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1.
Prostate ; 84(3): 292-302, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37964482

ABSTRACT

BACKGROUND: Recently approved treatments and updates to genetic testing recommendations for prostate cancer have created a need for correlated analyses of patient outcomes data via germline genetic mutation status. Genetic registries address these gaps by identifying candidates for recently approved targeted treatments, expanding clinical trial data examining specific gene mutations, and understanding effects of targeted treatments in the real-world setting. METHODS: The PROMISE Registry is a 20-year (5-year recruitment, 15-year follow-up), US-wide, prospective genetic registry for prostate cancer patients. Five thousand patients will be screened through an online at-home germline testing to identify and enroll 500 patients with germline mutations, including: pathogenic or likely pathogenic variants and variants of uncertain significance in genes of interest. Patients will be followed for 15 years and clinical data with real time patient reported outcomes will be collected. Eligible patients will enter long-term follow-up (6-month PRO surveys and medical record retrieval). As a virtual study with patient self-enrollment, the PROMISE Registry may fill gaps in genetics services in underserved areas and for patients within sufficient insurance coverage. RESULTS: The PROMISE Registry opened in May 2021. 2114 patients have enrolled to date across 48 US states and 23 recruiting sites. 202 patients have met criteria for long-term follow-up. PROMISE is on target with the study's goal of 5000 patients screened and 500 patients eligible for long-term follow-up by 2026. CONCLUSIONS: The PROMISE Registry is a novel, prospective, germline registry that will collect long-term patient outcomes data to address current gaps in understanding resulting from recently FDA-approved treatments and updates to genetic testing recommendations for prostate cancer. Through inclusion of a broad nationwide sample, including underserved patients and those unaffiliated with major academic centers, the PROMISE Registry aims to provide access to germline genetic testing and to collect data to understand disease characteristics and treatment responses across the disease spectrum for prostate cancer with rare germline genetic variants.


Subject(s)
Germ-Line Mutation , Prostatic Neoplasms , Male , Humans , Prospective Studies , Prostatic Neoplasms/genetics , Prostatic Neoplasms/therapy , Treatment Outcome , Registries
2.
Eur Urol Oncol ; 2023 Dec 16.
Article in English | MEDLINE | ID: mdl-38105142

ABSTRACT

BACKGROUND AND OBJECTIVE: Checkpoint inhibitor therapy (CPI) has demonstrated survival benefits in urothelial carcinoma (UC); however, not all patients benefit from CPI due to resistance. Combining sitravatinib, a multitargeted receptor tyrosine kinase inhibitor of TYRO3, AXL, and MERTK (TAM) receptors and VEGFR2, with CPI may improve antitumor responses. Our objective was to assess the efficacy and safety of sitravatinib plus nivolumab in patients with advanced/metastatic UC. METHODS: The 516-003 trial (NCT03606174) is an open-label, multicohort phase 2 study evaluating sitravatinib plus nivolumab in patients with advanced/metastatic UC enrolled in eight cohorts depending on prior treatment with CPI, platinum-based chemotherapy (PBC), or antibody-drug conjugate (ADC). Overall, 244 patients were enrolled and treated with sitravatinib plus nivolumab (median follow-up 14.1-38.2 mo). Sitravatinib (free-base capsules 120 mg once daily [QD] or malate capsule 100 mg QD) plus nivolumab (240 mg every 2 wk/480 mg every 4 wk intravenously). KEY FINDINGS AND LIMITATIONS: The primary endpoint was objective response rate (ORR; RECIST v1.1). The secondary endpoints included progression-free survival (PFS) and safety. The Predictive probability design and confidence interval methods were used. Among patients previously treated with PBC, ORR, and median PFS were 32.1% and 3.9 mo in CPI-naïve patients (n = 53), 14.9% and 3.9 mo in CPI-refractory patients (n = 67), and 5.4% and 3.7 mo in CPI- and ADC-refractory patients (n = 56), respectively. Across all cohorts, grade 3 treatment-related adverse events (TRAEs) occurred in 51.2% patients and grade 4 in 3.3%, with one treatment-related death (cardiac failure). Immune-related adverse events occurred in 50.4% patients. TRAEs led to sitravatinib/nivolumab discontinuation in 6.1% patients. CONCLUSIONS AND CLINICAL IMPLICATIONS: Sitravatinib plus nivolumab demonstrated a manageable safety profile but did not result in clinically meaningful ORRs in patients with advanced/metastatic UC in the eight cohorts studied. PATIENT SUMMARY: In this study, the combination of two anticancer drugs, sitravatinib and nivolumab, resulted in manageable side effects but no meaningful responses in patients with bladder cancer.

3.
Cancer Med ; 12(3): 2752-2760, 2023 02.
Article in English | MEDLINE | ID: mdl-36069175

ABSTRACT

BACKGROUND: Urachal carcinoma (UrC) is a rare, aggressive cancer with a poor prognosis that is frequently diagnosed in advanced stages. Due to its rarity, the current staging systems, namely Sheldon, Mayo, and Ontario were established based on relatively small patient cohorts, necessitating further validation. We used a large patient population from the National Cancer Database to model a novel staging system based on the Tumor (T), Node(N), and Metastasis (M) (TNM) staging system and compared it to established staging systems. METHODS: We identified patients diagnosed with UrC between the years of 2004-2016. To determine median overall survival (OS), a Kaplan-Meier (KM) curve was generated using the Sheldon, Mayo, Ontario, and TNM staging system. A cox proportional-hazards regression model was developed to highlight predictors of overall survival. RESULTS: A total of 626 patients were included in the analysis. The OS for the entire cohort was 58.2 months (50.1-67.8) with survival rates at 12, 24, and 60 months of 83%, 70%, and 49%, respectively (p < 0.0001). As compared to the Sheldon, Mayo, and Ontario staging system, our TNM staging system had a more balanced sample and survival distribution per stage and no overlap among stages on KM survival curves. The Mayo, Ontario, and TNM staging systems were more accurate in terms of stage-survival correlation than the Sheldon staging system (p < 0.05 for all stages). CONCLUSIONS: The proposed novel TNM staging system for UrC has a more balanced sample distribution and a more accurate stage-survival correlation than the traditional Mayo, Sheldon, and Ontario staging systems. It is clinically applicable and enables better risk stratification, prognosis, and therapeutic decision-making.


Subject(s)
Urinary Bladder Neoplasms , Humans , Urinary Bladder Neoplasms/pathology , Prognosis , Neoplasm Staging , Proportional Hazards Models , Retrospective Studies
4.
Sci Rep ; 12(1): 18201, 2022 Oct 28.
Article in English | MEDLINE | ID: mdl-36307500

ABSTRACT

We report an improved calculation of the electron backscattering coefficients (BSCs) for beryllium, molybdenum and tungsten at electron energies of 0.1-100 keV based on an up-to-date Monte Carlo simulation method with different input of energy loss function (ELF) data. The electron inelastic cross-section is derived from the relativistic dielectric functional formalism, where the full Penn's algorithm is applied for the extension of the ELF from the optical limit of [Formula: see text] into the [Formula: see text]-plane. We have found that the accuracy of energy loss function may affect largely the calculated BSC. We also show that this has close relationship with the f- and ps-sum rules.

5.
Anticancer Res ; 41(8): 3859-3866, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34281846

ABSTRACT

BACKGROUND: Desmoplastic small round-cell tumor (DSCRT) in adults is an extremely rare (age-adjusted incidence 0.3 per million) and aggressive sarcoma with limited data for optimal management. PATIENTS AND METHODS: Retrospective analysis of patients with DSCRT diagnosis (2010-2020) was performed following Institutional Review Board approval. The follow-up period was from pathological diagnosis to the last patient contact. Endpoints were type of response and duration of response. RESULTS: In the current analysis, first-line treatment in all cases was vincristine, anthracycline, and cyclophosphamide alternating with ifosfamide and etoposide (VAC-IE) with 100% response for a mean duration of 9.8 (range=5-12) months. Patients received 1-4 subsequent lines of therapy. All patients received temozolomide with irinotecan (50% partial response, duration 8-9 months). Two patients that underwent consolidative cytoreductive surgery with hyperthermic intraperitoneal chemotherapy had a longer survival (30.6 vs. 11.2 months). Patients suffered 100% mortality with a median survival was 17.8 (range=11.2-30.6) months. CONCLUSION: While aggressive multimodality treatment is always warranted for DSCRT, the options are limited by the multicentric presentation, short-lived initial response and lack of established subsequent therapy portending a poor prognosis. Consolidative cytoreductive surgery following first-line therapy may improve survival.


Subject(s)
Desmoplastic Small Round Cell Tumor/therapy , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Cytoreduction Surgical Procedures , Desmoplastic Small Round Cell Tumor/mortality , Desmoplastic Small Round Cell Tumor/pathology , Humans , Hyperthermic Intraperitoneal Chemotherapy/methods , Male , Molecular Targeted Therapy/methods
6.
J Clin Oncol ; 39(12): 1371-1382, 2021 04 20.
Article in English | MEDLINE | ID: mdl-33617303

ABSTRACT

PURPOSE: Prostate cancer (PCa) becomes resistant to androgen ablation through adaptive upregulation of the androgen receptor in response to the low-testosterone microenvironment. Bipolar androgen therapy (BAT), defined as rapid cycling between high and low serum testosterone, disrupts this adaptive regulation in castration-resistant PCa (CRPC). METHODS: The TRANSFORMER (Testosterone Revival Abolishes Negative Symptoms, Fosters Objective Response and Modulates Enzalutamide Resistance) study is a randomized study comparing monthly BAT (n = 94) with enzalutamide (n = 101). The primary end point was clinical or radiographic progression-free survival (PFS); crossover was permitted at progression. Secondary end points included overall survival (OS), prostate-specific antigen (PSA) and objective response rates, PFS from randomization through crossover (PFS2), safety, and quality of life (QoL). RESULTS: The PFS was 5.7 months for both arms (hazard ratio [HR], 1.14; 95% CI, 0.83 to 1.55; P = .42). For BAT, 50% decline in PSA (PSA50) was 28.2% of patients versus 25.3% for enzalutamide. At crossover, PSA50 response occurred in 77.8% of patients crossing to enzalutamide and 23.4% to BAT. The PSA-PFS for enzalutamide increased from 3.8 months after abiraterone to 10.9 months after BAT. The PFS2 for BAT→enzalutamide was 28.2 versus 19.6 months for enzalutamide→BAT (HR, 0.44; 95% CI, 0.22 to 0.88; P = .02). OS was 32.9 months for BAT versus 29.0 months for enzalutamide (HR, 0.95; 95% CI, 0.66 to 1.39; P = .80). OS was 37.1 months for patients crossing from BAT to enzalutamide versus 30.2 months for the opposite sequence (HR, 0.68; 95% CI, 0.36 to 1.28; P = .225). BAT adverse events were primarily grade 1-2. Patient-reported QoL consistently favored BAT. CONCLUSION: This randomized trial establishes meaningful clinical activity and safety of BAT and supports additional study to determine its optimal clinical integration. BAT can sensitize CRPC to subsequent antiandrogen therapy. Further study is required to confirm whether sequential therapy with BAT and enzalutamide can improve survival in men with CRPC.


Subject(s)
Benzamides/therapeutic use , Nitriles/therapeutic use , Phenylthiohydantoin/therapeutic use , Prostatic Neoplasms, Castration-Resistant/drug therapy , Testosterone/analogs & derivatives , Aged , Aged, 80 and over , Asymptomatic Diseases , Cross-Over Studies , Humans , Male , Middle Aged , Neoplasm Metastasis , Prostate-Specific Antigen/blood , Prostatic Neoplasms, Castration-Resistant/blood , Prostatic Neoplasms, Castration-Resistant/mortality , Prostatic Neoplasms, Castration-Resistant/psychology , Quality of Life , Receptors, Androgen/analysis , Testosterone/blood , Testosterone/therapeutic use
7.
Adv Radiat Oncol ; 5(1): 85-91, 2020.
Article in English | MEDLINE | ID: mdl-32051894

ABSTRACT

PURPOSE: Surgery is the standard-of-care treatment in patients with localized renal cell carcinoma (RCC), offering excellent chance of cure. However, there is a subset of patients who are ineligible for surgery and instead manage with ablative therapies, such as stereotactic ablative body radiation therapy (SABR). We used the National Cancer Database to examine trends in the use of SABR for inoperable RCC and identify any predictors of outcome. METHODS AND MATERIALS: We queried the National Cancer Database for patients with unresected RCC between 2004 and 2016 who were treated with SABR. Kaplan-Meier analyses were used to determine overall survival. Multivariable Cox regression was used to identify predictors of survival. RESULTS: We identified 347 patients meeting eligibility criteria. Median age was 74, and the majority of patients were clinical stage T1-2 (80%) and N0 (97%). The median tumor size was 3.8 cm (interquartile range [IQR], 2.8-5.2 cm). Six percent of patients received systemic therapy. The median dose of SABR was 45 Gy (IQR, 35-54 Gy) in 3 fractions (IQR, 1-5 fractions). The median follow-up was 36 months (IQR, 1-156 months). Predictors of decreased survival were age >74, larger tumors, and N1 or M1 disease. Median survival across the entire cohort was 58 months. Median survival was 92 months, 88 months, 44 months, and 26 months for primary tumors ≤2.5 cm, 2.6-3.5 cm, 3.5-5.0 cm, and >5.0 cm, respectively (P < .0001). CONCLUSIONS: SABR is being increasingly used for renal cell carcinoma across the United States with excellent outcomes in smaller tumors.

8.
Prostate ; 79(12): 1457-1461, 2019 09.
Article in English | MEDLINE | ID: mdl-31294484

ABSTRACT

BACKGROUND: Small cell carcinoma (SCC) of the prostate is a rare, aggressive disease. Evidence is limited; however, the current standard of care is chemotherapy. The benefit of local treatment modalities is unknown. METHODS: We queried the National Cancer Database identifying all SCC/neuroendocrine cases of the prostate, excluding those with unknown nodal or metastatic status, unknown treatment, or those not receiving chemotherapy. Overall survival (OS) was calculated using Kaplan-Meier curves. Multivariable Cox proportional hazards model was used to identify factors associated with survival. A further subgroup analysis was performed on the utility of local therapy on survival in the nonmetastatic setting. RESULTS: Our final cohort included 657 patients with a median age of 68. Most patients had positive lymph nodes (60.1%) and metastatic disease (70.0%). Median survival was 12 months (95% confidence interval [95% CI], 11.1-13.3 months) with a median follow-up of 11.8 months. Metastatic disease, age greater than or equal to 70, omission of androgen deprivation therapy (ADT), and lower income (P < .05 for all) were all associated with reduced OS. Patients with prostate-specific antigen (PSA) greater than or equal to 33 ng/mL and those receiving ADT had better survival (P < .05). Those with nonmetastatic disease were more likely to undergo prostatectomy and/or prostatic/pelvic radiation (P < .0001). Prostatic/pelvic radiation in the nonmetastatic setting was associated with longer survival (P = .02). Though well powered, our study is limited by the selection bias inherent to all observational studies, despite the statistical methods utilized to reduce this effect. CONCLUSIONS: Although chemotherapy is the mainstay of treatment, radiation to the prostate/pelvis may be beneficial in the nonmetastatic setting. In addition to chemotherapy, ADT may benefit patients with an elevated PSA.


Subject(s)
Carcinoma, Small Cell/epidemiology , Carcinoma, Small Cell/therapy , Neuroendocrine Tumors/epidemiology , Neuroendocrine Tumors/therapy , Prostatic Neoplasms/epidemiology , Prostatic Neoplasms/therapy , Adult , Aged , Aged, 80 and over , Carcinoma, Small Cell/mortality , Databases, Factual , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Neuroendocrine Tumors/mortality , Prostatic Neoplasms/mortality , Treatment Outcome , United States/epidemiology
9.
Phys Rev E ; 97(1-1): 012221, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29448422

ABSTRACT

Currently, effective phonons (renormalized or interacting phonons) rather than solitary waves (for short, solitons) are regarded as the energy carriers in nonlinear lattices. In this work, by using the approximate soliton solutions of the corresponding equations of motion and adopting the Boltzmann distribution for these solitons, the average velocities of solitons are obtained and are compared with the sound velocities of energy transfer. Excellent agreements with the numerical results and the predictions of other existing theories are shown in both the symmetric Fermi-Pasta-Ulam-ß lattices and the asymmetric Fermi-Pasta-Ulam-αß lattices. These clearly indicate that solitons are suitable candidates for energy carriers in Fermi-Pasta-Ulam lattices. In addition, the root-mean-square velocity of solitons can be obtained from the effective phonons theory.

10.
Int J Cancer ; 143(1): 113-126, 2018 07 01.
Article in English | MEDLINE | ID: mdl-29396848

ABSTRACT

Chronic arsenic exposure is associated with the development of urothelial carcinoma of the bladder (UCB). To elucidate the contribution of arsenic exposure to urothelial cancer stem cell (CSC) generation, we established an in vitro stepwise malignant model transformed by chronically exposing human urothelial cells to arsenic. Using this model, we found that chronic arsenic exposure endows urothelial cells with malignant stemness properties including increased expression of stemness-related factors such as SOX2, sphere formation, self-renewal, invasion and chemoresistance. SOX2 was gradually and irreversibly overexpressed in line with acquired sphere-forming and self-renewal abilities. Following gene set enrichment analyses of arsenic-exposed and arsenic-unexposed cells, we found COX2 as an enriched gene for oncogenic signature. Mechanistically, arsenic-induced COX2/PGE2 increases SOX2 expression that eventually promotes malignant stem cell generation and repopulation. In urine samples from 90 subjects exposed to arsenic and 91 control subjects, we found a significant linear correlation between SOX2 and COX2 expression and the potential of SOX2 and COX2 expression as urinary markers to detect subjects exposed to arsenic. Furthermore, the combination marker yielded a high sensitivity for UCB detection in a separate cohort. Finally, our in vitro model exhibits basal-type molecular features and dual inhibition of EGFR and COX2 attenuated stem cell enrichment more efficiently than an EGFR inhibitor alone. In conclusion, the COX2/PGE2-SOX2 axis promotes arsenic-induced malignant stem cell transformation. In addition, our findings indicate the possible use of SOX2 and COX2 expression as urinary markers for the risk stratification and detection of UCB.


Subject(s)
Arsenic/toxicity , Cell Transformation, Neoplastic/chemically induced , Cyclooxygenase 2/genetics , Dinoprostone/metabolism , SOXB1 Transcription Factors/genetics , Urothelium/cytology , Biomarkers, Tumor/urine , Cell Line, Tumor , Cell Proliferation , Cell Survival , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/metabolism , Cyclooxygenase 2/metabolism , Cyclooxygenase 2/urine , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Neoplastic Stem Cells/drug effects , Neoplastic Stem Cells/metabolism , SOXB1 Transcription Factors/metabolism , SOXB1 Transcription Factors/urine , Up-Regulation , Urothelium/drug effects , Urothelium/metabolism
11.
Cancer Res ; 78(1): 168-181, 2018 01 01.
Article in English | MEDLINE | ID: mdl-29180467

ABSTRACT

Overcoming acquired drug resistance remains a core challenge in the clinical management of human cancer, including in urothelial carcinoma of the bladder (UCB). Cancer stem-like cells (CSC) have been implicated in the emergence of drug resistance but mechanisms and intervention points are not completely understood. Here, we report that the proinflammatory COX2/PGE2 pathway and the YAP1 growth-regulatory pathway cooperate to recruit the stem cell factor SOX2 in expanding and sustaining the accumulation of urothelial CSCs. Mechanistically, COX2/PGE2 signaling induced promoter methylation of let-7, resulting in its downregulation and subsequent SOX2 upregulation. YAP1 induced SOX2 expression more directly by binding its enhancer region. In UCB clinical specimens, positive correlations in the expression of SOX2, COX2, and YAP1 were observed, with coexpression of COX2 and YAP1 particularly commonly observed. Additional investigations suggested that activation of the COX2/PGE2 and YAP1 pathways also promoted acquired resistance to EGFR inhibitors in basal-type UCB. In a mouse xenograft model of UCB, dual inhibition of COX2 and YAP1 elicited a long-lasting therapeutic response by limiting CSC expansion after chemotherapy and EGFR inhibition. Our findings provide a preclinical rationale to target these pathways concurrently with systemic chemotherapy as a strategy to improve the clinical management of UCB.Significance: These findings offer a preclinical rationale to target the COX2 and YAP1 pathways concurrently with systemic chemotherapy to improve the clinical management of UCB, based on evidence that these two pathways expand cancer stem-like cell populations that mediate resistance to chemotherapy. Cancer Res; 78(1); 168-81. ©2017 AACR.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Cyclooxygenase 2/metabolism , Neoplastic Stem Cells/metabolism , Phosphoproteins/metabolism , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/pathology , Adaptor Proteins, Signal Transducing/genetics , Animals , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Cisplatin/administration & dosage , Cyclooxygenase 2/genetics , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Drug Resistance, Neoplasm/drug effects , Gene Expression Regulation, Neoplastic , Humans , Mice, Nude , Neoplastic Stem Cells/pathology , Phosphoproteins/genetics , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism , Transcription Factors , Urinary Bladder Neoplasms/metabolism , Urothelium/pathology , Xenograft Model Antitumor Assays , YAP-Signaling Proteins , Gemcitabine
12.
Article in English | MEDLINE | ID: mdl-29079164

ABSTRACT

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

14.
Prostate ; 67(15): 1677-85, 2007 Nov 01.
Article in English | MEDLINE | ID: mdl-17879948

ABSTRACT

BACKGROUND: Because neither continuous nor intermittent hormonal therapy is curative, we designed a clinical model to screen new drugs for additive or synergistic effects with hormonal therapy and used IM862, a naturally occurring dipeptide with antiangiogenic and immunomodulatory properties, to test it. METHODS: Patients with prostate cancer who had rising PSA levels after radical prostatectomy and/or radiation therapy were given combined androgen ablation for 3 months. After 2 months' treatment, patients were randomly assigned in a double-blind fashion to receive intranasal IM862 or placebo daily. Treatment continued for 6 months or until disease progression, which was defined by a rising serum PSA level, the appearance of new skeletal or extraskeletal metastatic disease, or new symptoms requiring intervention. RESULTS: Seventy-one patients were evaluable for response. Median time to PSA progression was not reached in either group. At 6 months, disease had progressed in 14 (41%) of the 34 patients receiving treatment and 18 (49%) of the 37 receiving placebo (P = 0.39). No significant toxicities emerged. CONCLUSIONS: The model was demonstrated to be an efficient platform for new drug screening; however, IM862, though well tolerated, failed to demonstrate superiority over placebo in prolonging time to PSA progression.


Subject(s)
Adenocarcinoma/therapy , Adjuvants, Immunologic/therapeutic use , Androgen Antagonists/therapeutic use , Angiogenesis Inhibitors/therapeutic use , Dipeptides/therapeutic use , Prostatic Neoplasms/therapy , Adenocarcinoma/blood , Adenocarcinoma/diagnosis , Adjuvants, Immunologic/administration & dosage , Administration, Intranasal , Angiogenesis Inhibitors/administration & dosage , Antineoplastic Agents, Hormonal/therapeutic use , Combined Modality Therapy , Dipeptides/administration & dosage , Disease Progression , Double-Blind Method , Drug Administration Schedule , Humans , Male , Neoplasm Recurrence, Local/drug therapy , Prostatic Neoplasms/blood , Prostatic Neoplasms/diagnosis , Treatment Outcome
15.
Mol Cell Biol ; 26(8): 3114-23, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16581786

ABSTRACT

MEF is an ETS-related transcription factor with strong transcriptional activating activity that affects hematopoietic stem cell behavior and is required for normal NK cell and NK T-cell development. The MEF (also known as ELF4) gene is repressed by several leukemia-associated fusion transcription factor proteins (PML-retinoic acid receptor alpha and AML1-ETO), but it is also activated by retroviral insertion in several cancer models. We have previously shown that cyclin A-dependent phosphorylation of MEF largely restricts its activity to the G(1) phase of the cell cycle; we now show that MEF is a short-lived protein whose expression level also peaks during late G(1) phase. Mutagenesis studies show that the rapid turnover of MEF in S phase is dependent on the specific phosphorylation of threonine 643 and serine 648 at the C terminus of MEF by cdk2 and on the Skp1/Cul1/F-box (SCF) E3 ubiquitin ligase complex SCF(Skp2), which targets MEF for ubiquitination and proteolysis. Overexpression of MEF drives cells through the G(1)/S transition, thereby promoting cell proliferation. The tight regulation of MEF levels during the cell cycle contributes to its effects on regulating cell cycle entry and cell proliferation.


Subject(s)
DNA-Binding Proteins/metabolism , Ligases/metabolism , Proteins/metabolism , Transcription Factors/metabolism , Ubiquitin/metabolism , Amino Acid Sequence , Cell Line , Cell Line, Tumor , Cysteine Proteinase Inhibitors/pharmacology , DNA-Binding Proteins/analysis , DNA-Binding Proteins/chemistry , Gene Expression Regulation , Half-Life , Humans , Hydrolysis , Leupeptins/pharmacology , Ligases/genetics , Mutagenesis, Site-Directed , Phosphorylation , Proteins/genetics , Serine/metabolism , Threonine/metabolism , Transcription Factors/analysis , Transcription Factors/chemistry , Ubiquitin/analysis
16.
Immunity ; 17(4): 437-49, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12387738

ABSTRACT

We utilized gene targeting by homologous recombination to define the role that MEF, a transcriptional activating member of the ETS family of transcription factors, plays in lymphopoiesis. MEF-/- mice have a profound reduction in the number of NK-T and NK cells. Purified MEF-/- NK cells cannot lyse tumor cell targets and secrete only minimal amounts of IFNgamma. Perforin protein expression is severely impaired in MEF-deficient NK cells, likely accounting for the lack of tumor cell cytotoxicity. Promoter studies and chromatin immunoprecipitation analyses demonstrate that MEF and not ETS-1 directly regulates transcription of the perforin gene in NK cells. Our results uncover a specific role of MEF in the development and function of NK cells and in innate immunity.


Subject(s)
DNA-Binding Proteins/physiology , Killer Cells, Natural/immunology , Membrane Glycoproteins/genetics , T-Lymphocyte Subsets/immunology , Transcription Factors/physiology , Animals , B-Lymphocytes/immunology , Cytotoxicity, Immunologic , DNA-Binding Proteins/deficiency , DNA-Binding Proteins/genetics , Gene Expression Regulation , In Vitro Techniques , Lymphocytes/pathology , Lymphopoiesis , Mice , Mice, Knockout , Perforin , Pore Forming Cytotoxic Proteins , Promoter Regions, Genetic , Transcription Factors/deficiency , Transcription Factors/genetics
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