Ionizing radiation enhances matrix metalloproteinase-2 production in human lung epithelial cells

The clinical manifestations and molecular pathogenesis of radiation fibrosis

Advances in radiation techniques have enabled the precise delivery of higher doses of radiotherapy to tumours, while sparing surrounding healthy tissues. Consequently, the incidence of radiation toxicities has declined, and will likely continue to improve as radiotherapy further evolves. Nonetheless, ionizing radiation elicits tissue-specific toxicities that gradually develop into radiation-induced fibrosis, a common long-term side-effect of radiotherapy. Radiation fibrosis is characterized by an aberrant wound repair process, which promotes the deposition of extensive scar tissue, clinically manifesting as a loss of elasticity, tissue thickening, and organ-specific functional consequences. In addition to improving the existing technologies and guidelines directing the administration of radiotherapy, understanding the pathogenesis underlying radiation fibrosis is essential for the success of cancer treatments. This review integrates the principles for radiotherapy dosimetry to minimize off-target effects, the tissue-specific clinical manifestations, the key cellular and molecular drivers of radiation fibrosis, and emerging therapeutic opportunities for both prevention and treatment.

Predicting Radiation-Induced Lung Injury in Patients With Lung Cancer: Challenges and Opportunities

Radiation-induced lung injury (RILI) is one of the main dose-limiting toxicities in radiation therapy (RT) for lung cancer. Approximately 10% to 20% of patients show signs of RILI of variable severity. The reason for the wide range of RILI severity and the mechanisms underlying its development are only partially understood. A number of clinical risk factors have been identified that can aid in clinical decision making. Technological advancements in RT and the use of strict organ-at-risk dose constraints have helped to reduce RILI. Predicting patients at risk for RILI may be further improved with a combination of cytokine assessments, γH2AX-assays in leukocytes, or epigenetic markers. A complicating factor is the lack of an objective definition of RILI. Tools such as computed tomography densitometry, fluorodeoxyglucose-positron emission tomography uptake, changes in lung function measurements, and exhaled breath analysis can be implemented to better define and quantify RILI. This can aid in the search for new biomarkers, which can be accelerated by omics techniques, single-cell RNA sequencing, mass cytometry, and advances in patient-specific in vitro cell culture models. An objective quantification of RILI combined with these novel techniques can aid in the development of biomarkers to better predict patients at risk and allow personalized treatment decisions.

A human lung alveolus-on-a-chip model of acute radiation-induced lung injury

Acute exposure to high-dose gamma radiation due to radiological disasters or cancer radiotherapy can result in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium (Lung Alveolus Chip) is used to model acute RILI in vitro. Both lung epithelium and endothelium exhibit DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage is observed in the endothelium. The radiation dose sensitivity observed on-chip is more like the human lung than animal preclinical models. The Alveolus Chip is also used to evaluate the potential ability of two drugs - lovastatin and prednisolone - to suppress the effects of acute RILI. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative for studying the molecular basis of acute RILI and may be useful for evaluation of new radiation countermeasure therapeutics.

Repurposing FDA-approved drugs as inhibitors of therapy-induced invadopodia activity in glioblastoma cells

Glioblastoma (GBM) is the most prevalent primary central nervous system tumour in adults. The lethality of GBM lies in its highly invasive, infiltrative, and neurologically destructive nature resulting in treatment failure, tumour recurrence and death. Even with current standard of care treatment with surgery, radiotherapy and chemotherapy, surviving tumour cells invade throughout the brain. We have previously shown that this invasive phenotype is facilitated by actin-rich, membrane-based structures known as invadopodia. The formation and matrix degrading activity of invadopodia is enhanced in GBM cells that survive treatment. Drug repurposing provides a means of identifying new therapeutic applications for existing drugs without the need for discovery or development and the associated time for clinical implementation. We investigate several FDA-approved agents for their ability to act as both cytotoxic agents in reducing cell viability and as 'anti-invadopodia' agents in GBM cell lines. Based on their cytotoxicity profile, three agents were selected, bortezomib, everolimus and fludarabine, to test their effect on GBM cell invasion. All three drugs reduced radiation/temozolomide-induced invadopodia activity, in addition to reducing GBM cell viability. These drugs demonstrate efficacious properties warranting further investigation with the potential to be implemented as part of the treatment regime for GBM.

Short-term and bystander effects of radiation on murine submandibular glands

Many patients treated for head and neck cancers experience salivary gland hypofunction due to radiation damage. Understanding the mechanisms of cellular damage induced by radiation treatment is important in order to design methods of radioprotection. In addition, it is crucial to recognize the indirect effects of irradiation and the systemic responses that may alter saliva secretion. In this study, radiation was delivered to murine submandibular glands (SMGs) bilaterally, using a 137Cs gamma ray irradiator, or unilaterally, using a small-animal radiation research platform (SARRP). Analysis at 3, 24 and 48 h showed dynamic changes in mRNA and protein expression in SMGs irradiated bilaterally. Unilateral irradiation using the SARRP caused similar changes in the irradiated SMGs, as well as significant off-target, bystander effects in the non-irradiated contralateral SMGs.

Prediction of the Mechanism of Sodium Butyrate against Radiation-Induced Lung Injury in Non-Small Cell Lung Cancer Based on Network Pharmacology and Molecular Dynamic Simulations and Molecular Dynamic Simulations

Background

Radiation-induced lung injury (RILI) is a severe side effect of radiotherapy for non-small cell lung cancer (NSCLC) ,and one of the major hindrances to improve the efficacy of radiotherapy. Previous studies have confirmed that sodium butyrate (NaB) has potential of anti-radiation toxicity. However, the mechanism of the protective effect of NaB against RILI has not yet been clarified. This study aimed to explore the underlying protective mechanisms of NaB against RILI in NSCLC through network pharmacology, molecular docking, molecular dynamic simulations and in vivo experiments.

Methods

The predictive target genes of NaB were obtained from the PharmMapper database and the literature review. The involved genes of RILI and NSCLC were predicted using OMIM and GeneCards database. The intersectional genes of drug and disease were identified using the Venny tool and uploaded to the Cytoscape software to identify 5 core target genes of NaB associated with RILI. The correlations between the 5 core target genes and EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors were analyzed using TIMER 2.0, TIMER and TISIDB databases. We constructed the mechanism maps of the 3 key signaling pathways using the KEGG database based on the results of GO and KEGG analyses from Metascape database. The 5 core target genes and drug were docked using the AutoDock Vina tool and visualized using PyMOL software. GROMACS software was used to perform 100 ns molecular dynamics simulation. Irradiation-induced lung injury model in mice were established to assess the therapeutic effects of NaB.

Results

A total of 51 intersectional genes involved in NaB against RILI in NSCLC were identified. The 5 core target genes were AKT1, TP53, NOTCH1, SIRT1, and PTEN. The expressions of the 5 core target genes were significantly associated with EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors, respectively. The results from GO analysis of the 51 intersectional genes revealed that the biological processes were focused on the regulation of smooth muscle cell proliferation, oxidative stress and cell death, while the three key KEGG pathways were enriched in PI3K-Akt signal pathway, p53 signal pathway, and FOXO signal pathway. The docking of NaB with the 5 core target genes showed affinity and stability, especially AKT1. In vivo experiments showed that NaB treatment significantly protected mice from RILI, with reduced lung histological damage. In addition, NaB treatment significantly inhibited the PI3K/Akt signaling pathway.

Conclusions

NaB may protect patients from RILI in NSCLC through multiple target genes including AKT1, TP53, NOTCH1, SIRT1 and PTEN, with multiple signaling pathways involving, including PI3K-Akt pathway, p53 pathway, and FOXO pathways. Our findings effectively provide a feasible theoretical basis to further elucidate the mechanism of NaB in the treatment of RILI.

Inhibition of Matrix Metalloproteinases and Cancer Cell Detachment by Ru(II) Polypyridyl Complexes Containing 4,7-Diphenyl-1,10-phenanthroline Ligands-New Candidates for Antimetastatic Agents

Primary tumor targeting is the dominant approach in drug development, while metastasis is the leading cause of cancer death. Therefore, in addition to the cytotoxic activity of a series of Ru(II) polypyridyl complexes of the type [Ru(dip)₂L]²⁺ (dip: 4,7-diphenyl-1,10-phenanthroline while L = dip; bpy: 2,2′-bipyridine; bpy-SC: bipyridine derivative bearing a semicarbazone 2-formylopyridine moiety; dpq, dpq(CH₃)₂, dpb: quinoxaline derivatives) their ability to inhibit cell detachment was investigated. In vitro studies performed on lung cancer A549 cells showed that they accumulate in cells very well and exhibit moderate cytotoxicity with IC₅₀ ranging from 4 to 13 µM. Three of the studied compounds that have dip, bpy-SC, or dpb ligands after treatment of the cells with a non-toxic dose (<¹/₂IC₅₀) enhanced their adhesion properties demonstrated by lower detachment in the trypsin resistance assay. The same complexes inhibited both MMP-2 and MMP-9 enzyme activities with IC₅₀ ranging from 2 to 12 µM; however, the MMP-9 inhibition was stronger. More detailed studies for [Ru(dip)₂(bpy-SC)]²⁺, which induced the greatest increase in cell adhesion, revealed that it is predominately accumulated in the cytoskeletal fraction of A549 cells. Moreover, cells treated with this compound showed the localization of MMP-9 to a greater extent also in the cytoskeleton. Taken together, our results indicate the possibility of a reduction of metastatic cells escaping from the primary lesion to the surrounding tissue by prevention of their detachment and by influencing the activity of MMP-2 and MMP-9.

Shear bond strength analysis and marginal gap evaluation of restoration–tooth interface of aesthetic restorations after simulated Co-60 gamma irradiation

Background:

Radiotherapy to the head and neck region may cause considerable radiotherapy-induced changes in the surrounding tissues. These changes are oral mucositis, hyposalivation, dental caries, osteoradionecrosis, trismus and overall impact on patients’ quality of life. Tooth-coloured synthetic materials, unlike metallic restoration, did not influence radiation dose distribution. However, their exposure to a gamma radiation therapeutic dose during treatment might cause structural and compositional changes that alter their mechanical and physical properties.

Aim:

This study intends to evaluate the effect of Co 60 gamma rays on shear bond strength and marginal adaptation of already restored tooth surfaces, to help in material selection before the onset of radiotherapy.

Materials and methods:

Hundred freshly extracted human permanent mandibular molar teeth collected and stored in a 0·2% thymol solution for disinfection and were randomly divided into two groups of 50 each, to be tested for the shear bond strength of restoration to dentin and the marginal gap at tooth–restoration interface, respectively.

Results:

ANOVA showed a significant effect of both radiotherapy (F = 40·33, p < 0·001) and restorations (134·00, p < 0·001) on the marginal gap at the interface. In the without radiotherapy group, the mean marginal gap was least in Group Z250, and in with radiation, Bulk Fill has the least mean marginal gap. The mean shear bond strength was comparatively higher for all restorations without radiation than with radiation (p < 0·001).

Findings:

Gamma radiation affects the physical or mechanical properties of tooth structure and the tooth restorative interface. Composites seem to be good restorative material when placed before the onset of radiotherapy in head and neck cancer patients.

An Iatrogenic Model of Brain Small-Vessel Disease: Post-Radiation Encephalopathy

We studied 114 primitive cerebral neoplasia, that were surgically treated, and underwent radiotherapy (RT), and compared their results to those obtained by 190 patients diagnosed with subcortical vascular dementia (sVAD). Patients with any form of primitive cerebral neoplasia underwent whole-brain radiotherapy. All the tumor patients had regional field partial brain RT, which encompassed each tumor, with an average margin of 2.6 cm from the initial target tumor volume. We observed in our patients who have been exposed to a higher dose of RT (30–65 Gy) a cognitive and behavior decline similar to that observed in sVAD, with the frontal dysexecutive syndrome, apathy, and gait alterations, but with a more rapid onset and with an overwhelming effect. Multiple mechanisms are likely to be involved in radiation-induced cognitive impairment. The active site of RT brain damage is the white matter areas, particularly the internal capsule, basal ganglia, caudate, hippocampus, and subventricular zone. In all cases, radiation damage inside the brain mainly focuses on the cortical–subcortical frontal loops, which integrate and process the flow of information from the cortical areas, where executive functions are “elaborated” and prepared, towards the thalamus, subthalamus, and cerebellum, where they are continuously refined and executed. The active mechanisms that RT drives are similar to those observed in cerebral small vessel disease (SVD), leading to sVAD. The RT’s primary targets, outside the tumor mass, are the blood–brain barrier (BBB), the small vessels, and putative mechanisms that can be taken into account are oxidative stress and neuro-inflammation, strongly associated with the alteration of NMDA receptor subunit composition.

Heavy-ion beam irradiation inhibits invasion of tongue squamous cell carcinoma Tca8113 cells

Tongue squamous cell carcinoma (TSCC) is a common malignant tumor type with aggressive biological characteristics, located in the oral and maxillofacial region. Vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs) have been implicated in the invasion and metastasis of various malignant tumor types, such as lung cancer and gastric carcinoma. High linear energy transfer (LET) particle irradiation has several advantages over conventional X-rays in suppressing the invasion and metastasis of malignant tumors. The objective of the present study was to investigate the effects of high-LET carbon ions and low-LET X-rays on the expression of VEGF and MMPs, and to identify the associated mechanisms in the Tca8113 TSCC cell line. Tca8113 cells were irradiated with carbon ions or X-rays at doses of 1 and 4 Gy. An immunofluorescence assay indicated that VEGF expression was notably decreased at 24 and 48 h after heavy ion irradiation compared with irradiation with conventional X-rays. The expression of MMP-2 and MMP-9 also decreased in a dose-dependent manner following heavy ion irradiation. These findings indicate that compared with low-LET X-ray irradiation, high-LET carbon ions possess higher biological efficacy in inhibiting the invasive ability of Tca8113 cells via reduction of VEGF, MMP-2 and MMP-9 expression.

Effect of MMP-2 gene silencing on radiation-induced DNA damage in human normal dermal fibroblasts and breast cancer cells

Introduction

Diagnostic and therapeutic ionizing radiation (IR) is one of the well known long term risk factors of breast cancer. Extremely lethal consequences of IR causes double-strand breaks, which are mainly responsible for genomic instability, altered gene expression, and cell death.

Findings

This study evaluated the effect of matrix metalloproteinases-2 (MMP-2) gene silencing using MMP-2 shRNA expression plasmids (pMMP-2) on IR induced cytotoxicity and DNA damage by MTT, dead green, γH2AX and comet assays in human normal dermal fibroblasts (HDFs) and MCF-7 human breast cancer cells. IR has decreased the viability of HDFs and MCF-7 cells with increasing IR (2-10Gy). IR induced DNA damage in both HDFs and MCF-7 cells. However, pMMP-2 transfection has increased the viability of irradiated HDFs (10Gy) and significantly decreased the viability of irradiated MCF-7 cells (10Gy). Further, DNA damage in terms of γH2AX foci decreased with pMMP-2 transfection in irradiated HDFs (10Gy) and increased in irradiated MCF-7 cells (10Gy). In addition, MMP-2 gene silencing using pMMP-2 decreased comet tail length in irradiated HDFs but increased in irradiated MCF-7 cells.

Conclusions

The results conclude that pMMP-2 has protected HDFs and sensitized the MCF-7 cells from IR induced DNA damage. This differential response might be due to IR induced MMP-2 distinctive ROS generation in HDFs and MCF-7 cells.

Electronic supplementary material

The online version of this article (10.1186/s41021-019-0131-x) contains supplementary material, which is available to authorized users.

Inhibition of Radiation and Temozolomide-Induced Invadopodia Activity in Glioma Cells Using FDA-Approved Drugs

The most common primary central nervous system tumor in adults is the glioblastoma multiforme (GBM). The highly invasive nature of GBM cells is a significant factor resulting in the inevitable tumor recurrence and poor patient prognosis. Tumor cells utilize structures known as invadopodia to faciliate their invasive phenotype. In this study, utilizing an array of techniques, including gelatin matrix degradation assays, we show that GBM cell lines can form functional gelatin matrix degrading invadopodia and secrete matrix metalloproteinase 2 (MMP-2), a known invadopodia-associated matrix-degrading enzyme. Furthermore, these cellular activities were augmented in cells that survived radiotherapy and temozolomide treatment, indicating that surviving cells may possess a more invasive phenotype posttherapy. We performed a screen of FDA-approved agents not previously used for treating GBM patients with the aim of investigating their "anti-invadopodia" and cytotoxic effects in GBM cell lines and identified a number that reduced cell viability, as well as agents which also reduced invadopodia activity. Importantly, two of these, pacilitaxel and vinorelbine tartrate, reduced radiation/temozolomide-induced invadopodia activity. Our data demonstrate the value of testing previously approved drugs (repurposing) as potential adjuvant agents for the treatment of GBM patients to reduce invadopodia activity, inhibit GBM cell invasion, and potentially improve patient outcome.

Ilomastat, a synthetic inhibitor of MMPs, prevents lung injury induced by γ-ray irradiation in mice

Lung injury is one of the pathological features in human or animal after radiation and the main side effect for patient after lung cancer radiotherapy. The efficient protective strategy still needs to exploit and the underlying mechanisms remain to be investigated. We found that the expression and activity of matrix metalloproteinases (MMPs) significantly increased at the early stage of radiation-induced lung injury (RILI). Pretreatment with Ilomastat, a synthetic inhibitor of MMPs, decreased the expression and activity of MMPs and significantly alleviated the lung inflammation and fibrosis in the irradiated mice, as well as enhanced the survival of irradiated mice. In addition, the levels of TGF-β, IL-6, TNF-α and IL-1β in the tissues dramatically reduced in the irradiated mice pretreated with Ilomastat. Furthermore, our experiments in vitro also showed that radiation significantly increased the MMPs activity, and Ilomastat pretreatment inhibited the activity of MMPs activated by irradiation and increased the cell survival. It is the first report, to our knowledge, to demonstrate that Ilomastat is a potential effective reliever for RILI and MMPs may play important roles in the process of RILI.

Immunological Aspect of Radiation-Induced Pneumonitis, Current Treatment Strategies, and Future Prospects

Delivery of high doses of radiation to thoracic region, particularly with non-small cell lung cancer patients, becomes difficult due to subsequent complications arising in the lungs of the patient. Radiation-induced pneumonitis is an early event evident in most radiation exposed patients observed within 2-4 months of treatment and leading to fibrosis later. Several cytokines and inflammatory molecules interplay in the vicinity of the tissue developing radiation injury leading to pneumonitis and fibrosis. While certain cytokines may be exploited as biomarkers, they also appear to be a potent target of intervention at transcriptional level. Initiation and progression of pneumonitis and fibrosis thus are dynamic processes arising after few months to year after irradiation of the lung tissue. Currently, available treatment strategies are challenged by the major dose limiting complications that curtails success of the treatment as well as well being of the patient's future life. Several approaches have been in practice while many other are still being explored to overcome such complications. The current review gives a brief account of the immunological aspects, existing management practices, and suggests possible futuristic approaches.

PARP-1 depletion in combination with carbon ion exposure significantly reduces MMPs activity and overall increases TIMPs expression in cultured HeLa cells

Background

Hadron therapy is an innovative technique where cancer cells are precisely killed leaving surrounding healthy cells least affected by high linear energy transfer (LET) radiation like carbon ion beam. Anti-metastatic effect of carbon ion exposure attracts investigators into the field of hadron biology, although details remain poor. Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors are well-known radiosensitizer and several PARP-1 inhibitors are in clinical trial. Our previous studies showed that PARP-1 depletion makes the cells more radiosensitive towards carbon ion than gamma. The purpose of the present study was to investigate combining effects of PARP-1 inhibition with carbon ion exposure to control metastatic properties in HeLa cells.

Methods

Activities of matrix metalloproteinases-2, 9 (MMP-2, MMP-9) were measured using the gelatin zymography after 85 MeV carbon ion exposure or gamma irradiation (0- 4 Gy) to compare metastatic potential between PARP-1 knock down (HsiI) and control cells (H-vector - HeLa transfected with vector without shRNA construct). Expression of MMP-2, MMP-9, tissue inhibitor of MMPs such as TIMP-1, TIMP-2 and TIMP-3 were checked by immunofluorescence and western blot. Cell death by trypan blue, apoptosis and autophagy induction were studied after carbon ion exposure in each cell-type. The data was analyzed using one way ANOVA and 2-tailed paired-samples T-test.

Results

PARP-1 silencing significantly reduced MMP-2 and MMP-9 activities and carbon ion exposure further diminished their activities to less than 3 % of control H-vector. On the contrary, gamma radiation enhanced both MMP-2 and MMP-9 activities in H-vector but not in HsiI cells. The expression of MMP-2 and MMP-9 in H-vector and HsiI showed different pattern after carbon ion exposure. All three TIMPs were increased in HsiI, whereas only TIMP-1 was up-regulated in H-vector after irradiation. Notably, the expressions of all TIMPs were significantly higher in HsiI than H-vector at 4 Gy. Apoptosis was the predominant mode of cell death and no autophagic death was observed.

Conclusions

Our study demonstrates for the first time that PARP-1 inhibition in combination with carbon ion synergistically decreases MMPs activity along with overall increase of TIMPs. These data open up the possibilities of improvement of carbon ion therapy with PARP-1 inhibition to control highly metastatic cancers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-016-0703-x) contains supplementary material, which is available to authorized users.

Sublethal dose of irradiation enhances invasion of malignant glioma cells through p53-MMP 2 pathway in U87MG mouse brain tumor model

Background

Glioblastoma is a highly lethal neoplasm that frequently recurs locally after radiotherapy, and most of these recurrences originate from near the irradiated target field. In the present study, we identified the effects of radiation on glioma invasion and p53, TIMP-2, and MMP-2 expression through in vitro and in vivo experiments.

Methods

The U87MG (wt p53) and U251 (mt p53) human malignant glioma cell lines were prepared, and the U2OS (wt 53) and Saos2 (del p53) osteosarcoma cell lines were used as p53 positive and negative controls. The four cell lines and p53 knock-downed U87MG cells received radiation (2–6 Gy) and were analyzed for expression of p53 and TIMP-2 by Western blot, and MMP-2 activity was detected by zymography. In addition, the effects of irradiation on directional invasion of malignant glioma were evaluated by implanting nude mice with bioluminescent u87-Fluc in vivo followed by MMP-2, p53, and TIMP-2 immunohisto-chemistry and in situ zymography.

Results

MMP-2 activity and p53 expression increased in proportional to the radiation dose in cell lines with wt p53, but not in the cell lines with del or mt p53. TIMP-2 expression did not increase in U87MG cells. MMP-2 activity decreased in p53 knock-downed U87MG cells but increased in the control group. Furthermore, radiation enhanced MMP-2 activity and increased tumor margin invasiveness in vivo. Tumor cells invaded by radiation overexpressed MMP-2 and p53 and revealed high gelatinolytic activity compared with those of non-radiated tumor cells.

Conclusion

Radiation-induced upregulation of p53 modulated MMP-2 activity, and the imbalance between MMP-2 and TIMP-2 may have an important role in glioblastoma invasion by degrading the extracellular matrix. Bioluminescent “U87-Fluc”was useful for observing tumor formation without sacrifice after implanting tumor cells in the mouse brain. These findings suggest that the radiotherapy involved field for malignant glioma needs to be reconsidered, and that future trials should investigate concurrent pharmacologic therapies that inhibit invasion associated with radiotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0475-8) contains supplementary material, which is available to authorized users.

Effect of 15-hydroxyprostaglandin dehydrogenase inhibitor on wound healing

PGE2 is an important mediator of wound healing. It is degraded and inactivated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Various growth factors, type IV collagen, TIMP-2 and PGE2 are important mediators of inflammation involving wound healing. Overproduction of TGF-β and suppression of PGE2 are found in excessive wound scarring. If we make the condition downregulating growth factors and upregulating PGE2, the wound will have a positive effect which results in little scar formation after healing. TD88 is a 15-PGDH inhibitor based on thiazolinedione structure. We evaluated the effect of TD88 on wound healing. In 10 guinea pigs (4 control and 6 experimental groups), we made four 1cm diameter-sized circular skin defects on each back. TD88 and vehicle were applicated on the wound twice a day for 4 days in the experimental and control groups, respectively. Tissue samples were harvested for qPCR and histomorphometric analyses on the 2nd and 4th day after treatment. Histomorphometric analysis showed significant reepithelization in the experimental group. qPCR analysis showed significant decrease of PDGF, CTGF and TIMP-2, but significant increase of type IV collagen in the experimental group. Taken together TD88 could be a good effector on wound healing, especially in the aspects of prevention of scarring.

Radiotherapy effect on nano-mechanical properties and chemical composition of enamel and dentine

OBJECTIVE

To understand radiotherapy-induced dental lesions characterized by enamel loss or delamination near the dentine-enamel junction (DEJ), this study evaluated enamel and dentine nano-mechanical properties and chemical composition before and after simulated oral cancer radiotherapy.

DESIGN

Sections from seven non-carious third molars were exposed to 2 Gy fractions, 5 days/week for 7 weeks for a total of 70 Gy. Nanoindentation was used to evaluate Young's modulus, while Raman microspectroscopy was used to measure protein/mineral ratios, carbonate/phosphate ratios, and phosphate peak width. All measures were completed prior to and following radiation at the same four buccal and lingual sites 500 and 30 μm from the DEJ in enamel and dentine (E-500, E-30, D-30 and D-500).

RESULTS

The elastic modulus of enamel and dentine was significantly increased (P ≤ 0.05) following radiation. Based on Raman spectroscopic analysis, there was a significant decrease in the protein to mineral ratio (2931/430 cm(-1)) following radiation at all sites tested except at D-500, while the carbonate to phosphate ratio (1070/960 cm(-1)) increased at E-30 and decreased at D-500. Finally, phosphate peak width as measured by FWHM at 960 cm(-1) significantly decreased at both D-30 and D-500 following radiation.

CONCLUSIONS

Simulated radiotherapy produced an increase in the stiffness of enamel and dentine near the DEJ. Increased stiffness is speculated to be the result of the radiation-induced decrease in the protein content, with the percent reduction much greater in the enamel sites. Such changes in mechanical properties and chemical composition could potentially contribute to DEJ biomechanical failure leading to enamel delamination that occurs post-radiotherapy. However, other analyses are required for a better understanding of radiotherapy-induced effects on tooth structure to improve preventive and restorative treatments for oral cancer patients.

HAb18G/CD147 promotes radioresistance in hepatocellular carcinoma cells: a potential role for integrin β1 signaling

Radiotherapy has played a limited role in the treatment of hepatocellular carcinoma (HCC) due to the risk of tumor radioresistance. A previous study in our laboratory confirmed that CD147 interacts with integrin β1 and plays an important role in modulating the malignant properties of HCC cells. In this study, we further evaluated the role of CD147 in the radioresistance of HCC and as a potential target for improving radiosensitivity. Upon irradiation, the colony formation, apoptosis, cell-cycle distribution, migration, and invasion of SMMC-7721, CD147-knockout SMMC-7721, HepG2, and CD147-knockdown HepG2 cells were determined. A nude mouse xenograft model and a metastatic model of HCC were used to detect the role of CD147 in radioresistance in vivo. Deletion of HAb18G/CD147 significantly enhanced the radiosensitivity of SMMC-7721 and HepG2 cells, and knocking out HAb18G/CD147 in SMMC-7721 cells attenuated irradiation-enhanced migration and invasion. The knockout and antibody blockade of CD147 decreased the tumor growth and metastatic potentials of HCC cells under irradiation. CD147-deleted SMMC-7721 cells showed diminished levels of calpain, cleaved talin, active integrin β1, and decreased p-FAK (Tyr397) and p-Akt (Ser473) levels. FAK and PI3K inhibitors, as well as integrin β1 antibodies, increased the radiation-induced apoptosis of SMMC-7721 cells. Our data provide evidence for CD147 as an important determinant of radioresistance via the regulation of integrin β1 signaling. Inhibition of the HAb18G/CD147 integrin interaction may improve the efficiency of radiosensitivity and provide a potential new approach for HCC therapy.

Dose-dependent hepatic transcriptional responses in Atlantic salmon (Salmo salar) exposed to sublethal doses of gamma radiation

Due to the production of free radicals, gamma radiation may pose a hazard to living organisms. The high-dose radiation effects have been extensively studied, whereas the ecotoxicity data on low-dose gamma radiation is still limited. The present study was therefore performed using Atlantic salmon (Salmo salar) to characterize effects of low-dose (15, 70 and 280 mGy) gamma radiation after short-term (48h) exposure. Global transcriptional changes were studied using a combination of high-density oligonucleotide microarrays and quantitative real-time reverse transcription polymerase chain reaction (qPCR). Differentially expressed genes (DEGs; in this article the phrase gene expression is taken as a synonym of gene transcription, although it is acknowledged that gene expression can also be regulated, e.g., at protein stability and translational level) were determined and linked to their biological meanings predicted using both Gene Ontology (GO) and mammalian ortholog-based functional analyses. The plasma glucose level was also measured as a general stress biomarker at the organism level. Results from the microarray analysis revealed a dose-dependent pattern of global transcriptional responses, with 222, 495 and 909 DEGs regulated by 15, 70 and 280 mGy gamma radiation, respectively. Among these DEGs, only 34 were commonly regulated by all radiation doses, whereas the majority of differences were dose-specific. No GO functions were identified at low or medium doses, but repression of DEGs associated with GO functions such as DNA replication, cell cycle regulation and response to reactive oxygen species (ROS) were observed after 280mGy gamma exposure. Ortholog-based toxicity pathway analysis further showed that 15mGy radiation affected DEGs associated with cellular signaling and immune response; 70mGy radiation affected cell cycle regulation and DNA damage repair, cellular energy production; and 280mGy radiation affected pathways related to cell cycle regulation and DNA repair, mitochondrial dysfunction and immune functions. Twelve genes representative of key pathways found in this study were verified by qPCR. Potential common MoAs of low-dose gamma radiation may include induction of oxidative stress, DNA damage and disturbance of oxidative phosphorylation (OXPHOS). Although common MoAs were proposed, a number of DEGs and pathways were still found to be dose-specific, potentially indicating multiple mechanisms of action (MOAs) of low-dose gamma radiation in fish. In addition, plasma glucose displayed an apparent increase with increasing radiation doses, although the results were not significantly different from the control. These findings suggested that sublethal doses of gamma radiation may cause dose-dependent transcriptional changes in the liver of Atlantic salmon after short-term exposure. The current study predicted multiple MoA for gamma radiation and may aid future impact assessment of environmental radioactivity in fish.

Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy.

Radiation enhances the invasiveness of irradiated and nonirradiated bystander hepatoma cells through a VEGF-MMP2 pathway initiated by p53

Recent evidence has shown that irradiation can promote the invasiveness of hepatocellular carcinoma cells and have an impact on the invasive behavior of nonirradiated surrounding cancer cells, which may enhance overall tumor aggressiveness. However, the role of the TP53 tumor suppressor gene in the invasion of irradiated hepatoma cells and their nonirradiated bystanders remain largely unknown. In the present study, we found that irradiation increased the invasiveness of human hepatoma HepG2 cells, and pretreatment of the cells with SU1498 (an inhibitor of vascular endothelial growth factor receptor 2, VEGFR2) and GM6001 (an inhibitor of matrix metalloproteinases 2, MMP2) demonstrated that radiation-enhanced invasiveness is associated with the interplay between MMP2 and VEGF signaling. In addition, while radiation-induced expression and phosphorylation of p53, inhibition of p53 function with pifithrin-α or transfection of cells with p53 siRNA significantly reduced the activation of both MMP2 and VEGF and resulted in a reduction of radiation-induced invasiveness. Interestingly, we also found that the invasiveness of the nonirradiated bystander cells was also elevated after co-culturing with irradiated cells and that bystander invasive potential was regulated paracrine in a manner by MMP2 and VEGF from the irradiated cells through a p53-dependent mechanism. Taken together, our data demonstrate that radiation-induced up-regulation of p53 is responsible for the promotion of VEGF-MMP2 pathway involved in the enhancement of invasiveness of both irradiated and bystander hepatoma cells.

Whole brain radiation-induced cognitive impairment: pathophysiological mechanisms and therapeutic targets

Radiation therapy, the most commonly used for the treatment of brain tumors, has been shown to be of major significance in tu-mor control and survival rate of brain tumor patients. About 200,000 patients with brain tumor are treated with either partial large field or whole brain radiation every year in the United States. The use of radiation therapy for treatment of brain tumors, however, may lead to devastating functional deficits in brain several months to years after treatment. In particular, whole brain radiation therapy results in a significant reduction in learning and memory in brain tumor patients as long-term consequences of treatment. Although a number of in vitro and in vivo studies have demonstrated the pathogenesis of radiation-mediated brain injury, the cel-lular and molecular mechanisms by which radiation induces damage to normal tissue in brain remain largely unknown. Therefore, this review focuses on the pathophysiological mechanisms of whole brain radiation-induced cognitive impairment and the iden-tification of novel therapeutic targets. Specifically, we review the current knowledge about the effects of whole brain radiation on pro-oxidative and pro-inflammatory pathways, matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) system and extracellular matrix (ECM), and physiological angiogenesis in brain. These studies may provide a foundation for defin-ing a new cellular and molecular basis related to the etiology of cognitive impairment that occurs among patients in response to whole brain radiation therapy. It may also lead to new opportunities for therapeutic interventions for brain tumor patients who are undergoing whole brain radiation therapy.

Sivelestat sodium hydrate reduces radiation-induced lung injury in mice by inhibiting neutrophil elastase

The aim of this study was to investigate whether sivelestat, a neutrophil elastase (NE) inhibitor, mitigates radiation-induced lung injury in mice. C57BL/6J mice were administered a dose of 20 Gy to the bilateral whole lungs. Sivelestat was administered immediately before and 1 h after irradiation in group RE2, and immediately before and 1, 3 and 6 h after irradiation in group RE4. Group R received irradiation without sivelestat injection. Mice that did not receive sivelestat injection or irradiation were used as controls. NE activity was measured 24 and 48 h after irradiation, and the mice were sacrificed 24 h, 48 h and 15 weeks after irradiation for histopathological examination. In groups RE2 and RE4, NE activity was significantly suppressed until 48 h after irradiation compared to group R. The degree of lung damage in each group was scored during histopathological examination. Results showed that the scores of groups RE2 and RE4 were significantly lower compared to those of group R 15 weeks after irradiation. In conclusion, sivelestat reduced radiation‑induced lung injury in the mice by suppressing NE activity and excessive inflammatory reactions.

Irradiation alters MMP-2/TIMP-2 system and collagen type IV degradation in brain

PURPOSE

Blood-brain barrier (BBB) disruption is one of the major consequences of radiation-induced normal tissue injury in the central nervous system. We examined the effects of whole-brain irradiation on matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) and extracellular matrix (ECM) degradation in the brain.

METHODS AND MATERIALS

Animals received either whole-brain irradiation (a single dose of 10 Gy γ-rays or a fractionated dose of 40 Gy γ-rays, total) or sham-irradiation and were maintained for 4, 8, and 24 h following irradiation. mRNA expression levels of MMPs and TIMPs in the brain were analyzed by real-time reverse transcriptase-polymerase chain reaction (PCR). The functional activity of MMPs was measured by in situ zymography, and degradation of ECM was visualized by collagen type IV immunofluorescent staining.

RESULTS

A significant increase in mRNA expression levels of MMP-2, MMP-9, and TIMP-1 was observed in irradiated brains compared to that in sham-irradiated controls. In situ zymography revealed a strong gelatinolytic activity in the brain 24 h postirradiation, and the enhanced gelatinolytic activity mediated by irradiation was significantly attenuated in the presence of anti-MMP-2 antibody. A significant reduction in collagen type IV immunoreactivity was also detected in the brain at 24 h after irradiation. In contrast, the levels of collagen type IV were not significantly changed at 4 and 8 h after irradiation compared with the sham-irradiated controls.

CONCLUSIONS

The present study demonstrates for the first time that radiation induces an imbalance between MMP-2 and TIMP-2 levels and suggests that degradation of collagen type IV, a major ECM component of BBB basement membrane, may have a role in the pathogenesis of brain injury.

Laminin 332 deposition is diminished in irradiated skin in an animal model of combined radiation and wound skin injury

Skin exposure to ionizing radiation affects the normal wound healing process and greatly impacts the prognosis of affected individuals. We investigated the effect of ionizing radiation on wound healing in a rat model of combined radiation and wound skin injury. Using a soft X-ray beam, a single dose of ionizing radiation (10-40 Gy) was delivered to the skin without significant exposure to internal organs. At 1 h postirradiation, two skin wounds were made on the back of each rat. Control and experimental animals were euthanized at 3, 7, 14, 21 and 30 days postirradiation. The wound areas were measured, and tissue samples were evaluated for laminin 332 and matrix metalloproteinase (MMP) 2 expression. Our results clearly demonstrate that radiation exposure significantly delayed wound healing in a dose-related manner. Evaluation of irradiated and wounded skin showed decreased deposition of laminin 332 protein in the epidermal basement membrane together with an elevated expression of all three laminin 332 genes within 3 days postirradiation. The elevated laminin 332 gene expression was paralleled by an elevated gene and protein expression of MMP2, suggesting that the reduced amount of laminin 332 in irradiated skin is due to an imbalance between laminin 332 secretion and its accelerated processing by elevated tissue metalloproteinases. Western blot analysis of cultured rat keratinocytes showed decreased laminin 332 deposition by irradiated cells, and incubation of irradiated keratinocytes with MMP inhibitor significantly increased the amount of deposited laminin 332. Furthermore, irradiated keratinocytes exhibited a longer time to close an artificial wound, and this delay was partially corrected by seeding keratinocytes on laminin 332-coated plates. These data strongly suggest that laminin 332 deposition is inhibited by ionizing radiation and, in combination with slower keratinocyte migration, can contribute to the delayed wound healing of irradiated skin.

Impact of Radiotherapy Dose on Dentition Breakdown in Head and Neck Cancer Patients

PURPOSE: To evaluate the severity of post-radiation dental lesions and possible correlation with radiation dose to the teeth in patients treated for head and neck cancers. METHODS AND MATERIALS: Data from 93 head and neck radiotherapy patients treated between 1997 and 2008 were analyzed retrospectively. The main effect, radiation dose to the individual teeth, was evaluated with covariates of elapsed time after radiation, xerostomia, topical fluoride use, and oral hygiene status included. Patients' radiotherapy plans were used to calculate cumulative exposure for each tooth. Patients' teeth were evaluated using a validated index and then categorized as having none/slight or moderate/severe post-radiation damage. RESULTS: Patients (31 females, 62 males) ranged in age from 18-82 yrs (mean=57). The number of teeth/patient ranged from 3-30 (mean=20) with a total of 1873 teeth evaluated. Overall, 51% of teeth had moderate/severe damage, with the remaining having little or none. Using odds ratios and 95% confidence intervals, the odds for moderate/severe damage were 2-3x greater for teeth exposed to between 30-60 Gy as compared to no radiation. However, for teeth exposed to ≥60 Gy as compared to no radiation the odds of moderate/severe tooth damage was greater by a magnitude of 10 times. CONCLUSIONS: The results indicate that there is minimal tooth damage below 30 Gy (salivary gland threshold), a greater than 1:1 increased dose-response between 30-60y likely related to salivary gland damage, and a critical threshold of ≥60Gy which may be linked to direct effects of radiation on tooth structure. These findings suggest that care should be taken during the treatment planning process to limit tooth dose, and when clinically possible to limit tooth dose to less than 60 Gy.

MMP-2 siRNA inhibits radiation-enhanced invasiveness in glioma cells

Background

Our previous work and that of others strongly suggests a relationship between the infiltrative phenotype of gliomas and the expression of MMP-2. Radiation therapy, which represents one of the mainstays of glioma treatment, is known to increase cell invasion by inducing MMP-2. Thus, inhibition of MMP-2 provides a potential means for improving the efficacy of radiotherapy for malignant glioma.

Methodology/Principal Findings

We have tested the ability of a plasmid vector-mediated MMP-2 siRNA (p-MMP-2) to modulate ionizing radiation-induced invasive phenotype in the human glioma cell lines U251 and U87. Cells that were transfected with p-MMP-2 with and without radiation showed a marked reduction of MMP-2 compared to controls and pSV-transfected cells. A significant reduction of proliferation, migration, invasion and angiogenesis of cells transfected with p-MMP-2 and in combination with radiation was observed compared to controls. Western blot analysis revealed that radiation-enhanced levels of VEGF, VEGFR-2, pVEGFR-2, p-FAK, and p-p38 were inhibited with p-MMP-2-transfected cells. TUNEL staining showed that radiation did not induce apoptosis in U87 and U251 cells while a significant increase in TUNEL-positive cells was observed when irradiated cells were simultaneously transfected with p-MMP-2 as compared to controls. Intracranial tumor growth was predominantly inhibited in the animals treated with p-MMP-2 alone or in combination with radiation compared to controls.

Conclusion/Significance

MMP-2 inhibition, mediated by p-MMP-2 and in combination with radiation, significantly reduced tumor cell migration, invasion, angiogenesis and tumor growth by modulating several important downstream signaling molecules and directing cells towards apoptosis. Taken together, our results demonstrate the efficacy of p-MMP-2 in inhibiting radiation-enhanced tumor invasion and progression and suggest that it may act as a potent adjuvant for radiotherapy in glioma patients.

Carbon ion irradiation suppresses metastatic potential of human non-small cell lung cancer A549 cells through the phosphatidylinositol-3-kinase/Akt signaling pathway

We previously showed that carbon ion irradiation can inhibit the expression of the anillin (ANLN) gene, which is regulated by the activation of the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway associated with metastasis. The purpose of this study is to compare the effects of carbon ion irradiation on the PI3K/Akt signaling pathway to those of photon irradiation. Our study showed that carbon ion irradiation of human lung adenocarcinoma cells A549 decreased their invasion more effectively than photon irradiation did. We found that carbon ion irradiation reduced the nuclear localization of ANLN at lower dose, but did not affect its expression. Low-dose carbon ion irradiation also reduced the level of phosphorylated Akt compared to untreated controls, whereas photon irradiation did not. These results suggest that carbon ion irradiation effectively suppresses the metastatic potential of A549 cells by suppressing the PI3K/Akt signaling pathway.

Spaceflight modulates expression of extracellular matrix, adhesion, and profibrotic molecules in mouse lung

NASA has reported pulmonary abnormalities in astronauts on space missions, but the molecular changes in lung tissue remain unknown. The goal of the present study was to explore the effects of spaceflight on expression of extracellular matrix (ECM), cell adhesion, and pro-fibrotic molecules in lungs of mice flown on Space Shuttle Endeavour (STS-118). C57BL/6Ntac mice housed in animal enclosure modules during a 13-day mission in space (FLT) were killed within hours after return; ground controls were treated similarly for comparison (GRD). Analysis of genes associated with ECM and adhesion molecules was performed according to quantitative RT-PCR. The data revealed that FLT lung samples had statistically significant transcriptional changes, i.e., at least 1.5-fold, in 25 out of 84 examined genes (P < 0.05); 15 genes were upregulated and 10 were downregulated. The genes that were upregulated by more than twofold were Ctgf, Mmp2, Ncam1, Sparc, Spock1, and Timp3, whereas the most downregulated genes were Lama1, Mmp3, Mmp7, vcam-1, and Sele. Histology showed profibrosis-like changes occurred in FLT mice, more abundant collagen accumulation around blood vessels, and thicker walls compared with lung samples from GRD mice. Immunohistochemistry was used to compare expression of six selected proteins associated with fibrosis. Immunoreactivity of four proteins (MMP-2, CTGF, TGF-beta1, and NCAM) was enhanced by spaceflight, whereas, no difference was detected in expression of MMP-7 and MMP-9 proteins between the FLT and GRD groups. Taken together, the data demonstrate that significant changes can be readily detected shortly after return from spaceflight in the expression of factors that can adversely influence lung function.

Response of extracellular matrix regulators in mouse lung after exposure to photons, protons and simulated solar particle event protons

This study compared the effects of photons (gamma rays), protons and simulated solar particle event protons (sSPE) on the expression of profibrotic factors/extracellular matrix (ECM) regulators in lung tissue after whole-body irradiation. TGF-beta1, matrix metalloproteinase 2 and 9 (MMP-2, -9), and tissue inhibitor of metalloproteinase 1 and 2 (TIMP-1, -2) were assessed on days 4 and 21 in lungs from C57BL/6 mice exposed to 0 Gy or 2 Gy photons (0.7 Gy/min), protons (0.9 Gy/min) and sSPE (0.056 Gy/h). RT-PCR, histological and immunohistochemical techniques were used. The most striking changes included (1) up-regulation of TGF-beta1 by photons and sSPE, but not protons, at both times, (2) MMP-2 enhancement by photons and sSPEs, (3) TIMP-1 up-regulation by photons at both times, and (4) more collagen accumulation after exposure to either photons or sSPE than after exposure to protons. The findings demonstrate that expression of important ECM regulators was highly dependent upon the radiation regimen as well as the time after exposure. The data further suggest that irradiation during an SPE may increase an astronaut's risk for pulmonary complications. The greater perturbations after photon exposure compared to proton exposure have clinical implications and warrant further investigation.

Periocular triamcinolone for prevention of macular edema after plaque radiotherapy of uveal melanoma: a randomized controlled trial

OBJECTIVE

To determine the efficacy and safety of periocular triamcinolone acetonide (40 mg) for the prevention of macular edema in patients undergoing plaque radiotherapy for uveal melanoma.

DESIGN

Prospective, randomized, controlled clinical trial.

PARTICIPANTS AND CONTROLS

One-hundred sixty-three patients with newly diagnosed uveal melanoma undergoing iodine 125 plaque radiotherapy were entered into the study. Fifty-five patients were randomized to the control group and 108 to the triamcinolone group. Eighteen-month data were available for 143 (88%) of the 163 patients.

INTERVENTION

Periocular injection of triamcinolone acetonide (40 mg in 1 ml) at the time of plaque radiotherapy and 4 months and 8 months later. Optical coherence tomography was performed at each patient evaluation.

MAIN OUTCOME MEASURES

Optical coherence tomography-evident macular edema, moderate vision loss, and poor final visual acuity.

RESULTS

Optical coherence tomography-evident macular edema occurred significantly less often in the triamcinolone group compared with the control group up to 18 months after plaque radiotherapy (hazard estimate, 0.45; 95% confidence interval, 0.19-0.70; P = 0.001). At the 18-month follow-up, moderate vision loss (loss of 3 lines or more of best-corrected visual acuity [BCVA]) and severe vision loss (BCVA <5/200 Snellen) occurred significantly less frequently in the triamcinolone group than in the control group (31% vs. 48% [P = 0.039] and 5% vs. 15% [P = 0.048], respectively). Rates of elevated intraocular pressure and cataract progression were similar in both groups.

CONCLUSIONS

Periocular triamcinolone is beneficial in reducing the risk of macular edema up to 18 months after plaque radiotherapy for uveal melanoma and significantly reduces the risk of moderate vision loss and poor visual acuity in these patients.

Inhibition of matrix metalloproteinase-2 enhances radiosensitivity by abrogating radiation-induced FoxM1-mediated G2/M arrest in A549 lung cancer cells

Matrix metalloproteinase-2 (MMP-2), is known to degrade the collagen IV, plays a role in radiation-induced lung injury. We therefore investigated the antitumor effects of combining MMP-2 inhibition using an adenovirus expressing siRNA against MMP-2 (Ad-MMP-2-Si) with radiation therapy (IR) on A549 lung cancer cells in vitro and in vivo. IR increased MMP-2 mRNA, protein and activity in lung cancer cells. MMP-2 inhibition along with IR enhanced radiosensitivity as determined by clonogenic assay, flow cytometry and TUNEL assay. We show that MMP-2 inhibition prior to irradiation reduced p53 phosphorylation, with a corresponding reduction in the expression of the p53 downstream target gene p21(Cip1/Waf1). Irradiated tumor cells induced the FoxM1-mediated DNA repair gene, XRCC1 and Checkpoint kinases 2/1, which were abrogated with combined treatment of Ad-MMP-2-Si and IR. Further, the combination of Ad-MMP-2-Si with radiotherapy significantly increased antitumor efficacy in vivo compared to either agent alone. Indeed, histological analysis of tumor sections collected from the combination group revealed more apoptotic cells. These studies suggest that MMP-2 inhibition in combination with radiotherapy abrogates G2 cell cycle arrest leading to apoptosis and provide evidence of the antitumor efficacy of combining MMP-2 inhibition with irradiation as a new therapeutic strategy for the effective treatment of NSCLC patients.

Irradiation enhances the metastatic potential of prostatic small cell carcinoma xenografts

BACKGROUND

Small cell carcinoma of the prostate (SCCP) is a rare subset of prostate cancer (0.5-2% of all prostatic carcinomas), predominantly composed of neuroendocrine (NE) cells, with a very poor prognosis. Irradiation is one of the mainstay options for SCCP local treatment, yet, little is known about the clinical response of these aggressive tumors to radiotherapy.

METHODS

Using SCID mice, the response to fractionated ionizing radiation (IR) of two unique human NE xenografts of SCCP (WISH-PC2 and WM-4A) was investigated.

RESULTS

Fractionated irradiation of WISH-PC2 xenografts using total doses of >24 Gy induced a delay in tumor growth, while total doses of >36 Gy led to local tumor eradication. However, most of the irradiated mice suffered from disseminated metastases. Similarly, in the WM-4A xenograft, a total dose of 20 Gy led to tumor growth delay and some of the mice also developed metastases. Non-irradiated local xenografts failed to disseminate, even following surgical excision of the main tumor mass; however, tumor cells administered intravenously did form metastases. Metastases of both xenografts were located in the adrenal/kidney and inter-scapular regions, areas rich in brown adipose tissue. A correlation was found between the appearance of irradiation-induced metastases and activation of the gelatinase activity of matrix metalloproteinase-9.

CONCLUSIONS

Clinically, this study raises the possibility that radiation to SCCP may promote metastatic disease. For patients in whom prostate biopsy shows a predominance of small cell cancer, it may be necessary to deliver systemic therapy together with the radiotherapy in order to prevent the development of metastases.

Ionizing radiation enhances matrix metalloproteinase-2 secretion and invasion of glioma cells through Src/epidermal growth factor receptor-mediated p38/Akt and phosphatidylinositol 3-kinase/Akt signaling pathways

Glioblastoma is a severe type of primary brain tumor, and its highly invasive character is considered to be a major therapeutic obstacle. Several recent studies have reported that ionizing radiation (IR) enhances the invasion of tumor cells, but the mechanisms for this effect are not well understood. In this study, we investigated the possible signaling mechanisms involved in IR-induced invasion of glioma cells. IR increased the matrix metalloproteinase (MMP)-2 promoter activity, mRNA transcription, and protein secretion along with the invasiveness of glioma cells lacking functional PTEN (U87, U251, U373, and C6) but not those harboring wild-type (WT)-PTEN (LN18 and LN428). IR activated phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin, and blockade of these kinases by specific inhibitors (LY294002, Akt inhibitor IV, and rapamycin, respectively) and transfection of dominant-negative (DN) mutants (DN-p85 and DN-Akt) or WT-PTEN suppressed the IR-induced MMP-2 secretion in U251 and U373 cells. In addition, inhibitors of epidermal growth factor receptor (EGFR; AG490 and AG1478), Src (PP2), and p38 (SB203580), EGFR neutralizing antibody, and transfection of DN-Src and DN-p38 significantly blocked IR-induced Akt phosphorylation and MMP-2 secretion. IR-induced activation of EGFR was suppressed by PP2, whereas LY294002 and SB203580 did not affect the activations of p38 and PI3K, respectively. Finally, these kinase inhibitors significantly reduced the IR-induced invasiveness of these cells on Matrigel. Taken together, our findings suggest that IR induces Src-dependent EGFR activation, which triggers the p38/Akt and PI3K/Akt signaling pathways, leading to increased MMP-2 expression and heightened invasiveness of PTEN mutant glioma cells.

Modifications of the radiosensitivity of a renal cancer cell line as a consequence of stable TIMP-1 overexpression

PURPOSE

To investigate the potential effects of stable tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) overexpression on DNA damage and cell killing following low-dose gamma-radiation and whether this up-regulation interfered with the activation of the matrix metalloproteinase -2 (MMP-2) and -9 (MMP-9) in a highly metastatic renal carcinoma cell line.

MATERIALS AND METHODS

Stable transfections were carried out using the cytomegalovirus expression plasmid pRc/CMV carrying TIMP-1 cDNA and LIPOFECTAMINE reagent. TIMP-1 expression in selected clones was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. Exponentially growing Caki-1 cells were treated with sub lethal doses of ionizing radiation (0- 10Gy) either alone or following stable TIMP-1 transfection. DNA damage was assessed by the Alkaline Comet Assay and cell survival was determined by a clonogenic assay. Caki-1 cell cycle alterations following TIMP-1 transfection were assessed by fluorescence activated cell sorting (FACS) analysis of propidium iodide (PI)-stained cells. The interactions between TIMP-1 and MMP-2 and MMP-9 were analysed 24 hours post-irradiation by means of gelatin zymography.

RESULTS

Three clones with varying degrees of TIMP-1 expression were selected and used for further analysis. TIMP-1 transfected Caki-1 cells displayed significantly higher mean tail moment values (p < 0.05) following irradiation at doses between 5 and 10 Gy relative to that seen with radiation alone. The TIMP-1 radiosensitizing effect was accompanied by large decreases in the survival fraction of the parental Caki-1 cell line and significant increases in the alpha-parameter of the linear-quadratic fit. These effects were directly correlated to the degree of TIMP-1 gene expression detected in the selected clones. Interestingly, elevated levels of TIMP-2 protein were detected in the three TIMP-1 clones compared to TIMP-2 levels present in Caki-l cells. The three clones also displayed marked phenotypic alterations relative to their parental cell line. Significant increases in the percentage of cells arrested in the G2/M phase of the cell cycle were detected in the three clones under normal growth conditions and reduced serum conditions (p < 0.05). When the TIMP-1 clones were assessed for their MMP-2 activity, a marked decrease in the MMP-2 mean protein levels was detected in clone T1-3 following irradiation at doses between 2 and 6 Grays (Gy) (p < 0.01) and clone T1-2 at 2- 5Gy (p < 0.05). MMP-9 activity was differentially affected by ionizing radiation in the three TIMP-1 clones. T1-3 and TI-2 displayed significantly reduced MMP-9 levels at various dose points whereas T1-1 exhibited elevated levels of MMP-9 activity at higher doses of treatment (p < 0.05).

CONCLUSION

These results demonstrate a dual role for the TIMP-1 overexpression in this renal carcinoma cell line, both as radiosensitizing agents and effectors of MMP-2 and MMP-9 activity.

Depsipeptide a histone deacetlyase inhibitor down regulates levels of matrix metalloproteinases 2 and 9 mRNA and protein expressions in lung cancer cells (A549)

BACKGROUND

A novel histone deacetylase inhibitor, depsipeptide FR901228 (FK228), is a promising anticancer and antiproliferative agent and has been proposed to regulate gene transcription and reported to lower the risk of several cancers in different cell lines. Depsipeptide showed therapeutic efficacy in Phase I trial of patients with malignant lymphoma. Based on the recognition that basement membrane disruption occurs in acute lung injury and that matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) can degrade type IV collagen, one of the major components of the basement membrane and known to involve in tumor invasion and metastases. We hypothesized that depsipeptide would modulate MMP-2 and MMP-9 production in lung adenocarcinoma cells line (A549).

METHODS

In this study, we observed the precise involvement of depsipeptide role on cancer metastasis. A549 cells were treated with depsipeptide at various concentrations (50 and 100nm), for 24h period and then subjected to mRNA levels with RT-PCR and protein levels with Western blot analysis to investigate the impact of depsipeptide on MMP-2 and MMP-9 expressions and further confirmed by using immunocytochemistry.

RESULTS

The results showed that depsipeptide treatment decreased the expressions of MMP-2 and MMP-9 in dose-dependent manner. The level of mRNA and proteins expressions were significantly decreased in depsipeptide treated A549 cells in a dose-dependent manner and the level of pro-MMP-9 was found to be high in the 100nm depsipeptide-treated cell lysate of A549 cells, suggesting inhibitory role of depsipeptide on pro-MMP-9 activation. Further immunocytochemistry studies showed the weak expression of MMP-2 and MMP-9 in depsipeptide treated cells.

CONCLUSION

We speculate that inhibition of metastasis-specific MMPs in cancer cells may be one of the targets for anticancer function of depsipeptide, and thus provides the molecular basis for the development of depsipeptide as a novel chemopreventive agent for metastatic lung cancer.

Radiation pneumonitis and fibrosis: Mechanisms underlying its pathogenesis and implications for future research

Radiation pneumonitis and subsequent radiation pulmonary fibrosis are the two main dose-limiting factors when irradiating the thorax that can have severe implications for patients' quality of life. In this article, the current concepts about the pathogenetic mechanisms underlying radiation pneumonitis and fibrosis are presented. The clinical course of fibrosis, a postulated acute inflammatory stage, and a late fibrotic and irreversible stage are discussed. The interplay of cells and the wide variety of molecules orchestrating the immunologic response to radiation, their interactions with specific receptors, and the cascade of events they trigger are elucidated. Finally, the implications of this knowledge with respect to the therapeutic interventions are critically presented.

Ionizing radiation suppresses FAP-1 mRNA level in A549 cells via p53 activation

Ionizing radiation (IR) is known to upregulate cell surface Fas through p53 activation in various cells. However, the signaling pathway intermediating between p53 activation and cell surface Fas upregulation remains to be elucidated. Recently, Fas-associated phosphatase-1 (FAP-1) has been reported to associate with Fas and inhibit cell surface Fas expression. We evaluated the expression of FAP-1 mRNA following IR in A549 cells. Ionizing radiation inhibited the expression of FAP-1 mRNA. Pretreatment with p53 inhibitor pifithrin alpha cancelled the IR-induced downregulation of FAP-1 mRNA. These results suggest that IR-induced p53 activation may upregulate cell surface Fas via the down-modulation of FAP-1.

Inhibition of matrix metalloproteinase-9 prevents neutrophilic inflammation in ventilator-induced lung injury

Neutrophils are considered to play a central role in ventilator-induced lung injury (VILI). However, the pulmonary consequences of neutrophil accumulation have not been fully elucidated. Matrix metalloproteinase-9 (MMP-9) had been postulated to participate in neutrophil transmigration. The purpose of this study was to investigate the role of MMP-9 in the neutrophilic inflammation of VILI. Male Sprague-Dawley rats were divided into three groups: 1) low tidal volume (LVT), 7 ml/kg of tidal volume (VT); 2) high tidal volume (HVT), 30 ml/kg of VT; and 3) HVT with MMP inhibitor (HVT+MMPI). As a MMPI, CMT-3 was administered daily from 3 days before mechanical ventilation. Degree of VILI was assessed by wet-to-dry weight ratio and acute lung injury (ALI) scores. Neutrophilic inflammation was determined from the neutrophil count in the lung tissue and myeloperoxidase (MPO) activity in the bronchoalveolar lavage fluid (BALF). MMP-9 expression and activity were examined by immunohistochemical staining and gelatinase zymography, respectively. The wet-to-dry weight ratio, ALI score, neutrophil infiltration, and MPO activity were increased significantly in the HVT group. However, in the HVT+MMPI group, pretreatment with MMPI decreased significantly the degree of VILI, as well as neutrophil infiltration and MPO activity. These changes correlated significantly with MMP-9 immunoreactivity and MMP-9 activity. Most outcomes were significantly worse in the HVT+MMPI group compared with the LVT group. In conclusion, VILI mediated by neutrophilic inflammation is closely related to MMP-9 expression and activity. The inhibition of MMP-9 protects against the development of VILI through the downregulation of neutrophil-mediated inflammation.

Matrix metalloproteinases in destructive pulmonary pathology

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that have a number of important physiological roles including remodelling of the extracellular matrix, facilitating cell migration, cleaving cytokines, and activating defensins. However, excess MMP activity may lead to tissue destruction. The biology of MMP and the role of these proteases in normal pulmonary immunity are reviewed, and evidence that implicates excess MMP activity in causing matrix breakdown in chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), sarcoidosis, and tuberculosis is discussed. Evidence from both clinical studies and animal models showing that stromal and inflammatory cell MMP expression leads to immunopathology is examined, and the mechanisms by which excess MMP activity may be targeted to improve clinical outcomes are discussed.

Radiation induced MMP expression from rectal cancer is short lived but contributes to in vitro invasion

AIMS

Matrix metalloproteinase (MMP) activity is increased after radiation. The aims of this study were to assess the time course of this increase and its effects on malignant cell invasion.

METHODS

Colorectal cancer (HCT 116, LoVo, C 170 HM 2, CaCO-2), fibroblast (46-BR.IGI, CCD-18 Co) and fibrosarcoma (HT1080) cell lines were irradiated at 4 gray (4 Gy) and matrix metalloproteinase gene and protein expression examined over a 96 h period by real time polymerase chain reaction and gelatin zymography. Invasion was assessed on Matrigel. Human rectal tumour MMP expression was compared before and after long course radiotherapy.

RESULTS

Radiation increased MMP gene expression of tumour cell lines, and resulted in increased MMP protein activity in the HT1080 line. HT1080 and HCT 116 in monoculture and LoVo in co-culture were more invasive after radiation at 48 h in vitro, but long course radiotherapy did not result in a consistent increase in MMP expression from human rectal tumour biopsies.

CONCLUSIONS

Radiation results in increased MMP expression for a limited time period. This results in an early increase in cell line invasion. Further clinical research is required to clarify if MMP inhibition given perioperatively following radiotherapy decreases local recurrence rates.

Radiation-induced gene expression profile of human cells deficient in 8-hydroxy-2′-deoxyguanine glycosylase

The human OGG1 gene encodes a DNA glycosylase that is involved in the base excision repair of 8-hydroxy-2'-deoxyguanine (8-OH-dG) from oxidatively damaged DNA. Cellular 8-OH-dG levels accumulate in the absence of this activity and could be deleterious for the cell. To assess the role of 8-oxoguanine glycosylase (OGG1) in the cellular defense mechanism in a specific DNA repair defect background, we set out to determine the expression pattern of base excision repair genes and other cellular genes not involved in the base excision pathway in OGG1-deficient human KG-1 cells after ionizing radiation exposure. KG-1 cells have lost OGG1 activity due to a homozygous mutation of Arg229Gln. Gene expression alterations were monitored at 4, 8, 12 and 24 hr in 2 Gy irradiated cells. Large-scale gene expression profiling was assessed with DNA microarray technology. Gene expression analysis identified a number of ionizing radiation-responsive genes, including several novel genes. There were 2 peaks of radiation-induced gene induction or repression: one at 8 hr and the other at 24 hr. Overall the number of downregulated genes was higher than the number of upregulated genes. The highest number of downregulated genes was at 8 hr postirradiation. Genes corresponding to cellular, physiologic, developmental and extracellular processes were identified. The highest number of radiation-induced genes belonged to the signal transduction category, followed by genes involved in transcription and response to stress. Microarray gene expression data were independently validated by relative quantitative RT-PCR. Surprisingly, none of the genes involved in the base excision repair of radiation-induced DNA damage showed altered expression.

Prognostic Significance of Stromelysin-3 and Tissue Inhibitor of Matrix Metalloproteinase-2 in Esophageal Cancer

OBJECTIVE

Stromelysins (matrix metalloproteinases: MMP-10 or ST-2 and MMP-11 or ST-3) and tissue inhibitors of matrix metalloproteinases (TIMP-1 and 2) have been shown to be associated with human tumor progression, invasion and metastasis. The aim of the present study was to determine the prognostic significance of these proteins in esophageal squamous cell carcinoma (ESCC).

METHODS

Immunohistochemical analysis was carried out in 65 surgically resected ESCCs and 49 distant histologically normal esophageal tissues and 16 cases of dysplasias. Statistical analyses were performed to determine the associations between the protein expression and clinicopathological parameters and survival of esophageal cancer patients.

RESULTS

Expression of ST-2, ST-3, TIMP-1 and TIMP-2 was observed in 43/65 (66%), 51/65 (78%), 43/65 (66%) and 47/65 (72%) ESCC cases, respectively. Univariate analysis showed that TIMP-2 expression was associated with tumor site (OR = 2.63, p = 0.017). TIMP-1+/TIMP-2+ phenotype was inversely correlated with nodal invasiveness of the tumor (OR = 0.4, p = 0.04). Interestingly, p53 expression was associated with increased levels of ST-3 (OR = 0.11, p = 0.02) and TIMP-1 (OR = 3.2, p = 0.007) suggesting possible involvement of p53 in the regulation of these proteins. An increased expression of ST-2, ST-3, TIMP-1 and TIMP-2 was observed in 11/16 (69%), 7/17 (44%), 11/16 (69%) and 8/16 (50%) dysplasias also suggesting that these alterations are early events in esophageal tumorigenesis. All the ESCC patients were followed up postesophagectomy for a maximum period of 59 months (mean disease-free survival = 12 months). Kaplan-Meier survival analysis showed that patients with ST-3-positive and TIMP-2-negative carcinoma had a significantly shorter disease-free survival (median disease-free survival time of 4 months) as compared to patients in the other groups (median disease-free survival time of 20 months; p = 0.0016). To our knowledge this is the first report showing that ST-3+/TIMP-2- phenotype remained of significant predictive value for disease-free survival (p = 0.0007) in multivariate analysis including a conventional clinicopathological factor, tumor stage (p = 0.051).

CONCLUSION

Our results suggest that ST-3+/TIMP-2- phenotype is an adverse prognosticator in esophageal cancer patients.

Activity of lung neutrophils and matrix metalloproteinases in cyclophosphamide-treated mice with experimental sepsis

Sepsis in patients receiving chemotherapy may result in acute respiratory distress syndrome, despite decreased number of blood neutrophils [polymorphonuclear neutrophils (PMNs)]. In the present study, we investigated the correlation of cyclophosphamide (CY)-induced neutropenia with the destructive potential of lung PMN in respect to formation of septic acute lung injury (ALI). Mice were treated with 250 mg/kg of CY or saline (control) and subjected to cecal ligation and puncture (CLP) or sham operation. ALI was verified by histological examination. Lung PMNs and matrix metalloproteinases (MMPs) were assessed by flow cytometry and gelatin zymography. CLP in CY-treated mice induced a typical lung injury. Despite profound neutropenia, CY treatment did not attenuate CLP-induced ALI. This might relate to only a partial suppression of PMN: CY has significantly reduced PMN influx into the lungs (P = 0.008) and suppressed their oxidative metabolism, but had no suppressive effect on degranulation (P = 0.227) and even induced MMP-9 activity (P = 0.0003). In CY-untreated animals, peak of CLP-induced ALI coincided with massive PMN influx (P = 0.013), their maximal degranulation (P = 0.014) and activation of lung MMP-9 (P = 0.002). These findings may indicate an important role of the residual lung PMN and activation of MMP-9 in septic lung injury during CY chemotherapy.

Radiation-Induced Up-regulation of Mmp2 Involves Increased mRNA Stability, Redox Modulation, and MAPK Activation

We have previously observed time- and dose-dependent increases in matrix metalloproteinase 2 (Mmp2) protein levels in rat tubule epithelial cells (NRK52E) after irradiation. However, the mechanism(s) involved remains unclear. In the present study, irradiating NRK52E cells with 0-20 Gy gamma rays was associated with time- and dose-dependent increases in Mmp2 mRNA. Studies using the transcription inhibitor actinomycin D (ActD) added 24 h after irradiation revealed the t(1/2) of Mmp2 mRNA to be approximately 8 h in control cells. In contrast, the increase in Mmp2 mRNA levels in irradiated cells was essentially unchanged after incubation with ActD for up to 12 h. Incubating cells with the antioxidants N-acetylcysteine or ebselen or the MEK pathway inhibitors PD98059 and U0126 prior to irradiation abolished the radiation-induced up-regulation of Mmp2. Irradiating NRK52E cells led to reactive oxygen species-mediated Erk1/2 activation; preincubation with NAC prevented the radiation-induced increase in phosphorylated Erk1/2. Transfecting cells with a dominant-negative ERK mutant completely inhibited radiation-induced Erk phosphorylation and abolished the radiation-induced up-regulation of Mmp2 protein. Thus the radiation-induced up-regulation of Mmp2 mRNA is due in part to increased mRNA stability and is mediated by redox; the ERK MAPK signaling pathway may be involved.

Combinatorial interactions of p53, activating protein-2, and YB-1 with a single enhancer element regulate gelatinase A expression in neoplastic cells

Gelatinase A, also denoted matrix metalloproteinase 2, plays multiple critical roles in the neoplastic process, including facilitation of neoangiogenesis and formation of distal metastases. The transcriptional regulation of the gelatinase A gene is under the control of strong, evolutionarily conserved cis-acting enhancer elements, designated the r2 (human) or RE-1 (rat), that harbor contiguous binding motifs for the transcription factors activating protein-2 (AP2), p53, and YB-1. Using recombinant transcription factors, complex patterns of RE-1 binding were observed by electrophoretic mobility shift assay. Increased complex formation was detected with the AP2/YB-1 and AP2/p53 combinations, while YB-1 competed with p53 for binding. The combination of AP2, p53, and YB-1 yielded novel ternary complexes, particularly when binding to single-stranded RE-1 probes. Transient transfection of hepatocellular carcinoma cell lines with a series of gelatinase A luciferase reporter constructs were in accordance with the binding patterns determined by electrophoretic mobility shift assay. Combined AP2 and p53 increased gelatinase A luciferase reporter activity significantly, and the inclusion of YB-1 yielded further increase in both reporter activity and secreted levels of gelatinase A protein. YB-1 and p53 expression are increased following multiple genotoxic stresses, including irradiation, and the synergistic interactions of these induced transcription factors with the widely expressed AP2 protein provide a probable pathophysiologic mechanism for the enhanced tumor cell synthesis of gelatinase A induced by radiation.