RESUMEN

This work presents a heuristic for the selection of a time delay based on optimizing the global maximum of mutual information in orthonormal coordinates for embedding a dynamical system. This criterion is demonstrated to be more robust compared to methods that utilize a local minimum, as the global maximum is guaranteed to exist in the proposed coordinate system for any dynamical system. By contrast, methods using local minima can be ill-posed as a local minimum can be difficult to identify in the presence of noise or may simply not exist. The performance of the global maximum and local minimum methods are compared in the context of causality detection using convergent cross mapping using both a noisy Lorenz system and experimental data from an oscillating plasma source. The proposed heuristic for time lag selection is shown to be more consistent in the presence of noise and closer to an optimal uniform time lag selection.

RESUMEN

BACKGROUND: Germline genetic testing is traditionally carried out in patients suspected with hereditary cancer syndrome for enhanced cancer surveillance and/or preventive strategies, but is increasingly carried out for therapeutic indications. MATERIALS AND METHODS: We conducted a retrospective review of patients who underwent germline genetic testing at our centre to determine the prevalence of actionable pathogenic germline variants (PGV) and their clinical utility. RESULTS: From 2000 to 2022, 1154 cancer patients underwent germline testing, with the majority (945/1154) tested with multi-gene panels. Four hundred and eleven (35.6%) patients harboured a PGV and 334 (81%) were clinically actionable. BRCA1/2 accounted for 62.3% of actionable mutations, followed by mismatch repair (18%), and other homologous recombination repair (HRR) genes (19.7%). One hundred and fifty-two germline-positive patients have advanced cancers, and 79 received germline-directed therapies (poly ADP ribose polymerase inhibitors = 75; immunotherapy = 4). Median duration of immunotherapy and poly ADP ribose polymerase were 20.5 months (range 5-40 months) and 8 months (range 1-76 months), respectively. Among BRCA/HRR mutation carriers who received platinum-based chemotherapy, pathological complete response rate in the neoadjuvant setting was 53% (n = 17 breast cancers) and objective response rate was >80% in the advanced setting (n = 71). CONCLUSIONS: One-third of cancer patients tested carried a PGV and ∼80% were clinically actionable. Three-quarters of germline-positive advanced cancer patients received germline-directed therapies in the real world, underscoring the practical utility of germline testing to guide cancer therapeutics.

Asunto(s)

Predisposición Genética a la Enfermedad , Pruebas Genéticas , Mutación de Línea Germinal , Neoplasias , Humanos , Femenino , Estudios Retrospectivos , Masculino , Pruebas Genéticas/métodos , Adulto , Persona de Mediana Edad , Neoplasias/genética , Anciano , Adulto Joven , Asia/epidemiología , Adolescente , Anciano de 80 o más Años

RESUMEN

INTRODUCTION: Available examinations for women with postmenopausal bleeding include transvaginal sonography to measure endometrial thickness (TVS-ET), and invasive endometrial assessment using hysteroscopy/endometrial biopsy. However, selection of the examination method seldom involves consideration of patient preferences. The aim of this study was to examine patient preferences for the method used to investigate postmenopausal bleeding. METHODS: Women were asked to complete an interviewer-administered structured survey before they underwent clinical investigations at a university gynaecology unit from June 2016 to June 2017. Using the standard gamble approach, women were asked to choose between invasive assessment by hysteroscopy/endometrial biopsy (gold standard) or TVS-ET with a risk of missing endometrial cancer. The risk of missing endometrial cancer during TVS-ET was varied until each woman was indifferent to either option. RESULTS: The median detection rate for endometrial cancer required using TVS-ET was 95% (interquartile range=80%-99.9%). In total, 200 women completed the survey, and 77 (38.5%) women required TVS-ET to have a 99.9% detection rate for endometrial cancer. Prior hysteroscopy experience was the only factor that influenced the women's decisions: a significantly higher detection rate was required by this patient group than by patients without previous hysteroscopy experience (P=0.047). CONCLUSION: A substantial proportion of women would accept TVS-ET alone for the investigation of postmenopausal bleeding. In the era of patientcentred care, clinicians should incorporate patient preferences and enable women to make informed choices concerning the management of postmenopausal bleeding.

Asunto(s)

Neoplasias Endometriales , Histeroscopía , Biopsia , Neoplasias Endometriales/diagnóstico por imagen , Femenino , Humanos , Masculino , Posmenopausia , Embarazo , Sensibilidad y Especificidad , Ultrasonografía , Hemorragia Uterina/diagnóstico por imagen , Hemorragia Uterina/etiología

RESUMEN

PURPOSE: Hernia recurrence is an important complication following inguinal hernia repair. Primary closure of ventral hernia defects laparoscopically has been shown to reduce the risk of recurrence and seroma formation. The results for ventral hernias may potentially be applied to direct inguinal hernias. Our aim was to evaluate the value of primary closure of direct defects during laparoscopic inguinal hernia mesh repair in reducing the incidence of early recurrence. METHODS: A retrospective, single-center cohort study was conducted on cases performed from August 2016 to February 2018. Patients with direct inguinal hernias undergoing elective laparoscopic mesh repair were included. When performed, the direct hernia defect was primarily closed with extracorporeal non-absorbable interrupted sutures followed by standard placement of a lightweight mesh covering myopectineal orifices. Early recurrence was defined as occurring within 1 year of surgery. RESULTS: A total of 75 direct inguinal hernias in 53 patients who underwent surgery and completed at least 1 year of follow-up were analyzed. The mean age of patients was 63 years (range 44-82 years); with majority of patients being male (98.1%). There were no significant differences observed between the two patient populations in terms of demographics, mean operative time and risk factors. In 9 (16.9%) patients, the direct hernias were recurrent hernias and all underwent open mesh repair during the index hernia surgery. The majority of hernia repairs (63 hernias in 45 patients, 85%) were performed via the totally extraperitoneal (TEP) approach. 19 patients (35.8%) with 28 direct inguinal hernias underwent primary closure of the direct defect prior to mesh placement; while, 34 patients (64.2%) with 47 direct hernias did not undergo primary closure. There were 3 direct hernia recurrences (6.4%) at 1 year post-operatively, and all occurred in the non-closure group. In comparison, there were no recurrences in the closure group; however, this difference was not statistically significant (p = 0.289) in our study due to the small sample size. CONCLUSION: Closure of direct inguinal hernia defects during laparoscopic mesh repair has been shown to reduce the incidence of early hernia recurrence in our retrospective study but future randomized controlled trials with large numbers would enable us to draw more robust conclusions and perhaps change the way we perform laparoscopic inguinal hernia repair.

Asunto(s)

Hernia Inguinal/cirugía , Herniorrafia/métodos , Laparoscopía/métodos , Mallas Quirúrgicas/normas , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia , Estudios Retrospectivos , Suturas

RESUMEN

Long bone fractures in racehorses may present as stress fractures which have a good prognosis, or complete fractures, which often result in a fatal outcome. In order to identify differences in modifiable management practices that may contribute to these outcomes, racing histories of horses with humeral or tibial fractures and of matched controls were examined. A retrospective case-control study of Australian Thoroughbred racehorses diagnosed with a fracture of the humerus or tibia by scintigraphy or at post-mortem between 2002 and 2016 was undertaken. Control horses were matched from the same race or trial on age and sex. Statistical analysis was performed using conditional logistic regression, χ2 and Mann-Whitney U tests. More humeral fractures than tibial fractures were fatal (12/47, 26% vs. 3/35, 8.6%, P = 0.049). No differences in pre-injury racing histories were observed between cases and controls for humeral and tibial fractures. Both humeral and tibial fracture case horses were younger than the registered Thoroughbred racing population (P < 0.001), but horses sustaining humeral fractures were older than those with tibial fractures (3.3 ± 0.9 vs. 2.8 ± 0.8 years, P = 0.005) yet raced fewer times prior to the injury (0.5 ± 1.1 vs. 1.3 ± 1.7 races, P = 0.009). Horses with fatal humeral fractures were less likely to have raced than those with non-fatal humeral fractures (16.7% vs. 55.6%, P = 0.02). In conclusion, tibial and humeral fractures occur in young racehorses, and humeral fractures are more likely to be fatal in those with the least exposure to trialling and racing.

Asunto(s)

Caballos/lesiones , Fracturas del Húmero/veterinaria , Deportes , Fracturas de la Tibia/veterinaria , Factores de Edad , Animales , Australia , Estudios de Casos y Controles , Femenino , Fracturas del Húmero/etiología , Fracturas del Húmero/mortalidad , Masculino , Condicionamiento Físico Animal , Cintigrafía/veterinaria , Estudios Retrospectivos , Factores de Riesgo , Fracturas de la Tibia/etiología , Fracturas de la Tibia/mortalidad

RESUMEN

Recent studies have indicated that the nanoindentation measured stiffness of carcinoma adherent cells is in general lower than normal cells, thus suggesting that cell stiffness may serve as a bio-marker for carcinoma. However, the proper establishment of such a conclusion would require biophysical understanding of the underlying mechanism of the cell stiffness. In this work, we compared the elastic moduli of the actin cytoskeletons of Hey A8 ovarian carcinoma cells with and without metastasis (HM and NM), as measured by 2D atomic force microscopy (AFM) with low-depth nanoindentation via a rate-jump method. The results indicate clearly that HM cells showed lower actin cytoskeleton stiffness atop of their nucleus position and higher actin cytoskeleton stiffness at their rims, compared to NM cells, suggesting that the local stiffness on the cytoskeleton can reflect actin filament distribution. Immunofluorescence staining and scanning electron microscopy (SEM) also indicated that the difference in stiffness in Hey A8 cells with different metastasis is associated with their F-actin rearrangement. Finite-element modelling (FEM) shows that a migrating cell would have its actin filaments bundled together to form stress fibers, which would exhibit lower indentation stiffness than the less aligned arrangement of filaments in a non-migrating cell. The results here indicate that the actin cytoskeleton stiffness can serve as a reliable marker for grading the metastasis of adherent carcinoma cells due to their cytoskeleton change and potentially predicting the migration direction of the cells.

Asunto(s)

Citoesqueleto de Actina/fisiología , Neoplasias Ováricas/patología , Neoplasias Ováricas/fisiopatología , Línea Celular Tumoral , Movimiento Celular , Núcleo Celular , Módulo de Elasticidad , Femenino , Humanos , Microscopía de Fuerza Atómica

RESUMEN

Ovarian cancer is a nearly uniform lethal disease and its highly aggressive metastatic phenotype portends a poor prognosis. Lack of a well-controlled, relevant experimental model has been a major obstacle to identifying key molecules causing metastasis. Here we describe the creation of a new isogenic model of spontaneous human ovarian cancer metastasis exhibiting opposite phenotypes-highly metastatic (HM) and non-metastatic (NM)-both in vitro and in vivo. HM was unique in its ability to metastasize consistently to the peritoneum, mimicking the major dissemination route of human ovarian cancer. In contrast, NM failed to form detectable metastases, although it was equally tumorigenic. Using comparative label-free quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS), we identified ß-catenin, which we demonstrated for the first time as having a direct role in the pathogenesis of ovarian cancer metastasis. Our studies also revealed a previously unrecognized role of ß-catenin in the downregulation of multiple microRNAs (miRNAs) through attenuating miRNA biogenesis by targeting Dicer, a key component of the miRNA-processing machinery. One such downregulated miRNAs was miR-29s involved in epithelial-to-mesenchymal transition and subsequent stem cell traits. Silencing ß-catenin or overexpressing Dicer or miR-29 mimics in HM significantly reduced the ability of these cells to migrate. ß-catenin-knockdown cells also failed to metastasize in an orthotopic model of ovarian cancer. Meta-analysis revealed an increase in CTNNB1 and a decrease in DICER1 expression levels in the high-risk group. These results uncover ß-catenin as a critical factor in promoting ovarian cancer aggressiveness and a new mechanism linking between ß-catenin and miRNA downregulation underlying this process.

Asunto(s)

Carcinogénesis/genética , ARN Helicasas DEAD-box/genética , MicroARNs/genética , Neoplasias Ováricas/genética , Ribonucleasa III/genética , beta Catenina/genética , Animales , Línea Celular Tumoral , Proliferación Celular/genética , Cromatografía Liquida , Transición Epitelial-Mesenquimal , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Metástasis de la Neoplasia , Neoplasias Ováricas/patología , Espectrometría de Masas en Tándem , Vía de Señalización Wnt , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Suspended cells are difficult to be transfected by common biochemical methods which require cell attachment to a substrate. Mechanical oscillations of suspended cells at certain frequencies are found to result in significant increase in membrane permeability and potency for delivery of nano-particles and genetic materials into the cells. Nanomaterials including siRNAs are found to penetrate into suspended cells after subjecting to short-time mechanical oscillations, which would otherwise not affect the viability of the cells. Theoretical analysis indicates significant deformation of the actin-filament network in the cytoskeleton cortex during mechanical oscillations at the experimental frequency, which is likely to rupture the soft phospholipid bilayer leading to increased membrane permeability. The results here indicate a new method for enhancing cell transfection.

Asunto(s)

Estrés Mecánico , Transfección/métodos , Transformación Genética , Línea Celular Tumoral , Membrana Celular/fisiología , Endocitosis , Genes , Humanos , Nanoestructuras , Permeabilidad

RESUMEN

OBJECTIVE: To identify predictive factors for residual disease in hysterectomy specimens after a loop electrical excision procedure (LEEP) or cold knife conization in early-stage cervical cancer. STUDY DESIGN: A retrospective review was undertaken of the clinical records and pathology reports of 108 consecutive patients who were diagnosed with early invasive cervical cancer stage IA1 to IB1 by cold knife conization or LEEP, and underwent subsequent hysterectomy or radical hysterectomy at the Gynae-oncology Unit, Queen Elizabeth Hospital between 2000 and 2012. Residual disease was defined as the presence of cervical intra-epithelial neoplasia (CIN) 2-3 or invasive carcinoma in hysterectomy specimens. Clinicopathological factors associated with residual disease were analyzed. Risk factors for the prediction of residual disease were identified by univariate and multivariate analysis. RESULTS: Residual disease was found in 32 (29.7%) patients. Stage, tumour size, depth of invasion, lymphovascular space invasion, ectocervical margin, endocervical margin, and combined ectocervical and endocervical margin were significantly associated with residual disease in hysterectomy specimens on univariate analysis. On multivariate analysis, depth of invasion (odds ratio 2.1, p=0.033) and combined margin status (odds ratio 10.8, p≤0.001) were independent risk factors for residual disease. In a subgroup analysis using depth of invasion ≤5mm and a negative combined margin, none (0%) of the 52 patients who met the criteria had residual disease. CONCLUSIONS: Conization (combined ectocervical and endocervical) margin and tumour depth of invasion are independent predictors of residual disease in hysterectomy specimens. A negative conization margin and depth of invasion ≤5mm are associated with low risk of residual disease in patients with early-stage cervical cancer.

Asunto(s)

Cuello del Útero/patología , Conización , Histerectomía , Neoplasia Residual/patología , Displasia del Cuello del Útero/patología , Neoplasias del Cuello Uterino/patología , Adulto , Anciano , Anciano de 80 o más Años , Cuello del Útero/cirugía , Electrocirugia , Femenino , Humanos , Persona de Mediana Edad , Neoplasia Residual/cirugía , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Neoplasias del Cuello Uterino/cirugía , Displasia del Cuello del Útero/cirugía

RESUMEN

OBJECTIVE: To estimate the accuracy of transvaginal ultrasound (TVS) measurement of endometrial thickness (ET) in diagnosing endometrial cancer in postmenopausal women with vaginal bleeding (PMB). DESIGN: Retrospective cohort study. SETTING: One-stop PMB clinic in a Hong Kong teaching hospital. POPULATION: A cohort of 4383 women with PMB. METHODS: Transvaginal ultrasonic measurement of ET and endometrial biopsies were obtained in women presenting with PMB between 2002 and 2013. Endometrial histology was used as the reference standard to calculate accuracy estimates. MAIN OUTCOME MEASURES: Accuracy data for TVS ET presented as sensitivity, specificity, and area under the receiver operator characteristic (ROC) curve. RESULTS: Endometrial cancer was diagnosed in 3.8% of women. The median ET in those with endometrial cancer was significantly higher than those with benign conditions (15.7 versus 3.2 mm, P < 0.001). The area under the ROC curve was 0.92 (95% CI 0.89-0.94). The sensitivity for the detection of endometrial cancer at 3-, 4-, and 5-mm cut-offs were 97.0% (95% CI 94.5-99.6%), 94.1% (95% CI 90.5-97.6%), and 93.5% (95% CI 89.7-97.2%), respectively. The corresponding estimates of specificity at these thresholds were 45.3% (95% CI 43.8-46.8%), 66.8% (65.4-68.2%), and 74.0% (72.7-75.4%). CONCLUSIONS: Transvaginal ultrasound using a 3-mm cut-off has high sensitivity for detecting endometrial cancer and can identify women with PMB who are highly unlikely to have endometrial cancer, thereby avoiding more invasive endometrial biopsy.

Asunto(s)

Neoplasias Endometriales/complicaciones , Neoplasias Endometriales/patología , Endometrio/patología , Posmenopausia , Hemorragia Uterina/etiología , Biopsia , Estudios de Cohortes , Neoplasias Endometriales/diagnóstico por imagen , Endometrio/diagnóstico por imagen , Femenino , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Ultrasonografía

RESUMEN

BACKGROUND: ß-Catenin is a potent oncogenic protein in colorectal cancer (CRC), but the targets and regulation of this important signalling molecule are not completely understood. Hypoxia is a prominent feature of solid tumours that contributes to cancer progression. METHODS: Here, we analysed the regulation between Nur77 and ß-catenin under hypoxic conditions. Cell proliferation, migration, and invasion assays were performed to assess functional consequences. RESULTS: We showed that hypoxia stimulated co-upregulation of ß-catenin and Nur77 in a number of human CRC cell lines. Interestingly, expression of ß-catenin and Nur77 by hypoxia formed a mutual feedback regulation circuits that conferred aggressive growth of CRC. Overexpression of ß-catenin increased Nur77 transcription through hypoxia-inducible factor-1α rather than T-cell factor. Nur77-mediated activation of ß-catenin by hypoxia was independent of both DNA binding and transactivation. Further, we showed that hypoxic activation of ß-catenin was independent of the classical adenomatous polyposis coli and p53 pathways, but stimulated by phosphatidylinositol 3-kinase/Akt in a Nur77-dependent manner. Under hypoxic conditions, enhanced ß-catenin and Nur77 expression synergistically stimulated CRC cell migration, invasion, and epithelial-mesenchymal transition. CONCLUSION: These findings provide a novel molecular mechanism for hypoxic CRCs that may contribute to tumour progression, and its targeting may represent an effective therapeutic avenue.

Asunto(s)

Neoplasias del Colon/patología , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , beta Catenina/metabolismo , Poliposis Adenomatosa del Colon/metabolismo , Hipoxia de la Célula/fisiología , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Proteínas de Unión al ADN/metabolismo , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Células HEK293 , Células HT29 , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Invasividad Neoplásica , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Fosfatidilinositol 3-Quinasa/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Interferencia de ARN , ARN Interferente Pequeño , Transducción de Señal , Activación Transcripcional , Proteína p53 Supresora de Tumor/metabolismo , Regulación hacia Arriba , beta Catenina/genética

RESUMEN

Cisplatin and paclitaxel are standard chemotherapy for metastatic ovarian cancer, but with limited efficacy. Cancer stem/progenitor cells (or tumor-initiating cells, TICs) are hypothesized to be chemoresistant, and the existence of TICs in ovarian cancer has been previously demonstrated. However, the key signals and molecular events regulating the formation and expansion of ovarian tumor-initiating cells (OTICs) remain elusive. Here, we show that c-Kit is not just a marker of OTICs, but also a critical mediator of the phenotype that can be a viable target for the treatment of ovarian cancer. In contrast to non-OICs, c-Kit was overexpressed in OTICs. Moreover, the use of small interfering RNA to inhibit c-Kit expression markedly attenuated the number and size of OTIC subpopulations, inhibited the expression of stem cell markers and decreased the tumorigenic capabilities of OTICs. Imatinib (Gleevec), a clinical drug that blocks c-Kit kinase activity, also demonstrated its inhibition potency on OTICs. In addition, cisplatin/paclitaxel, which killed non-OTICs, with c-Kit knockdown or imatinib revealed that this was critically required for intervening ovarian cancer progression and recurrence in vitro and in xenograft tumors in vivo. Similar results were obtained with OTICs derived from ovarian carcinoma patients. Studies into the mechanisms suggest an important role for the activation of Wnt/ß-catenin and ATP-binding cassette G2 downstream of c-Kit. The tumor-promoting microenvironment, such as hypoxia, could promote OTICs via upregulation of c-Kit expression. These results unravel an integral role for c-Kit in ovarian neoplastic processes and shed light on its mechanisms of action.

Asunto(s)

Benzamidas/farmacología , Resistencia a Antineoplásicos/genética , Neoplasias Ováricas , Piperazinas/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-kit/metabolismo , Pirimidinas/farmacología , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Antineoplásicos/farmacología , Hipoxia de la Célula , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Cisplatino/farmacología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Mesilato de Imatinib , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteínas de Neoplasias/metabolismo , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Paclitaxel/farmacología , Proteínas Proto-Oncogénicas c-kit/genética , Interferencia de ARN , ARN Interferente Pequeño , Microambiente Tumoral , Proteínas Wnt/metabolismo , Vía de Señalización Wnt/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , beta Catenina/metabolismo

RESUMEN

The PFTK1 gene encodes a cdc2-related serine/threonine protein kinase that has been shown to confer cell migratory properties in hepatocellular carcinoma (HCC). However, the prognostic value and biological mechanism by which PFTK1 promotes HCC motility remain largely unknown. Here, we showed from tissue microarray that common upregulations of PFTK1 in primary HCC tumors (n=133/180) correlated significantly with early age onset (40 years), advance tumor grading and presence of microvascular invasion (P0.05). To understand downstream phosphorylated substrate(s) of PFTK1, phospho-proteins in PFTK1 expressing and knockdown Hep3B cells were profiled by two-dimensional-polyacrylamide gel electrophoresis mass spectrometric analysis. Protein identification of differential spots revealed ß-actin (ACTB) and transgelin2 (TAGLN2) as the two most profound phosphorylated changes affected by PFTK1. We verified the presence of TAGLN2 serine phosphorylation and ACTB tyrosine phosphorylation. Moreover, reduced TAGLN2 and ACTB phosphorylations in PFTK1-suppressed Hep3B corresponded to distinct actin depolymerizations and marked inhibition on cell invasion and motility. Given that TAGLN2 is a tumor suppressor whose function has been ascribed in cancer metastasis, we examined if TAGLN2 is an intermediate substrate in the biological path of PFTK1. We showed in PFTK1-suppressed cells that knockdown of TAGLN2 over-rode the inhibitory effect on cell invasion and motility, and a recovery on actin polymerization was evident. Interestingly, we also found that unphosphorylated TAGLN2 in PFTK1-suppressed cells elicited strong actin-binding ability, a mechanism that possibly halts the actin cytoskeleton dynamics. Site-directed mutagenesis of TAGLN2 suggested that PFTK1 regulates the actin-binding affinity of TAGLN2 through the S83 and S163 residues, which if mutated can significantly affect HCC cell motility. Taken together, our data propose a novel, oncogene-tumor suppressor interplay, where oncogenic PFTK1 confers HCC cell motility through inactivating the actin-binding motile suppressing function of TAGLN2 via phosphorylation.

Asunto(s)

Carcinoma Hepatocelular/genética , Movimiento Celular/genética , Quinasas Ciclina-Dependientes/metabolismo , Neoplasias Hepáticas/genética , Proteínas de Microfilamentos/metabolismo , Proteínas Musculares/metabolismo , Actinas/metabolismo , Adulto , Biomarcadores de Tumor , Línea Celular Tumoral , Femenino , Genes Supresores de Tumor , Humanos , Masculino , Fosforilación , Pronóstico

RESUMEN

Gonadotropin-releasing hormone (GnRH) is a potent prometastatic factor in ovarian cancer, but the intracellular signaling events are not well understood. The classical Gα(q)-phospholipase C signal transduction pathway known to operate in the pituitary is not involved in GnRH actions at non-pituitary targets. Here we showed that GnRH treatment of ovarian cancer cells led to a rapid and remarkable tyrosine phosphorylation of p120 catenin (p120(ctn)), which was mediated by P-cadherin. The use of P-cadherin small interfering RNA or neutralizing antibodies to inhibit P-cadherin expression and function resulted in diminished p120(ctn) activation, confirming that the effect was P-cadherin specific. On exploring how P-cadherin, which lacks intrinsic kinase activity, might regulate the activation of p120(ctn), we found that P-cadherin could induce the ligand-independent activation of insulin-like growth factor-1 receptor (IGF-1R). Inhibition of IGF-1R expression or its activity significantly inhibited GnRH-induced p120(ctn) activation, and the subsequent cell migration and invasion. In addition, we showed that IGF-1R regulation by P-cadherin was associated with complex formation between IGF-1R and P-cadherin, and this regulation was also observed to be in vivo correlated with metastasis. Furthermore, using a mouse model of ovarian cancer metastasis, GnRH receptor knockdown was shown to diminish peritoneal dissemination of tumors and ascites formation. These findings suggest for the first time that GnRH can initiate an outside-in p120(ctn) signal transduction through the cross-talk between P-cadherin and IGF-1R, thus providing a novel molecular mechanism by which GnRH may control the high level of aggressiveness and invasion and metastasis potential that are characteristic of ovarian cancer.

Asunto(s)

Cadherinas/fisiología , Carcinoma/patología , Cateninas/fisiología , Hormona Liberadora de Gonadotropina/farmacología , Neoplasias Ováricas/patología , Receptor IGF Tipo 1/fisiología , Animales , Cadherinas/antagonistas & inhibidores , Cadherinas/genética , Carcinoma/genética , Cateninas/genética , Cateninas/metabolismo , Células Cultivadas , Sinergismo Farmacológico , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Hormona Liberadora de Gonadotropina/efectos adversos , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Metástasis de la Neoplasia , Neoplasias Ováricas/genética , Receptor IGF Tipo 1/antagonistas & inhibidores , Receptor IGF Tipo 1/genética , Receptores LHRH/antagonistas & inhibidores , Receptores LHRH/genética , Receptores LHRH/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Catenina delta

RESUMEN

Ovarian cancer is highly metastatic with a poor prognosis. The serine/threonine kinase, p70 S6 kinase (p70(S6K)), which is a downstream effector of phosphatidylinositol 3-kinase/Akt pathway, is frequently activated in ovarian cancer. Here, we show that p70(S6K) is a critical regulator of the actin cytoskeleton in the acquisition of the metastatic phenotype. This regulation is through two important activities: p70(S6K) acts as an actin filament cross-linking protein and as a Rho family GTPase-activating protein. Ectopic expression of constitutively active p70(S6K) in ovarian cancer cells induced a marked reorganization of the actin cytoskeleton and promoted directional cell migration. Using cosedimentation and differential sedimentation assays, p70(S6K) was found to directly bind to and cross-link actin filaments. Immunofluorescence studies showed p70(S6K) colocalized with cytochalasin D-sensitive actin at the leading edge of motile cells. The p70(S6K) did not affect the kinetics of spontaneous actin polymerization, but could stabilize actin filaments by the inhibition of cofilin-induced actin depolymerization. In addition, we showed that p70(S6K) stimulated the rapid activation of both Rac1 and Cdc42, and their downstream effector p21-activated kinase (PAK1), but not RhoA. Depletion of p70(S6K) expression or inhibition of its activity resulted in significant inhibition of actin cytoskeleton reorganization and reduced migration, with a concomitant reduction in Rac1, Cdc42 and PAK1 activation, confirming that the effect was p70(S6K) specific. Similarly, the actin cytoskeleton reorganization/migratory phenotype could be reversed by expression of dominant negative Rac1 and Cdc42, or inhibition of PAK1. These results reveal a new direction for understanding the oncogenic roles of p70(S6K) in tumor progression.

Asunto(s)

Actinas/metabolismo , Movimiento Celular , Citoesqueleto/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Actinas/ultraestructura , Western Blotting , Línea Celular Tumoral , Citoesqueleto/ultraestructura , Activación Enzimática/efectos de los fármacos , Femenino , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células Hep G2 , Factor de Crecimiento de Hepatocito/farmacología , Humanos , Microscopía Electrónica , Microscopía Fluorescente , Unión Proteica , Interferencia de ARN , Proteínas Quinasas S6 Ribosómicas 70-kDa/genética , Transfección , Células Tumorales Cultivadas , Proteína de Unión al GTP cdc42/genética , Proteína de Unión al GTP cdc42/metabolismo , Quinasas p21 Activadas/genética , Quinasas p21 Activadas/metabolismo , Proteína de Unión al GTP rac1/genética , Proteína de Unión al GTP rac1/metabolismo

RESUMEN

A maskless method of employing polymer growth inhibitor layers is used to modulate the conflicting parameters of density and alignment of multi-junction nanowires via large-scale low temperature chemical route. This low temperature chemical route is shown to synthesize multi-junction nanostructures without compromising the crystal quality at the interfaces. The final morphology of optimized multi-junctions nanowire arrays can be demonstrated on various substrates due to substrate independence and low temperature processing. Here, we also fabricated devices based on density modulated multi-junction nanowires tuned to infiltrate nanoparticles. The fabrication of hierarchically structured nanowire/nanoparticles composites presents an advantageous structure, one that allows nanoparticles to provide large surface areas for dye adsorption, whilst the nanowires can enhance the light harvesting, electron transport rate, and also the mechanical properties of the films. This work can be of great scientific and commercial interest since the technique employed is of low temperature (<90 degrees C) and economical for large-scale solution processing, much valued in today's flexible display and photovoltaic industries.

RESUMEN

Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and lamellar) can be controlled via the concentration of copolymer, resulting in two different types of micellar packing. The calcination temperature is also controlled to ensure a well-crystalline and stable porous framework. Finally, the synthesized mesoporous TiO(2) film is modified by adding P25 nanoparticles, which act as scattering centers and function as active binders to prevent formation of microcracks. Adding P25 nanoparticles into mesoporous structure helps to provide strong light-harvesting capability and large surface area for high -efficiency dye-sensitized solar cells (DSSC). The short-circuit photocurrent density (J(sc)) of the cell made from mixture of mesoporous TiO(2) and P25 nanoparticles displays a higher efficiency of approximately 6.5% compared to the other homogeneous films. A combination of factors such as increased surface area, introduction of light-scattering particles, and high crystallinity of the mesoporous films leads to enhanced cell performance.

Asunto(s)

Membranas Artificiales , Nanopartículas , Energía Solar , Titanio , Porosidad

RESUMEN

Gonadotropin-releasing hormone (GnRH) receptor expression is often elevated in ovarian cancer, but its potential role in ovarian cancer metastasis has just begun to be revealed. Cadherin switching is a crucial step during tumorigenesis, particularly in metastasis. Here, we showed that GnRH is an inducer of E- to P-cadherin switching, which is reminiscent of that seen during ovarian tumor progression. Overexpression of P-cadherin significantly enhanced, whereas knockdown of P-cadherin reduced migration and invasion regardless of E-cadherin expression, suggesting that inappropriate expression of P-cadherin contributes to the invasive phenotype. These effects of P-cadherin were mediated by activation of the Rho GTPases, Rac1, and Cdc42, through accumulation of p120 catenin (p120(ctn)) in the cytoplasm. The use of p120(ctn) small interfering RNA or chimeric cadherin construct to inhibit p120(ctn) expression and cytoplasmic localization, respectively, resulted in significant inhibition of cell migration and invasion, with a concomitant reduction in Rac1 and Cdc42 activation, confirming that the effect was p120(ctn) specific. Similarly, the migratory/invasive phenotype could be reversed by expression of dominant-negative Rac1 and Cdc42. These results identify for the first time cadherin switching and p120(ctn) signaling as important targets of GnRH function and as novel mediators of invasiveness and tumor progression in ovarian cancer.

Asunto(s)

Cadherinas/fisiología , Cateninas/fisiología , Hormona Liberadora de Gonadotropina/fisiología , Neoplasias Ováricas/patología , Transducción de Señal/fisiología , Proteína de Unión al GTP rac1/fisiología , Línea Celular Tumoral , Movimiento Celular , Femenino , Humanos , Invasividad Neoplásica , Proteína de Unión al GTP cdc42/fisiología , Catenina delta

RESUMEN

2-Methoxyestradiol (2ME2) is a normal physiological metabolite of 17beta-estradiol with anti-proliferative and anti-angiogenic activities. The purpose of this study is to elucidate the mechanism whereby 2ME2 induces endoreduplication of the well-differentiated nasopharyngeal carcinoma (NPC) cells. We report here that 2ME2 induces G2/M phase cell cycle arrest followed by endoreduplication of the well-differentiated HK-1 cells. The increase in chromosome number was confirmed by cytogenetic study. Analysis of stress signaling pathways revealed the phosphorylation activation of ERK, JNK and p38 MAPKs at various times after 2ME2 treatment. Pre-treatment of 2ME2-treated HK-1 cells with JNK inhibitor (SP600125), ERK inhibitor (PD98059) and p38 MAPK inhibitor (SB203580) resulted in the reduction of endoreduplicating cells. Furthermore, the increase in the phosphorylation of JNK was accompanied by an increase in the reactive oxygen species. In addition, endoreduplication was observed in cells after treatment with superoxide donor, 2,3-dimethoxy-1,4-naphoquinone (DMNQ). Confocal microscopic analysis also revealed the increase in mitochondrial superoxide anion in 2ME2-treated HK-1 cells. Pre-treatment of HK-1 cells with superoxide dismutase mimetic 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or overexpressing the mitochondrial enzyme MnSOD resulted in the reduction of phosphorylation of JNK and the formation of endoreduplicating cells. Furthermore, the tubulin filaments in cytoplasm remain intact in 2ME2-treated HK-1 cells after pre-treatment of TEMPO. Our results suggest that 2ME2 induces endoreduplication through the induction of oxidative stress and the activation of MAPK signal pathways. The biological significance of drug-induced endoreduplication will also be discussed.

Asunto(s)

Estradiol/análogos & derivados , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Moduladores de Tubulina/farmacología , 2-Metoxiestradiol , Línea Celular , Proliferación Celular , Relación Dosis-Respuesta a Droga , Activación Enzimática , Estradiol/farmacología , Humanos , Mitocondrias/metabolismo