PRMT1 Sustains De Novo Fatty Acid Synthesis by Methylating PHGDH to Drive Chemoresistance in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) chemoresistance hampers the ability to effectively treat patients. Identification of mechanisms driving chemoresistance can lead to strategies to improve treatment. Here, we revealed that protein arginine methyltransferase-1 (PRMT1) simultaneously methylates D-3-phosphoglycerate dehydrogenase (PHGDH), a critical enzyme in serine synthesis, and the glycolytic enzymes PFKFB3 and PKM2 in TNBC cells. 13C metabolic flux analyses showed that PRMT1-dependent methylation of these three enzymes diverts glucose toward intermediates in the serine-synthesizing and serine/glycine cleavage pathways, thereby accelerating the production of methyl donors in TNBC cells. Mechanistically, PRMT1-dependent methylation of PHGDH at R54 or R20 activated its enzymatic activity by stabilizing 3-phosphoglycerate binding and suppressing polyubiquitination. PRMT1-mediated PHGDH methylation drove chemoresistance independently of glutathione synthesis. Rather, activation of the serine synthesis pathway supplied α-ketoglutarate and citrate to increase palmitate levels through activation of fatty acid synthase (FASN). Increased palmitate induced protein S-palmitoylation of PHGDH and FASN to further enhance fatty acid synthesis in a PRMT1-dependent manner. Loss of PRMT1 or pharmacologic inhibition of FASN or protein S-palmitoyltransferase reversed chemoresistance in TNBC. Furthermore, IHC coupled with imaging MS in clinical TNBC specimens substantiated that PRMT1-mediated methylation of PHGDH, PFKFB3, and PKM2 correlates with chemoresistance and that metabolites required for methylation and fatty acid synthesis are enriched in TNBC. Together, these results suggest that enhanced de novo fatty acid synthesis mediated by coordinated protein arginine methylation and protein S-palmitoylation is a therapeutic target for overcoming chemoresistance in TNBC. SIGNIFICANCE: PRMT1 promotes chemoresistance in TNBC by methylating metabolic enzymes PFKFB3, PKM2, and PHGDH to augment de novo fatty acid synthesis, indicating that targeting this axis is a potential treatment strategy.

IDH2 stabilizes HIF-1α-induced metabolic reprogramming and promotes chemoresistance in urothelial cancer.

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine-resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain-of-function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif-1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine-resistant UC cells. Interestingly, IDH2-mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2-mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo-resistant urothelial carcinoma.

Comprehensive geriatric assessment as a useful tool in predicting adverse events in elderly patients with diffuse large B-cell lymphoma.

We conducted a multicenter prospective study on whether a comprehensive geriatric assessment (CGA) can predict the adverse events (AEs) of chemotherapy in elderly patients with diffuse large B-cell lymphoma (DLBCL). Patients aged ≥ 65 years with newly diagnosed DLBCL underwent a pretreatment baseline CGA consisting of six assessment tools: activities of daily living (ADL), instrumental ADL (IADL), mood, nutritional status, comorbidities, and cognitive function. An attending physician chose each patient's treatment but was blind to CGA results. Patients were grouped as "dependent" or "independent" according to the CGA. The primary endpoint was to evaluate the association between chemotherapy-induced grade 3-4 toxicity and CGA. Of 86 patients, 78 completed the designated CGA. The median age was 79 years (65-89). Seventy-two patients were treated with a cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP-like) regimen, and six were treated with low-toxicity regimens. Forty-one patients were classified as dependent and 37 as independent. In multivariate analysis, an impairment of IADL was independently associated with grade 3-4 leukopenia (odds ratio [OR] 0.63; 95% confidence interval [CI] 0.43-0.92, p = 0.017) and anemia (OR 0.67; 95% CI 0.50-0.90, p = 0.008). The presence of a comorbidity was also associated with grade 3-4 non-hematological toxicity (OR 2.17; 95% CI 1.37-3.43, p = 0.001). The 4-year survival rate tended to be longer in the independent (72.7%) compared to dependent (56.9%) group. Overall, a CGA may be a useful tool for predicting serious AEs associated with chemotherapy in elderly patients with DLBCL.

The hypotaurine-taurine pathway as an antioxidative mechanism in patients with acute liver failure.

The liver has been thought to protect against oxidative stress through mechanisms involving reduced glutathione (GSH) that consumes high-energy phosphor-nucleotides on its synthesis. However, hepatoprotective mechanisms in acute liver failure (ALF) where the phosphor-nucleotides are decreased in remain to be solved. Liver tissues were collected from patients with ALF and liver cirrhosis (LC) and living donors (HD) who had undergone liver transplantation. Tissues were used for metabolomic analyses to determine metabolites belonging to the central carbon metabolism, and to determine sulfur-containing metabolites. ALF and LC exhibited a significant decline in metabolites of glycolysis and pentose phosphate pathways and high-energy phosphor-nucleotides such as adenosine triphosphate as compared with HD. Conversely, methionine, S-adenosyl-l-methionine, and the ratio of serine to 3-phosphoglycerate were elevated significantly in ALF as compared with LC and HD, suggesting a metabolic boost from glycolysis towards trans-sulfuration. Notably in ALF, the increases in hypotaurine (HTU) + taurine (TU) coincided with decreases in the total amounts of reduced and oxidized glutathione (GSH + 2GSSG). Plasma NH3 levels correlated with the ratio of HTU + TU to GSH + 2GSSG. Increased tissue levels of HTU + TU vs total glutathione appear to serve as a biomarker correlating with hyperammonemia, suggesting putative roles of the HTU-TU pathway in anti-oxidative protective mechanisms.

Airway hyperresponsiveness and inflammation in Japanese patients with human immunodeficiency virus 1 infection.

INTRODUCTION: Despite the growing population of long-term survivors with human immunodeficiency virus 1 (HIV) exhibiting asthma-like features worldwide, the pathogenesis underlying airway hyperresponsiveness (AHR) and airway inflammation remains unclear. We aimed to investigate AHR and airway inflammation in an HIV-infected Japanese population. METHODS: Of 94 Japanese participants, 10 HIV-infected participants with asthma were excluded from the study. We compared the characteristics of HIV-infected (n = 34) and non-HIV-infected participants (n = 50). Eosinophilic, neutrophilic, mixed (eosinophilic and neutrophilic), and paucigranulocytic airway inflammatory phenotypes were classified based on induced sputum characteristics. RESULTS: The prevalence of AHR in HIV-infected participants (32.4%) was significantly higher than that in their non-HIV-infected counterparts (10.0%) (P = 0.0213). The multivariate nominal logistic regression analysis revealed HIV as an independent risk factor for AHR. HIV-infected participants were significantly more likely to have a neutrophilic airway inflammatory phenotype than non-HIV-infected participants (P = 0.0358). Furthermore, HIV-infected participants with AHR demonstrated a significant correlation between AHR levels and the percentage of sputum neutrophils (r = -0.65, P = 0.0316). The percentage of sputum neutrophils was negatively associated with the blood CD4 cell count (r = -0.66, P = 0.0266). CONCLUSIONS: We observed the high prevalence of AHR and neutrophilic airway inflammatory phenotype in Japanese participants with stable HIV infection. Our findings provide insight into the mechanisms of AHR and may facilitate the development of novel treatment for individuals with AHR and HIV infection.

On-tissue polysulfide visualization by surface-enhanced Raman spectroscopy benefits patients with ovarian cancer to predict post-operative chemosensitivity.

Chemosensitivity to cisplatin derivatives varies among individual patients with intractable malignancies including ovarian cancer, while how to unlock the resistance remain unknown. Ovarian cancer tissues were collected the debulking surgery in discovery- (n = 135) and validation- (n = 47) cohorts, to be analyzed with high-throughput automated immunohistochemistry which identified cystathionine γ-lyase (CSE) as an independent marker distinguishing non-responders from responders to post-operative platinum-based chemotherapy. We aimed to identify CSE-derived metabolites responsible for chemoresistant mechanisms: gold-nanoparticle (AuN)-based surface-enhanced Raman spectroscopy (SERS) was used to enhance electromagnetic fields which enabled to visualize multiple sulfur-containing metabolites through detecting scattering light from Au-S vibration two-dimensionally. Clear cell carcinoma (CCC) who turned out less sensitive to cisplatin than serous adenocarcinoma was classified into two groups by the intensities of SERS intensities at 480 cm-1; patients with greater intensities displayed the shorter overall survival after the debulking surgery. The SERS signals were eliminated by topically applied monobromobimane that breaks sulfane-sulfur bonds of polysulfides to result in formation of sulfodibimane which was detected at 580 cm-1, manifesting the presence of polysulfides in cancer tissues. CCC-derived cancer cell lines in culture were resistant against cisplatin, but treatment with ambroxol, an expectorant degrading polysulfides, renders the cells CDDP-susceptible. Co-administration of ambroxol with cisplatin significantly suppressed growth of cancer xenografts in nude mice. Furthermore, polysulfides, but neither glutathione nor hypotaurine, attenuated cisplatin-induced disturbance of DNA supercoiling. Polysulfide detection by on-tissue SERS thus enables to predict prognosis of cisplatin-based chemotherapy. The current findings suggest polysulfide degradation as a stratagem unlocking cisplatin chemoresistance.

2-Nitroimidazoles induce mitochondrial stress and ferroptosis in glioma stem cells residing in a hypoxic niche.

Under hypoxic conditions, nitroimidazoles can replace oxygen as electron acceptors, thereby enhancing the effects of radiation on malignant cells. These compounds also accumulate in hypoxic cells, where they can act as cytotoxins or imaging agents. However, whether these effects apply to cancer stem cells has not been sufficiently explored. Here we show that the 2-nitroimidazole doranidazole potentiates radiation-induced DNA damage in hypoxic glioma stem cells (GSCs) and confers a significant survival benefit in mice harboring GSC-derived tumors in radiotherapy settings. Furthermore, doranidazole and misonidazole, but not metronidazole, manifested radiation-independent cytotoxicity for hypoxic GSCs that was mediated by ferroptosis induced partially through blockade of mitochondrial complexes I and II and resultant metabolic alterations in oxidative stress responses. Doranidazole also limited the growth of GSC-derived subcutaneous tumors and that of tumors in orthotopic brain slices. Our results thus reveal the theranostic potential of 2-nitroimidazoles as ferroptosis inducers that enable targeting GSCs in their hypoxic niche.

Predictive value of CD73 expression for the efficacy of immune checkpoint inhibitors in NSCLC.

BACKGROUND: CD73 induces the dephosphorylation of adenosine monophosphate converting it to adenosine, enabling malignancies to escape from immune surveillance. Although CD73 overexpression has been reported to be a poor prognostic factor in several malignancies including non-small cell lung cancer (NSCLC), its predictive relevance in NSCLC patients receiving immune checkpoint inhibitors is unknown. The present research was conducted to investigate the prognostic significance of CD73 expression in NSCLC patients receiving immune checkpoint inhibitors (ICIs). METHODS: We screened 91 patients with advanced or recurrent NSCLC who received immune checkpoint inhibitors. CD73 expression was evaluated immunohistochemically using tissue specimens obtained just before treatment with ICIs. RESULTS: Analysis of progression-free survival (PFS) and overall survival (OS) in relation to several levels of CD73 expression (1%, 10%, 30%, and 50%) showed that both tended to be more favorable as expression of CD73 increased. PFS and OS were longer for patients in whom at least 50% of the tumor cells expressed CD73 than for those in whom <50% of the tumor cells did so. In patients who were positive for EGFR mutation, immune checkpoint inhibitors were significantly more effective in those with high CD73 expression, whereas CD73 expression did not significantly affect the efficacy in patients with EGFR mutation-negative NSCLC. Furthermore, CD73 expression was predictive factor for the PFS independent of PD-L1 expression in patients with EGFR mutation. CONCLUSIONS: High CD73 expression may predict a favorable response to ICIs in NSCLC patients, especially those harboring EGFR mutations. KEY POINTS: Significant findings of the study: In patients who were positive for EGFR mutation, immune checkpoint inhibitors (ICIs) were significantly more effective in those with high CD73 expression, whereas CD73 expression did not significantly affect the efficacy in patients with EGFR mutation-negative NSCLC. WHAT THIS STUDY ADDS: High CD73 expression may predict a favorable response to immune checkpoint inhibitors in NSCLC patients, especially those harboring EGFR mutations.

Determination of Somatic Mutations and Tumor Mutation Burden in Plasma by CAPP-Seq during Afatinib Treatment in NSCLC Patients Resistance to Osimertinib.

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) were developed to target the EGFR T790M resistance mutation in non-small cell lung cancer (NSCLC) patients resistant to first- or second-generation EGFR-TKIs. To investigate the efficacy of afatinib treatment for EGFR T790M-positive NSCLC patients showing resistance to osimertinib and alterations in somatic mutations and tumor mutation burden (TMB) in plasma circulating tumor DNA (ctDNA) during afatinib treatment, we conducted a prospective study using Cancer Personalized Profiling by deep Sequencing (CAPP-Seq). Nine NSCLC patients with EGFR T790M mutation who showed resistance to third-generation EGFR-TKIs were enrolled in this study and treated with afatinib. Plasma samples were collected before treatment, 4 weeks after treatment, and at disease progression. The mutation profile and TMB in plasma ctDNA were analyzed by CAPP-Seq. The objective response rate and median progression-free survival associated with afatinib were 0% and 2.0 months, respectively. The C797S mutation-mediated resistance to osimertinib was observed in one patient and following afatinib treatment in two patients; the C797S mutations occurred in the same allele as the T790M mutation. After afatinib treatment, afatinib-sensitive mutant alleles, such as ERBB2, and TMB decreased. We have demonstrated that detection of mutant allele frequency and TMB of ctDNA by CAPP-Seq could help determine the effectiveness of and resistance to afatinib. Although afatinib monotherapy for T790M-positive NSCLC resistant to osimertinib was less effective, the action for multiclonal mutant alleles and TMB might contribute to further treatment strategy.

Prognostic Value of Serum Tumor Markers in Patients With Stage III NSCLC Treated With Chemoradiotherapy.

BACKGROUND/AIM: Serum tumor markers such as carcinoembryonic antigen and cytokeratin subunit 19 fragment are generally monitored in non-small cell lung cancer (NSCLC) patients in the clinical practice. However, their clinical relevance in stage III NSCLC treated with concurrent chemoradiotherapy (CCRT) remains unclear. Herein, we examined the clinical relevance of tumor markers in those patients. PATIENTS AND METHODS: We retrospectively reviewed 62 consecutive patients with stage III NSCLC who received CCRT. We examined the associations of tumor marker levels with their prognosis. RESULTS: There was no correlation between pretreatment tumor marker levels and prognosis. Normal tumor marker levels post-CCRT were significantly associated with favorable progression-free survival (54.8 versus 14.5 months, p=0.02) and overall survival (71.7 versus 40.4 months, p=0.06) compared with high tumor marker levels post-CCRT. CONCLUSION: We revealed that normal tumor markers levels post-CCRT in stage III NSCLC might be a useful surrogate marker for curing those patients.

Biochemical, Metabolomic, and Genetic Analyses of Dephospho Coenzyme A Kinase Involved in Coenzyme A Biosynthesis in the Human Enteric Parasite Entamoeba histolytica.

Coenzyme A (CoA) is an essential cofactor for numerous cellular reactions in all living organisms. In the protozoan parasite Entamoeba histolytica, CoA is synthesized in a pathway consisting of four enzymes with dephospho-CoA kinase (DPCK) catalyzing the last step. However, the metabolic and physiological roles of E. histolytica DPCK remain elusive. In this study, we took biochemical, reverse genetic, and metabolomic approaches to elucidate role of DPCK in E. histolytica. The E. histolytica genome encodes two DPCK isotypes (EhDPCK1 and EhDPCK2). Epigenetic gene silencing of Ehdpck1 and Ehdpck2 caused significant reduction of DPCK activity, intracellular CoA concentrations, and also led to growth retardation in vitro, suggesting importance of DPCK for CoA synthesis and proliferation. Furthermore, metabolomic analysis showed that suppression of Ehdpck gene expression also caused decrease in the level of acetyl-CoA, and metabolites involved in amino acid, glycogen, hexosamine, nucleic acid metabolisms, chitin, and polyamine biosynthesis. The kinetic properties of E. histolytica and human DPCK showed remarkable differences, e.g., the Km values of E. histolytica and human DPCK were 58-114 and 5.2 µM toward dephospho-CoA and 15-20 and 192 µM for ATP, respectively. Phylogenetic analysis also supported the uniqueness of the amebic enzyme compared to the human counterpart. These biochemical, evolutionary features, and physiological importance of EhDPCKs indicate that EhDPCK represents the rational target for the development of anti-amebic agents.

Phase II Trial of Carboplatin and Pemetrexed Plus Bevacizumab with Maintenance Bevacizumab as a First-line Treatment for Advanced Non-squamous Non-small Cell Lung Cancer in Elderly Patients.

BACKGROUND/AIM: The combination of platinum-doublet chemotherapy with bevacizumab has been established as a first-line treatment option in non-elderly patients with non-squamous (non-sq) non-small cell lung cancer (NSCLC). However, the safety and efficacy of this regimen have not yet been fully established in elderly patients. PATIENTS AND METHODS: Chemo-naïve patients with non-sq NSCLC, aged ≥75 years, having a good performance status (Eastern Cooperative Oncology Group performance status 0-1) and adequate organ function were considered eligible. Patients received carboplatin (area under the curve=5 mg/ml/min), pemetrexed (500 mg/m2), and bevacizumab (15 mg/kg) every 3 weeks for up to 4 cycles, followed by maintenance bevacizumab. The primary endpoint was the objective response rate (ORR; target=50%, threshold=30%; Simon's two-stage design), and the secondary endpoints were safety, progression-free survival (PFS), and overall survival (OS). RESULTS: Twelve patients were enrolled from June 2013 to July 2017. The study was closed because of slow patient accrual. The median patient age was 80 years. Eleven patients (92%) completed 4 cycles of induction chemotherapy. Seven patients achieved a partial response (PR), yielding an ORR of 58%. The median PFS was 8.4 [95% confidence interval (CI)=4.4-10.5] months, and the median OS was 33.9 (95%CI=13.2-43.3) months. Toxicities were generally mild and consistent with previous reports. There were no treatment-related deaths. CONCLUSION: A regimen comprising carboplatin and pemetrexed plus bevacizumab followed by maintenance bevacizumab is feasible and potentially efficacious in elderly patients with non-sq NSCLC.

Pulmonary pleomorphic carcinoma: A case harboring EGFR mutation treated with EGFR-TKIs.

Pulmonary pleomorphic carcinoma (PPC) is a very rare type of primary lung cancer with an aggressive clinical course. Few reports have documented therapeutic options for PPC with EGFR mutations. Herein, we report a case of PPC with EGFR mutation treated with EGFR-tyrosine kinase inhibitors (TKIs). A 65-year-old Japanese woman was diagnosed with stage IV lung adenocarcinoma with L858R point mutation in exon 21. Despite treatment with erlotinib, the patient died after two weeks as a result of rapid disease progression. Postmortem examination indicated that the thoracic tumors consisted primarily of spindle/sarcomatous components, while expression of the mutated EGFR protein was only observed in adenocarcinoma components. We speculate that the tumor was not driven by EGFR mutation. Clinicians should bear in mind the possibility of pleomorphic carcinoma if EGFR-TKI treatment fails to achieve a clinical response for adenocarcinoma harboring an activating EGFR mutation diagnosed on the basis of small biopsy specimens.

Rechallenge treatment with a platinum-based regimen in patients with sensitive relapsed small-cell lung cancer.

Among patients with relapsed small-cell lung cancer (SCLC), those who relapse > 90 days after first-line chemotherapy are classified sensitive relapse. Rechallenge with a first-line platinum-based regimen has been used in sensitive relapsed SCLC patients, but its importance is not known. We evaluated the outcome of rechallenge with platinum-based chemotherapy for sensitive relapse patients. We reviewed consecutive patients with sensitive relapsed SCLC who received second-line chemotherapy between January 1999 and December 2016. We evaluated the treatment outcomes of platinum-based rechallenge and non-rechallenge regimens for second-line chemotherapy in sensitive relapse patients. Of 245 patients, 81 sensitive relapse patients received second-line chemotherapy. Sixty-seven patients (82.7%) were treated with rechallenging platinum-based regimens ("rechallenge group") and 14 patients (17.3%) were treated with other regimens ("non-rechallenge group") as second-line chemotherapy. Median progression-free survival (PFS) was 5.1 months in the rechallenge group and 3.5 months in the non-rechallenge group, and median survival time was 10.8 and 8.2 months, respectively. There were no significant differences in PFS or overall survival (OS) between the two groups. Sub-analyses of patients who received chemotherapy alone as first-line treatment showed that the rechallenge group had longer PFS than that of the non-rechallenge group (median 5.4 vs. 3.6 months, p = 0.0038), and the rechallenge group had a tendency to have longer OS than non-rechallenge group. These data suggest that rechallenge treatment with a platinum-based regimen could be second-line chemotherapy in patients with sensitive relapsed SCLC, especially those treated with chemotherapy alone as first-line therapy.

Role of Regulatory T cells in Airway Inflammation in Asthma.

Asthma is an allergic disease characterized by chronic airway inflammation, airway hyperresponsiveness (AHR), reversibility and remodeling. Inhaled corticosteroids (ICS) are effective in many patients with asthma. However, ICS are a controlling, but not but curative treatment, and there are still many patients with refractory and difficult-to-treat asthma. The evaluation of airway inflammation by induced sputum, non-specific AHR by methacholine, and asthmatic reactions by specific allergen challenge techniques are useful not only to investigate the pathogenesis of asthma but also to help develop new drugs for asthma management. Interactions between inflammation and regulation, such as between regulatory T cells (Tregs), and AHR were investigated using these techniques. The phenotypes are Tregs characterized by expression of the forkhead box P3 (Foxp3) and cytotoxic T-lymphocyte antigen 4 (CTLA4), which are potent mediators of dominant self-tolerance. Foxp3 and CTLA4 interact with each other. In patients with mild asthma, airway Tregs were decreased and airway eosinophilic inflammation was activated with accelerated AHR. Human asthmatic attack models by allergen challenge demonstrated that airway Tregs were decreased from the baseline with late asthmatic response (LAR) in patients with dual-responder asthma, and there was a significant correlation between change in airway Tregs and LAR. Airway Tregs were increased with escalation of interleukin-10 by ICS. The investigation of Tregs may lead to new strategies for management of asthma and other allergic diseases.

Successful treatment with an EGFR tyrosine kinase inhibitor Afatinib in a patient with combined small-cell lung Cancer with EGFR mutation.

Small-cell lung cancer (SCLC) combined with epidermal growth factor receptor (EGFR) mutations is extremely rare, and standard chemotherapeutic strategies have not yet been established. In the present study, we report a case of a 67-year-old man who presented with combined SCLC with EGFR mutation (exon 19 deletion). Systemic chemotherapy with cisplatin and irinotecan was initiated as first-line chemotherapy, and computed tomography findings revealed tumor shrinkage after two cycles of chemotherapy. However, after the third cycle of the treatment, disease progression was observed including the appearance of pleural and pericardial effusion. Cytologic examination of pleural and pericardial effusion revealed adenocarcinoma and no characteristics of SCLC, and an EGFR mutation was detected, in line with the initial diagnosis. Afatinib was then administered as second-line chemotherapy, which resulted in a partial response that lasted for 6 months. Re-biopsy after resistance to first-line chemotherapy suggested that the adenocarcinoma component harboring the EGFR mutation became dominant in association with disease progression, and afatinib provided clinical efficacy as second-line chemotherapy.

Characterization and validation of Entamoeba histolytica pantothenate kinase as a novel anti-amebic drug target.

The Coenzyme A (CoA), as a cofactor involved in >100 metabolic reactions, is essential to the basic biochemistry of life. Here, we investigated the CoA biosynthetic pathway of Entamoeba histolytica (E. histolytica), an enteric protozoan parasite responsible for human amebiasis. We identified four key enzymes involved in the CoA pathway: pantothenate kinase (PanK, EC 2.7.1.33), bifunctional phosphopantothenate-cysteine ligase/decarboxylase (PPCS-PPCDC), phosphopantetheine adenylyltransferase (PPAT) and dephospho-CoA kinase (DPCK). Cytosolic enzyme PanK, was selected for further biochemical, genetic, and phylogenetic characterization. Since E. histolytica PanK (EhPanK) is physiologically important and sufficiently divergent from its human orthologs, this enzyme represents an attractive target for the development of novel anti-amebic chemotherapies. Epigenetic gene silencing of PanK resulted in a significant reduction of PanK activity, intracellular CoA concentrations, and growth retardation in vitro, reinforcing the importance of this gene in E. histolytica. Furthermore, we screened the Kitasato Natural Products Library for inhibitors of recombinant EhPanK, and identified 14 such compounds. One compound demonstrated moderate inhibition of PanK activity and cell growth at a low concentration, as well as differential toxicity towards E. histolytica and human cells.

Glucose is preferentially utilized for biomass synthesis in pressure-overloaded hearts: evidence from fatty acid-binding protein-4 and -5 knockout mice.

Aims: The metabolism of the failing heart is characterized by an increase in glucose uptake with reduced fatty acid (FA) oxidation. We previously found that the genetic deletion of FA-binding protein-4 and -5 [double knockout (DKO)] induces an increased myocardial reliance on glucose with decreased FA uptake in mice. However, whether this fuel switch confers functional benefit during the hypertrophic response remains open to debate. To address this question, we investigated the contractile function and metabolic profile of DKO hearts subjected to pressure overload. Methods and results: Transverse aortic constriction (TAC) significantly reduced cardiac contraction in DKO mice (DKO-TAC), although an increase in cardiac mass and interstitial fibrosis was comparable with wild-type TAC (WT-TAC). DKO-TAC hearts exhibited enhanced glucose uptake by 8-fold compared with WT-TAC. Metabolic profiling and isotopomer analysis revealed that the pool size in the TCA cycle and the level of phosphocreatine were significantly reduced in DKO-TAC hearts, despite a marked increase in glycolytic flux. The ingestion of a diet enriched in medium-chain FAs restored cardiac contractile dysfunction in DKO-TAC hearts. The de novo synthesis of amino acids as well as FA from glycolytic flux was unlikely to be suppressed, despite a reduction in each precursor. The pentose phosphate pathway was also facilitated, which led to the increased production of a coenzyme for lipogenesis and a precursor for nucleotide synthesis. These findings suggest that reduced FA utilization is not sufficiently compensated by a robust increase in glucose uptake when the energy demand is elevated. Glucose utilization for sustained biomass synthesis further enhances diminishment of the pool size in the TCA cycle. Conclusions: Our data suggest that glucose is preferentially utilized for biomass synthesis rather than ATP production during pressure-overload-induced cardiac hypertrophy and that the efficient supplementation of energy substrates may restore cardiac dysfunction caused by energy insufficiency.

Retrospective Analysis of Treatment Outcomes and Geriatric Assessment in Elderly Malignant Lymphoma Patients.

In recent years, the Comprehensive Geriatric Assessment (CGA), which is used in gerontology to assess functioning in elderly individuals, has been said to be useful in geriatric oncology. Therefore, we examined whether items in the CGA were associated with survival time in elderly patients with non-Hodgkin lymphoma (NHL). We conducted the CGA for 93 patients aged ≥ 65 years who had undergone treatment for NHL retrospectively. The CGA includes activities of daily living, instrumental activities of daily living, mood, cognition, nutrition, and the Charlson comorbidity index. For each category, we divided subjects into a "good" group and a "poor" group. In regard to the Charlson comorbidity index, patients were divided into two groups using different cutoffs to divide the groups; the two groups were established according to the division with the largest significant difference in survival time. Multivariate analysis was then performed with the following prognostic factors affecting survival: all CGA items, NHL classification, stage, performance status, and doxorubicin use/non-use. We also performed similar analysis for 43 diffuse large B-cell lymphoma (DLBCL) patients who had undergone anthracycline treatment. Results are factors affecting survival in NHL cases included comorbidity score ≥ 6 (P < 0.0001), doxorubicin non-use (P = 0.005), and cognitive impairment (P = 0.0488). In cases of DLBCL, survival was affected by comorbidity score ≥ 5 (P = 0.0016). High comorbidity score was strongly associated with survival in both NHL and DLBCL.