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Even with all the recent technological improvements, cancer remains to be the disease with the highest impact on global health. Due to obviously disadvantages or limitations on traditional therapy, researchers are engaged to search for safely and effective methods in cancers’ therapy. Photothermal therapy (PTT) has been employed in treating cancers and several of other diseases. In this study, novel thermosensitive and targeting nanoparticle, C225-silane-F127/gold nanorod (C-SFGR) combined with PTT was investigated in EGFR-overexpressing xenografts mice model. For better light to heat transformation exposed with 808 nm near-infrared (NIR) laser, the diameter of thermosensitive C-SFGR was designed at about 120 nm. To address the biocompatibility, the viability of A549 cell line was greater than 80% under high concentrations of C-SFGR (1,000 μg/mL), indicating its low cytotoxicity. After intravenous injection of C-SFGR and combined with NIR treatment for 2 min in A549 bearing mice, tumors were almost completely shriveled after 2 weeks. For developing as theranostic agent, C-SFGR was then labeled with 67Ga, with radiochemical purity over 98%. These present results suggest that C-SFGR could be also applied as a SPECT-imaging agent and as an effective antitumor agent.

Background C-X-C motif chemokine receptor 4 (CXCR4) plays a prominent role in inflammation, atherosclerosis, and cancer biology. Therefore, CXCR4 represents a promising target for molecular imaging in cardiovascular diseases such as atherosclerosis and arterial wall injury. CXCR4 and its cognate ligand, stromal cell–derived factor 1α (SDF-1α), induced monocyte recruitment to the injured endothelium and subsequent plaque formation is the crucial progression of atherosclerosis. CXCR4 was been proved to be intensively expressed on monocytes/macrophage. [68Ga]-APD, based on the structure of CXCR4 antagonists TIQ-15, had designed by computer simulation as a PET tracer for imaging activated macrophages within the atherosclerotic lesions. The aim of this study was to evaluate the biological characteristics of [68Ga]-APD, and compared with the PET tracers targeting atherosclerotic lesion such as [18F]-FDG, [18F]-NaF, and [68Ga]-Pentixafor in apolipoprotein-E-deficient (ApoE−/−) mice. Results The specification and quality of APD was identified by Mass, NMR and HPLC. After being labeled with Ga-68 under acetate buffer (pH≒5.5), radiochemical purity was over 90% and stable for more than 4 hours in 37℃human serum. After being injected from tail vein on ApoE−/− atherosclerotic mice model, hydrophilic [68Ga]-APD was quickly eliminate from the kidney and bladder. [68Ga]-APD could accumulate in the atherosclerotic aorta site and CXCR4 expression organs. The highest target/background ratio (TBR) on atherosclerotic sites were 17.68 ± 0.71 (n = 3) on high-fat diet ApoE−/− mice for 12 weeks after [68Ga]-APD injection within 1 hour. However, [68Ga]-Pentixafor was only 2.06 ± 0.67 (n = 3) on the same mice model. Competitive study represented that CXCR4 antagonist AMD3465 could effectively block the uptake of [68Ga]-APD on the atherosclerotic site and CXCR4 expression organs. Comparing with [18F]-FDG and [18F]-NaF, [68Ga]-APD represented relatively better TBR and specificity on the imaging of atherosclerotic lesions. Conclusion In vivo evaluation of CXCR4 expression in ApoE−/− mice revealed the uptake of [68Ga]-APD mainly accumulated in the atherosclerotic aorta site. Moreover, the TBR of [68Ga]-APD was 8 times higher than [68Ga]-Pentixafor, a radiotracer targeting CXCR4 and under phase II clinical trial, indicating this novel tracer [68Ga]-APD is more feasible as a surrogate marker for inflammatory atherosclerosis.

// Kai-Lin Yang 1, 2, 3 , Cheng-Chung Huang 1 , Mau-Shin Chi 1 , Hsin-Chien Chiang 1 , Yu-Shan Wang 1 , Chien-Chung Hsia 4 , Gabor Andocs 5 , Hsin-Ell Wang 2 , Kwan-Hwa Chi 1, 2, 6 1 Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan 2 Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan 3 School of Medicine, Fu Jen Catholic University, New Taipei, Taiwan 4 Institute of Nuclear Energy Research, Taoyuan, Taiwan 5 Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan 6 Institute of Veterinary Clinical Science, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan Correspondence to: Kwan-Hwa Chi, email: M006565@ms.skh.org.tw Hsin-Ell Wang, email: hewang@ym.edu.tw Keywords: modulated electro-hyperthermia, conventional capacitive coupling hyperthermia, water bath, cytotoxicity, cell membrane Received: May 03, 2016 Accepted: August 11, 2016 Published: August 20, 2016 ABSTRACT Radiofrequency-induced hyperthermia (HT) treatments for cancer include conventional capacitive coupling hyperthermia (cCHT) and modulated electro-hyperthermia (mEHT). In this study, we directly compared these methods with regard to in vitro cytotoxicity and mechanisms of action under isothermal conditions. Hepatoma (HepG2) cells were exposed to HT treatment (42°C for 30 min) using mEHT, cCHT or a water bath. mEHT produced a much higher apoptosis rate (43.1% ± 5.8%) than cCHT (10.0% ± 0.6%), the water bath (8.4% ± 1.7%) or a 37°C control (6.6% ± 1.1%). The apoptosis-inducing effect of mEHT at 42°C was similar to that achieved with a water bath at 46°C. mEHT also increased expression of caspase-3, 8 and 9. All three hyperthermia methods increased intracellular heat shock protein 70 (Hsp70) levels, but only mEHT greatly increased the release of Hsp70 from cells. Calreticulin and E-cadherin levels in the cell membrane also increased after mEHT treatment, but not after cCHT or water bath. These results suggest that mEHT selectively deposits energy on the cell membrane and may be a useful treatment modality that targets cancer cell membranes.

Hypoxic-ischemic insult in newborns results in progressive neuronal loss. For neuroprotective therapy to be effective, it is important to identify high-risk neonates soon after birth. 99mTc-labeled imaging agent, Tc-99m-HL91, developed as a putative hypoxic reagent, has been reported to demonstrate increased uptake in ischemic myocardium. We hypothesized that Tc-99m-HL91 is sensitive for the early identification of hypoxic-ischemic injury in neonatal rat brains.Laboratory investigation.University research laboratory.Sprague-Dawley rat pups.Postnatal day-7 pups were divided into four groups: hypoxic-ischemia, hypoxia-only, ischemia-only, and controls. In the early (2 hrs), intermediate (20 hrs), and late (44 hrs) reoxygenation phases, Tc-99m-HL91 in vivo and ex vivo imaging and quantitative autoradiography were performed. Regions of interest were drawn to calculate the contrast ratio of Tc-99m-HL91 uptake between the ipsilateral and contralateral hemispheres. Pathology, cerebral blood flow, and blood-brain barrier damage were determined.After hypoxic-ischemia, there were very few pyknotic neurons in the early phase, many pyknotic neurons in the intermediate phase, and extensive neuronal loss in the late phase postreoxygenation. Blood-brain barrier damage occurred in the early phase, progressed in the intermediate phase, and became extensive in the late phase. The hypoxia-only and ischemia-only pups showed no neuronal or blood-brain barrier damage and had higher cerebral blood flow postreoxygenation compared with the hypoxia-ischemia pups. Regions of interest analysis of in vivo and ex vivo images and autoradiography revealed significantly higher Tc-99m-HL91 contrast ratio at early and intermediate phases, not late phase of hypoxic-ischemic group. Hypoxic-ischemia group had significantly higher contrast ratio values in the early and intermediate phases than the hypoxia-only and ischemia-only groups. A contrast ratio value of 0.15 in the early phase on postnatal day 7 had a sensitivity of 0.95 and specificity of 0.89 in detecting significant hypoxic-ischemic lesions on postnatal day 21.Tc-99m-HL91 uptake is sensitive for the early detection of hypoxic-ischemic injury in neonatal brains.

This study evaluated the tumor targeting and therapeutic efficacy of a novel theranostic agent (131)I-labeled immuno-gold-nanoparticle ((131)I-C225-AuNPs-PEG) for high epidermal growth factor receptor (EGFR)-expressed A549 human lung cancer. Confocal microscopy demonstrated the specific uptake of C225-AuNPs-PEG in A549 cells. (131)I-C225-AuNPs-PEG induced a significant reduction in cell viability, which was not observed when incubated with AuNPs-PEG and C225-AuNPs-PEG. MicroSPECT/CT imaging of tumor-bearing mice after intravenous injection of (123)I-C225-AuNPs-PEG revealed significant radioactivity retention in tumor suggested that (131)I-labeled C225-conjugated radioimmuno-gold-nanoparticles may provide a new approach of targeted imaging and therapy towards high EGFR-expressed cancers.

Aim 99mTc-HL91 (Prognox, GE-Healthcare) was the first nonnitro-aryl-based radiotracer for evaluating hypoxic fraction in neoplasm, stroke and myocardium infarction regions. However, the high hydrophilicity of 99mTc-HL91 might hamper its penetration into cells. In this study, we prepared a new ligand 4,4,11,11-tetramethyl- 5,10-diazatetradecane- 3,12-dionedioxime (HL91-ET) with higher lipophilicity but structurally similar compared with that of HL91. The chemical and biological characterizations of 99mTc-HL91-ET as a scintigraphic probe for hypoxia were performed with a stroke-bearing mouse model. Materials and Methods HL91-ET was synthesized and formulated with stannous chloride and buffer to afford kits. After mixing with 99mTc-pertechnetate, 99mTc-HL91-ET can be prepared in high yield and high radiochemical purity (both >96%). The partition coefficient of 99mTc-HL91-ET was determined in n-octanol/PBS system. Cellular uptake assays under normoxic and hypoxic conditions were performed in an oxygen-controlled CO2 incubator. Brain stroke in the mouse model was induced by the electrocautery of the middle cerebral artery. After intravenous injection of 99mTc-HL91-ET into the Balb/c mouse suffering brain stroke, small-animal SPECT images were acquired at designated time points and autoradiography of the brain slides was conducted. Parallel studies of 99mTc-HL91 were also conducted at the same conditions for comparison. Results The higher partition coefficient of 99mTc-HL91-ET (0.294±0.007) indicated higher lipophlicity compared with that of 99mTc-HL91 (0.089±0.005). The 99mTc-HL91-ET preparation was stable at ambient temperature for 24 h. Cellular uptake assay showed that 99mTc-HL91-ET was less selectively retained in hypoxic cells than 99mTc-HL91. The target-to-normal brain ratios derived from the autoradiograms of the brains of stroke mice were 1.31±0.02 and 17.47±0.10 (n=3), respectively, at 2 h post injection of 99mTc-HL91-ET and 99mTc-HL91. Conclusions This study revealed that 99mTc-HL91-ET, though with higher lipophilicity than 99mTc-HL91, did not suggest better specific accumulation in hypoxic cells or tissues than 99mTc-HL91. The uptake mechanism of 99mTc-HL91 was at least not solely by passive diffusion. Lipophilicity should not be the major consideration in designing HL91-derivatives for hypoxia imaging.

Objectives Tumor growth beyond the region where vascular oxygen can reach creates a hypoxic domain. In this study, BnAO, a ligand that had been labeled with 99m Tc-pertechnetate for hypoxia imaging, was conjugated with 2-nitroimidazole to give 3,3,10,10-tetramethyl-1-(2-nitro-1H-imidazo-1-y1)-4,9-diazadodecane-2,11- dionedioxime (BnAO-NI) as a potential ligand for hypoxia detection. Pentoxifylline is a peripheral vasodilator and has been used as a radiosensitizer in tumor radiotherapy. 99m Tc-BnAO-NI/SPECT was applied to noninvasively assess the pharmacological effect of pentoxifylline in reducing tumor hypoxia in vivo. Methods BnAO-NI was synthesized and formulated with methylene diphosphonate (MDP), stannous chloride and carbonate buffer to afford kits. After mixing with 99m Tc-pertechnetate, 99m Tc-BnAO-NI injection can be readily prepared. The partition coefficient, radiochemical purity and in vitro stability were determined. Cellular uptake of radiotracers in KHT cells under hypoxia was conducted in a CO 2 incubator at 37 °C under hypoxia or normoxia. A biodistribution study after intravenous injection of 99m Tc-BnAO-NI in KHT sarcoma-implanted C3H mice was performed. The effect of pentoxifylline (100 mg/kg) on reducing tumor hypoxia was also studied. Results The radiochemical purity (RCP) of the 99m Tc-BnAO-NI preparation was greater than 96% and stable at ambient temperature for 24 h (RCP>90%). The accumulation of 99m Tc-BnAO-NI and 99m Tc-BnAO in KHT cells under hypoxia were 3.57 and 4.13-fold higher than those under normoxic environment, indicating unambiguous oxygen-dependent uptakes of these two probes. The distribution of 99m Tc-BnAO-NI in KHT sarcoma-bearing mice revealed rapid clearance from the blood circulation. The tumor uptake peaked at 2 h post-injection (0.32±0.05%ID/g) with tumor-to-blood and tumor-to-muscle ratios of 10.32 and 3.96, respectively. The effect of pentoxifylline on the tumor blood perfusion was obvious. The tumor-to-muscle ratios at 2 h post-injection of 99m Tc-BnAO-NI with and without pentoxifylline pretreatment were 1.67±0.38 and 2.59±0.25, respectively ( p =0.025, n =3). Conclusion This study demonstrates that 99m Tc-BnAO-NI is a hypoxia-sensitive radio probe for monitoring hypoxic regions in a malignant neoplasm. However, 99m Tc-BnAO-NI, though with higher lipophilicity than 99m Tc-BnAO, did not achieve better specific accumulation in hypoxic tissues. 99m Tc-BnAO-NI/SPECT could be applied in clinics to noninvasively evaluate the feasibility of using pentoxifylline as a radiosensitizer by reducing tumor hypoxia in vivo.

Purpose: Several studies have reported significant renal toxicity after the use of a high dose of90Y-DOTATOC. Thus, renal protection is necessary in treatments with90Y-DOTA Tyr3-octroetide (DOTATOC). The infusion of certain positively charged amino acids has been shown to effectively reduce renal uptake of DOTATOC. In this study, we compared the effectiveness of three kinds of amino acids, D-lysine (lysine),L-arginine (arginine) and histidine, on renal protection in healthy rats and tried to determine which one was the most effective.Methods: Twenty SD healthy male rats were divided into 4 groups: lysine, histidine, arginine, and control. The rats were injected with a dose of 400 mg/kg of amono acid or 2 ml of phosphate-buffered saline (PBS) (as control) intraperitoneally. All rats were sacrificed at 4 hrs after the injection of 1 MBq111In-DOTATOC. Samples of the kidney were taken and weighed carefully. The counts of radioactivity were measured by a gamma counter and renal concentrations were calculated and expressed as percent injected dose per gram (% ID/g).Results: The renal uptake of111In-DOTATOC was significantly lower for all three kinds of amino acids when compared to the control group. The renal uptake of111In-DOTATOC in the lysine group was significantly lower than those in the histidine and arginine groups. The renal uptake of111In-DOTATOC in the histidine group was lower than that in the arginine group, but no statistical difference was noted.Conclusion: Among these three amino acids, lysine had the best reduction rate of renal uptake of DOTATOC. Histidine was more effective than arginine but no statistical difference was noted.

111In-DTPA octreotide (DTPAOC) has been used for detecting somatostatin receptor positive tumor for years. In-111 DOTA-Tyr3-octreotide (DOTATOC) is newly developed for diagnostic and therapeutic purposes. In this study, we compared the biodistribution and tumor uptake ratio after injection of In-111 DTPAOC and In-111 DOTATOC in rats. Twelve rats bearing pancreatic tumors were divided into two groups: six rats were sacrificed at 4 hr after injection of 3.7 MBq of In-111 DTPAOC and another 6 rats were sacrificed at the same time after injection of 3.7 MBq of In-111 DOTATOC. Samples of various organs were obtained and counted to calculate the tissue concentration. In addition, 12 rats bearing pancreatic tumors were scanned at 4, 24, and 48 hr after injection of 37 MBq of In-111 DTPAOC or In-111 DOTATOC. The tumor uptake ratios (T/N ratio) were calculated. The biodistribution data showed that the activity in the tumor as well as in the kidney was significantly higher in the In-111 DOTATOC group than in the In-111 DTPAOC group, although both radiopharmaceuticals had the expected high affinity to the tumor. The T/N ratios in the In-111 DOTATOC group were also significantly higher than those in the In-111 DTPAOC group at 24 hr after injection. We conclude that In-111 DOTATOC showed lower clearance than In-111 DTPAOC in the rats bearing pancreatic tumors, although both of these radiopharmaceuticals showed expected high tumor uptake.

Gold nanoparticles (AuNPs) are widely applied to the diagnosis and treatment of cancer and can be modified to contain target-specific ligands via gold-thiolate bonding. This study investigated the pharmacokinetics and microdistribution of antibody-mediated active targeting gold nanoparticles in mice with subcutaneous lung carcinoma. We conjugated AuNPs with cetuximab (C225), an antibody-targeting epidermal growth factor receptor (EGFR), and then labeled with In-111, which created EGFR-targeted AuNPs. In vitro studies showed that after a 2 h incubation, the uptake of C225-conjugated AuNPs in high EGFR-expression A549 cells was 14.9-fold higher than that of PEGylated AuNPs; furthermore, uptake was also higher at 3.8-fold when MCF7 cells with lower EGFR-expression were used. MicroSPECT/CT imaging and a biodistribution study conducted by using a A549 tumor xenograft mouse model provided evidence of elevated uptake of the C225-conjugated AuNPs into the tumor cells as a result of active targeting. Moreover, the microdistribution of PEGylated AuNPs revealed that a large portion of AuNPs remained in the tumor interstitium, whereas the C225-conjugated AuNPs displayed enhanced internalization via antibody-mediated endocytosis. Our findings suggest that the anti-EGFR antibody-conjugated AuNPs are likely to be a plausible nano-sized vehicle for drug delivery to EGFR-expressing tumors.