Tumor cell-surface organization: differences between two TA3 sublines

Discrimination of circulating tumor cells of breast cancer and colorectal cancer from normal human mononuclear cells using Raman spectroscopy

Circulating tumor cells present an important marker of the progress of several cancer diseases including breast and colorectal cancer, and enables an interesting prognosis and diagnostic options that can complement convenient diagnostic techniques based on several imaging methods. Based on its relevance, the analysis of such kinds of cells is within the scope of many research and clinical institutes; however, it still presents a difficult task. Here we used a state-of-the-art micro-Raman microscopic technique to enhance possibilities in the study of circulating tumor cells and their further differentiation. As cytospins present a convenient form of sample collection and preparation, we used this form of sampling as the initial point. Raman presents a non-destructive form of sample analysis and thus the samples can be further used for a method validation. We have considered the influence of fixation methods of the cells, where we found out that the ability of Raman spectroscopy to differentiate between three cell lines strictly depends upon the sample preparation method used. Namely breast (BT 549) and colorectal (HCT 116) circulating tumor cell lines and human mononuclear cells were compared. Methanol and paraformaldehyde methods of fixation were compared to simple drying out of the sample. It has been shown that drying out of the cells enables the best performance to be obtained in cell differentiation and this is demonstrated by the use of principal component analysis, where all three given cell lines were differentiated with a high level of confidence. Next, the cells were also scanned using 1 μm spatial resolution. The acquired data were visualized using both chemigrams and hierarchical clustering analysis.

Comparative lectin-binding and agglutination properties of the strain-specific, TA-3-St, and the non-strain-specific, TA3-Ha, murine mammary carcinoma ascites sublines. Further studies of receptors in epiglycanin

The complex carbohydrates at the cell surfaces of two TA3, murine mammary carcinoma ascites sublines (the strain-specific, TA3-St subline and the nonstrain-specific. TA3-Ha line) were compared by binding studies with 125I-labelled concanavalin A (con A), Ricinis communis agglutinin (RCA), and eel-serum agglutinin (ESA). The TA3-Ha cell bound equal amounts of con A, 1.5-fold more RCA, and 4-fold more ESA than the TA3-St cell. Binding-inhibition studies by these lectins and two others [wheat-germ agglutinin (WGA) and potato lectin (STA)] suggest complementary binding-sites between con A and both RCA and ESA. Quantitative agglutination studies with the five lectins, and inhibition determinations by both neuraminidase-treated and untreated epiglycanin revealed that TA3-St, but not TA3-Ha, cells were agglutinated by con A, and that epiglycanin inhibited this agglutination, as well as the agglutination of rabbit erythrocytes by con A. The presence of a con A receptor on epiglycanin was also suggested by the binding of epiglycanin to con A-Sepharose, and its specific elution with methyl alpha-D-mannopyranoside. TA3-St cells were agglutinated at a 10-15-fold lower concentration of either STA or RCA than TA3-Ha cells, but both cells were agglutinated by the same concentration of WGA and ESA. Inhibition by epiglycanin of agglutination of TA3-St cells by either STA or ESA occurred at a concentration lower than that of TA3-Ha cells, but epiglycanin inhibited RCA agglutination of TA3-Hs cells at a concentration lower than that of TA3-St cells. Epiglycanin, but not asialoepiglycanin, inhibited the agglutination of TA3-Ha cells by WGA.

Ultrastructural and histochemical differences in cell surface properties of strain-specific and nonstrain-specific TA3 adenocarcinoma cells

Transmission and scanning electron microscopy and histochemical and biochemical methods were used to investigate differences in cell structure and cell surface properties between the strain-specific TA3-St and nonstrain-specific TA3-Ha ascites sublines of the TA3 murine mammary adenocarcinoma. The TA3-St subline is lethal only to the syngeneic strain A mouse (the strain of origin), whereas the TA3-Ha subline is lethal even to foreign species. In contrast to the TA3-St cell surface, which has numerous folds and irregular microprojections, the TA3-Ha cell has abundant long microvilli of uniform dimensions. An extensive cell surface coat which resembles the "fuzz" coat found on microvilli of normal epithelium was present on the TA3-Ha, but not on the TA3-St cells. After routine fixation, the surface coat of the TA3-Ha cell usually appeared as a filamentous network extending 30-50 nm from the plasmalemma; occasionally, longer filamentous or rod-like structures were found extending 200-400 nm from the plasmalemma. The cell coat material was more extensive on the microvilli than on the intermicrovillous membranes. Free virus-like particles associated with TA3-Ha cells have a similar-appearing surface coat on their outer membranes. The density of surface anionic sites, determined with polycationic ferritin, was greater on the TA3-Ha than on the TA3-St cell surface, consistent with the presence at the TA3-Ha cell surface of several-fold more neuraminidase-susceptible sialic acid groups. The observed surface features of the nonstrain-specific TA3-Ha cell, in comparison to the strain-specific TA3-St cell, are consistent with the suggestion that sialic acid-rich glycoproteins at the TA3-Ha cell surface mask histocompatibility antigens and enhance the ability of malignant cells to invade foreign species.

Effects of local anesthetics on membrane properties. II. Enhancement of the susceptibility of mammalian cells to agglutination by plant lectins

Treatment of untransformed mouse and hamster cells with the tertiary amine local anesthetics dibucaine, tetracaine and procaine increases their susceptibility to agglutination by low doses of the plant lectin concanavalin A. Agglutination of anesthetic-treated untransformed cells by low doses of concanavalin A is accompanied by redistribution of concanavalin A receptors on the cell surface to form patches, similar to that occurring in spontaneous agglutination of virus-transformed cells by concanavalin A. Immunofluorescence and freeze-fracture electronmicroscopic observations indicate that local anesthetics per se do not induce this redistribution of concanavalin A receptors but modify the plasma membrane so that receptor redistribution is facilitated on binding of concanavalin A to the cell surface. Fluorescence polarization measurements on the rotational freedom of the membrane-associated probe, diphenylhexatriene, indicate that local anesthetics produce a small increase in the fluidity of membrane lipids. Spontaneous agglutination of transformed cells by low doses of concanavalin A is inhibited by colchicine and vinblastine but these alkaloids have no effect on concanavalin A agglutination of anesthetic-treated cells. Evidence is presented which suggests that local anesthetics may impair membrane peripheral proteins sensitive to colchicine (microtubules) and cytochalasin-B (microfilaments). Combined treatment of untransformed 3T3 cells with colchicine and cytochalasin B mimics the effect of local anesthetics in enhancing susceptibility to agglutination by low doses of concanavalin A. A hypothesis is presented on the respective roles of colchicine-sensitive and cytochalasin B-sensitive peripheral membrane proteins in controlling the topographical distribution of lectin receptors on the cell surface.