TP53 mutated glioblastoma stem-like cell cultures are sensitive to dual mTORC1/2 inhibition while resistance in TP53 wild type cultures can be overcome by combined inhibition of mTORC1/2 and Bcl-2

SYSTEMIC INFLAMMATORY INDICES IN PATIENTS WITH MALIGNANT GLIOMAS AND EFFECTS OF PLATELET SECRETOME IN VITRO

BACKGROUND

To date, no significant clinical progress has been achieved in the treatment of brain malignant gliomas (MG), and the active search for non-invasive circulating biomarkers continues. The prognostic significance of the ratio of the main peripheral blood cell populations of patients with MG is evaluated. Considerable attention is paid to the secretome of platelets (Pt) of peripheral blood.

AIM

To evaluate the indicators of the peripheral blood cell population ratios in patients with brain MG and to study the influence of the secretome of Pt (SPt) of the peripheral blood of patients with brain MG in cell cultures in vitro.

MATERIALS AND METHODS

We studied samples of peripheral blood from patients with glioma CNS WHO grade G2 (n = 5), G3 (n = 12), and G4 (n = 20). The peripheral blood cell counts were analyzed in the preoperative period on an automatic hematology analyzer. The in vitro study of SPt was performed on the U251 human glioblastoma cell line cultured with SPt from MG patients or SPt pre-incubated with anti-TGF-β1 antibody. Cell cultures were observed for 72 h, and mitotic index (MI) was calculated.

RESULTS

In MG patients, the count of peripheral blood leukocytes and neutrophils increased (p < 0.05). The neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII) increased by 2-3 times compared to control. Nevertheless, correlation analysis did not reveal significant relationships between quantitative indicators of peripheral blood cells and the tumor malignancy degree in MG patients. The MI in U251 cells increased under the influence of SPt from patients with MG (p < 0.021), correlated with the tumor degree of malignancy (r = 0.246, p = 0.014). Pre-incubation of SPt with anti-TGF-β1 antibody tends to neutralize this promitotic effect.

CONCLUSION

In MG patients, the integral indicators of NLR and SII increased but no significant relationship with the degree of tumor malignancy was found. In U251 cells, promitotic effects of SPt of MG patients partially decreased by anti-TGF-β1 antibody.

Antitumor Potential of Antiepileptic Drugs in Human Glioblastoma: Pharmacological Targets and Clinical Benefits

Glioblastoma (GBM) is characterized by fast-growing cells, genetic and phenotypic heterogeneity, and radio-chemo-therapy resistance, contributing to its dismal prognosis. Various medical comorbidities are associated with the natural history of GBM. The most disabling and greatly affecting patients' quality of life are neurodegeneration, cognitive impairment, and GBM-related epilepsy (GRE). Hallmarks of GBM include molecular intrinsic mediators and pathways, but emerging evidence supports the key role of non-malignant cells within the tumor microenvironment in GBM aggressive behavior. In this context, hyper-excitability of neurons, mediated by glutamatergic and GABAergic imbalance, contributing to GBM growth strengthens the cancer-nervous system crosstalk. Pathogenic mechanisms, clinical features, and pharmacological management of GRE with antiepileptic drugs (AEDs) and their interactions are poorly explored, yet it is a potentially promising field of research in cancer neuroscience. The present review summarizes emerging cooperative mechanisms in oncogenesis and epileptogenesis, focusing on the neuron-to-glioma interface. The main effects and efficacy of selected AEDs used in the management of GRE are discussed in this paper, as well as their potential beneficial activity as antitumor treatment. Overall, although still many unclear processes overlapping in GBM growth and seizure onset need to be elucidated, this review focuses on the intriguing targeting of GBM-neuron mutual interactions to improve the outcome of the so challenging to treat GBM.

Genomic and Epigenomic Features of Glioblastoma Multiforme and its Biomarkers

Glioblastoma multiforme is a serious and life-threatening tumor of central nervous system, characterized by aggressive behavior, poor prognosis, and low survival rate. Despite of the availability of aggressive antitumor therapeutic regimen for glioblastoma (radiotherapy followed by chemotherapeutic dose), recovery rate, and patients' survival ratio is attributed to the lack of selectivity of therapeutic drugs and less advancement in cancer therapeutics over last decade. Moreover, tools employed in conventional diagnosis of glioblastoma are more invasive and painful, making the process excruciating for the patients. These challenges urge for the need of novel biomarkers for diagnosis, prognosis, and prediction purpose with less invasiveness and more patient compliance. This article will explore the genetic biomarkers isocitrate dehydrogenase mutation, MGMT mutations, and EGFR that can be deployed as an analytical tool in diagnosis of disease and prognosis of a therapeutic course. The review also highlights the importance of employing novel microRNAs as prognostic biomarkers. Recent clinical advancements to treat GBM and to prevent relapse of the disease are also discussed in this article in the hope of finding a robust and effective method to treat GBM.

mTOR as a senescence manipulation target: A forked road

Cellular senescence, cancer and aging are highly interconnected. Among many important molecular machines that lie at the intersection of this triad, the mechanistic (formerly mammalian) target of rapamycin (mTOR) is a central regulator of cell metabolism, proliferation, and survival. The mTOR signaling cascade is essential to maintain cellular homeostasis in normal biological processes or in response to stress, and its dysregulation is implicated in the progression of many disorders, including age-associated diseases. Accordingly, the pharmacological implications of mTOR inhibition using rapamycin or others rapalogs span the treatment of various human diseases from immune disorders to cancer. Importantly, rapamycin is one of the only known pan-species drugs that can extend lifespan. The molecular and cellular mechanisms explaining the phenotypic consequences of mTOR are vast and heavily studied. In this review, we will focus on the potential role of mTOR in the context of cellular senescence, a tumor suppressor mechanism and a pillar of aging. We will explore the link between senescence, autophagy and mTOR and discuss the opportunities to exploit senescence-associated mTOR functions to manipulate senescence phenotypes in age-associated diseases and cancer treatment.

mTOR-targeted cancer therapy: great target but disappointing clinical outcomes, why?

The mammalian target of rapamycin (mTOR) critically regulates several essential biological functions, such as cell growth, metabolism, survival, and immune response by forming two important complexes, namely, mTOR complex 1 (mTORC1) and complex 2 (mTORC2). mTOR signaling is often dysregulated in cancers and has been considered an attractive cancer therapeutic target. Great efforts have been made to develop efficacious mTOR inhibitors, particularly mTOR kinase inhibitors, which suppress mTORC1 and mTORC2; however, major success has not been achieved. With the strong scientific rationale, the intriguing question is why cancers are insensitive or not responsive to mTOR-targeted cancer therapy in clinics. Beyond early findings on induced activation of PI3K/Akt, MEK/ERK, and Mnk/eIF4E survival signaling pathways that compromise the efficacy of rapalog-based cancer therapy, recent findings on the essential role of GSK3 in mediating cancer cell response to mTOR inhibitors and mTORC1 inhibition-induced upregulation of PD-L1 in cancer cells may provide some explanations. These new findings may also offer us the opportunity to rationally utilize mTOR inhibitors in cancer therapy. Further elucidation of the biology of complicated mTOR networks may bring us the hope to develop effective therapeutic strategies with mTOR inhibitors against cancer.

Familial/inherited cancer syndrome: a focus on the highly consanguineous Arab population

The study of hereditary cancer, which accounts for ~10% of cancer cases worldwide is an important subfield of oncology. Our understanding of hereditary cancers has greatly advanced with recent advances in sequencing technology, but as with any genetic trait, gene frequencies of cancer-associated mutations vary across populations, and most studies that have located hereditary cancer genes have been conducted on European or Asian populations. There is an urgent need to trace hereditary cancer genes across the Arab world. Hereditary disease is particularly prevalent among members of consanguineous populations, and consanguineous marriages are particularly common in the Arab world. There are also cultural and educational idiosyncrasies that differentiate Arab populations from other more thoroughly studied groups with respect to cancer awareness and treatment. Therefore, a review of the literature on hereditary cancers in this understudied population was undertaken. We report that BRCA mutations are not as prevalent among Arab breast cancer patients as they are among other ethnic groups, and therefore, other genes may play a more important role. A wide variety of germline inherited mutations that are associated with cancer are discussed, with particular attention to breast, ovarian, colorectal, prostate, and brain cancers. Finally, we describe the state of the profession of familial cancer genetic counselling in the Arab world, and the clinics and societies dedicated to its advances. We describe the complexities of genetic counselling that are specific to the Arab world. Understanding hereditary cancer is heavily dependent on understanding population-specific variations in cancer-associated gene frequencies.

Targeting mTOR for cancer therapy

Mechanistic target of rapamycin (mTOR) is a protein kinase regulating cell growth, survival, metabolism, and immunity. mTOR is usually assembled into several complexes such as mTOR complex 1/2 (mTORC1/2). In cooperation with raptor, rictor, LST8, and mSin1, key components in mTORC1 or mTORC2, mTOR catalyzes the phosphorylation of multiple targets such as ribosomal protein S6 kinase β-1 (S6K1), eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), Akt, protein kinase C (PKC), and type-I insulin-like growth factor receptor (IGF-IR), thereby regulating protein synthesis, nutrients metabolism, growth factor signaling, cell growth, and migration. Activation of mTOR promotes tumor growth and metastasis. Many mTOR inhibitors have been developed to treat cancer. While some of the mTOR inhibitors have been approved to treat human cancer, more mTOR inhibitors are being evaluated in clinical trials. Here, we update recent advances in exploring mTOR signaling and the development of mTOR inhibitors for cancer therapy. In addition, we discuss the mechanisms underlying the resistance to mTOR inhibitors in cancer cells.

Biomarkers and therapeutic advances in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a malignant tumor within the brain. Generally classified as primary and secondary with several different subtypes, ample molecular biomarkers have risen throughout the years which have garnered the attention of researchers. The advancements in genomics and proteomics have allowed researchers to gather prominent molecular biomarkers. All these biomarkers are gathered by means of biopsy or bodily fluid sample collection and are quantitatively analyzed by polymerase chain reaction coupled with other computational technologies. This review highlights the significance, regulation and prevalence of molecular biomarkers such as O⁶ -methylguanine-DNA methyltransferase, epidermal growth factor receptor vIII, isocitrate dehydrogenase mutation and several others which expressed differently in different types and molecular subtypes of GBM. The discoveries and roles of GBM-specific microRNAs including miR-21 and miR-10b as biomarkers with promising prognostic values were also delineated. The role and mechanism of biomarkers in GBM tumorigenesis are essential in the development of therapy for patients suffering from the disease itself. Thus, this review also discusses the mechanisms, effects and limitations of therapy such as temozolomide, viral gene transfer, biomarker-based vaccines or even engineered T cells for more specific responses. Biomarkers have displayed a high value and could eventually be utilized as drug targets. It is hoped that by combining different aspects of the disease which present with different biomarkers could lead to the development of a robust, effective and innovative take on GBM therapy.