Anticancer Drugs and the Nervous System

Cancer and stroke: What do we know and where do we go?

Cancer is an increasingly recognized cause for ischemic stroke, with recent acknowledgement of cancer-related stroke as an emerging stroke subtype with unique pathophysiologic mechanisms. In addition, cancer-related stroke may differ from stroke in the general population as cancer patients may not receive guideline-recommended stroke care, and the occurrence of stroke may also preclude patients from receiving optimal cancer treatments. Due to the high degree of morbidity and mortality associated with both conditions, understanding the relationship between stroke and cancer is crucial. In this narrative review, we discuss the association between cancer and stroke, the unique pathophysiologic mechanisms underlying this phenomenon, treatment options including acute reperfusion therapies and secondary prevention strategies, compare outcomes between cancer-related stroke and stroke in the general population, and review new and emerging evidence in this field.

The role of neurologists in the era of cancer immunotherapy: Focus on CAR T-cell therapy and immune checkpoint inhibitors

Cancer immunotherapy represents a novel anticancer strategy that acts directly on the immune system, promoting its activation toward cancer cells to enhance its natural ability to fight cancer. Among various treatments currently used or investigated, chimeric antigen receptors (CAR) T-cell therapy and immune checkpoint inhibitors (ICIs) have consistently proven their efficacy. These innovations are progressively improving the standard of care in cancer treatment, yet they are hampered by novel neurological adverse events, attributing to neurologists a key role in the multidisciplinary oncological team. Indeed, neurotoxicity may develop in up to 77% of patients who received CAR T-cell therapy and usually presents with encephalopathy characterized by a predominant frontal lobe dysfunction. This neurotoxicity is related to cytokine release syndrome, a systemic hyperinflammatory condition triggered by CAR T-cells. On the other hand, following treatment with ICIs, unrestrained T-cells may lead to central and peripheral neurological disorders by antigen-directed autoimmunity. Notably, biological and clinical similarities have been underlined between neurotoxicity related to CAR T-cell therapy and neurological manifestations of cytokine storms (e.g. COVID-19-related encephalopathy), as well as between a subgroup of ICI-related neurological adverse events and paraneoplastic neurological syndromes. Therefore, these cancer immunotherapy-related neurological syndromes may provide an unprecedented, perhaps transitory, opportunity to shed light on the underlying pathogenic mechanisms of a wide spectrum of neurological syndromes and to push forward our knowledge in neuroimmunology.

Neurologic adverse events of cancer immunotherapy

Cancer immunotherapy encompasses a wide range of treatment modalities that harness the anti-tumor effects of the immune system and have revolutionized oncological treatment in recent years, with approval for its use in more and more cancers. However, it is not without side effects. Several neurological adverse events have been recognized associated with immune checkpoint inhibitors (ICI) and chimeric antigen receptor (CAR) T-cell therapy, the two main classes of cancer immunotherapy. With the increase in the prevalence of oncological diseases and this type of therapy, it is improbable that neurologists, oncologists, hematologists, and other healthcare professionals who deal with cancer patients will not encounter this type of neurologic complication in their practice in the following years. This article aims to review the epidemiology, clinical manifestations, diagnosis, and management of neurological complications associated with ICI and CAR T-cell therapy.

Neurologic Complications of Cancer Therapies

PURPOSE OF REVIEW

To review the neurologic complications of systemic anti-cancer therapies and radiation therapy.

RECENT FINDINGS

Although many of the newer systemic therapies have more favorable side effect profiles than traditional cytotoxic chemotherapy, neurotoxicity has been seen with some of newer targeted therapies, immunotherapy, and T cell engaging therapies, including CAR-T therapy. The most recent advances in radiation-induced neurotoxicity have focused on the prevention and the management of cognitive dysfunction, a known long-term complication of brain irradiation. Cancer therapies can damage both the central and the peripheral nervous systems, and the damage may not always be reversible. Neurologists and oncologists must be aware of the neurotoxicities associated with newer treatments, particularly CAR-T therapy and immunotherapy. Early recognition and appropriate management can help minimize neurologic injury.

How to diagnose and manage neurological toxicities of immune checkpoint inhibitors: an update

As the use of cancer immunotherapy with immune checkpoint inhibitors (ICIs) is expanding rapidly for the treatment of many tumor types, it is crucial that both neurologists and oncologists become familiar with the diagnosis and treatment of neurological immune-related adverse events (n-irAEs). These are rare complications, developing in their severe forms in only 1-3% of the patients, but are highly relevant due to their mortality and morbidity burden. The diagnosis of n-irAEs is-however-challenging, as many alternative diagnoses need to be considered in the complex scenario of a patient with advanced cancer developing neurological problems. A tailored diagnostic approach is advisable according to the presentation, clinical history, and known specificities of n-irAEs. Several patterns characterized by distinct clinical, immunological, and prognostic characteristics are beginning to emerge. For example, myasthenia gravis is more likely to develop after anti-programmed cell death protein 1 (PD-1) or anti-programmed cell death ligand 1 (PD-L1) treatment, while meningitis appears more frequently after anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) therapy. Also, peripheral neuropathy and Guillain-Barré syndrome seem to be more common in patients with an underlying melanoma. Central nervous system disorders (CNS) are less frequent and are more often associated with lung cancer, and some of them (especially those with limbic encephalitis and positive onconeural antibodies) have a poor prognosis. Herein, we provide an update of the recent advances in the diagnosis and treatment of neurological toxicities related to ICI use, focusing on the exclusion of alternative diagnoses, diagnostic specificities, and treatment of n-irAEs.

Central nervous system injury from novel cancer immunotherapies

PURPOSE OF REVIEW

Neurotoxicity from antineoplastic treatment remains a challenge in oncology. Cancer treatment-induced central nervous system (CNS) injury can be therapy-limiting, severely disabling, and even fatal. While emerging cancer immunotherapies have revolutionized oncology during the past decade, their immunomodulatory properties can cause immune-related adverse effects (IRAE) across organ systems, including the nervous system. Central neurologic IRAEs from chimeric antigen receptor T cells (CAR-T) and immune checkpoint inhibitors (ICPI) are challenging complications of such therapies.We aim to provide clinicians with a comprehensive review of the relevant forms of CAR-T and ICPI-associated CNS toxicity, focusing on clinical features of such complications, diagnostic workup, predictive biomarkers, and management considerations in affected patients.

RECENT FINDINGS

Unique forms of CAR-T and ICPI-related CNS toxicity have been characterized in the recent literature. CAR-T-related neurotoxicity is common and clinically well delineated. ICPI-related CNS toxicity is relatively rare but includes a heterogenous spectrum of severe and diagnostically challenging conditions. While putative risk factors, neurotoxicity biomarkers, imaging correlates and treatment strategies have been put forward, development of tailored diagnostic and management consensus guidelines awaits further clinical investigation.

SUMMARY

As CAR-T and ICPI become more widely adopted, early recognition, documentation, and management of immunotherapy-related CNS toxicity are of paramount importance in the clinical setting.

Synthesis, inverse docking-assisted identification and in vitro biological characterization of Flavonol-based analogs of fisetin as c-Kit, CDK2 and mTOR inhibitors against melanoma and non-melanoma skin cancers

Due to hurdles, including resistance, adverse effects, and poor bioavailability, among others linked with existing therapies, there is an urgent unmet need to devise new, safe, and more effective treatment modalities for skin cancers. Herein, a series of flavonol-based derivatives of fisetin, a plant-based flavonoid identified as an anti-tumorigenic agent targeting the mammalian targets of rapamycin (mTOR)-regulated pathways, were synthesized and fully characterized. New potential inhibitors of receptor tyrosine kinases (c-KITs), cyclin-dependent kinase-2 (CDK2), and mTOR, representing attractive therapeutic targets for melanoma and non-melanoma skin cancers (NMSCs) treatment, were identified using inverse-docking, in vitro kinase activity and various cell-based anticancer screening assays. Eleven compounds exhibited significant inhibitory activities greater than the parent molecule against four human skin cancer cell lines, including melanoma (A375 and SK-Mel-28) and NMSCs (A431 and UWBCC1), with IC50 values ranging from 0.12 to < 15 μM. Seven compounds were identified as potentially potent single, dual or multi-kinase c-KITs, CDK2, and mTOR kinase inhibitors after inverse-docking and screening against twelve known cancer targets, followed by kinase activity profiling. Moreover, the potent compound F20, and the multi-kinase F9 and F17 targeted compounds, markedly decreased scratch wound closure, colony formation, and heightened expression levels of key cancer-promoting pathway molecular targets c-Kit, CDK2, and mTOR. In addition, these compounds downregulated Bcl-2 levels and upregulated Bax and cleaved caspase-3/7/8 and PARP levels, thus inducing apoptosis of A375 and A431 cells in a dose-dependent manner. Overall, compounds F20, F9 and F17, were identified as promising c-Kit, CDK2 and mTOR inhibitors, worthy of further investigation as therapeutics, or as adjuvants to standard therapies for the control of melanoma and NMSCs.