Pharmacodynamic and Toxicity Studies of 6-Isopropyldithio-2'-guanosine Analogs in Acute T-Lymphoblastic Leukemia.

(1) Background: The research group has developed a new small molecule, 6-Isopropyldithio-2'-deoxyguanosine analogs-YLS004, which has been shown to be the most sensitive in acute T-lymphoblastic leukemia cells. Moreover, it was found that the structure of Nelarabine, a drug used to treat acute T-lymphoblastic leukemia, is highly similar to that of YLS004. Consequently, the structure of YLS004 was altered to produce a new small molecule inhibitor for this study, named YLS010. (2) Results: YLS010 has exhibited potent anti-tumor effects by inducing cell apoptosis and ferroptosis. A dose gradient was designed for in vivo experiments based on tentative estimates of the toxicity dose using acute toxicity in mice and long-term toxicity in rats. The study found that YLS010 at a dose of 8 mg/kg prolonged the survival of late-stage acute T-lymphoblastic leukemia mice in the mouse model study. (3) Conclusions: YLS010 has demonstrated specific killing effects against acute T-lymphoblastic leukemia both in vivo and in vitro. Preclinical studies of YLS010 offer a new opportunity for the treatment of patients with acute T-lymphoblastic leukemia in clinical settings.

Progress and trends on the analysis of nucleic acid and its modification.

Nucleic acid is a collective term of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), and it is an essential substance in all known life forms. As numerous of studies have shown that nucleic acids can be used as therapeutic agents and the abnormality of various nucleic acid and its modification level has been proven to be closely bound up with changes in diseases such as cancer, the development of analytical methods for the nucleic acid and its modification has become one of the research hotspots in the field of life sciences. Compared with classical nucleic acid detection methods such as Northern blotting, Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) and Polymerase Chain Reaction (PCR), novel analytical methods based on nanomaterials, nucleic acid amplification strategies and biosensors can better satisfy the needs for sensitivity and simplicity in current clinical diagnosis. Herein, the progress and trends of analysis of nucleic acid and its modification is discussed, aiming to provide guidance for the detection of nucleic acid and its modification in medical basic research and clinical diagnosis, treatment and prognosis.

Metabolic interactions between flumatinib and the CYP3A4 inhibitors erythromycin, cyclosporine, and voriconazole.

Flumatinib, indicated for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia, is a structural analog of imatinib and has shown higher potency than imatinib as a BCR-ABL inhibitor. In this paper, the metabolic profile of flumatinib was studied. It was found that CYP3A4 and CYP2C8 were the main cytochrome P450 enzyme substyles catalyzing the metabolism of flumatinib, and CYP3A4 has a stronger metabolic ability for flumatinib than CYP2C8. Erythromycin, cyclosporine, and voriconazole can inhibit the metabolism of flumatinib in vitro. Accordingly, co-administration of erythromycin and cyclosporine with flumatinib increased the plasma concentration and the systemic exposure of flumatinib in rats, which indicated that lower doses should be considered in clinical practice.

Epigenetic Mechanisms Underlying Organic Solute Transporter ß Repression in Colorectal Cancer.

Colorectal cancer (CRC) is known to be the third most common cancer disease and the fourth-leading cause of cancer-related deaths worldwide. Bile acid, especially deoxycholic acid and lithocholic acid, were revealed to play an important role during carcinogenesis of CRC. In this study, we found organic solute transporter ß (OSTß), an important subunit of a bile acid export transporter OSTα-OSTß, was noticeably downregulated in CRC. The decline of OSTß expression in CRC was determined by Western blot and real-time polymerase chain reaction (RT-PCR), whereas chromatin immunoprecipitation (ChIP) was used to evaluate the histone acetylation state at the OSTß promoter region in vivo and in vitro. CRC cell lines HT29 and HCT15 were treated with trichostation A (TSA) for the subsequent determination, including RT-PCR, small interfering RNA (siRNA) knockdown, ChIP, and dual-luciferase reporter gene assay, to find out which histone acetyltransferases and deacetylases exactly participated in regulation. We demonstrated that after TSA treatment, OSTß expression increased noticeably because of upregulated H3K27Ac state at OSTß promoter region. We found that stimulating the expression of p300 with CTB (Cholera Toxin B subunit, an activator of p300) and inhibiting p300 expression with C646 (an inhibitor of p300) or siRNA designed for p300 could control OSTß expression through modulating H3K27Ac state at OSTß promoter region. Therefore, downregulated expression of p300 in CRC may cause low expression of OSTß in CRC via epigenetic regulation. Generally, we revealed a novel epigenetic mechanism underlying OSTß repression in CRC, hoping this mechanism would help us to understand and inhibit carcinogenesis of CRC. SIGNIFICANCE STATEMENT: Organic solute transporter ß (OSTß) expression is lower in colon cancer tissues compared with adjacent normal tissues. We revealed the epigenetic mechanisms of it and proved that p300 controls OSTß expression through modulating H3K27Ac state at OSTß promoter region and hence causes low expression of OSTß in colorectal cancer.

Development of a UHPLC-MS/MS method for the quantification of ilaprazole enantiomers in rat plasma and its pharmacokinetic application.

In Korea and China, ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers. In this study, a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma, using R-lansoprazole as the internal standard. The enantioseparation was achieved on a CHIRALPAK AS-RH column (4.6 mm × 150 mm, i.d. 5 µm), with a mobile phase composed of 10 mM ammonium acetate aqueous solution and acetonitrile (60:40, V/V), at a flow-rate of 0.5 mL/min. The method was validated over the concentration range of 0.5-300 ng/mL for both, R- and S -ilaprazole. The lower limit of quantification was 0.5 ng/mL for both enantiomers. The relative standard deviation (RSD) of intra- and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9%, and the relative error accuracy (RE) ranged from -0.5%-2.0%. Finally, the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.

Upregulation of miR-489-3p and miR-630 inhibits oxaliplatin uptake in renal cell carcinoma by targeting OCT2.

Renal cell carcinoma (RCC) is one of the most common malignant tumors affecting the urogenital system, accounting for 90% of renal malignancies. Traditional chemotherapy options are often the front-line choice of regimen in the treatment of patients with RCC, but responses may be modest or limited due to resistance of the tumor to anticarcinogen. Downregulated expression of organic cation transporter OCT2 is a possible mechanism underlying oxaliplatin resistance in RCC treatment. In this study, we observed that miR-489-3p and miR-630 suppress OCT2 expression by directly binding to the OCT2 3'-UTR. Meanwhile, via 786-O-OCT2-miRNAs stable expression cell models, we found that miRNAs could repress the classic substrate 1-methyl-4-phenylpyridinium (MPP+), fluorogenic substrate N,N-dimethyl-4-(2-pyridin-4-ylethenyl) aniline (ASP+), and oxaliplatin uptake by OCT2 both in vitro and in xenografts. In 33 clinical samples, miR-489-3p and miR-630 were significantly upregulated in RCC, negatively correlating with the OCT2 expression level compared to that in adjacent normal tissues, using tissue microarray analysis and qPCR validation. The increased binding of c-Myc to the promoter of pri-miR-630, responsible for the upregulation of miR-630 in RCC, was further evidenced by chromatin immunoprecipitation and dual-luciferase reporter assay. Overall, this study indicated that miR-489-3p and miR-630 function as oncotherapy-obstructing microRNAs by directly targeting OCT2 in RCC.

Studies on the L-2-hydroxy-acid oxidase 2 catalyzed metabolism of S-mandelic acid and its analogues.

Mandelic acid (MA) is generally used as a biomarker of the exposure of styrene, which is classified as a class of hazardous environmental pollutants, and also used as an important chiral intermediate in pharmaceutical industry. The previous studies have found the excretion of phenylglyoxylic acid (PGA) in human and rat, a metabolite of MA, was mainly from S-MA rather than R-MA. The metabolic mechanism, however, is not clear. In order to explore the possible metabolic mechanism, the enzyme types involved in the stereoselectivity metabolism of MA were firstly studied, and then human and rat long-chain 2-hydroxy-acid oxidase 2 (HAO2) were recombinantly expressed to study the metabolic profiles of S-MA and its analogues. The results indicated that HAO2 might catalyze the stereoselectivity metabolism of S-MA in rats. Human HAO2 (hHAO2) and rat HAO2 (rHAO2) isozymes ß1 and ß2 were successfully cloned and expressed with high purity and good enzyme activities. The enzyme kinetic profiles of these enzymes were different for S-MA and analogues. The order of catalytic efficiency for hHAO2 and rHAO2, however, was reverse. It might be relevance to the difference in active amino acid residues and loop 4 in human and rat L-2-hydroxy acid oxidase isozyme B crystal structures.

Inhibition of histone deacetylase 7 reverses concentrative nucleoside transporter 2 repression in colorectal cancer by up-regulating histone acetylation state.

BACKGROUND AND PURPOSE: The concentrative nucleoside transporter 2 (CNT2) mediates the uptake of both natural nucleosides and nucleoside-derived drugs. Therefore, it is important both physiologically and pharmacologically. However, CNT2 expression is significantly repressed in colorectal cancer (CRC). Here, we have elucidated the mechanism(s) underlying CNT2 repression in CRC. EXPERIMENTAL APPROACH: Repression of CNT2 in tumour samples from patients with CRC was identified using Western blot and RT-qPCR. The histone acetylation state at the CNT2 promoter region was then evaluated with chromatin immunoprecipitation and trichostatin A (TSA) treatment. To find the key enzyme responsible for hypoacetylation at the CNT2 promoter region, siRNA knockdown and RT-qPCR were used. Effects of combining HDAC inhibitors and cladribine were studied in HCT15 and HT29 cells. KEY RESULTS: Histone deacetylase 7 was significantly up-regulated in CRC, leading to histone hypoacetylation at the CNT2 promoter region, especially at sites H3K9Ac, H3K18Ac and H4Ac. This hypoacetylation condensed the chromatin structure and reduced CNT2 expression. All these effects were reversed by treatment with TSA, a histone deacetylase inhibitor. In HCT15 and HT29 cells, inhibition of histone deacetylase increased cell uptake and decreased IC50 for cladribine. CONCLUSIONS AND IMPLICATIONS: Histone hypoacetylation due to increased levels of histone deacetylase 7 results in CNT2 repression in CRC tumour tissue and could lead to decreased uptake of and consequent resistance to nucleoside anti-cancer agents. Such resistance could be overcome by combining inhibitors of histone deacetylase with the nucleoside anti-cancer agent.

Evodia alkaloids suppress gluconeogenesis and lipogenesis by activating the constitutive androstane receptor.

The constitutive androstane receptor (CAR) is a key sensor in xenobiotic detoxification and endobiotic metabolism. Increasing evidence suggests that CAR also plays a role in energy metabolism by suppressing the hepatic gluconeogenesis and lipogenesis. In this study, we investigated the effects of two evodia alkaloids, rutaecarpine (Rut) and evodiamine (Evo), on gluconeogenesis and lipogenesis through their activation of the human CAR (hCAR). We found that both Rut and Evo exhibited anti-lipogenic and anti-gluconeogenic effects in the hyperlipidemic HepG2 cells. Both compounds can potently activate hCAR, and treatment of cells with hCAR antagonists reversed the anti-lipogenic and anti-gluconeogenic effects of Rut and Evo. The anti-gluconeogenic effect of Rut and Evo was due to the CAR-mediated inhibition of the recruitment of forkhead box O1 (FoxO1) and hepatocyte nuclear factor 4α (HNF4α) onto the phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) gene promoters. In vivo, we showed that treatment of mice with Rut improved glucose tolerance in a CAR-dependent manner. Our results suggest that the evodia alkaloids Rut and Evo may have a therapeutic potential for the treatment of hyperglycemia and type 2 diabetes. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

Expression of Bama Minipig and Human CYP3A Enzymes: Comparison of the Catalytic Characteristics with Each Other and Their Liver Microsomes.

Minipigs represent a good animal model because of the physiologic and anatomic similarities they share with humans. Three cytochrome P450 (CYP) 3A isozymes, CYP3A22, CYP3A29, and CYP3A46, have recently been reported to be expressed in Bama minipigs, which have limited data relating to their metabolic characteristics. In the present study, Bama minipig CYP3A22, CYP3A29, and CYP3A46 were recombinantly expressed and their metabolic manners were compared with those of human CYP3A4 and CYP3A5 and also human and Bama minipig liver microsomes. The results indicated Bama minipigs and human CYP3A enzymes showed similar metabolic kinetics and metabolite profiles using testosterone, midazolam, and nifedipine as substrates. However, the differences in amino acid sequences change the elimination velocity and metabolic preference of CYP3A enzymes to their substrates. It was demonstrated that CYP3A29, CYP3A4, and CYP3A5 were the most active enzymes for all reactions, whereas CYP3A46 was the least active enzyme. Substrate-dependent metabolism characteristics between human and Bama minipig CYP3A isoenzymes exist.

Bioactive natural compounds from the plant endophytic fungi Pestalotiopsis spp.

The plant-endophytic strains of the fungus Pestalotiopsis (Amphisphaeriaceae) are distributed throughout the world. Previous chemical investigation of members of the genus resulted in the discovery of various bioactive secondary metabolites including chromones, cytosporones, polyketides, terpenoids and coumarins with diverse structural features. The present report reviews the papers, which have appeared in the literature till now, concerning the isolation, structural elucidation, and biological activities of the secondary metabolites from Pestalotiopsis species.