Frequency of PIK 3CA Mutations in Chinese HER2+ Metastatic Breast Cancer Patients and Association with Clinical Benefit to Lapatinib and Capecitabine Treatment

Background: Activating mutations in PIK3CA are frequent in breast cancer (Campbell et al. Cancer Res 2004;64:7678-7681). Previous analyses suggest that the presence of PIK3CA activating mutations were associated with poor clinical outcome (Li et al. Breast Can Res Treat 2006;96:91-95) and could confer resistance to treatment with trastuzumab (T) (Berns et al. Cancer Cell 2007;12:395-402). Lapatinib (L) is an oral tyrosine kinase inhibitor targeting EGFR and HER2 pathways. L plus capecitabine (C) has demonstrated efficacy in women with HER2+ metastatic breast cancer (MBC) previously treated with T (Geyer et al. N Engl J Med 2006;355(26):2733-2743). EGF109491 evaluated the efficacy of L+C in 52 Chinese HER2+ MBC patients. The clinical benefit rate (CBR) was 57.7% (PR 44% and SD 44%) and median progression free survival (PFS) was 6.3 months. The purpose of this analysis was to establish the frequency of PIK3CA mutations in this small cohort of Chinese patients and to determine if the presence of a PIK3CA mutation has any impact on clinical benefit to L+C.Methods: 38/52 patients provided tumor samples for biomarker analysis. Briefly, DNA was extracted from these tumor samples, amplified by PCR and sequenced by Pyrosequencing methods to identify the presence of frequent activating mutations in exons 9 and 20 in PIK3CA. Mutation status was tested for association with CBR and PFS using contingency table analysis and proportional hazards analysis respectively.Results:11/38 (29%) patients harbored a mutation in the PIK3CA gene, consistent with published frequencies. 9/11 mutations reside in the catalytic domain and 2/11 mutations reside in the accessory domain of the gene. There was no statistical association with CBR (p=0.639) or PFS (HR=1.01, p=0.989) in PIK3CA wildtype patients vs. PIK3CA mutant patients. PIK3CA wildtype n=27 (%)PIK3CA Mutation n=11 (%)CR0 (0)0 (0)PR12 (44%)4 (36%)SD13 (48%)5 (45%)PD1 (4%)1 (9%)Unknown1 (4%)1 (9%)HR1.01 (p=0.989) Conclusion: The frequency of PIK3CA mutations in this small cohort of Chinese HER2+ MBC patients is consistent with published frequencies. There was no statistically significant association between the presence of a PIK3CA mutation and clinical benefit to L+C in these patients. These results are in agreement with previous reports that mutations in PIK3CA do not seem to impact clinical outcome following L-containing treatment regimens.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1140.

Reactive oxygen species in rostral ventrolateral medulla modulate cardiac sympathetic afferent reflex in rats

AIM

The aim of the present study was to investigate whether reactive oxygen species (ROS) in rostral ventrolateral medulla (RVLM) modulate cardiac sympathetic afferent reflex (CSAR) and the enhanced CSAR response caused by microinjection of angiotensin II (Ang II) into the paraventricular nucleus (PVN).

METHODS

Under urethane and alpha-chloralose anaesthesia, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in sinoaortic-denervated and cervical-vagotomized rats. The CSAR was evaluated by the RSNA response to epicardial application of capsaicin (1.0 nmol).

RESULTS

Bilateral RVLM microinjection of tempol (a superoxide anion scavenger) or polyethylene glycol-superoxide dismutase (PEG-SOD, an analogue of endogenous superoxide dismutase) attenuated the CSAR, but did not cause significant change in baseline RSNA and MAP. NAD(P)H oxidase inhibitors apocynin or phenylarsine oxide (PAO) also showed similar effects, but SOD inhibitor diethyldithio-carbamic acid (DETC) enhanced the CSAR and baseline RSNA, and increased the baseline MAP. Bilateral PVN microinjection of Ang II (0.3 nmol) enhanced the CSAR and increased RSNA and MAP, which was inhibited by the pre-treatment with RVLM administration of tempol, PEG-SOD, apocynin or PAO. The pre-treatment with DETC in the RVLM only showed a tendency in potentiating the CSAR response of Ang II in the PVN, but significantly potentiated the RSNA and MAP responses of Ang II.

CONCLUSION

These results suggest that the NAD(P)H oxidase-derived ROS in the RVLM modulate the CSAR. The ROS in the RVLM is necessary for the enhanced CSAR response caused by Ang II in the PVN.

Osterix enhances BMSC-associated osseointegration of implants

Cellular and molecular events in osseointegration at the dental implant surface remain largely unknown. We hypothesized that bone marrow stromal cells (BMSCs) participate in this process, and that osterix (Osx) promotes implant osseointegration. To prove this hypothesis, we tracked double-labeled BMSCs in implantation sites created in nude mice transplanted with these cells. We also inserted implants into the femurs of our established transgenic mice after local administration of viruses encoding Osx, to determine the osteogenic effects of Osx. Immunohistochemical results demonstrated that BMSCs can recruit from peripheral circulation and participate in wound healing and osseointegration after implantation. Microcomputed tomography (microCT) analysis revealed an increased bone density at the bone-to-implant interface in the Osx group, and histomorphometric analysis indicated an elevated level of bone-to-implant contact in the Osx group. We concluded that exogenous BMSCs participate in the osseointegration after implantation, and that Osx overexpression accelerates osseointegration.

Suppression of lung adenocarcinoma through menin and polycomb gene-mediated repression of growth factor pleiotrophin

Menin upregulates transcription of cell-cycle inhibitors to suppress endocrine tumors, but it is poorly understood how menin suppresses non-endocrine tumors such as lung cancer. Here, we show that menin inhibits proliferation of human lung cancer cells and growth of lung cancer in mice. The menin-mediated tumor suppression requires repression of growth factor pleiotrophin (PTN), which binds to its cell surface receptor, anaplastic lymphoma kinase (ALK) that is activated in certain lung adenocarcinomas. Menin represses PTN transcription and PTN-induced proliferation of human lung cancer cells, and menin expression is substantially reduced in primary human lung adenocarcinomas. Notably, menin binds the PTN locus and enhances Polycomb gene Enhancer of Zeste homolog 2 (EZH2)-mediated histone H3 lysine 27 trimethylation (H3K27m3), a negative mark for gene transcription but does not affect histone H3K4 methylation that is usually upregulated by menin in endocrine cells. Together, our findings indicate that menin suppresses lung cancer partly through increasing Polycomb gene-mediated H3K27 methylation and repressing PTN transcription, unraveling a novel, epigenetically regulated PTN-ALK signaling pathway in suppressing lung cancer.

Examination of the semen quality of patients with uraemia and renal transplant recipients in comparison with a control group

To examine the semen quality of patients with uraemia and renal transplant recipients, 40 patients with uraemia and 40 renal transplant recipients were included. According to their interval of post-transplantation, renal transplant recipients were subdivided into group A (22) < or =2 years and group B (18) >2 years. A total of 40 healthy men with normal fertility were included as the controls. Semen samples from all subjects were collected and analysed. The fertility index (FI) value was calculated. The FI value of the normal fertility men was 13.02 (14.26), that of the renal transplant recipient groups A and B were 5.53 (8.30) and 9.27 (22.49) respectively, while the FI of the patients with uraemia was 0.23 (0.76). Compared with the uraemia group, the FI values of renal transplant recipient group either group A or group B were significantly better (P < 0.01). However, compared with the normal control group, the FI values of renal transplant recipient group A were lower (P < 0.01), while there was no significant difference between group B and the control group (P > 0.05). In conclusion, the FI of renal transplant recipients was recovered close to the level of healthy men with normal fertility 2 years after transplantation.

Ultrastructural changes of nucleoli in common wheat induced by actinomycin DPeople's Republic of China

Common wheat root tip meristematic cells were treated with low concentrations of actinomycin D (ActD), then stained whole by silver nitrate. We showed by transmission electron microscopy that the typical nucleolar structure did not form, but a granular and fibrillar network was exhibited in the nucleolar region. Our results support a correlation between nucleolar organization/assembly and the activation of RNA Polymerase I transcription. Furthermore, we speculate that the fibrillar network present in the nucleolar region of ActD treated cells may represent the basic skeletal structure required to support the nucleolus.

Preparation and superconductivity of iron selenide thin films

FeSe(x) (x = 0.80,0.84,0.88,0.92) thin films were prepared on SrTiO(3)(001)(STO), (La,Sr)(Al,Ta)O(3)(001) (LSAT), and LaAlO(3)(001) (LAO) substrates by a pulsed laser deposition method. All of the thin films show single-phase and c-axis oriented epitaxial growth, and are superconducting. Among them, the FeSe(0.88) thin films show a T(c,onset) of 11.8 K and a T(c,0) of 3.4 K. The upper critical magnetic field is estimated to be 14.0 T.

Mixing and segregation of microspheres in microchannel flows of mono- and bidispersed suspensions

We investigate the mixing and segregation of mono- and bidispersed microsphere suspensions in microchannel flows. These flows are common in biological microelectromechanical systems (BioMEMS) applications handling blood or suspensions of DNA. Suspension transport in pressure driven flows is significantly hindered by shear-induced migration, where particles migrate away from the walls and are focused in the center due to multibody hydrodynamic interactions. The microchannels used in this study have geometries that induce chaotic advection in Newtonian fluids. Our results show that mixing in straight, herringbone and staggered herringbone channels depends strongly on volume fraction. Due to this complex interplay of advection and shear-induced migration, a staggered herringbone channel that typically results in chaotic mixing is not always effective for dispersing particles. The maximum degree of segregation is observed in a straight channel once the maximum packing fraction is reached at channel center. We modify a one-dimensional suspension balance model [R. Miller and J. Morris, J. Non-Newtonian Fluid Mech. 135, 149 (2006)] to describe the behavior at the center of the straight channel. The degree of mixing is then calculated as a function of bulk volume fraction, predicting the volume fraction that results in the maximum degree of segregation. In bidispersed suspension flow, it is shown that mixing of the larger species is enhanced in straight and staggered herringbone channels while segregation is enhanced at moderate volume fractions in herringbone channels. This suggests mixing and separations can be tailored by adjusting both the suspension properties and the channel geometry.

Effects of anti-hypertensive drugs on production of soluble fms-like tyrosine kinase 1 and soluble endoglin from human normal and pre-eclamptic placentas in vitro

1. Increases in soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) contribute to the pathogenesis of pre-eclampsia. Soluble Flt-1 binds to circulating free vascular endothelial growth factor and placenta growth factor and this is associated with endothelial dysfunction. Soluble endoglin, a transforming growth factor (TGF)-beta coreceptor, was reported to synergize with sFlt-1 to amplify endothelial dysfunction by inhibiting TGF-beta1-mediated vasorelaxation. 2. The aim of the present study was to examine whether the antihypertensive drugs clonidine (0.08-1.3 microg/mL), diazoxide (25-300 microg/mL), frusemide (60-1000 microg/mL) and hydralazine (6.3-100 microg/mL) have any effect on placental production of sFlt-1 and sEng in placentas from normal and pre-eclamptic pregnancies. 3. Explants were taken from non-laboured term placentas of normal pregnancy (n = 5) and women with pre-eclampsia (n = 5). Villous explants were cultured with increasing doses of antihypertensive drugs. Placental sFlt-1 and sEng production was examined using ELISA. 4. Baseline sFlt-1 production was higher in placentas from women with pre-eclampsia than from normal pregnancy (4.5 +/- 1.4 vs 3.2 +/- 0.6 ng/mg of total protein, respectively; P < 0.001), as was sEng production (9.0 +/- 2.3 vs 4.1 +/- 0.6 ng/mg of total protein, respectively; P < 0.001). With the exception of frusemide, none of the antihypertensive drugs tested had any effect on sFlt-1 and sEng production from placental explants of normal pregnancy and women with pre-eclampsia. Increasing frusemide concentrations were correlated with increased sEng production in normal pregnancy (P < 0.005). 5. In conclusion, placental sFlt-1 and sEng production was higher in pre-eclampsia and antihypertensive drugs had no effect on placental production of sFlt-1 and sEng in vitro.

Development of enzyme-linked immunosorbent assay (ELISA) for the detection of neomycin residues in pig muscle, chicken muscle, egg, fish, milk and kidney

A colorimetric competitive direct enzyme-linked immunosorbent assay (ELISA) method was developed using polyclonal antibody to determine neomycin residues in food of animal origin. No cross-reactivity of the antibody was observed with other aminoglycosides. The limit of detection of the method was 0.1μg/kg. A simple and efficient sample extraction method was established with recoveries of neomycin ranged from 75% to 105%. The detection limits were 5μg/kg(l) in pig muscle, chicken muscle, fish and milk, 10μg/kg in kidney and 20μg/kg in egg, respectively. Chemiluminescence assay was developed for detecting neomycin residues in pig muscle and chicken muscle. The limit of detection of the method was 0.015μg/kg, and the detection limits were 1.5μg/kg in pig muscle and 6μg/kg in chicken muscle. The ELISA tests were validated by HPLC, and the results showed a good correlation (r(2)) which was greater than 0.9.

Legionella pollution in cooling tower water of air-conditioning systems in Shanghai, China

AIMS

To determine Legionella pollution prevalence, describe the amount of Legionellae with respect to temperature in Shanghai cooling tower water (CTWs) in various types of public sites.

METHODS AND RESULTS

Six urban districts were selected as the study fields, adopting multiple-phase sampling methods. Routine culture was used to identify Legionellae. Of the samples, 58.9% (189/321) were observed to be positive, 19.9% were isolated over 100 CFU ml(-1). Legionella pneumophila serogroup 1 was the most frequently isolated species (155/189, 82.0%), followed by Leg. micdadei that was at the second place (44/189, 23.3%). The mean CFU ml(-1) of Legionellae in CTWs reached its peak from July to September. Over all 15.4% of the samples exceeding 100 CFU ml(-1) were observed in a hospital setting.

CONCLUSIONS

The prevalence of Legionella pollution in CTWs, especially in CTWs of subway stations and hospitals, is worrying, and the positive rate and CFU ml(-1) of Legionellae in CTWs have a close relationship with air temperature.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study demonstrates pollution prevalence rates in different types of sites and various seasons, and provides a proportion of different serogroups of Legionellae. It illuminates an urgent need for dealing with the potential risk of legionellosis in Shanghai, through improved control and prevention strategies.

Delivery of ambulance service by volunteers in Victoria, Australia: an ethical dilemma?

The Alexandra District Ambulance Service is the only volunteer-based ambulance service in Victoria, Australia. It provides an opportunity to reflect on the ethical issues surrounding the delivery of ambulance service by volunteers, and its impact on the community.