Metabolic activation triggered by cAMP in MCF-7 cells generates lethal vulnerability to combined oxamate/etomoxir.

BACKGROUND: Altered energy metabolism is a biochemical fingerprint of cancer cells, widely recognized as one of the "hallmarks of cancer". Cancer cells show highly increased rates of glucose uptake and glycolysis, after which the resulting pyruvate is converted to lactate. The maintenance of this metabolic asset is warranted by lactate dehydrogenase A (LDH-A) and for this reason the development of novel LDH-targeted anticancer therapeutics is underway. However, possible interference in cancer cell metabolism could also arise from cAMP signaling pathway, which could be activated by either oncogenic induction or exogenously, as a result of microenvironment-derived stimuli, increasing cellular cAMP levels. This study aimed at evaluating the impact of activated cAMP signaling pathway on the efficacy of an LDH-targeted anticancer approach. METHODS: We exogenously activated cAMP signaling in MCF-7 human breast cancer cells and explored the metabolic interplay between LDH-A and cAMP pathway. RESULTS: In cAMP-activated cells, we evidenced changes in energy metabolism which reduced their response to LDH inhibition. Interestingly, these experiments also highlighted a potential vulnerability state of treated cells. CONCLUSIONS: cAMP-induced metabolic changes made MCF-7 cells a preferential target of a drug combination treatment which should not affect normal cell viability. GENERAL SIGNIFICANCE: cAMP is a well-recognized second messenger of the pro-inflammatory cascade. The obtained results are relevant in consideration of the crucial role played by inflammation in normal breast cell transformation and in cancer progression. Furthermore, they corroborate the idea of exploiting the metabolic changes observed in cancer cells to obtain a therapeutic advantage.

Dietary geraniol ameliorates intestinal dysbiosis and relieves symptoms in irritable bowel syndrome patients: a pilot study.

BACKGROUND: (Trans)-3,7-Dimethyl-2,6-octadien-1-ol, commonly called geraniol (Ge-OH), is an acyclic monoterpene alcohol with well-known anti-inflammatory and antimicrobial properties. Ge-OH is a non-toxic compound classified as Generally Recognized As Safe (GRAS) by the US Food and Drug Administration and the European Food Security Agency. METHODS: Ge-OH was orally administered at a maximum daily dose of 8 mg kg(- 1) body weight for four weeks in a delayed release formulation capable of reaching the colon. Fecal microbiota and blood cytokines were analyzed before and after Ge-OH treatment, as well as IBS symptomatology by using Visual Analogue Scale (VAS-IBS). RESULTS: The results show that orally administered Ge-OH is a powerful modulator of the intestinal microbial ecosystem, capable of leading to increased relative abundances of Collinsella and especially Faecalibacterium, a well-known health-promoting butyrate producer consistently found to be decreased in IBS patients. Moreover, Ge-OH strongly improved the clinical symptoms of colitis by significantly reducing the score recorded by the VAS-IBS questionnaire. Clinical improvement was associated with a significant reduction in the circulating MIP-1ß, a chemokine found to be increased in several IBS patients. CONCLUSION: Ge-OH could be a powerful component for food supplement targeted to the treatment of IBS patients. TRIAL REGISTRATION: ISRCTN47041881 , retrospectively registered on 19th July 2018.

The activation of lactate dehydrogenase induced by mTOR drives neoplastic change in breast epithelial cells.

mTOR kinase and the A isoform of lactate dehydrogenase (LDH-A) are key players controlling the metabolic characteristics of cancer cells. By using cultured human breast cells as a "metabolic tumor" model, we attempted to explore the correlation between these two factors. "Metabolic tumors" are defined as neoplastic conditions frequently associated with features of the metabolic syndrome, such as hyper-insulinemia and hyper-glycemia. MCF-7 cells (a well differentiated carcinoma) and MCF-10A cells (a widely used model for studying normal breast cell transformation) were used in this study. These cells were exposed to known factors triggering mTOR activation. In both treated cultures, we evaluated the link between mTOR kinase activity and the level of LDH expression / function. Furthermore, we elaborated the metabolic changes produced in cells by the mTOR-directed LDH-A up-regulation. Interestingly, we observed that in the non-neoplastic MCF-10A culture, mTOR-directed up-regulation of LDH-A was followed by a reprogramming of cell metabolism, which showed an increased dependence on glycolysis rather than on oxidative reactions. As a consequence, lactate production appeared to be enhanced and cells began to display increased self-renewal and clonogenic power: signals suggestive of neoplastic change. Enhanced clonogenicity of cells was abolished by rapamycin treatment, and furthermore heavily reduced by LDH enzymatic inhibition. These results highlighted a mechanistic link between metabolic alterations and tumorigenesis, whereby suggesting LDH inhibition as a possible chemo-preventive measure to target the metabolic alterations driving neoplastic change.

Geraniol Pharmacokinetics, Bioavailability and Its Multiple Effects on the Liver Antioxidant and Xenobiotic-Metabolizing Enzymes.

Geraniol is a natural monoterpene showing anti-inflammatory, antioxidant, neuroprotective and anticancer effects. No pharmacokinetic and bioavailability data on geraniol are currently available. We therefore performed a systematic study to identify the permeation properties of geraniol across intestinal cells, and its pharmacokinetics and bioavailability after intravenous and oral administration to rats. In addition, we systematically investigated the potential hepatotoxic effects of high doses of geraniol on hepatic phase I, phase II and antioxidant enzymatic activities and undertook a hematochemical analysis on mice. Permeation studies performed via HPLC evidenced geraniol permeability coefficients across an in vitro model of the human intestinal wall for apical to basolateral and basolateral to apical transport of 13.10 ± 2.3 × 10-3 and 2.1 ± 0.1â‹…× 10-3 cm/min, respectively. After intravenous administration of geraniol to rats (50 mg/kg), its concentration in whole blood (detected via HPLC) decreased following an apparent pseudo-first order kinetics with a half-life of 12.5 ± 1.5 min. The absolute bioavailability values of oral formulations (50 mg/kg) of emulsified geraniol or fiber-adsorbed geraniol were 92 and 16%, respectively. Following emulsified oral administration, geraniol amounts in the cerebrospinal fluid of rats ranged between 0.72 ± 0.08 µg/mL and 2.6 ± 0.2 µg/mL within 60 min. Mice treated with 120 mg/kg of geraniol for 4 weeks showed increased anti-oxidative defenses with no signs of liver toxicity. CYP450 enzyme activities appeared only slightly affected by the high dosage of geraniol.