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While the tumor suppressor functions of p53 have long been recognized, the contribution of p53 to numerous other aspects of disease and normal life is only now being appreciated. This burgeoning range of responses to p53 is reflected by an increasing variety of mechanisms through which p53 can function, although the ability to activate transcription remains key to p53''s modus operandi. Control of p53''s transcriptional activity is crucial for determining which p53 response is activated, a decision we must understand if we are to exploit efficiently the next generation of drugs that selectively activate or inhibit p53. [Copyright &y& Elsevier]

Cell death, as a foil to cell expansion, has become one of the most intensively studied research areas of modern biology. Almost every aspect of life is intimately enmeshed with the proper regulation of cell death, which either contributes to or forms the basis of most human disease pathogenesis. Now, with our ever-expanding knowledge of the various death pathways, comes the hope that we might harness cell death—by either inhibition or promotion—to translate the concepts into cure. [Copyright &y& Elsevier]

This article focuses on p53 protein's role in tumor suppression. The potent growth inhibitory activities of p53 that play such a useful role in preventing the outgrowth of cells with malignant tendencies are also extremely detrimental to normal growth and development. p53 activity is therefore usually kept under very tight control, in large part by the rapid turnover of the p53 protein, which is expressed in normal tissues at extremely low levels. Research groups have come to essentially the same conclusion that the presence of a mutant p53 influences the process of tumorigenesis in a manner that can be distinct from simply deleting wild-type p53.

Examines the operation of p53, a protein involved in programmed cell death. Activation of cell cycle arrest, senescence and differentiation; Elimination of stressed or abnormal cells; Induction or repression of large and growing number of genes; Implementation of the death sentence by p53.

p53 is a key tumor suppressor protein that has numerous functions. Its primary mode of action has generally been ascribed to the induction of cell-cycle arrest, apoptosis, or senescence upon stress. Li et al. challenge this dogma with evidence that all three of these programs are dispensable for p53''s tumor suppressive role. [Copyright &y& Elsevier]

For our special issue on stress , we asked scientists about recovering from the stress of the pandemic, including some who shared insights with us in mid-2020. They discuss the importance of teamwork, reassessing priorities, and the added stresses of the cost-of-living crisis, funding cuts, and retaining scientists in academia. [ABSTRACT FROM AUTHOR]

Recent evidence reveals an unexpected role for the linker histone H1.2 in DNA damage-induced apoptosis. DNA double strand breaks induce translocation of nuclear H1.2 to the cytoplasm, where it promotes release of cytochrome c from mitochondria by activating the Bcl-2 family protein, Bak. [Copyright &y& Elsevier]

In this issue of Molecular Cell, Lewis et al. (2014) describe a new method to determine where in the cell NADPH is produced, contributing to a growing appreciation that the THF cycle is an important source of mitochondrial NADPH. In this issue of Molecular Cell, Lewis et al. (2014) describe a new method to determine where in the cell NADPH is produced and the importance of the THF cycle in producing NADHP. [ABSTRACT FROM AUTHOR]

Summary Crosstalk between cellular metabolism and the epigenome regulates epigenetic and metabolic homeostasis and normal cell behavior. Changes in cancer cell metabolism can directly impact epigenetic regulation and promote transformation. Here we analyzed the contribution of methionine and serine metabolism to methylation of DNA and RNA. Serine can contribute to this pathway by providing one-carbon units to regenerate methionine from homocysteine. While we observed this contribution under methionine-depleted conditions, unexpectedly, we found that serine supported the methionine cycle in the presence and absence of methionine through de novo ATP synthesis. Serine starvation increased the methionine/ S -adenosyl methionine ratio, decreasing the transfer of methyl groups to DNA and RNA. While serine starvation dramatically decreased ATP levels, this was accompanied by lower AMP and did not activate AMPK. This work highlights the difference between ATP turnover and new ATP synthesis and defines a vital function of nucleotide synthesis beyond making nucleic acids. [ABSTRACT FROM AUTHOR]

Summary: p53 is a transcription factor that mediates tumor suppressor responses. Correct folding of the p53 protein is essential for these activities, and point mutations that induce conformational instability of p53 are frequently found in cancers. These mutant p53s not only lose wild-type activity but can also acquire the ability to promote invasion and metastasis. We show that folding of wild-type p53 is promoted by an interaction with the chaperonin CCT. Depletion of this chaperone in cells results in the accumulation of misfolded p53, leading to a reduction in p53-dependent gene expression. Intriguingly, p53 proteins mutated to prevent the interaction with CCT show conformational instability and acquire an ability to promote invasion and random motility that is similar to the activity of tumor-derived p53 mutants. Our data therefore suggest that both growth suppression and cell invasion may be differentially regulated functions of wild-type p53. [Copyright &y& Elsevier]

Summary: The p53 tumor-suppressor protein prevents cancer development through various mechanisms, including the induction of cell-cycle arrest, apoptosis, and the maintenance of genome stability. We have identified a p53-inducible gene named TIGAR (TP53-induced glycolysis and apoptosis regulator). TIGAR expression lowered fructose-2,6-bisphosphate levels in cells, resulting in an inhibition of glycolysis and an overall decrease in intracellular reactive oxygen species (ROS) levels. These functions of TIGAR correlated with an ability to protect cells from ROS-associated apoptosis, and consequently, knockdown of endogenous TIGAR expression sensitized cells to p53-induced death. Expression of TIGAR may therefore modulate the apoptotic response to p53, allowing survival in the face of mild or transient stress signals that may be reversed or repaired. The decrease of intracellular ROS levels in response to TIGAR may also play a role in the ability of p53 to protect from the accumulation of genomic damage. [Copyright &y& Elsevier]

The last 50 years have witnessed extraordinary developments in understanding mechanisms of carcinogenesis, synthesized as the hallmarks of cancer. Despite this logical framework, our understanding of the molecular basis of systemic manifestations and the underlying causes of cancer-related death remains incomplete. Looking forward, elucidating how tumors interact with distant organs and how multifaceted environmental and physiological parameters impinge on tumors and their hosts will be crucial for advances in preventing and more effectively treating human cancers. In this perspective, we discuss complexities of cancer as a systemic disease, including tumor initiation and promotion, tumor micro- and immune macro-environments, aging, metabolism and obesity, cancer cachexia, circadian rhythms, nervous system interactions, tumor-related thrombosis, and the microbiome. Model systems incorporating human genetic variation will be essential to decipher the mechanistic basis of these phenomena and unravel gene-environment interactions, providing a modern synthesis of molecular oncology that is primed to prevent cancers and improve patient quality of life and cancer outcomes., Competing Interests: Declaration of interests C.A. reports employment at Saga Diagnostics and reports options to own stock in the company. C.A. and C.S. are listed as inventors on a European patent application relating to assay technology to detect tumor recurrence (PCT/GB2017/053289). This patent has been licensed to commercial entities and, under their terms of employment, C.A. and C.S. are due a revenue share of any revenue generated from such license(s). C.A. and C.S. declare a patent application (PCT/US2017/028013) for methods to detect lung cancer. C.A. and C.S. are named inventors on a patent application to determine methods and systems for tumor monitoring (PCT/EP2022/077987). C.A. and C.S. are named inventors on a provisional patent protection related to a ctDNA detection algorithm. J.A.J. has received honoraria for speaking at research symposia organized by Bristol Meyers Squibb and Glenmark Pharmaceuticals and previously served on the SAB of Pionyr Immunotherapeutics. D.H. is a founder and member of the BoD and SAB of Opna Bio, and a member of the SABs of Pfizer, Cellestia Biotech, 4D Molecular Therapeutics, and AtG Therapeutics. F.A. reports travel/accommodation/expenses from AstraZeneca, GlaxoSmithKline, Novartis, Pfizer, and Roche, and his institution has received research funding from AstraZeneca, Daiichi Sankyo, Lilly, Novartis, Pfizer, and Roche. C.M. Consultant/Advisory fees from Amgen, Astellas, AstraZeneca, Bayer, BeiGene, BMS, Celgene, Debiopharm, Genentech, Ipsen, Janssen, Lilly, MedImmune, MSD, Novartis, Pfizer, Roche, Sanofi, Orion. Principal/sub-Investigator of Clinical Trials for AbbVie, Aduro, Agios, Amgen, Argen-x, Astex, AstraZeneca, Aveo pharmaceuticals, Bayer, Beigene, Blueprint, BMS, Boeringer Ingelheim, Celgene, Chugai, Clovis, Daiichi Sankyo, Debiopharm, Eisai, Eos, Exelixis, Forma, Gamamabs, Genentech, Gortec, GSK, H3 biomedecine, Incyte, InnatePharma, Janssen, Kura Oncology, Kyowa, Lilly, Loxo, Lysarc, Lytix Biopharma, Medimmune, Menarini, Merus, MSD, Nanobiotix, Nektar Therapeutics, Novartis, Octimet, Oncoethix, Oncopeptides AB, Orion, Pfizer, Pharmamar, Pierre Fabre, Roche, Sanofi, Servier, Sierra Oncology, Taiho, Takeda, Tesaro, and Xencor. R.B. is founder of Oncosence. M.A.F. is founder and shareholder of Celesta Therapeutics. A.H. is a paid consultant for Calida Therapeutics. M.J.-H. has consulted for, and is a member of, the Achilles Therapeutics Scientific Advisory Board and Steering Committee, has received speaker honoraria from Pfizer, Astex Pharmaceuticals, Oslo Cancer Cluster, Bristol Myers Squibb, and is listed as a co-inventor on a European patent application relating to methods to detect lung cancer PCT/US2017/028013), this patent has been licensed to commercial entities and, under terms of employment, M.J.-H. is due a share of any revenue generated from such license(s). J.W.L. advises Restoration Foodworks, Nanocare Technologies, and Cornerstone Pharmaceuticals. S.L. received research funding to institution from Novartis, Bristol Myers Squibb, MSD, Puma Biotechnology, Eli Lilly, Nektar Therapeutics, AstraZeneca/Daiichi Sankyo, and Seattle Genetics. S.L. has acted as consultant (not compensated) to Seattle Genetics, Novartis, Bristol Myers Squibb, MSD, AstraZeneca/Daiichi Sankyo, Eli Lilly, Pfizer, Gilead Therapeutics, Nektar Therapeutics, PUMA Biotechnologies and Roche-Genentech. S.L. has acted as consultant (paid to institution) to Novartis, GlaxoSmithKline, Roche-Genentech, AstraZeneca/Daiichi Sankyo, Pfizer, Gilead Therapeutics, Seattle Genetics, MSD, Tallac Therapeutics, Eli Lilly, and Bristol Myers Squibb. I.M. is a consultant of LIfT BioSciences. K.M. has received honoraria from LEO Pharma, Pfizer and Bayer PLC. She has received research funding from LEO Pharma and Bayer PLC. S.Q. is a founder, CSO, and holds stock options in Achilles Therapeutics. C.S. acknowledges grants from AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Pfizer, Roche-Ventana, Invitae (previously Archer Dx Inc—collaboration in minimal residual disease sequencing technologies), Ono Pharmaceutical, and Personalis. He is Chief Investigator for the AZ MeRmaiD 1 and 2 clinical trials and is the Steering Committee Chair. He is also Co-Chief Investigator of the NHS Galleri trial funded by GRAIL and a paid member of GRAIL’s Scientific Advisory Board. He receives consultant fees from Achilles Therapeutics (also SAB member), Bicycle Therapeutics (also a SAB member), Genentech, Medicxi, China Innovation Centre of Roche (CICoR) formerly Roche Innovation Centre—Shanghai, Metabomed (until July 2022), Relay Therapeutics, and the Sarah Cannon Research Institute. C.S. has received honoraria from Amgen, AstraZeneca, Bristol Myers Squibb, GlaxoSmithKline, Illumina, MSD, Novartis, Pfizer, and Roche-Ventana. C.S. has previously held stock options in Apogen Biotechnologies and GRAIL, and currently has stock options in Epic Bioscience, Bicycle Therapeutics, and has stock options and is co-founder of Achilles Therapeutics. Patents: C.S. declares a patent application (PCT/US2017/028013) for methods to lung cancer); targeting neoantigens (PCT/EP2016/059401); identifying patent response to immune checkpoint blockade (PCT/EP2016/071471), determining HLA LOH (PCT/GB2018/052004); predicting survival rates of patients with cancer (PCT/GB2020/050221); identifying patients who respond to cancer treatment (PCT/GB2018/051912); methods for lung cancer detection (US20190106751A1). C.S. is an inventor on a European patent application (PCT/GB2017/053289) relating to assay technology to detect tumor recurrence. This patent has been licensed to a commercial entity and under their terms of employment C.S. is due a revenue share of any revenue generated from such license(s). K.H.V. is on the board of directors and shareholder of Bristol Myers Squibb and on the science advisory board (with stock options) of PMV Pharma, RAZE Therapeutics, Volastra Pharmaceuticals and Kovina Therapeutics. She is on the SAB of Ludwig Cancer and a co-founder and consultant of Faeth Therapeutics. She has been in receipt of research funding from Astex Pharmaceuticals and AstraZeneca and contributed to CRUK Cancer Research Technology filing of patent application WO/2017/144877. J.W. is an inventor on a US patent application (PCT/US17/53.717) submitted by the University of Texas MD Anderson Cancer Center which covers methods to enhance immune checkpoint blockade responses by modulating the microbiome, reports compensation for speaker’s bureau and honoraria from Imedex, Dava Oncology, Omniprex, Illumina, Gilead, PeerView, Physician Education Resource, MedImmune, Exelixis and Bristol Myers Squibb, and has served as a consultant/advisory board member for Roche/Genentech, Novartis, AstraZeneca, GlaxoSmithKline, Bristol Myers Squibb, Micronoma, OSE therapeutics, Merck, and Everimmune. Dr. Wargo receives stock options from Micronoma and OSE therapeutics. A.W. is on the board of Regain Therapeutics., (Copyright © 2024. Published by Elsevier Inc.)

Augmented T cell function leading to host damage in autoimmunity is supported by metabolic dysregulation, making targeting immunometabolism an attractive therapeutic avenue. Canagliflozin, a type 2 diabetes drug, is a sodium glucose co-transporter 2 (SGLT2) inhibitor with known off-target effects on glutamate dehydrogenase and complex I. However, the effects of SGLT2 inhibitors on human T cell function have not been extensively explored. Here, we show that canagliflozin-treated T cells are compromised in their ability to activate, proliferate, and initiate effector functions. Canagliflozin inhibits T cell receptor signaling, impacting on ERK and mTORC1 activity, concomitantly associated with reduced c-Myc. Compromised c-Myc levels were encapsulated by a failure to engage translational machinery resulting in impaired metabolic protein and solute carrier production among others. Importantly, canagliflozin-treated T cells derived from patients with autoimmune disorders impaired their effector function. Taken together, our work highlights a potential therapeutic avenue for repurposing canagliflozin as an intervention for T cell-mediated autoimmunity., Competing Interests: Declaration of interests K.H.V. is on the board of directors and shareholder of Bristol Myers Squibb, a shareholder of GRAIL, and on the science advisory board of PMV Pharma, RAZE Therapeutics, Volastra Pharmaceuticals, and Ludwig Cancer. She is a co-founder and consultant of Faeth Therapeutics, funded by Khosla Ventures. She has been in receipt of research funding from Astex Pharmaceuticals and AstraZeneca and contributed to CRUK Cancer Research Technology filing of patent application WO/2017/144877., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes-aldehyde dehydrogenase 1 family member 2 (ALDH1L2)-produces NADPH by catabolizing 10-formyl-THF into CO 2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling., Competing Interests: Declaration of interests K.H.V. is on the board of directors and is a shareholder of Bristol Myers Squibb and is on the scientific advisory board (with stock options) of PMV Pharma, RAZE Therapeutics, Volastra Pharmaceuticals, and Kovina Therapeutics. She is on the scientific advisory board (SAB) of Ludwig Cancer and is a co-founder and consultant of Faeth Therapeutics. She has been in receipt of research funding from Astex Pharmaceuticals and AstraZeneca and contributed to the CRUK Cancer Research Technology filing of patent application WO/2017/144877. C.S. acknowledges grant support from AstraZeneca, Boehringer-Ingelheim, Bristol Myers Squibb, Pfizer, Roche-Ventana, Invitae (previously Archer Dx, Inc., collaboration in minimal residual disease sequencing technologies), Ono Pharmaceutical, and Personalis. He is an AstraZeneca advisory board member, chief investigator for the AZ MeRmaiD 1 and 2 clinical trials, co-chief investigator of the NHS Galleri trial funded by GRAIL, and a paid member of GRAIL’s SAB. He receives consultant fees from Achilles Therapeutics (also a SAB member), Bicycle Therapeutics (also a SAB member), Genentech, Medicxi, China Innovation Center of Roche (CICoR), formerly the Roche Innovation Center – Shanghai, Metabomed (until July 2022), and the Sarah Cannon Research Institute. C.S. has received honoraria from Amgen, AstraZeneca, Pfizer, Novartis, GlaxoSmithKline, MSD, Bristol Myers Squibb, Illumina, and Roche-Ventana. C.S. had stock options in Apogen Biotechnologies and GRAIL until June 2021 and currently has stock options in Epic Bioscience and Bicycle Therapeutics and has stock options and is co-founder of Achilles Therapeutics., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The concept that dietary changes could improve the response to cancer therapy is extremely attractive to many patients, who are highly motivated to take control of at least some aspect of their treatment. Growing insight into cancer metabolism is highlighting the importance of nutrient supply to tumor development and therapeutic response. Cancers show diverse metabolic requirements, influenced by factors such as tissue of origin, microenvironment, and genetics. Dietary modulation will therefore need to be matched to the specific characteristics of both cancers and treatment, a precision approach requiring a detailed understanding of the mechanisms that determine the metabolic vulnerabilities of each cancer., Competing Interests: Declaration of Interests K.H.V. is on the Board of Directors and shareholder of Bristol Myers Squibb, a shareholder of GRAIL Inc, and on the Science Advisory Board (with stock options) of PMV Pharma, RAZE Therapeutics, and Volastra Therapeutics. She is also on the Scientific Advisory Board of Ludwig Cancer. K.H.V. is a co-founder and consultant of Faeth Therapeutics, funded by Khosla Ventures. She has been in receipt of research funding from Astex Pharmaceuticals and AstraZeneca and contributed to CRUK Cancer Research Technology filing of patent application WO/2017/144877., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The TIGAR protein has antioxidant activity that supports intestinal tissue repair and adenoma development. Using a pancreatic ductal adenocarcinoma (PDAC) model, we show that reactive oxygen species (ROS) regulation by TIGAR supports premalignant tumor initiation while restricting metastasis. Increased ROS in PDAC cells drives a phenotypic switch that increases migration, invasion, and metastatic capacity. This switch is dependent on increased activation of MAPK signaling and can be reverted by antioxidant treatment. In mouse and human, TIGAR expression is modulated during PDAC development, with higher TIGAR levels in premalignant lesions and lower TIGAR levels in metastasizing tumors. Our study indicates that temporal, dynamic control of ROS underpins full malignant progression and helps to rationalize conflicting reports of pro- and anti-tumor effects of antioxidant treatment., Competing Interests: Declaration of Interests K.H.V. is on the board of directors and a shareholder of Bristol Myers Squibb, a shareholder of GRAIL, Inc., and on the science advisory board of PMV Pharma, RAZE Therapeutics, Volestra Therapeutics,Inc and Ludwig Cancer. She is a co-founder and consultant of Faeth Therapeutics, funded by Khosla Ventures. She has been in receipt of research funding from Astex Pharmaceuticals and AstraZeneca and contributed to CRUK Cancer Research Technology filing of Patent Application WO/2017/144877. D.A.T. serves on the scientific advisory board and holds shares in Leap Therapeutics and Surface Oncology. D.A.T. serves on the SAB of Cygnal Therapeutics. D.A.T. has research support from ONO Therapeutics, FibroGen, and Halozyme., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Loss of p53 function contributes to the development of many cancers. While cell-autonomous consequences of p53 mutation have been studied extensively, the role of p53 in regulating the anti-tumor immune response is still poorly understood. Here, we show that loss of p53 in cancer cells modulates the tumor-immune landscape to circumvent immune destruction. Deletion of p53 promotes the recruitment and instruction of suppressive myeloid CD11b + cells, in part through increased expression of CXCR3/CCR2-associated chemokines and macrophage colony-stimulating factor (M-CSF), and attenuates the CD4 + T helper 1 (Th1) and CD8 + T cell responses in vivo. p53-null tumors also show an accumulation of suppressive regulatory T (Treg) cells. Finally, we show that two key drivers of tumorigenesis, activation of KRAS and deletion of p53, cooperate to promote immune tolerance., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Cancer metastasis depends on cell survival following loss of extracellular matrix attachment and dissemination through the circulation. The metastatic spread can be enhanced by the clustering of detached cancer cells and increased antioxidant defense. Here, we link these responses by describing how cell clustering limits reactive oxygen species (ROS). Loss of attachment causes mitochondrial perturbations and increased ROS production. The formation of cell clusters induces a hypoxic environment that drives hypoxia-inducible factor 1-alpha (Hif1α)-mediated mitophagy, clearing damaged mitochondria and limiting ROS. However, hypoxia and reduced mitochondrial capacity promote dependence on glycolysis for ATP production that is supported by cytosolic reductive metabolism. Preventing this metabolic adaptation or disruption of cell clusters results in ROS accumulation, cell death, and a reduction of metastatic capacity in vivo. Our results provide a mechanistic explanation for the role of cell clustering in supporting survival during extracellular matrix detachment and metastatic spread and may point to targetable vulnerabilities., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Numerous mechanisms to support cells under conditions of transient nutrient starvation have been described. Several functions of the tumor-suppressor protein p53 can contribute to the adaptation of cells to metabolic stress and help cancer cell survival under nutrient-limiting conditions. We show here that p53 promotes the expression of SLC1A3, an aspartate/glutamate transporter that allows the utilization of aspartate to support cells in the absence of extracellular glutamine. Under glutamine deprivation, SLC1A3 expression maintains electron transport chain and tricarboxylic acid cycle activity, promoting de novo glutamate, glutamine, and nucleotide synthesis to rescue cell viability. Tumor cells with high levels of SLC1A3 expression are resistant to glutamine starvation, and SLC1A3 depletion retards the growth of these cells in vitro and in vivo, suggesting a therapeutic potential for SLC1A3 inhibition., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Cancers can derive metabolic support from the stromal cells that surround them. A new study in Cell Metabolism (Yang et al., 2016) describes how ovarian cancer cells can satisfy their need for glutamine by stimulating glutamine production in adjacent fibroblasts, highlighting a metabolic dependence that might be targeted for therapy., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Previous work has shown that some cancer cells are highly dependent on serine/glycine uptake for proliferation. Although serine and glycine can be interconverted and either might be used for nucleotide synthesis and one-carbon metabolism, we show that exogenous glycine cannot replace serine to support cancer cell proliferation. Cancer cells selectively consumed exogenous serine, which was converted to intracellular glycine and one-carbon units for building nucleotides. Restriction of exogenous glycine or depletion of the glycine cleavage system did not impede proliferation. In the absence of serine, uptake of exogenous glycine was unable to support nucleotide synthesis. Indeed, higher concentrations of glycine inhibited proliferation. Under these conditions, glycine was converted to serine, a reaction that would deplete the one-carbon pool. Providing one-carbon units by adding formate rescued nucleotide synthesis and growth of glycine-fed cells. We conclude that nucleotide synthesis and cancer cell proliferation are supported by serine--rather than glycine--consumption., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

Many different types of cancer show a high incidence of TP53 mutations, leading to the expression of mutant p53 proteins. There is growing evidence that these mutant p53s have both lost wild-type p53 tumor suppressor activity and gained functions that help to contribute to malignant progression. Understanding the functions of mutant p53 will help in the development of new therapeutic approaches that may be useful in a broad range of cancer types., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

The function of p53 is best understood in response to genotoxic stress, but increasing evidence suggests that p53 also plays a key role in the regulation of metabolic homeostasis. p53 and its family members directly influence various metabolic pathways, enabling cells to respond to metabolic stress. These functions are likely to be important for restraining the development of cancer but could also have a profound effect on the development of metabolic diseases, including diabetes. A better understanding of the metabolic functions of p53 family members may aid in the identification of therapeutic targets and reveal novel uses for p53-modulating drugs., (Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.)

Regulation of metabolic pathways plays an important role in controlling cell growth, proliferation, and survival. TIGAR acts as a fructose-2,6-bisphosphatase, potentially promoting the pentose phosphate pathway to produce NADPH for antioxidant function and ribose-5-phosphate for nucleotide synthesis. The functions of TIGAR were dispensable for normal growth and development in mice but played a key role in allowing intestinal regeneration in vivo and in ex vivo cultures, where growth defects due to lack of TIGAR were rescued by ROS scavengers and nucleosides. In a mouse intestinal adenoma model, TIGAR deficiency decreased tumor burden and increased survival, while elevated expression of TIGAR in human colon tumors suggested that deregulated TIGAR supports cancer progression. Our study demonstrates the importance of TIGAR in regulating metabolism for regeneration and cancer development and identifies TIGAR as a potential therapeutic target in diseases such as ulcerative colitis and intestinal cancer., (Copyright © 2013 Elsevier Inc. All rights reserved.)

p53 is a tumor suppressor protein whose function is frequently lost in cancers through missense mutations within the Tp53 gene. This results in the expression of point-mutated p53 proteins that have both lost wild-type tumor suppressor activity and show gain of functions that contribute to transformation and metastasis. Here, we show that mutant p53 expression can promote invasion, loss of directionality of migration, and metastatic behavior. These activities of p53 reflect enhanced integrin and epidermal growth factor receptor (EGFR) trafficking, which depends on Rab-coupling protein (RCP) and results in constitutive activation of EGFR/integrin signaling. We provide evidence that mutant p53 promotes cell invasion via the inhibition of TAp63, and simultaneous loss of p53 and TAp63 recapitulates the phenotype of mutant p53 in cells. These findings open the possibility that blocking alpha5/beta1-integrin and/or the EGF receptor will have therapeutic benefit in mutant p53-expressing cancers., (Copyright 2009 Elsevier Inc. All rights reserved.)

The p53 tumor suppressor protein is regulated by its interaction with HDM2, which serves as a ubiquitin ligase (E3) to target p53 for degradation. We have identified a family of small molecules (HLI98) that inhibits HDM2's E3 activity. These compounds show some specificity for HDM2 in vitro, although at higher concentrations effects on unrelated RING and HECT domain E3s are detectable, which could be due, at least in part, to effects on E2-ubiquitin thiol-ester levels. In cells, the compounds allow the stabilization of p53 and HDM2 and activation of p53-dependent transcription and apoptosis, although other p53-independent toxicity was also observed.

The HDM2 protein plays an important role in regulating the stability and function of the p53 tumor suppressor protein. In this report, we show that the ribosomal protein L11 can interact with HDM2 and inhibit HDM2 function, thus leading to the stabilization and activation of p53. The inhibition of HDM2 activity by L11 shows some similarity to the previously described activity of ARF, and expression of either ARF or L11 can induce a p53 response. Enhancement of the interaction between endogenous L11 and HDM2 following treatment of cells with low levels of actinomycin-D suggests that the HDM2/L11 interaction represents a novel pathway for p53 stabilization in response to perturbations in ribosome biogenesis.

Cells can respond to the activation of the tumor suppressor protein p53 by undergoing cell cycle arrest or apoptosis, and Myc has now been shown to help switch the response to apoptosis by repressing the expression of p21(CIP1), a cyclin-dependent kinase inhibitor with antiapoptotic activity.