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A Subject Specific Surface Electromyography Model For Estimating L4/L5 Compressive Loading
Get PDFIntroduction: Low Back Pain (LBP) is a leading cause of activity limitation worldwide and results in 149 million lost work days annually in the United States. The total costs of LBP are estimated to be 200 billion annually. Specific causes of LBP account for less than 15% of LBP cases. Heavy loading of the lumbar spine and tight hamstrings have been identified as risk factors for LBP. Tight hamstrings pull the pelvis posteriorly and reduce the lordosis of the spine, resulting in increased loading of the lumbar vertebral bodies of the spine. While this mechanism has been described, a link between hamstring stretching and reduced lumbar vertebral body loading has not been established. Development of an objective method to measure lumbar loading would assist is determining a link between tight hamstrings and lumbar loading. Electromyography (EMG) modeling is a non-invasive tool shown to report physiologically appropriate lumbar loading. In this thesis I developed a non-invasive EMG model to measure L4/5 compressive loading and applied the model to measure differences in L4/5 compressive loading before and after a six-week hamstring stretching program. Background: Instrumented Vertebral Body Replacements (VBR), as well as Biomechanical and EMG modeling have all been previously reported as methods to determine spinal lumbar loads. VBR is useful for measuring loads in vivo, but cannot be used for healthy subject populations. Biomechanical modeling using inverse dynamics has been shown to report physiologically accurate values, but may not match underlying muscle activity. Electromyography modeling reports physiological compressive loading, but currently makes use of a single gain value relating muscle force to EMG muscle activity, assuming a linear relationship for all subjects. Muscle force to EMG relationships previously revealed non-linear relationships and high percent error values for general relationships. In this thesis, I attempted to develop a patient specific EMG model for measuring L4/L5 compressive loading. I hypothesize that use of a subject specific muscle force to EMG relationships will reduce percent error of muscle force estimation. Methods: Ten volunteer subjects with tight hamstrings and no history of back injury were recruited. EMG’s were placed on six major trunk muscles. Subjects completed 3 isokinetic voluntary contraction trials (VCT) at 30 and 60°/sec. After addition of 53 reflective markers on key anatomical landmarks, subjects performed a series of tasks including straight leg stoop lifting (SLSL). All testing was repeated after a six week stretching protocol. VCT trials and EMG data was used to build subject specific and general relationships for each muscle. Subject specific relationships were used to calculate compressive lumbar loading during SLSL trials. Compressive loading calculated using an AnyBody lower body model and from three subjects from VBR provided by Orthoload were used for comparing models. Compressive loading values before and after the six week stretching protocol were also compared by both AnyBody and the EMG model to determine the effects of hamstring stretching. Results: Subject specific relationships showed a decreased percent error in estimating muscle forces compared to general relationships. The EMG model appeared to vary in loading estimations more than both Orthoload and AnyBody, though most subjects fell within an appropriate range. Same day intra-subject variability testing showed a small difference in impulse measurements between testing sessions. The AnyBody lower body model consistently reported lower loading than both Orthoload and the EMG model. Neither the AnyBody model nor the EMG model found any differences in compressive loading when comparing pre and post hamstring stretching. Discussion: Our model is an initial step in the development of a patient specific EMG model. Inclusion of additional muscles and accounting for antagonist muscle activity during VCT trials would improve the accuracy of our model and are potential next steps. Lack of differences in pre and post hamstring stretching implies that total compressive loading across the L4/L5 disk pre and post hamstring stretching does not change, though it’s possible the distribution of the load on the disc changes
Medication Nonadherence, Health Care Utilization, and SafeMed Care Transitions Model Impact in Super-Utilizers
Get PDFBACKGROUND: Super-utilizers are individuals with disproportionately high inpatient and emergency department (ED) use, and mostly have multiple chronic conditions and use multiple concurrent medications. They place a substantial burden on the U.S. healthcare system and have become the focus of policy initiatives aimed at reducing their disproportionate inpatient and ED use. Medication management is critical for these patients since nonadherence to essential chronic medications is associated with poor health outcomes, and higher health care utilization and costs. OBJECTIVES: This dissertation employed a three empirical research papers approach to study the following aims: (1) the prevalence and patterns of medication nonadherence to essential chronic medications in Medicare super-utilizers with chronic conditions, and to identify the factors associated with medication nonadherence, with special emphasis on factors including mental illness and use of opioid medications, (2) examine associations between medication nonadherence, and inpatient and ED use, and to evaluate other risk factors associated with health care utilization in Medicare super-utilizers with chronic conditions, and (3) examine the impact of the SafeMed Program, a care transitions program with a focus on medication management, on medication use and adherence among publicly insured super-utilizers with chronic conditions. METHODS: This dissertation was based on patients eligible for the SafeMed Program, a care transitions program with a focus on medication management. The SafeMed Program targeted publicly insured super-utilizers with chronic conditions who were admitted to three hospitals that were part of a non-profit hospital system in Memphis, TN. The study sample included Medicare or TennCare insured adults who met the SafeMed Program eligibility criteria, had continuous medication coverage, and filled at least one of the drug classes used to treat hypertension, congestive heart failure, coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), or asthma. Papers 1 and 2 were retrospective panel data analyses of the 2-year baseline data for Medicare Part D beneficiaries meeting the SafeMed Program eligibility criteria. Association between various factors and medication nonadherence was examined using random effects models with a binary distribution. Association between medication nonadherence and inpatient and ED utilization was examined using fixed effects negative binomial analyses. Paper 3 used a prospective quasi-experimental study design to examine the effectiveness of the SafeMed Program on medication use and adherence among SafeMed participants compared with patients in a control group using a difference in differences (DID) approach. RESULTS: Paper 1 demonstrated that the proportion of patients who were nonadherent to their essential chronic disease medications ranged from 45.7% to 58.4%, with the highest rate for COPD/Asthma medications (54.3% to 64.4%). In the multivariate analysis examining predictors of medication nonadherence, we found that compared with patients who did not use any opioid medication in the previous period, patients using \u3e4 opioid medications had higher odds of medication nonadherence. Other risk factors for nonadherence included age \u3c65 \u3eyears, dual beneficiaries receiving low income subsidy, and higher number of unique prescribers. Factors associated with lower odds of nonadherence included number of different medications filled and \u3e1 physician office visits in the previous period. When examining the associations between medication nonadherence, and inpatient and ED use in Paper 2, we found that among elderly Medicare beneficiaries, nonadherence was significantly associated with a 57% increase in inpatient hospitalizations, and among non-elderly Medicare beneficiaries, nonadherence was significantly associated with 41% increase in inpatient stays and 25% increase in ED visits. Similar associations were found across all therapy classes examined (diabetes, cardiovascular, and COPD/asthma) in both age groups. However, nonadherence to diabetes and COPD/asthma drugs was not significantly associated with ED visits. Among other factors, mental illness, substance use disorder, non-Hispanic blacks and dual low-income subsidy status were associated with higher inpatient and ED use. Finally, the DID analyses in paper 3 showed that SafeMed Program did not improve medication adherence in vulnerable super-utilizers with chronic conditions. However, for some sub-group populations including Medicare only beneficiaries, patients \u3e65 years of age, and patients with lower number of comorbidities, the intervention may have ensured that the decline in the probability of being adherent was not as low as it would have been in the absence of the intervention. Additionally, for patients diagnosed with COPD/asthma and diabetes, there were positive medication use trends in favor of enrollees, however, these associations were not statistically significant. CONCLUSIONS: This study is the first to our knowledge to demonstrate the magnitude and importance of medication nonadherence in vulnerable super-utilizers with chronic conditions. The study findings show that medication nonadherence is a significant problem among super-utilizers with chronic conditions and is associated with high inpatient and ED utilization. Furthermore, the findings suggest that medication management interventions during care transitions may not be sufficient for these high-risk patients and other alternative strategies such as addressing social risk factors, and removing cost barriers may be needed to improve adherence, especially among low-income dual beneficiaries, Medicaid enrollees, and patients with higher comorbidity
Investigating the Regulation and Function of the NR4A Nuclear Receptors in Cancer
Get PDFThe nuclear receptor (NR) superfamily represents a structurally-conserved group of ligand-regulated transcription factors. These proteins have critical roles in various physiological and pathological processes, including cancer, and have been targets of drug therapy. The orphan NR subfamily 4A (NR4A), which includes the NR4A1 (Nur77), NR4A2 (Nurr1), and NR4A3 (Nor-1) genes, has been implicated in adult solid tumors and has been characterized as pro-tumorigenic mediator of cell proliferation, transformation, migration, and drug resistance. Alternatively, in leukemia, NR4A1 and NR4A3 have been described as tumor suppressors in hematologic malignancies. Members of the NR4A family are commonly overexpressed in cancer and this has been attributed to their regulation by other oncogenic signaling pathways.
Despite the understanding of signaling cascades that lead to overexpression of the NR4A members, little is known about their regulation by microRNAs (miRNAs). miRNAs are small, non-coding, endogenous RNAs that are transcribed, processed, and used to direct cellular proteins that destabilize or block translation of target mRNA. In this study, we first sought to determine the miRNAs that are responsible for regulating NR4A2. Using a 3ʹ UTR reporter assay, we identified miR-34 as a regulator of the NR4A2 through its 3ʹ UTR, which was confirmed using mutagenesis of the predicted binding region of the miR-34 seed region to its target site. We demonstrated that overexpression of exogenous or induction of endogenous miR-34 expression downstream of p53 activation by Nutlin-3a was associated with decreased endogenous NR4A2. Additionally, overexpression of NR4A2 was capable of suppressing the activation of p53 target genes, and was also able to attenuate the sensitivity of cells to the anti-proliferative effect of Nutlin-3a.
We further explored the roles of the NR4A family in pediatric cancer, an area that has not been fully investigated. We first determined that the members of the NR4A family are overexpressed in rhabdomyosarcoma (RMS) cell lines compared to normal muscle cells. Knockdown of NR4A1 or NR4A2 led to a reduction in cell proliferation and transformation, while knockdown of NR4A2 could also affect cell migration. Using a microarray approach, we sought to investigate the transcriptome-level changes in response to NR4A knockdown, and determined that knockdown of NR4A2 led to a unique gene signature, while NR4A1 and NR4A3 knockdown had large overlaps in expression changes. These unique gene expression changes in response to NR4A2 knockdown could explain the unique effects that NR4A2 has on migration.
Overall, this study has discovered miR-34 as a novel regulator of NR4A2, and places NR4A2 in a potential feedback mechanism involving p53, miR-34, and NR4A2. This could indicate that NR4A2 mediates at least some of its pro-oncogenic effects through the inhibition of p53, which is relieved by p53 itself upon activation. Alternatively, NR4A2, is shown to have other roles in cancer progression, potentially through novel downstream target genes. These data may be used in understanding the effects of miR-34 replacement therapy, as this method of treatment is progressing through clinical trials, allowing us to understand the diverse regulator cascades being modulated
Novel Oncogenic Drivers in Pediatric Gliomagenesis
Get PDFPediatric high-grade gliomas (pHGGs), with a two-year survival rate of less than 20%, are some of the most aggressive human cancers. This dissertation begins with our analysis of 127 pHGGs, including brainstem (BS) and non-brainstem (NBS) tumors, from 118 patients using next-generation sequencing technologies. Nearly one-third of BS-HGGs, also known as diffuse intrinsic pontine gliomas (DIPGs), harbored somatic heterozygous missense mutations in ACVR1, coding for a receptor serine-threonine kinase involved in bone morphogenetic protein (BMP) signaling. These alterations led to gain-of-function as evidenced by increased phosphorylation of downstream targets in primary astrocytes and zebrafish embryo ventralization. Whole-genome sequencing and RNASeq revealed that nearly half of our cohort contained structural variants. We identified recurrent gene fusions preserving the kinase domain of the neurotrophin family of receptor tyrosine kinases (NTRK) including three novel fusions and two fusions previously described in other tumor types. NTRK fusion genes were identified in 40% of infant (\u3c3 years of age) NBS-HGGs, and 7% of pHGG overall. We also found that infants have significantly reduced mutation burdens when compared to pHGGs in older children, suggesting a small number of oncogenic mutations are required in infant tumors. These findings, coupled with the observation that infants have a better prognosis than non-infants, make infant NBS tumors a distinct subgroup of pHGG. NTRK gene fusions also occur in pediatric low-grade glioma (pLGG) and adult glioblastoma but are not as enriched as they are in infant NBS-HGG, and adult glioblastoma and non-infant pHGGs exhibit higher mutation rates than infant tumors. NTRK fusion genes are therefore gliomagenic drivers throughout various development settings; yet it appears as if gliomas driven by the same oncogenic lesion can vary in tumor phenotype as a function of contextual differences. With this in mind, we used genetically engineered mice with a NTRK gene fusion knock-in allele to generate HGG in vivo. Given that tumor is evident by early postnatal life (P5), this is, to our knowledge, the first report of a bona fide spontaneous pHGG model. The second part of this dissertation is the characterization of these tumors
The Role of Drak2 in T Cell Function and Autoimmunity
Get PDFThe immune system utilizes many regulatory mechanisms to limit immune responses and ensure that immune cells target foreign pathogens and not healthy cells of the body. However, some immune cells can escape these checkpoints and attack the body’s healthy cells, leading to tissue destruction and devastating autoimmune disorders. For example, multiple sclerosis (MS) occurs when immune cells attack the myelin sheath surrounding neurons of the central nervous system (CNS). Likewise, the destruction of pancreatic islet cells by dysregulated immune cells leads to type 1 diabetes (T1D). Remarkably, there are more than 80 types of autoimmune diseases. An estimated 50 million Americans suffer from autoimmune disease, and the prevalence continues to increase. These diseases are chronic and potentially life threatening, with associated healthcare costs estimated at $100 billion annually. Current therapies to limit autoimmune diseases often include immunosuppressant medications that also increase susceptibility to infections and tumors. Therefore, therapeutic treatments which specifically inhibit autoreactive immune cells, while sparing immune cells required for pathogen or tumor clearance would significantly improve treatment options.
Drak2, a serine-threonine kinase, expressed abundantly in T and B cells, is a negative regulator of T cell activation. However, unlike other negative regulators, Drak2 plays an important role in eliciting autoimmunity, rather than preventing it. This is demonstrated by the finding that Drak2-/- mice are resistant to autoimmune disease in mouse models of T1D and MS. This resistance is due to reduced accumulation of Drak2-/- autoreactive T cells in the pancreas and CNS compared to wildtype mice. The decreased accumulation of autoreactive T cells in the target organs of Drak2-/- mice is partly due to diminished survival. Interestingly, despite Drak2-/- T cells being more sensitive to death, pathogen clearance and tumor surveillance are maintained in Drak2-/- mice. Therefore, inhibiting Drak2 is a potential alternative therapeutic approach to inhibit autoreactive T cells without suppressing the entire immune system. Thus, there is major interest in identifying the mechanisms by which Drak2 inhibits autoimmunity. This dissertation discusses the current knowledge of Drak2, its role in autoimmunity, and its potential as an inhibitory target to treat disease.
We utilized several in vivo T cell adoptive transfer models to show that resistance to T1D was due to the absence of Drak2 in T cells rather than pancreatic β-cells, and that regulatory T cells (Tregs) were required to elicit resistance. Further analysis revealed that in the absence of Drak2, IL-2 signaling and Treg development increased and likely contributes to disease resistance. We also determined that Drak2 is not a negative regulator of TGF-β signaling in primary T cells, opposing a previous report. Thus it is unlikely that alterations in the TGF-β signaling pathway mediate autoimmune disease resistance in the absence of Drak2. Finally, to advance our understanding of how Drak2 contributes to T cell accumulation, and ultimately to T1D and MS, we established in vitro culture methods to recapitulate the survival defect observed in the absence of Drak2 in vivo. Interestingly, we discovered that Drak2 modifies the actin polymerization pathway either directly or indirectly, and that Drak2-/- T cells exhibited defects in cell cycle progression, proliferation, and other actin-mediated T cell functions that impair T cell accumulation. Together, these data highlight novel insights into the roles of Drak2 in T cell function and autoimmunity, and suggest that subtle changes within these diverse processes may cooperate to contribute to autoimmune disease resistance in the absence of Drak2
Role of Occludin in the Regulation of Epithelial Tight Junctions
Get PDFTight junctions (TJ) constitute the primary component of epithelial barrier function, a disruption of which is involved in the pathogenesis of many gastrointestinal, pulmonary and renal diseases. Occludin is the major transmembrane protein of TJ, a deletion of which leads to a complex phenotype including chronic inflammation in several epithelial tissues of occludin deficient mice and poor TJ integrity in epithelial cell lines. Its down regulation was seen in Crohn’s disease, tumors of the colon, brain, endometrium and breast cancer. Occludin is also known to be a target that enables Hepatitis C Virus infection and bacterial pathogenesis. But the specific function of occludin in TJ remains unknown. Numerous studies implicated that occludin phosphorylation plays a crucial role in TJ regulation. Based on our previous studies, we have identified a conserved phosphorylation hotspot in the C-terminal domain of occludin, called occludin regulatory motif (ORM), which has a potential to confer dynamic properties to occludin. The present study was designed to determine the function of ORM in TJ regulation. Stable, occludin-deficient MDCK cell line (OD-MDCK) that expresses wild type occludin (OclWT) or a deletion mutant occludin (OclDM) that lacked ORM were developed. Confocal imaging and immunoprecipitation analyses showed that absence of ORM does not prevent occludin localization and interaction with ZO-1 at TJ. However, FRAP analysis showed that mobile fraction of occludin is reduced by the absence of ORM, suggesting the role of ORM in occludin dynamics. Also, Ca2+ depletion-induced disruption of TJ, adherens junctions and cytoskeleton and barrier dysfunction were attenuated in the absence of ORM. Mutation anlaysis of ORM phosphosites Y 398, Y 402, T403 and T404, revealed that ORM-mediated phosphorylation events determine the dynamic properties of TJ. Then the role of ORM-mediated protein interactions in TJ modulation was investigated. A synthetic peptide analogous to occludin regulatory region (ORP), which enhanced TJ assembly and attenuated radiation-induced barrier dysfunction in Caco-2 cells, was used as bait to pull down proteins that interact with ORM. Proteomic analyses and pull down assays using ORP and GST tagged occludin C-terminus identified that MAP7 (an epithelial specific microtubule associated protein) interacts with ORM in a tyrosine phosphorylation-dependent mechanism. Furthermore, MAP7 binding to occludin in Caco-2 cells was elevated by treatment with osmotic stress or dextran sodium sulfate, both known to increase occludin Tyr-phosphorylation. These data demonstrated that MAP7 interacts with ORM and mediates occludin redistribution during TJ disruption. In conclusion ORM confers dynamic properties to TJ via its phosphorylation dependent protein-protein interactions. The findings in my project establish the functional significance of ORM in TJ dynamics and regulatory mechanisms associated with TJ modulation. Identification of proteins that interact with ORM provides new therapeutic targets in the treatment of diseases associated with occludin depletion and epithelial barrier dysfunction
Will Meaningful Use (MU) Improve Cancer Data Reporting?
Get PDFThe American Recover and Reinvestment Act directives supply the healthcare community with the improvement of technology across the nation through the Health Information Technology Economic and Clinical Health (HITECH) Act passed in 2009 by promoting healthcare technology. In order to reach the goal of an interoperability that supports reliable communication systems, certain individual technological objectives need to be addressed in particular, Meaningful Use (MU). Meaningful Use objectives contribute to interoperability, with potential outcomes that may increase accuracy and reduce time for reporting. This study will describe how cancer data reporting methods impacts data accuracy and turnaround time evolving around transitions supported by Meaningful Use . Data for this study will be collected and analyzed from the South Carolina Department of Health and Environmental Control Central Cancer Registry (SCCCR) 2013 reporting year for conventional methods (fax, mail, facility visits, facility\u27s VPN access, and data imported to SCCCR server), electronic laboratory reporting (ELR) 2013 cases, and cases from March 2015 – October 2016 period via automatic electronic reporting method . The outcome of this research will display the differences and similarities of SCCCR cancer data reporting
The Effect of Hamstring Lengthening on Pelvic Tilt and Lumbar Lordosis
Get PDFA direct correlation between hamstring tightness and severity of lower back pain (LBP) has been previously reported. Hamstring contraction creates knee flexion, hip extension and posterior pelvic tilt. Posterior pelvic tilt causes the lumbar spine to flatten (hypolordosis) which places pressure on the anterior structures of the spine, including the intervertebral disc. This increased pressure may predispose individuals to disc degeneration and associated pain. For this reason, hamstring stretching is often prescribed to alleviate LBP, however, the effect of hamstring lengthening on the kinematics of the lumbar spine and pelvis is not well understood. Accurate measurement of lumbar spine movement is difficult to obtain in a motion capture laboratory due to subtle differences in marker placement, tissue interface and distribution. Therefore, the purpose of this study was twofold. The first goal was to develop and validate a method that allows accurate comparison of LL measurements from different testing sessions. Secondly, we aimed to assess the effect of hamstring lengthening on anterior pelvic tilt (PT) and lumbar lordosis (LL) in healthy subjects during gait, sit to stand, forward bend, and picking up a ball from the floor. Two different methods were developed and tested to determine which provided the most accurate LL measure from motion lab data. First, the LL correction method was developed and tested by using EOS bi-planar X-Rays of twenty-one healthy subjects. Two scans were taken of each subject; the first standing normally, and the second wearing a spine altering orthotic. Anatomical LL measurements were taken from the sagittal radiograph and the SterEOS reconstructions of both scans. Marker based LL was also taken from the sagittal radiograph. The first method computed the ratio of the anatomical based measurement to marker based measurement to give a correction factor (CF). The second method computed the difference between the anatomical measurement and the marker based measurement to give a correction constant (CC). The CF and CC were then applied to marker based measurements from the second scan to give a corrected LL. The correction constant resulted in the lowest average error in corrected LL. The average error for this method was 3.2°±2.8° (Mean ± SD) which corresponding to a percent error of 6.2% ± 4.8%. This was found to have less error than the error introduced by inconsistent marker placement between trials, although the use of it is limited to activities with minimal lumbar flexion. Next, nine healthy individuals with tight hamstrings (popliteal angle greater than 25°) were recruited for this study. A physical therapist placed 58 reflective markers by palpation on anatomical landmarks of the torso and lower extremities. Subjects performed walking, sit to stand, forward bend, and ball pick up from the floor, while ten optoelectronic cameras recorded the 3D location of the reflective markers. Subjects were then scanned with the spine markers using an EOS bi-planar X-ray system. Following testing, participants completed a six week stretching program designed to increase hamstring length. All baseline testing was then repeated. PT was defined as the angle between horizontal and the line extending from the posterior superior iliac spine marker to the anterior superior iliac spine marker. LL was defined as the acute angle between the lines connecting the markers on T12 to L2 and S2 to L4. The LL correction constant was applied to walking and standing activities to give corrected LL values. The change in PT and corrected LL was then found for each participant. All subjects had a decrease in popliteal angle (-18.8°±11.6°). It was found that hamstring lengthening increased PT 2.1°±2.6° at heal strike during walking (p= 0.04). The greatest increase of 10.6°±5.4° (p\u3c 0.001) occurred at flexion during forward bend. Ball pick up also saw a similar increase at flexion and knee bend. PT at standing increased 4.4°±2.8° (p=0.001) and 2.0°±2.1° (p=0.05) during forward bend and standing respectively. While increased PT tended to correspond to increased LL, the increased LL was only statistically significant while standing during the forward bend activity (7.0°±7.2°). Hamstring stretching was effective for increasing anterior pelvic tilt during gait, forward bending tasks, and standing. The effect that increased PT has on LL is still a topic for further investigation. Future studies should include increased sample size and improvement of the LL correction method
REGULATION OF CANCER METASTASIS BY PROTEIN KINASE D1: A GLOBAL REGULATORY CASCADE
Get PDFProtein Kinase D1 (PKD1) is a serine threonine kinase which is downregulated in Prostate, Breast and Colon Cancer. It functions as a tumor suppressor in different cancer cells. Downregulation of PKD1 is known to be associated with aggressiveness of the cancer. PKD1 is known to regulate many key oncogenic signaling pathways such as E-cadherin, β-catenin and Androgen Receptor signaling pathways. Aberrant expression of these oncogenic pathways leads to transformation of cells from normal to malignant phenotype, thereby leading to increased proliferation, growth and metastasis to distant organs of these cancer cells. Literature evidence also points to the fact that E-cadherin β-catenin and PKD1 play a role in regulation of epithelial mesenchymal transition (EMT). To fully understand how PKD1 regulates β-catenin signaling, we investigated the effect of PKD1 overexpression on β-catenin signaling in colon cancer cells. We observed that PKD1 overexpression is responsible for inhibition of cell proliferation and colony formation ability of different colon cancer cell lines. Moreover, nuclear PKD1 overexpression leads to inhibition of β-catenin transcription activity in colon cancer cells. Further evaluation in in vivo mouse model showed that PKD1 is responsible for inhibition of colon cancer tumor growth in xenograft mouse model. This paved way for us to look for the effect of PKD1 on other downstream targets of β-catenin pathway which regulate EMT process in cancer cells such as Metastasis associated Protein 1. Metastasis associated Protein 1 (MTA1) is a nucleosome remodeling and histone deacetylase protein (NuRD) which is overexpressed in all the cancers. MTA1 is an initiator of epithelial and mesenchymal transition and is responsible for cancer cells metastasizing to different organs of the body. Expression of MTA1 directly correlates with the aggressiveness of the cancer. MTA1 is known to regulate β-catenin and Androgen Receptor signaling pathways leading to cancer cells acquiring metastatic capabilities. Therefore, in our study we evaluated the inverse correlation between MTA1 and PKD1 in different cancer cells. To investigate the cellular effect of PKD1 in prostate and colon cancer, stable PKD1 overexpressing prostate (C4-2) and colon cancer cells (SW480) were utilized. PKD1 overexpression inhibited MTA1 expression in prostate and colon cancer cells. PKD1 interacts, phosphorylate, translocate and degrades MTA1. Kinase domain and N terminal domain of PKD1 play a significant role in MTA1 interaction and phosphorylation. Phosphorylation of MTA1 leads to nuclear export via golgi and trans-golgi network to lysosome. Bryostatin-1 is a macrocyclic lactone which modulates PKD1 activity. Bryostatin-1 was used to activate PKD1 expression in C4-2 cells and MTA1 translocation was then tracked. This translocation of MTA1 to lysosome is a ubiquitin dependent phenomenon leading protein degradation. PKD1 overexpression leads to inhibition of tumor growth and bone metastasis leading to inhibition of osteoblast to osteoclast formation as determined by RANK expression. PTEN Knockout and TRAMP mouse model also show inverse correlation between PKD1 and MTA1 expression in prostate tissues at different weeks. Human tissue microarray of prostate, colon and breast cancer (MTA1 is overexpressed and PKD1 is downregulated in breast cancer, therefore, we tested our hypothesis in breast cancer as well) showed inverse correlation between PKD1 and MTA1 in different grade tumor tissue signifying clinical relevance of this correlation. For proof of concept of our hypothesis we used ormeloxifene because Bryostatin-1 has mild toxicity issue. Ormeloxifene is a novel modulator of PKD1 activity and it targets rapidly dividing cells Further, we investigated the effect of ormeloxifene on activation of PKD1 leading to inhibition of cancer metastasis. We observed specific activation of PKD1 expression of ormeloxifene which inhibited MTA1 expression leading to inhibition of tumor growth in xenograft mouse. We further evaluated the efficacy of ormeloxifene to inhibit metastatic prostate cancer cells (PC3 and DU145). Ormeloxifene showed excellent anti-cancer efficacy against prostate cancer as it inhibited cell proliferation, invasion and migration of metastatic prostate cancer cells. Moreoever, ormeloxifene induced cell cycle arrest at G0/G1 phase by regulating key cell cycle regulatory proteins. It also inhibited metastasis of prostate cancer leading to inhibition of key metastatic markers involved to epithelial mesenchymal transition. Ormeloxifene also showed excellent in vivo efficacy against metastatic prostate cancer cells. Therefore, ormeloxifene could be a potential therapeutic modality for metastatic cancers as it targets EMT signaling. To conclude, we for the very first time have elucidated a novel regulatory mechanism of PKD1 mediated regulation of MTA1 that plays an important role in cancer progression and metastasis. For cancer cells to metastasize PKD1 expression is suppressed with subsequent increased expression of MTA1. We elucidated that repression of MTA1 with subsequent activation of MTA1 leads to attenuation of cancer metastasis. Moreover, therapeutic modality that targets this novel regulatory pathway leading to activation of PKD1 and inhibition of MTA1 is an ideal candidate for treatment of advanced stage metastatic cancers
ICD-10 Implementation: What Impact did it have on Medical Facilities Across the Country?
Get PDFThe Department of Health and Human Services mandated that all Health InsurancePortability and Accountability Act (HIPAA) covered entities implement The International Classification of Diseases tenth edition (ICD-10) on October 1, 2015. The United States was the last industrialized country to move to the new coding system. A survey of HIM professionals was conducted across the United States to determine what efforts they experienced during the implementation of ICD-10; outline a timeline of implementation efforts for the transition of ICD-9 to ICD-10; uncover the major expenses organizations incurred through the implantation process; define training initiatives; and disclose the financial impact the transition caused. The response rate for this survey was low; however, the data collected yielded evidence that many organizations experienced similar implementation efforts regardless of the size or type of facility