Evaluation of a peptidomimetic targeting the receptor NRP-1 for treatment of medulloblastoma

Abstract : Medulloblastoma (MB) is the most common malignant pediatric brain tumors which is the leading cause of cancer death in children. Despite the progress of new treatments, the risk of recurrence, morbidity, and death after treatment remain important. The neuropilin-1 receptor (NRP-1) has recently been implicated in tumor progression of MBs, which seems to play an important role in the phenotype of cancer stem cells (CSCs). Targeting this molecule could thus present an interesting therapeutic value in the treatment of MB. We have selected cancer stem like cells of MBs in the form of medullospheres (MSs) from 3 cell lines (DAOY, D283-Med and Med-D341). These models were characterized by expression of neuropilins (NRP-1 and NRP-2) and phenotypic markers (CD133, CD15 and NF-M). Results showed a significant increase of the expression of NRP-1 by our CSCs models cultured in MSs that confirms our targeting strategy. The impact of the treatment of these cells with an innovative compound specifically targeting NRP-1, MR438, was then evaluated in vitro alone and in association with radiotherapy, especially on the study of the capacity for self-renewal. A decrease of self-renewal capacity for MB stem cells after exposition of MR438 with an increase of radiosensitivity for the 3 cell models in vitro was demonstrated. In vivo, MR438 was evaluated on heterotopic xenograft models in nude mice and showed a significant augmentation of radiosensitivity for DAOY tumors with a tendency to decrease tumor progression for the other 2 cell lines. Interestingly, the compound MR438 induced a significant decrease in the number of stem cells for all of our models. The compound appeared to induce CSCs to a differentiated phenotype at least for the DAOY cells, although mechanisms could not be clearly elucidated. In conclusion, inhibition of NRP-1 via MR438 seems to stimulate the differentiation of CSCs that may eventually reduce the progression of MB and bring a benefit in association with radiotherapy. Evaluation of this compound on orthotopic models of MB would provide information on its effectiveness on models closer to the physiopathology taking into account its distribution at the cerebral level
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Theses
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http://docnum.univ-lorraine.fr/ulprive/DDOC_T_2018_0115_GONG.pdf
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https://hal.univ-lorraine.fr/tel-01902449
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Submitted on : Tuesday, October 23, 2018 - 3:26:18 PM
Last modification on : Wednesday, October 24, 2018 - 1:19:29 AM

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  • HAL Id : tel-01902449, version 1

Citation

Caifeng Gong. Evaluation of a peptidomimetic targeting the receptor NRP-1 for treatment of medulloblastoma. Human health and pathology. Université de Lorraine, 2018. English. ⟨NNT : 2018LORR0115⟩. ⟨tel-01902449⟩

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