Impact of Docetaxel on blood-brain barrier function and formation of breast cancer brain metastases

Neurobehavioral manifestations in female rats after intermittent exposure to an anticancer agent, paclitaxel

Paclitaxel (PTX), a widely used chemotherapeutic agent, causes both peripheral and central neurotoxicity, leading to significant behavioral impairments. However, inadequate literature is available on PTX-induced neurobehavioral sequelae associated with anxiety, depression, and cognition in adults during and after chemotherapy. Therefore, the present study aimed to investigate neurobehavioral impairments in adult female rats following PTX exposure, with a specific focus on anxiety-like behaviors and cognitive functions such as learning and memory. In this study, we used adult female Wistar rats aged 10-12 weeks (average weight: 180 ± 5 g) and administered clinically relevant therapeutic doses of PTX (1.6 and 3.2 mg/kg body weight) intravenously once weekly for 6 weeks, simulating the clinical chemotherapy regimen. Neurobehavioral assessments were conducted after the first and sixth doses of PTX using validated mazes, including the photoactometer, open-field maze, elevated plus-maze (EPM; for anxiety-like behaviors), and the step-down latency test (SDL; for cognitive performance). Neurobehavioral patterns were recorded using autotracking software (ANY-maze, Stoelting Co., Wood Dale, Illinois, USA). Our findings revealed substantially reduced locomotor activity in the photoactometer, increased anxiety-like behaviors with amplified fear emotionality in the open-field and EPM tests, and memory impairment in the SDL test. These results suggest that the manifestation of anxiogenic and cognitive behavioral changes is associated with the administration of a higher dose (3.2 mg/kg) of PTX. In conclusion, our study indicates that PTX causes significant neurobehavioral impairments in rats after exposure to equivalent therapeutic doses of PTX.

Central Nervous System Toxicity in Prostate Cancer Patients Treated with Androgen Receptor Signaling Inhibitors: A Systematic Review, Meta-analysis, and Network Meta-analysis

BACKGROUND

Androgen-receptor signaling inhibitors (ARSIs) significantly improve survival in systemic therapy for advanced/metastatic prostate cancer (PCa) patients; however possible central nervous system (CNS) toxicity is an unaddressed concern. We aimed to assess and compare the incidence of CNS-related adverse events (AEs) secondary to the treatment of PCa patients with different ARSIs.

MATERIALS

In August 2023, a comprehensive seach was conducted in three databases for randomized controlled trials (RCTs) of PCa patients receiving ARSIs plus ADT. The primary endpoints included mental impairment, cognitive impairment, seizure, fatigue, and falls.

RESULTS

Twenty-six RCTs, comprising 20,328 patients, were included in meta-analyses and network meta-analyses (NMAs). ARSIs increased the risk of mental impairment (RR: 1.72; 95% CI, 1.09-2.71), cognitive impairment (RR: 2.25; 95% CI, 1.78-2.86), seizure (RR: 2.20, 95% CI, 1.09-4.45), fatigue (RR: 1.31, 95% CI, 1.20-1.43), and falls (RR: 2.07, 95% CI, 1.60-2.67) compared to standard of care (SOC). Based on NMAs, Enzalutamide showed a significant increase in risk for all assessed CNS-related AEs, while Abiraterone demonstrated significant risk increases in cognitive impairment, fatigue, and falls. Conversely, Darolutamide did not exhibit significant increases in risk for any CNS-related AEs, except for fatigue.

CONCLUSIONS

The addition of ARSIs to ADT increased all examined CNS-related AEs compared to SOC. Each ARSI is associated with a distinct profile of CNS-related AEs. Careful patient selection and monitoring for CNS sequelae is necessary to achieve the best quality of life in patients on ARSI + ADT for PCa.

Prognostic Factors in Therapy Regimes of Breast Cancer Patients with Brain Metastases: A Retrospective Monocentric Analysis

Background: Breast cancer patients who develop brain metastases have a high mortality rate and a massive decrease in quality of life. Approximately 10-15% of all patients with breast cancer (BC) and 5-40% of all patients with metastatic BC develop brain metastasis (BM) during the course of the disease. However, there is only limited knowledge about prognostic factors in the treatment of patients with brain metastases in breast cancer (BMBC). Therefore, we retrospectively analyzed data of BMBC patients from the University Hospital of Würzburg for treatment patterns to find characteristics associated with a better or worse prognosis. These findings should help to treat the ever-increasing collective of patients with BMBC better in the future. Methods: The clinical data of 337 patients with cerebral metastatic breast cancer (date of death between 2004 and 2021) treated at the Department of Gynecology and Obstetrics of the University Hospital Würzburg were retrospectively analyzed, with a focus on patients' survival. Results: The involvement of regional lymph nodes at initial diagnosis, the immunohistochemical subtype of TNBC at the onset of BMBC, and extracranial metastases at the time of BM diagnosis (bone, liver, lung metastases) were associated with a worse prognosis. In contrast, the immunohistochemical subtype of HER2/neu, the sole occurrence of a singular BM, the local surgical removal of BMs, and radiotherapy (especially stereotactic radiotherapy) were associated with prolonged survival. The number of therapies before the diagnosis of BMs also had a prognostic influence. Conclusions: Looking back at data is crucial for pinpointing risk elements affecting survival after a BM diagnosis. In our investigation, along with established factors like immunohistologic subtype, BM count, surgical excision, stereotactic irradiation, and type of extracranial metastasis, we also found that the number of therapies before BM diagnosis and the initial lymph node status were associated with patients' survival. Potentially, these factors could be included in prospective prognostic scores for evaluating brain metastasis survival rates, thereby aiding in making appropriate treatment suggestions for impacted patients.

Genetic and clinical correlates of two neuroanatomical AI dimensions in the Alzheimer's disease continuum

Alzheimer's disease (AD) is associated with heterogeneous atrophy patterns. We employed a semi-supervised representation learning technique known as Surreal-GAN, through which we identified two latent dimensional representations of brain atrophy in symptomatic mild cognitive impairment (MCI) and AD patients: the "diffuse-AD" (R1) dimension shows widespread brain atrophy, and the "MTL-AD" (R2) dimension displays focal medial temporal lobe (MTL) atrophy. Critically, only R2 was associated with widely known sporadic AD genetic risk factors (e.g., APOE ε4) in MCI and AD patients at baseline. We then independently detected the presence of the two dimensions in the early stages by deploying the trained model in the general population and two cognitively unimpaired cohorts of asymptomatic participants. In the general population, genome-wide association studies found 77 genes unrelated to APOE differentially associated with R1 and R2. Functional analyses revealed that these genes were overrepresented in differentially expressed gene sets in organs beyond the brain (R1 and R2), including the heart (R1) and the pituitary gland, muscle, and kidney (R2). These genes were enriched in biological pathways implicated in dendritic cells (R2), macrophage functions (R1), and cancer (R1 and R2). Several of them were "druggable genes" for cancer (R1), inflammation (R1), cardiovascular diseases (R1), and diseases of the nervous system (R2). The longitudinal progression showed that APOE ε4, amyloid, and tau were associated with R2 at early asymptomatic stages, but this longitudinal association occurs only at late symptomatic stages in R1. Our findings deepen our understanding of the multifaceted pathogenesis of AD beyond the brain. In early asymptomatic stages, the two dimensions are associated with diverse pathological mechanisms, including cardiovascular diseases, inflammation, and hormonal dysfunction-driven by genes different from APOE-which may collectively contribute to the early pathogenesis of AD. All results are publicly available at https://labs-laboratory.com/medicine/ .

The Role of Microglia in Brain Metastases: Mechanisms and Strategies

Brain metastases and related complications are one of the major fatal factors in cancer. Patients with breast cancer, lung cancer, and melanoma are at a high risk of developing brain metastases. However, the mechanisms underlying the brain metastatic cascade remain poorly understood. Microglia, one of the major resident macrophages in the brain parenchyma, are involved in multiple processes associated with brain metastasis, including inflammation, angiogenesis, and immune modulation. They also closely interact with metastatic cancer cells, astrocytes, and other immune cells. Current therapeutic approaches against metastatic brain cancers, including small-molecule drugs, antibody-coupled drugs (ADCs), and immune-checkpoint inhibitors (ICIs), have compromised efficacy owing to the impermeability of the blood-brain barrier (BBB) and complex brain microenvironment. Targeting microglia is one of the strategies for treating metastatic brain cancer. In this review, we summarize the multifaceted roles of microglia in brain metastases and highlight them as potential targets for future therapeutic interventions.

Experimental models for cancer brain metastasis

Brain metastases are a leading cause of cancer-related mortality. However, progress in their treatment has been limited over the past decade, due to an incomplete understanding of the underlying biological mechanisms. Employing accurate in vitro and in vivo models to recapitulate the complexities of brain metastasis offers the most promising approach to unravel the intricate cellular and physiological processes involved. Here, we present a comprehensive review of the currently accessible models for studying brain metastasis. We introduce a diverse array of in vitro and in vivo models, including cultured cells using the Transwell system, organoids, microfluidic models, syngeneic models, xenograft models, and genetically engineered models. We have also provided a concise summary of the merits and limitations inherent to each model while identifying the optimal contexts for their effective utilization. This review serves as a comprehensive resource, aiding researchers in making well-informed decisions regarding model selection that align with specific research questions.

Molecular signaling network and therapeutic developments in breast cancer brain metastasis

Breast cancer (BC) is one of the most frequently diagnosed cancers in women worldwide. It has surpassed lung cancer as the leading cause of cancer-related death. Breast cancer brain metastasis (BCBM) is becoming a major clinical concern that is commonly associated with ER-ve and HER2+ve subtypes of BC patients. Metastatic lesions in the brain originate when the cancer cells detach from a primary breast tumor and establish metastatic lesions and infiltrate near and distant organs via systemic blood circulation by traversing the BBB. The colonization of BC cells in the brain involves a complex interplay in the tumor microenvironment (TME), metastatic cells, and brain cells like endothelial cells, microglia, and astrocytes. BCBM is a significant cause of morbidity and mortality and presents a challenge to developing successful cancer therapy. In this review, we discuss the molecular mechanism of BCBM and novel therapeutic strategies for patients with brain metastatic BC.

A flow cytometry-based protocol for syngenic isolation of neurovascular unit cells from mouse and human tissues

The neurovascular unit (NVU), composed of endothelial cells, pericytes, juxtaposed astrocytes and microglia together with neurons, is essential for proper central nervous system functioning. The NVU critically regulates blood-brain barrier (BBB) function, which is impaired in several neurological diseases and is therefore a key therapeutic target. To understand the extent and cellular source of BBB dysfunction, simultaneous isolation and analysis of NVU cells is needed. Here, we describe a protocol for the EPAM-ia method, which is based on flow cytometry for simultaneous isolation and analysis of endothelial cells, pericytes, astrocytes and microglia. This method is based on differential processing of NVU cell types using enzymes, mechanical homogenization and filtration specific for each cell type followed by combining them for immunostaining and fluorescence-activated cell sorting. The gating strategy encompasses cell-type-specific and exclusion markers for contaminating cells to isolate the major NVU cell types. This protocol takes ~6 h for two sets of one or two animals. The isolation part requires experience in animal handling, fresh tissue processing and immunolabeling for flow cytometry. Sorted NVU cells can be used for downstream applications including transcriptomics, proteomics and cell culture. Multiple cell-type analyses using UpSet can then be applied to obtain robust targets from single or multiple NVU cell types in neurological diseases associated with BBB dysfunction. The EPAM-ia method is also amenable to isolation of several other cell types, including cancer cells and immune cells. This protocol is applicable to healthy and pathological tissue from mouse and human sources and to several cell types compared with similar protocols.

The Journey of Cancer Cells to the Brain: Challenges and Opportunities

Cancer metastases into the brain constitute one of the most severe, but not uncommon, manifestations of cancer progression. Several factors control how cancer cells interact with the brain to establish metastasis. These factors include mediators of signaling pathways participating in migration, infiltration of the blood-brain barrier, interaction with host cells (e.g., neurons, astrocytes), and the immune system. Development of novel therapies offers a glimpse of hope for increasing the diminutive life expectancy currently forecasted for patients suffering from brain metastasis. However, applying these treatment strategies has not been sufficiently effective. Therefore, there is a need for a better understanding of the metastasis process to uncover novel therapeutic targets. In this review, we follow the journey of various cancer cells from their primary location through the diverse processes that they undergo to colonize the brain. These processes include EMT, intravasation, extravasation, and infiltration of the blood-brain barrier, ending up with colonization and angiogenesis. In each phase, we focus on the pathways engaging molecules that potentially could be drug target candidates.

Highlights in targeted nanoparticles as a delivery strategy for glioma treatment

Glioma is the most common type of Central Nervous System (CNS) neoplasia and it arises from glial cells. As glial cells are formed by different types of cells, glioma can be classified according to the cells that originate it or the malignancy grade. Glioblastoma multiforme is the most common and aggressive glioma. The high lethality of this tumor is related to the difficulty in performing surgical removal, chemotherapy, and radiotherapy in the CNS. To improve glioma treatment, a wide range of chemotherapeutics have been encapsulated in nanosystems to increase their ability to overcome the blood-brain barrier (BBB) and specifically reach the tumoral cells, reducing side effects and improving drug concentration in the tumor microenvironment. Several studies have investigated nanosystems covered with targeting ligands (e.g., proteins, peptides, aptamers, folate, and glucose) to increase the ability of drugs to cross the BBB and enhance their specificity to glioma through specific recognition by receptors on BBB and glioma cells. This review addresses the main targeting ligands used in nanosystems to overcome the BBB and promote the active targeting of drugs for glioma. Furthermore, the advantages of using these molecules in glioma treatment are discussed.

Redox imbalance induced by docetaxel in the neuroblastoma SH-SY5Y cells: a study of docetaxel-induced neuronal damage

Objectives

In cancer survivors, chemotherapy-associated adverse neurological effects are described as side effects in non-targeted tissue. We investigated the role of redox-imbalance in neuronal damage by a relative low dose of Docetaxel (DTX).

Methods

The neuroblastoma cells (SH-SY5Y cells) were exposed to DTX at a dose of 1.25 nM for 6 h. Antioxidant defenses (i.e. ascorbic acid, glutathione, and catalase) and lipid oxidation products (i.e. F₂-isoprostanes) were evaluated. To investigate cell ultrastructure and tubulin localisation, transmission electron microscopy (TEM) and immunofluorescence techniques were applied.

Results

In the SH-SY5Y cells, DTX induced a significant reduction of total glutathione (P < 0.001) and ascorbic acid (P < 0.05), and an increase in both total F₂-Isoprostanes (P < 0.05) and catalase activity (P < 0.05), as compared to untreated cells. Additionally, TEM showed a significant increase in cells with apoptotic characteristics. Immunolocalisation of tubulin showed a compromised cytoskeletal organisation.

Discussion

The investigated sublethal dose of DTX, to which non-targeted cells may be exposed throughout the duration of chemotherapy treatment, induces a redox imbalance resulting in a specific modulation of the antioxidant response. This study provides new insights into DTX-induced cellular mechanisms useful for evaluating whether the concomitant use of antioxidants associated with chemotherapy mitigates chemotherapy side effects in cancer survivors.

Brain Metastasis Cell Lines Panel: A Public Resource of Organotropic Cell Lines

Spread of cancer to the brain remains an unmet clinical need in spite of the increasing number of cases among patients with lung, breast cancer, and melanoma most notably. Although research on brain metastasis was considered a minor aspect in the past due to its untreatable nature and invariable lethality, nowadays, limited but encouraging examples have questioned this statement, making it more attractive for basic and clinical researchers. Evidences of its own biological identity (i.e., specific microenvironment) and particular therapeutic requirements (i.e., presence of blood-brain barrier, blood-tumor barrier, molecular differences with the primary tumor) are thought to be critical aspects that must be functionally exploited using preclinical models. We present the coordinated effort of 19 laboratories to compile comprehensive information related to brain metastasis experimental models. Each laboratory has provided details on the cancer cell lines they have generated or characterized as being capable of forming metastatic colonies in the brain, as well as principle methodologies of brain metastasis research. The Brain Metastasis Cell Lines Panel (BrMPanel) represents the first of its class and includes information about the cell line, how tropism to the brain was established, and the behavior of each model in vivo. These and other aspects described are intended to assist investigators in choosing the most suitable cell line for research on brain metastasis. The main goal of this effort is to facilitate research on this unmet clinical need, to improve models through a collaborative environment, and to promote the exchange of information on these valuable resources.

Stem cell therapies as a therapeutic option to counter chemo brain: a negative effect of cancer treatment

Chemo brain, a constellation of cognitive deficiencies followed by chemotherapy drugs, used to treat different types of cancers and adversely impacts the quality of life of a cancer survivor. The underlying mechanism of chemo brain remains vague, thus delaying the advancement of efficient treatments. Unfortunately, there is no US FDA approved medicine for chemo brain and often medicines considered for chemo brain are already the ones approved for other diseases. Nevertheless, researches exploring stem cell transplantation in different neurodegenerative diseases demonstrate that cellular transplantation could reverse chemotherapy-induced chemo brain. This review talks about the mechanism behind the cognitive impairments instigated by different chemotherapy drugs used in cancer treatment, and how stem cell therapy could be advantageous to overcome this disease.

Neratinib: the emergence of a new player in the management of HER2+ breast cancer brain metastasis

HER2-positive (HER2+) breast cancer has become an effectively treatable disease in the era of targeted therapies, and outcomes have improved such that prognosis of this subtype is demonstrated to be superior to HER2-negative disease. Despite these advances, durable responses in HER2+ metastatic disease are challenged by the increased risk for brain metastasis. Neratinib is an irreversible pan-HER kinase inhibitor that has emerged as an effective agent when combined with capecitabine for the management of HER2+ metastatic breast cancer patients with brain metastasis. The randomized, Phase III, NALA trial compares neratinib plus capecitabine to a currently prevailing regimen of lapatinib plus capecitabine and is provided herein. Analysis of NALA portends meaningful changes on the horizon for the management of HER2+ metastatic breast cancer.