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740 result(s) for "Martin, Michelle D."
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The other side of MMPs: Protective roles in tumor progression
The matrix metalloproteinase (MMP) family of extracellular proteinases have long been associated with cancer invasion and metastasis by virtue of their ability to collectively degrade all components of the extracellular matrix (ECM). The general belief that overexpression of a specific MMP, either by tumor cells or the surrounding stroma, is pro-tumorigenic led to the development of synthetic MMP inhibitors for the treatment of cancer. However, there is an increasing amount of literature demonstrating that the expression of certain MMPs, either at the primary or the metastatic site, provides a beneficial and protective effect in multiple stages of cancer progression. Here, we review the evidence for protective effects of MMPs and contrast this with pro-tumorigenic effects of either the same enzyme, or a different MMP of the same family. These studies highlight the importance of targeting specific MMPs for cancer treatment, and point to a potential reason why clinical trials of pharmaceutical inhibitors for MMPs were disappointing. In order to effectively target MMPs in cancer progression, a better understanding of both their pro- and anti-tumorigenic effects is required.
Improving Recruitment Through Social Media and Web-Based Advertising to Evaluate the Genetic Risk and Long-Term Complications in Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: Community-Based Survey
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are genetically mediated, life-threatening reactions usually caused by a medication in adults. These genetic associations promise an opportunity for pre-prescription screening, prevention, and understanding influences at a population level. Importantly, older adults disproportionally face more severe SJS/TEN reactions and higher mortality rates. However, the study of genetic risk and long-term sequelae of SJS/TEN across racially diverse populations and age groups is hampered by many factors, including rarity, social disparities, and trust in health care and providers, impacting access to hospital- and clinic-based research studies. This paper aims to explore the utility of multiple social media and web-based search tools to increase study enrollment numbers, diversity, and inclusivity of all populations and ages in the SJS Survivor Study. The community-based SJS/TEN Survivor Study remotely recruited drug-induced SJS/TEN survivors in the United States. The aims were to help determine genetic risk and long-term outcomes of SJS/TEN. Baseline recruitment included advertisements through the SJS Foundation website and American Burn Association newsletter. Two years into the study, in hopes of improving accessibility and enrollment diversity, social media ads were introduced on the Vanderbilt University Medical Center (VUMC) Facebook and Instagram accounts. Posts were created using flyers and 60-second SJS/TEN survivor video vignettes. Finally, we launched a nationwide Google Ad campaign. To understand the impact of the additional online advertising, we measured the change in registration in both the study interest and the effectiveness of implementation of specific social media and web-based search tools before and after implementation. With the introduction of social media and Google Ads, we report a 48.6% increase in enrollment overall and a 289.5% increase in participation interest. We noticed the ads were accessible to all age groups and notably reported a more even age distribution of enrolled participants from 18 through 74 years, with an average of 15% enrolled in each age category. The largest increase in any age category was seen in the 65- to 74-year-old patients (n=19), with 16.5% of the age distribution. The most significant increase in enrollment and diversity of responses came from Google Ads, with a total of 201 expressions of interest, from 56 enrolled participants, 33% of which self-identified as non-White. VUMC Facebook ads had an enrollment rate of 15.3%, and VUMC Instagram ads saw an enrollment rate of 14.3%. Social media and web-based search tools differ in their enrollment effectiveness. Google Ads were found to be the most effective advertisement for recruitment in this community-based study. Each of the social media and web-based strategies used increased enrollment numbers, accessibility to more age ranges, and diversity of enrollment. They show promise as tools to improve inclusion and enrollment in rare disease research such as SJS/TEN.
The application of a murine bone bioreactor as a model of tumor: bone interaction
A limited number of in vivo models that rapidly assess bone development or allow for the study of tumor progression in a closed in vivo environment exist. To address this, we have used bone tissue engineering techniques to generate a murine in vivo bone bioreactor. The bioreactor was created by implanting an osteoconductive hydroxyapatite scaffold pre-loaded with saline as a control or with bone morphogenetic protein-2 (BMP-2) to the murine femoral artery. Control and BMP-2 bioreactors were harvested and histologically assessed for vascularization and bone formation at 6 and 12 weeks post implantation. BMP-2 significantly enhanced the formation of osteoid within the bioreactor in comparison to the controls. To test the in vivo bone bioreactor as a model of tumor: bone interaction, FVB mice were implanted with control or BMP-2 treated bioreactors. After 6 weeks, an osteolytic inducing mammary tumor cell line tagged with luciferase (PyMT-Luc) derived from the polyoma virus middle T (PyMT) model of mammary tumorigenesis was delivered to the bioreactor via the femoral artery. Analysis of luciferase expression over time demonstrated that the presence of osteoid in the BMP-2 treated bioreactors significantly enhanced the growth rate of the PyMT-Luc cells in comparison to the control group. These data present a unique in vivo model of ectopic bone formation that can be manipulated to address molecular questions that pertain to bone development and tumor progression in a bone environment.
Mammalian Srb/Mediator complex is targeted by adenovirus E1A protein
Adenovirus E1A proteins prepare the host cell for viral replication, stimulating cell cycling and viral transcription through interactions with critical cellular regulatory proteins such as RB 1 , 2 and CBP 3 . Here we show that the E1A zinc-finger domain that is required to activate transcription of viral early genes binds to a host-cell multiprotein complex containing homologues of yeast Srb/Mediator proteins 4 , 5 . This occurs through a stable interaction with the human homologue of Caenorhabditis elegans SUR-2, a protein required for many developmental processes in the nematode 6 . This human Srb/Mediator complex stimulates transcription in vitro in response to both the E1A zinc-finger and the herpes simplex virus VP16 activation domains. Interaction with human Sur-2 is also required for transcription to be activated by the activation domain of a transcription factor of the ETS-family in response to activated mitogen-activated protein (MAP) kinase.
Breast tumors that overexpress nuclear metastasis-associated 1 (MTA1) protein have high recurrence risks but enhanced responses to systemic therapies
Nuclear metastasis-associated 1(MTA1) protein is an estrogen receptor co-repressor that regulates transcription via chromatin remodeling, and MTA1 messenger ribonucleic acid (mRNA) levels are elevated in several kinds of locally advanced and metastatic tumors relative to non-metastatic tumors. Previous studies in our laboratory mapped MTA1 into a region showing significantly lower LOH (loss of heterozygosity) in primary breast cancers with metastases compared to node-negative tumors, suggesting that epigenetic alterations of MTA1 affect metastatic potential. The present study examined immunohistochemical expression of the MTA1 protein in treated and untreated primary human breast cancers to study the relationship between MTA1 expression and clinical outcome. Node-negative tumors that overexpress MTA1 protein had recurrence risks similar to node-positive tumors. In multivariate analysis of untreated node-negative tumors, highest expression of MTA1 was associated with increased relapse risk (hazard ratio (HR)=2.72, p=0.0003 for multivariate analysis). Tamoxifen and/or anthracylcene-based chemotherapies eliminated all MTA1 associations with clinical outcome, suggesting MTA1 overexpression predicts early disease relapse, but sensitizes breast tumors to systemic therapies.
Establishment and quantitative imaging of a 3D lung organotypic model of mammary tumor outgrowth
The lung is the second most common site of metastatic spread in breast cancer and experimental evidence has been provided in many systems for the importance of an organ-specific microenvironment in the development of metastasis. To better understand the interaction between tumor and host cells in this important secondary site, we have developed a 3D in vitro organotypic model of breast tumor metastatic growth in the lung. In our model, cells isolated from mouse lungs are placed in a collagen sponge to serve as a scaffold and co-cultured with a green fluorescent protein-labeled polyoma virus middle T antigen (PyVT) mammary tumor cell line. Analysis of the co-culture system was performed using flow cytometry to determine the relative constitution of the co-cultures over time. This analysis determined that the cultures consisted of viable lung and breast cancer cells over a 5-day period. Confocal microscopy was then used to perform live cell imaging of the co-cultures over time. Our studies determined that host lung cells influence the ability of tumor cells to grow, as the presence of lung parenchyma positively affected the proliferation of the mammary tumor cells in culture. In summary, we have developed a novel in vitro model of breast tumor cells in a common metastatic site that can be used to study tumor/host interactions in an important microenvironment.
Current state of Alzheimer’s fluid biomarkers
Alzheimer’s disease (AD) is a progressive neurodegenerative disease with a complex and heterogeneous pathophysiology. The number of people living with AD is predicted to increase; however, there are no disease-modifying therapies currently available and none have been successful in late-stage clinical trials. Fluid biomarkers measured in cerebrospinal fluid (CSF) or blood hold promise for enabling more effective drug development and establishing a more personalized medicine approach for AD diagnosis and treatment. Biomarkers used in drug development programmes should be qualified for a specific context of use (COU). These COUs include, but are not limited to, subject/patient selection, assessment of disease state and/or prognosis, assessment of mechanism of action, dose optimization, drug response monitoring, efficacy maximization, and toxicity/adverse reactions identification and minimization. The core AD CSF biomarkers Aβ42, t-tau, and p-tau are recognized by research guidelines for their diagnostic utility and are being considered for qualification for subject selection in clinical trials. However, there is a need to better understand their potential for other COUs, as well as identify additional fluid biomarkers reflecting other aspects of AD pathophysiology. Several novel fluid biomarkers have been proposed, but their role in AD pathology and their use as AD biomarkers have yet to be validated. In this review, we summarize some of the pathological mechanisms implicated in the sporadic AD and highlight the data for several established and novel fluid biomarkers (including BACE1, TREM2, YKL-40, IP-10, neurogranin, SNAP-25, synaptotagmin, α-synuclein, TDP-43, ferritin, VILIP-1, and NF-L) associated with each mechanism. We discuss the potential COUs for each biomarker.
Histotype-tailored neoadjuvant chemotherapy versus standard chemotherapy in patients with high-risk soft-tissue sarcomas (ISG-STS 1001): an international, open-label, randomised, controlled, phase 3, multicentre trial
Previous trials from our group suggested an overall survival benefit with five cycles of adjuvant full-dose epirubicin plus ifosfamide in localised high-risk soft-tissue sarcoma of the extremities or trunk wall, and no difference in overall survival benefit between three cycles versus five cycles of the same neoadjuvant regimen. We aimed to show the superiority of the neoadjuvant administration of histotype-tailored regimen to standard chemotherapy. For this international, open-label, randomised, controlled, phase 3, multicentre trial, patients were enrolled from 32 hospitals in Italy, Spain, France, and Poland. Eligible patients were aged 18 years or older with localised, high-risk (high malignancy grade, 5 cm or longer in diameter, and deeply located according to the investing fascia), soft-tissue sarcoma of the extremities or trunk wall and belonging to one of five histological subtypes: high-grade myxoid liposarcoma, leiomyosarcoma, synovial sarcoma, malignant peripheral nerve sheath tumour, and undifferentiated pleomorphic sarcoma. Patients were randomly assigned (1:1) to receive three cycles of full-dose standard chemotherapy (epirubicin 60 mg/m2 per day [short infusion, days 1 and 2] plus ifosfamide 3 g/m2 per day [days 1, 2, and 3], repeated every 21 days) or histotype-tailored chemotherapy: for high-grade myxoid liposarcoma, trabectedin 1·3 mg/m2 via 24-h continuous infusion, repeated every 21 days; for leiomyosarcoma, gemcitabine 1800 mg/m2 on day 1 intravenously over 180 min plus dacarbazine 500 mg/m2 on day 1 intravenously over 20 min, repeated every 14 days; for synovial sarcoma, high-dose ifosfamide 14 g/m2, given over 14 days via an external infusion pump, every 28 days; for malignant peripheral nerve sheath tumour, intravenous etoposide 150 mg/m2 per day (days 1, 2, and 3) plus intravenous ifosfamide 3 g/m2 per day (days 1, 2, and 3), repeated every 21 days; and for undifferentiated pleomorphic sarcoma, gemcitabine 900 mg/m2 on days 1 and 8 intravenously over 90 min plus docetaxel 75 mg/m2 on day 8 intravenously over 1 h, repeated every 21 days. Randomisation was stratified by administration of preoperative radiotherapy and by country of enrolment. Computer-generated random lists were prepared by use of permuted balanced blocks of size 4 and 6 in random sequence. An internet-based randomisation system ensured concealment of the treatment assignment until the patient had been registered into the system. No masking of treatment assignments was done. The primary endpoint was disease-free survival. The primary and safety analyses were planned in the intention-to-treat population. We did yearly futility analyses on an intention-to-treat basis. The study was registered with ClinicalTrials.gov, number NCT01710176, and with the European Union Drug Regulating Authorities Clinical Trials, number EUDRACT 2010–023484–17, and is closed to patient entry. Between May 19, 2011, and May 13, 2016, 287 patients were randomly assigned to a group (145 to standard chemotherapy and 142 to histotype-tailored chemotherapy), all of whom, except one patient assigned to standard chemotherapy, were included in the efficacy analysis (97 [34%] with undifferentiated pleomorphic sarcoma; 64 [22%] with high-grade myxoid liposarcoma; 70 [24%] with synovial sarcoma; 27 [9%] with malignant peripheral nerve sheath tumour; and 28 [10%] with leiomyosarcoma). At the third futility analysis, with a median follow-up of 12·3 months (IQR 2·75–28·20), the projected disease-free survival at 46 months was 62% (95% CI 48–77) in the standard chemotherapy group and 38% (22–55) in the histotype-tailored chemotherapy group (stratified log-rank p=0·004; hazard ratio 2·00, 95% CI 1·22–3·26; p=0·006). The most common grade 3 or higher adverse events in the standard chemotherapy group (n=125) were neutropenia (107 [86%]), anaemia (24 [19%]), and thrombocytopenia (21 [17%]); the most common grade 3 or higher adverse event in the histotype-tailored chemotherapy group (n=114) was neutropenia (30 [26%]). No treatment-related deaths were reported in both groups. In agreement with the Independent Data Monitoring Committee, the study was closed to patient entry after the third futility analysis. In a population of patients with high-risk soft-tissue sarcoma, we did not show any benefit of a neoadjuvant histotype-tailored chemotherapy regimen over the standard chemotherapy regimen. The benefit seen with the standard chemotherapy regimen suggests that this benefit might be the added value of neoadjuvant chemotherapy itself in patients with high-risk soft-tissue sarcoma. European Union grant (Eurosarc FP7 278472).
Fate mapping of human glioblastoma reveals an invariant stem cell hierarchy
Human glioblastomas harbour a subpopulation of glioblastoma stem cells that drive tumorigenesis. However, the origin of intratumoural functional heterogeneity between glioblastoma cells remains poorly understood. Here we study the clonal evolution of barcoded glioblastoma cells in an unbiased way following serial xenotransplantation to define their individual fate behaviours. Independent of an evolving mutational signature, we show that the growth of glioblastoma clones in vivo is consistent with a remarkably neutral process involving a conserved proliferative hierarchy rooted in glioblastoma stem cells. In this model, slow-cycling stem-like cells give rise to a more rapidly cycling progenitor population with extensive self-maintenance capacity, which in turn generates non-proliferative cells. We also identify rare ‘outlier’ clones that deviate from these dynamics, and further show that chemotherapy facilitates the expansion of pre-existing drug-resistant glioblastoma stem cells. Finally, we show that functionally distinct glioblastoma stem cells can be separately targeted using epigenetic compounds, suggesting new avenues for glioblastoma-targeted therapy. Using unique barcodes for tumour cells, the authors explore the dynamics of human glioblastoma subpopulations, and suggest that clonal heterogeneity emerges through stochastic fate decisions of a neutral proliferative hierarchy. Brain tumour cell hierarchy Cancers are heterogeneous between patients and between tumour cells. It is still difficult to identify the subpopulations of cells that most contribute to tumour growth and those that are targeted by therapy. Xiaoyang Lan et al . now explore the dynamics of human glioblastoma (GBM) subpopulations using barcodes for tumour cells. They suggest that a proliferative hierarchy emerges through stochastic cell fate decision. In this model, slow-cycling stem cells give rise to rapidly proliferative progenitors that fuel tumour growth and which in turn generate cells that are short-lived and do not proliferate. This is in contrast to a clonal evolution model based on the different fitness of cells that are selected for. The authors also identify a rare subpopulation of GBM cells that is resistant to TMZ treatment (the common treatment for GBM) but can be targeted by drug combinations.