Growth on poly(L-lactic acid) porous scaffold preserves CD73 and CD90 immunophenotype markers of rat bone marrow mesenchymal stromal cells.

Few data are available on the effect of biomaterials on surface antigens of mammalian bone marrow-derived, adult mesenchymal stromal cells (MSCs). Since poly(L-lactic acid) or PLLA is largely used in tissue engineering of human bones, and we are developing a reverse engineering program to prototype with biomaterials the vascular architecture of bones for their bioartificial reconstruction, both in humans and animal models, we have studied the effect of porous, flat and smooth PLLA scaffolds on the immunophenotype of in vitro grown, rat MSCs in the absence of any coating, co-polymeric enrichment, and differentiation stimuli. Similar to controls on plastic, we show that our PLLA scaffold does not modify the distribution of some surface markers in rat MSCs. In particular, the maintained expression of CD73 and CD90 on two different subpopulations (small and large cells) is consistent with their adhesion to the PLLA scaffold through specialized appendages, and to their prominent content in actin. In addition, our PLLA scaffold favours retention of the intermediate filament desmin, believed a putative marker of undifferentiated state. Finally, it preserves all rat MSCs morphotypes, and allows for their survival, adhesion to the substrate, and replication. Remarkably, a subpopulation of rat MSCs grown on our PLLA scaffold exhibited formation of membrane protrusions of uncertain significance, although in a size range and morphology compatible with either motility blebs or shedding vesicles. In summary, our PLLA scaffold has no detrimental effect on a number of features of rat MSCs, primarily the expression of CD73 and CD90.

Expression of collagen VI α5 and α6 chains in human muscle and in Duchenne muscular dystrophy-related muscle fibrosis.

Collagen VI is a major extracellular matrix (ECM) protein with a critical role in maintaining skeletal muscle functional integrity. Mutations in COL6A1, COL6A2 and COL6A3 genes cause Ullrich Congenital Muscular Dystrophy (UCMD), Bethlem Myopathy, and Myosclerosis. Moreover, Col6a1(-/-) mice and collagen VI deficient zebrafish display a myopathic phenotype. Recently, two additional collagen VI chains were identified in humans, the α5 and α6 chains, however their distribution patterns and functions in human skeletal muscle have not been thoroughly investigated yet. By means of immunofluorescence analysis, the α6 chain was detected in the endomysium and perimysium, while the α5 chain labeling was restricted to the myotendinous junctions. In normal muscle cultures, the α6 chain was present in traces in the ECM, while the α5 chain was not detected. In the absence of ascorbic acid, the α6 chain was mainly accumulated into the cytoplasm of a sub-set of desmin negative cells, likely of interstitial origin, which can be considered myofibroblasts as they expressed α-smooth muscle actin. TGF-ß1 treatment, a pro-fibrotic factor which induces trans-differentiation of fibroblasts into myofibroblasts, increased the α6 chain deposition in the extracellular matrix after addition of ascorbic acid. In order to define the involvement of the α6 chain in muscle fibrosis we studied biopsies of patients affected by Duchenne Muscular Dystrophy (DMD). We found that the α6 chain was dramatically up-regulated in fibrotic areas where, in contrast, the α5 chain was undetectable. Our results show a restricted and differential distribution of the novel α6 and α5 chains in skeletal muscle when compared to the widely distributed, homologous α3 chain, suggesting that these new chains may play specific roles in specialized ECM structures. While the α5 chain may have a specialized function in tissue areas subjected to tensile stress, the α6 chain appears implicated in ECM remodeling during muscle fibrosis.

Expression of the collagen VI α5 and α6 chains in normal human skin and in skin of patients with collagen VI-related myopathies.

Collagen VI is an extracellular matrix protein with critical roles in maintaining muscle and skin integrity and function. Skin abnormalities, including predisposition to keratosis pilaris and abnormal scarring, were described in Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) patients carrying mutations in COL6A1, COL6A2, and COL6A3 genes, whereas COL6A5, previously designated as COL29A1, was linked to atopic dermatitis. To gain insight into the function of the newly identified collagen VI α5 and α6 chains in human skin, we studied their expression and localization in normal subjects and in genetically characterized UCMD and BM patients. We found that localization of α5, and to a lesser extent α6, is restricted to the papillary dermis, where the protein mainly colocalizes with collagen fibrils. In addition, both chains were found around blood vessels. In UCMD patients with COL6A1 or COL6A2 mutations, immunolabeling for α5 and α6 was often altered, whereas in a UCMD and in a BM patient, each with a COL6A3 mutation, expression of α5 and α6 was apparently unaffected, suggesting that these chains may substitute for α3, forming α1α2α5 or α1α2α6 heterotrimers.

Activated Akt as an indicator of prognosis in gastric cancer.

The immunohistochemical expression of phosphorylated (activated) Akt (pAkt) in 50 advanced gastric carcinomas has been analyzed and the results correlated with age, sex, location in the stomach, histotype, stage, survival, mitotic and apoptotic index, some cell cycle regulators (cyclin D1, cyclin E, p34/cdc2, p27/kip1), and cell proliferation. There was a statistically significant direct correlation between pAkt expression (both cytoplasmatic and nuclear) and depth of infiltration of the tumor, number of infiltrated lymph nodes and p34/cdc2 expression, and between prevalently nuclear pAkt and cyclin D1 and cyclin E. Conversely, there was a significant inverse correlation between nuclear pAkt and apoptotic index and between cytoplasmatic and nuclear pAkt and patient survival. No correlation was found between pAkt and sex, age, tumor location, histotype, mitotic index, and cell proliferation. These findings suggest that pAkt may be considered an indicator of tumor progression and patient survival in gastric cancer.

Cyclosporin A corrects mitochondrial dysfunction and muscle apoptosis in patients with collagen VI myopathies.

Ullrich congenital muscular dystrophy and Bethlem myopathy are skeletal muscle diseases that are due to mutations in the genes encoding collagen VI, an extracellular matrix protein forming a microfibrillar network that is particularly prominent in the endomysium of skeletal muscle. Myoblasts from patients affected by Ullrich congenital muscular dystrophy display functional and ultrastructural mitochondrial alterations and increased apoptosis due to inappropriate opening of the permeability transition pore, a mitochondrial inner membrane channel. These alterations could be normalized by treatment with cyclosporin A, a widely used immunosuppressant that desensitizes the permeability transition pore independently of calcineurin inhibition. Here, we report the results of an open pilot trial with cyclosporin A in five patients with collagen VI myopathies. Before treatment, all patients displayed mitochondrial dysfunction and increased frequency of apoptosis, as determined in muscle biopsies. Both of these pathologic signs were largely normalized after 1 month of oral cyclosporin A administration, which also increased muscle regeneration. These findings demonstrate that collagen VI myopathies can be effectively treated with drugs acting on the pathogenic mechanism downstream of the genetic lesion, and they represent an important proof of principle for the potential therapy of genetic diseases.

Expression of cell cycle-regulated proteins pRB2/p130, p107, E2F4, p27, and pCNA in salivary gland tumors: prognostic and diagnostic implications.

The retinoblastoma family consists of the tumor suppressor nuclear phosphoprotein pRb/p105 and related proteins p107 and pRb2/p130. Recent immunohistochemical studies of the retinoblastoma family of proteins in lung and endometrial cancer and choroidal melanomas show a tight inverse correlation between the histologic grading in the most aggressive tumor types and pRb2/p130 expression. This led us to investigate the role of pRb2/p130 in salivary tumors. We studied the expression of pRb2/p130, p107, E2F4, p27, and PcNA by immunohistochemistry in a panel of 44 salivary gland tumors. We found a direct correlation between the cytoplasmic expression of pRb2/p130 and tumor grading and the presence of metastasis that was highly statistically significant (P < 0.001). Additionally, increased cytoplasmic pRb2/p130 expression was significantly correlated with a decreased probability of survival (P < 0.001). Interestingly, p107 nuclear expression showed a strong direct correlation when compared with the same variables. pRb2/p130 showed the highest percentage of undetectable nuclear levels in the specimens examined and the tightest inverse correlation (P < 0.0001) with both the histologic grading and pCNA expression in malignant salivary tumors. Additionally, E2F4 showed an identical localization pattern as to that of pRb2/p130. These data suggests an important role for pRb2/p130 in the pathogenesis and progression of certain salivary gland cancers.

Frequent loss of expression of the cyclin-dependent kinase inhibitor p27(Kip1) in estrogen-related Endometrial adenocarcinomas.

PURPOSE: p27(Kip1) is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. Low levels of p27 are associated with poor prognosis in a variety of gynecological tumors, including breast, ovarian, and cervical carcinomas. The role of p27 in endometrial cancer remains controversial. EXPERIMENTAL DESIGN: In the present study, p27 protein expression was investigated by immunohistochemistry in a series of 217 endometrial adenocarcinomas and, where present, in synchronous normal endometrium, simple and complex hyperplasia (with or without atypia), and cystic atrophy. The relationship between p27 expression and clinical outcome was also evaluated. RESULTS: Immunohistochemical analysis revealed a significant loss of p27 expression from normal (33%) through hyperplastic endometrium (50%) to endometrial adenocarcinomas (71%; P

Expression of cell-cycle-regulated proteins pRb2/p130, p107, p27(kip1), p53, mdm-2, and Ki-67 (MIB-1) in prostatic gland adenocarcinoma.

PURPOSE: The quest for prognostic molecular markers in prostatic carcinoma is still in progress. Many proteins have already been screened by immunohistochemistry with the aim to find the most reliable indicator of progressive disease. In this study, we evaluated the expression of pRb2/p130, p107, p27(kip1), p53, mdm-2, and Ki-67 (MIB-1) by immunohistochemistry in 24 prostate carcinomas compared with the paired expression of normal prostates. EXPERIMENTAL DESIGN: Expression of the different proteins in normal and pathological specimens was evaluated by the Wilcoxon test. A matrix of correlation (Spearman coefficient) was used to evaluate the possible association in expression among the different proteins. Logistic regression analysis was used to test the multivariable prognostic value of the levels of protein expression for the probability of disease development. RESULTS: p53 and Ki-67 (MIB-1) showed a higher expression in cancer than in normal tissue (P = 0.006 and <0.001, respectively). pRb2/p130, p107, and p27(kip1) showed an overall lower expression in cancer, but the difference between cytoplasmic and nuclear expression was always higher for cancer (Ps, from <0.001 to 0.016). mdm-2 expression was lower in cancer, but the difference between cytoplasmic and nuclear expression was not significant (P = 0.571) when compared with that in normal tissue. A positive correlation between p27 and pRb2/p130 levels expressed, in normal and cancer counterparts in the same sample, as the difference between cytoplasmic and nuclear protein concentrations (P = 0.045) was found. Additionally, p107 expression showed an inverse correlation with Ki-67 (MIB-1) expression in the most aggressive tumors (P = 0.046). Logistic regression output showed that Ki-67 (MIB-1) and pRb2/p130 (expressed as differences between cytoplasmic and nuclear concentrations) were the variables associated with a higher risk of cancer. The highest value was reported for Ki-67 (MIB-1) (odds ratio, 2.11), followed by pRb2/p130 (odds ratio, 1.01). pRb2/p130 alone was associated with a sensitivity (rate of cases having a posterior probability of disease >/=0.5) of 61% with a false positive rate of 22%. Ki-67 (MIB-1) alone yielded a sensitivity of 69% and a false positive rate of 14%. The combined model (Ki-67 + pRb2/p130) yielded a sensitivity of 83% with a false positive rate of 17%. Interestingly, one specimen in which we also found a high-grade prostatic intraepithelial neoplasia showed the progressive loss of pRb2/p130 from normal prostatic cells to prostatic intraepithelial neoplasia cells, suggesting that in prostatic cancer, lack of expression of the tumor suppressor gene pRb2/p130 could be involved in the progression of the disease, from an early stage. CONCLUSIONS: This study showed that all of the proteins but mdm-2 were expressed at a different rate in normal and pathological prostate specimens. Multivariate analysis showed that pRb2/p130 and p107 may be involved in the pathogenesis and progression of prostate cancers, and that the expression of the retinoblastoma-related protein pRb2/p130 along with Ki-67 (MIB-1), expressed as differences between cytoplasmic and nuclear concentrations, could be considered new parameters to be evaluated in discriminating patients at a higher risk for prostate cancer.