(5-(2-4-bis((3s)-3-methylmorpholin-4-yl)pyrido(2-3-d)pyrimidin-7-yl)-2-methoxyphenyl)methanol and Brain-Neoplasms

Autophagy is a vital process that involves degradation of long-lived proteins and dysfunctional organelles and contributes to cellular metabolism. Glioma-initiating cells (GICs) have the ability to self-renew, differentiate into heterogeneous types of tumor cells, and sustain tumorigenicity; thus, GICs lead to tumor recurrence. Accumulating evidence indicates that autophagy can induce stem cell differentiation and increase the lethality of temozolomide against GICs. However, the mechanism underlying the regulation of GIC self-renewal by autophagy remains uncharacterized. In the present study, autophagy induced by AZD8055 and rapamycin treatment suppressed GIC self-renewal in vitro. We found that autophagy inhibited Notch1 pathway activation. Moreover, autophagy activated Notch1 degradation, which is associated with maintenance of the self-renewal ability of GICs. Furthermore, autophagy abolished the tumorigenicity of CD133 + U87-MG neurosphere cells in an intracranial model. These findings suggest that autophagy regulating GICs self-renewal and tumorigenicity is probably bound up with Notch1 degradation. The results of this study could aid in the design of autophagy-based clinical trials for glioma treatments, which may be of great value.

Topics: Animals; Antineoplastic Agents; Autophagy; Brain Neoplasms; Calcium-Binding Proteins; Carcinogenesis; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Membrane Proteins; Mice; Mice, Nude; Morpholines; Neoplastic Stem Cells; Proteolysis; Receptor, Notch1; Signal Transduction; Sirolimus; Sodium-Potassium-Exchanging ATPase; Spheroids, Cellular; Survival Analysis; Xenograft Model Antitumor Assays

Glioblastoma is the most malignant tumor of the central nervous system and still lacks effective treatment. This study explores mutational biomarkers of 11 drugs targeting either the RTK/Ras/PI3K, the p53 or the Rb pathway using 25 patient-derived glioblastoma stem-like cell cultures (GSCs).. We found that TP53 mutated GSCs were approximately 3.5 fold more sensitive to dual inhibition of mammalian target of rapamycin complex 1 and 2 (mTORC1/2) compared to wild type GSCs. We identified that Bcl-2(Thr56/Ser70) phosphorylation contributed to the resistance of TP53 wild type GSCs against dual mTORC1/2 inhibition. The Bcl-2 inhibitor ABT-263 (navitoclax) increased sensitivity to the mTORC1/2 inhibitor AZD8055 in TP53 wild type GSCs, while sensitivity to AZD8055 in TP53 mutated GSCs remained unchanged.. Our data suggest that Bcl-2 confers resistance to mTORC1/2 inhibitors in TP53 wild type GSCs and that combined inhibition of both mTORC1/2 and Bcl-2 is worthwhile to explore further in TP53 wild type glioblastomas, whereas in TP53 mutated glioblastomas dual mTORC1/2 inhibitors should be explored.

Topics: Aniline Compounds; Biomarkers, Tumor; Brain Neoplasms; Cell Line, Tumor; Cell Survival; Cohort Studies; DNA Mutational Analysis; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Glioblastoma; High-Throughput Nucleotide Sequencing; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Morpholines; Mutation; Neoplastic Stem Cells; Phosphatidylinositol 3-Kinases; Phosphorylation; Proteome; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53

The mTOR kinase inhibitor AZD8055 inhibits both mTORC1 and mTORC2 leading to disruption of glucose metabolism and proliferation pathways. This study assessed the impact of single and multiple doses of AZD8055 on the uptake of the glucose metabolism marker 2-deoxy-2-[(18) F]fluoro-D-glucose ([(18) F]FDG) and the proliferation marker 3'-deoxy-3'-[(18) F]fluorothymidine ([(18) F]FLT) in U87-MG glioma xenografts.. Mice bearing U87-MG tumours received either vehicle or AZD8055 (20 mg/kg) once daily p.o. Mice were imaged with either [(18) F]FDG or [(18) F]FLT PET to assess treatment response. Comparisons were made between in vivo imaging and ex vivo histopathology data.. Tumour uptake of [(18) F]FDG was reduced by 33 % 1 h after a single dose of AZD8055 and by 49 % following 4 days of dosing. These changes coincided with suppression of the mTOR pathway biomarkers pS6 and pAKT. In contrast, the effect of AZD8055 on [(18) F]FLT uptake was inconsistent.. The very rapid change in [(18) F]FDG uptake following acute AZD8055 treatment suggests that this could be used as an early mechanistic biomarker of metabolic changes resulting from mTOR inhibition. The utility of [(18) F]FLT for measuring the anti-proliferative effect of AZD8055 remains unclear.

Topics: Animals; Biomarkers, Tumor; Brain Neoplasms; Female; Fluorodeoxyglucose F18; Glioma; Humans; Mice; Mice, Nude; Morpholines; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor Receptor-1