Improved trends in survival and engraftment after single cord blood transplantation for adult acute myeloid leukemia

Unrelated cord blood transplantation (CBT) is an alternative curative option for adult patients with acute myeloid leukemia (AML) who need allogeneic hematopoietic cell transplantation (HCT) but lack an HLA-matched related or unrelated donor. However, large-scale data are lacking on CBT outcomes for unselected adult AML. To investigate the trends of survival and engraftment after CBT over the past 22 years, we retrospectively evaluated the data of patients with AML in Japan according to the time period of CBT (1998–2007 vs 2008–2013 vs 2014–2019). A total of 5504 patients who received single-unit CBT as first allogeneic HCT for AML were included. Overall survival (OS) at 2 years significantly improved over time. The improved OS among patients in ≥ complete remission (CR)3 and active disease at CBT was mainly due to a reduction of relapse-related mortality, whereas among patients in first or second CR at CBT, this was due mainly to a reduction of non-relapse mortality. The trends of neutrophil engraftment also improved over time. This experience demonstrated that the survival and engraftment rate after CBT for this group has improved over the past 22 years.Subject terms: Acute myeloid leukaemia, Cancer immunotherapy     

Constipation Is a Frequent Problem Associated with Vascular Complications in Patients with Type 2 Diabetes: A Cross-sectional Study

Objective Diabetes is recognized as an underlying disease of constipation. However, the prevalence of constipation varies according to the diagnostic criteria applied. We investigated the prevalence of constipation based on the new guideline for constipation in Japanese patients with type 2 diabetes and examined the relationship with the clinical background, including diabetic vascular complications. Methods Questionnaire surveys including items concerning the diagnosis and treatment status of constipation were administered to 410 patients with type 2 diabetes. Results Although 29% of the patients considered that they had experienced constipation (self-judged), only 14% had consulted a physician about constipation. The prevalence of chronic constipation based on the guideline was 26%. After including laxative users, constipation was finally found in 36%. Despite the use of laxatives (n=81), 51% of the patients were still diagnosed with chronic constipation. Patients with constipation (chronic constipation or laxative use) were significantly older and had a longer duration of diabetes than those without constipation. The body mass index (BMI) of patients with constipation (24.9±3.8 kg/m²) was significantly lower than that of those without constipation (26.3±4.6 kg/m²). Diabetic neuropathy (49% vs. 32%) and coronary heart disease (CHD) (27% vs. 13%) were significantly more frequent in the patients with constipation than in those without constipation. A multivariate logistic regression analysis revealed that gender, BMI, diabetic neuropathy, insulin use, and CHD were significantly associated with constipation. Conclusion An accurate diagnosis of constipation is desirable in patients with type 2 diabetes because constipation is independently associated with CHD.     

Effect of vitamin E in gastric mucosal injury induced by ischaemia-reperfusion in nitric oxide-depleted rats

BACKGROUND: Neutrophil infiltration and lipid peroxide accumulation are involved in reperfusion-induced gastric mucosal injury in nitric oxide-depleted rats. AIM: To assess the effect of vitamin E on this injury. METHODS: After ischaemia-reperfusion, the total area of erosions, lipid peroxide contents in gastric mucosa, and gastric neutrophil accumulation were compared between nitric oxide-depleted rats with deficient, normal, and increased vitamin E intake over 8 weeks. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in gastric mucosa as indices of lipid peroxidation and neutrophil infiltration. RESULTS: The total area of erosions was significantly increased in the vitamin E-deficient group compared with the sufficient-intake and vitamin-supplemented groups. Both thiobarbituric acid-reactive substances and myeloperoxidase activity also were significantly increased in the vitamin E-deficient group compared with others. The total area of erosions closely paralleled the increases in both thiobarbituric acid-reactive substances and myeloperoxidase activity. CONCLUSION: These results indicate that the inhibition of lipid peroxidation and interference with neutrophil infiltration by vitamin E may be responsible for its cytoprotective effect in ischaemia-reperfusion.     

Inhibition of autophagy by chloroquine makes chemotherapy in nasopharyngeal carcinoma more efficient

Objectives

A combination of platinum-based chemotherapy and radiotherapy is the standard treatment for nasopharyngeal carcinoma (NPC). However, the efficacy of chemotherapy has reached a plateau. Many autophagy studies suggest that autophagy can either promote or suppress to cancer progression. Thus, a role of autophagy in the acquisition of chemoradioresistance has recently been a notable event. Therefore, we examined the relationship between autophagy and chemotherapy in NPC.

Effects of converting enzyme inhibitor (SQ 20881) on changes in blood pressure and plasma aldosterone induced by angiotensin I or acute hemorrhage in rabbits

The effects of angiotensin converting enzyme inhibitor (CEI) upon blood pressure and plasma aldosterone (PA) were studied in rabbits with a simultaneous infusion of angiotensin I (ANG I) or with hemorrhagic hypotension. Pretreatment with CEI (SQ 20881), 1.0 mg/Kg, inhibited the effects of infused ANG I, 30 ng/Kg/min, upon PA and blood pressure at 30 min of the infusion, but the inhibition on PA was not significant at 60 min of the infusion. The same dose of CEI was ineffective in blocking the effect of 100 ng/Kg/min of ANG I on PA and blood pressure even at 30 min of the infusion. In rabbits with hemorrhagic hypotension, injection of CEI resulted in the decrement in blood pressure, whereas no decrement in blood pressure was observed in normal control rabbits. This study suggests that CEI exerts it's effect in part by inhibiting conversion of ANG I to angiotensin II (ANG II), but this can't exclude other mechanisms.     

Gender and age differences in lifestyle factors related to hypertension in middle-aged civil service employees

The aim of this study is to identify lifestyle factors related to hypertension in man and woman workers, and to investigate age and gender differences in the relationships of the factors. From 6,000 civil service employees (4,937 men and 1,063 women) aged 40-69 years, information on lifestyle-related factors such as stress, exercise habits, preference for salty taste, alcohol drinking and smoking habits, and body mass index, as well as age and family history of hypertension was obtained through self-administered questionnaires in 1997. Hypertension was defined as either a systolic blood pressure > or = 140 mmHg, a diastolic blood pressure > or = 90 mmHg, or undergoing treatment for hypertension, and was present by 37.0% in men and 19.6% in women. Only body mass index was a significant lifestyle-related risk factor common to both genders with an odds ratio and its 95% confidence interval in parentheses of 2.2 (2.0-2.5) for men and 3.2 (2.3-4.6) for women. Men and women who preferred salty taste showed multivariate adjusted odds ratios of 0.9 (0.8-1.1) and 1.5 (1.1-2.2) for hypertension, respectively. In the stratified subanalysis, women aged 50 years and over had a significant odds ratio of 2.7 (1.5-4.9), whereas women aged 40-49 years and men of all age classes failed to show significant relationships. Salt intake was suggested to be a key factor for hypertension particularly for women after menopause.     

A two-component protein condensate of the EGFR cytoplasmic tail and Grb2 regulates Ras activation by SOS at the membrane

We reconstitute a phosphotyrosine-mediated protein condensation phase transition of the ∼200 residue cytoplasmic tail of the epidermal growth factor receptor (EGFR) and the adaptor protein, Grb2, on a membrane surface. The phase transition depends on phosphorylation of the EGFR tail, which recruits Grb2, and crosslinking through a Grb2-Grb2 binding interface. The Grb2 Y160 residue plays a structurally critical role in the Grb2-Grb2 interaction, and phosphorylation or mutation of Y160 prevents EGFR:Grb2 condensation. By extending the reconstitution experiment to include the guanine nucleotide exchange factor, SOS, and its substrate Ras, we further find that the condensation state of the EGFR tail controls the ability of SOS, recruited via Grb2, to activate Ras. These results identify an EGFR:Grb2 protein condensation phase transition as a regulator of signal propagation from EGFR to the MAPK pathway.

Recently, a class of phenomena known as protein condensation phase transitions has begun to emerge in biology. Originally identified in the context of nuclear organization (1) and gene expression (2), a distinct two-dimensional protein condensation on the cell membrane has now been discovered in the T cell receptor (TCR) signaling system involving the scaffold protein LAT (3–5). TCR activation results in phosphorylation of LAT on at least four distinct tyrosine sites, which subsequently recruit the adaptor protein Grb2 and the signaling molecule PLCγ via selective binding interactions with their SH2 domains. Additional scaffold and signaling molecules, including SOS, GADS, and SLP76, are recruited to Grb2 and PLCγ through further specific protein–protein interactions (6, 7). Multivalency among some of these binding interactions can crosslink LAT molecules in a two-dimensional bond percolation network on the membrane surface. The resulting LAT protein condensate resembles the nephrin:NCK:N-WASP condensate (8) in that both form on the membrane surface under control of tyrosine phosphorylation and exert at least one aspect of functional control over signaling output via a distinct type of kinetic regulatory mechanism (9–11). The basic molecular features controlling the LAT and nephrin protein condensates are common among biological signaling machinery, and other similar condensates continue to be discovered (12, 13). The LAT condensation shares downstream signaling molecules with the EGF-receptor (EGFR) signaling system, raising the question if EGFR may participate in a signaling-mediated protein condensation itself.EGFR signals to the mitogen-activated protein kinase (MAPK) pathway and controls key cellular functions, including growth and proliferation (14–16). EGFR is a paradigmatic model system in studies of signal transduction, and immense, collective scientific effort has revealed the inner workings of its signaling mechanism down to the atomic level (17). EGFR is autoinhibited in its monomeric form. Ligand-driven activation is achieved through formation of an asymmetric receptor dimer in which one kinase activates the other to phosphorylate the nine tyrosine sites in the C-terminal tails (17, 18). There is an obvious conceptual connection between EGFR and the LAT signaling system in T cells. The ∼200-residue–long cytoplasmic tail of EGFR resembles LAT in that both are intrinsically disordered and contain multiple sites of tyrosine phosphorylation that recruit adaptor proteins, including Grb2, upon receptor activation (19). Phosphorylation at tyrosine residues Y1068, Y1086, Y1148, and Y1173 in the EGFR tail creates sites to which Grb2 can bind via its SH2 domain. EGFR-associated Grb2 subsequently recruits SOS, through binding of its SH3 domains to the proline-rich domain of SOS. Once at the membrane, SOS undergoes a multistep autoinhibition-release process and begins to catalyze nucleotide exchange of RasGDP to RasGTP, activating Ras and the MAPK pathway (20).While these most basic elements of the EGFR activation mechanism are widely accepted, larger-scale features of the signaling complex remain enigmatic. A number of studies have reported higher-ordered multimers of EGFR during activation, including early observations by Förster Resonance Energy Transfer and fluorescence lifetime studies (21–23), as have more recent studies using single molecule (24, 25) and computational methods (26). Structural analyses and point mutation studies on EGFR have identified a binding interface enabling EGFR asymmetric dimers to associate (27), but the role of these higher-order assemblies remains unclear. At the same time, many functional properties of the signaling system remain unexplained as well. For example, EGFR is a frequently altered oncogene in human cancers, and drugs (including tyrosine kinase inhibitors) targeting EGFR signaling have produced impressive initial patient responses (28). All too often, however, these drugs fail to offer sustained patient benefits, in large part because of poorly understood resistance mechanisms (29). Physical aspects of the cellular microenvironment have been implicated as possible contributors to resistance development (30), and there is a growing realization that EGFR possesses kinase-independent (e.g., signaling independent) prosurvival functions in cancer cells (31). These points fuel speculation that additional layers of regulation over the EGFR signaling mechanism exist, including at the level of the receptor signaling complex itself.Here we report that EGFR undergoes a protein condensation-phase transition upon activation. We reconstituted the cytoplasmic tails of EGFR on supported bilayers and characterized the system behavior upon interaction with Grb2 and SOS, using total internal reflection fluorescence (TIRF) imaging. This experimental platform has been highly effective for revealing both phase-transition characteristics and functional signaling aspects of LAT protein condensates (4, 5, 10, 32–34). Published reports on the LAT system to date have emphasized SOS (or the SOS proline-rich [PR] domain) as a critical crosslinking element. Titrating the SOS PR domain into an initially homogeneous mixture of phosphorylated LAT and Grb2 revealed a sharp transition to the condensed phase, which we have also observed with the EGFR:Grb2:SOS system. Under slightly different conditions, however, we report observations of an EGFR:Grb2 condensation-phase transition without any SOS or other crosslinking molecule. We show that crosslinking is achieved through a Grb2–Grb2 binding interface. Phosphorylation on Grb2 at Y160 as well as a Y160E mutation [both reported to disrupt Grb2–Grb2 binding (35, 36)] were observed to prevent formation of EGFR condensates. We note that the evidence of Grb2–Grb2 binding we observed occurred in the context of EGFR-associated Grb2, which is localized to the membrane surface; free Grb2 dimers are not necessary.The consequence of EGFR condensation on downstream signaling is characterized by mapping the catalytic efficiency of SOS to activate Ras as a function of the EGFR condensation state. SOS is the primary Ras guanine nucleotide exchange factor (GEF) responsible for activating Ras in the EGFR-to-MAPK signaling pathway (37–40). At the membrane, SOS undergoes a multistep process of autoinhibition release before beginning to activate Ras. Once fully activated, SOS is highly processive, and a single SOS molecule can activate hundreds of Ras molecules before disengaging from the membrane (41–43). Autoinhibition release in SOS is a slow process, which necessitates that SOS be retained at the membrane for an extended time in order for Ras activation to begin (5, 10). This delay between initial recruitment of SOS and subsequent initiation of its Ras GEF activity provides a kinetic proofreading mechanism that essentially requires SOS to achieve multivalent engagement with the membrane (e.g., through multiple Grb2 or other interactions) in order for it to activate any Ras molecules.Experimental results described here reveal that Ras activation by SOS is strongly enhanced by EGFR condensation. Calibrated measurements of both SOS recruitment and Ras activation confirmed enhanced SOS catalytic activity on a per-molecule basis, in addition to enhanced recruitment to the condensates. These results suggest that a Grb2-mediated EGFR protein condensation-phase transition is a functional element controlling signal propagation from EGFR downstream to the MAPK signaling pathway.