Single-cell analysis of dorsal root ganglia reveals metalloproteinase signaling in satellite glial cells and pain

Satellite glial cells (SGCs) are among the most abundant non-neuronal cells in dorsal root ganglia (DRGs) and closely envelop sensory neurons that detect painful stimuli. However, little is still known about their homeostatic activities and their contribution to pain. Using single-cell RNA sequencing (scRNA-seq), we were able to obtain a unique transcriptional profile for SGCs. We found enriched expression of the tissue inhibitor metalloproteinase 3 (TIMP3) and other metalloproteinases in SGCs. Small interfering RNA and neutralizing antibody experiments revealed that TIMP3 modulates somatosensory stimuli. TIMP3 expression decreased after paclitaxel treatment, and its rescue by delivery of a recombinant TIMP3 protein reversed and prevented paclitaxel-induced pain. We also established that paclitaxel directly impacts metalloproteinase signaling in cultured SGCs, which may be used to identify potential new treatments for pain. Therefore, our results reveal a metalloproteinase signaling pathway in SGCs for proper processing of somatosensory stimuli and potential discovery of novel pain treatments.

Major depression-related factor NEGR1 controls salivary secretion in mouse submandibular glands

Salivary gland cells, which secrete water in response to neuronal stimulation, are closely connected to other neurons. Transcriptomic studies show that salivary glands also express some proteins responsible for neuronal function. However, the physiological functions of these common neuro-exocrine factors in salivary glands are largely unknown. Here, we studied the function of Neuronal growth regulator 1 (NEGR1) in the salivary gland cells. NEGR1 was also expressed in mouse and human salivary glands. The structure of salivary glands of Negr1 knockout (KO) mice was normal. Negr1 KO mice showed tempered carbachol- or thapsigargin-induced intracellular Ca²⁺ increases and store-operated Ca²⁺ entry. Of interest, the activity of the large-conductance Ca²⁺-activated K⁺ channel (BK channel) was increased, whereas Ca²⁺-activated Cl^- channel ANO1 channel activity was not altered in Negr1 KO mice. Pilocarpine- and carbachol-induced salivation was decreased in Negr1 KO mice. These results suggest that NEGR1 influence salivary secretion though the muscarinic Ca²⁺ signaling.

Circulation Time-Optimized Albumin Nanoplatform for Quantitative Visualization of Lung Metastasis via Targeting of Macrophages

The development of molecular imaging probes to identify key cellular changes within lung metastases may lead to noninvasive detection of metastatic lesions in the lung. In this study, we constructed a macrophage-targeted clickable albumin nanoplatform (CAN) decorated with mannose as the targeting ligand using a click reaction to maintain the intrinsic properties of albumin in vivo. We also modified the number of mannose molecules on the CAN and found that mannosylated serum albumin (MSA) harboring six molecules of mannose displayed favorable pharmacokinetics that allowed high-contrast imaging of the lung, rendering it suitable for in vivo visualization of lung metastases. Due to the optimized control of functionalization and surface modification, MSA enhanced blood circulation time and active/passive targeting abilities and was specifically incorporated by mannose receptor (CD206)-expressing macrophages in the metastatic lung. Moreover, extensive in vivo imaging studies using single-photon emission computed tomography (SPECT)/CT and positron emission tomography (PET) revealed that blood circulation of time-optimized MSA can be used to discern metastatic lesions, with a strong correlation between its signal and metastatic burden in the lung.

Novel regulation of the transcription factor ZHX2 by N-terminal methylation

N-terminal methylation (Nα-methylation) by the methyltransferase NRMT1 is an important post-translational modification that regulates protein-DNA interactions. Accordingly, its loss impairs functions that are reliant on such interactions, including DNA repair and transcriptional regulation. The global loss of Nα-methylation results in severe developmental and premature aging phenotypes, but given over 300 predicted substrates, it is hard to discern which physiological substrates contribute to each phenotype. One of the most striking phenotypes in NRMT1 knockout (Nrmt1^-/-) mice is early liver degeneration. To identify the disrupted signaling pathways leading to this phenotype and the NRMT1 substrates involved, we performed RNA-sequencing analysis of control and Nrmt1^-/- adult mouse livers. We found both a significant upregulation of transcripts in the cytochrome P450 (CYP) family and downregulation of transcripts in the major urinary protein (MUP) family. Interestingly, transcription of both families is inversely regulated by the transcription factor zinc fingers and homeoboxes 2 (ZHX2). ZHX2 contains a non-canonical NRMT1 consensus sequence, indicating that its function could be directly regulated by Nα-methylation. We confirmed misregulation of CYP and MUP mRNA and protein levels in Nrmt1^-/- livers and verified NRMT1 can methylate ZHX2 in vitro. In addition, we used a mutant of ZHX2 that cannot be methylated to directly demonstrate Nα-methylation promotes ZHX2 transcription factor activity and target promoter occupancy. Finally, we show Nrmt1^-/- mice also exhibit early postnatal de-repression of ZHX2 targets involved in fetal liver development. Taken together, these data implicate ZHX2 misregulation as a driving force behind the liver phenotype seen in Nrmt1^-/- mice.

Comparative analysis of the oral microbiome of burning mouth syndrome patients

Burning mouth syndrome (BMS) is a chronic pain condition accompanied by unpleasant burning sensations of the oral mucosa. While multiple factors were proposed for the etiology, evidence suggested a neuropathic pain origin while others suspected the use of antibiotics as the underlying cause. Interestingly, several reports demonstrated the intimate interaction of the nervous system and the microbiome. The current study aims to elucidate the correlation of the oral microbiome with the pathophysiology of the primary BMS. Microbiome samples obtained from the unstimulated whole saliva of 19 primary BMS patients and 22 healthy controls were sequenced and analyzed of the V3-V4 region of 16S rRNA gene. There was a distinct difference in the microbial composition between the BMS and the control groups at all taxonomic levels. Alpha diversity indexes of the oral microbiome were significantly lower in the BMS group. The samples were readily distinguished by multidimensional scaling analysis and linear discriminant analysis effect size. Streptococcus, Rothia, Bergeyella, and Granulicatella genus were dominant in the BMS group, while Prevotella, Haemophilus, Fusobacterium, Campylobacter, and Allorevotella genus were more abundant in the healthy group. Distinct microbiome signatures of BMS patients suggested a diagnostic value and a potential role in the pathogenesis of BMS.

  

Estrogen-dependent regulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3): Implication in burning mouth syndrome

Sex differences in the nervous system have gained recent academic interest. While the prominent differences are observed in mood and anxiety disorders, growing number of evidences also suggest sex difference in pain perception. This review focuses on estrogen as the key molecule underlying such difference, because estrogen plays many functions in the nervous system, including modulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3), two important nociceptive receptors. Estrogen was shown in various studies to up-regulate TRPV1 expression through two distinct pathways, resulting in pro-nociceptive effect. However, estrogen alleviated pain in other studies, by down-regulating nerve growth factor (NGF)-activated pathways and TRPV1. Estrogen may also attenuate nociception by inhibiting P2X3 receptors and ATP-signaling. Understanding the mechanism underlying the pro- and anti-nociceptive effect of estrogen might be crucial to understand pathophysiology of the burning mouth syndrome (BMS), a common chronic orofacial pain disorder in menopausal women. The involvement of TRPV1 is strongly suspected because of burning sensation. Reduced estrogen level of the BMS patient might have caused increased activity of P2X3 receptors. Interestingly, the increased expression of TRPV1 and P2X3 in oral mucosa of BMS patients was reported. The combinational impact of differential modulation of TRPV1/P2X3 during menopause might be an important contributing factor of etiology of BMS. Understanding the estrogen-dependent regulation of nociceptive receptors may provide a valuable insight toward the peripheral mechanism of sex-difference in pain perception.

Long-term efficacy and patient satisfaction of pulsed radiofrequency therapy in temporomandibular disorders: A randomized controlled trial

BACKGROUND

Pulse radiofrequency (PRF) therapy is one of effective physical therapy modalities for treat temporomandibular disorders (TMD). This prospective randomized controlled trial aimed to evaluate the long-term treatment efficacy and patient satisfaction with PRF therapy in TMD.

METHODS

Eighty-six female patients with TMD were randomly assigned to either pulsed radiofrequency or placebo therapy in combination with other conventional treatments once a week for 12 weeks. A final analysis was performed 12 weeks after the completion of treatment. Clinical parameters and patient satisfaction were analyzed at baseline, 4, 8, and 12 weeks of intervention and at 24 weeks from baseline.

RESULTS

Pain intensity, comfortable and maximum mouth opening, and pain on capsule and masticatory muscle palpation were significantly improved after treatment in both groups. Notably, the pulsed radiofrequency group showed a significantly lower pain intensity at the final evaluation performed 3 months after the completion of treatment. Significantly more patients reported subjective pain improvement and satisfaction with treatment following intervention at baseline in the PRF group. Most patients did not report any discomfort following treatment in either group. However, significantly more patients in the PRF group reported a burning sensation with intervention.

CONCLUSION

Long-term regular pulsed radiofrequency therapy was effective in significantly reducing TMD pain, and the effect was long-lasting following treatment completion. Pulsed radiofrequency therapy should be considered as a supportive physical therapy modality for TMD.

Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) peel and bulb extracts

Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl- 1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2'-azino-bis- 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H2O2 radical scavenging activity and Fe2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract's α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted.

Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set

BACKGROUND

A multi-cancer early detection (MCED) test used to complement existing screening could increase the number of cancers detected through population screening, potentially improving clinical outcomes. The Circulating Cell-free Genome Atlas study (CCGA; NCT02889978) was a prospective, case-controlled, observational study and demonstrated that a blood-based MCED test utilizing cell-free DNA (cfDNA) sequencing in combination with machine learning could detect cancer signals across multiple cancer types and predict cancer signal origin (CSO) with high accuracy. The objective of this third and final CCGA substudy was to validate an MCED test version further refined for use as a screening tool.

PATIENTS AND METHODS

This pre-specified substudy included 4077 participants in an independent validation set (cancer: n = 2823; non-cancer: n = 1254, non-cancer status confirmed at year-one follow-up). Specificity, sensitivity, and CSO prediction accuracy were measured.

RESULTS

Specificity for cancer signal detection was 99.5% [95% confidence interval (CI): 99.0% to 99.8%]. Overall sensitivity for cancer signal detection was 51.5% (49.6% to 53.3%); sensitivity increased with stage [stage I: 16.8% (14.5% to 19.5%), stage II: 40.4% (36.8% to 44.1%), stage III: 77.0% (73.4% to 80.3%), stage IV: 90.1% (87.5% to 92.2%)]. Stage I-III sensitivity was 67.6% (64.4% to 70.6%) in 12 pre-specified cancers that account for approximately two-thirds of annual USA cancer deaths and was 40.7% (38.7% to 42.9%) in all cancers. Cancer signals were detected across >50 cancer types. Overall accuracy of CSO prediction in true positives was 88.7% (87.0% to 90.2%).

CONCLUSION

In this pre-specified, large-scale, clinical validation substudy, the MCED test demonstrated high specificity and accuracy of CSO prediction and detected cancer signals across a wide diversity of cancers. These results support the feasibility of this blood-based MCED test as a complement to existing single-cancer screening tests.

CLINICAL TRIAL NUMBER

NCT02889978.

Functional Importance of Transient Receptor Potential (TRP) Channels in Neurological Disorders

Transient receptor potential (TRP) channels are transmembrane protein complexes that play important roles in the physiology and pathophysiology of both the central nervous system (CNS) and the peripheral nerve system (PNS). TRP channels function as non-selective cation channels that are activated by several chemical, mechanical, and thermal stimuli as well as by pH, osmolarity, and several endogenous or exogenous ligands, second messengers, and signaling molecules. On the pathophysiological side, these channels have been shown to play essential roles in the reproductive system, kidney, pancreas, lung, bone, intestine, as well as in neuropathic pain in both the CNS and PNS. In this context, TRP channels have been implicated in several neurological disorders, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and epilepsy. Herein, we focus on the latest involvement of TRP channels, with a special emphasis on the recently identified functional roles of TRP channels in neurological disorders related to the disruption in calcium ion homeostasis.

Dissolving Microneedles for Rapid and Painless Local Anesthesia

Microneedles are emerging drug delivery methods for painless treatment. The current study tested dissolving microneedles containing lidocaine (Li-DMN) for use in local anesthesia. An Li-DMN patch was fabricated by centrifugal lithography with carboxymethyl cellulose as a structural polymer and assessed for physical properties by optical microscopy and a fracture force analyzer. The biocompatibility was evaluated by a histology section in vitro and by ear thickness in vivo. The efficacy of the Li-DMN patch was assessed by electrophysiological recordings in primary cultured sensory neurons in vitro and a von Frey test on rats’ hind paws in vivo. The physical properties of the microneedle showed enough rigidity for transdermal penetration. The maximal capacity of lidocaine-HCl in the Li-DMN patch was 331.20 ± 6.30 µg. The cytotoxicity of the dissolving microneedle to neuronal cells was negligible under an effective dose of lidocaine for 18 h. Electrophysiological recordings verified the inhibitory effect of the voltage-gated sodium channel current by the Li-DMN patch in vitro. A skin reaction to the edema test and histologic analysis of the rats’ ears after application of the Li-DMN patch were negligible. Also, the application of the Li-DMN patch reduced the nocifensive behavior of the rats almost immediately. In conclusion, the dissolving microneedle patch with carboxymethyl cellulose is a promising candidate method for the painless delivery of lidocaine-HCl.

Ion Channels Involved in Tooth Pain

The tooth has an unusual sensory system that converts external stimuli predominantly into pain, yet its sensory afferents in teeth demonstrate cytochemical properties of non-nociceptive neurons. This review summarizes the recent knowledge underlying this paradoxical nociception, with a focus on the ion channels involved in tooth pain. The expression of temperature-sensitive ion channels has been extensively investigated because thermal stimulation often evokes tooth pain. However, temperature-sensitive ion channels cannot explain the sudden intense tooth pain evoked by innocuous temperatures or light air puffs, leading to the hydrodynamic theory emphasizing the microfluidic movement within the dentinal tubules for detection by mechanosensitive ion channels. Several mechanosensitive ion channels expressed in dental sensory systems have been suggested as key players in the hydrodynamic theory, and TRPM7, which is abundant in the odontoblasts, and recently discovered PIEZO receptors are promising candidates. Several ligand-gated ion channels and voltage-gated ion channels expressed in dental primary afferent neurons have been discussed in relation to their potential contribution to tooth pain. In addition, in recent years, there has been growing interest in the potential sensory role of odontoblasts; thus, the expression of ion channels in odontoblasts and their potential relation to tooth pain is also reviewed.

Critical Role of ATP-P2X7 Axis in UV-Induced Melanogenesis

Purinergic signaling participates in skin physiology and pathology, such as hair growth, wound healing, inflammation, pain, and skin cancer. However, few studies have investigated the involvement of purinergic signaling in skin pigmentation. This study demonstrated that extracellular adenosine 5'-triphosphate (ATP) released from keratinocytes by UVB radiation promotes melanin production in primary human epidermal melanocytes and ex vivo skin cultures. Intracellular calcium ion and protein kinase C/CREB signaling contributed to ATP-mediated melanogenesis. Also, P2X7 receptor was proven to play a pivotal role in ATP-mediated melanogenesis because P2X7 receptor blockade abrogated ATP-induced melanin production. In addition, MNT1 cells with P2X7 receptor knockout using CRISPR/Cas9 system did not show any increase in MITF expression when co-cultured with UV-irradiated keratinocytes compared to MNT1 cells with intact P2X7 receptor, which showed increased expression of MITF. In conclusion, our results indicate that the extracellular ATP-P2X7 signaling axis is an adjunctive mechanism in UV-induced melanogenesis. Furthermore, ATP-induced purinergic signaling in melanocytes may alter skin pigmentation.

Alzheimer's disease: insights for risk evaluation and prevention in the Chinese population and the need for a comprehensive programme in Hong Kong/China

With the ageing of the global population, China is projected to be impacted significantly by the rising number of patients with Alzheimer's disease (AD). A cure for AD is not yet available, so society should be prepared for an increasing AD-related burden. In this review, we examine this impending problem and provide overviews on (a) the magnitude of the problem of AD in Hong Kong/China in the near future; (b) the genetic and lifestyle risk factors that contribute to AD; (c) current diagnostic approaches and the potential of newly discovered genetic biomarkers for early detection; (d) medications, non-pharmacological interventions, and possible preventive measures; and (e) the need for social and psychological care from the community. In Hong Kong, primary care and AD-related support for at-risk individuals, patients, and caregivers are inadequate. A joint effort from the medical community, government, universities, non-governmental organisations/charities, and industry should initiate the development of a long-term programme for AD. Finally, we outline recommendations for the relevant parties to consider.

Human salivary gland cells express bradykinin receptors that modulate the expression of proinflammatory cytokines

Bradykinin is an important peptide modulator that affects the function of neurons and immune cells. However, there is no evidence of the bradykinin receptors and their functions in human salivary glands. Here we have identified and characterized bradykinin receptors on human submandibular gland cells. Both bradykinin B1 and B2 receptors are expressed on human submandibular gland cells, A253 cells, and HSG cells. Bradykinin increased the intracellular Ca²⁺ concentration ([Ca²⁺ ]_i ) in a concentration-dependent manner. Interestingly, a specific agonist of the B1 receptor did not have any effect on [Ca²⁺ ]_i in HSG cells, whereas specific agonists of the B2 receptor had a Ca²⁺ mobilizing effect. Furthermore, application of the B1 receptor antagonist, R715, did not alter the bradykinin-mediated increase in cytosolic Ca²⁺ , whereas the B2 receptor antagonist, HOE140, showed a strong inhibitory effect, which implies that bradykinin B2 receptors are functional in modulating the concentration of cytosolic Ca²⁺ . Bradykinin did not affect a carbachol-induced rise of [Ca²⁺ ]_i and did not modulate translocation of aquaporin-5. However, bradykinin did promote the expression of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), implying the role of bradykinin in salivary gland inflammation. These data suggest that bradykinin receptors are involved in Ca²⁺ signaling in human submandibular gland cells and serve a unique role, which is separate from that of other salivary gland G protein-coupled receptors.

Simulating real-life exposures to uncover possible risks to human health: A proposed consensus for a novel methodological approach

In real life, consumers are exposed to complex mixtures of chemicals via food, water and commercial products consumption. Since risk assessment usually focuses on individual compounds, the current regulatory approach doesn't assess the overall risk of chemicals present in a mixture. This study will evaluate the cumulative toxicity of mixtures of different classes of pesticides and mixtures of different classes of pesticides together with food additives (FAs) and common consumer product chemicals using realistic doses after long-term exposure. Groups of Sprague Dawley (CD-SD) rats (20 males and 20 females) will be treated with mixtures of pesticides or mixtures of pesticides together with FAs and common consumer product chemicals in 0.0, 0.25 × acceptable daily intake (ADI)/tolerable daily intake (TDI), ADI/TDI and 5 × ADI/TDI doses for 104 weeks. All animals will be examined every day for signs of morbidity and mortality. Clinical chemistry hematological parameters, serum hormone levels, biomarkers of oxidative stress, cardiotoxicity, genotoxicity, urinalysis and echocardiographic tests will be assessed periodically at 6 month intervals. At 3-month intervals, ophthalmological examination, test for sensory reactivity to different types of stimuli, together with assessment of learning abilities and memory performance of the adult and ageing animals will be conducted. After 24 months, animals will be necropsied, and internal organs will be histopathologically examined. If the hypothesis of an increased risk or a new hazard not currently identified from cumulative exposure to multiple chemicals was observed, this will provide further information to public authorities and research communities supporting the need of replacing current single-compound risk assessment by a more robust cumulative risk assessment paradigm.

Extracellular ATP Induces Calcium Signaling in Odontoblasts

Odontoblasts form dentin at the outermost surface of tooth pulp. An increasing level of evidence in recent years, along with their locational advantage, implicates odontoblasts as a secondary role as sensory or immune cells. Extracellular adenosine triphosphate (ATP) is a well-characterized signaling molecule in the neuronal and immune systems, and its potential involvement in interodontoblast communications was recently demonstrated. In an effort to elaborate the ATP-mediated signaling pathway in odontoblasts, the current study performed single-cell reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescent detection to investigate the expression of ATP receptors related to calcium signal in odontoblasts from incisal teeth of 8- to 10-wk-old rats, and demonstrated an in vitro response to ATP application via calcium imaging experiments. While whole tissue RT-PCR analysis detected P2Y₂, P2Y₄, and all 7 subtypes (P2X₁ to P2X₇) in tooth pulp, single-cell RT-PCR analysis of acutely isolated rat odontoblasts revealed P2Y₂, P2Y₄, P2X₂, P2X₄, P2X₆, and P2X₇ expression in only a subset (23% to 47%) of cells tested, with no evidence for P2X₁, P2X₃, and P2X₅ expression. An increase of intracellular Ca²⁺ concentration in response to 100μM ATP, which was repeated after pretreatment of thapsigargin or under the Ca²⁺-free condition, suggested function of both ionotropic and metabotropic ATP receptors in odontoblasts. The enhancement of ATP-induced calcium response by ivermectin and inhibition by 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) confirmed a functional P2X₄ subtype in odontoblasts. Positive calcium response to 2',3'-O-(benzoyl-4-benzoyl)-ATP (BzATP) and negative response to α,β-methylene ATP suggested P2X₂, P2X₄, and P2X₇ as functional subunits in rat odontoblasts. Single-cell RT-PCR analysis of the cells with confirmed calcium response and immunofluorescent detection further corroborated the expression of P2X₄ and P2X₇ in odontoblasts. Overall, this study demonstrated heterogeneous expression of calcium-related ATP receptor subtypes in subsets of individual odontoblasts, suggesting extracellular ATP as a potential signal mediator for odontoblastic functions.

Abstract P5-14-04: A phase 2 study evaluating orteronel, an inhibitor of androgen biosynthesis, in patients with androgen receptor (AR)-expressing metastatic breast cancer: Interim analysis

Background: The frequency of AR expression varies in the different breast cancer subtypes with 88%, 59%, and 32% expression reported in ER+, HER2+, and triple negative tumors, respectively. AR expression is associated with resistance to endocrine therapy in ER+ breast cancer. Androgen levels frequently increase following treatment with aromatase inhibitors suggesting a role for androgen synthesis inhibitors in ER+ breast cancer. AR signaling and expression are seen in triple negative breast cancer (TNBC), and a distinct AR TNBC subtype can be identified by gene expression profiling. AR expression in TNBC offers a potential therapeutic target. Preclinical and clinical studies demonstrated anti-androgen agent activity in breast cancer cell lines; preliminary clinical data suggests activity in TNBC. Orteronel is a novel, oral, selective, nonsteroidal inhibitor of 17, 20-lyase, a key enzyme in androgen biosynthesis that is being evaluated as endocrine therapy in various hormone-sensitive cancers. In this phase 2 study we are evaluating single agent orteronel in AR+ MBC.

Methods: Pts with AR expressing MBC (≥10% staining by central immunohistochemistry) were eligible. Pts were grouped into 2 cohorts for analysis: Cohort 1-TNBC and Cohort 2-ER+ (HER2 could be +/- in this cohort). Pts must have been previously treated with standard therapy for MBC (1-3 chemotherapy regimens for TNBC, 1-3 hormonal therapies + 1 chemotherapy for ER+ patients, ≥2 HER2-targeted regimens for HER2+ patients). A 6 pt lead-in for safety and tolerability of orteronel in AR+ female MBC pts was followed by open enrollment to either cohort. All pts received 300 mg orteronel PO BID over a 4 week cycle and underwent response assessment every 2 cycles. Treatment was continued until disease progression or unacceptable toxicity. The hypothesized response rate for Cohort 1 was 10% and 13% for Cohort 2. We present the results of a protocol-specified interim analysis of the ER+ MBC pts (Cohort 2).

Results: From 3/2014 to 4/2015, a total of 29 pts were enrolled on cohort 2. Median age was 65 years (range, 39-79); 90% ECOG ≤1; 90% HER2-/10% HER2+; median of 7 prior therapies (range 3-11). 93% had prior chemotherapy. Pts received a median of 2 cycles of orteronel treatment (range 1-4) and 3 pts (10%) are still on treatment. Of the 26 pts (90%) pts that have discontinued, 19 (66%) discontinued due to disease progression, 4 (14%) due to pt decision, 2 (7%) due to adverse event (AE), and 1 (3%) due to non-compliance. The most common treatment-related G 3/4 AEs were increased lipase [3 pts (10%)] and hypertension [2 pts (7%)]. There were no treatment-related SAEs or deaths on study. Three pts (10%) had stable disease as their best response. Further response evaluation is underway.

Conclusions: Orteronel monotherapy was well tolerated but appears to have limited single-agent activity in this heavily pre-treated ER+ MBC pt population. The full results from this interim analysis will be presented.

Citation Format: Yardley DA, Peacock N, Young RR, Silber A, Chung G, Webb CD, Jones SF, Shastry M, Midha R, DeBusk LM, Hainsworth JD, Burris HA. A phase 2 study evaluating orteronel, an inhibitor of androgen biosynthesis, in patients with androgen receptor (AR)-expressing metastatic breast cancer: Interim analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-14-04.

Desipramine inhibits salivary Ca(2+) signaling and aquaporin translocation

OBJECTIVE

Desipramine is a tricyclic antidepressant with a negative side effect of dry mouth. The Na(+) /H(+) exchanger was suggested to be a target of desipramine in salivary gland cells. However, it is unclear whether desipramine has other targets in the salivary secretion pathway. Here, we studied the effect of desipramine on salivary Ca(2+) signaling.

MATERIALS AND METHODS

Cytosolic free Ca(2+) concentration ([Ca(2+) ]i ) was determined with the fluorescent Ca(2+) indicator fura-2/AM. Aquaporin translocation was analyzed by Western blotting and immunocytochemistry of confocal microscopy.

RESULTS

Desipramine inhibited the carbachol- and histamine-mediated increase in cytosolic Ca(2+) ([Ca(2+) ]i ) in a concentration-dependent manner. However, desipramine did not affect increases in [Ca(2+) ]i mediated by extracellular ATP, sphingosine-1-phosphate, or thapsigargin. The adrenergic receptor blockers prazosin and propranolol did not reverse the desipramine-mediated inhibition of carbachol- and histamine-induced increases in [Ca(2+) ]i . We also found that desipramine inhibits the increase in membrane aquaporin-5 level triggered by carbachol and histamine treatments.

CONCLUSIONS

These results imply that desipramine blocks muscarinic and histamine receptor-mediated Ca(2+) signaling and the subsequent translocation of aquaporin-5 in human salivary gland cells, suggesting a novel mechanism for the xerogenic effects of desipramine.

Generation of resonance-dependent oscillation by mGluR-I activation switches single spiking to bursting in mesencephalic trigeminal sensory neurons

The primary sensory neurons supplying muscle spindles of jaw-closing muscles are unique in that they have their somata in the mesencephalic trigeminal nucleus (MTN) in the brainstem, thereby receiving various synaptic inputs. MTN neurons display bursting upon activation of glutamatergic synaptic inputs while they faithfully relay respective impulses arising from peripheral sensory organs. The persistent sodium current (IN aP ) is reported to be responsible for both the generation of bursts and the relay of impulses. We addressed how IN aP is controlled either to trigger bursts or to relay respective impulses as single spikes in MTN neurons. Protein kinase C (PKC) activation enhanced IN aP only at low voltages. Spike generation was facilitated by PKC activation at membrane potentials more depolarized than the resting potential. By injection of a ramp current pulse, a burst of spikes was triggered from a depolarized membrane potential whereas its instantaneous spike frequency remained almost constant despite the ramp increases in the current intensity beyond the threshold. A puff application of glutamate preceding the ramp pulse lowered the threshold for evoking bursts by ramp pulses while chelerythrine abolished such effects of glutamate. Dihydroxyphenylglycine, an agonist of mGluR1/5, also caused similar effects, and increased both the frequency and impedance of membrane resonance. Immunohistochemistry revealed that glutamatergic synapses are made onto the stem axons, and that mGluR1/5 and Nav1.6 are co-localized in the stem axon. Taken together, glutamatergic synaptic inputs onto the stem axon may be able to switch the relaying to the bursting mode.

Low levels of methyl β-cyclodextrin disrupt GluA1-dependent synaptic potentiation but not synaptic depression

Methyl-β-cyclodextrin (MβCD) is a reagent that depletes cholesterol and disrupts lipid rafts, a type of cholesterol-enriched cell membrane microdomain. Lipid rafts are essential for neuronal functions such as synaptic transmission and plasticity, which are sensitive to even low doses of MβCD. However, how MβCD changes synaptic function, such as N-methyl-d-aspartate receptor (NMDA-R) activity, remains unclear. We monitored changes in synaptic transmission and plasticity after disrupting lipid rafts with MβCD. At low concentrations (0.5 mg/mL), MβCD decreased basal synaptic transmission and miniature excitatory post-synaptic current without changing NMDA-R-mediated synaptic transmission and the paired-pulse facilitation ratio. Interestingly, low doses of MβCD failed to deplete cholesterol or affect α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R) and NMDA-R levels, while clearly reducing GluA1 levels selectively in the synaptosomal fraction. Low doses of MβCD decreased the inhibitory effects of NASPM, an inhibitor for GluA2-lacking AMPA-R. MβCD successfully decreased NMDA-R-mediated long-term potentiation but did not affect the formation of either NMDA-R-mediated or group I metabotropic glutamate receptor-dependent long-term depression. MβCD inhibited de-depression without affecting de-potentiation. These results suggest that MβCD regulates GluA1-dependent synaptic potentiation but not synaptic depression in a cholesterol-independent manner.

Single-cell RT-PCR and immunocytochemical detection of mechanosensitive transient receptor potential channels in acutely isolated rat odontoblasts

OBJECTIVE

Hydrostatic force applied to tooth pulp has long been suspected to be the direct cause of dental pain. However, the molecular and cellular identity of the transducer of the mechanical force in teeth is not clear. Growing number of literatures suggested that odontoblasts, secondary to its primary role as formation of tooth structure, might function as a cellular mechanical transducer in teeth.

DESIGN

In order to determine whether odontoblasts could play a crucial role in transduction of hydrostatic force applied to dental pulp into electrical impulses, current study investigated the expression of stretch-activated transient receptor potential (TRP) channels in acutely isolated odontoblasts from adult rats by single cell reverse transcriptase polymerase chain reaction and immunocytochemical analysis.

RESULTS

As the result, expression of TRPM7 (melastatin 7) was observed in majority (87%) of odontoblasts while mRNAs for TRPC1 (canonical 1), TRPC6 (canonical 6) and TRPV4 (vanilloid 4) were detected in small subpopulations of odontoblasts. TRPM3 (melastatin 3) was not detected in our experimental set-up. Immunocytochemical analysis further revealed TRPM7 expression at protein level.

CONCLUSION

Expression of the mechanosensitive TRP channels provides additional evidence that supports the sensory roles of odontoblasts. Given that TRPM7 is a mechanosensitive ion channel with a kinase activity that plays a role in Mg(2+) homeostasis, it is possible that TRPM7 expressed in odontoblasts might play a central role in mineralization during dentin formation.

Activation of transient receptor potential ankyrin 1 by eugenol

Eugenol is a bioactive plant extract used as an analgesic agent in dentistry. The structural similarity of eugenol to cinnamaldehyde, an active ligand for transient receptor potential ankyrin 1 (TRPA1), suggests that eugenol might produce its effect via TRPA1, in addition to TRPV1 as we reported previously. In this study, we investigated the effect of eugenol on TRPA1, by fura-2-based calcium imaging and patch clamp recording in trigeminal ganglion neurons and in a heterologous expression system. As the result, eugenol induced robust calcium responses in rat trigeminal ganglion neurons that responded to a specific TRPA1 agonist, allyl isothiocyanate (AITC), and not to capsaicin. Capsazepine, a TRPV1 antagonist failed to inhibit eugenol-induced calcium responses in AITC-responding neurons. In addition, eugenol response was observed in trigeminal ganglion neurons from TRPV1 knockout mice and human embryonic kidney 293 cell lines that express human TRPA1, which was inhibited by TRPA1-specific antagonist HC-030031. Eugenol-evoked TRPA1 single channel activity and eugenol-induced TRPA1 currents were dose-dependent with EC50 of 261.5μM. In summary, these results demonstrate that the activation of TRPA1 might account for another molecular mechanism underlying the pharmacological action of eugenol.

Abstract P3-14-02: Patterns of the use of primary systemic therapy in the United States

Background: Primary systemic therapy (PST) is an accepted alternative to adjuvant systemic therapy of breast cancer. It provides equivalent survival, increased breast conservation rates, and prognostic information.

Methods: This analysis assesses patterns of PST use based on information collected by the National Cancer Database (NCDB), a joint project of the American College of Surgeons and the American Cancer Society which captures data on over 70% of all diagnosed breast cancer patients in the U.S. Using the b-participant use file of the NCDB, we evaluated regional, patient, and tumor factors associated with PST use.

Results: The NCDB captured 621,319 patients treated with PST from 2006 to 2010. Of these, 7.4% received systemic therapy pre-operatively, and 3.6% in both the pre- and post-operative settings. Factors correlating with timing of therapy are shown in the table. PST use increased steadily from 7.0% to 7.8% (p<0.001) from 2006 to 2010. PST was significantly more frequently used in younger, African-American, Hispanic, low-income, uninsured patients with larger, node positive tumors, living in large metropolitan areas in the West and treated in academic centers. These factors remained significantly and independently associated with PST on multivariate analysis.

 UnivariateMultivariateFactorPre-opPost-opBothp-valuep-valueYear of Diagnosis   <0.001<0.00120067.0%90.0%3.0%  20077.1%89.5%3.4%  20087.2%89.2%3.6%  20097.6%88.6%3.8%  20107.8%87.7%4.5%  Region   <0.001<0.001Northeast5.7%90.9%3.4%  Atlantic6.7%90.4%2.9%  Southeast8.0%88.2%3.8%  Great Lakes6.5%90.1%3.4%  South7.7%88.4%3.9%  Midwest5.2%90.2%4.6%  West11.4%84.2%4.4%  Mountain8.8%88.7%2.5%  Pacific7.7%88.3%4.0%  Community type (pop):   <0.001<0.001Metro (>1M)7.9%88.3%3.8%  Metro (250K-1M)7.1%89.5%3.4%  Metro (<250K)6.3%90.5%3.2%  Urban, adjacent to a metro area (20K+)6.5%90.0%3.5%  Urban, not adjacent to metro (20K+)6.3%90.5%3.2%  Urban, adjacent to metro (2500-19,999)6.7%89.4%4.0%  Urban, not adjacent to metro (2500-19,999)6.0%90.6%3.4%  Rural/urban pop, adjacent to metro (<2500)6.0%90.3%3.8%  Rural/urban pop, not adjacent to metro (<2500)5.7%90.5%3.8%  Facility type:   <0.001<0.001Community program6.4%90.5%3.1%  Comprehensive community program7.1%89.5%3.5%  Academic/research8.4%87.4%4.2%  Other6.4%90.0%3.6%  Age:   <0.001<0.001<609.4%85.8%4.8%  ≥604.9%92.9%2.3%  Race:   <0.001<0.001Caucasian6.7%89.3%3.5%  African-American11.8%83.3%4.9%  Other8.4%87.5%4.1%  Ethnicity:   <0.001<0.001Non-Hispanic7.2%89.3%3.6%  Hispanic11.2%83.3%5.4%  Median household income:   <0.0010.023<$30K9.0%86.8%4.2%  $30K-$34,9997.7%88.6%3.7%  $35K-$45,9997.2%89.1%3.7%  $46K+6.9%89.6%3.4%  Insurance:   <0.001<0.001Uninsured15.3%78.1%6.6%  Private7.8%88.3%3.9%  Medicaid13.7%79.2%7.2%  Medicare4.8%93.0%2.2%  Military8.2%87.5%4.4%  Clinical T stage:   <0.001<0.001T12.4%96.4%1.2%  T213.6%79.5%6.9%  T3-T435.9%45.3%18.8%  Clinical N stage:   <0.001<0.001N04.8%92.9%2.3%  N1-326.0%60.3%13.7%  pop: population; multivariate OR and 95% CI not shown

Conclusion: PST appears to be underutilized, received by only 7.8% of all patients, 36% of T3-T4 tumors, and 26.0% of clinically node positive patients. However, its rate of use has increased over the past years. There is also significant regional variation in the use of PST, independent of patient and tumor factors.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-02.

Abstract P6-11-03: Follow up of breast cancer patients who underwent gamma knife radiosurgery for a diagnosis of brain metastases: A single institutional experience

Background: Breast cancer (BC) is the second most common cause of brain metastases in the United States. We performed a retrospective analysis of BC patients (pts) in the Yale Gamma Knife Radiosurgery (GKRS) database treated for brain metastases (mets) to report overall survival (OS) from time of GKRS, and to identify factors that predict improved survival outcomes.

Methods: We performed retrospective review of the Yale database of BC pts treated with standard GKRS technique for brain mets from 2000 to May 2013. Treatment doses typically ranged from 16 to 24 Gy prescribed to the 40-85% isodose surfaces. Overall survival (OS) for each patient was calculated from the date of first GKRS treatment of brain metastases. Variables included age, Karnofsky Performance Status (KPS), pre/post whole-brain radiation treatment (WBRT) and/or surgical resection, and # of brain mets treated (1-4 vs ≥5).

Results: A total of 80 BC pts were identified, with a mean age of 56.2 yrs; KPS 40-60 in 8pts (10%), 70-80 in 13 (16%), 90-100 in 41 (51%), unknown in 18 (23%); ER+ in 38 (48%), ER- in 38 (48%), unknown in 4 (5%); HER2 + in 38 (48%), HER2- in 33 (41%), indeterminate in 3 (4%) and unknown in 6 (8%). BC subtypes are Luminal A (ER+/HER2-) in 16 (20%), Luminal B (ER+/HER2+) in 19 (24%), HER-2(ER-/HER2+) in 17 (21%), Basal (ER-/HER2-) in 17 (21%), unknown in 11 (14%). Number of brain mets at time of first GKRS ≥5 in 32 (40%); prior WBRT in 30 (38%); WBRT post GKRS in 9 (11%); surgical resection for brain mets in 13 (16%) prior to GKRS and post GKRS in 9 (11%); 16% had ≥3 GKRS. Median time from primary BC dx to brain mets is 62.8 months (m) (range 46.2-81.6); with no significant difference among subtypes. Median OS from GKRS is 13.1 m (7.6-21.9); median OS from brain mets is 18.8 m (11.7-23.9). On univariate analysis, factors associated with significant improved OS from time of GKRS included HER-2 subtype (p = 0.005), KPS 90-100 (p = 0.008), good control of systemic disease (p = 0.017), pre (p = 0.041) and post GKRS surgical resection (p = 0.02). Age, pre or post WBRT, # of brain mets (1-4 vs. 5) were not significant predictors of OS from time of GKRS. In a multivariate Cox analysis (46 cases), HER-2 subtype remained a significant predictor of improved OS from time of GKRS; (HR) 0.26, 95%CI 0.08 to 0.8, p-value = 0.02. There was a trend in favor of surgical resection of brain mets pre GKRS (HR 0.14, 95% CI 0.02 to 1.15, p-value = 0.067

Conclusion: GKRS offers good local control for BC pts with brain mets, and is a reasonable option for pts with ≥5 brain mets. Our results show no associated survival benefit for administration of WBRT pre/post GKRS. HER-2 subtype is a significant predictor of improved survival in BC pts undergoing GKRS for brain mets.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-03.

Abstract P5-13-05: Richer and wiser: Factors correlated with chemoprevention use in the United States

Introduction: Tamoxifen and raloxifene have been shown to reduce the risk of breast cancer by up to 50%, yet the uptake of these agents remains poor. We sought to determine factors associated with chemoprevention uptake in a nationally representative sample.

Methods: The National Health Interview Survey (NHIS) is a population-based survey conducted annually by the CDC and is designed to be representative of the non-institutionalized civilian population in the United States. We utilized data from the 2010 NHIS cancer supplement to determine factors associated with chemoprevention uptake in women ≥ 35 years of age. Statistical analyses were conducted using SUDAAN software.

Results: In 2010, 10,959 women ≥ 35 years of age were surveyed, representing 83,377,082 people in the population. Of these, 0.21% reported taking chemoprevention, using either tamoxifen or raloxifene. On bivariate analyses, factors correlating with chemoprevention uptake included age, race/ethnicity, education, insurance, income and geographic region (see Table). Interestingly, MRI use, family history of premenopausal breast cancer in first degree relatives, and personal risk perception were not associated with chemoprevention use. On multivariate analysis, education and income remained independent predictors of chemoprevention use.

Conclusion: Approximately 0.2% of women take chemoprevention. It is concerning that sociodemographic factors of education and income are independent predictors of the use of chemopreventive agents for breast cancer, while risk perception and family history do not seem to correlate with uptake rates. These findings are a call to action for improved education and counseling of those who are at greatest risk, and highlight potential disparities in access to appropriate chemoprevention across all sociodemographic groups.

Bivariate and Multivariate Analyses of Factors Correlated with Chemoprevention UptakeFactorBivariate AnalysisMultivariate Analysis Chemoprevention (%)No Chemoprevention (%)p-valueOR (95% CI)p-valueAge  0.0481 0.1087< 40 yr3.2211.93 1.00 40-49 yr5.8726.11 0.78 (0.05-12.44) 50-59 yr11.7024.88 1.44 (0.10-21.43) 60-69 yr23.8218.54 3.15 (0.32-31.41) 70-79 yr44.4110.77 8.62 (0.78-94.75) 80+ yr10.997.77 1.53 (0.10-23.66) Race/ethnicity  0.0006 0.8372Hispanic3.9011.06 00.81 (0.11-5.85) White96.1071.63 1.00 Black011.80 - Asian04.61 - Other00.89 - Education  0.0371 <0.0001< Grade 127.1214.15 1.00 High School25.8627.73 1.86 (0.35-9.75) Some college/Assoc21.4229.97 1.85 (0.36-9.45) Bachelors15.5917.49 1.44 (0.13-16.35) Masters11.708.37 3.23 (0.41-25.14) Prof/Doctorate18.302.28 25.22 (4.30-147.87) Insurance  0.0002 0.0686Not covered012.44 - Medicare72.6129.38 1.00 Medicaid3.224.50 2.38 (0.22-26.15) Military01.74 - Private24.1751.94 0.28 (0.06-1.26) Income  0.0005 0.0306<$35K32.3934.53 1.00 $35K-$74,99926.1131.53 0.97 (0.21-4.42) $75K-$99,999012.08 - $100K+41.6021.86 3.78 (0.94-15.22) Region  0.0441 0.1649Northeast27.9318.62 1.00 Midwest31.6022.88 0.92 (0.32-2.64) South34.4935.66 0.65 (0.21-2.04) West5.9822.84 0.16 (0.03-0.86) Oophorectomy40.1115.160.08132.17 (0.77-6.09)0.1404MRI use2.315.170.2597  Family History2.315.130.2601  Risk Perception  0.1451  High41.5212.50   Average25.8947.49   Low32.5940.01   

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-05.

Pain fiber anesthetic reduces brainstem Fos after tooth extraction

We recently demonstrated that pain-sensing neurons in the trigeminal system can be selectively anesthetized by co-application of QX-314 with the TRPV1 receptor agonist, capsaicin (QX cocktail). Here we examined whether this new anesthetic strategy can block the neuronal changes in the brainstem following molar tooth extraction in the rat. Adult male Sprague-Dawley rats received infiltration injection of anesthetic 10 min prior to lower molar tooth extraction. Neuronal activation was determined by immunohistochemistry for the proto-oncogene protein c-Fos in transverse sections of the trigeminal subnucleus caudalis (Sp5C). After tooth extraction, c-Fos-like immunoreactivity (Fos-LI) detected in the dorsomedial region of bilateral Sp5C was highest at 2 hrs (p < .01 vs. naïve ipsilateral) and declined to pre-injury levels by 8 hrs. Pre-administration of the QX cocktail significantly reduced to sham levels Fos-LI examined 2 hrs after tooth extraction; reduced Fos-LI was also observed with the conventional local anesthetic lidocaine. Pulpal anesthesia by infiltration injection was confirmed by inhibition of the jaw-opening reflex in response to electrical tooth pulp stimulation. Our results suggest that the QX cocktail anesthetic is effective in reducing neuronal activation following tooth extraction. Thus, a selective pain fiber 'nociceptive anesthetic' strategy may provide an effective local anesthetic option for dental patients in the clinic.

Cellular and molecular mechanisms of dental nociception

Due, in part, to the unique structure of the tooth, dental pain is initiated via distinct mechanisms. Here we review recent advances in our understanding of inflammatory tooth pain and discuss 3 hypotheses proposed to explain dentinal hypersensitivity: The first hypothesis, supported by functional expression of temperature-sensitive transient receptor potential channels, emphasizes the direct transduction of noxious temperatures by dental primary afferent neurons. The second hypothesis, known as hydrodynamic theory, attributes dental pain to fluid movement within dentinal tubules, and we discuss several candidate cellular mechanical transducers for the detection of fluid movement. The third hypothesis focuses on the potential sensory function of odontoblasts in the detection of thermal or mechanical stimuli, and we discuss the accumulating evidence that supports their excitability. We also briefly update on a novel strategy for local nociceptive anesthesia via nociceptive transducer molecules in dental primary afferents with the potential to specifically silence pain fibers during dental treatment. Further understanding of the molecular mechanisms of dental pain would greatly enhance the development of therapeutics that target dental pain.

TRP Channels in Dental Pain

Despite the high incidence of dental pain, the mechanism underlying its generation is mostly unknown. Functional expression of temperature-sensitive transient receptor potential (thermo-TRP) channels, such as TRPV1, TRPV2, TRPM8, and TRPA1 in dental primary afferent neurons and TRPV1, TRPV2, TRPV3, TRPV4, and TRPM3 in odontoblasts, has been demonstrated and suggested as responsible for dental pain elicited by hot and cold food. However, dental pain induced by light touch or sweet substance cannot be explained by the role of thermo-TRP channels. Most of current therapeutics of dentin hypersensitivity is based on hydrodynamic theory, which argues that light stimuli such as air puff and temperature changes cause fluid movement within dentinal tubule, which is then transduced as pain. To test this theory, various TRP channels as candidates of cellular mechanotransducers were studied for expression in dental primary afferents and odontoblasts. The expression of TRPV1, TRPV2, TRPA1, TRPV4, and TRPM3 in trigeminal neurons and TRPV1, TRPV2, TRPV3, TRPV4 and TRPM3 in odontoblasts has been revealed. However, their roles as cellular mechanotransducers are controversial and contribution to generation of dental pain is still elusive. This review discusses recent advances in understanding of molecular mechanism underlying development of dental pain.

A Novel Carbamoyloxy Arylalkanoyl Arylpiperazine Compound (SKL-NP) Inhibits Hyperpolarization-Activated Cyclic Nucleotide-Gated (HCN) Channel Currents in Rat Dorsal Root Ganglion Neurons

In this study, we determined mode of action of a novel carbamoyloxy arylalkanoyl arylpiperazine compound (SKL-NP) on hyperpolarization-activated cyclic nucleotide-gated (HCN) channel currents (I(h)) that plays important roles in neuropathic pain. In small or medium-sized dorsal root ganglion (DRG) neurons (<40 µm in diameter) exhibiting tonic firing and prominent I(h), SKL-NP inhibited I(h) and spike firings in a concentration dependent manner (IC(50)=7.85 µM). SKL-NP-induced inhibition of I(h) was blocked by pretreatment of pertussis toxin (PTX) and N-ethylmaleimide (NEM) as well as 8-Br-cAMP, a membrane permeable cAMP analogue. These results suggest that SKL-NP modulates I(h) in indirect manner by the activation of a Gi-protein coupled receptor that decreases intracellular cAMP concentration. Taken together, SKL-NP has the inhibitory effect on HCN channel currents (I(h)) in DRG neurons of rats.

Neurochemical properties of dental primary afferent neurons

The long belief that dental primary afferent (DPA) neurons are entirely composed of nociceptive neurons has been challenged by several anatomical and functional investigations. In order to characterize non-nociceptivepopulation among DPA neurons, retrograde transport fluorescent dye was placed in upper molars of rats and immunohistochemical detection of peripherin and neurofilament 200 in the labeled trigeminal ganglia was performed. As the results, majority ofDPA neurons were peripherin-expressing small-sized neurons, showing characteristic ofnociceptive C-fibers. However, 25.7% of DPA were stained with antibody against neurofilament 200, indicating significant portion of DPA neurons are related to large myelinated Aβ fibers. There were a small number of neurons thatexpressed both peripherin and neurofilament 200, suggestive of Aδ fibers. The possible transition of neurochemical properties by neuronal injury induced by retrograde labeling technique was ruled out by detection of minimal expression of neuronal injury marker, ATF-3. These results suggest that in addition to the large population of C-fiber-related nociceptive neurons, a subset of DPA neurons is myelinated large neurons, which is related to low-threshold mechanosensitive Aβ fibers. We suggest that these Aβ fiber-related neurons might play a role as mechanotransducers of fluid movement within dentinal tubules.

Characterization of Dental Nociceptive Neurons

Selective blockade of nociceptive neurons can be achieved by the delivery of permanently charged sodium channel blockers through the pores of nociceptive ion channels. To assess the feasibility of this application in the dental area, we investigated the electrophysiological and neurochemical characteristics of nociceptive dental primary afferent (DPA) neurons. DPA neurons were identified within trigeminal ganglia labeling with a retrograde fluorescent dye applied to the upper molars of adult rats. Electrophysiological studies revealed that the majority of dental primary afferent neurons showed characteristics of nociceptive neurons, such as sensitivity to capsaicin and the presence of a hump in action potential. Immunohistochemical analysis revealed a large proportion of DPA neurons to be IB4-positive and to express TRPV1 and P2X3. Single-cell RT-PCR revealed mRNA expression of various nociceptive channels, including the temperature-sensitive TRPV1, TRPA1, TRPM8 channels, the extracellular ATP receptor channels P2X2 and P2X3, as well as the nociceptor-specific sodium channel, NaV1.8. In conclusion, DPA neurons have the electrophysiological characteristics of nociceptors and express several nociceptor-specific ion channels. Analysis of these data may assist in the search for a new route of entry for the delivery of membrane-impermeant local anesthetics. Abbreviations: AP, action potential; DiI, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate; DPA, dental primary afferent; FITC, fluorescein 5(6)-isothiocyanate; IB4, isolectin-B4; RT-PCR, reverse-transcription polymerase chain-reaction; TRP, transient receptor potential.

Abstract P3-14-17: Trastuzumab (H) and Rapamycin (R) for Treatment of HER-2 Overexpressing Metastatic Breast Cancer (BC) with Prior Disease Progression on H Based Therapy: Safety and Pharmacodynamic (PD) Results

Background: Preclinical data shows upregulation of the PI3K/AKT pathway and synergistic cytotoxicty between H+R in sensitive and resistant HER-2 overexpressing BC cell lines.

Methods: We designed a phase II clinical trial with an early stopping rule for excess toxicity in the first 4 wks of H+R therapy, defined as ≥3 cases of drug related grade 3 or 4 toxicity observed in the first 9 pts enrolled on trial. We report safety and PD results in 11 pts treated with oral R 6 mg daily + standard dosesand schedule of H. LVEF by ECHO or MUGA was assessed at baseline and every 3 months thereafter; treatment was held for LVEF drop below normal limits or ≥20 percentage points. Pre and post therapy tumor samples were collected when feasible. Circulating tumor (CTC) and endothelial (CEC) cells were collected and analyzed using the Veridex Cell Search System at baseline, wks 1, 2 and 4 and with every restaging.

Results: 11 pts with median age 56 y (range 38-70) treated with H+R were evaluable for safety. Median # cycles was 3 (range 1+ to 12). Non-hematologic grade 3 toxicities in first 4 wks occurred in 3 of the first 9 pts: 1 pt had syncope associated with leucopenia/neutropenia and urinary infection; 1pt had mucositis which responded to dose reduction; 1 pt with known diabetes had grade 3 hyperglycemia, however, this was non-fasting. One pt had grade 3 leucopenia/neutropenia which responded to dose reduction. Grade 3 toxicities for 11 pts in all cycles were as follows: leucopenia/neutropenia (2 pts), non-fasting hyperglycemia (2 pts), syncope (1 pt), hypokalemia (1pt), hyponatremia (1 pt), mucositis (1 pt), rash (2 pts), nail changes (1 pt), thrombosis (1 pt). Infection (urine in 1 pt, skin in 1 pt), anemia (1pt), and elevated PTT (1 pt). One grade 4 non-fasting hyperglycemia occurred in a diabetic pt. LVEF dropped below normal limits and recovered subsequently in 2 pts. Nine pts had baseline and at least one subsequent evaluation for radiographic response by RECIST. Best response was unconfirmed partial response (PR) in 1 pt (8 cycles), stable disease (SD) in 5 pts (12, 6+,6, 3, and 2 cycles) and progression (PD) in 3pts. We combined analysis of AKT pathway markers from 12 baseline and 9 post therapy tissue samples collected on this trial and a phase I study of R +chemotherapy. There were high correlations between baseline AKT pathway markers (mTOR, PTEN, Akt, pAkt, S6K1 and pS6K1; (Spearman's rho-0.401-0.907). This correlation was lost in post therapy samples. Higher mean mTOR levels were seen in non-responders (PD) vs. responders (SD/PR) [p value=0.04]. Eight pts had CTC and CEC results, and were evaluable for response. Baseline CTC levels of &gt;5 cells/7.5 ml were seen in 2/2 pts with PD and 0/6 pts with SD/PR. There was no significant difference in CEC levels between responders and non-responders. Conclusion: R 6 mg daily appears to be well tolerated when combined with standard doses of H. PR in 1 pt and SD for ≥6 months was observed in 2 pts with prior progression on H based therapy. Baseline elevated mTOR level correlates with poor response to R based combinations. Post therapy change in marker expression suggests biologic effect of R.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-14-17.

Adult Rat Odontoblasts Lack Noxious Thermal Sensitivity

Dentin hypersensitivity is a common symptom treated in the dental clinic, yet the underlying cellular and molecular mechanisms are not clear. We hypothesized that odontoblasts detect noxious thermal stimuli by expressing temperature-sensing molecules, and investigated whether temperature-activated TRP channels (thermo-TRP channels), which are known to initiate temperature signaling, mediate temperature sensing in odontoblasts. mRNA expression of dentin sialophosphoprotein and collagenase type 1, odontoblast-specific proteins, was shown in acutely isolated adult rat odontoblasts by single-cell RT-PCR, while TRPV1, TRPV2, TRPM8, and TRPA1 were not detected. Application of noxious temperatures of 42°C and 12°C, as well as capsaicin, menthol, and icilin, agonists of thermo-TRP channels, failed to increase intracellular calcium concentration. Immunohistochemical study also revealed no expression of TRPV1. Thus, it is unlikely that odontoblasts serve as thermal sensors in teeth via thermo-TRP channels.

Modulation of CaV2.3 calcium channel currents by eugenol

Eugenol, a natural congener of capsaicin, is a routine analgesic agent in dentistry. We have recently demonstrated the inhibition of Ca(V)2.2 calcium channel and sodium channel currents to be molecular mechanisms underlying the analgesic effect of eugenol. We hypothesized that Ca(V)2.3 channels are also modulated by eugenol and investigated its mode of action using the whole-cell patch-clamp technique in a heterologous expression system. Eugenol inhibited calcium currents in the E52 cell line, stably expressing the human Ca(V)2.3 calcium channels, where TRPV1 is not endogenously expressed. The extent of current inhibition was not significantly different between naïve E52 cells and TRPV1-expressing E52 cells, suggesting no involvement of TRPV1. In contrast, TRPV1 activation is prerequisite for the inhibition of Ca(V)2.3 calcium channels by capsaicin. The results indicate that eugenol has mechanisms distinct from those of capsaicin for modulating Ca(V)2.3 channels. We suggest that inhibition of Ca(V)2.3 channels by eugenol might contribute to its analgesic effect.

The Centre for Health Informatics at the University of New South Wales - a Clinical Informatics Research Centre

Building a sustainable health system in the 21st Century will require the reinvention of much of the present day system, and the intelligent use of information and communication technologies (ICT) to deliver high quality, safe, efficient and affordable health care. The Centre for Health Informatics (CHI) is Australia’s largest academic research group in this emerging discipline.

Our research is underpinned by a planning process, based on different future scenarios for the health system, which helps us identify longer-term problems needing a sustained research effort. A research competency matrix is used to ensure that the Centre has the requisite core capabilities in the research methods and tools needed to pursue our research program.

The Centre’s work is internationally recognized for its contributions in the development of intelligent search systems to support evidence-based healthcare, developing evaluation methodologies for ICT, and in understanding how communication shapes the safety and quality of health care delivery. Centre researchers also are working on safety models and standards for ICT in healthcare, mining complex gene micro array, medical literature and medical record data, building health system simulation methods to model the impact of health policy changes, and developing novel computational methods to automate the diagnosis of 3-D medical images.

Any individual research group like CHI must necessarily focus on a few areas to allow it to develop sufficient research capacity to make novel and internationally significant contributions. As CHI approaches the end of its first decade, it is becoming clear that developing capacity becomes increasingly challenging as the research territory changes under our feet, and that the Centre will continue to evolve and shift its focus in the years to come.

The Centre for Health Informatics at the University of New South Wales--a clinical informatics research centre

OBJECTIVES

Building a sustainable health system in the 21st Century will require the reinvention of much of the present day system, and the intelligent use of information and communication technologies (ICT) to deliver high quality, safe, efficient and affordable health care. The Centre for Health Informatics (CHI) is Australia's largest academic research group in this emerging discipline.

METHODS

Our research is underpinned by a planning process, based on different future scenarios for the health system, which helps us identify longer-term problems needing a sustained research effort. A research competency matrix is used to ensure that the Centre has the requisite core capabilities in the research methods and tools needed to pursue our research program.

RESULTS

The Centre's work is internationally recognized for its contributions in the development of intelligent search systems to support evidence-based healthcare, developing evaluation methodologies for ICT, and in understanding how communication shapes the safety and quality of health care delivery. Centre researchers also are working on safety models and standards for ICT in healthcare, mining complex gene micro array, medical literature and medical record data, building health system simulation methods to model the impact of health policy changes, and developing novel computational methods to automate the diagnosis of 3-D medical images.

CONCLUSIONS

Any individual research group like CHI must necessarily focus on a few areas to allow it to develop sufficient research capacity to make novel and internationally significant contributions. As CHI approaches the end of its first decade, it is becoming clear that developing capacity becomes increasingly challenging as the research territory changes under our feet, and that the Centre will continue to evolve and shift its focus in the years to come.

Neoadjuvant dose-dense (DD) concurrent doxorubicin (A) and docetaxel (T) for stage III breast cancer (BC)

10721

Background: The addition of taxanes to anthracycline therapy results in improved disease-free survival (DFS) in the adjuvant setting, and increased pathologic complete response rates (pCR) in the neoadjuvant setting. DD chemotherapy improves DFS and overall survival (OS). We evaluated neoadjuvant DD concurrent AT. Methods: Eligible patients (pts) with stage III BC were treated with AT q 14 days at 1 of 3 dose levels; L1 = 60 mg/m2 for both drugs (4 pts), L2 = A 75 mg/m2 and T 60 mg/m2 (6 pts) or L3 = 75 mg/m2 for both drugs (7 pts) × 6 cycles with G-CSF. Dexrazoxane was given after a cumulative dose of 300 mg/m2 of A. Pts were stratified to post-operative moderate risk (ModR) (≥ partial response, ≤ 3 lymph nodes (LN)) and received adjuvant IV cyclophosphamide (C) 600 mg/m2, methotrexate 40 mg/m2, 5FU 600 mg/m2 IV q 21 d × 6 (CMF), or high risk (HiR) (≤ minor response +/or ≥ 4 LN) and received C 3 gm/m2 q 14 d x 3. Primary endpoints were clinical and pathologic response rates of neoadjuvant AT. Sample size was 42 pts to estimate pCR and provide 90% confidence the true incidence of severe toxicity is <10%. Results: 17 pts with stage III BC were enrolled between 2/1999 and 7/2001; accrual was halted after data on pre-operative trastuzumab were presented. Median age was 50 yrs [range: 34–69]. 3/17 pts (17.6%) had a pCR, and 3 pts had near pCR (residual foci ≤ 1mm), 4/17 (23.5%) had path (-) LN, 7/17 (41%) had a lumpectomy, 7/17 (41%) required dose reductions of AT due to grade 4 neutropenia (5 pts) and grade 3 neuropathy (2 pts). 3 pts required treatment cessation; 1 pt (L2) for prolonged neutropenic fever and 2 pts (L3) for decreased ejection fraction and for acute renal failure. 15 pts were ModR and received adjuvant CMF, 1/2 pts stratified to high dose C declined it and received CMF. Median follow-up is 63 months [range: 28–80] with 13/17 (76.5%) pts surviving, and 12/17 (70.5%) pts surviving and free of disease. Conclusion: Neoadjuvant DD AT every 2 weeks is well-tolerated, with promising activity and survival in locally advanced BC.

[Table: see text]