The Combined Treatment with Chemotherapeutic Agents and the Dualsteric Muscarinic Agonist Iper-8-Naphthalimide Affects Drug Resistance in Glioblastoma Stem Cells.

Claudia Guerriero,Clelia Dallanoce,Luciano Conti,Carlo Matera,Marco De Amici,Ada Maria Tata,Donatella Del Bufalo

doi:10.3390/cells10081877

Claudia Guerriero, Clelia Dallanoce + Show 5 more

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https://doi.org/10.3390/cells10081877

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Abstract

Background: Glioblastoma multiforme (GBM) is characterized by heterogeneous cell populations. Among these, the Glioblastoma Stem Cells (GSCs) fraction shares some similarities with Neural Stem Cells. GSCs exhibit enhanced resistance to conventional chemotherapy drugs. Our previous studies demonstrated that the activation of M2 muscarinic acetylcholine receptors (mAChRs) negatively modulates GSCs proliferation and survival. The aim of the present study was to analyze the ability of the M2 dualsteric agonist Iper-8-naphthalimide (N-8-Iper) to counteract GSCs drug resistance. Methods: Chemosensitivity to M2 dualsteric agonist N-8-Iper and chemotherapy drugs such as temozolomide, doxorubicin, or cisplatin was evaluated in vitro by MTT assay in two different GSC lines. Drug efflux pumps expression was evaluated by RT-PCR and qRT-PCR. Results: By using sub-toxic concentrations of N-8-Iper combined with the individual chemotherapeutic agents, we found that only low doses of the M2 agonist combined with doxorubicin or cisplatin or temozolomide were significantly able to counteract cell growth in both GSC lines. Moreover, we evaluated as the exposure to high and low doses of N-8-Iper downregulated the ATP-binding cassette (ABC) drug efflux pumps expression levels. Conclusions: Our results revealed the ability of the investigated M2 agonist to counteract drug resistance in two GSC lines, at least partially by downregulating the ABC drug efflux pumps expression. The combined effects of low doses of conventional chemotherapy and M2 agonists may thus represent a novel promising pharmacological approach to impair the GSC-drug resistance in the GBM therapy.

Highlights

IntroductionGlioblastoma multiforme (GBM) is characterized by cellular and morphological heterogeneity, due to the coexistence of different cell populations with various grades of differentiation and distinct genetic and epigenetic profiles [5,6]
We initially evaluated the chemosensitivity of two Glioblastoma Stem Cells (GSCs) lines, analyzing the cell growth by the MTT assay at different concentrations of temozolomide, cisplatin, and doxorubicin after 72, 96, and 120 h of treatment (Figure 3)
The results of this study confirm that the M2 agonist N-8-Iper counteracts cell growth in different GSCs

Summary

Introduction

GBM is characterized by cellular and morphological heterogeneity, due to the coexistence of different cell populations with various grades of differentiation and distinct genetic and epigenetic profiles [5,6]. This tumor heterogeneity plays a crucial role in tumor growth, progression, invasiveness, and resistance to therapy [7]. The theory that cancer stem cells are involved in the initiation and evolution of the tumors has emerged These cells, through asymmetric divisions, on one side maintain their stemness characteristics by preserving their subpopulation and, on the other, generate more differentiated daughter cells that will constitute the majority of the tumor bulk [7]. Methods: Chemosensitivity to M2 dualsteric agonist N-8-Iper and chemotherapy drugs such as temozolomide, doxorubicin, or cisplatin was evaluated in vitro by MTT assay in two different

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