The mitochondrial ATPase inhibitory factor 1 triggers a ROS-mediated retrograde prosurvival and proliferative response.

Recent findings indicate that prevalent human carcinomas overexpress the mitochondrial ATPase Inhibitory Factor 1 (IF1). Overexpression of IF1 inhibits the synthase activity of the mitochondrial H(+)-ATP synthase and plays a crucial role in metabolic adaptation of cancer cells to enhanced aerobic glycolysis. Herein, we demonstrate that IF1 overexpression in colon cancer cells triggers mitochondrial hyperpolarization and the subsequent production of superoxide radical, a reactive oxygen species (ROS). ROS are required to promote the transcriptional activation of the NFκB pathway via phosphorylation-dependent IκBα degradation. Activation of NFκB results in a cellular adaptive response that includes proliferation and Bcl-xL mediated resistance to drug-induced cell death. Quenching the mitochondrial production of ROS prevents the activation of NFκB and abolishes the IF1-mediated cellular adaptive response. Overall, our findings provide evidence linking the activity of a mitochondrial protein with retrograde signaling to the nucleus to promote cellular proliferation and survival.

Treatment adherence to pegvisomant in patients with acromegaly in Spain: PEGASO study.

PURPOSE: The burden of chronic daily subcutaneous administration of pegvisomant on adherence has not been previously studied. This study was aimed to determine the adherence to pegvisomant treatment in acromegaly patients in the real-world clinical practice setting in Spain. METHODS: Multicenter, observational, descriptive, cross-sectional study in patients with acromegaly treated with pegvisomant for at least 12 months. Patient adherence was indirectly determined by Batalla and Haynes-Sackett questionnaires and directly by prescription record review. Additionally, treatment satisfaction was assessed by the Treatment Satisfaction with Medicines Questionnaire (SATMED-Q) and treatment convenience by an ad-hoc Pegvisomant questionnaire. Errors in reconstitution and administration process were determined by direct observation. RESULTS: 108 patients were included in the analysis. Rates of adherence varied from 60.7 to 92.1% and did not correlate with disease control. Older patient age and alternative schedules other than daily pegvisomant dosing were associated with lower adherence. Treatment satisfaction and convenience was high, with a mean (SD) total SATMED-Q score of 74.6 ± 15.4 over 100 and a total ad-hoc Pegvisomant questionnaire score of 71.2 ± 15.2 over 100. 34.3% of patients made mistakes during the reconstitution /administration process. CONCLUSIONS: Patient adherence to pegvisomant was high (60.7-92.1%), but more than a third of the patients in the study made mistakes during the administration process, with a potential impact on disease control. Besides dosing compliance, correct administration of medication should be carefully assessed in these patients.

In vivo inhibition of the mitochondrial H+-ATP synthase in neurons promotes metabolic preconditioning.

A key transducer in energy conservation and signaling cell death is the mitochondrial H(+)-ATP synthase. The expression of the ATPase inhibitory factor 1 (IF1) is a strategy used by cancer cells to inhibit the activity of the H(+)-ATP synthase to generate a ROS signal that switches on cellular programs of survival. We have generated a mouse model expressing a mutant of human IF1 in brain neurons to assess the role of the H(+)-ATP synthase in cell death in vivo. The expression of hIF1 inhibits the activity of oxidative phosphorylation and mediates the shift of neurons to an enhanced aerobic glycolysis. Metabolic reprogramming induces brain preconditioning affording protection against quinolinic acid-induced excitotoxicity. Mechanistically, preconditioning involves the activation of the Akt/p70S6K and PARP repair pathways and Bcl-xL protection from cell death. Overall, our findings provide the first in vivo evidence highlighting the H(+)-ATP synthase as a target to prevent neuronal cell death.

Preference of acromegaly patients for treatment attributes in Spain.

OBJECTIVE: Acromegaly is a rare disease caused by increased growth hormone secretion and a subsequent increase in insulin-like growth factor I (IGF-I) levels. Patients display multiple comorbidities that affect their quality of life (QoL). Treatment aims to maintain good biochemical control, tumour control and reduce the risk of comorbidities; however, their impact on QoL has been overlooked until recently. We interviewed patients to explore their preferences with regard to treatment attributes. DESIGN: A cross-sectional study based on interviews and a discrete choice experiment (DCE) in a Spanish cohort. METHODS: Adult patients diagnosed with acromegaly ≥1 year before the start of the study and under treatment were included. Treatment attributes were collected from patient testimony during face-to-face interviews. Then, a DCE was performed to elicit patient preferences for certain treatment attributes. RESULTS: Sixty-seven patients completed the study. QoL improvement was the most important treatment attribute (37%), followed by IGF-I control (20%), blood sugar control (17%) and tumour control (13%). Secondary attributes were pain associated with the route of administration (7%), diarrhoea (2%), administration method (2%) and storage conditions (2%). We then calculated the theoretical share of preference for existing treatments, based on the individual preference utility for each attribute and level. Pegvisomant obtained the highest share of preference overall, and the highest preference as a second-line treatment (53 and 95%, respectively). CONCLUSIONS: QoL greatly influences patient treatment preference. Since acromegaly patients are informed and aware of their disease, treatment choices should always be shared with patients.

Acromegaly disease activity according to ACRODAT®, a cross-sectional study in Spain: ACROVAL study.

OBJECTIVES: To evaluate disease activity status using the Acromegaly Disease Activity Tool (ACRODAT®) in a cohort of Spanish acromegaly patients, to assess the relationship between the level of disease activity according to both ACRODAT® and the physicians' clinical evaluation, and to study the potential discrepancies in the perception of symptoms between physicians and patients. DESIGN: Multicenter, observational, descriptive and cross-sectional study. METHODS: Disease activity was assessed in adult patients with acromegaly under pharmacological treatment during at least 6 months using ACRODAT®. RESULTS: According to ACRODAT®, 48.2%, 31.8% and 20.0% of a total of 111 patients were classified as having a stable disease (S), mild disease activity (M-DA) and significant disease activity (S-DA) respectively. ACRODAT® classification of disease activity significantly correlated with physicians' opinion, with a moderate inter-rater agreement and a specificity of 92.45% (PPV = 86.21%). No correlation was found between IGF-I levels and severity of symptoms or quality of life (QoL). A decision to take clinical action was significantly more frequent in S-DA and M-DA patients than S patients but no action was taken on 5 (22.7%) and 27 (77.1%) S-DA and M-DA patients, respectively CONCLUSIONS: ACRODAT® detected disease activity in 51.8% of patients. Interestingly, although M-DA and S-DA patients were likely to be in the process of being controlled, action was not always taken on these patients. ACRODAT® is a validated and highly specific tool that may be useful to routinely monitor acromegaly and to identify patients with non-obvious disease activity by incorporating "patient-centred" parameters like symptoms and QoL to the clinical evaluation of acromegaly.

Up-regulation of the ATPase inhibitory factor 1 (IF1) of the mitochondrial H+-ATP synthase in human tumors mediates the metabolic shift of cancer cells to a Warburg phenotype.

The H(+)-ATP synthase is a reversible engine of mitochondria that synthesizes or hydrolyzes ATP upon changes in cell physiology. ATP synthase dysfunction is involved in the onset and progression of diverse human pathologies. During ischemia, the ATP hydrolytic activity of the enzyme is inhibited by the ATPase inhibitory factor 1 (IF1). The expression of IF1 in human tissues and its participation in the development of human pathology are unknown. Here, we have developed monoclonal antibodies against human IF1 and determined its expression in paired normal and tumor biopsies of human carcinomas. We show that the relative mitochondrial content of IF1 increases significantly in carcinomas, suggesting the participation of IF1 in oncogenesis. The expression of IF1 varies significantly in cancer cell lines. To investigate the functional activity of IF1 in cancer, we have manipulated its cellular content. Overexpression of IF1 or of its pH-insensitive H49K mutant in cells that express low levels of IF1 triggers the up-regulation of aerobic glycolysis and the inhibition of oxidative phosphorylation with concurrent mitochondrial hyperpolarization. Treatment of the cells with the H(+)-ATP synthase inhibitor oligomycin mimicked the effects of IF1 overexpression. Conversely, small interfering RNA-mediated silencing of IF1 in cells that express high levels of IF1 promotes the down-regulation of aerobic glycolysis and the increase in oxidative phosphorylation. Overall, these findings support that the mitochondrial content of IF1 controls the activity of oxidative phosphorylation mediating the shift of cancer cells to an enhanced aerobic glycolysis, thus supporting an oncogenic role for the de-regulated expression of IF1 in cancer.

The tumor suppressor function of mitochondria: translation into the clinics.

Recently, the inevitable metabolic reprogramming experienced by cancer cells as a result of the onset of cellular proliferation has been added to the list of hallmarks of the cancer cell phenotype. Proliferation is bound to the synchronous fluctuation of cycles of an increased glycolysis concurrent with a restrained oxidative phosphorylation. Mitochondria are key players in the metabolic cycling experienced during proliferation because of their essential roles in the transduction of biological energy and in defining the life-death fate of the cell. These two activities are molecularly and functionally integrated and are both targets of commonly altered cancer genes. Moreover, energetic metabolism of the cancer cell also affords a target to develop new therapies because the activity of mitochondria has an unquestionable tumor suppressor function. In this review, we summarize most of these findings paying special attention to the opportunity that translation of energetic metabolism into the clinics could afford for the management of cancer patients. More specifically, we emphasize the role that mitochondrial beta-F1-ATPase has as a marker for the prognosis of different cancer patients as well as in predicting the tumor response to therapy.

Growth and metabolic effects of long-term recombinant human growth hormone (rhGH) treatment in short children born small for gestational age: GH-RAST study.

Objectives To study the efficacy and influence on metabolism of recombinant human growth hormone (rhGH) treatment in short children born small for gestational age (SGA). Methods Retrospective, observational, multicenter study in 305 short children born SGA, treated with rhGH during a mean ± SD of 5.03 ± 1.73 years at a mean ± SD dose of 37 ± 8 µg/kg/day. Auxological and metabolic assessment including glucose and lipids profile were collected. Results Mean ± SD age at the start of treatment was 7.11 ± 2.78 years. Height and weight improved significantly until the end of treatment from mean -2.72 (CI95%: -2.81 to -2.63) standard deviation score (SDS) to -1.16 (CI95%: -1.44 to -0.88) SDS and from -1.62 (CI95%: -1.69 to -1.55) SDS to -0.94 (CI95%: -1.14 to -0.74) SDS respectively. Mean height gain was 1.27 (CI95%: 0.99-1.54) SDS. Prepubertal patients showed higher height gain than pubertal children (mean [CI95%] = 1.44 [CI95%: 1.14-1.74] vs. 0.73 [CI95%: 0.22-1.24], p=0.02). Height gain SDS during treatment negatively correlated with chronological age (CA) and bone age (BA) delay and positively correlated with duration of treatment, height gain during first year of treatment, years on prepubertal treatment and height SDS from target height (TH). Glucose, insulin, and triglycerides increased significantly but remained within the normal range. Total and LDL-cholesterol decreased significantly, and HDL-cholesterol remained unchanged. Conclusions rhGH treatment in short SGA children effectively normalized height in most of the patients and showed a safe metabolic profile. Children who benefit the most are those with greater height SDS distance from TH, BA delay, longer duration of treatment and prepubertal treatment initiation.

Cost-effectiveness analysis of second-line pharmacological treatment of acromegaly in Spain.

Objective: To estimate the cost-effectiveness of second-line pharmacological treatments in patients with acromegaly resistant to first-generation somatostatin analogues (FG SSA) from the Spanish National Health System (NHS) perspective.Methods: A Markov model was developed to analyze the cost-effectiveness of pegvisomant and pasireotide in FG SSA-resistant acromegaly, simulating a cohort of patients from the treatment beginning to death. Treatment with pegvisomant or pasireotide was compared to FG SSA retreatment. Efficacy data were obtained from clinical trials and utilities from the literature. Direct health costs were obtained from Spanish sources (€2018).Results: The Incremental Cost Effectiveness Ratio (ICER) of pegvisomant vs. FG SSA was €85,869/Quality-adjusted life years (QALY). The ICER of pasireotide vs. FG SSA was €551,405/QALY. The ICER was mainly driven by the incremental efficacy (4.41 QALY for pegvisomant vs. FG SSA and 0.71 QALY for pasireotide vs. FG SSA), with a slightly lower increase in costs with pegvisomant (€378,597 vs. FG SSA) than with pasireotide (€393,151 vs. FG SSA).Conclusion: The ICER of pasireotide compared to FG SSA was six times higher than the ICER of pegvisomant vs. FG SSA. Pegvisomant is a more cost-effective alternative for the treatment of acromegaly in FG SSA-resistant patients in the Spanish NHS.

Burden of diabetes mellitus in patients with acromegaly treated with second-line pharmacotherapy in Spain.

OBJECTIVE: To evaluate the burden of diabetes mellitus (DM) in adult patients with acromegaly treated with second-line pharmacotherapy, from the perspective of the Spanish National Health System (NHS). METHODS: A Markov model was developed including three states: normal glucose metabolism, DM and death. The evolution of a hypothetical cohort of acromegaly patients requiring second-line pharmacological treatment (pegvisomant or pasireotide) after first generation somatostatin analogues therapy was analyzed. Direct healthcare costs regarding acromegaly management, diabetes management and drugs costs were obtained from Spanish sources. Transition probabilities between health states were obtained from published studies. Deterministic and probabilistic sensitivity analyses were undertaken. RESULTS: Compared to pasireotide, pegvisomant increased the likelihood of glucose normalization and reduced the likelihood of DM. Consequently, in a cohort of 1,000 patients with acromegaly, treatment with pegvisomant compared to pasireotide would prevent 243, 413 and 453 cases of DM after 1, 2 and 5 years, respectively, and would reduce mortality by 0.1% after 5 years of treatment. This would result in 1 million euros savings for the NHS in 5 years. These health benefits would be obtained with savings of €1,512, €3,422 and €10,162 per patient treated with pegvisomant, after 1, 2 and 5 years, respectively. After 5 years of treatment, the probability that pegvisomant generated savings versus pasireotide would be 65.3%. CONCLUSION: The favorable effects of pegvisomant on glucose metabolism would allow a considerable number of cases of DM to be avoided compared to pasireotide, resulting in savings for the NHS in Spain.

Down-regulation of oxidative phosphorylation in the liver by expression of the ATPase inhibitory factor 1 induces a tumor-promoter metabolic state.

The ATPase Inhibitory Factor 1 (IF1) is an inhibitor of the mitochondrial H+-ATP synthase that regulates the activity of both oxidative phosphorylation (OXPHOS) and cell death. Here, we have developed transgenic Tet-On and Tet-Off mice that express a mutant active form of hIF1 in the hepatocytes to restrain OXPHOS in the liver to investigate the relevance of mitochondrial activity in hepatocarcinogenesis. The expression of hIF1 promotes the inhibition of OXPHOS in both Tet-On and Tet-Off mouse models and induces a state of metabolic preconditioning guided by the activation of the stress kinases AMPK and p38 MAPK. Expression of the transgene significantly augmented proliferation and apoptotic resistance of carcinoma cells, which contributed to an enhanced diethylnitrosamine-induced liver carcinogenesis. Moreover, the expression of hIF1 also diminished acetaminophen-induced apoptosis, which is unrelated to differences in permeability transition pore opening. Mechanistically, cell survival in hIF1-preconditioned hepatocytes results from a nuclear factor-erythroid 2-related factor (Nrf2)-guided antioxidant response. The results emphasize in vivo that a metabolic phenotype with a restrained OXPHOS in the liver is prone to the development of cancer.

Glucose avidity of carcinomas.

The cancer cell phenotype has been summarized in six hallmarks [D. Hanahan, R.A. Weinberg, The hallmarks of cancer, Cell 100 (1) (2000) 57-70]. Following the conceptual trait established in that review towards the comprehension of cancer, herein we summarize the basis of an underlying principle that is fulfilled by cancer cells and tumors: its avidity for glucose. Our purpose is to push forward that the metabolic reprogramming that operates in the cancer cell represents a seventh hallmark of the phenotype that offers a vast array of possibilities for the future treatment of the disease. We summarize the metabolic pathways that extract matter and energy from glucose, paying special attention to the concerted regulation of these pathways by the ATP mass-action ratio. The molecular and functional evidences that support the high glucose uptake and the "abnormal" aerobic glycolysis of the carcinomas are detailed discussing also the role that some oncogenes and tumor suppressors have in these pathways. We overview past and present evidences that sustain that mitochondria of the cancer cell are impaired, supporting the original Warburg's formulation that ascribed the high glucose uptake of cancer cells to a defective mitochondria. A simple proteomic approach designed to assess the metabolic phenotype of cancer, i.e., its bioenergetic signature, molecularly and functionally supports Warburg's hypothesis. Furthermore, we discuss the clinical utility that the bioenergetic signature might provide. Glycolysis is presented as the "selfish" pathway used for cellular proliferation, providing both the metabolic precursors and the energy required for biosynthetic purposes, in the context of a plethora of substrates. The glucose avidity of carcinomas is thus presented as the result of both the installment of glycolysis for cellular proliferation and of the impairment of mitochondrial activity in the cancer cell. At the end, the repression of mitochondrial activity affords the cancer cell with a cell-death resistant phenotype making them prone to malignant growth.