摘要:

Autotaxin is a 125kD autocrine motility factor that stimulates both random and directed motility in producing the human A2058 melanoma cell line. The recently cloned autotaxin has been demonstrated to bind strongly and specifically to concanavalin A (con A). In this study, we show that the oligosaccharide side chains on autotaxin are exclusively asparagine linked, since W-glycosidase F, but not neuraminidase or O-glycosidase, decreases the protein molecular mass to 100–105kD, which is the calculated molecular mass of the deduced autotaxin polypeptide. Furthermore, removal of oligosaccharide side chains by W-glycosidase F can be performed under mild conditions that retain motility-stimulating activity, suggesting that the oligosaccharide side chains are not necessary for autotaxin to activate its receptor. Finally, when melanoma cells are treated with inhibitors of carbohydrate processing, such as /V-methyl-1-deoxy-nojirimycin, 1-deoxymannojirimycin and swainsonine, they still secrete a motility-stimulating autotaxin. Therefore, the carbohydrate side chains on autotaxin are not necessary to stimulate motility; however, they may still play a role in folding, secretion or maintenance of the active conformation of the protein.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Recently, fluorescence spectroscopy and imaging have been under investigation forin vivodiagnosis of several types of superficial cancer, including primary melanomas of the skin. Here we report on a detailed investigation of the autofluorescence properties of a K1735P melanoma implanted intradermal⁁ in the ears of syngeneic C3H/HeN mice. Although this tumour can produce melanin in some cases, it appeared as an unpigmented lesion in our experiments. Excitation-emission maps in the wavelength range of 360–700 nm were recorded from tumours and normal ears. The control ears and the tumour-bearing ears showed fluorescence in a broad range of excitation and emission wavelengths. Valleys of decreased fluorescence were observed in the 385–425 nm range and could be related to absorption of the excitation light by haemoglobin, oxyhaemoglobin and a third unknown absorber. The spectroscopic differences between the malignant melanoma and the control skin could be related to either differences in blood oxygenation or the tissue dimensions. However, no spectroscopic features were detected reflecting intrinsic differences between the melanoma and normal tissue.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

LM mouse fibroblasts (H-2k) were modified for the expression of (antibody-defined) melanoma-associated antigens (MAA) and the secretion of interleukin-2 (IL-2) and interferon-gamma (IFN-γ) (RLBA-IL-2/IFN-γ cells). The cell construct was tested for its immunogenic properties in C57BL/6 mice (H-2b) with B16 melanoma. The results indicated that the survival of mice injected with a mixture of B16 cells and the modified, double cytokine-secreting fibroblasts was significantly longer than that of mice injected with B16 cells and LM cells modified for the expression of MAA and the secretion of IL-2 or IFN-γ alone (RLBA-IL-2 or RLBA-IFN-γ cells). Both natural killer/ lymphokine-activated killer (NK/LAK) cells and Lyt-2.2+CTLs with anti-melanoma cytotoxic activities were predominant in mice immunized with the double cytokine-secreting cells. B16 melanoma cells persisted in mice treated with RLBA-IL-2 cells (B16-R3). The B16-R3 cells were resistant to anti-melanoma effector cells from mice immunized with RLBA-IL-2 cells. The recurrent melanoma cells were deficient in the expression of MHC class I determinants. Class I expression by B16-R3 cells was increased if they were incubated in medium conditioned by the growth of IFN-γ-secreting RLBA-IL-2/IFN-γ or RLBA-IFN-Y cells. After incubation, the sensitivity of B16-R3 melanoma cells to immune-effector cells from mice immunized with RLBA-IL-2 cells was restored. The survival of mice bearing low MHC class l-expressing B16-R3 cells, treated RLBA-IL-2/IFN-γ cells, was determined. The treated animals survived significantly longer than mice with B16-R3 melanoma treated with RLBA-IL-2 cells. Similar results were obtained for mice with B16-R3 melanoma treated with RLBA-IFN-γ cells. We postulate that immunization of mice with IL-2/IFN-γ double cytokine-secreting cells stimulated multiple anti-melanoma effector mechanisms. Analogous to the enhanced therapeutic antitumour effects of combination chemotherapy, it was likely that treatment with a cellular immunogen engineered to stimulate more than one effector mechanism resulted in the elimination of larger numbers of tumour cells than treatment with an immunogen that stimulated a single effector mechanism alone.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Human melanoma cells have been used to evaluate whether stepdown heating (SDH) could increase the effectiveness of long-duration mild hyperthermia (LDMH). The effects of these treatments were also evaluated on cell survival and DNA polymerase inactivation. Short treatments (30 min) at 43°C did not result in much SDH effect for subsequent protracted heating at 40°C. The effect on DNA polymerases was also very small. However, heating at 44°C for 30 min had a large SDH heating effect on subsequent heating at 40°C and 41°C. The SDH effect occurred mainly in the first 5–10 h of subsequent LDMH and, at longer heating times, the rate of cell killing was reduced. The 44°C SDH effect was also observed on DNA polymerase inactivation. Comparing the degree of cell killing and polymerase inactivation showed a good correlation for the various SDH protocols.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Adhesion molecules are likely to play a role in the process of tumour progression. We investigated the expression of integrins, ICAM-1, and CD44 and the influence of interferon-alpha (IFN-a), interferon-gamma (IFN-γ), and tumour necrosis factor-alpha (TNF-α) on expression of these molecules on four uveal melanoma cell lines. Thein vitrointegrin expression was quite variable. The αV and β1 subunits were expressed on all cell lines, and none of the cell lines showed any α3, β2, or β4 expression. Other integrin subunits showed a more variable pattern. ICAM-1 and CD44 were strongly expressed on all cell lines. IFN-α, IFN-γ, and TNF-α upregulated Zα1, α2, and α3 expression, and did not alter α4, α5, α6, β2, αvβ3, and β4 expression. The effects on αV and αβ5 were variable. ICAM-1 was upregulated by IFN-γ and TNF-α, but not by IFN-α. Cytokine treatment hardly changed CD44 expression. In one case a comparison was made between expression on cultured cells and on tissue sections of the tumour of origin. Differences in expression were observed for the integrin subunits a2, a3, and a5. This study shows that integrins and ICAM-1 expression on uveal melanoma cellsin vitroare susceptible to cytokine treatment, but that the effects on integrin expression are cytokine and cell line dependent. Furthermore, some differences in integrin expression between cellsin vivoandin vitroexist.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

TheWAF1gene, located on chromosome 6p, encodes aMr21 000 protein (p21) that can arrest cell growth by associating with and inhibiting cyclin-dependent kinase complexes that are necessary for cells to exit Gr. Transcriptional activation ofWAF1can be accomplished by increasing levels of p53 protein induced by various cellular stresses, including DNA damage. Metastatic melanomas are paradoxical in that most overexpress wild-type p53 protein, yet cell growth is not inhibited. Thus, it is possible that lack of growth suppression in melanomas is due, in part, to mutations in theWAF1gene. Therefore, we examined the entire coding region of theWAF1gene in 24 metastatic melanoma cell lines and three normal melanocyte lines by single-strand conformation polymorphism (SSCP) analysis and direct DNA sequencing. We similarly examined the DNA from lymphoblastoid cell lines, derived from nine individuals belonging to seven melanoma-prone families, in which haplotypes of markers on 6p co-segregate with melanoma for germline mutations in theWAF1gene. Results indicate that (i) mutation of theWAF1gene is an infrequent event in individuals with sporadic melanoma or predisposed to familial melanoma and (ii) the uncontrolled growth of melanoma cells is not due to mutation of theWAF1gene. However, expression studies found a wide variation in the level of p21 protein in melanoma cells, suggesting that aberrant regulation of p21 may play a role in melanoma development. Moreover, there was no predictable relationship between p21 expression and p53 expression, indicating that other, p53-independent, pathways may be important for the regulation of p21 in melanoma cells.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Studies on cytogenetic abnormalities and cell lines have implicated chromosome 1p32 as being important in the pathogenesis of melanoma. Genetic linkage studies have also mapped a melanoma-susceptibility locus to chromosome 1p. The geneTAL1is present on chromosome 1 p32, and deletions within it are the commonest chromosomal abnormality in T-acute lymphoblastic leukaemia (T-ALL). A melanoma cell line harbouring a 1p32 deletion involving theTAL1gene and the presence of TAL1 protein in developing mouse melanocytes led us to investigate whether TAL1 deletions and/or TAL1 protein expression occur in sporadic melanomas. DNA extracted from 32 fresh melanomas was amplified by standard polymerase chain reaction for the four common deletions of theTAL1gene that occur in T-ALL. In addition, frozen and paraffin-embedded sections of these melanomas were stained with monoclonal antibodies that detect full-length and truncated TAL1 protein. The results of the study show that deletions ofTAL 1do not occur in melanoma. Indeed, full and truncated TAL1 protein also could not be detected immunohistochemically in the paraffin-embedded and frozen sections of the melanomas. We conclude that theTAL1gene and its protein are probably not directly involved in the oncogenesis of melanomas.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The value of elective lymph node dissection (ELND) for melanoma patients with clinically uninvolved regional nodes remains controversial. However, it has been proposed that selective 'sentinel' lymph node biopsy reliably identifies individuals with micrometastases, who are most likely to benefit from full ELND. The aim of this study was to confirm that metastatic melanoma cells travelling in lymphatics do not bypass the sentinel node. After preoperative lymphoscintigraphy and intraoperative injection of blue dye around the primary melanoma site, sentinel node biopsy was performed in 118 melanoma patients for whom full ELND was planned as part of their definitive surgical treatment. A confidently identified sentinel node was tumour positive in 22 out of 105 regional lymph node fields (21%). In 18 cases the sentinel node was the only node found to be involved and in four cases, additional nodes were positive. In two other patients a positive node was found when the sentinel lymph node had been negative. However, in each case an avoidable error of technique had occurred and definite blue staining indicated that the positive node was in fact another sentinel node. This study thus confirms that sentinel lymph node status reliably indicates whether metastatic melanoma is present in regional lymph nodes.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Sinonasal melanoma is a rare malignancy. We present the clinicopathologic review of 18 cases seen at the British Columbia Cancer Agency between 1976 and 1992: 13 men and five women, mean age 66 years (range 32–88). Patients presented with nasal obstruction and bleeding (n= 8), obstruction alone (n= 4), bleeding alone (n= 5) or pain (n= 1). Those with bleeding presented with a shorter duration of symptoms than those with obstruction alone. All patients with obstruction alone died of their disease, while all patients with bleeding alone are alive or have died of an unrelated cause; four out of eight patients with both obstruction and bleeding are alive. There was no significant relationship between treatment modality and outcome. Histologic subtypes included epithelioid (n= 10), spindle-cell (n= 4), small-cell (n= 3) and pleomorphic (n= 1). Eight out of 11 cases from whom samples of paraffin-embedded tissue were available showed more prominent staining for HMB-45 than for S-100. In two cases, only rare (<0.1%) cells stained for S-100. Cell type, mitotic rate and P53 expression were unrelated to disease outcome. Six out of seven patients with ≤10% of cells showing intense staining for PCNA were alive or had died of an unrelated cause, while three out of four with >10% staining died of their disease. These data suggest that presentation with bleeding and a low degree of staining for PCNA may be favourable prognostic factors in sinonasal melanoma, and that HMB-45 may be a more sensitive marker than S-100 for melanocyte differentiation in sinonasal neoplasms.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The histological and immunocytochemical appearances of skin with altered pigmentation from two patients receiving chemoimmunotherapy for melanoma were examined. In both patients, there was a clinical response to treatment coincident with depigmentation of skin and hair. Skin biopsies showed extensive infiltration with CD8 +and CD4+ lymphocytes rather than CD57+ in the depigmented areas suggestive of a specific MHC-related cytotoxic T-cell activity against melanocytes. In keeping with this, MHCII expression was markedly up-regulated. These observations suggest the development of a simultaneous anti-tumour and anti-melanocyte immune response stimulated by chemoimmunotherapy, possibly against the same or similar antigens.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID