- A Novel Agent Enhances the Chemotherapeutic Efficacy of Doxorubicin in MCF-7 Breast Cancer Cells. [Journal Article]
- Front Pharmacol 2016.:249.
We have previously demonstrated that DT-010, a novel conjugate of danshensu (DSS) and tetramethylpyrazine (TMP), displays anti-tumor effects in breast cancer cells both in vitro and in vivo. In the present study, we investigated whether DT-010 enhances the chemotherapeutic effect of doxorubicin (Dox) in MCF-7 breast cancer cells and exerts concurrent cardioprotective benefit at the same time. Our findings showed that DT-010 was more potent than TMP, DSS, or their combination in potentiating Dox-induced toxicity in MCF-7 cells. Co-treatment with DT-010 and Dox increased apoptosis in MCF-7 cells relative to Dox alone. Further study indicated that glycolytic capacity, glycolytic reserve and lactate level of MCF-7 cells were significantly inhibited after DT-010 treatment. DT-010 also increased the expression of the pro-survival protein GRP78, which was inhibited by co-treatment with Dox. Both endoplasmic reticulum stress inhibitor 4-PBA and knockdown of the expression of GRP78 protein potentiated DT-010-mediated apoptosis in MCF-7 cells. Moreover, DT-010 inhibited Dox-induced cardiotoxicity in H9c2 myoblasts. In conclusion, DT-010 and Dox confer synergistic anti-tumor effect in MCF-7 breast cancer cells through downregulation of the glycolytic pathway and inhibition of the expression of GRP78. Meanwhile, DT-010 also protects against Dox-induced cardiotoxicity.
- A data science approach to candidate gene selection of pain regarded as a process of learning and neural plasticity. [JOURNAL ARTICLE]
- Pain 2016 Aug 19.
The increasing availability of "big data" enables novel research approaches to chronic pain while also requiring novel techniques for data mining and knowledge discovery. We used machine-learning to combine the knowledge about n = 535 genes identified empirically as relevant to pain with the knowledge about the functions of thousands of genes. Starting from an accepted description of chronic pain as displaying systemic features described by the terms "learning" and "neuronal plasticity", a functional-genomics analysis proposed that among the functions of the 535 "pain genes" the biological processes "learning or memory" (p = 8.6 · 10) and "nervous system development" (p = 2.4 · 10) are statistically significantly over-represented as compared to the annotations to these processes expected by chance. Following establishment that the hypothesized biological processes were among important functional-genomics features of pain, a subset of n = 34 pain genes was found to be annotated with both GO terms. Published empirical evidence supporting their involvement in chronic pain was identified for almost all of these genes, including one gene identified in March, 2016 as being involved in pain. By contrast, such evidence was virtually absent in a randomly selected set of 34 other human genes. Hence, the present computational functional-genomics based method can be used for candidate gene selection, providing an alternative to established methods.
- Roles of reactive chlorine species in trimethoprim degradation in the UV/chlorine process: Kinetics and transformation pathways. [JOURNAL ARTICLE]
- Water Res 2016 Aug 5.:272-282.
The UV/chlorine process, which forms several reactive species including hydroxyl radicals (HO) and reactive chlorine species (RCS) to degrade contaminants, is being considered to be an advanced oxidation process. This study investigated the kinetics and mechanism of the degradation of trimethoprim (TMP) by the UV/chlorine process. The degradation of TMP was much faster by UV/chlorine compared to UV/H2O2. The degradation followed pseudo first-order kinetics, and the rate constant (k') increased linearly as the chlorine dosage increased from 20 μM to 200 μM and decreased as pH rose from 6.1 to 8.8. k' was not affected by chloride and bicarbonate but decreased by 50% in the presence of 1-mg/L NOM. The contribution of RCS, including Cl, Cl2(-) and ClO, to the degradation removal rate was much higher than that of HO and increased from 67% to 87% with increasing pH from 6.1 to 8.8 under the experimental condition. The increasing contribution of RCS to the degradation with increasing pH was attributable to the increase in the ClO concentration. Kinetic modeling and radical scavenging tests verified that ClO mainly attacked the trimethoxybenzyl moiety of TMP. RCS reacted with TMP much faster than HOCl/OCl(-) to form chlorinated products (i.e., m/z 325) and chlorinated disinfection byproducts such as chloroform, chloral hydrate, dichloroacetonitrile and trichloronitromethane. The hydroxylation and demethylation of m/z 325 driven by HO generated m/z 327 and m/z 341. Meanwhile, reactions of m/z 325 with HO and RCS/HOCl/OCl(-) generated dichlorinated and hydroxylated products (i.e., m/z 377). All the chlorinated products could be further depleted to produce products with less degree of halogenation in the UV/chlorine process, compared to dark chlorination. The acute toxicity to Vibrio fischeri by UV/chlorine was lower than chlorination at the same removal rate of TMP. This study demonstrated the importance of RCS, in particular, ClO, in the degradation of micropollutants in the UV/chlorine process.
- Incidence of hyponatremia with high dose trimethoprim-sulfamethoxazole exposure. [JOURNAL ARTICLE]
- Am J Med 2016 Aug 16.
Trimethoprim-sulfamethoxazole (TMP-SMX) is a commonly prescribed antibiotic used at high doses for treatment of pneumocystis pneumonia and other infections. Trimethoprim is structurally related to the potassium-sparing diuretic amiloride and has been associated with hyperkalemia and hyponatremia through blocking of epithelial sodium channels in the distal nephron. The incidence of hyponatremia in hospitalized patients treated with high dose TMP-SMX is unknown.We performed a single center retrospective chart review of all hospitalized patients who received high dose TMP-SMX (n=235) from January 2012 to July 2014. Patients with congestive heart failure, cirrhosis, estimated glomerular filtrate rate less than 30ml/min/1.73m(2), baseline hyponatremia, and those on other medications associated with hyponatremia were excluded. Hyponatremia was defined as a serum sodium <136meq/L.Analysis was restricted to 76 unique patients who received more than 8mg/kg/day of TMP for ≥3 days. Mean starting serum sodium at time of TMP-SMX initiation was 138.4 ± 2.1meq/L. Fifty five patients (72.3%) developed hyponatremia while on therapy, of which 43.6% (n=24) were cases of serum sodium <130mEq/L. Mean sodium at the time of nadir was 131.6 ± 5.1mEq/L. Hyponatremia was noted on average 5.5 days after initiation of therapy, with more severe hyponatremia development among African American patients. Urine sodium concentrations were available for 40.0% (22/55) of incident hyponatremia cases with mean urinary sodium of 104.8 ± 55.9mEq/L. Hyponatremia often resolved within three weeks drug discontinuation.There is a high incidence (72.3%) of hyponatremia associated with the use of high dose TMP-SMX among hospitalized patients. This is an overlooked and potentially reversible cause of hyponatremia.
- [Antitumor and Radioprotective Action of a Low-frequency Turbulent Magnetic Field]. [English Abstract, Journal Article]
- Radiats Biol Radioecol 2016 Mar-Apr; 56(2):177-89.
The results of experimental studies on the biological effects and mechanisms of action of antitumor and radio modifying weak low-frequency turbulent magnetic field (TMF) on tumor objects of different levels of integration are presented. The studies have been conducted in the Russian Cancer Research Center named after Blokhin of the Russian Academy of Medical Sciences using the methods and criteria applied for the evaluation of antitumor efficacy of new drugs and impacts. Studies of the direct TMP action on tumor cells demonstrate the inhibitory effect on the DNA synthesis, also shown is the ability of TMP to induce apoptosis. It has been shown that exposure to TMF increases the functional activity of phagocytes, which manifests itself in increased level of non-specific resistance of the organism to the tumor process, and represents one of the possible mechanisms of the antitumor action. The discovered radio modifying effect of TMP opens the prospects for its use in combination with radiotherapy. Possible hypotheses about biophysical mechanisms of the established biological effects of TMP are presented. The presence in this physical factor of its own antitumor activity can be of interest for further research.
- Trimethoprim-Sulfamethoxazole versus Placebo in Reducing the Risk of Toxoplasmic Retinochoroiditis Recurrences: A three-year follow up. [JOURNAL ARTICLE]
- Am J Ophthalmol 2016 Aug 10.
The purpose of this trial was to compare the effects of 1 year of treatment with trimethoprim/sulfamethoxazole (TMP-SMZ) versus a placebo in reducing the risk of toxoplasmic retinochoroiditis recurrences during a 3-year follow-up period.Randomized, double-masked clinical trial.This cohort included 141 volunteers recruited in Campinas, Brazil. Inclusion criterion was unilateral active recurrent toxoplasmic retinochoroiditis. All volunteers were treated with 1 tablet of TMP-SMZ (800mg/160mg) twice daily for 45 days, and all lesions healed after this treatment. After this initial treatment, the volunteers were randomly assigned to Group 1 (one TMP-SMZ tablet every two days for 311 days) or Group 2 (one identical placebo tablet containing starch with no active ingredients every two days for 311 days). At the second and third-years follow-up appointments, none of the volunteers received treatment unless a new recurrence episode had occurred. The primary outcomes were recurrent toxoplasmic retinochoroiditis within the first year of follow up and recurrent toxoplasmic retinochoroiditis within the third year of follow up.The cumulative probability of recurrence at 1, 2, and 3 years of follow up were, respectively, 13.0% (9/69), 17.4% (12/69), and 20.3% (14/69) in the placebo group and 0% (0/72) in the TMP-SMZ group (P < .001, log-rank test). There was no case of multiple recurrences in the same individual. No treatment-limiting toxicity or side effects were observed in either group. New recurrences were more frequent among female volunteers.TMP-SMZ may be used safely for prophylaxis of recurrent toxoplasmic retinochoroiditis, with long-term benefits.
- Tetramethylpyrazine Ameliorates Rotenone-Induced Parkinson's Disease in Rats: Involvement of Its Anti-Inflammatory and Anti-Apoptotic Actions. [JOURNAL ARTICLE]
- Mol Neurobiol 2016 Aug 11.
Parkinson's disease (PD) is a slowly progressive neurodegenerative movement disorder. Apoptosis, neuroinflammation, and oxidative stress are the current hypothesized mechanisms for PD pathogenesis. Tetramethylpyrazine (TMP), the major bioactive component of Ligusticum wallichii Franchat (ChuanXiong), Family Apiaceae, reportedly has anti-apoptotic, anti-inflammatory and antioxidant effects. This study investigated the role of 'TMP' in preventing rotenone-induced neurobiological and behavioral sequelae. A preliminary dose-response study was conducted where rats received TMP (10, 20, and 40 mg/kg, i.p.) concomitantly with rotenone (2 mg/kg, s.c.) for 4 weeks. Catalepsy, locomotor activity, striatal dopamine content, and tyrosine hydroxylase "TH" and α-synuclein immunoreactivity were evaluated. The selected TMP dose (20 mg/kg) was used for western blot analysis of Bax, Bcl2, and DJ-1, immunohistochemical detection of nuclear factor kappa B (NF-кB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and glial fibrillary acidic protein (GFAP) expression, in addition to biochemical analysis of caspase-3 activity, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) levels. Results showed that TMP (20 mg/kg) significantly improved midbrain and striatal TH expression and striatal dopamine content as well as the motor deficits, compared to rotenone-treated group. These results were correlated with reduction in caspase-3 activity and α-synuclein expression, along with improvement of midbrain and striatal Bax/Bcl2 ratio compared to rotenone-treated group. TMP also attenuated rotenone-induced upregulation of Nrf2/HO-1 pathway. Furthermore, TMP downregulated rotenone-induced neuroinflammation markers: NF-кB, iNOS, COX2, and GFAP expression in both the midbrain and striatum. Taken together, the current study suggests that TMP is entitled to, at least partially, preventing PD neurobiological and behavioral deficits by virtue of its anti-apoptotic, anti-inflammatory, and antioxidant actions.
- Dataset for an analysis of tourism and economic growth: A study of Sri Lanka. [Journal Article]
- Data Brief 2016 Sep.:723-5.
We use the sample from 1978 to 2014 for the paper (doi:10.1016/j.tmp.2016.05.005). The data on GDP at constant 2005 USD (US dollar), and the gross fixed capital formation at constant 2005 USD are extracted from the World Bank (2015). The labour stock which includes direct and indirect employment and the tourism receipts (in USD) are sourced from the Sri Lanka Tourism Development Authority (http://www.sltda.lk/statistics). Tourism receipts as a per cent of GDP is used to measure tourism demand. The capital stock data is computed using perpetual inventory method, where a depreciation rate of 8 per cent is assumed with the initial capital stock as 1.05 times the GDP of 1969 at constant 2005 USD. The output per worker and capital per worker is computed by dividing the GDP and capital stock by the labour stock, respectively.
- CSTMP induces apoptosis and mitochondrial dysfunction in human myeloma RPMI8226 cells via CHOP-dependent endoplasmic reticulum stress. [JOURNAL ARTICLE]
- Biomed Pharmacother 2016 Aug 1.:776-784.
The natural product tetramethylpyrazine (TMP) and resveratrol have a variety of biologic activities, including anti-cancer effects. However the pharmacological function of CSTMP (a newly designed and synthesized TMP and resveratrol derivative) in cancer have not been elucidated.In RPMI8226 cells, the cytotoxic effects and apoptosis were detected by MTT and Double staining for Annexin V-FITC and propidium iodide (PI). The protein and mRNA expression levels were detected by Real Time PCR and Western blot, respectively. The localization of cleaved caspase-12 was evaluated by immunofluorescent staining. The activation of caspase were measured by colorimetric assays and Western blot.CSTMP showed significantly cytotoxic effects and induced apoptosis in RPMI8226 cells. Caspase activation, Cytochrome c release and Bax, Bcl-2 and Bcl-XL levels analyses demonstrated that the anti-cancer effect of CSTMP in RPMI8226 cells was mediated by promoting caspase- and mitochondria-dependent apoptosis. In addition, CSTMP induced the increased expression of endoplasmic reticulum (ER) stress related proteins (CHOP, GRP78, GRP94 and cleaved caspase-12) and the activation of multiple branches of ER stress transducers (PERK-eIF2α, IRE1α and ATF6). Moreover, knockdown of CHOP by siRNA markedly inhibited CSTMP-induced cytotoxic effects, caspases activity and mitochondrial dysfunction in RPMI8226 cells.Our results indicated that CSTMP could induce apoptosis and mitochondrial dysfunction in RPMI8226 cells via CHOP-dependent ER stress.
- Emergence of Plasmid-Borne dfrA14 Trimethoprim Resistance Gene in Shigella sonnei. [Journal Article]
- Front Cell Infect Microbiol 2016.:77.
The most common mechanism of trimethoprim (TMP)-resistance is the acquisition of dihydrofolate reductase enzyme resistant to this drug. Previous molecular characterization of TMP-genes resistance in Chilean isolates of Shigella sonnei searching for dfrA1 and dfrA8, showed solely the presence of dfrA8 (formerly dhfrIIIc). However, these genetic markers were absent in S. sonnei strains further isolated during an outbreak in 2009. To identify the TMP-resistance gene in these strains, a genomic DNA library from a TMP-resistant (TMP(R)) S. sonnei representative strain for the outbreak was used to clone, select and identify a TMP-resistance marker. The TMP(R) clone was sequenced by primer walking, identifying the presence of the dfrA14 gene in the sul2-strA'-dfrA14-'strA-strB gene arrangement, harbored in a native 6779-bp plasmid. The same plasmid was isolated by transforming with a ~4.2 MDa plasmid extracted from several TMP(R) S. sonnei strains into Escherichia coli. This plasmid, named pABC-3, was present only in dfrA14-positive strains and was homologous to a previously described pCERC-1, but different due to the absence of an 11-bp repetitive unit. The distribution of dfrA1, dfrA8, and dfrA14 TMP-resistance genes was determined in 126 TMP(R) S. sonnei isolates. Most of the strains (96%) carried only one of the three TMP-resistance genes assessed. Thus, all strains obtained during the 2009-outbreak harbored only dfrA14, whereas, dfrA8 was the most abundant gene marker before outbreak and, after the outbreak dfrA1 seems have appeared in circulating strains. According to PFGE, dfrA14-positive strains were clustered in a genetically related group including some dfrA1- and dfrA8-positive strains; meanwhile other genetic group included most of the dfrA8-positive strains. This distribution also correlated with the isolation period, showing a dynamics of trimethoprim genetic markers prevalent in Chilean S. sonnei strains. To our knowledge, dfrA14 gene associated to a small non-conjugative plasmid was detected for the first time in Shigella. Apparently, the strain causing the outbreak must have been introduced, changing drastically the genetic distribution of trimethoprim resistance in Chilean S. sonnei strains.