Personalized medicine in a community health system: the NorthShore experience.

Genomic and personalized medicine implementation efforts have largely centered on specialty care in tertiary health systems. There are few examples of fully integrated care systems that span the healthcare continuum. In 2014, NorthShore University HealthSystem launched the Center for Personalized Medicine to catalyze the delivery of personalized medicine. Successful implementation required the development of a scalable family history collection tool, the Genetic and Wellness Assessment (GWA) and Breast Health Assessment (BHA) tools; integrated pharmacogenomics programming; educational programming; electronic medical record integration; and robust clinical decision support tools. To date, more than 225,000 patients have been screened for increased hereditary conditions, such as cancer risk, through these tools in primary care. More than 35,000 patients completed clinical genetic testing following GWA or BHA completion. An innovative program trained more than 100 primary care providers in genomic medicine, activated with clinical decision support and access to patient genetic counseling services and digital healthcare tools. The development of a novel bioinformatics platform (FLYPE) enabled the incorporation of genomics data into electronic medical records. To date, over 4,000 patients have been identified to have a pathogenic or likely pathogenic variant in a gene with medical management implications. Over 33,000 patients have clinical pharmacogenomics data incorporated into the electronic health record supported by clinical decision support tools. This manuscript describes the evolution, strategy, and successful multispecialty partnerships aligned with health system leadership that enabled the implementation of a comprehensive personalized medicine program with measurable patient outcomes through a genomics-enabled learning health system model that utilizes implementation science frameworks.

Cancer-associated thrombosis by cancer sites and inherited factors in a prospective population-based cohort.

Cancer-associated thrombosis (CAT) is common and associated with mortality. We estimated CAT rate by cancer sites and inherited factors among cancer patients from the UK Biobank (N =70,406). The 12-month CAT rate after cancer diagnosis was 2.37% overall but varied considerably among cancer sites. Among the 10 cancer sites classified as 'high-risk' of CAT by the National Comprehensive Cancer Network guidelines, 6 had CAT rate <5%. In contrast, 5 cancer sites classified as 'average-risk' by the guidelines had CAT rate >5%. For inherited risk factors, both known mutation carriers in two genes (F5/F2) and polygenic score for venous thromboembolism (VTE) (PGSVTE) were independently associated with increased CAT risk. While F5/F2 identified 6% patients with high genetic-risk for CAT, adding PGSVTE identified 13 % patients at equivalent/higher genetic-risk to CAT than that of F5/F2 mutations. Findings from this large prospective study, if confirmed, provide critical data to update guidelines for CAT risk assessment.

Clinical characteristics and viral load dynamics of COVID-19 in a mildly or moderately symptomatic outpatient sample.

BACKGROUND: Studies of outpatients with mild or moderate COVID-19 are uncommon. We studied: 1) association of symptoms with reverse transcriptase polymerase chain reaction (RT-PCR) test results; and 2) association of initial RT-PCR cycle threshold (Ct) in relation to duration of RT-PCR positivity in outpatients with mild or moderate COVID-19. METHODS: This was a cohort study of outpatients with confirmed COVID-19 and at least one symptom. Participants had repeat nasopharyngeal swabs and symptom checklists every 3-5 days until two consecutive RT-PCR tests were negative. RT-PCR tests were used to assess viral load. Antibody tests for COVID-19 were performed at 2 weeks, 4 weeks, and 8 weeks after symptom onset. RESULTS: Twenty-five patients (nine females) were enrolled, ranging in age from 19-58 (median age 28 years). All patients reported at least one symptom, with a median of six symptoms per patient. Symptoms persisted for 6-67 days (median duration 18 days). In all 25 patients, blood samples collected a median of 13 days after symptom onset were positive for SARS-CoV-2 antibodies in 15 (60%). After a median of 28 days following symptom onset, 23/23 patients with available samples tested positive for antibodies. The longest duration of positive RT-PCR test was 49 days from first positive PCR test (Mean = 27.4, SD = 12.5, Median = 24). Initial Ct was significantly associated with longer duration (ß = -1.3, SE = 0.3, p<0.01 per 1 cycle higher) of RT-PCR positivity. CONCLUSIONS: In mildly or moderately ill COVID-19 outpatients, RT-PCT tests remained positive for as long as 49 days and test positivity and symptom duration correlated with initial viral load.

Outcomes after targeted treatment based on somatic tumor genetic testing for women with gynecologic cancers.

OBJECTIVE: Molecular tumor profiling and next-generation sequencing are being increasingly utilized, but there are limited data on the therapeutic implications and potential benefits of targeted treatments. We aim to characterize gynecologic oncology patients referred for somatic tumor genetic mutation testing and assess survival outcomes, efficacy, and toxicities of those receiving targeted therapy. METHODS: We conducted a retrospective chart review of gynecologic oncology patients referred for somatic tumor testing by next generation sequencing between 1/1/2012-8/23/2019. The primary objective was to compare overall and progression free survival between those treated with targeted therapy (group 1) versus traditional treatment (group 2). RESULTS: Most patients (70%) had additional treatment options available based on actionable mutations. The median number of somatic mutations identified was 5 (range 0-53). Patients in group 1 had more actionable somatic mutations (median 2 versus 0, p < 0.001). There was no difference in OS (median 64 versus 76 months, p = 0.97) or PFS (median 2 versus 8 months, p = 0.05) between the groups. While fewer patients in group 1 experienced neuropathy (0 versus 5, p = 0.02), grade I/II thrombocytopenia (7 versus 13, p = 0.03), grade III/IV thrombocytopenia (0 versus 4, p = 0.02), and grade III/IV neutropenia (1 versus 9, p = 0.002), all other non-hematologic toxicities were similar in the two groups. CONCLUSIONS: Most gynecologic cancer patients have actionable mutations and may benefit from a personalized targeted therapy treatment plan. Next generation sequencing can be used to identify clinically actionable mutations in gynecologic cancers and guide the selection of treatments, thereby expanding treatment options without worsening survival or toxicity.

Association of Sickle Cell Trait with Risk and Mortality of COVID-19: Results from the United Kingdom Biobank.

Sickle cell trait (SCT) carriers inherit one copy of the Glu6Val mutation in the hemoglobin gene and is particularly common in Black individuals (5-10%). Considering the roles of hemoglobin in immune responses and the higher risk for coronavirus disease (COVID-19) among Black individuals, we tested whether Black SCT carriers were at increased risk for COVID-19 infection and mortality according to the United Kingdom Biobank. Among Black individuals who were tested for COVID-19, we found similar infection rates among SCT carriers (14/72; 19.7%) and noncarriers (167/791; 21.1%), but higher COVID-19 mortality rates among SCT carriers (4/14; 28.6%) than among noncarriers (21/167; 12.6%) (odds ratio [OR], 3.04; 95% confidence interval [CI], 0.69-11.82; P = 0.12). Notably, SCT carriers with preexisting diabetes had significantly higher COVID-19 mortality (4/4; 100%) than those without diabetes (0/10; 0%; (OR, 90.71; 95% CI, 5.66-infinite; P = 0.0005). These findings suggest that Black SCT carriers with preexisting diabetes are at disproportionally higher risk for COVID-19 mortality. Confirmation by larger studies is warranted.

Double-blind, randomized phase 3 trial of low-dose 13-cis retinoic acid in the prevention of second primaries in head and neck cancer: Long-term follow-up of a trial of the Eastern Cooperative Oncology Group-ACRIN Cancer Research Group (C0590).

BACKGROUND: 13-Cis retinoic acid (13-CRA) is a synthetic vitamin A derivative. High-dose 13-CRA in patients with squamous cell cancers of the head and neck (SCCHNs) reduces the incidence of second primary tumors (SPTs). The authors report long-term results from a phase 3 randomized trial that compared treatment with low-dose 13-CRA versus placebo for patients who had early stage SCCHN, with a focus on the development of SPTs and overall survival (OS). METHODS: In total, 176 patients who received treatment for stage I/II SCCHN were randomized to receive either low-dose 13-CRA (weight-based dose of 7.5 mg or 10 mg) or placebo for 2 years. A competing-risk approach and the log-rank test were used to compare the time to SPT and OS, respectively, between groups. RESULTS: 13-CRA neither significantly reduced the cumulative incidence of SPT (P = .61) nor improved the time to SPT (hazard ratio [HR] for 13-CRA/placebo; 0.86; P = .61). Despite limited power, there was a trend toward improved OS for the 13-CRA arm (HR, 0.75; P = .14), particularly among patients whose index tumor was surgically excised (N = 26; HR, 0.50; P = .057) and among women (N = 39; HR, 0.44; P = .065) and never/former smokers (N = 129; HR, 0.61; P = .055), with a median follow-up of 16 years. The main 13-CRA related toxicities were dry skin and cheilitis. CONCLUSIONS: Treatment with low-dose 13-CRA for 2 years did not decrease the incidence of SPT; subset analysis indicates a potential survival advantage among patients who are women and never/former smokers. More targeted interventions based on clinical risk factors and molecular characterization of tumors may yield greater success in future prevention trials. Cancer 2017;123:4653-4662. © 2017 American Cancer Society.

Germline Mutations in ATM and BRCA1/2 Distinguish Risk for Lethal and Indolent Prostate Cancer and are Associated with Early Age at Death.

BACKGROUND: Germline mutations in BRCA1/2 and ATM have been associated with prostate cancer (PCa) risk. OBJECTIVE: To directly assess whether germline mutations in these three genes distinguish lethal from indolent PCa and whether they confer any effect on age at death. DESIGN, SETTING, AND PARTICIPANTS: A retrospective case-case study of 313 patients who died of PCa and 486 patients with low-risk localized PCa of European, African, and Chinese descent. Germline DNA of each of the 799 patients was sequenced for these three genes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Mutation carrier rates and their effect on lethal PCa were analyzed using the Fisher's exact test and Cox regression analysis, respectively. RESULTS AND LIMITATIONS: The combined BRCA1/2 and ATM mutation carrier rate was significantly higher in lethal PCa patients (6.07%) than localized PCa patients (1.44%), p=0.0007. The rate also differed significantly among lethal PCa patients as a function of age at death (10.00%, 9.08%, 8.33%, 4.94%, and 2.97% in patients who died ≤ 60 yr, 61-65 yr, 66-70 yr, 71-75 yr, and over 75 yr, respectively, p=0.046) and time to death after diagnosis (12.26%, 4.76%, and 0.98% in patients who died ≤ 5 yr, 6-10 yr, and>10 yr after a PCa diagnosis, respectively, p=0.0006). Survival analysis in the entire cohort revealed mutation carriers remained an independent predictor of lethal PCa after adjusting for race and age, prostate-specific antigen, and Gleason score at the time of diagnosis (hazard ratio=2.13, 95% confidence interval: 1.24-3.66, p=0.004). A limitation of this study is that other DNA repair genes were not analyzed. CONCLUSIONS: Mutation status of BRCA1/2 and ATM distinguishes risk for lethal and indolent PCa and is associated with earlier age at death and shorter survival time. PATIENT SUMMARY: Prostate cancer patients with inherited mutations in BRCA1/2 and ATM are more likely to die of prostate cancer and do so at an earlier age.

Implementation of a multidisciplinary pharmacogenomics clinic in a community health system.

PURPOSE: The development and implementation of a multidisciplinary pharmacogenomics clinic within the framework of an established community-based medical genetics program are described. SUMMARY: Pharmacogenomics is an important component of precision medicine that holds considerable promise for pharmacotherapy optimization. As part of the development of a health system-wide integrated pharmacogenomics program, in early 2015 Northshore University Health-System established a pharmacogenomics clinic run by a multidisciplinary team including a medical geneticist, a pharmacist, a nurse practitioner, and genetic counselors. The team identified five key program elements: (1) a billable-service provider, (2) a process for documentation of relevant medication and family histories, (3) personnel with the knowledge required to interpret pharmacogenomic results, (4) personnel to discuss risks, benefits, and limitations of pharmacogenomic testing, and (5) a mechanism for reporting results. The most important program component is expert interpretation of genetic test results to provide clinically useful information; pharmacists are well positioned to provide that expertise. At the Northshore University HealthSystem pharmacogenomics clinic, patient encounters typically entail two one-hour visits and follow a standardized workflow. At the first visit, pharmacogenomics-focused medication and family histories are obtained, risks and benefits of genetic testing are explained, and a test sample is collected; at the second visit, test results are provided along with evidence-based pharmacotherapy recommendations. CONCLUSION: A multidisciplinary clinic providing genotyping and related services can facilitate the integration of pharmacogenomics into clinical care and meet the needs of early adopters of precision medicine.

Promotion of self-management for post treatment cancer survivors: evaluation of a risk-adapted visit.

PURPOSE: The LIFE Cancer Survivorship Program at NorthShore University HealthSystem provides risk-adapted visits (RAV) facilitated by an oncology nurse during which a survivorship care plan (SCP) is provided and discussed. In this report, we describe and evaluate RAV in promoting individualized health care and self-management during survivorship transition. METHODS: Patients complete a post-RAV questionnaire at their RAV and another ≥1 year after their RAV. RESULTS: One thousand seven hundred thirteen (1713) RAVs, majority for breast cancer, occurred from January 2007 to March 2014. One thousand six hundred fifteen (1615) "day-of" post-RAV questionnaires were completed. Respondents scaled statements as strongly agree/agree/disagree/strongly disagree. Combined strongly agree/agree ratings are 94 % felt more confident in communicating information about their treatments to other health care providers, 90 % felt more comfortable recognizing signs/symptoms to report to providers, and 98 % had a better appreciation for community programs/services. Of 488 respondents (RAV January 2007 to December 2012 n = 1366) to a questionnaire at least 1 year after the RAV, nearly 100 % found SCP useful to summarize medical information, 97 % to reinforce follow-up, 85 % to recognize symptoms of recurrence, 93 % to identify healthy lifestyle practices, 91 % to assist in identifying resources for support, 72 % discussed their SCP with their healthcare provider, and 97 % made at least one positive lifestyle change. CONCLUSIONS: Participation in LIFE RAV following treatment helps survivors to guide future self-care behavior. Data suggest that benefits may persist 1 year after the visit and support the feasibility of a nurse-led RAV to establish a SCP in cancer survivors. IMPLICATIONS FOR CANCER SURVIVORS: Combined provision and discussion of SCPs help survivors construct a useful understanding of their cancer experience and may promote long-term self-management.

Direct observation of genomic heterogeneity through local haplotyping analysis.

BACKGROUND: It has been an abiding belief among geneticists that multicellular organisms' genomes can be analyzed under the assumption that a single individual has a uniform genome in all its cells. Despite some evidence to the contrary, this belief has been used as an axiomatic assumption in most genome analysis software packages. In this paper we present observations in human whole genome data, human whole exome data and in mouse whole genome data to challenge this assumption. We show that heterogeneity is in fact ubiquitous and readily observable in ordinary Next Generation Sequencing (NGS) data. RESULTS: Starting with the assumption that a single NGS read (or read pair) must come from one haplotype, we built a procedure for directly observing haplotypes at a local level by examining 2 or 3 adjacent single nucleotide polymorphisms (SNPs) which are close enough on the genome to be spanned by individual reads. We applied this procedure to NGS data from three different sources: whole genome of a Central European trio from the 1000 genomes project, whole genome data from laboratory-bred strains of mouse, and whole exome data from a set of patients of head and neck tumors. Thousands of loci were found in each genome where reads spanning 2 or 3 SNPs displayed more than two haplotypes, indicating that the locus is heterogeneous. We show that such loci are ubiquitous in the genome and cannot be explained by segmental duplications. We explain them on the basis of cellular heterogeneity at the genomic level. Such heterogeneous loci were found in all normal and tumor genomes examined. CONCLUSIONS: Our results highlight the need for new methods to analyze genomic variation because existing ones do not systematically consider local haplotypes. Identification of cancer somatic mutations is complicated because of tumor heterogeneity. It is further complicated if, as we show, normal tissues are also heterogeneous. Methods for biomarker discovery must consider contextual haplotype information rather than just whether a variant "is present".

Breast cancer in postmenopausal women after non-melanomatous skin cancer: the Women's Health Initiative observational study.

An increased risk of breast cancer has been reported in patients with non-melanomatous skin cancer (NMSC), but this association has not been studied in a large, multi-geographic population. We utilized data from the Women's Health Initiative observational study to assess whether history of NMSC is associated with breast cancer risk. This analysis included 70,246 postmenopausal White and Hispanic women aged 50-79, in which 4,247 breast cancer cases were identified over a mean (SD) of 11.3 (3.2) years. Baseline information was collected on demographics, medical history, sun exposure, and vitamin D intake. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95 % confidence intervals (CIs). The relationship between NMSC and breast cancer was examined as a time-dependent exposure using updated information on NMSC gathered during follow-up visits. All statistical tests were two sided. There were 5,595 women diagnosed with NMSC at study entry. The annualized rate of breast cancer was 0.64 % among women with a history of NMSC and 0.55 % among women with no history of NMSC. The multivariable-adjusted HR for breast cancer among women with a history of NMSC versus no history of NMSC was 1.07 (95 % CI 0.95-1.20, P = 0.27). Further evaluation stratified by tumor characteristics showed an increased risk of lymph node-positive disease, HR = 1.30 (95 % CI 1.01-1.67, P = 0.04), and regional-stage disease, HR = 1.33 (95 % CI 1.05-1.70, P = 0.02), among women with NMSC. There was no significant overall association between NMSC and breast cancer; however, there was an increased risk of more advanced-stage breast cancer which needs further exploration.

Implementation of EHR-based strategies to improve outpatient CAD care.

OBJECTIVES: To evaluate the effects of a multifaceted quality improvement intervention during 2 time periods on 4 coronary artery disease [CAD] measures in 4 primary care practices. During the first phase, electronic reminders prompted physicians to order indicated medications or record contraindications and refusals (exceptions). In the second phase, physicians also received reports about their performance (including lists of patients not satisfying these measures), and financial incentives were announced. STUDY DESIGN: Time series analysis. METHODS: Adult CAD patients seen within the preceding 18 months were included. The primary outcome was the performance on each measure (proportion of eligible patients satisfying each measure after removing those with exceptions). Secondary outcomes were the proportion with the medication on their medication list, and the proportion with exceptions. RESULTS: Median performance at baseline was 78.8% for antiplatelet treatment, 85.1% for statin treatment, 77.0% for beta-blocker after myocardial infarction (MI), and 67.1% for angiotensinconverting enzyme inhibitor or angiotensin receptor blocker after MI. Performance improved slightly for 3 measures during the first phase and improved more substantially for all 4 measures during the second phase. For 3 of 4 measures, however, documentation of exceptions increased but not medication prescribing. Most exceptions were judged to be appropriate by peer review. CONCLUSIONS: Physicians responded more to the combination of feedback and financial incentives than they had to electronic reminders alone. High performance was only achieved for 1 of 4 measures and recording of exceptions rather than increases in medication prescribing accounted for most of the observed improvements.

Prospective analysis of association between use of statins and melanoma risk in the Women's Health Initiative.

BACKGROUND: Melanoma is the most lethal form of skin cancer, with an estimated 68,130 new cases and 8700 deaths in the United States in 2010. The increasing incidence and high death rate associated with metastatic disease support the need to focus on prevention. The authors used data from the Women's Health Initiative (WHI) to assess whether 3-hydroxy-3 methylglutaryl coenzyme A inhibitors (statins) are associated with a decreased risk of melanoma. METHODS: The study population consisted of 119,726 postmenopausal white women, in which 1099 cases of malignant melanoma were identified over an average (± standard deviation) of 11.6 ± 3.2 years. All diagnoses were confirmed by medical record review and pathology reports. Information on statin use was collected at baseline and during follow-up. Self-administered and interview-administered questionnaires were used to collect information on other risk factors. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Analyses investigated the association of any statin use, type, potency, lipophilic status, and duration of use with melanoma. RESULTS: Statins were used by 8824 women (7.4%) at baseline. The annualized rate of melanoma was 0.09% among statin users and 0.09% among nonusers The multivariable adjusted HR for statin users compared with nonusers was 1.14 (95% CI, 0.91-1.43). There were no significant differences in risk based on statin type, potency, category, duration, or in time-dependent models. CONCLUSIONS: There was no significant association between statin use and melanoma risk among postmenopausal women in the WHI.

Prospective analysis of association between use of statins or other lipid-lowering agents and colorectal cancer risk.

PURPOSE: To determine whether 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) are associated with a decreased risk of colorectal cancer. METHODS: The population included 159,219 postmenopausal women enrolled in the Women's Health Initiative in which 2000 pathologically confirmed cases of colorectal cancer were identified during an average of 10.7 (S.D. 2.9) years. Information on statins was collected at baseline and years 1, 3, 6, and 9. Self- and interviewer-administered questionnaires were used to collect information on other risk factors. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by the use of Cox proportional hazards regression to evaluate the relationship between statin use and risk. Statistical tests were two-sided. RESULTS: Statins were used by 12,030 (7.6%) women at baseline. The annualized colorectal cancer rate was 0.13% among users and 0.12% among nonusers. The multivariable adjusted HR for users versus nonusers was 0.99 (95% confidence interval [CI], 0.83-1.20, p = .95), and 0.79 (95% CI, 0.56-1.11) for users of ≥3 years. In the multivariable adjusted time-dependent model, the HR for lovastatin was 0.62 (95% CI, 0.39-0.99). There was no effect of tumor location, stage or grade. CONCLUSIONS: There was a reduction in colorectal cancer risk associated with lovastatin and a nonsignificant association with longer duration of use.

Effect of an electronic health record on the culture of an outpatient medical oncology practice in a four-hospital integrated health care system: 5-year experience.

The electronic health record (EHR) was adopted into the NorthShore University HealthSystem, a four-hospital integrated health system located in suburban Chicago, in 2003. By 2005, all chemotherapy and medicine order entry was conducted through the EHR, completing the incorporation of a fully paperless EHR in our hospital-based oncology practice in both the inpatient and outpatient settings. The use of the EHR has dramatically changed our practice environment by improving efficiency, patient safety, research productivity, and operations, while allowing evaluation of adherence to established quality measures and incorporation of new quality improvement initiatives. The reach of the EHR has been substantial and has influenced every aspect of care at our institution over the short period since its implementation. In this article, we describe subjective and objective measures, outcomes, and achievements of our 5-year EHR experience.

Changes in performance after implementation of a multifaceted electronic-health-record-based quality improvement system.

BACKGROUND: Electronic health record (EHR) systems have the potential to revolutionize quality improvement (QI) methods by enhancing quality measurement and integrating multiple proven QI strategies. OBJECTIVES: To implement and evaluate a multifaceted QI intervention using EHR tools to improve quality measurement (including capture of contraindications and patient refusals), make point-of-care reminders more accurate, and provide more valid and responsive clinician feedback (including lists of patients not receiving essential medications) for 16 chronic disease and preventive service measures. DESIGN: Time series analysis at a large internal medicine practice using a commercial EHR. SUBJECTS: All adult patients eligible for each measure (range approximately 100-7500). MEASURES: The proportion of eligible patients who satisfied each measure after removing those with exceptions from the denominator. RESULTS: During the year before the intervention, performance improved significantly for 8 measures. During the year after the intervention, performance improved significantly for 14 measures. For 9 measures, the primary outcome improved more rapidly during the intervention year than during the previous year (P < 0.001 for 8 measures, P = 0.02 for 1). Four other measures improved at rates that were not significantly different from the previous year. Improvements resulted from increases in patients receiving the service, documentation of exceptions, or a combination of both. For 5 drug-prescribing measures, more than half of physicians achieved 100% performance. CONCLUSIONS: Implementation of a multifaceted QI intervention using EHR tools to improve quality measurement and the accuracy and timeliness of clinician feedback improved performance and/or accelerated the rate of improvement for multiple measures simultaneously.

The polycomb group protein BMI1 is a transcriptional target of HDAC inhibitors.

Polycomb group (PcG) proteins are overexpressed in several human malignancies including breast cancer. In particular, aberrant expression of BMI1 and EZH2 has been linked to metastasis and poor prognosis in cancer patients. At present, very little is known about the pharmacological inhibitors of PcG proteins. Here we show that histone deacetylase inhibitors (HDACi) downregulate expression of BMI1. Treatment of MCF10A cells, which are immortal non-transformed breast epithelial cells, and breast cancer cells with HDACi led to decreased expression of BMI1. We further show that downregulation of BMI1 by HDACi results due to the transcriptional downregulation of BMI1 gene. Specifically, we show that primary transcription and promoter activity of BMI1 is suppressed upon treatment with HDACi. Furthermore, downregulation of BMI1 was accompanied by a decrease in histone 2A lysine 119 ubiquitination (H2AK119Ub), which is catalyzed by BMI1 containing polycomb repressive complex 1. HDACi treatment also led to derepression of growth inhibitory genes and putative tumor suppressors, which are known to be silenced by PcG proteins and polycomb repressive complexes (PRCs). In summary, our findings suggest that BMI1 is an important therapy target of HDACi, and that HDACi can be used alone or in combination with other therapies to inhibit growth of tumors that overexpress PcG proteins such as BMI1.

Dietary omega-3 polyunsaturated fatty acids suppress expression of EZH2 in breast cancer cells.

The polycomb group (PcG) protein, enhancer of zeste homologue 2 (EZH2), is overexpressed in several human malignancies including breast cancer. Aberrant expression of EZH2 has been associated with metastasis and poor prognosis in cancer patients. Despite the clear role of EZH2 in oncogenesis and therapy failure, not much is known about chemotherapeutics and chemopreventive agents that can suppress its expression and activity. Here, we show that dietary omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) can regulate the expression of EZH2 in breast cancer cells. The treatment of breast cancer cells with omega-3 PUFAs, but not omega-6 PUFAs, led to downregulation of EZH2. Studies using proteosome inhibitor MG132 suggested that omega-3 PUFAs induce degradation of the PcG protein EZH2 through posttranslational mechanisms. Furthermore, downregulation of EZH2 by omega-3 PUFAs was accompanied by a decrease in histone 3 lysine 27 trimethylation (H3K27me3) activity of EZH2 and upregulation of E-cadherin and insulin-like growth factor binding protein 3, which are known targets of EZH2. Treatment with omega-3 PUFAs also led to decrease in invasion of breast cancer cells, an oncogenic phenotype that is known to be associated with EZH2. Thus, our studies suggest that the PcG protein EZH2 is an important target of omega-3 PUFAs and that downregulation of EZH2 may be involved in the mediation of anti-oncogenic and chemopreventive effects of omega-3 PUFAs.