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Del Barco S.,Catalan Institute of Nanoscience and Nanotechnology | Del Barco S.,Girona Biomedical Research Institute | Vazquez-Martin A.,Girona Biomedical Research Institute | Vazquez-Martin A.,Catalan Institute of Nanoscience and Nanotechnology | And 11 more authors.
Oncotarget | Year: 2011

The biguanide metformin, a widely used drug for the treatment of type 2 diabetes, may exert cancer chemopreventive effects by suppressing the transformative and hyperproliferative processes that initiate carcinogenesis. Metformin's molecular targets in cancer cells (e.g., mTOR, HER2) are similar to those currently being used for directed cancer therapy. However, metformin is nontoxic and might be extremely useful for enhancing treatment efficacy of mechanism-based and biologically targeted drugs. Here, we first revisit the epidemiological, preclinical, and clinical evidence from the last 5 years showing that metformin is a promising candidate for oncology therapeutics. Second, the anticancer effects of metformin by both direct (insulin-independent) and indirect (insulin-dependent) mechanisms are discussed in terms of metformin-targeted processes and the ontogenesis of cancer stem cells (CSC), including Epithelial-to-Mesenchymal Transition (EMT) and microRNAs-regulated dedifferentiation of CSCs. Finally, we present preliminary evidence that metformin may regulate cellular senescence, an innate safeguard against cellular immortalization. There are two main lines of evidence that suggest that metformin's primary target is the immortalizing step during tumorigenesis. First, metformin activates intracellular DNA damage response checkpoints. Second, metformin attenuates the anti-senescence effects of the ATP-generating glycolytic metabotype-the Warburg effect-, which is required for self-renewal and proliferation of CSCs. If metformin therapy presents an intrinsic barrier against tumorigenesis by lowering the threshold for stress-induced senescence, metformin therapeutic strategies may be pivotal for therapeutic intervention for cancer. Current and future clinical trials will elucidate whether metformin has the potential to be used in preventive and treatment settings as an adjuvant to current cancer therapeutics. © Barco et al.


Menendez J.A.,Catalan Institute of Nanoscience and Nanotechnology | Menendez J.A.,Girona Biomedical Research Institute
Cell Cycle | Year: 2015

The Nobel prized discovery of nuclear reprogramming is swiftly providing mechanistic evidence of a role for metabolism in the generation of cancer stem cells (CSC). Traditionally, the metabolic demands of tumors have been viewed as drivers of the genetic programming detected in cancer tissues. Beyond the energetic requirements of specific cancer cell states, it is increasingly recognized that metabolism per se controls epi-transcriptional networks to dictate cancer cell fate, i.e., metabolism can define CSC. Here I review the CSC-related metabolic features found in induced pluripotent stem (iPS) cells to provide an easily understandable framework in which the infrastructure and functioning of cellular metabolism might control the efficiency and kinetics of reprogramming in the rerouting of non-CSC to CSC-like cellular states. I suggest exploring how metabolism-dependent regulation of epigenetics can play a role in directing CSC states beyond conventional energetic demands of stage-specific cancer cell states, opening a new dimension of cancer in which the “physiological state” of CSC might be governed not only by cell-autonomous cues but also by local micro-environmental and systemic metabolo-epigenetic interactions. Forthcoming studies should decipher how specific metabolites integrate and mediate the overlap between the CSC-intrinsic “micro-epigenetics” and the “upstream” local and systemic “macro-epigenetics,” thus paving the way for targeted epigenetic regulation of CSCs through metabolic modulation including “smart foods” or systemic “metabolic nichotherapies.” © 2015 Taylor and Francis Group, LLC.


Corominas-Faja B.,Catalan Institute of Nanoscience and Nanotechnology | Corominas-Faja B.,Girona Biomedical Research Institute | Quirantes-Pine R.,University of Granada | Oliveras-Ferraros C.,Catalan Institute of Nanoscience and Nanotechnology | And 12 more authors.
Aging | Year: 2012

Metabolomic fingerprint of breast cancer cells treated with the antidiabetic drug metformin revealed a significant accumulation of 5-formimino-tetrahydrofolate, one of the tetrahydrofolate forms carrying activated one-carbon units that are essential for the de novo synthesis of purines and pyrimidines. De novo synthesis of glutathione, a folate-dependent pathway interconnected with one-carbon metabolism was concomitantly depleted in response to metformin. End-product reversal studies demonstrated that thymidine alone leads to a significant but incomplete protection from metformin's cytostatic effects. The addition of the substrate hypoxanthine for the purine salvage pathway produces major rightward shifts in metformin's growth inhibition curves. Metformin treatment failed to activate the DNA repair protein ATM kinase and the metabolic tumor suppressor AMPK when thymidine and hypoxanthine were present in the extracellular milieu. Our current findings suggest for the first time that metformin can function as an antifolate chemotherapeutic agent that induces the ATM/AMPK tumor suppressor axis secondarily following the alteration of the carbon flow through the folate-related onecarbon metabolic pathways. © Corominas-Faja et al.


Menendez J.A.,Catalan Institute of Nanoscience and Nanotechnology | Menendez J.A.,Girona Biomedical Research Institute | Vellon L.,Cell Reprogramming Unit | Oliveras-Ferraros C.,Catalan Institute of Nanoscience and Nanotechnology | And 5 more authors.
Cell Cycle | Year: 2011

Molecular controllers of the number and function of tissue stem cells may share common regulatory pathways for the nuclear reprogramming of somatic cells to become induced pluripotent stem cells (iPSCs). If this hypothesis is true, testing the ability of longevity-promoting chemicals to improve reprogramming efficiency may provide a proof-of-concept validation tool for pivotal housekeeping pathways that limit the numerical and/or functional decline of adult stem cells. Reprogramming is a slow, stochastic process due to the complex and apparently unrelated cellular processes that are involved. First, forced expression of the Yamanaka cocktail of stemness factors, OSKM, is a stressful process that activates apoptosis and cellular senescence, which are the two primary barriers to cancer development and somatic reprogramming. Second, the a priori energetic infrastructure of somatic cells appears to be a crucial stochastic feature for optimal successful routing to pluripotency. If longevity-promoting compounds can ablate the drivers and effectors of cellular senescence while concurrently enhancing a bioenergetic shift from somatic oxidative mitochondria toward an alternative ATP-generating glycolytic metabotype, they could maximize the efficiency of somatic reprogramming to pluripotency. Support for this hypothesis is evidenced by recent findings that well-characterized mTOR inhibitors and autophagy activators (e.g., PP242, rapamycin and resveratrol) notably improve the speed and efficiency of iPSC generation. This article reviews the existing research evidence that the most established mTOR inhibitors can notably decelerate the cellular senescence that is imposed by DNA damage-like responses, which are somewhat equivalent to the responses caused by reprogramming factors. These data suggest that fine-tuning mTOR signaling can impact mitochondrial dynamics to segregate mitochondria that are destined for clearance through autophagy, which results in the loss of mitochondrial function and in the accelerated onset of the glycolytic metabolism that is required to fuel reprogramming. By critically exploring how mTOR-regulated senescence, bioenergetic infrastructure and autophagy can actively drive the reprogramming of somatic cells to pluripotency, we define a metabolic roadmap that may be helpful for designing pharmacological and behavioral interventions to prevent or retard the dysfunction/exhaustion of aging stem cell populations. © 2011 Landes Bioscience.


Menendez J.A.,Catalan Institute of Nanoscience and Nanotechnology | Menendez J.A.,Girona Biomedical Research Institute | Oliveras-Ferraros C.,Catalan Institute of Nanoscience and Nanotechnology | Oliveras-Ferraros C.,Girona Biomedical Research Institute | And 9 more authors.
Cell Cycle | Year: 2012

Glucose deprivation is a distinctive feature of the tumor microecosystem caused by the imbalance between poor supply and an extraordinarily high consumption rate. The metabolic reprogramming from mitochondrial respiration to aerobic glycolysis in cancer cells (the "Warburg effect") is linked to oncogenic transformation in a manner that frequently implies the inactivation of metabolic checkpoints such as the energy rheostat AMP-activated protein kinase (AMPK). Because the concept of synthetic lethality in oncology can be applied not only to genetic and epigenetic intrinsic differences between normal and cancer cells but also to extrinsic ones such as altered microenvironment, we recently hypothesized that stress-energy mimickers such as the AMPK agonist metformin should produce metabolic synthetic lethality in a glucose-starved cell culture milieu imitating the adverse tumor growth conditions in vivo. Under standard high-glucose conditions, metformin supplementation mostly caused cell cycle arrest without signs of apoptotic cell death. Under glucose withdrawal stress, metformin supplementation circumvented the ability of oncogenes (e.g., HER2) to protect breast cancer cells from glucose-deprivation apoptosis. Significantly, representative cell models of breast cancer heterogeneity underwent massive apoptosis (by > 90% in some cases) when glucose-starved cell cultures were supplemented with metformin. Our current findings may uncover crucial issues regarding the cell-autonomous metformin's anticancer actions: (1) The offently claimed clinically irrelevant, non-physiological concentrations needed to observe the metformin's anticancer effects in vitro merely underlie the artifactual interference of erroneous glucoserich experimental conditions that poorly reflect glucose-starved in vivo conditions; (2) the preferential killing of cancer stem cells (CSC) by metformin may simply expose the best-case scenario for its synthetically lethal activity because an increased dependency on Warburglike aerobic glycolysis (hyperglycolytic phenotype) is critical to sustain CSC stemness and immortality; (3) the microenvironment-mediated contextual synthetic lethality of metformin should be expected to enormously potentiate the anticancer effect of anti-angiogenesis agents that promote severe oxygen and glucose deprivation in certain areas of the tumor tissues. © 2012 Landes Bioscience.


Menendez J.A.,Catalan Institute of Nanoscience and Nanotechnology | Menendez J.A.,Girona Biomedical Research Institute | Cufi S.,Catalan Institute of Nanoscience and Nanotechnology | Cufi S.,Girona Biomedical Research Institute | And 7 more authors.
Aging | Year: 2011

By activating the ataxia telangiectasia mutated (ATM)-mediated DNA Damage Response (DDR), the AMPK agonist metformin might sensitize cells against further damage, thus mimicking the precancerous stimulus that induces an intrinsic barrier against carcinogenesis. Herein, we present the new hypothesis that metformin might function as a tissue sweeper of pre-malignant cells before they gain stem cell/tumor initiating properties. Because enhanced glycolysis (the Warburg effect) plays a causal role in the gain of stem-like properties of tumor-initiating cells by protecting them from the pro-senescent effects of mitochondrial respiration-induced oxidative stress, metformin's ability to disrupt the glycolytic metabotype may generate a cellular phenotype that is metabolically protected against immortalization. The bioenergetic crisis imposed by metformin, which may involve enhanced mitochondrial biogenesis and oxidative stress, can lower the threshold for cellular senescence by pre-activating an ATM-dependent pseudo-DDR. This allows an accelerated onset of cellular senescence in response to additional oncogenic stresses. By pushing cancer cells to use oxidative phosphorylation instead of glycolysis, metformin can rescue cell surface major histocompatibility complex class I (MHC-I) expression that is downregulated by oncogenic transformation, a crucial adaptation of tumor cells to avoid the adaptive immune response by cytotoxic T-lymphocytes (CTLs). Aside from restoration of tumor immunosurveillance at the cell-autonomous level, metformin can activate a senescence-associated secretory phenotype (SASP) to reinforce senescence growth arrest, which might trigger an immune-mediated clearance of the senescent cells in a non-cell-autonomous manner. By diminishing the probability of escape from the senescence anti-tumor barrier, the net effect of metformin should be a significant decrease in the accumulation of dysfunctional, pre-malignant cells in tissues, including those with the ability to initiate tumors. As life-long or late-life removal of senescent cells has been shown to prevent or delay the onset or progression of age-related disorders, the tissue sweeper function of metformin may inhibit the malignant/metastatic progression of premalignant/senescent tumor cells and increase the human lifespan. © Menendez et al.


PubMed | University of Granada, Azienda Unita Sanitaria Locale and IRCCS, CIBER ISCIII, Girona Biomedical Research Institute and 4 more.
Type: | Journal: Tumori | Year: 2016

Rare cancers represent 22% of all tumors in Europe; however, the quality of the data of rare cancers may not be as good as the quality of data for common cancer. The project surveillance of rare cancers in Europe (RARECARE) had, among others, the objective of assessing rare cancer data quality in population-based cancer registries (CRs). Eight rare cancers were considered: mesothelioma, liver angiosarcoma, sarcomas, tumors of oral cavity, CNS tumors, germ cell tumors, leukemia, and malignant digestive endocrine tumors.We selected data on 18,000 diagnoses and revised, on the basis of the pathologic and clinical reports (but not on pathologic specimens), unspecified morphology and topography codes originally attributed by CR officers and checked the quality of follow-up of long-term survivors of poor prognosis cancers.A total of 38 CRs contributed from 13 European countries. The majority of unspecified morphology and topography cases were confirmed as unspecified. The few unspecified cases that, after the review, changed to a more specific diagnosis increased the incidence of the common cancer histotypes. For example, 11% of the oral cavity epithelial cancers were reclassified from unspecified to more specific diagnoses: 8% were reclassified as squamous cell carcinoma (commoner) and only 1% as adenocarcinoma (rarer). The revision confirmed the majority of long-term survivors revealing a relative high proportion of mesothelioma long-term survivors. The majority of appendix carcinoids changed behavior from malignant to borderline lesions.Our study suggests that the problem of poorly specified morphology and topography cases is mainly one of difficulty in reaching a precise diagnosis. The awareness of the importance of data quality for rare cancers should increase among registrars, pathologists, and clinicians.


PubMed | St Jude Childrens Research Hospital, Stanford University, Girona Biomedical Research Institute, London School of Hygiene and Tropical Medicine and Cancer Prevention Institute of California
Type: Journal Article | Journal: British journal of haematology | Year: 2016

A better understanding of factors associated with early death and survival among children, adolescents and young adults with acute myeloid leukaemia (AML) may guide health policy aimed at improving outcomes in these patients. We examined trends in early death and survival among 3935 patients aged 0-39years with de novo AML in California during 1988-2011 and investigated the associations between sociodemographic and selected clinical factors and outcomes. Early death declined from 97% in 1988-1995 to 71% in 2004-2011 (P=0062), and survival improved substantially over time. However, 5-year survival was still only 50% (95% confidence interval 47-53%) even in the most recent treatment period (2004-2011). Overall, the main factors associated with poor outcomes were older age at diagnosis, treatment at hospitals not affiliated with National Cancer Institute-designated cancer centres, and black race/ethnicity. For patients diagnosed during 1996-2011, survival was lower among those who lacked health insurance compared to those with public or private insurance. We conclude that mortality after AML remained strikingly high in California and increased with age. Possible strategies to improve outcomes include wider insurance coverage and treatment at specialized cancer centres.

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