Chest ultrasonography versus supine chest radiography for diagnosis of pneumothorax in trauma patients in the emergency department.

BACKGROUND: Chest X-ray (CXR) is a longstanding method for the diagnosis of pneumothorax but chest ultrasonography (CUS) may be a safer, more rapid, and more accurate modality in trauma patients at the bedside that does not expose the patient to ionizing radiation. This may lead to improved and expedited management of traumatic pneumothorax and improved patient safety and clinical outcomes. OBJECTIVES: To compare the diagnostic accuracy of chest ultrasonography (CUS) by frontline non-radiologist physicians versus chest X-ray (CXR) for diagnosis of pneumothorax in trauma patients in the emergency department (ED). To investigate the effects of potential sources of heterogeneity such as type of CUS operator (frontline non-radiologist physicians), type of trauma (blunt vs penetrating), and type of US probe on test accuracy. SEARCH METHODS: We conducted a comprehensive search of the following electronic databases from database inception to 10 April 2020: Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus, Database of Abstracts of Reviews of Effects, Web of Science Core Collection and Clinicaltrials.gov. We handsearched reference lists of included articles and reviews retrieved via electronic searching; and we carried out forward citation searching of relevant articles in Google Scholar and looked at the "Related articles" on PubMed. SELECTION CRITERIA: We included prospective, paired comparative accuracy studies comparing CUS performed by frontline non-radiologist physicians to supine CXR in trauma patients in the emergency department (ED) suspected of having pneumothorax, and with computed tomography (CT) of the chest or tube thoracostomy as the reference standard. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from each included study using a data extraction form. We included studies using patients as the unit of analysis in the main analysis and we included those using lung fields in the secondary analysis. We performed meta-analyses by using a bivariate model to estimate and compare summary sensitivities and specificities. MAIN RESULTS: We included 13 studies of which nine (410 traumatic pneumothorax patients out of 1271 patients) used patients as the unit of analysis; we thus included them in the primary analysis. The remaining four studies used lung field as the unit of analysis and we included them in the secondary analysis. We judged all studies to be at high or unclear risk of bias in one or more domains, with most studies (11/13, 85%) being judged at high or unclear risk of bias in the patient selection domain. There was substantial heterogeneity in the sensitivity of supine CXR amongst the included studies. In the primary analysis, the summary sensitivity and specificity of CUS were 0.91 (95% confidence interval (CI) 0.85 to 0.94) and 0.99 (95% CI 0.97 to 1.00); and the summary sensitivity and specificity of supine CXR were 0.47 (95% CI 0.31 to 0.63) and 1.00 (95% CI 0.97 to 1.00). There was a significant difference in the sensitivity of CUS compared to CXR with an absolute difference in sensitivity of 0.44 (95% CI 0.27 to 0.61; P < 0.001). In contrast, CUS and CXR had similar specificities: comparing CUS to CXR, the absolute difference in specificity was -0.007 (95% CI -0.018 to 0.005, P = 0.35). The findings imply that in a hypothetical cohort of 100 patients if 30 patients have traumatic pneumothorax (i.e. prevalence of 30%), CUS would miss 3 (95% CI 2 to 4) cases (false negatives) and overdiagnose 1 (95% CI 0 to 2) of those without pneumothorax (false positives); while CXR would miss 16 (95% CI 11 to 21) cases with 0 (95% CI 0 to 2) overdiagnosis of those who do not have pneumothorax. AUTHORS' CONCLUSIONS: The diagnostic accuracy of CUS performed by frontline non-radiologist physicians for the diagnosis of pneumothorax in ED trauma patients is superior to supine CXR, independent of the type of trauma, type of CUS operator, or type of CUS probe used. These findings suggest that CUS for the diagnosis of traumatic pneumothorax should be incorporated into trauma protocols and algorithms in future medical training programmes; and that CUS may beneficially change routine management of trauma.

Aspiration Thrombectomy versus Conventional Catheter-Directed Thrombolysis as First-Line Treatment for Noniatrogenic Acute Lower Limb Ischemia.

PURPOSE: To examine the efficacy, safety, and procedural costs of percutaneous aspiration thrombectomy (PAT) as a first-line treatment for noniatrogenic acute lower limb ischemia (ALI) compared with conventional catheter-directed thrombolysis (CDT). MATERIALS AND METHODS: All patients who underwent endovascular intervention for ALI from January 2015 to August 2017 were included. Fifteen patients were treated with the use of primary PAT and 27 patients were treated with the use of primary CDT. The primary end point was complete thrombus clearance with improvement in Thrombolysis in Myocardial Infarction (TIMI) score. Adjunctive treatment for thrombus removal was considered to indicate technical failure. Treatment of underlying chronic disease was not considered to indicate technical failure. Procedural costs for each patient were calculated by itemizing all disposable equipment, facility overheads, and staff costs. RESULTS: Of the 15 primary PAT patients, technical success was achieved in 8 (53%); the remaining 7 (47%) required adjunctive CDT. Of the 27 primary CDT patients, technical success was achieved in 25 (89%); the remaining 2 (11%) required adjunctive PAT. There were 4 complications in the primary PAT group: 2 were procedure related and of a minor grade. There were 8 complications in the primary CDT group: All were procedure-related, including 2 major groin/retroperitoneal hemorrhage and 1 death from intracranial hemorrhage. Limb salvage was attained in all patients. There were no significant differences in average procedural costs per patient between the 2 groups. CONCLUSIONS: First-line use of PAT for endovascular treatment of ALI can reduce the need for CDT, with no significant cost difference.

Targeted nanoparticle delivery overcomes off-target immunostimulatory effects of oligonucleotides and improves therapeutic efficacy in chronic lymphocytic leukemia.

Several RNA-targeted therapeutics, including antisense oligonucleotides (ONs), small interfering RNAs, and miRNAs, constitute immunostimulatory CpG motifs as an integral part of their design. The limited success with free antisense ONs in hematologic malignancies in recent clinical trials has been attributed to the CpG motif-mediated, TLR-induced prosurvival effects and inefficient target modulation in desired cells. In an attempt to diminish their off-target prosurvival and proinflammatory effects and specific delivery, as a proof of principle, in the present study, we developed an Ab-targeted liposomal delivery strategy using a clinically relevant CD20 Ab (rituximab)-conjugated lipopolyplex nanoparticle (RIT-INP)- and Bcl-2-targeted antisense G3139 as archetypical antisense therapeutics. The adverse immunostimulatory responses were abrogated by selective B cell-targeted delivery and early endosomal compartmentalization of G3139-encapsulated RIT-INPs, resulting in reduced NF-κB activation, robust Bcl-2 down-regulation, and enhanced sensitivity to fludarabine-induced cytotoxicity. Furthermore, significant in vivo therapeutic efficacy was noted after RIT-INP-G3139 administration in a disseminated xenograft leukemia model. The results of the present study demonstrate that CD20-targeted delivery overcomes the immunostimulatory properties of CpG-containing ON therapeutics and improves efficient gene silencing and in vivo therapeutic efficacy for B-cell malignancies. The broader implications of similar approaches in overcoming immunostimulatory properties of RNA-directed therapeutics in hematologic malignancies are also discussed.

CD33-Targeted Lipid Nanoparticles (aCD33LNs) for Therapeutic Delivery of GTI-2040 to Acute Myelogenous Leukemia.

CD33-targeted lipid nanoparticles (aCD33LNs) were synthesized for delivery of GTI-2040, an antisense oligonucleotide (ASO) against the R2 subunit of ribonucleotide reductase, to acute myelogenous leukemia (AML). These LNs incorporated a deoxycholate-polyethylenimine (DOC-PEI) conjugate, which has shown significant activity to facilitate oligonucleotide delivery. Anti-CD33 scFv (aCD33) was added as a targeting ligand. The delivery efficiency of this system was investigated both in vitro and in vivo. When cells were treated with aCD33LN/GTI-2040, significant uptake was observed in CD33 positive Kasumi-1 cells. aCD33LNs loaded with GTI-2040 induced significant down-regulation of R2 mRNA and protein levels in AML cells. Moreover, aCD33LN/GTI-2040 showed a 15-fold reduction in the IC50 of antileukemic drug Ara-C in Kasumi-1 cells. In Kasumi-1 xenograft model, aCD33LN/GTI-2040 showed significant R2 downregulation compared to LN/GTI-2040. Furthermore, aCD33LN/GTI-2040 coadministered with Ara-C was shown to be highly effective in tumor growth inhibition and to greatly increase survival time of mice bearing Kasumi-1 xenograft tumors. The conjugate DOC-PEI has shown an ability to include calcein release from lipid nanoparticles, suggesting a potential mechanism contributing to efficient endosome release by DOC-PEI2K. These results indicate that aCD33LNs are a highly effective vehicle for the therapeutic delivery of antisense agents to AML.

RNA-dependent inhibition of ribonucleotide reductase is a major pathway for 5-azacytidine activity in acute myeloid leukemia.

5-Azacytidine (5-azaC) is an azanucleoside approved for myelodysplastic syndrome. Approximately 80%-90% of 5-azaC is believed to be incorporated into RNA, which disrupts nucleic acid and protein metabolism leading to apoptosis. A smaller fraction (10%-20%) of 5-azaC inhibits DNA methylation and synthesis through conversion to decitabine triphosphate and subsequent DNA incorporation. However, its precise mechanism of action remains unclear. Ribonucleotide reductase (RR) is a highly regulated enzyme comprising 2 subunits, RRM1 and RRM2, that provides the deoxyribonucleotides required for DNA synthesis/repair. In the present study, we found for the first time that 5-azaC is a potent inhibitor of RRM2 in leukemia cell lines, in a mouse model, and in BM mononuclear cells from acute myeloid leukemia (AML) patients. 5-azaC-induced RRM2 gene expression inhibition involves its direct RNA incorporation and an attenuated RRM2 mRNA stability. Therefore, 5-azaC causes a major perturbation of deoxyribonucleotide pools. We also demonstrate herein that the initial RR-mediated 5-azaC conversion to decitabine is terminated through its own inhibition. In conclusion, we identify RRM2 as a novel molecular target of 5-azaC in AML. Our findings provide a basis for its more widespread clinical use either alone or in combination.

Effects of tetrahydrouridine on pharmacokinetics and pharmacodynamics of oral decitabine.

The deoxycytidine analog decitabine (DAC) can deplete DNA methyl-transferase 1 (DNMT1) and thereby modify cellular epigenetics, gene expression, and differentiation. However, a barrier to efficacious and accessible DNMT1-targeted therapy is cytidine deaminase, an enzyme highly expressed in the intestine and liver that rapidly metabolizes DAC into inactive uridine counterparts, severely limiting exposure time and oral bioavailability. In the present study, the effects of tetrahydrouridine (THU), a competitive inhibitor of cytidine deaminase, on the pharmacokinetics and pharmacodynamics of oral DAC were evaluated in mice and nonhuman primates. Oral administration of THU before oral DAC extended DAC absorption time and widened the concentration-time profile, increasing the exposure time for S-phase-specific depletion of DNMT1 without the high peak DAC levels that can cause DNA damage and cytotoxicity. THU also decreased interindividual variability in pharmacokinetics seen with DAC alone. One potential clinical application of DNMT1-targeted therapy is to increase fetal hemoglobin and treat hemoglobinopathy. Oral THU-DAC at a dose that would produce peak DAC concentrations of less than 0.2µM administered 2×/wk for 8 weeks to nonhuman primates was not myelotoxic, hypomethylated DNA in the γ-globin gene promoter, and produced large cumulative increases in fetal hemoglobin. Combining oral THU with oral DAC changes DAC pharmacology in a manner that may facilitate accessible noncytotoxic DNMT1-targeted therapy.

Clinical and pharmacodynamic activity of bortezomib and decitabine in acute myeloid leukemia.

We recently reported promising clinical activity for a 10-day regimen of decitabine in older AML patients; high miR-29b expression associated with clinical response. Subsequent preclinical studies with bortezomib in AML cells have shown drug-induced miR-29b up-regulation, resulting in loss of transcriptional activation for several genes relevant to myeloid leukemogenesis, including DNA methyltransferases and receptor tyrosine kinases. Thus, a phase 1 trial of bortezomib and decitabine was developed. Nineteen poor-risk AML patients (median age 70 years; range, 32-84 years) enrolled. Induction with decitabine (20 mg/m(2) intravenously on days 1-10) plus bortezomib (escalated up to the target 1.3 mg/m(2) on days 5, 8, 12, and 15) was tolerable, but bortezomib-related neuropathy developed after repetitive cycles. Of previously untreated patients (age ≥ 65 years), 5 of 10 had CR (complete remission, n = 4) or incomplete CR (CRi, n = 1); 7 of 19 overall had CR/CRi. Pharmacodynamic analysis showed FLT3 down-regulation on day 26 of cycle 1 (P = .02). Additional mechanistic studies showed that FLT3 down-regulation was due to bortezomib-induced miR-29b up-regulation; this led to SP1 down-regulation and destruction of the SP1/NF-κB complex that transactivated FLT3. This study demonstrates the feasibility and preliminary clinical activity of decitabine plus bortezomib in AML and identifies FLT3 as a novel pharmacodynamic end point for future trials.

First-line beta-blockers versus other antihypertensive medications for chronic type B aortic dissection.

BACKGROUND: Thoracic aortic dissection (TAD) is a severe and often lethal complication in people with hypertension. Current practice in the treatment of chronic type B aortic dissections is the use of beta-blockers as first-line therapy to decrease aortic wall stress. Other antihypertensive medications, such as calcium channel blockers (CCBs), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), have been suggested for the medical therapy of type B TAD. OBJECTIVES: To assess the effects of first-line beta-blockers compared with other first-line antihypertensive drug classes for treating chronic type B TAD. SEARCH METHODS: We searched the Database of Abstracts of Reviews of Effects (DARE) for related reviews. We searched the Hypertension Group Specialised Register (1946 to 26 January 2014), the Cochrane Central Register of Controlled Trials (2014, Issue 1), MEDLINE (1946 to 24 January 2014), MEDLINE In-Process, EMBASE (1974 to 24 January 2014) and ClinicalTrials.gov (to 26 January 2014). SELECTION CRITERIA: We considered randomized controlled trials (RCTs) comparing different antihypertensive medications in the treatment of chronic type B TAD to be eligible for inclusion. Total mortality rate was the primary outcome of this review. Secondary outcomes included total non-fatal adverse events relating to TADs and number of people not requiring surgical treatment. DATA COLLECTION AND ANALYSIS: Two review authors (KC, PL) independently reviewed titles and abstracts and decided on studies to include based on the inclusion criteria. We resolved discrepancies between the two review authors by discussion. MAIN RESULTS: After a thorough review of the search results, we identified no studies that met the inclusion criteria. AUTHORS' CONCLUSIONS: We did not find any RCTs that compared first-line beta-blockers with other first-line antihypertensive medications for the treatment of chronic type B TAD. Therefore, there is no RCT evidence to support the current guidelines recommending the use of beta-blockers. RCTs are required to assess the benefits and harms of beta-blockers and other antihypertensive medications as first-line treatment of chronic type B TAD.

Clinical response and miR-29b predictive significance in older AML patients treated with a 10-day schedule of decitabine.

A phase II clinical trial with single-agent decitabine was conducted in older patients (>or=60 years) with previously untreated acute myeloid leukemia (AML) who were not candidates for or who refused intensive chemotherapy. Subjects received low-dose decitabine at 20 mg/m(2) i.v. over 1 h on days 1 to 10. Fifty-three subjects enrolled with a median age of 74 years (range, 60-85). Nineteen (36%) had antecedent hematologic disorder or therapy-related AML; 16 had complex karyotypes (>or=3 abnormalities). The complete remission rate was 47% (n = 25), achieved after a median of three cycles of therapy. Nine additional subjects had no morphologic evidence of disease with incomplete count recovery, for an overall response rate of 64% (n = 34). Complete remission was achieved in 52% of subjects presenting with normal karyotype and in 50% of those with complex karyotypes. Median overall and disease-free survival durations were 55 and 46 weeks, respectively. Death within 30 days of initiation of treatment occurred in one subject (2%), death within 8 weeks in 15% of subjects. Given the DNA hypomethylating effect of decitabine, we examined the relationship of clinical response and pretreatment level of miR-29b, previously shown to target DNA methyltransferases. Higher levels of miR-29b were associated with clinical response (P = 0.02). In conclusion, this schedule of decitabine was highly active and well tolerated in this poor-risk cohort of older AML patients. Levels of miR-29b should be validated as a predictive factor for stratification of older AML patients to decitabine treatment.

Cytochrome P4501A2 phenotype and bladder cancer risk: The Shanghai bladder cancer study.

Cytochrome P450 1A2 (CYP1A2) is hypothesized to catalyze the activation of arylamines, known human bladder carcinogens present in cigarette smoke. The relationship between CYP1A2 phenotype and bladder cancer risk was examined in a case-control study involving 519 patients and 514 controls in Shanghai, China. Both CYP1A2 and N-acetyltransferase 2 (NAT2) phenotypic status were determined by a caffeine-based urinary assay. Our study showed that among smokers at urine collection, patients with bladder cancer had statistically significantly higher CYP1A2 phenotype scores compared to control subjects (p = 0.001). The odds ratios (95% confidence intervals) of bladder cancer for the second, third and fourth quartiles of the CYP1A2 score were 1.31 (0.53-3.28), 2.04 (0.90-4.60) and 2.82 (1.32-6.05), respectively, relative to the lowest quartile (p for trend = 0.003). NAT2 slow acetylation phenotype was associated with a statistically significant 40% increased risk of bladder cancer, and the relationship was independent of subjects' smoking status. Subjects possessing the NAT2 slow acetylation phenotype and the highest tertile of CYP1A2 scores showed the highest risk for bladder cancer. Their odds ratios (95% confidence intervals) was 2.13 (1.24-3.68) relative to their counterparts possessing the NAT2 rapid acetylation phenotype and the lowest tertile of CYP1A2 scores. The findings of our study demonstrate that CYP1A2 phenotype may be an important contributing factor in the development of smoking-related bladder cancer in humans.

Synthetic microRNA cassette dosing: pharmacokinetics, tissue distribution and bioactivity.

MicroRNAs (miRs) are deregulated in cancer and leukemia. Restoring aberrantly downregulated tumor suppressor miRs or antagonizing overexpressed oncogenic miRs in malignant cells by synthetic RNA oligonucleotides represents a potentially novel therapeutic approach in cancer and leukemia. However, given the complex networking and concurrent deregulation of miRs in malignant cells, an effective approach may require concurrent targeting of multiple miRs. Cassette dosing involves simultaneous administration of a mixture of oligonucleotides from the same or different structural classes. However, information on cassette dosing pharmacokinetics, tissue distribution and bioactivity of synthetic miRs is lacking. In this study, three synthetic 2'-methoxyphosphorothioate-miRs (2'-MeOPSmiR16-1, 2'-MeOPSmiR29b and 2'-MeOPSantagomiR155) were administered iv to C57BL/6 mice as a mixture, each at 7.5 mg/kg. Analysis of concentrations of individual miR in plasma and major organ tissues (bone marrow, spleen, liver, brain, heart, kidney and lung) was performed. The mRNA and protein levels of miR's biotargets were monitored sequentially after dosing up to 24 h. Our results demonstrated that these synthetic miRs retain their different individual pharmacokinetic properties and all display three-compartmental pharmacokinetics. 2'-MeOPSmiR16-1 has the longest plasma gamma half-life of 2508 min and lowest total body clearance of 0.0054 L/min·kg, whereas 2'-MeOPSmiR29b has the shortest gamma half-life of 510.6 min and highest total body clearance of 0.042 L/min·kg. The tissue concentrations of all three 2'-MeOPS-modified miR(s)/antagomiR were measurable from 5 min to at least 24 h after dosing, indicating that these concurrently delivered oligonucleotides can reach organ tissues. Importantly, there were biological activities of the concurrently administered miRs which persisted, as shown by the downregulation of specific targets in tested tissues, albeit with variations. Brain was one of the most sensitive tissues with respect to downregulation of mRNA and protein levels of four measured biotargets (e.g., Bcl-2, Mcl-1, DNMT3a and DNMT3b) despite its relatively low miR/antagomiRs levels. We conclude that cassette dosing is applicable to 2'-MeOPS-modified synthetic miRs that are tissue-deliverable and biofunctional without any additional formulation requirement. This study supports future exploration of miR-involved combination therapies.

Reactivation of RASSF1A in breast cancer cells by curcumin.

Reactivation of tumor suppressor genes (TSGs) involved in carcinogenesis by nontoxic bioactive food component represents a promising strategy for cancer chemoprevention. Recently, curcumin has been demonstrated to inhibit a bacterial DNA methyltransferase (M. Sss I) activity, induce global DNA hypomethylation in leukemia cells, and reactivate several hypermethylation silenced genes in lung and prostate cancer cells. Herein, we demonstrated that curcumin can enhance the mRNA and protein levels of ras-association domain family protein 1A (RASSF1A), 1 hypermethylation-silenced TSG, and decrease its promoter methylation in breast cancer cells. Mechanistic study demonstrated that curcumin can decrease DNA methylation activity of nuclear extract and downregulate the mRNA and protein levels of DNMT1 in MCF-7 cells, which may be associated with curcumin-induced disruption of NF-κB/Sp1 complex bound to the promoter region of DNMT1. Altogether, this study reveals a novel molecular mechanism of curcumin as a chemo-preventive agent for breast cancer through hypomethylation reactivation of RASSF1A.

Alveolar soft part sarcoma in a young woman: A case report from Hong Kong.

Alveolar soft part sarcoma (ASPS) is a rare, highly vascular, deep soft tissue mesenchymal malignancy that is classically seen in the lower extremities of young adults. We reported a case of a 32-year-old young Chinese woman in Hong Kong with a biopsy-proven alveolar soft part sarcoma. The condition can be suggested by classical features using contrast-enhanced CT scans and MRIs or confirmed by image-guided biopsies. Early recognition of the condition is important due to its poor prognosis and lack of awareness. The mainstay of treatment for ASPS is complete surgical resection of the primary tumor and radiotherapy for microscopic residual disease at the primary site, or chemotherapy in special cases.

Phase I trial of low dose decitabine targeting DNA hypermethylation in patients with chronic lymphocytic leukaemia and non-Hodgkin lymphoma: dose-limiting myelosuppression without evidence of DNA hypomethylation.

Targeting aberrant DNA hypermethylation in chronic lymphocytic leukaemia (CLL) and non-Hodgkin lymphoma (NHL) with decitabine may reverse epigenetic silencing in B-cell malignancies. Twenty patients were enrolled in two phase I trials to determine the minimum effective pharmacological dose of decitabine in patients with relapsed/refractory CLL (n = 16) and NHL (n = 4). Patients received 1-3 cycles of decitabine. Dose-limiting toxicity (DLT) was observed in 2 of 4 CLL and 2 of 2 NHL patients receiving decitabine at 15 mg/m(2) per d days 1-10, consisting of grade 3-4 thrombocytopenia and hyperbilirubinaemia. Six patients with CLL received decitabine at 10 mg/m(2) per d days 1-10 without DLT; however, re-expression of methylated genes or changes in global DNA methylation were not observed. Therefore, a 5-day decitabine schedule was examined. With 15 mg/m(2) per d decitabine days 1-5, DLT occurred in 2 of 6 CLL and 2 of 2 NHL patients, consisting of grade 3-4 neutropenia, thrombocytopenia, and febrile neutropenia. Eight patients had stable disease. In 17 patients, there were no significant changes in genome-wide methylation or in target gene re-expression. In conclusion, dose-limiting myelosuppression and infectious complications prevented dose escalation of decitabine to levels associated with changes in global methylation or gene re-expression in CLL and NHL.

Targeted delivery of antisense oligodeoxynucleotide by transferrin conjugated pH-sensitive lipopolyplex nanoparticles: a novel oligonucleotide-based therapeutic strategy in acute myeloid leukemia.

Therapeutic use of oligodeoxynucleotides (ODNs) that hybridize to and downregulate target mRNAs encoding proteins that contribute to malignant transformation has a sound rationale, but has had an overall limited clinical success in cancer due to insufficient intracellular delivery. Here we report a development of formulations capable of promoting targeted delivery and enhanced pharmacologic activity of ODNs in acute myeloid leukemia (AML) cell lines and patient primary cells. In this study, transferrin (Tf) conjugated pH-sensitive lipopolyplex nanoparticles (LPs) were prepared to deliver GTI-2040, an antisense ODN against the R2 subunit of ribonucleotide reductase that has been shown to contribute to chemoresistance in AML. LPs had an average particle size around 110 nm and a moderately positive zeta potential at approximately 10 mV. The ODN encapsulation efficiency of LPs was >90%. These nanoparticles could release ODNs at acidic endosomal pH and facilitate the cytoplasmic delivery of ODNs after endocytosis. In addition, Tf-mediated targeted delivery of GTI-2040 was achieved. R2 downregulation at both mRNA and protein levels was improved by 8-fold in Kasumi-1 cells and 2- to 20-fold in AML patient primary cells treated with GTI-2040-Tf-LPs, compared to free GTI-2040 treatment. Moreover, Tf-LPs were more effective than nontargeted LPs, with 10 to 100% improvement at various concentrations in Kasumi-1 cells and an average of 45% improvement at 3 microM concentration in AML patient primary cells. Treatment with 1 microM GTI-2040-Tf-LPs sensitized AML cells to the chemotherapy agent cytarabine, by decreasing its IC(50) value from 47.69 nM to 9.05 nM. This study suggests that the combination of pH sensitive LP formulation and Tf mediated targeting is a promising strategy for antisense ODN delivery in leukemia therapy.

A sensitive and specific liquid chromatography/tandem mass spectrometry method for quantification of nevirapine and its five metabolites and their pharmacokinetics in baboons.

A highly sensitive and specific LC-MS/MS assay was developed and validated to quantify nevirapine (NVP) and its five metabolites [2-, 3-, 8-, 12-hydroxyl NVP (OHNVP) and 4-carboxyl NVP (CANVP)] simultaneously in baboon serum and the assay was used to characterize their pharmacokinetic studies of an oral-dose escalation study in baboon. The lower limit of quantification (LLOQ) for NVP and its four hydroxyl nevirapine metabolites was 1.0 ng/mL and for 4-CANVP was 5.0 ng/mL. The between-run and within-run precisions and accuracies at four quality control concentrations (1, 5, 50 and 500 ng/mL) were evaluated in baboon serum with less than 14% variation and 93-114% accuracies (n = 6), except for the LLOQ for 2-OHNVP, which had an accuracy of 115.8% for between-run validation. The pharmacokinetics of NVP and its five metabolites in non-pregnant baboons by a single-dose escalation study were also profiled. The major metabolites detected were 4-CANVP and 12-OHNVP. 3-OHNVP and 2-OHNVP were the minor metabolites with only a trace amount of 2-OHNVP detected in some pharmacokinetic samples. No 8-OHNVP was observed in all of the pharmacokinetic samples. In addition, the fragmentation for the four hydroxyl metabolite isomers is also discussed.

Modulation of DNA methylation by a sesquiterpene lactone parthenolide.

Hypermethylation of 5'-cytosine-guanosine islands of tumor suppressor genes resulting in their silencing has been proposed to be a hallmark of various tumors. Modulation of DNA methylation with DNA methylation inhibitors has been shown to result in cancer cell differentiation or apoptosis and represents a novel strategy for chemotherapy. Currently, effective DNA methylation inhibitors are mainly limited to decitabine and 5-azacytidine, which still show unfavorable toxicity profiles in the clinical setting. Thus, discovery and development of novel hypomethylating agents, with a more favorable toxicity profile, is essential to broaden the spectrum of epigenetic therapy. Parthenolide, the principal bioactive sesquiterpene lactone of feverfew, has been shown to alkylate Cys(38) of p65 to inhibit nuclear factor-kappaB activation and exhibit anti-tumor activity in human malignancies. In this article, we report that parthenolide 1) inhibits DNA methyltransferase 1 (DNMT1) with an IC(50) of 3.5 microM, possibly through alkylation of the proximal thiolate of Cys(1226) of the catalytic domain by its gamma-methylene lactone, and 2) down-regulates DNMT1 expression possibly associated with its SubG(1) cell-cycle arrest or the interruption of transcriptional factor Sp1 binding to the promoter of DNMT1. These dual functions of parthenolide result in the observed in vitro and in vivo global DNA hypomethylation. Furthermore, parthenolide has been shown to reactivate tumor suppressor HIN-1 gene in vitro possibly associated with its promoter hypomethylation. Hence, our study established parthenolide as an effective DNA methylation inhibitor, representing a novel prototype for DNMT1 inhibitor discovery and development from natural structural-diversified sesquiterpene lactones.

Quantification of regional DNA methylation by liquid chromatography/tandem mass spectrometry.

Promoter hypermethylation-associated tumor suppressor gene (TSG) silencing has been explored as a therapeutic target for hypomethylating agents. Promoter methylation change may serve as a pharmacodynamic endpoint for evaluation of the efficacy of these agents and predict the patient's clinical response. Here a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been developed for quantitative regional DNA methylation analysis using the molar ratio of 5-methyl-2'-deoxycytidine (5mdC) to 2'-deoxycytidine (2dC) in the enzymatic hydrolysate of fully methylated bisulfite-converted polymerase chain reaction (PCR) amplicons as the methylation indicator. The assay can differentiate 5% of promoter methylation level with an intraday precision ranging from 3 to 16% using two TSGs: HIN-1 and RASSF1A. This method was applied to characterize decitabine-induced promoter DNA methylation changes of these two TSGs in a breast cancer MCF-7 cell line. Promoter methylation of these TSGs was found to decrease in a dose-dependent manner. Correspondingly, the expression of these TSGs was enhanced. The sensitivity and reproducibility of the method make it a valuable tool for specific gene methylation analysis that could aid characterization of hypomethylating activity on specific genes by hypomethylating agents in a clinical setting.

A LC-MS/MS method for the analysis of intracellular nucleoside triphosphate levels.

PURPOSE: To simultaneously quantify intracellular nucleoside triphosphate (NTP) and deoxynucleoside triphosphate (dNTP) pools and to assess their changes produced by interfering with ribonucleotide reductase (RNR) expression in leukemia cells. METHODS: A HPLC-MS/MS system was used to quantify intracellular NTP and dNTP pools. RESULTS: The assay was linear between 50 nM, the lower limit of quantification (LLOQ), and 10 muM in cell lysate. The within-day coefficients of variation (CVs, n = 5) were found to be 12.0-18.0% at the LLOQ and 3.0-9.0% between 500 and 5,000 nM for dNTPs and 8.0-15.0% and 2.0-6.0% for NTPs. The between-day CVs (n = 5) were 9.0-13.0% and 3.0-11.0% for dNTPs and 9.0-13.0% and 3.0-6.0% for NTPs. The within-day accuracy values were 93.0-119.0% for both NTPs and dNTPs. ATP overlapped with dGTP and they were analyzed as a composite. This method was applied to measure basal intracellular dNTPs/NTPs in five leukemia cell lines exposed to the RNR antisense GTI-2040. Following drug treatment, dCTP and dATP levels were found to decrease significantly in MV4-11 and K562 cells. Additionally, perturbation of dNTP/NTP levels in bone marrow sample of a patient treated with GTI-2040 was detected. CONCLUSIONS: This method provides a practical tool to measure intracellular dNTP/NTP levels in cells and clinical samples.

Curcumin is a potent DNA hypomethylation agent.

Molecular docking of the interaction of curcumin and DNMT1 suggested that curcumin covalently blocks the catalytic thiolate of C1226 of DNMT1 to exert its inhibitory effect. This was validated by showing that curcumin inhibits the activity of M. SssI with an IC(50) of 30 nM, but no inhibitory activity of hexahydrocurcumin up to 100 microM. In addition, curcumin can induce global DNA hypomethylation in a leukemia cell line.