Engineering chromosome rearrangements in cancer.

The identification of large chromosomal rearrangements in cancers has multiplied exponentially over the last decade. These complex and often rare genomic events have traditionally been challenging to study, in part owing to lack of tools that efficiently engineer disease-associated inversions, deletions and translocations in model systems. The emergence and refinement of genome editing technologies, such as CRISPR, have significantly expanded our ability to generate and interrogate chromosomal aberrations to better understand the networks that govern cancer growth. Here we review how existing technologies are employed to faithfully model cancer-associated chromosome rearrangements in the laboratory, with the ultimate goal of developing more accurate pre-clinical models of and therapeutic strategies for cancers driven by these genomic events.

The Landmark Series: Chemotherapy for Non-Metastatic Colon Cancer.

Micrometastatic disease that is present at the time of surgery is responsible for the overwhelming majority of deaths in patients with what is otherwise perceived to be local and regional colon cancer. The goal of perioperative therapy is to eliminate microscopic residual disease that would otherwise be left behind following surgery. A secondary goal specific to neoadjuvant (preoperative) therapy is to downstage tumors deemed potentially not amenable to an R0 resection on the basis of a suspected T4b primary (locally invading into a surrounding structure). In this landmark series paper, we review the current standard for perioperative therapy in patients with colon cancer.

Role of CYP3A4 in bone marrow microenvironment-mediated protection of FLT3/ITD AML from tyrosine kinase inhibitors.

An intriguing aspect of the clinical activity of FMS-like tyrosine kinase 3 inhibitors (FLT3 TKIs) is their apparent higher activity against peripheral blasts from FLT3/internal tandem duplication (ITD) acute myeloid leukemia than marrow disease in the same patients. Accordingly, studies showed that the bone marrow microenvironment plays a role in FLT3 TKI resistance, although the underlying mechanisms are unclear. We recently identified a previously undescribed mechanism by which the bone marrow microenvironment can contribute to drug resistance: expression of cytochrome P450 enzymes (CYPs). In fact, bone marrow stromal cells (BMSCs) expressed most CYPs, including CYP3A4. Because hepatic CYP3A4 plays a role in the inactivation of several FLT3 TKIs, we explored the potential role of CYP3A4 in bone marrow microenvironment-mediated FLT3 TKI resistance. We found that CYP3A4 plays a major role in BMSC-mediated inhibition in the activity of 3 different FLT3 TKIs (sorafenib, quizartinib, and gilteritinib) against FLT3/ITD acute myeloid leukemia (AML). Furthermore, clarithromycin, a clinically active CYP3A4 inhibitor, significantly reversed the protective effects of BMSCs. We show, for the first time, that bone marrow stromal CYP3A4 contributes to FLT3 TKI resistance in the bone marrow. These results suggest that combining FLT3 TKIs with CYP3A4 inhibitors could be a promising strategy toward improving the activity of FLT3 TKIs.

Nutritional Regulation of Intestinal Stem Cells.

Dietary composition and calorie intake are major determinants of health and disease. Calorie restriction promotes metabolic changes that favor tissue regeneration and is arguably the most successful and best-conserved antiaging intervention. Obesity, in contrast, impairs tissue homeostasis and is a major risk factor for the development of diseases including cancer. Stem cells, the central mediators of tissue regeneration, integrate dietary and energy cues via nutrient-sensing pathways to maintain growth or respond to stress. We discuss emerging data on the effects of diet and nutrient-sensing pathways on intestinal stem cells, as well as their potential application in the development of regenerative and therapeutic interventions.

Retinoic acid, CYP26, and drug resistance in the stem cell niche.

The bone marrow niche is essential for hematopoietic stem cells to maintain lifelong blood production by balancing their self-renewal and differentiation. Hematologic malignancies have a similar hierarchical organization to their normal counterparts, with rare populations of cancer stem cells that rely on the microenvironment to survive and propagate their differentiated malignant progenitor cells. Cancer cells alter their microenvironment to create a supportive niche, where they endure chemotherapy, survive as minimal residual disease (MRD), and eventually prevail at relapse. Powerful morphogens, such as retinoids, Wnt/ßcatenin, Notch, and Hedgehog, control stem cell fates across tissues, including normal and malignant hematopoiesis. The molecular conversations between these pathways and the mechanisms that control their activity and create gradients at cellular scale remain a mystery. Here, we discuss accumulating evidence suggesting that cytochrome P450 (CYP26), the primary retinoid-inactivating enzyme, plays a critical role in the integration of two of these molecular programs: the retinoid and Hedgehog pathways. Induction of stromal CYP26 by either one of these pathways limits retinoic acid concentration in the stem cell niche, with profound effects on tissue homeostasis and drug resistance. Bypassing this gatekeeping mechanism holds promise for overcoming drug resistance and improving clinical outcomes in hematological malignancies and cancer in general.

Hedgehog and retinoid signaling alters multiple myeloma microenvironment and generates bortezomib resistance.

Interactions between multiple myeloma (MM) cells and the BM microenvironment play a critical role in bortezomib (BTZ) resistance. However, the mechanisms involved in these interactions are not completely understood. We previously showed that expression of CYP26 in BM stromal cells maintains a retinoic acid-low (RA-low) microenvironment that prevents the differentiation of normal and malignant hematopoietic cells. Since a low secretory B cell phenotype is associated with BTZ resistance in MM and retinoid signaling promotes plasma cell differentiation and Ig production, we investigated whether stromal expression of the cytochrome P450 monooxygenase CYP26 modulates BTZ sensitivity in the BM niche. CYP26-mediated inactivation of RA within the BM microenvironment prevented plasma cell differentiation and promoted a B cell-like, BTZ-resistant phenotype in human MM cells that were cocultured on BM stroma. Moreover, paracrine Hedgehog secretion by MM cells upregulated stromal CYP26 and further reinforced a protective microenvironment. These results suggest that crosstalk between Hedgehog and retinoid signaling modulates BTZ sensitivity in the BM niche. Targeting these pathological interactions holds promise for eliminating minimal residual disease in MM.

Adenoma de células basales parotídeo: reporte de un caso, manejo terapéutico y revisión de la literatura / Basal cell adehoma of the parotid gland: report of a case, therapeutic management and review of the literature

El adenoma de células basales de las glándulas salivares es un tipo deadenoma de aparición infrecuente. La localización más habitual es la superficie de la glándula parótida. Suele debutar clínicamente como una masa fi rme y desplazable de crecimiento lento, asintomática, que puede distinguirse a la palpación en el examen clínico. Afecta más a las mujeres, entre 35 y 80 años. Histológicamente: se observan cordonesy trabéculas de células epiteliales delimitadas por células basaloides y formaciones microquísticas, sin componente mixocondroide del tumormixto, como el presente caso. Se puede dividir en cuatro subtipos atendiendoa su morfología: sólido, tubular, trabecular y membranoso. El tratamiento preferido es la escisión quirúrgica conservadora que incluyeun reborde o margen de tejido normal no afectado. Describimos un caso clínico de adenoma de células basales de la glándula parótida; el hallazgo de esta patología en particular, es muy rara y poco documentada, además realizamos una revisión de la literatura y discutimos el manejo terapéutico y conservador de esta rara enfermedad.

Basal cell adenoma of the salivary glands is a rarely seen type of adenoma.Its most frequent location is the surface of the parotid gland. Itusually appears as a fi rm, mobile, slow-growing asymptomatic mass,which can be detected by palpation during clinical examination. Itis more prevalent in women between the age of 35 and 80 years.Histologically, cords and trabeculae of epithelial cells bounded bybasaloid cells and microcystic formations are visible, without themyxochondroid component of mixed tumors, as in the present case.The basal cell adenoma can be divided into four subtypes based onmorphology: solid, tubular, trabecular and membranous. The treatmentof choice is conservative surgical excision that includes a rimor margin of normal uninvolved tissue. We describe a clinical case ofbasal cell adenoma of the parotid gland, a particular disease that isvery rarely found and seldom documented. We also perform a reviewof the literature and discuss the conservative therapeutic managementof this unusual disease.

All-Trans Retinoic Acid Activity in Acute Myeloid Leukemia: Role of Cytochrome P450 Enzyme Expression by the Microenvironment.

Differentiation therapy with all-trans retinoic acid (atRA) has markedly improved outcome in acute promyelocytic leukemia (APL) but has had little clinical impact in other AML sub-types. Cell intrinsic mechanisms of resistance have been previously reported, yet the majority of AML blasts are sensitive to atRA in vitro. Even in APL, single agent atRA induces remission without cure. The microenvironment expression of cytochrome P450 (CYP)26, a retinoid-metabolizing enzyme was shown to determine normal hematopoietic stem cell fate. Accordingly, we hypothesized that the bone marrow (BM) microenvironment is responsible for difference between in vitro sensitivity and in vivo resistance of AML to atRA-induced differentiation. We observed that the pro-differentiation effects of atRA on APL and non-APL AML cells as well as on leukemia stem cells from clinical specimens were blocked by BM stroma. In addition, BM stroma produced a precipitous drop in atRA levels. Inhibition of CYP26 rescued atRA levels and AML cell sensitivity in the presence of stroma. Our data suggest that stromal CYP26 activity creates retinoid low sanctuaries in the BM that protect AML cells from systemic atRA therapy. Inhibition of CYP26 provides new opportunities to expand the clinical activity of atRA in both APL and non-APL AML.

Human bone marrow niche chemoprotection mediated by cytochrome P450 enzymes.

Substantial evidence now demonstrates that interactions between the tumor microenvironment and malignant cells are a critical component of clinical drug resistance. However, the mechanisms responsible for microenvironment-mediated chemoprotection remain unclear. We showed that bone marrow (BM) stromal cytochrome P450 (CYP)26 enzymes protect normal hematopoietic stem cells (HSCs) from the pro-differentiation effects of retinoic acid. Here, we investigated if stromal expression of CYPs is a general mechanism of chemoprotection. We found that similar to human hepatocytes, human BM-derived stromal cells expressed a variety of drug-metabolizing enzymes. CYP3A4, the liver's major drug-metabolizing enzyme, was at least partially responsible for BM stroma's ability to protect multiple myeloma (MM) and leukemia cells from bortezomib and etoposide, respectively, both in vitro and in vivo. Moreover, clarithromycin overcame stromal-mediated MM resistance to dexamethasone, suggesting that CYP3A4 inhibition plays a role in its ability to augment the activity of lenalidomide and dexamethasone as part of the BiRd regimen. We uncovered a novel mechanism of microenvironment-mediated drug resistance, whereby the BM niche creates a sanctuary site from drugs. Targeting these sanctuaries holds promise for eliminating minimal residual tumor and improving cancer outcomes.

Thymopoietin Beta and Gamma Isoforms as a Potential Diagnostic Molecular Marker for Breast Cancer: Preliminary Data.

Thymopoietin (TMPO) is an inner nuclear membrane protein, the coding gene named equally, can give arise to six isoforms by alternative splicing. This gene has been found up regulated in several types of cancer. At present work, we evaluated the TMPO isoforms generated by alternative splicing as well as the protein signal detection in breast cancer samples. TMPO expression was analyzed by immunohistochemistry in tissue microarray containing 46 breast tissue samples including normal (n = 6), benign lesions (n = 18) (fibroadenomas (n = 6), fibrocystic changes (n = 6), ductal hyperplasias (n = 6)) and breast carcinoma (n = 22). Isoforms -α, -ß and -γ of TMPO were evaluated using RT-PCR; clinical-pathological correlation analysis were done by mean of X(2). Neither the normal nor the benign lesions of the breast showed positive TMPO immunodetection, whilst 45 % of the breast carcinomas were immunopositive (p = 0.000), nine of ten positives carcinomas correspond to the Luminal A subtype. Further, alpha isoform was present in all breast samples analyzed; however, beta and gamma isoforms were only present in ten (p = 0.003) and 17 (p = 0.000), respectively, in the breast cancer samples. According with the present data, we suggest that TMPOß and -γ isoforms could provide a potential reliable diagnostic marker for breast cancer.

Associating clinical archetypes through UMLS Metathesaurus term clusters.

Clinical archetypes are modular definitions of clinical data, expressed using standard or open constraint-based data models as the CEN EN13606 and openEHR. There is an increasing archetype specification activity that raises the need for techniques to associate archetypes to support better management and user navigation in archetype repositories. This paper reports on a computational technique to generate tentative archetype associations by mapping them through term clusters obtained from the UMLS Metathesaurus. The terms are used to build a bipartite graph model and graph connectivity measures can be used for deriving associations.

Estudio de toxicidad del péptido beta-amiloide en linfocitos humanos / Beta amyloid peptide toxicity in human lymphocytes

Introducción: la enfermedad de Alzheimer (EA) es uno de los problemas sociosanitarios más importantes actualmente. Se considera la toxicidad del péptido beta-amiloide la clave de su patogenia. Cada vez es más importante conseguir marcadores periféricos de la enfermedad para avanzar en su conocimiento y de sus posibles dianas terapéuticas. Con este estudio pretendemos valorar la idoneidad de los linfocitos como modelo en el que estudiar la toxicidad del beta-amiloide. Material y métodos: se reclutó a 6 voluntarios sanos, 3 varones y 3 mujeres, con edades comprendidas entre los 25 y 35 años, sin antecedentes familiares de EA. Se les realizó una extracción sanguínea de donde se aislaron los linfocitos que posteriormente se incubaron con beta-amiloide 1-42 durante 6 h. Se utilizó la microscopia confocal y la citometría de flujo para estudiar, como marcadores de toxicidad celular, la apoptosis, el potencial de membrana mitocondrial y el número de mitocondrias. Resultados: encontramos un aumento de muerte celular en sus distintos estadios (apoptosis temprana y tardía) así como una disminución de mitocondrias en los linfocitos incubados con el péptido beta-amiloide. Observamos un mayor daño celular en los linfocitos de los varones que en las mujeres, probablemente por el efecto protector de los estrógenos. Conclusiones: los linfocitos son un buen modelo para estudiar la toxicidad celular del péptido beta-amiloide

Introduction: Alzheimer's disease is a major health concern. The toxicity of the beta amyloid peptide is a key pathogenic event in the development of this disease. Finding peripheral markers for Alzheimer's disease is an important step for the early detection and treatment of this disease. The aim of the present study was to evaluate the utility of lymphocytes as a peripheral model for the study of beta amyloid toxicity. Material and methods: six healthy volunteers (three men and three women), aged 25-35 years, without a family history of Alzheimer's disease were recruited. Peripheral blood lymphocytes were obtained and incubated with 10 micromolar beta amyloid peptide for 6 hours. Confocal microscopy and flow cytometry were used to determine the rate of apoptosis, mitochondrial membrane potential, and the number of mitochondria. Results: incubation of lymphocytes with beta amyloid peptide caused an increase in cell death (apoptosis plus necrosis) as well as a decrease in the number of mitochondria. The peptide caused more damage to cells from men than to those from women, probably due to the protective effect of estrogens. Conclusions: lymphocytes are a good model for studying cellular susceptibility to beta amyloid peptide