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Endothelial cells adopt tissue-specific characteristics to instruct organ development and regeneration1,2. This adaptability is lost in cultured adult endothelial cells, which do not vascularize tissues in an organotypic manner. Here, we show that transient reactivation of the embryonic-restricted ETS variant transcription factor 2 (ETV2)3 in mature human endothelial cells cultured in a serum-free three-dimensional matrix composed of a mixture of laminin, entactin and type-IV collagen (LEC matrix) ‘resets’ these endothelial cells to adaptable, vasculogenic cells, which form perfusable and plastic vascular plexi. Through chromatin remodelling, ETV2 induces tubulogenic pathways, including the activation of RAP1, which promotes the formation of durable lumens4,5. In three-dimensional matrices—which do not have the constraints of bioprinted scaffolds—the ‘reset’ vascular endothelial cells (R-VECs) self-assemble into stable, multilayered and branching vascular networks within scalable microfluidic chambers, which are capable of transporting human blood. In vivo, R-VECs implanted subcutaneously in mice self-organize into durable pericyte-coated vessels that functionally anastomose to the host circulation and exhibit long-lasting patterning, with no evidence of malformations or angiomas. R-VECs directly interact with cells within three-dimensional co-cultured organoids, removing the need for the restrictive synthetic semipermeable membranes that are required for organ-on-chip systems, therefore providing a physiological platform for vascularization, which we call ‘Organ-On-VascularNet’. R-VECs enable perfusion of glucose-responsive insulin-secreting human pancreatic islets, vascularize decellularized rat intestines and arborize healthy or cancerous human colon organoids. Using single-cell RNA sequencing and epigenetic profiling, we demonstrate that R-VECs establish an adaptive vascular niche that differentially adjusts and conforms to organoids and tumoroids in a tissue-specific manner. Our Organ-On-VascularNet model will permit metabolic, immunological and physiochemical studies and screens to decipher the crosstalk between organotypic endothelial cells and parenchymal cells for identification of determinants of endothelial cell heterogeneity, and could lead to advances in therapeutic organ repair and tumour targeting., The transient reactivation of ETV2 in adult human endothelial cells reprograms these cells to become adaptable vasculogenic endothelia that in three-dimensional matrices self-assemble into vascular networks that can transport blood and physiologically arborize organoids and decellularized tissues.

In utero transplantation (IUT) of hematopoietic stem cells (HSC) has been proposed as a strategy for the prenatal treatment of congenital hematological diseases. However, levels of long-term hematopoietic engraftment achieved in experimental IUT to date are sub-therapeutic, likely due to host fetal HSC out-competing their bone-marrow (BM) derived donor equivalents for space in the hematopoietic compartment. In the present study we demonstrate that amniotic fluid stem cells (AFSC; c-Kit+/Lin-) have hematopoietic characteristics and, thanks to their fetal origin, favourable proliferation kinetics in vitro and in vivo, which are maintained when the cells are expanded. IUT of autologous/congenic freshly-isolated or cultured AFSC resulted in stable mutli-lineage hematopoietic engraftment, far higher to that achieved with BM-HSC. Intravascular IUT of allogenic AFSC was not successful as recently reported after intraperitoneal IUT. Herein we demonstrated that this likely due to a failure of timely homing of donor cells to the host fetal thymus resulted in lack of tolerance induction and rejection. This study reveals that intravascular IUT leads to a remarkable hematopoietic engraftment of AFSC in the setting of autologous/congenic IUT, and confirms the requirement for induction of central tolerance for allogenic IUT to be successful. Autologous, gene engineered and in-vitro expanded AFSC could be used as a stem cell/gene therapy platform for the in utero treatment of inherited disorders of hematopoiesis. SIGNIFICANCE STATEMENT: Amniotic fluid stem cells can be expanded without losing their hematopoietic characteristics In utero transplantation of allogenic AFSC results in adaptive immune response and donor cell rejection, due to failure of timely homing of donor cells to the host fetal thymus and lack of central tolerance induction. Autologous/congenic amniotic fluid stem cells can be transplanted in utero and result in stable, multi-lineage, long-term hematopoietic engraftment that is significantly higher to that achieved with bone marrow-derived cells and could be therapeutic in many inherited disorders of hematopoiesis. © AlphaMed Press 2019.

Cancer cells require increased levels of NADPH for increased nucleotide synthesis and for protection from ROS. Recent studies show that increased NADPH is generated in several ways. Activated AKT phosphorylates NAD kinase (NADK), increasing its activity. NADP formed, is rapidly converted to NADPH by glucose 6-phosphate dehydrogenase and malic enzymes, overexpressed in tumor cells with mutant p53. Calmodulin, overexpressed in some cancers, also increases NADK activity. Also, in IDH1/2 mutant cancer, NADPH serves as the cofactor to generate D-2 hydroxyglutarate, an oncometabolite. The requirement of cancer cells for elevated levels of NADPH provides an opportunity to target its synthesis for cancer treatment.

Purpose To investigate the effectiveness of a combination of 6-thioguanine (6-TG) and pralatrexate (PDX) in methylthioadenosine phosphorylase (MTAP)-deficient T-cell acute lymphoblastic leukemia (T-cell ALL). Methods CCRF-CEM (MTAP−/−) and Molt4 (MTAP+/+) T-cell ALL cell lines were treated with 6-TG or PDX and evaluated for efficacy 72 h later. NOD/SCID gamma mice bearing CEM or Molt4 xenografts were treated with 6-TG and PDX alone or in combination to evaluate antitumor effects. Results CEM cells were more sensitive to 6-TG and PDX in vitro than Molt4. In vivo, CEM cells were very sensitive to PDX and 6-TG, whereas Molt4 cells were highly resistant to 6-TG. A well-tolerated combination of PDX and 6-TG achieved significant tumor regression in CEM xenografts. Conclusions The loss of MTAP expression may be therapeutically exploited in T-cell ALL. The combination of 6-TG and PDX, with the inclusion of leucovorin rescue, allows for a safe and effective regimen in MTAP-deficient T-cell ALL.

NAD+ kinase (NADK) catalyzes the phosphorylation of nicotinamide adenine dinucleotide (NAD+) to nicotinamide adenine dinucleotide phosphate (NADP+) using ATP as the phosphate donor. NADP+ is then reduced to NADPH by dehydrogenases, in particular glucose-6-phosphate dehydrogenase and the malic enzymes. NADPH functions as an important cofactor in a variety of metabolic and biosynthetic pathways. The demand for NADPH is particularly high in proliferating cancer cells, where it acts as a cofactor for the synthesis of nucleotides, proteins, and fatty acids. Moreover, NADPH is essential for the neutralization of the dangerously high levels of reactive oxygen species (ROS) generated by increased metabolic activity. Given its key role in metabolism and regulation of ROS, it is not surprising that several recent studies, including in vitro and in vivo assays of tumor growth and querying of patient samples, have identified NADK as a potential therapeutic target for the treatment of cancer. In this review, we will discuss the experimental evidence justifying further exploration of NADK as a clinically relevant drug target and describe our studies with a lead compound, thionicotinamide, an NADK inhibitor prodrug. Clin Cancer Res; 22(21); 5189–95. ©2016 AACR.

Dihydrofolate reductase (DHFR), because of its essential role in DNA synthesis, has been targeted for the treatment of a wide variety of human diseases, including cancer, autoimmune diseases, and infectious diseases. Methotrexate (MTX), a tight binding inhibitor of DHFR, is one of the most widely used drugs in cancer treatment and is especially effective in the treatment of acute lymphocytic leukemia, non-Hodgkin’s lymphoma, and osteosarcoma. Limitations to its use in cancer include natural resistance and acquired resistance due to decreased cellular uptake and decreased retention due to impaired polyglutamylate formation and toxicity at higher doses. Here, we describe a novel mechanism to induce DHFR degradation through cofactor depletion in neoplastic cells by inhibition of NAD kinase, the only enzyme responsible for generating NADP, which is rapidly converted to NADPH by dehydrogenases/reductases. We identified an inhibitor of NAD kinase, thionicotinamide adenine dinucleotide phosphate (NADPS), which led to accelerated degradation of DHFR and to inhibition of cancer cell growth. Of importance, combination treatment of NADPS with MTX displayed significant synergy in a metastatic colon cancer cell line and was effective in a MTX-transport resistant leukemic cell line. We suggest that NAD kinase is a valid target for further inhibitor development for cancer treatment.

As we enter the era of precision medicine, characterization of cancer genomes will directly influence therapeutic decisions in the clinic. Here we describe a platform enabling functionalization of rare gene mutations through their high-throughput construction, molecular barcoding and delivery to cancer models for in vivo tumour driver screens. We apply these technologies to identify oncogenic drivers of pancreatic ductal adenocarcinoma (PDAC). This approach reveals oncogenic activity for rare gene aberrations in genes including NAD Kinase (NADK), which regulates NADP(H) homeostasis and cellular redox state. We further validate mutant NADK, whose expression provides gain-of-function enzymatic activity leading to a reduction in cellular reactive oxygen species and tumorigenesis, and show that depletion of wild-type NADK in PDAC cell lines attenuates cancer cell growth in vitro and in vivo. These data indicate that annotating rare aberrations can reveal important cancer signalling pathways representing additional therapeutic targets., Next generation sequencing allows the identification of oncogenic driver genes in pancreatic cancer. Here, in an effort to identify additional causal genes, the authors develop a high throughput in vivo screen and identify genes that whilst infrequently mutated in pancreatic cancer contribute to tumour formation.

The purpose of the present work was to investigate the in vivo concentrations of sorbic acid and vanillin as markers of the fate of organic acids (OA) and natural identical flavors (NIF) from a microencapsulated mixture and from the same mixture non-microencapsulated, and the possible consequences on the intestinal microbial fermentation. Fifteen weaned pigs were selected from 3 dietary groups and were slaughtered at 29.5 +/- 0.27 kg of BW. Diets were (1) control; (2) control supplemented with a blend of OA and NIF microencapsulated with hydrogenated vegetable lipids (protected blend, PB); and (3) control supplemented with the same blend of OA and NIF mixed with the same protective matrix in powdered form but without the active ingredient coating (non-protected blend, NPB). Stomach, cranial jejunum, caudal jejunum, ileum, cecum, and colon were sampled to determine the concentrations of sorbic acid and vanillin contained in the blend and used as tracers. Sorbic acid and vanillin were not detectable in pigs fed the control, and their concentrations were not different in the stomach of PB and NPB treatments. Pigs fed PB showed a gradual decrease of the tracer concentrations along the intestinal tract, whereas pigs fed NPB showed a decline of tracer concentration in the cranial jejunum and onwards, compared with the stomach concentrations. Sorbic acid and vanillin concentrations along the intestinal tract were greater (P = 0.02) in pigs fed PB compared with pigs fed NPB. Pigs fed PB had lower (P = 0.03) coliforms in the caudal jejunum and the cecum than pigs fed the control or NPB. Pigs fed the control or PB had a greater (P = 0.03) lactic acid bacteria plate count in the cecum than pigs fed NPB, which showed a reduction (P = 0.02) of lactic acid concentrations and greater (P = 0.02) pH values in the caudal jejunum. The protective lipid matrix used for microencapsulation of the OA and NIF blend allowed slow-release of both active ingredients and prevented the immediate disappearance of such compounds upon exiting the stomach.

Rapidly proliferating tumors attempt to meet the demands for nucleotide biosynthesis by up-regulating folate pathways that provide the building blocks for pyrimidine and purine biosynthesis. Reduced folates are carriers of one carbon units required for the synthesis of purines, thymidylate and methionine, derived from serine, glycine and formate. As folate metabolism plays a key role in cell proliferation, the folate-requiring enzymes dihydrofolate reductase and thymidylate synthase have long been key targets for treatment of cancer. Recent studies show that the mitochondrial folate enzymes are also critical, in that they enable mitochondria to produce additional one carbon units for purine synthesis to allow for rapid growth. In transformed cells, methylene tetrahydrofolate dehydrogenase MTHFD2 is often reactivated and expressed along with other members of the serine synthesis, one carbon (folate) metabolism and glycine cleavage system, allowing for enhanced production of purines, ATP and NADPH, fueling cell proliferation [1]. More recently, it has been recognized that these enzymes are critical for the generation of NADH/NADPH, necessary for protection from ROS and required for macromolecular synthesis. MTHFD2 is a bifunctional enzyme with methylene dehydrogenase and cyclohydrolase activity that produces N-10 formyl tetrahydrofolate, the source of C2 and C8 in purines and NADH from methylenetetrahydrofolate and NAD [2]. The cytoplasmic enzyme, MTHFD1 uses NADP as a cofactor as compared to MTHFD2, which carries out the same enzyme activity using NAD, Mg++ and PO4-. In rapidly growing cancer cells, but not normal proliferating cells, MTHFD2 is the major source of formate for purine synthesis (Figure ​(Figure11). Figure 1 The cytoplasmic enzyme, MTHFD1, uses NADP as a cofactor as compared to MTHFD2, which carries out the same enzyme activity using NAD, Mg++ and PO4-. R= p-aminobenzoylglutamate Using gene expression arrays, we have shown that overexpression of mitochondrial enzymes, particularly MTHFD2, is associated with both high proliferation rates and cMYC overexpression [3]; this key role for MTHFD2 in cancer cell proliferation has recently been confirmed [4]. Most importantly, overexpression of MTHFD2 has been shown to be associated with poor prognosis of patients with breast cancer [5] and with an increased rate of invasion and metastasis [6]. That MTHFD2: 1) is over expressed in rapidly replicating tumor cells but not in adult tissue, and 2) enhances tumor cell proliferation provides a strong rationale for targeting this enzyme for selective cancer treatment [7]. The New Twist. It has recently been shown that MTHFD2 can have an impact on proliferation independent of its enzymatic activity [8]. In these studies, MTHFD2 was found in the nucleus, and co-localized with DNA replication sites. How this interaction enhances proliferation is unknown. That MTHFD2 has a dual effect on tumor cell proliferation, i.e., enhancing nucleotide synthesis directly and possibly “moonlighting” as a DNA binding protein [8] makes it an even more important and selective target for cancer treatment, but suggests that inhibition of enzyme activity alone may not be sufficient to effect tumor regression. If inhibition of this enzyme activity proves to be not effective, new approaches targeting transcription or translation may be required to achieve anti-tumor activity.

Introduction Postoperative delirium can be a serious consequence of major surgery, associated with longer hospital stays, readmission, cognitive and functional deterioration and mortality. Delirium is an acute, reversible disorder characterised by fluctuating course, inattention, disorganised thinking and altered level of consciousness. Delirium occurring in the hours immediately following anaesthesia and delirium occurring in the postoperative period of 1–5 days have been described as distinct clinical entities. This protocol describes an observational study with the aim of determining if delirium in the first hour following tracheal tube removal is a predictor of delirium in the 5 subsequent postoperative days. Improved understanding regarding the development of postoperative delirium would improve patient care and allow more effective implementation of delirium prevention measures. Methods and analysis Patients enrolled to the Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) randomised controlled trial will be eligible for this substudy. A validated delirium assessment method, the 3-min Diagnostic Confusion Assessment Method and the Richmond Agitation and Sedation Scale will be used to assess 100 patients for delirium at 30 min and 60 min following tracheal tube removal. Patients will also be assessed for delirium over postoperative days 1–5 using three validated methods, the Confusion Assessment Method (CAM), CAM for the Intensive Care Unit and structured chart review. Logistic regression analysis will then be performed to test whether immediately postoperative delirium independently predicts subsequent postoperative delirium. Ethics and dissemination This observational substudy of ENGAGES has been approved by the ethics board of Washington University School of Medicine. Enrolment began in June 2016 and will continue until June 2017. Dissemination plans include presentations at scientific conferences and scientific publications. Trial registration number NCT02241655.

NAD(+) kinase (NADK) is the only known cytosolic enzyme that converts NAD(+) to NADP(+), which is subsequently reduced to NADPH. The demand for NADPH in cancer cells is elevated as reducing equivalents are required for the high levels of nucleotide, protein, and fatty acid synthesis found in proliferating cells as well as for neutralizing high levels of reactive oxygen species (ROS). We determined whether inhibition of NADK activity is a valid anticancer strategy alone and in combination with chemotherapeutic drugs known to induce ROS. In vitro and in vivo inhibition of NADK with either small-hairpin RNA or thionicotinamide inhibited proliferation. Thionicotinamide enhanced the ROS produced by several chemotherapeutic drugs and produced synergistic cell kill. NADK inhibitors alone or in combination with drugs that increase ROS-mediated stress may represent an efficacious antitumor combination and should be explored further.

Previous studies have documented the roles of transport via the reduced folate carrier, retention via polyglutamylation, and increased levels of the target enzyme, dihydrofolate reductase in sensitivity to methotrexate. Recent studies have shown that the mitochondrial enzymes in the cellular metabolism of serine, folate, and glycine are overexpressed in a subset of human cancers and that their expression is required for tumor maintenance. In this Perspective article, we propose that the expression of mitochondrial enzymes in the metabolism of serine and glycine, in addition to those involved in folate metabolism, are determinants of the response to methotrexate. Furthermore, we show that myc activation in tumors is associated with upregulation of these enzymes. We propose that patients whose tumors show this phenotype will be sensitive to folate antagonists targeting thymidylate or purine biosynthesis. Cancer Res; 73(2); 478–82. ©2012 AACR.

Next generation sequencing (NGS) technologies are rapidly being incorporated into the clinic to facilitate decisions on cancer patient care. However, successful translation of NGS data requires knowledge on which DNA aberrations represent actionable events, either for development or re-positioning of approved agents to target their activated pathways. Recognizing this, large-scale tumor profiling efforts by consortia such as The Cancer Genome Atlas (TCGA) are cataloging genomic aberrations across major cancer lineages. These efforts have revealed an extraordinary level of genome complexity made up of not only key “driver” events critical to pathogenesis, but also numerous biologically-neutral “passengers” that accompany unstable tumor genomes. The challenge now is to find ways to identify functional driver aberrations, as targeting such events or their activated pathways has great potential for improving patient outcomes. To do this, we have developed high-throughput approaches to construct molecularly-barcoded versions of gene aberrations for functional screens. Specifically, we developed technologies that include (1) high-throughput, accurate modeling of somatic DNA mutations (somatic missense mutations and small insertions/deletions) using our robotics-driven platform of >35,000 sequenced-verified open reading frame (ORF) clones, (2) a molecular barcoding strategy that permits rapid DNA tagging of wild-type and mutant ORFs, (3) multi-fragment recombineering methodologies allowing construction of cancer fusion genes, and (4) combining the use of these reagents for individual or pooled functional screens in vitro and in vivo using human and mouse systems. We are using these technologies, which are widely applicable to all cancer types, to identify the highest priority targets to enroll in deep mechanistic studies and drug discovery programs. We have scaled our pipelines to functionalize thousands of cancer gene aberrations. Importantly, we are now constructing entire somatically-mutated exomes from individual patients sequenced in the clinic. As an example of our “Personalized Functionalization” approach, we screened individual pancreatic ductal adenocarcinoma (PDAC) patient-derived aberration libraries for mutations capable of promoting tumorigenesis in vivo using a mouse xenograft model engineered with regulatable KRASG12D, an oncogene active in the majority of PDAC patient tumors. These studies revealed potent aberration drivers that are active as individual drivers as well as those that are contextual and are only active in the presence of KRASG12D. Based on these results, we have chosen NAD Kinase (NADK) for deep mechanistic studies and drug discovery programs. NADK catalyzes the conversion of cytoplasmic NAD+ to NADP+/NADPH and thus aids other modes of cellular NADPH production. Our validation studies indicate that the NADK mutation results in robust gain-of-function kinase activity leading to its hyper-phosphorylation of NAD+ accompanied by reduced accumulation or reactive oxygen species and increased tumor formation and growth. Interestingly, recent work by others report other mechanisms by which KRAS rewires PDAC tumors to maximize energy production and promote NADPH accumulation to maintain redox state and tumor growth. Even though NADK is mutated at low frequency in PDAC, its selection demonstrates that the discovery of rare, functional aberrations may intersect or otherwise lead us to important pathways and potential therapeutic liabilities. Our ultimate goal is to functionally annotate thousands of somatic aberrations in cancer, the vast majority of which have not been previously recognized or assayed for clinical relevance. These systems will reveal high priority edited targets to enroll in deep mechanistic biology studies, drug discovery and development programs ultimately leading to personalized treatment strategies. Citation Format: Kenneth Scott, Yiu Huen Tsang, Turgut Dogruluk, Philip Tedeschi, Joseph Bertino, Gordon Mills. Functional prioritization of rare gene aberration drivers of cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr PR06.

BACKGROUND. Prostatic small cell carcinoma is increasing in frequency in patients resistant to all forms of androgen ablation. It is a high-grade malignant neoplasm with neuroendocrine features. There are no suitable cellular models to study this particular type of carcinoma. A recent study showed that the PC-3 cell line has neuroendocrine characteristics (1). This report prompted us to determine if this cell line is enriched in tumor initiating cells, and to use this cell line as a model to determine sensitivity to second generation anti androgen treatments and chemotherapeutic agents. METHODS. To determine the percentage of tumor initiating cells (TICs) marker expression comparing LNCaP with PC-3 cells, flow cytometry analysis was used. Functional assays such as migration, invasion, colony formation and sphere formation were used to determine metastatic potential. Secondary and tertiary spheroid assays were used to determine the self-renewal ability. The CellTiter 96® AQueous non-radioactive cell proliferation assay was used to identify response to hormone deprivation and chemotherapeutic drugs. RESULTS. The growth rate of PC-3 was similar to LNCaP cells while the TIC marker CD44 was only expressed on PC-3 cells. Both LNCaP and PC-3 cells expressed α2β1 with the highest expression detected in PC-3 cells. No expression of CD133 was detected in either of the cell lines. PC-3, as compared to LNCaP cells, displayed an increase in 5-minute collagen-I attachment, cell migration, invasion, colony formation and sphere formation in an anchorage-independent environment. PC-3 cells were capable of self-renewal in the secondary and tertiary spheroid assays and expressed neuroendocrine markers such as chromogranin A and EMT marker, Twist. PC-3 cells were able to also grow in androgen-deprived media, and as compared to LNCaP cells, demonstrated resistance to anti-androgen drugs that included enzalutamide and abiraterone and chemotherapy drugs such as doxorubicin and taxotere. Surprisingly, PC-3 cells were more sensitive to methotrexate than LNCaP or DU145 cells. PC3 cells had lower levels of MTAP (methylthioadenosine phosphorylase) and hence may be the reason for their sensitivity to denovo purine synthesis inhibitors such as methotrexate. CONCLUSIONS. The novel findings presented here provide evidence that castrate resistant PC-3 cells are CD44+/ α2β1+/CD24low/CD133_ and possess stem cell properties and may serve as a useful model to study the role of new treatments for prostate cancer with neuroendocrine features. Reference: 1) Prostate. 2011 Nov; 71(15): 1668-79; PC3 is a cell line characteristic of prostatic small cell carcinoma; Tai S, Sun Y, Squires JM, Zhang H, Oh WK, Liang CZ, Huang J Citation Format: Nitu Bansal, Lisa Wu, Nadine Johnson Farley, Philip Tedeschi, Joseph R. Bertino. The castrate resistant PC-3 cell line with neuroendocrine features is enriched in tumor initiating cells and is resistant to enzalutamide and abiraterone but sensitive to antimetabolites. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4208. doi:10.1158/1538-7445.AM2015-4208

In T-cell acute lymphoblastic leukemia (ALL), the genes CDKN2A (p16 and p14) and MTAP are homozygously co-deleted, with a frequency of ∼35 %. MTAP cleaves the natural substrate, 5′-deoxy-5′-methylthioadenosine, to adenine and 5-methylthioribose-1-phosphate, which are converted to adenine nucleotides and methionine. Cells lacking MTAP are unable to salvage adenine through this pathway and rely on the de novo pathway for purine synthesis. This variation between normal MTAP+ cells and tumor MTAP-/- cells led to several studies showing that MTAP -/- cells are more sensitive to inhibitors of de novo purine synthesis. Pralatrexate (PDX) is a second generation antifolate that targets dihydrofolate reductase and via conversion to polyglutamylates, inhibits de novo purine synthesis. 6-Thioguanine (6TG), an antimetabolite analog of guanine, also target de novo purine synthesis. MTAP-deficient ALL cells should be more sensitive to these agents, remarkably so in combination. We tested single agent PDX and 6TG as well as a combination treatment in MTAP+ (Molt4) and MTAP-/- (CEM) ALL xenografts. CEM xenografts were more sensitive to PDX treatment than MOLT4 xenografts. CEM xenografts were also much more sensitive to 6TG, while Molt4 xenografts were resistant to 6TG. Early results of the combination of PDX and 6TG in vivo show promise as an effective therapy of MTAP-/- T-cell ALL. Citation Format: Philip M. Tedeschi, Yamini K. Kathari, Iqra Farooqi, Joseph R. Bertino. Methylthioadenosine phosphorylase (MTAP)-deficient T-cell ALL xenografts are sensitive to pralatrexate and 6-thioguanine alone and in combination. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 843. doi:10.1158/1538-7445.AM2014-843

Background: Recent observations on cancer cell metabolism indicate increased serine synthesis from glucose as a marker of poor prognosis. Expression of genes in this pathway also correlate with sensitivity to the antifolate methotrexate (Vazquez A, et al, Cancer Res. 2013 Jan 15;73(2):478-82). Using a large-scale model of human cell metabolism we have predicted that serine synthesis can be routed to a pathway for ATP production. The pathway is composed by reactions from the serine synthesis, one carbon (folate) metabolism and the glycine cleavage system (SOG pathway) and its flux is predicted to increase at high proliferation rates. Results: Here we show that the SOG pathway is upregulated at the level of gene expression in a subset of human tumors and its level of expression correlates with gene signatures of cell proliferation and Myc targets activation. To investigate the activity of the SOG pathway at the level of metabolic fluxes we estimated the metabolic fluxes of the NCI60 panel of tumor derived cell lines, using previously reported exchange fluxes and a flux balance model of cell metabolism. We show that the estimated rates of reactions in the SOG pathway are highly correlated with the proliferation rates of these cell lines. We also find that the SOG pathway contributes significantly to the energy requirements of biosynthesis, the NADPH requirements of fatty acid synthesis and to the synthesis of purines. Finally, when the PC-3 prostate cancer cell line is subject to treatment with the antifolate methotrexate, we observe a decrease in the ATP levels, an inhibition of the proliferation rate and a decrease in the ribonucleotides and fatty acids synthesized from glucose. Conclusions: Taken together our results indicate that the SOG pathway activity increases with the rate of cell proliferation and it contributes to the biosynthetic requirements of purines, ATP and NADPH. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C151. Citation Format: Philip M. Tedeschi, Elke K. Markert, Murugesan Gounder, HongXia Lin, Sonia C. Dolfi, Leo Li-Ying Chan, Jean Qiu, Kim M. Hirshfield, Laszlo G. Boros, Joseph R. Bertino, Zoltan N. Oltvai, Alexei Vazquez. Contribution of serine, folate, and glycine metabolism to the ATP, NADPH, and purine requirements of cancer cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C151.

Recent observations on cancer cell metabolism indicate increased serine synthesis from glucose as a marker of poor prognosis. We have predicted that a fraction of the synthesized serine is routed to a pathway for ATP production. The pathway is composed by reactions from serine synthesis, one-carbon (folate) metabolism and the glycine cleavage system (SOG pathway). Here we show that the SOG pathway is upregulated at the level of gene expression in a subset of human tumors and that its level of expression correlates with gene signatures of cell proliferation and Myc target activation. We have also estimated the SOG pathway metabolic flux in the NCI60 tumor-derived cell lines, using previously reported exchange fluxes and a personalized model of cell metabolism. We find that the estimated rates of reactions in the SOG pathway are highly correlated with the proliferation rates of these cell lines. We also observe that the SOG pathway contributes significantly to the energy requirements of biosynthesis, to the NADPH requirement for fatty acid synthesis and to the synthesis of purines. Finally, when the PC-3 prostate cancer cell line is treated with the antifolate methotrexate, we observe a decrease in the ATP levels, AMP kinase activation and a decrease in ribonucleotides and fatty acids synthesized from [1,2-(13)C2]-D-glucose as the single tracer. Taken together our results indicate that the SOG pathway activity increases with the rate of cell proliferation and it contributes to the biosynthetic requirements of purines, ATP and NADPH of cancer cells.

Background Although cells require nutrients to proliferate, most nutrient exchange rates of the NCI60 panel of cancer cell lines correlate poorly with their proliferation rate. Here, we provide evidence indicating that this inconsistency is rooted in the variability of cell size. Results We integrate previously reported data characterizing genome copy number variations, gene expression, protein expression and exchange fluxes with our own measurements of cell size and protein content in the NCI60 panel of cell lines. We show that protein content, DNA content, and protein synthesis per cell are proportional to the cell volume, and that larger cells proliferate slower than smaller cells. We estimate the metabolic fluxes of these cell lines and show that their magnitudes are proportional to their protein synthesis rate and, after correcting for cell volume, to their proliferation rate. At the level of gene expression, we observe that genes expressed at higher levels in smaller cells are enriched for genes involved in cell cycle, while genes expressed at higher levels in large cells are enriched for genes expressed in mesenchymal cells. The latter finding is further corroborated by the induction of those same genes following treatment with TGFβ, and the high vimentin but low E-cadherin protein levels in the larger cells. We also find that aromatase inhibitors, statins and mTOR inhibitors preferentially inhibit the in vitro growth of cancer cells with high protein synthesis rates per cell. Conclusions The NCI60 cell lines display various metabolic activities, and the type of metabolic activity that they possess correlates with their cell volume and protein content. In addition to cell proliferation, cell volume and/or biomarkers of protein synthesis may predict response to drugs targeting cancer metabolism.

Background Alterations in cell proliferation and tissue remodeling are major hallmarks of cancer. Given that these two physiological processes require a significant investment of metabolic resources, we hypothesize that the metabolism of cancer cells is, in a first approximation, determined by the magnitude of cell proliferation and tissue remodeling. Materials and methods To address this question in further detail we have analyzed in vitro data characterizing cancer cell lines and gene expression profiles of human cancers. Results We show that the metabolism of cancer cells is strongly correlated with cell proliferation and tissue remodeling. Based on in vitro data, cancer cell lines align from an extreme of highly proliferating cells of relatively small size to another extreme of slowly proliferating cells with large size and mesenchymal properties [1]. Similarly, in human cancers we detect a strong negative correlation between gene signatures associated with cell proliferation and tissue remodeling [2]. The stratification of human cancers based on the cell-proliferation/ tissue-remodeling signatures results in divergence in the survival plots as significant as those obtained using current site-specific classifications. Furthermore, in vitro data suggest that these different subtypes have a differential sensitivity to diverse drug classes targeting metabolism [1]. Conclusions We conclude that human cancers can be subject to a universal cell-proliferation/tissue-remodeling classification independent of their site of origin that can guide personalized treatment targeting cancer metabolism.

Maintenance of phytoplasma strains in tissue culture is achievable for all strains transmitted to periwinkle (Catharanthus roseus), and also for other naturally infected plant host species. Shoots of 1–3 cm length are grown in a solid medium containing Murashige and Skoog (MS) micro- and macroelements and 0.12 mg/L benzylaminopurine. The continued presence of phytoplasmas in infected shoots of periwinkle that have been maintained in micropropagation for up to 20 years can be shown by diagnostic methods such as nested PCR tests using the 16S rDNA gene (see Chapters 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, and 26 for phytoplasma diagnostic methods).