Cooperative interactions between growth factor signaling pathways are important elements in carcinoma progression. A model system combining transforming growth factor-β1 (TGF-β1) and EGF was developed to investigate mechanisms underlying induced epithelial-to-mesenchymal transition (EMT) in ras-transformed human (HaCaT II-4) keratinocytes. Dual stimulation with TGF-β1+EGF resulted in keratinocyte “plasticity” and pronounced colony dispersal. The most highly expressed transcript, identified by mRNA profiling, encoded plasminogen activator inhibitor-1 (PAI-1; SERPINE1). PAI-1 negatively regulates plasmin-dependent matrix degradation, preserving a stromal scaffold permissive for keratinocyte motility. Mitogen-activated extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK) and p38 signaling were required for maximal PAI-1 upregulation and TGF-β1+EGF-stimulated cell locomotion, as pharmacologic disruption of MEK/p38 activity ablated both responses. Moreover, PAI-1 knockdown alone effectively inhibited TGF-β1+EGF-dependent cell scattering, indicating a functional role for this SERPIN in the dual-growth factor model of induced motility. Moreover, EGFR signaling blockade or EGFR knockdown attenuated TGF-β1-induced PAI-1 expression, implicating EGFR transactivation in TGF-β1-stimulated PAI-1 expression, and reduced colony dispersal in TGF-β1+EGF-treated cultures. Identification of such cooperative signaling networks and their effect on specific invasion-promoting target genes, such as PAI-1, may lead to the development of pathway-specific therapeutics that affect late-stage events in human tumor progression.
Prevalence of cigarette smoking among opioid-maintained patients is more than threefold that of the general population and associated with increased morbidity and mortality. Relatively few studies have evaluated smoking interventions in this population. The purpose of the present study was to examine the efficacy of contingency management for promoting initial smoking abstinence. Forty methadone- or buprenorphine-maintained cigarette smokers were randomly assigned to a contingent (n = 20) or noncontingent (n = 20) experimental group and visited the clinic for 14 consecutive days. Contingent participants received vouchers based on breath carbon monoxide levels during Study Days 1 to 5 and urinary cotinine levels during Days 6 to 14. Voucher earnings began at $9.00 and increased by $1.50 with each subsequent negative sample for maximum possible of $362.50. Noncontingent participants earned vouchers independent of smoking status. Although not a primary focus, participants who were interested and medically eligible could also receive bupropion (Zyban). Contingent participants achieved significantly more initial smoking abstinence, as evidenced by a greater percentage of smoking-negative samples (55% vs. 17%) and longer duration of continuous abstinence (7.7 vs. 2.4 days) during the 2 week quit attempt than noncontingent participants, respectively. Bupropion did not significantly influence abstinence outcomes. Results from this randomized clinical trial support the efficacy of contingency management interventions in promoting initial smoking abstinence in this challenging population.
contingency management; smoking cessation; methadone; buprenorphine; bupropion
Chronic kidney disease constitutes an increasing medical burden affecting 26 million people in the United States alone. Diabetes, hypertension, ischemia, acute injury, and urological obstruction contribute to renal fibrosis, a common pathological hallmark of chronic kidney disease. Regardless of etiology, elevated TGF-β1 levels are causatively linked to the activation of profibrotic signaling pathways initiated by angiotensin, glucose, and oxidative stress. Unilateral ureteral obstruction (UUO) is a useful and accessible model to identify mechanisms underlying the progression of renal fibrosis. Plasminogen activator inhibitor-1 (PAI-1), a major effector and downstream target of TGF-β1 in the progression of several clinically important fibrotic disorders, is highly up-regulated in UUO and causatively linked to disease severity. SMAD and non-SMAD pathways (pp60c-src, epidermal growth factor receptor [EGFR], mitogen-activated protein kinase, p53) are required for PAI-1 induction by TGF-β1. SMAD2/3, pp60c-src, EGFR, and p53 activation are each increased in the obstructed kidney. This review summarizes the molecular basis and translational significance of TGF-β1-stimulated PAI-1 expression in the progression of kidney disease induced by ureteral obstruction. Mechanisms discussed here appear to be operative in other renal fibrotic disorders and are relevant to the global issue of tissue fibrosis, regardless of organ site.
Fibrosis; PAI-1; TGF-β1; p53; Transcription
Decreasing smoking during pregnancy is an important public health priority. An important step towards decreasing smoking during pregnancy is wider dissemination of evidence-based smoking cessation interventions. One such intervention is contingency management wherein mothers earn vouchers exchangeable for retail items contingent on biochemically-verified smoking abstinence. Wider dissemination may be possible by using smoking verification methods that require minimal training and equipment. One possibility is to use a cotinine-sensitive dipstick (NicAlert) rather than a bench-top cotinine analyzer, which is expensive and requires relatively extensive technician expertise, or breath carbon monoxide analysis, which is relatively nonspecific. The present study was conducted to begin examining the utility of cotinine-sensitive dipsticks for this purpose.
Fifty urine samples from pregnant women enrolled in a smoking cessation program were analyzed to compare three different methods for verifying smoking status: NicAlert strips, a bench-top enzyme multiplied immunoassay technique (EMIT) analyzer, and gas chromatography (GC), the current gold standard for determining cotinine levels in urine.
Agreement between GC and NicAlert results were high (96%) and comparable to agreement between GC and EMIT results (94%). Semi-quantitative measurements using NicAlert were low with only 30% of samples in agreement between GC and specific ranges given on the strips.
NicAlert strips appear to be a valid measure of determining smoking status among pregnant smokers although not of absolute cotinine concentration. With minimal training and equipment required, NicAlert strips provide a potentially practical method for using urine cotinine to verify smoking status in community treatment settings.
NicAlert; urine cotinine; pregnant smokers; gas chromatography; smoking status; biochemical verification; contingency management
The association between buprenorphine taper duration and treatment outcomes is not well understood. This review evaluated whether duration of outpatient buprenorphine taper is significantly associated with treatment outcomes.
Studies that were published in peer-reviewed journals, administered buprenorphine as an outpatient taper to opioid-dependent participants, and provided data on at least one of three primary treatment outcome measures (opioid abstinence, retention, peak withdrawal severity) were reviewed. Primary treatment outcomes were evaluated as a function of taper duration using hierarchical linear regressions using pre-taper maintenance as a cofactor.
Twenty-eight studies were reviewed. Taper duration significantly predicted percent of opioid-negative samples provided during treatment, however pre-taper maintenance period predicted percent participants abstinent on the final day of treatment. High rates of relapse were reported. No significant association between taper duration and retention in treatment or peak withdrawal severity was observed.
The data reviewed here suggest taper duration is associated with opioid abstinence achieved during detoxification but not with other markers of treatment outcome. The reviewed studies varied widely on several parameters (e.g., frequency of urinalysis testing, provision of ancillary medications) that may influence treatment outcome and thus could have interfered with the ability to identify relationships between taper duration and outcomes. Future studies evaluating opioid detoxification should utilize rigorous experimental methods and report a wider range of outcome measures in order to help advance our understanding of the association between taper duration and treatment outcomes.
opioid; buprenorphine; taper; detoxification; withdrawal; outpatient
Delay discounting (DD) describes the rate at which reinforcers lose value as the temporal delay to their receipt increases. Steeper discounting has been positively associated with vulnerability to substance use disorders, including cocaine use disorders.
In the present study, we examined whether DD of hypothetical monetary reinforcers is associated with the duration of cocaine abstinence achieved among cocaine-dependent outpatients.
Participants were 36 adults who were participating in a randomized controlled trial examining the efficacy of voucher-based contingency management (CM) using low-magnitude (N = 18) or high-magnitude (N = 18) voucher monetary values.
DD was associated with the number of continuous weeks of cocaine abstinence achieved, even after adjusting for treatment condition during the initial 12-week (t(33) = 2.48, p = .045) and entire recommended 24-week of treatment (t(33) = 2.40, p = .022). Participants who exhibited steeper discounting functions achieved shorter periods of abstinence in the Low-magnitude voucher condition (12-week: t(16) = 2.48, p = .025; 24-week: t(16) = 2.68, p = .017), but not in the High-magnitude voucher condition (12-week: t(16) = 0.51, p = .618; 24-week: t(16) = 1.08, p = .298), although the interaction between DD and treatment condition was not significant (12-week: t(32) = −1.12, p = .271; 24-week: t(32) = −0.37, p = .712).
These results provide further evidence on associations between DD and treatment response and extend those observations to a new clinical population (i.e., cocaine-dependent outpatients), while also suggesting that a more intensive intervention like the High-magnitude CM condition may diminish this negative relationship between DD and treatment response.
Temporal discounting; delay discounting; cocaine dependence; contingency management; vouchers; treatment response
Excessive maternal weight gain during pregnancy can result in serious adverse maternal and neonatal health consequences making it an important outcome to monitor in developing smoking-cessation interventions for pregnant women. Maternal weight gain was investigated in the present study with 154 pregnant participants in controlled trials investigating the efficacy of contingency management (CM) for smoking cessation. Women were assigned to either an abstinence-contingent condition wherein they earned vouchers exchangeable for retail items by abstaining from smoking or to a control condition where they received comparable vouchers independent of smoking status. Mean percent of negative smoking status tests throughout antepartum was greater in the incentive than control condition (45.2±4.6 vs. 15.5±2.4, p < .001) as was late-pregnancy point-prevalence abstinence (36% vs. 8%, p < .001) but maternal weight gain did not differ significantly between treatment conditions (15.0 ± 0.8 kg vs. 15.0 ± 0.9 kg, p = .97). In a comparison of women classified by smoking status rather than treatment condition, a greater percent of negative smoking status tests predicted significantly more weight gain (0.34 kg per 10% increase in negative tests), an effect that appeared to be attributable to women with greater abstinence having larger infants. This study shows no evidence of excessive maternal weight gain among pregnant women receiving a CM intervention for smoking cessation.
Maternal weight gain; smoking cessation; pregnancy; contingency management; vouchers
Spatial and temporal regulation of the pericellular proteolytic environment by local growth factors, such as EGF and TGF-β, initiates a wide repertoire of cellular responses coupled to a plasmin/matrix metalloproteinase (MMP) dependent stromal-remodeling axis. Cell motility and invasion, tumor metastasis, wound healing, and organ fibrosis, for example, represent diverse events controlled by expression of a subset of genes that encode various classes of tissue remodeling proteins. These include members of the serine protease and MMP families that functionally constitute a complex system of interacting protease cascades and titrated by their respective inhibitors. Several structural components of the extracellular matrix are upregulated by TGF-β as are matrix-active proteases (e.g., urokinase (uPA), plasmin, MMP-1, -3, -9, -10, -11, -13, -14). Stringent controls on serine protease/MMP expression and their topographic activity are essential for maintaining tissue homeostasis. Targeting individual elements in this highly interactive network may lead to novel therapeutic approaches for the treatment of cancer, fibrotic diseases, and chronic wounds.
This study combined data from three controlled trials to examine whether smoking cessation using voucher-based contingency management (CM) improves birth outcomes.
Participants (N = 166) were pregnant women who participated in trials examining the efficacy of voucher-based CM for smoking cessation. Women were assigned to either a contingent condition wherein they earned vouchers exchangeable for retail items by abstaining from smoking or to a noncontingent condition where they received vouchers independent of smoking status. Birth outcomes were determined by review of hospital delivery records.
Antepartum abstinence was greater in the contingent than noncontingent condition, with late-pregnancy abstinence being 34.1% vs. 7.4% (p < .001). Mean birth weight of infants born to mothers treated in the contingent condition was greater than infants born to mothers treated in the noncontingent condition (3295.6 ± 63.8 g vs. 3093.6 ± 67.0 g, p = .03) and the percent of low birth weight (< 2500g) deliveries was less (5.9% vs. 18.5%, p = .02). No significant treatment effects were observed across three other outcomes investigated although each was in the direction of improved outcomes in the contingent vs. the noncontingent condition: mean gestational age (39.1 ± 0.2 weeks vs. 38.5 ± 0.3 weeks, p = .06), percent of preterm deliveries (5.9 vs. 13.6, p = .09), and percent admissions to the Neonatal Intensive Care Unit (4.7% vs. 13.8%, p = .06).
These results provide evidence that smoking-cessation treatment with voucher-based CM may improve important birth outcomes.
vouchers; contingency management; birth outcomes; gestational age; preterm birth; birth weight; low birth weight; cigarette smoking; smoking cessation
This essay discusses research on incentive-based interventions to promote healthy behavior change, contingency management (CM) and conditional cash transfers (CCT). The overarching point of the essay is that CM and CCT are often treated as distinct areas of inquiry when at their core they represent a common approach. Some potential bi-directional benefits of recognizing this commonality are discussed. Distinct intellectual traditions probably account for the separate paths of CM and CCT to date, with the former being rooted in behavioral psychology and the latter in microeconomics. It is concluded that the emerging field of behavioral economics, which is informed by and integrates principles of each of those disciplines, may provide the proper conceptual framework for integrating CM and CCT.
contingency management; conditional cash transfers; incentive-based interventions
Malignant transformation of mammalian cells with ras family oncogenes results in dramatic changes in cellular architecture and growth traits. The generation of flat revertants of v-K-ras-transformed renal cells by exposure to the histone deacetylase inhibitor sodium butyrate (NaB) was previously found to be dependent on transcriptional activation of the PAI-1 (SERPINE1) gene (encoding the type-1 inhibitor of urokinase and tissue-type plasminogen activators). NaB-initiated PAI-1 expression preceded induced cell spreading and entry into G1 arrest. To assess the relevance of PAI-1 induction to growth arrest in this cell system more critically, two complementary approaches were used. The addition of a stable, long half-life, recombinant PAI-1 mutant to PAI-1-deficient v-K-ras-/c-Ha-ras-transformants or to PAI-1 functionally null, NaB-resistant, 4HH cells (engineered by antisense knockdown of PAI-1 mRNA transcripts) resulted in marked cytostasis in the absence of NaB. The transfection of ras-transformed cells with the Rc/CMVPAI expression construct, moreover, significantly elevated constitutive PAI-1 synthesis (10- to 20-fold) with a concomitant reduction in proliferative rate. These data suggest that high-level PAI-1 expression suppresses growth of chronic ras-oncogene transformed cells and is likely a major cytostatic effector of NaB exposure.
Cellular migration, over simple surfaces or through complex stromal barriers, requires coordination between detachment/re-adhesion cycles, involving structural components of the extracellular matrix and their surface-binding elements (integrins), and the precise regulation of the pericellular proteolytic microenvironment. It is now apparent that several proteases and protease inhibitors, most notably urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1), also interact with several cell surface receptors transducing intracellular signals that significantly affect both motile and proliferative programs. These events appear distinct from the original function of uPA/PAI-1 as modulators of the plasmin-based proteolytic cascade. The multifaceted interactions of PAI-1 with specific matrix components (i.e., vitronectin), the low-density lipoprotein receptor-related protein-1 (LRP1), and the uPA/uPA receptor complex have dramatic consequences on the migratory phenotype and may underlie the pathophysiologic sequalae of PAI-1 deficiency and overexpression. This paper focuses on the increasingly intricate role of PAI-1 as a major mechanistic determinant of the cellular migratory phenotype.
Plasminogen activator inhibitor-1 (PAI-1), a major regulator of the plasmin-based pericellular proteolytic cascade, is significantly increased in human arterial plaques contributing to vessel fibrosis, arteriosclerosis and thrombosis, particularly in the context of elevated tissue TGF-β1. Identification of molecular events underlying to PAI-1 induction in response to TGF-β1 may yield novel targets for the therapy of cardiovascular disease.
Reactive oxygen species are generated within 5 minutes after addition of TGF-β1 to quiescent vascular smooth muscle cells (VSMCs) resulting in pp60c-src activation and PAI-1 expression. TGF-β1-stimulated Src kinase signaling sustained the duration (but not the initiation) of SMAD3 phosphorylation in VSMC by reducing the levels of PPM1A, a recently identified C-terminal SMAD2/3 phosphatase, thereby maintaining SMAD2/3 in an active state with retention of PAI-1 transcription. The markedly increased PPM1A levels in triple Src kinase (c-Src, Yes, Fyn)-null fibroblasts are consistent with reductions in both SMAD3 phosphorylation and PAI-1 expression in response to TGF-β1 compared to wild-type cells. Activation of the Rho-ROCK pathway was mediated by Src kinases and required for PAI-1 induction in TGF-β1-stimulated VSMCs. Inhibition of Rho-ROCK signaling blocked the TGF-β1-mediated decrease in nuclear PPM1A content and effectively attenuated PAI-1 expression. TGF-β1-induced PAI-1 expression was undetectable in caveolin-1-null cells, correlating with the reduced Rho-GTP loading and SMAD2/3 phosphorylation evident in TGF-β1-treated caveolin-1-deficient cells relative to their wild-type counterparts. Src kinases, moreover, were critical upstream effectors of caveolin-1Y14 phosphoryation and initiation of downstream signaling.
TGF-β1-initiated Src-dependent caveolin-1Y14 phosphorylation is a critical event in Rho-ROCK-mediated suppression of nuclear PPM1A levels maintaining, thereby, SMAD2/3-dependent transcription of the PAI-1 gene.
A symposium held at the 50th annual meeting of the Behavioral Pharmacology Society in May 2007 reviewed progress in the human behavioral pharmacology of drug abuse. Studies on drug self-administration in humans are reviewed that assessed reinforcing and subjective effects of drugs of abuse. The close parallels observed between studies in humans and laboratory animals using similar behavioral techniques have broadened our understanding of the complex nature of the pharmacological and behavioral factors controlling drug self-administration. The symposium also addressed the role that individual differences, such as gender, personality, and genotype play in determining the extent of self-administration of illicit drugs in human populations. Knowledge of how these factors influence human drug self-administration has helped validate similar differences observed in laboratory animals. In recognition that drug self-administration is but one of many choices available in the lives of humans, the symposium addressed the ways in which choice behavior can be studied in humans. These choice studies in human drug abusers have opened up new and exciting avenues of research in laboratory animals. Finally, the symposium reviewed behavioral pharmacology studies conducted in drug abuse treatment settings and the therapeutic benefits that have emerged from these studies.
The purpose of this study was to use data from controlled trials to examine whether smoking cessation increases breastfeeding duration. Correlational studies have confirmed associations between smoking status and breastfeeding duration, but whether smoking cessation increases breastfeeding duration has not been established.
Participants (N = 158) were smokers at the start of prenatal care who participated in controlled trials on smoking cessation. Women were assigned to either an incentive-based intervention wherein they earned vouchers exchangeable for retail items by abstaining from smoking or a control condition where they received comparable vouchers independent of smoking status. Treatments were provided antepartum through 12-week postpartum. Maternal reports of breastfeeding collected at 2-, 4-, 8-, 12-, and 24-week postpartum were compared between treatment conditions. Whether women were exclusively breastfeeding was not investigated.
The incentive-based treatment significantly increased breastfeeding duration compared with rates observed among women receiving the control treatment, with significant differences between treatment conditions observed at 8-week (41% vs. 26%; odds ratio [OR] = 2.7, 95% CI = 1.3–5.6, p = .01) and 12-week (35% vs. 17%; OR = 3.4, 95% CI = 1.5–7.6, p = .002) postpartum. No significant treatment effects on breastfeeding were observed at other assessments. Changes in smoking status mediated the effects of treatment condition on breastfeeding duration.
These results provide evidence from controlled studies that smoking cessation increases breastfeeding duration, which, to our knowledge, has not been previously reported.
TGF-β1 and its target gene encoding plasminogen activator inhibitor-1 (PAI-1) are major regulators of capillary outgrowth, vessel maturation and angiogenic network stability. The increasing realization of the complexity of PAI-1 action in the vascular system requires analysis of specific signaling events that impact its expression in a physiologically-relevant cell system. PAI-1 was required for tubular differentiation and maintenance of cellular survival in complex gels since targeted disruption of PAI-1 synthesis or activity with antisense constructs or function-blocking antibodies resulted in network regression. Indeed, serum-deprivation-induced apoptosis of tubulogenic T2 cells was concentration-dependently inhibited by addition of a stable PAI-1 mutant protein consistent with the established pro-survival role of PAI-1 in vascular endothelial cells. PAI-1 induction and ERK pathway activation in response to TGF-β1 was attenuated by EGFR signaling blockade (with AG1478) or preincubation with the MMP/ADAM inhibitor GM6001. The combination of AG1478 + GM6001 completely ablated both responses suggesting that EGFR transactivation is important in PAI-1 gene control and may, at least partially, involve ligand shedding. TGF-β1-stimulated PAI-1 induction was preceded, in fact, by EGFR phosphorylation on Y845 (a src kinase target residue). EGFR1 knockdown with lentiviral shRNA constructs, moreover, effectively decreased (by >75%) TGF-β1-stimulated PAI-1 expression whereas infection with control (i.e. GFP) viruses had no effect. TGF-β1 failed to induce PAI-1 synthesis in EGFR-deficient fibroblasts while introduction of a wild-type EGFR1 construct in EGFR−/− cells rescued the PAI-1 response to TGF-β1 confirming, at a genetic level, the targeted knockdown data. The continued clarification of novel cooperative signaling cascades that impact expression of important angiogenic genes (e.g. PAI-1) may provide therapeutically useful targets to manage the pathophysiology of human neoplastic and vascular diseases.
SERPINE1; PAI-1; angiogenesis; TGF-β1; EGFR; apoptosis; tubulogenesis
Cigarette smoking remains a leading preventable cause of poor pregnancy outcomes and infant morbidity and mortality. Despite three decades of research encompassing more than 60 trials and 20,000 pregnant women, cessation rates produced by existing interventions are often low (< 20%), especially among socioeconomically disadvantaged women. This has led to a call for the development and testing of novel interventions. One strategy for identifying novel interventions for pregnant smokers is to examine efficacious interventions for other types of substance use disorders (SUDs). Pregnant smokers share many sociodemographic similarities with other sub-populations of individuals with SUDs, suggesting that interventions efficacious with the latter may also benefit the former. The National Institute on Drug Abuse’s guide, “Principles of Drug Addiction Treatment: A Research-based Guide”, presents empirically validated principles of effective treatments for other SUDs. The present report enumerates these principles, briefly describes some of the empirical evidence supporting them, and explores their potential application to the treatment of smoking during pregnancy. Overall, the results of this exercise suggest much promise for enhancing treatment outcomes for pregnant smokers by borrowing from and extending what has been learned with other populations with SUDs.
pregnant women; smoking cessation; substance use disorders; treatment; empirically validated
This study examined the influence of education on smoking status in a cohort (n = 316) of pregnant women who were smokers at the time they learned of the current pregnancy. Subjects were participants in clinical trials examining the efficacy of monetary-based incentives for smoking cessation and relapse prevention. In multivariate analyses, educational achievement was a robust predictor of smoking status upon entering prenatal care, of achieving abstinence antepartum among those still smoking at entry into prenatal care, and of smoking status at 6-months postpartum in the entire cohort and the subsample who received smoking-cessation treatment. In addition to educational attainment, other predictors of smoking status included smoking-related characteristics (e.g., number of cigarettes/day smoked pre-pregnancy), treatment, maternal age, and stress ratings. We suggest that strategies to increase educational attainment be included with more conventional tobacco-control policies in efforts to reduce smoking among girls and young women.
tobacco smoking; education; pregnancy; treatment; relapse prevention; health disparities; women
The current study assessed self-reported psychopathology in women who spontaneously quit or continued smoking after learning that they are pregnant and examined whether any potential differences remained after control for confounding variables. All participants (77 smokers and 50 spontaneous quitters) completed 3 assessments of psychological functioning prior to enrollment in either smoking cessation or relapse prevention studies. Assessments included the Brief Symptom Inventory (BSI); the Beck Depression Inventory (BDI); and the Adult Self-Report (ASR). Smokers and spontaneous quitters differed on sociodemographic and smoking characteristics. In terms of psychological functioning, smokers reported significantly more depression/anxiety symptoms and withdrawn behavior than spontaneous quitters on the BSI and the ASR. Higher depression scores on the BSI were associated with increased odds of continued smoking, even after controlling for sociodemographic and smoking variables in multivariate analyses. These results suggest that depressive symptoms may be an independent contributor to the problem of continued smoking during pregnancy, which may have implications for smoking-cessation interventions among pregnant women.
Pregnant women; pregnant smokers; spontaneous quitters; depression
Colchicine and nocodazole, both established microtubule disruptors, are useful tools to investigate cytoskeletal-dependent signaling cascades and the associated downstream transcriptional targets. Since cytoskeletal events impact pathophysiologic consequences in the vascular system, the signaling requirements underlying colchicine-stimulated expression of PAI-1 and CTGF, two prominent cell deformation-sensitive fibrosis-initiating proteins, were evaluated in vascular smooth muscle cells. Microtubule disruption rapidly induced EGFR transactivation (at the src kinase-sensitive EGFRY845 site) in a ROS-dependent manner. Genetic deficiency of EGFR, inhibition of EGFR signaling with AG1478 or introduction of a kinase-deficient EGFR construct effectively blocked colchicine-stimulated PAI-1 and CTGF expression. MEK/ERK involvement downstream of ROS generation was critical for PAI-1, but not CTGF, expression following cytoskeletal perturbation suggesting bifurcation of signaling pathways downstream of EGFR activation. Colchicine also stimulated SMAD2/3 phosphorylation by a Rho/ROCK-dependent mechanism independent of TGF-β1 release or receptor activity. Rho/ROCK signaling initiated by tubulin network collapse was required for both CTGF and PAI-1 induction. Colchicine-initiated SMAD3 phosphorylation, however, was essential for PAI-1, but not CTGF, expression further highlighting divergence of signaling events downstream of Rho/ROCK that mediate microtubule deformation-associated changes in profibrotic gene transcription.
PAI-1; CTGF; Microtubule Cytoskeleton; Colchicine; EGFR; SMAD; Rho/ROCK
Opioid treatment program patients and staff often have concerns that smoking cessation may jeopardize abstinence from illicit drug use. In this study, we evaluated whether smoking abstinence produced with a two-week contingency-management (CM) intervention was associated with relapse to illicit drug use among patients enrolled in opioid maintenance. Opioid-maintenance patients who were stable in treatment and abstinent from illicit drugs were enrolled in a 14-day smoking-cessation study. Participants were dichotomized into Abstainers (> 90% smoking-negative samples, n=12) and Smokers (< 10% smoking-negative samples, n=16). Illicit drug assays included opioids, oxycodone, propoxyphene, cannabis, amphetamines, cocaine and benzodiazepines. There were no differences between the Abstainers and Smokers, with 99% and 96% of samples testing negative for all illicit drugs in each group, respectively. Data from this study provide no evidence that smoking cessation among stable opioid-maintained patients undermines drug abstinence and lend support for programs that encourage smoking cessation during drug abuse treatment.
We examined the feasibility of brief outpatient detoxification as a treatment for prescription opioid (PO) abusers. Fifteen PO-dependent adults were enrolled to receive buprenorphine stabilization, a 2-week buprenorphine taper, and subsequent naltrexone for those who completed the taper. Subjects also received behavioral therapy, urinalysis monitoring, and double-blind drug administration. Subjects provided 83.8%, 91.7% and 31.2% opioid-negative samples during stabilization, taper and naltrexone phases, respectively. Inspection of individual subject data revealed systematic differences in whether subjects successfully completed the taper without resumption of illicit opioid use. Post-hoc analyses were used to examine the characteristics of subjects who successfully completed the taper (Responders, n=5) versus those who failed to do so (Nonresponders, n=9). These pilot data suggest a subset of PO abusers may respond to brief buprenorphine detoxification, though future efforts should aim to improve outcomes, investigate individual differences in treatment response and identify characteristics that may predict those for whom longer-term agonist treatment is warranted.
Prescription opioid abuse; Oxycodone; Opioid detoxification; Buprenorphine; Naltrexone
The emergence of highly aggressive subtypes of human cutaneous squamous cell carcinoma (SCC) often reflects increased autocrine/paracrine TGF-β synthesis and epidermal growth factor receptor (EGFR) amplification. Cooperative TGF-β/EGFR signaling promotes cell migration and induces expression of both proteases and protease inhibitors that regulate stromal remodeling resulting in the acquisition of an invasive phenotype. In one physiologically relevant model of human cutaneous SCC progression, TGF-β1+EGF stimulation increases the production of several matrix metalloproteinases (MMPs), among the most prominent of which is MMP-10—an MMP known to be elevated in SCC in situ. Activation of stromal plasminogen appears to be critical in triggering downstream MMP activity. Paradoxically, PAI-1, the major physiological inhibitor of plasmin generation, is also upregulated under these conditions and is an early event in progression of incipient epidermal SCC. One testable hypothesis proposes that TGF-β1+EGF-dependent MMP-10 elevation directs focalized matrix remodeling events that promote epithelial cell plasticity and tissue invasion. Increased PAI-1 expression serves to temporally and spatially modulate plasmin-initiated pericellular proteolysis, further facilitating epithelial invasive potential. Defining the complex signaling and transcriptional mechanisms that maintain this delicate balance is critical to developing targeted therapeutics for the treatment of human cutaneous malignancies.