Oral Chinese Herbal Medicine plus usual care for diabetic kidney disease: study protocol for a randomized, double-blind, placebo-controlled pilot trial

Background

Diabetic kidney disease (DKD) has become the leading cause of kidney failure, causing a significant socioeconomic burden worldwide. The usual care for DKD fails to achieve satisfactory effects in delaying the persistent loss of renal function. A Chinese herbal medicine, Tangshen Qushi Formula (TQF), showed preliminary clinical benefits with a sound safety profile for people with stage 2-4 DKD. We present the protocol of an ongoing clinical trial investigating the feasibility, efficacy, and safety of TQF compared to placebo in delaying the progressive decline of renal function for people with stage 2-4 DKD.

Methods

A mixed methods research design will be used in this study. A randomized, double-blind, placebo-controlled pilot trial will evaluate the feasibility, efficacy, and safety of TQF compared to placebo on kidney function for people with stage 2-4 DKD. An embedded semi-structured interview will explore the acceptability of TQF granules and trial procedures from the participant's perspective. Sixty eligible participants with stage 2-4 DKD will be randomly allocated to the treatment group (TQF plus usual care) or the control group (TQF placebo plus usual care) at a 1:1 ratio for 48-week treatment and 12-week follow-up. Participants will be assessed every 12 weeks. The feasibility will be assessed as the primary outcome. The changes in the estimated glomerular filtration rate, urinary protein/albumin, renal function, glycemic and lipid markers, renal composite endpoint events, and dampness syndrome of Chinese medicine will be assessed as the efficacy outcomes. Safety outcomes such as liver function, serum potassium, and adverse events will also be evaluated. The data and safety monitoring board will be responsible for the participants' benefits, the data's credibility, and the results' validity. The intent-to-treat and per-protocol analysis will be performed as the primary statistical strategy.

Discussion

Conducting a rigorously designed pilot trial will be a significant step toward establishing the feasibility and acceptability of TQF and trial design. The study will also provide critical information for future full-scale trial design to further generate new evidence supporting clinical practice for people with stage 2-4 DKD.

Trial registration number

https://www.chictr.org.cn/, identifier ChiCTR2200062786.

Renal-protective effects of Chinese medicinal herbs and compounds for diabetic kidney disease in animal models: protocol for systematic review and meta-analysis

BACKGROUND

Diabetic kidney disease (DKD) is a common and severe complication of diabetes that can lead to end-stage renal disease with no cure. The first-line drugs recommended by clinical guidelines fail to achieve satisfactory effects for people with DKD. A Chinese herbal medicine Tangshen Qushi Formula (TQF) shows preliminary efficacy and safety in preserving renal function for people with DKD, but the effects on comprehensive renal outcomes remain unclear. We will conduct a systematic review and meta-analysis to evaluate the effects of TQF herbs and their compounds identified from ultra-high performance liquid chromatography-MS/MS in diabetic animal models with renal outcomes.

METHODS

This protocol complies with the guideline Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. We will include studies investigating the effects of TQF herbs and compounds on diabetic rats or mice with renal outcomes. Six electronic databases will be searched from their inception to February 2023. Quality assessment will be conducted using SYRCLE's risk of bias tool. Standardized or weighted mean differences will be estimated for renal outcomes (creatinine, urea, proteinuria, histological changes, oxidative stress, inflammation, and kidney fibrosis). Data will be pooled using random-effects models. Heterogeneity across studies will be expressed as I2. Sensitivity analyses will explore treatment effects in adjusted models and within subgroups. Funnel plots and Egger's test will be used to explore publication bias.

DISCUSSION

The results of this review will provide valuable insights into the potential effects of TQF in managing DKD. The limitation is that the included studies will be animal studies from specific databases, and the interpretation of the findings must be cautious.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023432895. Registered on 19 July 2023 ( https://www.crd.york.ac.uk/PROSPERO/#recordDetails ).

Does Chinese herbal medicine (CHM) reduce colorectal adenoma (CRA) recurrence: protocol of a registry-based, cohort study and a qualitative interview

INTRODUCTION

Colorectal adenoma (CRA) is a precancerous lesion for colorectal cancer. Endoscopic resection is the first-line treatment for CRA. However, CRA recurrence rate is high. This proposed study aims to determine if Chinese herbal medicine (CHM) reduces CRA recurrence.

METHODS AND ANALYSIS

This project encompasses an observational, registry-based, cohort study and a nested qualitative study. The cohort study aims to include 364 postpolypectomy CRA participants at Guangdong Provincial Hospital of Chinese Medicine (GPHCM), China, with a follow-up phase of up to 1 year. In addition to routine care, these participants will receive a CHM treatment prescribed by experienced Chinese medicine (CM) clinicians. The CHM treatment encompasses CHM products and CHM formulae according to CM syndromes. The primary outcome is CRA recurrence rate at 1 year after enrolment. Secondary outcomes include characteristics of recurrent CRA, incidence of colorectal polyp (except for CRA), incidence of advanced CRA, incidence of colorectal cancer, improvement of gastrointestinal symptoms commonly seen in CRA patients, faecal occult blood test result, lipid level, fasting plasma glucose level, uric acid level, carcinoembryonic antigen, carbohydrate antigen 19-9, quality of life and safety evaluations. Logistic regression analysis will be used to explore the correlation between exposure and outcome. Qualitative interviews will be conducted among approximate 30 CRA patients from the cohort study and 10 CM practitioners in Department of Gastroenterology at GPHCM. Thematic analysis will be used to analyse qualitative data.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Human Research Ethics Committee (HREC) of GPHCM (YF2022-320-02) and registered at Royal Melbourne Institute of Technology (RMIT) HREC. The results will be disseminated in peer-reviewed journals and international academic conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200065713.

Oral Chinese herbal medicine in reducing the recurrence of colorectal adenoma after polypectomy: A protocol for the systematic review and meta-analysis

BACKGROUND

Colorectal adenoma (CRA) is a significant precancerous lesion of sporadic colorectal cancer (CRC). CRA is likely to recur after polypectomy, increasing the risk of CRC. Chinese herbal medicine (CHM) has been used to reduce CRA recurrence. This review aims to evaluate the effectiveness and safety of oral CHM in reducing CRA recurrence compared to other treatments (placebo, routine care, no treatment, and conventional medicine).

METHODS

We will search for randomised controlled trials (RCTs) from nine major biomedical databases in English and Chinese from their inception to July 2023. The RCTs that investigate the effects of oral CHM in reducing CRA recurrence compared to other treatments will be involved. We will exclude trials using CHM extract or external application of CHM, cohort study and cross-section study. The Cochrane Risk of Bias Tool version 2 will be used to assess the quality of included studies. Data will be analysed using Review Manager software 5.4 and STATA. The random effect model will be used. The heterogeneity of intervention effects will be tested by Chi2 (Cochrane Q) and I2 statistics. Funnel plots will assess publication bias if more than ten studies are included. Subgroup and sensitivity analysis will be conducted when possible.

DISCUSSION

This review will discuss the effectiveness and safety of oral CHM in reducing CRA recurrence. It will show the critical information for clinicians in the decision-making process and countries to develop clinical guidelines on CRA management. Systematic review registration PROSPERO CRD42023324197.

Benefits of herbal formulae containing Poria cocos (Fuling) for type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Poria cocos (Schw.) Wolf or Fuling is one of the top 10 most frequently prescribed herbs in China for the treatment of type 2 diabetes mellitus (T2DM).

OBJECTIVE

The purpose of this systematic review is to determine the additional benefit of Fuling formulae use in addition to hypoglycaemic agents for T2DM in randomised clinical trials.

METHODS

English (5) and Chinese (4) medical databases were searched from their inception to August 2021. RCTs that included Fuling in herbal formulae for T2DM were included. Risk of bias were assessed using the Cochrane Collaboration's procedures. Stata software (13.0) was used for data analysis.

RESULTS

Seventy-three RCTs (6,489 participants) with herbal formulae containing Fuling were included. Most studies were at risk of bias and strength of the evidence were low to moderate. Meta-analysis findings showed that the addition of formulae containing Fuling to hypoglycaemic agent-treatments could benefit people with T2DM by reducing fasting blood glucose (MD -0.82 [-0.93, -0.71]; I2 = 79.6%, P = 0.00), 2-hour postprandial blood glucose (MD-1.15 [-1.31, -0.98], I2 = 80%, P = 0.00) and haemoglobin A1c (MD-0.64 [-0.75, -0.53], I2 = 84.7%, P = 0.00). Adverse events were also significantly lower in the integrative group than in the hypoglycaemic alone group (RR 0.99 [0.93, 1.06], P = 0.87).

CONCLUSION

Evidence from this study supports the use of Fuling formulae combined with hypoglycaemic agents for T2DM. The combined therapies appear to be well tolerated.

TRAIL REGISTRATION

This review is registered with the PROSPERO international prospective register of systematic reviews (CRD42020214635).

Additional Benefit of Chinese Medicine Formulae Including Dioscoreae rhizome (Shanyao) for Diabetes Mellitus: Current State of Evidence

BACKGROUND

Chinese medicine has been used to treat diabetes symptoms for thousands of years. Dioscoreae rhizome or Shanyao is a Chinese medicinal herb that is routinely used in the treatment of diabetes mellitus (DM).

OBJECTIVE

The purpose of this study is to evaluate the evidence of the added benefits and safety of herbal formulae containing Shanyao in clinical studies and the possible mechanisms of Shanyao in the prevention and treatment of DM in experimental studies.

METHODS

We searched nine databases for randomized controlled trials (RCTs) that included Shanyao in the formulae in the treatment of type 2 DM. Furthermore, experimental studies on the prevention and treatment of DM by Shanyao in English- and Chinese-language databases were identified.

RESULTS

Fifty-three moderate quality RCTs with herbal formulae containing Shanyao were identified. Results from meta-analysis indicated that Shanyao alone or formulae containing Shanyao in addition to conventional treatments could benefit people with type 2 DM in lowering blood glucose, blood lipids and reducing insulin resistance. Moreover, adverse events were significantly lower in the CHM plus conventional group than those in the conventional group. Shanyao may exert the benefit through various mechanisms including inhibition of α-glucosidase and DPP-IV activity, increase of endogenous GLP-1 and immune regulating activities.

CONCLUSION

Evidence from this review suggested that there appeared to be added clinical benefits associated with the use of Shanyao for DM, whether as a food supplement or as a CHM combined with hypoglycemic agents with a good safety profile.

Acupuncture therapies for chronic obstructive pulmonary disease: a systematic review of randomized, controlled trials

CONTEXT

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality and is projected to be the third leading cause of death by 2030. Acupuncture, a traditional Chinese therapy, has been used for more than 2000 years to treat respiratory conditions and may treat COPD effectively. In previous literature reviews, researchers have noted significant heterogeneity among the included studies, and none of the reviewers found convincing evidence to recommend routine use of acupuncture therapies for COPD.

OBJECTIVE

This literature review examined the efficacy and safety of acupuncture therapies for patients with COPD in improving lung function, increasing exercise capacity, creating positive subjective changes in symptoms, and enhancing health-related quality of life (QoL).

DESIGN

The research team searched the following electronic databases from inception to April 2013: PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED), Embase (Elsevier), the China National Knowledge Infrastructure (CNKI), Chongqing VIP Information Company (CQVIP), the Chinese Biomedical Literature Database (CBM), and Wanfang Data. The review included randomized, controlled trials (RCTs) that examined the benefits of acupuncture or other related therapies for treatment of COPD. Data were extracted into a predefined form; risk of bias was assessed according to the Cochrane Risk of Bias tool; and statistical analyses were made.

RESULTS

In total, 16 studies were included in the review. The research team found that the acupuncture therapies used in these studies improved health-related QoL. The team's conclusions, comparing results from the interventions with placebo, were based on data from 3 questionnaires that the studies used: (1) the St George's Respiratory Questionnaire (SGRQ), with a mean difference (MD) of -8.33 units (95% CI, -13.13 to -3.53); (2) dyspnea on the Medical Research Council's (MRC's) dyspnea scale, with an MD of -0.34 units (95% CI, -0.38 to -0.30); and (3) the Dyspnea Visual Analogue Scale (DVAS), with an MD of -8.85 mm (95% CI, -11.81 to -5.89). Compared with placebo, acupuncture therapies also increased the distance walked in 6 min (6MWT), with an MD of -28.14 (95% CI, 23.92 to 32.36) compared with placebo. No benefit was seen on measures of lung function when acupuncture therapies were compared with either placebo or drug therapy.

CONCLUSION

Acupuncture therapies may result in clinically important improvements in QoL and dyspnea. Future high-quality RCTs should be undertaken to provide conclusive evidence concerning the benefits of acupuncture therapies in the treatment of COPD.

Therapeutic potential of Panax ginseng and ginsenosides in the treatment of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major global health burden and will become the third largest cause of death in the world by 2030. It is currently believed that an exaggerated inflammatory response to inhaled irritants, in particular cigarette smoke, cause progressive airflow limitation. This inflammation, where macrophages, neutrophils and lymphocytes are prominent, leads to oxidative stress, emphysema, airways fibrosis and mucus hypersecretion. COPD responds poorly to current anti-inflammatory treatments including corticosteroids, which produce little or no benefit. Panax ginseng has a long history of use in Chinese medicine for respiratory conditions, including asthma and COPD.

OBJECTIVES

In this perspective we consider the therapeutic potential of Panax ginseng for the treatment of COPD.

RESULTS

Panax ginseng and its compounds, ginsenosides, have reported effects through multiple mechanisms but primarily have anti-inflammatory and anti-oxidative effects. Ginsenosides are functional ligands of glucocorticoid receptors and appear to inhibit kinase phosphorylation including MAPK and ERK1/2, NF-κB transcription factor induction/translocation, and DNA binding. They also inhibit pro-inflammatory mediators, TNF-α, IL-6, IL-8, ROS, and proteases such as MMP-9. Panax ginseng protects against oxidative stress by increasing anti-oxidative enzymes and reducing the production of oxidants.

CONCLUSION

Given that Panax ginseng and ginsenosides appear to inhibit processes related to COPD pathogenesis, they represent an attractive therapeutic target for the treatment of COPD.

Panax ginseng therapy for chronic obstructive pulmonary disease: a clinical trial protocol and pilot study

Background

Panax ginseng (Ren shen) has been used to treat chronic obstructive pulmonary disease (COPD). This article aims to present a study protocol and pilot trial comparing P. ginseng with placebo for treating moderate to very severe COPD.

Methods

COPD was diagnosed spirometrically, with participants having a forced expiratory volume in one second (FEV1) of between 20% and 79% and FEV1 to forced vital capacity (FVC) ratio of less than 70%. Outcome measures included exacerbation rate, St. Georges Respiratory Questionnaire, COPD Assessment Test and Short-form Health Survey (SF-36). Other outcome measures included the six-minute walk test, FEV1, FVC, relief medication use, use of COPD-specific medical resources, and adverse events. The study is a randomized, double-blind, placebo controlled clinical trial. The method of this pilot trial was based on a planned full-scale trial except that participants were enrolled for ten weeks compared to 52 weeks. In the pilot trial, 14 participants (57–73 years old) with moderate to very severe COPD were recruited from a community health program at a public Chinese medicine hospital in Guangdong Province, China. After a 2-week run-in period, 10 participants were eligible for the study and were randomly assigned to either P. ginseng group (n = 5) (200 mg twice daily for four weeks) or placebo group (n = 5), and then followed-up for an additional 4 weeks for a total of 10 weeks.

Results

Nine participants completed the trial and one dropped out. The exacerbation rate could not be evaluated because there were no exacerbations. One participant in P. ginseng group reported events of sore throat, cough and fever. Trial investigators did not consider these events as COPD exacerbations or adverse events.

Conclusions

Participant recruitment, study design, data collection and outcome measurement have been tested in a pilot trial. A full-scale trial is warranted.

Oral Chinese herbal medicine combined with pharmacotherapy for stable COPD: a systematic review of effect on BODE index and six minute walk test

This systematic review evaluated the effects of Chinese herbal medicine (CHM) plus routine pharmacotherapy (RP) on the objective outcome measures BODE index, 6-minute walk test (6MWT), and 6-minute walk distance (6MWD) in individuals with stable chronic obstructive pulmonary disease (COPD). Searches were conducted of six English and Chinese databases (PubMed, EMBASE, CENTRAL, CINAHL, CNKI and CQVIP) from their inceptions until 18th November 2013 for randomized controlled trials involving oral administration of CHM plus RP compared to the same RP, with BODE Index and/or 6MWT/D as outcomes. Twenty-five studies were identified. BODE Index was used in nine studies and 6MWT/D was used in 22 studies. Methodological quality was assessed using the Cochrane Risk of Bias tool. Weaknesses were identified in most studies. Six studies were judged as 'low' risk of bias for randomisation sequence generation. Twenty-two studies involving 1,834 participants were included in the meta-analyses. The main meta-analysis results showed relative benefits for BODE Index in nine studies (mean difference [MD] -0.71, 95% confidence interval [CI] -0.94, -0.47) and 6MWT/D in 17 studies (MD 54.61 meters, 95%CI 33.30, 75.92) in favour of the CHM plus RP groups. The principal plants used were Astragalus membranaceus, Panax ginseng and Cordyceps sinensis. A. membranaceus was used in combination with other herbs in 18 formulae in 16 studies. Detailed sub-group and sensitivity analyses were conducted. Clinically meaningful benefits for BODE Index and 6MWT were found in multiple studies. These therapeutic effects were promising but need to be interpreted with caution due to variations in the CHMs and RPs used and methodological weakness in the studies. These issues should be addressed in future trials.

Ear acupressure for smoking cessation: study protocol for a randomised controlled trial

BACKGROUND

Smoking is the largest preventable cause of death and disease worldwide but smokers often fail to quit due to nicotine withdrawal symptoms. Current available pharmaceutical therapies may assist with smoking cessation but may have side effects. Ear acupressure (EAP) and ear acupuncture have been used for smoking cessation, and some positive results have been reported. The aim of the study is to assess the efficacy and safety of EAP in assisting individuals to quit smoking and/or support them in the management of nicotine withdrawal symptoms.

METHODS

This study will be a randomised, single-blind, sham-controlled study conducted at RMIT University in Melbourne, Australia. Adult smokers will be randomly assigned to receive EAP specifically for smoking cessation or nonspecific EAP treatments. After a 2-week run-in, participants will be treated once a week for 8 weeks and followed up for 12 weeks. The primary outcome measures will be 7 day point-prevalence cessation rate by self-report validated by expired carbon monoxide and nicotine withdrawal symptoms measured by the Mood and Physical Symptoms Score questionnaire. Secondary outcomes will be self-reported usage of nicotine replacement therapies, cigarette consumption, body weight change and quality of life. The safety end point will be self-reported adverse events associated with EAP. Intention-to-treat analysis will be applied.

DISCUSSION

Findings from this study will determine if this EAP intervention alone can be an effective and safe therapy to assist with smoking cessation and the management of nicotine withdrawal symptoms.

Interaction of herbal compounds with biological targets: a case study with berberine

Berberine is one of the main alkaloids found in the Chinese herb Huang lian (Rhizoma Coptidis), which has been reported to have multiple pharmacological activities. This study aimed to analyze the molecular targets of berberine based on literature data followed by a pathway analysis using the PANTHER program. PANTHER analysis of berberine targets showed that the most classes of molecular functions include receptor binding, kinase activity, protein binding, transcription activity, DNA binding, and kinase regulator activity. Based on the biological process classification of in vitro berberine targets, those targets related to signal transduction, intracellular signalling cascade, cell surface receptor-linked signal transduction, cell motion, cell cycle control, immunity system process, and protein metabolic process are most frequently involved. In addition, berberine was found to interact with a mixture of biological pathways, such as Alzheimer's disease-presenilin and -secretase pathways, angiogenesis, apoptosis signalling pathway, FAS signalling pathway, Hungtington disease, inflammation mediated by chemokine and cytokine signalling pathways, interleukin signalling pathway, and p53 pathways. We also explored the possible mechanism of action for the anti-diabetic effect of berberine. Further studies are warranted to elucidate the mechanisms of action of berberine using systems biology approach.

Current and future therapeutic targets of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systematic autoimmune disease which affects about 1% of the population world wide. This article aimed to identify current therapeutic targets for RA based on data from the literature and drug target related databases. Identified targets were further analysed using a powerful bioinformatics tool, PANTHER (Protein ANalysis THrough Evolutionary Relationships). Additionally, we explored future possible therapeutic targets for RA and discussed the possibility of discovering novel drugs with improved efficacy and reduced toxicity for RA treatment. Data on current clinical drugs for RA treatment were extracted from the US Food and Drugs Administration (FDA) website. Candidate targets of RA were extracted from three online databases: Drugbank, Therapeutic Target Database (TTD) and Potential Drug Target Database (PDTD). A total of 95 clinical protein targets for RA have been identified and were analysed using the PANTHER Classification System. According to the PANTHER analysis, most commonly involved pathways in current RA targeting includes inflammation mediated by chemokine and cytokine signalling pathways, angiogenesis, p53 pathway, de novo purine biosynthesis, T-cell activation, apoptosis signalling pathway and vascular endothelial growth factor (VEGF) receptor signalling pathway. Accordingly, current clinical agents for the treatment of RA mainly include corticosteroids, non-steriodal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs (DMARDs). In addition, a number of investigational targets for RA have been identified and many novel drugs for RA therapy are under investigation. Current approaches to handle RA aim to ameliorate inflammation, to relieve pain, and most importantly to protect the cartilage, joints and bones from further damage by blocking proinflammatory molecules and inhibit the production of matrix-degrading factors. New drugs for RA with improved efficacy and safety should be developed.

Structure, function, regulation and polymorphism of human cytochrome P450 2A6

The CYP2A6 gene spans a region of approximately 6 kb pairs consisting of 9 exons and has been mapped to the long arm of chromosome 19 (between 19q12 and 19q13.2). The CYP2A6 protein has 494 amino acids and is an important hepatic Phase I enzyme that metabolizes approximately 3% of therapeutic drugs (n > 30; e.g. valproic acid, pilocarpine, tegafur, fadrozole, ifosfamide, cyclophosphamide, nicotine, tamoxifen, promazine, propofol, and cisapride), environmental toxicants (e.g. gasoline additives), and many procarcinogens such as nitrosamines and aflatoxin B(1). This enzyme also participates in the biotransformation of several endogenous compounds such as retinoid acids and steroids. Because CYP2A6 is responsible for 70-80% of the initial metabolism of nicotine, CYP2A6 has been proposed to be a novel target for smoking cessation. Site-directed mutagenesis and homology modeling studies have identified a number of amino acids (e.g. F300, A301, S208, S369, and L370) that play a role in substrate recognition and binding. CYP2A6 shows a crystal structure with a compact, hydrophobic active site with Asn297 serving as one hydrogen bond donor and orienting substrates for regio-selective oxidation. CYP2A6 contains the second smallest active site cavity among the human CYPs with known structures. The regulation mechanism of CYP2A6 expression is not fully understood, but available data suggest that several nuclear receptors including constitutive androstane receptor, pregnane X receptor and glucocorticoid receptor are involved in its regulation. Pilocarpine and tranylcypromine are commonly used as selective competitive inhibitors of CYP2A6. Selegiline, methoxsalen, (R)-(+) menthofuran and decursinol angelate are mechanism-based inhibitors of CYP2A6. Both in vitro and in vivo studies have demonstrated a wide (20- to >100-fold) interindividual variation in CYP2A6 expression and activity, which is due primarily to genetic polymorphisms in the CYP2A6 gene, but CYP2A6 activity is also modified by certain drugs and pathological and environmental factors. To date, more than 36 variant alleles (*1B through *37) of the CYP2A6 gene have been identified. There have been 278 SNPs found in the CYP2A6 upstream sequence, 8 introns and 9 exons in NCBI dbSNP. Polymorphism of CYP2A6 has been associated with smoking behavior, drug clearance and lung cancer risk. Further studies are warranted to explore the role of CYP2A6 in clinical practice, drug development and toxicology.

Prediction of deleterious non-synonymous single-nucleotide polymorphisms of human uridine diphosphate glucuronosyltransferase genes

UDP glucuronosyltransferases (UGTs) are an important class of Phase II enzymes involved in the metabolism and detoxification of numerous xenobiotics including therapeutic drugs and endogenous compounds (e.g. bilirubin). To date, there are 21 human UGT genes identified, and most of them contain single-nucleotide polymorphisms (SNPs). Non-synonymous SNPs (nsSNPs) of the human UGT genes may cause absent or reduced enzyme activity and polymorphisms of UGT have been found to be closely related to altered drug clearance and/or drug response, hyperbilirubinemia, Gilbert's syndrome, and Crigler-Najjar syndrome. However, it is unlikely to study the functional impact of all identified nsSNPs in humans using laboratory approach due to its giant number. We have investigated the potential for bioinformatics approach for the prediction of phenotype based on known nsSNPs. We have identified a total of 248 nsSNPs from human UGT genes. The two algorithms tools, sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), were used to predict the impact of these nsSNPs on protein function. SIFT classified 35.5% of the UGT nsSNPs as "deleterious"; while PolyPhen identified 46.0% of the UGT nsSNPs as "potentially damaging" and "damaging". The results from the two algorithms were highly associated. Among 63 functionally characterized nsSNPs in the UGTs, 24 showed altered enzyme expression/activities and 45 were associated with disease susceptibility. SIFT and Polyphen had a correct prediction rate of 57.1% and 66.7%, respectively. These findings demonstrate the potential use of bioinformatics techniques to predict genotype-phenotype relationships which may constitute the basis for future functional studies.

Substrates and inhibitors of human multidrug resistance associated proteins and the implications in drug development

Human contains 49 ATP-binding cassette (ABC) transporter genes and the multidrug resistance associated proteins (MRP1/ABCC1, MRP2/ABCC2, MRP3/ABCC3, MRP4/ABCC4, MRP5/ABCC5, MRP6/ABCC6, MRP7/ABCC10, MRP8/ABCC11 and MRP9/ABCC12) belong to the ABCC family which contains 13 members. ABCC7 is cystic fibrosis transmembrane conductance regulator; ABCC8 and ABCC9 are the sulfonylurea receptors which constitute the ATP-sensing subunits of a complex potassium channel. MRP10/ABCC13 is clearly a pseudo-gene which encodes a truncated protein that is highly expressed in fetal human liver with the highest similarity to MRP2/ABCC2 but without transporting activity. These transporters are localized to the apical and/or basolateral membrane of the hepatocytes, enterocytes, renal proximal tubule cells and endothelial cells of the blood-brain barrier. MRP/ABCC members transport a structurally diverse array of important endogenous substances and xenobiotics and their metabolites (in particular conjugates) with different substrate specificity and transport kinetics. The human MRP/ABCC transporters except MRP9/ABCC12 are all able to transport organic anions, such as drugs conjugated to glutathione, sulphate or glucuronate. In addition, selected MRP/ABCC members may transport a variety of endogenous compounds, such as leukotriene C(4) (LTC(4) by MRP1/ABCC1), bilirubin glucuronides (MRP2/ABCC2, and MRP3/ABCC3), prostaglandins E1 and E2 (MRP4/ABCC4), cGMP (MRP4/ABCC4, MRP5/ABCC5, and MRP8/ABCC11), and several glucuronosyl-, or sulfatidyl steroids. In vitro, the MRP/ABCC transporters can collectively confer resistance to natural product anticancer drugs and their conjugated metabolites, platinum compounds, folate antimetabolites, nucleoside and nucleotide analogs, arsenical and antimonial oxyanions, peptide-based agents, and in concert with alterations in phase II conjugating or biosynthetic enzymes, classical alkylating agents, alkylating agents. Several MRP/ABCC members (MRPs 1-3) are associated with tumor resistance which is often caused by an increased efflux and decreased intracellular accumulation of natural product anticancer drugs and other anticancer agents. Drug targeting of these transporters to overcome MRP/ABCC-mediated multidrug resistance may play a role in cancer chemotherapy. Most MRP/ABCC transporters are subject to inhibition by a variety of compounds. Based on currently available preclinical and limited clinical data, it can be expected that modulation of MRP members may represent a useful approach in the management of anticancer and antimicrobial drug resistance and possibly of inflammatory diseases and other diseases. A better understanding of their substrates and inhibitors has important implications in development of drugs for treatment of cancer and inflammation.

Clinical drugs that interact with St. John's wort and implication in drug development

St. John's wort (Hypericum perforatum, SJW) is one of the most commonly used herbal antidepressants for the treatment of minor to moderate depression. A major safety concern about SJW is its ability to alter the pharmacokinetics and/or clinical response of a variety of clinically important drugs that have distinctive chemical structure, mechanism of action and metabolic pathways. This review highlights and updates the knowledge on clinical interactions of prescribed drugs with SJW and the implication in drug development. A number of clinically significant interactions of SJW have been identified with conventional drugs, including anticancer agents (imatinib and irinotecan), anti-HIV agents (e.g. indinavir, lamivudine and nevirapine), anti-inflammatory agents (e.g. ibuprofen and fexofenadine), antimicrobial agents (e.g. erythromycin and voriconazole), cardiovascular drugs (e.g. digoxin, ivabradine, warfarin, verapamil, nifedipine and talinolol), central nervous system agents (e.g. amitriptyline, buspirone, phenytoin, methadone, midazolam, alprazolam, and sertraline), hypoglycaemic agents (e.g. tolbutamide and gliclazide), immuno-modulating agents (e.g. cyclosporine and tacrolimus), oral contraceptives, proton pump inhibitor (e.g. omeprazole), respiratory system agent (e.g. theophylline), statins (e.g. atorvastatin and pravastatin). Both pharmacokinetic and pharmacodynamic components may play a role in the interactions of drugs with SJW. For pharmacokinetic changes of drugs by SJW, induction of cytochrome P450s (e.g. CYP2C9 and 3A4) and P-glycoprotein (P-gp) are considered the major mechanism. Thus, it is not a surprise that many drugs that interact with SJW are substrates of CYP3A4, CYP2C9 and P-gp. A comprehensive understanding of clinical drugs that interact with SJW has important implications in drug development. New drugs may be designed to minimize interactions with SJW; and new SJW formulations may be designed to avoid drug interactions. Further clinical and mechanistic studies are warranted to explore the interaction of SJW with other important drugs and the potential clinical impact.

Suppression of c-myc expression and c-Myc function in response to sustained DNA damage in MCF-7 breast tumor cells

The topoisomerase II inhibitors teniposide (VM-26), doxorubicin, and amsacrine (m-AMSA), as well as ionizing radiation, induce a transient suppression of c-myc mRNA, which correlates with growth inhibition of MCF-7 breast tumor cells. To further assess the involvement of c-mvc in the DNA damage-induced signal transduction pathways of the breast tumor cell, we determined the influence of sustained DNA damage on c-myc expression, c-Myc protein levels and c-Myc function. Continuous exposure of MCF-7 breast tumor cells to VM-26 induced DNA strand breaks that were sustained for at least 9 hr. DNA strand breakage was accompanied by a decline in c-myc transcripts and c-Myc protein levels by >90% after VM-26 exposure for 24 hr. The activity of a transcriptional target of the c-Myc protein, ornithine decarboxylase, was reduced by approximately 75% within 9 hr of DNA damage, in parallel to the declines in c-myc mRNA and protein levels. Extended exposure to VM-26 resulted in an initial loss of approximately 35% of the cell population followed by the death of additional cells such that by 72 hr only 50% of the cells were viable. Although apoptosis was evident 72 hr after initiating drug exposure [based on cell cycle analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, and an assessment of cell morphology], the primary phase of cell killing, which occurred during the first 24 hr was non-apoptotic. These studies indicate that non-apoptotic pathways can also mediate cell death in the breast tumor cell and support the role of c-myc expression, c-Myc protein, and c-Myc function as elements of the DNA damage response pathway in the breast tumor cell.

Rb dephosphorylation and suppression of E2F activity in human breast tumor cells exposed to a pharmacological concentration of estradiol

This report characterizes the influence of a pharmacological concentration of estradiol on growth arrest and cell death in MCF-7 breast tumor cells, with a focus on elements of the Rb-E2F cell-cycle regulatory pathway. Continuous exposure of MCF-7 breast tumor cells to 100 microM estradiol produces a marked reduction in the G1 and S phase populations and a corresponding increase in the G2/M population within 24 h; after 48 h, accumulation of cells in G1 becomes evident while after 72 h the cells appear to be equally distributed between the G1 and G2/M phases. The accumulation of cells in G1 is temporally associated with dephosphorylation of the Rb protein and suppression of E2F activity. Estradiol also produces an initial burst of cell death with loss of approximately 40% of the tumor cell population within 24 h; however, there is no tangible evidence for the occurrence of apoptosis based on terminal transferase end-labeling of DNA, DNA fragmentation analysis by alkaline unwinding, cell-cycle analysis or cell morphology. In addition to the lack of caspase-3 in MCF-7 cells, the absence of apoptosis could be related, at least in part, to the fact that estradiol promotes a rapid reduction in levels of the E2F-1 and Myc proteins. Overall, these studies are consistent with the concept that alterations in the levels and/or activity of the E2F family of proteins as well as proteins interacting with the E2F family may influence the nature of the antiproliferative and cytotoxic responses of the breast tumor cell.

Influence of ionizing radiation on proliferation, c-myc expression and the induction of apoptotic cell death in two breast tumour cell lines differing in p53 status

PURPOSE

To determine the capacity of ionizing radiation to inhibit proliferation, to suppress c-myc expression and to induce apoptotic cell death in the p53 wild-type MCF-7 cell line and the p53 mutated MDA-MB231 cell line.

MATERIALS AND METHODS

Growth inhibition and cell killing were determined by cell number and trypan blue exclusion. Apoptosis was assessed through cell morphology and fluorescent end-labelling. c-myc expression was monitored by Northern blotting.

RESULTS

Inhibition of cell proliferation by ionizing radiation was similar in both cell lines. MDA-MB231 cells accumulated in G2 while MCF-7 cells accumulated in both the G1 and G2 phases of the cell cycle after irradiation. There was no evidence of apoptosis in either cell line. In MCF-7 cells, growth inhibition correlated closely with an early dose-dependent suppression of c-myc expression; in MDA-MB231 cells, there was no correspondence between growth inhibition and a transient, dose-independent reduction in c-myc message.

CONCLUSIONS

These findings suggest that in the absence of classical apoptotic cell death, radiosensitivity is not predictably related to the p53 status of the cell. While both p53 and c-myc may be linked to the DNA damage response pathway, neither p53 nor c-myc are essential for growth arrest in response to ionizing radiation.