Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of the antidiabetic drug metformin on tumor growth was investigated using the paired isogenic colon cancer cell lines HCT116 p53(+/+) and HCT116 p53(-/-). Treatment with metformin selectively suppressed the tumor growth of HCT116 p53(-/-) xenografts. Following treatment with metformin, we detected increased apoptosis in p53(-/-) tumor sections and an enhanced susceptibility of p53(-/-) cells to undergo apoptosis in vitro when subject to nutrient deprivation. Metformin is proposed to function in diabetes treatment as an indirect activator of AMP-activated protein kinase (AMPK). Treatment with AICAR, another AMPK activator, also showed a selective ability to inhibit p53(-/-) tumor growth in vivo. In the presence of either of the two drugs, HCT116 p53(+/+) cells, but not HCT116 p53(-/-) cells, activated autophagy. A similar p53-dependent induction of autophagy was observed when nontransformed mouse embryo fibroblasts were treated. Treatment with either metformin or AICAR also led to enhanced fatty acid beta-oxidation in p53(+/+) MEFs, but not in p53(-/-) MEFs. However, the magnitude of induction was significantly lower in metformin-treated cells, as metformin treatment also suppressed mitochondrial electron transport. Metformin-treated cells compensated for this suppression of oxidative phosphorylation by increasing their rate of glycolysis in a p53-dependent manner. Together, these data suggest that metformin treatment forces a metabolic conversion that p53(-/-) cells are unable to execute. Thus, metformin is selectively toxic to p53-deficient cells and provides a potential mechanism for the reduced incidence of tumors observed in patients being treated with metformin.
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PMID:Systemic treatment with the antidiabetic drug metformin selectively impairs p53-deficient tumor cell growth. 1763 85

Targeting cancer cell metabolism is a new promising strategy to fight cancer. Metformin, a widely used antidiabetic agent, exerts antitumoral and antiproliferative action. In this study, the addition of metformin to 2-deoxyglucose (2DG) inhibited mitochondrial respiration and glycolysis in prostate cancer cells leading to a severe depletion in ATP. The combination of the two drugs was much more harmful for cancer cells than the treatment with metformin or 2DG alone, leading to 96% inhibition of cell viability in LNCaP prostate cancer cells. In contrast, a moderate effect on cell viability was observed in normal prostate epithelial cells. At the cellular level, the combination of metformin and 2DG induced p53-dependent apoptosis via the energy sensor pathway AMP kinase, and the reexpression of a functional p53 in p53-deficient prostate cancer cells restored caspase-3 activity. In addition to apoptosis, the combination of metformin and 2DG arrested prostate cancer cells in G(2)-M. This G(2)-M arrest was independent of p53 and correlated with a stronger decrease in cell viability than obtained with either drug. Finally, metformin inhibited 2DG-induced autophagy, decreased beclin 1 expression, and triggered a switch from a survival process to cell death. Our study reinforces the growing interest of metabolic perturbators in cancer therapy and highlights the potential use of the combination of metformin and 2DG as an anticancerous treatment.
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PMID:Targeting cancer cell metabolism: the combination of metformin and 2-deoxyglucose induces p53-dependent apoptosis in prostate cancer cells. 2021

Targeting cancer cell metabolism is a new promising strategy to fight cancer. Metformin, a widely used antidiabetic agent, and 2-deoxyglucose (2DG) drastically affect cancer cell metabolism. Recently, we showed that the combination of the two drugs was much more harmful for cancer cells than the treatment with metformin or 2DG alone. At the cellular level, this combination leads to p53- and AMPK-dependent apoptosis. Furthermore, we showed that metformin inhibits 2DG-induced autophagy, decreases beclin 1 expression and triggers a switch from a survival process to cell death.
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PMID:The combination of metformin and 2-deoxyglucose inhibits autophagy and induces AMPK-dependent apoptosis in prostate cancer cells. 2055 23

Metformin is a widely prescribed antidiabetic drug associated with a reduced risk of cancer. Many studies show that metformin inhibits cancer cell viability through the inhibition of mTOR. We recently showed that antiproliferative action of metformin in prostate cancer cell lines is not mediated by AMP-activated protein kinase (AMPK). We identified REDD1 (also known as DDIT4 and RTP801), a negative regulator of mTOR, as a new molecular target of metformin. We show that metformin increases REDD1 expression in a p53-dependent manner. REDD1 invalidation, using siRNA or REDD1(-/-) cells, abrogates metformin inhibition of mTOR. Importantly, inhibition of REDD1 reverses metformin-induced cell-cycle arrest and significantly protects from the deleterious effects of metformin on cell transformation. Finally, we show the contribution of p53 in mediating metformin action in prostate cancer cells. These results highlight the p53/REDD1 axis as a new molecular target in anticancer therapy in response to metformin treatment.
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PMID:Metformin, independent of AMPK, induces mTOR inhibition and cell-cycle arrest through REDD1. 2154 Feb 36

Metformin may reduce the incidence of breast cancer and enhance response to neoadjuvant chemotherapy in diabetic women. This trial examined the effects of metformin on Ki67 and gene expression in primary breast cancer. Non-diabetic women with operable invasive breast cancer received pre-operative metformin. A pilot cohort of eight patients had core biopsy of the cancer at presentation, a week later (without treatment; internal control), then following metformin 500-mg o.d. for 1 week increased to 1-g b.d. for a further week continued to surgery. A further 47 patients had core biopsy at diagnosis were randomized to metformin (the same dose regimen) or no drug, and 2 weeks later had core biopsy at surgery. Ki67 immunohistochemistry, transcriptome analysis on formalin-fixed paraffin-embedded cores and serum insulin determination were performed blinded to treatment. Seven patients (7/32, 21.9%) receiving metformin withdrew because of gastrointestinal upset. The mean percentage of cells staining for Ki67 fell significantly following metformin treatment in both the pilot cohort (P = 0.041, paired t-test) and in the metformin arm (P = 0.027, Wilcoxon rank test) but was unchanged in the internal control or metformin control arms. Messenger RNA expression was significantly downregulated by metformin for PDE3B (phosphodiesterase 3B, cGMP-inhibited; a critical regulator of cAMP levels that affect activation of AMP-activated protein kinase, AMPK), confirmed by immunohistochemistry, SSR3, TP53 and CCDC14. By ingenuity pathway analysis, the tumour necrosis factor receptor 1 (TNFR1) signaling pathway was most affected by metformin: TGFB and MEKK were upregulated and cdc42 downregulated; mTOR and AMPK pathways were also affected. Gene set analysis additionally revealed that p53, BRCA1 and cell cycle pathways also had reduced expression following metformin. Mean serum insulin remained stable in patients receiving metformin but rose in control patients. This trial presents biomarker evidence for anti-proliferative effects of metformin in women with breast cancer and provides support for therapeutic trials of metformin.
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PMID:Evidence for biological effects of metformin in operable breast cancer: a pre-operative, window-of-opportunity, randomized trial. 2165 90

Metformin is the most widely used antidiabetic drug for type II diabetes in the world. Recent studies provide clues that the use of metformin may be associated with reduced incidence and improved prognosis of certain cancers and there is increasing evidence of a potential efficacy of this agent as an anticancer drug. This observation led us to hypothesize that metformin might inhibit human breast cancer cells (MCF-7) growth. Here, we report that metformin induced apoptosis in human breast carcinoma cell lines MCF-7 cells via novel signaling pathway. Metformin induced apoptosis by arresting cells in G1 phase and reducing cyclin D level and increasing the expression of p21 and cyclin E. Molecular and cellular studies indicated that metformin significantly elevated p53 and Bax levels and reduced STAT3 and Bcl-2. Inhibitors of signaling proteins were used to study the mechanism(s) of metformin function. Receptor inhibitor studies indicated that p53 activation was mediated through insulin receptor (IR), not insulin-like growth factor-1 receptor (IGF-IR). Furthermore, MEK inhibitor significantly suppressed metformin-induced p53 and Bax elevation while ERK inhibitor generated a slight reduction in p53 levels. In contrast, PI3K inhibitor did not produce any effect on the metformin-elevated p53 levels. Finally, SAPK/JNK, known to be involved in apoptosis, was activated in cells treated with metformin and the activation appeared to occur downstream of ERK. All these results suggested that metformin activated p53, Bax, and induced tumor cell apoptosis through the ERK signaling pathway. This pathway has not been previously described for IR, p53, Bax activation, or apoptosis. Metformin, a novel inducer of apoptosis, and its analogs may offer a novel strategy for the treatment of cancer cells.
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PMID:Antidiabetic drug metformin induces apoptosis in human MCF breast cancer via targeting ERK signaling. 2177 23

The in vitro and in vivo anti-melanoma effect of antidiabetic drug metformin was investigated using B16 mouse melanoma cell line. Metformin caused a G(2)/M cell cycle arrest associated with apoptotic death of melanoma cells, as confirmed by the flow cytometric analysis of cell cycle/DNA fragmentation, phosphatidylserine exposure and caspase activation. Metformin-mediated apoptosis of melanoma cells was preceded by induction of oxidative stress and mitochondrial membrane depolarization, measured by flow cytometry in cells stained with appropriate fluorescent reporter dyes. The expression of tumor suppressor protein p53 was increased, while the mRNA levels of anti-apoptotic Bcl-2 were reduced by metformin, as revealed by cell-based ELISA and real-time RT-PCR, respectively. Treatment with metformin did not stimulate expression of the cycle blocker p21, indicating that p21 was dispensable for the observed cell cycle arrest. The activation of AMP-activated protein kinase (AMPK) was not required for the anti-melanoma action of metformin, as AMPK inhibitor compound C completely failed to restore viability of metformin-treated B16 cells. Metformin induced autophagy in B16 cells, as demonstrated by flow cytometry-detected increase in intracellular acidification and immunoblot-confirmed upregulation of autophagosome-associated LC3-II. Autophagy inhibitors ammonium chloride and wortmannin partly restored the viability of metformin-treated melanoma cells. Finally, oral administration of metformin led to a significant reduction in tumor size in a B16 mouse melanoma model. These data suggest that anti-melanoma effects of metformin are mediated through p21- and AMPK-independent cell cycle arrest, apoptosis and autophagy associated with p53/Bcl-2 modulation, mitochondrial damage and oxidative stress.
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PMID:In vitro and in vivo anti-melanoma action of metformin. 2180 81

A distinct group of breast cancers, called "basal" or "triple-negative" (TN) cancers express both basal cytokeratins and the epidermal growth factor receptor, but fail to express estrogen receptors, progesterone receptors or HER2 and have stem-like or mesenchymal features. They are particularly aggressive, are frequently chemo-resistant, with p53 mutation, up-regulation of IL-6 and Stat3. Because TN cells are particularly sensitive to the anti-diabetic agent metformin, we hypothesized that it may target JAK2/Stat3 signaling. The effects of metformin upon Stat3 expression and activation were examined in four human TN cell lines. Metformin's effects were also studied in sublines with forced over-expression of constitutively active (CA) Stat3, as well as lines with stable knockdown of Stat3. Metformin inhibited Stat3 activation (P-Stat3) at Tyr705 and Ser727 and downstream signaling in each of the four parental cell lines. CA-Stat3 transfection attenuated, whereas Stat3 knockdown enhanced, the effects of metformin upon growth inhibition and apoptosis induction. A Stat3 specific inhibitor acted synergistically with metformin in reducing cell growth and inducing apoptosis. An mTOR inhibitor showed no significant interaction with metformin. In summary, Stat3 is a critical regulator of metformin action in TN cancer cells, providing the potential for enhancing metformin's efficacy in the clinical setting.
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PMID:Metformin targets Stat3 to inhibit cell growth and induce apoptosis in triple-negative breast cancers. 2218 13

AMP-activated protein kinase (AMPK) and the NAD(+)-dependent histone/protein deacetylase sirtuin 1 (SIRT1) are metabolic sensors that can increase each other's activity. They are also both activated by the antidiabetic drug metformin and downregulated in the liver under conditions of nutrient excess (e.g., hyperglycemia, high-fat diet, obesity). In these situations, the abundance of the tumor suppressor p53 is increased; however, the relevance of this to the changes in AMPK and SIRT1 is not known. In the present study we investigated this question in HepG2 cells under high glucose conditions. Metformin induced activation of AMPK and SIRT1 and decreased p53 protein abundance. It also decreased triglyceride accumulation and cytosolic oxidative stress (a trigger for p53 accumulation) and increased the deacetylation of p53 at a SIRT1-targeted site. The decrease in p53 abundance caused by metformin was abolished by inhibition of murine double minute 2 (MDM2), a ubiquitin ligase that mediates p53 degradation, as well as by overexpression of a dominant-negative AMPK or a shRNA-mediated knockdown of SIRT1. In addition, overexpression of p53 decreased SIRT1 gene expression and protein abundance, as well as AMPK activity in metformin-treated cells. It also diminished the triglyceride-lowering action of metformin, an effect that was rescued by incubation with the SIRT1 activator SRT2183. Collectively, these findings suggest the existence of a novel reciprocal interaction between AMPK/SIRT1 and p53 that may have implications for the pathogenesis and treatment of metabolic diseases.
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PMID:A novel inverse relationship between metformin-triggered AMPK-SIRT1 signaling and p53 protein abundance in high glucose-exposed HepG2 cells. 2244 40

Metformin, a substrate of several poly-specific organic cation transporters, is a widely used biguanide for the treatment of type II diabetes. Recent studies suggest that metformin attenuates mTORC1 signalling by the activation of 5' adenosine monophosphate-activated protein kinase (AMPK) in the presence or absence of a functional hamartin/tuberin (TSC1/TSC2) complex. Metformin has also been reported to inhibit mTORC1 independent of AMPK through p53-dependent regulated in development and DNA damage responses 1 (REDD1) or by inhibiting Rag GTPases. These observations suggest that metformin could have therapeutic potential for tuberous sclerosis, an inherited disorder characterised by the aberrant activation of mTORC1 and the development of tumours in many organs, including the kidneys. In this study, we investigated the effect of metformin on renal lesions in a Tsc1(+/-) mouse model of tuberous sclerosis. Continuous treatment of metformin for 9 months at doses of up to 600 mg/kg/day had no significant effect on renal lesions in nine treated mice compared to 10 controls. Metformin treatment appeared to attenuate mTORC1 signalling in Tsc1(+/-) kidney tissues but not in renal tumours. Surprisingly, the expression of the organic cation transporters Slc22a1, Slc22a2 and Slc22a3 essential for the cellular uptake of metformin was highly suppressed in renal tumours. Treatment of cultured cells derived from a Tsc1-associated renal tumour with 5-aza-2-deoxycytidine or trichostatin A greatly increased the expression of these genes. These data suggest that the epigenetic suppression of the organic cation transporters in Tsc-associated mouse renal tumours may contribute to the lack of response to metformin treatment.
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PMID:Renal tumours in a Tsc1+/- mouse model show epigenetic suppression of organic cation transporters Slc22a1, Slc22a2 and Slc22a3, and do not respond to metformin. 2322 42


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