Challenges and opportunities faced by nurse scientists in integrating data and technology in research to promote health equity.

Advances in technologies including omics, apps, imaging, sensors, and big data are increasingly being integrated into research by nurse scientists, but the impact on improving health equity is still unclear. In this article, nursing research faculty from one institution discuss challenges and opportunities experienced when integrating various technologies into their research aimed at promoting health equity. Using exemplars from faculty experiences, a three-pronged approach to keeping patients and communities and the goal of health equity central in research while incorporating advancing technologies is described. This approach includes establishing long-term engagement with populations underrepresented in research, adopting strategies to increase diversity in study participant recruitment, and training and collaboration among a diverse workforce of educators, clinicians, and researchers. Training nurse scientists in integrating data and technology for advancing the science on health equity will shift the culture of how we understand, collaborate, and grow with the communities in which we train and practice as nurse scientists.

Impact of the COVID-19 pandemic on cancer patients and psycho-oncology providers: Perspectives, observations, and experiences of the American Psychosocial Oncology Society membership.

OBJECTIVE: To understand: (1) psycho-oncology providers' perspectives on and observations of the psychological responses of their cancer patients during the pandemic, and (2) psycho-oncology providers' own experiences delivering care. METHODS: In this concurrent mixed methods study, a survey was distributed to psychosocial providers who were members of the American Psychosocial Oncology Society (APOS). Survey respondents were invited to participate in a one-on-one audio-recorded interview via phone or secure Zoom®. RESULTS: seventy-six self-identified psycho-oncology providers responded to the survey and 11 participated in a one-on-one interview. Approximately half reported that patients responded in unique ways to COVID-19 stress relative to other populations. Three themes emerged from qualitative analyses: (1) unique burden on patients, (2) cancer patients' pandemic response and its relationship to their cancer experience, and (3) unexpected positive changes. Providers emphasized that the cancer experience may have prepared patients for the existential distress of the pandemic and described patients' resiliency. Two themes emerged regarding delivery of care: (1) new professional and personal challenges and (2) provider resiliency. CONCLUSIONS: Although providers observed that the pandemic placed new burdens on patients, they emphasized that the cancer experience may have prepared patients for the existential distress of the pandemic and described patients' resiliency. To overcome challenges, psycho-oncology providers used innovative strategies to support patients and foster their own mental health.

An integrative review of factors associated with telomere length and implications for biobehavioral research.

BACKGROUND: Although telomere shortening occurs as a natural part of aging, there is now a robust body of research that suggests that there is a relationship between psychosocial, environmental, and behavioral factors and changes in telomere length. These factors need to be considered when integrating telomere measurement in biobehavioral research studies. OBJECTIVES: This article provides a brief summary of the known facts about telomere biology and an integrative review of current human research studies that assessed relationships between psychosocial, environmental, or behavioral factors and telomere length. METHODS: An integrative review was conducted to examine human research studies that focused on psychosocial, environmental, and behavioral factors affecting telomere length and telomerase activity using the electronic databases PubMed/Medline and CINAHL from 2003 to the present. In addition to the known individual factors that are associated with telomere length, the results of the integrative review suggest that perceived stress, childhood adversities, major depressive disorder, educational attainment, physical activity, and sleep duration should also be measured. DISCUSSION: Multiple factors have been shown to affect telomere length. To advance understanding of the role of telomere length in health and disease risk, it will be important to further elucidate the mechanisms that contribute to telomere shortening.

Telomere length: a review of methods for measurement.

BACKGROUND: The exciting discovery that telomere shortening is associated with many health conditions and that telomere lengths can be altered in response to social and environmental exposures has underscored the need for methods to accurately and consistently quantify telomere length. OBJECTIVES: The purpose of this article is to provide a comprehensive summary that compares and contrasts the current technologies used to assess telomere length. DISCUSSION: Multiple methods have been developed for the study of telomeres. These techniques include quantification of telomere length by terminal restriction fragmentation-which was one of the earliest tools used for length assessment-making it the gold standard in telomere biology. Quantitative polymerase chain reaction provides the advantage of being able to use smaller amounts of DNA, thereby making it amenable to epidemiology studies involving large numbers of people. An alternative method uses fluorescent probes to quantify not only mean telomere lengths but also chromosome-specific telomere lengths; however, the downside of this approach is that it can only be used on mitotically active cells. Additional methods that permit assessment of the length of a subset of chromosome-specific telomeres or the subset of telomeres that demonstrate shortening are also reviewed. CONCLUSION: Given the increased utility for telomere assessments as a biomarker in physiological, psychological, and biobehavioral research, it is important that investigators become familiar with the methodological nuances of the various procedures used for measuring telomere length. This will ensure that they are empowered to select an optimal assessment approach to meet the needs of their study designs. Gaining a better understanding of the benefits and drawbacks of various measurement techniques is important not only in individual studies, but also to further establish the science of telomere associations with biobehavioral phenomena.

MicroRNA Profiles in Hematopoietic Stem Cell Transplant Recipients.

Background: Hematopoietic Stem Cell Transplant (HCT) is a potentially curative treatment for hematologic malignancies, including multiple myeloma. Biomarker investigation can guide identification of HCT recipients at-risk for poor outcomes. MicroRNAs (miRNAs) are a class of non-coding RNAs involved in the modulation and regulation of pathological processes and are emerging as prognostic and predictive biomarkers for multiple health conditions. This pilot study aimed to examine miRNA profiles associated with HCT-related risk factors and outcomes in patients undergoing autologous HCT. Methods: Patients eligible for autologous HCT were recruited and blood samples and HCT-related variables were collected. Differential expression analysis of miRNA was conducted on 24 patient samples to compare changes in miRNA profile in HCT eligible patients before and after transplant. Results: Unsupervised clustering of differentially expressed (p < .05) miRNAs pre- and post- HCT identified clusters of up- and down-regulated miRNAs. Four miRNAs (miR-125a-5p, miR-99b-5p, miR-382-5p, miR-145-5p) involved in hematopoiesis (differentiation of progenitor cells, granulocyte function, thrombopoiesis, and tumor suppression) were significantly downregulated post-HCT. Correlation analyses identified select miRNAs associated with risk factors (such as frailty, fatigue, cognitive decline) and quality of life pre- and post-HCT. Select miRNAs were correlated with platelet engraftment. Conclusion: Future studies should examine miRNA signatures in larger cohorts in association with HCT outcomes; and expand investigations in patients receiving allogeneic transplants. This will lead to identification of biomarkers for risk stratification of HCT recipients.

Long COVID incidence in adults and children between 2020 and 2023: a real-world data study from the RECOVER Initiative.

Estimates of post-acute sequelae of SARS-CoV-2 infection (PASC) incidence, also known as Long COVID, have varied across studies and changed over time. We estimated PASC incidence among adult and pediatric populations in three nationwide research networks of electronic health records (EHR) participating in the RECOVER Initiative using different classification algorithms (computable phenotypes). Overall, 7% of children and 8.5%-26.4% of adults developed PASC, depending on computable phenotype used. Excess incidence among SARS-CoV-2 patients was 4% in children and ranged from 4-7% among adults, representing a lower-bound incidence estimation based on two control groups - contemporary COVID-19 negative and historical patients (2019). Temporal patterns were consistent across networks, with peaks associated with introduction of new viral variants. Our findings indicate that preventing and mitigating Long COVID remains a public health priority. Examining temporal patterns and risk factors of PASC incidence informs our understanding of etiology and can improve prevention and management.

DNA Methylation Research in Autologous Hematopoietic Stem Cell Transplant Population.

Despite increased sophistication in DNA methylation (DNAm) measurement and methods, conducting studies in specific populations such as the hematopoietic stem cell transplant (HCT) population, presents unique challenges and study design considerations. In this article, we explain the motivation for investigating DNAm in the HCT population, highlighting important study design features and key findings in a longitudinal prospective pilot study of DNAm in 32 patients undergoing autologous HCT in Central Virginia, USA. We also discuss limitations and challenges to generating robust results. We observed that HCT does not prevent high-quality DNA from being extracted from whole blood for DNAm research and that longitudinal prospective studies that span pre- and 2-months post-HCT are feasible. Critically, we did not observe significant impacts of cancer diagnosis, time since transplant, age, or chromosomal sex on overall DNAm data dimensionality. These observations demonstrate that while extreme care is required to ensure generalizable, accurate, and interpretable results, researchers should not avoid HCT-DNAm research simply for fear that the transplant procedure or presence of a cancer diagnosis will prevent meaningful conclusions from being drawn. DNAm is an attractive biomarker that is understudied in patients undergoing HCT and needs to expand to improve precise prediction of HCT outcomes.

DNA Methylation Changes in Autologous Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: Blood cancers may be potentially cured with hematopoietic stem cell transplantation (HCT); however, standard pre-assessments for transplant eligibility do not capture all contributing factors for transplant outcomes. Epigenetic biomarkers predict outcomes in various diseases. This pilot study aims to explore epigenetic changes (epigenetic age and differentially methylated genes) in patients before and after autologous HCT, that can serve as potential biomarkers to better predict HCT outcomes. METHODS: This study used a prospective longitudinal study design to compare genome wide DNA methylation changes in 36 autologous HCT eligible patients recruited from the Cellular Immunotherapies and Transplant clinic at a designated National Cancer Center. RESULTS: Genome-wide DNA methylation, measured by the Illumina Infinium Human Methylation 850K BeadChip, showed a significant difference in DNA methylation patterns post-HCT compared to pre-HCT. Compared to baseline levels of DNA methylation pre-HCT, 3358 CpG sites were hypo-methylated and 3687 were hyper-methylated. Identified differentially methylated positions overlapped with genes involved in hematopoiesis, blood cancers, inflammation and immune responses. Enrichment analyses showed significant alterations in biological processes such as immune response and cell structure organization, however no significant pathways were noted. Though participants had an advanced epigenetic age compared to chronologic age before and after HCT, both epigenetic age and accelerated age decreased post-HCT. CONCLUSION: Epigenetic changes, both in epigenetic age and differentially methylated genes were observed in autologous HCT recipients, and should be explored as biomarkers to predict transplant outcomes after autologous HCT in larger, longitudinal studies.

Hematopoietic Stem Cell Transplantation Patients Are Skilled at Adapting to "Out of the Ordinary" Situations: A Qualitative Study.

OBJECTIVE: Blood cancers can potentially be cured by hematopoietic stem cell transplantation (HCT), but HCT recipients can remain immunocompromised for extended periods of time and require caregiver support. Though the COVID-19 pandemic has globally affected the livelihood and well-being of all individuals, it has affected certain populations in unique ways, HCT recipients being one of them. This study intends to understand the lived experience of HCT recipients and HCT-eligible patients during the COVID-19 pandemic. DATA SOURCES: This qualitative study enrolled participants (N=25) from a parent study that recruited transplant patients (HCT eligible or HCT recipients) between May and October 2020. Participants were invited to participate on a one-on-one interview via an electronic platform. A phenomenologic qualitative approach was used to identify emerging themes and subthemes. CONCLUSION: Three themes were developed: a) the pandemic experience was influenced by the transplant journey; b) participants found ways to thrive despite the odds and access support in unique ways; and c) participants described challenges during the pandemic regarding non-transplant care, vaccine considerations, and distrust in media. IMPLICATIONS FOR NURSING PRACTICE: Results from this study highlighted that HCT recipients were uniquely prepared for "out of the ordinary" situations during the pandemic and underscored challenges faced by them during this time, identifying areas for improvement in the health care system. Nurses in their unique role can initiate and lead process changes to address barriers such as lack of access to reliable information, poor communication, and inadequate resources for accessing non-transplant care especially during uncertain times.

Perceptions and Experiences of Hematopoietic Cell Transplantation Patients During the COVID-19 Pandemic.

OBJECTIVES: Since March 2020, the severe acute respiratory syndrome coronavirus-2 pandemic has affected the global community, but poses unique challenges for individuals with cancer. Patients diagnosed with hematologic malignancies undergo aggressive therapies followed by hematopoietic cell transplantation (HCT) as a potential curative treatment. HCT recipients can be immunocompromised for extended periods of time, and even pre-pandemic, transplant patients reported depression and anxiety due to restrictions and infection prevention measures they had to adhere to as part of transplant precautions. This study aimed to understand psychological distress and capture perspectives on coping strategies and access to healthcare in the HCT population during the COVID-19 pandemic. DATA SOURCES: Adult patients who received a transplant or were awaiting transplant and had a scheduled appointment at the transplant clinic were eligible to participate in this cross-sectional study. Participants completed an online survey that included questionnaires, clinical data and demographic information. CONCLUSION: Fifty-four participants completed the survey. HCT participants reported relatively high psychological distress during the initial phase of the COVID-19 pandemic, but indicated use of healthy coping mechanisms to deal with stress. IMPLICATION FOR NURSING PRACTICE: Study data informs healthcare providers that psychological distress and mental health warrants increased attention during periods of heightened stress. Education and resources on healthy, beneficial coping strategies should be provided to support HCT patients. Nurses and advanced nurse practitioners are well poised to interact with HCT patients and provide necessary support or appropriate referral during routine clinical interactions, preparing patients for prolonged effects of the pandemic and similar future events.

Factors Affecting Quality of Life in Patients Receiving Autologous Hematopoietic Stem Cell Transplantation.

BACKGROUND: Hematopoietic stem cell transplant (HSCT) is a potentially curative treatment for hematologic malignancies, with 22 000 HSCTs performed annually in the United States. However, decreased quality of life (QoL) is a frequent and concerning state reported by HSCT recipients. OBJECTIVES: We sought to determine if measurements of frailty and cognitive impairment were associated with fatigue and QoL in adult HSCT recipients after autologous HSCT. METHODS: Using a longitudinal study design, 32 participants 18 years or older receiving autologous HSCT were recruited from a bone marrow transplant clinic. Each participant completed 2 visits: pre-HSCT and post-HSCT. At each visit, participants completed assessment tools to measure frailty, cognitive impairment, fatigue, and QoL (assesses physical, social/family, emotional, functional, and transplant-related well-being). RESULTS: Participants with increased fatigue scores reported decreased QoL pre- and post-HSCT. Participants with increased frailty showed decreased functional well-being before HSCT and showed correlations with decreased physical, social, and transplant-related well-being post-HSCT. As expected, fatigued participants also showed increased frailty post-HSCT. Participants showed significant changes in physical well-being and fatigue between pre-HSCT and post-HSCT visits. CONCLUSION: Data analyses from this pilot study show significant correlations between subsets of QoL with fatigue and frailty in autologous HSCT participants pre- and post-HSCT. IMPLICATIONS FOR PRACTICE: Understanding the impact of frailty on fatigue and QoL in HSCT recipients is critical to assist nurses in initiating educational and behavioral interventions to help mitigate the effects of HSCT.

Biobehavioral Implications of Covid-19 for Transplantation and Cellular Therapy Recipients.

A growing body of literature has emphasized the importance of biobehavioral processes - defined as the interaction of behavior, psychology, socioenvironmental factors, and biological processes - for clinical outcomes among transplantation and cellular therapy (TCT) patients. TCT recipients are especially vulnerable to distress associated with pandemic conditions and represent a notably immunocompromised group at greater risk for SARS-CoV-2 infection with substantially worse outcomes. The summation of both the immunologic and psychologic vulnerability of TCT patients renders them particularly susceptible to adverse biobehavioral sequelae associated with the Covid-19 pandemic. Stress and adverse psychosocial factors alter neural and endocrine pathways through sympathetic nervous system and hypothalamic-pituitary-adrenal axis signaling that ultimately affect gene regulation in immune cells. Reciprocally, global inflammation and immune dysregulation related to TCT contribute to dysregulation of neuroendocrine and central nervous system function, resulting in the symptom profile of depression, fatigue, sleep disturbance, and cognitive dysfunction. In this article, we draw upon literature on immunology, psychology, neuroscience, hematology and oncology, Covid-19 pathophysiology, and TCT processes to discuss how they may intersect to influence TCT outcomes, with the goal of providing an overview of the significance of biobehavioral factors in understanding the relationship between Covid-19 and TCT, now and for the future. We discuss the roles of depression, anxiety, fatigue, sleep, social isolation and loneliness, and neurocognitive impairment, as well as specific implications for sub-populations of interest, including pediatrics, caregivers, and TCT donors. Finally, we address protective psychological processes that may optimize biobehavioral outcomes affected by Covid-19.

Identification of a novel cell death receptor mediating IGFBP-3-induced anti-tumor effects in breast and prostate cancer.

Insulin-like growth factor-binding protein-3 (IGFBP-3), a major regulator of endocrine actions of IGFs, is a p53-regulated potent apoptotic factor and is significantly suppressed in a variety of cancers. Recent epidemiologic studies suggest that IGFBP-3 contributes to cancer risk protection in a variety of cancers, and a polymorphic variation of IGFBP-3 influences cancer risk, although other studies vary in their conclusions. Some antiproliferative actions of IGFBP-3 have been reported to be independent of IGFs, but the precise biochemical/molecular mechanisms of IGF-independent, antiproliferative actions of IGFBP-3 are largely unknown. Here we report a new cell death receptor, IGFBP-3R, that is a single-span membrane protein and binds specifically to IGFBP-3 but not other IGFBP species. Expression analysis of IGFBP-3 and IGFBP-3R indicates that the IGFBP-3/IGFBP-3R axis is impaired in breast and prostate cancer. We also provide evidence for anti-tumor effect of IGFBP-3R in vivo using prostate and breast cancer xenografts in athymic nude mice. Further in vitro studies demonstrate that IGFBP-3R mediates IGFBP-3-induced caspase-8-dependent apoptosis in various cancer cells. Knockdown of IGFBP-3R attenuated IGFBP-3-induced caspase activities and apoptosis, whereas overexpression of IGFBP-3R enhanced IGFBP-3 biological effects. IGFBP-3R physically interacts and activates caspase-8, and knockdown of caspase-8 expression or activity inhibited IGFBP-3/IGFBP-3R-induced apoptosis. Here, we propose that IGFBP-3R represents a novel cell death receptor and is essential for the IGFBP-3-induced apoptosis and tumor suppression. Thus, the IGFBP-3/IGFBP-3R axis may provide therapeutic and prognostic value for the treatment of cancer.

Frailty in Patients With Hematologic Malignancies and Those Undergoing Transplantation: A Scoping Review.

PROBLEM IDENTIFICATION: Although frailty is an important parameter in treatment planning and in predicting prognosis and overall survival among patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation, frailty assessment tools are not standardized in clinical care settings. The purpose of this article is to provide an overview of the literature on frailty assessment tools in these patient populations. LITERATURE SEARCH: A systematic search of CINAHL®, Embase®, MEDLINE®, PubMed®, and Web of Science was performed using keywords and controlled vocabulary for the concepts "bone marrow transplants," "hematologic neoplasms," and "frailty." DATA EVALUATION: Extracted data included study type, diagnosis, transplantation status, frailty tools used, and outcome measures. SYNTHESIS: A systematic search resulted in 24 studies that met the inclusion criteria. There were significant differences in how various groups define and assess frailty. IMPLICATIONS FOR PRACTICE: Addressing the lack of standardized frailty assessments will assist healthcare providers to routinely integrate frailty measures in clinical assessments to identify those at risk for poor outcomes, improving personalized care.

Health Promoting Life-Style Behaviors and Systemic Inflamma-tion in African American and Caucasian Women Prior to Chemo-therapy for Breast Cancer.

BACKGROUND: Racial disparities in breast cancer outcomes persist, with differential adverse outcomes in African American women. Although research has ex-amined possible genetic differences, there has been little research on potentially modifiable characteristics such as health promoting behaviors. The purpose of this article is to describe the characteristics and to compare the differences by race in lifestyle factors and inflammatory biomarkers in African American and Caucasian women with breast cancer. METHODS: This is a baseline descriptive analysis from an ongoing randomized controlled trial that includes 124 women diagnosed with early stage breast cancer prior to chemotherapy. Data sources included medical records, self-re-port questionnaires and a blood sample for measures of inflammation. The sta-tistical analysis included descriptive statistics and ANOVA models to determine differences between the two groups. RESULTS: Overall, both groups had low levels of health promoting behaviors. African Americans had a significantly higher body mass index. Caucasian women consumed more alcohol. Levels of C-reactive protein and MIP-1ß were significantly higher in African Americans. CONCLUSION: Potentially modifiable factors such as nutrition, physical activity and levels of inflammation warrant further attention.

IGFBP-3 inhibits cytokine-induced insulin resistance and early manifestations of atherosclerosis.

Metabolic syndrome is associated with visceral obesity, insulin resistance and an increased risk of cardiovascular diseases. Visceral fat tissue primarily consists of adipocytes that secrete cytokines leading to a state of systemic inflammation in obese conditions. One of the IGF-independent functions of IGFBP-3 is its role as an anti-inflammatory molecule. Our study in obese adolescents show a decrease in total IGFBP-3 levels and increase in proteolyzed IGFBP-3 in circulation when compared to their normal counterparts and establishes a positive correlation between IGFBP-3 proteolysis and adiposity parameters as well as insulin resistance. In human adipocytes, we show that IGFBP-3 inhibits TNF-α-induced NF-κB activity in an IGF-independent manner, thereby restoring the deregulated insulin signaling and negating TNF-α-induced inhibition of glucose uptake. IGFBP-3 further inhibits TNF-α, CRP and high glucose-induced NF-κB activity in human aortic endothelial cells (HAECs) and subsequently suppresses monocyte adhesion to HAEC through the IGFBP-3 receptor. In conclusion, these findings suggest that reduced levels of IGFBP-3 in circulation and reduced expression of IGFBP-3 in macrophages in obesity may result in suppression of its anti-inflammatory functions and therefore IGFBP-3 may present itself as a therapeutic for obesity-induced insulin resistance and for events occurring in the early stages of atherosclerosis.

Targeting IGF-I, IGFBPs and IGF-I receptor system in cancer: the current and future in breast cancer therapy.

The IGF system plays a major role in growth, development and maintenance of homeostasis in normal cells and also contributes towards proliferation of malignant cells. Any disruption in the IGF system has its implications on growth retardation, atherosclerosis, insulin resistance and cancer. Imbalances in the IGF axis are known to contribute towards the progression of breast cancer. Due to the ubiquitous nature of the components of the IGF system, targeting specific members of the axis has gained attention over the past decades. The most elaborately investigated component as a therapeutic target in the system is the IGF-IR and studies have been pursued to inhibit IGF-IR by the administration of monoclonal antibodies and tyrosine kinase inhibitors. Very recently, a novel cell death receptor that binds specifically to IGFBP-3 was identified. It has also been shown that the IGFBP-3/IGFBP-3 receptor may be impaired in breast and prostate cancer. In this review, we present the mechanisms used to target the IGF system in various diseased states, emphasizing on breast cancer. We further discuss currently available therapeutic approaches and summarize the latest patents published in the field of IGF-I/IGF-IR and IGFBP-3/IGFBP-3R systems.

Human Oncoprotein MDM2 Up-regulates Expression of NF-κB2 Precursor p100 Conferring a Survival Advantage to Lung Cells.

The current model predicts that MDM2 is primarily overexpressed in cancers with wild-type (WT) p53 and contributes to oncogenesis by degrading p53. Following a correlated expression of MDM2 and NF-κB2 transcripts in human lung tumors, we have identified a novel transactivation function of MDM2. Here, we report that in human lung tumors, overexpression of MDM2 was found in approximately 30% of cases irrespective of their p53 status, and expression of MDM2 and NF-κB2 transcripts showed a highly significant statistical correlation in tumors with WT p53. We investigated the significance of this correlated expression in terms of mechanism and biological function. Increase in MDM2 expression from its own promoter in transgenic mice remarkably enhanced expression of NF-κB2 compared with its non-transgenic littermates. Knockdown or elimination of endogenous MDM2 expression in cultured non-transformed or lung tumor cells drastically reduced expression of NF-κB2 transcripts, suggesting a normal physiological role of MDM2 in regulating NF-κB2 transcription. MDM2 could up-regulate expression of NF-κB2 transcripts when its p53-interaction domain was blocked with Nutlin-3, indicating that the MDM2-p53 interaction is dispensable for up-regulation of NF-κB2 expression. Consistently, analysis of functional domains of MDM2 indicated that although the p53-interaction domain of MDM2 contributes to the up-regulation of the NFκB2 promoter, MDM2 does not require direct interactions with p53 for this function. Accordingly, MDM2 overexpression in non-transformed or lung cancer cells devoid of p53 also generated a significant increase in the expression of NF-κB2 transcript and its targets CXCL-1 and CXCL-10, whereas elimination of MDM2 expression had the opposite effects. MDM2-mediated increase in p100/NF-κB2 expression reduced cell death mediated by paclitaxel. Furthermore, knockdown of NF-κB2 expression retarded cell proliferation. Based on these data, we propose that MDM2-mediated NF-κB2 up-regulation is a combined effect of p53-dependent and independent mechanisms and that it confers a survival advantage to lung cancer cells.

MDM2 controls the timely expression of cyclin A to regulate the cell cycle.

Overexpression of MDM2 has been related to oncogenesis. In this communication, we present evidence to show that MDM2 controls the cell cycle-dependent expression of cyclin A by using a pathway that ensures its timely expression. MDM2 does not inhibit cyclin D or E expression. Silencing of endogenous MDM2 expression elevates cyclin A expression. The p53-binding domain of MDM2 harbors a SWIB region homologous to a conserved domain of a chromosome remodeling factor BRG1-associated protein. The SWIB domain of MDM2 inhibits cyclin A expression in a p53- and BRG1-dependent fashion, suggesting that MDM2 interferes with p53 binding of the BRG1 complex freeing it to repress cyclin A expression. Silencing of cyclin-dependent kinase (cdk) inhibitor p16 prevents MDM2-mediated inhibition of cyclin A expression, implicating its role in the process. MDM2-mediated repression of cyclin A expression induces G(1)-S arrest, which can be rescued by ectopic expression of cyclin A. Cancer cells lacking p53, p16, or BRG1 escape MDM2-mediated repression of cyclin A expression and growth arrest. Our data propose a novel mechanism by which MDM2 controls the cell cycle in normal cells and how cancer cells may escape this important safety barrier.