Relationship and interactions of curcumin with radiation therapy

Harnessing curcumin and nanotechnology for enhanced treatment of breast cancer bone metastasis

Breast cancer (BC) bone metastasis poses a significant clinical challenge due to its impact on patient prognosis and quality of life. Curcumin (CUR), a natural polyphenol compound found in turmeric, has shown potential in cancer therapy due to its anti-inflammatory, antioxidant, and anticancer properties. However, its metabolic instability and hydrophobicity have hindered its clinical applications, leading to a short plasma half-life, poor absorption, and low bioavailability. To enhance the drug-like properties of CUR, nanotechnology-based delivery strategies have been employed, utilizing polymeric, lipidic, and inorganic nanoparticles (NPs). These approaches have effectively overcome CUR's inherent limitations by enhancing its stability and cellular bioavailability both in vitro and in vivo. Moreover, targeting molecules with high selectivity towards bone metastasized breast cancer cells can be used for site specific delivery of curcumin. Alendronate (ALN), a bone-seeking bisphosphonate, is one such moiety with high selectivity towards bone and thus can be effectively used for targeted delivery of curcumin loaded nanocarriers. This review will detail the process of bone metastasis in BC, elucidate the mechanism of action of CUR, and assess the efficacy of nanotechnology-based strategies for CUR delivery. Specifically, it will focus on how these strategies enhance CUR's stability and improve targeted delivery approaches in the treatment of BC bone metastasis.

Potential Strategies for Overcoming Drug Resistance Pathways Using Propolis and Its Polyphenolic/Flavonoid Compounds in Combination with Chemotherapy and Radiotherapy

Conventional cancer treatments include surgical resection, chemotherapy, hyperthermia, immunotherapy, hormone therapy, and locally targeted therapies such as radiation therapy. Standard cancer therapies often require the use of multiple agents, which can activate nuclear factor kappa B (NF-κB) in tumor cells, leading to reduced cell death and increased drug resistance. Moreover, the use of multiple agents also contributes to added toxicity, resulting in poor treatment outcomes. Cancer cells gradually develop resistance to almost all chemotherapeutics through various mechanisms, such as drug efflux, alterations in drug metabolism and transport, changes in signal transduction pathways, enhanced DNA repair capacity, evasion of apoptosis, increased mutations, reactivation of drug targets, interaction with the cancer microenvironment, cancer cell-stroma interactions, epithelial-mesenchymal transition (EMT)-mediated chemoresistance, epigenetic modifications, metabolic alterations, and the effect of cancer stem cells (CSCs). Developing new strategies to improve chemotherapy sensitivity while minimizing side effects is essential for achieving better therapeutic outcomes and enhancing patients' quality of life. One promising approach involves combining conventional cancer treatments with propolis and its flavonoids. These natural compounds may enhance tumor response to treatment while reducing toxicity. Propolis and its components can sensitize cancer cells to chemotherapeutic agents, likely by inhibiting NF-κB activation, reprogramming tumor-associated macrophages (TAMs; an M2-like phenotype), and thereby reducing the release of matrix metalloproteinase (MMP)-9, cytokines, chemokines, and the vascular endothelial growth factor (VEGF). By reducing TAMs, propolis and its components may also overcome EMT-mediated chemoresistance, disrupt the crosstalk between macrophages and CSCs, inhibit the maintenance of stemness, and reverse acquired immunosuppression, thus promoting an antitumor response mediated by cytotoxic T-cells. This review highlights the potential of flavonoids to modulate the responsiveness of cancer to conventional treatment modalities. The evidence suggests that novel therapeutic strategies incorporating flavonoids could be developed to improve treatment outcomes. The positive effects of combining propolis with chemotherapeutics include reduced cytotoxicity to peripheral blood leukocytes, liver, and kidney cells. Therefore, polyphenolic/flavonoid components may hold potential for use in combination with chemotherapeutic agents in the clinical treatment of various types of cancers.

Effects of Curcumin on Radiation/Chemotherapy-Induced Oral Mucositis: Combined Meta-Analysis, Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

The study aims to investigate the effects of curcumin on radiation/chemotherapy-induced oral mucositis (R/CIOM) and preliminarily explore its mechanism. Randomized controlled trials were identified from the PubMed, Embase, Web of Science, Cochrane Library, Medline, and Google Scholar databases. RevMan 5.4 was used for statistical analysis to calculate the combined risk ratios (RRs). The mechanism was analyzed through network pharmacology, molecular docking, and a molecular dynamics simulation. The targets of curcumin were collected in HERB, PharmMapper, Targetnet, Swiss Target Prediction, and SuperPred. OMIM, GeneCards, and Disgenet were used to collect relevant targets for R/CIOM. Cytoscape software 3.8.0 was used to construct the component-target-pathway network. Protein-Protein Interaction (PPI) networks were constructed using the STRING database. GO and KEGG enrichment analyses were performed by Metascape. AutoDock Vina 4.2 software was used for molecular docking. The molecular dynamics simulation was performed by Gromacs v2022.03. It is found that 12 studies involving 565 patients were included. Meta-analyses showed that curcumin reduced the incidence of severe R/CIOM (RR 0.42 [0.24, 0.75]) and the mean severity of R/CIOM (MD -0.93 [-1.34, -0.52]). Eleven core target genes were identified in the treatment of R/CIOM with curcumin. The results of molecular docking and the molecular dynamics simulation showed that curcumin had strong binding energy and stability with target proteins including MAPK3, SRC, and TNF. Overall, these findings suggest curcumin can effectively improve severe R/CIOM, perhaps by affecting MAPK3, SRC, and TNF.

Evidence for the use of curcumin in radioprotection and radiosensitization

Curcumin has antineoplastic properties and is considered a chemotherapeutic and chemopreventive agent. Curcumin may be associated with radiation therapy (RT) as a radiosensitizer for cancer cells and a radioprotector for normal cells. In principle, it may result in a reduction of RT dosage for the same therapeutic effect on cancer cells, and further reduced damage to normal cells. Though the overall level of evidence is modest, limited to in vivo and in vitro experiences and practically no clinical trials, as the risks of adverse effects are extremely low, it is reasonable to promote the general supplementation with curcumin during RT targeting the reduction of side effects through anti-inflammatory mechanisms.

Cytotoxicity Enhancement in Osteosarcoma with Multifunctional I-131 Radiotherapeutic Nanoparticles: In Vitro Three-Dimensional Spheroid Model and Release Kinetics Modeling

This novel radiolabeled chitosan nanoparticle, facilitated with curcumin, increased doxorubicin cytotoxicity and radiosensitivity to MG-63 osteosarcoma cells in a three-dimensional model. Delivery of the anti-epidermal growth factor receptor (EGFR) targeted carboxymethyl chitosan nanoparticles, directly labeled with Na131I (ICED-N), achieved deep tumor penetration in a three-dimensional model. Of three kinetic models, the Higuchi model more closely matched the experimental curve and release profiles. The anti-EGFR targeting resulted in a 513-fold greater targeting efficacy to MG-63 (EGFR+) cells than the control fibroblast (EGFR-) cells. The curcumin-enhanced ICED-N (4 × 0.925 MBq) fractionated-dose regime achieved an 18.3-fold increase in cell cytotoxicity compared to the single-dose (1 × 3.70 MBq) doxorubicin-loaded nanoparticle, and a 13.6-fold increase in cell cytotoxicity compared to the single-dose Na131I nanoparticle. Moreover, the ICED-N fractionated dose increased cells in the G2/M phase 8.78-fold, indicating the cell cycle arrest in the G2/M phase is associated with DNA fragmentation, and the intracellular damage is unable to be repaired. Overall, the results indicate that the fractionated dose was more efficacious than a single dose, and curcumin substantially increased doxorubicin cytotoxicity and amplified osteosarcoma cell radiosensitivity to Na131I.

Curcumin, its derivatives, and their nanoformulations: Revolutionizing cancer treatment

Curcumin is a natural compound derived from turmeric and can target malignant tumor molecules involved in cancer propagation. It has potent antioxidant activity, but its effectiveness is limited due to poor absorption and rapid elimination from the body. Various curcumin derivatives have also shown anticancer potential in in-vitro and in-vivo models. Curcumin can target multiple signaling pathways involved in cancer development/progression or induce cancer cell death through apoptosis. In addition, curcumin and its derivatives could also enhance the effectiveness of conventional chemotherapy, radiation therapy and reduce their associated side effects. Lately, nanoparticle-based delivery systems are being developed/explored to overcome the challenges associated with curcumin's delivery, increasing its overall efficacy. The use of an imaging system to track these formulations could also give beneficial information about the bioavailability and distribution of the nano-curcumin complex. In conclusion, curcumin holds significant promise in the fight against cancer, especially in its nanoform, and could provide precise delivery to cancer cells without affecting normal healthy cells.

Comparison of the radioprotective effects of the liposomal forms of five natural radioprotectants in alleviating the adverse effects of ionising irradiation on human lymphocytes and skin cells in radiotherapy

This study aims to evaluate the radioprotective effects of liposomes encapsulating curcumin (Lip-CUR), silibinin (Lip-SIL), α-tocopherol (Lip-TOC), quercetin (Lip-QUE) and resveratrol (Lip-RES) in alleviating the adverse effects of ionising irradiation on human lymphoctyes and skin cells in radiotherapy. Liposomes encapsulating the above natural radioprotectants (Lip-NRPs) were prepared by the film hydration method combined with sonication. Their radioprotective effects for the cells against X-irradiation was evaluated using trypan-blue assay and γ-H2AX assay. All prepared Lip-NRPs had a mean diameter less than 240 nm, polydispersity index less than 0.32, and zeta potential more than -23 mV. Among them, the radioprotective effect of Lip-RES was lowest, while that of Lip-QUE was highest. Lip-SIL also exhibited a high radioprotective effect despite its low DPPH-radical scavenging activity (12.9%). The radioprotective effects of Lip-NRPs do not solely depend on the free radical scavenging activity of NRPs but also on their ability to activate cellular mechanisms.

Marasmius androsaceus mitigates depression-exacerbated intestinal radiation injuries through reprogramming hippocampal miRNA expression

INTRODUCTION

Cancer patients commonly experience high levels of psychological stress, which poses significant risks to their well-being. Radiotherapy is a primary treatment modality for cancer; however, it often leads to intestinal injuries in these patients. Nevertheless, the impact of mental stress on radiotherapy-intertwined complications remains unclear.

METHODS

To induce intestinal injury, we employed total abdominal irradiation in our experimental model. We conducted high-throughput sequencing to analyze the expression profile of miRNAs in the hippocampus.

RESULTS

We observed that mice with depression exhibited more severe intestinal injuries following total abdominal irradiation. Remarkably, oral administration of Marasmius androsaceus not only alleviated the depressive phenotype but also mitigated radiation-induced intestinal toxicity. Notably, this radioprotective effect was not observed in mice without depression. Depression disrupted the hippocampal miRNA expression profile in mice subjected to local irradiation of the abdomen, leading to the accumulation of miR-139-5p and miR-184-3p in the hippocampus, serum, and small intestine tissues. However, treatment with Marasmius androsaceus reprogrammed the miRNA expression signature in mice with depression. Furthermore, intravenous injection of antagomirs targeting miR-139-5p and miR-184-3p ameliorated depression, up-regulated Spn expression, reduced radiation enteritis, and improved the integrity of the small intestine in irradiated mice.

CONCLUSION

Our findings demonstrate the efficacy of Marasmius androsaceus, a small mushroom, in alleviating depression-aggravated intestinal toxicity following radiotherapy by reprogramming hippocampal miRNA expression.

Efficacy of curcumin for amelioration of radiotherapy-induced oral mucositis: a preliminary randomized controlled clinical trial

BACKGROUND

Oral mucositis (OM) is one of the main problems in almost all patients undergoing head and neck radiotherapy (RT). Owning to the antioxidant and anti-inflammatory properties of curcumin, the effect of both oral and topical formulations of curcumin was assessed on radiation-induced OM (ROM) in this study.

METHODS

The safety and efficacy of curcumin mouthwash 0.1% (w/v) and curcumin-nanocapsule were evaluated in ameliorating severity and pain/burning associated with OM during RT. The current randomized, placebo-controlled trial was conducted on 37 patients with head and neck cancers. Patients with grades 1 to 3 of ROM were randomized to receive one of the three interventions: curcumin mouthwash (0.1% w/v); Sinacurcumin soft gel containing 40 mg curcuminoids as nano-micelles (SinaCurcumin®40); or placebo mouthwash with a similar transparent appearance to curcumin mouthwash for 1 min three times daily during RT. Study evaluations were conducted at baseline and weekly thereafter for up to 3 weeks using the Numeric rating scale (NRS) and world health organization (WHO) scale.

RESULTS

Among the 45 patients randomized, 37 (mean (SD) age of 53.36 (15.99) years; 14 [37.8%] women) completed the treatment according to the protocol. Patients treated with either oral or topical curcumin showed a significantly reduced severity and burning related to OM during the first 3 weeks after administration (P-Value < 0.001) as compared with the placebo. At study termination, more than 33% of subjects utilizing curcumin mouthwash and 15% of patients utilizing curcumin-nanocapsule remained ulcer free while all of the placebo-receiving subjects had OM. The reduction of NRS and WHO scale between curcumin groups was comparable without significant differences.

CONCLUSION

Both curcumin mouthwash and nanocapsule were effective, safe, and well-tolerated in the treatment of radiation-induced OM. Higher doses of curcumin and larger sample sizes can be used for further investigation in future studies.

TRIAL REGISTRATION

https://irct.ir/ IRCT20190810044500N17 (13/08/2021).

Functionalization of curcumin nanomedicines: a recent promising adaptation to maximize pharmacokinetic profile, specific cell internalization and anticancer efficacy against breast cancer

Owing to its diverse heterogeneity, aggressive nature, enormous metastatic potential, and high remission rate, the breast cancer (BC) is among the most prevalent types of cancer associated with high mortality. Curcumin (Cur) is a potent phytoconstituent that has gained remarkable recognition due to exceptional biomedical viability against a wide range of ailments including the BC. Despite exhibiting a strong anticancer potential, the clinical translation of Cur is restricted due to intrinsic physicochemical properties such as low aqueous solubility, chemical instability, low bioavailability, and short plasma half-life. To overcome these shortcomings, nanotechnology-aided developments have been extensively deployed. The implication of nanotechnology has pointedly improved the physicochemical properties, pharmacokinetic profile, cell internalization, and anticancer efficacy of Cur; however, majority of Cur-nanomedicines are still facing grandeur challenges. The advent of various functionalization strategies such as PEGylation, surface decoration with different moieties, stimuli-responsiveness (i.e., pH, light, temperature, heat, etc.), tethering of specific targeting ligand(s) based on the biochemical targets (e.g., folic acid receptors, transferrin receptors, CD44, etc.), and multifunctionalization (multiple functionalities) has revolutionized the fate of Cur-nanomedicines. This study ponders the biomedical significance of various Cur-nanomedicines and adaptable functionalizations for amplifying the physicochemical properties, cytotoxicity via induction of apoptosis, cell internalization, bioavailability, passive and active targeting to the tumor microenvironment (TME), and anticancer efficacy of the Cur while reversing the multidrug resistance (MDR) and reoccurrence in BC. Nevertheless, the therapeutic outcomes of Cur-nanomedicines against the BC have been remarkably improved after adaptation of various functionalizations; however, this evolving strategy still demands extensive research for scalable clinical translation.

In-vivo and in vitro assessments of the radioprotective potential natural and chemical compounds: a review

PURPOSE

The study of the radioactive role of natural and chemical substances on human and animal studies has been the subject of research by some researchers. Therefore, the review of some of the past and current studies conducted in this field, can provide helpful information to elucidate of the importance of radioprotective components in reducing radiation exposure side effects.

METHODS

The authors search for keywords including In vitro, In vivo, Radioprotective, Ionizing radiation, and Vitamin in ScienceDirect, Scopus, Pubmed, and Google Scholar databases to access previously published articles and search for more reference articles on the role of radioprotective materials from natural and chemical compounds.

RESULTS

Radiation exposure can produce reactive oxygen species (ROS) in the body, however most of which are eliminated by the body's natural mechanisms, but when the body's antioxidant systems do not have enough ability to neutralize free radicals, oxidative stress occurs, which causes damage to DNA and body tissues. Therefore, it is necessary use of alternative substances that reduce and inhibit free radicals.

CONCLUSION

In general, recommended that antioxidant component(s) can be protect tissue damages in humans or animals, due to the their ability to scavenge free radicals generated by ionizing radiation.

A High Throughput Screen with a Clonogenic Endpoint to Identify Radiation Modulators of Cancer

Clonogenic assays evaluate the ability of single cells to proliferate and form colonies. This process approximates the regrowth and recurrence of tumors after treatment with radiation or chemotherapy, and thereby provides a drug discovery platform for compounds that block this process. However, because of their labor-intensive and cumbersome nature, adapting canonical clonogenic assays for high throughput screening (HTS) has been challenging. We overcame these barriers by developing an integrated system that automates cell- and liquid-handling, irradiation, dosimetry, drug administration, and incubation. Further, we developed a fluorescent live-cell based automated colony scoring methodology that identifies and counts colonies precisely based upon actual nuclei number rather than colony area, thereby eliminating errors in colony counts caused by radiation induced changes in colony morphology. We identified 13 cell lines from 7 cancer types, where radiation is a standard treatment module, that exhibit identical radiation and chemoradiation response regardless of well format and are amenable to miniaturization into small-well HTS formats. We performed pilot screens through a 1,584 compound NCI Diversity Set library using two cell lines representing different cancer indications. Radiation modulators identified in the pilot screens were validated in traditional clonogenic assays, providing proof-of-concept for the screen. The integrated methodology, hereafter "clonogenic HTS", exhibits excellent robustness (Z' values > 0.5) and shows high reproducibility (>95%). We propose that clonogenic HTS we developed can function as a drug discovery platform to identify compounds that inhibit tumor regrowth following radiation therapy, to identify new efficacious pair-wise combinations of known oncologic therapies, or to identify novel modulators ofapproved therapies.

Review of compounds that exhibit radioprotective and/or mitigatory effects after application of diagnostic or therapeutic ionizing radiation

PURPOSE

Exposure to ionizing radiation can be accidental or for medical purposes. Analyzes of the frequency of radiation damage in the general population, it has been determined that by far the most common are those that occur as a result of diagnostic or therapeutic procedures. Damage caused by radiation, either accidentally or for therapeutic purposes, can be reduced by the use of radioprotectors, mitigators or other therapeutic agents. A detailed research of the available literature shows that there is little systematized data of potentially radioprotective and/or mitigating effects of drugs from the personal therapy of patients during the application of therapeutic ionizing radiation. The aim of this paper is to present review of compounds, especially personal therapy drugs, that exhibit radioprotective and/or mitigating effects after the application of diagnostic or therapeutic ionizing radiation.

CONCLUSIONS

Given the widespread use of ionizing radiation for diagnostic and therapeutic purposes, there is a clear need to create a strategy and recommendations of relevant institutions for the use of radioprotectors and mitigators in everyday clinical practice, with individual evaluation of the patient's condition and selection of the compounds that will show the greatest benefit in terms of radioprotection.

Protective Role of Natural Compounds under Radiation-Induced Injury

In recent years, evidence has shown the potential therapeutic effects of different natural compounds for the prevention and treatment of radiotherapy-induced mucositis (RIOM). RIOM represents one of the most frequent side effects associated with anti-neoplastic treatments affecting patients' quality of life and treatment response due to radiation therapy discontinuation. The innate radio-protective ability of natural products obtained from plants is in part due to the numerous antioxidants possessed as a part of their normal secondary metabolic processes. However, oxygen presence is a key point for radiation efficacy on cancer cells. The aim of this review is to describe the most recent evidence on radiation-induced injury and the emerging protective role of natural compounds in preventing and treating this specific damage without compromising treatment efficacy.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Interaction of curcumin with glioblastoma cells via high and low linear energy transfer radiation therapy inducing radiosensitization effects

Glioblastoma is a deadly cancer tumor in the brain and has a survival rate of about 15 months. Despite the high mortality rate, temozolomide has proven to increase the survival rate of patients when combined with radiotherapy. However, its effects may be limited because some patients develop therapeutic resistance. Curcumin has proven to be a cancer treatment due to its broad anticancer spectrum, high efficiency and low toxic level. Additionally, curcumin significantly enhanced radiation efficacy under high and low Linear Energy Transfer (LET) radiation conditions in vitro. In combination with radiation, curcumin increased the cell population in the sub-G1 phase and the reactive oxygen species (ROS) level, ultimately increasing GBM cellular apoptosis. The radiosensitizing effects of curcumin are much higher in neutron (high LET)-irradiated cell lines than in γ (low LET)-irradiated cell lines. Curcumin plus neutron combination significantly inhibited cell invasion compared with that of single treatment or curcumin combined γ-ray treatment. Curcumin enhances the radiosensitivity of Glioblastoma (GBM), suggesting it may have clinical utility in combination cancer treatment with neutron high-LET radiation.

Phytochemicals Targeting Oxidative Stress, Interconnected Neuroinflammatory, and Neuroapoptotic Pathways Following Radiation

The radiation for therapeutic purposes has shown positive effects in different contexts; however, it can increase the risk of many age-related and neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Parkinson's disease (PD). These different outcomes highlight a dose-response phenomenon called hormesis. Prevailing studies indicate that high doses of radiation could play several destructive roles in triggering oxidative stress, neuroapoptosis, and neuroinflammation in neurodegeneration. However, there is a lack of effective treatments in combating radiation-induced neurodegeneration, and the present drugs suffer from some drawbacks, including side effects and drug resistance. Among natural entities, polyphenols are suggested as multi-target agents affecting the dysregulated pathogenic mechanisms in neurodegenerative disease. This review discusses the destructive effects of radiation on the induction of neurodegenerative diseases by dysregulating oxidative stress, apoptosis, and inflammation. We also describe the promising effects of polyphenols and other candidate phytochemicals in preventing and treating radiation-induced neurodegenerative disorders, aiming to find novel/potential therapeutic compounds against such disorders.

Anticancer agent α-sulfoquinovosyl-acylpropanediol enhances the radiosensitivity of human malignant mesothelioma in nude mouse models

Malignant pleural mesothelioma (MPM) is a highly malignant disease that develops after asbestos exposure. Although the number of MPM cases is predicted to increase, no effective standard therapies have been established. The novel radiosensitizer α-sulfoquinovosyl-acylpropanediol (SQAP) enhances the effects of γ-radiation in human lung and prostate cancer cell lines and in animal models. In this study, we explored the radiosensitizing effect of SQAP and its mechanisms in MPM. The human MPM cell lines MSTO-211H and MESO-4 were implanted subcutaneously into the backs and thoracic cavities of immunodeficient KSN/Slc mice, then 2 mg/kg SQAP was intravenously administered with or without irradiation with a total body dose of 8 Gy. In both the orthotopic and ectopic xenograft murine models, the combination of irradiation plus SQAP delayed the implanted human MSTO-211H tumor growth. The analysis of the changes in the relative tumor volume of the MSTO-211H indicated a statistically significant difference after 8 Gy total body combined with 2 mg/kg SQAP, compared to both the untreated control (P = 0.0127) and the radiation treatment alone (P = 0.0171). After the treatment in each case, immunostaining of the harvested tumors revealed decreased cell proliferation, increased apoptosis and normalization of tumor blood vessels in the SQAP- and irradiation-treated group. Furthermore, hypoxia-inducible factor (HIF) 1 mRNA and protein expression were decreased, indicating reoxygenation in this group. In conclusion, SQAP improved hypoxic conditions in tumor tissue and may elicit a radiosensitizing effect in malignant mesothelioma models.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.

Natural radioprotectors on current and future perspectives: A mini-review

Radiation therapy is used as the primary treatment for cancer. Eighty percent of cancer patients require radiation therapy during treatment or for medical purposes. During treatment, radiation causes various biological defects in the cells. The prevalence of cytotoxicity limits the dose used for effective treatment. This method is designed to strike a balance between removing cancer cells and protecting normal tissues. Unfortunately, effective radiation is unavailable once acute toxicity occurs during clinical radiation therapy. Therefore, a lot of research interest is needed in the discovery of radioprotective drugs to accelerate treatment to reduce this toxicity (i.e., normal tissue toxicity to cancer cell death). Radiation protectors may be chemicals or drugs that minimize the damage caused due to radiation therapy in living organisms. The determination of effective and nontoxic radiation protection is an essential goal for radiation oncologists and basic radiobiologists. However, despite the advantages, many radioprotectors were found to have disadvantages which include cost, less duration, toxicity, and effect on the central nervous system. Therefore in recent years, the focus has been diverted to finding out optimal natural products to act as radioprotectors. Natural radiation protectors are plant compounds that protect normal (noncancerous) cells from damage from radiation therapy. Natural herbal products are nontoxic with proven therapeutic benefits and have long been used to treat various diseases. In conclusion, we find that there are various radiation protectors with different purposes and mechanisms of action.

Ultrasound augments on-demand breast tumor radiosensitization and apoptosis through a tri-responsive combinatorial delivery theranostic platform

Advanced inoperable triple-negative breast cancer (TNBC) comprises aggressive tumors with a modest pathological response to neoadjuvant chemotherapy. The concomitant use of chemoradiotherapy improves the pathological response rates. However, the dose-dependent systemic toxicity of clinical radiosensitizers with poor circulation half-life and limited passive bioavailability limits their clinical utility. We address these challenges by rationally designing a stealth and tumor microenvironment responsive nano-conjugate platform for the ultrasound-mediated on-demand spatio-temporal delivery of plant flavonoid curcumin as a combinatorial regimen with clinically approved paclitaxel for the neoadjuvant chemoradiotherapy of locally advanced triple-negative breast cancer (TNBC). Interestingly, the focused application of ultrasound at the orthotopic TNBC xenograft of NOD-SCID mice facilitated the immediate infiltration of nano-conjugates at the tumor interstitium, and conferred in vivo safety over marketed paclitaxel formulation. In addition, curcumin significantly potentiated the in vivo chemoradiotherapeutic efficacy of paclitaxel upon loading into nano-conjugates. This gets further enhanced by the concurrent pulse of ultrasound, as confirmed by PET-CT imaging, along with a significant improvement in the mice survival. The quadrapeutic apoptotic effect by the combination of paclitaxel, curcumin, radiation, and ultrasound, along with a reduction in the tumor microvessel density and cell proliferation marker, confers the broad chemo-radiotherapeutic potential of this regimen for radio-responsive solid tumors, as well as metastatic niches.

Radiosensitizing Effect of Curcumin on Human Bladder Cancer Cell Lines: Impact on DNA Repair Mechanisms

Chemo-radiotherapy is one of the promising approaches to treat bladder cancer, but its effectiveness is limited to sensitive patients. Polyphenol curcumin has shown anticancer and radiosensitizing potentials, but the mechanism is not fully understood. Here, the In Vitro response of UM-UC5 and UM-UC6 bladder cell lines to curcumin and radiation treatments was evaluated. The effect of curcumin on the DNA double-strand breaks repair system after treatment with ionizing radiation (2 Gy) was determined by immunofluorescence. Cell viability, proliferation, and survival were performed using trypan blue, MTT, clonogenic, and sphere-forming assays. The migratory ability of both cells was assessed by wound healing. We showed that curcumin treatment increased the radiosensitivity by modifying the DNA double-strand breaks repair kinetics of the most radioresistant cells UM-UC6 without affecting the radiosensitive UM-UC5. Moreover, UM-UC6 cell survival and proliferation was significantly decreased after the combination of curcumin with radiation. Bladder cell migration was also inhibited considerably. Curcumin was also shown to reduce the number and the volume of bladder cancer spheres of both cell lines. This study revealed that curcumin was able to radiosensitize resistant bladder cell line without affecting the sensitive one with minimal side effects through enhancing DNA damage signaling and repair pathway.

Could Polyphenols Really Be a Good Radioprotective Strategy?

Currently, radiotherapy is one of the most effective strategies to treat cancer. However, deleterious toxicity against normal cells indicate for the need to selectively protect them. Reactive oxygen and nitrogen species reinforce ionizing radiation cytotoxicity, and compounds able to scavenge these species or enhance antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) should be properly investigated. Antioxidant plant-derived compounds, such as phenols and polyphenols, could represent a valuable alternative to synthetic compounds to be used as radio-protective agents. In fact, their dose-dependent antioxidant/pro-oxidant efficacy could provide a high degree of protection to normal tissues, with little or no protection to tumor cells. The present review provides an update of the current scientific knowledge of polyphenols in pure forms or in plant extracts with good evidence concerning their possible radiomodulating action. Indeed, with few exceptions, to date, the fragmentary data available mostly derive from in vitro studies, which do not find comfort in preclinical and/or clinical studies. On the contrary, when preclinical studies are reported, especially regarding the bioactivity of a plant extract, its chemical composition is not taken into account, avoiding any standardization and compromising data reproducibility.

Curcumin Enhances the Radiosensitivity of Human Urethral Scar Fibroblasts by Apoptosis, Cell Cycle Arrest and Downregulation of Smad4 via Autophagy

The goals of this study were to determine whether curcumin can radiosensitize human urethral scar fibroblasts (HUSFs) and inhibit the synthesis of collagen, and to explore the molecular mechanism. Here, HUSFs were established and cultured in vitro and cell counting kit-8 (CCK-8) experiment and plate clone formation assay were performed to determine the appropriate concentration of curcumin and radiation dose. The radiosensitization of curcumin was confirmed by plate clone formation assay. Cell cycle distribution was determined by flow cytometry and apoptosis rate by TdT-mediated dUTP nick-end labeling (TUNEL). Western blot was used to detect the levels of collagen I, collagen III, Smad2, Smad3, Smad4, transforming growth factor-β (TGF-β1), Beclin1 and microtubule-associated protein light chain 3 (LC3), as a means of determining the mechanism. Our findings showed that curcumin enhanced radiosensitivity of HUSFs in vitro (sensitization enhancement ratio = 2.030). Furthermore, curcumin and radiation treatments promoted the apoptosis of HUSFs and blocked the cells in G2/M phase. In addition, curcumin combined with radiation inhibited the synthesis of collagen I and collagen III through Smad4 pathway, with possible involvement of autophagy. These results suggest that curcumin could be a radiosensitizer of HUSFs, inhibit the proliferation of HUSFs and suppress fibrosis by downregulation of Smad4 via autophagy.

Application of Radiosensitizers in Cancer Radiotherapy

Radiotherapy (RT) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. Although great success has been achieved on radiotherapy, there is still an intractable challenge to enhance radiation damage to tumor tissue and reduce side effects to healthy tissue. Radiosensitizers are chemicals or pharmaceutical agents that can enhance the killing effect on tumor cells by accelerating DNA damage and producing free radicals indirectly. In most cases, radiosensitizers have less effect on normal tissues. In recent years, several strategies have been exploited to develop radiosensitizers that are highly effective and have low toxicity. In this review, we first summarized the applications of radiosensitizers including small molecules, macromolecules, and nanomaterials, especially those that have been used in clinical trials. Second, the development states of radiosensitizers and the possible mechanisms to improve radiosensitizers sensibility are reviewed. Third, the challenges and prospects for clinical translation of radiosensitizers in oncotherapy are presented.

Tumor cell membrane-derived nano-Trojan horses encapsulating phototherapy and chemotherapy are accepted by homologous tumor cells

Tumor cell membrane-derived nanostructures targeting homologous tumors are promising biomimetic drugs. Herein, curcumin (Cur) and chlorin e6 (Ce6) were co-loaded into PLGA nanoparticles (NPs), and then the NPs were coated with MCF-7 cell membranes (MCNPs). Cell membrane coating sharply increased the uptake of MCNPs by homologous cells, as compared to that with naked NPs. The NPs co-loaded with Cur and Ce6 (Cur/Ce6-NPs) showed a stronger proliferation-inhibitory effect on MCF-7 cells than the NP groups loaded with Cur and Ce6 alone. Cytotoxicity and apoptosis rates of MCF-7 cells in the Cur/Ce6-MCNPs group were significantly higher than those in the uncoated Cur/Ce6-NPs group. Both Cur/Ce6-NPs and Cur/Ce6-MCNPs significantly inhibited the migration of MCF-7cells, although Cur/Ce6-MCNPs showed a stronger effect. Compared to that of Cur/Ce6-NPs, the elimination of Cur/Ce6-MCNPs was both decreased and retarded, prolonging their in vivo systemic circulation and resulting in improved bioavailability. After intravenous administration for 24 h, the fluorescence intensity of drugs in the liver and spleen of the Cur/Ce6-MCNPs group was significantly weaker than that in the Cur/Ce6-NPs group, but that in tumor tissue was enhanced. Further, Cur/Ce6-MCNPs treatment achieved significantly better tumor-suppressive effects in vivo than Cur/Ce6-NPs, resulting in smaller tumor weights, increased apoptosis rates, and the down regulation of Ki67 protein in the tumor tissue. Thus, the tumor cell membrane-camouflaged nanocomposites have potential for homologous tumor-targeted therapy. Furthermore, photodynamic therapy combined with chemotherapy has promising future prospects.

Protection Against Radiation-Induced Duox1 and Duox2 Upregulation in Rat's Lung Tissues by a Combination of Curcumin and L-Selenomethionine

Background: It has been proposed that increased levels of pro-inflammatory and pro-fibrotic cytokines play a key role in radiation-induced lung injury. Interleukin-4 (IL-4) and IL-13 are two pro-fibrotic cytokines that promote the production of free radicals through stimulation of Duox1 and Duox2. In this experimental study, we aimed to evaluate the expression of IL4Ra1, Duox1, IL13Ra2, and Duox2 genes following rat’s lung irradiation. Objectives: Also, we detected the modulatory effect of a combination of curcumin and L-selenomethionine on the expression of these genes. Methods: Twenty male rats were divided into four groups as G1: control (no treatment or radiation); G2: treatment with a combination of curcumin and L-selenomethionine; G3: radiation; G4: radiation plus a combination of curcumin and L-selenomethionine. sixty-seven days after irradiation, rats were killed for detecting the expression of IL4Ra1, IL13Ra2, Duox1, and Duox2. Results: The results showed no detectable expression for IL13Ra2, while the expression of IL4Ra1, Duox1, and Duox2 was increased. Treatment with a combination of curcumin and L-selenomethionine could attenuate the expression of these genes. Conclusions: This study proposes that upregulation of Duox1 and Duox2 may be involved in radiation-induced lung injury. Treatment with a combination of curcumin and L-selenomethionine may be useful for the mitigation of lung injury through modulation of these genes.

Curcumin protects radiation-induced liver damage in rats through the NF-κB signaling pathway

BACKGROUND

Curcumin has been demonstrated to exert anti-oxidant, anti-fibrotic, anti-inflammatory, and anti-cancer activities. This study was conducted to observe the effect and inner mechanism of curcumin in rats with radiation-induced liver damage (RILD).

METHODS

Thirty SD rats were classified into Control, Radiation group and Curcumin (Cur) + Radiation group (n = 10 in each group). The changes in body weight of the rats were observed on the 3rd, 7th and 14th days after the treatment with curcumin. On the 14th day post treatment, the heart blood of the rats was drawn for measurement of liver function indices including total protein (TP), alanine aminotransfetase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) as well as aspartate aminotransfetase (AST). Subsequently, the rats were euthanized and liver tissues were taken to observe liver morphological changes using hematoxylin-eosin (HE), and to analyze apoptosis condition using transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assays. Meanwhile, the oxidative stress level in liver tissue homogenate was determined by biochemical analysis. The expression of nuclear factor kappa B (NF-κB) pathway-associated and apoptosis-associated proteins was detected using Western blot analysis, and the expression levels of inflammatory factors were measured by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

The reduced body weight was observed in rats of the Radiation group compared to the Control and Cur + Radiation groups on day 14. In the Radiation group, hepatic cell edema and inflammatory cell infiltration could be visible under the light microscope, and the hepatocytes presented with vacuolar degeneration. In the Cur + Radiation group, the hepatocytes swelled under the microscope, but the pathological changes were alleviated in comparison with the Radiation group. RILD rats with curcumin treatment presented with decreased ALT, AST, ALP, LDH, and maleicdialdehyde (MDA) levels, and elevated TP, superoxide dismutase (SOD), caspase activated DNase (CAD) and glutathione (GSH) levels. Apoptosis and inflammation in rats with RILD were up-regulated, and the NF-κB pathway was activated, but they were reversed after continuously intragastric administration of curcumin for 14 days.

CONCLUSION

Our study highlights that curcumin treatment reduces the liver damage caused by radiation through the inhibition of the NF-κB pathway.

Potential of natural products as radioprotectors and radiosensitizers: opportunities and challenges

Natural products can be used as natural radiosensitizers and radioprotectors, showing promising effects in cancer treatments in combination with radiotherapy, while reducing ionizing radiation (IR) damage to normal cells/tissues. The different effects of natural products on irradiated normal and tumor cells/tissues have attracted more and more researchers' interest. Nonetheless, the clinical applications of natural products in radiotherapy are few, which may be related to their low bioavailability in the human body. Here, we displayed the radiation protection and radiation sensitization of major natural products, highlighted the related molecular mechanisms of these bioactive substances combined with radiotherapy to treat cancer, and critically reviewed their deficiency and improved measures. Lastly, several clinical trials were presented to verify the clinical application of natural products as radiosensitizers and radioprotectors. Further clinical evaluation is still needed. This review provides a reference for the utilization of natural products as radiosensitizers and radioprotectors.

Curcumin and Glu-GNPs Induce Radiosensitivity against Breast Cancer Stem-Like Cells

Breast cancer stem cells are an important cause of radiotherapy resistance in the clinical treatment of breast cancer patients. How to target breast cancer stem cells is the key to improving the efficacy of breast cancer radiotherapy. We proposed for the first time that curcumin combined with glucose nanogold particles (Glu-GNPs) targeted breast cancer stem cells to reduce radiotherapy resistance, which can significantly enhance the apoptosis level of MCF-7 and MDA-MB-231 breast cancer stem-like cells (BCSCs) after radiotherapy and antiproliferation and colony-forming. Under simulated hypoxic conditions, curcumin combined with Glu-GNPs can significantly improve the ROS level of MCF-7 and MDA-MB-231 mammospheres; reduce the expression of HIF-1α and HSP90, thereby inhibiting the tumor cells' own stress ability; promote the apoptosis of tumor stem cells; and enhance the sensitivity of radiotherapy. The current results indicate that the combination of curcumin and Glu-GNPs has great potential to relieve tumor hypoxia and increase radiosensitivity on BCSCs, providing scientific research data for developing a novel radiosensitizer with high efficiency and low toxicity.

Development and Evaluation of Paclitaxel and Curcumin Dry Powder for Inhalation Lung Cancer Treatment

Despite the effort to develop efficient targeted drug delivery for lung cancer treatment, the outcome remains unsatisfactory with a survival rate of 15% after 5 years of diagnosis. Inhalation formulation is an ideal alternative that could ensure the direct deposition of chemotherapeutics to the lungs. However, the design of an inhalable formulation that could simultaneously achieve a high local chemotherapeutic dose to the solid tumor and exert low pulmonary toxicities is a challenge, as the presence of 10–30% of chemotherapeutics in the lung is sufficient to induce toxicity. Therefore, this study aimed to develop a simple dry powder inhalation (DPI) formulation containing a model chemotherapeutic agent (paclitaxel, PTX) and a natural antioxidant (curcumin, CUR) that acts to protect healthy lung cells from injury during direct lung delivery. The co-jet-milling of CUR and PTX resulted in formulations with suitable aerosol performance, as indicated in the high fine particle fractions (FPF) (>60%) and adequate mass median aerodynamic diameter (MMAD). The CUR/PTX combination showed a more potent cytotoxic effect against lung cancer cells. This is evident from the induction of apoptosis/necrotic cell death and G2/M cell cycle arrests in both A549 and Calu-3 cells. The increased intracellular ROS, mitochondrial depolarization and reduced ATP content in A549 and Calu-3 cells indicated that the actions of CUR and PTX were associated with mitochondrial oxidative stress. Interestingly, the presence of CUR is crucial to neutralize the cytotoxic effects of PTX against healthy cells (Beas-2B), and this is dose-dependent. This study presents a simple approach to formulating an effective DPI formulation with preferential cytotoxicity towards lung cancer.

Experimental and clinical studies on radiation and curcumin in human glioma

Purpose

There is progressing evidence for the anti-cancer potential of the natural compound and dietary spice curcumin. Curcumin has been ascribed to be cytotoxic for various tumour cell types, to inhibit cell proliferation and to interfere with the cellular oxidant status. The compound has been notified as a therapeutic agent with radiosensitizing potential in brain tumour therapy. We considered the rationale to combine curcumin with radiation in the treatment of human glioblastoma multiforme (GBM).

Method

Determination of clonogenic cell survival following exposure of U251 human glioma cells to single dose (1–6 Gy) and fractionated irradiation (5 daily fractions of 2 Gy) without and with curcumin. Additional literature search focused on the interaction between curcumin and radiotherapy in experimental and clinical studies on human glioma.

Results

No interaction was found on the survival of U251 human glioma cells after irradiation in combination with curcumin at clinically achievable concentrations. Experimental in vitro and in vivo data together with clinical bioavailability data from the literature do not give evidence for a radiosensitizing effect of curcumin. Reported GBM intratumoural curcumin concentrations are too low to either exert an own cytotoxic effect or to synergistically interact with radiation. Novel approaches are being explored to increase the bioavailability of curcumin and to facilitate transport over the blood–brain barrier, aimed to reach therapeutic curcumin levels at the tumour site.

Conclusion

There is neither a biological nor clinical rationale for using curcumin as radiosensitizer in the therapy of GBM patients.

Curcumin's Beneficial Effects on Neuroblastoma: Mechanisms, Challenges, and Potential Solutions

Curcumin, a natural polyphenolic compound derived from the South Asian turmeric plant (Curcuma longa), has well-characterized antioxidant, anti-inflammatory, anti-protein-aggregate, and anticancer properties. Neuroblastoma (NB) is a cancer of the nervous system that arises primarily in pediatric patients. In order to reduce the multiple disadvantages and side effects of conventional oncologic modalities and to potentially overcome cancer drug resistance, natural substances such as curcumin are examined as complementary and supportive therapies against NB. In NB cell lines, curcumin by itself promotes apoptosis and cell cycle arrest through the suppression of serine–threonine kinase Akt and nuclear factor kappa of activated B-cells (NF-κB) signaling, induction of mitochondrial dysfunction, and upregulation of p53 and caspase signaling. While curcumin demonstrates anti-NB efficacy in vitro, cross-validation between NB cell types is currently lacking for many of its specific mechanistic activities. Furthermore, curcumin’s low bioavailability by oral administration, poor absorption, and relative insolubility in water pose challenges to its clinical introduction. Numerous curcumin formulations, including nanoparticles, nanocarriers, and microemulsions, have been developed, with these having some success in the treatment of NB. In the future, standardization and further basic and preclinical trials will be required to ensure the safety of curcumin formulations. While the administration of curcumin is clinically safe even at high doses, clinical trials are necessary to substantiate the practical efficacy of curcumin in the prevention and treatment of NB.

Radio-sensitizing effect of a cocktail of phytochemicals on HepG2 cell proliferation, motility and survival

Radio-resistance is a major hurdle challenging oncologist worldwide. Despite their anti-cancer characteristics, the implication of phytochemicals in clinical trials is still limited. This study is designed to evaluate the anticancer characteristics and radio-sensitizing effect of a cocktail of seven phytochemicals on HepG2 cells. Characterization of phytochemicals combination phenolic and flavonoids content as well as their scavenging activity were tested. The effective concentration of BSG that will be used as a radio-sensitizing dose was calculated using AlamarBlue assay. Treatment of HepG2 cells with BSG and/or ionizing radiations led to significant downregulation at cell proliferation as indicated by the decrease of colony formation ratio, proliferation marker (Ki67) expression as well as G2/M cell cycle arrest. The combined treatment stimulated P53-dependent apoptosis which was indicated by the significant increase of early apoptosis marker (Annexin V) expression, DNA fragmentation, expression of P53 & Bax and downregulation of Bcl2 expression. Combined treatment significantly attenuated HepG2 cell motility which was validated using wound healing migration assay and the significant reduction at CD95 expression. This study demonstrates the anti-cancer effect of BSG and its fundamental role in provoking cell responsiveness to IR leading to a significant inhibition at HepG2 cell proliferation, survival and migration.

Prophylactic and Therapeutic Effects of Curcumin on Treatment-Induced Oral Mucositis in Patients with Head and Neck Cancer: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Clinical trials have explored the role of curcumin in the prevention and treatment of oral mucositis (OM) in head and neck cancer patients. To provide evidence for curcumin management of OM for clinicians, a comprehensive meta-analysis of these findings is necessary. This meta-analysis aimed to evaluate the efficacy and safety of curcumin for OM caused by radiotherapy (RT) and/or chemotherapy (CT) for head and neck cancer.

METHODS

Randomized controlled trials were identified from the PubMed, Embase, Web of Science, Cochrane Library, Medline, and Google Scholar databases. RevMan 5.3 was used for statistical analysis to calculate the combined risk ratios (RRs).

RESULTS

Six studies involving 266 patients were included. Curcumin considerably reduced weight loss (mean difference [MD] - 0.78) in both the prophylactic and therapeutic phases. When used as a preventative treatment, curcumin did not reduce the incidence of OM (RR 0.99), but it did reduce the incidence of severe OM (RR 0.44) and the mean severity of OM (SMD -1.44). Curcumin also reduced the severity of OM (MD 0.82) compared to chlorhexidine.

CONCLUSION

Curcumin is a safe, natural bioactive substance that can effectively prevent and treat OM in patients receiving RT and/or CT, as well as reduce weight loss.

Amelioration of Radiation-Induced Damages in Mice by Curcuminoids: The Role of Bioavailability

PURPOSE

The present study investigated the role of free curcuminoids bioavailability on the relative radioprotective efficacy of natural unformulated curcuminoids.

MATERIALS AND METHODS

A food-grade bioavailable formulation of curcuminoids as curcumagalactomannosides (CGM) and unformulated curcuminoids (UC) were employed for the study. Swiss albino mice were randomized into Normal control, Radiation control, Radiation + UC, and Radiation + CGM groups and irradiated with γ-radiation of 6, 8, 10 and 12 Gy. Survival rate, hematological and biochemical parameters, bone marrow cellularity, chromosomal aberrations and histopathology of intestine were followed as a measure of the relative efficacy.Results and Discussion: Oral administration with both UC and CGM at 100 mg/kg. b.wt. produced significant radioprotective effect over the untreated control group of animals. However, CGM treatment was found to provide better clastogenic and genotoxic potential as compared to UC. Further, the histopathology analysis of intestine confirmed the better protective effect of CGM over UC-treated animals.

CONCLUSION

The present study demonstrated the positive role of the bioavailability of curcuminoids in the amelioration of radiation-induced damages in mice since CGM treatment exerted better survival rate and radioprotective effect as compared with UC, despite the relatively low concentrations of curcuminoids in CGM (39% w/w).

Modification of radiosensitivity by Curcumin in human pancreatic cancer cell lines

Pancreatic cancer is one of the most aggressive malignancies and is characterized by a low 5-year survival rate, a broad genetic diversity and a high resistance to conventional therapies. As a result, novel therapeutic agents to improve the current situation are needed urgently. Curcumin, a polyphenolic colorant derived from Curcuma longa root, showed pleiotropic influences on cellular pathways in vitro and amongst others anti-cancer properties including sensitization of tumor cells to chemo- and radiation-therapy. In this study, we evaluated the impact of Curcumin on the radiosensitivity of the established human pancreatic cancer cell lines Panc-1 and MiaPaCa-2 in vitro. In contrast to MiaPaCa-2 cells, we found a significant radiosensitization by Curcumin in the more radioresistant Panc-1 cells, possibly caused by cell cycle arrest in the most radiation-sensitive G2/M-phase at the time of irradiation. Furthermore, a significant enhancement of radiation-induced apoptosis, DNA-double-strand breaks and G2/M-arrest after curcumin treatment was observed in both cell lines. These in vitro findings suggest that especially patients with more radioresistant tumors could benefit from a radiation-concomitant, phytotherapeutic therapy with Curcumin.

Utility of topical agents for radiation dermatitis and pain: a randomized clinical trial

PURPOSE

Although topical agents are often provided during radiation therapy, there is limited consensus and evidence for their use prophylactically to prevent or reduce radiation dermatitis.

METHODS

This was a multi-site, randomized, placebo-controlled, blinded study of 191 breast cancer patients to compare the prophylactic effectiveness of three topical agents (Curcumin, HPR Plus™, and Placebo) for reducing radiation dermatitis and associated pain. Patients applied the topical agent to their skin in the radiation area site three times daily starting the first day of radiation therapy (RT) until 1 week after RT completion.

RESULTS

Of the 191 randomized patients, 171 patients were included in the final analyses (87.5% white females, mean age = 58 (range = 36-88)). Mean radiation dermatitis severity (RDS) scores did not significantly differ between study arms (Curcumin = 2.68 [2.49, 2.86]; HPR Plus™ = 2.64 [2.45, 2.82]; Placebo = 2.63 [2.44, 2.83]; p = 0.929). Logistic regression analyses showed that increased breast field separation positively correlated with increased radiation dermatitis severity (p = 0.018). In patients with high breast field separation (≥ 25 cm), RDS scores (Curcumin = 2.70 [2.21, 3.19]; HPR Plus™ = 3.57 [3.16, 4.00]; Placebo = 2.95 [2.60, 3.30]; p = 0.024) and pain scores (Curcumin = 0.52 [- 0.28, 1.33]; HPR Plus™ = 0.55 [- 0.19, 1.30]; Placebo = 1.73 [0.97, 2.50]; p = 0.046) significantly differed at the end of RT.

CONCLUSIONS

Although there were no significant effects of the treatment groups on the overall population, our exploratory subgroup analysis suggests that prophylactic treatment with topical curcumin may be effective for minimizing skin reactions and pain for patients with high breast separation (≥ 25 cm) who may have the worst skin reactions.

Extracellular Vesicles in Modifying the Effects of Ionizing Radiation

Extracellular vesicles (EVs) are membrane-coated nanovesicles actively secreted by almost all cell types. EVs can travel long distances within the body, being finally taken up by the target cells, transferring information from one cell to another, thus influencing their behavior. The cargo of EVs comprises of nucleic acids, lipids, and proteins derived from the cell of origin, thereby it is cell-type specific; moreover, it differs between diseased and normal cells. Several studies have shown that EVs have a role in tumor formation and prognosis. It was also demonstrated that ionizing radiation can alter the cargo of EVs. EVs, in turn can modulate radiation responses and they play a role in radiation-induced bystander effects. Due to their biocompatibility and selective targeting, EVs are suitable nanocarrier candidates of drugs in various diseases, including cancer. Furthermore, the cargo of EVs can be engineered, and in this way they can be designed to carry certain genes or even drugs, similar to synthetic nanoparticles. In this review, we describe the biological characteristics of EVs, focusing on the recent efforts to use EVs as nanocarriers in oncology, the effects of EVs in radiation therapy, highlighting the possibilities to use EVs as nanocarriers to modulate radiation effects in clinical applications.

Radiosensitizing Potential of Curcumin in Different Cancer Models

Over the past decades, studies of phytochemicals as modifiers of radiotherapeutic efficacy have become increasingly popular to improve the treatment outcome of human malignancies. In the current comprehensive review article, radiosensitizing effects of curcumin, a yellow-colored polyphenolic constituent of turmeric, in various preclinical cancer models, both In Vitro and In Vivo, are presented. Attenuation of radioadaptation and augmentation of irradiation-induced cancer cell killing are achieved through multifaceted action of curcumin on suppression of prosurvival and antiapoptotic factors. Most importantly, curcumin can block radiation-triggered NF-κB signaling pathway and downregulate downstream effector proteins, thereby conferring potentiation of radioresponses. Based on the elucidated molecular mechanisms but also due to its safety profile and low cost, curcumin might be considered a promising adjuvant agent to enhance radiotherapeutic efficacy in the treatment of various cancer types formed in different human organ systems. Further efforts to translate the current preclinical knowledge to the real application of curcumin in combinatorial radiotherapeutic strategies in clinical settings are necessary.AbbreviationsAKTprotein kinase BARMSalveolar rhabdomyosarcomaATMataxia telangiectasia mutatedBaxBcl-2-associated X proteinBcl-2B-cell lymphoma 2CDC2cyclin-dependent kinase 2Bcl-xLB-cell lymphoma-extra largec-FLIPcellular FLICE-like inhibitory proteinCDDPcisplatinCOX-2cyclooxygenase-2cyt ccytochrome cDNA-PKcsDNA-dependent protein kinaseEGFRepidermal growth factor receptorEMTepithelial-mesenchymal transitionERKextracellular signal-regulated kinaseESEwing`s sarcomaETS2erythroblastosis virus transcription factor 2GBMglioblastoma multiformeHCChepatocellular carcinomaHNSCChead and neck squamous cell carcinomaIAPinhibitor of apoptosis proteinIκBαinhibitor of κB alphaIKKinhibitor of κB kinaseIRionizing radiationlncRNAlong non-coding RNAlucluciferaseMcl-1myeloid cell leukemia-1MDR1multidrug resistance protein 1miRmicroRNAMMP-9matrix metalloproteinase-9mTORmammalian target of rapamycinNBneuroblastomaNF-κBnuclear factor-κBNPCnasopharyngeal carcinomaNSCLCnon-small cell lung cancerOSCCoral squamous cell carcinomaPARPpoly-(ADP-ribose)-polymerasepH2AXphosphorylated histone 2AX-immunoreactivePI3Kphosphatidylinositol 3-kinasePrp4KPre-mRNA processing factor 4 kinaseRCCrenal cell carcinomaROSreactive oxygen speciesSCCsquamous cell carcinomaSLNsolid lipid nanoparticleSOD2superoxide dismutase 2TERTtelomerase reverse transcriptaseTNF-αtumor necrosis factor-αTxnRd1thioredoxin reductase-1VEGFvascular endothelial growth factorXIAPX-linked inhibitor of apoptosis proteinΔΨmmitochondrial membrane potential.

Strategy for improved therapeutic efficiency of curcumin in the treatment of gastric cancer

Gastric cancer is a common oncological disease. Although enormous efforts have been expended, possible therapeutic modalities are still limited. For this reason, new therapeutic approaches and agents are highly requested and intensively developed. One strategy is the application of natural agents, such as curcumin, with proven anticancer effects and low toxicity for patients. Therefore, this review discusses the potential application of curcumin in the therapy of gastric cancer and its potential incorporation in therapeutic regimens. Because one of the largest impediments for widespread curcumin application is its limited bioavailability (caused mainly by its very low water solubility), studied strategies (drug delivery systems and curcumin derivatization) aimed to solve this obstacle are discussed in more detail.

Radiation-induced lung injury: latest molecular developments, therapeutic approaches, and clinical guidance

Cancer research has advanced throughout the years with respect to the personalization of the treatments and to targeting cancer-related molecular signatures on different organs. Still, the adverse events of the treatments such as radiotherapy are of high concern as they may increase the mortality rate due to their severity. With the improved efficiency of cancer treatments, patient survival has been increasing. Consequently, the number of patients with adverse effects from radiotherapy is also expected to increase in the forthcoming years. Therefore, approaches for personalized treatments include the elimination of adverse events and decreasing the toxicity in healthy tissues while increasing the efficiency of cancer cytotoxicity. In this context, this paper aims to discuss the recent advances in the field of thorax irradiation therapy and its related toxicities leading to radiation pneumonitis in cancer patients. Molecular mechanisms involved in the radiation-induced lung injury and approaches used to overcome this lung injury are discussed. The discourse covers approaches such as therapeutic administration of natural products, current and prospective radioprotective drugs, and applications of mesenchymal stem cells for radiation-induced lung injury.

Curcumin and Quercetin as Potential Radioprotectors and/or Radiosensitizers for X-ray-based Sterilization of Male Navel Orangeworm Larvae

Two natural compounds (quercetin and curcumin) were tested as sensitizing or protecting agents for Navel Orangeworm (NOW) larvae under x-ray sterilization, with the aim to reduce required doses and thus facilitate the substitution of x-ray for radioisotopes. The compounds were added to NOW diet at concentrations between 0 and 1.0 mmol kg⁻¹ and subsequent reared male larvae were subjected to x-ray irradiation (90 keV, 9 mA) to doses up to 15 Gy. Upon emergence as adults, surviving male NOW were paired with colony virgin females and placed in isolation for observation of deformity, mortality, and fertility. Treatments included rearing larvae on infused diet before irradiation, after irradiation, and both. Results were tabulated as percentage of insects that were dead/deformed, infertile, or fertile and subjected to chi-squared analysis. While insect populations subjected to quercetin treatments were not found to be significantly different from control at any x-ray dose, all curcumin treatments yielded significant differences at an absorbed dose of 10 Gy, both in terms of decreased mortality and fertility. While none of the treatments resulted in acceptable mortality/deformity rates, the observed effects strongly support the need for continued testing of natural compounds for their efficacy to reduce required dose levels for sterilization.

Radiation-Induced Reactions in The Liver - Modulation of Radiation Effects by Lifestyle-Related Factors

Radiation has a wide variety of effects on the liver. Fibrosis is a concern in medical fields as one of the acute effects of high-dose irradiation, such as with cancer radiotherapies. Cancer is also an important concern following exposure to radiation. The liver has an active metabolism and reacts to radiations. In addition, effects are modulated by many environmental factors, such as high-calorie foods or alcohol beverages. Adaptations to other environmental conditions could also influence the effects of radiation. Reactions to radiation may not be optimally regulated under conditions modulated by the environment, possibly leading to dysregulation, disease or cancer. Here, we introduce some reactions to ionizing radiation in the liver, as demonstrated primarily in animal experiments. In addition, modulation of radiation-induced effects in the liver due to factors such as obesity, alcohol drinking, or supplements derived from foods are reviewed. Perspectives on medical applications by modulations of radiation effects are also discussed.

Randomized, double-blind, placebo-controlled phase II trial of nanocurcumin in prostate cancer patients undergoing radiotherapy

Clinical potential of curcumin in radiotherapy (RT) setting is outstanding and of high interest. The main purpose of this randomized controlled trial (RCT) was to assess the beneficial role of nanocurcumin to prevent and/or mitigate radiation-induced proctitis in prostate cancer patients undergoing RT. In this parallel-group study, 64 eligible patients with prostate cancer were randomized to receive either oral nanocurcumin (120 mg/day) or placebo 3 days before and during the RT course. Acute toxicities including proctitis and cystitis were assessed weekly during the treatment and once thereafter using CTCAE v.4.03 grading criteria. Baseline-adjusted hematologic nadirs were also analyzed and compared between the two groups. The patients undergoing definitive RT were followed to evaluate the tumor response. Nanocurcumin was well tolerated. Radiation-induced proctitis was noted in 18/31 (58.1%) of the placebo-treated patients versus 15/33 (45.5%) of nanocurcumin-treated patients (p = 0.313). No significant difference was also found between the two groups with regard to radiation-induced cystitis, duration of radiation toxicities, hematologic nadirs, and tumor response. In conclusion, this RCT was underpowered to indicate the efficacy of nanocurcumin in this clinical setting but could provide a considerable new translational insight to bridge the gap between the laboratory and clinical practice.

Pharmacology of natural radioprotectors

Radiotherapy is one of the most efficient ways to treat cancer. However, deleterious effects, such as acute and chronic toxicities that reduce the quality of life, may result. Naturally occurring compounds have been shown to be non-toxic over wide dose ranges and are inexpensive and effective. Additionally, pharmacological strategies have been developed that use radioprotectors to inhibit radiation-induced toxicities. Currently available radioprotectors have several limitations, including toxicity. In this review, we present the mechanisms of proven radioprotectors, ranging from free radical scavenging (the best-known mechanism of radioprotection) to molecular-based radioprotection (e.g., upregulating expression of heat shock proteins). Finally, we discuss naturally occurring compounds with radioprotective properties in the context of these mechanisms.

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.