An apoptosis-independent role of SMAC in tumor suppression

Reduced expression of the pro-apoptotic protein SMAC (second mitochondria-derived activator of caspase) has been reported to correlate with cancer progression, while its significance and underlying mechanisms are poorly understood. In this study, we investigated the role of SMAC in intestinal tumorigenesis using both human samples and animal models. Decreased SMAC expression was found to correlate with increased cIAP2 expression and higher grades of human colon cancer. In mice, SMAC deficiency significantly increased the incidence and size of colon tumors induced by azoxymethane (AOM)/dextran sulfate sodium salt (DSS), and highly enriched β-catenin hot spot mutations. SMAC deficiency also significantly increased the incidence of spontaneous intestinal polyps in APC(Min/+) mice. Loss of SMAC in mice led to elevated levels of cIAP1 and cIAP2, increased proliferation and activation of the NF-κB p65 subunit in normal and tumor tissues. Unexpectedly, SMAC deficiency had little effect on the incidence of precursor lesions, or apoptosis induced by AOM or DSS, or in established tumors in mice. Furthermore, SMAC knockout enhanced TNFα-mediated NF-κB activation via cIAP2 in HCT 116 colon cancer cells. These results demonstrate an essential and apoptosis-independent function of SMAC in tumor suppression and provide new insights into the biology and targeting of colon cancer.

Secretory TAT-peptide-mediated protein transduction of LIF receptor α-chain distal cytoplasmic motifs into human myeloid HL-60 cells

The distal cytoplasmic motifs of leukemia inhibitory factor receptor α-chain (LIFRα-CT3) can independently induce intracellular myeloid differentiation in acute myeloid leukemia (AML) cells by gene transfection; however, there are significant limitations in the potential clinical use of these motifs due to liposome-derived genetic modifications. To produce a potentially therapeutic LIFRα-CT3 with cell-permeable activity, we constructed a eukaryotic expression pcDNA3.0-TAT-CT3-cMyc plasmid with a signal peptide (ss) inserted into the N-terminal that codes for an ss-TAT-CT3-cMyc fusion protein. The stable transfection of Chinese hamster ovary (CHO) cells via this vector and subsequent selection by Geneticin resulted in cell lines that express and secrete TAT-CT3-cMyc. The spent medium of pcDNA3.0-TAT-CT3-cMyc-transfected CHO cells could be purified using a cMyc-epitope-tag agarose affinity chromatography column and could be detected via SDS-PAGE, with antibodies against cMyc-tag. The direct administration of TAT-CT3-cMyc to HL-60 cell culture media caused the enrichment of CT3-cMyc in the cytoplasm and nucleus within 30 min and led to a significant reduction of viable cells (P < 0.05) 8 h after exposure. The advantages of using this mammalian expression system include the ease of generating TAT fusion proteins that are adequately transcripted and the potential for a sustained production of such proteins in vitro for future AML therapy.

Biomimetic compound eye with a high numerical aperture and anti-reflective nanostructures on curved surfaces

Biomimetic compound eyes with a high numerical aperture on a curved surface were successfully fabricated by intelligent integration of traditional top-down and bottom-up micro- and nanofabrication methods together. In addition, the new hybrid micro- and nanofabrication method allows us to fabricate the antireflective nanostructures on each ommatidium to increase its vision sensitivity by improving the light transmission. The fabricated compound eye was optically characterized and was shown to have a numerical aperture of 0.77 for each ommatidium. Furthermore, it is shown that the transmission of the compound eye can be improved by 2.3% for the wavelength of 632.8 nm and a clearer image can be formed by the fabricated compound eye with antireflective nanostructures compared with that without antireflective nanostructures. In addition, the developed hybrid manufacturing method can be adapted to the fabrication of other complex micro- and nanodevices for photonics or other research areas.

Pre-transplant myeloid dendritic cell deficiency associated with cytomegalovirus infection and death after kidney transplantation

BACKGROUND

Dendritic cells (DCs) are potent antigen-presenting cells critical for immunity. We previously demonstrated a significant association between pre-transplant blood myeloid dendritic cell (mDC) and plasmacytoid dendritic cell (pDC) deficiency and post-transplant BK viremia in renal transplant recipients. In the current post-hoc analysis, we studied the association of these same pre-transplant DC levels with other post-transplant outcomes.

METHODS

Pre-transplant peripheral blood mDC and pDC levels were quantified using flow cytometry in 78 patients undergoing kidney transplantation. Post-transplant outcomes were analyzed, including infection, rejection, and patient death, with a median follow-up of 5.3 years. Associations between DC levels and outcomes were assessed using logistic regression analysis and Cox proportional hazards models.

RESULTS

An independent association of mDC levels with post-transplant cytomegalovirus infection (adjusted odds ratio 7.0, P = 0.01) and patient death (adjusted hazard ratio 13.0, P = 0.015) was found. No associations were demonstrated between levels of either DC subtype and bacterial infections or rejection.

CONCLUSIONS

Pre-transplant mDC deficiency is significantly associated with CMV infection and death after kidney transplantation.

Meta-analysis: the use of carbon dioxide insufflation vs. room air insufflation for gastrointestinal endoscopy

BACKGROUND

Carbon dioxide (CO(2)) insufflation has been proposed as an alternative to air insufflation to distend the lumen in gastrointestinal (GI) endoscopy.

AIM

To perform a systematic review with meta-analysis of randomised controlled trials (RCTs) in which CO(2) insufflation was compared with room air insufflation in GI endoscopy.

METHODS

Electronic and manual searches were combined to search RCTs. After methodological quality assessment and data extraction, the efficacy and safety of CO(2) insufflation were systematically assessed.

RESULTS

Twenty-one RCTs [13 on colonoscopy, four on endoscopic retrograde cholangiopancreatography (ERCP), two on double-balloon enteroscopy (DBE), one on oesophagogastroduodenoscopy, and one on flexible sigmoidoscopy] were identified. For colonoscopy, CO(2) insufflation resulted lower postprocedural pain intensity, and increased the proportion of patient without pain at 1 h (RR: 1.84, 95% CI: 1.37-2.47) and 6 h (RR: 1.28; 95% CI: 1.14-1.44) postprocedure. For ERCP, the pain-releasing effect of CO(2) insufflation was not obvious (SMD: -1.48, 95% CI: -3.56, 0.59). CO(2) insufflation revealed no consistent advantages in the RCTs of DBE, but was shown as safe as air insufflation in oesophagus/stomach endoscopic submucosal dissection in one study. pCO(2) level showed no significant variation during these procedures.

CONCLUSIONS

Compared with air insufflation, CO(2) insufflation during colonoscopy causes lower postprocedural pain and bowel distension without significant pCO(2) variation. More RCTs are needed to assess its advantages in other GI endoscopic procedures.

Bidirectional association between depression and obesity in middle-aged and older women

OBJECTIVE

Although it has been hypothesized that the depression-obesity relation is bidirectional, few studies have addressed this hypothesis in a prospective setting. We aimed to examine the bidirectional relationship in middle-aged and elderly women.

SUBJECTS

A total of 65 955 women aged 54-79 years in the Nurses' Health Study were prospectively followed from 1996 to 2006 with updated information on body weight, depression status and various covariates every 2 years. Depression was defined as self-report of physician-diagnosed depression and/or antidepressant use. Obesity was defined as a BMI ≥30.0 kg m(-2). The first three waves (1996-2000) were used as the baseline period and the last three waves (2002-2006) were used as the follow-up period.

RESULTS

After adjusting for baseline age, physical activity, comorbidities, BMI and other covariates, depression at the baseline period was associated with an increased risk of obesity at the follow-up period in all women (multivariate-adjusted odds ratio (OR), 1.38; 95% confidence interval (95% CI), 1.24-1.53) and baseline non-obese women (OR, 1.51; 95% CI, 1.36-1.67). In the opposite direction, after adjusting for baseline age, physical activity, comorbidities, depression status and other covariates, obese women at baseline had a moderately increased risk of depression at the follow-up period compared with normal-weight women (OR, 1.11; 95% CI, 1.03-1.18), and this association was similar for new onset of depression (OR for obese versus normal weight women, 1.10; 95% CI, 1.02-1.20).

CONCLUSIONS

Our results suggest a bidirectional association between depression and obesity in middle-aged and elderly women. Future studies are needed to confirm our findings in different populations, and investigate the potential mechanisms underlying this association. Our results underscore the importance of early detection and proper behavioral modifications to lower the burden of both conditions.

Use of antidepressant medication and risk of type 2 diabetes: results from three cohorts of US adults

AIMS/HYPOTHESIS

The results of several studies have suggested a potential positive association between use of antidepressant medication (ADM) and incident type 2 diabetes mellitus. We examined this association in three cohorts of US adults.

METHODS

We followed 29,776 men in the Health Professionals Follow-up Study (HPFS, 1990-2006), 61,791 women in the Nurses' Health Study I (NHS I, 1996-2008) and 76,868 women in NHS II (1993-2005), who were free of diabetes mellitus, cardiovascular disease or cancer at baseline. The mean baseline ages for participants from the HPFS and NHS I and II were 56.4, 61.3 and 38.1 years, respectively. ADM use and other covariates were assessed at baseline and updated every 2 years. A time-dependent Cox proportional hazards model was used, and HRs were pooled together across the three cohorts.

RESULTS

During 1,644,679 person-years of follow-up, we documented 6,641 new cases of type 2 diabetes. ADM use was associated with an increased risk of diabetes in all three cohorts in age-adjusted models (pooled HR 1.68 [95% CI 1.27, 2.23]). The association was attenuated after adjustment for diabetes risk factors and histories of high cholesterol and hypertension (1.30 [1.14, 1.49]), and further attenuated by controlling for updated BMI (1.17 [1.09, 1.25]). Use of selective serotonin reuptake inhibitors and other antidepressants (mainly tricyclic antidepressants) were both associated with an elevated risk of diabetes, with pooled multivariate-adjusted HRs of 1.10 (1.00, 1.22) and 1.26 (1.11, 1.42), respectively.

CONCLUSIONS/INTERPRETATION

The results suggest that ADM users had a moderately elevated risk of type 2 diabetes mellitus compared with non-users, even after adjustment for BMI.

Peak BMD assessment in a Chinese infantry recruit group

Peak bone mass is an important factor influencing the occurrence of osteoporosis and osteoporotic fracture in adulthood. We measured the areal bone mineral density (BMD) in a Chinese male infantry recruit group ranging in age from 17 to 23 years and subsequently assessed peak BMD at the lumbar vertebrae and hip. This study included 812 Chinese men of Han ethnicity from 11 provinces and municipalities of China. The BMD, bone mineral content and the bone area of the lumbar vertebrae (L1-4), left femoral neck and total hip were measured using dual-energy X-ray absorptiometry. Height, weight, waist and hip circumference were also measured at the same time. BMD at the lumbar vertebrae, femoral neck and total hip reached a plateau at 22 years of age. The peak value of BMD at these 3 sites was 1.209±0.175, 1.098±0.177 and 1.122±0.151 (g/cm2), respectively. Stepwise regression analysis showed that age and weight most contributed to the variance in BMD (P<0.001). The average age when reaching peak BMD in this study is earlier than the ages reported in previous studies, and the value of peak BMD is higher than that reported previously in Chinese males. This study provides the newest peak BMD data on Chinese men.

MicroRNAs of rat articular cartilage at different developmental stages identified by Solexa sequencing

BACKGROUND

Expression profiles of microRNAs (miRNAs) can shape the repertoire of proteins expressed in development, differentiation and diseases. This study aimed to identify miRNA profile of articular cartilage at different developmental stages in rats.

METHODS

Three small RNA libraries were constructed from the femoral head cartilage of Sprague-Dawley (SD) rats at postnatal day 0, day 21 and day 42 and sequenced by a deep sequencing approach. Then a bioinformatics approach was employed to distinguish genuine miRNAs from small RNAs represented in the mass sequencing data. The expression of indicated miRNAs was determined by stem-loop RT-qPCR to valuate the consistency with Solexa sequencing.

RESULTS

Two hundred and fifty-eight of 310 known miRNA and miRNA* genes were organized into 91 compact clusters. Two hundred and forty-six miRNAs were detected in all three small RNA libraries of rat articular cartilage. Forty-six, fifty-two and fifty-six miRNA* genes were identified from three small RNA libraries, respectively, and 86 novel miRNA candidate genes were found simultaneously. In addition, 23 known miRNAs were up-regulated (fold change ≥ 4); six were down-regulated (fold change ≤ -4) during articular cartilage development. The predicted targets of differentially expressed miRNAs were locally secreted factors and transcription factors that regulate proliferation and differentiation of chondrocytes. The same expression tendency of indicated miRNAs during articular cartilage development stages was observed by using Solexa sequencing and stem-loop RT-qPCR.

CONCLUSION

Our study provided a unique opportunity to decipher how the elaboration of the miRNA repertoire contributes to the development process of articular cartilage.

Surface alloy formation of noble adatoms adsorbed on Si(111)-√3 × √3-Pb surface: a first-principles study

The geometric structures, stability and electronic properties of initial stages of surface alloy formation for noble atoms adsorbed on Si(111)-)-√3 × √3-Pb surfaces have been comparatively and extensively studied by using first-principles calculations within density functional theory. Our results revealed that an Au trimer rather than a tetramer adsorption induces a surface alloy by combining with Pb atoms in covalent bonds, exhibiting semiconducting characteristics due to the localization of surface states. The stability of the two-dimensional (2D) surface alloy obeys the Hume-Rothery rule. The electronic structures of the 2D surface alloy are sensitive to the number of Au adatoms and can be modulated by the quantity of Au adatoms. Unlike the Au atoms, our further calculations indicated that adsorption of Ag or Cu atoms on the surface cannot form a surface alloy with Pb atoms in the surface layer due to a weaker interaction or smaller radius.

Exploration of acridine scaffold as a potentially interesting scaffold for discovering novel multi-target VEGFR-2 and Src kinase inhibitors

VEGFR-2 and Src kinases both play important roles in cancers. In certain cancers, Src works synergistically with VEGFR-2 to promote its activation. Development of multi-target drugs against VEGFR-2 and Src is of therapeutic advantage against these cancers. By using molecular docking and SVM virtual screening methods and based on subsequent synthesis and bioassay studies, we identified 9-aminoacridine derivatives with an acridine scaffold as potentially interesting novel dual VEGFR-2 and Src inhibitors. The acridine scaffold has been historically used for deriving topoisomerase inhibitors, but has not been found in existing VEGFR-2 inhibitors and Src inhibitors. A series of 21 acridine derivatives were synthesized and evaluated for their antiproliferative activities against K562, HepG-2, and MCF-7 cells. Some of these compounds showed better activities against K562 cells in vitro than imatinib. The structure-activity relationships (SAR) of these compounds were analyzed. One of the compounds (7r) showed low μM activity against K562 and HepG-2 cancer cell-lines, and inhibited VEGFR-2 and Src at inhibition rates of 44% and 8% at 50μM, respectively, without inhibition of topoisomerase. Moreover, 10μM compound 7r could reduce the levels of activated ERK1/2 in a time dependant manner, a downstream effector of both VEGFR-2 and Src. Our study suggested that acridine scaffold is a potentially interesting scaffold for developing novel multi-target kinase inhibitors such as VEGFR-2 and Src dual inhibitors.

Higher adiponectin levels predict greater weight gain in healthy women in the Nurses' Health Study

Adiponectin and resistin's possible roles in weight regulation have received little attention. We tested the hypothesis that adipokine levels predict future weight gain in women in the Nurses' Health Study. Among women who provided blood samples in 1990, we studied 1,063 women who did not develop diabetes ("healthy") and 984 women who subsequently developed diabetes. Total and high-molecular-weight (HMW) adiponectin and resistin levels were measured using enzyme-linked immunosorbent assay. Women who did not developed diabetes had a mean BMI of 26.3 ± 6.0 kg/m(2) at baseline and gained 2.0 ± 6.1 kg over 4 years. Women who developed diabetes had a mean BMI of 30.1 ± 5.4 kg/m(2) at baseline, and gained 2.4 ± 7.1 kg over 4 years. In women who did not developed diabetes, higher baseline levels of total and HMW adiponectin were associated with significantly greater weight gain after adjustment for age, BMI, physical activity, diet, and other covariates: women in the highest quintile of total adiponectin gained 3.18 kg compared to women in the lowest quintile who gained 0.80 kg (fully adjusted; P for trend <0.0001). Adiponectin was not significantly associated with weight gain in women who subsequently developed diabetes. Resistin levels were not associated with weight gain in either women who did or did not develop diabetes during the follow-up. We conclude that elevated adiponectin levels are associated with higher weight gain in healthy women, independent of confounding risk factors. High adiponectin production by adipocytes might be a sign of "healthy" adipose tissue with further capacity to store fat.