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1.
J Chin Med Assoc ; 86(11): 1001-1007, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37643918

RESUMO

BACKGROUND: The majority of patients diagnosed with early stage endometrial cancer have a favorable prognosis; however, approximately 10% to 15% experience a recurrence. Therefore, the aim of the present study was to evaluate whether postoperative carbohydrate antigen 125 (CA-125) levels could be used to predict recurrence and recurrence-free survival (RFS) in patients with surgical stage I endometrial cancer. METHODS: We enrolled a total of 518 patients with stage I endometrial cancer who underwent surgical treatment between January 2010 and March 2019. Serum CA-125 levels were measured prior to surgery, as well as 6 to 12 months after surgery. Subsequently, the correlations between the CA-125 levels, cancer recurrence, and RFS were analyzed. RESULTS: Although the preoperative CA-125 level was not associated with the risk of cancer recurrence, the postoperative CA-125 level was found to be the only independent predictor of recurrence in both univariate and multivariate analyses. Additionally, we found that a postoperative CA-125 cutoff value of 13.75 U/mL yielded the best sensitivity and specificity for predicting cancer recurrence. Patients with a postoperative CA-125 level ≥13.75 U/mL, and those with a level <13.75 U/mL, had a median time to recurrence and a 5-year RFS rate of 35.5 vs 50.5 months and 84.7 vs 94.4%, respectively. Additionally, postoperative CA-125 levels were not found to be correlated with preoperative levels. CONCLUSION: In patients with stage I endometrial cancer, a postoperative CA-125 level ≥13.75 U/mL was found to be significantly correlated with a higher recurrence rate, as well as a shorter RFS. Therefore, obtaining a follow-up CA-125 level within 6 to 12 months after staging surgery may be a promising noninvasive biomarker for predicting recurrence.


Assuntos
Neoplasias do Endométrio , Recidiva Local de Neoplasia , Feminino , Humanos , Estadiamento de Neoplasias , Prognóstico , Neoplasias do Endométrio/patologia , Antígeno Ca-125 , Estudos Retrospectivos
2.
J Chin Med Assoc ; 86(4): 418-425, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36859778

RESUMO

BACKGROUND: This study aimed to evaluate the anatomic and clinical outcomes of robot-assisted sacrohysteropexy (RASH) against robot-assisted sacrocolpopexy (RASC) for the treatment of primary advanced apical prolapse. METHODS: We conducted a retrospective cohort study of all robot-assisted pelvic organ prolapse surgeries for primary advanced apical prolapse (stage ≥II) between January 2011 and May 2021 at an academic tertiary hospital. Surgical outcomes and pelvic organ function were evaluated using the Pelvic Organ Prolapse Quantitative (POP-Q) stage and validated questionnaires (POPDI-6) during preoperative and postoperative 12-month follow-up evaluations. All data were obtained from electronic medical records. RESULTS: A total of 2368 women underwent surgery for apical prolapse repair, and 18 women underwent either RASH (n = 11) or RASC (n = 7). Compared to the RASC group, the RASH group was significantly younger, premenopausal, and less parous. Preoperative prolapse stage, operative time, estimated blood loss, and hospitalization length was comparable between the groups. No intraoperative complications were observed. All women had a median follow-up duration of 24 months (range: 12-108 months). During the 12-month follow-up period, women in the RASH group reported higher satisfaction with the surgery than those in the RASC group (100% vs. 71.4%, p = 0.137). The mesh exposure rate was significantly higher in the RASC group (3/7, 42.9%) than in the RASH group (0/11, 0%) ( p = 0.043), which was found at 12 to 36 months postoperatively and was successfully managed with vaginal estrogen cream. In the RASH group, one woman required reoperation with anterior colporrhaphy for recurrent anterior prolapse at 60 months postoperatively. The apical success rate was 100% at one year postoperatively, without apical recurrence in either group during the follow-up period. CONCLUSION: RASH represents an effective and feasible option for the surgical treatment of advanced primary apical prolapse in women who desire uterine preservation and have a significantly lower risk of mesh erosion than RASC.


Assuntos
Prolapso de Órgão Pélvico , Procedimentos Cirúrgicos Robóticos , Robótica , Feminino , Humanos , Estudos Retrospectivos , Resultado do Tratamento , Prolapso de Órgão Pélvico/cirurgia
3.
Int J Gynaecol Obstet ; 161(3): 751-759, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36527263

RESUMO

OBJECTIVE: To investigate the safety and efficacy of adjuvant gonadotropin-releasing hormone agonist (GnRH-a) treatment followed by maintenance dienogest (DNG) therapy after uterus-sparing surgery. METHODS: Retrospective cohort study. A total of 190 patients with severe adenomyosis underwent uterus-sparing surgery between January 2010 and June 2020. Of these patients, 90 were analyzed. Forty-six patients (control group) received adjuvant 6-month GnRH-a therapy alone after uterus-sparing surgery, and 44 patients (maintenance group) received postoperative 6-month GnRH-a treatment followed by maintenance DNG therapy (2 mg/day orally). The median follow-up period was 18 months. The study was analyzed using generalized estimating equations. RESULTS: At baseline, the characteristics of patients in each group were comparable. Compared with the control group, the maintenance group had a significant improvement in the visual analog scale score of dysmenorrhea (P < 0.001), hemoglobin level (P = 0.004), and uterine volume (P = 0.004) from baseline to 18 months after uterus-sparing surgery. The symptom recurrence rate was significantly lower in the maintenance group than in the control group (4.6% vs. 37.0%, P < 0.001). CONCLUSIONS: The findings of this study suggest that combinatorial treatment with GnRH-a (adjuvant treatment) and DNG (maintenance therapy) represents a safe and effective short-term therapy after uterus-sparing surgery for adenomyosis.


Assuntos
Adenomiose , Feminino , Humanos , Adenomiose/tratamento farmacológico , Adenomiose/cirurgia , Hormônio Liberador de Gonadotropina , Estudos Retrospectivos , Útero/cirurgia
4.
Am J Surg Pathol ; 47(1): 124-130, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36221308

RESUMO

Ovarian clear cell carcinoma (OCCC), a chemoresistant ovarian cancer, shows a modest response to anti-programmed death-1/programmed death ligand-1 (PD-1/PD-L1) therapies. The effects of anti-PD-1/PD-L1 therapies rely on cytotoxic T-cell response, which is triggered by antigen presentation mediated by major histocompatibility complex (MHC) class I. The loss of MHC class I with simultaneous PD-L1 expression has been noted in several cancer types; however, these findings and their prognostic value have rarely been evaluated in OCCC. We collected data from 76 patients with OCCC for clinicopathologic analysis. Loss of MHC class I expression was seen in 44.7% of the cases including 39.3% to 47.4% of the PD-L1 + cases and was associated with fewer CD8 + tumor-infiltrating lymphocytes (TILs). PD-L1 positivity was associated with a higher number of CD8 + TILs. Cox proportional hazard models showed that high (≥50/mm 2 ) CD8 + TILs was associated with shorter disease-specific survival (hazard ratio [HR]=3.447, 95% confidence interval [CI]: 1.222-9.720, P =0.019) and overall survival (HR=3.053, 95% CI: 1.105-8.43, P =0.031). PD-L1 positivity using Combined Positive Score was associated with shorter progression-free survival (HR=3.246, 95% CI: 1.435-7.339, P =0.005), disease-specific survival (HR=4.124, 95% CI: 1.403-12.116, P =0.010), and overall survival (HR=4.489, 95% CI: 1.553-12.972, P =0.006). Loss of MHC class I may contribute to immune evasion and resistance to anti-PD-1/PD-L1 therapies in OCCC, and CD8 + TILs and PD-L1 positivity using Combined Positive Score may have a negative prognostic value.


Assuntos
Adenocarcinoma de Células Claras , Antígeno B7-H1 , Neoplasias Ovarianas , Feminino , Humanos , Adenocarcinoma de Células Claras/patologia , Antígeno B7-H1/análise , Linfócitos T CD8-Positivos , Linfócitos do Interstício Tumoral , Complexo Principal de Histocompatibilidade , Prognóstico , Neoplasias Ovarianas/patologia
5.
Eur Radiol ; 32(11): 7854-7864, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35583711

RESUMO

OBJECTIVE: This study aimed to compare the ability of the O-RADS and ADNEX models to classify benign or malignant adnexal lesions. METHODS: This retrospective single-center study included women who underwent surgery for adnexal lesions. Two gynecologists independently categorized the adnexal lesions according to the O-RADS and ADNEX models. Four additional readers were included to validate the new quick-access O-RADS flowchart. RESULTS: Among the 322 patients included in this study, 264 (82.0%) had a benign diagnosis, and 58 (18.0%) had a malignant diagnosis. The malignant rates of O-RADS 2, O-RADS 3, O-RADS 4, and O-RADS 5 were 0%, 3.0%, 37.7%, and 78.9%, respectively. The AUC of the O-RADS in the 322 patients was 0.93. On comparing the O-RADS and ADNEX models in the remaining 281 patients, the AUCs of the O-RADS, ADNEX model with CA125, and ADNEX model without CA125 were 0.92, 0.95, and 0.94, respectively. When setting a uniform cutoff of ≥ 10% (≥ O-RADS 4) to predict malignancy, the O-RADS had higher sensitivity than the ADNEX model (96.6% vs. 91.4%), and relatively similar specificity. In addition, the readers with the quick-access flowchart spent less time categorizing O-RADS than the readers with only the original O-RADS table (mean analysis time: 99 min 15 s vs. 111 min 55 s). CONCLUSIONS: The O-RADS classification of the adnexal lesions as benign or malignant was comparable to that of the ADNEX model and had higher sensitivity at the 10% cutoff value. A quick-access O-RADS flowchart was helpful in O-RADS categorization and might shorten the analysis time. KEY POINTS: • Both O-RADS and ADNEX models had good diagnostic performance in distinguishing adnexal malignancy, and O-RADS had higher sensitivity than ADNEX model in uniform 10% cutoff to predict malignancy. • Quick-access O-RADS flowchart was developed to help review O-RADS classification and might help reduce the analysis time.


Assuntos
Doenças dos Anexos , Neoplasias Ovarianas , Humanos , Feminino , Doenças dos Anexos/diagnóstico por imagem , Doenças dos Anexos/patologia , Estudos Retrospectivos , Neoplasias Ovarianas/patologia , Ultrassonografia , Anexos Uterinos/patologia , Sensibilidade e Especificidade
6.
BMJ Case Rep ; 15(4)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35396236

RESUMO

Primary vaginal neuroendocrine tumours are extremely rare but aggressive. We report a case of primary poorly differentiated vaginal carcinoma with focal neuroendocrine differentiation. The clinical stage was cT3N1M0, FIGO stage III. The patient received six cycles of cisplatin-based concurrent chemoradiation therapy (CCRT) followed by six cycles of adjuvant chemotherapy (IEP protocol: ifosfomide, epirubicin and cisplatin). Pelvic MRI scans obtained after treatment completion revealed no residual tumour in the vagina. However, the patient experienced severe dyspnoea 2 months later. Chest X-ray revealed a reticulonodular interstitial pattern over bilateral lungs with suspicion of lymphangitic carcinomatosis. Further chest, abdominal and pelvic CT scans showed bilateral lung metastases with multiple mediastinal, left lower neck and left axilla, intra-abdominal and pelvic lymphadenopathies. For this rare tumour, cisplatin-based CCRT followed by IEP protocol adjuvant chemotherapy may have a limited treatment effect. Further studies are necessary to provide more information on clinical management.


Assuntos
Carcinoma Neuroendócrino , Neoplasias Epiteliais e Glandulares , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Neuroendócrino/diagnóstico por imagem , Carcinoma Neuroendócrino/tratamento farmacológico , Quimiorradioterapia , Quimioterapia Adjuvante , Cisplatino/uso terapêutico , Feminino , Humanos , Estadiamento de Neoplasias , Neoplasias Epiteliais e Glandulares/patologia , Vagina/patologia
7.
J Minim Invasive Gynecol ; 29(5): 602-612, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35123042

RESUMO

OBJECTIVE: To evaluate the efficacy of different hormone therapies in preventing postoperative endometrioma recurrence. DATA SOURCES: The MEDLINE, COCHRANE, and Embase electronic databases were searched from inception to 30 April 2021. METHODS OF STUDY SELECTION: Randomized controlled trials (RCTs) or cohort studies including reproductive age women with endometriosis undergoing ovarian cystectomy or excision of endometriotic lesions compared the effects of postoperative adjuvant therapy (gonadotropin-releasing hormone agonist [GnRHa]) and postoperative maintenance hormone interventions for more than 1 year (i.e., oral contraceptive pills [OCPs], dienogest [DNG], levonorgestrel-releasing intrauterine system [LNGIUS]) on endometrioma recurrence. TABULATION, INTEGRATION, AND RESULTS: Data collection and analysis of the data were independently performed 2 two reviewers. A total of 11 studies were included, of which 2 were RCTs, and 9 were cohort studies. There were 2394 patients with 6 interventions (cases: 1665, 69.6%) and expectant management (cases: 729, 30.4%). Relative treatment effects were estimated using network meta-analysis and ranked in descending order. The clinical effectiveness of these drugs (vs expectant management) was as follows: GnRHa plus DNG (odds ratio [OR], 0.04; 95% confidence interval [CI], 0.01-0.27), surface under the cumulative ranking (SUCRA) = 94.0; DNG (OR, 0.11; 95% CI, 0.04-0.32), SUCRA = 69.7; GnRHa plus OCP (OR, 0.12; 95% CI, 0.02-0.64), SUCRA = 63.4; GnRHa plus LNGIUS (OR, 0.13; 95% CI, 0.03-0.66), SUCRA = 59.4; and OCP (OR, 0.21; 95% CI, 0.13-0.36), SUCRA = 43.6. The effectiveness of GnRHa (OR, 0.47; 95% CI, 0.12-1.89), SUCRA = 17.3 was not significantly different from that of controls. CONCLUSION: In network meta-analysis, combined postoperative adjuvant therapy and longer maintenance hormone treatment are better than a single agent in preventing postoperative endometrioma recurrence. GnRHa plus DNG maintenance treatment might be the most effective intervention. Large-scale RCTs of these agents are still required.


Assuntos
Endometriose , Anticoncepcionais Orais Combinados/uso terapêutico , Endometriose/tratamento farmacológico , Endometriose/prevenção & controle , Endometriose/cirurgia , Feminino , Humanos , Metanálise em Rede , Ovariectomia , Período Pós-Operatório
8.
J Minim Invasive Gynecol ; 29(4): 519-527, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34902596

RESUMO

STUDY OBJECTIVE: To compare the safety, efficacy, and adverse events of the new mini-adjustable sling system "I-stop-mini" with transobturator midurethral slings "Obtryx" (Boston Scientific, Marlborough, MA) in women with stress urinary incontinence. DESIGN: A single-center, retrospective cohort study. SETTING: Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taiwan. PATIENTS: A total of 347 patients who underwent I-stop-mini or Obtryx for stress urinary incontinence treatment. INTERVENTIONS: Midurethral sling with either I-stop-mini or Obtryx. MEASUREMENTS AND MAIN RESULTS: The primary outcomes were objective success and subjective cure rates between the 2 groups. Objective success was evaluated using a 1-hour pad test, and subjective cure was evaluated using a questionnaire score (Incontinence Impact Questionnaire, Urinary Distress Inventory, and International Consultation on Incontinence Questionnaire Short Form). Secondary outcomes were the evaluation of surgical outcomes, operative data, and adverse events between the 2 groups. In total, 171 of 200 I-stop-mini subjects and 127 of 147 Obtryx subjects completed 12 months of follow-up. Regarding the objective success between the I-stop-mini group and the Obtryx group, 1-month postoperative (3.6 ± 5.2 vs 3.9 ± 12.6; p = .765), 6-month postoperative (3.9 ± 5.1 vs 4.2 ± 12.6; p = .848), and 12-month postoperative (4.6 ± 5.6 vs 4.5 ± 13.6; p = .980) 1-hour pad tests showed no significant difference. The 12-month subjective cure rates decreased from 94.7% (1-month postoperative) to 91.2% (12-month postoperative) in the I-stop-mini group and 95.2% (1-month postoperative) to 85.0% (12-month postoperative) in the Obtryx group. Similar and durable efficacy was observed between the 2 groups. The I-stop-mini group had shorter operative times and hospital stays than the Obtryx group; however, both groups showed similar adverse event rates. CONCLUSION: The objective success and subjective cure rates of I-stop-mini did not differ to those of Obtryx. However, long-term data and further prospective studies on I-stop-mini are necessary to arrive at a definite conclusion.


Assuntos
Slings Suburetrais , Incontinência Urinária por Estresse , Feminino , Seguimentos , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Slings Suburetrais/efeitos adversos , Resultado do Tratamento , Incontinência Urinária por Estresse/cirurgia
11.
Artigo em Inglês | MEDLINE | ID: mdl-31614465

RESUMO

Radical hysterectomy (RH) is the standard treatment for early stage cervical cancer, but the surgical approach for locally bulky-size cervical cancer (LBS-CC) is still unclear. We retrospectively compared the outcomes of women with LBS-CC treated with neoadjuvant chemotherapy (NACT) and subsequent RH between the robotic (R-RH) and abdominal approaches (A-RH). Between 2012 and 2014, 39 women with LBS-CC FIGO (International Federation of Gynecology and Obstetrics) stage IB2-IIB were treated with NACT-R-RH (n = 18) or NACT-A-RH (n = 21). Surgical parameters and prognosis were compared. Patient characteristics were not significantly different between the groups, but the NACT-R-RH group had significantly more patients with FIGO stage IIB disease, received multi-agent-based NACT, and had a lower percentage of deep stromal invasion than the NACT-A-RH group. After NACT-R-RH, surgical parameters were better, but survival outcomes, such as disease-free survival (DFS) and overall survival (OS), were significantly worse. On multivariate analysis, FIGO stage IIB contributed to worse DFS (p = 0.003) and worse OS (p = 0.012) in the NACT-A-RH group. Women with LBS-CC treated with NACT-R-RH have better perioperative outcomes but poorer survival outcomes compared with those treated with NACT-A-RH. Thus, patients with FIGO stage IIB LBS-CC disease might not be suitable for surgery after multi-agent-based NACT.


Assuntos
Antineoplásicos/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/cirurgia , Histerectomia/métodos , Terapia Neoadjuvante/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/cirurgia , Adulto , Idoso , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Taiwan , Neoplasias do Colo do Útero/patologia
14.
Biochemistry ; 51(33): 6632-43, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22856882

RESUMO

Crystal structures of the GCN4 bZIP (basic region/leucine zipper) with the AP-1 or CRE site show how each GCN4 basic region binds to a 4 bp cognate half-site as a single DNA target; however, this may not always fully describe how bZIP proteins interact with their target sites. Previously, we showed that the GCN4 basic region interacts with all 5 bp in half-site TTGCG (termed 5H-LR) and that 5H-LR comprises two 4 bp subsites, TTGC and TGCG, which individually are also target sites of the basic region. In this work, we explore how the basic region interacts with 5H-LR when the bZIP dimer localizes to full-sites. Using AMBER molecular modeling, we simulated GCN4 bZIP complexes with full-sites containing 5H-LR to investigate in silico the interface between the basic region and 5H-LR. We also performed in vitro investigation of bZIP-DNA interactions at a number of full-sites that contain 5H-LR versus either subsite: we analyzed results from DNase I footprinting and electrophoretic mobility shift assay (EMSA) and from EMSA titrations to quantify binding affinities. Our computational and experimental results together support a highly dynamic DNA-binding model: when a bZIP dimer localizes to its target full-site, the basic region can alternately recognize either subsite as a distinct target at 5H-LR and translocate between the subsites, potentially by sliding and hopping. This model provides added insights into how α-helical DNA-binding domains of transcription factors can localize to their gene regulatory sequences in vivo.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Sequência de Bases , Fatores de Transcrição de Zíper de Leucina Básica/química , Sítios de Ligação/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Pegada de DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Ligação de Hidrogênio , Proteínas de Saccharomyces cerevisiae/metabolismo
15.
Biochemistry ; 47(36): 9646-52, 2008 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-18702507

RESUMO

We previously reported that the wt bZIP, a hybrid of the GCN4 basic region and C/EBP leucine zipper, not only recognizes GCN4 cognate site AP-1 (TGACTCA) but also selectively targets noncognate DNA sites, in particular the C/EBP site (TTGCGCAA). In this work, we used electrophoretic mobility shift assay and DNase I footprinting to investigate the factors driving the high affinity between the wt bZIP and the C/EBP site. We found that on each strand of the C/EBP site, the wt bZIP recognizes two 4 bp subsites, TTGC and TGCG, which overlap to form the effective 5 bp half-site (TTGCG). The affinity of the wt bZIP for the overall 5 bp half-site is >or=10-fold stronger than that for either 4 bp subsite. Our results suggest that interactions of the wt bZIP with both subsites contribute to the strong affinity at the overall 5 bp half-site and, consequently, the C/EBP site. Accordingly, we propose that the wt bZIP undergoes conformational changes to slide between the two overlapping subsites on the same DNA strand and establish sequence-selective contacts with the different subsites. The proposed binding mechanism expands our understanding of what constitutes an actual DNA target site in protein-DNA interactions.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/química , DNA/química , Zíper de Leucina/fisiologia , Modelos Químicos , Elementos de Resposta/fisiologia , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , DNA/genética , DNA/metabolismo , Pegada de DNA/métodos , Desoxirribonuclease I/química , Humanos , Ligação Proteica/fisiologia
16.
Protein Expr Purif ; 59(2): 314-9, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18406169

RESUMO

In our work with designed minimalist proteins based on the bZIP motif, we have found our His-tagged proteins to be prone to inclusion body formation and aggregation; we suspect this problem is largely due to the His tag, known to promote aggregation. Using AhR6-C/EBP, a hybrid of the AhR basic region and C/EBP leucine zipper, as representative of our bZIP-like protein family, we attempted removal of the His tag with enterokinase (EK) but obtained the desired cleavage product in very small yield. EK is known for proteolysis at noncanonical sites, and most cleavage occurred at unintended sites. We manipulated experimental conditions to improve specificity of proteolysis and analyzed the cleavage products; no effect was observed after changing pH, temperature, or the amount of EK. We then suspected the accessibility of the EK site was impeded due to protein aggregation. We found that the easily implemented strategy of addition of urea (1-4 M) greatly improved EK cleavage specificity at the canonical site and reduced adventitious cleavage. We believe that this enhancement in specificity is due to a more "open" protein structure, in which the now accessible canonical target can compete effectively with adventitious cleavage sites of related sequence.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/isolamento & purificação , Enteropeptidase/química , Receptores de Hidrocarboneto Arílico/isolamento & purificação , Proteínas Recombinantes de Fusão/isolamento & purificação , Sequência de Aminoácidos , Proteínas Estimuladoras de Ligação a CCAAT/química , Proteínas Estimuladoras de Ligação a CCAAT/genética , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Receptores de Hidrocarboneto Arílico/química , Receptores de Hidrocarboneto Arílico/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Temperatura , Ureia/química
17.
Biochemistry ; 46(6): 1663-71, 2007 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-17279629

RESUMO

We previously reported that a basic region/leucine zipper (bZIP) protein, a hybrid of the GCN4 basic region and C/EBP leucine zipper, not only recognizes cognate target sites AP-1 (5'-TGACTCA-3') and cAMP-response element (CRE) (5'-TGACGTCA-3') but also binds selectively to noncognate DNA sites: C/EBP (CCAAT/enhancer binding protein, 5'-TTGCGCAA), XRE1 (xenobiotic response element, 5'-TTGCGTGA), HRE (HIF response element, 5'-GCACGTAG), and E-box (5'-CACGTG). In this work, we used electrophoretic mobility shift assay (EMSA) and circular dichroism (CD) for more extensive characterization of the binding of wt bZIP dimer to noncognate sites as well as full- and half-site derivatives, and we examined changes in flanking sequences. Quantitative EMSA titrations were used to measure dissociation constants of this hybrid, wt bZIP, to DNA duplexes: Full-site binding affinities gradually decrease from cognate sites AP-1 and CRE with Kd values of 13 and 12 nM, respectively, to noncognate sites with Kd values of 120 nM to low microM. DNA-binding selectivity at half sites is maintained; however, half-site binding affinities sharply decrease from the cognate half site (Kd = 84 nM) to noncognate half sites (all Kd values > 2 microM). CD shows that comparable levels of alpha-helical structure are induced in wt bZIP upon binding to cognate AP-1 or noncognate sites. Thus, noncognate sites may contribute to preorganization of stable protein structure before binding target DNA sites. This work demonstrates that the bZIP scaffold may be a powerful tool in the design of small, alpha-helical proteins with desired DNA recognition properties.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/fisiologia , Sítios de Ligação/fisiologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Sequências Reguladoras de Ácido Nucleico/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Fatores de Transcrição de Zíper de Leucina Básica/genética , Proteínas Estimuladoras de Ligação a CCAAT/fisiologia , Dicroísmo Circular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Pegada de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Proteínas Recombinantes de Fusão/metabolismo , Fator de Transcrição AP-1/metabolismo
18.
Biochim Biophys Acta ; 1764(7): 1252-9, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16784907

RESUMO

We show that a minimalist basic region/leucine zipper (bZIP) hybrid, comprising the yeast GCN4 basic region and C/EBP leucine zipper, can target mammalian and other gene regulatory sequences naturally targeted by other bZIP and basic/helix-loop-helix (bHLH) proteins. We previously reported that this hybrid, wt bZIP, is capable of sequence-specific, high-affinity binding of DNA comparable to that of native GCN4 to the cognate AP-1 and CRE DNA sites. In this work, we used DNase I footprinting and electrophoretic mobility shift assay to show that wt bZIP can also specifically target noncognate gene regulatory sequences: C/EBP (CCAAT/enhancer binding protein, 5'-TTGCGCAA), XRE1 (Xenobiotic response element, 5'-TTGCGTGA), HRE (HIF response element, 5'-GCACGTAG), and the E-box (Enhancer box, 5'-CACGTG). Although wt bZIP still targets AP-1 with strongest affinity, both DNA-binding specificity and affinity are maintained with wt bZIP binding to noncognate gene regulatory sequences: the dissociation constant for wt bZIP in complex with AP-1 is 13 nM, while that for C/EBP is 120 nM, XRE1 240 nM, and E-box and HRE are in the microM range. These results demonstrate that the bZIP possesses the versatility to bind various sequences with varying affinities, illustrating the potential to fine-tune a designed protein's affinity for its DNA target. Thus, the bZIP scaffold may be a powerful tool in design of small, alpha-helical proteins with desired DNA recognition properties.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Proteínas de Ligação a DNA/metabolismo , Sequências Reguladoras de Ácido Nucleico/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Translocador Nuclear Receptor Aril Hidrocarboneto/genética , Sequência de Bases , Fatores de Transcrição de Zíper de Leucina Básica/química , Fatores de Transcrição de Zíper de Leucina Básica/genética , Sítios de Ligação/genética , Proteínas Estimuladoras de Ligação a CCAAT/genética , DNA/química , DNA/genética , DNA/metabolismo , Pegada de DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Elementos E-Box/genética , Ensaio de Desvio de Mobilidade Eletroforética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Modelos Moleculares , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Elementos de Resposta/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Fator de Transcrição AP-1/genética , Fatores de Transcrição/química , Fatores de Transcrição/genética
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