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Biomedical subjects

G Fossati

Publications and source records attributed to G Fossati.

At least 73 records · Page 4Linked to original sources
PubMed1990

Immunocytochemical localization and identification of prosomatostatin gene products in medullary carcinoma of human thyroid gland.

Thirty-three cases of histologically proven calcitonin-positive medullary thyroid carcinoma were studied immunocytochemically for the occurrence of prosomatostatin-related peptides. Positive cells, identified with a panel of antisera raised against four different regions of the prosomatostatin molecule, were found in 100% of the tumors. Most but not all somatostatin-positive cells were also immunoreactive for calcitonin. Notably, seven patients harboring somatostatin-rich tumors revealed a more favorable clinical course. The results (1) indicate that somatostatin production is a universal concomitant of thyroid medullary carcinoma, (2) suggest that these cells are likely to produce a somatostatin precursor molecule similar to mammalian prosomatostatin, and (3) imply that somatostatin-reactive cells may have as yet unknown roles in these tumors, possibly in the realm of paracrine and autocrine regulation of cell growth.

Adolescent↗
PubMed1990

Chromosome abnormalities and fragile sites in human melanoma.

Chromosome analysis in short-term lines of three primary and seven metastatic malignant melanomas showed aneuploid karyotypes with recurrent abnormalities of chromosomes 1 (five cell lines), 6 (nine cell lines), and 7 (six cell lines). The breakpoints observed on the rearranged chromosomes frequently coincided with loci of known oncogenes and fragile sites. Two of the cell lines were analyzed after xenograft into nude mice and showed the presence of the same chromosomal changes observed in the parental cell lines, indicating the stability of the karyotype. A tendency toward an increased chromosomal fragility in peripheral blood lymphocytes was observed in five melanoma patients compared to ten normal individuals. However, there was no increased level of expression of specific fragile sites corresponding to the breakpoints observed in melanoma cells.

Chromosome Aberrations↗
PubMed1989

Loss of heterozygosity of DQ alpha gene in human malignant melanoma.

DNAs from human melanoma cells, used at early in vitro passage, were evaluated by Southern blot analysis for somatic loss of heterozygosity at the DQ alpha gene. A total of 7 melanomas, 3 primary and 4 metastatic derived from 5 different patients were studied; in one case (pt 665) cell lines were derived from two anatomically different subcutaneous metastasis, whereas in a second case (pt 9923) both the primary tumor and a lymph node metastasis were available. Restriction length polymorphism (RFLP) analysis, performed on autologous peripheral blood lymphocyte (PBL) DNA digested with different enzymes, showed a pattern of bands compatible with the constitutional heterozygous typing at DQ alpha gene in 4 cases whereas 1 case revealed an homozygous typing. When melanoma DNAs were analysed, 1 out of the 4 informative cases (pt 1007) showed a loss of a diagnostic fragment for DQ alpha gene when digested with both Taq I and Bgl I enzymes. These results indicate that class II allelic losses detectable by RFLP can be found on malignant melanoma and add further complexity on the involvement of chromosome 6 whose cytogenetic abnormality are the most consistent in this human neoplasia.

DNA, Neoplasm↗
PubMed1989

Cytotoxic T lymphocyte clones from peripheral blood and from tumor site detect intratumor heterogeneity of melanoma cells. Analysis of specificity and mechanisms of interaction.

CTL clones isolated from PBL or from tumor-infiltrating lymphocytes (TIL) of a melanoma patient (pt665) were screened for specificity on a panel including autologous tumor cells from two distinct metastases (Me665/1, Me665/2), autologous EBV-transformed B cells and 15 allogeneic cell lines of different histology. Each clone displayed a peculiar cytolytic activity ranging from lysis of most targets (PBL clone 4C4) to preferential reactivity on the two autologous metastases (TIL clone 8B3). Blocking and modulation experiments, revealed that the lysis of autologous-Tu cells by TIL clone 8B3, but not by PBL clone 4C4, could be inhibited by mAb to HLA-class I and to CD3 Ag or by CD3 complex modulation. Clone 8B3 was tested also on a panel of 25 tumor clones from Me665/2, revealing that only 4 neoplastic clones were lysed (2/4, 2/14, 2/17, and 2/51). Cold target competition experiments indicated that the uncloned autologous melanomas and one tumor clone (2/17), but no two other tumor clones (2/10, 2/15), could compete with one another for lysis by 8B3. Determination of melanin content of tumor clones from Me665/2 revealed that the four neoplastic clones recognized by 8B3 possessed much lower melanin levels than all the other 20 clones not lysed by this effector.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Lysis by interleukin 2-stimulated tumor-infiltrating lymphocytes of autologous and allogeneic tumor target cells.

Peripheral blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) were isolated from six cancer patients and cultured in the presence of 100 units/ml of recombinant interleukin 2 (IL2). Both IL2-stimulated PBL (IL2-PBL) and IL2-stimulated TIL (IL2-TIL) lysed fresh and short-term cultured autologous tumor cells in four and six cases, respectively. In four out of six patients IL2-TIL showed a slightly higher tumor cytotoxicity than IL2-PBL without lysing autologous normal PBL or TIL. Like IL2-PBL, IL2-TIL also killed allogeneic fresh and cultured targets of different histotypes, suggesting a lack of autologous tumor cytotoxic specificity. TIL cultured for 3 weeks in IL2 maintained their killing activity against autologous and allogeneic tumor targets. Phenotypic analysis of uncultured TIL showed a predominance of CD3+ T cells (approximately 70%) with CD4+ (approximately 60%) and CD8+ (20%) lymphocyte subsets, whereas less than or equal to 3% of CD16+ natural killer cells were present. TIL but not PBL contained 12%-19% of lymphocytes which expressed activation markers such as DR and TAC. The culture of both TIL and PBL in IL2 for 2-3 weeks induced an increase in the percentage of CD8+ and a decrease in CD4+ and augmentation of Leu 19+, DR+, and TAC+ cells. These results indicate that IL2-TIL can lyse autologous tumor cells slightly better than IL2-PBL, although such an effect was also evident against allogeneic neoplastic targets.

Cell Line↗
PubMed1989

Cancer patients' lymphocytes contain CD3+ CD4+ cells that proliferate in response to autologous tumor cells in the presence of exogenous low-dose interleukin-2 and autologous accessory cells.

To see whether cancer patients possess CD3+ CD4+ lymphocytes able to proliferate in response to autologous tumor cells (Auto-Tu), this lymphocyte subset was isolated either by positive or negative selection, both methods resulting in highly enriched CD4+ populations. Unseparated and isolated CD3+ CD4+ lymphocytes were then assayed for proliferating activity in the presence or absence of various amounts of Auto-Tu, with or without recombinant interleukin-2 (IL-2) (1.5-15 U/ml) and DR+ adherent cells or E- lymphocytes as autologous accessory cells (Auto-AC). Isolated CD3+ CD4+ lymphocytes were stimulated by Auto-Tu alone in only 1 out of 12 cases. CD3+ CD4+ cells failed to proliferate significantly in response to low doses of IL-2 alone but the addition of Auto-Tu caused stimulation in 8 out of 12 cases (67%). The further addition of Auto-AC to Auto-Tu + IL-2 resulted in enhanced response of isolated CD3+ CD4+ lymphocytes in 6 out of 8 cases tested. When reactivities to Auto-Tu in the presence of IL-2 and IL-2 + Auto-AC were considered together, positive responses of CD3+ CD4+ lymphocytes were seen in 11 out of 12 cases (92%). On the other hand, unseparated lymphocytes were stimulated by Auto-Tu alone in none out of 12 cases. Unseparated lymphocytes, however, responded to IL-2 in 11 out of 12 cases; such a response was increased by the addition of Auto-Tu in only 2 cases. Moreover, the IL-2 proliferation of unseparated lymphocytes was suppressed in 4 and in 3 out of 12 cases tested when Auto-Tu or Auto-Tu + Auto-AC were added respectively. These data indicate that lymphocytes of cancer patients contain CD3+ CD4+ cells that are usually unable to proliferate in response to Auto-Tu only. This proliferation, however, occurs when low doses of exogenous IL-2 are present and can be further amplified by the addition of Auto-AC. No response of CD4+ cells is observed in the presence of DR+ Auto-AC + IL-2 except in 2 out of 7 cases tested (28%), suggesting an Auto-Tu-restricted reactivity of CD3+ CD4+ lymphocytes in the majority of cases.

Antigen-Presenting Cells↗
PubMed1989

Early responder myeloma: kinetic studies identify a patient subgroup characterized by very poor prognosis.

In order to assess the prognostic value of rapid tumor mass reduction in responding multiple myeloma (MM) patients, 100 consecutive patients were analyzed, and bone marrow plasma cell kinetic characteristics were evaluated at diagnosis. Forty-two patients obtained a tumor mass reduction greater than or equal to 50% with three cycles of chemotherapy and within 3 months (early responder myeloma [ERM]), and 23 in greater than 3 months (slow responder myeloma [SRM]). Survival rates in these two groups were not statistically different (P = .07). The labeling index (LI) of bone marrow plasma cells was significantly higher in ERM patients than in SRM patients (1.8 +/- 2.0 v 0.8 +/- 0.7, P = .006). The LI was used to separate the ERM patients into two well-defined subgroups. ERM patients with a LI greater than or equal to 2% showed a median survival of 16.4 months, whereas ERM patients with a LI less than 2% did not reach the median survival at 46.9 months (P less than .0044). Remission duration was also significantly different: 12.2 months in the high LI subgroup and 26.3 months in the low LI subgroup (P less than .0025). Early response itself does not correspond to shorter remission duration and shorter survival, but it is a poor prognostic factor if associated with a high plasma cell proliferative activity.

Actuarial Analysis↗
PubMed1988

Proliferative and/or cytotoxic activity of lymphocyte clones to autologous human melanoma.

Peripheral blood lymphocytes (PBL) of a patient with metastatic melanoma were cultured with autologous melanoma cells (Auto-Me) and recombinant interleukin 2 (IL-2) (MLTC-PBL). Thirty-five days later, when no cytotoxicity against Auto-Me or K562 was detectable, MLTC-PBL were cloned in the presence of Auto-Me, IL-2 (25 U/ml) and Daudi cells as feeder. Eighty-one growing clones were simultaneously screened for proliferative and cytotoxic activity to Auto-Me. Twenty-two clones proliferated in the presence of Auto-Me only, 29 in the presence of IL-2 only and 41 in the presence of Auto-Me plus IL-2; 12 clones showed cytotoxic activity against Auto-Me. Six clones expressed both cytotoxic and proliferative activity to Auto-Me. The phenotype of 6 proliferative clones tested was CD3+, CD4+, WT31+, CD8-, CD16-, Leu19-, whereas that of 2 cytotoxic-proliferative clones tested was CD3+, CD8+, Leu19+, WT31+, CD4-, CD16-. Specificity analysis of proliferative response of 6 clones and of cytotoxicity of 7 clones, tested on a panel of 14 different target cells, revealed a complex pattern of reactivity, each clone expressing a peculiar specificity. Our results suggest the possibility of isolating, from melanoma patients' PBL, T-cell clones with proliferative activity to Auto-Me and Auto-Me plus IL-2, and T-cell clones which apparently express both proliferative and cytotoxic activity to Auto-Me.

Animals↗
PubMed1988

Susceptibility of chemoresistant murine and human tumor cells to lysis by interleukin 2-activated lymphocytes.

The sensitivity of three different human and murine doxorubicin (Dx)-sensitive or -resistant pairs of tumor cells to recombinant interleukin 2 (rIL2)-activated lymphocytes was studied. In two pairs of these sublines (LoVo human colon carcinoma and B16 mouse melanoma sublines), resistance to Dx was induced in vitro, while in the third pair (9229 human metastatic melanoma clones), Dx resistance was spontaneously present in clone 9229.24. Dx-resistant cells were efficiently lysed by rIL2-activated lymphocytes in a short-term 51Cr release assay; in some experiments a trend toward higher lysis of Dx-resistant cells was present. We then tested the tumor cell growth-inhibitory activity of rIL2-activated lymphocytes in the human tumor clonogenic assay after lymphocyte-tumor coculture. Complete inhibition of tumor cell growth was obtained with five of six sublines or clones (both Dx sensitive and resistant) after 3 to 6 days of coculture at effector lymphocyte/target tumor cell ratios of 5 to 50/1; a maximum 99% inhibition was observed with the melanoma clone 9229.4 even after coculture for 6 days at an effector lymphocyte/target tumor cell ratio of 50/1. By using lower effector lymphocyte/target tumor cell coculture ratios (1, 5, 25/1), it was shown that all the three Dx-resistant cell types were significantly more affected by activated lymphocytes than their Dx-sensitive counterparts. The LoVo/DX subline was also more lysed than its Dx-sensitive counterpart LoVo/H subline by an antitumor monoclonal antibody in a complement-mediated cytotoxicity assay, despite the fact that both sublines expressed a similar amount of antigen on the cell surface. These data indicate that Dx-resistant cancer cells are more susceptible to the lysis by rIL2-activated lymphocytes than their Dx-sensitive counterparts and that a complete inhibition of their clonogenic potential can be obtained in vitro.

Animals↗
PubMed1988

Differential susceptibility to recombinant interferon-gamma-induced HLA-DQ antigen modulation among clones from a human metastatic melanoma.

Twenty-one clones from an early culture of a histocompatibility leukocyte antigen (HLA) class II negative human metastatic melanoma (Me 9229) were screened for susceptibility to phenotypic modulation induced by recombinant interferon-gamma (rIFN-gamma) by using SPV-L3, a monoclonal antibody to HLA-DQ antigens, in indirect immunofluorescence followed by fluorescence-activated cell sorter analysis. After treatment with 500 U/ml of rIFN-gamma for 3 days one of the clones (9229/18) expressed high levels of DQ antigens, in terms of percentage of positive cells, whereas many other clones were much less susceptible or remained DQ negative. Scatchard analysis of the data of specific binding of 125-I-labeled rIFN-gamma revealed that one clone susceptible (9229/18) and one clone resistant (9229/5) to HLA-DQ modulation expressed similar numbers of interferon-gamma binding sites per cell; dose-response experiments showed that all clones could be induced to express HLA-DR and -DP antigens after exposure to rIFN-gamma. However, the DQ-negative profile of clone 9229/5 was not modified even after incubation with up to 1 X 10(4) U/ml of rIFN-gamma or by extending the culture time in the presence of this lymphokine up to 120 hr. Furthermore, Northern blot analysis indicated a direct correlation between changes in the levels of HLA-DR and -DQ-specific mRNA after rIFN-gamma treatment, and the lack or expression of HLA class II antigens at the cell surface of the two different clones. Karyotype studies did not reveal differences between clones 9229/5 and 9229/18 and Southern blot analysis indicated that both clones had similar EcoRI and HindIII restriction patterns for DR and DQ gene sequences. Finally, strong DQ-specific mRNA signal and antigen expression at the cell surface could be induced even on clone 9229/5 by treating the cells with supernatants from mixed lymphocyte cultures, recently shown to contain a class II-inducing factor different from interferon-gamma. Taken together these results indicate that DQ antigens can be modulated even in clones resistant to rIFN-gamma induction and suggest that the differential susceptibility observed in response to this lymphokine could play a role in the genesis of the phenomenon of intratumor heterogeneity.

DNA, Neoplasm↗
PubMed1988

Lack of suppressive activity of human primary melanoma cells on the activation of autologous lymphocytes.

Previous studies have indicated that primary but not metastatic melanomas were able to stimulate the proliferation of autologous (Auto) peripheral blood lymphocytes (PBL) in 73% of cases. On the other hand, 57% of the metastatic melanomas were shown to be suppressive when melanoma cells (Me) were admixed with Auto-PBL stimulated with allogeneic (Allo) PBL or interleukin 2 (IL-2) at the beginning of a 6-day incubation period. Here, we report that the suppressive activity of Me is a functional characteristic associated with a particular stage of the disease. In fact, we found that none of the 11 primary tumors tested were able to inhibit the proliferative response of Auto-PBL to Allo-PBL or IL-2 at all the doses of tumor cells used. The generation of lymphocytes cytotoxic against Auto-Me or K562 was also not inhibited. Of the 11 primary tumors checked for suppression, 8 were able to stimulate Auto-PBL in a primary mixed lymphocyte tumor culture. We conclude that opposite functions, stimulation and inhibition of autologous lymphocyte responses are characteristics of primary and metastatic Me, respectively.

Cytotoxicity Tests, Immunologic↗
PubMed1988

Activated idiotype-reactive cells in suppressor/cytotoxic subpopulations of monoclonal gammopathies: correlation with diagnosis and disease status.

The phenotypic pattern of peripheral blood T (PBT) lymphocytes was correlated with diagnosis and clinical status in 63 patients with monoclonal gammopathies (MGs). The numbers of lymphocytes expressing activation and CD11 determinants were significantly increased in suppressor/cytotoxic and helper/inducer subpopulations of patients with multiple myeloma (MM) and MG of undetermined significance (MGUS). The number of activated suppressor/cytotoxic cells was closely correlated with diagnosis and disease status. These cells were significantly higher in MM at diagnosis (160 +/- 88) than MGUS patients (61 +/- 79; P less than .01). Their number decreased to MGUS levels in MM in stable remission (58 +/- 53), but not in MM with tumor progression (172 +/- 102; P less than .001). In individual patients, part of these cells specifically adhered to dishes precoated with the related M-protein. No monoclonal T-beta gene rearrangement was detected in PBT and cytotoxic/suppressor subpopulations from two patients with a large proportion of activated cells.

Blood Proteins↗
PubMed1988

Tumorigenicity and dissemination of primary and metastatic human melanomas implanted into different sites in athymic nude mice.

In the present study, the growth features and metastatic capacity of human primary and metastatic melanomas transplanted by different routes in nude mice was examined. Eight different human melanoma early cell cultures derived from 3 primary tumors, 1 local recurrence and 4 metastatic lesions of 6 melanoma patients were characterized for cell surface HLA (class I and II) and melanoma-associated antigens and karyotype. These tumors were then transplanted in CD-1 outbred nude mice by subcutaneous, intraperitoneal and intrasplenic routes. It was found that 7 out of 8 melanomas were tumorigenic after subcutaneous implantation without giving rise to metastases; 5 out of 7 melanomas grew when injected intraperitoneally and 3 of them disseminated to peritoneal organs and infiltrated intraperitoneal lymph nodes, liver and pancreas; of 8 melanomas implanted intrasplenically 4 grew in the spleen or invaded intraperitoneal lymph nodes, liver, pancreas, ovaries or lungs. Primary and metastatic melanomas did not differ in the pattern of dissemination. In fact, 2 out of 4 metastases and 1 of 3 primary tumors and 1 recurrence disseminated after intrasplenic or intraperitoneal inoculation. Heterogeneity in the growth pattern of different metastases of the same melanoma patient was also found. No correlation could be detected between the metastatic ability of melanoma cells studied and clinical stage of patients, tumor cell karyotype abnormalities, modal number or with the antigenic phenotype.

Animals↗
PubMed1987

Melanoma cell lysis by human CTL clones: differential involvement of T3, T8 and HLA antigens.

Three lymphocyte clones, derived by micromanipulation from peripheral blood lymphocytes (PBL) of a melanoma patient and expressing a broad pattern of reactivity against different target cells, were analyzed for the involvement of T-cell markers and HLA antigens in the lysis of target cells by blocking experiments with a panel of monoclonal antibodies (MAbs). The clones lysed autologous melanoma cells (Me 28) and 18 out of 22 allogeneic targets including neoplastic and normal cells of different histological origin. Anti-T3 and anti-T8 MAbs strongly inhibited the cytotoxicity of the lymphocyte clones against Me 28, 3 allogeneic melanomas and 3 carcinomas, but failed to affect the lysis of K562. Anti-HLA class-I MAb (w6/32) produced a significant enhancement of the lysis of Me 28 by the 3 clones without modifying cytotoxicity against one allogeneic melanoma or against K562 cells. Anti-HLA class-II MAb (D1.12) did not affect the lysis of the same targets by the 3 clones. These results thus indicate that some anti-melanoma CTL clones may interact with autologous tumor cells by the T3 and T8 structures in an HLA class-I unrestricted manner.

Antibodies, Monoclonal↗
PubMed1987

Lysis by activated lymphocytes of melanoma and small cell lung cancer cells surviving in vitro treatment with mafosfamide.

Six short term-cultured melanoma cell lines and one small cell lung cancer cell line were treated in vitro with the alkylating agent mafosfamide. The sensitivity of the surviving cells to in vitro lysis by recombinant interleukin 2-activated autologous and allogeneic lymphocytes was then investigated. In no case did chemo-surviving tumor cells appear less sensitive to lymphocyte-mediated lysis than untreated counterparts. In three of seven cases (two of which were derived from the same patient), chemo-selected cells were even more sensitive to cytotoxic lymphocytes, a difference not explained by a different distribution of neoplastic cells in the various cell cycle phases. We also studied the inhibitory activity of activated lymphocytes on the clonogenic potential of chemo-surviving tumor cells by the human tumor clonogenic assay. Inhibitions of tumor cell growth in the two patients tested were 100 and 94%, respectively; the activity of lymphocytes was dependent on the coculture time and the effector/target cell ratio. These data indicate that in vitro treatment with mafosfamide does not select cells resistant to the action of activated lymphocytes and that, given the right experimental conditions, these immune effectors can completely lyse tumor cells.

Carcinoma, Small Cell↗