EGF receptor signaling enhances in vivo invasiveness of DU-145 human prostate carcinoma cells

Carcinomas of the prostate and other lineages often present an autocrine stimulatory loop acting via the EGF receptor (EGFR). We have recently shown that EGFR-mediated signals enhance DU-145 prostate carcinoma cell transmigration of an extracellular matrix in vitro, and that this increased invasiveness was independent of proteolytic degradation of the matrix (Xie et al., 1995, Clin Exp Metastasis, 13, 407). To determine whether up-regulated EGFR signaling promotes tumor progression in vivo and to define the EGFR-induced cell property responsible, we inoculated athymic mice with genetically-engineered DU-145 cells. Parental DU-145 cells and those transduced to overexpress a full-length wild type (WT) EGFR formed tumors and metastasized to the lung when inoculated in the prostate and peritoneal cavity. The WT DU-145 tumors were more invasive. DU-145 cells expressing a mitogenically-active, but motility-deficient (c'973) EGFR formed small, non-invasive tumors without evidence of metastasis. All three sublines demonstrated identical, EGFR-dependent rates of cell growth in vitro, suggesting that the differential invasiveness was not due to altered growth rates. To determine whether cell motility may be, in part, responsible for tumor invasiveness, we treated WT DU-145 intraperitoneal tumors with a pharmacologic agent (U73122) which blocks EGFR-mediated cell motility but not mitogenesis. Under this treatment regimen, the WT DU-145 cells formed tumors of similar numbers and size to those formed without treatment; however, these tumors were much less invasive. These data suggest that EGFR-mediated cell motility is an important mechanism involved in tumor progression, and that this cell property may represent a novel target to limit the spread of tumors.     

Intraglomerular expressions of IL-1 alpha and platelet-derived growth factor (PDGF-B) mRNA in experimental immune complex-mediated glomerulonephritis.

Acute lung injury frequently develops following haemorrhage, and is characterized by increased proinflammatory cytokine levels and massive neutrophil accumulation in the lung. Blood loss produces rapid increases in tumour necrosis factor-alpha (TNF-alpha) mRNA expression among pulmonary cell populations which precede the development of lung injury. In order to examine the role of TNF-alpha in producing acute inflammatory lung injury, we treated mice following haemorrhage and resuscitation with a TNF antagonist, composed of soluble dimeric human p80 TNF receptor linked to the Fc region of human IgG1 (sTNFR:Fc). Therapy with sTNFR:Fc prevented the post-haemorrhage increases in circulating and pulmonary TNF-alpha levels normally found following blood loss. Administration of sTNFR:Fc also diminished the increase in IL-1 beta, IL-6, TNF-alpha and interferon-gamma (IFN-gamma) mRNA normally found in the lungs following haemorrhage. However, therapy with sTNFR:Fc was not associated with improvement in the histologic parameters of post-haemorrhage lung injury, such as neutrophil infiltration and interstitial oedema. In contrast to the effects of sTNFR:Fc on cytokine mRNA levels among intraparenchymal pulmonary mononuclear cells, such therapy following haemorrhage was associated with increased amounts of mRNA for TNF-alpha among peripheral blood mononuclear cells, as well as increased IFN-gamma titres in serum and bronchoalveolar lavage (BAL) specimens. These results indicate that therapy with sTNFR:Fc in the post-haemorrhage period, although capable of decreasing proinflammatory cytokine expression in the lungs, does not prevent the development of acute lung injury in this setting.     

Interactions between normal and tumoral tissues at the boundary of human anterior pituitary adenomas

We studied the boundary between adenoma and peritumoral anterior pituitary tissues in order to understand their mutual interactions during tumour progression. We selected 18 adenomas of different secretory type, grade and invasiveness in which fragments of peritumoral anterior pituitary were still attached to the adenoma. Immunohistochemistry was performed on serial sections with markers of the basement membranes (type IV collagen), the hormone-producing cells of the normal and neoplastic anterior pituitary, and the folliculo-stellate cells (S-100 protein). In passing from tumour to gland, localized areas of passive compression of the normal gland were seen in only 3 cases. In all the tumours, the boundary consisted partly or solely of a transitional zone characterized by the presence of enlarged cell-cords. Openings in the basement membrane of these enlarged cell-cords were seen in contact with the tumour tissue. Normal and neoplastic cells intermingled in the transitional zone. Normal residual cells could be seen in the central area of the tumour but no adenomatous cells were observed in the gland around the tumour. Folliculo-stellate cells were concentrated in the vicinity of the transition zone. These findings favour the existence of an active process of adenoma expansion within the normal parenchyma, without noticeable infiltration of tumour cells into surrounding gland.     

Evaluation of the Interaction Between TGF <Emphasis Type="Italic">β</Emphasis> and Nitric Oxide in the Mechanisms of Progression of Colon Carcinoma

It is recognised that stromal cells determine cancer progression. We have previously shown that active TGFβ produced by rat colon carcinoma cells modulated NO production in rat endothelial cells. To elucidate the role of TGFβ and NO in the mechanisms of interaction of colon carcinoma cells with stromal cells and in cancer progression, we transfected REGb cells, a regressive colon carcinoma clone secreting latent TGFβ, with a cDNA encoding for a constitutively-secreted active TGFβ. Out of 20 injected rats only one tumour progressed, which was resected and sub-cultured (ReBeta cells). ReBeta cells secreted high levels of active TGFβ. The adhesive properties of REGb and Rebeta cells to endothelial cells were similar, showing that the secretion of active TGFβ is not involved in tumour cell adhesion to endothelial cells. ReBeta, but not REGb, cell culture supernatants inhibited cytokine-dependent NO secretion by endothelial cells, but inhibition of NO production was similar in co-cultures of REGb or ReBeta cells with endothelial cells. Therefore, secretion of active TGFβ regulated endothelial NO synthase activity when tumour cells were distant from, but not in direct contact with, endothelial cells. However, only ReBeta cells inhibited cytokine-dependent secretion of NO in coculture with macrophages, indicating that the active-TGFβ–NO axis confers an advantage for tumour cells in their interaction with macrophages rather than endothelial cells in cancer progression.     

CD8+T-bet+ cells as a predominant biomarker for inclusion body myositis

Background

Myositis is a heterogeneous group of muscular auto-immune diseases with clinical and pathological criteria that allow the classification of patients into different sub-groups. Inclusion body myositis is the most frequent myositis above fifty years of age. Diagnosing inclusion body myositis requires expertise and is challenging. Little is known concerning the pathogenic mechanisms of this disease in which conventional suppressive-immune therapies are inefficacious.

Functional variation of HIV-1 Rev Response Element in a longitudinally studied cohort

We showed previously that HIV-1 Rev Response Element (RRE) contains a certain degree of structural variation, and in a set of limited samples, RRE from HIV-1 natural isolates were found to have functional variability. The significance of the RRE heterogeneity is addressed further by analyzing the functional variation of RREs in a longitudinal cohort. While the RRE activity at early time points was not a good predictor of disease outcome, the RRE activity at late time points was correlated with rates of CD4+ count decline. These data suggest that RRE heterogeneity may be important in viral pathogenesis and disease progression.     

Expression of c-ets-1 mRNA is associated with an invasive, EMT-derived phenotype in breast carcinoma cell lines

We have previously observed in vitro that some stromal proteinases (MMP-2, MT1-MMP) were expressed or activated by invasive carcinoma cell lines exhibiting mesenchymal features, presumably acquired through an epithelial to mesenchymal transition (EMT). To examine the potential contribution of c-ets-1 to this phenotype, we have compared here the expression of c-ets-1 with invasiveness in vitro and expression of vimentin, E-cadherin, uPA, MMP-1 and MMP-3 in a panel of human breast cancer cell lines. Our results clearly demonstrate an association between c-ets-1 expression and the invasive, EMT-derived phenotype, which is typified by the expression of vimentin and the lack of E-cadherin. While absent from the two non-invasive, vimentin-negative cell lines, c-ets-1 was abundantly expressed in all the four vimentin-positive lines. However, we could not find a clear quantitative or qualitative relationship between the expression of c-ets-1 and the three proteinases known to be regulated by c-ets-1, except that when they were expressed, it was only in the invasive c-ets-1-positive lines. UPA mRNAs were found in three of the four vimentin-positive lines, MMP-1 in two of the four, and MMP-3 could not be detected in any of the cell lines. Intriguingly, MDA-MB-435 cells, which exhibit the highest metastatic potential of these cell lines in nude mice, expressed vimentin and c-ets-1, but lacked expression of these three proteinases, at least under the culture conditions employed. Taken together, our results show that c-ets-1 expression is associated with an invasive, EMT-derived phenotype in breast cancer cells, although it is apparently not sufficient to ensure the expression of uPA, MMP-1 or MMP-3, in the vimentin-positive cells. Such proteases regulation is undoubtedly qualified by the cellular context. This study therefore advances our understanding of the molecular regulation of invasiveness in EMT-associated carcinoma progression, and suggests that c-ets-1 may contribute to the invasive phenotype in carcinoma cells.     

T cell receptor usage in patients with non-progressing HIV infection

It is still unclear why some patients with HIV progress more slowly than others to developing full blown AIDS. In this study using flow cytometry we have investigated the TCRBV repertoire of peripheral blood T lymphocytes in 17 long-term non-progressing HIV patients (LTNP) to determine if there is a biased usage of T cell receptor V gene products. Patients were identified from hospital records and entered into the study. Three colour flow cytometry was used to determine the expression of the TCRBV3S5, BV5S1, BV5S2, BV5S3, BV6S1, BV7S1, BV9, BV11, BV12, BV13, BV14, BV16, BV17, BV18, BV20, BV21S3, BV22, and BV23 by CD8 and CD4 positive cells isolated from the peripheral blood of patients and controls. Increases in the absolute numbers of CD8+ T cells expressing TCRBV2 and 8 were observed in the HIV-LTNP population (P < 0.05 in both cases). No differences were seen in numbers of CD8+ T cells expressing other TCRBV or in any TCRBV within the CD4+ T cell popu-lation. At follow up (1-2 years later), those patients in which CD4 levels were below 500 x 106/l were those initially found to have lower levels of TCRBV8 +ve CD8 cells. A significant increase in the absolute numbers of T cells coexpressing the gamma delta (gammadelta) T cell receptor and CD8 were also seen in the HIV-LTNP patients compared with controls (P = 0.002). The increase in CD8+ T cells in the HIV-LTNP patients may be interpreted as either an antigen specific, or group of antigen specific responses to viral antigen, or less likely a viral superantigen. A low level of TCRBV8, CD8+ T cells might be predictive of a more rapid disease progression and might indicate a protective role for this population in HIV infected patients. The increase in gammadeltaT cells bearing the CD8 coreceptor suggests a role for this cell type in the response to HIV infection.