somatic mutations in all their cells and that this increased level of somatic mutations throughout their lifetime is, essentially, the reason that the carriers develop early onset cancer. This is a direct consequence of the more rapid accumulation of the cancer-inducing somatic mutations than the normal, slower accumulation in non-carriers. The radiotherapeutic treatment of these carriers needs to proceed with some care, taking account of their increased radio-sensitivity, and this suggests a need for international recognition and guidance of their radioprotection within the medical profession.
Topics: Humans; DNA Damage; DNA Repair; Neoplasms; Radiation Tolerance; Female; Young Adult
PubMed: 37224796
DOI: 10.1088/1361-6498/acd857 -
International Journal of Molecular... Mar 2020Radiotherapy is an essential component of cancer therapy and remains one of the most (cost-) effective treatment options available [...].
Radiotherapy is an essential component of cancer therapy and remains one of the most (cost-) effective treatment options available [...].
Topics: Humans; Neoplasms; Radiation Tolerance; Radiotherapy
PubMed: 32150868
DOI: 10.3390/ijms21051767 -
Molecular Cancer Mar 2020Circular RNAs (circRNAs), one type of non-coding RNA, were initially misinterpreted as nonfunctional products of pre-mRNA mis-splicing. Currently, circRNAs have been... (Review)
Review
Circular RNAs (circRNAs), one type of non-coding RNA, were initially misinterpreted as nonfunctional products of pre-mRNA mis-splicing. Currently, circRNAs have been proven to manipulate the functions of diverse molecules, including non-coding RNAs, mRNAs, DNAs and proteins, to regulate cell activities in physiology and pathology. Accumulating evidence indicates that circRNAs play critical roles in tumor genesis, development, and sensitivity to radiation and chemotherapy. Radiotherapy and chemotherapy are two primary types of intervention for most cancers, but their therapeutic efficacies are usually retarded by intrinsic and acquired resistance. Thus, it is urgent to develop new strategies to improve therapeutic responses. To achieve this, clarification of the underlying mechanisms affecting therapeutic responses in cancer is needed. This review summarizes recent progress and mechanisms of circRNAs in cancer resistance to radiation and chemotherapy, and it discusses the limitations of available knowledge and potential future directions.
Topics: Animals; Biomarkers, Tumor; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Neoplasms; RNA, Circular; Radiation Tolerance
PubMed: 32171304
DOI: 10.1186/s12943-020-01180-y -
Seminars in Cancer Biology Dec 2018Cancer stem cells (CSC) possess abilities generally associated with embryonic or adult stem cells, especially self-renewal and differentiation. The CSC model assumes... (Review)
Review
Cancer stem cells (CSC) possess abilities generally associated with embryonic or adult stem cells, especially self-renewal and differentiation. The CSC model assumes that this subpopulation of cells sustains malignant growth, which suggests a hierarchical organization of tumors in which CSCs are on top and responsible for the generation of intratumoral heterogeneity. Effective tumor therapy requires the eradication of CSC as they can support regrowth of the tumor resulting in recurrence. However, eradication of CSC is difficult because they frequently are therapy resistant. Therapy resistance is mediated by the acquisition of dormancy, increased DNA repair and drug efflux capacity, decreased apoptosis as well as the interaction between CSC and their supporting microenvironment, the CSC niche. This review highlights the role of CSC in chemo- and radiotherapy resistance as well as possible ways to overcome CSC mediated therapy resistance.
Topics: ATP-Binding Cassette Transporters; Chemoradiotherapy; DNA Repair; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Neoplasms; Neoplastic Stem Cells; Radiation Tolerance; Telmisartan
PubMed: 30471331
DOI: 10.1016/j.semcancer.2018.11.006 -
Radiation Research Aug 2017Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic... (Review)
Review
Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic modalities to improve cancer treatment. LEEs have been shown to efficiently produce complex molecular damage resulting in substantial cellular toxicities. Since LEEs are produced in copious amounts from high-energy radiation beam, including photons, protons and ions; the control of LEE distribution can potentially enhance the therapeutic radio of such beams. LEEs can play a substantial role in the synergistic effect between radiation and chemotherapy, particularly halogenated and platinum-based anticancer drugs. Radiosensitizing entities containing atoms of high atomic number such as gold nanoparticles can be a source of LEE production if high-energy radiation interacts with them. This can provide a high local density of LEEs in a cell and produce cellular toxicity. Auger-electron-emitting radionuclides also create a high number of LEEs in each decay, which can induce lethal damage in a cell. Exploitation of LEEs in cancer treatment, however, faces a few challenges, such as dosimetry of LEEs and selective delivery of radiosensitizing and chemotherapeutic molecules close to cellular targets. This review first discusses the rationale for utilizing LEEs in cancer treatment by explaining their mechanism of action, describes theoretical and experimental studies at the molecular and cellular levels, then discusses strategies for achieving modification of the distribution and effectiveness of LEEs in cancerous tissue and their associated clinical benefit.
Topics: Animals; Electrons; Humans; Neoplasms; Radiation Tolerance; Radiometry; Radiotherapy
PubMed: 28557630
DOI: 10.1667/RR14727.1 -
International Journal of Radiation... Oct 2017In 2011, the International Commission on Radiological Protection reduced the threshold for the lens effects of low linear energy transfer (LET) radiation. On one hand,... (Review)
Review
PURPOSE
In 2011, the International Commission on Radiological Protection reduced the threshold for the lens effects of low linear energy transfer (LET) radiation. On one hand, the revised threshold of 0.5 Gy is much lower than previously recommended thresholds, but mechanisms behind high radiosensitivity remain incompletely understood. On the other hand, such a threshold is independent of dose rate, in contrast to previously recommended separate thresholds each for single and fractionated/protracted exposures. Such a change was made predicated on epidemiological evidence suggesting that a threshold for fractionated/protracted exposures is not higher than an acute threshold, and that a chronic threshold is uncertain. Thus, the dose rate dependence is still unclear. This paper therefore reviews the current knowledge on the radiosensitivity of the lens and the dose rate dependence of radiation cataractogenesis, and discusses its mechanisms.
CONCLUSIONS
Mounting biological evidence indicates that the lens cells are not necessarily radiosensitive to cell killing, and the high radiosensitivity of the lens thus appears to be attributable to other mechanisms (e.g., excessive proliferation, abnormal differentiation, a slow repair of DNA double-strand breaks, telomere, senescence, crystallin changes, non-targeted effects and inflammation). Both biological and epidemiological evidence generally supports the lack of dose rate effects. However, there is also biological evidence for the tissue sparing dose rate (or fractionation) effect of low-LET radiation and an enhancing inverse dose fractionation effect of high-LET radiation at a limited range of LET. Emerging epidemiological evidence in chronically exposed individuals implies the inverse dose rate effect. Further biological and epidemiological studies are warranted to gain deeper knowledge on the radiosensitivity of the lens and dose rate dependence of radiation cataractogenesis.
Topics: Animals; Cataract; Dose-Response Relationship, Radiation; Humans; Lens, Crystalline; Radiation Tolerance
PubMed: 27899034
DOI: 10.1080/09553002.2016.1266407