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Pharmaceutics Mar 2020Phenformin and metformin are antihyperglycemic drugs that belong to the class of biguanides. Previously, we demonstrated that metformin elicits renoprotective effects in...
Phenformin and metformin are antihyperglycemic drugs that belong to the class of biguanides. Previously, we demonstrated that metformin elicits renoprotective effects in unilateral ureteral obstructed mice by reducing the infiltration of immune cells into the kidney. Since phenformin is a more potent drug as compared to metformin, we investigated the renoprotective properties of phenformin. We studied the efficacy of both drugs using mice that underwent unilateral ureteral obstruction. Renal damage was evaluated on RNA and protein level by qPCR, Western blotting, and immunohistochemistry. Moreover, we studied immune cell infiltration using flow cytometry. Both biguanides significantly reduced UUO-induced kidney injury, as illustrated by a reduction in KIM-1 protein expression. In addition, both metformin and phenformin impacted the gene expression of several inflammatory markers but to a different extent. Moreover, in contrast to metformin, phenformin did not impact immune cell infiltration into UUO kidneys. In conclusion, we demonstrated that phenformin has similar renoprotective effects as metformin, but the mechanism of action differs, and phenformin is more potent. The beneficial effects of phenformin are probably due to inhibition of the STAT3 pathway and mitochondrial complex I. Further research is needed to unveil the therapeutic potential of phenformin for the treatment of renal injury, either at low, non-toxic concentrations or as part of a combination therapy.
PubMed: 32224876
DOI: 10.3390/pharmaceutics12040301 -
Open Biology Jul 2019The AMP-activated protein kinase (AMPK) acts as a cellular energy sensor. Once switched on by increases in cellular AMP : ATP ratios, it acts to restore energy... (Review)
Review
The AMP-activated protein kinase (AMPK) acts as a cellular energy sensor. Once switched on by increases in cellular AMP : ATP ratios, it acts to restore energy homeostasis by switching on catabolic pathways while switching off cell growth and proliferation. The canonical AMP-dependent mechanism of activation requires the upstream kinase LKB1, which was identified genetically to be a tumour suppressor. AMPK can also be switched on by increases in intracellular Ca, by glucose starvation and by DNA damage via non-canonical, AMP-independent pathways. Genetic studies of the role of AMPK in mouse cancer suggest that, before disease arises, AMPK acts as a tumour suppressor that protects against cancer, with this protection being further enhanced by AMPK activators such as the biguanide phenformin. However, once cancer has occurred, AMPK switches to being a tumour promoter instead, enhancing cancer cell survival by protecting against metabolic, oxidative and genotoxic stresses. Studies of genetic changes in human cancer also suggest diverging roles for genes encoding subunit isoforms, with some being frequently amplified, while others are mutated.
Topics: AMP-Activated Protein Kinases; Animals; Energy Metabolism; Genes, Tumor Suppressor; Glucose; Humans; Mice; Neoplasms; Protein Kinase Inhibitors; Signal Transduction
PubMed: 31288625
DOI: 10.1098/rsob.190099 -
Biometals : An International Journal on... Aug 2019Excessive activities of cysteinyl cathepsins (CysCts) contribute to the progress of many diseases; however, therapeutic inhibition has been problematic. Zn is a natural... (Review)
Review
Excessive activities of cysteinyl cathepsins (CysCts) contribute to the progress of many diseases; however, therapeutic inhibition has been problematic. Zn is a natural inhibitor of proteases with CysHis dyads or CysHis(Xaa) triads. Biguanide forms bidentate metal complexes through the two imino nitrogens. Here, it is discussed that phenformin (phenylethyl biguanide) is a model for recruitment of endogenous Zn to inhibit CysHis/CysHis(X) peptidolysis. Phenformin is a Zn-interactive, anti-proteolytic agent in bioassay of living tissue. Benzoyl-L-arginine amide (BAA) is a classical substrate of papain-like proteases; the amide bond is scissile. In this review, the structures of BAA and the phenformin-Zn complex were compared in silico. Their chemistry and dimensions are discussed in light of the active sites of papain-like proteases. The phenyl moieties of both structures bind to the "S2" substrate-binding site that is typical of many proteases. When the phenyl moiety of BAA binds to S2, then the scissile amide bond is directed to the position of the thiolate-imidazolium ion pair, and is then hydrolyzed. However, when the phenyl moiety of phenformin binds to S2, then the coordinated Zn is directed to the identical position; and catalysis is inhibited. Phenformin stabilizes a "Zn sandwich" between the drug and protease active site. Hundreds of biguanide derivatives have been synthesized at the 1 and 5 nitrogen positions; many more are conceivable. Various substituent moieties can register with various arrays of substrate-binding sites so as to align coordinated Zn with catalytic partners of diverse proteases. Biguanide is identified here as a modifiable pharmacophore for synthesis of therapeutic CysCt inhibitors with a wide range of potencies and specificities. Phenformin-Zn Complex.
Topics: Biguanides; Biological Assay; Cathepsins; Phenformin; Zinc
PubMed: 31044334
DOI: 10.1007/s10534-019-00197-1 -
Biomolecules Oct 2020Damage to cerebral mitochondria, particularly opening of mitochondrial permeability transition pore (MPTP), is a key mechanism of ischemic brain injury, therefore,...
Damage to cerebral mitochondria, particularly opening of mitochondrial permeability transition pore (MPTP), is a key mechanism of ischemic brain injury, therefore, modulation of MPTP may be a potential target for a neuroprotective strategy in ischemic brain pathologies. The aim of this study was to investigate whether biguanides-metformin and phenformin as well as other inhibitors of Complex I of the mitochondrial electron transfer system may protect against ischemia-induced cell death in brain slice cultures by suppressing MPTP, and whether the effects of these inhibitors depend on the age of animals. Experiments were performed on brain slice cultures prepared from 5-7-day (premature) and 2-3-month old (adult) rat brains. In premature brain slice cultures, simulated ischemia (hypoxia plus deoxyglucose) induced necrosis whereas in adult rat brain slice cultures necrosis was induced by hypoxia alone and was suppressed by deoxyglucose. Phenformin prevented necrosis induced by simulated ischemia in premature and hypoxia-induced-in adult brain slices, whereas metformin was protective in adult brain slices cultures. In premature brain slices, necrosis was also prevented by Complex I inhibitors rotenone and amobarbital and by MPTP inhibitor cyclosporine A. The latter two inhibitors were protective in adult brain slices as well. Short-term exposure of cultured neurons to phenformin, metformin and rotenone prevented ionomycin-induced MPTP opening in intact cells. The data suggest that, depending on the age, phenformin and metformin may protect the brain against ischemic damage possibly by suppressing MPTP via inhibition of mitochondrial Complex I.
Topics: Animals; Brain; Brain Injuries; Electron Transport Complex I; Humans; Male; Metformin; Mitochondria; Mitochondrial Permeability Transition Pore; Mitochondrial Transmembrane Permeability-Driven Necrosis; Necrosis; Neurons; Neuroprotective Agents; Oxidative Phosphorylation; Phenformin; Rats
PubMed: 33019635
DOI: 10.3390/biom10101400 -
Proceedings of the National Academy of... Jun 2021Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that typically causes asymptomatic infection but can promote B lymphoid tumors in the immune suppressed. In vitro,...
Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that typically causes asymptomatic infection but can promote B lymphoid tumors in the immune suppressed. In vitro, EBV infection of primary B cells stimulates glycolysis during immortalization into lymphoblastoid cell lines (LCLs). Lactate export during glycolysis is crucial for continued proliferation of many cancer cells-part of a phenomenon known as the "Warburg effect"- and is mediated by monocarboxylate transporters (MCTs). However, the role of MCTs has yet to be studied in EBV-associated malignancies, which display Warburg-like metabolism in vitro. Here, we show that EBV infection of B lymphocytes directly promotes temporal induction of MCT1 and MCT4 through the viral proteins EBNA2 and LMP1, respectively. Functionally, MCT1 was required for early B cell proliferation, and MCT4 up-regulation promoted acquired resistance to MCT1 antagonism in LCLs. However, dual MCT1/4 inhibition led to LCL growth arrest and lactate buildup. Metabolic profiling in LCLs revealed significantly reduced oxygen consumption rates (OCRs) and NAD+/NADH ratios, contrary to previous observations of increased OCR and unaltered NAD+/NADH ratios in MCT1/4-inhibited cancer cells. Furthermore, U-C-glucose labeling of MCT1/4-inhibited LCLs revealed depleted glutathione pools that correlated with elevated reactive oxygen species. Finally, we found that dual MCT1/4 inhibition also sensitized LCLs to killing by the electron transport chain complex I inhibitors phenformin and metformin. These findings were extended to viral lymphomas associated with EBV and the related gammaherpesvirus KSHV, pointing at a therapeutic approach for targeting both viral lymphomas.
Topics: B-Lymphocytes; Cell Line, Tumor; Cell Proliferation; Epstein-Barr Virus Infections; Glucose; Glutathione; Herpesvirus 4, Human; Herpesvirus 8, Human; Humans; Lactic Acid; Lymphoma; Metformin; Monocarboxylic Acid Transporters; NAD; Oxygen Consumption; Phenformin; Reactive Oxygen Species; Up-Regulation
PubMed: 34161263
DOI: 10.1073/pnas.2022495118 -
The FEBS Journal Oct 2021Many metabolic phenotypes in cancer cells are also characteristic of proliferating nontransformed mammalian cells, and attempts to distinguish between phenotypes...
Many metabolic phenotypes in cancer cells are also characteristic of proliferating nontransformed mammalian cells, and attempts to distinguish between phenotypes resulting from oncogenic perturbation from those associated with increased proliferation are limited. Here, we examined the extent to which metabolic changes corresponding to oncogenic KRAS expression differed from those corresponding to epidermal growth factor (EGF)-driven proliferation in human mammary epithelial cells (HMECs). Removal of EGF from culture medium reduced growth rates and glucose/glutamine consumption in control HMECs despite limited changes in respiration and fatty acid synthesis, while the relative contribution of branched-chain amino acids to the TCA cycle and lipogenesis increased in the near-quiescent conditions. Most metabolic phenotypes measured in HMECs expressing mutant KRAS were similar to those observed in EGF-stimulated control HMECs that were growing at comparable rates. However, glucose and glutamine consumption as well as lactate and glutamate production were lower in KRAS-expressing cells cultured in media without added EGF, and these changes correlated with reduced sensitivity to GLUT1 inhibitor and phenformin treatment. Our results demonstrate the strong dependence of metabolic behavior on growth rate and provide a model to distinguish the metabolic influences of oncogenic mutations and nononcogenic growth.
Topics: Animals; Breast; Breast Neoplasms; Carcinogenesis; Cell Proliferation; Epidermal Growth Factor; Epithelial Cells; Female; Gene Expression Regulation, Neoplastic; Glucose; Glucose Transporter Type 1; Glutamic Acid; Glutamine; Humans; Lactic Acid; Mammary Glands, Human; Proto-Oncogene Proteins p21(ras); Tumor Cells, Cultured
PubMed: 33811729
DOI: 10.1111/febs.15858 -
Scientific Reports Nov 2022Lung adenocarcinoma (LUAD) is one of the most universal types of cancer all over the world and its morbidity continues to rise year by year. Growing evidence has...
Lung adenocarcinoma (LUAD) is one of the most universal types of cancer all over the world and its morbidity continues to rise year by year. Growing evidence has demonstrated that endoplasmic reticulum stress is highly activated in cancer cells and plays a key role in regulating the fate of cancer cells. However, the role and mechanism of endoplasmic reticulum stress in lung adenocarcinoma genesis and development remains unclear. In this research, we developed a prognostic model to predict the overall survival of patients with LUAD utilizing endoplasmic reticulum stress-related genes and screened out potential small molecular compounds, which could assist the clinician in making accurate decisions and better treat LUAD patients. Firstly, we downloaded 419 endoplasmic reticulum stress-related genes (ERSRGs) from Molecular Signatures Database (MSigDB). Secondly, we obtained information about the transcriptome profiling and corresponding clinical data of 59 normal samples and 535 lung adenocarcinoma samples from The Cancer Genome Atlas (TCGA) database. Next, we used the DESeq2 package to identify differentially expressed genes related to endoplasmic reticulum stress. We performed univariate Cox, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analysis to establish a prognostic model for LUAD patients based on ERSRGs. Then, we carried out univariate and multivariate independent prognostic analysis of endoplasmic reticulum stress-related gene (ERSRG) score and some clinical traits of lung adenocarcinoma. Additionally, we developed a clinically applicable nomogram for predicting survival for LUAD patients over one, three, and five years. Moreover, we carried out a drug sensitivity analysis to identify novel small molecule compounds for LUAD treatment. Finally, we examined the tumor microenvironment (TME) and immune cell infiltrating analysis to explore the interactions between immune and cancer cells. 142 differentially expressed ERSRGs were identified by using the DESeq2 package. A prognostic model was built based on 7 differentially expressed ERSRGs after performing univariate Cox regression, LASSO regression, and multivariate Cox regression analysis. According to the results of univariate and multivariate independent prognostic analysis, we found ERSRG score can be used as an independent prognostic maker. Using the Kaplan-Meier curves, we found low-risk patients had higher survival probability than high-risk patients in both training set and test set. A nomogram was drawn to predict 1-, 3-, and 5-year survival probability. The calibration curves explained good performance of the model for the prediction of survival. Phenformin, OSU-03012, GSK-650394 and KIN001-135 were identified as the drugs most likely to provide important information to clinicians about the treatment of LUAD patients. A prognostic prediction model was established based on 7 differentially expressed ERSRGs (PDX1, IGFBP1, DDIT4, PPP1R3G, CFTR, DERL3 and NUPR1), which could effectively predict the prognosis of LUAD patients and give a reference for clinical doctors to help LUAD patients to make better treatment tactics. Based on the 4 small molecule compounds (Phenformin, OSU-03012, GSK-650394 and KIN001-135) we discovered, targeting endoplasmic reticulum stress-related genes may also be a therapeutic approach for LUAD patients.
Topics: Humans; Prognosis; Endoplasmic Reticulum Stress; Phenformin; Lung Neoplasms; Kaplan-Meier Estimate; Adenocarcinoma of Lung; Tumor Microenvironment
PubMed: 36400857
DOI: 10.1038/s41598-022-23852-z -
Cell Death & Disease Nov 2023Medulloblastoma is a cancerous brain tumor that affects mostly children. Among the four groups defined by molecular characteristics, Group 3, the least well...
Medulloblastoma is a cancerous brain tumor that affects mostly children. Among the four groups defined by molecular characteristics, Group 3, the least well characterized, is also the least favorable, with a survival rate of 50%. Current treatments, based on surgery, radiotherapy, and chemotherapy, are not adequate and the lack of understanding of the different molecular features of Group 3 tumor cells makes the development of effective therapies challenging. In this study, the problem of medulloblastoma is approached from a metabolic standpoint in a low oxygen microenvironment. We establish that Group 3 cells use both the mitochondrial glycerol-3 phosphate (G3PS) and malate-aspartate shuttles (MAS) to produce NADH. Small molecules that target G3PS and MAS show a greater ability to decrease cell proliferation and induce apoptosis specifically of Group 3 cells. In addition, as Group 3 cells show improved respiration in hypoxia, the use of Phenformin, a mitochondrial complex 1 inhibitor, alone or in combination, induced significant cell death. Furthermore, inhibition of the cytosolic NAD+ recycling enzyme lactate dehydrogenase A (LDHA), enhanced the effects of the NADH shuttle inhibitors. In a 3D model using Group 3 human cerebellar organoids, tumor cells also underwent apoptosis upon treatment with NADH shuttle inhibitors. Our study demonstrates metabolic heterogeneity depending on oxygen concentrations and provides potential therapeutic solutions for patients in Group 3 whose tumors are the most aggressive.
Topics: Child; Humans; NAD; Medulloblastoma; Cerebellar Neoplasms; Hypoxia; Oxygen; Malates; Aspartic Acid; Tumor Microenvironment
PubMed: 38036520
DOI: 10.1038/s41419-023-06275-0 -
Oncotarget Nov 2019Phenformin is a biguanide drug which, besides the original anti-diabetic effect, also exerts anti-cancer effects. The aim of this study was to further characterize these...
Phenformin is a biguanide drug which, besides the original anti-diabetic effect, also exerts anti-cancer effects. The aim of this study was to further characterize these latter in terms of both cell-viability and modulation of the secretion of the pro-tumorigenic chemokine CXCL8. Normal human thyrocytes in primary cultures (NHT) and thyroid cancer cell lines, TPC-1 and 8505C (RET/PTC and BRAFV600E mutated, respectively) were treated with increasing concentrations of phenformin at different times. Cell-viability was assessed by WST-1 and further characterized by AnnexinV/PI staining and cell proliferation colony-assay. CXCL8 levels were measured in cell supernatants. Phenformin reduced cell-viability in TPC-1 and 8505C and their ability to form colonies. In NHT cells, phenformin affected cell-viability only at the maximal dose but interestingly it inhibited CXCL8 secretion at all the concentrations not affecting cell-viability. Phenformin had no effect on CXCL8 secretion in thyroid cancer cell lines. Thus, phenformin exerts anti-cancer effects on both cancer cells (cell death induction) and surrounding normal cells (inhibition of CXCL8 secretion). These results highlight that the anti-cancer effects of phenformin are multifaceted and effective on both solid and soluble components of the tumor-microenvironment.
PubMed: 31741708
DOI: 10.18632/oncotarget.27266 -
Cell Reports Feb 2020The antidiabetic drug phenformin displays potent anticancer activity in different tumors, but its mechanism of action remains elusive. Using Shh medulloblastoma as...
The antidiabetic drug phenformin displays potent anticancer activity in different tumors, but its mechanism of action remains elusive. Using Shh medulloblastoma as model, we show here that at clinically relevant concentrations, phenformin elicits a significant therapeutic effect through a redox-dependent but complex I-independent mechanism. Phenformin inhibits mitochondrial glycerophosphate dehydrogenase (mGPD), a component of the glycerophosphate shuttle, and causes elevations of intracellular NADH content. Inhibition of mGPD mimics phenformin action and promotes an association between corepressor CtBP2 and Gli1, thereby inhibiting Hh transcriptional output and tumor growth. Because ablation of CtBP2 abrogates the therapeutic effect of phenformin in mice, these data illustrate a biguanide-mediated redox/corepressor interplay, which may represent a relevant target for tumor therapy.
Topics: Animals; Antineoplastic Agents; Co-Repressor Proteins; Hedgehog Proteins; Humans; Hypoglycemic Agents; Mice; Neoplasms; Phenformin
PubMed: 32049007
DOI: 10.1016/j.celrep.2020.01.024