A cell state-specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma.

Glioma cells hijack developmental programs to control cell state. Here, we uncover a glioma cell state-specific metabolic liability that can be therapeutically targeted. To model cell conditions at brain tumor inception, we generated genetically engineered murine gliomas, with deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling astrocyte differentiation during brain development. N1IC tumors harbored quiescent astrocyte-like transformed cell populations while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. Further, N1IC transformed cells exhibited increased mitochondrial lipid peroxidation, high ROS production and depletion of reduced glutathione. This altered mitochondrial phenotype rendered the astrocyte-like, quiescent populations more sensitive to pharmacologic or genetic inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Treatment of patient-derived early-passage cell lines and glioma slice cultures generated from surgical samples with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles. Collectively, these findings reveal a specific therapeutic vulnerability to ferroptosis linked to mitochondrial redox imbalance in a subpopulation of quiescent astrocyte-like glioma cells resistant to standard forms of treatment.

Optical Methods for Brain Tumor Detection: A Systematic Review.

Background: In brain tumor surgery, maximal tumor resection is typically desired. This is complicated by infiltrative tumor cells which cannot be visually distinguished from healthy brain tissue. Optical methods are an emerging field that can potentially revolutionize brain tumor surgery through intraoperative differentiation between healthy and tumor tissues. Methods: This study aimed to systematically explore and summarize the existing literature on the use of Raman Spectroscopy (RS), Hyperspectral Imaging (HSI), Optical Coherence Tomography (OCT), and Diffuse Reflectance Spectroscopy (DRS) for brain tumor detection. MEDLINE, Embase, and Web of Science were searched for studies evaluating the accuracy of these systems for brain tumor detection. Outcome measures included accuracy, sensitivity, and specificity. Results: In total, 44 studies were included, covering a range of tumor types and technologies. Accuracy metrics in the studies ranged between 54 and 100% for RS, 69 and 99% for HSI, 82 and 99% for OCT, and 42 and 100% for DRS. Conclusions: This review provides insightful evidence on the use of optical methods in distinguishing tumor from healthy brain tissue.

The role of systemic therapy in advanced skull base chordomas: overview of the current state and the MD Anderson protocol.

The role of systemic therapy in primary or advanced and metastatic chordoma has been traditionally limited because of the inherent resistance to cytotoxic therapies and lack of specific or effective therapeutic targets. Despite resection and adjuvant radiation therapy, local recurrence rates in clival chordoma remain high and the risk of systemic metastases is not trivial, leading to significant morbidity and mortality. Recently, molecular targeted therapies (MTTs) and immune checkpoint inhibitors (ICIs) have emerged as promising therapeutic avenues in chordoma. In recent years, preclinical studies have identified potential targets based on intrinsic genetic dependencies, epigenetic modulators, or newly identified tumor-associated cell populations driving treatment resistance and recurrence. Nonetheless, the role of systemic therapies in the neoadjuvant or adjuvant setting for primary, locally progressive, and distant metastatic chordomas is still being investigated. Herein, an overview of current and emerging systemic treatment strategies in advanced clival chordoma is provided. Furthermore, several molecular biomarkers have been recently uncovered as potential predictors of the response to specific molecular therapeutics. The authors describe the recently discovered role of 1p36 and 9p21 deletions as biomarkers capable of guiding drug selection. Then they discuss completed and ongoing clinical trials of MTTs, including several tyrosine kinase inhibitors used as monotherapy or in combination, such as imatinib, sorafenib, dasatinib, and lapatinib, among others, as well as mammalian target of rapamycin inhibitors such as everolimus and rapamycin. They present their experience and other recent studies demonstrating vast benefits in advanced chordoma from ICIs. Additionally, they provide a brief overview of novel systemic strategies such as adoptive cell transfer (CAR-T and NK cells), oncolytic viruses, epigenetic targeting (KDM6, HDAC, and EZH2 inhibitors), and several promising preclinical studies with high translational potential. Finally, the authors present their institutional multidisciplinary protocol for the incorporation of systemic therapy for both newly diagnosed and recurrent chordomas based on molecular studies including upfront enrollment in MTT trials in patients with epidermal growth factor receptor upregulation or INI-1 deficiency or enrollment in ICI clinical trials for patients with high tumor mutational burden or high PD-L1 expression on tumor cells or in the tumor microenvironment.