Capillary electrophoresis-based assay of phosphofructokinase-1

Using CE to confirm the activity of fluorescent miRFP670-LIMK1 protein produced for MST assays directly in cell lysate

LIMK1 is a promising therapeutic target for multiple pathologies. Its holistic study seems crucial, as none of its inhibitors has passed clinical trials. The need for new fluorescent probes for the study of enzyme/ligand interactions is always increasing with the development of new analytical tools. A method for the assessment of LIMK activity directly in cell lysate is needed to ensure that interaction studies can be performed close to native conditions and by using active enzymes. Here, we introduce a study of LIM Kinase activity and inhibition monitored directly in cell lysate by capillary electrophoresis (CE). The miRFP670-LIMK1 was prepared because it is a fluorescent fusion protein emitting in the red spectrum and is thus suitable for microscale thermophoresis (MST) affinity assays. A PDADMAC-coated capillary was mandatory to avoid adsorption issues. The results directly confirm, for the first time, that miRFP670-LIMK1 is still active in the cell lysate even when the miRFP670 fluorescent tag is attached to its C-terminal. The inhibition of miRFP670-LIMK1 activity in the presence of TH-257 was also confirmed by CE. The dissociation constant, Kd, of the interaction miRFP670-LIMK1/TH-257 was then evaluated by MST, again directly in the cell lysate without any purification step. Submicromolar cellular on-target activity was revealed (Kd = 9 nM), confirming that TH-257 is suitable as a chemical probe for LIMK1. This study presents an innovative application of CE as a direct approach to verify, in a straightforward and simple manner, without purification or radioactivity, if an enzymatic target maintains its functionality after labeling. This work also highlights the complementarity of CE and MST in advancing pharmaceutical development under conditions that closely mimic those in vivo.

Exploring the Link Between Noncoding RNAs and Glycolysis in Colorectal Cancer

Glycolysis is implicated in the onset and progression of colorectal cancer (CRC) through its influence on the proliferation, invasiveness, chemoresistance and immune system evasion of neoplasm cells. Increasing evidence has shown that the abnormal expression of noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), in CRC is closely related to glycolysis. In this review, we present a synthesis of the latest research insights into the modulatory roles and distinct pathways of ncRNAs in the glycolytic process in CRC. This knowledge may pave the way for identifying novel therapeutic targets, as well as novel prognostic and diagnostic biomarkers for CRC.

Glycometabolic rearrangements--aerobic glycolysis in pancreatic cancer: causes, characteristics and clinical applications

Pancreatic cancer is one of the most malignant tumors worldwide, and pancreatic ductal adenocarcinoma is the most common type. In pancreatic cancer, glycolysis is the primary way energy is produced to maintain the proliferation, invasion, migration, and metastasis of cancer cells, even under normoxia. However, the potential molecular mechanism is still unknown. From this perspective, this review mainly aimed to summarize the current reasonable interpretation of aerobic glycolysis in pancreatic cancer and some of the newest methods for the detection and treatment of pancreatic cancer. More specifically, we reported some biochemical parameters, such as newly developed enzymes and transporters, and further explored their potential as diagnostic biomarkers and therapeutic targets.

The Impact of DJOS Surgery, a High Fat Diet and a Control Diet on the Enzymes of Glucose Metabolism in the Liver and Muscles of Sprague-Dawley Rats

The prevalence of diabetes type 2 (T2DM) and obesity is growing exponentially and becoming a global public health problem. The enzymes of glucose metabolism play a role in the pathogenesis of insulin resistance and T2DM. A pathophysiological link between different dietary patterns, HFD, obesity, T2DM and the enzymes of glucose metabolism can be used as a potential target in therapeutic strategies for the treatment of obesity, and T2DM. The aim of this study was to measure the impact of DJOS bariatric surgery and different types of dietary patterns on glycogen synthase kinase 3 α (GSK-3α), glycogen phosphorylase (PYGM, PYGL), and phosphofructokinase (PFK-1) concentrations in liver and soleus muscle tissues of rats. After 8 weeks on a high-fat diet (HF) or control diet (CD), rats underwent duodenal-jejunal omega switch (DJOS) or SHAM (control) surgery. After surgery, for the next 8 weeks, half of DJOS/SHAM animals were kept on the same diet as before, and half had a changed diet. The concentrations of GSK-3α, PYGM, PYGL and PFK-1 were measured in the soleus muscles and livers of the Sprague-Dawley rats. The type of diet applied before/after surgery had stronger impact on levels of selected metabolic enzymes than DJOS or SHAM surgery. The impact of DJOS surgery was visible for GSK-3α and PYGL concentration in the liver but not in the soleus muscle tissue. The type of bariatric surgery had an impact on liver GSK-3α concentration in all studied groups except the CD/CD group, where the impact of diet was stronger. DJOS bariatric surgery influenced the level of PYGL in the livers of rats maintained on the CD/CD diet but not from other groups. The dietary patterns applied before and after bariatric surgery, had a stronger impact on enzymes’ concentrations than DJOS surgery, and the strong, deleterious effect of an HF was observed. A change of the diet per se showed a negative impact on the enzymes’ tissue concentration.

Capillary electrophoretic assay of human acetyl-coenzyme A carboxylase 2

Human acetyl-coenzyme A carboxylase 2 catalyzes the carboxylation of acetyl coenzyme A to form malonyl coenzyme A, along with the conversion of magnesium-adenosine triphosphate complex to magnesium-adenosine diphosphate complex. A simple off-column capillary electrophoresis assay for human acetyl-coenzyme A carboxylase 2 was developed based on the separation of magnesium-adenosine triphosphate complex, magnesium-adenosine diphosphate complex, acetyl coenzyme A and malonyl coenzyme A with detection by ultraviolet absorption at 256 nm. When Mg²⁺ was absent from the separation buffer, the zones due to magnesium-adenosine triphosphate complex and magnesium-adenosine diphosphate complex both split and migrated as two separate peaks. With Mg²⁺ added to the separation buffer, magnesium-adenosine triphosphate complex and magnesium-adenosine diphosphate complex produced single peaks, and the reproducibility of peak shape and area improved for human acetyl-coenzyme A carboxylase 2 assay components. The final separation buffer used was 30.0 mM HEPES, 3.0 mM MgCl₂ , 2.5 mM KHCO₃ , and 2.5 mM potassium citrate at pH 7.50. The same buffer was used for the enzyme-catalyzed reaction (off-column). Inhibition of human acetyl-coenzyme A carboxylase 2 by CP-640186, a known inhibitor, was detected using the capillary electrophoresis assay.

Recent advances in screening of enzymes inhibitors based on capillary electrophoresis

Capillary electrophoresis with many advantages plays an important role in pharmaceutical analysis and drug screening. This review gives an overview on the recent advances in the developments and applications of capillary electrophoresis in the field of enzyme inhibitor screening. The period covers 2013 to 2017. Both the pre-capillary enzyme assays and in-capillary enzyme assays which include electrophoretically mediated microanalysis (EMMA) and immobilized enzyme microreactor (IMER) are summarized in this article.

Nanochannel-based electrochemical assay for transglutaminase activity

A novel nanochannel-based electrochemical approach to determine transglutaminase activity by using mesoporous silica thin film-coated electrodes.