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

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.

The activation of M2 muscarinic receptor inhibits cell growth and survival in human epithelial ovarian carcinoma

“…In conclusion, our results, according to the results obtained in other tumor types, 9,12,14,15,44 confirm the inhibitory role of M2 receptors on tumor cell proliferation and survival.…”

“…The data showing the prevalence of M3 receptors in ovarian cancer 19 and the lower levels of M2 receptors, as demonstrated in the present work, further support the significant correlation between mAChR status and poor prognosis in patients with ovarian cancer. 18 In conclusion, our results, according to the results obtained in other tumor types, 9,12,14,15,44 confirm the inhibitory role of M2 receptors on tumor cell proliferation and survival.…”

“…The identification of novel compounds able to overcome drug resistance that can be used as adjuvant along with chemotherapeutic drugs are needed to improve the survival of ovarian cancer patients. Moreover, the development of novel M2 subtypes specific agonists with higher affinity compared to APE that could be used at lower concentrations than APE may also represent new interesting therapeutic perspectives for the ovarian cancer treatment 44,45 …”

Effects Mediated by Dimethyl Fumarate on In Vitro Oligodendrocytes: Implications in Multiple Sclerosis

“…The MTT assay is commonly used to evaluate cell growth [ 40 , 41 , 42 ]; for this purpose, it was used to examine the possible effects of DMF on Oli neu cell growth. We evaluated the effect of 25 μM DMF on Oli neu cells after 1-2-3-4 DIV of treatment.…”

Neurotransmitters: Potential Targets in Glioblastoma

“…For instance, the combination of N-8-Iper and doxorubicin, cisplatin or temozolomide shows a stronger impairment of the growth of GSC lines than that with the single treatment. This may be related to the decrease in the ATP-binding cassette (ABC) efflux pumps mediated by the M2 receptor, reducing the excretion of chemotherapeutic drugs [ 136 ].…”