Abemaciclib drives the therapeutic differentiation of acute myeloid leukaemia stem cells.

Self-renewal and differentiation arrest are two features of leukaemia stem cells (LSCs) responsible for the high relapse rate of acute myeloid leukaemia (AML). To screen drugs to overcome differentiation blockade for AML, we conducted screening of 2040 small molecules from a library of United States Food and Drug Administration-approved drugs and found that the cyclin-dependent kinase (CDK)4/6 inhibitor, abemaciclib, exerts high anti-leukaemic activity. Abemaciclib significantly suppressed proliferation and promoted the differentiation of LSCs in vitro. Abemaciclib also efficiently induced differentiation and impaired self-renewal of LSCs, thus reducing the leukaemic cell burden and improving survival in various preclinical animal models, including patient-derived xenografts. Importantly, abemaciclib strongly enhanced anti-tumour effects in combination with venetoclax, a B-cell lymphoma 2 (Bcl-2) inhibitor. This treatment combination led to a marked decrease in LSC-enriched populations and resulted in a synergistic anti-leukaemic effect. Target screening revealed that in addition to CDK4/6, abemaciclib bound to and inhibited CDK9, consequently attenuating the protein levels of global p-Ser2 RNA Polymerase II (Pol II) carboxy terminal domain (CTD), Myc, Bcl-2, and myeloid cell leukaemia-1 (Mcl-1), which was important for the anti-AML effect of abemaciclib. Collectively, these data provide a strong rationale for the clinical evaluation of abemaciclib to induce LSC differentiation and treat highly aggressive AML as well as other advanced haematological malignancies.

Tegaserod maleate exhibits antileukemic activity by targeting TRPM8.

To identify therapeutic targets in acute myeloid leukemia (AML), we conducted growth inhibition screens of 2040 small molecules from a library of FDA-approved drugs using a panel of 12 AML cell lines. Tegaserod maleate, a 5-hydroxytryptamine 4 receptor partial agonist, elicits strong anti-AML effects in vitro and in vivo by targeting transient receptor potential melastatin subtype 8 (TRPM8), which plays critical roles in several important processes. However, the role of TRPM8 remains incompletely described in AML, whose treatment is based mostly on antimitotic chemotherapy. Here, we report an unexpected role of TRPM8 in leukemogenesis. Strikingly, TRPM8 knockout inhibits AML cell survival/proliferation by promoting apoptosis. Mechanistically, TRPM8 exerts its oncogenic effect by regulating the ERK-CREB/c-Fos signaling axis. Hyperactivation of ERK signaling can be reversed by TRPM8 inhibition. Importantly, TRPM8 is overexpressed in AML patients, indicating that it is a new prognostic factor in AML. Collectively, our work demonstrates the anti-AML effects of tegaserod maleate via targeting TRPM8 and indicates that TRPM8 is a regulator of leukemogenesis with therapeutic potential in AML.

Immunogenicity and safety of 4 intramuscular standard-dose and high-dose hepatitis B vaccine in people living with HIV: a randomized, parallel-controlled trial.

OBJECTIVES: The immunogenicity of hepatitis B vaccine is unsatisfactory in the people living with HIV (PLHIV). Studies evaluating optimal regimens to enhance immunogenicity have heretofore been inconclusive. The study was to compare the immunogenicity and safety of the four standard-dose and high-dose regimens of hepatitis B vaccine among PLHIV. METHODS: A randomized, parallel-controlled trial was conducted between May, 2020, and January, 2021. Patients were randomly assigned to receive 3 or 4 doses of 20 or 60 µg of hepatitis B vaccine. Seroconversion rate, high-level response rate, and geometric mean concentration (GMC) of antibody to hepatitis B surface antigen (anti-HBs) at weeks 12 and 28 were the main outcome measures. RESULTS: At week 28, the seroconversion rate and GMC of anti-HBs in both IM20 × 4 and IM60 × 4 groups were significantly higher than those in the IM20 × 3 group (P < 0.05), and the GMC of anti-HBs was numerically higher in the IM60 × 4 group than that in the IM20 × 4 group. CONCLUSIONS: In PLHIV, both the four standard-dose and high-dose regimens significantly improved immunogenicity. The GMC of anti-HBs was numerically higher in the IM60 × 4 group than that in the IM20 × 4 group. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT03962803).

A comparative evaluation of the effect of SSI and Wx allelic variation on rice grain quality and starch physicochemical properties.

Near-isogenic lines Nip(Wxb/SSIj), Nip(Wxb/SSIi), Nip(wx/SSIj) and Nip(wx/SSIi) in the japonica rice Nipponbare (Nip) background containing allelic variation in the starch synthase gene SSI and Wx were investigated for cooked rice grain quality, starch morphology, pasting profiles, fine structure and crystallinity characteristics. Rice grains carrying the SSIi allele had poor cooked rice taste in the Wxb background. The introduction of SSIi caused reduced cooked rice grain elongation, especially in the wx background. Starch granule size was reduced in SSIi rice and the viscosity of flour and starch prepared from SSIi rice was markedly increased. Moreover, analysis of the starch molecular structure revealed a remarkable increase in the short amylopectin chains and reduced starch relative crystallinity compared with SSIj rice, which resulted in decreased gelatinization characteristics. These results suggest that SSI allelic variation has multiple effects on rice grain quality, as well as starch fine structure.

Improving rice eating and cooking quality by coordinated expression of the major starch synthesis-related genes, SSII and Wx, in endosperm.

KEY MESSAGE: Coordinated regulation of amylose and amylopectin synthesis via manipulation of SSII-2, SSII-3 and Wx expression in endosperm can improve rice eating and cooking quality. With increasing rice consumption worldwide, many researchers are working to increase the yield and improve grain quality, especially eating and cooking quality (ECQ). The rice ECQ is mainly controlled by the expression of starch synthesis-related genes (SSRGs) in endosperm. Although the Wx and SSII-3/SSIIa/ALK genes, two major SSRGs, have been manipulated to improve rice ECQ via various breeding approaches, new methods to further improve ECQ are desired. In our previous study, we enhanced rice ECQ by knocking down SSII-2 expression in the japonica Nipponbare cultivar (carrying the Wxb allele) via RNA interference. Herein, the SSII-2 RNAi was introduced into two Nipponbare-derived near-isogenic lines (NILs), Nip(Wxa) and Nip(wx), carrying Wxa and wx alleles respond for high and no amylose levels, respectively. Analysis of physicochemical properties revealed that the improved grain quality of SSII-2 RNAi transgenic lines was achieved by coordinated downregulating the expression of SSII-2, SSII-3 and Wx. To further confirm this conclusion, we generated ssii-2, ssii-3 and ssii-2ssii-3 mutants via CRISPR/Cas9 technique. The amylopectin structure of the resulting ssii-2sii-3 mutants was similar to that in SSII-2 RNAi transgenic lines, and the absence of SSII-2 decreased the amylose content, gelatinisation temperature and rapid visco-analyser profile, indicating essential roles for SSII-2 in the regulation of amylopectin biosynthesis and amylose content in rice endosperm. The effect of SSII-2 was seen only when the activity of SSII-3 was very low or lacking. Our study provides novel approaches and valuable germplasm resources for improving ECQ via plant breeding.

Predicting related factors of immunological response to hepatitis B vaccine in hemodialysis patients based on integration of decision tree classification and logistic regression.

The non/hypo-response rate of the hepatitis B vaccine among hemodialysis (HD) patients is still high, it is of great significance to explore the influencing factors and their relationships. To study the related factors and their relationships using logistic regression model and Chi-squared Automatic Interaction Detection (CHAID) decision tree model. A randomized controlled trial was conducted between February 2014 and May 2015 in China. HD patients being serologically negative for HBsAg and anti-HBs were randomly assigned to receive three intramuscular injections of the standard dose (20 µg) or high dose (60 µg) of recombinant hepatitis B vaccine at months 0, 1, and 6. Those with anti-HBs concentrations <100 mIU/mL, and ≥100 mIU/mL at month 7 were considered as non/hypo-response and high-level response, respectively. The non/hypo-response was 31.34% (89/284). After adjustment for confounders, logistic analysis showed that males (OR = 2.203, 95%CI: 1.109-4.367) and those with higher dialysis frequency (>4 times per 2 weeks) (OR = 1.918, 95%CI: 1.015-3.626) had a significant risk of non/hypo-response. While the CHAID analysis showed that gender, dose, and dialysis frequency were influencing factors of non/hypo-response, and gender is most important. The interaction between gender and dialysis frequency had the greatest effect on immunization, and followed by the interaction between dialysis frequency and vaccine dose. Taken together, gender, dose and dialysis frequency were influencing factors of hepatitis B vaccine in HD patients.

Characteristics of Grain Physicochemical Properties and the Starch Structure in Rice Carrying a Mutated ALK/SSIIa Gene.

The gelatinization temperature (GT) of endosperm starch influences rice eating and the cooking quality (ECQ). ALK encoding soluble starch synthase IIa (SSIIa) is the major gene determining grain GT in rice. Herein, we identified a spontaneous ALK mutant named ALKd, which resulted from a G/T single-nucleotide polymorphism (SNP) in exon 1 of the ALKc allele from the high-GT indica rice cultivar. Compared with grains from the ALKc near-isogenic line (NIL), NIL(ALKd) grains exhibited a high GT (2.3 °C) and improved retrogradation properties. The NIL(ALKd) grain starch contained an increased proportion of amylopectin intermediate chains (DP 13-24) at the expense of short chains (DP < 12), resulting in enhancements in both the crystallinity and the lamellar peak intensity compared with low-GT rice grains. Moreover, both NIL(ALKd) and NIL(ALKc) grains also featured a significantly lower apparent amylose content (AAC), harder gel consistency (GC), higher pasting curve, and poorer taste values in comparison to Nip(ALKa) grains. Taken together, this work provides novel insights underlying the allelic variation of the ALK gene in rice.

Genetic Dissection and Functional Differentiation of ALKa and ALKb, Two Natural Alleles of the ALK/SSIIa Gene, Responding to Low Gelatinization Temperature in Rice.

BACKGROUND: ALK is the key gene controlling rice gelatinization temperature (GT), which is closely associated with the eating and cooking quality (ECQ) in rice (Oryza sativa L.). To date, at least three ALK alleles are thought to be responsible for the diversity of GT among rice cultivars. The ALKc/SSIIai allele with high activity of the soluble starch synthase IIa (SSIIa) controls high GT, but the accurate functional difference between ALKa and ALKb alleles, both controlling low GT, is not clearly elucidated. Thus, we generated rice near-isogenic lines (NILs) by introducing different ALK alleles into the japonica cultivar Nipponbare (Nip) to clarify the discrepant effects of the two low-GT ALK alleles. RESULTS: The results showed that the function of two low-GT alleles (ALKa and ALKb) was different, and a much lower GT was observed in NIL(ALKb) rice grains compared with that of Nip(ALKa). Moreover, the starches of NIL(ALKb) grains had a higher degree of branching, higher setback, consistence and higher cool pasting viscosity than those of Nip(ALKa). The lower expression level of ALKb, compared with ALKa, resulted in depleted intermediate chains and increased short chains of amylopectin, thus affected the thermal and pasting properties of NILs' grains. Also, the data revealed both low-GT alleles were mainly found in temperate japonica, but more ALKb was found in other subpopulations such as indica as compared to ALKa. CONCLUSIONS: Overall, all the results suggested that the function between two low-GT alleles was different, and the distribution of ALKb was much wider than that of ALKa among the subpopulations of cultivated rice.

The interaction between amylose and amylopectin synthesis in rice endosperm grown at high temperature.

Starch is the abundant component in rice endosperm, and its microstructure determines the quality and functional properties of rice grain. It is well known that the starch fine structure is markedly influenced by high temperature during grain filling. However, it is poorly understood on the competition among starch synthesis related enzymes as well as the interaction between amylose and amylopectin biosynthesis under increased growing temperature. In this study, the non-waxy and waxy rice were planted under normal and high temperatures. Parameterizing analysis of the starch microstructure using mathematical models proved that amylose synthesis competed with the elongation of long amylopectin chains (DP＞60); Short chains of amylopectin can be used as the substrate for elongation of longer amylopectin chains; High temperature eliminated the consistency and regularity of the synthesis of amylose and amylopectin. In addition, enzyme assay proved the validity of fitting results from mathematical modeling analysis of starch.

Effects of high temperature on the fine structure of starch during the grain-filling stages in rice: mathematical modeling and integrated enzymatic analysis.

BACKGROUND: High temperature during the grain-filling stage is an important factor that can affect grain quality by altering the composition and structure of starch in rice. Therefore, it is important to study the regulatory mechanism of high temperature on rice starch biosynthesis. RESULTS: Two japonica cultivars, the waxy rice Taihunuo and non-waxy Nangeng 5055 were used to examine the effect of high temperature on the fine structure of starch during the grain-filling stage. Analysis of starch chain length distribution indicated that exposure to a high temperature increased the content of starch with medium-long chains and decreased the starch with short chains in both rice varieties. The differences of amylopectin synthesis responding to high temperature between waxy and non-waxy rice can shed light on the interactions of amylose and amylopectin synthesis under high temperature conditions. In the non-waxy variety, the amylose biosynthesis may affect the short and medium-long amylopectin biosynthesis under high temperature. A mathematical fitting model was used to interpret the fine structure of amylopectin and a series of parameters with enzymatical significance (ß and γ) were obtained. The fitting results showed that the waxy and non-waxy rice had similar responses to high temperature. The variations of the parameter response to high temperature was more remarkable in Taihunuo. Activity analysis of starch synthesis-related enzymes during the grain-filling stage demonstrated the reliability of model fitting results. CONCLUSION: The influences of high temperature on the fine structure of starch are similar between waxy and non-waxy rice. Amylose biosynthesis may affect amylopectin biosynthesis under high temperature. © 2018 Society of Chemical Industry.