Cancer control via glucose and glutamine deprivation

Wilhelm Brünings' forgotten contribution to the metabolic treatment of cancer utilizing hypoglycemia and a very low carbohydrate (ketogenic) diet

The growing interest in the alterations of tumor cell metabolism and their possible therapeutic exploitation also spurred new complementary and integrative approaches such as treating patients with a ketogenic diet (KD). KDs aim at inhibiting glycolytic tumor metabolism and growth, and have therefore been proposed as adjuncts not only to standard-of-care, but also to other therapies targeting tumor metabolism. Here I describe the life and forgotten work of one of the earliest researchers who realized the importance of altered tumor cell metabolism and its possible exploitation through metabolic modifications: Wilhelm Brünings. Brünings was a German natural scientist and physician famous for his innovative contributions to the fields of physiology and otorhinolaryngology. Based on the findings of Otto Warburg and his physiological reasoning he started to experiment with insulin administration and KDs in his patients with head and neck cancers, aiming to maximally lower blood glucose concentrations. He obtained encouraging short-term results, although most tumors became refractory to treatment after several weeks. His pioneering work is worth revisiting, especially for an international readership that may be unaware of his efforts, as hypoglycemic treatments, including the use of insulin injections and KDs, are currently being re-investigated as complementary and integrative cancer treatments.

A hypothetical method for controlling highly glycolytic cancers and metastases

Most proliferating cancer cells and cancer-associated tumor stroma have an upregulated glucose energy demand in relation to normal cells. Cancer cells are further less metabolically flexible than normal cells. They can therefore not survive metabolic stress as well as normal cells can. Metabolic deprivation thus provides a potential therapeutic window. Unfortunately, current glucose blockers have toxicity problems. An alternative way to reduce a cancer patient's blood glucose (BG), for a short-term period to very low levels, without the concomitant toxicity, is hypothesized in this paper. In vitro tests have shown that short-term BG deprivation to 2 mmol/L for 180 min is an effective cancer treatment. This level of hypoglycaemia can be maintained in vivo with a combination of very low-dose insulin and the suppression of the glucose counter-regulation system. Such suppression can be safely achieved by the infusion of somatostatin and a combination of both α and β-blockers. The proposed short-term in vivo method, was shown to be non-toxic and safe for non-cancer patients. The next step is to test the effect of the proposed method on cancer patients. It is also suggested to incorporate well-known, long-term BG deprivation treatments to achieve maximum effect.

Metabolomics-A Promising Approach to Pituitary Adenomas

Background: Metabolomics-the novel science that evaluates the multitude of low-molecular-weight metabolites in a biological system, provides new data on pathogenic mechanisms of diseases, including endocrine tumors. Although development of metabolomic profiling in pituitary disorders is at an early stage, it seems to be a promising approach in the near future in identifying specific disease biomarkers and understanding cellular signaling networks. Objectives: To review the metabolomic profile and the contributions of metabolomics in pituitary adenomas (PA). Methods: A systematic review was conducted via PubMed, Web of Science Core Collection and Scopus databases, summarizing studies that have described metabolomic aspects of PA. Results: Liquid chromatography tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR) spectrometry, which are traditional techniques employed in metabolomics, suggest amino acids metabolism appears to be primarily altered in PA. N-acetyl aspartate, choline-containing compounds and creatine appear as highly effective in differentiating PA from healthy tissue. Deoxycholic and 4-pyridoxic acids, 3-methyladipate, short chain fatty acids and glucose-6-phosphate unveil metabolite biomarkers in patients with Cushing's disease. Phosphoethanolamine, N-acetyl aspartate and myo-inositol are down regulated in prolactinoma, whereas aspartate, glutamate and glutamine are up regulated. Phosphoethanolamine, taurine, alanine, choline-containing compounds, homocysteine, and methionine were up regulated in unclassified PA across studies. Intraoperative use of ultra high mass resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), which allows localization and delineation between functional PA and healthy pituitary tissue, may contribute to achievement of complete tumor resection in addition to preservation of pituitary cell lines and vasopressin secretory cells, thus avoiding postoperative diabetes insipidus. Conclusion: Implementation of ultra high performance metabolomics analysis techniques in the study of PA will significantly improve diagnosis and, potentially, the therapeutic approach, by identifying highly specific disease biomarkers in addition to novel molecular pathogenic mechanisms. Ultra high mass resolution MALDI-MSI emerges as a helpful clinical tool in the neurosurgical treatment of pituitary tumors. Therefore, metabolomics appears to be a science with a promising prospect in the sphere of PA, and a starting point in pituitary care.