398 research outputs found
Epidermal growth factor receptor (EGFR) downstream signalling pathway in primary colorectal tumours and related metastatic sites: optimising EGFR-targeted treatment options
We analysed the expression of activated (phosphorylated) Akt and MAPK in 98 cases of paired primary colorectal tumours and metastases with the aim to define better the epidermal growth factor receptor (EGFR)-related molecular profile of colorectal cancer as a tool for treatment selection. Among 47 (48%) EGFR-negative primary tumours, 35 cases (74%) were positive for phosphorylated Akt and MAPK. Among 51 (52%) EGFR-positive primary colorectal cancers, 13 (25%) cases were negative for phosphorylated Akt and 15 (29%) were negative for phosphorylated MAPK. In EGFR-negative metastases (56 cases, 55%), phosphorylated Akt was expressed in 41 (73%) and phosphorylated MAPK was expressed in 36 (64%) samples, whereas in EGFR-positive metastases, phosphorylated Akt and MAPK were negative in 14 (31%) and in 10 (22%) cases, respectively. Phosphorylated Akt expression in primary colorectal tumours changed from positive to negative in 16 (16%) paired metastases and from negative to positive in 13 (13%) related metastatic sites. Phosphorylated MAPK expression in primary tumours changed from positive to negative in 13 (13%) paired metastases and from negative to positive in 12 (12%) related metastatic sites. Our findings suggest that phosphorylated Akt and MAPK status in primary tumours does not correlate with Akt and MAPK status in corresponding metastases. EGFR downstream signalling pathway can be overactivated even in the absence of EGFR expression in a considerable proportion of patients
PlGFMMP9-engineered iPS cells supported on a PEGfibrinogen hydrogel scaffold possess an enhanced capacity to repair damaged myocardium
Cell-based regenerative therapies are significantly improved by engineering allografts to express factors that increase vascularization and engraftment, such as placental growth factor (PlGF) and matrix metalloproteinase 9 (MMP9). Moreover, the seeding of therapeutic cells onto a suitable scaffold is of utmost importance for tissue regeneration. On these premises, we sought to assess the reparative potential of induced pluripotent stem (iPS) cells bioengineered to secrete PlGF or MMP9 and delivered to infarcted myocardium upon a poly(ethylene glycol)-fibrinogen scaffold. When assessing optimal stiffness of the PEG-fibrinogen (PF) scaffold, we found that the appearance of contracting cells after cardiogenic induction was accelerated on the support designed with an intermediate stiffness. Revascularization and hemodynamic parameters of infarcted mouse heart were significantly improved by injection into the infarct of this optimized PF scaffold seeded with both MiPS (iPS cells engineered to secrete MMP9) and PiPS (iPS cells engineered to secrete PlGF) cells as compared with nonengineered cells or PF alone. Importantly, allograft-derived cells and host myocardium were functionally integrated. Therefore, survival and integration of allografts in the ischemic heart can be significantly improved with the use of therapeutic cells bioengineered to secrete MMP9 and PlGF and encapsulated within an injectable PF hydrogel having an optimized stiffness
Cancer stem cell gene profile as predictor of relapse in high risk stage II and stage III, radically resected colon cancer patients.
Clinical data indicate that prognostic stratification of radically resected colorectal cancer based on disease stage only may not be always be adequate. Preclinical findings suggest that cancer stem cells may influence the biological behaviour of colorectal cancer independently from stage: objective of the study was to assess whether a panel of stemness markers were correlated with clinical outcome in resected stage II and III colon cancer patients. A panel of 66 markers of stemness were analysed and thus patients were divided into two groups (A and B) with most patients clustering in a manner consistent with different time to relapse by using a statistical algorithm. A total of 62 patients were analysed. Thirty-six (58%) relapsed during the follow-up period (range 1.63-86.5 months). Twelve (19%) and 50 (81%) patients were allocated into group A and B, respectively. A significantly different median relapse-free survival was observed between the 2 groups (22.18 vs 42.85 months, p=0.0296). Among of all genes tested, those with the higher "weight" in determining different prognosis were CD44, ALCAM, DTX2, HSPA9, CCNA2, PDX1, MYST1, COL1A1 and ABCG2. This analysis supports the idea that, other than stage, biological variables, such as expression levels of colon cancer stem cell genes, may be relevant in determining an increased risk of relapse in resected colorectal cancer patient
Role of vascular endothelial growth factor (VEGF) and VEGF-R genotyping in guiding the metastatic process in pT4a resected gastric cancer patients.
In radically resected gastric cancer the possibility to predict the site of relapse could be clinically relevant for the selection of post-surgical management. We previously showed that specific tumour integrins genotypes are independently associated with either peritoneal or hematogenous metastases (ITGA and ITGV). Recently VEGF and VEGF-R polymorphisms have been demonstrated to potentially affect tumour angiogenesis and the metastatic process in gastric cancer. We then investigated the role of VEGFs and VEGF-R genotyping in determining either peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer patients. Tumour genotyping for integrins (ITGA and ITGV) was also performed according to our previous findings. Genotyping for VEGF-A, VEGF-C, VEGFR-1,2,3 and ITGA and ITGV was carried out on pT4a radically resected gastric tumours recurring with either peritoneal-only carcinosis or hematogenous metastases. 101 patients fulfilled the inclusion criteria: 57 with peritoneal carcinomatosis only and 44 with hematogenous spread only. At multivariate analysis, intestinal histology and the AC genotype of rs699947 (VEGFA) showed to independently correlate with hematogenous metastases (p = 0.0008 and 0.008 respectively), whereas diffuse histology and the AA genotype of rs2269772 (ITGA) independently correlated with peritoneal-only diffusion (p = <0.0001 and 0.03 respectively). Our results seem to indicate that combining information from genotyping of rs699947 (VEGFA, AC), rs2269772 (ITGA, AA) and tumour histology could allow clinicians to individuate gastric cancer at high risk for recurrence either with peritoneal or hematogenous metastases. The selection tool deriving from this analysis may allow an optimal use of the available treatment strategies in these patients
Bone marrow cells differentiate in cardiac cell lineages after infarction independently of cell fusion.
Activation of cardiac progenitor cells reverses the failing heart senescent phenotype and prolongs lifespan.
Post-natal cardiomyocytes can generate iPS cells with an enhanced capacity toward cardiomyogenic re-differentation
Adult mammalian cells can be reprogrammed to a pluripotent state by forcing the expression of a few embryonic transcription factors. The resulting induced pluripotent stem (iPS) cells can differentiate into cells of all three germ layers. It is well known that post-natal cardiomyocytes (CMs) lack the capacity to proliferate. Here, we report that neonatal CMs can be reprogrammed to generate iPS cells that express embryonic-specific markers and feature gene-expression profiles similar to those of mouse embryonic stem (mES) cell and cardiac fibroblast (CF)-derived iPS cell populations. CM-derived iPS cells are able to generate chimeric mice and, moreover, re-differentiate toward CMs more efficiently then either CF-derived iPS cells or mES cells. The increased differentiation capacity is possibly related to CM-derived iPS cells retaining an epigenetic memory of the phenotype of their founder cell. CM-derived iPS cells may thus lead to new information on differentiation processes underlying cardiac differentiation and proliferation
Cardiac stem cells possess growth factor-receptor systems that after activation regenerate the infarcted myocardium, improving ventricular function and long-term survival.
Cardiac stem cells and early committed cells (CSCs-ECCs) express c-Met and insulin-like growth factor-1
(IGF-1) receptors and synthesize and secrete the corresponding ligands, hepatocyte growth factor (HGF) and IGF-1.
HGF mobilizes CSCs-ECCs and IGF-1 promotes their survival and proliferation. Therefore, HGF and IGF-1 were
injected in the hearts of infarcted mice to favor, respectively, the translocation of CSCs-ECCs from the surrounding
myocardium to the dead tissue and the viability and growth of these cells within the damaged area. To facilitate
migration and homing of CSCs-ECCs to the infarct, a growth factor gradient was introduced between the site of storage
of primitive cells in the atria and the region bordering the infarct. The newly-formed myocardium contained arterioles,
capillaries, and functionally competent myocytes that with time increased in size, improving ventricular performance at
healing and long thereafter. The volume of regenerated myocytes was 2200 m3 at 16 days after treatment and reached
5100 m3 at 4 months. In this interval, nearly 20% of myocytes reached the adult phenotype, varying in size from 10 000
to 20 000 m3. Moreover, there were 4313 arterioles and 15548 capillaries/mm2 myocardium at 16 days, and 316
arterioles and 39056 capillaries at 4 months. Myocardial regeneration induced increased survival and rescued animals
with infarcts that were up to 86% of the ventricle, which are commonly fatal. In conclusion, the heart has an endogenous
reserve of CSCs-ECCs that can be activated to reconstitute dead myocardium and recover cardiac function
In vitro epigenetic reprogramming of human cardiac mesenchymal stromal cells into functionally competent cardiovascular precursors
Adult human cardiac mesenchymal-like stromal cells (CStC) represent a relatively accessible cell type useful for therapy. In this light, their conversion into cardiovascular precursors represents a potential successful strategy for cardiac repair. The aim of the present work was to reprogram CStC into functionally competent cardiovascular precursors using epigenetically active small molecules. CStC were exposed to low serum (5% FBS) in the presence of 5 \ub5M all-trans Retinoic Acid (ATRA), 5 \ub5M Phenyl Butyrate (PB), and 200 \ub5M diethylenetriamine/nitric oxide (DETA/NO), to create a novel epigenetically active cocktail (EpiC). Upon treatment the expression of markers typical of cardiac resident stem cells such as c-Kit and MDR-1 were up-regulated, together with the expression of a number of cardiovascular-associated genes including KDR, GATA6, Nkx2.5, GATA4, HCN4, NaV1.5, and \u3b1-MHC. In addition, profiling analysis revealed that a significant number of microRNA involved in cardiomyocyte biology and cell differentiation/proliferation, including miR 133a, 210 and 34a, were up-regulated. Remarkably, almost 45% of EpiC-treated cells exhibited a TTX-sensitive sodium current and, to a lower extent in a few cells, also the pacemaker I(f) current. Mechanistically, the exposure to EpiC treatment introduced global histone modifications, characterized by increased levels of H3K4Me3 and H4K16Ac, as well as reduced H4K20Me3 and H3s10P, a pattern compatible with reduced proliferation and chromatin relaxation. Consistently, ChIP experiments performed with H3K4me3 or H3s10P histone modifications revealed the presence of a specific EpiC-dependent pattern in c-Kit, MDR-1, and Nkx2.5 promoter regions, possibly contributing to their modified expression. Taken together, these data indicate that CStC may be epigenetically reprogrammed to acquire molecular and biological properties associated with competent cardiovascular precursors
Drivers of population structure of the bottlenose dolphin (Tursiops truncatus) in the Eastern Mediterranean Sea
The drivers of population differentiation in oceanic high dispersal organisms, have been crucial for research in evolutionary biology. Adaptation to different environments is commonly invoked as a driver of differentiation in the oceans, in alternative to geographic isolation. In this study, we investigate the population structure and phylogeography of the bottlenose dolphin (Tursiops truncatus) in the Mediterranean Sea, using microsatellite loci and the entire mtDNA control region. By further comparing the Mediterranean populations with the well described Atlantic populations, we addressed the following hypotheses: (1) bottlenose dolphins show population structure within the environmentally complex Eastern Mediterranean Sea; (2) population structure was gained locally or otherwise results from chance distribution of preexisting genetic structure; (3) strong demographic variations within the Mediterranean basin have affected genetic variation sufficiently to bias detected patterns of population structure. Our results suggest that bottlenose dolphin exhibits population structures that correspond well to the main Mediterranean oceanographic basins. Furthermore, we found evidence for fine scale population division within the Adriatic and the Levantine seas. We further describe for the first time, a distinction between populations inhabiting pelagic and coastal regions within the Mediterranean. Phylogeographic analysis suggests that current genetic structure, results mostly from stochastic distribution of Atlantic genetic variation, during a recent postglacial expansion. Comparison with Atlantic mtDNA haplotypes, further suggest the existence of a metapopulation across North Atlantic/Mediterranean, with pelagic regions acting as source for coastal environments
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