C282Y-HFE gene variant affects cholesterol metabolism in human neuroblastoma cells

HFE polymorphisms affect survival of brain tumor patients

The HFE (high iron) protein plays a key role in the regulation of body iron. HFE polymorphisms (H63D and C282Y) are the common genetic variants in Caucasians. Based on frequency data, both HFE polymorphisms have been associated with increased risk in a number of cancers. The prevalence of the two major HFE polymorphisms in a human brain tumor patient populations and the impact of HFE polymorphisms on survival have not been studied. In the present study, there is no overall difference in survival by HFE genotype. However, male GBM patients with H63D HFE (H63D) have poorer overall survival than wild type HFE (WT) male GBM (p = 0.03). In GBM patients with the C282Y HFE polymorphism (C282Y), female patients have poorer survival than male patients (p = 0.05). In addition, female metastatic brain tumor patients with C282Y have shorter survival times post diagnosis than WT patients (p = 0.02) or male metastatic brain tumor patients with C282Y (p = 0.02). There is a tendency toward a lower proportion of H63D genotype in GBM patients than a non-tumor control group (p = 0.09) or other subtypes of brain tumors. In conclusion, our study suggests that HFE genotype impacts survival of brain tumor patients in a gender specific manner. We previously reported that glioma and neuroblastoma cell lines with HFE polymorphisms show greater resistance to chemo and radiotherapy. Taken together, these data suggest HFE genotype is an important consideration for evaluating and planning therapeutic strategies in brain tumor patients.

Evidence for the Influence of the Iron Regulatory MHC Class I Molecule HFE on Tumor Progression in Experimental Models and Clinical Populations

Proteins involved in iron regulation are modifiers of cancer risk and progression. Of these, the HFE protein (high iron gene and its protein product) is of particular interest because of its interaction with both iron handling and immune function and the high rate of genetic polymorphisms resulting in a mutant protein. Clinical studies suggest that HFE polymorphisms increase the risk of certain cancers, but the inconsistent outcomes suggest a more nuanced effect, possibly interacting with other genetic or environmental factors. Some basic science research has been conducted to begin to understand the implications of variant HFE genotype on cancer, but the story is far from complete. In particular, putative mechanisms exist for HFE to affect tumor progression through its role in iron handling and its major histocompatibility complex class I structural features. In this review, the current understanding of the role of HFE in cancer is described and models for future directions are identified.

HFE gene variants, iron, and lipids: a novel connection in Alzheimer's disease

Iron accumulation and associated oxidative stress in the brain have been consistently found in several neurodegenerative diseases. Multiple genetic studies have been undertaken to try to identify a cause of neurodegenerative diseases but direct connections have been rare. In the iron field, variants in the HFE gene that give rise to a protein involved in cellular iron regulation, are associated with iron accumulation in multiple organs including the brain. There is also substantial epidemiological, genetic, and molecular evidence of disruption of cholesterol homeostasis in several neurodegenerative diseases, in particular Alzheimer's disease (AD). Despite the efforts that have been made to identify factors that can trigger the pathological events associated with neurodegenerative diseases they remain mostly unknown. Because molecular phenotypes such as oxidative stress, synaptic failure, neuronal loss, and cognitive decline, characteristics associated with AD, have been shown to result from disruption of a number of pathways, one can easily argue that the phenotype seen may not arise from a linear sequence of events. Therefore, a multi-targeted approach is needed to understand a complex disorder like AD. This can be achieved only when knowledge about interactions between the different pathways and the potential influence of environmental factors on them becomes available. Toward this end, this review discusses what is known about the roles and interactions of iron and cholesterol in neurodegenerative diseases. It highlights the effects of gene variants of HFE (H63D- and C282Y-HFE) on iron and cholesterol metabolism and how they may contribute to understanding the etiology of complex neurodegenerative diseases.