Advances of antitumor drug discovery in traditional Chinese medicine and natural active products by using multi-active components combination.

The antitumor efficacy of Chinese herbal medicines has been widely recognized. Leading compounds such as sterols, glycosides, flavonoids, alkaloids, terpenoids, phenylpropanoids, and polyketides constitute their complex active components. The antitumor monomers derived from Chinese medicine possess an attractive anticancer activity. However, their use was limited by low bioavailability, significant toxicity, and side effects, hindering their clinical applications. Recently, new chemical entities have been designed and synthesized by combining natural drugs with other small drug molecules or active moieties to improve the antitumor activity and selectivity, and reduce side effects. Such a novel conjugated drug that can interact with several vital biological targets in cells may have a more significant or synergistic anticancer activity than a single-molecule drug. In addition, antitumor conjugates could be obtained by combining pharmacophores containing two or more known drugs or leading compounds. Based on these studies, the new drug research and development could be greatly shortened. This study reviews the research progress of conjugates with antitumor activity based on Chinese herbal medicine. It is expected to serve as a valuable reference to antitumor drug research and clinical application of traditional Chinese medicine.

Steroid-resistant nephrotic syndrome caused by nuclear pore gene NUP133 variation.

Partially enlarged structure of NUP133: wild-type (upper) and mutant p.Lys966Asn (lower).

Efficacy evaluation of neoadjuvant immunotherapy plus chemotherapy for non-small-cell lung cancer: comparison of PET/CT with postoperative pathology.

OBJECTIVES: To assess the value of positron emission tomography/computed tomography (PET/CT) in the efficacy evaluation of patients undergoing neoadjuvant immunotherapy plus chemotherapy, and to analyze its correlation with postoperative pathology. METHODS: The PET/CT metabolic parameters and CT size were retrospectively analyzed before and after neoadjuvant immunotherapy plus chemotherapy in 67 patients with resectable stage II/IIIA non-small-cell lung cancer (NSCLC). CT assessment based on immune response evaluation criteria in solid tumor criteria ((i)RECIST) was compared with PET/CT assessment based on the response criteria in solid tumors (PERCIST). The correlations between PET/CT metabolic parameters and postoperative pathology were analyzed. The value of PET/CT in the efficacy evaluation was assessed. RESULTS: The PET/CT assessment showed high consistency with postoperative pathological evaluation, yet the CT assessment showed low consistency with postoperative pathological evaluation. The (i)RECIST and PERCIST criteria showed statistically significant differences (p < 0.001). The postoperative pathological response was negatively associated with ΔSUVmax (%) (r = - 0.812, p < 0.001), ΔSUVmean (%) (r = - 0.805, p < 0.001), and ΔSUVpeak (%) (r = - 0.800, p < 0.001). The cut-off values of 75.8 for ΔSUVmax (%), 67.8 for ΔSUVmean (%), and 74.6 for ΔSUVpeak (%) had the highest sensitivity and specificity. CONCLUSION: The PERCIST criteria are more sensitive and accurate than (i)RECIST criteria to identify more responders when evaluating the response of neoadjuvant immunotherapy plus chemotherapy for NSCLC. PET/CT shows high accuracy in predicting postoperative pathological response. Our study shows the important role PET/CT plays in the efficacy evaluation of NSCLC patients undergoing neoadjuvant immunotherapy plus chemotherapy, as well as in predicting the prognosis and guiding postoperative treatment. CLINICAL RELEVANCE STATEMENT: Neoadjuvant immunotherapy plus chemotherapy is highly effective in the treatment of non-small-cell lung cancer. And PET/CT played an important role in the efficacy evaluation following neoadjuvant immunotherapy plus chemotherapy for non-small-cell lung cancer. KEY POINTS: • Neoadjuvant immunotherapy plus chemotherapy is highly effective in the treatment of NSCLC. • The PERCIST criteria are more sensitive and accurate than (i)RECIST criteria to identify more responders when evaluating the response of neoadjuvant immunotherapy plus chemotherapy for NSCLC. • PET/CT played an important role in the efficacy evaluation; ΔSUVmax (%), ΔSUVmean (%), and ΔSUVpeak (%) following neoadjuvant immunotherapy plus chemotherapy for NSCLC had high consistency and strong correlations with postoperative pathology.

Sesquiterpenoids from the leaves of Chimonanthus nitens.

Two new sesquiterpenoids (1 and 3), one new natural product (2), and two known compounds (4 and 5) were isolated from the leaves of Chimonanthus nitens. Their structures were elucidated by spectroscopic analysis, and the absolute configuration of compound 3 was determined by the X-ray single-crystal diffraction analysis. The cytotoxicity of compounds 1-5 was evaluated at three concentrations on two human breast cancer cell lines (MDA-MB-468 and MDA-MB-231) by MTT assay. As a result, we found that the cytotoxicity was weak even with a concentration of these compounds up to 100 µM.

Rational Design of Daunorubicin C-14 Hydroxylase Based on the Understanding of Its Substrate-Binding Mechanism.

Doxorubicin is one of the most widely used antitumor drugs and is currently produced via the chemical conversion method, which suffers from high production costs, complex product separation processes, and serious environmental pollution. Biocatalysis is considered a more efficient and environment-friendly method for drug production. The cytochrome daunorubicin C-14 hydroxylase (DoxA) is the essential enzyme catalyzing the conversion of daunorubicin to doxorubicin. Herein, the DoxA from Streptomyces peucetius subsp. caesius ATCC 27952 was expressed in Escherichia coli, and the rational design strategy was further applied to improve the enzyme activity. Eight amino acid residues were identified as the key sites via molecular docking. Using a constructed screening library, we obtained the mutant DoxA(P88Y) with a more rational protein conformation, and a 56% increase in bioconversion efficiency was achieved by the mutant compared to the wild-type DoxA. Molecular dynamics simulation was applied to understand the relationship between the enzyme's structural property and its substrate-binding efficiency. It was demonstrated that the mutant DoxA(P88Y) formed a new hydrophobic interaction with the substrate daunorubicin, which might have enhanced the binding stability and thus improved the catalytic activity. Our work lays a foundation for further exploration of DoxA and facilitates the industrial process of bio-production of doxorubicin.

Biosynthesis of a novel ganoderic acid by expressing CYP genes from Ganoderma lucidum in Saccharomyces cerevisiae.

Ganoderic acids (GAs), a group of highly oxygenated lanostane-type triterpenoids from the traditional Chinese medicinal mushroom Ganoderma lucidum, possessed significant pharmacological activities. Due to the difficulty in its genetic manipulation, low yield, and slow growth of G. lucidum, biosynthesis of GAs in a heterologous host is a promising alternative for their efficient production. Heterologous production of a GA, 3-hydroxy-lanosta-8,24-dien-26-oic acid (HLDOA), was recently achieved by expressing CYP5150L8 from Ganoderma lucidum in Saccharomyces cerevisiae, but post-modification of HLDOA to biosynthesize other GAs remains unclear. In this study, another P450 from G. lucidum, CYP5139G1, was identified to be responsible for C-28 oxidation of HLDOA, resulting in the formation of a new GA 3,28-dihydroxy-lanosta-8,24-dien-26-oic acid (DHLDOA) by the engineered yeast, whose chemical structure was confirmed by UPLC-APCI-HRMS and NMR. In vitro enzymatic experiments confirmed the oxidation of HLDOA to DHLDOA by CYP5139G1. As the DHLDOA production was low (0.27 mg/L), to improve it, the strategy of adjusting the dosage of hygromycin and geneticin G418 to respectively manipulate the copy number of plasmids pRS425-Hyg-CYP5150L8-iGLCPR (harboring CYP5150L8, iGLCPR, and hygromycin-resistant gene hygR) and pRS426-KanMx-CYP5139G1 (harboring CYP5139G1 and G418-resistant gene KanMx) was adopted. Finally, 2.2 mg/L of DHLDOA was obtained, which was 8.2 fold of the control (without antibiotics addition). The work enriches the GA biosynthetic enzyme library, and is helpful to construct heterologous cell factories for other GA production as well as to elucidate the authentic GA biosynthetic pathway in G. lucidum. KEY POINTS: • Another P450 gene responsible for GA's post-modification was discovered and identified. • One new GA, DHLDOA, was identified and produced via engineered yeast. • With the balance of the two CYP genes expression, DHLDOA production was significantly improved.

FTO regulates ocular angiogenesis via m6A-YTHDF2-dependent mechanism.

Pathological ocular angiogenesis commonly results in visual impairment or even blindness. Unveiling the mechanisms of pathological angiogenesis is critical to identify the regulators and develop effective targeted therapies. Here, we used corneal neovascularization (CNV) model to investigate the mechanism of pathological ocular angiogenesis. We show that N6-methyladenosine (m6A) mRNA demethylation mediated by fat mass- and obesity-associated protein (FTO) could regulate endothelial cell (EC) function and pathological angiogenesis during CNV. FTO levels are increased in neovascularized corneas and ECs under pathological conditions. In vitro silencing of FTO in ECs results in reduced cellular proliferation, migration, and tube formation under both basal and pathological conditions. Furthermore, FTO silencing attenuates suture-induced CNV in vivo. Mechanically, FTO silencing in ECs could increase m6A methylation levels in critical pro-angiogenic genes, such as FAK, leading to decreased RNA stability and increased RNA decay through m6A reader YTHDF2. Our study demonstrates that FTO regulates pathological ocular angiogenesis by controlling EC function in an m6A-YTHDF2-dependent manner.

Effects of hyaluronic acid on differentiation of human amniotic epithelial cells and cell-replacement therapy in type 1 diabetic mice.

Our hypothesis is that hyaluronic acid may regulate the differentiation of human amniotic epithelial cells (hAECs) into insulin-producing cells and help the treatment of type 1 diabetes. Herein, a protocol for the stepwise in vitro differentiation of hAECs into functional insulin-producing cells was developed by mimicking the process of pancreas development. Treatment of hAECs with hyaluronic acid enhanced their differentiation of definitive endoderm and pancreatic progenitors. Endodermal markers Sox17 and Foxa2 and pancreatic progenitor markers Pax6, Nkx6.1, and Ngn3 were upregulated an enhanced gene expression in hAECs, but hAECs did not express the ß cell-specific transcription factor Pdx1. Interestingly, hyaluronic acid promoted the expression of major pancreatic development-related genes and proteins after combining with commonly used inducers of stem cells differentiation into insulin-producing cells. This indicated the potent synergistic effects of the combination on hAECs differentiation in vitro. By establishing a multiple injection transplantation strategy via tail vein injections, hAECs transplantation significantly reduced hyperglycemia symptoms, increased the plasma insulin content, and partially repaired the islet structure in type 1 diabetic mice. In particular, the combination of hAECs with hyaluronic acid exhibited a remarkable therapeutic effect compared to both the insulin group and the hAECs alone group. The hAECs' paracrine action and hyaluronic acid co-regulated the local immune response, improved the inflammatory microenvironment in the damaged pancreas of type 1 diabetic mice, and promoted the trans-differentiation of pancreatic α cells into ß cells. These findings suggest that hyaluronic acid is an efficient co-inducer of the differentiation of hAECs into functional insulin-producing cells, and hAECs treatment with hyaluronic acid may be a promising cell-replacement therapeutic approach for the treatment of type 1 diabetes.

CRISPR-Cas9 assisted functional gene editing in the mushroom Ganoderma lucidum.

The genetic manipulation of basidiomycete mushrooms is notoriously difficult and immature, and there is a lack of research reports on clustered regularly interspaced short palindromic repeat (CRISPR) based gene editing of functional genes in mushrooms. In this work, Ganoderma lucidum, a famous traditional medicinal basidiomycete mushroom, which produces a type of unique triterpenoid-anti-tumor ganoderic acids (GAs), was used, and a CRISPR/CRISPR-associated protein-9 nuclease (Cas9) editing system for functional genes of GA biosynthesis was constructed in the mushroom. As proof of concept, the effect of different gRNA constructs with endogenous u6 promoter and self-cleaving ribozyme HDV on ura3 disruption efficiency was investigated at first. The established system was applied to edit a cytochrome P450 monooxygenase (CYP450) gene cyp5150l8, which is responsible for a three-step biotransformation of lanosterol at C-26 to ganoderic acid 3-hydroxy-lanosta-8, 24-dien-26 oic acid. As a result, precisely edited cyp5150l8 disruptants were obtained after sequencing confirmation. The fermentation products of the wild type (WT) and cyp5150l8 disruptant were analyzed, and a significant decrease in the titer of four identified GAs was found in the mutant compared to WT. Another CYP gene involved in the biosynthesis of squalene-type triterpenoid 2, 3; 22, 23-squalene dioxide, cyp505d13, was also disrupted using the established CRISPR-Cas9 based gene editing platform of G. lucidum. The work will be helpful to strain molecular breeding and biotechnological applications of G. lucidum and other basidiomycete mushrooms.

Suppression of BMX-ARHGAP fusion gene inhibits epithelial-mesenchymal transition in gastric cancer cells via RhoA-mediated blockade of JAK/STAT axis.

Gastric cancer (GC) is one of the main causes of cancer-related mortality worldwide. Epithelial-mesenchymal transition (EMT) is an important biological process involving the process by which malignant tumor cells obtain the ability of migration, invasion, resistance of apoptosis, and degradation in the extracellular matrix. The current study aimed at investigating whether bone marrow X kinase Rho GTPase activating protein 12 (BMX-ARHGAP) fusion gene affects GC. First, short hairpin RNA (shRNA) against BMX-ARHGAP or BMX-ARHGAP were introduced to treat SGC-7901 cells with the highest BMX-ARHGAP among the five GC cell lines (SGC-7901, MKN-45, NCI-N87, SNU-5, and AGS). Next, cell vitality, drug resistance, migration, and invasion of SGC-7901 cells, activities of Rho and JAK/STAT axis, as well as EMT and lymph node metastasis (LNM) were evaluated. The survival rate of the mice was then determined through the transfection of the specific pathogen-free NOD-SCID mice with treated SGC-7901 cells. The results showed that BMX-ARHGAP expression was associated with the infiltration degree of GC tumor and poor prognosis for patients with GC. BMX-ARHGAP silencing was found to play an inhibitory role in the Rho and JAK/STAT axis to reduce cell vitality, drug resistance, migration and invasion, reverse EMT process, as well as inhibit LNM. BMX-ARHGAP overexpression was observed to have induced effects on GC cells as opposed to those inhibited by BMX-ARHGAP silencing. The survival rate of mice was increased after transfection with silenced BMX-ARHGAP. These findings provided evidence that the suppression of BMX-ARHGAP resulted in the inhibition of RhoA to restraint the development of GC cells by blocking the JAK/STAT axis.

BMX-ARHGAP fusion protein maintains the tumorigenicity of gastric cancer stem cells by activating the JAK/STAT3 signaling pathway.

BACKGROUND: Cancer stem cells (CSCs), drug-resistant cancer cell subsets, are known to be responsible for tumor metastasis and relapse. The JAK/STAT pathway, activated by SH2 domain, is known to regulate the tumor growth in gastric cancer (GC). Now, this study was designed to examine whether BMX-ARHGAP affects the GC stem cell properties and the underlying regulatory network via JAK/STAT axis. METHODS: BMX-ARHGAP expression was characterized in GC tissues and cells by RT-qPCR and western blot assay. When BMX-ARHGAP was overexpressed or silenced via plasmids or siRNA transfection, the stem cell properties were assessed by determining stem cell markers CD133, CD44, SOX2 and Nanog, followed by cell sphere and colony formation assays. Subsequently, cell proliferation and invasion were examined by conducting EdU and Transwell assays. The JAK/STAT3 signaling pathway activation was inhibited using AG490. ARHGAP12, BMX exon 10-11, BXM-SH2, JAK2 and STAT3 expression patterns were all determined to examine the regulatory network. The stem cell property in nude mice was also tested. RESULTS: BMX-ARHGAP was determined to be enriched in the GC. Overexpression of BMX-ARHGAP resulted in increased expression of CD133, CD44, SOX2 and Nanog protein, and accelerated proliferation and invasion of CD133+CD44+ cells as well as facilitated self-renewal potential of GC cells. However, the inhibition of the JAK/STAT3 signaling pathway reversed the stimulating effect of BMX-ARHGAP on proliferative and invasion abilities of CD133+CD44+ cells. The overexpression of BMX-ARHGAP was suggested to increase the BMX-SH2 protein expression via ARHGAP 5'UTR, and activate the JAK/STAT3 signaling pathway. Also, BMX-ARHGAP promoted tumor growth in nude mice. CONCLUSIONS: The aforementioned results demonstrated that the BMX-ARHGAP-dependent SH2 domain-JAK/STAT3 axis mediates the maintenance of GC stem cells, benefiting the development of new potential therapeutic targets for GC.

The influence of delay elimination communication on the prevalence of primary nocturnal enuresis-a survey from Mainland China.

AIMS: A pilot survey shows that primary nocturnal enuresis (PNE) prevalence has increased significantly during the past decade in Mainland China. Whether it is related to the delay of elimination communication (EC) is unclear. This study retrospectively investigated the influence of delayed EC on the PNE prevalence in children and adolescents in mainland China. METHODS: A cross-sectional study of PNE prevalence was performed by distributing 19 500 anonymous self-administered questionnaires to parents in five provinces of mainland China from July 2017 to October 2017. The questionnaires included sociodemographic data, family caregivers' information, and details about the disposable diapers (DD) usage, EC commencement date, psychological disorders, lower urinary tract symptoms, and family history of PNE in children and adolescents. The 2017 PNE prevalence was compared with that of 2006 in Mainland China. RESULTS: The total response rate was 97.04% (18 631 of 19 500) and 92.39% (18 016 of 19 500) qualified for statistical analysis. The PNE prevalence in 2017 has increased significantly compared to that of 2006 (7.30% vs 4.07%, P < 0.001). The PNE prevalence in children with EC starting before 6 months of age was significantly lower than those who start after 12 months of age. The longer DD were used and the later the beginning of EC, the higher the PNE prevalence was found. CONCLUSIONS: The PNE prevalence in Mainland China has increased significantly during the past 10 years. A longer use of DD and later onset of EC may be risk factors for PNE.

[Clinical effect of tacrolimus combined with glucocorticoid in the treatment of IgA nephropathy in children].

OBJECTIVE: To study the clinical effect and safety of tacrolimus (TAC) combined with glucocorticoid (GC) versus mycophenolate mofetil (MMF) combined with GC in the treatment of primary IgA nephropathy (IgAN) in children. METHODS: A retrospective analysis was performed for the clinical data of children with primary IgAN confirmed by renal pathology between January 2012 and December 2017. These children were divided into TAC group and MMF group according to the treatment regimen. Their clinical data before treatment and at 1, 3, and 6 months of treatment were collected, and the remission status of IgAN and adverse reactions were compared between the two groups. RESULTS: A total of 43 children who met the inclusion criteria were enrolled, with 15 children in the TAC group and 28 children in the MMF group. At 1 month of treatment, there was no significant difference in the remission status between the two groups (P>0.05). At 3 and 6 months of treatment, the TAC group had a significantly better remission status than the MMF group (P<0.05). At 1 month of treatment, the TAC group had higher serum albumin levels than the MMF group (P<0.05). Both groups had a significant increase in serum albumin levels at each time point after treatment (P<0.0083) and a significant increase in the glomerular filtration rate (GFR) at 3 and 6 months of treatment (P<0.0083). There was no significant difference in the overall incidence rate of adverse reactions between the two groups (P>0.05), but fungal infection was observed in one child from the TAC group. CONCLUSIONS: TAC combined with GC can effectively reduce urinary protein in children with primary IgAN, and it has a better short-term clinical effect than MMF combined with GC, with good safety.

Rational approach to improve ansamitocin P-3 production by integrating pathway engineering and substrate feeding in Actinosynnema pretiosum.

Ansamitocin P-3 (AP-3) produced by Actinosynnema pretiosum is an important antitumor agent for cancer treatment, but its market supply suffers from a low production titer. The role of AP-3 unusual glycolate unit supply on its biosynthesis was investigated in this work by overexpressing the responsible gene cluster asm13-17 in A. pretiosum (WT). As a result, the accumulation of AP-3 and its intermediate glyceryl-S-ACP in the asm13-17-overexpressed strain (Oasm13-17) versus WT was enhanced by 1.94 and 1.49-fold, respectively. To provide a higher supply of another precursor 3-amino-5-hydroxybenzoic acid, asmUdpg was also overexpressed in Oasm13-17 (Oasm13-17:asmUdpg), and an improved AP-3 titer of 680.5 mg/L was achieved in shake flasks. To further enhance the AP-3 titer, a rational fed-batch strategy was developed in bioreactor fermentation of Oasm13-17:asmUdpg; and by pulse feeding 15 g/L fructose and 1.64 g/L isobutanol at 60, 96, and 120 hr, the AP-3 production level reached 757.7 mg/L, which is much higher than ever reported in bioreactors. This work demonstrated that a rational approach combining precursor pathway engineering with substrate feeding was very effective in enhancing the AP-3 titer, and this enabling methodology would be helpful to industrial production of this eye-catching drug.

Biosynthesis of a ganoderic acid in Saccharomyces cerevisiae by expressing a cytochrome P450 gene from Ganoderma lucidum.

Ganoderic acid (GA), a triterpenoid from the traditional Chinese medicinal higher fungus Ganoderma lucidum, possesses antitumor and other significant pharmacological activities. Owing to the notorious difficulty and immaturity in genetic manipulation of higher fungi as well as their slow growth, biosynthesis of GAs in a heterologous host is an attractive alternative for their efficient bioproduction. In this study, using Saccharomyces cerevisiae as a host, we did a systematic screening of cytochrome P450 monooxygenase (CYP450) gene candidates from G. lucidum, which may be responsible for the GA biosynthesis from lanosterol but have not been functionally characterized. As a result, overexpression of a CYP450 gene cyp5150l8 was firstly found to produce an antitumor GA, 3-hydroxy-lanosta-8, 24-dien-26 oic acid (HLDOA) in S. cerevisiae, as confirmed by HPLC, LC-MS and NMR. A final titer of 14.5 mg/L of HLDOA was obtained at 120 hr of the yeast fermentation. Furthermore, our in vitro enzymatic experiments indicate that CYP5150L8 catalyzes a three-step biotransformation of lanosterol at C-26 to synthesize HLDOA. To our knowledge, this is the first report on the heterologous biosynthesis of GAs. The results will be helpful to the GA biosynthetic pathway elucidation and to future optimization of heterologous cell factories for GA production.

Efficient production and characterization of homopolymeric poly(3-hydroxyvalerate) produced by Bacillus strain PJC48.

Aliphatic polyester, poly(3-hydroxyvalerate) (PHV), is commonly produced as a granular component in bacterial cells of various species. Based on 16S rDNA gene sequence analysis, strain PJC48 was identified as a Bacillus species. The current study is aimed to screen for a high-yield strain that can produce PHV efficiently and to increase PHV product yield by optimizing the fermentative process. We identified a high-producer strain based on Nile red staining. Characterization of the PHV produced by PJC48 by nuclear magnetic resonance spectroscopy revealed that it consisted of (R)-3-hydroxyvalerate monomers. The suggested model was validated by response surface methodology. Optimization of the PHV yield resulted in an increase of 32.75% compared to control, with a maximum production of 1.64 g/L after 48 H.

H. pylori modifies methylation of global genomic DNA and the gastrin gene promoter in gastric mucosal cells and gastric cancer cells.

AIMS: The aim of this study was to evaluate the correlation between H. pylori infection and global DNA methylation, as well as the methylation levels of the gastrin promoters. MATERIALS AND METHODS: We constructed a eukaryotic expression vector, pcDNA3.1::cagA, and transfected it into GES-1 gastric mucosal cells and SGC-7901 gastric cancer cells. Both cell lines were infected with the H. pylori/CagA+ strain NCTC11637. Then, we detected global DNA methylation by capture and detection antibodies, followed by colorimetric quantification. The methylation levels of the gastrin promoter were evaluated by base-specific cleavage and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: In H. pylori/CagA+-infected GES-1 and SGC-7901 cells, the methylation levels of genomic DNA decreased by 49.4% and 18.8%, and in GES-1 and SGC-7901 cells transfected with pcDNA3.1::cagA, the methylation levels of genomic DNA decreased by 17.05% and 25.6%, respectively. Among 24 methylation sites detected in the gastrin promoter region, the methylation levels of 9 CpG sites were significantly decreased in H. pylori/CagA+-infected and pcDNA3.1:: cagA-transfected cells in comparison to corresponding control cells. CONCLUSION: These results indicate that H. pylori/CagA+ decreases the methylation of the genome and the gastrin promoter at some CpG sites in gastric mucosal and gastric cancer cells.

Combination of traditional mutation and metabolic engineering to enhance ansamitocin P-3 production in Actinosynnema pretiosum.

Ansamitocin P-3 (AP-3) is a maytansinoid with its most compelling antitumor activity, however, the low production titer of AP-3 greatly restricts its wide commercial application. In this work, a combinatorial approach including random mutation and metabolic engineering was conducted to enhance AP-3 biosynthesis in Actinosynnema pretiosum. First, a mutant strain M was isolated by N-methyl-N'-nitro-N-nitrosoguanidine mutation, which could produce AP-3 almost threefold that of wild type (WT) in 48 deep-well plates. Then, by overexpressing key biosynthetic genes asmUdpg and asm13-17 in the M strain, a further 60% increase of AP-3 production in 250-ml shake flasks was achieved in the engineered strain M-asmUdpg:asm13-17 compared to the M strain, and its maximum AP-3 production reached 582.7 mg/L, which is the highest as ever reported. Both the gene transcription levels and intracellular intermediate concentrations in AP-3 biosynthesis pathway were significantly increased in the M and M-asmUdpg:asm13-17 during fermentation compared to the WT. The good fermentation performance of the engineered strain was also confirmed in a lab-scale bioreactor. This work demonstrated that combination of random mutation and metabolic engineering could promote AP-3 biosynthesis and might be helpful for increasing the production of other industrially important secondary metabolites.

Hyaluronic acid enhances proliferation of human amniotic mesenchymal stem cells through activation of Wnt/ß-catenin signaling pathway.

This study investigated the pro-proliferative effect of hyaluronic acid (HA) on human amniotic mesenchymal stem cells (hAMSCs) and the underlying mechanisms. Treatment with HA increased cell population growth in a dose- and time-dependent manner. Analyses by flow cytometry and immunocytochemistry revealed that HA did not change the cytophenotypes of hAMSCs. Additionally, the osteogenic, chondrogenic, and adipogenic differentiation capabilities of these hAMSCs were retained after HA treatment. Moreover, HA increased the mRNA expressions of wnt1, wnt3a, wnt8a, cyclin D1, Ki-67, and ß-catenin as well as the protein level of ß-catenin and cyclin D1 in hAMSCs; and the nuclear localization of ß-catenin was also enhanced. Furthermore, the pro-proliferative effect of HA and up-regulated expression of Wnt/ß-catenin pathway-associated proteins - wnt3a, ß-catenin and cyclin D1 in hAMSCs were significantly inhibited upon pre-treatment with Wnt-C59, an inhibitor of the Wnt/ß-catenin pathway. These results suggest that HA may positively regulate hAMSCs proliferation through regulation of the Wnt/ß-catenin signaling pathway.

TUC338 Overexpression Leads to Enhanced Proliferation and Reduced Apoptosis in Tongue Squamous Cell Carcinoma Cells In Vitro.

PURPOSE: Long noncoding RNAs are closely related to the development of tumors. In this study, we explored the contribution of the long noncoding RNA TUC338 to cellular processes in tongue squamous cell carcinoma (TSCC). MATERIALS AND METHODS: First, we detected TUC338 expression using quantitative reverse transcription-polymerase chain reaction in 25 patients. Then, we transfected a short hairpin RNA to silence TUC338 expression in the CAL-27 and SCC-9 cell lines. Tumor cell growth was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, and apoptosis and cell-cycle analyses were performed via flow cytometry. RESULTS: The results indicated that TUC338 was overexpressed in TSCCs (P < .05). In addition, silencing TUC338 in CAL-27 and SCC-9 cells inhibited cell growth and increased apoptosis significantly in vivo (P < .05). CONCLUSIONS: Long noncoding RNA TUC338 overexpression leads to enhanced proliferation and reduced apoptosis in TSCC.