Melatonin decreases breast cancer metastasis by modulating Rho-associated kinase protein-1 expression.

The occurrence of metastasis, an important breast cancer prognostic factor, depends on cell migration/invasion mechanisms, which can be controlled by regulatory and effector molecules such as Rho-associated kinase protein (ROCK-1). Increased expression of this protein promotes tumor growth and metastasis, which can be restricted by ROCK-1 inhibitors. Melatonin has shown oncostatic, antimetastatic, and anti-angiogenic effects and can modulate ROCK-1 expression. Metastatic and nonmetastatic breast cancer cell lines were treated with melatonin as well as with specific ROCK-1 inhibitor (Y27632). Cell viability, cell migration/invasion, and ROCK-1 gene expression and protein expression were determined in vitro. In vivo lung metastasis study was performed using female athymic nude mice treated with either melatonin or Y27832 for 2 and 5 wk. The metastases were evaluated by X-ray computed tomography and single photon emission computed tomography (SPECT) and by immunohistochemistry for ROCK-1 and cytokeratin proteins. Melatonin and Y27632 treatments reduced cell viability and invasion/migration of both cell lines and decreased ROCK-1 gene expression in metastatic cells and protein expression in nonmetastatic cell line. The numbers of 'hot' spots (lung metastasis) identified by SPECT images were significantly lower in treated groups. ROCK-1 protein expression also was decreased in metastatic foci of treated groups. Melatonin has shown to be effective in controlling metastatic breast cancer in vitro and in vivo, not only via inhibition of the proliferation of tumor cells but also through direct antagonism of metastatic mechanism of cells rendered by ROCK-1 inhibition. When Y27632 was used, the effects were similar to those found with melatonin treatment.

Role of reactive oxygen species (ROS) in CDDO-Me-mediated growth inhibition and apoptosis in colorectal cancer cells.

CDDO-Me, an oleanane synthetic triterpenoid has shown strong antitumorigeic activity towards diverse cancer cell types including colorectal cancer cells. In the present study, we investigated the role of free radicals in the growth inhibitory and apoptosis-inducing activity of CDDO-Me in colorectal cancer cells lines. Results demonstrated that CDDO-Me potently inhibited the growth of colorectal cancer cells and pretreatment of cancer cells with small-molecule antioxidant N-acetylcysteine (NAC) completely blocked the growth inhibitory activity of CDDO-Me. CDDO-Me caused the generation of reactive oxygen species, which was inhibited by NAC and mitochondrial chain 1 complex inhibitors DPI and rotenone. CDDO-Me induced apoptosis as demonstrated by the cleavage of PARP-1, activation of procaspases -3, -8, and -9 and mitochondrial depolarization and NAC blocked the activation of these apoptosis related processes. Furthermore, induction of apoptosis by CDDO-Me was associated with the inhibition of antiapoptotic/ prosurvival Akt, mTOR and NF-kappaB signaling proteins and the inhibition of these signaling molecules was blocked by NAG. Together these studies provided evidence that CDDO-Me is a potent anticancer agent, which imparts growth inhibition and apoptosis in colorectal cancer cells through the generation of free radicals.

Changes in the tumor microenvironment and outcome for TME-targeting therapy in glioblastoma: A pilot study.

Glioblastoma (GBM) is a hypervascular and aggressive primary malignant tumor of the central nervous system. Recent investigations showed that traditional therapies along with antiangiogenic therapies failed due to the development of post-therapy resistance and recurrence. Previous investigations showed that there were changes in the cellular and metabolic compositions in the tumor microenvironment (TME). It can be said that tumor cell-directed therapies are ineffective and rethinking is needed how to treat GBM. It is hypothesized that the composition of TME-associated cells will be different based on the therapy and therapeutic agents, and TME-targeting therapy will be better to decrease recurrence and improve survival. Therefore, the purpose of this study is to determine the changes in the TME in respect of T-cell population, M1 and M2 macrophage polarization status, and MDSC population following different treatments in a syngeneic model of GBM. In addition to these parameters, tumor growth and survival were also studied following different treatments. The results showed that changes in the TME-associated cells were dependent on the therapeutic agents, and the TME-targeting therapy improved the survival of the GBM bearing animals. The current GBM therapies should be revisited to add agents to prevent the accumulation of bone marrow-derived cells in the TME or to prevent the effect of immune-suppressive myeloid cells in causing alternative neovascularization, the revival of glioma stem cells, and recurrence. Instead of concurrent therapy, a sequential strategy would be better to target TME-associated cells.

The innate immune receptor TREM-1 promotes liver injury and fibrosis.

Inflammation occurs in all tissues in response to injury or stress and is the key process underlying hepatic fibrogenesis. Targeting chronic and uncontrolled inflammation is one strategy to prevent liver injury and fibrosis progression. Here, we demonstrate that triggering receptor expressed on myeloid cells 1 (TREM-1), an amplifier of inflammation, promotes liver disease by intensifying hepatic inflammation and fibrosis. In the liver, TREM-1 expression was limited to liver macrophages and monocytes and was highly upregulated on Kupffer cells, circulating monocytes, and monocyte-derived macrophages in a mouse model of chronic liver injury and fibrosis induced by carbon tetrachloride (CCl4) administration. TREM-1 signaling promoted proinflammatory cytokine production and mobilization of inflammatory cells to the site of injury. Deletion of Trem1 reduced liver injury, inflammatory cell infiltration, and fibrogenesis. Reconstitution of Trem1-deficient mice with Trem1-sufficient Kupffer cells restored the recruitment of inflammatory monocytes and the severity of liver injury. Markedly increased infiltration of liver fibrotic areas with TREM-1-positive Kupffer cells and monocytes/macrophages was found in patients with hepatic fibrosis. Our data support a role of TREM-1 in liver injury and hepatic fibrogenesis and suggest that TREM-1 is a master regulator of Kupffer cell activation, which escalates chronic liver inflammatory responses, activates hepatic stellate cells, and reveals a mechanism of promotion of liver fibrosis.

Giant Magnetic Heat Induction of Magnesium-Doped γ-Fe2 O3 Superparamagnetic Nanoparticles for Completely Killing Tumors.

Magnetic fluid hyperthermia has been recently considered as a Renaissance of cancer treatment modality due to its remarkably low side effects and high treatment efficacy compared to conventional chemotheraphy or radiotheraphy. However, insufficient AC induction heating power at a biological safe range of AC magnetic field (Happl ·fappl < 3.0-5.0 × 109 A m-1 s-1 ), and highly required biocompatibility of superparamagnetic nanoparticle (SPNP) hyperthermia agents are still remained as critical challenges for successful clinical hyperthermia applications. Here, newly developed highly biocompatible magnesium shallow doped γ-Fe2 O3 (Mg0.13 -γFe2 O3 ) SPNPs with exceptionally high intrinsic loss power (ILP) in a range of 14 nH m2 kg-1 , which is an ≈100 times higher than that of commercial Fe3 O4 (Feridex, ILP = 0.15 nH m2 kg-1 ) at Happl ·fappl = 1.23 × 109 A m-1 s-1 are reported. The significantly enhanced heat induction characteristics of Mg0.13 -γFe2 O3 are primarily due to the dramatically enhanced out-of-phase magnetic susceptibility and magnetically tailored AC/DC magnetic softness resulted from the systematically controlled Mg2+ cations distribution and concentrations in octahedral site Fe vacancies of γ-Fe2 O3 instead of well-known Fe3 O4 SPNPs. In vitro and in vivo magnetic hyperthermia studies using Mg0.13 -γFe2 O3 nanofluids are conducted to estimate bioavailability and biofeasibility. Mg0.13 -γFe2 O3 nanofluids show promising hyperthermia effects to completely kill the tumors.

Perfusion CT investigation of chronic internal carotid artery occlusion: comparison with SPECT.

This study investigated the usefulness of perfusion computed tomography (CT) for the evaluation of patients with chronic internal carotid artery (ICA) occlusion by comparing the findings with those of iodine-123 iodoamphetamine ([(123)I]IMP) single photon emission computed tomography (SPECT). Twenty five patients with chronic ICA occlusion were investigated on the same day by perfusion CT to measure the cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transient time (MTT), and [(123)I]IMP SPECT to measure the regional CBF, significant correlations were observed between regional CBF measured by SPECT and CBF measured by perfusion CT (r = 0.659, R(2) = 0.434, p < 0.001), regional CBF and CBV (r = -0.406, R(2) = 0.165, p < 0.001) and regional CBF and MTT (r = -0.592, R(2) = 0.350, p < 0.001). Significant correlations were also observed between CBF and CBV (r = -0.153, R(2) = 0.023, p < 0.001), CBF and MTT (r = -0.580, R(2) = 0.337, p < 0.001) and MTT and CBV (r = 0.763, R(2) = 0.582, p < 0.001). Perfusion CT is useful to evaluate the hemodynamic state of patients with chronic major cerebral artery occlusive disorders.

Fluorescent magnetic iron oxide nanoparticles for cardiac precursor cell selection from stromal vascular fraction and optimization for magnetic resonance imaging.

Fluorescent magnetic iron oxide nanoparticles have been used to label cells for imaging as well as for therapeutic purposes. The purpose of this study was to modify the approach to develop a nanoprobe for cell selection and imaging with a direct therapeutic translational focus. The approach involves physical coincubation and adsorption of superparamagnetic iron oxide nanoparticle-polyethylene glycol (SPION-PEG) complexes with a monoclonal antibody (mAb) or a set of antibodies. Flow cytometry, confocal laser scanning microscopy, transmission electron microscopy, iron staining, and magnetic resonance imaging were used to assess cell viability, function, and labeling efficiency. This process has been validated by selecting adipose tissue-derived cardiac progenitor cells from the stromal vascular fraction using signal regulatory protein alpha (SIRPA)/kinase domain receptor (KDR) mAbs. These markers were chosen because of their sustained expression during cardiomyocyte differentiation. Sorting of cells positive for SIRPA and KDR allowed the enrichment of cardiac progenitors with 90% troponin-I positivity in differentiation cultures. SPION labeled cardiac progenitor cells (1×10(5) cells) was mixed with gel and used for 3T magnetic resonance imaging at a concentration, as low as 12.5 µg of iron. The toxicity assays, at cellular and molecular levels, did not show any detrimental effects of SPION. Our study has the potential to achieve moderate to high specific cell selection for the dual purpose of imaging and therapy.

Quantitative measurement of regional cerebral blood flow with flow-sensitive alternating inversion recovery imaging: comparison with [iodine 123]-iodoamphetamin single photon emission CT.

BACKGROUND AND PURPOSE: Flow-sensitive alternating inversion recovery (FAIR) MR imaging is a technique for depicting cerebral perfusion without contrast enhancement. Our purpose was to determine whether quantification at FAIR imaging can be used to assess regional cerebral blood flow (rCBF) in a manner similar to [iodine 123]-iodoamphetamin ((123)I-IMP) single photon emission CT (SPECT). METHODS: Nine patients with internal carotid or major cerebral arterial stenosis underwent (123)I-IMP SPECT and FAIR imaging (single section, different TIs, 1.5 T) at rest and after acetazolamide (Diamox) stress. FAIR and (123)I-IMP rCBF values were compared and correlated. Receiver operating characteristic analysis was conducted to detect hypoperfused segments on FAIR images. RESULTS: rCBF values of normally perfused segments were 41.53 and 51.91 mL/100 g/min for pre- and post-acetazolamide (123)I-IMP studies, respectively. Corresponding values for pre- and post-acetazolamide FAIR images, respectively, were 46.64 and 59.60 mL/100 g/min with a TI of 1200 milliseconds and 53.23 and 68.17 mL/100 g/min with a TI of 1400 milliseconds. (123)I-IMP and FAIR results were significantly correlated, with both pre- and post-acetazolamide images. Sensitivity (86%) in detecting hypoperfused segments was significantly higher with post-acetazolamide images (TI, 1400 milliseconds), and specificity (82-85%) and accuracy (80-82%) were higher with all pre- and post-acetazolamide images (all TIs). CONCLUSIONS: The significant correlation, high specificity and accuracy in detecting hypoperfused segments, similar increases in flow on both post-acetazolamide images, and absence of the need for contrast enhancement suggest that FAIR imaging, like nuclear medicine study, is complementary to routine MR imaging in the assessment of cerebral perfusion.

Velocity-coded colour magnetic resonance angiography and perfusion-weighted magnetic resonance imaging for the evaluation of extracranial-to-intracranial arterial bypass surgery.

BACKGROUND AND PURPOSE: Velocity-coded colour magnetic resonance angiography (VCCMRA) and perfusion magnetic resonance imaging (pMRI) were evaluated as methods for investigating the efficacy of extracranial-to-intracranial arterial bypass (EC-IC bypass) by comparing the findings of VCCMRA and those of cerebral angiography and by measuring the improvement ratio after EC-IC bypass by pMRI compared to that by single photon emission computed tomography (SPECT) using the autoradiographic technique. METHODS: Thirteen patients who underwent VCCMRA, angiography, SPECT, and pMRI before and after surgery were analyzed. Findings of VCCMRA were compared to those of angiography. Improvement ratio was calculated compared to the cerebellum for cerebral blood volume, mean transit time (MTT), and regional cerebral blood flow (rCBF) as measured by pMRI and quantitative SPECT. RESULTS: Findings of VCCMRA were in good agreement with those of angiography and clearly showed the direction of bypass flow. No statistically significant correlation was observed between the improvement ratios in CBF in the hemisphere and middle cerebral artery territory on the surgical and non-surgical sides and in rCBF in the same regions of interest (ROIs) (r=-0.574, 0.09). However, a statistically significant correlation was observed between the cerebrovascular reserve capacity (CVRC) in the hemisphere on the surgical side and in MTT in the same ROIs (r=0.955, P<0.001). CONCLUSION: VCCMRA may clearly show the direction of flow in the EC-IC bypass. MIT measured by pMRI may indicate the postoperative state of CVRC. These techniques could replace angiography and positron emission tomography or SPECT in patients undergoing EC-IC bypass.

Differentiating treatment-induced necrosis from recurrent/progressive brain tumor using nonmodel-based semiquantitative indices derived from dynamic contrast-enhanced T1-weighted MR perfusion.

Differentiating treatment-induced necrosis (TIN) from recurrent/progressive tumor (RPT) in brain tumor patients using conventional morphologic imaging features is a very challenging task. Functional imaging techniques also offer moderate success due to the complexity of the tissue microenvironment and the inherent limitation of the various modalities and techniques. The purpose of this retrospective study was to assess the utility of nonmodel-based semiquantitative indices derived from dynamic contrast-enhanced T1-weighted MR perfusion (DCET1MRP) in differentiating TIN from RPT. Twenty-nine patients with previously treated brain tumors who showed recurrent or progressive enhancing lesion on follow-up MRI underwent DCET1MRP. Another 8 patients with treatment-naive high-grade gliomas who also underwent DCET1MRP were included as the control group. Semiquantitative indices derived from DCET1MRP included maximum slope of enhancement in initial vascular phase (MSIVP), normalized MSIVP (nMSIVP), normalized slope of delayed equilibrium phase (nSDEP), and initial area under the time-intensity curve (IAUC) at 60 and 120 s (IAUC(60) and IAUC(120)) obtained from the enhancement curve. There was a statistically significant difference between the 2 groups (P < .01), with the RPT group showing higher MSIVP (15.78 vs 8.06), nMSIVP (0.046 vs 0.028), nIAUC(60) (33.07 vs 6.44), and nIAUC(120) (80.14 vs 65.55) compared with the TIN group. nSDEP was significantly lower in the RPT group (7.20 × 10(-5) vs 15.35 × 10(-5)) compared with the TIN group. Analysis of the receiver-operating-characteristic curve showed nMSIVP to be the best single predictor of RPT, with very high (95%) sensitivity and high (78%) specificity. Thus, nonmodel-based semiquantitative indices derived from DCET1MRP that are relatively easy to derive and do not require a complex model-based approach may aid in differentiating RPT from TIN and can be used as robust noninvasive imaging biomarkers.

Cytotoxic T-cells as imaging probes for detecting glioma.

Tumor vaccination using tumor-associated antigen-primed dendritic cells (DCs) is in clinical trials. Investigators are using patients' own immune systems to activate T-cells against recurrent or metastatic tumors. Following vaccination of DCs or attenuated tumor cells, clinical as well as radiological improvements have been noted due to migration and accumulation of cytotoxic T-cells (CTLs). CTLs mediated tumor cell killing resulted in extended survival in clinical trails and in preclinical models. Besides administration of primed DCs or attenuated or killed tumors cells to initiate the generation of CTLs, investigators have started making genetically altered T-cells (CTLs) to target specific tumors and showed in vivo migration and accumulation in the implanted or recurrent tumors using different imaging modalities. Our groups have also showed the utilization of both in vivo and in vitro techniques to make CTLs against glioma and used them as imaging probes to determine the sites of tumors. In this short review, the current status of vaccination therapy against glioma and utilization of CTLs as in vivo imaging probes to determine the sites of tumors and differentiate recurrent glioma from radiation necrosis will be discussed.

Comparison of transfection agents in forming complexes with ferumoxides, cell labeling efficiency, and cellular viability.

By complexing ferumoxides or superparamagnetic iron oxide (SPIO) to transfection agents (TAs), it is possible to magnetically label mammalian cells. There has been no systematic study comparing TAs complexed to SPIO as far as cell labeling efficiency and viability. This study investigates the toxicity and labeling efficiency at various doses of FEs complexed to different TAs in mammalian cells. Different classes of TAs were used, such as polycationic amines, dendrimers, and lipid-based agents. Cellular toxicity was measured using doses of TAs from 1 to 50 microg/mL in incubation media. Iron incorporation efficiency was measured by combining various amounts of FEs and different doses of TAs. Lipofectamine2000 showed toxicity at lowest dose (1 microg/mL), whereas FuGENE6 and low molecular weight poly-L-lysine (PLL) showed the least toxicity. SPIO labeling efficiency was similar with high-molecular-weight PLL (388.1 kDa) and superfect, whereas FuGENE6 and low-molecular-weight PLL were inefficient in labeling cells. Concentrations of 25 to 50 microg/mL of FEs complexed to TAs in media resulted in sufficient endocytosis of the SPIO into endosomes to detect cells on cellular magnetic resonance imaging.

Optimal inversion time for acquiring flow-sensitive alternating inversion recovery images to quantify regional cerebral blood flow.

The purpose of this study was to correlate regional cerebral blood flow (rCBF) measured by I-123-IMP and flow-sensitive alternating inversion recovery (FAIR) studies with different inversion time (TI) values to find out the optimum TI that gives comparable rCBF and images on FAIR study. Nine patients with symptoms and signs of internal carotid or major cerebral arterial stenosis were enrolled in this study. Both I-123-IMP single photon emission computed tomography (SPECT) and FAIR images were acquired in all patients. Single-slice FAIR images (with different TI values) were acquired using a 1.5-T MRI unit. The rCBF was calculated from all I-123-IMP and FAIR images. Receiver operating characteristics (ROC) analysis was performed to detect hypoperfused segments on FAIR images. The rCBF calculated from FAIR and I-123-IMP studies were compared and correlated with each other. The ROC analysis showed no significant differences among the readers or TI values, but a trend of higher sensitivity, specificity, and accuracy was observed with TI of 1400 ms. The rCBF values of FAIR and I-123-IMP studies significantly correlated with each other. The FAIR images with TI value of 1400 ms gave more comparable CBF. A TI value of 1400 ms might be optimum for 1.5-T MR strength to get high quality FAIR images and comparable CBF.