Evaluation of labelling conditions,quality control and biodistribution study of 99mTc-5-aminolevulinic acid (5-ALA): a potential liver imaging agent

Labelling of 5-aminolevulinic acid (5-ALA) with ^99mTc was achieved by using SnCl₂·2H₂O as reducing agent. Radiochemical purity and labelling efficiency was determined by instant thin layer chromatography/paper chromatography. Efficiency of labelling was dependent on many parameters such as amount of ligand, reducing agent, pH, and time of incubation. ^99mTc labelled 5-ALA remained stable for 24 h in human serum. Tissue biodistribution of ^99mTc-5-ALA was evaluated in Sprague–Dawley rats. Biodistribution study (% ID/g) in rats revealed that ^99mTc-5-ALA was accumulated significantly in liver, spleen, stomach and intestine after half hour, 4 and 24 h. Significant activity was noted in bladder and urine at 4 h. High liver uptake of ^99mTc-5-ALA makes it a promising liver imaging agent.     

应用99mTc标记法测定半乳糖-聚羟乙谷氨酰胺在小鼠体内的生物分布

采用二环己基碳二亚胺(DCC)作缩合剂，4-二甲基氨基吡啶(DMPA)作催化剂，将双官能团螯合剂二亚乙基三胺五乙酸(DTPA)，键合在化学合成的聚氨基酸材料聚羟乙谷氨酰胺(PHEG)及拟糖蛋白半乳糖-聚羟乙谷氨酰胺(GAL—PHEG)上，用同位素^99mTc对其进行标记，将Tc-PHEG和Tc-GAL-PHEG注射到小鼠体内，研究其在小鼠心、肝、胃、肾等器官中的生物分布；研究结果表明Tc-GAL-PHEC在肝中的含量高于Tc-PHEG。且随着糖基含量的增大在肝中的含量有所增加。     

Synthesis, radiolabeling and biological evaluation of propylene amine oxime complexes containing nitrotriazoles as hypoxia markers

Two propylene amine oxime (PnAO) complexes, 1, containing a 3-nitro-1,2,4-triazole and 2, containing two 3-nitro-1,2,4-triazoles, were synthesized and radiolabeled with (99m)Tc in high labeling yields. Cellular uptakes of (99m)Tc-1 and (99m)Tc-2 were tested using a S180 cells line. Under anoxic conditions, the cellular uptakes of (99m)Tc-1 and (99m)Tc-2 were 33.7 ± 0.2% and 35.0 ± 0.7% at 4 h, whereas the normoxic uptakes of the two complexes were 6.0 ± 1.6% and 4.6 ± 0.9%, respectively. Both (99m)Tc-1 and (99m)Tc-2 displayed significant anoxic/normoxic differentials. The cellular uptakes were highly dependent on oxygen and temperature. Biodistribution studies revealed that both (99m)Tc-1 and (99m)Tc-2 showed a selective localization in tumor and slow clearance from it. At 4 h, the tumor-to-muscle ratios (T/M) were 3.79 for (99m)Tc-1 and 4.58 for (99m)Tc-2. These results suggested that (99m)Tc-labeled PnAO complexes (99m)Tc-1 and (99m)Tc-2 might serve as novel hypoxia markers. By introducing a second nitrotriazole redox center, the hypoxic accumulation of the marker was slightly enhanced.     

Design,synthesis and anti-proliferative effects in tumor cells of new combretastatin A-4 analogs

A total of 11 novel combretastatin A-4(CA-4) analogs were designed, synthesized, and evaluated for the anti-proliferative effects in tumor cells. The compounds represent four structural classes:(i)hydrogenated derivatives,(ii) ethoxyl derivatives,(iii) amino derivatives and(iv) pro-drugs. Biological evaluations demonstrate that multiple structural features control the biological potency. Three of the compounds, sit-1, sit-2 and sit-3, have potent anti-proliferative activity against multiple cancer cell lines. Their pro-drugs were synthesized to increase water solubility. Structure–activity relationship study and Surflex-Docking were studied in this paper. These results will be useful for the design of new CA-4 analogs that are structurally related to the SAR study.     

99mTc-EC: A new renal functional imaging agent

The biological behavior of Technetium-99m-L,L-Ethylenedicysteine (Tc-99m-EC)was compared with that of Technetium-99m-Mercaftoacetyltriglycine (Tc-99m-MAG3) and Iodine-131-hippuran (1131-OIH) in mice and rabbits. Tc-99m-EC showed a more rapid urinary excretion and less retention in kidney, liver, intestines and blood in comparison to Tc-99m-MAG3 and I-131-OIH. Urinary excretion decreased after probenecid treatment, indicating active tubular transport. In human bodies, the renal scintigraphy with Tc-99m-EC, Tc-99m-MAG3 and Tc-99m-DTPA were comparable. The promising results of the animal and human studies suggest that Tc-99m-EC may be a useful alternative to Tc-99m-MAG3 and I-131-OIH for renal functional studies.     

Direct labelling of anti-gastric cancer monoclonal antibody 3H11 with99mTc

Monoclonal antibody 3H11 was labelled with^99mTc by modified Schwartz method. The antibody was incubated in a glass test tube at room temperature for 30min with a 1000-fold molar excess of 2-mercaptoethanol. The mean labelling efficiency of 3H11 with^99mTc was more than 95%. The immuonreactivity of^99mTc-3H11 was more than 80% by ELISA's method. Competetion results in vitro and HPLC analysis showed that^99mTc was combined at the high affinity sites of antibody. The biodistribution in nude mice bearing 823 gastric cancer xenograpfts showed that the radioactivity in tumor at 24h postinjection was the highest except for that in kidney. The tumor uptake was 8.98±2.42% i.d/g. The ratio of tumor to blood was over 1.5 and that of tumor to liver was more than 2.5 at 24h post-injection. The tumor was clearly imaged at 22h postinjection. The inital clinical results showed that^99mTc-3H11 was stable in vivo and was good located at the lesion sites.     

Utilization of cyanoacetohydrazide and 2-(1,3-dioxoisoindolin-2-yl) acetyl chloride in the synthesis of some novel anti-proliferative heterocyclic compounds

Abstract

Owing to its high reactivity and commercial availability, 2-cyanoacetohydrazide can be utilized as a versatile and appropriate intermediate for synthesis of a broad variety of heterocyclic compounds. Thus, 2-cyanoacetohydrazide and 2-(1,3-dioxoisoindolin-2-yl) acetyl chloride were used as starting materials for construction of new heterocyclic compounds bearing 1,3-dioxoisoindoline moiety. The newly synthesized compounds were recognized by elemental analyses and spectral data (IR, ¹H-NMR, and ¹³C-NMR spectra). The synthesized compounds were screened for their anti-proliferative activity against two human epithelial cell lines; breast (MCF-7) and liver (HepG2) as well as to normal fibroblasts (WI-38). The data showed distinctly that compounds 1 and 12 presented promising in-vitro anti-proliferative activity against two cell lines (MCF-7 and HepG2) without harming normal fibroblasts.     

N(4)-tolyl-2-benzoylpyridine-derived thiosemicarbazones and their palladium(II) and platinum(II) complexes: Cytotoxicity against human solid tumor cells

Complexes [Pt(2Bz4oT)Cl], [Pt(2Bz4mT)Cl], and [Pt(2Bz4pT)Cl] were prepared with N(4)-ortho-(H2Bz4oT), N(4)-meta-(H2Bz4mT), and N(4)-para-(H2Bz4pT) tolyl-2-benzoylpyridine-derived thiosemicarbazones. The thiosemicarbazones exhibited moderate anti-proliferative activity against HepG2 (hepatoma) and UACC-62 (melanoma) cancer cell lines, but showed high anti-proliferative effect against A431 (epithelial carcinoma) cancer cell lines. Upon coordination to platinum(II) the anti-proliferative activity decreases in all cases. The cytotoxicity of the previously prepared palladium(II) analogues [Pd(2Bz4oT)Cl], [Pd(2Bz4mT)Cl], and [Pd(2Bz4pT)Cl] was also investigated. As in the case of the platinum(II) complexes, coordination to palladium(II) did not lead to activity improvement. Investigations on the mechanism of cytotoxic action against A431 cells revealed that [Pd(2Bz4oT)Cl] induced DNA fragmentation and apoptosis while H2Bz4oT did not present this effect. The high anti-proliferative effect of the thiosemicarbazones and [Pd(2Bz4oT)Cl] against A431 cells, together with the pro-apoptotic effect of [Pd(2Bz4oT)Cl] suggests that these compounds have potential as chemotherapeutic drug candidates.     

An equilibrium analysis of the aqueous H+-MoO4(2-)-(HP)O(3)2- and H+-MoO4(2-)-(HP)O(3)2--HPO4(2-) systems

The speciation in the phosphitomolybdate system, H+-MoO4(2-)-(HP)O(3)2-, has been determined from combined potentiometric and 31P NMR measurements in 0.600 M Na(Cl) medium at 298(1) K. Potentiometric titration data were collected in the ranges 2.5<-log[H+]<6.2, 40.0相似文献   

Synthesis and biological evaluation of novel technetium-99m-labeled HYNIC-d-glucose as a potential tumor imaging agent

A conjugate of 6-hydrazinopyridine-3-carboxylic acid (HYNIC) with the d-Glucosamine Hydrochloride (DG) was synthesized though a multiple-step reaction. HYNIC-DG could be labeled successfully and efficiently with ^99mTc using N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine (tricine) and ethylenediamine-N,N′-diacetic acid (EDDA) or tricine and triphenylphosphine-3,3′,3″-trisulfonic acid trisodium salt (TPPTS) as co-ligands to form two ^99mTc-HYNIC-DG complexes ^99mTc-(t/E)HYNIC-DG and ^99mTc-(t/T)HYNIC-DG in high yields (>95 %). The partition coefficient and electrophoresis results indicated they were very hydrophilic and electronegative. The biodistribution studies of two ^99mTc-HYNIC-DG complexes in Kunming mice bearing S 180 tumor showed that ^99mTc-(t/T)HYNIC-DG has more favorable characteristics than ^99mTc-(t/E)HYNIC-DG. High tumor uptake, low or negligible accumulation in non-target organs, and good retention, suggesting ^99mTc-(t/T)HYNIC-DG would be a novel potential tumor imaging agent.     

Paper chromatographic and paper elettrophoretic study of the solution chemistry of Tc-99m-methylendiphosphonate and of Tc-99m-dimercaptosuccinate for improving the tumour-affinity of Tc-99m during scintigraphic imaging of cancer

In order to find the conditions under which Tc-99m-methylenediphosphonate (Tc-99m-MDP) and Tc-99m(V)-dimercaptosuccinate (Tc-99m(V)-DMSA) may become tumour-seeking agents, leaving healthy organs free from the radionuclide uptake, the solution chemistry of these radiopharmaceuticals was studied by paper chromatography and paper electrophoresis in distilled water, in physiological saline, in NAHCO3, and ascorbic acid solutions. Both radiopharmaceuticals are anionic in the radiopharmaceutical solution but get easily hydrolysed to form cationic Tc-99m species which concentrates in healthy bone and in some bone metastases. Tc-99m (V)-DMSA being more stable remains long in the blood pool giving undesirable presence of the radionuclide in lung, heart and kidneys, in addition to its reduced uptake in bone metastases and in some primaries. We are trying to eliminate these drawbacks of healthy organ uptake of Tc-99-m(V)-DMSA not only to get a clean scintigraphic image of the tumour with this radiopharmaceutical but to extend its formulation, thus obtained, to prepare radiopharmaceutical with Re-188, which is the higher homologue of Tc-99m, for systemic therapy of cancer. Essentially similar solution chemistry of both radiopharmaceuticals suggests that like Tc-99m-MDP, technetium-99m-dimercaptosuccinate is also a complex of tetravalent Tc-99m and not of pentavalent Tc-99m as so far supposed to be.     

Investigation of 99mTc labeled tumor seeking agents--usefulness of 99mTc-isoniazid

For the development of 99mTc labeled tumor seeking agents, 273 drugs and chemicals were evaluated. Agents labeled by SnCl2-HCl method were injected to rats bearing Yoshida sarcoma. Scintigrams of the rats 2 hours after injection and the excised tumor and organs placed on a plate were taken and evaluated their affinity to the tumor. Isoniazid (INH) was found to be the most useful agent as a result of this screening study. Intensive study on 99mTc-INH was subsequently performed. Another labeling method, FeSO4-H2SO4 method, was evaluated and shown to be superior in both absolute tumor uptake and tumor to muscle ratio. Uptake of 99mTc-INH to Yoshida sarcoma occurred early after injection and maintained its level until later time. On the other hand, radioactivity in the blood and muscle decreased rapidly; that is, tumor to blood and muscle ratio showed rapid increase. Other animal tumor models, mouse bearing Ehrlich tumor or Sarcoma 180, were also used to evaluate the usefulness of 99mTc-INH. The labeled agent showed good localization in these tumors too. In conclusion 99mTc-INH might be a good tumor seeking agent and further clinical trials would be warrant.     

A novel peptide-based probe 99mTc-PEG6-RD-PDP2 for the molecular imaging of tumor PD-L2 expression

Tumor-related PD-L2 expression is associated with the clinical efficacy of PD-1/PD-L1 blockade therapy. PD-L2-specific imaging can help selecting patients for appropriate immunotherapy. In this study, a PD-L2-targeting peptide (PDP2) was screened by the one-bead one-compound combinatorial library approach. Using the retro-inverso d-peptide of PDP2 (RD-PDP2) and PEGylation strategies, we developed a novel Tc-99m-labeled PD-L2-targeting peptide as a SPECT tracer (^99mTc-PEG₆-RD-PDP2) for imaging of tumor PD-L2 expression. The radiolabeling yield of ^99mTc-PEG₆-RD-PDP2 was greater than 95% by the standard HYNIC/tricine/TPPTS labeling procedure. ^99mTc-PEG₆-RD-PDP2 displayed high PD-L2-binding specificity both in vitro and in vivo. SPECT/CT imaging with ^99mTc-PEG₆-RD-PDP2 showed that the A549-PD-L2 tumors were clearly visualized, whereas the signals in PD-L2-negative A549 tumors were much lower. In vivo blocking study suggested that the tumor uptake of ^99mTc-PEG₆-RD-PDP2 was PD-L2 specifically mediated. ^99mTc-PEG₆-RD-PDP2 is a promising SPECT probe for the non-invasive imaging of tumor PD-L2 expression and has a great potential in guiding the anti-PD-1 or anti-PD-L1 immunotherapy of cancer.     

Liposomes prepared from synthetic amphiphiles. II. Their interaction with Ehrlich ascites tumor cells and tissue distribution in Ehrlich solid tumor-bearing mice

The interaction of 99mTc-labeled liposomes prepared from synthetic amphiphiles containing amino acid residues with Ehrlich ascites tumor cells in vitro and their tissue distributions in Ehrlich solid tumor-bearing mice were investigated. The amphiphiles used were N,N-didodecyl-N alpha-[6-(trimethylammonio)hexanoyl]-L-alaninamide bromide N+C5Ala2C12), N,N-didodecyl-N alpha-(6-[dimethyl(2-carboxyethyl)ammonio]hexanoyl)-L- alaninamide bromide (CAC2N+C5Ala2C12) and S-[1-carboxy-2- ([2,3-bis(hexadecyloxy)propoxy]carbonyl)ethyl]homocysteine (HcyM-G2C1 6). Most of the radioactivity of N+C5Ala2C12 and CAC2N+C5Ala2C12 liposomes was firmly bound to Ehrlich ascites tumor cells in vitro. On the other hand, the accumulation of three 99mTc-labeled liposomes in the tumor of Ehrlich solid tumor-bearing mice was low (about 1% dose per gram of tissue), and most of the liposomes were taken up highly in the liver and spleen of the tumor-bearing mice. However, the radioactivity of the liposomes in the tumor, especially that of N+C5Ala2C12 and CAC2N+C5Ala2C12 liposomes, decreased more slowly with time than in the liver in up to 24 h after injection, suggesting that these liposomes were hard to separate from the tumor cells.     

Preparation and biological evaluation of the new chlorin photosensitizer T3,4BCPC for detection and treatment of tumors

The new water-soluble photosensitizer 5,10,15,20-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl]chlorin (T3,4BCPC) has been prepared, characterized and labeled with 99mTc radionuclide. The radiotracer was evaluated for tissue distribution in Wistar rats. Accumulation of administrated activities in the liver, kidney, bladder and large intestine at 4 h post-injection indicated that the labeled ligand was largely eliminated through the renal and partly through the hepatobiliary system. In vivo biodistribution studies of the labeled compound were carried out in rodent and murine tumor models in comparison with other tumor-seeking radiopharmaceuticals such as 99mTc(V)-dimercaptosuccinic acid (DMSA), 201thallous chloride (TlCl) and 99mTc-citrate using a gamma camera computer system. In N-nitrosomethylurea (NMU)-induced rat mammary tumors, the labeled ligand showed a five-fold tumor to muscle (T/M) ratio compared to 99mTc(V)-DMSA (3-fold) and 201TlCl (3-fold). In the case of C(3)H/J virus-induced spontaneous mammary tumors, the differences were not marked. However, in the transplanted rat C(6)-glioma, the T/M ratio of the labeled compound was appreciably higher (four-fold) than that noted with 99mTc(V)-DMSA (two-fold), 201TlCl (three-fold) and 99mTc-citrate (more than three-fold). These findings suggest that the radiolabeled T3,4BCPC may have potential for the detection of cancer. In order to ascertain the efficacy of the compound for photodynamic therapy applications, a preclinical PDT study was carried out in fibrosarcoma-bearing mice after injecting 5.0 mg/kg body weight of the T3,4BCPC. A laser dose of 20 mW for 60 s resulted in 80% destruction of tumors. These data suggest that this molecule could be useful for PDT of cancer. The labeled agent could also be useful in monitoring the progression/regression of tumors before, during, and after chemotherapy, radiation therapy or PDT.     

Technetium-99m complexes with steroid-2-aminooxyethyliminodiacetic acid conjugates

Conjugates of 2-aminooxyethyliminodiacetic acid with estrone, testosterone, epiandrosterone, 17-alpha-hydroxy-progesterone and progesterone were synthesized and their complexes with Tc-99m were successfully prepared in good yields, which indicated the agent to be promising for metal-labeling of biomolecules and related substances containing one or more carbonyl groups. The biodistribution and scintigraphic studies in mice bearing Ehrlich tumor and mammary tumor showed that the radioactivity accumulated considerably in the tumor tissues, but the tumor images were somewhat obscured.     

Affinity of the elements in group VI of the periodic table to tumors and organs]

In order to investigate the tumor affinity radioisotopes, chromium (51Cr), molybdenum (99Mo), tungsten (181W), selenium (75Se) and tellurium (127mTe)--the elements of group VI in the periodic table--were examined, using the rats which were subcutaneously transplanted with Yoshida sarcoma. Seven preprarations, sodium chromate (Na251CrO4), chromium chloride (51CrCl3), normal ammonium molybdate ((NH4)299MoO7), sodium tungstate (Na2181WO4), sodium selenate (Na275SeO4), sodium selenite (Na275SeO3) and tellurous acid (H2127mTeO3) were injected intravenously to each group of tumor bearing rats. These rats were sacrificed at various periods after injection of each preparation: 3 hours, 24 hours and 48 hours in all preparations. The radioactivities of the tumor, blood, muscle, liver, kidney and spleen were measured by a well-type scintillation counter, and retention values (in every tissue including the tumor) were calculated in percent of administered dose per g-tissue weight. All of seven preparations did not have any affinity for malignant tumor. Na251CrO4 and H2127mTeO3 had some affinity for the kidneys, and Na275SeO3 had some affinity for the liver. Na2181WO4 and (NH4)299MoO4 disappeared very rapidly from the blood and soft tissue, and about seventy-five percent of radioactivity was excreted in urine within first 3 hours.     

Preparation and the biodistribution study of [131I]-5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin and 5-(4-aminophenyl)-10,15,20-triphenylporphyrin

[¹³¹I]-5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin and [¹³¹I]-5-(4-aminophenyl)-10,15,20-triphenylporphyrin (¹³¹I-TPPOH and ¹³¹I-TPPNH₂) were prepared and their biodistribution properties were evaluated in normal Kunming (KM) mice and SMMC-7721 tumor-bearing BALB/c mice. The optimized labeling yields were 98 and 96 % for ¹³¹I-TPPOH and ¹³¹I-TPPNH₂, respectively. They were stable in vitro saline and in vivo. Both compounds had a specific affinity to liver and lung, and mainly metabolized through liver. They showed a time-dependent accumulation and retainable characteristics in SMMC-7721 tumor. These results supported their potential value for targeted tumor therapy agents.     

ENHANCEMENT OF ULTRAVIOLET-DNA REPAIR IN den V GENE TRANSFECTANTS and T4 ENDONUCLEASE V-LIPOSOME RECIPIENTS

The phage T4 denV gene, coding for the pyrimidine-dimer specific T4 endonuclease V, was transfected into human repair-proficient fibroblasts, repair-deficient xeroderma pigmentosum fibroblasts, and into wild type CHO hamster cells. Transfectants maintained denV DNA and expressed denV mRNA. Purified T4 endonuclease V encapsulated in liposomes was also used to treat repair-proficient and -deficient human cells. The denV transfected clones and liposome-treated cells showed increased unscheduled DNA synthesis and enhanced removal of pyrimidine dimers compared to controls. Both denV gene transfection and endonuclease V liposome treatment enhanced post-UV survival in xeroderma pigmentosum cells but had no effect on survival in repair-proficient human or hamster cells. The results demonstrate that an exogenous DNA repair enzyme can correct the DNA repair defect in xeroderma pigmentosum cells and enhance DNA repair in normal cells.     

Synthesis and Biological Evaluation of 1-(2-(6-Methoxynaphthalen-2-yl)-6-methylnicotinoyl)-4-Substituted Semicarbazides/Thiosemicarbazides as Anti-Tumor Nur77 Modulators

Nur77 is an orphan nuclear receptor that participates in the occurrence and development of a variety of tumors. Many agonists of Nur77 have been reported to have significant anticancer effects. Our previous studies have found that the introduction of bicyclic aromatic rings, such as naphthalyl and quinoline groups, into the N′-methylene position of indoles’ Nur77 modulators can effectively improve the anti-tumor activity of the target compounds. Following our previous studies, a series of novel 1-(2-(6-methoxynaphthalen-2-yl)-6-methylnicotinoyl)-4-substituted semicarbazide/thiosemicarbazide derivatives 9a–9w were designed and synthesized in four steps from 6-methoxy-2-acetonaphthone and N-dimethylformamide dimethylacetal. All compounds were characterized by ¹H-NMR, ¹³C-NMR and HRMS, and their anti-tumor activity on various cancer cell lines such as A549, HepG2, HGC-27, MCF-7 and HeLa are also evaluated. From the series of compounds, 9h exhibited the most potent anti-proliferative activity against several cancer cells. Colony formation and cell cycle experiments showed that compound 9h inhibited cell growth and arrested the cell cycle. Additionally, 9h leads to the cleavage of PARP. We initially explored the mechanism of 9h-induced apoptosis and found that compound 9h can upregulate Nur77 expression and triggered Nur77 nuclear export, indicating the occurrence of Nur77-mediated apoptosis. These results suggested that 9h may be a promising anti-tumor leading compound for the further research.