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Frontiers in Oncology 2022Exosomes secreted by cancer cells are important components in the tumor microenvironment, enabling cancer cells to communicate with each other and with noncancerous...
Exosomes secreted by cancer cells are important components in the tumor microenvironment, enabling cancer cells to communicate with each other and with noncancerous cells to play important roles in tumor progression and metastasis. Phenformin, a biguanide antidiabetic drug, has been reported to have a strong antitumor function in multiple types of cancer cells, however little research has been reported about whether phenformin can regulate the secretion of exosomes by cancer cells to regulate the tumor microenvironment and contribute to its antitumor function. Here we found that exosomes (Phen-Exo) derived from phenformin-treated oral squamous cell carcinoma (OSCC) cells significantly suppress the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) . The inhibition of angiogenesis by Phen-Exo was verified by matrigel plug angiogenesis assays and by chick chorioallantoic membrane assays. Mechanistically, we discovered that the expression of microRNA-1246 (miR-1246) and microRNA-205 (miR-205) was significantly increased in exosomes secreted by OSCC cells treated with phenformin, while high expression levels of miR-1246 or miR-205 in vascular endothelial cells inhibited their angiogenic effects and decreased expression of the angiogenic factor VEGFA. In conclusion, these results reveal that phenformin can inhibit angiogenesis by regulating the levels of miR-1246 and miR-205 in exosomes secreted by OSCC cells, suggesting that phenformin has the potential to alter the tumor microenvironment to antagonize the growth of OSCCs, which provides a theoretical basis for developing new strategies to treat OSCCs in the future.
PubMed: 36158698
DOI: 10.3389/fonc.2022.943477 -
Nanoscale Advances Mar 2022Graphene is an attractive choice for the development of an effective drug carrier in cancer treatment due to its high adsorption area and pH-responsive drug affinity. In...
Graphene is an attractive choice for the development of an effective drug carrier in cancer treatment due to its high adsorption area and pH-responsive drug affinity. In combination with the highly potent metabolic drug phenformin, increased doses could be efficiently delivered to cancer cells. This study compares the use of graphene oxide (GO) and polyethylene glycol stabilized (PEGylated) pristine graphene nanosheets (PGNSs) for drug delivery applications with phenformin. The cytotoxicity and mitotoxicity of the graphene-based systems were assessed in human cells and zebrafish larvae. Targeted drug release from GO and PGNSs was evaluated at different pH levels known to arise in proliferating tumor microenvironments. PGNSs were less cytotoxic and mitotoxic than GO, and showed an increased release of phenformin at lower pH in cells, compared to GO. In addition, the systemic phenformin effect was mitigated in zebrafish larvae when bound to GO and PGNSs compared to free phenformin, as measured by flavin metabolic lifetime imaging. These results pave the way for improved phenformin-based cancer therapy using graphene nano-sheets, where PGNSs were superior to GO.
PubMed: 36134366
DOI: 10.1039/d1na00778e -
Cells Aug 2022The treatment of many skin inflammation diseases, such as psoriasis and atopic dermatitis, is still a challenge and inflammation plays important roles in multiple stages...
The treatment of many skin inflammation diseases, such as psoriasis and atopic dermatitis, is still a challenge and inflammation plays important roles in multiple stages of skin tumor development, including initiation, promotion and metastasis. Phenformin, a biguanide drug, has been shown to play a more efficient anti-tumor function than another well-known biguanide drug, metformin, which has been reported to control the expression of pro-inflammatory cytokines; however, little is known about the effects of phenformin on skin inflammation. This study used a mouse acute inflammation model, ex vivo skin organ cultures and in vitro human primary keratinocyte cultures to demonstrate that phenformin can suppress acute skin inflammatory responses induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in vivo and significantly suppresses the pro-inflammatory cytokines IL-1β, IL-6 and IL-8 in human primary keratinocytes in vitro. The suppression of pro-inflammatory cytokine expression by phenformin was not directly through regulation of the MAPK or NF-κB pathways, but by controlling the expression of c-Myc in human keratinocytes. We demonstrated that the overexpression of c-Myc can induce pro-inflammatory cytokine expression and counteract the suppressive effect of phenformin on cytokine expression in keratinocytes. In contrast, the down-regulation of c-Myc produces effects similar to phenformin, both in cytokine expression by keratinocytes in vitro and in skin inflammation in vivo. Finally, we showed that phenformin, as an AMPK activator, down-regulates the expression of c-Myc through regulation of the AMPK/mTOR pathways. In summary, phenformin inhibits the expression of pro-inflammatory cytokines in keratinocytes through the down-regulation of c-Myc expression to play an anti-inflammation function in the skin.
Topics: AMP-Activated Protein Kinases; Animals; Cytokines; Dermatitis, Atopic; Humans; Inflammation; Keratinocytes; Mice; Phenformin; Proto-Oncogene Proteins c-myc
PubMed: 35954273
DOI: 10.3390/cells11152429 -
Cell Communication and Signaling : CCS Jun 2022Bone morphogenetic proteins (BMP) are evolutionarily conserved morphogens that are reactivated in lung carcinomas. In lung cancer cells, BMP signaling suppresses AMP...
Bone morphogenetic protein inhibitors and mitochondria targeting agents synergistically induce apoptosis-inducing factor (AIF) caspase-independent cell death in lung cancer cells.
BACKGROUND
Bone morphogenetic proteins (BMP) are evolutionarily conserved morphogens that are reactivated in lung carcinomas. In lung cancer cells, BMP signaling suppresses AMP activated kinase (AMPK) by inhibiting LKB1. AMPK is activated by mitochondrial stress that inhibits ATP production, which is enhanced 100-fold when phosphorylated by LKB1. Activated AMPK can promote survival of cancer cells but its "hyperactivation" induces cell death. The studies here reveal novel cell death mechanisms induced by BMP inhibitors, together with agents targeting the mitochondria, which involves the "hyperactivation" of AMPK.
METHODS
This study examines the synergistic effects of two BMP inhibitors together with mitochondrial targeting agents phenformin and Ym155, on cell death of lung cancer cells expressing LKB1 (H1299), LKB1 null (A549), and A549 cells transfected with LKB1 (A549-LKB1). Cell death mechanisms evaluated were the activation of caspases and the nuclear localization of apoptosis inducing factor (AIF). A769662 was used to allosterically activate AMPK. Knockdown of BMPR2 and LKB1 using siRNA was used to examine their effects on nuclear localization of AMPK. Validation studies were performed on five passage zero primary NSCLC.
RESULTS
Both BMP inhibitors synergistically suppressed growth when combined with Ym155 or phenformin in cells expressing LKB1. The combination of BMP inhibitors with mitochondrial targeting agents enhanced the activation of AMPK in lung cancer cells expressing LKB1. Allosteric activation of AMPK with A769662 induced cell death in both H1299 and A549 cells. Cell death induced by the combination of BMP inhibitors and mitochondrial-targeting agents did not activate caspases. The combination of drugs induced nuclear localization of AIF in cells expressing LKB1, which was attenuated by knockdown of LKB1. Knockdown of BMPR2 together with Ym155 increased nuclear localization of AIF. Combination therapy also enhanced cell death and AIF nuclear localization in primary NSCLC.
CONCLUSIONS
These studies demonstrate that inhibition of BMP signaling together with mitochondrial targeting agents induce AIF caspase-independent cell death, which involves the "hyperactivation" of AMPK. AIF caspase-independent cell death is an evolutionarily conserved cell death pathway that is infrequently studied in cancer. These studies provide novel insight into mechanisms inducing AIF caspase-independent cell death in cancer cells using BMP inhibitors. Video Abstract.
Topics: AMP-Activated Protein Kinases; Apoptosis; Apoptosis Inducing Factor; Bone Morphogenetic Proteins; Carcinoma, Non-Small-Cell Lung; Caspases; Cell Death; Humans; Lung; Lung Neoplasms; Mitochondria; Phenformin; Protein Serine-Threonine Kinases
PubMed: 35761398
DOI: 10.1186/s12964-022-00905-4 -
RSC Advances Apr 2021A bar micro-solid phase (bar μ-SPE) extraction method using either graphene or zeolite or their mixtures as an adsorbent, coupled with high-performance liquid...
A bar micro-solid phase (bar μ-SPE) extraction method using either graphene or zeolite or their mixtures as an adsorbent, coupled with high-performance liquid chromatography (using a C1 column) was developed for the simultaneous determination of pharmaceutical compounds (metformin (MET), buformin (BUF), phenformin (PHEN) and propranolol (PROP)) of diverse polarity (log from -1.82 to 3.10). Parameters influencing the extraction, such as conditioning solvents, pH of the sample, sample volume, amount of adsorbent, stirring rate, time of extraction, type and volume of desorption solvent and time of desorption were investigated. Under the optimized conditions, the extraction method using graphene (extraction efficiency, % EE, ∼6-15%) resulted in the least amount of extracted drugs. However, the use of zeolite and zeolite/graphene mixtures improves the % EE significantly, 30% for PHEN and 42% for PROP using zeolite; 22% for MET and 18% for BUF using the adsorbent mixture. Under similar conditions, enrichment factors for these drugs range from 11-15. The validated method was performed for the determination of the drugs that were spiked to urine samples. Good recoveries ranging from 72.8 to 116% were achieved.
PubMed: 35479128
DOI: 10.1039/d1ra01569a -
Pharmaceuticals (Basel, Switzerland) Apr 2022Metformin is a widely prescribed medication for the treatment and management of type 2 diabetes. It belongs to a class of biguanides, which are characterized by a wide... (Review)
Review
Metformin is a widely prescribed medication for the treatment and management of type 2 diabetes. It belongs to a class of biguanides, which are characterized by a wide range of diverse biological properties, including anticancer, antimicrobial, antimalarial, cardioprotective and other activities. It is known that biguanides serve as excellent N-donor bidentate ligands and readily form complexes with virtually all transition metals. Recent evidence suggests that the mechanism of action of metformin and its analogues is linked to their metal-binding properties. These findings prompted us to summarize the existing data on the synthetic strategies and biological properties of various metal complexes with metformin and its analogues. We demonstrated that coordination of biologically active biguanides to various metal centers often resulted in an improved pharmacological profile, including reduced drug resistance as well as a wider spectrum of activity. In addition, coordination to the redox-active metal centers, such as Au(III), allowed for various activatable strategies, leading to the selective activation of the prodrugs and reduced off-target toxicity.
PubMed: 35455450
DOI: 10.3390/ph15040453 -
Proceedings of the National Academy of... Mar 2022SignificanceMetformin is the most commonly prescribed drug for the treatment of type 2 diabetes mellitus, yet the mechanism by which it lowers plasma glucose...
SignificanceMetformin is the most commonly prescribed drug for the treatment of type 2 diabetes mellitus, yet the mechanism by which it lowers plasma glucose concentrations has remained elusive. Most studies to date have attributed metformin's glucose-lowering effects to inhibition of complex I activity. Contrary to this hypothesis, we show that inhibition of complex I activity in vitro and in vivo does not reduce plasma glucose concentrations or inhibit hepatic gluconeogenesis. We go on to show that metformin, and the related guanides/biguanides, phenformin and galegine, inhibit complex IV activity at clinically relevant concentrations, which, in turn, results in inhibition of glycerol-3-phosphate dehydrogenase activity, increased cytosolic redox, and selective inhibition of glycerol-derived hepatic gluconeogenesis both in vitro and in vivo.
Topics: Animals; Electron Transport Complex IV; Gluconeogenesis; Glucose; Glycerol; Glycerolphosphate Dehydrogenase; Guanidines; Hypoglycemic Agents; Liver; Metformin; Oxidation-Reduction; Phenformin; Pyridines
PubMed: 35238637
DOI: 10.1073/pnas.2122287119 -
Biomedicine & Pharmacotherapy =... Mar 2022Cancer is one of the main causes of human mortality and brain tumors, including invasive pituitary adenomas, medulloblastomas and glioblastomas are common brain... (Review)
Review
Cancer is one of the main causes of human mortality and brain tumors, including invasive pituitary adenomas, medulloblastomas and glioblastomas are common brain malignancies with poor prognosis. Therefore, the development of innovative management strategies for refractory cancers and brain tumors is important. In states of mitochondrial dysfunction - commonly encountered in malignant cells - cells mostly shift to anaerobic glycolysis by increasing the expression of LDHA (Lactate Dehydrogenase-A) gene. Oxamate, an isosteric form of pyruvate, blocks LDHA activity by competing with pyruvate. By blocking LDHA, it inhibits protumorigenic cascades and also induces ROS (reactive oxygen species)-induced mitochondrial apoptosis of cancer cells. In preclinical studies, oxamate blocked the growth of invasive pituitary adenomas, medulloblastomas and glioblastomas. Oxamate also increases temozolomide and radiotherapy sensitivity of glioblastomas. Oxamate is highly polar, which may preclude its clinical utilization due to low penetrance through cell membranes. However, this obstacle could be overcome with nanoliposomes. Moreover, different oxamate analogs were developed which inhibit LDHC4, an enzyme also involved in cancer progression and germ cell physiology. Lastly, phenformin, an antidiabetic agent, exerts anticancer effects via complex I inhibition in the mitochondria and leading the overproduction of ROS. Oxamate combination with phenformin reduces the lactic acidosis-causing side effect of phenformin while inducing synergistic anticancer efficacy. In sum, oxamate as a single agent and more efficiently with phenformin has high potential to slow the progression of aggressive cancers with special emphasis to brain tumors.
Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Glycolysis; Humans; L-Lactate Dehydrogenase; Mitochondria; Neoplasms; Oxamic Acid; Phenformin; Radiation Tolerance; Reactive Oxygen Species; Temozolomide
PubMed: 35124385
DOI: 10.1016/j.biopha.2022.112686 -
STAR Protocols Mar 2022Mitochondrial electron transport chain (ETC) dysfunction elevates the NADH/NAD ratio to cause metabolic derangements. Here we describe a protocol to measure the NADH/NAD...
Mitochondrial electron transport chain (ETC) dysfunction elevates the NADH/NAD ratio to cause metabolic derangements. Here we describe a protocol to measure the NADH/NAD ratio and analyze the rewiring of glucose metabolism using [4-H]-glucose, [3-H]-glucose, and [U-C]-glucose in ETC-inhibited human cancer cells. We also describe a protocol to analyze the NADH/NAD ratio-sensitive metabolites in mouse plasma and mouse liver following phenformin treatment. These protocols comprehensively analyze the metabolic derangements resulting from increased NADH/NAD ratio in and models. For complete details on the use and execution of this profile, please refer to Liu et al. (2021).
Topics: Animals; Cell Line; Glucose; Metabolic Diseases; Mice; NAD; Oxidation-Reduction
PubMed: 35106502
DOI: 10.1016/j.xpro.2021.101120 -
The Journal of Toxicological Sciences 2022The liver microphysiological system (MPS) model is an in-vitro culture method that mimics physiological blood flow, which enhances basal cellular functions. However, the...
The liver microphysiological system (MPS) model is an in-vitro culture method that mimics physiological blood flow, which enhances basal cellular functions. However, the liver MPS model has not been tested in the preclinical stage because of its obscure utility. It can overcome the major problem of conventional systems-rapid loss of mitochondrial activity in cultured hepatocytes due to limited oxygen supply-by supplying oxygen to cultured hepatocytes using a perfusion device. In this study, we developed a new perfusion culture system that can detect mitochondrial toxicity. Primary mouse hepatocytes were cultured under perfusion condition for 48 hr. The hepatocytes showed increased oxygen consumption and reduced lactate release. These results indicated that the ATP-production pathway was switched from glycolysis to mitochondrial oxidative phosphorylation in the perfusion culture system. Furthermore, ATP levels were considerably reduced in the perfusion culture system after exposure to phenformin, a mitochondrial complex I inhibitor. To summarize, the perfusion culture system could improve the mitochondrial activity in primary mouse hepatocytes, and thus, has potential implications in the detection of mitochondrial toxicity.
Topics: Animals; Cells, Cultured; Glycolysis; Hepatocytes; Liver; Mice; Oxidative Phosphorylation; Oxygen Consumption; Perfusion
PubMed: 34987137
DOI: 10.2131/jts.47.13