SPARC Controls Melanoma Cell Plasticity through Rac1.

Cell transition to a more aggressive mesenchymal-like phenotype is a hallmark of cancer progression that involves different steps and requires tightly regulated cell plasticity. SPARC (Secreted Protein Acidic and Rich in Cysteine) is a matricellular protein that promotes this transition in various malignant cell types, including melanoma cells. We found that suppression of SPARC expression in human melanoma cells compromised cell migration, adhesion, cytoskeleton structure, and cell size. These changes involved the Akt/mTOR pathway. Re-expression of SPARC or protein addition restored all the cell features. Suppression of SPARC expression was associated with increased Rac1-GTP levels and its membrane localization. Expression of the dominant negative mutant of Rac1 counteracted almost all the changes observed in SPARC-deficient cells. Overall, these data suggest that most of the SPARC-mediated effects occurred mainly through the blockade of Rac1 activity.

PFT1, the MED25 subunit of the plant Mediator complex, promotes flowering through CONSTANS dependent and independent mechanisms in Arabidopsis.

Two aspects of light are very important for plant development: the length of the light phase or photoperiod and the quality of incoming light. Photoperiod detection allows plants to anticipate the arrival of the next season, whereas light quality, mainly the red to far-red ratio (R:FR), is an early signal of competition by neighbouring plants. phyB represses flowering by antagonising CO at the transcriptional and post-translational levels. A low R:FR decreases active phyB and consequently increases active CO, which in turn activates the expression of FT, the plant florigen. Other phytochromes like phyD and phyE seem to have redundant roles with phyB. PFT1, the MED25 subunit of the plant Mediator complex, has been proposed to act in the light-quality pathway that regulates flowering time downstream of phyB. However, whether PFT1 signals through CO and its specific mechanism are unclear. Here we show that CO-dependent and -independent mechanisms operate downstream of phyB, phyD and phyE to promote flowering, and that PFT1 is equally able to promote flowering by modulating both CO-dependent and -independent pathways. Our data are consistent with the role of PFT1 as an activator of CO transcription, and also of FT transcription, in a CO-independent manner. Our transcriptome analysis is also consistent with CO and FT genes being the most important flowering targets of PFT1. Furthermore, comparison of the pft1 transcriptome with transcriptomes after fungal and herbivore attack strongly suggests that PFT1 acts as a hub, integrating a variety of interdependent environmental stimuli, including light quality and jasmonic acid-dependent defences.

Psychometric evaluation of a Spanish language version of the Screen for Caregiver Burden (SCB) in caregivers of patients with mixed, vascular and Alzheimer's dementia.

AIMS AND OBJECTIVES: To validate a Spanish language version of the Screen for Caregiver Burden, the full-length or long (25-item) and short (seven-item) versions in Mexican caregivers of patients with mixed, vascular and Alzheimer's dementia. BACKGROUND: Patients with dementia display impaired executive function and neuropsychiatric symptoms such as behavioural changes and sleep disturbances. These symptoms can make patients become more dependent. The experience of caregiving for patients under these conditions is burdensome. It is important to detect this burden to protect both the caregiver and the patient from negative outcomes. DESIGN: Survey. METHODS: Participants were 143 primary caregivers of patients with dementia and 30 caregivers of older adults without dementia in two hospitals in Mexico City. RESULTS: The internal reliability was Cronbach's α=0·89 and 0·82 for the 25-item and the seven-item versions, respectively. The item-total correlations for two Screen for Caregiver Burden versions were significant from r=0·26 to r=0·77 p<0·001. The test-retest was ICC=0·78 p<0·001; CI 95% (0·55-0·89) and ICC=0·72 p<0·001; CI 95% (0·41-0·86) for the 25-item and the seven-item, respectively. We found from non-significant to highly significant correlations between two Screen for Caregiver Burden versions and other measures ranged. Validity of known groups showed that the caregivers of demented patients experienced more burden than those caring for non-demented patients. CONCLUSIONS: Given these psychometric properties, both versions of the Screen for Caregiver Burden are valid tools and can be reliably used to assess the presence and level of caregiver burden in caregivers of demented patients. RELEVANCE TO CLINICAL PRACTICE: The Screen for Caregiver Burden in the Spanish Language can be used in clinical practice to detect caregiver burden in family members. We recommend using the long or full-length version when the objective is to assess the caregiver burden carefully and the short version (seven-item) as a screening method of caregiver burden that requires attention.

[Hypoglycemia in the elderly with diabetes mellitus]. / Hipoglucemia en el anciano con diabetes mellitus.

Aging is associated with an increasing prevalence of chronic diseases, including type 2 diabetes mellitus and its chronic and acute complications. With changes observed in diabetes mellitus treatment goals and the lower levels of glycosylated hemoglobin recommended, the prevalence of hypoglycemia especially in patients treated with insulin has increased. Aging and changes in the physiologic reserves generate a decreased perception of symptoms associated with hypoglycemia, increasing the risk of unawareness or severe episodes. Traditionally, age was a risk factor for hypoglycemia, but in the population over 60 years, multiple comorbidities like chronic heart failure, malnutrition and renal failure are associated with increased risk of developing this acute complication. It is necessary to train doctors and nurses from all levels of care to recognize the specific clinical manifestation of low blood glucose that allow early detection and treatment, because this complication is associated with an increased hospital and 1-year after discharge mortality, with falls and cognitive impairment that directly affect the independence and functionality of older persons.

[Inflammaging. Aging inflammatory origin]. / Inflammaging. Envejecimiento de origen inflamatorio.

The association between the increase in life expectancy in humans and age-related changes in the immune system promotes that individuals are exposed longer to endogenous and environment antigens which allows an activation of the innate immune system and the subsequent establishment of a low grade chronic inflammation state with an increased expression of proinflammatory cytokines (tumor necrosis factor alpha, interleukin 6, etc.). This inflammatory state referred as inflammaging is characterized by a inflammatory origin of aging given by the activation of cellular systems responsible of gene promotion and suppression as the nuclear factor kappa B, sirtuins, forkhead box O and KLOTHO, who are directly or indirectly involved in cellular mechanisms of resistance to oxidative stress, apoptosis and nucleic acids transcriptional mistakes repair. The activation of these cellular systems is associated with the pathogenesis of several chronic and degenerative diseases such as Alzheimer's disease, late-onset diabetes or cardiovascular diseases. However, we are placed in a crossroad because we can not establish whether this inflammatory state observed in the aging process is responsible of development of degenerative diseases or if the presences of these chronic diseases are responsible for this inflammatory state of aging. Evidence in centenarians who are healthy and have preserved functional status has shown that there is a chronic inflammatory state present among them but is balanced by a higher expression of anti-inflammatory molecules.

A complementary role for ELF3 and TFL1 in the regulation of flowering time by ambient temperature.

Plants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Sub-optimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one requiring TFL1 and another requiring ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants, which have a constitutive photoperiodic response. In contrast to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. Gene expression profiles revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes, and identified CCA1 and SOC1/AGL20 as being important cross-talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling.

[Special considerations for patients over 60 years with asthma]. / Consideraciones especiales en pacientes mayores de 60 años con asma.

The population over 60 years is increasing because of the demographic transition, the aging of the human body and the changes on functional reserve make that the clinical manifestations are different and the tools used for diagnosis may not have the same sensitivity as in younger people. Asthma remains a prevalent disease in the elderly and compromises their functionality and independence. Aging produces that tools such as spirometry and challenge test with bronchodilator provide results than can't be evaluated with those parameters developed in younger people complicating the diagnosis of asthma in this population. Studies in elderly with asthma have shown that the proportion of patients with an atopic component are lower and the kind of symptoms and complications are varied, which makes the differential diagnosis with multiple comorbidities, especially from other heart and lung diseases. Despite the good response to stepped treatment in the elderly, this population requires a deep evaluation of possible drug interactions and potentially inappropriate medication related with the large numbers of drugs they usually consume, making an interdisciplinary treatment imperative.

SPARC endogenous level, rather than fibroblast-produced SPARC or stroma reorganization induced by SPARC, is responsible for melanoma cell growth.

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein whose overexpression in malignant or tumor-stromal cells is often associated with increased aggressiveness and bad prognosis in a wide range of human cancer types, particularly melanoma. We established the impact that changes in the level of SPARC produced by malignant cells and neighboring stromal cells have on melanoma growth. Melanoma cell growth in monolayer was only slightly affected by changes in SPARC levels. However, melanoma growth in spheroids was strongly inhibited upon SPARC hyperexpression and conversely enhanced when SPARC expression was downregulated. Interestingly, SPARC overexpression in neighboring fibroblasts had no effect on spheroid growth irrespective of SPARC levels expressed by the melanoma cells, themselves. Downregulation of SPARC expression in melanoma cells induced their rejection in vivo through a mechanism mediated exclusively by host polymorphonuclear cells. On the other hand, SPARC hyperexpression enhanced vascular density, collagen deposition, and fibroblast recruitment in the surrounding stroma without affecting melanoma growth. In agreement with the in vitro data, overexpression of SPARC in co-injected fibroblasts did not affect melanoma growth in vivo. All the data indicate that melanoma growth is not subject to regulation by exogenous SPARC, nor by stromal organization, but only by SPARC levels produced by the malignant cells themselves.

Model based analysis of real-time PCR data from DNA binding dye protocols.

BACKGROUND: Reverse transcription followed by real-time PCR is widely used for quantification of specific mRNA, and with the use of double-stranded DNA binding dyes it is becoming a standard for microarray data validation. Despite the kinetic information generated by real-time PCR, most popular analysis methods assume constant amplification efficiency among samples, introducing strong biases when amplification efficiencies are not the same. RESULTS: We present here a new mathematical model based on the classic exponential description of the PCR, but modeling amplification efficiency as a sigmoidal function of the product yield. The model was validated with experimental results and used for the development of a new method for real-time PCR data analysis. This model based method for real-time PCR data analysis showed the best accuracy and precision compared with previous methods when used for quantification of in-silico generated and experimental real-time PCR results. Moreover, the method is suitable for the analyses of samples with similar or dissimilar amplification efficiency. CONCLUSION: The presented method showed the best accuracy and precision. Moreover, it does not depend on calibration curves, making it ideal for fully automated high-throughput applications.

Platelet-endothelial cell adhesion molecule-1 (CD31) recycles and induces cell growth inhibition on human tumor cell lines.

CD31 (PECAM-1) is a 130-kDa member of the immunoglobulin gene superfamily expressed on endothelial cells, platelets, and most leukocytes. This report demonstrates by Western Blot and immunofluorescence that some human melanoma and adenocarcinoma cell lines express CD31 on the cell surface. The surface expression of CD31 was regulated by cell-cell contact, being higher on sparse and spontaneously detached cells. Indeed, fixing and permeabilizing tumor cells revealed a cytoplasmic pool, which was confirmed by confocal microscopy. Some of the plasma surface molecule is endocytosed following mAb binding. Engagement of CD31 on tumor cells via domain-3 inhibited proliferation by inducing cell apoptosis. On the other hand, apoptosis does not increase CD31 expression. Overall, these results indicate that there is an intracellular pool of CD31 on some tumor cells, which modulates CD31 surface expression and its role in cancer cell growth and metastasis. Thus, the expression of CD31 and its role in cell survival in some tumor cells appears to differ from endothelial cells.

Secreted protein acidic and rich in cysteine produced by human melanoma cells modulates polymorphonuclear leukocyte recruitment and antitumor cytotoxic capacity.

The expression of secreted protein acidic and rich in cysteine (SPARC) has been associated with the malignant progression of different types of human cancer. SPARC was associated with tumor cell capacity to migrate and invade, although its precise role in tumor progression is still elusive. In the present study, we show that SPARC produced by melanoma cells modulates the antitumor activity of polymorphonuclear leukocytes (PMN). Administration to nude mice of human melanoma cells in which SPARC expression was transiently or stably knocked down by antisense RNA (SPARC-sup cells) promoted PMN recruitment and obliterated tumor growth even when SPARC-sup cells accounted for only 10% of injected malignant cells. In addition, SPARC-sup cells stimulated the in vitro migration and triggered the antimelanoma cytotoxic capacity of human PMN, an effect that was reverted in the presence of SPARC purified from melanoma cells or by reexpressing SPARC in SPARC-sup cells. Leukotrienes, interleukin 8, and growth-related oncogene, in combination with Fas ligand and interleukin 1, mediated SPARC effects. These data indicate that SPARC plays an essential role in tumor evasion from immune surveillance through the inhibition of the antitumor PMN activity.

Targeted inhibition of galectin-1 gene expression in tumor cells results in heightened T cell-mediated rejection; A potential mechanism of tumor-immune privilege.

Despite the existence of tumor-specific immune cells, most tumors have devised strategies to avoid immune attack. We demonstrate here that galectin-1 (Gal-1), a negative regulator of T cell activation and survival, plays a pivotal role in promoting escape from T cell-dependent immunity, thus conferring immune privilege to tumor cells. Blockade of immunosuppressive Gal-1 in vivo promotes tumor rejection and stimulates the generation of a tumor-specific T cell-mediated response in syngeneic mice, which are then able to resist subsequent challenge with wild-type Gal-1-sufficient tumors. Our data indicate that Gal-1 signaling in activated T cells constitutes an important mechanism of tumor-immune escape and that blockade of this inhibitory signal can allow for and potentiate effective immune responses against tumor cells, with profound implications for cancer immunotherapy.

Toloxatona y depresión / Toloxatone and depression

Los autores informan la experiencia recogida con la utilización, en 101 pacientes deprimidos, de un antidepressivo de segunda generación, la toloxatona: molécula original dotada de una actividad inhibidora específica y reversible de la MAO A. Al momento de la admisión, los 101 pacientes con enfermedad depresiva presentaban un score mínimo de 20 puntos en al Escala de Hamilton y un puntaje no inferior a 4 en el Test del índice de endogeneidad de Fischer, Fernández Labriola y Rodríguez Casanova. En 57 de ellos se dispuso de perfiles biológicos: Fenil-etilamina, NA y MHPG. Asimismo, en el momento de la admisión ningún paciente estaba ingiriendo antidepresivos. El estudio fue un doble ciego vs. placebo; la edad promedio de los pacientes era de 46 años. El experimento duró 6 semanas. La dosis diaria total se estandardizó en 400mg de toloxatona. Hubo modificaciones significativas en 51 pacietnes. De los 50 casos que recibieron principio activo, 37 obtuvieron un resultado "escelente" o "bueno". Los marcadores biológicos señalaron el perfil de pacientes que mejor responden a la molécula: los de actividad noradrenérgica disminuida. Las depresiones sin ansiedad y las depresiones inhibidas son las patologías de elección para la utilización

Toloxatona y depresión / Toloxatone and depression

Los autores informan la experiencia recogida con la utilización, en 101 pacientes deprimidos, de un antidepressivo de segunda generación, la toloxatona: molécula original dotada de una actividad inhibidora específica y reversible de la MAO A. Al momento de la admisión, los 101 pacientes con enfermedad depresiva presentaban un score mínimo de 20 puntos en al Escala de Hamilton y un puntaje no inferior a 4 en el Test del índice de endogeneidad de Fischer, Fernández Labriola y Rodríguez Casanova. En 57 de ellos se dispuso de perfiles biológicos: Fenil-etilamina, NA y MHPG. Asimismo, en el momento de la admisión ningún paciente estaba ingiriendo antidepresivos. El estudio fue un doble ciego vs. placebo; la edad promedio de los pacientes era de 46 años. El experimento duró 6 semanas. La dosis diaria total se estandardizó en 400mg de toloxatona. Hubo modificaciones significativas en 51 pacietnes. De los 50 casos que recibieron principio activo, 37 obtuvieron un resultado "escelente" o "bueno". Los marcadores biológicos señalaron el perfil de pacientes que mejor responden a la molécula: los de actividad noradrenérgica disminuida. Las depresiones sin ansiedad y las depresiones inhibidas son las patologías de elección para la utilización (AU)