Cooperative p16 and p21 action protects female astrocytes from transformation

MGMT Methylation and Differential Survival Impact by Sex in Glioblastoma

Introduction: Sex differences in glioblastoma (GBM) have been observed in incidence, genetic and epigenetic alterations, and immune response. These differences have extended to the methylation of the MGMT promoter, which critically impacts temozolomide resistance. However, the association between sex, MGMT methylation, and survival is poorly understood, which this study sought to evaluate. Methods: A retrospective cohort study was conducted and reported following STROBE guidelines, based on adults with newly diagnosed GBM who received their first surgical intervention at Cleveland Clinic (Ohio, USA) between 2012 and 2018. Kaplan-Meier and multivariable Cox proportional hazards models were used to analyze the association between sex and MGMT promoter methylation status on overall survival (OS). MGMT was defined as methylated if the mean of CpG 1-5 ≥ 12. Propensity score matching was performed on a subset of patients to evaluate the effect of individual CpG site methylation. Results: A total of 464 patients had documented MGMT methylation status with a mean age of 63.4 (range 19-93) years. A total of 170 (36.6%) were female, and 133 (28.7%) received gross total resection as a first intervention. A total of 42.5% were MGMT methylated, with females more often having MGMT methylation than males (52.1% vs. 37.4%, p = 0.004). In univariable analysis, OS was significantly longer for MGMT promoter methylated than un-methylated groups for females (2 yr: 36.8% vs. 11.1%; median: 18.7 vs. 9.5 months; p = 0.001) but not for males (2 yr: 24.3% vs. 12.2%; median: 12.4 vs. 11.3 months; p = 0.22, p for MGMT-sex interaction = 0.02). In multivariable analysis, MGMT un-methylated versus methylated promoter females (2.07; 95% CI, 1.45-2.95; p < 0.0001) and males (1.51; 95% CI, 1.14-2.00; p = 0.004) had worse OS. Within the MGMT promoter methylated group, males had significantly worse OS than females (1.42; 95% CI: 1.01-1.99; p = 0.04). Amongst patients with data on MGMT CpG promoter site methylation values (n = 304), the median (IQR) of CpG mean methylation was 3.0% (2.0, 30.5). Females had greater mean CpG methylation than males (11.0 vs. 3.0, p < 0.002) and higher per-site CpG methylation with a significant difference at CPG 1, 2, and 4 (p < 0.008). After propensity score matching, females maintained a significant survival benefit (18.7 vs. 10.0 months, p = 0.004) compared to males (13.0 vs. 13.6 months, p = 0.76), and the pattern of difference was significant (P for CpG-sex interaction = 0.03). Conclusions: In this study, females had higher mean and individual CpG site methylation and received a greater PFS and OS benefit by MGMT methylation that was not seen in males despite equal degrees of CpG methylation.

Sex-specific molecular differences in glioblastoma: assessing the clinical significance of genetic variants

Introduction

Glioblastoma multiforme (GBM) is one of the most aggressive types of brain cancer, and despite rigorous research, patient prognosis remains poor. The characterization of sex-specific differences in incidence and overall survival (OS) of these patients has led to an investigation of the molecular mechanisms that may underlie this dimorphism.

Methods

We reviewed the published literature describing the gender specific differences in GBM Biology reported in the last ten years and summarized the available information that may point towards a patient-tailored GBM therapy.

Results

Radiomics analyses have revealed that imaging parameters predict OS and treatment response of GBM patients in a sex-specific manner. Moreover, gender-based analysis of the transcriptome GBM tumors has found differential expression of various genes, potentially impacting the OS survival of patients in a sex-dependent manner. In addition to gene expression differences, the timing (subclonal or clonal) of the acquisition of common GBM-driver mutations, metabolism requirements, and immune landscape of these tumors has also been shown to be sex-specific, leading to a differential therapeutic response by sex. In male patients, transformed astrocytes are more sensitive to glutaminase 1 (GLS1) inhibition due to increased requirements for glutamine uptake. In female patients, GBM is more sensitive to anti-IL1β due to an increased population of circulating granulocytic myeloid-derived suppressor cells (gMDSC).

Conclusion

Moving forward, continued elucidation of GBM sexual dimorphism will be critical in improving the OS of GBM patients by ensuring that treatment plans are structured to exploit these sex-specific, molecular vulnerabilities in GBM tumors.

Advances in glioma models using in vivo electroporation to highjack neurodevelopmental processes

Glioma is the most prevalent type of neurological malignancies. Despite decades of efforts in neurosurgery, chemotherapy and radiation therapy, glioma remains one of the most treatment-resistant brain tumors with unfavorable outcomes. Recent progresses in genomic and epigenetic profiling have revealed new concepts of genetic events involved in the etiology of gliomas in humans, meanwhile, revolutionary technologies in gene editing and delivery allows to code these genetic "events" in animals to genetically engineer glioma models. This approach models the initiation and progression of gliomas in a natural microenvironment with an intact immune system and facilitates probing therapeutic strategies. In this review, we focus on recent advances in in vivo electroporation-based glioma modeling and outline the established genetically engineered glioma models (GEGMs).

Sex difference and immunosenescence affect transplantation outcomes

Kidney transplantation is a well-established alternative to renal replacement therapy. Although the number of patients with end-stage renal disease (ESRD) is increasing, the availability of kidney for transplantation is still insufficient to meet the needs. As age increases, the prevalence of ESRD increases; thus, the population of aged donors and recipients occupies large proportion. Accumulated senescent cells secrete pro-inflammatory factors and induce senescence. Additionally, it is gradually becoming clear that biological sex differences can influence aging and cause differences in senescence. Here, we review whether age-related sex differences affect organ transplant outcomes and what should be done in the future.

Sex specific regulation of TSPY-Like 2 in the DNA damage response of cancer cells

Females have a lower probability to develop somatic cancers and a better response to chemotherapy than males. However, the reasons for these differences are still not well understood. The X-linked gene TSPY-Like 2 (TSPYL2) encodes for a putative tumor suppressor protein involved in cell cycle regulation and DNA damage response (DDR) pathways. Here, we demonstrate that in unstressed conditions TSPYL2 is maintained at low levels by MDM2-dependent ubiquitination and proteasome degradation. Upon genotoxic stress, E2F1 promotes TSPYL2 expression and protein accumulation in non-transformed cell lines. Conversely, in cancer cells, TSPYL2 accumulates only in females or in those male cancer cells that lost the Y-chromosome during the oncogenic process. Hence, we demonstrate that while TSPYL2 mRNA is induced in all the tested tumor cell lines after DNA damage, TSPYL2 protein stability is increased only in female cancer cells. Indeed, we found that TSPYL2 accumulation, in male cancer cells, is prevented by the Y-encoded protein SRY, which modulates MDM2 protein levels. In addition, we demonstrated that TSPYL2 accumulation is required to sustain cell growth arrest after DNA damage, possibly contributing to protect normal and female cancer cells from tumor progression. Accordingly, TSPYL2 has been found more frequently mutated in female-specific cancers. These findings demonstrate for the first time a sex-specific regulation of TSPYL2 in the DDR of cancer cells and confirm the existence of sexual dimorphism in DNA surveillance pathways.

Impact of age and gender on glioblastoma onset, progression, and management

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, while its frequency in pediatric patients is 10-15%. For this reason, age is considered one of the major risk factors for the development of GBM, as it correlates with cellular aging phenomena involving glial cells and favoring the process of tumor transformation. Gender differences have been also identified, as the incidence of GBM is higher in males than in females, coupled with a worse outcome. In this review, we analyze age- and gender- dependent differences in GBM onset, mutational landscape, clinical manifestations, and survival, according to the literature of the last 20 years, focusing on the major risk factors involved in tumor development and on the mutations and gene alterations most frequently found in adults vs young patients and in males vs females. We then highlight the impact of age and gender on clinical manifestations and tumor localization and their involvement in the time of diagnosis and in determining the tumor prognostic value.

Abnormal expression of cortical cell cycle regulators underlying anxiety and depressive-like behavior in mice exposed to chronic stress

Background

The cell cycle is a critical mechanism for proper cellular growth, development and viability. The p16^INK4a and p21^Waf1/Cip1 are important regulators of the cell cycle progression in response to internal and external stimuli (e.g., stress). Accumulating evidence indicates that the prefrontal cortex (PFC) is particularly vulnerable to stress, where stress induces, among others, molecular and morphological alterations, reflecting behavioral changes. Here, we investigated if the p16^INK4a and p21^Waf1/Cip1 expression are associated with behavioral outcomes.

Methods

Prefrontal cortex mRNA and protein levels of p16^INK4A and p21^Waf1/Cip1 of mice (six independent groups of C57BL/6J, eight mice/group, 50% female) exposed from 0 to 35 days of chronic restraint stress (CRS) were quantified by qPCR and Western Blot, respectively. Correlation analyses were used to investigate the associations between cyclin-dependent kinase inhibitors (CKIs) expression and anxiety- and depression-like behaviors.

Results

Our results showed that the PFC activated the cell cycle regulation pathways mediated by both CKIs p16^INK4A and p21^Waf1/Cip1 in mice exposed to CRS, with overall decreased mRNA expression and increased protein expression. Moreover, correlation analysis revealed that mRNA and protein levels are statistically significant correlated with anxiety and depressive-like behavior showing a greater effect in males than females.

Conclusion

Our present study extends the existing literature providing evidence that PFC cells respond to chronic stress exposure by overexpressing CKIs. Furthermore, our findings indicated that abnormal expression of p16^INK4A and p21^Waf1/Cip1 may significantly contribute to non-adaptive behavioral responses.

Sex differences in brain tumor glutamine metabolism reveal sex-specific vulnerabilities to treatment

BACKGROUND

Brain cancer incidence and mortality rates are greater in males. Understanding the molecular mechanisms that underlie those sex differences could improve treatment strategies. Although sex differences in normal metabolism are well described, it is currently unknown whether they persist in cancerous tissue.

METHODS

Using positron emission tomography (PET) imaging and mass spectrometry, we assessed sex differences in glioma metabolism in samples from affected individuals. We assessed the role of glutamine metabolism in male and female murine transformed astrocytes using isotope labeling, metabolic rescue experiments, and pharmacological and genetic perturbations to modulate pathway activity.

FINDINGS

We found that male glioblastoma surgical specimens are enriched for amino acid metabolites, including glutamine. Fluoroglutamine PET imaging analyses showed that gliomas in affected male individuals exhibit significantly higher glutamine uptake. These sex differences were well modeled in murine transformed astrocytes, in which male cells imported and metabolized more glutamine and were more sensitive to glutaminase 1 (GLS1) inhibition. The sensitivity to GLS1 inhibition in males was driven by their dependence on glutamine-derived glutamate for α-ketoglutarate synthesis and tricarboxylic acid (TCA) cycle replenishment. Females were resistant to GLS1 inhibition through greater pyruvate carboxylase (PC)-mediated TCA cycle replenishment, and knockdown of PC sensitized females to GLS1 inhibition.

CONCLUSION

Our results show that clinically important sex differences exist in targetable elements of metabolism. Recognition of sex-biased metabolism may improve treatments through further laboratory and clinical research.

FUNDING

This work was supported by NIH grants, Joshua's Great Things, the Siteman Investment Program, and the Barnard Research Fund.

Potentiation of temozolomide activity against glioblastoma cells by aromatase inhibitor letrozole

PURPOSE

The DNA alkylating agent temozolomide (TMZ), is the first-line therapeutic for the treatment of glioblastoma (GBM). However, its use is confounded by the occurrence of drug resistance and debilitating adverse effects. Previously, we observed that letrozole (LTZ), an aromatase inhibitor, has potent activity against GBM in pre-clinical models. Here, we evaluated the effect of LTZ on TMZ activity against patient-derived GBM cells.

METHODS

Employing patient-derived G76 (TMZ-sensitive), BT142 (TMZ-intermediately sensitive) and G43 and G75 (TMZ-resistant) GBM lines we assessed the influence of LTZ and TMZ on cell viability and neurosphere growth. Combination Index (CI) analysis was performed to gain quantitative insights of this interaction. We then assessed DNA damaging effects by conducting flow-cytometric analysis of ˠH2A.X formation and induction of apoptotic signaling pathways (caspase3/7 activity). The effects of adding estradiol on LTZ-induced cytotoxicity and DNA damage were also evaluated.

RESULTS

Co-treatment with LTZ at a non-cytotoxic concentration (40 nM) reduced TMZ IC50 by 8, 37, 240 and 640 folds in G76, BT-142, G43 and G75 cells, respectively. The interaction was deemed to be synergistic based on CI analysis. LTZ co-treatment also significantly increased DNA damaging effects of TMZ. Addition of estradiol abrogated these LTZ effects.

CONCLUSIONS

LTZ increases DNA damage and synergistically enhances TMZ activity in TMZ sensitive and TMZ-resistant GBM lines. These effects are abrogated by the addition of exogenous estradiol underscoring that the observed effects of LTZ may be mediated by estrogen deprivation. Our study provides a strong rationale for investigating the clinical potential of combining LTZ and TMZ for GBM therapy.

P16INK4A—More Than a Senescence Marker

Aging is a biological feature that is characterized by gradual degeneration of function in cells, tissues, organs, or an intact organism due to the accumulation of environmental factors and stresses with time. Several factors have been attributed to aging such as oxidative stress and augmented production or exposure to reactive oxygen species, inflammatory cytokines production, telomere shortening, DNA damage, and, importantly, the deposit of senescent cells. These are irreversibly mitotically inactive, yet metabolically active cells. The reason underlying their senescence lies within the extrinsic and the intrinsic arms. The extrinsic arm is mainly characterized by the expression and the secretory profile known as the senescence-associated secretory phenotype (SASP). The intrinsic arm results from the impact of several genes meant to regulate the cell cycle, such as tumor suppressor genes. P16^INK4A is a tumor suppressor and cell cycle regulator that has been linked to aging and senescence. Extensive research has revealed that p16 expression is significantly increased in senescent cells, as well as during natural aging or age-related pathologies. Based on this fact, p16 is considered as a specific biomarker for detecting senescent cells and aging. Other studies have found that p16 is not only a senescence marker, but also a protein with many functions outside of senescence and aging. In this paper, we discuss and shed light on several studies that show the different functions of p16 and provide insights in its role in several biological processes besides senescence and aging.

Gonadal sex patterns p21-induced cellular senescence in mouse and human glioblastoma

Males exhibit higher incidence and worse prognosis for the majority of cancers, including glioblastoma (GBM). Disparate survival may be related to sex-biased responses to treatment, including radiation. Using a mouse model of GBM, we show that female cells are more sensitive to radiation, and that senescence represents a major component of the radiation therapeutic response in both sexes. Correlation analyses revealed that the CDK inhibitor p21 and irradiation induced senescence were differentially regulated between male and female cells. Indeed, female cellular senescence was more sensitive to changes in p21 levels, a finding that was observed in wildtype and transformed murine astrocytes, as well as patient-derived GBM cell lines. Using a novel Four Core Genotypes model of GBM, we further show that sex differences in p21-induced senescence are patterned during early development by gonadal sex. These data provide a rationale for the further study of sex differences in radiation response and how senescence might be enhanced for radiation sensitization. The determination that p21 and gonadal sex are required for sex differences in radiation response will serve as a foundation for these future mechanistic studies.

The H3K27M mutation alters stem cell growth, epigenetic regulation, and differentiation potential

BACKGROUND

Neurodevelopmental disorders increase brain tumor risk, suggesting that normal brain development may have protective properties. Mutations in epigenetic regulators are common in pediatric brain tumors, highlighting a potentially central role for disrupted epigenetic regulation of normal brain development in tumorigenesis. For example, lysine 27 to methionine mutation (H3K27M) in the H3F3A gene occurs frequently in Diffuse Intrinsic Pontine Gliomas (DIPGs), the most aggressive pediatric glioma. As H3K27M mutation is necessary but insufficient to cause DIPGs, it is accompanied by additional mutations in tumors. However, how H3K27M alone increases vulnerability to DIPG tumorigenesis remains unclear.

RESULTS

Here, we used human embryonic stem cell models with this mutation, in the absence of other DIPG contributory mutations, to investigate how H3K27M alters cellular proliferation and differentiation. We found that H3K27M increased stem cell proliferation and stem cell properties. It interfered with differentiation, promoting anomalous mesodermal and ectodermal gene expression during both multi-lineage and germ layer-specific cell specification, and blocking normal differentiation into neuroectoderm. H3K27M mutant clones exhibited transcriptomic diversity relative to the more homogeneous wildtype population, suggesting reduced fidelity of gene regulation, with aberrant expression of genes involved in stem cell regulation, differentiation, and tumorigenesis. These phenomena were associated with global loss of H3K27me3 and concordant loss of DNA methylation at specific genes in H3K27M-expressing cells.

CONCLUSIONS

Together, these data suggest that H3K27M mutation disrupts normal differentiation, maintaining a partially differentiated state with elevated clonogenicity during early development. This disrupted response to early developmental cues could promote tissue properties that enable acquisition of additional mutations that cooperate with H3K27M mutation in genesis of DMG/DIPG. Therefore, this work demonstrates for the first time that H3K27M mutation confers vulnerability to gliomagenesis through persistent clonogenicity and aberrant differentiation and defines associated alterations of histone and DNA methylation.

Female Mice are More Resistant to the Mixed-Field (67% Neutron + 33% Gamma) Radiation-Induced Injury in Bone Marrow and Small Intestine than Male Mice due to Sustained Increases in G-CSF and the Bcl-2/Bax Ratio and Lower miR-34a and MAPK Activation

In nuclear and radiological incidents, overexposure to ionizing radiation is life-threatening. It is evident that radiation depletes blood cells and increases circulating cytokine/chemokine concentrations as well as mortality. While microglia cells of female mice have been observed to be less damaged by radiation than in male mice, it is unclear whether sex affects physio-pathological responses in the bone marrow (BM) and gastrointestinal system (GI). We exposed B6D2F1 male and female mice to 0, 1.5, 3, or 6 Gy with mixed-field radiation containing 67% neutron and 33% gamma at a dose rate of 0.6 Gy/min. Blood and tissues were collected on days 1, 4, and 7 postirradiation. Radiation increased cytokines/chemokines in the femurs and ilea of female and male mice in a dose-dependent manner. Cytokines and chemokines reached a peak on day 4 and declined on day 7 with the exception of G-CSF which continued to increase on day 7 in female mice but not in male mice. MiR-34a (a Bcl-2 inhibitor), G-CSF (a miR-34a inhibitor), MAPK activation (pro-cell death), and citrulline (a biomarker of entro-epithelial proliferation), active caspase-3 (a biomarker of apoptosis) and caspase-1activated gasdermin D (a pyroptosis biomarker) were measured in the sternum, femur BM and ileum. Sternum histopathology analysis with H&E staining and femur BM cell counts as well as Flt-3L showed that BM cellularity was not as diminished in females, with males showing a 50% greater decline on day 7 postirradiation, mainly mediated by pyroptosis as indicated by increased gasdermin D in femur BM samples. Ileum injury, such as villus height and crypt depth, was also 43% and 30%, respectively, less damaged in females than in males. The severity of injury in both sexes was consistent with the citrulline and active caspase-3 measurements as well as active caspase-1 and gasdermin D measurements, suggesting apoptosis and pyroptosis occurred. On day 7, G-CSF in the ileum of female mice continued to be elevated by sevenfold, whereas G-CSF in the ileum of male mice returned to baseline. Furthermore, G-CSF is known to inhibit miR-34a expression, which in ileum on day 1 displayed a 3- to 4-fold increase in female mice after mixed-field (67% neutron + 33% gamma) irradiation, as compared to a 5- to 9-fold increase in male mice. Moreover, miR-34a blocked Bcl-2 expression. Mixed-field (60% neutron + 33% gamma) radiation induced more Bcl-2 in females than in males. On day 7, AKT activation was found in the ileums of females and males. However, MAPK activation including ERK, JNK, and p38 showed no changes in the ileum of females (by 0-fold; P > 0.05), whereas the MAPK activation was increased in the ileum of males (by 100-fold; P < 0.05). Taken together, the results suggest that organ injury from mixed-field (67% neutron + 33% gamma) radiation is less severe in females than in males, likely due to increased G-CSF, less MAPK activation, low miR-34a and increased Bcl-2/Bax ratio.

Unexplored Functions of Sex Hormones in Glioblastoma Cancer Stem Cells

Biological sex impacts a wide array of molecular and cellular functions that impact organismal development and can influence disease trajectory in a variety of pathophysiological states. In nonreproductive cancers, epidemiological sex differences have been observed in a series of tumors, and recent work has identified previously unappreciated sex differences in molecular genetics and immune response. However, the extent of these sex differences in terms of drivers of tumor growth and therapeutic response is less clear. In glioblastoma (GBM), the most common primary malignant brain tumor, there is a male bias in incidence and outcome, and key genetic and epigenetic differences, as well as differences in immune response driven by immune-suppressive myeloid populations, have recently been revealed. GBM is a prototypic tumor in which cellular heterogeneity is driven by populations of therapeutically resistant cancer stem cells (CSCs) that underlie tumor growth and recurrence. There is emerging evidence that GBM CSCs may show a sex difference, with male tumor cells showing enhanced self-renewal, but how sex differences impact CSC function is not clear. In this mini-review, we focus on how sex hormones may impact CSCs in GBM and implications for other cancers with a pronounced CSC population. We also explore opportunities to leverage new models to better understand the contribution of sex hormones vs sex chromosomes to CSC function. With the rising interest in sex differences in cancer, there is an immediate need to understand the extent to which sex differences impact tumor growth, including effects on CSC function.

The spectrum of sex differences in cancer

Sex differences in cellular and systems biology have been evolutionarily selected to optimize reproductive success in all species with little (sperm) and big (ova) gamete producers. They are evident from the time of fertilization and accrue throughout development through genetic, epigenetic, and circulating sex hormone-dependent mechanisms. Among other effects, they significantly impact on chromatin organization, metabolism, cell cycle regulation, immunity, longevity, and cancer risk and survival. Sex differences in cancer should be expected and accounted for in basic, translational, and clinical oncology research.

GPER Agonist G-1 Disrupts Tubulin Dynamics and Potentiates Temozolomide to Impair Glioblastoma Cell Proliferation

Glioblastoma (GBM) is the most common brain tumor in adults, which is very aggressive, with a very poor prognosis that affects men twice as much as women, suggesting that female hormones (estrogen) play a protective role. With an in silico approach, we highlighted that the expression of the membrane G-protein-coupled estrogen receptor (GPER) had an impact on GBM female patient survival. In this context, we explored for the first time the role of the GPER agonist G-1 on GBM cell proliferation. Our results suggested that G-1 exposure had a cytostatic effect, leading to reversible G2/M arrest, due to tubulin polymerization blockade during mitosis. However, the observed effect was independent of GPER. Interestingly, G-1 potentiated the efficacy of temozolomide, the current standard chemotherapy treatment, since the combination of both treatments led to prolonged mitotic arrest, even in a temozolomide less-sensitive cell line. In conclusion, our results suggested that G-1, in combination with standard chemotherapy, might be a promising way to limit the progression and aggressiveness of GBM.

Sex- and mutation-specific p53 gain-of-function activity in gliomagenesis

In cancer, missense mutations in the DNA-binding domain of TP53 are common. They abrogate canonical p53 activity and frequently confer gain-of-oncogenic function (GOF) through localization of transcriptionally active mutant p53 to non-canonical genes. We found that several recurring p53 mutations exhibit a sex difference in frequency in patients with glioblastoma (GBM). In vitro and in vivo analysis of three mutations, p53^R172H, p53^Y202C, and p53^Y217C revealed unique interactions between cellular sex and p53 GOF mutations that determined each mutation's ability to transform male versus female primary mouse astrocytes. These phenotypic differences were correlated with sex- and p53 mutation- specific patterns of genomic localization to the transcriptional start sites of upregulated genes belonging to core cancer pathways. The promoter regions of these genes exhibited a sex difference in enrichment for different transcription factor DNA-binding motifs. Together, our data establish a novel mechanism for sex specific mutant p53 GOF activity in GBM with implications for all cancer.

Functional Characterization of Brain Tumor-Initiating Cells and Establishment of GBM Preclinical Models that Incorporate Heterogeneity, Therapy, and Sex Differences

Glioblastoma (GBM) is the most common primary brain cancer in adults where tumor cell heterogeneity and sex differences influence clinical outcomes. Here, we functionally characterize three male and three female patient-derived GBM cell lines, identify protumorigenic BTICs, and create novel male and female preclinical models of GBM. Cell lines were evaluated on the following features: proliferation, stemness, migration, tumorigenesis, clinical characteristics, and sensitivity to radiation, TMZ, rhTNFSF10 (rhTRAIL), and rhBMP4 All cell lines were classified as GBM according to epigenetic subtyping, were heterogenous and functionally distinct from one another, and re-capitulated features of the original patient tumor. In establishing male and female preclinical models, it was found that two male-derived GBM cell lines (QNS108 and QNS120) and one female-derived GBM cell line (QNS315) grew at a faster rate in female mice brains. One male-derived GBM cell line (QNS108) decreased survival in female mice in comparison with male mice. However, no survival differences were observed for mice injected with a female-derived cell line (QNS315). In summary, a panel of six GBM patient-derived cell lines were functionally characterized, and it was shown that BTIC lines can be used to construct sex-specific models with differential phenotypes for additional studies.

Sexual Differentiation Specifies Cellular Responses to DNA Damage

Significant sex differences exist across cellular, tissue organization, and body system scales to serve the distinct sex-specific functions required for reproduction. They are present in all animals that reproduce sexually and have widespread impacts on normal development, aging, and disease. Observed from the moment of fertilization, sex differences are patterned by sexual differentiation, a lifelong process that involves mechanisms related to sex chromosome complement and the epigenetic and acute activational effects of sex hormones. In this mini-review, we examine evidence for sex differences in cellular responses to DNA damage, their underlying mechanisms, and how they might relate to sex differences in cancer incidence and response to DNA-damaging treatments.

Nuclear receptor NR5A2 negatively regulates cell proliferation and tumor growth in nervous system malignancies

Nervous system malignancies are characterized by rapid progression and poor survival rates. These clinical observations underscore the need for novel therapeutic insights and pharmacological targets. To this end, here, we identify the orphan nuclear receptor NR5A2/LRH1 as a negative regulator of cancer cell proliferation and promising pharmacological target for nervous system-related tumors. In particular, clinical data from publicly available databases suggest that high expression levels of NR5A2 are associated with favorable prognosis in patients with glioblastoma and neuroblastoma tumors. Consistently, we experimentally show that NR5A2 is sufficient to strongly suppress proliferation of both human and mouse glioblastoma and neuroblastoma cells without inducing apoptosis. Moreover, short hairpin RNA-mediated knockdown of the basal expression levels of NR5A2 in glioblastoma cells promotes their cell cycle progression. The antiproliferative effect of NR5A2 is mediated by the transcriptional induction of negative regulators of the cell cycle, CDKN1A (encoding for p21cip1), CDKN1B (encoding for p27kip1) and Prox1 Interestingly, two well-established agonists of NR5A2, dilauroyl phosphatidylcholine (DLPC) and diundecanoyl phosphatidylcholine, are able to mimic the antiproliferative action of NR5A2 in human glioblastoma cells via the induction of the same critical genes. Most importantly, treatment with DLPC inhibits glioblastoma tumor growth in vivo in heterotopic and orthotopic xenograft mouse models. These data indicate a tumor suppressor role of NR5A2 in the nervous system and render this nuclear receptor a potential pharmacological target for the treatment of nervous tissue-related tumors.

Sex-Specific Differences in Glioblastoma

Sex differences have been well identified in many brain tumors. Even though glioblastoma (GBM) is the most common primary malignant brain tumor in adults and has the worst outcome, well-established differences between men and women are limited to incidence and outcome. Little is known about sex differences in GBM at the disease phenotype and genetical/molecular level. This review focuses on a deep understanding of the pathophysiology of GBM, including hormones, metabolic pathways, the immune system, and molecular changes, along with differences between men and women and how these dimorphisms affect disease outcome. The information analyzed in this review shows a greater incidence and worse outcome in male patients with GBM compared with female patients. We highlight the protective role of estrogen and the upregulation of androgen receptors and testosterone having detrimental effects on GBM. Moreover, hormones and the immune system work in synergy to directly affect the GBM microenvironment. Genetic and molecular differences have also recently been identified. Specific genes and molecular pathways, either upregulated or downregulated depending on sex, could potentially directly dictate GBM outcome differences. It appears that sexual dimorphism in GBM affects patient outcome and requires an individualized approach to management considering the sex of the patient, especially in relation to differences at the molecular level.

The evolution of the cancer stem cell state in glioblastoma: emerging insights into the next generation of functional interactions

Cellular heterogeneity is a hallmark of advanced cancers and has been ascribed in part to a population of self-renewing, therapeutically resistant cancer stem cells (CSCs). Glioblastoma (GBM), the most common primary malignant brain tumor, has served as a platform for the study of CSCs. In addition to illustrating the complexities of CSC biology, these investigations have led to a deeper understanding of GBM pathogenesis, revealed novel therapeutic targets, and driven innovation towards the development of next-generation therapies. While there continues to be an expansion in our knowledge of how CSCs contribute to GBM progression, opportunities have emerged to revisit this conceptual framework. In this review, we will summarize the current state of CSCs in GBM using key concepts of evolution as a paradigm (variation, inheritance, selection, and time) to describe how the CSC state is subject to alterations of cell intrinsic and extrinsic interactions that shape their evolutionarily trajectory. We identify emerging areas for future consideration, including appreciating CSCs as a cell state that is subject to plasticity, as opposed to a discrete population. These future considerations will not only have an impact on our understanding of this ever-expanding field but will also provide an opportunity to inform future therapies to effectively treat this complex and devastating disease.

Brd4-bound enhancers drive cell-intrinsic sex differences in glioblastoma

Consistent sex differences in incidence and outcome have been reported in numerous cancers including brain tumors. GBM, the most common and aggressive primary brain tumor, occurs with higher incidence and shorter survival in males compared to females. Brd4 is essential for regulating transcriptome-wide gene expression and specifying cell identity, including that of GBM. We report that sex-biased Brd4 activity drives sex differences in GBM and renders male and female tumor cells differentially sensitive to BET inhibitors. The observed sex differences in BETi treatment strongly indicate that sex differences in disease biology translate into sex differences in therapeutic responses. This has critical implications for clinical use of BET inhibitors further affirming the importance of inclusion of sex as a biological variable.

Sex can be an important determinant of cancer phenotype, and exploring sex-biased tumor biology holds promise for identifying novel therapeutic targets and new approaches to cancer treatment. In an established isogenic murine model of glioblastoma (GBM), we discovered correlated transcriptome-wide sex differences in gene expression, H3K27ac marks, large Brd4-bound enhancer usage, and Brd4 localization to Myc and p53 genomic binding sites. These sex-biased gene expression patterns were also evident in human glioblastoma stem cells (GSCs). These observations led us to hypothesize that Brd4-bound enhancers might underlie sex differences in stem cell function and tumorigenicity in GBM. We found that male and female GBM cells exhibited sex-specific responses to pharmacological or genetic inhibition of Brd4. Brd4 knockdown or pharmacologic inhibition decreased male GBM cell clonogenicity and in vivo tumorigenesis while increasing both in female GBM cells. These results were validated in male and female patient-derived GBM cell lines. Furthermore, analysis of the Cancer Therapeutic Response Portal of human GBM samples segregated by sex revealed that male GBM cells are significantly more sensitive to BET (bromodomain and extraterminal) inhibitors than are female cells. Thus, Brd4 activity is revealed to drive sex differences in stem cell and tumorigenic phenotypes, which can be abrogated by sex-specific responses to BET inhibition. This has important implications for the clinical evaluation and use of BET inhibitors.

POT1 Regulates Proliferation and Confers Sexual Dimorphism in Glioma

Germline POT1 mutations are found in a spectrum of cancers and confer increased risk. Recently, we identified a series of novel germline POT1 mutations that predispose carrier families to the development of glioma. Despite these strong associations, how these glioma-associated POT1 mutations contribute to glioma tumorigenesis remains undefined. Here we show that POT1-G95C increases proliferation in glioma-initiating cells in vitro and in progenitor populations in the developing brain. In a native mouse model of glioma, loss of Pot1a/b resulted in decreased survival in females compared with males. These findings were corroborated in human glioma, where low POT1 expression correlated with decreased survival in females. Transcriptomic and IHC profiling of Pot1a/b-deficient glioma revealed that tumors in females exhibited decreased expression of immune markers and increased expression of cell-cycle signatures. Similar sex-dependent trends were observed in human gliomas that had low expression of POT1. Together, our studies demonstrate context-dependent functions for POT1 mutation or loss in driving progenitor proliferation in the developing brain and sexual dimorphism in glioma. SIGNIFICANCE: This study shows that manipulation of POT1 expression in glioma has sex-specific effects on tumorigenesis and associated immune signatures.

Impact of sex in the prevalence and progression of glioblastomas: the role of gonadal steroid hormones

BACKGROUND

As in other types of cancers, sex is an essential factor in the origin and progression of glioblastomas. Research in the field of endocrinology and cancer suggests that gonadal steroid hormones play an important role in the progression and prevalence of glioblastomas. In the present review, we aim to discuss the actions and mechanism triggered by gonadal steroid hormones in glioblastomas.

MAIN BODY

Glioblastoma is the most common malignant primary brain tumor. According to the epidemiological data, glioblastomas are more frequent in men than in women in a 1.6/1 proportion both in children and adults. This evidence, and the knowledge about sex influence over the prevalence of countless diseases, suggest that male gonadal steroid hormones, such as testosterone, promote glioblastomas growth. In contrast, a protective role of female gonadal steroid hormones (estradiol and progesterone) against glioblastomas has been questioned. Several pieces of evidence demonstrate a variety of effects induced by female and male gonadal steroid hormones in glioblastomas. Several studies indicate that pregnancy, a physiological state with the highest progesterone and estradiol levels, accelerates the progression of low-grade astrocytomas to glioblastomas and increases the symptoms associated with these tumors. In vitro studies have demonstrated that progesterone has a dual role in glioblastoma cells: physiological concentrations promote cell proliferation, migration, and invasion while very high doses (out physiological range) reduce cell proliferation and increases cell death.

CONCLUSION

Gonadal steroid hormones can stimulate the progression of glioblastomas through the increase in proliferation, migration, and invasion. However, the effects mentioned above depend on the concentrations of these hormones and the receptor involved in hormone actions. Estradiol and progesterone can exert promoter or protective effects while the role of testosterone has been always associated to glioblastomas progression.

Sex-specific aspects of epidemiology, molecular genetics and outcome: primary brain tumours

Recent years have seen a great interest in sex-specific aspects of many diseases, including cancer, in part because of the assumption that females have often not been adequately represented in early drug development and determination of safety, tolerability and efficacy in clinical trials. Brain tumours represent a highly heterogeneous group of neoplastic diseases with strong variation of incidence by age, but partly also by sex. Most gliomas are more common in men whereas meningiomas, the most common primary intracranial tumours, are more common in females. Potential sex-specific genetic risk factors and specific sex biology have been reported in a tumour-specific manner. Several small studies have indicated differences in tolerability and safety of, as well as benefit from, treatment by sex, but no conclusive data have been generated. Exploring sex-specific aspects of neuro-oncology should be studied more systematically and in more depth in order to uncover the biological reasons for known sex differences in this disease.

JAM-A functions as a female microglial tumor suppressor in glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most aggressive primary brain tumor and has a dismal prognosis. Previously, we identified that junctional adhesion molecule A (JAM-A), a cell adhesion molecule, is highly elevated in human GBM cancer stem cells and predicts poor patient prognosis. While JAM-A is also highly expressed in other cells in the tumor microenvironment, specifically microglia and macrophages, how JAM-A expression in these cells affects tumor growth has yet to be determined. The goal of this study was to understand the role of microenvironmental JAM-A in mediating GBM growth.

METHODS

Male and female wild-type (WT) and JAM-A-deficient mice were transplanted intracranially with the syngeneic glioma cell lines GL261 and SB28 and were assessed for differences in survival and microglial activation in tumors and in vitro. RNA-sequencing was performed to identify differentially regulated genes among all genotypes, and differences were validated in vitro and in vivo.

RESULTS

We found that JAM-A-deficient female mice succumbed to GBM more quickly compared with WT females and JAM-A-deficient and male WT mice. Analysis of microglia in the tumors revealed that female JAM-A-deficient microglia were more activated, and RNA-sequencing identified elevated expression of Fizz1 and Ifi202b specifically in JAM-A-deficient female microglia.

CONCLUSIONS

Our findings suggest that JAM-A functions to suppress pathogenic microglial activation in the female tumor microenvironment, highlighting an emerging role for sex differences in the GBM microenvironment and suggesting that sex differences extend beyond previously reported tumor cell-intrinsic differences.

Sex differences in health and disease: A review of biological sex differences relevant to cancer with a spotlight on glioma

The influence of biological sex differences on human health and disease, while being increasingly recognized, has long been underappreciated and underexplored. While humans of all sexes are more alike than different, there is evidence for sex differences in the most basic aspects of human biology and these differences have consequences for the etiology and pathophysiology of many diseases. In a disease like cancer, these consequences manifest in the sex biases in incidence and outcome of many cancer types. The ability to deliver precise, targeted therapies to complex cancer cases is limited by our current understanding of the underlying sex differences. Gaining a better understanding of the implications and interplay of sex differences in diseases like cancer will thus be informative for clinical practice and biological research. Here we review the evidence for a broad array of biological sex differences in humans and discuss how these differences may relate to observed sex differences in various diseases, including many cancers and specifically glioblastoma. We focus on areas of human biology that play vital roles in healthy and disease states, including metabolism, development, hormones, and the immune system, and emphasize that the intersection of sex differences in these areas should not go overlooked. We further propose that mathematical approaches can be useful for exploring the extent to which sex differences affect disease outcomes and accounting for those in the development of therapeutic strategies.

The impact of sex on hepatotoxic, inflammatory and proliferative responses in mouse models of liver carcinogenesis

Liver cancer is the third most common cause of cancer-related death but is almost 4-fold more prevalent in men than in women. Increased risk in men may be due in part to elevated chronic inflammation, which is a crucial driving force for many cancers. Male mice also have a greater incidence of liver cancer than females after postnatal exposure to procarcinogens such as 4-aminobiphenyl (ABP) or diethylnitrosamine (DEN), or in mice that transgenically express hepatitis B virus (HBV) proteins. Liver damage, inflammation and proliferation are central to liver cancer development, and previous studies have shown that hepatocellular damage, inflammation and proliferation are acutely elevated to a greater extent in adult male mice than in females after high-dose exposure to DEN. In contrast, postnatal exposure of mice to tumor-inducing doses of either DEN or ABP produces no such acute responses. However, it is not known whether sex differences in responses to postnatal carcinogen exposure or to HBV protein expression may develop over time following sexual maturation. We conducted an extended time course study to compare markers of liver damage, inflammation and proliferation between male and female mice exposed postnatally to 600 nmol ABP or 10 mg/kg DEN, and also in HBV transgenic (HBVTg) mice, over the duration of time that mice are normally maintained for standard liver tumor development protocols. Postnatal exposure to either ABP or DEN produced no evidence of either acute or chronic hepatocyte damage, liver inflammation or proliferation in either male or female mice. In contrast, HBVTg mice showed increased liver damage, inflammation and proliferation with age, but with no observed sex difference. These findings suggest that although chronic liver damage, inflammation and proliferation may be drivers for liver cancer development, they are unlikely to contribute directly to observed sex differences in liver tumor risk.

Sex Differences in Cancer Incidence and Survival: A Pan-Cancer Analysis

BACKGROUND

Sex plays an important role in the incidence, prognosis, and mortality of cancers, but often is not considered in disease treatment.

METHODS

We quantified sex differences in cancer incidence using the United States Cancer Statistics (USCS) public use database and sex differences in cancer survival using Surveillance, Epidemiology, and End Results (SEER) public use data from 2001 to 2016. Age-adjusted male-to-female incidence rate ratios (IRR) with 95% confidence intervals (CI) were generated by primary cancer site, race, and age groups. In addition, age-adjusted hazard ratios with 95% CI by sex within site were generated.

RESULTS

In general, cancer incidence and overall survival were lower in males than females, with Kaposi sarcoma (IRR: 9.751; 95% CI, 9.287-10.242; P < 0.001) having highest male-to-female incidence, and thyroid cancers (HR, 1.774; 95% CI, 1.707-1.845) having largest male-to-female survival difference. Asian or Pacific Islanders had particularly high male-to-female incidence in larynx cancers (IRR: 8.199; 95% CI, 7.203-9.363; P < 0.001), relative to other races. Among primary brain tumors, germ cell tumors had the largest male-to-female incidence (IRR: 3.03; 95% CI, 2.798-3.284, P < 0.001).

CONCLUSIONS

Overall, incidence and survival of cancer vary significantly by sex, with males generally having lower incidence and survival compared with females. Male-to-female incidence differences were also noted across race and age groups. These results provide strong evidence that the fundamental biology of sex differences affects cancers of all types.

IMPACT

This study represents the most recent and comprehensive reporting of sex differences in cancer incidence and survival in the United States. Identifying disadvantaged groups is critical as it can provide useful information to improve cancer survival, as well as to better understand the etiology and pathogenesis of specific cancers.

Myeloid-Derived Suppressor Cell Subsets Drive Glioblastoma Growth in a Sex-Specific Manner

Myeloid-derived suppressor cells (MDSC) that block antitumor immunity are elevated in glioblastoma (GBM) patient blood and tumors. However, the distinct contributions of monocytic (mMDSC) versus granulocytic (gMDSC) subsets have yet to be determined. In mouse models of GBM, we observed that mMDSCs were enriched in the male tumors, whereas gMDSCs were elevated in the blood of females. Depletion of gMDSCs extended survival only in female mice. Using gene-expression signatures coupled with network medicine analysis, we demonstrated in preclinical models that mMDSCs could be targeted with antiproliferative agents in males, whereas gMDSC function could be inhibited by IL1β blockade in females. Analysis of patient data confirmed that proliferating mMDSCs were predominant in male tumors and that a high gMDSC/IL1β gene signature correlated with poor prognosis in female patients. These findings demonstrate that MDSC subsets differentially drive immune suppression in a sex-specific manner and can be leveraged for therapeutic intervention in GBM. SIGNIFICANCE: Sexual dimorphism at the level of MDSC subset prevalence, localization, and gene-expression profile constitutes a therapeutic opportunity. Our results indicate that chemotherapy can be used to target mMDSCs in males, whereas IL1 pathway inhibitors can provide benefit to females via inhibition of gMDSCs.See related commentary by Gabrilovich et al., p. 1100.This article is highlighted in the In This Issue feature, p. 1079.

Sex differences in cancer mechanisms

We now know that cancer is many different diseases, with great variation even within a single histological subtype. With the current emphasis on developing personalized approaches to cancer treatment, it is astonishing that we have not yet systematically incorporated the biology of sex differences into our paradigms for laboratory and clinical cancer research. While some sex differences in cancer arise through the actions of circulating sex hormones, other sex differences are independent of estrogen, testosterone, or progesterone levels. Instead, these differences are the result of sexual differentiation, a process that involves genetic and epigenetic mechanisms, in addition to acute sex hormone actions. Sexual differentiation begins with fertilization and continues beyond menopause. It affects virtually every body system, resulting in marked sex differences in such areas as growth, lifespan, metabolism, and immunity, all of which can impact on cancer progression, treatment response, and survival. These organismal level differences have correlates at the cellular level, and thus, males and females can fundamentally differ in their protections and vulnerabilities to cancer, from cellular transformation through all stages of progression, spread, and response to treatment. Our goal in this review is to cover some of the robust sex differences that exist in core cancer pathways and to make the case for inclusion of sex as a biological variable in all laboratory and clinical cancer research. We finish with a discussion of lab- and clinic-based experimental design that should be used when testing whether sex matters and the appropriate statistical models to apply in data analysis for rigorous evaluations of potential sex effects. It is our goal to facilitate the evaluation of sex differences in cancer in order to improve outcomes for all patients.

Sex differences in GBM revealed by analysis of patient imaging, transcriptome, and survival data

Sex differences in the incidence and outcome of human disease are broadly recognized but, in most cases, not sufficiently understood to enable sex-specific approaches to treatment. Glioblastoma (GBM), the most common malignant brain tumor, provides a case in point. Despite well-established differences in incidence and emerging indications of differences in outcome, there are few insights that distinguish male and female GBM at the molecular level or allow specific targeting of these biological differences. Here, using a quantitative imaging-based measure of response, we found that standard therapy is more effective in female compared with male patients with GBM. We then applied a computational algorithm to linked GBM transcriptome and outcome data and identified sex-specific molecular subtypes of GBM in which cell cycle and integrin signaling are the critical determinants of survival for male and female patients, respectively. The clinical relevance of cell cycle and integrin signaling pathway signatures was further established through correlations between gene expression and in vitro chemotherapy sensitivity in a panel of male and female patient-derived GBM cell lines. Together, these results suggest that greater precision in GBM molecular subtyping can be achieved through sex-specific analyses and that improved outcomes for all patients might be accomplished by tailoring treatment to sex differences in molecular mechanisms.

PIK3CA variants selectively initiate brain hyperactivity during gliomagenesis

Glioblastoma is a universally lethal form of brain cancer that exhibits an array of pathophysiological phenotypes, many of which are mediated by interactions with the neuronal microenvironment1,2. Recent studies have shown that increases in neuronal activity have an important role in the proliferation and progression of glioblastoma3,4. Whether there is reciprocal crosstalk between glioblastoma and neurons remains poorly defined, as the mechanisms that underlie how these tumours remodel the neuronal milieu towards increased activity are unknown. Here, using a native mouse model of glioblastoma, we develop a high-throughput in vivo screening platform and discover several driver variants of PIK3CA. We show that tumours driven by these variants have divergent molecular properties that manifest in selective initiation of brain hyperexcitability and remodelling of the synaptic constituency. Furthermore, secreted members of the glypican (GPC) family are selectively expressed in these tumours, and GPC3 drives gliomagenesis and hyperexcitability. Together, our studies illustrate the importance of functionally interrogating diverse tumour phenotypes driven by individual, yet related, variants and reveal how glioblastoma alters the neuronal microenvironment.

Gliomas display distinct sex-based differential methylation patterns based on molecular subtype

Background

Gliomas are the most common type of primary brain tumor and one of many cancers where males are diagnosed with greater frequency than females. However, little is known about the sex-based molecular differences in glioblastomas (GBMs) or lower grade glioma (non-GBM) subtypes. DNA methylation is an epigenetic mechanism involved in regulating gene transcription. In glioma and other cancers, hypermethylation of specific gene promoters downregulates transcription and may have a profound effect on patient outcome. The purpose of this study was to determine if sex-based methylation differences exist in different glioma subtypes.

Methods

Molecular and clinical data from glioma patients were obtained from The Cancer Genome Atlas and grouped according to tumor grade and molecular subtype (IDH1/2 mutation and 1p/19q chromosomal deletion). Sex-specific differentially methylated probes (DMPs) were identified in each subtype and further analyzed to determine if they were part of differentially methylated regions (DMRs) or associated with differentially methylated DNA transcription regulatory binding motifs.

Results

Analysis of methylation data in 4 glioma subtypes revealed unique sets of both sex-specific DMPs and DMRs in each subtype. Motif analysis based on DMP position also identified distinct sex-based sets of DNA-binding motifs that varied according to glioma subtype. Downstream targets of 2 of the GBM-specific transcription binding sites, NFAT5 and KLF6, showed differential gene expression consistent with increased methylation mediating downregulation.

Conclusion

DNA methylation differences between males and females in 4 glioma molecular subtypes suggest an important, sex-specific role for DNA methylation in epigenetic regulation of gliomagenesis.

Identification of cancer sex-disparity in the functional integrity of p53 and its X chromosome network

The disproportionately high prevalence of male cancer is poorly understood. We tested for sex-disparity in the functional integrity of the major tumor suppressor p53 in sporadic cancers. Our bioinformatics analyses expose three novel levels of p53 impact on sex-disparity in 12 non-reproductive cancer types. First, TP53 mutation is more frequent in these cancers among US males than females, with poorest survival correlating with its mutation. Second, numerous X-linked genes are associated with p53, including vital genomic regulators. Males are at unique risk from alterations of their single copies of these genes. High expression of X-linked negative regulators of p53 in wild-type TP53 cancers corresponds with reduced survival. Third, females exhibit an exceptional incidence of non-expressed mutations among p53-associated X-linked genes. Our data indicate that poor survival in males is contributed by high frequencies of TP53 mutations and an inability to shield against deregulated X-linked genes that engage in p53 networks.

Blockade of a Laminin-411-Notch Axis with CRISPR/Cas9 or a Nanobioconjugate Inhibits Glioblastoma Growth through Tumor-Microenvironment Cross-talk

There is an unmet need for the treatment of glioblastoma multiforme (GBM). The extracellular matrix, including laminins, in the tumor microenvironment is important for tumor invasion and progression. In a panel of 226 patient brain glioma samples, we found a clinical correlation between the expression of tumor vascular laminin-411 (α4β1γ1) with higher tumor grade and with expression of cancer stem cell (CSC) markers, including Notch pathway members, CD133, Nestin, and c-Myc. Laminin-411 overexpression also correlated with higher recurrence rate and shorter survival of GBM patients. We also showed that depletion of laminin-411 α4 and β1 chains with CRISPR/Cas9 in human GBM cells led to reduced growth of resultant intracranial tumors in mice and significantly increased survival of host animals compared with mice with untreated cells. Inhibition of laminin-411 suppressed Notch pathway in normal and malignant human brain cell types. A nanobioconjugate potentially suitable for clinical use and capable of crossing blood-brain barrier was designed to block laminin-411 expression. Nanobioconjugate treatment of mice carrying intracranial GBM significantly increased animal survival and inhibited multiple CSC markers, including the Notch axis. This study describes an efficient strategy for GBM treatment via targeting a critical component of the tumor microenvironment largely independent of heterogeneous genetic mutations in glioblastoma.Significance: Laminin-411 expression in the glioma microenvironment correlates with Notch and other cancer stem cell markers and can be targeted by a novel, clinically translatable nanobioconjugate to inhibit glioma growth.