Abstract OT2-03-02: DI study: Decision impact of the NanoString® Technologies Prosigna™ in early breast cancers

Backgrounds: More than a decade of research, clinical studies, and peer reviewed publications support the value of molecular subtyping based on gene expression analyses to assess prognosis and treatment options for patients with early-stage breast cancer. Therefore, genomic assays are now being introduced to supplement the conventional diagnostic tools. Prosigna is a standardized test that measures the expression levels of 50 classifier genes in formalin-fixed, paraffin-embedded (FFPE) breast tumor tissue samples and provide a subtype classification based on the fundamental biology of individual patient's tumor (referred to as molecular subtyping), as well as a prognostic score (referred to as risk of recurrence (ROR) score) that predicts the probability of cancer recurrence over 10 years.

The primary objective of this study is to assess the extent to which Prosigna affects the medical oncologist's treatment recommendations regarding adjuvant chemotherapy and actual treatments received for patients with early-stage breast cancer. Changes will include hormonal therapy alone, hormonal therapy plus chemotherapy, and changes in types of chemotherapy if chemotherapy was recommended before and after the test. Secondary objectives will be to elicit information on investigators' confidence in the recommendations before and after the test, and by cancer recurrence risk groups, rate of chemotherapy related adverse events stratified by administration of chemotherapy, and patients' decisional conflict status, anxiety levels, and functional status before and after Prosigna results.

Multicentric prospective study. Prosigna will be performed on operative piece for all consecutively postmenopausal women matching the inclusion criteria and having signed an informed consent. Data on patient demographics, disease status, intended cancer-specific postoperative management before and after the test, tests results, investigators and patients' confidence in the treatment and in the test, will be recorded in the inclusion visit, after the tests results and 6 month post-assay.

Inclusion criteria: Postmenopausal patients with resected node-negative, estrogen-receptor-positive, HER2-negative (by the local laboratory) early-stage invasive breast cancer (T1-T2, N0, pN0 (i+), pN1 (micrometastatic), M0), able to give consent, eligible for treatment of breast cancer with adjuvant chemotherapy and with ECOG performance status of 0 or 1.

Statistical methods: The clinical and demographic characteristics of the study sample will be described using mean, median, standard deviation, and range for continuous/ordinal variables and frequency and proportion for categorical variables. Bivariate plots and crosstabs will be performed to inspect bivariate associations between variables. The proportion of patients for whom the physicians' choice of treatment changed from baseline to follow-up will be calculated along with the 95% confidence interval. The change in investigator confidence in treatment recommendations before and after Prosigna results were known will be analyzed by calculating the mean and 95% CI for the question regarding whether a physician is more confidence in treatment recommendation after ordering Prosigna.

47 patients have been included on 200 scheduled.

Citation Format: Lerebours F, Hequet D, Guinebretière J-M, Roulot A, Callens C, Gentien D, Penault-LLorca F, Zilberman S, Salmon R, Foa C, Berseneff H, Huchon C, Katz G, MacDonald M, Morel P, Bieche I, Dubot C, Rouzier R. DI study: Decision impact of the NanoString® Technologies Prosigna™ in early breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT2-03-02.

[Guillain-Barré syndrome and non-Hodgkin's lymphoma. Report of one case and review of literature]

Patients with lymphoma frequently develop neurologic abnormalities mainly due to nervous system infiltration but also direct drug toxicity. Moreover Guillain-Barré syndrome (GBS) remains a possible neuropathy, rarely described in non-Hodgkin's lymphoma. We describe a case of GBS in a patient with non-Hodgkin's high grade lymphoma. A 74-year old man with a newly diagnosed stage I high-grade lymphoma (precursor B-cell Burkitt like type according to the R.E.A.L. Classification) develop flaccid quadriparesis, 7 days after the end of the third course of CHOP treatment. The clinical course and neurological examination were consistent with GBS. The patient was in tumoral complete response. Despite appropriate treatment and a transfer in a reanimation unit, the patient died 3 days after the beginning of neurologic symptoms. The low number of cases described in the international literature doesn't permit to understand the association of this neurologic disease with non-Hodgkin's lymphoma. Collecting more data could lead interesting information to know the place of malignant hematological disease in the natural history of GBS.

A Weekly Schedule of Docetaxel for Metastatic Hormone-Refractory Prostate Cancer

RATIONALE

Docetaxel has proven its efficacy in the management of hormone-refractory prostate cancer (HRPC). Schedules of docetaxel administration differ. This prospective phase II study was designed to reevaluate the activity and toxicity of docetaxel administered weekly at an optimal dose to a large cohort of HRPC patients.

PATIENTS AND METHODS

Sixty-four patients were treated with docetaxel 40 mg/m(2) i.v., administered weekly for 6 consecutive weeks followed by a 2-week recovery period. Three treatment cycles were planned in the absence of progression or toxicity. The principal end point was the biochemical response based on the prostate-specific antigen (PSA) level (a decline of more than 50% for at least 4 weeks). Secondary end points were objective response to measurable disease, survival and toxicity.

RESULTS

Toxicity was assessed in 64 patients. Toxicity was acceptable, with no toxicity-related deaths. Twenty-one percent of the patients developed grade 3-4 hematological toxicity. Sixty-four patients were evaluable for the PSA response. Forty-one patients (64%) achieved a decrease in PSA of >50%, 13 of whom had a PSA <4 ng/ml. Two out of 12 patients with measurable disease exhibited an objective response. With respect to PSA, the median progression-free survival was 29 weeks (95% confidence interval: 18-46 weeks). The global 1-year survival rate was 58%.

CONCLUSION

Weekly docetaxel at a dosage of 40 mg/m(2) is a well-tolerated treatment, which has very promising activity on the reduction of PSA in metastatic HRPC. A large phase III study is underway.

Traitement des images et radiothérapie

Medical images are of great importance in radiotherapy, which became a privileged application field for image processing techniques. Moreover, because of the progression of the computers' performances, these techniques are also in full expansion. Today, the recent developments of the radiotherapy (3DCR, IMRT) offer a huge place to them. Effectively, they can potentially answer to the precision requirements of the modern radiotherapy, and may then contribute to improve the delivered treatments. The purpose of this article is to present the different image processing techniques that are currently used in radiotherapy (including image matching and segmentation) as they are described in the literature.

Clinical prognostic factors for patients with recurrent head and neck cancer: implications for randomized trials

The purpose of our study was to determine the clinical prognostic factors for the duration of the overall survival from recurrence (OSR) in patients with recurrent head and neck squamous-cell carcinoma. We performed a retrospective analysis on 496 patients treated between 1982 and 1993 at the Antoine Lacassagne Center. The significant favorable prognostic factors for the OSR were: initial T(1-2) (p = 0.008), no initial nodal involvement (p = 0.002), no initial chemotherapy exposure (p = 0.002), induction chemotherapy response (p = 0.001), duration of disease-free interval (DFI; p = 0.0001), performance status (PS) 0-1 (p = 0.004) and local-regional recurrence (p = 0.001). In the multivariate analysis, the apparent nonsignificance of all factors apart from the DFI suggested that relevant prognostic factors could be embedded in the DFI. Multivariate analysis was performed after excluding the DFI. The results indicated that local-regional recurrence, PS 0-1 and no initial chemotherapy exposure remained significant favorable prognostic factors for the OSR. The advantages of taking into account such prognostic factors are to eliminate the patient selection bias and to ensure a fairer comparative evaluation of new or already existing agents in recurrent head and neck cancer.

Primary lung sarcomas: long survivors obtained with iterative complete surgery

Primary lung sarcomas are uncommon histologic types of primary lung cancer and presents a wide spectrum of clinical behaviour. Nine patients treated at Antoine Lacassagne Cancer Center between 1982 and 1995 were studied. The median age was 63 years (range, 35-73 years) and the most common histologic types were malignant fibrous histiocytoma (four) and leiomyosarcoma (three). All of them underwent surgery, six patients had a complete surgery and three patients incomplete resections. The median overall survival for all patients was 36 months. In the subgroup of patients with initial complete resection, the median survival was significantly longer (47 months) than in the subgroup of patients with incomplete resection (6 months) (P<0.05, log-rank test). Moreover, two patients had a second complete resection for ipsilateral lung relapse and were long survivors (overall survival of 58 and 83 months, respectively). The ability to achieve a complete second surgery stress the possible benefit of an early detection of local recurrence. Because no specific symptom was linked with the local relapse, a systematic CT scan every 2 or 3 months could be required.

Comparison between nasogastric tube feeding and percutaneous fluoroscopic gastrostomy in advanced head and neck cancer patients

Wasting is a major complication of advanced head and neck cancer and the aim of this study was to compare nasogastric tube feeding (NG) and percutaneous fluoroscopic gastrostomy (PFG) in these patients. The goal of these two methods of nutritional support was to improve or maintain the initial nutritional status during treatment. A total of 90 patients, all stage IV oropharynx or hypopharynx tumor, were reviewed from a prospective databank. All these patients were treated by concomitant chemotherapy and twice-daily continuous radiotherapy with no acceleration. Fifty patients were managed by PFG, and the rest by NG. Mechanical failure, duration of feeding, complications, nutritional evaluation and quality of life were analysed. Mechanical failure occurred in 32 of the 40 NG patients and in seven of the gastrostomy group. In the PFG group, 80% of patients conserved their nutritional support after the end of the radiotherapy, none patient in the NG group. In the PFG group, two presented a wound infection and six had aspiration pneumonia while in the NG group, 21 had aspiration pneumonia probably due to the NG tube (gastroesophageal reflux). The feeding methods were found to be equally effective at maintaining body weight and body mass index at time 1 (3 weeks) and at time 2 (6 weeks). Advantages were associated with PFG cosmesis, mobility and quality of life. PFG is a safe and effective method of providing enteral nutrition during treatment to patients with advanced head and neck cancer and offers important advantages over NG.

[Testicular seminoma and multifocal aseptic osteonecrosis following chemotherapy]

INTRODUCTION

Multifocal osteonecrosis has a wide variety of etiologies, but in the cancer patient several risk factors could have a synergic effect (chemotherapy, radiotherapy, corticosteroid, metabolism disorder).

EXEGESIS

A patient with testicular seminoma receiving cisplatin-based chemotherapy and short-term corticosteroid developed multifocal osteonecrosis. Early diagnosis of osteonecrosis is important to prevent orthopedic complications.

CONCLUSION

Cisplatin could represent one of the possible etiologies of multifocal osteonecrosis. Magnetic resonance imaging has a high sensitivity and specificity in the diagnosis of osteonecrosis and should be used when this condition is suspected.

Comparative CD43 behavior on monocytes and lymphocytes in kidney transplants

In human cultured monocytic cells stimulated by cytokines, CD43 was demonstrated to exhibit a modification of sialylated epitopes (dys-sialylation) [Soler et al: Leukoc Biol 1997;61:609-618]. Therefore, we chose to investigate CD43 behavior on patients who present pathological status implicating monocytes after renal graft (KTR). We performed flow cytometry after immune staining using monoclonal antibodies to CD43 sialic acid-dependent (L60) and -independent (L10) epitopes. Compared to normal controls, mean fluorescence intensity was never altered on lymphocytes. Conversely, on monocytes, we found different profiles with L60: 26% of patients having normal CD43 expression, 54% displayed decreased values and 20% had a double population of monocytes, the major one being normal and the minor one with a very low staining. Decreased values were more frequent among KTR during the first 3 months following transplantation. L10 immunostaining was not altered on monocytes in patients with low values of CD43 staining by L60, confirming that the mechanism involved was a CD43 dys-sialylation. We investigated a possible role of cyclosporin (CsA) on human monocytic (THP-1) and lymphoid (Jurkat) cell lines. CsA decreases CD43 expression in monocytic and not in lymphoid cell lines and could be responsible for the specific dys-sialylation of KTR monocytes. Whatever, CD43 dys-sialylation might lead to functional abnormalities of monocytes in KTR, possibly involving the adhesion process.

An analysis of potential factors allowing an individual prediction of cisplatin-induced anaemia

Severe cisplatin (CP)-induced anaemia significantly impairs the patient's quality of life. Prevention based on erythropoietin (EPO) administration would be cost-effective providing that individual predictive factors of anaemia are identified. The aim of the present study was to identify parameters able to predict the occurrence of CP-related anaemia. This prospective study was conducted on 40 head and neck cancer patients receiving a CP (100 mg/m(2), intravenous (i. v.) on day 1) - 5-fluorouracil (5-FU, 1 g/m(2)/dx5 days by continuous infusion) induction chemotherapy. Three cycles were given at 3-weekly intervals. Platinum pharmacokinetics (total and ultrafilterable plasma platinum concentration measured 16 h after CP administration) and 5-FU pharmacokinetics (full-cycle plasma area under the curve, (AUC(0-105h)30 g/l) occurred in 15 patients (38%) and 3 of them also received a blood transfusion. Patient age, 5-FU AUC(0-105h) and total platinum concentration were unrelated to Hb loss. In contrast, ultrafilterable (UF) platinum concentration was significantly correlated to Hb loss: the higher the UF platinum concentration, the greater the Hb loss (P=0.015). A discriminant analysis allowed a cut-off value for UF platinum to be proposed to identify patients developing significant loss of Hb: 91% of patients exhibiting a UF platinum concentration above 50 ng/ml developed significant loss of Hb in contrast to 18% in the group of patients with a UF platinum concentration below 50 ng/ml (odds ratio (95% confidence interval, CI) of 46 (4.7-446)). In conclusion, the present platinum pharmacokinetic survey may be proposed as a valuable approach to identify patients at risk for developing severe anaemia.

Glycocalyx modulation is a physiological means of regulating cell adhesion

Here we present experimental evidence that phagocytic cells use modulation of specific components of their glycocalyx to regulate their binding capacity. Particles coated with antibodies specific for the CD32 medium affinity IgG receptor were driven along human monocytic THP-1 cells (expressing CD32) in a flow chamber operated at low shear rate. Surprisingly, only minimal adhesion was observed. However, when cells were activated by exposure to fibronectin-coated surfaces and/or soluble γ interferon, adhesion efficiency was dramatically increased, whereas the apparent glycocalyx thickness displayed 20% decrease, and the surface density of CD43/leukosialin carbohydrate epitopes displayed 30–40% decrease on activated cells. The existence of a causal link between adhesion increase and glycocalyx alteration was strongly supported by the finding that (i) both phenomena displayed similar kinetics, (ii) an inverse relationship between THP-1 cell binding capacity and glycocalyx density was demonstrated at the individual cell level, and (iii) adhesion enhancement could not be ascribed to an increased binding site density or improved functional capacity of activated cells. Additional experiments revealed that cell-to-particle adhesion resulted in delayed (i.e. more than a few minutes) egress of CD43/leukosialin from contact areas. Since the time scale of particle attachment was less than a second, surface mobility should not affect the potential of CD43 to impair the initial step of adhesion. Finally, studies performed with fluorescent lectins suggested that THP-1 cell activation and increased adhesive potential were related to a decrease of O-glysosylation rather than N-glycosylation of surface glycoproteins.

Sonographic discovery of a pharyngocele

Cervical sonography was performed in a 25-year-old man who was referred to our department because of the recent appearance of a left anterolateral cervical mass. This mass had the sonographic properties of air; it communicated with and extended the piriform sinus as well as deformed the left lamina of the thyroid cartilage. A preliminary diagnosis of left pharyngocele was confirmed by CT. To our knowledge, this is the first sonographic description of such an abnormality.

Adhesion-related glycocalyx study: quantitative approach with imaging-spectrum in the energy filtering transmission electron microscope (EFTEM)

Large polysaccharide molecules composing the glycocalyx have been shown to prevent cell adhesion. However, this process was not observed microscopically. Terbium labeling, combined with a new quantitative imaging method based on electron energy loss spectroscopy, allowed specific glycocalyx staining with excellent contrast. Image analysis enabled us to compare glycocalyx structure in free membrane areas and contacts between monocytic cells and bound erythrocytes. Apparent glycocalyx thickness, in contact areas, was half of the sum of glycocalyx thicknesses in free areas without label density increase. Ultrastructural immunogold localization of CD43 molecules, a major component of glycocalyx, was also demonstrated to be excluded from contact areas during adhesion. Thus, both approaches strongly suggest that some glycocalyx elements must exit from contact to allow binding of adhesion molecules.

Thymocytes in Thy-1-/- mice show augmented TCR signaling and impaired differentiation

Thy-1, a single variable-like immunoglobulin superfamily domain anchored in the plasma membrane by a glycosyl phosphaditylinositol tail [1], is a major surface glycoprotein in adult mammalian neurons and rodent thymocytes [2]; the function of Thy-1 has remained enigmatic since its discovery [3]. Studies in vitro have implicated Thy-1 in homotypic and heterotypic cell-cell interactions [2,4]. Ligation of Thy-1 initiates transmembrane signaling pathways that lead to diverse physiological outcomes in different cells [2,5-7]. In rodents, Thy-1 is highly expressed on the surface of CD4+CD8+ double-positive immature thymocytes and downregulated in mature T cells. Here, we report that thymocytes from Thy-1-/- mice [8] had altered cell-cell contacts, and hyperresponsiveness to T-cell receptor (TCR) triggering as demonstrated by the heightened activation of p56lck, phosphorylation of TCR subunits, Ca2+ fluxes and cell proliferation. Thy-1-/- thymocytes exhibited impaired maturation from the double positive to single positive stage of thymocyte development, possibly due to inappropriate negative selection, and were prone to T lymphomas in aged mice. These observations indicate that Thy-1 negatively regulates TCR-mediated signaling and controls activation thresholds during thymocyte differentiation.

Leukosialin (CD43) behavior during adhesion of human monocytic THP-1 cells to red blood cells

To understand the modulation and the behavior of glycocalyx elements during adhesion, we explored one of its components, the CD43 molecule, on human monocytic THP-1 cells exposed to cytokine stimulation and its redistribution during heterotypic adhesion to opsonized erythrocytes. First we demonstrated by immunofluorescence and immunoprecipitation that CD43 is dys-sialylated in monocytic THP-1 cells stimulated by interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) and stimulation increased correlated to heterotypic adhesion. CD43 anti-adhesive effect seemed to be related to sialic acid moeties because an increase in adhesion was also induced by sialidase treatment and by monoclonal antibodies recognizing sialic acid-dependent epitopes on CD43. Second, a redistribution of CD43 molecules was observed after adhesion, resulting in the exclusion of CD43 molecules from contact areas as demonstrated by immunofluorescence and by ultrastructural immunogold localization. We therefore demonstrated in monocytic THP-1 cells that some glycocalyx molecules can be modulated by cytokines and redistributed during adhesion. These results support the concept that CD43 can regulate cell interactions.

Programmed cell death in Dictyostelium

Programmed cell death (PCD) of Dictyostelium discoideum cells was triggered precisely and studied quantitatively in an in vitro system involving differentiation without morphogenesis. In temporal succession after the triggering of differentiation, PCD included first an irreversible step leading to the inability to regrow at 8 hours. At 12 hours, massive vacuolisation was best evidenced by confocal microscopy, and prominent cytoplasmic condensation and focal chromatin condensation could be observed by electron microscopy. Membrane permeabilization occurred only very late (at 40–60 hours) as judged by propidium iodide staining. No early DNA fragmentation could be detected by standard or pulsed field gel electrophoresis. These traits exhibit some similarity to those of previously described non-apoptotic and apoptotic PCD, suggesting the hypothesis of a single core molecular mechanism of PCD emerging in evolution before the postulated multiple emergences of multicellularity. A single core mechanism would underly phenotypic variations of PCD resulting in various cells from differences in enzymatic equipment and mechanical constraints. A prediction is that some of the molecules involved in the core PCD mechanism of even phylogenetically very distant organisms, e.g. Dictyostelium and vertebrates, should be related.

A novel role for E- and P-selectins: shape control of endothelial cell monolayers

The migration of neutrophils from blood vessels to peripheral tissues is a key step of inflammation. This requires the formation of transient gaps between endothelial cells with concomitant leucocyte squeezing through these narrow apertures and immediate restoration of endothelium continuity. It is currently considered that the main role of selectins is to mediate the initial contact between flowing leucocytes and endothelial cells. We show here that the binding of E- or P-selectins by specific antibodies induces a marked ‘rounding up’ of interleukin-1- or thrombin-activated human endothelial cells, respectively. Also, anti-E-selectin antibodies trigger a transient increase in cytosolic calcium involving intracellular calcium stores. No such effect is observed when von Willebrand factor or intercellular adhesion molecule 1 are similarly bound. Thus, in addition to promoting the initial interaction between activated endothelium and moving leucocytes, selectins might play a role in the induction of subsequent endothelial deformation, which would facilitate leucocyte arrest and transmigration towards peripheral tissues, and enhance the diffusion of soluble molecules between intravascular and peripheral compartments. Our results are consistent with this hypothesis and demonstrate a new property of endothelial selectins.

Relationship between phagosome acidification, phagosome-lysosome fusion, and mechanism of particle ingestion

The fate of pathogens ingested by macrophages is dependent on phagosome acidification and fusion with different intracellular vesicles. Whereas the mode of particle recognition by the phagocyte seems the main determinant of phagosome-lysosome fusion, the influence of membrane reorganization, fusion events, and cell activation in phagosome acidification is not well known. We looked for a relationship between the nature of receptors involved in phagocytosis, phagosome acidification, and phagosome-lysosome fusion. Murine macrophage-like P388D1 cells were made to ingest sheep erythrocytes coated with immunoglobulin G (EIgG) or IgM and complement (EIgMC) or treated with glutaraldehyde and periodate (EGP). The following results were obtained: (1) As expected, the adhesion of the three particle types was differentially inhibited by monoclonal antibodies specific for Fc gamma RII and CD11b/CD18. (2) The phagosomes containing all three particle types displayed similar acidification kinetics with a pH decrease to 6 within the first 10 min after ingestion. (3) Only phagosomes containing EIgG or EIgMC were fused with peroxidase-loaded secondary lysosomes. (4) Coating EGP with IgG only partially restored fusion, even when the surface density of IgG was markedly higher than found on EIgG. It is concluded that phagosome acidification and fusion are regulated by different mechanisms. Also, the lack of fusion observed with EGP is not entirely accounted for by the absence of stimulation of suitable receptors on the phagocyte membrane, because it cannot be restored by providing such a stimulus.

Localization of calcium changes in stimulated rat mast cells

We studied intracellular free, bound, and sequestered calcium in rat mast cells after various stimulations. The use of a fluorescent probe combined with digitized imaging on individual living cells demonstrated transient increases of free Ca2+ in the micromolar range. The use of histochemical techniques (K pyroantimonate and anhydrous fixation), together with X-ray microanalysis, energy electron-loss spectroscopy, and electron spectroscopic imaging, revealed large amounts of stored calcium within the cells (in the millimolar range). Chelation experiments and stimulations enabled us to identify at least two pools of bound calcium which exhibited different dynamic behaviors. Stimulation in the presence of EGTA did not modify calcium from granules, granule membranes, and heterochromatin, whereas it decreased calcium from other cell compartments. Stimulation triggered variations in the amount of bound calcium but they did not parallel free calcium movements. Hence, whereas free calcium is implicated in exocytosis, bound calcium may be involved in altogether different cell functions.

Motion of cells sedimenting on a solid surface in a laminar shear flow

Cell adhesion often occurs under dynamic conditions, as in flowing blood. A quantitative understanding of this process requires accurate knowledge of the topographical relationships between the cell membrane and potentially adhesive surfaces. This report describes an experimental study made on both the translational and rotational velocities of leukocytes sedimenting of a flat surface under laminar shear flow. The main conclusions are as follows: (a) Cells move close to the wall with constant velocity for several tens of seconds. (b) The numerical values of translational and rotational velocities are inconsistent with Goldman's model of a neutrally buoyant sphere in a laminar shear flow, unless a drag force corresponding to contact friction between cells and the chamber floor is added. The phenomenological friction coefficient was 7.4 millinewton.s/m. (c) Using a modified Goldman's theory, the width of the gap separating cells (6 microns radius) from the chamber floor was estimated at 1.4 micron. (d) It is shown that a high value of the cell-to-substrate gap may be accounted for by the presence of cell surface protrusions of a few micrometer length, in accordance with electron microscope observations performed on the same cell population. (e) In association with previously reported data (Tissot, O., C. Foa, C. Capo, H. Brailly, M. Delaage, and P. Bongrand. 1991. Biocolloids and Biosurfaces. In press), these results are consistent with the possibility that cell-substrate attachment be initiated by the formation of a single molecular bond, which might be considered as the rate limiting step.

Use of conjugates made between a cytolytic T cell clone and target cells to study the redistribution of membrane molecules in cell contact areas

In many models of cell-cell adhesion, it was reported that some cell membrane molecules might be redistributed into contact areas. However, this phenomenon was not subjected to precise quantification. In the present work, fluorescence microscopy, immunolabelling and digital image processing were combined to analyse quantitatively the spatial organization of specific or nonspecific conjugates made with a cytolytic T (CTL) lymphocyte clone (BM3.3) and target cells (EL4 or RDM4). Binding was achieved under calcium-free conditions to study the earliest steps of cell interaction, preceding CTL activation. Fluorescent antibodies were used to label class I histocompatibility molecules on both killer and target cells, and T cell receptor, CD3, CD8 and LFA-1 (CD18/CD11a) on the killer cells. Membrane bilayers were stained with a fluorescent phospholipid, glycoconjugates were labelled with periodic oxidation and Lucifer Yellow uptake, and polymerized actin was revealed with a fluorescent phallacidin derivative. Also, the fine geometry of killer-target interaction area was studied with electron microscopy and computer-assisted contour analysis. It is concluded that: (1) qualitative examination of fluorescence photomicrographs cannot permit accurate comparison between different fluorescence densities. (2) The cell-cell contact area was about fourfold higher in specific conjugates than in non-specific ones. (3) The surface density of adhesion molecules exhibited similar increases (between 30 and 80%) in the contact areas of both specific and nonspecific conjugates. (4) However, the amount of redistributed surface molecules was higher when cell-cell interaction was enhanced either by specific immunological recognition (in specific conjugates) or periodate oxidation. (5) Since redistribution did not require extracellular calcium and it was detected on nonspecific conjugates, this did not require full lymphocyte activation. Spatial reorganization of cell surface molecules may thus be a general consequence of adhesion, cell surface mobility and intermolecular forces.

T-cell-mediated cytolysis: analysis of killer and target cell deformability and deformation during conjugate formation

T-cell-mediated cytolysis is initiated by the formation of strong adhesions between killer and target cells. The present work was aimed at determining whether T lymphocytes might exert some mechanical stress on targets during the binding process. Target S194 myeloma cells were thus conjugated to cytotoxic T lymphocytes (CTLs) raised by mixed lymphocyte culture or a cloned lymphoid line that was no longer cytolytic (TG2OUA2). After incubation periods of various lengths, conjugates were processed for electron microscopy and micrographs were digitized for computerized analysis: the cell surface curvature (at the micrometre level) and rugosity (at the submicrometre level) were quantified in free and adhesion-involved regions. Also, the size of cell interaction areas and the distribution of intermembrane distances were measured. Finally, TG2OUA2 and target cells were aspirated into glass micropipettes with calibrated pressure in order to assay their resistance to deformation by mechanical forces. The following conclusions were suggested. (1) Formation of extensive contact zones (with a linear size of several micrometres) with tight intermembrane adhesion (more than 30% of the membrane contours in adhesive zones were separated by an apparent distance lower than 500 A) was essentially completed within less than one minute. (2) CTLs or TG2OUA2 cells were more villous than their targets, and they seemed to deform in adhesive zones in order to adapt to the target contour, rather than imposing some deformation on the target. This may be a general feature of actively adherent cells. (3) Some CTLs, but no TG2OUA2 cells, exhibited conspicuous protrusions extending towards the bound target. In this case, the target cell but not the CTL displayed markedly increased roughness in the adhesion area. (4) TG2OUA2 cells were more resistant to mechanical deformation than S194 target cells, in accordance with previous reports suggesting that the membrane of CTLs was more resistant than that of target tumour cells. Hence, CTLs might transiently impose mechanical stress on the target membrane during the course of lethal-hit delivery.

Study of CTL and LAK contacts to target cells after treatment with mitomycin C and adriamycin

We tried to understand the role of Mitomycin C and Adriamycin in the increased killing of target cells by Cytotoxic T lymphocytes (CTL) and lymphokine activated killers (LAK). For this purpose, we used an objective method allowing quantitative evaluation of the roughness of cell contours on electron micrographs. We compared the folding of the membranes of LAK and CTL as well as conjugated targets exposed to different treatments. We demonstrated first that CTL and LAK displayed similar morphological patterns: the killer cells were more villous than targets in the free areas, and second that the former cells exhibited significant smoothing on the areas of contact with these targets. These results suggest that the binding process (as distinct from the recognition step) is dependent on killer properties which are the same in CTL, LAK and probably NK cells.

Phenotypic evolution of CTL B-lines in vitro

This study demonstrates that cytolytic T-cell lines exhibit progressive in-vitro modifications of their phenotype and of their growth behaviour and may use different pathways for their multiplication. Comparing three established cell lines, we firstly demonstrated that the expression of LFA-I is stable but the Lyt 2, 3 is rapidly lost. In this case, a high lectin-dependent cytotoxicity appears. Secondly, we demonstrated that two of the cell lines used the interleukin 2-interleukin 2 receptors (IL-2-IL-2R) binding pathway. Two different monoclonal antibodies showed that the IL-2 receptors distribution does not correlate with the number of functional sites which determines the IL-2 requirement. In contrast, the third cell line, although bearing high levels of IL-2 receptors, grows without the addition of IL-2; this cell growth is not inhibited by anti-IL-2 receptors monoclonal antibodies. Thirdly, it appears that the new property of IL-2 independence is associated with acquisition of the simultaneous capacity to induce tumour grafts in nude mice. As it has been recently reported that cytolytic T-lymphocytes against tumour cells could be promising immunotherapeutic agents, the spontaneous malignant transformation of such CTL lines should be taken into account before using them for adoptive immunotherapeutic purposes.

Quantification of cell surface roughness; a method for studying cell mechanical and adhesive properties

The presence on the surface of nucleated cells of a variety of asperities of different size and shape plays a prominent role in cell-cell and cell-substrate interaction. Also, the organization of these asperities is directly related to cellular cytoskeletal elements. In the present report, we describe a simple and objective method of studying electron micrographs to quantify the roughness of cell contours. Constant-length segments of cell boundaries are compared to reference circular segments with common extremities and enclosing the same area. This procedure was performed with a digitizer connected to a microcomputer, and it was used to analyse model contours or electron micrographs of (i) target tumour cells bound by cytotoxic T lymphocytes and (ii) thymocytes sticking to concanavalin A-coated surfaces. It is shown that this method allows precise quantification of cell deformation in adhesive zones, which may allow absolute evaluation of adhesive stimuli.

Study of cell deformability by a simple method

Cell deformability plays an important role in many immunological processes, such as phagocyte chemotaxis and endocytosis. The most widely used method of assay consists in aspirating cells into glass micropipettes and measuring the length of the protrusion induced by a given pressure, or the minimum pressure required to drive cells into the micropipette. This procedure requires specialized equipment and delicate manipulation. The present report describes a simpler procedure: cells are centrifuged in petri dishes floating on a water cushion, then fixed and coated with 0.8 micron diameter latex beads, which allows rapid and accurate determination of their height. This method is compared with the micropipette technique by studying lymphocyte and macrophage-like cell lines in physiological medium and in the presence of a divalent cation chelator or a microfilament inhibitor. In addition to simplicity, the main advantages of this technique are that (i) many cells may be examined within a reasonable period of time, which allows testing of heterogeneous cell populations, and (ii) unexpectedly, centrifugation was quite harmless under our experimental conditions, since it did not impair cell proliferative ability nor phagocytic ability. It is concluded that the method may be used in clinical laboratories to explore phagocyte dysfunctions, as well as in experimental studies.

Unexpected cell surface labeling in conjugates between cytotoxic T lymphocytes and target cells

Specific binding of target cells by cytotoxic T lymphocytes (CTL) is an example of tight interaction between two different cell types. The molecular events that occur at the cell membranes during these interactions are largely unknown. In the present report, we describe an electron microscopic immunostaining study made on CTL-target cell conjugates. Various membrane structures were labeled with monoclonal antibodies specific for structures possibly relevant to cytolysis (Lyt-2, LFA-1, and target cell class I major histocompatibility antigens) or probably unrelated to the cytolytic process (effector cell class I major histocompatibility antigens). Antibodies against Thy-1 were also used. Staining was achieved with immunoperoxidase or immunoferritin. With both techniques nonconjugated cells were either stained or not, depending on whether they bore the antigen corresponding to the antibody used. However, when conjugated to an antigen-bearing cell, a "non-antigen bearing" cell was labeled near the cell interaction area. No increased Fc receptor activity could be detected on bound cells near the interaction area. These data are consistent with the occurrence of limited exchange of membrane macromolecules between bound CTL and target cell.

Functional characteristics of cytotoxic T lymphocyte polyoma virus-transformed fibroblast hybrids

By two different fusions between a cytotoxic T-lymphocyte (CTL) clone and a polyoma virus (Py)-transformed fibroblast line, 40 hybrid clones have been generated. It has been demonstrated that they were all TCGF independent for multiplication. Moreover, some of these hybrids were functional for cytolytic expression, whether or not TCGF was present either at the time of fusion or in the selective media. Two clones generated from the same fusion were markedly cytolytic and were able to remove TCGF from their culture medium, suggesting that they possessed TCGF receptors. These clones also secreted discrete amounts of a TCGF-like factor. The effect of TCGF on hybrid cell proliferation is discussed.

Nonspecific cell surface properties: contact angle of water on dried cell monolayers

Measuring contact angle of water on dried cell or bacterium monolayers allowed van Oss (1) and others (2) to find a correlation between particle hydrophobicity and ingestion by phagocytic cells. The present study was undertaken to understand what was actually assayed with this method. Monolayers were prepared with different cell types at different densities, and they were dried under atmospheres with varying humidity before being studied with scanning electron microscopy and contact angle techniques. It is concluded that a) contact angles are independent of the cell density and substrate structure when more than 30% of the substrate area is covered with cells. b) Initial cell shape should not influence contact angle. c) Contact angles are markedly dependent on the nature of tested cells. d) Contact angles are substantially influenced by the cell drying procedure. e) A very small fraction of the energies we measured would be sufficient to account for cell-cell interactions. Hence these might play a role in some situations of biological interest.

Cytolytically active murine T-lymphocyte/polyoma virus-transformed fibroblast hybrids

It would be of great interest to obtain permanent T-cell lines retaining specific activity without either allogeneic or xenogeneic stimulation. Functionally active hybrids between cytolytic T cells and thymoma were previously reported, but they had to be selected in a TCGF-containing medium. This study contains new results and reports the preparation of a hybrid cell from a cytolytic T cell and a polyoma virus-infected fibroblast, in which the T-cell characteristics dominate over the polyoma-transformed characteristics. A differentiated T-cell function (i.e., cytolysis) persists and the differentiated line does not require TCGF. The loss of cytolytic activity during in vitro evolution may be due to a selection favouring transformed cells, as suggested by concomitant enhancement of the transformed phenotype and chromosome loss.

Functional and ultrastructural alterations of autologous platelets labeled with 111In-oxine

High activity labeled platelets could be useful for the detection and observation of small foci of thrombosis by gamma-camera imaging. Therefore platelets were labeled with 111In-oxine containing increasing activities of 111In to determine the elimiting amount of this tracer that did not cause cell damage. A labeling procedure was employed so that all the chemical parameters remained constant except the amount of 111In. Platelet damage was studied by ADP-induced aggregability according to the Born procedure and by scanning and ultrastructural electron microscopy. Platelets labeled with the lowest activity 2.2 MBq/ml of platelet suspension (10(9) cells/ml) showed no alterations. With the highest activity studied, (22 MBq/ml) aggregability decreased by two-thirds and great changes in the shape of the platelets were seen by electron microscopy. These modifications were attributed to the decay of 111In predominantly located in the platelet cytosol. Labeling of platelets with an activity higher than 7.4 MBq/ml is unsuitable for detection of thrombosis since normal platelet functions are not retained.

Tumorigenicity and tumour-graft rejection of polyoma virus-transformed fibroblast-T-lymphocyte hybrids

In anticipation of the use of functional T-lymphocyte hybrids in adoptive immunotherapy, the differentiation and tumorigenicity of hybrid clones generated by fusion of a T lymphocyte derived from F1 (DBA/J2 x AKR) mouse spleen, and a polyoma virus-transformed fibroblast initiated from C3H mouse cells, were studied. The hybrid cells grew in suspension and had an appearance (by transmission and scanning electron microscopy) very similar to that of the lymphocytic line. The hybrid and the different clones could induce tumour grafts. Malignancy was dominant in newborn mice where tumours were obtained in all mouse strains (allogeneic or semi-allogeneic) inoculated. In adult mice, the hybrid cells were tumorigenic in C3H and F1 (DBA/J2 x AKR), whereas there was complete tumour rejection in allogeneic (C57/BL6) or semi-allogeneic (DBA/J2 and AKR) mice. The role played by major histocompatibility antigens in the graft rejection is discussed. The histology of the tumour grafts was intermediate between fibrosarcoma and lymphosarcoma.

Cell surface fixation of alloantigen bearing plasma vesicles in the presence of polyethylene glycol

The fixation of plasma vesicles at the surface of intact mouse spleen or tumor cells was studied in order to introduce the foreign alloantigens of the vesicles into the plasma membrane of these cells. A 3-6-fold increase of fixation of radioiodinated vesicles was obtained when cells and vesicles were incubated in the presence of polyethylene glycol 1500 (PEG 1500). The fixation of vesicles on the surface of cells was demonstrated by scanning electron microscopy. Cells treated with vesicles in the presence of PEG acquired the corresponding membrane alloantigens, as demonstrated by cellular binding radioimmunoassay. However, sensitivity to antibody-dependent lysis was obtained only when vesicle fixation was achieved in the presence of both wheat germ agglutinin and polyethylene glycol. The introduction of foreign alloantigens in the plasma membrane of the treated cells might help to define the functional properties of these molecules.

Correlation between characteristics of transformation and malignancy of intra and interspecific somatic hybrid cells

The transformed properties of five hybrid cell lines which had either one or another parent in common were studied and compared with their tumorigenicity. Three hybrid cell lines, derived from the Chinese hamster DC-3F/ADX/Aza line, were resistant to actinomycin-D. This property seemed to be correlated with the presence of a marker chromosome from the common parent. The tumorigenicity was intermediate between those of the parent cell lines. On the other hand, agglutinability by concanavalin A (Con A) was variable. Three hybrid cell lines which had either the A9 or the clone 1D (both derived from mouse fibroblasts) showed very similar transformed characteristics, but two were tumorigenic and one not so. It appears from this study that the properties of the hybrid cell lines can be influenced more by one parent, depending on the genes retained at chromosome segregation. The limits of Con A agglutination as a characteristic of transformation and the validity of the check pouch grafts as tumorigenicity test for malignant human cell lines are discussed.