共查询到20条相似文献,搜索用时 31 毫秒
1.
Kunal N. More Jun Young Lee Dong-Yeon Kim Nam-Chul Cho Ayoung Pyo Misun Yun Hyeon Sik Kim Hangun Kim Kwangseok Ko Jeong-Hoon Park Dong-Jo Chang 《Bioorganic & medicinal chemistry letters》2018,28(5):915-921
Carbonic anhydrase IX is overexpressed in many solid tumors including hypoxic tumors and is a potential target for cancer therapy and diagnosis. Reported imaging agents targeting CA-IX are successful mostly in clear cell renal carcinoma as SKRC-52 and no candidate was approved yet in clinical trials for imaging of CA-IX. To validate CA-IX as a valid target for imaging of hypoxic tumor, we designed and synthesized novel [18F]-PET tracer (1) based on acetazolamide which is one of the well-known CA-IX inhibitors and performed imaging study in CA-IX expressing hypoxic tumor model as 4T1 and HT-29 in vivo models other than SKRC-52. [18F]-acetazolamide (1) was found to be insufficient for the specific accumulation in CA-IX expressing tumor. This study might be useful to understand in vivo behavior of acetazolamide PET tracer and can contribute to the development of successful PET imaging agents targeting CA-IX in future. Additional study is needed to understand the mechanism of poor targeting of CA-IX, as if CA-IX is not reliable as a sole target for imaging of CA-IX expressing hypoxic solid tumors. 相似文献
2.
Jae-Keun Cho Seung Hyup Hyun Nayeon Choi Min-Ji Kim Timothy P. Padera Joon Young Choi Han-Sin Jeong 《Translational oncology》2015,8(2):119-125
Lymph node metastasis (LNM) in many solid cancers is a well-known prognostic factor; however, it has been debated whether regional LNM simply reflects tumor aggressiveness or is a source for further tumor dissemination. Similarly, the metastatic process in head and neck cancer (HNC) has not been fully evaluated. Thus, we aimed to investigate the relative significance of LNM in metastatic cascade of HNC using functional imaging of HNC patients and molecular imaging in in vivo models. First, we analyzed 18Fluorodeoxyglucose positron emission tomography (PET) parameters of 117 patients with oral cancer. The primary tumor and nodal PET parameters were measured separately, and survival analyses were conducted on the basis of clinical and PET variables to identify significant prognostic factors. In multivariate analyses, we found that only the metastatic node PET values were significant. Next, we compared the relative frequency of lung metastasis in primary ear tumors versus lymph node (LN) tumors, and we tested the rate of lung metastasis in another animal model, in which each animal had both primary and LN tumors that were expressing different colors. As a result, LN tumors showed higher frequencies of lung metastasis compared to orthotopic primary tumors. In color-matched comparisons, the relative contribution to lung metastasis was higher in LN tumors than in primary tumors, although both primary and LN tumors caused lung metastases. In summary, tumors growing in the LN microenvironment spread to systemic sites more commonly than primary tumors in HNC, suggesting that the adequate management of LNM can reduce further systemic metastasis. 相似文献
3.
Erica C. Nakajima Charles Laymon Matthew Oborski Weizhou Hou Lin Wang Jennifer R. Grandis Robert L. Ferris James M. Mountz Bennett Van Houten 《PloS one》2014,9(8)
Purpose
Intratumoral metabolic heterogeneity may increase the likelihood of treatment failure due to the presence of a subset of resistant tumor cells. Using a head and neck squamous cell carcinoma (HNSCC) xenograft model and a real-time fluorescence imaging approach, we tested the hypothesis that tumors are metabolically heterogeneous, and that tumor hypoxia alters patterns of glucose uptake within the tumor.Experimental Design
Cal33 cells were grown as xenograft tumors (n = 16) in nude mice after identification of this cell line''s metabolic response to hypoxia. Tumor uptake of fluorescent markers identifying hypoxia, glucose import, or vascularity was imaged simultaneously using fluorescent molecular tomography. The variability of intratumoral 2-deoxyglucose (IR800-2-DG) concentration was used to assess tumor metabolic heterogeneity, which was further investigated using immunohistochemistry for expression of key metabolic enzymes. HNSCC tumors in patients were assessed for intratumoral variability of 18F-fluorodeoxyglucose (18F-FDG) uptake in clinical PET scans.Results
IR800-2-DG uptake in hypoxic regions of Cal33 tumors was 2.04 times higher compared to the whole tumor (p = 0.0001). IR800-2-DG uptake in tumors containing hypoxic regions was more heterogeneous as compared to tumors lacking a hypoxic signal. Immunohistochemistry staining for HIF-1α, carbonic anhydrase 9, and ATP synthase subunit 5β confirmed xenograft metabolic heterogeneity. We detected heterogeneous 18F-FDG uptake within patient HNSCC tumors, and the degree of heterogeneity varied amongst tumors.Conclusion
Hypoxia is associated with increased intratumoral metabolic heterogeneity. 18F-FDG PET scans may be used to stratify patients according to the metabolic heterogeneity within their tumors, which could be an indicator of prognosis. 相似文献4.
Assessment of fraction of hypoxic cells in human tumor xenografts with necrotic regions by dynamic contrast-enhanced MRI 总被引:1,自引:0,他引:1
Egeland TA Gaustad JV Benjaminsen IC Hedalen K Mathiesen B Rofstad EK 《Radiation research》2008,169(6):689-699
The potential usefulness of gadopentetate dimeglumine (Gd-DTPA)-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for assessing hypoxia in tumors with significant necrosis was investigated. Small (100-350 mm(3)) and large (500-1000 mm(3)) D-12 and U-25 tumors were subjected to DCE-MRI, measurement of the fraction of necrotic tissue, and measurement of the fraction of radiobiologically hypoxic cells. Images of E.F (E is the initial extraction fraction of Gd-DTPA and F is perfusion) and lambda (lambda is proportional to extracellular volume fraction) were produced by subjecting the DCE-MRI data to Kety analysis. Necrotic tissue could be identified in lambda images but not in E.F images of the tumors. Most voxels in viable tissue showed lambda values of 0.15-0.70, whereas the lambda values of most voxels in necrotic tissue were either <0.15 or >0.70. The E.F and lambda frequency distributions of the viable tissue, but not the E.F and lambda frequency distributions of the whole tissue, were consistent with the observation that the four groups of tumors showed similar fractions of radiobiologically hypoxic cells. E.F and lambda images may thus provide useful information on the extent of hypoxia in tumors provided that voxels in necrotic tumor regions are identified and excluded from the images. 相似文献
5.
Rehan Ali Sandeep Apte Marta Vilalta Murugesan Subbarayan Zheng Miao Frederick T. Chin Edward E. Graves 《PloS one》2015,10(10)
We evaluated the relationship between pre-treatment positron emission tomography (PET) using the hypoxic tracer 18F-[2-(2-nitro-1-H-imidazol-1-yl)-N-(2,2,3,3,3- pentafluoropropyl) acetamide] (18F-EF5) and the response of preclinical tumor models to a range of fractionated radiotherapies. Subcutaneous HT29, A549 and RKO tumors grown in nude mice were imaged using 18F-EF5 positron emission tomography (PET) in order to characterize the extent and heterogeneity of hypoxia in these systems. Based on these results, 80 A549 tumors were subsequently grown and imaged using 18F-EF5 PET, and then treated with one, two, or four fraction radiation treatments to a total dose of 10–40 Gy. Response was monitored by serial caliper measurements of tumor volume. Longitudinal post-treatment 18F-EF5 PET imaging was performed on a subset of tumors. Terminal histologic analysis was performed to validate 18F-EF5 PET measures of hypoxia. EF5-positive tumors responded more poorly to low dose single fraction irradiation relative to EF5-negative tumors, however both groups responded similarly to larger single fraction doses. Irradiated tumors exhibited reduced 18F-EF5 uptake one month after treatment compared to control tumors. These findings indicate that pre- treatment 18F-EF5 PET can predict the response of tumors to single fraction radiation treatment. However, increasing the number of fractions delivered abrogates the difference in response between tumors with high and low EF5 uptake pre-treatment, in agreement with traditional radiobiology. 相似文献
6.
~(18)F-FDG PET/CT常规代谢成像反应肿瘤的葡萄糖代谢及乏氧情况,而~(18)F-FDG PET/CT早期动态成像能反映PET/CT成像早期肿瘤的灌注情况。由于肿瘤的异质性,在早期动态~(18)F-FDG PET/CT成像,即~(18)F-FDG PET/CT灌注成像中,存在独立于常规60 min~(18)F-FDG PET/CT代谢成像的SUVmax(最大标准摄取值)高摄取区。因此,在临床工作中应用~(18)F-FDG PET/CT早期动态成像,能够进一步对实体肿瘤的活性区域进行评估,能够更好评价患者预后、完善治疗方案。当前~(18)F-FDG早期动态成像已经应用在肝癌、肾癌以及膀胱癌等实体肿瘤诊断中。早期动态~(18)F-FDG PET/CT成像结合常规标准~(18)F-FDG PET/CT代谢成像,对实体肿块进行一站式成像方法,能够更好的对肿瘤进行评估。 相似文献
7.
Yoann Joyard Vadim Le Joncour Hélène Castel Chérif Bounana Diouf Laurent Bischoff Cyril Papamicaël Vincent Levacher Pierre Vera Pierre Bohn 《Bioorganic & medicinal chemistry letters》2013,23(13):3704-3708
Tumor hypoxia plays a major role in reducing the efficacy of therapeutic modalities like chemotherapy and radiation therapy in combating cancer. In order to target hypoxic tissues, a tripeptide ligand having a 2-nitroimidazole moiety, as a bioreductive species, was synthesized. The latter was radiolabeled with 99mTc for imaging hypoxic regions of tumors and was characterized by means of its rhenium analogue. The biodistribution and scintigraphic image of the corresponding 99mTc-complex showed accumulation in tumor and these results suggest that it could be a marker for imaging tumor hypoxia. 相似文献
8.
Bing Yu Amy Shah Bingqing Wang Narasimhan Rajaram Quanli Wang Nirmala Ramanujam Gregory M. Palmer Mark W. Dewhirst 《Journal of biophotonics》2014,7(7):552-564
Hypoxia and angiogenesis can significantly influence the efficacy of cancer therapy and the behavior of surviving tumor cells. There is a growing demand for technologies to measure tumor hypoxia and angiogenesis temporally in vivo to enable advances in drug development and optimization. This paper reports the use of frequency‐domain photon migration with a side‐firing probe to quantify tumor oxygenation and hemoglobin concentrations in nude rats bearing human head/neck tumors administered with carbogen gas, cycling hypoxic gas or just room air. Significant increase (with carbogen gas breathing) or decrease (with hypoxic gas breathing) in tumor oxygenation was observed. The trend in tumor oxygenation during forced cycling hypoxia (CH) followed that of the blood oxygenation measured with a pulse oximeter. Natural CH was also observed in rats under room air. The studies demonstrated the potential of the technology for longitudinal monitoring of tumor CH during tumor growth or in response to therapy. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
IntroductionThe increased radioresistance of hypoxic cells compared to well-oxygenated cells is quantified by the oxygen enhancement ratio (OER). In this study we created a FLUKA Monte Carlo based tool for inclusion of both OER and relative biological effectiveness (RBE) in biologically weighted dose (ROWD) calculations in proton therapy and applied this to explore the impact of hypoxia.MethodsThe RBE-weighted dose was adapted for hypoxia by making RBE model parameters dependent on the OER, in addition to the linear energy transfer (LET). The OER depends on the partial oxygen pressure (pO2) and LET. To demonstrate model performance, calculations were done with spread-out Bragg peaks (SOBP) in water phantoms with pO2 ranging from strongly hypoxic to normoxic (0.01–30 mmHg) and with a head and neck cancer proton plan optimized with an RBE of 1.1 and pO2 estimated voxel-by-voxel using [18F]-EF5 PET. An RBE of 1.1 and the Rørvik RBE model were used for the ROWD calculations.ResultsThe SOBP in water had decreasing ROWD with decreasing pO2. In the plans accounting for oxygenation, the median target doses were approximately a factor 1.1 lower than the corresponding plans which did not consider the OER. Hypoxia adapted target ROWDs were considerably more heterogeneous than the RBE1.1-weighted doses.ConclusionWe realized a Monte Carlo based tool for calculating the ROWD. Read-in of patient pO2 and estimation of ROWD with flexibility in choice of RBE model was achieved, giving a tool that may be useful in future clinical applications of hypoxia-guided particle therapy. 相似文献
10.
P. Brandmaier S. Purz K. Bremicker M. H?ckel H. Barthel R. Kluge T. Kahn O. Sabri P. Stumpp 《PloS one》2015,10(11)
Objectives
Previous non–simultaneous PET/MR studies have shown heterogeneous results about the correlation between standardized uptake values (SUVs) and apparent diffusion coefficients (ADCs). The aim of this study was to investigate correlations in patients with primary and recurrent tumors using a simultaneous PET/MRI system which could lead to a better understanding of tumor biology and might play a role in early response assessment.Methods
We included 31 patients with histologically confirmed primary (n = 14) or recurrent cervical cancer (n = 17) who underwent simultaneous whole-body 18F-FDG-PET/MRI comprising DWI. Image analysis was performed by a radiologist and a nuclear physician who identified tumor margins and quantified ADC and SUV. Pearson correlations were calculated to investigate the association between ADC and SUV.Results
92 lesions were detected. We found a significant inverse correlation between SUVmax and ADCmin (r = -0.532, p = 0.05) in primary tumors as well as in primary metastases (r = -0.362, p = 0.05) and between SUVmean and ADCmin (r = -0.403, p = 0.03). In recurrent local tumors we found correlations for SUVmax and ADCmin (r = -0.747, p = 0.002) and SUVmean and ADCmin (r = -0.773, p = 0.001). Associations for recurrent metastases were not significant (p>0.05).Conclusions
Our study demonstrates the feasibility of fast and reliable measurement of SUV and ADC with simultaneous PET/MRI. In patients with cervical cancer we found significant inverse correlations for SUV and ADC which could play a major role for further tumor characterization and therapy decisions.Key Point 1
This study investigates the correlation of functional parameters in a simultaneous PET/MRI.Key Point 2
We found significant inverse correlations between ADC and SUV in cervical carcinoma which could increase knowledge about tumor biology. 相似文献11.
Kardosh A Soriano N Pyrko P Liu YT Jabbour M Hofman FM Schönthal AH 《Journal of biomedical science》2007,14(5):647-662
Hypoxia is a characteristic feature of advanced solid tumors and may worsen prognosis. The development of tumor-targeted and
hypoxia-inducible gene therapy vectors holds promise to selectively deliver and express suicidal or cytotoxic genes in hypoxic
regions of tumors. In this regard, the promoter of the survivin gene, which encodes an anti-apoptotic protein that is strongly
expressed in tumor tissue, has received attention because of its supposed inducibility by hypoxia. However, in our present
study we demonstrate that treatment of various tumor cell lines with chronic hypoxia or with the hypoxia-mimetic CoCl2 does not result in increased expression of survivin, but rather strongly suppresses this gene’s activity. In contrast, expression
of glucose-regulated protein 78 (GRP78/Bip) is substantially elevated under chronic hypoxia in vitro and in hypoxic areas of tumor tissue in vivo. Although tumor cells in general exhibit increased chemoresistance under hypoxic conditions, we found that hypoxic glioblastoma
cells are more sensitive to killing by the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib, and this effect is reflected
by further decreased expression of survivin. Intriguingly, 2,5-dimethyl-celecoxib (DMC), a close structural analog of celecoxib
that lacks the ability to inhibit COX-2, is able to potently mimic the anti-tumor effects of its parent compound, indicating
that inhibition of COX-2 is not involved in these processes. Taken together, our results caution against the use of survivin-based
promoters to target hypoxic areas of tumors, but favor constructs that include the strongly hypoxia-inducible GRP78 promoter.
In addition, our data introduce celecoxib as a drug with increased cytotoxicity against hypoxic tumor cells. 相似文献
12.
Sadaaki Kimura Izumi O. Umeda Noriyuki Moriyama Hirofumi Fujii 《Bioorganic & medicinal chemistry letters》2011,21(24):7359
Tumor hypoxia is closely associated with the malignant progression and/or the high metastatic ability of tumors and often induces resistance to chemo- and/or radiotherapy. Thus, the detection and evaluation of hypoxia is important for the optimization of cancer therapy. We designed a novel 99mTc-labeled probe for tumor hypoxia imaging that utilizes bioreductive reactions in hypoxic cells. This probe, which contains a 4-nitrobenzyl ester group, is reduced in hypoxic cells to produce a corresponding carboxylate anion that cannot penetrate cell membranes because of its hydrophilicity and negative charge; therefore, it is expected to be trapped inside hypoxic cells. Based on this unique strategy, we synthesized the Technetium-99m (99mTc)-labeled probe 99mTc-SD32. The uptake of 99mTc-SD32 in tumor cells was investigated under normoxic and hypoxic conditions. 99mTc-SD32 showed sufficient accumulation and good retention in hypoxic cells. In addition, we demonstrated that 99mTc-SD32 was subjected to bioreduction in hypoxic cells and was trapped as the corresponding carboxylate anion. These results indicated that 99mTc-SD32 would be a promising agent for in vivo hypoxia imaging. 相似文献
13.
Correlation of tumor oxygen dynamics with radiation response of the dunning prostate R3327-HI tumor 总被引:2,自引:0,他引:2
Our previous studies have shown that oxygen inhalation significantly reduces tumor hypoxia in the moderately well-differentiated HI subline of the Dunning prostate R3327 rat carcinoma. To test our hypothesis that modifying hypoxia could improve the radiosensitivity of these tumors, we performed experimental radiotherapy to compare the tumor response to ionizing radiation alone or in combination with oxygen inhalation. Tumor pO(2) measurements were performed on size-selected tumors several hours before radiotherapy using (19)F nuclear magnetic resonance echo planar imaging relaxometry (FREDOM) of the reporter molecule hexafluorobenzene. In common with our previous findings, the larger tumors (>3.5 cm(3)) exhibited greater hypoxia than the smaller tumors (<2 cm(3); P < 0.001), and oxygen inhalation reduced the hypoxic fraction (<10 Torr): In the larger tumors, hypoxic fraction dropped significantly from a mean baseline value of 80% to 17% (P < 0.001). The effect of oxygen administered 30 min before and during irradiation on tumor response to a single 30-Gy dose of photons was evaluated by growth delay. For the smaller tumors, no difference in growth delay was found when treatment was given with or without oxygen breathing. By contrast, breathing oxygen before and during irradiation significantly enhanced the growth delay in the larger tumors (additional 51 days). The differential behavior may be attributed to the low baseline hypoxic fraction (<10 Torr) in small tumors (20%) as a target for oxygen inhalation. There was a strong correlation between the estimated initial pO(2) value and the radiation-induced tumor growth delay (R > 0.8). Our histological studies showed a good match between the perfused vessels marked by Hoechst 33342 dye and the total vessels immunostained by anti-CD31 and indicated extensive perfusion in this tumor line. In summary, the present results suggest that the ability to detect modulation of tumor pO(2), in particular, the residual hypoxic fraction, with respect to an intervention, could have prognostic value for predicting the efficacy of radiotherapy. 相似文献
14.
PurposeDiagnostic positron emission tomography and computed tomography (PET/CT) images can be fused to the planning CT images by a deformable image registration (DIR). The aim of this study was to evaluate the standardized uptake value (SUV) and target delineation on deformed PET images.MethodsWe used a cylindrical phantom and removable inserts of four spheres (16–38 mm in diameter) and three ellipsoids with a volume equal to the 38-mm-diameter sphere (S38) in each. S38 was filled with 18F-fluorodeoxyglucose activity, and then PET/CT images were acquired. The contours of S38 were generated using original PET images by PET auto-segmentation (PET-AS) methods of (1) SUV2.5, (2) 40% of maximum SUV (SUV40%max), and (3) gradient-based (GB), and were deformed to the other inserts by DIR. We compared the volumes and the SUVmax with the generated contours using the deformed PET images.ResultsThe SUVmax was slightly decreased by DIR; the mean absolute difference was −0.10 ± 0.04. For SUV2.5 and SUV40%max, the differences in S38 volumes between the original and deformed PET images were less than 5%, regardless of deformation type. For the GB, the contoured volumes obtained from deformed PET images were larger than those of the original PET images for the deformation type of ellipsoids. When the S38 was deformed to the 16-mm-diameter sphere, the maximum volume difference was −22.8%.ConclusionsAlthough SUV fluctuations by DIR were negligible, the target delineation on deformed PET images by the GB should be carefully considered owing to the distortion of intensity profiles. 相似文献
15.
PurposeTo investigate the robustness of PET radiomic features (RF) against tumour delineation uncertainty in two clinically relevant situations.MethodsTwenty-five head-and-neck (HN) and 25 pancreatic cancer patients previously treated with 18F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT)-based planning optimization were considered. Seven FDG-based contours were delineated for tumour (T) and positive lymph nodes (N, for HN patients only) following manual (2 observers), semi-automatic (based on SUV maximum gradient: PET_Edge) and automatic (40%, 50%, 60%, 70% SUV_max thresholds) methods. Seventy-three RF (14 of first order and 59 of higher order) were extracted using the CGITA software (v.1.4). The impact of delineation on volume agreement and RF was assessed by DICE and Intra-class Correlation Coefficients (ICC).ResultsA large disagreement between manual and SUV_max method was found for thresholds ≥50%. Inter-observer variability showed median DICE values between 0.81 (HN-T) and 0.73 (pancreas). Volumes defined by PET_Edge were better consistent with the manual ones compared to SUV40%. Regarding RF, 19%/19%/47% of the features showed ICC < 0.80 between observers for HN-N/HN-T/pancreas, mostly in the Voxel-alignment matrix and in the intensity-size zone matrix families. RFs with ICC < 0.80 against manual delineation (taking the worst value) increased to 44%/36%/61% for PET_Edge and to 69%/53%/75% for SUV40%.ConclusionsAbout 80%/50% of 72 RF were consistent between observers for HN/pancreas patients. PET_edge was sufficiently robust against manual delineation while SUV40% showed a worse performance. This result suggests the possibility to replace manual with semi-automatic delineation of HN and pancreas tumours in studies including PET radiomic analyses. 相似文献
16.
PurposeThe present study aimed to define the errors in SUV and demonstrate the feasibility of SUV harmonization among contemporary PET/CT scanners using a novel National Institute of Standards and Technology (NIST)-traceable 68Ge/68Ga source as the reference standard.MethodsWe used 68Ge/68Ga dose calibrator and PET sources made with same batch of 68Ge/68Ga embedded in epoxy that is traceable to the NIST standard. Bias in the amount of radioactivity and the radioactive concentrations measured by the dose calibrators and PET/CT scanners, respectively, was determined at five Japanese sites. We adjusted optimal dial setting of the dose calibrators and PET reconstruction parameters to close the actual amount of radioactivity and the radioactive concentration, respectively, of the NIST-traceable 68Ge/68Ga sources to harmonize SUV. Errors in SUV before and after harmonization were then calculated at each site.ResultsThe average bias in the amount of radioactivity and the radioactive concentrations measured by dose calibrator and PET scanner was −4.94% and −12.22%, respectively, before, and −0.14% and −4.81%, respectively, after harmonization. Corresponding averaged errors in SUV measured under clinical conditions were underestimated by 7.66%, but improved by −4.70% under optimal conditions.ConclusionOur proposed method using an NIST-traceable 68Ge/68Ga source identified bias in values obtained using dose calibrators and PET scanners, and reduced SUV variability to within 5% across different models of PET scanners at five sites. Our protocol using a standard source has considerable potential for harmonizing the SUV when contemporary PET scanners are involved in multicenter studies. 相似文献
17.
Barry Jutten Tom G. Keulers Hanneke J. M. Peeters Marco B. E. Schaaf Kim G. M. Savelkouls Inge Compter 《Autophagy》2018,14(2):283-295
Expression of EGFRvIII is frequently observed in glioblastoma and is associated with increased cellular proliferation, enhanced tolerance to metabolic stresses, accelerated tumor growth, therapy resistance and poor prognosis. We observed that expression of EGFRvIII elevates the activation of macroautophagy/autophagy during starvation and hypoxia and explored the underlying mechanism and consequence. Autophagy was inhibited (genetically or pharmacologically) and its consequence for tolerance to metabolic stress and its therapeutic potential in (EGFRvIII+) glioblastoma was assessed in cellular systems, (patient derived) tumor xenopgrafts and glioblastoma patients. Autophagy inhibition abrogated the enhanced proliferation and survival advantage of EGFRvIII+ cells during stress conditions, decreased tumor hypoxia and delayed tumor growth in EGFRvIII+ tumors. These effects can be attributed to the supporting role of autophagy in meeting the high metabolic demand of EGFRvIII+ cells. As hypoxic tumor cells greatly contribute to therapy resistance, autophagy inhibition revokes the radioresistant phenotype of EGFRvIII+ tumors in (patient derived) xenograft tumors. In line with these findings, retrospective analysis of glioblastoma patients indicated that chloroquine treatment improves survival of all glioblastoma patients, but patients with EGFRvIII+ glioblastoma benefited most. Our findings disclose the unique autophagy dependency of EGFRvIII+ glioblastoma as a therapeutic opportunity. Chloroquine treatment may therefore be considered as an additional treatment strategy for glioblastoma patients and can reverse the worse prognosis of patients with EGFRvIII+ glioblastoma. 相似文献
18.
Gianluca Mirizzi Alberto Giannoni Andrea Ripoli Giovanni Iudice Francesca Bramanti Michele Emdin Claudio Passino 《PloS one》2016,11(4)
BackgroundPeripheral and central chemoreflex sensitivity, assessed by the hypoxic or hypercapnic ventilatory response (HVR and HCVR, respectively), is enhanced in heart failure (HF) patients, is involved in the pathophysiology of the disease, and is under investigation as a potential therapeutic target. Chemoreflex sensitivity assessment is however demanding and, therefore, not easily applicable in the clinical setting. We aimed at evaluating whether common clinical variables, broadly obtained by routine clinical and instrumental evaluation, could predict increased HVR and HCVR.ConclusionsIn HF patients, the simple assessment of breathing pattern, alongside with ventilatory efficiency during exercise and natriuretic peptides levels identifies a subset of patients presenting with increased chemoreflex sensitivity to either hypoxia or hypercapnia. 相似文献
19.
Cornelius Schmaltz Patricia Harrigan Hardenbergh Audrey Wells David E. Fisher 《Molecular and cellular biology》1998,18(5):2845-2854
Hypoxia may influence tumor biology in paradoxically opposing ways: it is lethal as a direct stress trigger, yet hypoxic zones in solid tumors harbor viable cells which are particularly resistant to treatment and contribute importantly to disease relapse. To examine mechanisms underlying growth-survival decisions during hypoxia, we have compared genetically related transformed and untransformed fibroblast cells in vitro for proliferation, survival, clonogenicity, cell cycle, and p53 expression. Hypoxia induces G0/G1 arrest in primary fibroblasts but triggers apoptosis in oncogene-transformed derivatives. Unexpectedly, the mechanism of apoptosis is seen to require accumulated acidosis and is rescued by enhanced buffering. The direct effect of hypoxia under nonacidotic conditions is unique to transformed cells in that they override the hypoxic G0/G1 arrest of primary cells. Moreover, when uncoupled from acidosis, hypoxia enhances tumor cell viability and clonogenicity relative to normoxia. p53 is correspondingly upregulated in response to hypoxia-induced acidosis but downregulated during hypoxia without acidosis. Hypoxia may thus produce both treatment resistance and a growth advantage. Given strong evidence that hypoxic regions in solid tumors are often nonacidotic (G. Helmlinger, F. Yuan, M. Dellian, and R. K. Jain, Nat. Med. 3:177–182, 1997), this behavior may influence relapse and implicates such cells as potentially important therapeutic targets. 相似文献
20.
The sustenance of most solid tumors including head and neck cancers (HNCs) is strongly dependent on the presence of a functioning vascular network. In this study, we examined the acute effects of a tumor vascular disrupting agent (VDA), 5,6-dimethylxanthenone-4-acetic acid (DMXAA; ASA404), in an orthotopic model of human HNC. Noninvasive magnetic resonance imaging (MRI) was used to monitor the vascular response of orthotopic FaDu xenografts to VDA therapy. Untreated tumors showed a marked but heterogeneous pattern of enhancement after contrast agent injection on serial T1-weighted (T1W) MR images. After VDA treatment, T2W and T1W MRI revealed evidence of hemorrhaging and lack of functioning vessels (enhancement) within the tumor. Quantitative estimates of relative vascular volume also showed a significant (P < .01) reduction in DMXAA-treated tumors 24 hours after therapy compared with untreated controls. Histology and immunostaining of untreated orthotopic FaDu tumors revealed poorly differentiated squamous cell carcinoma histology with distinctly visible CD31+ endothelial cells. In sharp contrast, minimal CD31 staining with irregular endothelial fragments and faint outlines of blood vessels were seen in DMXAA-treated tumor sections. CD31 immunostaining and histology also highlighted the selectivity of vascular damage and tissue necrosis after VDA therapy with no evidence of toxicity observed in normal salivary gland, heart, liver, and skeletal muscle tissues. Together, our results demonstrate a potent and selective vascular disruptive activity of DMXAA in an orthotopic HNC model. Further evaluation into its antitumor effects alone and in combination with other agents is warranted. 相似文献