PTPRO represses ERBB2-driven breast oncogenesis by dephosphorylation and endosomal internalization of ERBB2.

The plasma membrane-associated tyrosine phosphatase PTPRO is frequently transcriptionally repressed in cancers and signifies poor prognosis of breast cancer patients. In this study, deletion of Ptpro in MMTV-Erbb2 transgenic mice dramatically shortened the mammary tumor latency and accelerated tumor growth due to loss of Ptpro within the breast cancer cells but not in surrounding tissue as confirmed by hetero-transplantation studies. Both in vitro and in vivo data demonstrated that the phosphatase activity was required for the inactivation of ERBB2 and its downstream signaling. PTPRO regulated the phosphorylation status of ERBB2 at Y1248. Co-immunoprecipitation and proximity ligation assay (Duolink) indicated that PTPRO directly physically interacted with ERBB2. Moreover, PTPRO phosphatase activity shortened the half-life of ERBB2 by increasing endocytotic degradation. PTPRO reexpression by demethylation treatment using 5-azacytidine reduced the proliferation and colony formation potential in ERBB2-positive breast cancer cells. Taken together, PTPRO inhibited ERBB2-driven breast cancer through dephosphorylation leading to dual effects of ERBB2 signaling suppression and endosomal internalization of ERBB2, Therefore, reexpression of PTPRO may be a potential therapy for ERBB2-overexpressing breast cancer.

Cellular and Kaposi's sarcoma-associated herpes virus microRNAs in sepsis and surgical trauma.

Once a patient is in septic shock, survival rates drop by 7.6% for every hour of delay in antibiotic therapy. Biomarkers based on the molecular mechanism of sepsis are important for timely diagnosis and triage. Here, we study the potential roles of a panel of cellular and viral miRNAs as sepsis biomarkers. We performed genome-wide microRNA (miRNA) expression profiling in leukocytes from septic patients and nonseptic controls, combined with quantitative RT-PCR in plasmas from two cohorts of septic patients, two cohorts of nonseptic surgical patients and healthy volunteers. Enzyme-linked immunosorbent assay, miRNA transfection and chromatin immunoprecipitation were used to study the effects of Kaposi sarcoma herpes virus (KSHV) miRNAs on interleukin's secretion. Differences related to sepsis etiology were noted for plasma levels of 10 cellular and 2 KSHV miRNAs (miR-K-10b and miR-K-12-12*) between septic and nonseptic patients. All the sepsis groups had high KSHV miRNAs levels compared with controls; Afro-American patients had higher levels of KSHV-miR-K12-12* than non-Afro-American patients. Both KSHV miRNAs were increased on postoperative day 1, but returned to baseline on day 7; they acted as direct agonists of Toll-like receptor 8 (TLR8), which might explain the increased secretion of the IL-6 and IL-10. Cellular and KSHV miRNAs are differentially expressed in sepsis and early postsurgical patients and may be exploited for diagnostic and therapeutic purposes. Increased miR-K-10b and miR-K12-12* are functionally involved in sepsis as agonists of TLR8, forming a positive feedback that may lead to cytokine dysregulation.

The association of diabetes and anti-diabetic medications with clinical outcomes in multiple myeloma.

BACKGROUND: Insulin/insulin-like growth factor-1 signalling may underlie the promoting effect of type 2 diabetes on cancer. This study examined the association of diabetes, including steroid-induced diabetes (SID), and the impact of anti-diabetic medication on clinical outcomes of multiple myeloma (MM). METHODS: A retrospective review was conducted of 1240 MM patients. Overall survival (OS) and MM disease status prior to death were analysed. RESULTS: Diabetic patients had a significantly shorter OS than non-diabetic patients (median: 65.4 vs 98.7 months). In multivariate analysis, SID was a significant predictor of decreased OS, along with age, comorbidity, MM stage, and cytogenetic abnormalities. Analyzing only the diabetic MM patients, Cox regression showed that metformin predicted an increased OS, whereas use of insulin/analogues predicted a decreased OS. Competing risk analysis showed that DM was associated with increased cumulative incidence of death with progressive MM. Among the diabetics, multivariate regression showed that insulin/analogues were associated with increased, but metformin with decreased death with progressive MM. Potential immortal time bias was evaluated by landmark analyses. CONCLUSIONS: DM, SID in particular, is associated with poor clinical outcomes in MM. Insulin/analogues are associated with poor outcomes, whereas metformin is associated with improved outcomes. No conclusion about causal relationships can be made at this time. Managing hyperglycaemia with non-insulin regimens should be investigated in randomised trials.

Metformin promotes autophagy and apoptosis in esophageal squamous cell carcinoma by downregulating Stat3 signaling.

The antidiabetic drug metformin exerts chemopreventive and antineoplastic effects in many types of malignancies. However, the mechanisms responsible for metformin actions appear diverse and may differ in different types of cancer. Understanding the molecular and cellular mechanisms specific for different cancers is important to optimize strategy for metformin treatment in different cancer types. Here, we investigate the in vitro and in vivo effects of metformin on esophageal squamous cell carcinoma (ESCC) cells. Metformin selectively inhibited cell growth in ESCC tumor cells but not immortalized noncancerous esophageal epithelial cells. In addition to apoptosis, metformin triggered autophagy. Pharmacological or genetic inhibition of autophagy sensitized ESCC cells to metformin-induced apoptotic cell death. Mechanistically, signal transducer and activator of transcription 3 (Stat3) and its downstream target Bcl-2 was inactivated by metformin treatment. Accordingly, small interfering RNA (siRNA)-mediated Stat3 knockdown enhanced metformin-induced autophagy and apoptosis, and concomitantly enhanced the inhibitory effect of metformin on cell viability. Similarly, the Bcl-2 proto-oncogene, an inhibitor of both apoptosis and autophagy, was repressed by metformin. Ectopic expression of Bcl-2 protected cells from metformin-mediated autophagy and apoptosis. In vivo, metformin downregulated Stat3 activity and Bcl-2 expression, induced apoptosis and autophagy, and inhibited tumor growth. Together, inactivation of Stat3-Bcl-2 pathway contributes to metformin-induced growth inhibition of ESCC by facilitating crosstalk between apoptosis and autophagy.

Metformin and thiazolidinediones are associated with improved breast cancer-specific survival of diabetic women with HER2+ breast cancer.

BACKGROUND: Insulin/insulin-like growth factor-I (IGF-I) signaling is a mechanism mediating the promoting effect of type 2 diabetes (DM2) on cancer. Human epidermal growth factor receptor (HER2), insulin receptor and IGF-I receptor involve the same PI3K/AKT/mTOR signaling, and different antidiabetic pharmacotherapy may differentially affect this pathway, leading to different prognoses of HER2+ breast cancer. METHODS: We reviewed 1983 consecutive patients with HER2+ breast cancer treated between 1 January 1998 and 30 September 2010. The overall survival, breast cancer-specific death rate, age, race, nuclear grade, stage, menopausal status, estrogen and progesterone receptor status, body mass index and classes of antidiabetic pharmacotherapy were analyzed. RESULTS: A Cox regression analysis showed that DM2 [P=0.026, hazard ratio (HR)=1.42, 95 % confidence interval (95 % CI) 1.04-1.94] predicted poor survival of stage≥2 HER2+ breast cancer. In Kaplan-Meier analysis, metformin predicted lengthened survival and so did thiazolidinediones. Analyzing only the diabetics, Cox regression showed that metformin (P=0.041, HR=0.52, 95 % CI 0.28-0.97) and thiazolidinediones (P=0.036; HR=0.41, 95% CI 0.18-0.93) predicted lengthened survival, and competing risk analysis showed that metformin and thiazolidinediones were associated with decreased breast cancer-specific mortality (P=0.023, HR=0.47, 95% CI 0.24-0.90 and P=0.044, HR=0.42, 95 % CI 0.18-0.98, respectively). CONCLUSIONS: Thiazolidinediones and metformin users are associated with better clinical outcomes than nonusers in diabetics with stage≥2 HER2+ breast cancer. The choice of antidiabetic pharmacotherapy may influence prognosis of this group.

COP9 signalosome subunit 6 stabilizes COP1, which functions as an E3 ubiquitin ligase for 14-3-3σ.

14-3-3σ, a gene upregulated by p53 in response to DNA damage, exists as part of a positive-feedback loop, which activates p53 and is a human cancer epithelial marker downregulated in various cancer types. 14-3-3σ levels are critical for maintaining p53 activity in response to DNA damage and regulating signal mediators such as Akt. In this study, we identify mammalian constitutive photomorphogenic 1 (COP1) as a novel E3 ubiquitin ligase for targeting 14-3-3σ through proteasomal degradation. We show for the first time that COP9 signalosome subunit 6 (CSN6) associates with COP1 and is involved in 14-3-3σ ubiquitin-mediated degradation. Mechanistic studies show that CSN6 expression leads to stabilization of COP1 through reducing COP1 self-ubiquitination and decelerating COP1's turnover rate. We also show that CSN6-mediated 14-3-3σ ubiquitination is compromised when COP1 is knocked down. Thus, CSN6 mediates 14-3-3σ ubiquitination through enhancing COP1 stability. Subsequently, we show that CSN6 causes 14-3-3σ downregulation, thereby activating Akt and promoting cell survival. Also, CSN6 overexpression leads to increased cell growth, transformation and promotes tumorigenicity. Significantly, 14-3-3σ expression can correct the abnormalities mediated by CSN6 expression. These data suggest that the CSN6-COP1 axis is involved in 14-3-3σ degradation, and that deregulation of this axis will promote cell growth and tumorigenicity.

Thiazolidinediones and metformin associated with improved survival of diabetic prostate cancer patients.

BACKGROUND: The association between antidiabetic medications and the prognosis of human prostate cancer has not been explored. This study examined the impact of these drugs on the outcomes of diabetic patients with prostate cancer to provide a basis for diabetes management strategy in these patients. PATIENTS AND METHODS: Records of consecutive prostate cancer patients with coexisting diabetes mellitus type 2 who were treated at the study institution between 15 July 1999 and 31 December 2008 were reviewed. The survival, cancer pathological grade, stage at the time of diagnosis, and antidiabetic pharmacotherapy of the patients were analyzed. RESULTS: A total of 233 consecutive cases were analyzed. In Kaplan-Meier analysis, thiazolidinedione (log-rank, P = 0.005) and metformin (log-rank, P = 0.035) usage were significant predictors of improved overall survival, while insulin and insulin secretagogue usage were not significant predictors. Multivariate Cox regression analysis showed that thiazolidinedione {hazard ratio [HR] = 0.454 [95% confidence interval (CI) 0.213-0.965], P = 0.040} and metformin [HR = 0.550 (95% CI 0.315-0.960), P = 0.035] usage remained as significant predictors of favorable survival after controlling for variables including age, race, Gleason grade, and stage. CONCLUSIONS: Thiazolidinediones and metformin appear to be associated with improved overall survival of diabetic prostate cancer patients. The choice of antidiabetic pharmacotherapy may influence overall survival of these patients.

Bone mineral density enhances use of clinical risk factors in predicting ten-year risk of osteoporotic fractures in Chinese men: the Hong Kong Osteoporosis Study.

UNLABELLED: This prospective study aimed to determine the risk factors and the 10-year probability of osteoporotic fracture in Southern Chinese men. The findings show substantial population differences in fracture incidence and risk prediction compared to the FRAX(TM) model, and the addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men. INTRODUCTION: Clinical risk factors with or without bone mineral density (BMD) measurements are increasingly recognized as reliable predictors of fracture risk. Prospective data on fracture incidence in Asian men remain sparse. This prospective study aimed to determine the risk factors and the 10-year absolute fracture risk in Southern Chinese men. METHODS: This is a part of the Hong Kong Osteoporosis Study. One thousand eight hundred ten (1,810) community-dwelling, treatment-naive men aged 50 years or above were evaluated. Baseline demographic characteristics, clinical risk factors and BMD were recorded. Ten-year risk of osteoporotic fracture was calculated using Cox proportional hazards models. RESULTS: The mean age of subjects was 68.0 ± 10.3 years. After a mean follow-up period of 3.5±2.9 years (range 1 to 14 years), 37 incident low-trauma fractures were recorded. The incidence for all osteoporotic fractures and hip fractures was 635/100,000 and 123/100,000 person-years, respectively. The most significant predictors of osteoporotic fracture were history of fall (RR 14.5), femoral neck BMD T-score < -2.5 (RR 13.8) and history of fracture (RR 4.4). Each SD reduction in BMD was associated with a 1.8 to 2.6-fold increase in fracture risk. Subjects with seven clinical risk factors and BMD T-score of -1 had an absolute 10-year risk of osteoporotic fracture of 8.9%, but this increased to 22.7% if they also had a femoral neck BMD T-score of -2.5. CONCLUSIONS: These findings show substantial population differences in fracture incidence and risk prediction. The addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men.

Clinical risk factor assessment had better discriminative ability than bone mineral density in identifying subjects with vertebral fracture.

UNLABELLED: This study evaluated the characteristics of patients with vertebral fractures and examined the discriminative ability of clinical risk factors. The findings provide further insights into possible development of a simple, cost-effective scheme for fracture risk assessment using clinical risk factors to identify high-risk patients for further evaluation. INTRODUCTION: Vertebral fractures are the most common complication of osteoporosis. The aim of this study was to evaluate the characteristics of patients with vertebral fractures and to determine the discriminative ability of bone mineral density (BMD) and other clinical risk factors. METHODS: Postmenopausal Southern Chinese women (2,178) enrolled in the Hong Kong Osteoporosis Study since 1995 were prospectively followed up for fracture outcome. Subjects (1,372) with lateral spine radiographs were included in this study. Baseline demographic, BMD, and clinical risk factor information were obtained from a structured questionnaire. RESULTS: Subjects (299; 22%) had prevalent vertebral fractures. The prevalence of vertebral fractures increased with increasing age, number of clinical risk factors, and decreasing BMD. The odds of having a prevalent vertebral fracture per SD reduction in BMD after adjustment for age in Hong Kong Southern Chinese postmenopausal women was 1.5 for the lumbar spine and femoral neck. Analysis of the receiver operating characteristic curve revealed that bone mineral apparent density did not enhance fracture risk prediction. Subjects with ≥ 4 clinical risk factors had 2.3-fold higher odds of having a prevalent vertebral fracture while subjects with ≥ 4 clinical risk factors plus a low BMD (i.e., femoral neck T-score < -2.5) had 2.6-fold. Addition of BMD to clinical risk factors did not enhance the discriminative ability to identify subjects with vertebral fracture. CONCLUSIONS: Based on these findings, we recommend that screening efforts should focus on older postmenopausal women with multiple risk factors to identify women who are likely to have a prevalent vertebral fracture.

Elevated plasma adiponectin levels in patients with chronic obstructive pulmonary disease.

BACKGROUND: Adiponectin is an anti-inflammatory adipokine that may play a role in chronic obstructive pulmonary disease (COPD) pathogenesis. OBJECTIVE: To investigate the relationship between adiponectin, interleukin (IL) 6, IL-8 and C-reactive protein (CRP) and COPD by evaluating these biomarkers in ever-smokers with or without the disease. METHOD: Plasma levels of adiponectin, IL-6, IL-8 and CRP were measured using commercially available kits in COPD patients (n = 71), healthy ever-smokers (n = 62) and non-smokers (n = 51). RESULTS: There were significant increases in plasma adiponectin, IL-6 and CRP in COPD patients (median [IQR] 4.39 microg/ml [2.68-6.98], 4.19 pg/ml [<2.40-6.40], 8.75 mg/l [4.26-40.63], respectively) compared to healthy ever-smokers (1.90 microg/ml [0.86-2.86], <2.40 pg/ml [<2.40-2.77], 3.71 mg/l [1.97-10.37 mg/l], respectively, P < 0.001) and non-smokers (1.76 microg/ml [1.34-2.52], <2.40 pg/ml [<2.40-2.78], 3.12 mg/l [2.11-5.71], respectively, P < 0.001). COPD patients had lower plasma IL-8 levels than healthy ever-smokers. Among ever-smokers with or without COPD, plasma adiponectin, IL-6 and CRP levels were inversely correlated with forced expiratory volume in 1 second (% predicted) after adjustment for age, body mass index, smoking status and pack-years. CONCLUSION: Our findings suggest that in COPD patients, adiponectin might be associated with COPD pathogenesis.

Pim-1 plays a pivotal role in hypoxia-induced chemoresistance.

Hypoxia changes the responses of cancer cells to many chemotherapy agents, resulting in chemoresistance. The underlying molecular mechanism of hypoxia-induced drug resistance remains unclear. Pim-1 is a survival kinase, which phosphorylates Bad at serine 112 to antagonize drug-induced apoptosis. Here we show that hypoxia increases Pim-1 in a hypoxia-inducible factor-1alpha-independent manner. Inhibition of Pim-1 function by dominant-negative Pim-1 dramatically restores the drug sensitivity to apoptosis induced by chemotherapy under hypoxic conditions in both in vitro and in vivo tumor models. Introduction of siRNAs for Pim-1 also resensitizes cancer cells to chemotherapy drugs under hypoxic conditions, whereas forced overexpression of Pim-1 endows solid tumor cells with resistance to cisplatin, even under normoxia. Dominant-negative Pim-1 prevents a decrease in mitochondrial transmembrane potential in solid tumor cells, which is normally induced by cisplatin (CDDP), followed by the reduced activity of Caspase-3 and Caspase-9, indicating that Pim-1 participates in hypoxia-induced drug resistance through the stabilization of mitochondrial transmembrane potential. Our results demonstrate that Pim-1 is a pivotal regulator involved in hypoxia-induced chemoresistance. Targeting Pim-1 may improve the chemotherapeutic strategy for solid tumors.

Biological basis for soft tissue management in implant dentistry.

Good aesthetic finish of implant/restorations requires healthy peri-implant soft tissue at the appropriate location. The relevance of the peri-implant soft tissue seal, the biological width, the keratinized gingival zone and the need for effective plaque control in order to maintain peri-implant soft tissue health were discussed. The presence of a soft tissue seal/cuff around dental implants and abutments and its role in defense against infection were convincingly demonstrated in animal studies. In order to achieve long-term stable peri-implant health, it is important to achieve an adequate soft tissue seal around dental implant/restorations. The constant dimension of a biological width (of the soft tissue) often dictates where the final gingival margin will be. It is therefore not surprising that the position and stability of the alveolar bone ridge surrounding dental implants ultimately determines where the gingival margin rests. For dental implant restorations in the aesthetic zone, this is a crucial variable for the clinician to understand and deliver. Available data so far suggest that with good oral hygiene, peri-implant soft tissue health can be maintained irrespective if a keratinized gingival tissue zone surrounding implant/restoration is present. In reality, good oral hygiene is very difficult to achieve around dental restorations without the protection of a band of keratinized gingival tissue. Studies on peri-implantitis and peri-implant mucositis further demonstrated the causal relationship between dental plaque accumulation and peri-implant inflammation. It is therefore imperative that long-term maintenance care of dental implants and implant supported dental restorations should include a strict regime of plaque control and monitoring.

Developmental expression patterns and localization of DNA-binding protein inhibitor (Id3) in the mouse retina.

Id3 (inhibitor of DNA binding/differentiation), a member of the Id helix-loop-helix protein family, has long been studied as a positive regulator of proliferation and a negative regulator of differentiation. In this study, we examined the expression pattern and cellular phenotypes of Id3 in postnatal and adult mouse retina. Id3 was mainly expressed in the early postnatal inner retina. From the late postnatal development towards adulthood, Id3 expression was confined to the ganglion cell layer and the inner nuclear layer. Colocalization analysis showed that Id3 positive cells were identified as retinal ganglion cells and amacrine cells. The differential expression profiles of Id3 provide the groundwork for the elucidation of its possible role in retinal development.

Enhancement of manumycin A-induced apoptosis by methoxyamine in myeloid leukemia cells.

Farnesyltransferase inhibitors (FTIs) are currently under investigation for leukemia treatment. We evaluated the FTI manumycin A (manumycin) in two myeloid leukemia cell lines (U937 and HL-60). Manumycin induced nitric oxide production and apoptosis of the leukemia cells. Nitric oxide or other reactive oxygen species may induce oxidative DNA damage, and the number of apurinic sites increased after manumycin treatment, which was reversed by concurrent treatment with N-acetyl-L-cysteine. Since repair of DNA damage is important to cell survival, we hypothesized that methoxyamine, an inhibitor of base-excision repair, would enhance the antineoplastic effect of manumycin. The combination of manumycin and methoxyamine resulted in enhanced apoptosis by six criteria increased annexin V binding, release of mitochondrial cytochrome c into the cytosol, activation of caspase-9, activation of caspase-3, specific cleavage of poly-adenosyl ribose polymerase, and increase in the sub-G1 cell cycle fraction. The drug combination enhanced inhibition on the soft agar clonogenic assay and on the formazan dye cell viability assay. The effects of manumycin or manumycin plus methoxyamine on apoptosis were blocked by N-acetyl-L-cysteine, and partially by nitric oxide synthase inhibitors or scavenger of peroxide. We conclude that methoxyamine enhances manumycin-induced apoptosis in myeloid leukemia cells.

Cytochrome c release is upstream to activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells induced by manumycin and paclitaxel.

We previously demonstrated that the combination of a farnesyltransferase inhibitor, manumycin A, and paclitaxel had a synergistic antineoplastic effect on anaplastic thyroid cancer. In this study we investigated the apoptosis pathway involved. In ARO and KAT-4 cells, manumycin- plus paclitaxel-induced DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8, and caspase-3. The drug combination enhanced the activation of caspase-9, caspase-8, and caspase-3 and cytochrome c release into the cytosol. Cytochrome c release was not affected by the inhibitors of caspase-9, caspase-8 and caspase-3. In a cell-free reconstitution assay, DNA fragmentation occurred after incubating nuclei purified from untreated KAT-4 cells with deoxy-ATP, exogenous cytochrome c and S-100 extracts from control KAT-4 cells, and also after incubation of purified KAT-4 nuclei with S-100 extracts from KAT-4 cells treated with manumycin-plus-paclitaxel. In both cases, the DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8 and caspase-3. We concluded that the cytochrome c release was upstream of the activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells treated with manumycin plus paclitaxel, and that the interaction between manumycin and paclitaxel occurred at or upstream of cytochrome c in the apoptosis regulatory pathway in anaplastic thyroid cancer cells.

Potential new antitumor agents from an innovative combination of demethylcantharidin, a modified traditional Chinese medicine, with a platinum moiety.

A combination of demethylcantharidin, a modified component of a traditional Chinese medicine (TCM), with a platinum moiety has produced a series of TCM-based platinum compounds [Pt(C(8)H(8)O(5))(NH(2)R)(2)] 1-5, which demonstrate selective cytotoxicity toward SK-Hep-1 (human liver) cell line, and circumvention of cross-resistance. The inclusion of demethylcantharidin rendered the compounds highly active as protein phosphatase (PP2A) inhibitors. The new TCM-Pt compounds may possess a novel dual mechanism of antitumor action: inhibition of PP2A and platination of DNA.

Angiogenesis inhibition in the in vivo antineoplastic effect of manumycin and paclitaxel against anaplastic thyroid carcinoma.

Our laboratory has investigated the anticancer effects of combined manumycin (a farnesyltransferase inhibitor) and paclitaxel (a microtubule inhibitor) against anaplastic thyroid carcinoma (ATC). In this study we reported the in vivo efficacy of this combination against ATC cells and the lack of toxicity of this treatment in mice. We observed that manumycin-treated tumors looked paler than both control and paclitaxel-treated tumors. We hypothesized that angiogenesis inhibition mediated part of the in vivo effect of manumycin. This hypothesis was supported by the findings that manumycin significantly inhibited angiogenesis (as directly demonstrated by measurement of hemoglobin content and vascular area) in Matrigel implanted into mice, that manumycin decreased the vascular endothelial growth factor in hypoxic ATC cells, and that both manumycin and paclitaxel inhibited endothelial cell proliferation. Interestingly, inhibition of endothelial tubule formation in Matrigel was enhanced by combining manumycin and paclitaxel. As angiogenesis and tumor growth are continuous processes, we investigated the effect of sustained delivery of manumycin and found that paclitaxel plus slow release manumycin (13.25 mg/kg x week) inhibited ATC xenografts more than paclitaxel plus intermittent manumycin (15 mg/kg x week). In conclusion, manumycin plus paclitaxel is an effective combination against ATC, and inhibition of angiogenesis plays a role in the antineoplastic effect of this combination.

NTDB: Thermodynamic Database for Nucleic Acids.

A new thermodynamic database for normal and modified nucleic acids has been developed. This Thermodynamic Database for Nucleic Acids (NTDB) includes sequence, structure and thermodynamic information as well as experimental methods and conditions. In this release, there are 1851 sequences containing both normal and modified nucleic acids. A user-friendly web-based interface has been developed to allow data searching under different conditions. Useful thermodynamic tools for the study of nucleic acids have been collected and linked for easy usage. NTDB is available at http://ntdb.chem.cuhk.edu.hk.

Phenytoin and enteral feedings: does evidence support an interaction?

OBJECTIVE: To systematically review the reported interaction between oral dosage forms of phenytoin and enteral feeding formulations with respect to the evidence supporting or refuting its existence, proposed mechanism(s) underlying the interaction, and recommended interventions. DATA SOURCES: We conducted a MEDLINE search (1966-April 2000) for English-language articles on phenytoin-enteral feeding interactions; the search terms used were phenytoin, enteral feeding, and/or interaction, and/or in vitro. This search was supplemented by a bibliographic review of all relevant articles. STUDY SELECTION: Prospective, randomized, controlled studies; prospective, nonrandomized, controlled studies; prospective, nonrandomized, uncontrolled studies; retrospective studies; clinical experience reports; case reports; in vitro studies; and letters were evaluated for relevant information. DATA EXTRACTION: Data elements abstracted from these articles were study design, type (patients or healthy volunteers) and number of subjects involved, method of administration of phenytoin and enteral feeding, formulation of phenytoin, type of feeding (and whether it was continuous or interrupted), major findings, and proposed mechanisms of the interaction. DATA SYNTHESIS: Although four prospective, randomized, controlled trials in healthy human volunteers refute the existence of the interaction, there are numerous reports and studies showing dramatic decreases of serum phenytoin concentrations in patients when it is coadministered with enteral feeding formulations. Therefore, evidence supports the existence of this interaction in patients and in vitro studies, but not in healthy volunteers. Unfortunately, the exact mechanisms underlying this interaction remain unknown. Many methods have been devised to prevent and treat the interaction once it has occurred; however, a single, generally accepted, and practical intervention strategy is still lacking. CONCLUSIONS: The exact role of enteral feeding in this interaction is unclear due to the lack of prospective, randomized, controlled trials performed in patients. However, decreased serum phenytoin concentrations associated with enteral feeding may increase the risk of seizures. Clinicians should be aware of this potential drug-nutrient interaction and design a patient-specific care plan that includes consideration of the enteral feeding formulation and method of administration, as well as the phenytoin dosage form, schedule of administration, and monitoring.

Manumycin enhances the cytotoxic effect of paclitaxel on anaplastic thyroid carcinoma cells.

Despite the current multimodal approach to treatment of anaplastic thyroid cancer (ATC), the prognosis for patients with the disease is poor. New effective therapy for ATC is desperately needed. Thus, we investigated the effects of manumycin (a farnesyl:protein transferase inhibitor), alone and in combination with other drugs frequently used to treat ATC, in six human ATC cell lines: ARO, C643, DRO, Hth-74, KAT-4, and KAT-18. By means of a formazan dye-based spectrophotometric assay of cell viability and light microscopy, manumycin was shown to decrease the number of viable cells in all six of the cell lines though to a lesser degree in DRO and C643 cells than in ARO, Hth-74, KAT-4, and KAT-18 cells. In combination, manumycin enhanced the effect of paclitaxel in all six of the cell lines. The mechanism of cell death was investigated by measuring caspase-3 activity, immunoblotting with anti-poly-(ADP-ribose)polymerase (PARP) antibody and electrophoresis of DNA. After an 18-h incubation, manumycin plus paclitaxel caused enhanced activation of caspase-3 activity, cleavage of PARP into Mr 89,000 and 28,000 fragments, and internucleosomal fragmentation of DNA (all of which are characteristic of apoptotic cell death). In contrast, neither manumycin alone, paclitaxel alone, doxorubicin alone, nor doxorubicin plus manumycin produced significant specific cleavage of PARP and internucleosomal DNA fragmentation after 18 h of incubation. The in vivo effect and toxicity of combined manumycin and paclitaxel treatments were evaluated in a nude mouse xenograft model using ARO and KAT-4 cells. Drugs were injected i.p. on days 1 and 3 of a 7-day cycle for three cycles. Both manumycin (7.5 mg/kg/dose) and paclitaxel (20 mg/kg/dose) had significant inhibitory effects on tumor growth. Combined manumycin and paclitaxel treatments seemed as effective as manumycin against ARO cells and more effective than either manumycin or paclitaxel alone against KAT-4 cells. No significant morbidity or mortality was caused by the treatments. In conclusion, manumycin can inhibit the growth of ATC both in vitro and in vivo. Manumycin plus paclitaxel has enhanced cytotoxic effects and increased apoptotic cell death in ATC cells in vitro compared with either drug by itself. The combination of manumycin and paclitaxel is also effective in vivo with no significant toxicity observed. The lack of synergy observed in this in vivo experiment may be due to a ceiling effect, and further experimentation is warranted to ascertain the optimal way to combine these two agents for maximal therapeutic effects.