Exogenous Feeding of Fructose and Phenylalanine Further Improves Betulin Production in Suspended Betula platyphylla Cells under Nitric Oxide Treatment

The aim of this study was to assay by NMR the metabolites which contribute to betulin production. 8-day-old suspended birch (Betula platyphylla) cells were treated by sodium nitroprusside (SNP) treatment, an NO donor, and 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), an NO-specific scavenger. The results showed that betulin production was increased by five times after SNP treatment, similar with that of the control under cPTIO treatment. Forty one metabolites were detected after SNP treatment or cPTIO treatment. Among them, 10 were found to significantly contribute to the differences observed between controls and treated cell culture samples. To validate the contribution of the above 10 metabolites to betulin production, myo-inositol, fructose and phenylalanine based on correlation analysis between the content of 12 metabolites and betulin were used to feed birch suspension cell cultures under SNP treatment. Exogenous feeding of fructose or phenylalanine further enhanced the betulin production under SNP treatment, but myo-inositol had the opposite result

Paeonol enhances TRAIL-induced apoptosis of human lung cancer cells by upregulating death receptors-4 and 5 via ROS-JNK/ERK-CHOP signaling

Purpose: To study the anti-proliferative potential of paeonol against lung cancer cells, and investigate its mechanism of action. Methods: Cell viability after paeonol treatment was determined with 3-(4,5-dimethylthiazol-2yl)2,5- diphenyltetrazolium bromide (MTT) assay, while paeonol- and TRAIL-mediated apoptosis was assayed using flow cytometry. Western blotting was used to assay the protein expression levels of phosphorylated JNK and ERK1/2, as well as protein expressions of pro-apoptotic factors/death receptors. 2′,7′-Dichlorodihydrofluorescein diacetate (H2DCFDA) staining and flow cytometry were used to monitor paeonol-induced reactive oxygen species (ROS) in the cells. Results: Paeonol treatment markedly reduced the proliferations of H1975 and BGC823 cells (p < 0.05). In H1975 and BGC823 cells, paeonol/TRAIL combination increased apoptosis to 88.43 and 87.21 %, respectively (p < 0.05). The levels of death receptor 4 (DR4) and death receptor 5 (DR5) were increased significantly by paeonol, relative to the control (p < 0.05). Paeonol also reduced the levels of decoy receptor-1 (DcR1) and decoy receptor-2 (DcR2), and increased the expression of CHOP (p < 0.05). The protein expression levels of survivin, Bcl-2, cFLIP and Bcl-xL were decreased, while protein levels of caspase3, caspase-8 and caspase-9 were upregulated by paeonol. Moreover, paeonol significantly upregulated p-ERK and p-JNK in H1975 and BGC823 cells, and also increased ROS levels, when compared to control (p < 0.05). Conclusion: Paeonol exerts anti-proliferative potential on lung cancer cells through upregulation of death receptors, activation of JNK/ERK-CHOP pathway and generation of ROS. Therefore, paeonol has a therapeutic potential for the management of lung cancer

Evaluation of Suitable Reference Genes for Quantitative Real-Time PCR in Various Tissues of <i>Apocynum venetum</i>

Apocynum venetum L. is an economically valuable plant with tolerance to drought and salinity. Its leaves are utilized in tea production and pharmaceuticals, while the stem bark serves as a high-quality fiber material. To gain insights into the gene expression patterns of A. venetum using quantitative real-time PCR (qRT-PCR), it is crucial to identify appropriate reference genes. This study selected nine candidate genes, including α-tubulin (TUA), β-tubulin (TUB), actin (ACT), cyclophilin (CYP), elongation factor-1α (EF-1α), the B family of regulatory subunits of protein phosphatase (PPP2R2, PPP2R3, and PPP2R5), and phosphoglycerate kinase (PGK), to determine the most appropriate reference genes in the leaf, stem, and root tissues of A. venetum. A comprehensive ranking by geNorm, NormFinder, BestKeeper, and RefFinder software and Venn diagrams was used to screen more stable reference genes in different tissues. The two most stable reference genes were CYP and TUA in leaves, PGK and PPP2R3 in stems, and TUA and EF-1α in roots, respectively. The relative expression values of the four genes involved in proline metabolism under polyethylene glycol treatment were used to validate the screened reference genes, and they exhibited highly stable expression levels. These findings represent the first set of stable reference genes for future gene expression studies in A. venetum. They significantly contribute to enhancing the accuracy and reliability of gene expression analyses in this economically important plant species

Putrescine Promotes Betulin Accumulation in Suspension Cell Cultures of Betula platyphylla by Regulating NO and NH4+ Production

Putrescine (Put) can enhance secondary metabolite production, but its intrinsic regulatory mechanism remains unclear. In this study, Put treatment promoted betulin production and gene expression of lupeol synthase (LUS), one of betulin synthetic enzymes. The maximum betulin content and gene expression level of LUS was 4.25 mg&middot;g&minus;1 DW and 8.25 at 12 h after 1 mmol&middot;L&minus;1 Put treatment, approximately two- and four-times that in the control, respectively. Put treatment increased the content of nitric oxide (NO) and its biosynthetic enzyme activity of nitrate reductase (NR) and NO synthase (NOS). Pretreatment of the birch suspension cells with NO-specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline- 1-oxyl-3-oxide (cPTIO), NR inhibitor sodium azide (NaN3), and NOS inhibitor NG-nitro-L-Arg methyl ester (L-NAME) decreased Put-triggered NO generation and blocked Put-induced betulin production. Put treatment improved the content of NH4+ and its assimilation enzyme activity of glutamate synthase and glutamate dehydrogenase. NH4+ supplementation also promoted NO and betulin production. Thus, the above data indicated that Put-induced NO was essential for betulin production. NO derived from NR, NOS, and NH4+ mediated betulin production in birch suspension cell cultures under Put treatment

The Study of External Dose Rate and Retained Body Activity of Patients Receiving 131I Therapy for Differentiated Thyroid Carcinoma

Radiation safety is an integral part of targeted radionuclide therapy. The aim of this work was to study the external dose rate and retained body activity as functions of time in differentiated thyroid carcinoma patients receiving 131I therapy. Seventy patients were stratified into two groups: the ablation group (A) and the follow-up group (FU). The patients’ external dose rate was measured, and simultaneously, their retained body radiation activity was monitored at various time points. The equations of the external dose rate and the retained body activity, described as a function of hours post administration, were fitted. Additionally, the release time for patients was calculated. The reduction in activity in the group receiving a second or subsequent treatment was more rapid than the group receiving only the initial treatment. Most important, an expeditious method was established to indirectly evaluate the retained body activity of patients by measuring the external dose rate with a portable radiation survey meter. By this method, the calculated external dose rate limits are 19.2, 8.85, 5.08 and 2.32 μSv·h−1 at 1, 1.5, 2 and 3 m, respectively, according to a patient’s released threshold level of retained body activity &lt;400 MBq. This study is beneficial for radiation safety decision-making

A paclitaxel prodrug with bifunctional folate and albumin binding moieties for both passive and active targeted cancer therapy

Folate receptor (FR) has proven to be a valuable target for chemotherapy using folic acid (FA) conjugates. However, FA-conjugated chemotherapeutics still have low therapeutic efficacy accompanied with side effects, resulting from complications such as short circulation half-life, limited tumor delivery, as well as high kidney accumulation. Herein, we present a novel FA-conjugated paclitaxel (PTX) prodrug which was additionally conjugated with an Evans blue (EB) derivative for albumin binding. The resulting bifunctional prodrug prolonged blood circulation, enhanced tumor accumulation, and consequently improved tumor therapeutic efficacy. Methods: Fmoc-Cys(Trt)-OH was coupled onto PTX at the 7'-OH position for further synthesis of ester prodrug FA-PTX-EB. The targeting ability was investigated using confocal microscopy and flow cytometry. The pharmacokinetics of this bifunctional compound was also studied. Meanwhile, cell viability was evaluated in normal cells and three cancer cell lines by MTT assay. In vivo therapeutic effect was tested on FR-α overexpressing MDA-MB-231 tumor model. Results: Compared with free PTX, the FA-PTX, PTX-EB and FA-PTX-EB prodrugs increased circulation half-life in mice from 2.19 to 3.82, 4.41, and 7.51 h, respectively. Pharmacokinetics studies showed that the FA-PTX-EB delivered more PTX to tumors than FA-PTX and free PTX. In vitro and in vivo studies demonstrated that FA-EB-conjugated PTX induced potent antitumor activity. Conclusion: FA-PTX-EB showed prolonged blood circulation, enhanced drug accumulation in tumors, higher therapeutic index, and lower side effects than either free PTX or monofunctional FA-PTX and EB-PTX. The results support the potential of using EB for the development of long-acting therapeutics