In vivo assessment of tumor targeting potential of 68Ga-labelled randomly methylated beta-cyclodextrin (RAMEB) and 2-hydroxypropyl-β-cyclodextrin (HPβCD) using positron emission tomography

Cyclodextrin derivates (CyDs) can form complexes with cyclooxygenase-2 induced tumor promoting prostaglandin E2 (PGE2). Based on our previous observations, 68Ga-labelled CyDs may represent promising radiopharmaceuticals in the positron emission tomography (PET) diagnostics of PGE2 positive tumors. We aimed at evaluating the tumor-targeting potential of 68Ga-NODAGA conjugated randomly methylated beta-cyclodextrin (68Ga-NODAGA-RAMEB) and 2-hydroxypropyl-β-cyclodextrin (68Ga-NODAGA-HPβCD) using in vivo PET imaging with experimental tumor models. Tumor radiopharmaceutical uptake was assessed applying PET and gamma counter in vivo and ex vivo respectively, following the administration of 18FDG, 68Ga-NODAGA-RAMEB or 68Ga-NODAGA-HPβCD via the lateral tail vein to the subsequent tumor-bearing animals: HT1080, A20, PancTu-1, BxPC3, B16-F10, Ne/De and He/De. All investigated tumors were identifiable with both 68Ga-labelled CyDs; however, in vivo results, in correlation with the ex vivo data, revealed that the PGE2 positive BxPC3, A20, Ne/De and He/De tumors presented the highest accumulation. In case of HT1080, A20, B16-F10 tumors significant differences were encountered between the accumulations of both 68Ga-labelled radiopharmaceuticals of the same tumor. Subcutaneously and the orthotopically transplanted Ne/De tumors differed significantly (p ≤ 0.01) regarding tracer uptake. 68Ga-labelled CyDs may open a novel field in the PET diagnostics of PGE2 positive primary tumors and metastases

In Vivo Preclinical Assessment of β-Amyloid–Affine [11C]C-PIB Accumulation in Aluminium-Induced Alzheimer’s Disease-Resembling Hypercholesterinaemic Rat Model

Aluminum (Al) excess and hypercholesterinaemia are established risks of Alzheimer’s disease (AD). The aim of this study was to establish an AD-resembling hypercholesterinaemic animal model—with the involvement of 8 week and 48 week-old Fischer-344 rats—by Al administration for the safe and rapid verification of β-amyloid-targeted positron emission tomography (PET) radiopharmaceuticals. Measurement of lipid parameters and β-amyloid–affine [11C]C-Pittsburgh Compound B ([11C]C-PIB) PET examinations were performed. Compared with the control, the significantly elevated cholesterol and LDL levels of the rats receiving the cholesterol-rich diet support the development of hypercholesterinaemia (p ≤ 0.01). In the older cohort, a notably increased age-related radiopharmaceutical accumulation was registered compared to in the young (p ≤ 0.05; p ≤ 0.01). A monotherapy-induced slight elevation of mean standardised uptake values (SUVmean) was statistically not significant; however, adult rats administered a combined diet expressed remarkable SUVmean increment compared to the adult control (SUVmean: from 0.78 ± 0.16 to 1.99 ± 0.28). One and two months after restoration to normal diet, the cerebral [11C]C-PIB accumulation of AD-mimicking animals decreased by half and a third, respectively, to the baseline value. The proposed in vivo Al-induced AD-resembling animal system seems to be adequate for the understanding of AD neuropathology and future drug testing and radiopharmaceutical development

Characteristic mTOR activity in Hodgkin-lymphomas offers a potential therapeutic target in high risk disease – a combined tissue microarray, in vitro and in vivo study

BACKGROUND: Targeting signaling pathways is an attractive approach in many malignancies. The PI3K/Akt/mTOR pathway is activated in a number of human neoplasms, accompanied by lower overall and/or disease free survival. mTOR kinase inhibitors have been introduced in the therapy of renal cell carcinoma and mantle cell lymphoma, and several trials are currently underway. However, the pathological characterization of mTOR activity in lymphomas is still incomplete. METHODS: mTOR activity and the elements of mTOR complexes were investigated by immunohistochemistry on tissue microarrays representing different human non-Hodgkin-lymphomas (81 cases) and Hodgkin-lymphomas (87 cases). The expression of phospho-mTOR, phospho-4EBP1, phospho-p70S6K, phospho-S6, Rictor, Raptor and Bcl-2, Bcl-xL, Survivin and NF-kappaB-p50 were evaluated, and mTOR activity was statistically analyzed along with 5-year survival data. The in vitro and in vivo effect of the mTOR inhibitor rapamycin was also examined in human Hodgkin-lymphoma cell lines. RESULTS: The majority (>50%) of mantle cell lymphoma, Burkitt lymphoma, diffuse large B-cell lymphoma, anaplastic large-cell lymphoma and Hodgkin-lymphoma cases showed higher mTOR activity compared to normal lymphoid tissues. Hodgkin-lymphoma was characterized by high mTOR activity in 93% of the cases, and Bcl-xL and NF-kappaB expression correlated with this mTOR activity. High mTOR activity was observed in the case of both favorable and unfavorable clinical response. Low mTOR activity was accompanied by complete remission and at least 5-year disease free survival in Hodgkin-lymphoma patients. However, statistical analysis did not identify correlation beetween mTOR activity and different clinical data of HL patients, such as survival. We also found that Rictor (mTORC2) was not overexpressed in Hodgkin-lymphoma biopsies and cell lines. Rapamycin inhibited proliferation and induced apoptosis in Hodgkin-lymphoma cells both in vitro and in vivo, moreover, it increased the apoptotic effect of chemotherapeutic agents. CONCLUSIONS: Targeting mTOR activity may be a potential therapeutic tool in lymphomas. The presence of mTOR activity probably indicates that the inclusion of mTOR inhibition in the therapy of Hodgkin-lymphomas may be feasible and beneficial, especially when standard protocols are ineffective, and it may also allow dose reduction in order to decrease late treatment toxicity. Most likely, the combination of mTOR inhibitors with other agents will offer the highest efficiency for achieving the best clinical response

Mammalian Target of Rapamycin (mTOR) Activity Dependent Phospho-Protein Expression in Childhood Acute Lymphoblastic Leukemia (ALL)

Modern treatment strategies have improved the prognosis of childhood ALL; however, treatment still fails in 25–30% of patients. Further improvement of treatment may depend on the development of targeted therapies. mTOR kinase, a central mediator of several signaling pathways, has recently attracted remarkable attention as a potential target in pediatric ALL. However, limited data exists about the activity of mTOR. In the present study, the amount of mTOR activity dependent phospho-proteins was characterized by ELISA in human leukemia cell lines and in lymphoblasts from childhood ALL patients (n = 49). Expression was measured before and during chemotherapy and at relapses. Leukemia cell lines exhibited increased mTOR activity, indicated by phospho-S6 ribosomal protein (p-S6) and phosphorylated eukaryotic initiation factor 4E binding protein (p-4EBP1). Elevated p-4EBP1 protein levels were detected in ALL samples at diagnosis; efficacy of chemotherapy was followed by the decrease of mTOR activity dependent protein phosphorylation. Optical density (OD) for p-4EBP1 (ELISA) was significantly higher in patients with poor prognosis at diagnosis, and in the samples of relapsed patients. Our results suggest that measuring mTOR activity related phospho-proteins such as p-4EBP1 by ELISA may help to identify patients with poor prognosis before treatment, and to detect early relapses. Determining mTOR activity in leukemic cells may also be a useful tool for selecting patients who may benefit from future mTOR inhibitor treatments

A késő-Kréta ajkai kőszénformáció borostyánjai és kétszárnyú (insecta: Diptera) faunája

A borostyánok a legjobb ősmaradvány-megőrző közegek közé tartoznak, számtalan élőlénycsoport fosszilis képviselőit csak ezekből a kövekből ismerjük. Fosszilis gyantát már a karbon korból is ismerünk, tömegessé azonban csak jóval később, a kréta folyamán váltak, több tucat lelőhelyet ismerünk szerte a világban. Lassan másfél évszázada, hogy felfedezték hazánk területén az első kréta korú borostyánokat, ám a szakma a létezésén kívül eddig nem sokat tud ott az ajkaitokról. Dolgozatom célja az volt, hogy ennek az egyedülálló fosszilis gyantának a zárványait megvizsgáljam és dokumentáljam, és a benne található rovarzárványok közül a kétszárnyúakat a lehetőségekhez mérten minél pontosabban meghatározzam. Összesen 62 rovart tudtam a Diptera rendbe besorolni (a leletanyagban még pókok, hártyásszárnyúak, bogarak és növényi maradványok találhatóak), melyek 4 különböző családba tar toznak (Ceratopogonidae, Mycetobiidae, Phoridae, Dolichopodidae). A vizsgált rovarok mérete nem haladta meg a 2,5 mm-t, illetve a borostyánszemcsék optikai tulajdonságai néha nagyon rosszak (nagyon sötét szín, sok repedés), így a pusztán mikroszkóppal történő vizsgálat ennél pontosabb határozást sokszor nem tesz lehetővé. Két példány esetében mégis sikerült genus szintig határozni, ezek a törpeszúnyogok (Ceratopogonidae) közé tartozó Leptoconops genus képviselői. Ennek a csoportnak volt már ajkaitból leírt faja, a Leptoconops clava , azonban a most vizsgált példányok nem azonosak vele. A meghatározott csoportok jól illeszkednek a többi kréta időszaki borostyán leletegyüttesből ismert kétszárnyú faunába. A Mycetobiidae család jelenléte azonban kivételesen fontos, mivel a most meghatározott példányok a legidősebb, és egyben az első kréta időszaki leletei a csoportnak. A meghatározott csoportok környezeti igényei megfelelnek az Ajkai Kőszén Formáció képződési környezetének (mocsaras–állóvizes, dús vegetációjú környezet), valamint a Leptoconops genus jelenléte utalhat a közeli tengerparti környezetre . Mivel több példány is kitűnő állapotban van, a jövőbeli kutatási tervek között szerepel, hogy jobb képalkotó módszerek (mikro-CT, szinkrotron) segítségével még árnyaltabb képet kapjunk a hazai kréta rovarfauna egykori összetételéről, akár új fajok leírásával is. Fontos lenne újra megtalálni az Ajkai Kőszén Formáció borostyántartalmú rétegeinek felszíni kibukkanását is, hogy a további kutatásokhoz új leletanyagot nyerhessünk