"It frees your body from that pain thought": A mixed-methods exploration of patterns, contexts, and experiences of cannabis use for pain in rural communities.

U.S. adults increasingly report using cannabis to manage chronic pain and rural areas have inadequate comprehensive pain management. Using mixed methods, we aimed to understand how and why some rural adults use cannabis for pain, including within the context of co-use with opioids. Participants (N = 14, Oklahoma) were rural-dwelling adults who used tobacco and ≥1 other substance, including cannabis and opioids, ≥3 days per week. Participants completed 14 days of ecological momentary assessment (EMA) regarding substance use and subsequent in-depth interviews discussing maps of their substance use reports. Half (7/14) described cannabis use for chronic pain, and most of these (85%) reported use on ≥75% of EMA days. The most frequently reported cannabis use motive was therapeutic/medicinal (90% of use reports). Most reports were of combusted cannabis (88% of use reports) at home (99% of use reports). Same-day use of cannabis and opioids was relatively common (45% of daily surveys), but seemingly not within close temporal proximity. Interview narratives characterized cannabis as modifying pain-adjacent factors (eg, thoughts), not eliminating pain itself. They recounted using a repertoire of substances to manage different pain dimensions (eg, intensity, quality) and balance perceived trade-offs of different substances. Participants described high medical cannabis access, low pain specialist access, and most physicians as unwilling to discuss cannabis for pain. The findings suggest that rural-dwelling patients could benefit from increased access to comprehensive pain management, having cannabis addressed within pain management provider discussions, and that risks and benefits of cannabis use for pain must be better established. PERSPECTIVE: This study used a geographically explicit EMA mixed method to gather rich, intensive pilot data on cannabis use and co-use for chronic pain in rural Oklahoma. It provides unique insights to inform future research on cannabis use among a vulnerable and understudied subgroup of adults with pain-rural residents.

The Relation Between Travel Distance and Overall Survival for HPV-Associated Cancers in a High-Burden State.

Purpose: To assess the association between travel distance to an academic health system and overall survival for patients with human papillomavirus (HPV)-associated cancers. Methods: Using hospital-based cancer registry data from 2005-2019, we calculated unidirectional travel distance from each patient's geocoded address to our academic health center through network analysis. We categorized distance as short (<25 miles), intermediate (25-74.9 miles), or long (≥75 miles). The primary outcome was time from the date of initial diagnosis to the date of death or last contact. We used multivariable Cox proportional hazards regression to evaluate the association between travel distance and overall survival. We also estimated the adjusted observed 5-year survival rate. Results: Patients with HPV-associated cancers traveling distances that were intermediate (hazard ratio [HR], 1.23; 95% CI, 1.06-1.43) and long (HR, 1.15; 95% CI, 1.01-1.32) had a higher hazard of death than the short-distance group. The adjusted 5-year observed survival rates for HPV-associated cancers were lowest in the intermediate-distance group (60.4%) compared with the long-(62.6%) and short-distance (66.2%) groups. Conclusions: Our findings indicate that travel distance to an academic health center was associated with overall survival for patients with HPV-associated cancers, reflecting the importance of considering travel burden in improving patient outcomes.

BCR/ABL activates mdm2 mRNA translation via the La antigen.

In a BCR/ABL-expressing myeloid precursor cell line, p53 levels were markedly downmodulated. Expression of MDM2, the negative regulator of p53, was upregulated in a tyrosine kinase-dependent manner in growth factor-independent BCR/ABL-expressing cells, and in accelerated phase and blast crisis CML samples. Increased MDM2 expression was associated with enhanced mdm2 mRNA translation, which required the interaction of the La antigen with mdm2 5' UTR. Expression of MDM2 correlated with that of La and was suppressed by La siRNAs and by a dominant negative La mutant, which also enhanced the susceptibility to drug-induced apoptosis of BCR/ABL-transformed cells. By contrast, La overexpression led to increased MDM2 levels and enhanced resistance to apoptosis. Thus, La-dependent activation of mdm2 translation might represent an important molecular mechanism involved in BCR/ABL leukemogenesis.

Meta-analysis Analyzing the Effect of Therapies on 6-Minute Walk Distance in Heart Failure With Reduced Ejection Fraction.

The 6-minute walk distance (6MWD) carries prognostic value in patients with heart failure with reduced ejection fraction (HFrEF). We performed this systematic review and meta-analysis to evaluate the effect of heart failure therapies on improvement in 6MWD. A systematic search of MEDLINE and Embase was conducted for randomized controlled trials measuring 6MWD at baseline and at follow-up in at least 50 patients with HFrEF across both arms. The primary outcome was improvement in 6MWD at follow-up. Meta-analysis was stratified in groups on the basis of medical therapy, device-based therapy, autonomic modulation, and exercise. Mean differences (MDs) with 95% confidence interval (CI) were reported across multiple studies that were included in the meta-analysis. A total of 44 studies met the inclusion criteria for systematic review; 17 of which were included for meta-analysis. Statistical analysis showed a statistically significant improvement in 6MWD in meters (m) at follow-up for device-based therapy (MD 20.01 m, 95% CI 18.71 to 21.31), autonomic modulation (MD 76.64 m, 95% CI 54.10 to 99.19), and exercise group (MD 39.52 m, 95% CI 19.68 to 59.35). Pooled analysis of medical therapy did not show statistically significant improvement in 6MWD at follow-up (MD 31.69 m, 95% CI -6.52 to 69.91). Device-based therapy (cardiac resynchronization therapy and cardiac contractility modulation), autonomic modulation, and exercise training programs are associated with improvement in 6MWD in patients with HFrEF. 6MWD is a useful test to gauge improvement in functional capacity among patients with HFrEF, especially those with severe symptomatic heart failure.

Cancer-associated venous thromboembolism: Incidence and features in a racially diverse population.

BACKGROUND: Data on the population-based incidence of cancer-associated venous thromboembolism (VTE) from racially diverse populations are limited. OBJECTIVE: To evaluate the incidence and burden of cancer-associated VTE, including demographic and racial subgroups in the general population of Oklahoma County-which closely mirrors the United States. DESIGN: A population-based prospective study. SETTING: We conducted surveillance of VTE at tertiary care facilities and outpatient clinics in Oklahoma County, Oklahoma, from 2012-2014. Surveillance included reviewing all imaging reports used to diagnose VTE and identifying VTE events from hospital discharge data and death certificates. Cancer status was determined by linkage to the Oklahoma Central Cancer Registry. MEASUREMENTS: We used Poisson regression to calculate crude and age-adjusted incidence rates of cancer-associated VTE per 100 000 general population per year, with 95% confidence intervals (95% CI). RESULTS: The age-adjusted incidence (95% CI) of cancer-associated VTE among adults age ≥ 18 was 70.0 (65.1-75.3). The age-adjusted incidence rates (95% CI) were 85.9 (72.7-101.6) for non-Hispanic Blacks, 79.5 (13.2-86.5) for non-Hispanic Whites, 18.8 (8.9-39.4) for Native Americans, 15.6 (7.0-34.8) for Asian/Pacific Islanders, and 15.2 (9.2-25.1) for Hispanics. Recurrent VTE up to 2 years after the initial diagnosis occurred in 38 of 304 patients (12.5%) with active cancer and in 34 of 424 patients (8.0%) with a history of cancer > 6 months previously. CONCLUSION: Age-adjusted incidence rates of cancer-associated VTE vary substantially by race and ethnicity. The relatively high incidence rates of first VTE and of recurrence warrant further assessment of strategies to prevent VTE among cancer patients.

Factors associated with low-dose CT lung cancer screening participation in a high burden state: Results from the 2017-2018 BRFSS.

INTRODUCTION: The purpose of this study was to examine low-dose computed tomography (LDCT) for lung cancer screening (LCS) eligibility, utilization, and factors associated with self-reported participation among eligible individuals. METHODS: Data from the 2017 and 2018 Oklahoma Behavioral Risk Factor Surveillance System (BRFSS) were used and analysis was restricted to data from individuals eligible for screening based on the US Preventive Services Task Force (USPSTF) guidelines. Analyses using recursive partitioning and weighted logistic regression were conducted from November 2019 to March 2020. The final study sample consisted of 596 respondents. RESULTS: Only 10.84 % of participants reported LCS participation. Differences in participation by sex were observed. Among males, those with COPD were more likely to report participating in screening. Among females, those who self-reported their health status as "fair or worse" were more likely to participate in LCS. CONCLUSION: Rates of utilization were higher in this study than in earlier estimates; however, utilization of LCS remains suboptimal. Although LCS participation rates were similar for males and females, differences were observed by sex. Opportunities exist to increase screening participation among eligible individuals, and findings from this study can be used for program planning such as patient engagement resources and effective clinical decision support. POLICY STATEMENT: This study further demonstrates the complex nature of cancer screening participation, specifically LDCT LCS. Under the current USPSTF guidelines only a small proportion of the population is considered eligible thus to prevent lung cancer mortality, the eligibility criteria regarding smoking history and screening age may need to be reevaluated. Furthermore, this study adds to the evidence that strategies to increase screening participation among eligible individuals may need to differ by sex.

Management of Aneurysmal Subarachnoid Hemorrhage: Variation in Clinical Practice and Unmet Need for Follow-up among Survivors-A Single-Center Perspective.

OBJECTIVE: The purpose of the present study is to investigate the existence and/or prevalence of clinical practice variation in management of aneurysmal subarachnoid hemorrhage (aSAH) and to determine the need for long-term follow-up. METHODS: A single-center study was carried out of patients with aSAH over a 5-year period divided into 2 halves (2.5 years each) before and after addition of a dually trained cerebrovascular neurosurgeon. In-hospital clinical practice, clinical outcome (mortality and discharge destination) and long-term outcome (modified Rankin Scale score and Telephone Interview for Cognitive Status [TICS]) were compared using descriptive summaries and nonparametric tests. RESULTS: Among 251 patients admitted with aSAH, 115 (45.8%) were before the index event, whereas 136 (54.2%) were during the later period. The aneurysm-securing procedure changed from coil embolization to clip ligation (12/115 [10.4%] vs. 84/136 [61.8%]; P < 0.0001) during the latter years. Interventional treatment for cerebral vasospasm has decreased (58/115 [50.4%] vs. 49/136 [36.0%]; P = 0.0002). Patients surviving hospitalization had more clinic follow-up after discharge during the latter period (42/85 [49.4%] vs. 76/105 [72.4%]; P = 0.0012) and ventriculoperitoneal shunt placement for delayed hydrocephalus (1/85 [1.2%] vs. 9/105 [8.6%]; P = 0.02). A subcohort of aSAH survivors (n = 46) had lower median TICS score during the earlier study period (31.5 [interquartile range, 22-36] vs. 33 [interquartile range, 27-38]; P = 0.038). Similarly, preictal smoking status and hyperlipidemia were associated with adverse TICS score in a multivariate model (P = 0.007). CONCLUSIONS: Postdischarge clinical follow-up has improved facilitating recognition and treatment of delayed hydrocephalus. Existence of cognitive deficits among survivors calls for establishment of multidisciplinary clinics for long-term management of aSAH.

Systemic response of coated-platelet and peripheral blood inflammatory cell indices after aneurysmal subarachnoid hemorrhage and long-term clinical outcome.

PURPOSE: Post-hemorrhage period after aneurysmal subarachnoid hemorrhage (aSAH) has several systemic manifestations including prothrombotic and pro-inflammatory states. Inter-relationship between these states using established/routine laboratory biomarkers and its long-term effect on clinical outcome is not well-defined. MATERIALS AND METHODS: Retrospective analysis of prospective cohort of 44 aSAH patients. Trend of procoagulant biomarkers [coated-platelets, mean platelet volume to platelet count (MPV:PLT)] and peripheral inflammatory biomarkers [platelet-lymphocyte ratio (PLR), neutrophil-platelet ratio (NLR)] were analyzed using regression analysis. Occurrence of delayed cerebral ischemia (DCI), modified Rankin score (mRS) of 3-6 and Montreal cognitive assessment (MoCA) of <26 at 1-year defined adverse clinical outcome. RESULTS: Patients with worse mRS and MoCA score had higher rise in coated-platelet compared to those with better scores [20.4 (IQR: 15.6, 32.9) vs. 10.95 (IQR: 6.1, 18.9), p = 0.003] and [16.9 (IQR: 13.4, 28.1) vs. 10.95 (IQR: 6.35, 18.65), p = 0.02] respectively. NLR and PLR trends showed significant initial decline followed by a gradual rise in NLR among those without DCI as compared to persistent low levels in those developing DCI (0.13 units/day vs. -0.07 units/day, p = 0.06). CONCLUSIONS: Coated-platelet rise after aSAH is associated with adverse long-term clinical outcome. NLR and PLR trends show an early immune-depressed state after aSAH.

Using synthetic precursor and inhibitor miRNAs to understand miRNA function.

Although the majority of gene function studies center themselves around protein-encoding RNAs, the study of non-protein-encoding RNAs is becoming more widespread because of the discovery of hundreds of small RNA termed micro (mi) RNA that have regulator functions within cells. Currently, over 470 human miRNA genes are predicted to exist and are annotated within the "miRBase" public miRNA database ( http://microrna.sanger.ac.uk/ ). There is no denying that short interfering (si) and short hairpin (sh) RNAs have revolutionized how scientists approach understanding gene function; however, si and shRNAs are not effective for analyzing the function of miRNAs given that miRNAs are typically short (17-24 bases). In turn, new sets of agents that allow for the expression of miRNA above endogenous levels and inhibition of miRNAs have become a valuable technology for the study of these small regulatory RNAs. In this chapter, we provide step-by-step methods on how to utilize synthetic precursor and antisense inhibitor molecules for understanding miRNA function.

A step-by-step procedure to analyze the efficacy of siRNA using real-time PCR.

Knockdown of cellular RNA using short interfering RNA has enabled researchers to perform loss-of-function (LOF) experiments in a wide variety of cell types and model systems. RNA interference techniques and reagents have made possible experiments that test everything from the analysis of function of single genes to screening for genes that are involved in critical biological pathways on a genome-wide scale. Although siRNA experiments are generally common practice in research laboratories, it is still important to keep in mind that many factors can influence efficacy of knockdown. A properly designed siRNA, optimized protocols of siRNA delivery, and an appropriate and well-optimized readout are all critical parameters for ensuring the success of your experiment. In this chapter, we provide step-by-step procedures for performing an siRNA knockdown experiment from cell culture to analysis of knockdown using quantitative real-time PCR.

Trends of Platelet Volume Index Predicts Delayed Cerebral Ischemia After Subarachnoid Hemorrhage.

BACKGROUND: Delayed cerebral ischemia (DCI) is a major cause of disability after aneurysmal subarachnoid hemorrhage (aSAH). Activated platelets are surrogate markers for DCI occurrence and are reliably represented by mean platelet volume (MPV) to platelet count (PLT) ratio. If validated as a predictor of DCI, the ratio will allow clinicians to use it as a readily available tool in patient management. METHODS: Retrospective analysis of aSAH patient database at a tertiary care hospital. MPV:PLT ratio was defined as (MPV value(fL)PLT per 1000∗100). Nonlinear regression estimated differences in the ratio's pattern of change over time between those with or without DCI. Receiver operating characteristic curve determined optimal threshold of rise in MPV:PLT ratio to predict DCI. RESULTS: Average age of the cohort (n = 169) was 53.0 ± 13.0 years, and 38 patients (22.5%) developed DCI. Nonlinear regression analysis detected a transition of rising and declining MPV:PLT ratio at 3 days after aSAH. Rate of rise in MPV:PLT ratio was 0.5 units/day (95% confidence interval 0.3-0.7) in patients developing DCI as compared with 0.2 units/day (95% confidence interval 0.1-0.3) in those without DCI (P = 0.0004). Receiver operating characteristic analysis determined a threshold of 0.33 units/day rise in MPV:PLT predicted DCI with 89.5% sensitivity and 90.8% specificity. Patients who died demonstrated a steeper rise during the first 3 days (0.29 units/day) than those who were discharged home (0.21 units/day) (P = 0.004). CONCLUSIONS: Trend of MPV:PLT ratio after aSAH predicts DCI. This association alludes to significant early rise in reactive platelet population after aSAH in patients developing DCI.

Radiological Estimation of Intracranial Blood Volume and Occurrence of Hydrocephalus Determines Stress-Induced Hyperglycemia After Aneurysmal Subarachnoid Hemorrhage.

Acute phase after aneurysmal subarachnoid hemorrhage (aSAH) is associated with several metabolic derangements including stress-induced hyperglycemia (SIH). The present study is designed to identify objective radiological determinants for SIH to better understand its contributory role in clinical outcomes after aSAH. A computer-aided detection tool was used to segment admission computed tomography (CT) images of aSAH patients to estimate intracranial blood and cerebrospinal fluid volumes. Modified Graeb score (mGS) was used as a semi-quantitative measure to estimate degree of hydrocephalus. The relationship between glycemic gap (GG) determined SIH, mGS, and estimated intracranial blood and cerebrospinal fluid volumes were evaluated using linear regression. Ninety-four [94/187 (50.3%)] among the study cohort had SIH (defined as GG > 26.7 mg/dl). Patients with SIH had 14.3 ml/1000 ml more intracranial blood volume as compared to those without SIH [39.6 ml (95% confidence interval, CI, 33.6 to 45.5) vs. 25.3 ml (95% CI 20.6 to 29.9), p = 0.0002]. Linear regression analysis of mGS with GG showed each unit increase in mGS resulted in 1.2 mg/dl increase in GG [p = 0.002]. Patients with SIH had higher mGS [median 4.0, interquartile range, IQR 2.0-7.0] as compared to those without SIH [median 2.0, IQR 0.0-6.0], p = 0.002. Patients with third ventricular blood on admission CT scan were more likely to develop SIH [67/118 (56.8%) vs. 27/69 (39.1%), p = 0.023]. Hence, the present study, using unbiased SIH definition and objective CT scan parameters, reports "dose-dependent" radiological features resulting in SIH. Such findings allude to a brain injury-stress response-neuroendocrine axis in etiopathogenesis of SIH.

Coated-Platelet Trends Predict Short-Term Clinical OutcomeAfter Subarachnoid Hemorrhage.

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high socio-economic burden. Prothrombotic states of early brain injury (EBI) and delayed cerebral ischemia (DCI) after aSAH determine morbidity and mortality. To understand how activated platelets might contribute to such prothrombotic states, we studied trends in coated-platelets during EBI and DCI periods. Serial blood samples from a prospective cohort of aSAH patients were collected and assayed for coated-platelet levels. Patient's coated-platelet level during post-hospital discharge follow-up served as an estimate of baseline. Occurrence of DCI, Montreal cognitive assessment (MOCA) score of < 26, and modified Rankin scale (mRS) of 3-6 were considered poor clinical outcomes. Non-linear regression analysis detected a transition between periods of rising and declining coated-platelet levels at day 4. Additional regression analyses of coated-platelet trends before day 4 showed differences among patients with modified Fisher 3-4 [4.2% per day (95% CI 2.4, 6.1) vs. - 0.8% per day (95% CI - 3.4, 1.8); p = 0.0023] and those developing DCI [4.6% per day (95% CI 2.8, 6.5) vs. - 1.9% per day (95% CI - 4.5, 0.5); p < 0.001]. Differences between peak coated-platelet levels and baseline levels were larger, on average for those with DCI [18.1 ± 9.6 vs. 10.6 ± 8.0; p = 0.03], MOCA < 26 [17.0 ± 7.8 vs. 10.7 ± 7.4; p = 0.05] and mRS 3-6 [24.8 ± 10.5 vs. 11.9 ± 7.6; p = 0.01]. Coated-platelet trends after aSAH predict DCI and short-term clinical outcomes. The degree of rise in coated-platelets is also associated with adverse clinical outcomes.

Antisense inhibition of human miRNAs and indications for an involvement of miRNA in cell growth and apoptosis.

Of the over 200 identified mammalian microRNAs (miRNAs), only a few have known biological activity. To gain a better understanding of the role that miRNAs play in specific cellular pathways, we utilized antisense molecules to inhibit miRNA activity. We used miRNA inhibitors targeting miR-23, 21, 15a, 16 and 19a to test efficacy of antisense molecules in reducing miRNA activity on reporter genes bearing miRNA-binding sites. The miRNA inhibitors de-repressed reporter gene activity when a miRNA-binding site was cloned into its 3'-untranslated region. We employed a library of miRNA inhibitors to screen for miRNA involved in cell growth and apoptosis. In HeLa cells, we found that inhibition of miR-95, 124, 125, 133, 134, 144, 150, 152, 187, 190, 191, 192, 193, 204, 211, 218, 220, 296 and 299 caused a decrease in cell growth and that inhibition of miR-21 and miR-24 had a profound increase in cell growth. On the other hand, inhibition of miR-7, 19a, 23, 24, 134, 140, 150, 192 and 193 down-regulated cell growth, and miR-107, 132, 155, 181, 191, 194, 203, 215 and 301 increased cell growth in lung carcinoma cells, A549. We also identified miRNA that when inhibited increased the level of apoptosis (miR-1d, 7, 148, 204, 210, 216 and 296) and one miRNA that decreased apoptosis (miR-214) in HeLa cells. From these screens, we conclude that miRNA-mediated regulation has a complexity of cellular outcomes and that miRNAs can be mediators of regulation of cell growth and apoptosis pathways.

Ku protein targeting by Ku70 small interfering RNA enhances human cancer cell response to topoisomerase II inhibitor and gamma radiation.

Ku protein is a heterodimer (Ku70 and Ku86) known to play an important role in V(D)J recombination, apoptosis, telomere fusion, and double-strand break repair. Its role in double-strand breaks is relevant to cancer therapy because lack of Ku86 causes one of the most radiation-responsive phenotypes (hamster cells, XRS5). Although it is known that the heterodimer is necessary for the various functions of this protein, the impact of targeting Ku in human cancer cells has not been shown due to lack of appropriate approaches. It is also not known whether complete knock-out of Ku protein is required to enhance the sensitivity of human cells to gamma radiation as Ku protein is much more abundant in human cells than in hamster cells. In the current article, we have investigated the direct effect of Ku70 depletion in human cervical epithelioid (HeLa) and colon carcinoma (HCT116) cells. We specifically targeted Ku70 mRNA by use of small interfering RNA (siRNA). Of the five Ku70 siRNA synthesized, three inhibited the expression of Ku70 by up to 70% in HeLa cells. We have tested the effect of chemically synthesized siRNAs for target sequence 5 (CS #5) on the response of HeLa cells 72 hours after transfection to gamma radiation and etoposide, as this showed the maximum inhibition of Ku70 expression. Ku70 siRNA induced a decrease in the surviving fraction of irradiated HeLa cells by severalfold. Similar sensitizing effects were observed for etoposide, a topoisomerase II inhibitor. Studies with HCT116 cells using the same Ku70 siRNA (CS #5) showed a direct correlation between expression of Ku70 and sensitization to radiation and etoposide treatments.

A model for heterogeneous nuclear ribonucleoproteins in telomere and telomerase regulation.

The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a large family of nucleic acid binding proteins that are often found in, but not restricted to, the 40S-ribonucleoprotein particle. Subsets of hnRNPs are strictly nuclear while others shuttle between the nucleus and cytoplasm. Members of the hnRNP family have been implicated to have roles in many aspects of mRNA maturation/turnover and in telomere and telomerase regulation. Telomeres are repetitive DNA elements mainly found at the ends of human chromosomes. In most normal cells, telomeres shorten with each cell division. Telomere shortening can be compensated for by a ribonucleoprotein complex, called telomerase. Telomerase, consisting of an integral RNA and catalytic protein component as well as several auxiliary factors, extends the 3'-G-rich strand of the ends of the telomeres. Here we present new data and describe a model that implicates the telomerase bound hnRNPs in promoting telomere access by interacting with telomeres. Telomere bound hnRNPs include hnRNP A1, A2-B1, D and E and telomerase bound hnRNPs including hnRNPA1 C1/C2 and D. The telomere and telomerase bound hnRNPs may prove to be good targets for regulating telomere length.

c-Myc controls proliferation versus differentiation in human pancreatic endocrine cells.

Using immortalized human pancreatic endocrine cell lines, we have shown previously that differentiation into hormone-expressing cells requires cell-cell contact acting in synergy with the homeodomain transcription factor pancreatic duodenal homeobox-1 (PDX-1). Although differentiation is associated with a decrease in cell proliferation, the mechanisms behind this relationship are not known. Using TRM-6, a delta cell line, and betalox5, a beta-cell line, we show here that cell-cell contact and subsequent endocrine differentiation lead to a down-regulation of the c-myc protooncogene. Overexpression of c-Myc obtained with an inducible c-Myc-estrogen receptor fusion protein results in an increase in cell proliferation and the ablation of hormone expression. Moreover, we show that although c-Myc is expressed in a subset of cells from the human fetal and adult pancreas, it is absent in differentiated endocrine cells. The mechanism by which c-Myc interferes with hormone expression may be through effects on the homeodomain transcription factor PDX-1, as immunostaining for PDX-1 in cells with activated c-Myc revealed a redistribution of PDX-1 from the nucleus to the cytoplasm. These results suggest that c-Myc plays a central role in a cell-cell contact-mediated switch mechanism by which cell division vs. differentiation in endocrine cells is determined.

Antibody targeted siRNA delivery.

It is very clear that RNA interference (RNAi) is a potent and versatile tool for gene silencing. One of the hurdles to making siRNA/miRNA a human therapeutic includes effective in vivo delivery and being able to deliver drugs to target cells only. The commercial success of in vivo applications of RNAi hinges on the development of new delivery methods. Our strategy involves the use of antibody-based delivery agents to target and deliver siRNA into specific cell types. We have developed antibody-based agents for directed delivery into cultured cells and animal disease models. Using antibodies against various cell surface receptors, modified siRNAs are attached to antibody complexes using RNA carrier proteins. The complex can then be intravenously administered to in vivo models and taken up by specific cells via receptor-mediated endocytosis. The labile structure of the linking agents enables release of siRNA molecules post internalization. Using this targeting strategy, we have developed a method that allows any commercially available or recombinant antibody to be conjugated to siRNA for delivery purposes.

Delivery of RNAi mediators.

Delivering polynucleotides into animals has been a major challenge facing their success as therapeutic agents. Given the matured understanding of antibody-mediated delivery techniques, it is possible to rationally design delivery vehicles that circulate in the blood stream and are specifically delivered into target organs. If the targeting moiety is designed to contain the cargo of an RNAi mediator without impacting its paratope, directed delivery can be achieved. In this article, we review the state of art in delivery technology for RNA mediators and address how this technique could soon be used to enhance the efficacy of the numerous small RNA therapeutic programs currently under evaluation.