Dissecting the Role of VicK Phosphatase in Aggregation and Biofilm Formation of Streptococcus mutans

VicRK (WalRK or YycFG) is a conserved 2-component regulatory system (TCS) that regulates cell division, cell wall biosynthesis, and homeostasis in low-GC Gram-positive bacteria. VicRK is also associated with biofilm formation of Streptococcus mutans on the tooth surface as it directly regulates the extracellular polysaccharide (EPS) synthesis. Of the 2 components, VicK possesses both autokinase and phosphatase activities, which regulate the phosphorylation and dephosphorylation of the regulator VicR in response to environmental cues. However, the dual mechanism of VicK as the autokinase/phosphatase in regulating S. mutans' responses is not well elucidated. Previously, it has been shown that the phosphatase activity depends on the PAS domain and residues in the DHp domain of VicK in S. mutans. Specifically, mutating proline at 222 in the PAS domain inhibits VicK phosphatase activity. We generated a VicK^P222A mutant to determine the level of VicR-P in the cytoplasm by Phos-tag sodium dodecyl sulfate polyacrylamide gel electrophoresis. We show that in VicK^P222A phosphatase, attenuation increased phosphorylated VicR (VicR-P) that downregulated glucosyltransferases, gtfBC, thereby reducing the synthesis of water-insoluble polysaccharides (WIS-EPS) in the biofilm. In addition, VicK^P222A presented as long-rod cells, reduced growth, and displayed asymmetrical division. A major adhesin of S. mutans, SpaP was downregulated in VicK^P222A, making it unable to agglutinate in saliva. In summary, we have confirmed that VicK phosphatase activity is critical to maintain optimal phosphorylation status of VicR in S. mutans, which is important for cell growth, cell division, EPS synthesis, and bacterial agglutination in saliva. Hence, VicK phosphatase activity may represent a promising target to modulate S. mutans' pathogenicity.

Abstract P6-17-15: Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models

Background

Until recently, HER2 gene amplification was the only mechanism of HER2 activation recognized. However, activating HER2 mutations have been noted in different cancer types. A trials of HER2 mutant breast cancer and the subsequent SUMMIT trial data have shown that monotherapy with the pan-HER drug neratinib as showed clinical efficacy, but with poor response durability. This study therefore investigates the preclinical efficacy of anti HER2 agents alone or in combination with endocrine therapy agents or in combination with CDK4/6 inhibitors using ER+/HER2 mutant cell lines and ex vivo HER2 mutant patient derived xenograft (PDX) model to define a more effective treatment approach.

Methods

ER+ breast cancer cell lines (T47D and MCF7) stably expressing HER2V777L, and ER+/HER2 mutant PDX model (HER2G778_P780 dup) were used to examine HER2 signaling and drug responses. Signaling downstream mutant HER2 was examined by immunoblot analysis. Effects of neratinib alone, neratinib + fulvestrant, and neratinib + abemaciclib on cell growth were examined in ER+/HER2 mutant cell lines and in an ex vivo HER2G778_P780 dup.

Results

We found that MCF7/T47D cells expressing HER2V777L and HER2G778_P780 dup PDX tumors showed strongly activated autophosphorylation of HER2 and increased expression of CDK4, CDK6, phospho-Rb, and cyclin D1 as compared to MCF7/T47D cells expressing HER2WT or ER+/non-HER2mut PDX modes, suggesting that HER2 mutations preferentially depend on CDK4/6 signaling for cell growth. Additionally, we showed that activating MCF7 HER2 V777L cause resistance to endocrine therapy treatment (fulvestrant IC50 >5μM). Further, we show that neratinib alone is effective at higher concentrations (IC50 < 2μM) in MCF7/HER2 V777L cells. We also demonstrate that abemaciclib alone exhibited moderate activity against MCF7 HER2 V777L cells (IC50 < 0.4μM) and additional activity in combination with neratinib (IC50 < 0.06μM) was seen. Moreover, ex vivo HER2 G778_P780 dup cells are relatively resistant to fulvestrant alone (IC50 < 0.2μM), neratinib alone (IC50 < 0.006μM), abemaciclib alone (IC50 < 0.04μM), and neratinib in combination with abemaciclib (IC50 < 0.005μM), suggesting that patients harboring ER+/HER2-mutant tumors may benefit from neratinib in combination with abemaciclib.

Conclusion

These preclinical data suggest that neratinib monotherapy may not be effective to treat ER+/HER2 mutant patients and we propose that simultaneous targeting of both HER2 and the CDK4/6 axis will be required for effective treatment of ER+ breast cancers harboring HER2 activating mutations.

Citation Format: Kavuri SM, Devarakonda V, Williams LC, Seker S, Lei JT, Singh P, Han A, Anurag M, Holloway KR, Welm AL, Ellis MJ. Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-15.

Abstract P5-08-01: DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer

Proteogenomics is the field of integrating data from mass spectrometry-based shotgun proteomics, and phosphoproteomics into next-generation RNA and DNA sequencing data analysis pipelines that promises new insights into cancer biology and therapeutic targeting. As well as analyses of clinical samples for disease phenotype association analysis, the application of proteogenomics to model systems also has considerable potential. A Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteogenomic analysis prioritized dihydropyrimidinase-like-3 (DPYSL3) as a multi-level (RNA/Protein/Phosphoprotein) expression outlier specific to the Claudin-Low (CLOW) subset of triple negative breast cancers. A Pubmed informatics tool indicated a paucity of data in the context of breast cancer which further prioritized DPYSL3 for study.

DPYSL3 was identified as a protein that is regulated during neuronal differentiation in the cerebral cortex and in neuronal cell lines and plays a role in regulating neurite outgrowth somehow through an association with vesicles in the growth cone. In addition, DPYSL3 expression has been observed in several malignant tumors, including prostate cancer, pancreatic cancer, gastric cancer and neuroblastoma. DPYSL3 is reported to play a role in cell migration and metastasis suppression in prostate cancer. However, in pancreatic cancer, DPYSL3 is positively associated with liver metastasis and poor outcome.

DPYSL3 knock-down in DPYSL3 (+) CLOW cell lines demonstrated reduced proliferation, yet enhanced motility and increased expression of Epithelial to Mesenchymal Transition (EMT) markers suggesting that DPYSL3 is a multi-functional signaling modulator. Slower proliferation in DPYSL3 (-) CLOW cells was associated with accumulation of multi-nucleated cells indicating a mitotic defect that was associated with a collapse of the vimentin (VIM) microfilament networkinduced by VIM hyperphosphorylation. On the other hand, DPYSL3 suppressed the expression of EMT regulators TWIST and SNAIL and opposed p21 activated kinase 2 (PAK2) dependent migration, but these EMT regulators in turn induced DPYSL3 expression, suggesting DPYSL3 participates in negative feedback in EMT. Cell migration in DPYSL3 (-) cells correlated with increased phosphorylation of PAK2 on Ser20 and was sensitive to PAK2 siRNA and pharmacological PAK inhibition.Immunoprecipitation and mass spectrometry-based proteomics or western blotting strongly suggests that PAKs interact such that DPYSL3 may function as a direct negative regulator of PAK family kinases. Thus, a PAK inhibitor could potentially mitigate increase migration as an adverse effect of DPYSL3 suppression.

In conclusion, DPYSL3 is a remarkable multifunctional signaling scaffold that should be examined further to provide insights into the stem cell-like state of claudin-low breast cancers, particularly in terms of their cell cycle dependencies, migratory activity and capacity for EMT.

Citation Format: Matsunuma R, Chan DW, Kim B-J, Singh P, Han A, Saltzman A, Cheng C, Lei JT, Sahin E, Leng M, Fan C, Perou CM, Malovannaya A, Ellis MJ. DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-08-01.

Macromolecular crowding tunes 3D collagen architecture and cell morphogenesis

Collagen I is the primary extracellular matrix component of most solid tumors and influences metastatic progression. Collagen matrix engineering techniques are useful for understanding how this complex biomaterial regulates cancer cell behavior and for improving in vitro cancer models. Here, we establish an approach to tune collagen fibril architecture using PEG as an inert molecular crowding agent during gelation and cell embedding. We find that crowding produces matrices with tighter fibril networks that are less susceptible to proteinase mediated degradation, but does not significantly alter matrix stiffness. The resulting matrices have the effect of preventing cell spreading, confining cells, and reducing cell contractility. Matrix degradability and fibril length are identified as strong predictors of cell confinement. Further, the degree of confinement predicts whether breast cancer cells will ultimately undergo individual or collective behaviors. Highly confined breast cancer cells undergo morphogenesis to form either invasive networks reminiscent of aggressive tumors or gland and lobule structures reminiscent of normal breast epithelia. This morphological transition is accompanied by expression of cell-cell adhesion genes, including PECAM1 and ICAM1. Our study suggests that cell confinement, mediated by matrix architecture, is a design feature that tunes the transcriptional and morphogenic state of breast cancer cells.

Analysis of Two Quantitative Ultrasound Approaches

There are two well-known ultrasonic approaches to extract sets of quantitative parameters: Lizzi-Feleppa (LF) parameters: slope, intercept, and midband; and quantitative ultrasound (QUS)-derived parameters: effective scatterer diameter (ESD) and effective acoustic concentration (EAC). In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD ([Formula: see text]), and from experimental data, LF midband is correlated to EAC ([Formula: see text]). However, LF intercept is not correlated to ESD ([Formula: see text]) nor EAC ([Formula: see text]). The unexpected correlation observed between LF slope and EAC ([Formula: see text]) results likely from the high correlation between ESD and EAC due to the inversion process. For a liver fat percentage estimation, an important potential medical application, the parameters presenting the better correlation are EAC ([Formula: see text]) and LF midband ([Formula: see text]).

Abstract P5-06-01: Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines

(Background) Patient-derived xenograft (PDX)s are valuable models for precision oncology as they are thought to recapitulate the biological and genomic characteristics of the human tumors they were derived from. Even though this model is widely used, it is still difficult to manipulate genes in this system and it is not as convenient as in vitro cell culture for drug sensitivity screening. On the other hand in vitro cell cultures have a highly artificial microenvironment and also have undergone selection which might generate misleading data. To address these issues cell lines from PDX tumors with different intrinsic subtypes were characterized by kinobead precipitation/mass spectrometry analysis (KiP/MS) to profile each PDX line in vivo and ex vivo for therapeutic targets.

(Materials and Methods)Washington University Human in Mice (WHIM) tumors and Hutsman Cancer Institute (HCI) tumors were transplanted into mammary fat pads of female severe combined immunodeficiency/beige (SCID/beige) mice. PDXs tumors were harvested when they reached 1˜1.5cm. PDX tumor-derived ex vivo cells/organoids were routinely cultured with Rock inhibitor support. Estradiol was applied only for the tumors originating from E2 supplementation in vivo. Cells and tumors were harvested and lysed by sonication. Kinases in soluble lysates are enriched with drug-bound beads (kinobead) and digested with trypsin. Digested peptides are analyzed by mass spectrometry.

(Results) 5 of WHIM tumors and 4 of HCI tumors were successfully dissociated and cultured ex vivo for further analysis and experiments. Hierarchical clustering of tumors and corresponding cells showed ex vivo cultured cells cluster together with their original PDX tumors. Tumors/ex vivo cultured cells clustered by intrinsic subtype and enrichment analysis identified specific kinases for each PDX tumor/cell line. The WHIM 4 tumor-cell pair showed high level of PIM kinase and EGFR and other PDX tumors such as WHIM18, WHIM 20 (Luminal subtypes), WHIM 35(HER2 enriched subtype) also showed model unique intrinsic kinases, such as JAK2 for WHIM18, EPHB4 for WHIM20.

(Conclusion) PDX tumor-derived ex vivo lines could be routinely cultured with Rock inhibitor support. Each PDX tumor and cell line pair were cluster together in hierarchical clustering and categorized into the same intrinsic subtype based on kinome profiling, suggesting these cells maintain their tumor specific intrinsic kinase signaling. A subset of kinases exhibit activity/expression that is conserved after ex vivo culture, we hypothesize these are intrinsic kinases might be promising target for treatment, because they are tumor intrinsic, i.e. their high expression is maintained despite the strong contrast in the microenvironment of in vitro versus in vitro growth. Ongoing studies with drugs and knock down reagents are examining whether the in vivo/ex vivo comparative KIP analysis indeed identifies therapeutic targets, which will be presented at the meeting more in detail.

Citation Format: Han A, Kim B-J, Chan DW, Matsunuma R, Singh P, Ellis MJ. Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-06-01.

3D collagen architecture induces a conserved migratory and transcriptional response linked to vasculogenic mimicry

The topographical organization of collagen within the tumor microenvironment has been implicated in modulating cancer cell migration and independently predicts progression to metastasis. Here, we show that collagen matrices with small pores and short fibers, but not Matrigel, trigger a conserved transcriptional response and subsequent motility switch in cancer cells resulting in the formation of multicellular network structures. The response is not mediated by hypoxia, matrix stiffness, or bulk matrix density, but rather by matrix architecture-induced β1-integrin upregulation. The transcriptional module associated with network formation is enriched for migration and vasculogenesis-associated genes that predict survival in patient data across nine distinct tumor types. Evidence of this gene module at the protein level is found in patient tumor slices displaying a vasculogenic mimicry (VM) phenotype. Our findings link a collagen-induced migration program to VM and suggest that this process may be broadly relevant to metastatic progression in solid human cancers.

Extracellular matrix plays a central role in driving cancer development. Here the authors using an in vitro approach show that confining collagen architectures induce fast and persistent cell migration and the formation of multicellular network structures linked to vascular mimicry observed in tumours from patients.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Impedance spectroscopy-based cell/particle position detection in microfluidic systems

An impedance spectroscopy-based cell/particle position detection method in microfluidic systems is presented. A single pair of non-parallel surface microelectrodes was utilized to detect the transverse positions of particles/cells flowing in a microchannel without the need for a multi-electrode multi-channel impedance detection. This method can be a simple solution for high-throughput and low-cost position detection in microfluidic sorting and separation applications.

Involved-field irradiation in definitive chemoradiotherapy for T4 squamous cell carcinoma of the esophagus

OBJECTIVES

Definitive concurrent chemoradiotherapy (ccrt) is currently a therapeutic option for locally advanced esophageal cancer. However, clinical practice differs with respect to the target volume for irradiation. The purpose of the present study was to analyze failure patterns and survival, and to determine the feasibility of using involved-field irradiation (ifi) with concurrent chemotherapy for T4 squamous cell carcinoma (scc) of the esophagus.

METHODS

Between January 2003 and January 2013, 56 patients with clinical T4M0 scc of the esophagus received ccrt using ifi. The radiation field included the primary tumour and clinically involved lymph nodes. Target volumes and sites of failure were analyzed, as were treatment-related toxicity and survival time.

RESULTS

In this 56-patient cohort, 13 patients (23.2%) achieved a complete response, and 21 (37.5%) achieved a partial response, for a total response rate of 60.7%. The major toxicities experienced were leucocytopenia and esophagitis, with 14 patients (25.0%) experiencing grade 3 toxicities. At a median follow-up of 34 months, 48 patients (85.7%) had experienced failure: 39 (69.6%) in-field, 7 (12.5%) elective nodal, and 19 (33.9%) distant. Only 1 patient (1.8%) experienced isolated elective nodal failure. The 1-, 2-, and 3-year survival rates were 39.3%, 21.4%, and 12.5% respectively.

CONCLUSIONS

For patients with T4M0 scc of the esophagus, definitive ccrt using ifi resulted in an acceptable rate of isolated elective nodal failure and an overall survival comparable to that achieved with elective nodal irradiation. A limited radiation therapy target volume, including only clinically involved lesions, would therefore be a feasible choice for this patient subgroup.

Biased signalling and proteinase-activated receptors (PARs): targeting inflammatory disease

Although it has been known since the 1960s that trypsin and chymotrypsin can mimic hormone action in tissues, it took until the 1990s to discover that serine proteinases can regulate cells by cleaving and activating a unique four-member family of GPCRs known as proteinase-activated receptors (PARs). PAR activation involves the proteolytic exposure of its N-terminal receptor sequence that folds back to function as a 'tethered' receptor-activating ligand (TL). A key N-terminal arginine in each of PARs 1 to 4 has been singled out as a target for cleavage by thrombin (PARs 1, 3 and 4), trypsin (PARs 2 and 4) or other proteases to unmask the TL that activates signalling via Gq , Gi or G12 /13 . Similarly, synthetic receptor-activating peptides, corresponding to the exposed 'TL sequences' (e.g. SFLLRN-, for PAR1 or SLIGRL- for PAR2) can, like proteinase activation, also drive signalling via Gq , Gi and G12 /13 , without requiring receptor cleavage. Recent data show, however, that distinct proteinase-revealed 'non-canonical' PAR tethered-ligand sequences and PAR-activating agonist and antagonist peptide analogues can induce 'biased' PAR signalling, for example, via G12 /13 -MAPKinase instead of Gq -calcium. This overview summarizes implications of this 'biased' signalling by PAR agonists and antagonists for the recognized roles the PARs play in inflammatory settings.

Pathway-selective antagonism of proteinase activated receptor 2

BACKGROUND AND PURPOSE

Proteinase activated receptor 2 (PAR2) is a GPCR associated with inflammation, metabolism and disease. Clues to understanding how to block PAR2 signalling associated with disease without inhibiting PAR2 activation in normal physiology could be provided by studies of biased signalling.

EXPERIMENTAL APPROACH

PAR2 ligand GB88 was profiled for PAR2 agonist and antagonist properties by several functional assays associated with intracellular G-protein-coupled signalling in vitro in three cell types and with PAR2-induced rat paw oedema in vivo.

KEY RESULTS

In HT29 cells, GB88 was a PAR2 antagonist in terms of Ca(2+) mobilization and PKC phosphorylation, but a PAR2 agonist in attenuating forskolin-induced cAMP accumulation, increasing ERK1/2 phosphorylation, RhoA activation, myosin phosphatase phosphorylation and actin filament rearrangement. In CHO-hPAR2 cells, GB88 inhibited Ca(2+) release, but activated G(i/o) and increased ERK1/2 phosphorylation. In human kidney tubule cells, GB88 inhibited cytokine secretion (IL6, IL8, GM-CSF, TNF-α) mediated by PAR2. A rat paw oedema induced by PAR2 agonists was also inhibited by orally administered GB88 and compared with effects of locally administered inhibitors of G-protein coupled pathways.

CONCLUSIONS AND IMPLICATIONS

GB88 is a biased antagonist of PAR2 that selectively inhibits PAR2/G(q/11)/Ca(2+)/PKC signalling, leading to anti-inflammatory activity in vivo, while being an agonist in activating three other PAR2-activated pathways (cAMP, ERK, Rho) in human cells. These findings highlight opportunities to design drugs to block specific PAR2-linked signalling pathways in disease, without blocking beneficial PAR2 signalling in normal physiology, and to dissect PAR2-associated mechanisms of disease in vivo.

Abstract P6-06-25: Usefulness of pretreatment NLR as prognostic factor of late recurrence, 5-year after primary treatment

Background

Prognostic factor and predictive factors are well established in early-stage breast cancer, but less is known about recurrence, especially 5-year after primary treatment. While mortality of breast cancer is from organic dysfunction with metastatic disease, not from the diseased breast itself, still we do not have adequate information about metastatic disease as we do about primary breast cancer itself.

The aim of this study is to investigate of usefulness of pretreatment NLR(neutrophil to lymphocyte ratio) as prognostic factor that can tell risk of recurrence 5- year after primary treatment.

Patients and methods

A retrospective review of invasive breast cancer patients surgically resected between January 2001 and December 2007. Exclusion criteria were as followings: patients with recurrence or death within 5yrs.

Results

A total of 301 patients were included and 13 patients experienced with recurrence after 5 years.

Table 1. Patients' characteristics Total (n = 301) N (%)Age*48.8(±11.4)Age ≤3525(8.3)35&lt; ≤50165(54.8)50&lt;111(36.9)Histology Ductal270(89.7)Lobular7(2.3)Others24(8.0)Tumor size (cm)*2.73(±1.64)T stage T1126(41.9)T2158(52.5)T317(5.6)N stage N0199(66.1)N167(22.3)N220(6.6)N311(3.7)unknown4(1.3)Histologic grade I72(23.9)II110(36.5)III70 (23.3)unknown49(16.3)Estrogen receptor Negative111(36.9)Positive185(61.5)unknown5(1.6)Progesterone receptor Negative129(42.9)Positive167(55.5)Unknown5(1.6)HER-2 Negative196(65.1)Positive98(32.6)unknown7(2.3)Molecular subtype Luminal A136(45.2)Luminal B66(21.9)HER-2 enriched32(10.6)Triple negative60(20.0)unknown7(2.3)Late recur Yes13(4.3)No288(95.7)*mean±SD

Overall average of NLR value was 2.16, median value was 1.83. The average NLR were 2.80±1.68 in patients with recurrences occurred after 5 years and 2.13±1.15 in patients without recurrence. The NLR cutoff value of 1.83 was determined by median value.

In 1.83≤NLR group has a higher incidence of recurrence after 5 years compared with NLR&lt;1.83 group (8yr DFS 99.2% vs. 93.3%, p = 0.021). Especially in luminal A(ER (+) or PR (+), HER-2(-)), 1.83≤NLR group has a higher incidence of recurrence after 5 years compared with NLR&lt;1.83 group (8yr DFS 100% vs. 87.0%, p = 0.015).

Conclusion

We found that pretreatment NLR is associated with late recurrence that occurs after five years. And we suggest that NLR could be used as one of the prognostic factor that can tell about late recurrence, 5-year after primary treatment.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-25.

Effects of maltitol and xylitol chewing-gums on parameters involved in dental caries development

AIM

The effects on plaque parameters of sugar free chewing-gums (CG) sweetened with either maltitol or xylitol were assessed to better understand the role polyols can play in dental caries prevention.

MATERIALS AND METHODS

A double-blind, parallel, randomised, controlled study was conducted in China. Subjects (N = 258, age = 13 to 15 years-old) were divided into 4 groups: 2 receiving polyols CG, containing respectively maltitol or xylitol, a group receiving gum base (placebo) and a negative control group not receiving any gum. CG were chewed for 30 days. This corresponds to a 10 g consumption of polyol per day. Plaque parameters (growth, pH, bacteria and insoluble glucans) were evaluated throughout the experimental period.

RESULTS

All parameters studied were significantly modified with gum base compared to no-gum: plaque pH increased; plaque growth, bacteria (S. mutans, S. sobrinus, A. viscosus and Lactobacillus) and insoluble glucans decreased. Maltitol and xylitol CG led similarly to a higher plaque pH (AUC, p⋜0.05) on short (at baseline after the first CG consumption) and long term (after 4 weeks of daily CG consumption), with or without saliva stimulation compared to both control and placebo groups. They led to a decrease in plaque growth (p=0.02) over the experimental period compared to controls. Moreover, they significantly reduced the concentration of 4 cariogenic bacteria species (p⋜0.05) in dental plaque compared to gum base.

CONCLUSION

Sugar free CG sweetened with either maltitol or xylitol can similarly reduce plaque acidogenicity compared to gum base through a decrease in oral bacteria presence. The use of a gum base placebo allowed to isolate effects on parameters involved in dental caries development specific to maltitol and xylitol, and to show these effects were similar.

Abstract P6-07-40: Initial Neutrophil-to-Lymphocyte ratio in primary breast cancer patients: a simple and useful biomarker as prognostic factor

Background: Increasing neutrophil/lymphocyte ratios (NLR) on preoperative blood tests have been associated with worse survival of patients with colorectal, gastric, hepatocellular, pancreatic and lung cancer. However the utility of NLR to predict mortality in breast cancer patients has not been studied. The aim of our study was to determine whether the NLR is predictive of disease specific mortality in breast cancer and subtype-adjusted prognostic effect in breast cancer patients.

Methods: We retrospectively identified all the patients with primary breast cancer diagnosed at Yonsei University Wonju Medical School between January 2000 and June 2011 who underwent primary surgery and completed all phase of their treatment. Breast cancer with infiltrating ductal histology was included and divided into 4 subtypes: Luminal A, Luminal B, Her2-enriched, and basal type. Each immunohistochemical characteristics are as followings: Luminal A: ER and/or PgR positive and negative Her2, Luminal B: ER and/or PgR positive with positive HER2, Her2-enriched: negative ER and PR with positive Her2, and triple negative as basal.

Results: Patients with NLR≥2.5 showed significantly lower 5-year, 10-year breast cancer specific survival than patients with NLR&lt;2.5. (5-year survival; 88.6% vs. 96.4%, p = 0.009, 10-year survival; 84.3% vs. 92.2%, p = 0.006). Cox proportional multivariate hazard model for cancer-specific mortality showed that patients with NLR≥2.5 has hazard ratio 4.71 with 95% confidence interval 1.77–12.53. Further analysis was done according to stratified patients' subgroup with intrinsic subtype. In Luminal A subtype, patients with NLR≥2.5 showed higher mortality rate(p = 0.014), while NLR≥2.5 failed to show statistical significance in the other subtype such as Luminal B, Her2 enriched, and triple negative subtype.

Conclusion: Increased preoperative NLR is a significant prognostic factor in breast cancer specific survival and relevant in Luminal A subtype. This study shows that NLR could be a useful prognostic factor for breast cancer specific survival. And this study suggests that different factors could contribute as prognostic factor to each subtype, such as NLR was significant prognostic factor in Luminal A, while we couldn't find increased NLR is significant in other subtypes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-40.

Effects of the addition of electrolyte on liquid infiltration in a hydrophobic nanoporous silica gel

In this letter, we report the experimental results of pressure induced infiltration in the hydrophobic nanopores of a silica gel. The infiltration pressure increases with the prolonged surface treatment time, whereas the infiltration volume is not dependent on the surface coverage. When temperature increases, if the liquid phase is pure water, the infiltration pressure would decrease, which is in agreement with the classic contact angle measurement results at large solid surfaces. As an electrolyte is added, however, the variation in infiltration pressure is negligible over a broad temperature range.

Upper sphincter function during transient lower oesophageal sphincter relaxation (tLOSR); it is mainly about microburps

Transient lower oesophageal sphincter relaxations (tLOSRs) are both a dominant mechanism of reflux and an element of the belch reflex. This study aimed to analyse the interplay between reflux and upper oesophageal sphincter (UOS) activity during meal-induced tLOSRs. Fifteen normal subjects were studied with a solid-state high-resolution manometry assembly positioned to record from the hypopharynx to the stomach and a catheter pH electrode 5 cm above the LOS. Subjects ate a 1000-calorie high-fat meal and were monitored for 120 min in a sitting posture. The relationship among tLOSRs, common cavities, pressure changes within the oesophagus and UOS contractile activity were analysed. A total of 218 tLOSRs occurred among the 15 subjects. The majority (79%) were coupled with UOS relaxation and 84% (145/173) of these occurred in association with a common cavity. Upper oesophageal sphincter relaxation was usually preceded by a pressure change in the oesophagus; however, some relaxations (16%) occurred without a discernable increase in pressure or before the pressure increase began. Acid reflux did not appear to play a role in determining UOS response to tLOSRs. The majority of post-prandial tLOSRs were associated with brief periods of UOS relaxation, likely permissive of gas venting (microburps). Intraoesophageal pressure changes likely modulate this UOS response; however, an anticipatory characteristic was evident in some subjects. Whether or not GORD patients with extra-oesophageal symptoms exhibit an exaggeration of the UOS relaxation response during reflux is yet to be determined.

Use of army weapons and private firearms for suicide and homicide in the region of Basel, Switzerland

OBJECTIVES

Switzerland has one of the highest rates of firearm suicides in the world. International studies show a positive correlation between the rate of households with guns and femicides with guns. Because its defense system requires a militia to keep personal firearms at home, Switzerland has a high rate of households with a gun.

METHODS

Records of suicides in the region of Basel between 1992 and 1996 were reviewed. Suicides with either army weapons or private firearms and suicides by other means were compared. Methods and types of homicides that occurred in the region at the same time were also analyzed.

FINDINGS

Firearm suicides were clearly the most frequent means of suicide. They were also used in 30.0% of domestic homicides, although other means were used at similar rates. Firearms for suicide were mainly used by men, especially army weapons. These men were younger, professionally better qualified, and fewer had ever been treated in one of the local state psychiatric services.

DISCUSSION

The use of firearms for suicide, rather than homicide, and particularly of army weapons by young, well-educated men, requires more attention in debates and informed policy regarding access to firearms and suicide prevention in Switzerland.

Tai chi for treating rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory autoimmune disease that results in the destruction of the musculoskeletal system. The major goals of treatment are to relieve pain, reduce inflammation, slow down or stop joint damage, prevent disability, and preserve or improve the person's sense of well-being and ability to function. Tai Chi, interchangeably known as Tai Chi Chuan, is an ancient Chinese health-promoting martial art form that has been recognized in China as an effective arthritis therapy for centuries.

OBJECTIVES

To assess the effectiveness and safety of Tai Chi as a treatment for people with RA.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (CCTR), MEDLINE, Pedro and CINAHL databases up to September 2002, using the Cochrane Collaboration search strategy for randomised controlled trials. We also searched the Chinese Biomedical Database up to December 2003 and the Beijing Chinese Academy of Traditional Medicine up to December 2003.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials examining the benefits and harms of exercise programs with Tai Chi instruction or incorporating principles of Tai Chi philosophy were selected. We included control groups who received no therapy, sham therapy or another type of therapy.

DATA COLLECTION AND ANALYSIS

Two reviewers determined the studies to be included in this review, rated the methodological quality and extracted data using standardized forms.

MAIN RESULTS

Four trials including 206 participants, were included in this review. Tai Chi-based exercise programs had no clinically important or statistically significant effect on most outcomes of disease activity, which included activities of daily living, tender and swollen joints and patient global overall rating. For range of motion, Tai Chi participants had statistically significant and clinically important improvements in ankle plantar flexion. No detrimental effects were found. One study found that compared to people who participated in traditional ROM exercise/rest programs those in a Tai Chi dance program reported a significantly higher level of participation in and enjoyment of exercise both immediately and four months after completion of the Tai Chi program.

REVIEWERS' CONCLUSIONS

The results suggest Tai Chi does not exacerbate symptoms of rheumatoid arthritis. In addition, Tai Chi has statistically significant benefits on lower extremity range of motion, in particular ankle range of motion, for people with RA. The included studies did not assess the effects on patient-reported pain.