Assessment of temozolomide action encapsulated in chitosan and polymer nanostructures on glioblastoma cell lines

Purpose: Glioblastoma multiforme (GBM) remains one of the most devastating diseases known to mankind and affects more than 17,000 patients in the United States alone every year. This malignancy infiltrates the brain early in its course and makes complete neurosurgical resection almost impossible. Recent years have brought significant advances in tumor biology. Many cancers, including gliomas, appear to be supported by cells with stem-like properties. Nanoparticles are excellent candidates to serve as delivery vectors of drugs or biologically active molecules because of their unique chemical and physical properties that result in specific transportation and deposition of such agents in specific organs and tissues.In the current study we have investigated the in vitro action of nanostructural systems (temozolomide encapsulated in chitosan and polymer nanostructures) on high-grade glioma-derived cancer stem cells (CSCs), with the intention of developing a new therapy to treat specific brain tumors with increased efficacy and minimal toxicity. In vitro cytotoxicity and apoptosis measurements indicated that the drug/vector combination facilitated the ability of the alkylating drug TMZ to alter the resistance of these cancer stem cells, suggesting a new chemotherapy strategy even for patients diagnosed with inoperable or recurrent malignant gliomas.Methods: At the National Institute for R & D of Isotopic and Molecular Technologies form Cluj Napoca were synthesized three types of nanostructures chitosan-TMZ, TMZ-chitosan-PEG (poly-ethylene glycol), TMZ-chitosan-PPG (polypropylene glycol). Three type of cell lines (Glioma-derived stem, HFL and HUVEC) were treated with the 3 types of nanostructures and the survival rate of the cells was compare to standard therapy (TMZ).Results: The results showed a reduction in the rate of survival of the tumor cells. Cell proliferation assays clearly demonstrate the differences between conventional chemotherapy (TMZ) and temozolomide encapsulated in chitosan and polymer nanostructures. Conclusion: Nanostructures like chitosan, PEG, PPG are useful as vectors for drugs transport.Despite combined therapy (surgery, radiotherapy, chemotherapy), currently median patient survival is reduced. The key to improving life expectancy could be an effective therapy targeted, customized for each case. An increasingly important role will be new methods of treatment such as immunotherapy, gene therapy or nanotherapy

Efects of PDT with 5-aminolevulinic acid and chitosan on Walker carcinosarcoma

Porphyrins and new chitosan hydrogels based composites with porphyrins are used as active cytotoxic antitumor agents in photodynamic therapy (PDT). Aim: The present study evaluates the effects of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) and 5-ALA associated with chitosan (CS) using Walker carcinosarcoma in rats as experimental model. Methods: The animals were irradiated with red light (l = 685 nm, D = 50 J/cm2, 15 min) 3 h after i.p. administration of 5-ALA (250 mg/kg b.w.) or a mixture of 5-ALA (250 mg/kg b.w.) and CS (1.5 mg/kg b.w.). The animals were sacrificed at 1, 3, 6, 24 h and 14 days after the treatment. The effects of PDT were investigated by morphological studies, monitoring the 5-ALA induced protoporphyrin IX (Pp IX) level in tumor tissue and serum, MMP 2 and 9 (gelatinases) activity in tumor and malondialdehyde level (MDA), marker of the lipoperoxidation process, in tumor and serum. Results: Zymography revealed an increased activity of MMP 2 in tumors from animals treated with 5-ALA PDT. PDT with 5-ALA induced a higher lipid peroxidation in tumor tissue compared with 5-ALA-CS. CS associated to 5 ALA PDT enhanced the accumulation of PS in tumors inducing earlier necrotic changes. In the same time CS reduced MMP 2 activity. Conclusion: Our results suggest that MMPs activation and oxygen reactive species are involved in PDT effects.Порфирины и новые соединения, основу которых составляют гидрогели хитозана с порфиринами, используются как активные цитотоксические противоопухолевые препараты при фотодинамической терапии (PDT). Цель: оценить действие PDT с 5-аминолевуленовой кислотой (5-ALA) и 5-ALA, ассоциированной с хитозаном (CS), на клетки карциносаркомы Уокера. Методы: крыс облучали красным светом (λ = 685 нм, D = 50 Дж/см2 , 15 мин) 3 ч после внутрибрюшинного введения 5-ALA (250 мг/кг) или смеси 5-ALA (250 мг/кг) и CS (1,5 мг/кг). Подопытных животных забивали через 1 ч, 3 ч, 6 ч, 24 ч и 14 дней после воздействия PDT. Эффект PDT определяли с помощью морфологических исследований, регистрируя уровень протопорфирина IX (Pp IX), вызываемого 5-ALA, в опухолевой ткани и сыворотке крови, активность MMP 2 и 9 (желатиназы) в опухоли и уровень малонового диальдегида (MDA), маркера процесса перекисного окисления липидов, в опухоли и сыворотке крови. Результаты: зимографические исследования показали повышенную активность MMP 2 в опухолях животных, которых подвергали 5-ALA PDT. PDT с 5-ALA вызывала повышенный уровень перекисного окисления липидов в опухолевой ткани по сравнению с 5-ALA-CS. CS с 5 ALA PDT усиливал накопление фотосенсибилизирующего вещества (PS) в опухолях, вызывая более ранние некротические изменения. В то же время CS снижал активность MMP 2. Выводы: полученные результаты позволяют предположить, что для проявления эффектов PDT необходимы активация MMP и образование активных форм кислорода

Characteristics of Formvar Films Used to Prevent Alpha-Detector Contamination

Alpha spectrometry is an extremely useful and sensitive for detection of alpha-emitting nuclides. Contamination of the silicon detectors for low-level alpha spectrometry by recoil nuclides is a serious problem in the measurement of alpha emitters decaying to daughter nuclides with short half-lives. This unwanted contamination leads to decreased measurement sensitivity causing a degradation of the limit of detection. The simplest method to prevent this radioactive contamination of detector is to use a catcher film between the alpha source and the detector. In this work we describe the obtaining of the thin formvar films as stopper foils for recoil nuclei and we investigated the influence of these films on alpha spectrometry parameters, as energy shift (~30 keV) and resolution (~7%). No significant deterioration of the alpha spectrometry parameters was observed when using thin formvar films. Using the ASTAR web databases, which calculate stopping powers for alpha particles, the thickness of formvar films was estimated to be about 5.355 × 10−5 g/cm2. The measurements were performed with an ORTEC SOLOIST alpha spectrometer with PIPS detector