Nitric oxide synthase phosphorylation in fetoplacental endothelium is enhanced by agonism of Piezo1 mechanosensor in small for gestational age babies

Lay summary

Friction caused by blood flowing across cells that line blood vessels (endothelial cells) activates sensors of mechanical force. This produces nitric oxide (NO) which widens placental blood vessels, enabling more blood flow to the baby. This study sought to determine whether the mechanical sensor, Piezo1, is important for NO production in fetoplacental endothelial cells (FpECs) and whether the steps in this pathway are different in small for gestational age (SGA) babies, where placental blood flow is often altered. We showed that in healthy FpECs, blood flow increased NO signalling. We suggest that in SGA babies, FpECs have an increase in baseline levels of NO signalling, suggestive of a compensatory drive. Treating healthy and SGA cells with a Piezo1 chemical activator, Yoda1, upregulated NO signalling. This shows that Piezo1 is linked to NO and that in SGA, FpECs have the capacity to further increase NO. Further research will establish whether Piezo1 enhancement leads to increased blood flow in the placenta. If so, Piezo1 could be a new target for developing treatments to prevent poor growth of babies in the womb.

Abstract LB173: AACR President's initiative - 2020 by 2020: Democratizing precision cancer medicine and advancing health equity in the black belt

African Americans (AA) have higher incidence and mortality rates for several cancer types in comparison to their European American (EA) counterparts. Increasing participation in clinical research and patient registries, related to precision cancer medicine, will significantly improve cancer health equity. Many AA cancer patients are treated in community oncology clinics. Unfortunately, these health systems have limited access to Clinical Laboratory Improvement Amendments (CLIA) next generation sequence (NGS) germline and somatic DNA and RNA testing that are used to inform oncologists on the best treatment and/or clinical trial options for cancer patients. Indeed, AA CLIA NGS sample sets are poorly represented, which could presumably result in incomplete knowledge of genomic variants that could affect their treatment and overall outcomes. Hence, it is crucial to implement CLIA NGS efforts for all cancer patients. To address these disparities, Morehouse School of Medicine has formed the Comprehensive Approach to Reimagine health Equity Solutions (CARhES) consortium with Tuskegee University that has engaged community oncology practices in Alabama and Georgia - two of five Black Belt states. The CARhES consortium aims to implement precision cancer medicine to underserved and underrepresented communities that will improve the standard of cancer care by providing access to CLIA NGS testing, clinical trials, and personalized cancer care. Here we describe the first proof of concept of this approach with community oncology partners, i.e., Grady Health System, Wellstar Health System, Georgia Urology, Midtown Urology, and Maui Memorial Medical Center. At the time of consent, saliva, buccal, and tumor samples were collected from participants. Germline and somatic CLIA NGS was performed, and medical reports were returned to practitioners within 14 days. Prior to the COVID pandemic, the study enrolled over 880 patients with a 88% consent rate (n = 1000) in the first 11months of the program. At the start of the COVID pandemic, recruitment efforts were suspended for four months with a slow restart by June 2020. A decrease in the number of staff, office visits (67% reduction), and increase in COVID cases significantly limited recruitment efforts. During this slowdown, we established and improved eConsenting capabilities, which exist today. Community anxiety, due to the pandemic and SARS-CoV-19 vaccine efforts, resulted in a significant reduction in consent rates (88% to 60%). Nevertheless, this study began in April of 2019 and consented 1,750 participants in less than 2 years. Taken together, our study shows that a community-focused precision medicine approach requires meeting people where they are and providing them with access and understanding the benefit of clinical trial participation. The approximate 2,000 clinically annotated genomic AA datasets will greatly contribute to our understanding of cancer health disparities and among the first steps to democratize precision medicine.

This study was funded by the American Association for Cancer Research, The Pelotonia Foundation, the M2Gen Foundation, and the National Cancer Institute (U54CA118638).

Citation Format: Latrisha L. Horne, Gabriella M. Oprea-Ilies, Eddie R. Stanley, Carla M. Holloway, Margaret P. Hooker, Amina Isom, Derrick J. Beech, Ana Gaonkar, Shavette Harden, Jeffrey F. Hines, LaTonya Randolph, James K. Bennett, Daniel Canter, Darrell J. Carmen, Pooja Mishra, Giuseppe Del Priore, Roland Matthews, Brian M. Rivers, James W. Lillard. AACR President's initiative - 2020 by 2020: Democratizing precision cancer medicine and advancing health equity in the black belt [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB173.

Emerging concepts of shear stress in placental development and function

Blood flow, and the force it generates, is critical to placental development and function throughout pregnancy. This mechanical stimulation of cells by the friction generated from flow is called shear stress (SS) and is a fundamental determinant of vascular homeostasis, regulating remodelling and vasomotor tone. This review describes how SS is fundamental to the establishment and regulation of the blood flow through the uteroplacental and fetoplacental circulations. Amongst the most recent findings is that alongside the endothelium, embryonic stem cells and the villous trophoblast are mechanically sensitive. A complex balance of forces is required to enable effective establishment of the uteroplacental circulation, while protecting the embryo and placental villi. SS also generates flow-mediated vasodilatation through the release of endothelial nitric oxide, a process vital for adequate placental blood flow. The identification of SS sensors and the mechanisms governing how the force is converted into biochemical signals is a fast-paced area of research, with multiple cellular components under investigation. For example, the Piezo1 ion channel is mechanosensitive in a variety of tissues including the fetoplacental endothelium. Enhanced Piezo1 activity has been demonstrated in response to the Yoda1 agonist molecule, suggesting the possibility for developing tools to manipulate these channels. Whether such agents might progress to novel therapeutics to improve blood flow through the placenta requires further consideration and research.

Piezo1 channels are mechanosensors in human fetoplacental endothelial cells

STUDY QUESTION

Does the shear stress sensing ion channel subunit Piezo1 have an important mechanotransduction role in human fetoplacental endothelium?

SUMMARY ANSWER

Piezo1 is present and functionally active in human fetoplacental endothelial cells, and disruption of Piezo1 prevents the normal response to shear stress.

WHAT IS KNOWN ALREADY

Shear stress is an important stimulus for maturation and function of placental vasculature but the molecular mechanisms by which the force is detected and transduced are unclear. Piezo1 channels are Ca²⁺-permeable non-selective cationic channels which are critical for shear stress sensing and maturation of murine embryonic vasculature.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We investigated the relevance of Piezo1 to placental vasculature by studying human fetoplacental endothelial cells (FpECs) from healthy pregnancies. Endothelial cells were isolated from placental cotyledons and cultured, for the study of tube formation and cell alignment to shear stress. In addition, human placental arterial endothelial cells were isolated and studied immediately by patch-clamp electrophysiology.

MAIN RESULTS AND THE ROLE OF CHANCE

The synthetic Piezo1 channel agonist Yoda1 caused strong elevation of the intracellular Ca²⁺ concentration with a 50% effect occurring at about 5.4 μM. Knockdown of Piezo1 by RNA interference suppressed the Yoda1 response, consistent with it being mediated by Piezo1 channels. Alignment of cells to the direction of shear stress was also suppressed by Piezo1 knockdown without loss of cell viability. Patch-clamp recordings from freshly isolated endothelium showed shear stress-activated single channels which were characteristic of Piezo1.

LIMITATIONS, REASONS FOR CAUTION

The in vitro nature of fetoplacental endothelial cell isolation and subsequent culture may affect FpEC characteristics and PIEZO1 expression. In addition to Piezo1, alternative shear stress sensing mechanisms have been suggested in other systems and might also contribute in the placenta.

WIDER IMPLICATIONS OF THE FINDINGS

These data suggest that Piezo1 is an important molecular determinant of blood flow sensitivity in the placenta. Establishing and manipulating the molecular mechanisms regulating shear stress sensing could lead to novel therapeutic strategies to improve blood flow in the placenta.

LARGE-SCALE DATA

Not applicable.

STUDY FUNDING/COMPETING INTEREST(S)

LCM was funded by a Clinical Research Training Fellowship from the Medical Research Council and by the Royal College of Obstetricians and Gynaecologists, and has received support from a Wellcome Trust Institutional Strategic Support Fund. JS was supported by the Wellcome Trust and a BHF Intermediate Research Fellowship. HJG, CW, AJH and PJW were supported by PhD Studentships from BHF, BBSRC and the Leeds Teaching Hospitals Charitable Foundation respectively. All authors declare no conflict of interest.

Leptin-Notch signaling axis is involved in pancreatic cancer progression

Pancreatic cancer (PC) shows a high death rate. PC incidence and prognosis are affected by obesity, a pandemic characterized by high levels of leptin. Notch is upregulated by leptin in breast cancer. Thus, leptin and Notch crosstalk could influence PC progression. Here we investigated in PC cell lines (BxPC-3, MiaPaCa-2, Panc-1, AsPC-1), derived tumorspheres and xenografts whether a functional leptin-Notch axis affects PC progression and expansion of pancreatic cancer stem cells (PCSC). PC cells and tumorspheres were treated with leptin and inhibitors of Notch (gamma-secretase inhibitor, DAPT) and leptin (iron oxide nanoparticle-leptin peptide receptor antagonist 2, IONP-LPrA2). Leptin treatment increased cell cycle progression and proliferation, and the expression of Notch receptors, ligands and targeted molecules (Notch1-4, DLL4, JAG1, Survivin and Hey2), PCSC markers (CD24/CD44/ESA, ALDH, CD133, Oct-4), ABCB1 protein, as well as tumorsphere formation. Leptin-induced effects on PC and tumorspheres were decreased by IONP-LPrA2 and DAPT. PC cells secreted leptin and expressed the leptin receptor, OB-R, which indicates a leptin autocrine/paracrine signaling loop could also affect tumor progression. IONP-LPrA2 treatment delayed the onset of MiaPaCa-2 xenografts, and decreased tumor growth and the expression of proliferation and PCSC markers. Present data suggest that leptin-Notch axis is involved in PC. PC has no targeted therapy and is mainly treated with chemotherapy, whose efficiency could be decreased by leptin and Notch activities. Thus, the leptin-Notch axis could be a novel therapeutic target, particularly for obese PC patients.

Piezo1 Channels in Vascular Development and the Sensing of Shear Stress

A critical point in mammalian development occurs before mid-embryogenesis when the heart starts to beat, pushing blood into the nascent endothelial lattice. This pushing force is a signal, detected by endothelial cells as a frictional force (shear stress) to trigger cellular changes that underlie the essential processes of vascular remodeling and expansion required for embryonic growth. The processes are complex and multifactorial and Piezo1 became a recognized player only 2years ago, 4years after Piezo1's initial discovery as a functional membrane protein. Piezo1 is now known to be critical in murine embryonic development just at the time when the pushing force is first detected by endothelial cells. Murine Piezo1 gene disruption in endothelial cells is embryonic lethal and mutations in human PIEZO1 associate with severe disease phenotype due to abnormal lymphatic vascular development. Piezo1 proteins coassemble to form calcium-permeable nonselective cationic channels, most likely as trimers. They are large proteins with little if any resemblance to other proteins or ion channel subunits. The channels appear to sense mechanical force directly, including the force imposed on endothelial cells by physiological shear stress. Here, we review current knowledge of Piezo1 in the vascular setting and discuss hypotheses about how it might serve its vascular functions and integrate with other mechanisms. Piezo1 is a new important player for investigators in this field and promises much as a basis for better understanding of vascular physiology and pathophysiology and perhaps also discovery of new therapies.

Abstract 1034: Leptin induces early onset and aggressiveness of pancreatic cancer

Background: During the past 30 years, pancreatic cancer (PC) has constantly been the fourth leading cause of cancer death. PC is usually advanced at the time of diagnosis, with an overall five years survival rate of less than 5%. Obesity, characterized by high levels of leptin, is pandemic in United States and a risk factor for PC. Notch abnormal signaling is linked to carcinogenesis, tumor angiogenesis and self renewal capacity of PC stem cells (PCSC). We have previously shown that leptin induces proliferation of PC cell lines, increases Notch expression, PCSC and tumorsphere formation. To test leptin effects in a PC mouse model, a specific and potent signaling inhibitor bound to nanoparticles, IONP-LPrA2 was produced by us.

Hypothesis: High levels of leptin induce early onset and multiplicity of PC xenografts, which is abrogated by IONP-LPrA2 treatment.

Methods: Human PC cell line MiaPaCa-2 was challenged with leptin or IONP-LPrA2. The expression of pluripotency associated genes (STAT3, Oct4, Sox2 and NANOG) was evaluated. MiaPaCa-2 cells forming tumorspheres were treated with leptin or IONP-LPrA2 and inoculated into CD1 nu/nu mice. Untreated tumorspheres were inoculated as controls. A group of mice were injected twice a week with IONP-LPrA2. Tumor onset and growth were assessed. PC xenografts were analyzed for expression of Ki67 (proliferation marker), leptin targeted molecules (Notch), PCSC markers etc.

Results: Leptin induced the expression of PCSC pluripotency markers. Moreover, leptin treatment of tumorspheres induced early tumor onset and multiplicity. Also, leptin increased proliferation, PCSC and oncogenic markers in PC xenografts. IONP-LPrA2 reduced leptin effects. No changes of mice food intake and body weight were observed.

Conclusions: This observation might imply that obese patients are at high risk to develop PC. Inhibition of leptin signaling may be used as preventative or therapeutic strategy for PC, especially in obese patients.

Acknowledgements: this work was supported by DOD W81XWH-13-1-0382; NIH/SBIR 1R41CA183399-01A1; Pilot Project Award from MSM/Tuskegee University/UAB Cancer Center partnership grant 5U54CA118638; PC SPORE Grant from UAB to RRGP, and facilities and support services at Morehouse School of Medicine (1G12RR026250-03; NIH RR 03034 and 1C06 RR18386).

Citation Format: Adriana Harbuzariu, Antonio Rampoldi, Danielle S. Daley-Brown, Tia L. Harmon, Derrick J. Beech, Gabriela Oprea-Ilies, Ruben R. Gonzalez-Perez. Leptin induces early onset and aggressiveness of pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1034.

Abstract 1701: CCR6 associates with colon cancer metastasis

Despite established benefits of screening, colon cancer remains a leading cause of cancer death in the U.S. Majority of colon cancer deaths result from metastasis. Effective treatments are not available for advanced disease because molecular mechanisms of initiation and progression of this disease are yet to be defined. Chemokine-chemokine receptor interaction plays an important role in cancer progression. In this study, using colon cancer tissue microarray, we have shown that expression of CCR6 was significantly higher in advanced colon cancer (p<0.0001) with distant and regional lymph node metastasis as compared to non-metastatic and adjacent normal tissues. Expression of CCR6 was further confirmed in cell lines derived from Dukes's type C and type D colon cancer patients using flow cytometric analysis. Like tissues, CCR6 expression was significantly (p<0.0001) higher in colon cancer cell lines compared to normal colon epithelial cells. Furthermore, colon cancer cells showed higher migratory potential toward chemotactic gradient of its only known natural ligand, CCL20. Cell proliferation was also inhibited in presence of CCL20. Significant decrease in E-cadherin, increased expression of vimentin, β-catenin, N-cadherin, α-SMA, SNAIL and ZEB1 was observed following CCL20 treatment. These results suggest the importance of CCR6-CCL20 axis in the etiopathogenesis of colon cancer and highlight its potential as therapeutic target.

Citation Format: Neeraj Kapur, Hina Mir, Clarence E. Clark, Uma Krishnamurti, Derrick J. Beech, James W. Lillard, Shailesh Singh. CCR6 associates with colon cancer metastasis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1701.

Molecular Mechanism Linking BRCA1 Dysfunction to High Grade Serous Epithelial Ovarian Cancers with Peritoneal Permeability and Ascites

Ovarian cancer constitutes the second most common gynecological cancer with a five-year survival rate of 40%. Among the various histotypes associated with hereditary ovarian cancer, high-grade serous epithelial ovarian carcinoma (HGSEOC) is the most predominant and women with inherited mutations in BRCA1 have a lifetime risk of 40-60%. HGSEOC is a challenge for clinical oncologists, due to late presentation of patient, diagnosis and high rate of relapse. Ovarian tumors have a wide range of clinical presentations including development of ascites as a result of deregulated endothelial function thereby causing increased vascular permeability of peritoneal vessels. The molecular mechanisms remain elusive. Studies have shown that fallopian tube cancers develop in women with BRCA1 gene mutations more often than previously suspected. Recent studies suggest that many primary peritoneal cancers and some high-grade serous epithelial ovarian carcinomas actually start in the fallopian tubes. In this article we have addressed the molecular pathway of a recently identified potential biomarker Ubc9 whose deregulated expression due to BRCA1 dysfunction can result in HGSEOC with peritoneal permeability and formation of ascites. We also discuss the role of downstream targets Caveolin-1 and Vascular Endothelial Growth Factor (VEGF) in the pathogenesis of ascites in ovarian carcinomas. Finally we hypothesize a signaling axis between Ubc9 over expression, loss of Caveolin-1 and induction of VEGF in BRCA1 mutant HGSEOC cells. We suggest that Ubc9-mediated stimulation of VEGF as a novel mechanism underlying ovarian cancer aggressiveness and ascites formation. Agents that target Ubc9 and VEGF signaling may represent a novel therapeutic strategy to impede peritoneal growth and spread of HGSEOC.

Situs inversus

Situs Inversus is a rare condition with unique clinical and radiographic characteristics. We present a case highlighting important clinical factors associated with Situs Inversus.

Subungual melanoma: diagnosis and management

Subungual Melanoma accounts for less than three percent of all cutaneous melanomas and has a dismal prognosis. Our case report outlines the current approach for diagnosis and management of this rare form of acral lentiginous melanoma.

Triple Negative Breast Cancer - An Overview

Triple Negative Breast Cancer (TNBC) is a heterogeneous disease that based on immunohistochemistry (IHC) is estrogen receptor (ER) negative, progesterone receptor (PR) negative and human epidermal growth factor receptor 2 (HER2) negative. TNBC is typically observed in young AA women and Hispanic women who carry a mutation in the BRCA1 gene. TNBC is characterized by a distinct molecular profile, aggressive nature and lack of targeted therapies. The purpose of this article is to review the current and future novel signalling pathways as therapeutic approaches to TNBC. Recent Identification of a new BRCA1 trafficking pathway holds promise in the future for the development of targeted therapies for TNBC.

Properties and therapeutic potential of transient receptor potential channels with putative roles in adversity: focus on TRPC5, TRPM2 and TRPA1

Mammals contain 28 genes encoding Transient Receptor Potential (TRP) proteins. The proteins assemble into cationic channels, often with calcium permeability. Important roles in physiology and disease have emerged and so there is interest in whether the channels might be suitable therapeutic drug targets. Here we review selected members of three subfamilies of mammalian TRP channel (TRPC5, TRPM2 and TRPA1) that show relevance to sensing of adversity by cells and biological systems. Summarized are the cellular and tissue distributions, general properties, endogenous modulators, protein partners, cellular and tissue functions, therapeutic potential, and pharmacology. TRPC5 is stimulated by receptor agonists and other factors that include lipids and metal ions; it heteromultimerises with other TRPC proteins and is involved in cell movement and anxiety control. TRPM2 is activated by hydrogen peroxide; it is implicated in stress-related inflammatory, vascular and neurodegenerative conditions. TRPA1 is stimulated by a wide range of irritants including mustard oil and nicotine but also, controversially, noxious cold and mechanical pressure; it is implicated in pain and inflammatory responses, including in the airways. The channels have in common that they show polymodal stimulation, have activities that are enhanced by redox factors, are permeable to calcium, and are facilitated by elevations of intracellular calcium. Developing inhibitors of the channels could lead to new agents for a variety of conditions: for example, suppressing unwanted tissue remodeling, inflammation, pain and anxiety, and addressing problems relating to asthma and stroke.

Abstract A45: Molecular targets in early detection and differentiation of inflammatory bowel disease-associated colon-rectal-anal cancer disparities

The inflammatory bowel disease (IBD), Crohn's (CC) and ulcerative colitis (UC), affect approximately 1–2 of every 1000 people in developed countries. These chronic inflammatory diseases result in significant morbidity and mortality. All IBD-associated colorectal-anal cancers (CRAC) occurred in segments of colitis and are frequently diagnosed at an advanced stage. This presentation is a continuation of our work that investigates potential molecules that could define a unique classifier between CC and UC and early detection of CRAC.

There are multiple challenges to identifying protein classifiers suggesting outcome prediction and differentiation for patients with IBD and/or IBD-CRAC from molecular interpretation standpoints is complex. While there are technical approach advances, the goal is clear however: to produce scientific evidence which can provide personalized expert care to patients.

We have developed an amenable proteomic methodology that supports the diagnostic feasibility to discriminate molecularly, different inflammatory colitis. The histologic layers of colectomy samples from patients with confirmed UC and CC tissues were analyzed using matrix-assisted laser de-sorption/ionization mass spectrometry (MALDI MS) for proteomic profiling.

Our previous findings (1) prompted further sample collection resulting in an increased sample size that would allow a more robust analysis. The samples from colon tissues collected in 2008 and samples collected in 2010 were re-randomized into training and independent test sets in order to avoid systematic differences between new and old data sets, typical for MALD-ToF spectra acquired in situ from tissue at different times. MALDI-ToF spectra were included in the analysis only for samples containing more than 3 unique spectra. Our studies have successfully identified 11 highly significant mass-to-charge ratio (m/z) signals (m/z 5045, 6139, 9245, 8413, 3666, 3595, 4122, 8774, 2778, 9232 and 9519) that distinguish CC from UC. These features are independent of the tissue of origin and represent disease specific markers. Some of these signatures were only found in the colonic mucosa (m/z 8413, 3666 & 3595) or submucosa (m/z 4122, 8774, 2778, 9232 & 9519) while others were found in both two layers (m/z 5045, 6139 & 9245). This information may provide new avenues for the development of novel diagnostic, prognostic and therapeutic targets. We will analyze CRAC in IBD segments2,3 to look for these proteins that may help in studying their biological mechanisms in cancer transformation.

Support: 3U54CA091408-09S1 (to MMC-VICC Partnership: SE Adunyah & HL Moses)

References:

1. M'Koma AE, Seely EH, Washington MK, Schwartz DA, Muldoon RL, Herline AJ, Wise PE, Caprioli RM Proteomic Profiling of Mucosal and Submucosal Colonic Tissues Yields Protein Signatures that Differentiate the Inflammatory Colitides. Inflamm Bowel Dis 2011;17:875-83.

2. M'Koma AE, Moses HL, Adunyah SE. Inflammatory bowel disease-associated colorectal cancer: proctocolectomy andmucosectomy does not necessarily eliminate pouch related cancer incidences. Int J colorect Dis 2011;26:533-52.

3. Um JW, M'Koma AE. Pouch-related dysplasia and adenocarcinoma following restorative proctocolectomy for ulcerative colitis. Tech coloproctol 2011;15:7-16.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):A45.

Stereo-selective inhibition of transient receptor potential TRPC5 cation channels by neuroactive steroids

BACKGROUND AND PURPOSE

Transient receptor potential canonical 5 (TRPC5) channels are widely expressed, including in the CNS, where they potentiate fear responses. They also contribute to other non-selective cation channels that are stimulated by G-protein-coupled receptor agonists and lipid and redox factors. Steroids are known to modulate fear and anxiety states, and we therefore investigated whether TRPC5 exhibited sensitivity to steroids.

EXPERIMENTAL APPROACH

Human TRPC5 channels were conditionally expressed in HEK293 cells and studied using intracellular Ca²⁺ measurement, whole-cell voltage-clamp and excised patch techniques. For comparison, control experiments were performed with cells lacking TRPC5 channels or expressing another TRP channel, TRPM2. Native TRPC channel activity was recorded from vascular smooth muscle cells.

KEY RESULTS

Extracellular application of pregnenolone sulphate, pregnanolone sulphate, pregnanolone, progesterone or dihydrotestosterone inhibited TRPC5 activity within 1–2 min. Dehydroepiandrosterone sulphate or 17β-oestradiol had weak inhibitory effects. Pregnenolone, and allopregnanolone, a progesterone metabolite and stereo-isomer of pregnanolone, all had no effects. Progesterone was the most potent of the steroids, especially against TRPC5 channel activity evoked by sphingosine-1-phosphate. In outside-out patch recordings, bath-applied progesterone and dihydrotestosterone had strong and reversible effects, suggesting relatively direct mechanisms of action. Progesterone inhibited native TRPC5-containing channel activity, evoked by oxidized phospholipid.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that TRPC5 channels are susceptible to relatively direct and rapid stereo-selective steroid modulation, leading to channel inhibition. The study adds to growing appreciation of TRP channels as non-genomic steroid sensors.

Primary Breast Lymphoma: A Rare Clinical Entity

Localized primary breast lymphoma is very rare. The typical clinical and radiographic presentation of isolated primary breast lymphoma mimics that of breast adenocarcinoma. Histologic diagnosis of primary breast lymphoma relies heavily on Hematoxylin and Eosin pathologic evaluation and immunohistochemical staining. Cytotoxic systemic chemotherapy is the primary treatment for this disease with the occasional need for adjuvant radiation therapy or surgical resection. This case report outlines the diagnosis and management of a patient with primary breast lymphoma.

Cis-isomerism and other chemical requirements of steroidal agonists and partial agonists acting at TRPM3 channels

BACKGROUND AND PURPOSE

The transient receptor potential melastatin-3 (TRPM3) channel forms calcium-permeable, non-selective, cationic channels that are stimulated by pregnenolone sulphate (PregS). Here, we aimed to define chemical requirements of this acute steroid action and potentially reveal novel stimulators with physiological relevance.

EXPERIMENTAL APPROACH

We used TRPM3 channels over-expressed in HEK 293 cells, with intracellular calcium measurement and whole-cell patch-clamp recording techniques.

KEY RESULTS

The stimulation of TRPM3 channels was confined to PregS and closely related steroids and not mimicked by other major classes of steroids, including progesterone. Relatively potent stimulation of TRPM3-dependent calcium entry was observed. A sulphate group positioned at ring A was important for strong stimulation but more striking was the requirement for a cis (beta) configuration of the side group, revealing previously unrecognized stereo-selectivity and supporting existence of a specific binding site. A cis-oriented side group on ring A was not the only feature necessary for high activity because loss of the double bond in ring B reduced potency and loss of the acetyl group at ring D reduced efficacy and potency. Weak steroid stimulators of TRPM3 channels inhibited effects of PregS, suggesting partial agonism. In silico screening of chemical libraries for non-steroid modulators of TRPM3 channels revealed the importance of the steroid backbone for stimulatory effects.

CONCLUSIONS AND IMPLICATIONS

Our data defined some of the chemical requirements for acute stimulation of TRPM3 channels by steroids, supporting the existence of a specific and unique steroid binding site. Epipregnanolone sulphate was identified as a novel TRPM3 channel stimulator.

Abstract A94: Multidisciplinary team approach improves breast cancer survival in minority women

Background: Approximately 192,370 women were diagnosed with breast cancer in the United States in 2009. This represents approximately 1 in 8 American women facing the challenge of Breast Cancer therapy in their lifetime. Further, more than 40,000 women will die of breast cancer annually. These statistics represent a significant improvement in the U.S. mortality rate for breast cancer. There continues to be a disparity in outcome from breast cancer with a significantly lower survival in African American women and the uninsured. Our multidisciplinary treatment team includes physicians, nurse navigator and clinical trials specialist are all focused on optimizing multimodal treatment, clinical trial participation, improved quality of life and survival.

Methods: All patients with invasive breast cancer diagnosed between 2004 and 2008 at our inner city, public safety-net hospital were included in this evaluation. Each patient had a confirmed histological diagnosis of breast adenocarcinoma. Patient demographic data, tumor staging, treatment and outcomes/survival were evaluated. Tumor Registry Data from our institution was compared to data from the National Cancer Database for the above mentioned time period. All patients at our hospital were treated by the same clinicians and staff utilizing a multidisciplinary team approach.

Results: There were 120 patients included in this study during the 5 year period. Of these, 4 patients were men. The majority of patients were between age 40 and 60. Our patients were significantly younger at initial diagnosis compared to the national findings. The ethnic distribution of our patient population: 54% African American, 41 % Caucasian, 3% Asian, 1 % American Indian, and 2% other. Evaluation of our payer status demonstrated that approximately 30% of our patients were self-pay and 32% indigent. Only 5% of our patients were insured with managed care organizations and less than 1% had private insurance.

Conclusion: Carefully coordinated multidisciplinary team management of patients with breast cancer resulted in improved clinical outcomes regardless of the patient's ethnicity or insurance status. Implementation of best practice protocols (coordinate multidisciplinary team management; nurse navigator and a vibrant clinical trials program) should become standard at all Community hospitals and academic medical centers, particularly medical facilities serving minority and uninsured patients.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A94.

Sigmoid-urachal-cutaneous fistula in an adult male

An infected urachal cyst is an uncommon finding in adults. We report the first case of a sigmoid-urachal-cutaneous fistula that resulted from rupture of an infected urachal cyst in an adult male. Definitive management consisted of resection of the urachus with a bladder cuff, along with removal of the affected bowel segments and bowel anastomosis.

Modulation of TRPC5 cation channels by halothane, chloroform and propofol

BACKGROUND AND PURPOSE

TRPC5 is a mammalian homologue of the Drosophila Transient Receptor Potential (TRP) channel and has expression and functions in the cardiovascular and nervous systems. It forms a calcium-permeable cation channel that can be activated by a variety of signals including carbachol (acting at muscarinic receptors), lanthanides (e.g. Gd3+) and phospholipids (e.g. lysophosphatidylcholine: LPC). Here we report the effects of inhalational (halothane and chloroform) and intravenous (propofol) general anaesthetics upon TRPC5.

EXPERIMENTAL APPROACH

Human TRPC5 channels were expressed in HEK 293 cells and studied using fura-2 and patch-clamp recording to measure intracellular calcium and membrane currents respectively at room temperature. Human TRPM2 channels were studied for comparison.

KEY RESULTS

TRPC5 activation by carbachol, Gd3+ or LPC was inhibited by halothane and chloroform at > or =0.1 and 0.2 mM respectively. Neither agent inhibited TRPM2. Propofol had an initial stimulatory effect on TRPC5 (evident in patch-clamp recordings only) and an inhibitory effect at > or =10 microM. TRPM2 was not affected by propofol. Propofol inhibited activation of TRPC5 by Gd3+ but not LPC, suggesting the effect was not directly on the channel. Propofol's anti-oxidant property was not necessary for its inhibitory effect because di-isopropyl benzene, a propofol analogue that lacks the hydroxyl group, also inhibited TRPC5.

CONCLUSIONS AND IMPLICATIONS

The data show the sensitivity of TRPC5 channel to general anaesthetics and suggest that some of the effects could have clinical relevance. The effects may be explained in part by the sensitivity of the channel to biophysical properties of the lipid bilayer.

Adenomatous hyperplasia of the gallbladder

Adenomatous hyperplasia of the gallbladder is an uncommon condition, particularly in men. A literature search yields minimal information on this entity, thus suggesting the infrequency of its occurrence. Adenomyomatosis is an entity that closely resembles adenomatous hyperplasia but has hypertrophy of the muscular layer and extensive Rokitansky-Aschoff sinuses. We report the finding of adenomatous hyperplasia in a middle-aged male in the setting of symptomatic cholelithiasis.

Bipolar phospholipid sensing by TRPC5 calcium channel

TRPC5 [TRP (transient receptor potential) canonical (or classical) 5] is a widely expressed mammalian homologue of Drosophila TRP, forming a calcium- and sodium-permeable channel in the plasma membrane either as a homomultimer or heteromultimer with other proteins (e.g. TRPC1). Although several factors are known to stimulate the channel, understanding of its endogenous activators and functions is limited. This paper provides a brief and focused review of our latest findings that show that TRPC5 is a sensor of important signalling phospholipids, including lysophosphatidylcholine and sphingosine 1-phosphate, acting extracellularly or intracellularly. Underlying mechanisms of action and biological relevance are discussed.

Laparoscopic revision of the gastrojejunostomy for recurrent bleeding ulcers after past open revision gastric bypass

Late complications of open gastric bypass can include malnutrition, weight gain, stomal stenosis, and recurrent bleeding ulcers. Herein, we describe the case of a woman who had recurrent bleeding ulcers, after an open revision of a stenotic gastric bypass. She now underwent an uneventful laparoscopic revision of her gastrojejunostomy and was discharged within 72 hours. Laparoscopic revision of a gastrojejunostomy, even after an open revision following an open gastric bypass, can be done safely.

Canonical transient receptor potential 5

Canonical transient receptor potential 5 TRPC5 (also TrpC5, trp-5 or trp5) is one of the seven mammalian TRPC proteins. Its known functional property is that of a mixed cationic plasma membrane channel with calcium permeability. It is active alone or as a heteromultimeric assembly with TRPC1; TRPC4 and TRPC3 may also be involved. Multiple activators of TRPC5 are emerging, including various G protein-coupled receptor agonists, lysophospholipids, lanthanide ions and, in some contexts, calcium store depletion. Intracellular calcium has complex impact on TRPC5, including a permissive role for other activators, as well as inhibition at high concentrations. Protein kinase C is inhibitory and mediates desensitisation following receptor activation. Tonic TRPC5 activity is detected and may reflect the presence of constitutive activation signals. The channel has voltage dependence but the biological significance of this is unknown; it is partially due to intracellular magnesium blockade at aspartic acid residue 633. Protein partners include calmodulin, CaBP1, enkurin, Na(+)-H+ exchange regulatory factor (NHERF) and stathmin. TRPC5 is included in local vesicular trafficking regulated by growth factors through phosphatidylinositol (PI)-3-kinase, Rac1 and PIP-5-kinase. Inhibition of myosin light chain kinase suppresses TRPC5, possibly via an effect on trafficking. Biological roles of TRPC5 are emerging but more reports on this aspect are needed. One proposed role is as a mediator of calcium entry and excitation in smooth muscle, another as an inhibitor of neuronal growth cone extension. The latter is intriguing in view of the original cloning of the human TRPC5 gene from a region of the X chromosome linked to mental retardation. TRPC5 is a broadly expressed calcium channel with capability to act as an integrator of extracellular and intracellular signals at the level of calcium entry.

Ageism in breast cancer surgical options by medical students

INTRODUCTION

The similar long-term survival of breast conservation and modified radical mastectomy in treating early invasive breast cancer has been well established. Since doctors often find themselves in the position of making operative recommendations, characterization of factors that may influence their recommendations is important. Previous investigations have demonstrated the phenomenon of ageism (i.e., between patients aged 30 versus 60 years old) in doctors and doctors-in-training. Thus, this study was undertaken to investigate any possible economic bias of doctors-in-training in breast conserving procedures.

METHODS

Medical students were instructed on the efficacy of breast conservation in treating breast cancer. Then, their opinions were assessed using a questionnaire about recommendations for breast conservation as well as breast reconstruction after mastectomies in similar patients. All patients were between the ages of 41-54 years old but differed by occupation. Chi squared tests were used for statistical analysis.

RESULTS

Forty-eight students participated in the study. No differences were noted between "high income" occupations and "low income" occupations. However, subtle ageism was noted even in this similarly aged population. Modified radical mastectomy was recommended in 35 percent of the "older" age group (41-48 years old) versus 15 percent of "younger" patients (49-54 years old, p < 0.002). Further, breast reconstruction was recommended in 89 percent of younger patients versus only 72 percent of older patients (p < 0.004).

CONCLUSIONS

Medical students still demonstrate an age bias against older women in their recommendations of breast conservation and breast reconstruction. Educational efforts should be instituted during the medical school training to decrease this age bias in treatment of breast cancer.

Paget's Disease of the Breast Areola Mimicking Cutaneous Melanoma

Paget's disease of the breast nipple and areola complex represents a cutaneous manifestation of an underlying breast malignancy. The typical skin changes characteristic of breast Paget's disease are usually easily distinguished from those found of malignant melanoma. The rare finding of a pigmented cutaneous breast lesion mimicking melanoma presents a diagnostic dilemma. This case presentation describes a pigmented mammary lesion involving the areola that had undergone changes in diameter and pigmentation. The lesion was not associated with nipple drainage, nipple excoriation, dermal ulceration, or a palpable breast mass. The areola lesion was highly suggestive of a dermatologic malignancy such as malignant melanoma. As such, a biopsy was performed with initial findings suggestive of cutaneous melanoma. Upon more detailed analysis of a larger excision specimen, immunohistochemical staining was highly supportive of the diagnosis of breast Paget's disease. A total mastectomy with sentinel lymph node evaluation was performed along with immediate reconstruction. The final pathology revealed a small focus of ductal carcinoma in situ of the breast associated with the areola changes. Histologic and immunohistochemical analysis of a biopsy specimen were paramount in differentiating these two lesions.

Upregulated TRPC1 channel in vascular injury in vivo and its role in human neointimal hyperplasia

Occlusive vascular disease is a widespread abnormality leading to lethal or debilitating outcomes such as myocardial infarction and stroke. It is part of atherosclerosis and is evoked by clinical procedures including angioplasty and grafting of saphenous vein in bypass surgery. A causative factor is the switch in smooth muscle cells to an invasive and proliferative mode, leading to neointimal hyperplasia. Here we reveal the importance to this process of TRPC1, a homolog of Drosophila transient receptor potential. Using 2 different in vivo models of vascular injury in rodents we show hyperplasic smooth muscle cells have upregulated TRPC1 associated with enhanced calcium entry and cell cycle activity. Neointimal smooth muscle cells after balloon angioplasty of pig coronary artery also express TRPC1. Furthermore, human vein samples obtained during coronary artery bypass graft surgery commonly exhibit an intimal structure containing smooth muscle cells that expressed more TRPC1 than the medial layer cells. Veins were organ cultured to allow growth of neointimal smooth muscle cells over a 2-week period. To explore the functional relevance of TRPC1, we used a specific E3-targeted antibody to TRPC1 and chemical blocker 2-aminoethoxydiphenyl borate. Both agents significantly reduced neointimal growth in human vein, as well as calcium entry and proliferation of smooth muscle cells in culture. The data suggest upregulated TRPC1 is a general feature of smooth muscle cells in occlusive vascular disease and that TRPC1 inhibitors have potential as protective agents against human vascular failure.

Poor knowledge of basic cancer facts of physicians-in-training

PURPOSE

Since many physicians-in-training will play an important role in cancer screening, their understanding of cancer screening and basic cancer facts is paramount. This investigation was undertaken to determine their baseline knowledge in basic cancer facts.

METHOD

A questionnaire was used to assess the knowledge of basic cancer facts of medical students, medical residents and surgical residents. Participants were asked to rank five different malignancies in their correct order for both mortality and incidence. Physicians-in-training were given separate questions for male and female patients. The questions were considered correct if at least the first three malignancies were ranked in the appropriate order.

RESULTS

One-hundred-twelve second-year medical students and 78 residents were assessed. Few physicians-in-training ranked the malignancies in correct order for mortality (21% for female patients and 18% for male patients). Even fewer physicians-in-training ranked the malignancies in correct order for incidence (2% for female patients and 9% for male patients).

CONCLUSION

Most physicians-in-training lack an understanding of basic cancer facts. If this poor basic cancer fact knowledge represents an overall lack of cancer knowledge, educational efforts need to be focused on cancer care for all levels and specialties of physician training.

Multivariate analysis of factors associated with smoking cessation in women

BACKGROUND

Appropriate smoking cessation techniques, including counseling patients to stop smoking, could prevent multiple health-related problems. Identification of relevant factors in patients that smoke may be beneficial in targeting smoking cessation efforts. This investigation explores various factors associated with smoking cessation, specifically in women.

METHODS

All women (n = 675) presenting to a breast health center over a one year period were surveyed regarding their tobacco use. Any association between smoking cessation and various factors was determined by multivariate analysis.

RESULTS

Our population consisted of 47% African American women, 43% Caucasian women, and 10% women of other ethnicities. Sixty percent of all women never smoked. Of the women who had smoked, 57% quit. Except for alcohol use and exercise, no factor, including ethnicity, was associated with never smoking. Smoking cessation was associated with being married, being Caucasian, not using alcohol, and exercising. However, only Caucasian race and marriage were independently associated with smoking cessation.

DISCUSSION

In our population, African American women had a lower proportion of smoking cessation than Caucasian women. In patients with similar access to care, specifically preventive care, there are ethnic and social differences in smoking cessation.

Non-selective cationic channels of smooth muscle and the mammalian homologues of Drosophila TRP

Throughout the body there are smooth muscle cells controlling a myriad of tubes and reservoirs. The cells show enormous diversity and complexity compounded by a plasticity that is critical in physiology and disease. Over the past quarter of a century we have seen that smooth muscle cells contain--as part of a gamut of ion-handling mechanisms--a family of cationic channels with significant permeability to calcium, potassium and sodium. Several of these channels are sensors of calcium store depletion, G-protein-coupled receptor activation, membrane stretch, intracellular Ca2+, pH, phospholipid signals and other factors. Progress in understanding the channels has, however, been hampered by a paucity of specific pharmacological agents and difficulty in identifying the underlying genes. In this review we summarize current knowledge of these smooth muscle cationic channels and evaluate the hypothesis that the underlying genes are homologues of Drosophila TRP (transient receptor potential). Direct evidence exists for roles of TRPC1, TRPC4/5, TRPC6, TRPV2, TRPP1 and TRPP2, and more are likely to be added soon. Some of these TRP proteins respond to a multiplicity of activation signals--promiscuity of gating that could enable a variety of context-dependent functions. We would seem to be witnessing the first phase of the molecular delineation of these cationic channels, something that should prove a leap forward for strategies aimed at developing new selective pharmacological agents and understanding the activation mechanisms and functions of these channels in physiological systems.

Dermatofibrosarcoma Protuberans and Breast Cancer: Genetic Link or Coincidental Association?

Dermatofibrosarcoma protuberans is a low-grade cutaneous neoplasm originating from the dermis with a high propensity for local recurrence. These malignancies are classified as soft tissue sarcoma although regional or distance metastatic spread is rare. Germ-line mutations of p53 have been described with a rare autosomal dominant syndrome in patients with soft tissue sarcoma and breast adenocarcinoma (Li Fraumeni's syndrome). The described case illustrates the rare occurrence of dermatofibrosarcoma protuberans (DFSP) and breast adenocarcinoma with an emphasis on the possibility of a molecular or genetic association.

Dermatofibrosarcoma protuberans and breast cancer: genetic link or coincidental association?

Dermatofibrosarcoma protuberans is a low-grade cutaneous neoplasm originating from the dermis with a high propensity for local recurrence. These malignancies are classified as soft tissue sarcoma although regional or distance metastatic spread is rare. Germ-line mutations of p53 have been described with a rare autosomal dominant syndrome in patients with soft tissue sarcoma and breast adenocarcinoma (Li Fraumeni's syndrome). The described case illustrates the rare occurrence of dermatofibrosarcoma protuberans (DFSP) and breast adenocarcinoma with an emphasis on the possibility of a molecular or genetic association.

Nodular Melanoma of the Face: A Rare Finding in African Americans

The incidence of melanoma has dramatically increased during the past several decades in the United States. Although the majority of cutaneous melanomas occur in Caucasians, African Americans are also susceptible to this malignancy. Cutaneous melanomas in African Americans typically occur on palms of the hands or soles of the feet. This report documents the rare occurrence of a nodular melanoma of the face in a dark-complexion African-American patient.

Nodular melanoma of the face: a rare finding in African Americans

The incidence of melanoma has dramatically increased during the past several decades in the United States. Although the majority of cutaneous melanomas occur in Caucasians, African Americans are also susceptible to this malignancy. Cutaneous melanomas in African Americans typically occur on palms of the hands or soles of the feet. This report documents the rare occurrence of a nodular melanoma of the face in a dark-complexion African-American patient.

Functional up-regulation of KCNA gene family expression in murine mesenteric resistance artery smooth muscle

This study focused on the hypothesis that KCNA genes (which encode K(V)alpha1 voltage-gated K(+) channels) have enhanced functional expression in smooth muscle cells of a primary determinant of peripheral resistance - the small mesenteric artery. Real-time PCR methodology was developed to measure cell type-specific in situ gene expression. Profiles were determined for arterial myocyte expression of RNA species encoding K(V)alpha1 subunits as well as K(V)beta1, K(V)alpha2.1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Ca)beta1. The seven major KCNA genes were expressed and more readily detected in endothelium-denuded mesenteric resistance artery compared with thoracic aorta; quantification revealed dramatic differential expression of one to two orders of magnitude. There was also four times more RNA encoding K(V)alpha2.1 but less or similar amounts encoding K(V)beta1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Cabeta)1. Patch-clamp recordings from freshly isolated smooth muscle cells revealed dominant K(V)alpha1 K(+) current and current density twice as large in mesenteric cells. Therefore, we suggest the increased RNA production of the resistance artery impacts on physiological function, although there is quantitatively less K(+) current than might be expected. The mechanism conferring up-regulated expression of KCNA genes may be common to all the gene family and play a functional role in the physiological control of blood pressure.

Physicians-in-training recommendations for prophylactic bilateral mastectomies

The decision to recommend bilateral prophylactic mastectomy (PBM), one treatment modality used to reduce the development of breast carcinoma, may be influenced by physician bias. This investigation tested the hypothesis that there are physician-in-training biases in recommendations of PBM. All second-year medical students, general surgical residents, and internal medicine residents at our institution participated in a survey in which they were asked at what percent risk of developing breast carcinoma the physicians-in-training would recommend PBM for 1) their patients, 2) themselves, and 3) their significant others, as applicable. A total of 198 physicians-in-training responded. Univariate analysis demonstrated an association between both the type of physician-in-training (p<0.03) and gender (p<0.004) with the percent risk for which respondents would recommend PBM. However, with multivariate analysis, only gender was associated with percent risk (p<0.05). Physicians-in-training also chose PBM at a lower risk for their significant others than for themselves (67.5% versus 57.2%; p<0.02). Respondents also chose PBM at a similar risk for themselves or significant others as for their patients (r=0.83, r=0.98; p<0.001). This investigation suggests that males (compared to females) are more likely to recommend PBM for the prevention of breast cancer.

Effect of a short structured session on medical student breast cancer screening knowledge

Formalized instruction in breast cancer screening during medical school may help improve early breast cancer detection and survival. Physicians-in-training must be proficient in skills relating to breast cancer screening. This study investigates the baseline breast cancer screening knowledge of medical students, the benefit of a structured lecture session, and its effect on improving medical students' knowledge of cancer screening. A self-administrated questionnaire relating to breast cancer screening was given to third-year medical students. A 60-minute structured lecture session was given to the medical students regarding breast cancer screening. A postintervention survey was administered immediately following the session. A total of 27 medical students were evaluated. There was a statistically significant improvement following the formalized teaching session (84% to 93%; p < 0.0016). While few students (15%) reported having previous instruction in cancer screening, most students (96%) felt that a formal session should be offered during medical school. While medical student knowledge of breast cancer screening may be adequate, formalized instruction in breast cancer health practices can improve medical student knowledge. Most students had limited previous instruction in breast cancer prevention and welcomed the opportunity for structured training in breast cancer prevention, education, and detection. Until a formal course becomes a fundamental aspect of medical education, a short structured session should be instituted.

Pharmacological profile of store-operated channels in cerebral arteriolar smooth muscle cells

1. In this study, we determined a pharmacological profile of store-operated channels (SOCs) in smooth muscle cells of rabbit pial arterioles. Ca(2+)-indicator dyes, fura-PE3 or fluo-4, were used to track [Ca(2+)](i) and 10 micro M methoxyverapamil (D600) was present in all experiments on SOCs to prevent voltage-dependent Ca(2+) entry. Store depletion was induced using thapsigargin or cyclopiazonic acid. 2. SOC-mediated Ca(2+) entry was inhibited concentration dependently by Gd(3+) (IC(50) 101 nM). It was also inhibited by 10 micro M La(3+) (70% inhibition, N=5), 100 micro M Ni(2+) (57% inhibition, N=5), 75 micro M 2-aminoethoxydiphenylborate (66% inhibition, N=4), 100 micro M capsaicin (12% inhibition, N=3) or preincubation with 10 micro M wortmannin (76% inhibition, N=4). It was completely resistant to 1 micro M nifedipine (N=5), 10 micro M SKF96365 (N=6), 10 micro M LOE908 (N=14), 10-100 micro M ruthenium red (N=1+2), 100 micro M sulindac (N=4), 0.5 mM streptomycin (N=3) or 1 : 10,000 dilution Grammostolla spatulata venom (N=4). 3. RT-PCR experiments on isolated arteriolar fragments showed expression of mRNA species for TRPC1, 3, 4, 5 and 6. 4. The pharmacological profile of SOC-mediated Ca(2+) entry in arterioles supports the hypothesis that these SOCs are distinct from tonically active background channels and several store-operated and other nonselective cation channels described in other cells. Similarities with the pharmacology of TRPC1 support the hypothesis that TRPC1 is a subunit of the arteriolar smooth muscle SOC.

TRPC1 store-operated cationic channel subunit

TRPC1 is a membrane protein that is highly conserved in mammals, amphibians and birds. It is widely expressed in cells throughout the body including in the heart and nervous system. Amino acid sequence analysis and over-expression studies indicate it is an ion channel that allows the transmembrane flux of small cations including sodium and calcium. In some cell types it is apparent that at least a fraction of TRPC1 exists in the plasma membrane. Inhibition of TRPC1 expression or block by TRPC1-specific antibody leads to attenuation of the plasma membrane calcium influx that occurs in response to depletion of calcium levels in sarcoplasmic or endoplasmic reticulum. TRPC1 would, therefore, seem to be a key subunit of store-operated channels (SOCs). TRPC1 is, nevertheless, unlikely to act alone. There is good evidence that it can heteromultimerise with the related proteins TRPC4, TRPC5 and polycystin-2; a tetrameric arrangement is envisaged, but not demonstrated. Like its relative in Drosophila, TRPC1 looks likely to function in a signalplex, a protein complex including inositol 1,4,5-triphosphate (IP(3)) receptor, plasma membrane calcium-ATPase, caveolin-1 and calmodulin. Its localisation in membranes is punctate and associated with functionally discrete calcium signals. TRPC1's function may not only be linked to SOCs but also to other cellular events including the nuclear translocation of the NFAT transcription factor. There is still much to be learned about this fundamental protein.

Synchronous Occurrence of Glioblastoma Multiforme and Esophageal Adenocarcinoma

Synchronous malignancies are rare occurrences for which there may be a genetic link between two cancers or which may be simply coincidental. Although glioblastoma multiforme and esophageal adenocarcinoma have few clinical similarities there are no known biochemical or genetic links between the two malignancies. This case discussion details the synchronous occurrences of these two lesions and highlights possible clinical, biochemical, and genetic commonalities.