Colecistitis aguda asociada con COVID-19 grave en el embarazo. Reporte de caso y revisión de la bibliografía / Acute cholecystitis associated with severe COVID-19 in pregnancy. Case report and bibliographic review

Resumen ANTECEDENTES: Las mujeres embarazadas e infectadas con SARS-CoV-2 tuvieron 2.9 veces más probabilidad de requerir ventilación invasiva. La colecistitis aguda es la segunda indicación quirúrgica más común en el embarazo. En la búsqueda bibliográfica no se encontraron reportes de concomitancia de ambas enfermedades durante el embarazo, por este motivo se publica el reporte de caso clínico y se revisa la bibliografía. CASO CLÍNICO: Paciente de 32 años, en curso de las 23 semanas de embarazo. Debido a síntomas de COVID-19, con prueba PCR positiva, se hospitalizó para inicio de ventilación mecánica invasiva. Al noveno día de internamiento tuvo elevación de transaminasas y reporte de TAC de colecistitis aguda alitiásica. Se le indicó la colecistostomía percutánea, con la que se alivió el cuadro hepatobiliar. En el segundo tiempo quirúrgico se procedió a la cesárea. Tres días después experimentó mejoría ventilatoria y bioquímica gradual. A los 32 días de hospitalización se logró la intubación y, después de 54 días, se dio de alta del hospital, sin requerimiento de oxígeno suplementario. CONCLUSIONES: Encontrar, en conjunto con el síndrome de insuficiencia respiratoria aguda por COVID-19 grave que requiere ventilación mecánica invasiva, embarazo previable y colecistitis alitiásica pone en grave peligro a la embarazada y al equipo médico en múltiples dilemas médicos, quirúrgicos y bioéticos. La colecistostomía percutánea en pacientes con inestabilidad hemodinámica y la finalización del embarazo en caso de deterioro ventilatorio ante síndrome de insuficiencia respiratoria aguda es una opción controvertida. Lo conducente, sin duda, son los procedimientos basados en evidencia y las sesiones multidisciplinarias, incluyendo a la familia.

Abstract BACKGROUND: Pregnant women infected with SARS-CoV-2 were 2.9 times more likely to require invasive ventilation. Acute cholecystitis is the second most common surgical indication in pregnancy. In the literature search, no reports of concomitance of both diseases during pregnancy were found, for this reason the clinical case report is published and the literature is reviewed. CASE REPORT: 32-year-old female patient, in the course of 23 weeks of pregnancy. Due to symptoms of COVID-19, with positive PCR test, she was hospitalized for initiation of invasive mechanical ventilation. On the ninth day of hospitalization, she had elevated transaminases and CT report of acute cholecystitis alliasis. Percutaneous cholecystostomy was indicated, which relieved the hepatobiliary symptoms. In the second surgical stage, a cesarean section was performed. Three days later she experienced gradual ventilatory and biochemical improvement. After 32 days of hospitalization, intubation was achieved and, after 54 days, she was discharged from the hospital, without requiring supplemental oxygen. CONCLUSIONS: Finding, in conjunction with severe COVID-19 acute respiratory failure syndrome requiring invasive mechanical ventilation, pre-viable pregnancy, alliasic cholecystitis, places the pregnant woman and the medical team in serious medical, surgical, and bioethical dilemmas. Percutaneous cholecystostomy in patients with hemodynamic instability and termination of pregnancy in case of ventilatory deterioration in the face of acute respiratory failure syndrome is a controversial option. Evidence-based procedures and multidisciplinary sessions, including the family, are undoubtedly conducive.

A Competency-Guided Approach to Optimizing a Physician-Scientist Curriculum.

Physician-scientists are uniquely positioned to achieve significant biomedical advances to improve the human condition. Their clinical and scientific training allows them to bridge fields and contribute to cutting-edge, clinically relevant research. The need for a highly skilled physician-scientist workforce has never been more acute. We propose a competency-guided program design (CGPD) framework that focuses on core skills to enhance the physician-scientist training curriculum. In partnership with clinical and graduate curricula, the CGPD framework can be employed as a tool to meaningfully integrate physician-scientist training, address barriers to attract and sustain the physician-scientist workforce, and avoid overprogramming that detracts from a solid foundation of clinical and graduate research training.

Precision Cancer Medicine: Dynamic Learning of Cancer Biology in a Clinically Meaningful Context.

PURPOSE: Precision medicine is revolutionizing healthcare practices, most notably in oncology. With cancer being the second leading cause of death in the USA, it is important to integrate precision oncology content in undergraduate medical education. METHODS: In 2015, we launched a Clinical Cancer Medicine Integrated Science Course (ISC) for post-clerkship medical students at Vanderbilt University School of Medicine (VUSM). In this ISC, students learned cancer biology and clinical oncology concepts through a combination of classroom and patient care activities. Student feedback from mid- and end-of-course surveys and student match data were analyzed and used to develop ongoing course improvements. RESULTS: To date, 72 medical students have taken the Clinical Cancer Medicine ISC. Over 90% of students who completed end-of-course surveys agreed or strongly agreed that this course advanced their foundational science knowledge in clinical cancer medicine, that clinical relevance was provided during non-clinical foundational science learning activities, and that foundational science learning was embedded in course clinical experiences. Students who took this course most commonly matched in Internal Medicine, Pathology, Pediatrics, and Radiation Oncology. VUSM students who matched into Pathology and Radiation Oncology were more likely to take this ISC than students who matched in other specialties. CONCLUSION: The Clinical Cancer Medicine ISC serves as a model for incorporating precision oncology, cancer biology foundational science, and oncology patient care activities in undergraduate medical education. The course prepares students to care for oncology patients in their fields of interests during their future career in medicine.

Epidemiology, Outcomes, and Associated Factors of Coronavirus Disease 2019 (COVID-19) Reverse Transcriptase Polymerase Chain Reaction-Confirmed Cases in the San Pedro Sula Metropolitan Area, Honduras.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused substantial morbidity and mortality worldwide. Few reports exist in Latin America, a current epicenter of transmission. Here, we aim to describe the epidemiology and outcomes associated with coronavirus disease 2019 (COVID-19) in Honduras. METHODS: Baseline clinical and epidemiological information of SARS-CoV-2 reverse transcriptase polymerase chain reaction-confirmed cases detected between 17 March-4 May in the San Pedro Sula Metropolitan area was collected; for hospitalized cases, clinical data were abstracted. Logistic regression models were fit to determine the factors associated with hospitalization. RESULTS: We identified 877 COVID-19 cases, of which 25% (n = 220) were hospitalized. The 19-44-year age group (57.8%) and males (61.3%) were predominant in overall COVID-19 cases. Of the cases, 34% (n = 299) had at least 1 preexisting medical condition. Individuals aged 45-69 years (adjusted odds ratio [aOR] = 4.05; 95% confidence interval [CI], 2.85-5.76) or ≥70 years (aOR = 9.12; 95% CI, 5.24-15.86), of male sex (aOR = 1.72; 95% CI, 1.21-2.44), and those with a preexisting condition (aOR = 2.12; 95% CI, 1.43-3.14) had higher odds of hospitalization. Of inpatients, 50% were hospitalized more than 7 days. The median length of hospitalization was 13 days (interquartile range [IQR], 8-29) among individuals aged 19-44 years, and 17 days (IQR, 11-24.6) among those aged 45-69. Of the fatal cases, 42% occurred among adults under 60 years old. CONCLUSIONS: Our findings show that a high proportion of COVID-19 cases in Honduras occurred among younger adults, who also constituted a significant proportion of severe and fatal cases. Preexisting conditions were associated with severe outcomes independently from age and were highly prevalent in Honduran COVID-19 cases.

Evaluation of T cells in blood after a short gluten challenge for coeliac disease diagnosis.

BACKGROUND AND AIM: To diagnose coeliac disease (CD) in individuals on a gluten free diet (GFD), we aimed to assess the utility of detecting activated γδ and CD8 T cells expressing gut-homing receptors after a short gluten challenge. METHODS: We studied 15 CD patients and 35 non-CD controls, all exposed to three days of gluten when following a GFD. Peripheral blood was collected before and six days after starting gluten consumption, and the expression of CD103, ß7 and CD38 in γδ and CD8 T cells was assessed by flow cytometry. Determination of IFN-γ and IP-10 was performed by means of ELISPOT and/or Luminex technology. RESULTS: We observed both γδ and CD8 T cells coexpressing CD103, ß7hi and CD38 in every patient with CD on day six, but only in one control. The studied CD8 T subpopulation was easier to detect than the γδ subpopulation. Increased IFN-γ and IP-10 levels after challenge were observed in patients with CD, but not in controls. CONCLUSION: A short three-day gluten challenge elicits the activation of CD103+ ß7hi CD8+ T cells in CD. These cells can be detected by flow cytometry in peripheral blood, opening new possibilities for CD diagnosis in individuals on a GFD.

Integrating Foundational Sciences in a Clinical Context in the Post-Clerkship Curriculum.

PURPOSE: To design, implement, and launch courses that integrate foundational science learning and clinical application in a post-clerkship undergraduate medical school curriculum. METHOD: In Academic Year (AY) 15-16, as part of a comprehensive curricular revision, Vanderbilt University School of Medicine (VUSM) formally implemented "Integrated Science Courses" (ISCs) that combined rigorous training in the foundational sciences with meaningful clinical experiences. These courses integrated foundational sciences that could be leveraged in the clinical environment, utilized a variety of instructional modalities, and included quantitative and qualitative (competency-based milestones) student assessments. Each ISC underwent a rigorous quality improvement process that required input on foundational science content, student experience, and student performance assessment. RESULTS: Eleven ISCs were delivered to 173 students in AY15-16, with some students taking more than one ISC. Immediately after completing each course, 93% (n=222) of ISC enrollees completed a course evaluation. Students (91%; n=201) 'agreed' or 'strongly agreed' that foundational science learning informed and enriched the clinical experiences. Furthermore, 94% (n=209) of students thought that the clinical experiences informed and enriched the foundational science learning. Ninety-four percent of the students anticipated using the foundational science knowledge acquired in future clinical training and practice. CONCLUSION: The teaching of foundational sciences in the clinical workplace in the post-clerkship medical curriculum is challenging and resource-intensive, yet feasible. Additional experience with the model will inform the mix of courses as well as the breadth and depth of foundational science instruction that is necessary to foster scientifically-based clinical reasoning skills in each student.

Características del virus del dengue y su pronóstico bioclimático en el Departamento de Cortés / Characteristic of the dengue virus and its bioclimatic prognosis in Cortés Department

Se efectuó un estudio observacional, descriptivo y transversal en el Departamento de Cortés, en Honduras, durante el período de 2003 a 2013, con vistas a determinar las características del dengue en esta región, describir su historicidad y desarrollar un modelo matemático de pronóstico basado en variables bioclimáticas. En la serie el sexo no constituyó un factor predisponente, mientras que los grupos etarios de 5-9 y de 20-49 años, el ser habitante en Choloma, Villanueva y Puerto Cortés, resultaron elementos importantes en la aparición del dengue. Asimismo las formas graves de la enfermedad en niños y jóvenes indicaron una baja memoria inmunológica y/o varias exposiciones a serotipos del virus. Se obtuvo un patrón definido, cíclico-epidémico (de 4 a 5 años) y estacional, pues correspondía al período lluvioso de la región. Finalmente, se concluyó que las condiciones climáticas de Cortés están condicionando la transmisión del dengue, de manera que puede ser posible la predicción de los acontecimientos epidémicos(AU)

An observational, descriptive and cross-sectional study was carried out in Cortés Department, Honduras, during the period of 2003 at 2013, aimed at determining the characteristics of dengue in this region, describing its history and developing a prognosis mathematical model based on bioclimatic variables. In the series, sex didn't constitute a predisposing factor, while the age groups 5-9 and 20-49 years, being inhabitant in Choloma, Villanueva and Puerto Cortés were important elements in the emergence of dengue. Also the severe forms of the disease in children and young persons indicated a low immunologic memory and/or several exposures to serotypes of the virus. A defined, seasonal recurrent-epidemic pattern was obtained (of 4 to 5 years), because it corresponded to the rainy period of the region. Finally, it was concluded that the climate conditions of Cortés are conditioning the transmission of dengue, so that the prognosis of the epidemic events can be possible(AU(

Características del virus del dengue y su pronóstico bioclimático en el Departamento de Cortés / Characteristic of the dengue virus and its bioclimatic prognosis in Cortés Department

Se efectuó un estudio observacional, descriptivo y transversal en el Departamento de Cortés, en Honduras, durante el período de 2003 a 2013, con vistas a determinar las características del dengue en esta región, describir su historicidad y desarrollar un modelo matemático de pronóstico basado en variables bioclimáticas. En la serie el sexo no constituyó un factor predisponente, mientras que los grupos etarios de 5-9 y de 20-49 años, el ser habitante en Choloma, Villanueva y Puerto Cortés, resultaron elementos importantes en la aparición del dengue. Asimismo las formas graves de la enfermedad en niños y jóvenes indicaron una baja memoria inmunológica y/o varias exposiciones a serotipos del virus. Se obtuvo un patrón definido, cíclico-epidémico (de 4 a 5 años) y estacional, pues correspondía al período lluvioso de la región. Finalmente, se concluyó que las condiciones climáticas de Cortés están condicionando la transmisión del dengue, de manera que puede ser posible la predicción de los acontecimientos epidémicos

An observational, descriptive and cross-sectional study was carried out in Cortés Department, Honduras, during the period of 2003 at 2013, aimed at determining the characteristics of dengue in this region, describing its history and developing a prognosis mathematical model based on bioclimatic variables. In the series, sex didn't constitute a predisposing factor, while the age groups 5-9 and 20-49 years, being inhabitant in Choloma, Villanueva and Puerto Cortés were important elements in the emergence of dengue. Also the severe forms of the disease in children and young persons indicated a low immunologic memory and/or several exposures to serotypes of the virus. A defined, seasonal recurrent-epidemic pattern was obtained (of 4 to 5 years), because it corresponded to the rainy period of the region. Finally, it was concluded that the climate conditions of Cortés are conditioning the transmission of dengue, so that the prognosis of the epidemic events can be possible

CDX2 expression can predict response to neoadjuvant therapy in gastric carcinoma.

PURPOSE: Caudal-related homeobox transcription factor 2 (CDX2) has recently been proposed as a prognostic factor for gastric carcinoma. However and to the best of our knowledge, no previous report has analyzed CDX2 expression in patients with gastric adenocarcinoma receiving neoadjuvant therapy (NAT). PATIENTS, MATERIALS AND METHODS: This is a retrospective cohort study to analyze the potential role of CDX2 expression to predict response to NAT and prognosis. This study has enrolled 57 patients receiving chemotherapy for locally advanced gastric carcinoma. RESULTS: 59.6% of the patients were men; mean age was 64.96 years. Only 8% of the patients showed a complete response to therapy, 10% had grade 1, 28% grade 2, and 54% grade 3 regression, respectively, according to modified Ryan's criteria. On follow-up, 38.6% of the patients showed recurrence of disease (50% distant metastasis) and 28.1% eventually died of it. Twenty-three (40.4%) patients showed intense CDX2 expression. We found a statistically significant association between CDX2 expression and poor regression with NAT, but we found no association with outcome. DISCUSSION: Our study indicates that CDX2 expression can predict lack of response to NAT. Our results have not confirmed the association with prognosis shown in previous reports. CONCLUSIONS: Despite these preliminary results, furthermore studies are necessary to define the potential use of CDX2 in gastric carcinoma.

Novel Hybrid Phenotype Revealed in Small Cell Lung Cancer by a Transcription Factor Network Model That Can Explain Tumor Heterogeneity.

Small cell lung cancer (SCLC) is a devastating disease due to its propensity for early invasion and refractory relapse after initial treatment response. Although these aggressive traits have been associated with phenotypic heterogeneity, our understanding of this association remains incomplete. To fill this knowledge gap, we inferred a set of 33 transcription factors (TF) associated with gene signatures of the known neuroendocrine/epithelial (NE) and non-neuroendocrine/mesenchymal-like (ML) SCLC phenotypes. The topology of this SCLC TF network was derived from prior knowledge and was simulated using Boolean modeling. These simulations predicted that the network settles into attractors, or TF expression patterns, that correlate with NE or ML phenotypes, suggesting that TF network dynamics underlie the emergence of heterogeneous SCLC phenotypes. However, several cell lines and patient tumor specimens failed to correlate with either the NE or ML attractors. By flow cytometry, single cells within these cell lines simultaneously expressed surface markers of both NE and ML differentiation, confirming the existence of a "hybrid" phenotype. Upon exposure to standard-of-care cytotoxic drugs or epigenetic modifiers, NE and ML cell populations converged toward the hybrid state, suggesting possible escape from treatment. Our findings indicate that SCLC phenotypic heterogeneity can be specified dynamically by attractor states of a master regulatory TF network. Thus, SCLC heterogeneity may be best understood as states within an epigenetic landscape. Understanding phenotypic transitions within this landscape may provide insights to clinical applications. Cancer Res; 77(5); 1063-74. ©2016 AACR.

Altered TGF-α/ß signaling drives cooperation between breast cancer cell populations.

The role of tumor heterogeneity in regulating disease progression is poorly understood. We hypothesized that interactions between subpopulations of cancer cells can affect the progression of tumors selecting for a more aggressive phenotype. We developed an in vivo assay based on the immortalized nontumorigenic breast cell line MCF10A and its Ras-transformed derivatives AT1 (mildly tumorigenic) and CA1d (highly tumorigenic). CA1d cells outcompeted MCF10A, forming invasive tumors. AT1 grafts were approximately 1% the size of CA1d tumors when initiated using identical cell numbers. In contrast, CA1d/AT1 mixed tumors were larger than tumors composed of AT1 alone (100-fold) or CA1d (3-fold), suggesting cooperation in tumor growth. One of the mechanisms whereby CA1d and AT1 were found to cooperate was by modulation of TGF-α and TGF-ß signaling. Both of these molecules were sufficient to induce changes in AT1 proliferative potential in vitro. Reisolation of AT1 tumor-derived (AT1-TD) cells from these mixed tumors revealed that AT1-TD cells grew in vivo, forming tumors as large as tumorigenic CA1d cells. Cooperation between subpopulations of cancer epithelium is an understudied mechanism of tumor growth and invasion that may have implications on tumor resistance to current therapies.-Franco, O. E., Tyson, D. R., Konvinse, K. C., Udyavar, A. R., Estrada, L., Quaranta, V., Crawford, S. E., Hayward, S. W. Altered TGF-α/ß signaling drives cooperation between breast cancer cell populations.

An autoimmune polyglandular syndrome complicated with celiac disease and autoimmune hepatitis.

 Autoimmune polyglandular syndrome (APS) is a combination of different autoimmune diseases. The close relationship between immune-mediated disorders makes it mandatory to perform serological screening periodically in order to avoid delayed diagnosis of additional autoimmune diseases. We studied a patient with type 1 diabetes (T1D) who later developed an autoimmune thyroid disease (ATD) and was referred to our hospital with a serious condition of his clinical status. The patient was suffering from an advance stage of celiac disease (CD), the delay in its diagnosis and in the establishment of a gluten-free dietled the patient to a severe proteincalorie malnutrition. Later, the patient developed an autoimmune hepatitis (AIH). We consider that clinical deterioration in patients with APS should alert physicians about the possible presence of other immune-mediated diseases. Periodic screening for autoantibodies would help to prevent delayed diagnosis and would improve patient's quality of life.

Cobertura de vacunación en edad pediátrica frente al virus del papiloma humano (VPH) en franjas no financiadas en las areas básicas de salud (ABS) / No disponible

No disponible

Co-expression network analysis identifies Spleen Tyrosine Kinase (SYK) as a candidate oncogenic driver in a subset of small-cell lung cancer.

BACKGROUND: Oncogenic mechanisms in small-cell lung cancer remain poorly understood leaving this tumor with the worst prognosis among all lung cancers. Unlike other cancer types, sequencing genomic approaches have been of limited success in small-cell lung cancer, i.e., no mutated oncogenes with potential driver characteristics have emerged, as it is the case for activating mutations of epidermal growth factor receptor in non-small-cell lung cancer. Differential gene expression analysis has also produced SCLC signatures with limited application, since they are generally not robust across datasets. Nonetheless, additional genomic approaches are warranted, due to the increasing availability of suitable small-cell lung cancer datasets. Gene co-expression network approaches are a recent and promising avenue, since they have been successful in identifying gene modules that drive phenotypic traits in several biological systems, including other cancer types. RESULTS: We derived an SCLC-specific classifier from weighted gene co-expression network analysis (WGCNA) of a lung cancer dataset. The classifier, termed SCLC-specific hub network (SSHN), robustly separates SCLC from other lung cancer types across multiple datasets and multiple platforms, including RNA-seq and shotgun proteomics. The classifier was also conserved in SCLC cell lines. SSHN is enriched for co-expressed signaling network hubs strongly associated with the SCLC phenotype. Twenty of these hubs are actionable kinases with oncogenic potential, among which spleen tyrosine kinase (SYK) exhibits one of the highest overall statistical associations to SCLC. In patient tissue microarrays and cell lines, SCLC can be separated into SYK-positive and -negative. SYK siRNA decreases proliferation rate and increases cell death of SYK-positive SCLC cell lines, suggesting a role for SYK as an oncogenic driver in a subset of SCLC. CONCLUSIONS: SCLC treatment has thus far been limited to chemotherapy and radiation. Our WGCNA analysis identifies SYK both as a candidate biomarker to stratify SCLC patients and as a potential therapeutic target. In summary, WGCNA represents an alternative strategy to large scale sequencing for the identification of potential oncogenic drivers, based on a systems view of signaling networks. This strategy is especially useful in cancer types where no actionable mutations have emerged.

Effects of intracellular organelles on the apparent diffusion coefficient of water molecules in cultured human embryonic kidney cells.

The apparent diffusion coefficient (ADC) of water in tissues is dependent on the size and spacing of structures in the cellular environment and has been used to characterize pathological changes in stroke and cancer. However, the factors that affect ADC values remain incompletely understood. Measurements of ADC are usually made using relatively long diffusion times; so they reflect the integrated effects of cellular structures over a broad range of spatial scales. We used temporal diffusion spectroscopy to study diffusion in packed cultured human embryonic kidney cells over a range of effective diffusion times following microtubule and actin/cytoskeleton depolymerization and disassembly of the Golgi complex. While Golgi disruption did not change ADC, depolymerization of the microtubule and the actin filament networks caused small decreases in ADC at short diffusion times only. Temporal diffusion spectroscopy provided a novel way to assess intracellular influences on the diffusion properties of tissue water.

Linking changes in epithelial morphogenesis to cancer mutations using computational modeling.

Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological changes at the cellular and tissue scales, respectively. Elevated proliferation and loss of epithelial polarization are the two most noticeable changes in cell phenotypes during this process. As a result, many three-dimensional cultures of tumorigenic clones show highly aberrant morphologies when compared to regular epithelial monolayers enclosing the hollow lumen (acini). In order to shed light on phenotypic changes associated with tumor cells, we applied the bio-mechanical IBCell model of normal epithelial morphogenesis quantitatively matched to data acquired from the non-tumorigenic human mammary cell line, MCF10A. We then used a high-throughput simulation study to reveal how modifications in model parameters influence changes in the simulated architecture. Three parameters have been considered in our study, which define cell sensitivity to proliferative, apoptotic and cell-ECM adhesive cues. By mapping experimental morphologies of four MCF10A-derived cell lines carrying different oncogenic mutations onto the model parameter space, we identified changes in cellular processes potentially underlying structural modifications of these mutants. As a case study, we focused on MCF10A cells expressing an oncogenic mutant HER2-YVMA to quantitatively assess changes in cell doubling time, cell apoptotic rate, and cell sensitivity to ECM accumulation when compared to the parental non-tumorigenic cell line. By mapping in vitro mutant morphologies onto in silico ones we have generated a means of linking the morphological and molecular scales via computational modeling. Thus, IBCell in combination with 3D acini cultures can form a computational/experimental platform for suggesting the relationship between the histopathology of neoplastic lesions and their underlying molecular defects.

Microenvironmental independence associated with tumor progression.

Tumor-microenvironment interactions are increasingly recognized to influence tumor progression. To understand the competitive dynamics of tumor cells in diverse microenvironments, we experimentally parameterized a hybrid discrete-continuum mathematical model with phenotypic trait data from a set of related mammary cell lines with normal, transformed, or tumorigenic properties. Surprisingly, in a resource-rich microenvironment, with few limitations on proliferation or migration, transformed (but not tumorigenic) cells were most successful and outcompeted other cell types in heterogeneous tumor simulations. Conversely, constrained microenvironments with limitations on space and/or growth factors gave a selective advantage to phenotypes derived from tumorigenic cell lines. Analysis of the relative performance of each phenotype in constrained versus unconstrained microenvironments revealed that, although all cell types grew more slowly in resource-constrained microenvironments, the most aggressive cells were least affected by microenvironmental constraints. A game theory model testing the relationship between microenvironment resource availability and competitive cellular dynamics supports the concept that microenvironmental independence is an advantageous cellular trait in resource-limited microenvironments.

Nest expansion assay: a cancer systems biology approach to in vitro invasion measurements.

BACKGROUND: Traditional in vitro cell invasion assays focus on measuring one cell parameter at a time and are often less than ideal in terms of reproducibility and quantification. Further, many techniques are not suitable for quantifying the advancing margin of collectively migrating cells, arguably the most important area of activity during tumor invasion. We have developed and applied a highly quantitative, standardized, reproducible Nest Expansion Assay (NEA) to measure cancer cell invasion in vitro, which builds upon established wound-healing techniques. This assay involves creating uniform circular "nests" of cells within a monolayer of cells using a stabilized, silicone-tipped drill press, and quantifying the margin expansion into an overlaid extracellular matrix (ECM)-like component using computer-assisted applications. FINDINGS: The NEA was applied to two human-derived breast cell lines, MCF10A and MCF10A-CA1d, which exhibit opposite degrees of tumorigenicity and invasion in vivo. Assays were performed to incorporate various microenvironmental conditions, in order to test their influence on cell behavior and measures. Two types of computer-driven image analysis were performed using Java's freely available ImageJ software and its FracLac plugin to capture nest expansion and fractal dimension, respectively - which are both taken as indicators of invasiveness. Both analyses confirmed that the NEA is highly reproducible, and that the ECM component is key in defining invasive cell behavior. Interestingly, both analyses also detected significant differences between non-invasive and invasive cell lines, across various microenvironments, and over time. CONCLUSION: The spatial nature of the NEA makes its outcome susceptible to the global influence of many cellular parameters at once (e.g., motility, protease secretion, cell-cell adhesion). We propose the NEA as a mid-throughput technique for screening and simultaneous examination of factors contributing to cancer cell invasion, particularly suitable for parameterizing and validating Cancer Systems Biology approaches such as mathematical modeling.

A mathematical model quantifies proliferation and motility effects of TGF-ß on cancer cells.

Transforming growth factor (TGF)-ß is known to have properties of both a tumour suppressor and a tumour promoter. While it inhibits cell proliferation, it also increases cell motility and decreases cell-cell adhesion. Coupling mathematical modelling and experiments, we investigate the growth and motility of oncogene-expressing human mammary epithelial cells under exposure to TGF-ß. We use a version of the well-known Fisher-Kolmogorov equation, and prescribe a procedure for its parametrisation. We quantify the simultaneous effects of TGF-ß to increase the tendency of individual cells and cell clusters to move randomly and to decrease overall population growth. We demonstrate that in experiments with TGF-ß treated cells in vitro, TGF-ß increases cell motility by a factor of 2 and decreases cell proliferation by a factor of 1/2 in comparison with untreated cells.