The identification of the molecular drivers of cancer by sequencing is the backbone of precision medicine and the basis of personalized therapy; however, biopsies of primary tumors provide only a ...snapshot of the evolution of the disease and may miss potential therapeutic targets, especially in the metastatic setting. A liquid biopsy, in the form of cell-free DNA (cfDNA) sequencing, has the potential to capture the inter- and intra-tumoral heterogeneity present in metastatic disease, and, through serial blood draws, track the evolution of the tumor genome. In order to determine the clinical utility of cfDNA sequencing we performed whole-exome sequencing on cfDNA and tumor DNA from two patients with metastatic disease; only minor modifications to our sequencing and analysis pipelines were required for sequencing and mutation calling of cfDNA. The first patient had metastatic sarcoma and 47 of 48 mutations present in the primary tumor were also found in the cell-free DNA. The second patient had metastatic breast cancer and sequencing identified an ESR1 mutation in the cfDNA and metastatic site, but not in the primary tumor. This likely explains tumor progression on Anastrozole. Significant heterogeneity between the primary and metastatic tumors, with cfDNA reflecting the metastases, suggested separation from the primary lesion early in tumor evolution. This is best illustrated by an activating PIK3CA mutation (H1047R) which was clonal in the primary tumor, but completely absent from either the metastasis or cfDNA. Here we show that cfDNA sequencing supplies clinically actionable information with minimal risks compared to metastatic biopsies. This study demonstrates the utility of whole-exome sequencing of cell-free DNA from patients with metastatic disease. cfDNA sequencing identified an ESR1 mutation, potentially explaining a patient's resistance to aromatase inhibition, and gave insight into how metastatic lesions differ from the primary tumor.
AtT-20 cells expressing the wild-type kappa opioid receptor (KOR) increased phospho-p38 MAPK following treatment with the kappa agonist U50,488. The increase was blocked by the kappa antagonist ...norbinaltorphimine and not evident in untransfected cells. In contrast, U50,488 treatment of AtT-20 cells expressing KOR having alanine substituted for serine-369 (KSA) did not increase phospho-p38. Phosphorylation of serine 369 in the KOR carboxyl terminus by G-protein receptor kinase 3 (GRK3) was previously shown to be required for receptor desensitization, and the results suggest that p38 MAPK activation by KOR may require arrestin recruitment. This hypothesis was tested by transfecting arrestin3-(R170E), a dominant positive form of arrestin that does not require receptor phosphorylation for activation. AtT-20 cells expressing both KSA and arrestin3-(R170E) responded to U50,488 treatment with an increase in phospho-p38 consistent with the hypothesis. Primary cultured astrocytes (glial fibrillary acidic protein-positive) and neurons (γ-aminobutyric acid-positive) isolated from mouse striata also responded to U50,488 by increasing phospho-p38 immunolabeling. p38 activation was not evident in either striatal astrocytes or neurons isolated from KOR knock-out mice or GRK3 knock-out mice. Astrocytes pretreated with small interfering RNA for arrestin3 were also unable to activate p38 in response to U50,488 treatment. Furthermore, in striatal neurons, the kappa-mediated phospho-p38 labeling was colocalized with arrestin3. These findings suggest that KOR may activate p38 MAPK in brain by a GRK3 and arrestin-dependent mechanism.
The calcium-permeable transient receptor potential M2 (TRPM2) ion channel was recently demonstrated to have a sexually dimorphic contribution to ischemic brain injury, with inhibition or knockdown of ...the channel protecting male brain preferentially. We tested the hypothesis that androgen signaling is required for this male-specific cell-death pathway. Additionally, we tested the hypothesis that differential activation of the enzyme poly (ADP-ribose) polymerase-1 (PARP-1) is responsible for male-specific TRPM2 channel activation and neuronal injury. We observed that administration of the TRPM2 inhibitor clotrimazole (CTZ) 2 hours after onset of ischemia reduced infarct volume in male mice and that protection from ischemic damage by CTZ was abolished by removal of testicular androgens (castration; CAST) and rescued by androgen replacement. Male PARP-1 knockout mice had reduced ischemic damage compared with WT mice and inhibition of TRPM2 with CTZ failed to reduce infarct size. Lastly, we observed that ischemia increased PARP activity in the peri-infarct region of male mice to a greater extent than female mice and the difference was abolished in CAST male mice. Data presented in the current study indicate that TRPM2-mediated neuronal death in the male brain requires intact androgen signaling and PARP-1 activity.
In this study we investigated the mechanisms responsible for MAP kinase ERK1/2 activation following agonist activation of endogenous mu opioid receptors (MOR) normally expressed in cultured striatal ...neurons. Treatment with the MOR agonist fentanyl caused significant activation of ERK1/2 in neurons derived from wild type mice. Fentanyl effects were blocked by the opioid antagonist naloxone and were not evident in neurons derived from MOR knock-out (-/-) mice. In contrast, ERK1/2 activation by fentanyl was not evident in neurons from GRK3-/- mice or neurons pretreated with small inhibitory RNA for arrestin3. Consistent with this observation, treatment with the opiate morphine (which is less able to activate arrestin) did not elicit ERK1/2 activation in wild type neurons; however, transfection of arrestin3-(R170E) (a dominant positive form of arrestin that does not require receptor phosphorylation for activation) enabled morphine activation of ERK1/2. In addition, activation of ERK1/2 by fentanyl and morphine was rescued in GRK3-/- neurons following transfection with dominant positive arrestin3-(R170E). The activation of ERK1/2 appeared to be selective as p38 MAP kinase activation was not increased by either fentanyl or morphine treatment in neurons from wild type, MOR-/-, or GRK3-/- mice. In addition, U0126 (a selective inhibitor of MEK kinase responsible for ERK phosphorylation) blocked ERK1/2 activation by fentanyl. These results support the hypothesis that MOR activation of ERK1/2 requires opioid receptor phosphorylation by GRK3 and association of arrestin3 to initiate the cascade resulting in ERK1/2 phosphorylation in striatal neurons.
Opioids activate the descending antinociceptive pathway from the ventrolateral periaqueductal gray (vlPAG) by both pre- and postsynaptic inhibition of tonically active GABAergic neurons (i.e., ...disinhibition). Previous research has shown that short-term desensitization of postsynaptic μ-opioid receptors (MOPrs) in the vlPAG is increased with the development of opioid tolerance. Given that pre- and postsynaptic MOPrs are coupled to different signaling mechanisms, the present study tested the hypothesis that short-term desensitization of presynaptic MOPrs also contributes to opioid tolerance. Twice-daily injections of morphine (5 mg/kg s.c.) for 2 days caused a rightward shift in the morphine dose-response curve on the hot plate test (D(50) = 9.9 mg/kg) compared with saline-pretreated (5.3 mg/kg) male Sprague-Dawley rats. In vitro whole-cell patch-clamp recordings from vlPAG slices revealed that inhibition of evoked inhibitory postsynaptic currents (eIPSCs) by the MOPr-selective agonist d-Ala(2),N-Me-Phe(4),Gly(5)-ol-enkephalin was decreased in morphine-tolerant (EC(50) = 708 nM) compared with saline-pretreated rats (EC(50) = 163 nM). However, short-term desensitization of MOPr inhibition of eIPSCs was not observed in either saline- or morphine-pretreated rats. Reducing the number of available MOPrs with the irreversible opioid receptor antagonist, β-chlornaltrexamine decreased maximal MOPr inhibition with no evidence of desensitization, indicating that the lack of observed desensitization is not caused by receptor reserve. These results demonstrate that tolerance to the antinociceptive effect of morphine is associated with a decrease in presynaptic MOPr sensitivity or coupling to effectors, but this change is independent of short-term MOPr desensitization.
Objectives. Little is known about the treatment Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans receive for chronic noncancer pain (CNCP). We sought to describe the prevalence ...of prescription opioid use, types, and doses of opioids received and to identify correlates of receiving prescription opioids for CNCP among OEF/OIF veterans.
Design. Retrospective review of Veterans Affairs (VA) administrative data.
Setting. Ambulatory clinics within a VA regional health care network.
Patients. OEF/OIF veterans who had at least three elevated pain screening scores within a 12‐month period in 2008. Within this group, those prescribed opioids (N = 485) over the next 12 months were compared with those not prescribed opioids (N = 277). In addition, patients receiving opioids short term (<90 days, N = 284) were compared with patients receiving them long term (≥90 consecutive days, N = 201).
Results. Of 762 OEF/OIF veterans with CNCP, 64% were prescribed at least one opioid medication over the 12 months following their index dates. Of those prescribed an opioid, 59% were prescribed opioids short term and 41% were prescribed opioids long term. The average morphine‐equivalent opioid dose for short‐term users was 23.7 mg (standard deviation SD = 20.5) compared with 40.8 mg (SD = 36.1) for long‐term users (P < 0.001). Fifty‐one percent of long‐term opioid users were prescribed short‐acting opioids only, and one‐third were also prescribed sedative hypnotics. In adjusted analyses, diagnoses of low back pain, migraine headache, posttraumatic stress disorder, and nicotine use disorder were associated with an increased likelihood of receiving an opioid prescription.
Conclusion. Prescription opioid use is common among OEF/OIF veterans with CNCP and is associated with several pain diagnoses and medical conditions.
Repeated administration of opioids produces long-lasting changes in micro-opioid receptor (MOR) signaling that underlie behavioral changes such as tolerance. Mitogen-activated protein kinase (MAPK) ...pathways, including MAPK extracellular signal-regulated kinases (ERK1/2), are modulated by opioids and are known to produce long-lasting changes in cell signaling. Thus, we tested the hypothesis that ERK1/2 activation contributes to the development and/or expression of morphine tolerance mediated by the periaqueductal gray (PAG). Changes in phosphorylated ERK1/2 expression were assessed with confocal microscopy and compared to behavioral measures of tolerance to the antinociceptive effects of chronic morphine administration. Repeated microinjection of morphine into the PAG produced tolerance and caused a significant increase in ERK1/2 phosphorylation, an effect not evident with acute morphine microinjection. Microinjection of the MAPK/ERK kinase inhibitor, 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene ethanolate (U0126), into the PAG had no effect on antinociception produced by acute morphine administration. However, repeated coadministration of U0126 and morphine into the PAG blocked ERK1/2 phosphorylation and enhanced the development of morphine tolerance. Coadministration of U0126 with morphine only on the test day also enhanced the expression of morphine tolerance. Administration of the irreversible opioid receptor antagonist beta-chlornaltrexamine blocked the activation of ERK1/2 caused by repeated morphine microinjections, demonstrating that ERK1/2 activation was a MOR-mediated event. In summary, these studies show that chronic morphine administration alters ERK1/2 signaling and that disruption of ERK1/2 signaling enhances both the development and expression of morphine tolerance. Contrary to expectations, these data indicate that ERK1/2 activation opposes the development of morphine tolerance.
Objective
Despite a growing number of women seeking medical care in the veterans affairs (VA) system, little is known about the characteristics of their chronic pain or the pain care they receive. ...This study sought to determine if sex differences are present in the medical care veterans received for chronic pain.
Design
Retrospective cohort study using VA administrative data.
Subjects
The subjects were 17,583 veteran patients with moderate to severe chronic non‐cancer pain treated in the Pacific Northwest during 2008.
Methods
Multivariate logistic regression assessed for sex differences in primary care utilization, prescription of chronic opioid therapy, visits to emergency departments for a pain‐related diagnosis, and physical therapy referral.
Results
Compared with male veterans, female veterans were more often diagnosed with two or more pain conditions, and had more of the following pain‐related diagnoses: fibromyalgia, low back pain, inflammatory bowel disease, migraine headache, neck or joint pain, and arthritis. After adjustment for demographic characteristics, pain diagnoses, mental health diagnoses, substance use disorders, and medical comorbidity, women had lower odds of being prescribed chronic opioid therapy (adjusted OR AOR 0.67, 95% CI 0.58–0.78), greater odds of visiting an emergency department for a pain‐related complaint (AOR 1.40, 95% CI 1.18–1.65), and greater odds of receiving physical therapy (AOR 1.19, 95% CI 1.05–1.33). Primary care utilization was not significantly different between sexes.
Conclusions
Sex differences are present in the care female veterans receive for chronic pain. Further research is necessary to understand the etiology of the observed differences and their associations with clinical outcomes.
PURPOSEPharmacistsʼ satisfaction with a computerized prescriber order-entry (CPOE) system and the impact of CPOE on pharmacy workflows and order verification were investigated.
SUMMARYA mixed-method ...study was conducted to evaluate the implementation of a CPOE system in three hospitals of a large Michigan-based health system and early user experience with the system. Surveys of pharmacists before (n = 54) and after (n = 42) CPOE implementation indicated that they held generally positive expectations about CPOE prior to and during system implementation and continued to hold positive views about CPOE after several months of system use. In interviews and focus group discussions, pharmacists reported a number of important CPOE benefits, but they also cited challenges related to CPOE provider alerts, uncertainty about medication timing, and the need to support providers by serving as informal CPOE system trainers. Direct observation of pharmacists before and after CPOE implementation indicated decreases in both the rate of order clarification events (from 0.89 to 0.35 per hour, p < 0.001) and the average time spent per hour clarifying orders (from 4.75 to 2.11 minutes, p = 0.008).
CONCLUSIONSeveral months after CPOE implementation, pharmacists indicated that several aspects of their workload had improved, including the process of medication order clarification, their ability to prioritize work, and their ability to move around within the hospital to respond to demand. However, pharmacists also noted that order ambiguity still existed and that the system needed to be optimized to gain efficiencies and increase clarity.
Tolerance to the pain-relieving effects of opiates limits their clinical use. Although morphine tolerance is associated with desensitization of mu-opioid receptors, the underlying cellular mechanisms ...are not understood. One problem with the desensitization hypothesis is that acute morphine does not readily desensitize mu-opioid receptors in many cell types. Given that neurons in the periaqueductal gray (PAG) contribute to morphine antinociception and tolerance, an understanding of desensitization in PAG neurons is particularly relevant. Opioid activity in the PAG can be monitored with activation of G-protein-mediated inwardly rectifying potassium (GIRK) currents. The present data show that opioids have a biphasic effect on GIRK currents in morphine tolerant rats. Opioid activation of GIRK currents is initially potentiated in morphine (EC(50)=281 nM) compared to saline (EC(50)=8.8 microM) pretreated rats as indicated by a leftward shift in the concentration-response curve for met-enkephalin (ME)-induced currents. These currents were inhibited by superfusion of the mu-opioid receptor antagonist beta-funaltrexamine (beta-FNA) suggesting that repeated morphine administration enhances agonist stimulation of mu-opioid receptor coupling to G-proteins. Although supersensitivity of mu-opioid receptors in the PAG is counterintuitive to the development of tolerance, peak GIRK currents from tolerant rats desensitized more than currents from saline pretreated rats (56% of peak current after 10 min compared to 15%, respectively). These data indicate that antinociceptive tolerance may be triggered by enhanced agonist potency resulting in increased desensitization of mu-opioid receptors.
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