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Molecular study of synthesis of protoporphyrin IX in fluoropositive and fluoronegative cell cultures of human glioblastoma

Pavlova G.,Institute of Gene Biology, RAS, Ltd Apta-pharm, Russia; Pustogarov N., Institute of Gene Biology, RAS, Moscow, Russia; Kopylov A., Ltd Apta-pharm, MGU, Moscow, Russia; Panteleev D, Institute of Gene Biology, RAS, Moscow, Russia
2. Ltd Apta-pharm, Russia
3. MGU, Moscow, Russia

2. Ltd Apta-pharm, Russia
3. MGU, Moscow, Russia


Glioblastoma is a tumor from a heterogeneous group having neuroectodermal origin. Surgery is still the main approach to treat gliomas. To increase efficiency of the surgery a photodynamic diagnostics is applied, based on the fluorescence of protoporphyrin IX. 5-aminolevulinic acid (5-ALA) is a precursor mitochondrial heme. After systemic administration of 5-aminolevulinic acid (5-ALA), it is methabolized into protoporphyrin IX, which, in turn, accumulates in the tumors cells. Due to the protoporphyrin IX fluorecence, it is possible to localize and remove the tumore more presicely. It was shown that the fluorescence intensity of protoporphyrin IX correlates well with the proliferation rate of the tumor cells. Though 30% of the tumors, especially metastatic ones, do not exibit fluorescence properties. Today a molecular mechanisms of the pathways from 5-ALA administration till protoporphyrin IX fluorescence are not known in details A set of enzymes involved into protoporphyrin IX synthesis is the following: ALAD, HMBS, UROS, UROD, CPOX, PPOX, FECH.
In this research a collection of tissues of glioblastomas with different grades and fluorescence capacity has been estamlished; all tisues have etiology. In this research primary and continuous cell cultures, as well as neurospheres, from tissues of human glioblastoma have been developed. All tisues were characterized with immunohistochemical methods, and fluoropositivity and fluoronegativity. Lucky enough, the fluoropositive glioma yields fluoropositive cell cultures, and fluoronegative tissues yield fluoronegative cell cultures, respectively. Because the above mentioned set of conversion enzymes are known, the expression level of corresponding mRNAs have been examined by real time PCR, and the data for fluoropositive and fluoronegative cells have been compared. The expression level of СРОХ mRNA (coproporphyrinogen oxidase) is up-regulated in the fluoropositive samples. More paractical finding is that the increasing the duration time from 5-ALA till the surgaery from two hours up to 1-2 days increases the number of fluorescent tumors in half.

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